JP4320017B2 - Instrumented artificial leg - Google Patents

Description

  The present invention relates to an instrumented prosthesis.

  As is well known to control specialists, automation of complex mechanical systems is not easily possible. Among such systems, the conventional power prosthesis is well known for its various control problems. Such a prosthesis includes a basic controller that artificially moves the joint without interaction from the amputee and only allows basic movement. However, such a basic controller does not take into account the dynamic conditions of such a work environment, despite the fact that the prosthesis may require control suitable for the actual application. Such basic controllers generally lack the predictive control strategy necessary to predict prosthetic response, and lack adaptive adjustments that allow adjustment of control parameters to prosthetic dynamics. Because the human leg motility is a complex process involving simultaneous voluntary, reflexive and random events, conventional prosthetic limbs can be used in the human body and the external environment to meet the lowest appropriate function. Does not have the ability to interact simultaneously.

US patent application no. 09 / 767,367 (filed on January 22, 2001) US patent application no. 10 / 463,495 (filed on June 17, 2003) US patent application no. 10 / 600,725 (filed on June 20, 2003)

  Accordingly, one object of the present invention is to avoid or mitigate some or all of the above-mentioned drawbacks.

  In accordance with the present invention, an instrumented prosthesis is provided for use with the operation of a prosthesis controlled by a controller. That is, the instrumented artificial leg includes a connector for connecting the instrumented artificial leg to the artificial limb, an ankle (ankle joint) structure connected to the connector, a ground engaging member connected to the ankle structure, and a foot. It is characterized by comprising at least one sensor for detecting a change in the weight distribution along, and an interface for transmitting a signal from this sensor to the controller.

Specific examples of the present invention will be described below with reference to the drawings.
The accompanying drawings show an instrumented prosthesis (20) with sensors (22A, 22B), which cooperate with possible additional sensors (24A, 24B, 26) to activate the actuation mechanism (16). Used with a control system (100) for controlling a prosthetic limb (14). It should be understood that the present invention should not be limited to the illustrated embodiments, and that various modifications and improvements can be made without departing from the scope of the appended claims.

  Referring to FIG. 1, an individual (10) has a pair of legs (26) and (28), one of which (26) is cut at a portion above the knee. A prosthetic limb (14) is attached to the leg (26). The prosthesis (14) includes a passive or active actuation mechanism (16). The instrumented prosthesis (20) is attached to the prosthesis (14) and includes sensors (22A, 22B). In addition, additional sensors (24A, 24B) are placed on the healthy feet, and additional sensors (26) are placed on the individual (10) and / or the prosthetic limb (14). A passive actuation mechanism can generally be defined as an electromechanical member that only changes mechanical dynamics of a prosthetic limb simply by absorbing mechanical energy. On the other hand, an active actuation mechanism can generally be defined as an electromechanical member that absorbs and supplies mechanical energy and sets the mechanical joint dynamics of the prosthesis.

  One example of a passive actuation mechanism is described in Patent Document 1 (which is incorporated herein by reference in its entirety) as an electric knee prosthesis. One example of an active actuation mechanism is described in the above-mentioned patent document 2 (incorporated herein by reference in its entirety) as an actuating prosthesis for a patient with a thigh cut.

  The prosthesis (14) has a basic control system (100) with sensors (22A, 22B, 24A, 24B, 26) connected to the controller (40) via the interface (30), as schematically shown in FIG. ). This controller (40) provides a signal to the actuation mechanism (16) in the prosthesis (14) as shown in FIG. The purpose of the control system (100) is to provide the necessary signals to control the actuation mechanism (16). Therefore, the control system (100) is connected to the amputated patient (10) via the interface using the sensors (22A, 22B, 24A, 24B, 26), and the movement of the amputated patient (10) and the prosthetic limb (14) To ensure the correct harmony between. Sensors (22A, 22B, 24A, 24B, 26) capture information about the dynamics of movement of the amputee (10) in real time and provide that information to the controller (40) via the interface (30). It is supposed to be. This controller (40) then uses that information to determine the resistance applied to the joint in the case of a passive actuation mechanism, and in the case of an active actuation mechanism, the joint trajectory and the required angular force to be applied by the joint. Alternatively, the angular torque is determined and a harmonious movement is provided.

