CA2175339A1

CA2175339A1 - Method and apparatus for operating compacting machinery relative to a work site

Info

Publication number: CA2175339A1
Application number: CA002175339A
Authority: CA
Inventors: Adam J. Gudat; Daniel E. Henderson
Original assignee: Individual
Current assignee: Caterpillar Inc
Priority date: 1993-12-08
Filing date: 1994-11-04
Publication date: 1995-06-15
Also published as: AU4734899A; AU1050295A; US5471391A; ZA948825B; DE69416006T2; EP0733231B1; US5493494A; DE69416006D1; WO1995016227A1; JP3585237B2; JPH09508991A; EP0733231A1; AU711136B2

Abstract

A method and apparatus for operating compacting machinery such as landfill earth or asphalt compactors relative to a work site to compact the site material toward a desired degree of compaction. A first model (420) representing the desired degree of compaction of the site (12) and a second model (430) representing the actual degree of compaction of the site (12) are stored in a digital data storage facility (126). The machine (10) is equipped with a position receiver to determine in three-dimensional space the location of the compacting portions of the machine (10) relative to the site (12). A dynamic database (124) receives the machine positon information determines the difference between the degree of compaction of the first and second site models (420 430) and generates representational signals of that difference for directing the operation of the machine (10) to bring the actual degree of compaction of the site (12) into conformity with the desired degree of compaction. In one embodiment, the signals representing the machine position and the difference between the first and second site models (420, 430) are used to generate an operator display (22) which is updated in real time as the machine (10) operates over the site (12). Alternately, the signals representing the difference between the first and second site models (420, 430) can be supplied to automatic machine controls for automatic or semi-automatic operation of the machine (10).

Description

~ Wo 95/16227 21 7 S ~ 3 9 PCT/US9~/12733 METrr~n ANn APPARATUS FOR OP~RATING ~OMPAC~TI~G
IyA~r~r.~RY Rr~r,ATIVE TO A WOR~ SITE
Field of the Ir~vention This invention relates to the operation of machinery for compacting the surface of a work site and, more particularly, to the real time gPn.orAtirn and use of digital data which rrl1~rt;vely represe~ts the degree of compaction of the work site as it is being altered by the m~rhi n~ry toward a desired state .
As used in this patent specification the phrase "compacting ~-rh;nPry~ and various approximations thereof refer to aelf-propelled mobile m-rhi n,os; such ag wheel-type 1 An~lf ; 11, earth and asphalt compactors which exhibit both (l) mobility over a work site as a result of being provided with a prime mover tfor example an engine) on a frame which drives wheels supporting the frame, and (2) the capacity to compact the work site as a conser~uence of the provision on the f rame of one or more wheels or rollers which serve as both carriage support and the compacting tool.
Barkrrr--n~ of the Jnvl~nt;,n Despite the developrlent of sophisticated and powerful compacting m~rhinPry it remain3 a time consuming and labor intensive chore to ader~uately compact r~tf~r; Al such as trash, earth, or asphalt at work sites 3uch as lAn~ , construction sites, roads and the like. The material to be compacted, for example trash or waste ir. a l Anl1~; l l, is typically spread over the site in an uncompacted state and must be repeatedly traversed by a compactor until it is compressed to a predetermined desired degree o~
compaction. ~ common type of compacting m--h; nPry WO 9S/IC227 2 1 7 5 3 ~ 9 pCrl[JS94ll2733 ~

includes one or more heavy ~ _ ~rt; n~ wheels or rollers which compact the material in their path.
Success in achieving the desired degree of compaction of the material on the site is measured, for example, by the number of passes a compacting wheel makes over a given area or by the elevational change f rom the n~ ,~rted level.
Until now compacting operations have largely been monitored and controlled by the machinery operators and supervisors on an intuitive basis, and with the use of static site surveys and physical markers to measure and monitor the compacting operation and the overall topography of the site. For example, after empirically ~t~rm;ninri the number of passes needed to compact the site material to a desired de~ree of~ compaction, the operator drives the compacting machinery back and forth over the site, gauging by memory, feel, visual observation and perhaps comparison to colored stakes or similar physical cues when the desired degree o~ compaction has been reached. Thi~ proces6 is complicated by the fre~uent addition of new, uncompacted material to the site. :~ach time new material is placed on the site, the previous compaction work on that area is effectively erased and the operator must start over in compacting that area. Where the site has not been uniformly c ~,~rt~d prior to the addition of new material, or where the material is added to only a portion of the site while the operator is in the middle of a compacting operation, the 1 ;k~ r,o~l that the ,~ rt;n~J op''rz~t;r~n can be monitored and completed uniformly and rf~;r;~ntly is si,n;~;r~ntly reduced .
For more certain knowledge of the degree to 35 which the u- ~ rted material and the site in general W0 95/16227 _3 _ ~ ~
have been brought into con_ormity with the desired degree of, rtirn and desired site topography, a supervisor or survey crew from time to time verifies the amount of compaction and 3ite build-up and manually updates any staking or marking of the site and the site model. Between these occasional verif ications the compacting --~h i n~ry operators and supervisors have no truly accurate way to monitor and measure their real time progress.
Accordingly, even the most skillful and experienced operators can achieve only limited efficiency in compacting a large land site, such .7iffir7,1ty being due in part to the absence of large scale as well as detailed information as to the real-time progress being made in the compaction of the site .
c7 ry Digclog~7~e of the ~nventinn The invention provides a solution to the long standing problems of np~tin~ compacting machinery to accurately and ~ff;r7~ntly compact material on a work site toward a desired degree of compaction . The sub; ect invention achieves such compacting operations without the need f~or physical markers on the site to cue the operator, with only such interruptions in operation as are needed, for exampler to refuel the machinery, and with a minimum need for crew.
In general this is accomplished through the provision of a digital data storage, retrieval and process facility which per se may be carried on the compacting r--h;n~ry or located remotely from the compacting 7~~~h;n~0ry but r~nn~rtPr7, for example, by radio link to the compacting r-~h;nPry for storing, actually creating, and modifying a digital model of Wo 95/16~27 PCT/U59~/12733 ~
339 ~4~
the aite as it exists at any given time, as well as a digital model of the desired degree of compaction of the site.
The subject invention further comprises a mechanism by which the exact position in three-dimensional space of the ~ t i nr machine, or its operative , -t i n~ wheels or rollers, can be accurately ~lptprm; nPrl in real time ; i . e ., as it moves over and compacts the site thereby to update the digital model, point by point and in real time as the machinery traverses it . As hereinaf ter described the preferred impl ~At;nn of_the invention involves the use of a phase differential GPS (global pos;t;nn;n~
system) receiver system which is capable of precisely locatiny an object in three-~; ~irnAl space to centimeter accuracy.
The sub; ect invention further comprises means for comparing the desired site model to the rnnt;n11mlFIly updated actual site model and for rf~nPr~t ;n~ signals representing the degree~ of compaction needed at each of a large number of coordinates over the site to bring the actual model into conformity with the desired model. These signala may in one instance provide real time displays on or o~ the ~ t;n~ machinery to cue the operator ari to the machine' 8 actual progress in real time and within a frame of reference which conveys information as to at least a substantial portion of the overall site.
In another ~ hereinaf ter described the 6ignals representing the differences between the desired and actual site models are applied to the real time automatic controls of the machine itself or a portion thereof or both.
In a preferred form at least a portion of 35 the position-~ptprm;n;n~ r ' ;rrr, or system is ~ WO 9S/16227 ~17~3~3 PCTIUS94/12733 carried on the compacting machine itself as it traverses the 3ite.
According to another aspect of the invention a method is provided for directing the operations of a mobile compacting machine which comprises the steps of producing and storing in a digital data storage and retrieval means a first site model representing the desired degree of compaction of the site and a second site model representing the actual degree of compaction of the site, thereafter ~Pn,orAtin~ digital signals repr~C~nt; ng in real time the instAntAn~nus position in three-dimensional space of the compacting machine as it traverses and compacts the site, utilizing the digital signals to update the second model, ~t~-rm;n;ng the difference between the first model and the updated second model and directing the operations of the machine in a~.,L~- ~ce with the difference to bring the updated second model into conformity with the first model.
In one embodiment the step of directirlg the operation of the compacting machine is carried out by providing to a machine operator a display which inf orms the operator in real time of the instantaneous position of the, ~At-t;n~ machine relative to the work site, the alterations which are needed to bring the actual degree of ,- , ~ t;nn of the site into conformity with the first model, and the actual progress being made toward the r~oAl;~tinn of the f irst model .
In another: ' -'; ' the step of directing the operations of the compacting machine is carried out in an automatic or semi-automatic fashion by working through electrohydraulic actuators to control the position and direction of -- IV. - of the machine.

