WO2005048887A1 - Instrumented prosthetic foot - Google Patents

Instrumented prosthetic foot Download PDF

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Publication number
WO2005048887A1
WO2005048887A1 PCT/CA2003/001802 CA0301802W WO2005048887A1 WO 2005048887 A1 WO2005048887 A1 WO 2005048887A1 CA 0301802 W CA0301802 W CA 0301802W WO 2005048887 A1 WO2005048887 A1 WO 2005048887A1
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WO
WIPO (PCT)
Prior art keywords
prosthetic foot
instrumented prosthetic
sensors
foot according
instrumented
Prior art date
Application number
PCT/CA2003/001802
Other languages
French (fr)
Inventor
Stéphane BEDARD
Pierre-Olivier Roy
Original Assignee
Victhom Human Bionics Inc.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Victhom Human Bionics Inc. filed Critical Victhom Human Bionics Inc.
Priority to EP03776700A priority Critical patent/EP1684676A1/en
Priority to CA2543061A priority patent/CA2543061C/en
Priority to KR1020067009718A priority patent/KR101007946B1/en
Priority to CN2003801107082A priority patent/CN1878517B/en
Priority to JP2005510677A priority patent/JP4320017B2/en
Priority to PCT/CA2003/001802 priority patent/WO2005048887A1/en
Priority to AU2003286026A priority patent/AU2003286026B2/en
Publication of WO2005048887A1 publication Critical patent/WO2005048887A1/en
Priority to AU2010200238A priority patent/AU2010200238B2/en

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Classifications

    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61FFILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F2/00Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
    • A61F2/50Prostheses not implantable in the body
    • A61F2/60Artificial legs or feet or parts thereof
    • A61F2/66Feet; Ankle joints
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61FFILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F2/00Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
    • A61F2/50Prostheses not implantable in the body
    • A61F2/68Operating or control means
    • A61F2/70Operating or control means electrical
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61FFILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F2/00Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
    • A61F2/50Prostheses not implantable in the body
    • A61F2/60Artificial legs or feet or parts thereof
    • A61F2/66Feet; Ankle joints
    • A61F2/6607Ankle joints
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61FFILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F2/00Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
    • A61F2/50Prostheses not implantable in the body
    • A61F2/68Operating or control means
    • A61F2/70Operating or control means electrical
    • A61F2/72Bioelectric control, e.g. myoelectric
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61FFILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F2/00Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
    • A61F2/50Prostheses not implantable in the body
    • A61F2/76Means for assembling, fitting or testing prostheses, e.g. for measuring or balancing, e.g. alignment means
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61FFILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F2/00Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
    • A61F2/50Prostheses not implantable in the body
    • A61F2/60Artificial legs or feet or parts thereof
    • A61F2/64Knee joints
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61FFILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F2/00Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
    • A61F2/50Prostheses not implantable in the body
    • A61F2002/5003Prostheses not implantable in the body having damping means, e.g. shock absorbers
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61FFILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F2/00Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
    • A61F2/50Prostheses not implantable in the body
    • A61F2002/5007Prostheses not implantable in the body having elastic means different from springs, e.g. including an elastomeric insert
    • A61F2002/5009Prostheses not implantable in the body having elastic means different from springs, e.g. including an elastomeric insert having two or more elastomeric blocks
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61FFILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F2/00Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
    • A61F2/50Prostheses not implantable in the body
    • A61F2/60Artificial legs or feet or parts thereof
    • A61F2/66Feet; Ankle joints
    • A61F2002/6614Feet
    • A61F2002/6642Heels
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61FFILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F2/00Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
    • A61F2/50Prostheses not implantable in the body
    • A61F2/60Artificial legs or feet or parts thereof
    • A61F2/66Feet; Ankle joints
    • A61F2002/6614Feet
    • A61F2002/6657Feet having a plate-like or strip-like spring element, e.g. an energy-storing cantilever spring keel
    • A61F2002/6671C-shaped
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61FFILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F2/00Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
    • A61F2/50Prostheses not implantable in the body
    • A61F2/60Artificial legs or feet or parts thereof
    • A61F2/66Feet; Ankle joints
    • A61F2002/6614Feet
    • A61F2002/6657Feet having a plate-like or strip-like spring element, e.g. an energy-storing cantilever spring keel
    • A61F2002/6685S-shaped
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61FFILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F2/00Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
    • A61F2/50Prostheses not implantable in the body
    • A61F2/68Operating or control means
    • A61F2/70Operating or control means electrical
    • A61F2002/705Electromagnetic data transfer
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61FFILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F2/00Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
    • A61F2/50Prostheses not implantable in the body
    • A61F2/76Means for assembling, fitting or testing prostheses, e.g. for measuring or balancing, e.g. alignment means
    • A61F2002/7615Measuring means
    • A61F2002/7625Measuring means for measuring angular position
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61FFILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F2/00Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
    • A61F2/50Prostheses not implantable in the body
    • A61F2/76Means for assembling, fitting or testing prostheses, e.g. for measuring or balancing, e.g. alignment means
    • A61F2002/7615Measuring means
    • A61F2002/7635Measuring means for measuring force, pressure or mechanical tension
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61FFILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F2/00Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
    • A61F2/50Prostheses not implantable in the body
    • A61F2/76Means for assembling, fitting or testing prostheses, e.g. for measuring or balancing, e.g. alignment means
    • A61F2002/7615Measuring means
    • A61F2002/764Measuring means for measuring acceleration