  These sensors (22A, 22B, 24A, 24B, 26) include myoelectric sensors, nerve sensors, motion sensors, dynamic sensors, strain gauges, plantar pressure sensors, and the like. A myoelectric sensor is an electrode used to measure the inner or outer myoelectric activity of skeletal muscle. A neural sensor is an electrode used to measure the sum of one or more action potentials of peripheral nerves. Motion sensors are used to measure the position of joints connected, speed of movement, or acceleration of the lower limbs. A dynamic sensor is used to measure angular force at the connected joint or reaction force of the lower limb. A strain gauge is used to measure the strain force in a specific area under the foot. The plantar pressure sensor is used to measure the vertical plantar pressure in a specific area under the foot. Of course, other types of sensors that provide various information about the dynamics of human movement motion may be used. Depending on the application, these sensors (22A, 22B, 24A, 24B, 26) are not limited to specific types of sensors, and many types of sensors may be used in various combinations.

  As shown in FIG. 1, the sensors (22A, 22B) consist of local plantar pressure sensors that are spaced apart from each other on the prosthetic foot (20) to measure the vertical plantar pressure in a specific area under the foot. It comes to measure. Similarly, a plantar pressure sensor (24A, 24B) is placed on a healthy foot side and is a standard orthopedic skin that has been modified to embed a custom skin (preferably two sensors (24A, 24B)) ) Separated from each other and is adapted to measure two local plantar pressures. These sensors (22A, 22B, 24A, 24B) are operable to measure weight movement along the foot when the individual moves, and they are combined with other sensors (26) such as motion sensors. The angular velocity of the body part of the lower limb is measured, and the angle of the artificial limb (14) with respect to the knee joint is measured via a motion sensor.

  Each of these sensors (22A, 22B, 24A, 24B) may consist of a thin load sensing resistor (FSR) polymer cell, which is directly connected to the interface (30) of the control system (100). Or indirectly connected to the interface (30) using a relay system (not shown) such as a wireless emitter. Of course, in this case, other types of communication connection techniques, such as optical means, can also be used. The FSR cell has an electrical resistance that decreases in response to an increase in stress applied perpendicular to its surface. Each cell outputs a time-varying electrical signal that is proportional to the total vertical plantar pressure on its surface area. The size and position of these plantar pressure sensors (22A, 22B, 24A, 24B) are defined according to the stability and concentration (intensity) of the local plantar pressure signal provided by a certain foot region during walking. . For example, the heel and toe portions have been experimentally found to be two regions of the sole where the plantar pressure maximum change (PPMV) is believed to provide a stable and informative signal. .

  Thus, the controller (40) collects information gathered from data signals from four localized plantar pressure sensors (22A, 22B, 24A, 24B) as well as data signals from other sensors (26) such as motion sensors. In use, the gait of the individual (10) is broken down into a finite number of states and appropriate control signals are generated to control the actuation mechanism (16) according to this gait. Of course, the controller (40) is not limited to the one using the data signal described above.

  An example of a controller (40) and a control system (100) using sensors including a plantar pressure sensor and a motion sensor is disclosed in Patent Document 3 (the entirety of which is referred to as a reference) as a control system and a control method for controlling an operating artificial foot It shall be incorporated herein).

