ROUTINE FOR JUDGING EVACUATION POSSIBILITY USING OWN TRAVELING PATH C
VEHICLE SURROUNDINGS MONITORING APPARATUS AND TRAVELING CONTROL SYSTEM INCORPORATING THE APPARATUS
BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention
[0002] The present invention relates to a vehicle surroundings monitoring apparatus for recognizing traveling circumstances in front of an own vehicle by stereoscopic cameras, monocular cameras, millimeter wave radars, and the like and for accurately estimating traveling paths of an own vehicle and a traveling control system incorporating such a vehicle surroundings monitoring apparatus.
[0003] 2. Discussion of Related Arts
[0004] In recent years, such a traveling control system as detecting traveling circumstances in front of an own vehicle by a camera and the like mounted on a vehicle, estimating traveling paths of the own vehicle from the traveling circumstances data, detecting a preceding vehicle traveling ahead of the own vehicle and making a follow-up control of the preceding vehicle or an intervehicle distance control between the own vehicle and the preceding vehicle, has been put into practical use. For example, Japanese Patent Application Laid-open No. Toku-Kai-Hei 9-91598 discloses a traveling control system in which a traveling path of an own vehicle is estimated from traveling conditions such as yaw rate and other data and a nearest obstacle on the traveling path is detected as a preceding vehicle to be monitored. Further, in the traveling control system, when the preceding vehicle goes out of the traveling path of the own vehicle, the monitoring of the preceding vehicle is released.
[0005] However, the prior technology in which a traveling path of an own vehicle (hereinafter referred to just as own traveling path) is estimated and a preceding vehicle is caught based on the own traveling path, has a defect that if the estimation of the own traveling path is inaccurate, the capture of the preceding vehicle itself loses reliability and as a result a desired traveling control can not be realized.
SUMMARY OF THE INVENTION
[0006] It is an object of the present invention to provide a vehicle surroundings monitoring apparatus capable of stably estimating an own traveling path with high precision and to provide a traveling control system incorporating such a vehicle surroundings monitoring apparatus.
[0007] According to the present invention, a vehicle surroundings monitoring apparatus inputs images taken by a stereoscopic camera, vehicle speeds, sterring wheel rotation angles, yaw rates and ON-OFF signals of a turn signal switch. An own traveling path C is calculated from an own traveling path A obtained from lane markers and side walls and an own traveling path B obtained from yaw rates of the own vehicle. Further, a new own traveling path E is calculated from the own traveling path C and a trace of a preceding vehicle in case where there is no possibility of evacuation of the preceding vehicle and the turn signal switch is turned off and the absolute value of the steering wheel rotation angle is smaller than a specified value and a present own traveling path is calculated from the own traveling path E and the previous own traveling path. In
other cases, the present own traveling path is calculated from the own traveling path C and the previous own traveling path.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 is a schematic diagram showing a traveling control system incorporating a vehicle surroundings monitoring apparatus according to the present invention;
[0009] FIG. 2 is a flowchart showing a routine for monitoring surroundings of a vehicle;
[0010] FIG. 3 is a flowchart showing a routine for estimating a traveling path of an own vehicle;
[0011] FIG. 4 is a flowchart showing a routine for judging the possibility of evacuation of a preceding vehicle using a traveling path C of an own vehicle;
[0012] FIG. 5a is an explanatory diagram showing a process of producing a new traveling path C of an own vehicle from the traveling path A and the traveling path B;
[0013] FIG. 5b is an explanatory diagram showing a process of producing the new traveling path C when the traveling path A is erroneously recognized;
[0014] FIG. 5c is an explanatory diagram showing a process of calculating a new traveling path E from the traveling path C and the traveling path D (traveling path of a preceding vehicle); and
[0015] FIG. 6 is an explanatory diagram showing a process for establishing a judging counter.
DESCRIPTION OF THE PREFERRED
EMBODIMENT
[0016] Referring now to FIG. 1, reference numeral 1 denotes a vehicle (own vehicle) on which an intervehicle distance automatically adjusting system (Adaptive Cruise Control: ACC) 2 is mounted. The ACC system 2 is constituted by a traveling control unit 3, a stereoscopic camera 4 and a vehicle surroundings monitoring apparatus 5. When the ACC system is set to a constant speed control mode, the vehicle travels at a speed established by a vehicle driver and when the system is set to a follow-up traveling control mode, the vehicle travels at a speed targeted to the speed of a preceding vehicle with a constant intervehicle distance to the preceding vehicle maintained.
[0017] The stereoscopic camera 4 constituting vehicle forward information detecting means is composed of a pair (left and right) of CCD cameras using a solid-state image component such as Charge Coupled Device and the left and right cameras are transversely mounted on a front ceiling of a passenger compartment at a specified interval of distance, respectively. The respective cameras take picture images of an outside object from different view points and input the picture images to the vehicle surroundings monitoring apparatus 5.
[0018] Further, the vehicle 1 has a vehicle speed sensor 6 for detecting a vehicle speed and the detected vehicle speed is inputted to the traveling control unit 3 and the vehicle surroundings monitoring apparatus 5, respectively. Further, the vehicle 1 has a steering angle sensor 7 for detecting a steering angle and a yaw rate sensor 8 for detecting a yaw rate and the detected steering angle and yaw rate signals are
inputted to the vehicle surroundings monitoring apparatus 5. Further, a signal from a turn signal switch 9 is inputted to the vehicle surroundings monitoring apparatus 5. These sensors 6, 7, 8 and the switch 9 act as own vehicle traveling conditions detecting means.