Definitions

  • an instrumented prosthetic foot for use with an actuated leg prosthesis controlled by a controller, the instrumented prosthetic foot comprising a connector to connect the instrumented prosthetic foot to the leg prosthesis, an ankle structure connected to the connector, a ground engaging member connected to the ankle, at least one sensor for detecting changes in weight distribution along the foot, and an interface for transmitting signals from the sensor to the controller.
  • FIG. 1 shows the lower body of an individual provided with a prosthesis and an instrumented prosthetic foot on one side and having a healthy leg on the other side.
  • FIG. 2 is a block diagram showing a control system for a prosthesis having an actuating mechanism.
  • FIG. 3 is a perspective view, from the front and slightly above, of a instrumented prosthetic foot.
  • FIG. 4 is an exploded perspective view of the instrumented prosthetic foot of FIG. 3.
  • FIG. 5 is a perspective view, from the front and slightly above, of an alternative embodiment of the instrumented prosthetic foot of FIG. 3.
  • FIG. 6 is an exploded perspective view of the instrumented prosthetic foot of FIG. 5.
  • FIG. 7 is a perspective view, from the front and slightly above, of another alternative embodiment of the instrumented prosthetic foot of FIG. 3
  • FIG. 8 is an exploded perspective view of the instrumented prosthetic foot of FIG. 7.
  • FIG. 9 is schematic view of forces exerted on a foot.
  • FIG. 10 is a perspective view, from the front and slightly above, of a further still alternative embodiment of the instrumented prosthetic foot of FIG. 3
  • FIG. 11 is an exploded perspective view of the instrumented prosthetic foot of FIG. 10.
  • FIG. 12 is a perspective view, from the front and slightly above, of a yet further still alternative embodiment of the instrumented prosthetic foot of FIG. 3
  • FIG. 13 is an exploded perspective view of the instrumented prosthetic foot of FIG. 12.
  • FIG. 14 is a perspective view, from the front and slightly above, of a further alternative embodiment of the instrumented prosthetic foot of FIG. 3
  • FIG. 15 is an exploded perspective view of the instrumented prosthetic foot of FIG. 14.
  • the appended figures show a instrumented prosthetic foot (20) having sensors (22A, 22B) for use, in cooperation with possible additional sensors (24A, 24B, 26), with a control system (100) for controlling a prosthesis (14) having an actuating mechanism (16). It should be understood that the present invention is not limited to the illustrated implementation since various changes and modifications may be effected herein without departing from the scope of the appended claims.
  • an individual (10) has a pair of legs (26) and (28), one of which, (26), is amputated above the knee.
  • a prosthesis (14) is attached to the leg (26) and includes an actuating mechanism (16), which may be either passive or active.
  • An instrumented prosthetic foot (20) is attached to the prosthesis (14) and includes sensors (22A, 22B). Additional sensors (24A, 24B) are located on the healthy foot and additional sensors (26) located on the individual (10) and/or the prosthesis (14).
  • a passive actuating mechanism may be generally defined as an electro-mechanical component that only absorbs mechanical energy in order to modify dynamics of mechanical joints of the prosthesis, while an active actuating mechanism may be generally defined as an electro-mechanical component that absorbs and supplies mechanical energy in order to set dynamics of mechanical joints of the prosthesis.
  • An example of a passive actuating mechanism is described in U.S. patent application No. 09/767,367, filed January 22, 2001 , entitled “ELECTRONICALLY CONTROLLED PROSTHETIC KNEE”.
  • Examples of active actuating mechanisms are described in U.S. patent application No. 10/463,495 filed June 17, 2003, entitled “ACTUATED PROSTHESIS FOR ABOVE-KNEE AMPUTEES", by Stephane Bedard et al., the entire disclosure of which is hereby incorporated by reference herein.
  • the prosthesis (14) is controlled, as shown schematically in FIG. 2, by a basic control system (100) comprising sensors (22A, 22B, 24A, 24B, 26), connected through an interface (30) to a controller (40).
  • the controller (40) provides signals to an actuating mechanism (16) in the prosthesis (14) , such as shown in FIG. 1.
  • the purpose of the control system (100) is to provide the required signals for controlling the actuating mechanism (16). To do so, the control system (100) is interfaced with the amputee (10) using sensors (22A, 22B, 24A, 24B, 26) to ensure proper coordination between the amputee (10) and the movements of the prosthesis (14).
  • the sensors (22A, 22B, 24A, 24B, 26) capture information, in real time, about the dynamics of the amputee's movement and provide that information to the controller (40) via the interface (30).
  • the controller (40) uses the information to determine the resistance to be applied to a joint, in the case of a passive actuating mechanism, or the joint trajectories and the required angular force or torque that must be applied by a joint, in the case of an active actuating mechanism, in order to provide coordinated movements.
  • the sensors (22A, 22B, 24A, 24B, 26) may include myoelectric sensors, neuro- sensors, kinematic sensors, kinetic sensors, strain gauges or plantar pressure sensors.
  • Myoelectric sensors are electrodes used to measure the internal or the external myoelectrical activity of skeletal muscles.
  • Neuro-sensors are electrodes used to measure the summation of one or more action potentials of peripheral nerves.
  • Kinematic sensors are used to measure the position of articulated joints, the mobility speed or acceleration of lower extremities.
  • Kinetic sensors are used to measure angular forces at articulated joints or reaction forces of lower extremities.