  Sensors (22A, 22B) are incorporated into the structure of the prosthesis (20) to facilitate repeated data acquisition and in a reliable manner. An example of an instrumented prosthesis (20) is shown in more detail in FIGS. This mechanized artificial leg (20) was cantilevered from a foot plate (53) forming a long body having a connector (51) at one end, a toe plate (55A), and the foot plate (53). Heel plate (55B). Such a configuration is provided, for example, as a prosthetic leg, Vari-Flex (registered trademark) by Ossur. The pressure sensors (22A, 22B) are spaced apart in the longitudinal direction on the bottom surfaces of the foot plate (53) and the heel plate (55B), respectively. These sensors (22A, 22B) are covered with hard plates (52A, 52B) and elastic pads (54A, 54B). Each of these pressure sensors (22A, 22B) is arranged to respond to a load applied on the instrumented prosthesis (20) in an area corresponding to the toe and heel areas.

  Hard plates (52A, 52B) covering these sensors (22A, 22B) help optimize the pressure distribution over the entire surface of the sensors (22A, 22B), but are not essential, while at the same time suppressing shear To do. The hard plates (52A, 52B) can be made from polyurethane with a durometer hardness of 85A. Of course, other materials can be used.

  Pads (54A, 54B) wrap around rigid plates (52A, 52B) and sensors (22A, 22B) to form a ground engaging member and optimize contact between the instrumented prosthesis (20) and the ground. . These pads (54A, 54B) can be made from polyurethane having a durometer hardness of 40A. Of course, other materials can be used.

  In operation, when the prosthetic leg (20) crosses the ground, the stress applied to the heel plate (55B) is measured by the sensor (22B) and a corresponding signal is transmitted to the controller (40). The stress applied to the toe plate (55A) is measured by the sensor (22A) and the relative load between these two regions is measured. As the prosthetic leg (20) continues to traverse the ground, the force applied to the toe area increases, the force at the heel decreases, and a pair of signals is provided to determine leg placement and appropriate control. Is provided to the actuation mechanism (16).

  Another embodiment of an instrumented prosthesis (20) is shown in FIGS. The instrumented prosthesis (20) includes a connector (61), a foot plate (63), a toe plate (64A), and a heel plate (64B). This configuration is provided, for example, as a prosthetic leg from Ossur, Vari-Flex (registered trademark). Pressure sensors (22A, 22B) are disposed between the foot plate (63) and the hard plates (62A, 62B). The pressure sensors (22A, 22B) are respectively disposed in the toe area and the area corresponding to the heel area so as to respond to the load applied on the instrumented prosthesis (20). More specifically, the pressure sensor (22A) is disposed between the pair of hard plates (62A), and as a result, is disposed between the heel plate (64B) and the foot plate (63). The pressure sensor (22B) is disposed between the pair of hard plates (62B), and as a result, is disposed between the foot plate (63) and the connector (61).

  Similar to the previous embodiment, the rigid plates (62A, 62B) covering the sensors (22A, 22B) are not essential, but optimize the pressure distribution over the entire surface of the sensors (22A, 22B). And at the same time suppresses shearing. The hard plates (62A, 62B) can be made from polyurethane with a durometer hardness of 85A. Of course, other materials can be used.

    Yet another embodiment of an instrumented prosthesis (20) is shown in FIGS. The instrumented prosthesis (20) includes a connector (71), a top foot plate (75), a foam cushion core (73), and a bottom foot plate (74). This configuration is provided, for example, as an artificial leg, LP Talux (registered trademark) by Ossur. The pressure sensors (22A, 22B) are disposed between a pair of hard plates (72A, 72B). The pressure sensors (22A, 22B) are respectively disposed in the toe area and the area corresponding to the heel area so as to respond to the load applied on the instrumented prosthesis (20). More specifically, the pressure sensor (22A) is disposed between the pair of hard plates (72A), and as a result, the gap (76A) between the bottom foot plate (74) and the bubble cushion core (73) is arranged. ). The pressure sensor (22B) is disposed between the pair of hard plates (72B), and as a result, is disposed in the gap (76B) located in the bubble cushion core (73).

  Again, as in the previous embodiment, the rigid plates (72A, 72B) covering the sensors (22A, 22B) are not essential but optimize the pressure distribution over the entire surface of the sensors (22A, 22B). It helps to reduce shearing at the same time. The hard plates (72A, 72B) can be made from polyurethane with a durometer hardness of 85A. Of course, other materials can be used.