W0 95~16227 2, ~ 3 3 ~ - 6 - PCTrUS9.1/12733 In a preferred form at least a E~ortion of the position-~ r~;n;n~ means is carried on the compacting machine itself as it traverses the site.
A8 hereinafter made more explicit, both the 5 apparatus and the method aspect6 of the present invention can be achieved in various ways; for example, the digital data storage and retrieval facility as well as the updating and differencing means may be carried by and on the compacting machine lo as part of an integral and comprehensive on-board machine system. Alternately these means may he located at an off si~ or nearby facility for transmitting visual display signals or automatic control signals to the compacting machine and for receiving updated position and site information from the machine during operation thereof__ As hereinaf ter described in detail the compacting machine may be a wheeled or roller-type co.~-p~t~r such as used, for example, to compact l~n~f;llq, earth or asphalt.
In the preferred form the method and apparatus aspects of the invention are realized through the ~1t;l;7~t;~n of three-dimensional position information derived from global positioning satellites using a phase ll;ffPrPn~;~l GPS receiver system. Such GPS receivers utilize signals from global positioning satellites as well as a differential signal from a local ref erence receiver of known position coordinates to ~n~r;~te position coordinate data to centimeter accuracy. Accordingly, the apparatus used to carry out the invention in the preferred form comprises a GPS receiver having both GPS and local signal reception capabilities and, where a local reference signal at a geodetically surveyed site is not availahle, a t~ ,,oLaLy surveyed diiferential Wo 9~/16227 PCTNS9J/12733 1 73~39 7 receiver/transmitter to provide the local data processing apparatus with a correction signal.
Alternately, raw position data can be transmitted from the reference receiver to the local data processor for 5 comparison and correction with the information from the machine-mounted receiver.
According to another aspect of the invention means are provided for precisely generating and controlling displays which are suitable for use in performing compacting operations on sites such as l~n~ s, construction sites, and roads so as to precisely display the progress being made by the _ ~t; n~ machine on an in~ 1 bagis where the unit areas of the display may or may not correspond to the sampling rate of the GPS receiver and digital processor system. As hereinafter described, the site, or a practically displayable portion thereof, is subdivided into a continuous matrix of unit areas of such size that the compacting machine may traverse these unit areas at a rate which is greater than the sampling rate of the GPS receiver and data processing facility. Algorithms are provided which take into account the physical ~c~, tF~s and dimensions of the compacting wheels or rollers and the relationship 2s thereof to the machine and it8 path of travel. The unit areas o~ the display are filled in, colored, revised or otherwise altered in accordance with progress information derived from the GPS receiver or other positioning 3ystem and the digital processing facility, in accordance with the hereinaf~:er described laws of the algorithm which is in r~ .n~ in the digital processing facility.
In one: ' ,n~i ' of the invention the real-time path of the compacting machine relative to the site between position readings is determined with a W0 95/t6227 ~ 5 3 3 9 PCT/US94/12733 ., differencing algorithm which determines an effective width of a compacting wheel less than or equal to its actual width, and updates each portion of the site model which the effective width tLcLv~Ltsc:s. In a preferred orm the instantaneous position of the machine as it traverses the site is tracked as a series of coordinate points on the site model. Where the rate at which the coordinate points are tracked is not synchronous with the rate of travel of the compacting machine over the unit areas or grid t~l ..m~.n~n of the site, the differencing algorithm determines the unit areas traversed by the compacting wheel of the machine between coordinate points. The effective parameters of the compacting wheel are pref erably set less than its actual parameters to ensure that only those portions of the site actually traversed to some degree by the wheel are filled in, colored, revised or otherwise altered or marked to reflect a compacting pass and the curre~t dif~erence in degree of compaction between the actual and desired site models.
In one embodiment or utilization of the invention the f irst site model is a predetermined -t;nn gtandard for the site topography, representing the I ~ rt i ng operations needed to bring the llnt _-rted t-~VyL~~ or surface material to a desired degree of compaction. One preferred method is the use of a pass count standard; i . e ., the num.~ber of Ct~ rt i nt3 pagges predetermined to bring the 1lnrr-~rted material to the desired degree of ~,~'t;t~n. Alternately, the compacting standard may comprise a change in the elevation of the site surface predetPrm~ nPtl to indicate a desired degree of compaction from an uncompacted level. The system and method of the invention can also monitor and update 95/16227 ~ PCr/US94~12733 ~,9 the overall topography of the 6ite as it is built up or f illed in by repeated additions of new material and the compacting operations.
In one embodiment or utilization of the invention the second or actual site model may be initially created using standard state-o~-the-art site surveying methods to record the actual elevation or :~
topography of the site surface, and thereafter the data from such survey digitized in accordance with the physical and data processing requirements of the partlcular digitizing and data processing system used.
Alternatively, the actual site model may be created by traversing the site with the, ~p~tin~ machine itself or through the use of special r-^h ~ nPry and/or vehicles which are suited to the conditions.
3rief Descri~tign o~ the I~awin~TR
FIGURE 1 is a schematic , t~ s~:nLation of a compacting l-~^h; nPry position and control method Pr-cnr~lln~ to the present invention;
FIGURE 2 is a schematic reprPRPntPtion Df an apparatus which can be used in cnnnPct; on with the receipt and processing of GPS signals to carry out the present invention;
FIGURE 3 is a detailed schematic representation of an embodiment of the system of Figure 2 using GPS positioning;
FIGURE 4 is a schematic representation of a work site, ~ ~ctin~ machine, and position and control system according to an illustrative compacting : ' -'; -t of the present invention;
FIG~RES 5A-5B are graphic reproductions of exemplary topographical land~ill site modPls such as used with the present invention;