  • Strain gages are used to measure the strain forces at a specific underfoot area.
  • Plantar pressure sensors are used to measure the vertical plantar pressure of a specific underfoot area.
  • sensors which provide various information about dynamics of human locomotion may be used.
  • sensors 22A, 22B, 24A, 24B, 26
  • sensors 22A, 22B, 24A, 24B, 26
  • the sensors (22A, 22B, ) may comprise localized plantar pressure sensors located at spaced locations on the prosthetic foot (20) to measure the vertical plantar pressure of a specific underfoot area.
  • the plantar pressure sensors (24A, 24B) located on the side of the healthy foot may be provided at spaced locations in a custom-made insole, preferably in the form of a standard orthopaedic insole, that is modified to embed the two sensors (24A, 24B) for the measurement of two localized plantar pressures.
  • the sensors (22A, 22B, 24A, 24B) are operable to measure the weight transfer along the foot as the individual moves which may be combined with other sensors (26) such as kinematic sensors to measure the angular speed of body segments of the lower extremities and kinematic sensors to measure the angle of the prosthesis (14) knee joint.
  • Each sensor (22A, 22B, 24A, 24B) may comprise a thin Force-Sensing Resistor (FSR) polymer cell directly connected to the interface (30) of the control system
  • FSR Force-Sensing Resistor
  • the FSR cell has a decreasing electrical resistance in response to an increasing force applied perpendicularly to the surface thereof.
  • Each cell outputs a time variable electrical signal for which the intensity is proportional to the total vertical plantar pressure over its surface area.
  • the size and position of the plantar pressure sensors (22A, 22B, 24A, 24B) may be defined in accordance with the stability and the richness (intensity) of the localized plantar pressure signals provided by certain underfoot areas during locomotion. For example, it was found by experimentation that the heel and the toe regions are two regions of the foot sole where the Plantar Pressure Maximum Variation (PPMV) may be considered as providing a signal that is both stable and rich in information.
  • PPMV Plantar Pressure Maximum Variation
  • the controller (40) may use the data signals from the four localized plantar pressure sensors (22A, 22B, 24A, 24B), as well as the information gathered from the data signals of the other sensors (26) such as kinematic sensors, in order to decompose the locomotion of the individual (10) into a finite number of states, and generate the appropriate control signals for controlling the actuating mechanism (16) according to the locomotion.
  • the controller (40) is not limited to the use of the preceding data signals.
  • An example of a controller (40) and control system (100) using sensors comprising plantar pressure sensors as well as kinematic sensors is described in U.S.
  • the instrumented prosthetic foot (20) includes a foot plate (53), forming an elongated body, with a connector (51) at one end, a toe plate (55A) and a heel plate (55B) that is cantilevered from the foot plate (53).
  • a foot plate 53
  • a connector 511
  • a toe plate 55A
  • a heel plate 55B
  • Pressure sensors 22A, 22B
  • Pressure sensors are located at longitudinally spaced locations on the underside of the foot plate (53) and heel plate (55) respectively.
  • the sensors (22A, 22B) are covered by rigid plates (52A, 52B) and resilient pads (54A, 54B).
  • the pressure sensors (22A, 22B) are located so as to be responsive to loads imposed on the instrumented prosthetic foot (20) at the regions corresponding to the toe area and the heel area respectively.
  • the pads (54A, 54B) wrap up the rigid plates (52A, 52B) and the sensors (22A, 22B), forming a ground engaging member, in order to optimize the contact between the instrumented prosthetic foot (20) and the ground.
  • the pads (54A, 54B) may be made of 40A durometer polyurethane. Of course, other type of material may be used as well.
  • the force applied to the heel plate (55B) is measured by the sensor (22B) and a corresponding signal forwarded to the controller (40).
  • the force applied to the toe plate (55A) is also measured by the sensor (22A) and the relative loading between the two locations is measured.
  • the force applied to the toe area increases and that at the heel decreases to provide a pair of signals from which the disposition of the leg may be determined and the appropriate control provided to the actuator (16).
  • the instrumented prosthetic foot (20) includes connector (61), foot plate (63), toe plate (64A) and heel plate (64B), such as provided by, for example, a Vari-Flex® prosthetic foot from Ossur.
  • Pressure sensors (22A, 22B) are located between the foot plate (63) and rigid plates (62A, 62B). The pressure sensors (22A, 22B) are located so as to be responsive to load imposed on the instrumented prosthetic foot (20) at the regions corresponding to the toe area and the heel area respectively.
  • pressure sensor (22A) is sandwiched between a pair of rigid plates (62A), which in turn are positioned between the heel plate (64B) and the foot plate (63).
  • Pressure sensor (22B) is sandwiched between a pair of rigid plates (62B), which in turn are positioned between the foot plate (63) and the connector (61 ).
  • FIGS 7 and 8 Another alternative embodiment of the instrumented prosthetic foot (20) is shown in FIGS 7 and 8.
  • the instrumented prosthetic foot (20) includes connector (71), top foot plate (75), foam cushion core (73) and bottom foot plate (74), such as provided by, for example, a LP Talux® prosthetic foot from Ossur.
  • Pressure sensors (22A, 22B) are sandwiched between pairs of rigid plates (72A, 72B). The pressure sensors (22A, 22B) are located so as to be responsive to load imposed on the instrumented prosthetic foot (20) at the regions corresponding to the toe area and the heel area respectively.