In the foregoing embodiment, the force (or pressure) at the toe and heel areas (ie, F _- toe and F _- heel) directly attach the pressure sensors (22A, 22B) to these areas. Obtained by placing. More specifically, referring to FIG. 9, F _- toe (toe) and F _- heel (heel) were obtained as follows.

F _- toe = F _- toe _- meas (measured value) Equation 1
F _- heel = F _- heel _- meas (measured value) Equation 2

Other possible embodiments of the instrumented prosthesis (20) are not limited to placing the sensors (22A, 22B) directly in the toe and heel areas. Equivalent information can be obtained by measuring the equivalent torque at the ankle and the axial force at the connector of the instrumented prosthesis (20). Replace F _- toe (toe) and F _- heel (heel) with the torque measured at the heel (M _- ankle _- meas) and the force measured at the connector (F _- conn _- meas) using the following equation: Can be defined.

F ₋ toe = {M ₋ ankle ₋ meas + (F ₋ conn ₋ meas · I ₋ heel)} / (I ₋ heel + I ₋ toe)
Formula 3
F ₋ heel = {− M ₋ ankle ₋ meas + (F ₋ conn ₋ meas · I ₋ toe)} / (I ₋ heel + I ₋ toe)
Formula 4
Where I _- heel is the distance between the center of the connector and the center of the heel area; I _- toe is the distance between the center of the connector and the center of the toe area.

  Following the previous description of the position of the sensors (22A, 22B), yet another embodiment of the instrumented prosthesis (20) is shown in FIGS. The instrumented prosthetic foot (20) includes a connector (81), a foot plate (83), a toe plate (84A), and a heel plate (84B). This configuration is provided, for example, as a prosthetic leg from Ossur, Vari-Flex (registered trademark). The instrumented prosthesis (20) further includes load cells (load detectors) (22A, 22B). These load cells (22A, 22B) are arranged under the connector (81). That is, the load cell (22A) is slightly biased toward the toe area and the load cell (22B) is slightly biased toward the heel area. Since the pressure sensors (22A, 22B) are not located directly in the toe and heel areas, equations 3 and 4 can be used, for example, by the controller (40), with an equivalent torque at the ankle and a connector (81) Can be calculated by defining the axial force of

F ₋ conn ₋ meas = F ₋ 22B + F ₋ 22A Equation 5
M ₋ ankle ₋ meas = F ₋ 22B · I ₋ 22B−F ₋ 22A · I ₋ 22A Equation 6
here,
F _- 22B is the force measured by sensor 22B;
F _- 22A is the force measured by sensor 22A;
I _- 22B is the distance between the connector (81) and the center of the sensor 22B;
I _- 22A is the distance between the connector (81) and the center of the sensor 22A.

In the previous embodiment of the instrumented prosthesis (20), the force (pressure) in the toe and heel areas, ie, F _- toe and F _- heel, respectively, place the pressure sensors (22A, 22B) directly into these areas. Obtained by placing or calculating these equivalent pressure sensors or load cells (22A, 22B) in other areas and calculating the equivalent torque at the ankle and the axial force at the connector to obtain equivalent information. is there. Other types of sensors can also be used to obtain the equivalent torque at the ankle and the axial force at the connector. Such an example is shown in a further embodiment for an instrumented prosthesis (20), ie FIGS. The instrumented prosthesis (20) includes a connector (91) attached to a pivoting ankle (93). Bumpers (92A, 92B) are disposed between the pivoting ankle (93) and the rocker plate (95) disposed on the foot plate (94). The pivot ankle (93) is connected to the rocker plate (95) by a pivot pin (96). This configuration is provided, for example, as an artificial leg, Elation (registered trademark) by Ossur. A load cell (22A) and an optical encoder (22B) are incorporated into the prosthetic foot (20) to allow measurement of the force distribution along the prosthetic foot (20). The load cell (22A) is disposed between the connector (91) and the pivoting ankle (93). The optical encoder (22B) includes a reading device (221) and a disk (223). The reader (221) is disposed on the pivot ankle (93) and the disc (223) is disposed on the rocker plate (95) and surrounds the pivot pin (96). Again, equations 3 and 4 are used, for example, by controller (40) to define the equivalent pressure at the toe and heel area, the equivalent torque at the ankle and the axial force at connector (81) as follows: Can be calculated.