WO 95/16227 PC r/uss~ll2733 2~ S333 F I GURES 6A- 6B are reprP q~n ~ = ~ i ve real - time operator displays generated according to the present invention for a landfill compacting operation;
FIGURES 7A-7I are flowchart representations s of a dynamic site databasa according to the present invention;
FIGUR13 8 is a schematic representation of the system of the present invention including a closed-loop automatic machine control system.
Det~iled Descri~tion of the Illugtrated Embo(1i--n~q Referring to Figure 1, the method of the present invention for uae in a compacting operation is shown schematically. Using a known three~ n~l positioning system wlth an external reference, for example (but not limited to) 3-D laser, GPS, GPS/laser co~mbinations or radar, compacting machine position coordinates are determined in block 100 as the machine moves over the site. These coordinates are instantaneously supplied as a aeries of discrete points to a differencing algorithm at 102. The differencing algorithm calculates the machine position and path in real time. Digitized models of the actual and desired degree of compaction of the site topography are loaded or stored at block 104, an acceqsible digital storage and retrieval facility, for example a local digital computer. The differencing algorithm 102 retrieves, m-nir~ q and updates the site models from 104 and generates at 106 a dynamic site database of the difference }~etween the actual site and the desired site model, updating the actual site model in real-time as new position information is receiYed from block 100. This dynamically updated site model is then made available to the operator in display step 108, providing real time position, Wo 95/16227 PC'r/U594/12733 direction and site topography/compaction updates in human readable form. Using the information from the display the operator can efficiently monitor and direct the manual control of the compacting machine at l09.
Additionally, or-alternately, the dynamic update inf ormation can be provided to an automatic machine control eyatem at ll0, for example an electrohydraulic control system of the type developed by Caterpillar Inc. and used to operate the various pumps, valves, hydraulic cylinders, motor/steering merhi~n; ~mc and other controls used in compacting r-~-hin~ry The electrohydraulic controls can provide an operator assist to min;mi7,o machine work and limit the manual controls if the operator' s proposed action would, for example, overload the machine.
Alternately, the site update information from the dynamic database can be used to provide fully automatic control of one or more machine operating systems.
It will be clear from the foregoing that with the present method a model of the initial, actual site topography can be gPnf~ ci by the m1 ct i n~
machine itself on previously unsurveyed terrain. By simply moving the machine over a proposed site in a regular pattern, the current topography can be rmi n~d . Once the initial topography of the ~ite is establi3hed as an initial three-~ n~l reference, actual and desired 6ite models can be loaded at 104. The desired site model is a prede~-~mi nf.ri desired degree of compaction of material on the site surface. The actual site model is the actual degree of compaction of the site material, ranging between an uncompacted state and the desired degree of compaction. When the machine traversee the WO 9S/16227 PCTIUS9~/12733 2~ 5339 -~2- ~
5ite in a compacting operation, the actual 6ite model i3 monitored and updated ir real time at 106 as the machine brings the actual site into conformity with the desired site model.
Referring now to Figure 2, an apparatus which can be used in rnnnf-~-t; nn with the receipt and processing of GPS signals to carry out the present ~,-ting invention is shown in block diagram form comprising a- GPS receiver apparatus 120 with a local reference antenna and a satellite antenna; a digital proce8sor 124 employing a differencing algorithm, and connected to receive position signals rom li!0; a digital storage and retrieval facility 126 accessed and updated by processor 124, and an operator display and/or automatic machine controls at 12a receiving signals from processor 124.
GPS receiver 8ystem 120 includes a satellite antenna receiving signal3 from global positioning satellite8, and a local reference antenna. The GPS
receiver system 120 uses position signals from the satellite antenna and differential correction 8ignals from the local reference antenna to generate position coordinate data in three-dimensions to centimeter accuracy for moving objects. Alternatively, raw data from the reference antenna can be transmitted to processor 124, where the differential correction can be locally determined.
Thi8 position information is supplied to digital processor 124 on a real-time basis as the coordinate _ 1 ;n~ rate of the GPS receiver 120 permits. The digital storage facility 126 8tores a f irst 8ite model of the desired degree of compaction of the site, ~or example according to a pr~lf.t~rrn;nf~r:L
-t;on gtandard, and a second site model of the actual degree of compaction of the 8ite, for example O~Wo 95116227 7~3g PCT/US94~12733 uncompacted as initially surveyed. The actual site model can be accessed and updated in real time by digital proces60r 124 as it receives new position information from GPS receiver 120.
Digital processor 124 further generates signals representing the difference between the continuously-updated actual site model and the desired site model. These signals are provided to the operator display and/or automatic machine controls at 128 to direct the operation of the machine over the site to bring the updated actual site model into conformity with the desired site model. The operator ~ - -display at 128, for example, provides one or more visual representations of the difference between the actual site model and the desired site model to guide the operator in running the machine for the necessary , ?c~t; n~ operations .
Ref erring now to Figure 3, a more detailed schematic of a system according to Figure 2 is shown using k;r t;C GPS for position reference signals. A
base reference module 40 and a position module 50 together determine the three-dimensional coordinates of the compacting machine relative to the site, while an update/ control module 60 converts this position information into real time representations of the site which can be used to accurately monitor and control the machine.
3ase reference module 40 includes a stationary GPS receiver 16; a computer 42 receiving 3 0 input f rom receiver 16; ref erence receiver GPS
sof tware 44, temporarily or permanently stored in the computer 42; a standard computer monitor screen 46;
and a digital transceiver-type radio 48 connected to the computer and capable of transmitting a digital data stream. In the illustrative ~mho~ir base W0 95/~6227 3 9 PCTIUS9~/12733 reference receiver 16 is a high accuracy kinematic GPS
receiver; computer 42 for example is a 4a6DX computer with a hard drive, 8 megabyte RAM, two serial ~- i r~ tion portg, a printer port, an external monitor port, and an external keyboard port; monitor screen 46 is a pas~rive matrix color LCD; and radio 48 iG a commercially available digitaI data transceiver.
Position module 50 comprises a matching kinematic GPS r~ceiver 18, a matching computer 52 receiving input from receiver 18, kin tir GPS
software 54 stored permanently or temporarily in computer 52, a standard computer monitor screen 56, and a ---trhin~ transceiver-type digital radio 58 which receives signals from radio 48 in base reference module 40. In the illustrative ' - 'i position module 50 is located on the compacting machine to move with it over the work site.
Update/control module 60, also carried on board the compacting machine in the illustrated ~ml~nrl;- ~, includes an additional computer 62, receiving input from position module 50; one or more site models 64 digitally stored or loaded into the computer memory; a dynamic database update module 66, also stored or loaded into the memory of computer 62;
and a color operator display screen 22 connected to the computer. Instead of, or in addition to, operator display 22, Alltl tic machine controls 70 can be connected to the computer to receive signals which operate the machine in an automatic or semi-automatic 3 0 manner in known f ashion .
Although update/control module 60 is here shown mounted on the compacting machine, Gome or all portions may be stAt;rn~ remotely. For example, computer 62, site model(s) 64, and dynamic database 66 could be connected by Fadio data link to position Wo 95/16227 PCTfUSs~fl2733 1 7s33~ -15-module ~0 and operator display 22 or machine control interface 70. Position and site update information can then be broadcast to and from the machine for di3play or use by operators or supervisors both on and 5 of f the machine .
Base reference atation 40 is fixed at a point of known three-dimensional coordinates relative to the work site. Through receiver 16 base rP~PrPn~e station 40 receives position information from a GPS
satellite constellation, using the reference GPS
software 44 to derive an instAntAnf~ c error quantity or correction f actor in known manner . This correction factor is hroArlrAct from base station 40 to position station 50 on the compacting machine via radio link 48, 58 . Alternatively, raw position data can be transmitted from base station 40 to position station 50 via radio link 48,58, and processed by computer 52.
Machine-mounted receiver 18 receives position information from the satellite const,~ tinn, while the kinematic GPS software 54 combines the signal ~rom receiver 18 and the correction factor i~rom base reference 40 to determine the position of receiver 18 and the compacting machine relative to base reference 40 and the work site within a few centimeters. This position information is three-dimensional (e.g., latitude, longitude and elevation) and is available on a point-by-point basis according to the E-mrl ;n~ rate of the GPS system.
Referring to update/control module 60, once the A;s;ti7F~ plans or models of the site have been loaded into computer 62, dynamic database 66 generates signals reE~resentative o~ the di~erence between the actual and desired degree of ~ _ A~-t; nn of the site to display this di~f erence graphically on operator display screen 22 relative to the sit~ topography.

Wo 95/16227 2 17 5 3 3 9 PCT/U594112733 Using the pos~tion information received from position module 5Q, the database 66 also generates a graphic icon of the compacting machine superimposed on the site topography on display 22 corresponding to the actual position and direction of the machine on the site Because the sampling rate of the position module 50 results in a time/distance delay between position coordinate points as the compacting machine moves over the site, the dynamic database 66 of the present invention use~ a differencing al~orithm to fl,~tPrm; nP and update in real -time the path of the machine With the knowledge of the compacting lri machine' 8 exact position relative to the site, the degree oi compaction of the site, and the machine~ 8 progress relative thereto, the operator can maneuver the compacting machine over the site to compact it without having to rely on intuitive feel, memory or physical site markers. And, as the operator moves the machine over the site the dynamic fl~t~ e 66 ~nt;n11e~ to read and manipulate incoming position information from module 50 to dyn~m~ y update both the machine's position relative to the site, the path of the machine over the site, and any change in degree of compaction effected by the machine's passage. This updated information is used to generate representations of the site and can be used to direct the operation of the compacting machine in real time 3 0 to bring the actual, updated site model into conformity with the desired site model.
Tnfl1l~tri~l A~licabili~v Ref erring to Figure ~, a compacting machine lO is shown on location at a construction site ~2. In ,~WO 95/16227 7S33g 1., ~ PCT/US94112733 the illustrative ~ of Figure 4 machine 10 i8 a wheeled landfill compactor It will become apparent, however, that the principles and applications of the present invention will lend themselves to virtually any compacting machine with the capacity to move over and compact material on the site .
Compactor 10 is equipped in known fashion with available hydraulic or electrohydraulic controls (not shown). In the embodiment of Figure 4 these controls operate, for example, steering and motor controls. t' ,~ tr~r 10 includes two spaced front wheels 26 which can be turned to control the direction of the compactor, and two spaced rear wheels 28 which are :Eixed relative to the body or frame of compactor 10. The compactor wheels 26,28 have wide, studded surfaces capable of compacting waste and trash in a landfill in known fashion. ~ompactor 10 is heavy, and may be weighted to increa6e the compacting force exerted by the wheels on the material which they traverse .
Machine 10 is equipped with a positioning system capable of determining the position of the machine and/or its, , ~tin~ wheels with a high degree of accuracy, in the ' - ~;~ - of Figure 4 a phase differential GPS receiver 18 located on the machine at fixed, known coordinates relative to the site-contacting portions or "footprints" of the wheels. Machine-mounted receiver 18 receives position signals from a GPS constellation 14 and an error/correction signal from base reference 16 via radio link 48,58 as described in Figure 3. Machine-mounted receiver 18 uses both the satellite signals and the error/ correction signal from base reference 16 to accurately determine its positi_n in three-Wo 95/16227 2 1~ 5 3 3 9 PCTIUS94/12733 ~
--1 8--.
dimen3ional space. Alternatively, raw position data can be transmitted from base reference 16, and processed in known f ashion by the machine -mounted receiver system to achieve the same- result .
Information on kinematic GPS and a system suitable for use with the present invention can be found, for example, in U.S. Patent No. 4,812,991 dated 14 March 1989 and IJ.S. Patent ~o. 4,963,889 dated 16 October 1990, both to Hatch. Using kinematic GPS or other suitable three-dimensional position signals from an external reference, the location of receiver 18 and compactor 10 can be accurately ~1Pt~m;n.~1 on a point-by-point basis within a few centimeters as compactor 10 moves over site 12. The present sampling rate for coordinate points using the illustrative positioning sy6tem is approximately one point per second.
~he coordinates of base receiver 16 can be det~in.o~ in any known fashion, such as GPS
positioning or conventional surveying. Steps are also being taken in this and other countries to place GPS
references at fixed, nationally surveyed sites such as airports. If site 12 is within range (currently approximately 20 miles) of such a n~ nAl l y surveyed site and local GPS receiver, that local receiver can be used as a base reference. Optionally, a portable receiver such as 16, having a tripod-mounted GPS
receiver, and a rebroadcast transmitter can be used.
The portable receiver 16 is surveyed in place at or near site 12 as previously discussed.
Also shown in schematic form on the E-rtor 10 cf ~igure 4 is an on-board digital computer 20 including a dynamic database and a color graphic operator display 22. Computer 20 is connected to receiver 18 to continuously receive compactor position information. Although it is not ~ ,c~ry to Wo 95/16227 ~ ^ PCT/US94/12733 place computer 20, the dynamic database and the operator display on compactor 10, this is currently a preferred ~ t and simplif ies illustration .
In the illustrated ~-~n~l; t of Figure 4, 5 the machine-mounted position receiver 18 is positioned on the cab of compactor 10 at a fixed, known distance from the ground-engaging portions or "footprints" of the compactor wheels. Since the wheels are actually in contact with the site topography, receiver 18 is calibrated to take this elevational difference into account; in ef f ect, the cab-mounted receiver 18 is perceived by the system as being level with the site topography over which the compactor is orerating.
While the uc~e of a single position receiver 18 at a fixed distance from the compactor's site-contacting wheels i8 an effective and sturdy ~ nt;n~
aLL~-~y~ nt, in certain applications it may be preferable to use different mounting aLLc.-ly~ ~ for the positioning receiver. For example, the current direction of the compactor relative to the site plan, ac~ nhown on di~play 22 by icon 82 and direction indicator 84 in Figure 6A, may be off by a slight time lag vector, ~ r~n~l;n~ on the sampling rate of the receiver 18 and the machine' 8 rate of directional change. With only one position receiver 18 mounted on tractor 10, machine direction at a single point cannot be determined since the machine ef ~ectively pivot6 around the single receiver. This problem is solved by placing a second position receiver on the machine, spaced from the first, for a directional reference point .
Additionally, the lengthwise distance between the wheels 26,28 and the cab-mounted GPS
receiver 18 in ~igure 4 çreates a slight real time offset in resolving the position of the wheels as they WO 95/16227 rCTlUS9~112733 rl5339 `
~ -20 -compact the site. In most cases this delay is negligible, since the GPS position closely precedes or follows the wheels and essentially matches the rr~rt;ng operation. On larger ~rh;n~q, however, it may be preferable to mount one or more position receivers 18a directly in line with one or more of the wheels as shown in Figure 4 in phantom.
Referring to Figures 5A-5B, an illustrative landfill site has previously been surveyed to provide a ~lrt~ d topographic blueprint ~not shown) showing the initial landf ill topography in plan view . The creation of topographic blueprints of sites such as landf ills and construction sites with optical ~qurveying and other techni1r~ues is a well-known art;
reference points are plotted on a grid over the site, and then connected or f illed in to produce the site contours on the blueprint. The greater the number of ref erence points taken, the greater the detail of the map.
Systems and software are currently available to produce digitized, two- or three-dimensional maps of a topographic site. For example, the topographic blueprint can be converted into a three-dimensional digitized model of the initially surveyed landfill topography as shown at 36 in Figure 5A and o~ a subsequent site topography, for example after the l;ln~l~;ll has been substantially filled in, as 3hown at 3 8 in Figure 5B . The site contours can be overlaid with a reference grid of uniform grid elements 37 in known fashion. The digitized site plans can be superimposed, viewed in two or three ~l; ci rnq from various angles (e.g., plan or profile), and color coded to ~q;r~n~t.~ areas in which the site needs to be ~illed in or compacted.