[0019] The vehicle surroundings monitoring apparatus 5 inputs respective signals indicative of picture images from the stereoscopic camera 4, vehicle speeds, steering angle, yaw rate and turn signal and detects frontal information about solid objects, side walls and lane markers in front of the vehicle 1 based on the picture images inputted from the stereoscopic camera 4. Then, the apparatus estimates several traveling paths of the own vehicle 1 from the frontal information and traveling conditions of the own vehicle 1 according to the flowchart which will be described hereinafter and estimates a final traveling path of the own vehicle 1 from those traveling paths. Further, the apparatus establishes a traveling region A corresponding to a detected solid object based on the final traveling path. Further, the apparatus establishes a traveling region B corresponding to the solid object based on at least either of the traveling region A and the traveling road information and judges whether the solid object is a preceding vehicle, a tentative preceding vehicle or others according to the state of existence of the solid object in the traveling regions A and B. As a result of the judgment, a preceding vehicle in front of the own vehicle 1 is extracted and the result is outputted to the traveling control unit 3. The vehicle surroundings monitoring apparatus 5 includes frontal information detecting means, first own traveling path calculating means, second own traveling path calculating means, third own traveling path calculating means and final own traveling path calculating means.
[0020] Describing the process of estimating the own traveling path in brief, a new own traveling path C is calculated from the own traveling path A (first own traveling path) obtained based on lane markers and side walls and the own traveling path B (second own traveling path) obtained based on yaw rates of the own vehicle. Then, the possibility of evacuation of the preceding vehicle is judged from the relationship between the own traveling path C, the preceding vehicle and the solid object in the vicinity of the preceding vehicle. In case where there is no possibility of evacuation of the preceding vehicle, the turn signal switch is turned off, and the absolute value of the steering wheel rotation angle is smaller than a specified value, a new own traveling path E is calculated from the own traveling path C and the locus of the preceding vehicle and a present own traveling path is calculated from the own traveling path E and the previous own traveling path. On the other hand, in case where the conditions described above are not satisfied, a present own traveling path is calculated from the own traveling path C and the previous own traveling path. The vehicle surroundings monitoring apparatus 5 comprises forward information detecting means, preceding vehicle recognizing means, own traveling path estimating means, first evacuation possibility judging means and second evacuation possibility judging means.
[0021] Describing the processing of images from the stereoscopic camera 4 in the vehicle surroundings monitoring apparatus 5, with respect to a pair of stereoscopic images taken by the stereoscopic CCD camera 4, distance information over the entire image is obtained from the deviation amount between corresponding positions according to the
principle of trianguration and a distance image representing three-dimensional distance distribution is formed based on the distance information. Then, lane marker data, side wall data such as guardrails, curbs and side walls arranged along the road and solid object data such as vehicles and the like, are extracted by means of the known grouping process and the like by comparing the distance image with the threedimensional road profile data, side wall data, solid object data and the like stored beforehand. Thus extracted lane marker data, side wall data and solid object data are denoted by different numbers respectively. Further, the solid object data are classified into three kinds of objects, a backward moving object moving toward the own vehicle 1, a still object in standstill and a forward moving object moving in the same direction as the own vehicle 1 based on the relationship between the relative displacement of the distance from the own vehicle and the vehicle speed of the own vehicle 1 and the respective solid object data are outputted.
[0022] The traveling control unit 3 is equipped with a function of a constant speed traveling control for maintaining the vehicle speed at a value inputted by the vehicle driver and a function of a follow-up traveling control for following up the preceding vehicle in a condition to keep the intervehicle distance between the own vehicle 1 and the preceding vehicle constant. The traveling control unit 3 is connected with a constant speed traveling switch 10 constituted by a plurality of switches operated by a constant speed traveling selector lever provided on the side surface of a steering column, the vehicle surroundings monitoring apparatus 5, the vehicle speed sensor 6 and the like.
[0023] The constant speed traveling switch 10 is constituted by a speed setting switch for setting a target vehicle speed at the constant speed traveling mode, a coast switch for changing the target vehicle speed in a descending direction and a resume switch for changing the target vehicle speed in an ascending direction. Further, a main switch (not shown) for turning the traveling control on or off is disposed in the vicinity of the constant speed traveling selector lever.
[0024] When the driver turns a main switch (not shown) on and sets a desired vehicle speed by operating the constant speed traveling selector lever, a signal indicative of the desired vehicle speed inputs from the constant speed traveling switch 10 to the traveling control unit 3 and a throttle valve 12 driven by a throttle actuator 11 makes a feed-back control so as to converge the vehicle speed detected by the vehicle speed sensor 6 to the established vehicle speed. As a result, the own vehicle 1 can travel at a constant speed automatically.
[0025] Further, when the traveling control unit 3 makes a constant traveling control, supposing a case where the vehicle surroundings monitoring apparatus 5 recognizes a preceding vehicle, which is traveling at a lower speed than the established vehicle speed, the traveling control unit 3 automatically changes over to a follow-up traveling control mode in which the own vehicle travels in a condition retaining at a constant intervehicle distance.
[0026] When the constant speed traveling control mode is transferred to the follow-up traveling control mode, a target value of an appropriate intervehicle distance between the own vehicle 1 and the preceding vehicle is established based on the intervehicle distance obtained from the vehicle surroundings monitoring apparatus 5, the vehicle speed of the
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