F _- conn _- meas = F _- 22A Equation 7
M ₋ ankle ₋ meas = R ₋ ankle ₋ meas · R ₋ const Eq. 8
here,
F _- 22A is the force measured by sensor 22A;
R _- ankle (ankle) _- meas is the rotation measure of pivoting ankle (93) about the pivot pin (96), as measured by an optical encoder (22B);
R _- const is a constant related to the resistance of the bumper (92A, 92B) to compression, and this constant varies depending on the material used.

  Yet another embodiment of an instrumented prosthesis (20) is shown in FIGS. The instrumented prosthesis (20) includes a connector (101) mounted on a pivoting ankle (103). The bumpers (102A, 102B) are disposed between the pivoting ankle (103) and the rocker plate (105) provided on the foot plate (104). The pivoting ankle (103) is connected to the rocker plate (105) by a pivot pin (106). This configuration is provided, for example, as an artificial leg, Elation (registered trademark) by Ossur. The pressure sensors (22A, 22B) and the load cell (22C) are incorporated in the prosthetic foot (20) and allow measurement of the force distribution along the prosthetic foot (20). The pressure sensor (22A) is disposed between the rocker plate (85) and the bumper (82A), and the pressure sensor (22B) is disposed between the rocker plate (85) and the bumper (82B). The load cell (22C) is disposed between the connector (91) and the pivoting ankle (93).

  In this example, Equation 6 is used to calculate the equivalent torque at the ankle and the axial force at the connector (101) is calculated using the following equation:

F _- conn _- meas = F _- 22C Equation 9

  The load cell (22C) is required to calculate the axial force at the connector (101). This is because when the torque is zero at the ankle, i.e. when the prosthetic wearer is stationary, the axial force is exerted entirely on the pivot pin (96).

  In all of the previous embodiments, the sensors (22A, 22B) may be directly connected to the interface (30) of the control system (100) or a relay system (not shown) such as a wireless emitter, for example. And may be indirectly connected to the interface (30). Of course, in this case, other types of communication connection techniques, such as optical means, can also be used.

  Other types of articulated or articulated prostheses can be used as well as long as the selected prosthesis provides a dynamic response similar to that described above. However, articulated prostheses can provide the best performance. The instrumented prosthesis (20) may further have an exposed metal or composite structure, or may have a cosmetic cover that provides the appearance of a human ankle and foot.

  It should be noted that the present invention is not limited to use with a mechanical structure as shown in FIG. 1 or a control system (100) as shown in FIG. That is, the present invention can be used with a prosthesis having a plurality of joints. For example, in addition to the knee joint, it can be used with a prosthesis having an ankle joint, a metatarsal joint, or a hip joint. Furthermore, instead of a conventional socket, a bone coalescing device can also be used, thereby ensuring a direct joint between the mechanical member of the prosthesis and the cutting skeleton. Other types of prostheses can be used as well.