~Wo95/16227 7S33~ PCI/US94/12733 However the site is surveyed, and whether the machine operators and their supervisors are working from a paper blueprint or a digitized site plan, the prior practice is to simply add material to the landf ill and monitor the compacting operation by feel, memory and/or physical markers. Periodically during this process the operator' 8 progress may be manually checked to coordinate the, ~ -~t; n~
operations in static, step-by-step fashion until uniform, satisfactory compaction is achieved. This manual periodic updating and rhPrk; nr is labor- =~:
intensive, time cr~n~l~minr~, and inherently provides less than ideal results.
Moreover, when it is desired to revise the blueprint or digitized site model as an indicator of ~IL~_JyLeS::I to date and work to go, the site must again be statically surveyed and the blueprint or digitized site model manually corrected off-site in a non-real time manner.
To Pl ;min~te the drawbacks of prior art monitoring and static surveying and ~lrrlRtln~ methods, the present invention integrates accurate three-dimensional positioning and digitized site mapping with a dynamically updated database and operator display for real-time monitoring and control of the site 12 and compactor 10. The dynamic site ~l~tAh~e determines the difference between the actual and desired site models in terms of degree of compaction of the site topography, receiveg ki~ tic GPS
position information for compactor 10 relative to site 12 from position receiver 18, displays both the site model and the current machine position to the operator on display 22, and updates the actual site model, machine position and display in real time with a degree o~ accuracy measured in centimeters. The Wo 95/162Z7 PCrrUS9Vl2733 217~339 ~

operator accordingly achieves unprecedented knowledge of and co~trol over the fl, ftin~ operations in real time, on-site, and can accordingly finish the job with virtually no interruption or need to check or re-burvey the site.
Referring now to Flgures 6A-6B and 7A-7I, an application of the present invention is illustrated for a landfill ~ t;n~ operation.
In machine, ,~A~-t;n~, for example of landfills, earth, or freshly laid asphalt, the completion of the compacting operation i6 typically a function of the number of passes of the compactor over the surf ace to be compacted . The desired degree o compaction can be determined, for example, by running a compactor over a test area of uncompacted material and empirically detfrrn;n;n~ a suitable pass-count standard. 3y way of illustrative example, in a landfill compacting operation it iB desirable that a machine such as a large, heavy compactor with studded rollers or wheels pass over a portion of the 1 ~n~
to compress new refuse to some predetermined degree in accordance with local compaction regulations or sound 3rt; ng practiceg . It is therefore important or the operator of the, , If tfr to know: whether he has been over a given unit area or grid element of the landfill site; how many times the compactor has been over a given grid element on the site; the extent to which the material has been gucceggfully ~_~ -ftP~1 within a grid element on the site; and, whether l~nf a~-ted material has been added to a particular grid element since the last compacting pass.
At the start o the compacting operation, the actual site model may initially comprise a three-dimensional survey or map of the site topography in an 35 , -~ ;3rted state, for example the digitized three-~W0 95~16227 3~ , PCT/US94112733 dimenæional cite model of Figure 5A for a landfill application. As ~rt; n~ operations progress, the = .
actual site model more specifically comprises the actual degree of compaction of the material on the surface of the site, as measured for example by compaction pas9 count and/or elevation change. The actual site model is dynamic in that it changes each time new material is added or old material is further compacted from its previous state.
The desired site model comprises a predetermined, desired degree of compaction for material on the surface of the site. For example, where the desired degree of compaction is predetermined to be a total of f ive passes of the compactor over a previously uncompacted area, the desired site model is a pass count of five passes over a previously 1lnl , ~rted area. When that pass count is reached, the desired site model is achieved. The difference between the actual and desired site models at any point on the site comprises the difference ~etween the actual degree of compaction and the desired degree of compaction at that point.
The actual site model accordingly fluctuates between an lln~ ted state of the site material and the desired degree of ,~ct;on. Whenever new, ullC ~-te~l material is detected in a previously compacted area of the site, the actual site model returns or de.:,~ tc to an l~n~ ~CtP~ gtate for that area .
Using the method and apparatus of the present invention, all of this information can be determined and updated in real time, with a great degree of accuracy and with a user-friendly display f or the operator .

Wo 95/16227 PCr/llS9~112733 21~339 ~ ----24-- ' Figure 6A shows a aample operator display 22 for a compacting operation according to the present invention. Using a digitized model of the 1 An~f; ~1 site with a superimposed set of grid elements, and a compactor e~uipped with position module 50 and update/control module 60 in Figure 3, the operator first initializes the operator display 22, typically upon entering the landfill site. In landfill ,ar~t;n~ the probable activity field for a day is typically small, on the order of a few hundrea~or thousand square meters. For purpose3 of illustration in Figure 6A the site database is arbitrarily set at approximately 30 meters by 40 meters. This can be varied depending on the nature of the particular compacting operation. This i8 smaller than the total area of a typical landfill, but for a single day the compactor operator needs a database only for the portion of the landfill in which he will be operating.
In a large land~iIl application, individual site databases can be parceled out to each operator at the beginning of a day, the updated ~IAtAhAR~R for each portion o the lAnrlf;ll gathered at the end of the day and recorrelated relative to the overall landfill for the next day' s work .
In the illustrated ~ the system arbitrarily assumes upon ntart up and initialization that the compactor is in the center of the site, divided into a grid of squares of fixed area, e.g., one square meter. The operator can center the ~ , ctor with respect to the designated site either by driving to a designated central marker, or using GPS or similar positioning techniques.
Once_ arrived at the center of the site, the operator initializes the display and is presented on screen 22 with a site database in plan window 70 such 0 95/16227 PCT/[IS94/12733 ~W ~
as that shown in Figure 6A, marked off in a grid pattern of elements 71 initially all one color; e.g., black to indicate that no passes have yet been made over that site. A E-os; t; nn coordinate window 72 displays the I , rtnr~s current position in latitude, longitude, elevation and time. A menu window 73 displays zoom options in the display software which allow the operator to expand or contract the amount of the site ~displayed in plan window 70. The compactor position is denoted by an icon 82 with direction indicator 84.
Prior to the ~ ;nn;n~ of work on the site, a compaction standard (here a pass count) is set to denote the desired degree of, ~ ~ntinn of the site .
For example, it may be determined that five passes of the compactor over l~n~ ted material on any one grid element are necessary for that grid element to be adequately compacted. As the operator traverses the site, each pass of the compactor wheels over a grid element will result in a database update in real-time.
The ~rid elements oi the site display can be visually updated in a variety of ways to show the difference between the actual and desired degree of compaction, e.g., shading, cross-h~t~-h;n~, coloring or "painting"
(where a color display is used), or in any other known manner to provide an indicator to the operator of the compaction status of the grid ~l ~ s . In the illustrated ~ i t of Figure 6A the grid changes color to denote the actual degree of , , -~-t; nn in terms of how many passes have been made; e.g., the darkest to lightest shading o~ grid elements 71 represent black for no passes, yellow for one pass, green for two passes, red for three passes, blue for four passes, and white ;nrl;~t;ns satisfactory 35 compaction at five passes. The objective is to make Wo 95/16227 PCT/US9iJ/12733 21~ ~339 -26-the entire screen white as the operator display is updated in real-time to in~inatp the number of pas3es over each grid element.
As an additional aid to the operator, the approximate path of the compactor as measured by coordinate samples can be shown on display 22, in Figure 6A denoted by a series of dots 83 where each position reading was taken.
Figure 6B is one possible alternate display in which the two-dimensional plan view of the site and compactor po3ition of Figure 6A is shown in three dimensions in window 70.
It i8 necessary to provide some protocol for determining when a suf f icient portion of a grid element has been passed over by a compactor wheel to warrant a status update for that grid element and register a ~ , ~nt;n~ pass on the operator display.
For the illustrated compactor with two or more spaced compacting wheels, the following illustrative method can be used. The size of each grid element on the digitized site plan is preferably matched to the width of a ~ ,-~tin~ wheel; e.g., for one meter wide wheels the grid elements should be set to one square meter.
Accordingly, if the center of the wheel crosses a grid element at any point, it is assumed that at least one half of the grid element has been compacted and can be updated on the display. These dimensions and margins can be varied as desired, however.
The coordinates of the ground-contacting surfaces (~footprintsn) of the fixed rear compactor wheels are known relative to the position receiver on the, _ ntnr. Each coordinate sampling by the positioning system can accordingly be used to ~lPt~rm1 nP the precise location of the center of each wheel at that point.