  • pressure sensor (22A) is sandwiched between a pair of rigid plates (72A), which in turn are positioned within gap (76A), which is located between a bottom foot plate (74) and a foam cushion core (73).
  • Pressure sensor (22B) is sandwiched between a pair of rigid plates (72B), which in turn are positioned within gap (76B), which is located within the foam cushion core (73).
  • sensors (22A, 22B) may not be restricted to being positioned directly at the toe and heel areas, the equivalent information may be obtained by measuring the equivalent torque at the ankle and the axial force at the connector of the instrumented prosthetic foot (20).
  • F_toe and F_heel may be defined in terms of the torque measured at the ankle, M_ankle_meas, and the force measured at the connector, F_conn_meas, using the following equations:
  • the instrumented prosthetic foot (20) includes connector (81 ), foot plate (83), toe plate (84A) and heel plate (84B), such as provided by, for example, a Vari-Flex® prosthetic foot from Ossur, and load cells (22A, 22B).
  • Load cells (22A, 22B) are located below connector (91), load cell (22A) being slightly biased towards the toe area of the foot and load cell (22B) being slightly biased towards the heel area.
  • F_22B is the force measured at sensor 22B
  • F_22A is the force measured at sensor 22A; l_22B is the distance between the center of the connector (81 ) and the center of sensor 22B; l_22A is the distance between the center of the connector (81 ) and the center of sensor 22A.
  • the force (or pressure) at the toe and heel areas, F_toe and F_heel respectively was obtained either by positioning pressure sensors (22A, 22B) directly at those areas or by positioning pressure sensors or load cells (22A, 22B) in other areas and obtaining the equivalent information by computing the equivalent torque at the ankle and the axial force at the connector.
  • Other types of sensors may also be used to obtain the equivalent torque at the ankle and the axial force at the connector.
  • FIGS 12 and 13 The instrumented prosthetic foot (20) includes connector (91 ), mounted on pivoting ankle (93).
  • Bumpers (92A, 92B) are positioned between the pivoting ankle (93) and rocker plate (95) located on a foot plate (94).
  • the pivoting ankle (93) is connected to the rocker plate (95) by a pivot pin (96).
  • Such an arrangement is provided by, for example, an Elation® prosthetic foot from Ossur.
  • a load cell (22A) and an optical encoder (22B). are incorporated into the foot (20) to provide measurement of the distribution of forces along the foot (20).
  • Load cell (22A) is positioned between connector (91 ) and pivoting ankle (93).
  • Optical encoder (22B) comprises reader (221) and disk (223).
  • Equation 3 and Equation 4 may be used, for example by controller (40), to compute the equivalent pressures at the toe and heel areas by defining the equivalent torque at the ankle and the axial force at connector (91) as follows:
  • F_22A is the force measured at sensor 22A
  • R_ankle_meas is the rotation measurement of pivoting an kle (93) about pivot pin (96) as measured by optical encoder (22B);
  • R_const is a constant associated with the resistance of bumpers (92A, 92B) to compression, which constant varies depending in the material used.
  • FIGS 14 and 15 A yet further alternative embodiment of the instrumented prosthetic foot (20) is shown in FIGS 14 and 15.
  • the instrumented prosthetic foot (20) includes connector (101 ), mounted on pivoting ankle (103). Bumpers (102A, 1O2B) are positioned between the pivoting ankle (103) and rocker plate (105) located on a foot plate (104). The pivoting ankle (103) is connected to the rocker plate (105) by a pivot pin (106).
  • Such an arrangement is provided by, for example, an Elation® prosthetic foot from Ossur.
  • Pressure sensors (22A, 22B) and load cell (22C) are incorporated into the foot (20) to provide measurement of the distribution of forces along the foot (20).
  • Pressure sensor (22A) is positioned between rocker plate (85) and bumper (82A) while pressure sensor (22B) is positioned between rocker plate (85) and bumper (82B).
  • a load cell (22C) is positioned between connector (91) and pivoting ankle (93).
  • Load cell (22C) is required to compute the axial force at connector (101 ) since when there is no torque at the ankle, i.e. the wearer of the prosthesis is standing still, the axial force is being exerted in its entirety onto pivot pin (96).
  • the sensors (22A, 22B) may be directly connected to interface (30) of control system (100) or indirectly using an intermediary system (not shown), for instance a wireless emitter.
  • an intermediary system not shown
  • other types of communication link technologies may be used, such as, for example, optical.
  • non-articulated or articulated prosthetic foot may be used as well as long as the selected prosthetic foot provides approximately the same dynamical response as the ones mentioned here above. Nevertheless, an articulated foot offers the best performances.
  • the instrumented prosthetic foot (20) may further have an exposed metal or composite structure or it may have a cosmetic covering that gives it the appearance of a human ankle and foot.
  • the present invention is not limited to its use with the mechanical configuration illustrated in FIG. 1 or the control system (100) illustrated in FIG. 2. It may be used with a leg prosthesis having more than one joint. For instance, it may be used with a prosthesis having an ankle joint, a metatarsophalangeal joint or a hip joint in addition to a knee joint. Moreover, instead of a conventional socket a osseo-integrated devices could also be used, ensuring a direct attachment between the mechanical component of the prosthesis and the amputee skeleton. Other kinds of prostheses may be used as well.