It is a perspective view which shows the lower body of the individual who has a prosthesis, Comprising: An instrumentation artificial leg is mounted | worn with one leg, and the other leg is healthy. The block diagram which shows the control system for artificial limbs which has an action mechanism. The perspective view seen from the front slightly above the instrumentation artificial leg. The disassembled perspective view of the instrumentation artificial leg of FIG. It is the perspective view of other Examples of the instrumentation artificial leg of FIG. 3, Comprising: The figure seen from the front slightly upper direction. The disassembled perspective view of the instrumentation artificial leg of FIG. It is the perspective view of other Example of the instrumentation artificial leg of FIG. 3, Comprising: The figure seen from the front slightly above. The disassembled perspective view of the instrumentation artificial leg of FIG. The figure which shows typically the force added to the leg | foot. It is the perspective view of other Example of the instrumentation artificial leg of FIG. 3, Comprising: The figure seen from the front slightly above. The disassembled perspective view of the instrumentation artificial leg of FIG. It is the perspective view of other Example of the instrumentation artificial leg of FIG. 3, Comprising: The figure seen from the front slightly above. The disassembled perspective view of the instrumentation artificial leg of FIG. It is the perspective view of other Example of the instrumentation artificial leg of FIG. 3, Comprising: The figure seen from the front slightly above. The disassembled perspective view of the instrumentation artificial leg of FIG.

Explanation of symbols

10 Individuals 14 Prosthetic leg 16 Actuation mechanism 20 Instrumentation artificial leg 22A, 22B Sensor 24A, 24B, 26 Sensor 26, 28 Leg 30 Interface 40 Controller 51, 61, 71, 91 Connector 53, 63, 94 Foot plate 55A, 64A Toe plate 55B , 64B Heel plate 72A, 72B Hard plate 73 Bubble cushion core 74 Bottom foot plate 92A, 92B Bumper 93 Pivot ankle 95 Rocker plate 96 Pivot pin 100 Control system 221 Reader 223 Disc

Claims (18)

An instrumented prosthesis used with the operation of a prosthesis controlled by a controller,
An elongated body having a top and a bottom;
A connector for connecting an instrumented prosthesis to a prosthesis, attached to the top of the elongate body;
A ground engaging member attached to the bottom of the elongate body;
At least one sensor for detecting a change in weight distribution along the foot;
An interface for transmitting signals from the sensor to the controller;
Instrumented artificial leg.   The ground engaging member includes a pair of basic foot regions, wherein the first region corresponds to a heel region of a human foot and the second region corresponds to a toe region of a human foot. The instrumental prosthesis according to 1.   3. The instrumented prosthesis of claim 2, wherein at least two sensors are provided, one of which is associated with each of the basic foot regions of the ground engaging member.   The instrumented prosthetic foot of claim 3, wherein the sensor includes a strain sensor for measuring strain applied to a corresponding basic foot region of the ground engaging member.   The instrumented prosthetic foot of claim 3, wherein the sensor includes a strain sensor for measuring pressure applied to a corresponding basic foot region of the ground engaging member.   The instrumented prosthetic foot of claim 3, wherein the sensor includes a load cell for measuring a load applied to a corresponding basic foot region of the ground engaging member.   The instrumented prosthetic foot according to claim 3, wherein the sensor is disposed below the ground engaging member.   The instrumented artificial leg according to claim 3, wherein the sensor is disposed between the ground engaging member and the elongated body.   The instrumented prosthetic foot according to claim 3, wherein the sensor is disposed between the elongated body and the connector.   The instrumented artificial leg according to claim 5, wherein the pressure sensor is a load detection resistor.   6. The instrumented prosthetic foot according to claim 5, further comprising a rigid plate disposed on at least one side of the sensor.   The instrumented prosthesis according to claim 11, further comprising an elastic pad that covers the hard plate and the sensor.   The instrumented artificial leg according to claim 1, further comprising an ankle structure in which the elongated body is pivotally attached 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 disposed between the connector and the ankle structure.   At least two sensors are provided, the sensors including an optical encoder and a load cell, the optical encoder being disposed about the pivot on the ankle structure, and the elongated body and the load cell being connected to the ankle structure and the load cell. 14. An instrumented prosthesis as claimed in claim 13 disposed between the connector.   The instrumented prosthetic foot according to claim 1, wherein an interface for transmitting a signal from the sensor to the connector is a wire connection.   The instrumented prosthetic foot according to claim 1, wherein an interface for transmitting a signal from the sensor to the connector is a wireless connection.   The instrumented prosthesis of claim 1, further comprising means for removably connecting an instrumented prosthesis to the prosthesis.

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