~Wo 95/16227 2~ PCTIUS94/12733 In the illu3trated embodiment the positions of the f ootprints of the rear compactor wheels are tracked, since in a typical compactor the rear compacting wheels are fixed relative to the cab and position receiver 18. I~ L~V~L~ compactors often operate in a substantially linear, back and forth manner cver the site, without sharp turns which would tend to disturb previou31y compacted material. The paths of the evenly-spaced front and rear wheels essentially overlap, such that the compacting path of the front wheels can be accurately estimated by the paths of the f ixed rear wheels .
The time lag between coordinate samplings as the compactor wheels travel over several grid Pl ~ t~
must also be taken into consideration to accurately determine the entire real-time path of the compactor.
In a compactor with compacting wheels whose width apprn~ tP~ the width of the site model grid elements, a preferred method shown in the illustrated embodiment of the present invention uses the well-known ~3resenham' 8 algorithm to produce a continuous line approximating the path of each compactor wheel over the grid elements between coordinate samplings.
Then, if the sampling rate only provides a coordinate ~point~ every three or four grid elements, a line approximation is made of the compactor wheel paths over those three or four grid elements (corrpspnn~l; n~
to the center of the wheels), and every grid element along that line is given a status update and visual change on the operator display.
Referring to Figure 7A, the method of the present invention as applied to a landfill compacting application is schematically shown. At step 500 the operator starts f rom the computer operating system.
At step 502 database memory is allocated and ::
Wo 95116227 PC rlUS94/12733 21~533~ ~

initialized. At step 504 the various displays are initialized. In step 506 the serial communications port between the positioning module and update/control '--module is initialized. At 3tep 508 the system determines whether there has been an operator request to terminate the program, for example from a u3er ; ntPrfA~e device such as a computer keyboard . This option is available to the operator at any time, and if the system determines that such a request to terminate has been received, it proceeds to step 592 and stores the current site database in a file on a suitable memory device, _or example a disk At steps 594, 596 the operator is returned to the computer operating system.
If, however, the system tli-t~rm;n~R at step 508 that there has not been a request to terminate the program, it proceeds to step 510 where a position coordinate is read from the gerial port cnnnf.~t;nn between the position module 50 and update/control module 60 of Figure 3, in the illustrated embodiment a three-dimensional GPS-determined coordinate point. At step 512 the position of the ~ - tnr is displayed (Figure 6A) in window 72 on operator disE)lay screen 22 as three-dimensional coordinates relative to base reference 16.
For the f irst system loop at step 514 the position of the . _ rtnr is initially displayed on the operator screen 22 as icon 82 in the middle of the plan display 70. In the illustrated embodiment of Figure 6A the site database displayed at 70 is approximately 30 x 40 meters, the ~ ~ ctnr has two separate rear compacting wheels, each wheel one meter wide, and the grid element size i8 fixed at one square meter .

WO 95/16227 ~S3 PCT/US94/12733 9 . ~ .