Abstract

The present application discloses an instrument prosthetic foot (20) for use with an actuated leg prothesis (14) controlled by a controller, the instrumented prosthetic foot (20) comprising a connector to connect the instrumented prosthetic foot (20) to the leg prothesis (14), an ankle structure connected to the connector, a ground engaging member connected to the ankle, at least one sensor (22a, 22b, 24a, 24b, 26) for detecting changes in weight distribution along the foot, and an interface for transmitting signals from the sensor to the controller.

Description

INSTRUMENTED PROSTHETIC FOOT
BACKGROUND
As is well known to control engineers, the automation of complex mechanical systems is not something easy to achieve. Among such systems, conventional powered artificial limbs are notorious for having control problems. These conventional prostheses are equipped with basic controllers that artificially mobilize the joints without any interaction from the amputee and are only capable of generating basic motions. Such basic controllers do not take into consideration the dynamic conditions of the working environment, regardless the fact that the prosthesis is required to generate appropriate control within a practical application. They are generally lacking in predictive control strategies necessary to anticipate the artificial limb's response as well as lacking in adaptive regulation enabling the adjustment of the control parameters to the dynamics of the prosthesis. Because human limb mobility is a complex process including voluntary, reflex and random events at the same time, conventional prostheses do not have the capability to interact simultaneously with the human body and the external environment in order to have minimal appropriate functioning.
Accordingly, it is an object of the present application to obviate or mitigate some or all of the above disadvantages. SUMMARY
According to the present invention, there is provided an instrumented prosthetic foot for use with an actuated leg prosthesis controlled by a controller, the instrumented prosthetic foot comprising a connector to connect the instrumented prosthetic foot to the leg prosthesis, an ankle structure connected to the connector, a ground engaging member connected to the ankle, at least one sensor for detecting changes in weight distribution along the foot, and an interface for transmitting signals from the sensor to the controller. BRIEF DESCRIPTION OF THE FIGURES
Embodiments of the invention will be described by way of example only with reference to the accompanying drawings, in which:
FIG. 1 shows the lower body of an individual provided with a prosthesis and an instrumented prosthetic foot on one side and having a healthy leg on the other side.
FIG. 2 is a block diagram showing a control system for a prosthesis having an actuating mechanism.
FIG. 3 is a perspective view, from the front and slightly above, of a instrumented prosthetic foot.
FIG. 4 is an exploded perspective view of the instrumented prosthetic foot of FIG. 3.
FIG. 5 is a perspective view, from the front and slightly above, of an alternative embodiment of the instrumented prosthetic foot of FIG. 3.
FIG. 6 is an exploded perspective view of the instrumented prosthetic foot of FIG. 5.
FIG. 7 is a perspective view, from the front and slightly above, of another alternative embodiment of the instrumented prosthetic foot of FIG. 3
FIG. 8 is an exploded perspective view of the instrumented prosthetic foot of FIG. 7.
FIG. 9 is schematic view of forces exerted on a foot.
FIG. 10 is a perspective view, from the front and slightly above, of a further still alternative embodiment of the instrumented prosthetic foot of FIG. 3
FIG. 11 is an exploded perspective view of the instrumented prosthetic foot of FIG. 10. FIG. 12 is a perspective view, from the front and slightly above, of a yet further still alternative embodiment of the instrumented prosthetic foot of FIG. 3
FIG. 13 is an exploded perspective view of the instrumented prosthetic foot of FIG. 12.
FIG. 14 is a perspective view, from the front and slightly above, of a further alternative embodiment of the instrumented prosthetic foot of FIG. 3
FIG. 15 is an exploded perspective view of the instrumented prosthetic foot of FIG. 14.
DETAILED DESCRIPTION
The appended figures show a instrumented prosthetic foot (20) having sensors (22A, 22B) for use, in cooperation with possible additional sensors (24A, 24B, 26), with a control system (100) for controlling a prosthesis (14) having an actuating mechanism (16). It should be understood that the present invention is not limited to the illustrated implementation since various changes and modifications may be effected herein without departing from the scope of the appended claims.
Referring therefore to FIG. 1 an individual (10) has a pair of legs (26) and (28), one of which, (26), is amputated above the knee. A prosthesis (14) is attached to the leg (26) and includes an actuating mechanism (16), which may be either passive or active. An instrumented prosthetic foot (20) is attached to the prosthesis (14) and includes sensors (22A, 22B). Additional sensors (24A, 24B) are located on the healthy foot and additional sensors (26) located on the individual (10) and/or the prosthesis (14). A passive actuating mechanism may be generally defined as an electro-mechanical component that only absorbs mechanical energy in order to modify dynamics of mechanical joints of the prosthesis, while an active actuating mechanism may be generally defined as an electro-mechanical component that absorbs and supplies mechanical energy in order to set dynamics of mechanical joints of the prosthesis. An example of a passive actuating mechanism is described in U.S. patent application No. 09/767,367, filed January 22, 2001 , entitled "ELECTRONICALLY CONTROLLED PROSTHETIC KNEE". Examples of active actuating mechanisms are described in U.S. patent application No. 10/463,495 filed June 17, 2003, entitled "ACTUATED PROSTHESIS FOR ABOVE-KNEE AMPUTEES", by Stephane Bedard et al., the entire disclosure of which is hereby incorporated by reference herein.
The prosthesis (14) is controlled, as shown schematically in FIG. 2, by a basic control system (100) comprising sensors (22A, 22B, 24A, 24B, 26), connected through an interface (30) to a controller (40). The controller (40) provides signals to an actuating mechanism (16) in the prosthesis (14) , such as shown in FIG. 1. The purpose of the control system (100) is to provide the required signals for controlling the actuating mechanism (16). To do so, the control system (100) is interfaced with the amputee (10) using sensors (22A, 22B, 24A, 24B, 26) to ensure proper coordination between the amputee (10) and the movements of the prosthesis (14). The sensors (22A, 22B, 24A, 24B, 26) capture information, in real time, about the dynamics of the amputee's movement and provide that information to the controller (40) via the interface (30). The controller (40) then uses the information to determine the resistance to be applied to a joint, in the case of a passive actuating mechanism, or the joint trajectories and the required angular force or torque that must be applied by a joint, in the case of an active actuating mechanism, in order to provide coordinated movements.