In step 514 a subroutine shown in Figures ---7B-7C draws the displays and icon, determines the orientation of the compactor and the position of the centers of the "footprints" or ground-contacting portions of the rear, ~t~lr wheels, tracks the path of the rear compactor wheels over the site database, and updates the compaction status of the grid elements in the path of the compactor.
Reerring to Figure 7B, at step 516 the system determines whether the first program loop has been ~er~1t~-1. If not, the site database and display window coordinate systems are initialized and displayed on operator screen 22 at step 518. After the first program loop has been executed and the site database initi~l;7~d and displayed on the operator screen, the system at step 520 checks whether icon 82 has already been drawn. If yes, the previous icon 82 is erased rom the display at step 522. If the icon has not yet been drawn, at step 524 the system det~nT;n~R whether the first loop has been ~YF~c~lt~
if not, the or;-~ntAt;r~n of the compactor is initialized at step 526 and the system completes the overall program loop of Figure 7A. If at step 524 the system determines that the f irst loop has already been Pln~-l1t~1, the system proceeds in Figure 7B to step 528 to ~let~rm;n,o whether the ~ rt~lr hag moved since the last program loop. If the machine has not moved, the system exits the subroutine of Figure 7B and returns to complete the overall program loop of Figure 7A from step 514.
If the machine has moved relative to the site ~t~h~e since the last loop, the system proceeds to step 530 in Figure 7B to calculate the positions of the centers of the footprints o~ the rear compactor wheels, and rom those the or;/~ntAt;~n of the Wo 95/16227 PCr/US9-1112733 217~33~ -30-compactor At step 532 ln Figure 7C the system determines whether the right rear ~ ra~~t~r wheel position has moved out of the grid element it occupied during the last position measurement. If it has, at step 534 the path of the right wheel between the previous and current coordinate samplings i8 determined using the well-known Bresenham' s algorithm to approximate a continuous line path of the right wheel over the grid elements on the display 22. The grid elements o~ the site database over which the right wheel has passed are then updated to indicate a compaction pass, and grid elements are updated on the visual display window 70 with a color change or other visual indicator.
If at step 532 the right whee~ has not moved since the last position measurement, or after the Illuv. t of the right wheel has been tracked and the site database updated at step 534, the process is repeated for the left wheel of the compactor at steps 536, 538 . At step 591 the updated compactor icon is then redrawn on the display to show its current position and direction. The subroutine of step 514 in Figure 9 is then completed, and the system returns to repeat the program loop of Figure 7A, either proceeding to step 510 for another GPS coordinate r3ampling, or terminating in response to an operator request .
In Figure 7D a Eiubroutine for the wheel tracking and site updating operations of steps 534 and 538 is shown At step 540 the starting and ending grid cells for the wheel whose path is being determined are defined by the current wheel position mea~ul and the previous wheel position mea~ . t taken by the GPS or other positioning system. The Bresenham' s algorithm is applied to ~Wo 9~116227 ~533~ - 3 l - PCT/US94112733 determine the grid cell6 located along the path between the starting and ending grid cells, and the system proceeds to steps 544,546,548 to evaluate/update the status of each grid element therebetween, hF~;nning with the fir3t grid element a$ter the starting grid element. At step 542 the system determines whether the ending grid element has been evaluated; if not, it proceeds to step 544 where the grid element being evaluated i5 updated according to a subroutine in Figure 7E. Once the compaction status of the current grid element has been updated at step 544, the updated grid element is displayed on the operator screen 22 at step 546, and at step 548 the system is in~, o~1 to evaluate the next grid element in the path between the starting and ending grid ~1 t~, This loop repeats itself until the ending grid element has been evaluated and updated, at which point the subroutine of Figure 7D is exited and the program returns to step 591 in Figure 7C to draw the updated, , ~t~r icon on the display.
n Figure 7E the subroutine ~or the site ~lAtAhAç~e update step 544 of Figure 7D is shown.
Referring to Figure 7E, at step 550 the system determines whether the elevation of the current grid element has been initialized. If not, the elevation or z-axis coordinate of that grid element is ;n;tiAl i7~.:1 as equal to the currently measured compactor wheel elevation at that point. If the grid element elevation has already been initialized, the system proceeds to step 554 to compare the currently measured wheel elevation to the previously measured elevation for that grid element. If the currently measured wheel elevation on that grid element is not greater than the previously measured elevation, the system determines that no new material has been added Wo 95/16227 PCrlUS9~112733 and that grid element can be incremented at step 558 to register a compaction pass and increment the pass count for that grid element. If at step 554 the currently measured wheel elevation is greater than the previously measured elevation Idiscounting, for example, minor resilient expansion of the material compressed in the last pass, within limits determined by the user) the system determines at step 556 that a new lift of asphalt, earth or waste material has been 0 ~l~tPr~t~l~ for that grid element, and the~pass count status for that grid element is re-zeroed to indicate the need for a complete new series of compaction passes. At step 560 the elevation of the current grid element is then set equal to the currently measured elevation of the compactor wheel for comparison at step 554 on the next pass of the compactor over that grid element. The subroutine of Figure 7E is then exited for completion of the subroutine loop Qf Pigure 7D .
Referring now to Pigures 7P-7~, a subroutine for step 546 of Pigure 7D is shown Once the pass count for the current grid element has been updated at step 544 in Figure 7D using the subroutlne of Pigure 7E, the system in 3tep 546 enters the subroutine of Figures 7F-7C: and at step 562 first determine3 the location and size of the current grid element on the site database displayed in plan window 70 on the operator screen 22. At step 564, if the pass count f or the grid element is zero, the grid element is set, for example, to be colored black on the display at step 566. If the pass count for that grid element is det~rm;nf~ to be one at step 568, the grid element is set, for example, to be colored yellow on the display at step 570. If the pass count for that grid element is determined at step 572 to be two, the grid element ~ Wo 95/16227 7S339 is 3et, for example, to be colored green at step 574.
If the pas3 count i8 determined at 3tep 576 to be three, the grid element i3 set, for example, to be colored red at 3tep 578. If the pa33 count for that - 5 grid element i3 detl~rm;nP~l at 3tep 580 to be four, the grid element i3 3et, for example, to be colored blue at 3tep 582. If the pa33 count i3 determined at 3tep 584 to be five (in the illu3trated embodiment the de3ired pa33 count for a completed compacting operation), the grid i3 3et, for example, to be colored white at step 586. If the pa33 count for that area i3 greater than the minlmum pa33 count for a completed compaction operation, the grid element i3 3et to be colored white at 3tep 588.
Once the grid element ha3 been updated according to the current pa33 count, the grid element i3 drawn and colored on the operator di3play 3creen 22 at 3tep 590. It will be under3tood that the grid element3 can be vi3ually updated on 3creen 22 other than by coloring; e .g., by cro3s-h~trh; ng, shading or other vi3ual indication.
While the tracking and updating method of Figure3 7A-7G are illu3trated for a compactor having two or more 3paced ,~rt;nr wheel3 who3e width apprr,7r;r~-t~ the width of the 3ite grid ,~l~ tR, the method can al30 be u3ed for a ~ rtrr with a 3ingle wheel or roller a3 will be understood by tho3e 3killed in the art. The method of Figure3 7A-7G can al30 be u3ed where the width of the compactor wheel or roller doe3 not match the width of the grid element3 of the 3ite model. However, where the width of the compacting wheel or roller i3 sirnif;r~ntly greater than the width of a single grid element, for example where it sover3 several grid element3 at one time, an Wo 95/16227 , ~ PCI/IJS9~/12733 1 21~533~ ~
alternate method for tracking the path of a compacting wheel or roller may be employed.
This is accompliahed by replacing step 530 in Figure 7B with step 530' from Figure 7H, and the s subroutine of Figure 7D with the subroutine of Figure 7I. Referring to step 530' in Figure 7H, the system designates "effectiue~ wheel or roller ends inboard from the actual ends. In the illustrated embodiment the effective ends are r~n~n;7~ l by the differencing algorithm as inboard from the actual end a distance approximately one half the width of a grid element.
For example, if the actual wheel width is 5.0 feet, corresponding to five 1.0 foot x 1.0 foot grid elements, the effective locations of the wheel ends can be calculated, for example, one half foot inboard from each actual end. If the effective ~non-actual) wheel ends of the compactor pass over any portion of a grid element on the digitized site model, that grid element is read and manipulated by the dif f erencing algorithm as having been compacted, since in actuality at least one half of that grid element was actually passed over by the wheel. Of course, the amount of wheel end offset can vary t3-~r.onrl;n~ on the size of the grid elements and the desired margin of error in determining whether the wheel has passed over a grid element .
While the algorithm of step 530 ' in Figure 7H, _ ~tes for the lack of complete corre~pondence between the width of the compacting wheel or roller and the r~umber of grid elements completely traversed by the wheel or roller, the distance and direction changes which the wheel makes between GPS position readings results in a 1088 of real time update information over a portion of the, ~,r~ 8 travel .
35 This is particularly acute where, _--t~r travel I~.~o 95116227 339 PCTIUS94112733 speed is high relative to the grid Pl ~ -nt~ of the site plan. For example, where the grid elements are one meter square and the ~;~r~l ;nr~ rate of the position system is one coordinate sample per second, a machine traveling at 18 km per hour travels approximately f ive meters or f ive grid squares between position samplings. Accordingly, there is no real time information with respect to at least the inte" ~; AtP
three of the f ive grid squares covered by the machine .
rrO solve this problem a "fill in the polygon"
algorithm as shown in Figure 7I is used to estimate the path tLav~-L~ed by the machine between coordinate l ;nr~s . In Figure 7I the algorithm at step 540' locates a rectangle on the site plan grid surface defined by the effective ends of the compactor wheel at positions (xl, Y1) and (x2, Y2) and coordinate position (x~, y~). At steps 542', 543' and 548' a search algorithm searches within the rectangle ' s borders for those grid elements within a polygon defined between the two wheel pQs;t;nn~; i.e., those grid elements traversed by the wheel between its ef ective ends .
At steps 544 ' and 546 ' the database and display are updated as described at steps 544 and 546, respectively, in Figures 7D-7F.
While the illustrated ~Q~i t of a compacting application of the present invention is a pass-count based system, it will be apparent that other update protocols can be employed. For example, the change in amount o~ ~-ct;nn per pass over a grid element can be determined by rhPrk; n~ the elevation change since the last pass, and when the change in elevation on a particular pass is below a certain value (;nr~;r:lt;nr~ that the garbage is near the desired compaction density), that grid element is Wo 951162~7 2 17 5 3 3 ~ PCTIIJS94/12733 ~, updated on the scr~en as completed.~ Another method is to use an absolute compaction standard, registering a particular grid element as finished when the material thereo~ has been compacted f rom an uncompacted or initial elevation to a predetermined lower elevation.
Referring now to Figure 8, an alternate system according to the present invention is schematically shown for closed-loop automatic control of one or more operating systems on the compactor.
While the: ' - 'i t of Figure 8 is capable of u3e with or without a supplemental operator display as described above, for purposes of this illustration only automatic machine controls are shown. A suitable digital processing facility, for example a computer as described in the foregoing: '~n~; tF~, containing the algorithms of the dynamic database of the invention is shown at 400. The dynamic database 400 receives 3-D
instantaneous position information from GPS receiver system 410. The desired site model 420 is loaded or 20 stored in the database of computer 400 in any suitable manner, for example on a suitable disk memory.
t~ tir machine control module 470 contains electrohydraulic machine controls 472 connected to operate, for example, steering and drive systems 474,476,478 on the compacting machine. Automatic machine controls 472 are capable of receiving signals from the dynamic database in computer 400 representing the difference between the actual site model 430 and the desired site model 420 to operate the steering and drive systems of the compactor to traverse the site in a manner to bring the actual site model into coIIf ormity with the desired site model . As the automatic machine controls 472 operate the steering and drive systems of the machine, the ' ~ ct i nn of the site and the current position and direction of the 9S/16227 39 37_ pcrlUS94/12733 compactor are receved, read and manipulated by the dynamic database at 400 to update the actual site model. The actual site update information i9 received by r~AtAh~e 400, which corr~rnn-9~nsly updates the ~; signals delivered to machine controls 472 for operation of the steerng and drive systems of the compactor as it makes compacting passes over the site to bring the actual site model into conformity with the desired site model.
It will be apparent to those skilled in the art that the inventive method and system can be easily applied to monitor and cPntrol almost any compacting operation in which a machine travels over a work site to compact the site tu~uy ~ d~ in real - time . The l~ illustrated embodiments are provided to further an understanding of the broad principles of the invention, and to disclose in detail a preferred application . Many other modif ications or applications of the nvention can be made and still lie within the scope of the ~spp~n~ rl claim8.

.

Claims

1. Apparatus (120, 124, 126, 128) for directing the operations of a mobile site compacting machine (10) comprising:
(a) digital data storage and retrieval means (126) for storing a first site model (420) representing the desired degree of compaction of a site (12) and a second site model (430) representing the actual degree of compaction of the site (12);
(b) means (120) for generating digital signals representing in real time the instantaneous position in three-dimensional space of at least a portion of the compacting machine (10) as it traverses the site (12);
(c) means (124) for receiving said signals and for updating the second model (430) in accordance therewith;
(d) means (124) for determining the difference between the first and second models (420, 430) in real time; and (e) means (128) for directing the operation of the compacting machine (10) in accordance with the difference to bring the updated second model (430) into conformity with the first model (420) .

2. Apparatus (120, 124, 126, 128) as defined in claim 1, wherein the means (120) for generating three-dimensional position signals include a GPS receiver (120).