The sensors (22A, 22B, 24A, 24B, 26) may include myoelectric sensors, neuro- sensors, kinematic sensors, kinetic sensors, strain gauges or plantar pressure sensors. Myoelectric sensors are electrodes used to measure the internal or the external myoelectrical activity of skeletal muscles. Neuro-sensors are electrodes used to measure the summation of one or more action potentials of peripheral nerves. Kinematic sensors are used to measure the position of articulated joints, the mobility speed or acceleration of lower extremities. Kinetic sensors are used to measure angular forces at articulated joints or reaction forces of lower extremities. Strain gages are used to measure the strain forces at a specific underfoot area. Plantar pressure sensors are used to measure the vertical plantar pressure of a specific underfoot area. Of course, additional types of sensors " which provide various information about dynamics of human locomotion may be used. For a given application, the use of sensors (22A, 22B, 24A, 24B, 26) is not restricted to a specific type of sensor, multiple types of sensors in various combinations may be used.
As illustrated in FIG. 1 , the sensors (22A, 22B, ) may comprise localized plantar pressure sensors located at spaced locations on the prosthetic foot (20) to measure the vertical plantar pressure of a specific underfoot area. Similarly, the plantar pressure sensors (24A, 24B) located on the side of the healthy foot may be provided at spaced locations in a custom-made insole, preferably in the form of a standard orthopaedic insole, that is modified to embed the two sensors (24A, 24B) for the measurement of two localized plantar pressures. The sensors (22A, 22B, 24A, 24B) are operable to measure the weight transfer along the foot as the individual moves which may be combined with other sensors (26) such as kinematic sensors to measure the angular speed of body segments of the lower extremities and kinematic sensors to measure the angle of the prosthesis (14) knee joint.
Each sensor (22A, 22B, 24A, 24B) may comprise a thin Force-Sensing Resistor (FSR) polymer cell directly connected to the interface (30) of the control system
(100) or indirectly using an intermediary system (not shown), for instance a wireless emitter. Of course, other types of communication link technologies may be used, such as, for example, optical. The FSR cell has a decreasing electrical resistance in response to an increasing force applied perpendicularly to the surface thereof. Each cell outputs a time variable electrical signal for which the intensity is proportional to the total vertical plantar pressure over its surface area.
The size and position of the plantar pressure sensors (22A, 22B, 24A, 24B) may be defined in accordance with the stability and the richness (intensity) of the localized plantar pressure signals provided by certain underfoot areas during locomotion. For example, it was found by experimentation that the heel and the toe regions are two regions of the foot sole where the Plantar Pressure Maximum Variation (PPMV) may be considered as providing a signal that is both stable and rich in information.
Accordingly, the controller (40) may use the data signals from the four localized plantar pressure sensors (22A, 22B, 24A, 24B), as well as the information gathered from the data signals of the other sensors (26) such as kinematic sensors, in order to decompose the locomotion of the individual (10) into a finite number of states, and generate the appropriate control signals for controlling the actuating mechanism (16) according to the locomotion. Of course, the controller (40) is not limited to the use of the preceding data signals. An example of a controller (40) and control system (100) using sensors comprising plantar pressure sensors as well as kinematic sensors is described in U.S. patent application No. 10/600,725 filed June 20, 2003, entitled "CONTROL SYSTEM AND METHOD FOR CONTROLLING AN ACTUATED PROSTHESIS", by Stephane Bedard, the entire disclosure of which is hereby incorporated by reference herein.
To facilitate the acquisition of the data in a repeatable and dependable manner, the sensors (22A, 22B) are incorporated in to the structure of the foot (20). An embodiment of the instrumented prosthetic foot (20) is shown in more detail in FIGS 3 and 4. The instrumented prosthetic foot (20) includes a foot plate (53), forming an elongated body, with a connector (51) at one end, a toe plate (55A) and a heel plate (55B) that is cantilevered from the foot plate (53). Such an arrangement is provided by, for example, a Vari-Flex® prosthetic foot from Ossur. Pressure sensors (22A, 22B) are located at longitudinally spaced locations on the underside of the foot plate (53) and heel plate (55) respectively. The sensors (22A, 22B) are covered by rigid plates (52A, 52B) and resilient pads (54A, 54B). The pressure sensors (22A, 22B) are located so as to be responsive to loads imposed on the instrumented prosthetic foot (20) at the regions corresponding to the toe area and the heel area respectively.
The rigid plates (52A, 52B) covering the sensors (22A, 22B), although not essential, help to optimize the pressure distribution on the entire surface of the sensors (22A, 22B) as well as inhibiting any shearing and may be made of 85A durometer polyurethane. Of course, other type of material may be used as well.
The pads (54A, 54B) wrap up the rigid plates (52A, 52B) and the sensors (22A, 22B), forming a ground engaging member, in order to optimize the contact between the instrumented prosthetic foot (20) and the ground. The pads (54A, 54B) may be made of 40A durometer polyurethane. Of course, other type of material may be used as well.
In operation, therefore, as the foot (20) traverses the ground, the force applied to the heel plate (55B) is measured by the sensor (22B) and a corresponding signal forwarded to the controller (40). The force applied to the toe plate (55A) is also measured by the sensor (22A) and the relative loading between the two locations is measured. As the foot (20) continues to traverse the ground, the force applied to the toe area increases and that at the heel decreases to provide a pair of signals from which the disposition of the leg may be determined and the appropriate control provided to the actuator (16).
An alternative embodiment of the instrumented prosthetic foot (20) is shown in FIGS 5 and 6. The instrumented prosthetic foot (20) includes connector (61), foot plate (63), toe plate (64A) and heel plate (64B), such as provided by, for example, a Vari-Flex® prosthetic foot from Ossur. Pressure sensors (22A, 22B) are located between the foot plate (63) and rigid plates (62A, 62B). The pressure sensors (22A, 22B) are located so as to be responsive to load imposed on the instrumented prosthetic foot (20) at the regions corresponding to the toe area and the heel area respectively. More specifically, pressure sensor (22A) is sandwiched between a pair of rigid plates (62A), which in turn are positioned between the heel plate (64B) and the foot plate (63). Pressure sensor (22B) is sandwiched between a pair of rigid plates (62B), which in turn are positioned between the foot plate (63) and the connector (61 ).
As for the previous embodiment, rigid plates (62A, 62B) covering the sensors
(22A, 22B), although not essential, help to optimize the pressure distribution on the entire surface of the sensors (22A, 22B) as well as inhibiting any shearing and may be made of 85A durometer polyurethane. Of course, other type of material may be used as well.
Another alternative embodiment of the instrumented prosthetic foot (20) is shown in FIGS 7 and 8. The instrumented prosthetic foot (20) includes connector (71), top foot plate (75), foam cushion core (73) and bottom foot plate (74), such as provided by, for example, a LP Talux® prosthetic foot from Ossur. Pressure sensors (22A, 22B) are sandwiched between pairs of rigid plates (72A, 72B). The pressure sensors (22A, 22B) are located so as to be responsive to load imposed on the instrumented prosthetic foot (20) at the regions corresponding to the toe area and the heel area respectively. More specifically, pressure sensor (22A) is sandwiched between a pair of rigid plates (72A), which in turn are positioned within gap (76A), which is located between a bottom foot plate (74) and a foam cushion core (73). Pressure sensor (22B) is sandwiched between a pair of rigid plates (72B), which in turn are positioned within gap (76B), which is located within the foam cushion core (73).