3. Apparatus (120, 124, 126, 128) as defined in claim 1, wherein the means (120) for generating three-dimensional position signals is carried on the machine (10) .

4. Apparatus (120, 124, 126, 128) as defined in claim 1, wherein the means (128) for directing the operation of the machine (10) include an operator display (22).

5. Apparatus (120, 124, 126, 128) as defined in claim 4, wherein the operator display (22) includes a plan view of the site models (420, 430) and the difference therebetween.

6. Apparatus (120, 124, 126, 128) as defined in claim 4, wherein the operator display (108) includes a real-time display of the position of the compacting machine (10) relative to the site models (420, 430).

7. Apparatus (120, 124, 126, 128) as defined in claim 4, wherein the operator display (22) is carried on the mobile machine (10).

8. Apparatus (120, 124, 126, 128) as defined in claim 4, wherein the operator display (22) is located off the mobile machine (10).

9. Apparatus (120, 124, 126, 128) as defined in claim 1, wherein the means (124) for receiving the position signals and updating the second model (430), and the means (50, 60) for determining the difference between the first and second models (420, 430) are located on the machine (10).

10. Apparatus (120, 124, 126, 128) as defined in claim 1, wherein the means (124) for receiving the position signals and updating the second model (430), and the means for determining the difference (124) between the first and second models (420, 430) are located off the machine (10) .

11. Apparatus (120, 124, 126, 128) as defined in claim 1, wherein the means (128) for directing the operation of the machine (10) include closed-loop automatic control means (470 ) connected to actuate one or more operating systems on the machine (10).

12. Apparatus (120, 124, 126, 128) as defined in claim 1, further including differencing means (124) for determining in real time the path of the machine (10) relative to the site (12) between position readings.

13. Apparatus (120, 124, 126, 123) as defined in claim 12, wherein the differencing means (124) includes means for determining an effective width (530') of a compacting portion (26, 28) of the machine (10) which is of a magnitude less than or equal to its actual width.

14. Apparatus (120, 124, 126, 128) as defined in claim 13, wherein the differencing means (124) includes means (540') for determining the area of the site traversed by the compacting portion of the machine (10) between position readings, and means (538) for updating the area of the second site model (430) traversed by the effective width of the compacting portion (26, 28).

15. Apparatus (120, 124, 126, 123) as defined in claim 1, wherein the first site model (420) comprises a predetermined desired degree of compaction of the site (12) relative to an uncompacted state, and the difference between the first and second site models (420, 430) comprises the difference between the actual degree of compaction of the site (12) and the desired degree of compaction of the site (12) .

16. Apparatus (120, 124, 126, 128) as defined in claim 15, wherein the difference between the first and second site models (420,430) is incremented between an uncompacted state of the site (12) and the desired degree of compaction, the means (124) for determining the difference between the first and second site models (420, 430) including means (554, 556, 578) for detecting the addition of uncompacted material to the site (12) and decrementing (560) the difference between the first and second site models (420,430) to the uncompacted state where the uncompacted material is detected.

17. Apparatus (120, 124, 126, 128) as defined in claim 15, wherein the degree of compaction is a function of one or more compacting passes by the machine (10) over the site (12), and the means (124) for determining the difference between the first and second site models (420, 430) include means for determining a number of compacting passes (562-590) by the machine (10) over the site (12) .

18. Apparatus (120, 124, 126, 128) as defined in claim 15, wherein the degree of compaction is a function of a change in the elevation of the site (12), and the means (124) for determining the difference between the first and second site models (420, 430) include means (550-560) for determining a change in the elevation of the site (12).

19. Apparatus (120, 124, 126, 128) as defined in claim 1, wherein the machine (10) comprises a landfill compactor.

20. Apparatus (120, 124, 126, 128) as defined in claim 1, wherein the machine (10) comprises an asphalt paving machine.

21. Apparatus (120, 124, 126, 128) as defined in claim 1, wherein the machine (10) comprises an earth compacting machine.

22. A method of directing the operation of a mobile site compacting machine (10) comprising the steps of:
(a) producing and storing in a digital data storage and retrieval means (126) both a first site model (420) representing the desired degree of compaction of the site (12) and a second site model (430) representing the actual degree of compaction of the site (12);
(b) generating signals (120) representing in real time the instantaneous position in three-dimensional space of at least a portion of the compacting machine (10) as it traverses the site (12);
(c) updating the second model (430) in accordance with said three-dimensional position signals;
(d) determining the difference (124) between the first and second site models; and (e) directing the operation (128) of the compacting machine (10) in accordance with the difference to bring the updated second site model (430) into conformity with the first site model (420).

23. A method as defined in claim 22, wherein the three-dimensional position signals are generated by a GPS receiver (120).

24. A method as defined in claim 22, wherein the three-dimensional position signals are generated by means (50) carried on the machine (10).

25 . A method as defined in claim 24, wherein the step of directing the operation of the machine (10) in accordance with the difference between the first and second site models (420, 430) includes providing an operator display (22) of the difference between the first and second site models (420, 430) .

26. A method as defined in claim 25, further including the step of displaying the difference between the first and second site models (420, 430) in a plan view (70) .

27. A method as defined in claim 25, further including the step of displaying a real time position of the machine (10) relative to the first and second site models (420,430).

28. A method as defined in claim 25, further including the step of providing the operator display (108) on the machine (10) .

29. A method as defined in claim 25, further including the step of providing the operator display (22) off the machine (10) .

30. A method as defined in claim 22, wherein the steps of updating the second model (430) and determining the difference between the first and second models (420, 430) are carried out by means (124) on the machine (10).

31. A method as defined in claim 22, wherein the steps of updating the second model (430) and determining the difference between the first and second models (420, 430) are carried out by means (124) off the machine (10) .

32. A method as defined in claim 22, wherein the step of directing the operation of the machine (10) in accordance with the difference between the first and second site models (420, 430) includes the step of delivering a signal to control operation of a machine system (470) to bring the second site model (430) into conformity with the first site model (420 ) .

33. A method as defined in claim 22, wherein the first site model (420) comprises a predetermined desired degree of compaction of the site relative to an uncompacted state, and the difference between the first and second site models (420, 430) is determined as the difference between the actual degree of compaction of the site (12) and the desired degree of compaction of the site ( 12 ) .

34. A method as defined in claim 33, wherein the difference between the first and second site models (420, 430) is incremented between an uncompacted state of the site and the desired degree of compaction and the step of determining the difference between the first and second site models (420, 430) includes the step (554, 556) of determining the addition of uncompacted material to the site and decrementing the difference between the first and second site models (420, 430) to the uncompacted state where the uncompacted material is detected.

35. A method as defined in claim 33, wherein the degree of compaction is determined as a function of a number of compacting passes (552-590) by the machine (10) over the site (12).

36. A method as defined in claim 33, wherein the degree of compaction is determined as a function of a change in the elevation (550-560) of the site (12) .

37. A method as defined in claim 22, wherein the step of updating the second model (430) in accordance with the position of the machine (10) includes the step of determining in real time the path of the machine (10) relative to the site (12) between the position readings.

38. A method as defined in claim 37, wherein the compacting machine (10) includes two spaced compacting wheels (26, 28) with site-contacting footprints, and the step of determining in real time the path of the machine (10) includes the step of determining in real time the path of the spaced footprints between position readings.

39. A method as defined in claim 38, wherein the step (40) of determining the real time path of the footprints between position readings includes the step of tracking (514-591) the line path of the centers (540') of the footprints between position readings.

40. A method as defined in claim 37, further including the step of determining an effective width (530) for a compacting portion of the machine (10) which is of a magnitude less than or equal to its actual width.

41. A method as defined in claim 40, further including the step (540' -548') of determining the area of the site traversed by the compacting portion of the machine (10) between position readings, and updating the area of the second site model (430) traversed by the effective width of the compacting portion (28) .

42. A method as defined in claim 22, including the step (60) of directing the operation of the machine (10) for landfill compacting.

43. A method as defined in claim 22, including the step of directing (128) the operation of the machine (10) for earth compacting.

44. A system for accurately monitoring and controlling (128) the compaction of a work site (12) and compaction machinery (10) operating on the work site (12), comprising:
a mobile compacting machine (10) for compacting the site (12), the machine (10) equipped with positioning means (50) to accurately determine in real time the instantaneous position of at least a portion of the machine (10) in three dimensions as it moves relative to the site (12);

a digital data storage facility (126) in communication with the positioning means (50) on the machine (10);
a first model (420) of a desired degree of site compaction, and a second model (430) of the actual degree of site compaction, the first and second site models stored in the digital data storage facility (126);
dynamic database means (124) communicating with the digital data storage facility (126) and the positioning means (120), the dynamic database means (124) monitoring the position of the machine (10) relative to the site (12) in real time and updating the second site model (430) in real time in response to the monitored position of the machine (10) as it traverses the site (12), the dynamic database means (120) further generating signals representing the difference in the degree of compaction between the first and second site models (420, 430) for directing the operation of the machine (10) to bring the second updated site model (430) into conformity with the first site model (420).

45. A system as defined in claim 44, further including operator display means (22) for communicating said signals with the dynamic database means (124), and displaying the difference between the first and second site models (420, 430) and the position of the machine (10) relative to the site (12).

46. A system as defined in claim 45, wherein the operator display (22) is located on the machine (10) .

47. A system as defined in claim 45, wherein the operator display (22) is located off the machine (10).

48. A system as defined in claim 44, wherein the dynamic database means (124) is located on the machine (10).

49. A system as defined in claim 44, wherein the dynamic database means (124) is located of f the machine ( 10 ).

50. A system as defined in claim 44, further including automatic control means (470) on the machine (10) in communication with the dynamic database means (400), the signals representing the difference between the first and second site models (420, 430) operating the automatic control means (470) to bring the second site model (430) into conformity with the first site model (420).

51. A system as defined in claim 44, wherein the positioning means (120) comprise a GPS
receiver.

52 . A system as defined in claim 44, wherein the positioning means (120) are mounted on the machine (10) at a known position relative to a portion of the machine (10) in contact with the site surface (12) .

53. A system as defined in claim 44, wherein the machine (10) is provided with positioning means (18, 18a) located at first and second spaced locations on the machine (10), said positioning means (18a) at the second location providing a directional reference relative to the positioning means at the first location (18).

54. A system as defined in claim 44, wherein the dynamic database includes differencing means (102) for determining in real time the path of the machine (10) relative to the site (12) between position readings.

55. A system as defined in claim 54, wherein the machine (10) includes two spaced compacting wheels (26, 28) with site-contacting footprints at a known, fixed position relative to the positioning means (18, 18a), the differencing means (124) determining in real time the path of the footprints relative to the site (12) between position readings.

56. A system as defined in claim 55, wherein the differencing means (102) includes a Bresenham's algorithm for determining the line path of the centers of the compacting wheel footprints (26, 28) of the compacting machine (10) between position readings .

57. A system as defined in claim 52, wherein the machine (10) includes a compacting portion (26, 28) of continuous width, and the dynamic database means (400) includes means (530') for determining an effective width for the compacting portion (26, 28) which is of a magnitude less than or equal to its actual width.

58. A system as defined in claim 57, wherein the differencing means (102) includes a fill-in-the-polygon algorithm (540') for determining the path traversed by the effective width of compacting portion (26, 28) of the machine (10) between position readings.

59. A system as defined in claim 58, wherein the dynamic database means (400) further includes means for updating the area (538) of the second site model (430) traversed by a compacting portion (26, 28) of the machine (10) .

60. A method for determining the path in real time of a mobile compacting machine (10) over a work site (12), comprising the steps of:
providing a model (104) of the site (12) subdivided into a continuous matrix of unit areas (71);
equipping the mobile machine (10) with means for determining the position (100) in three-dimensional space of at least a portion of the machine (10) as it traverses the site (12);
tracking the position (100) of the machine while it traverses the site (12) as a series of coordinate points on the site model (104);
determining the width of a compacting portion (26, 28) of the machine (10) relative to the unit areas (71) of the site model (104); and, where the rate at which the coordinate points are tracked is not synchronous with the rate of travel of the machine (10) over the unit areas of the site (12), determining a path for the machine in real time comprising the unit areas (71) traversed by the compacting portion of the machine (10) between coordinate points.

61. A method as defined in claim 60, wherein the compacting machine (10) includes two spaced compacting wheels (26,28) with site-contacting footprints, and the step of determining in real time the path of the machine (10) includes the step of determining in real time the path of the spaced footprints between position readings.

62. A method as defined in claim 61, wherein the step of determining the real time path of the footprints between position readings includes the step of tracking (514, 591) the line path of the centers (540) of the footprints between position readings.

63. A method as defined in claim 60, wherein the width (530) of the compacting portion of the machine (10) is determined as an effective width which is less than or equal to its actual width, and the path of the machine (10) over the site (12) as represented on the site model is determined by the path of the effective width of the compacting portion.

64. A method as defined in claim 63, wherein the effective width is determined by locating each effective end of the operative portion of the machine (10) from each actual end a distance corresponding to a fraction of the width of one unit area on the site model (12).

65. A method as defined in claim 63, wherein the compacting portion (26,28) of the machine (10) comprises a plurality of geography-altering portions.

66. A method as defined in claim 60, further including the step of updating the degree of compaction of each unit area of the site model (106) over which the compacting portion (26, 28) is determined to have passed.

67. A method for precisely determining the position of a compacting machine (10) in three-dimensional space relative to a land site (12) using three-dimensional position signals and a digitized model of the site, the invention comprising the steps of:
(a) equipping the compacting machine (10) to receive the position signals;
(b) producing and storing a site model (106) representing the degree of compaction of the site in a digital data storage facility (50);
(c) operating the compacting machine (10) on the site (12) while simultaneously updating the site model in the storage facility (126) in real time according to the three-dimensional position of at least a portion of the machine (10) relative to the site (12).

68. A method as defined in claim 67, wherein the site model (106) is an actual site model (430) representing the actual degree of compaction of the site (12).

69. A method as defined in claim 68, further including the step of producing and storing a desired site model (420) representing a desired degree of compaction of the site (12) in the digital data storage facility (126), and determining in real time the difference between the actual site model (430) and the desired site model (420) as the actual site model (430) is updated.

70. A system as defined in claim 69, wherein the machine (10) includes two spaced compacting wheels (26, 28) with site-contacting footprints at a known, fixed position relative to the positioning means (18), the differencing means (102) determining in real time the path of the footprints relative to the site (12) between position readings.

71. A system as defined in claim 70, wherein the differencing means (102) includes a Bresenham's algorithm for determining the line path of the centers of the compacting wheel footprints of the compacting machine (10) between position readings.

72. A method as defined in claim 67, wherein the degree of compaction of the site (12) is a function of the elevation of the site surface.

73. A method as defined in claim 67, wherein the degree of compaction of the site (12) is a function of a number of passes by the compacting machine (10) over the site (12).

74. A method as defined in claim 69, wherein the desired site model (420) comprises a predetermined desired range of compaction of the site relative to an uncompacted state, and the difference between the first and second site models (420, 430) comprises the difference between the actual degree of compaction of the site (12) and the desired degree of compaction of the site (12).

75. A method as defined in claim 74, wherein the difference between the first and second site models (420, 430) is incremented between an uncompacted state of the site (12) and the desired degree of compaction, and the step of determining the difference between the first and second site models includes the step of determining the addition of uncompacted material (554) to the site and decrementing the difference between the first and second site models (420, 430) to the uncompacted state (552) where the uncompacted material is detected.

76. A method as defined in claim 67, wherein the invention further includes the step of displaying and updating the site model (70) to an operator of the machine (10) in real time.

77. An apparatus for precisely determining the position of a compacting machine (10) in three-dimensional space relative to a land site (12) using three-dimensional position signals and a digitized model of the site (12), comprising:
(a) a mobile machine (10) equipped with means (124) for receiving the position signals and for determining the instantaneous position in three-dimensional space of at least a compacting portion (26, 28) of the machine as it traverses the site (12);
(b) a model (430) of the degree of compaction of the site stored in a digital data storage facility (120);
(c) dynamic database means (124) communicating with the means for determining the machine position (120) and the digital data storage facility (126), the dynamic database means (124) including means for updating the site model in the storage facility (126) in real time according to the three-dimensional position of at least the compacting portion (26, 28) of the machine (10) relative to the site ( 12 ).

78. Apparatus (120, 124, 126, 128) as defined in claim 77, wherein the site model is an actual site model (430) representing an actual degree of compaction of the site.

79. Apparatus (120, 124, 126, 128) as defined in claim 77, wherein a desired site model (420) of a desired degree of compaction of the site is stored in the digital storage facility (126), and the dynamic database means (124) include differencing means (102) for determining in real time the difference between the actual site model (430) and the desired site model (420) as the actual site model ( 4 3 0 ) is updated.

80. Apparatus (120, 124, 126, 128) as defined in claim 79, wherein the first site model (420) comprises a predetermined desired degree of compaction of the site relative to an uncompacted state, and the difference between the first and second site models (420, 430) comprises the difference between the actual degree of compaction of the site (12) and the desired degree of compaction of the site (12) .

81. Apparatus (120, 124, 126, 128) as defined in claim 80, wherein the difference between the first and second site models (420, 430) is incremented between an uncompacted state and the desired degree of compaction, and the step of determining the difference between the first and second site models includes the step of determining the addition of uncompacted material to the site (12) and decrementing the difference between the first and second site models (420, 430) to the uncompacted state where the uncompacted material is detected.

82. Apparatus (120, 124, 126, 128) as defined in claim 77, wherein the apparatus includes means (22) for displaying the updated site model (430) to an operator of the machine (10) in real time.

83. Apparatus (120, 124, 126, 128) as defined in claim 82, wherein the operator display means (22) are located on the machine (10).

84. Apparatus (120, 124, 126, 128) as defined in claim 82, wherein the operator display means (22) are located off the machine (10).

85. Apparatus (120, 124, 126, 128) as defined in claim 77, wherein the dynamic database means (122) are located on the machine.

86. Apparatus (120, 124, 126, 128) as defined in claim 83, wherein the dynamic database means (122) are located off the machine (10) and the apparatus further includes means for transmitting signals representing the updated site model from the dynamic database means (122) off the machine to the operator display means (22) on the machine (10), and means for transmitting the machine position to the dynamic database means (124).