Again, as for the previous embodiments, rigid plates (72A, 72B) covering the sensors (22A, 22B), although not essential, help to optimize the pressure distribution on the entire surface of the sensors (22A, 22B) as well as preventing any shearing and may be made of 85A durometer polyurethane. Of course, other type of material may be used as well.
In the previous embodiments, the force (or pressure) at the toe and heel areas, F_toe and F_heel respectively, was obtained by positioning pressure sensors (22A, 22B) directly at those areas. More specifically, referring to FIG. 9, F_toe and FJieel were obtained as follows: F_toe = F_toe_meas Equation 1
F_heel = F_heel_meas Equation 2
In other possible embodiments of the instrumented prosthetic foot (20), sensors (22A, 22B) may not be restricted to being positioned directly at the toe and heel areas, the equivalent information may be obtained by measuring the equivalent torque at the ankle and the axial force at the connector of the instrumented prosthetic foot (20). F_toe and F_heel may be defined in terms of the torque measured at the ankle, M_ankle_meas, and the force measured at the connector, F_conn_meas, using the following equations:
_ . M ankle meas + (F conn meas - l heel) _ F toe = —= = — = = = Equation 3 (l_heel + l_toe) M
._ . . -M ankle meas + (F conn meas - l toe) _ F heel = = = ^-= = = Equation 4 (l_heel + l_toe) where l_heel is the distance between the center of the connector and the center of the heel area; l_toe is the distance between the center of the connector and the center of the toe area.
Following the previous discussion about the locations of sensors (22A, 22B), a further alternative embodiment of the instrumented prosthetic foot (20) is shown in FIGS 10 and 11. The instrumented prosthetic foot (20) includes connector (81 ), foot plate (83), toe plate (84A) and heel plate (84B), such as provided by, for example, a Vari-Flex® prosthetic foot from Ossur, and load cells (22A, 22B). Load cells (22A, 22B) are located below connector (91), load cell (22A) being slightly biased towards the toe area of the foot and load cell (22B) being slightly biased towards the heel area. Since the sensors (22A, 22B) are not located directly at the toe and heel areas, Equation 3 and Equation 4 may be used, for example by controller (40), to compute the equivalent pressures at the toe and heel areas by defining the equivalent torque at the ankle and the axial force at connector (81 ) as follows: F_conn_meas = F_22B + F_22A Equation 5 M_ankle_meas = F_22B -l_22B -F_22A -l _22A Equation 6 where
F_22B is the force measured at sensor 22B;
F_22A is the force measured at sensor 22A; l_22B is the distance between the center of the connector (81 ) and the center of sensor 22B; l_22A is the distance between the center of the connector (81 ) and the center of sensor 22A.
In the previous embodiments of the instrumented prosthetic foot (20), the force (or pressure) at the toe and heel areas, F_toe and F_heel respectively, was obtained either by positioning pressure sensors (22A, 22B) directly at those areas or by positioning pressure sensors or load cells (22A, 22B) in other areas and obtaining the equivalent information by computing the equivalent torque at the ankle and the axial force at the connector. Other types of sensors may also be used to obtain the equivalent torque at the ankle and the axial force at the connector. Such an example is illustrated by a further still embodiment of the instrumented prosthetic foot (20), which is shown in FIGS 12 and 13. The instrumented prosthetic foot (20) includes connector (91 ), mounted on pivoting ankle (93). Bumpers (92A, 92B) are positioned between the pivoting ankle (93) and rocker plate (95) located on a foot plate (94). The pivoting ankle (93) is connected to the rocker plate (95) by a pivot pin (96). Such an arrangement is provided by, for example, an Elation® prosthetic foot from Ossur. A load cell (22A) and an optical encoder (22B). are incorporated into the foot (20) to provide measurement of the distribution of forces along the foot (20). Load cell (22A) is positioned between connector (91 ) and pivoting ankle (93). Optical encoder (22B) comprises reader (221) and disk (223). Reader (221) is located on pivoting ankle (93) while disk (223) is located on rocker plate (95) and encircles pivot pin (96). Once again, Equation 3 and Equation 4 may be used, for example by controller (40), to compute the equivalent pressures at the toe and heel areas by defining the equivalent torque at the ankle and the axial force at connector (91) as follows:
F_conn_meas = F_22A Equation 7
M_ankle_meas = R_ankle_meas -R_const Equation 8 where
F_22A is the force measured at sensor 22A;
R_ankle_meas is the rotation measurement of pivoting an kle (93) about pivot pin (96) as measured by optical encoder (22B);
R_const is a constant associated with the resistance of bumpers (92A, 92B) to compression, which constant varies depending in the material used.
A yet further alternative embodiment of the instrumented prosthetic foot (20) is shown in FIGS 14 and 15. The instrumented prosthetic foot (20) includes connector (101 ), mounted on pivoting ankle (103). Bumpers (102A, 1O2B) are positioned between the pivoting ankle (103) and rocker plate (105) located on a foot plate (104). The pivoting ankle (103) is connected to the rocker plate (105) by a pivot pin (106). Such an arrangement is provided by, for example, an Elation® prosthetic foot from Ossur. Pressure sensors (22A, 22B) and load cell (22C) are incorporated into the foot (20) to provide measurement of the distribution of forces along the foot (20). Pressure sensor (22A) is positioned between rocker plate (85) and bumper (82A) while pressure sensor (22B) is positioned between rocker plate (85) and bumper (82B). A load cell (22C) is positioned between connector (91) and pivoting ankle (93).
In this embodiment, Equation 6 is used to compute the equivalent torque at the ankle, while the axial force at connector (101) is computed using the following equation: F_conn_meas = F_22C Equation 9
Load cell (22C) is required to compute the axial force at connector (101 ) since when there is no torque at the ankle, i.e. the wearer of the prosthesis is standing still, the axial force is being exerted in its entirety onto pivot pin (96).
In all of the described embodiments, the sensors (22A, 22B) may be directly connected to interface (30) of control system (100) or indirectly using an intermediary system (not shown), for instance a wireless emitter. Of course, other types of communication link technologies may be used, such as, for example, optical.
Other types of non-articulated or articulated prosthetic foot may be used as well as long as the selected prosthetic foot provides approximately the same dynamical response as the ones mentioned here above. Nevertheless, an articulated foot offers the best performances. The instrumented prosthetic foot (20) may further have an exposed metal or composite structure or it may have a cosmetic covering that gives it the appearance of a human ankle and foot.
It should be noted that the present invention is not limited to its use with the mechanical configuration illustrated in FIG. 1 or the control system (100) illustrated in FIG. 2. It may be used with a leg prosthesis having more than one joint. For instance, it may be used with a prosthesis having an ankle joint, a metatarsophalangeal joint or a hip joint in addition to a knee joint. Moreover, instead of a conventional socket a osseo-integrated devices could also be used, ensuring a direct attachment between the mechanical component of the prosthesis and the amputee skeleton. Other kinds of prostheses may be used as well.

Claims

WHAT IS CLAIMED IS:
1. An instrumented prosthetic foot for use with an actuated leg prosthesis controlled by a controller, the instrumented prosthetic foot comprising: an elongated body having a top and a bottom part; a connector to connect the instrumented prosthetic foot to the leg prosthesis, the connector being attached to the top part of the elongated body; a ground engaging member attached to the bottom part of the elongated body; at least one sensor for detecting changes in weight distribution along the foot; and an interface for transmitting signals from the sensor to the controller.
2. An instrumented prosthetic foot according to claim 1 , wherein: the ground engaging member includes a pair of basic underfoot locations, the first region corresponding to the heel area of the human foot and second region corresponding to the toe area of the human foot.
3. An instrumented prosthetic foot according to claim 2, wherein: at least two sensors are provided, one of the sensors being associated with each basic underfoot locations of the ground engaging member.
4. An instrumented prosthetic foot according to claim 3, wherein: the sensors include a strain sensor to measure the strain applied at a corresponding basic underfoot location of the ground engaging member.
5. An instrumented prosthetic foot according to claim 3, wherein: the sensors include a pressure sensor to measure the pressure applied at a corresponding basic underfoot location of the ground engaging member.
6. An instrumented prosthetic foot according to claim 3, wherein: the sensors include a load cell to measure the pressure applied at a corresponding basic underfoot location of the ground engaging member.
7. An instrumented prosthetic foot according to claim 3, wherein: the sensors are positioned under the ground engaging member.
8. An instrumented prosthetic foot according to claim 3, wherein: the sensors are positioned between the ground engaging member and the elongated body.
9. An instrumented prosthetic foot according to claim 3, wherein: the sensors are positioned between the elongated body and the connector.
10. An instrumented prosthetic foot according to claim 5, wherein: the pressure sensor is a force-sensing resistor.
11. An instrumented prosthetic foot according to claim 5, further comprising: a rigid plate placed on at least one side of the sensor.
12. An instrumented prosthetic foot according to claim 11 , further comprising: a resilient pad covering the rigid plate and the sensor.
13. An instrumented prosthetic foot according to claim 1 , further comprising: an ankle structure pivotally connecting the elongated body to the connector.
14. An instrumented prosthetic foot according to claim 13, wherein: at least two sensors are provided, the sensors including two load cells positioned between the connector and the ankle structure.
15. An instrumented prosthetic foot according to claim 13, wherein: at least two sensors are provided, the sensors including an optical encoder and a load cell, the optical encoder being positioned on the ankle structure about its pivot axis with the elongated body and the load cell being positioned between the ankle structure and the connector.
16. An instrumented prosthetic foot according to claim 1 , wherein: the interface for transmitting signals from the sensor to the controller is a wired connection.
17. An instrumented prosthetic foot according to claim 1 , wherein: the interface for transmitting signals from the sensor to the controller is a wireless connection.
18. An instrumented prosthetic foot according to claim 1 , further comprising: means for removably connecting the instrumented prosthetic foot to the leg prosthesis.
PCT/CA2003/001802 2003-11-18 2003-11-18 Instrumented prosthetic foot WO2005048887A1 (en)

Priority Applications (8)

Application Number Priority Date Filing Date Title
EP03776700A EP1684676A1 (en) 2003-11-18 2003-11-18 Instrumented prosthetic foot
CA2543061A CA2543061C (en) 2003-11-18 2003-11-18 Instrumented prosthetic foot
KR1020067009718A KR101007946B1 (en) 2003-11-18 2003-11-18 Instrumented prosthetic foot
CN2003801107082A CN1878517B (en) 2003-11-18 2003-11-18 Instrumented prosthetic foot
JP2005510677A JP4320017B2 (en) 2003-11-18 2003-11-18 Instrumented artificial leg
PCT/CA2003/001802 WO2005048887A1 (en) 2003-11-18 2003-11-18 Instrumented prosthetic foot
AU2003286026A AU2003286026B2 (en) 2003-11-18 2003-11-18 Instrumented prosthetic foot
AU2010200238A AU2010200238B2 (en) 2003-11-18 2010-01-21 Instrumented Prosthetic Foot

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PCT/CA2003/001802 WO2005048887A1 (en) 2003-11-18 2003-11-18 Instrumented prosthetic foot

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JP (1) JP4320017B2 (en)
KR (1) KR101007946B1 (en)
CN (1) CN1878517B (en)
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CA (1) CA2543061C (en)
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US7347877B2 (en) * 2004-05-28 2008-03-25 össur hf Foot prosthesis with resilient multi-axial ankle
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US8858648B2 (en) 2005-02-02 2014-10-14 össur hf Rehabilitation using a prosthetic device
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US9717606B2 (en) 2005-04-19 2017-08-01 össur hf Combined active and passive leg prosthesis system and a method for performing a movement with such a system
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US8961618B2 (en) 2011-12-29 2015-02-24 össur hf Prosthetic foot with resilient heel
US10369019B2 (en) 2013-02-26 2019-08-06 Ossur Hf Prosthetic foot with enhanced stability and elastic energy return
US9561118B2 (en) 2013-02-26 2017-02-07 össur hf Prosthetic foot with enhanced stability and elastic energy return
US11285024B2 (en) 2013-02-26 2022-03-29 Össur Iceland Ehf Prosthetic foot with enhanced stability and elastic energy return
US11147692B2 (en) 2014-06-30 2021-10-19 Össur Iceland Ehf Prosthetic feet and foot covers
US10821007B2 (en) 2016-12-01 2020-11-03 Össur Iceland Ehf Prosthetic feet having heel height adjustability
US11771572B2 (en) 2016-12-01 2023-10-03 Össur Iceland Ehf Prosthetic feet having heel height adjustability
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AU2003286026A1 (en) 2005-06-08
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JP4320017B2 (en) 2009-08-26
CN1878517A (en) 2006-12-13
CN1878517B (en) 2010-09-01
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CA2543061C (en) 2012-01-24
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AU2010200238B2 (en) 2013-08-01
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