Powered knee and ankle prosthesis controller for adaptive ambulation
Disclosed are embodiments of a volitional controller and prosthetic leg system comprising a volitional controller and a powered prosthetic leg. The volitional controller may be configured to control a powered knee joint and a powered ankle joint to enable a user to walk at different speeds and inclines. The orientation of the components of the powered prosthetic leg may be monitored continuously to enable the system to adapt to changes in the duration of the user's gait. The volitional controller may be configured to determine a target knee torque and a target ankle torque that may be based on the global shank orientation, a prosthetic knee velocity, and a prosthetic ankle velocity.
1 . A powered leg prosthesis system, comprising:
a powered leg prosthesis comprising a shank that includes a proximal end and a distal end, a powered knee joint connected to the proximal end of the shank, a powered ankle joint connected to the distal end of the shank, and a prosthetic foot connected to the powered ankle joint; and
a volitional controller, the volitional controller comprising one or more processors and one or more hardware storage devices having instructions stored thereon that are executable by the one or more processors to cause the controller to at least:
determine a global shank orientation, wherein the global shank orientation is the angle between the shank of the powered lower leg prosthesis and direction of gravity;
determine a target ankle torque based on the global shank orientation;
determine a biarticular torque based on the target ankle torque;
determine a target knee torque based on the biarticular torque; and
output a knee torque signal for controlling the powered knee joint of the powered leg prosthesis based on the determined target knee torque,
wherein the biarticular torque is proportional to and opposite the target ankle torque.
2 . The powered leg prosthesis system of claim 1 , wherein the instructions further cause the controller to output an ankle torque signal for controlling the powered ankle joint of the powered leg prosthesis based on the determined target ankle torque.
3 . The powered leg prosthesis system of claim 1 , wherein determining the target knee torque is further based on a first virtual damping torque, wherein the first virtual damping torque is proportional to and opposite a prosthesis knee velocity.
4 . The powered leg prosthesis system of claim 1 , wherein the biarticular torque increases with ankle plantarflexion torque.
5 . The powered leg prosthesis system of claim 1 , wherein determining the target ankle torque is further based on a shank torque, wherein the shank torque is proportional to and opposite the global shank orientation.
6 . The powered leg prosthesis system of claim 1 , wherein determining the target ankle torque is further based on a second virtual damping torque, wherein the second virtual damping torque is proportional to and opposite a prosthetic ankle velocity.
7 . The powered leg prosthesis system of claim 1 , wherein the volitional controller is configured to adapt to an incline and/or uneven terrain based solely on the global shank orientation.
8 . The powered leg prosthesis system of claim 1 , wherein the target knee torque is output by the volitional controller when the volitional controller determines that the powered leg prosthesis is in a stance state.
9 . The powered leg prosthesis system of claim 8 , wherein the instructions, when the volitional controller determines that the powered leg prosthesis is in a swing state, cause the volitional controller to:
determine an ankle transition orientation; and
determine a target swing torque based on the ankle transition orientation.
10 . The powered leg prosthesis system of claim 8 , wherein when the volitional controller determines that the powered leg prosthesis is in a swing state, a desired end position of the knee and/or ankle joints is determined using a minimum-jerk optimizer.
11 . The powered leg prosthesis system of claim 1 , wherein the powered leg prosthesis comprises a ground reaction force sensor and/or one or more IMU sensors.
12 . A powered leg prosthesis system, comprising:
a powered leg prosthesis comprising a shank that includes a proximal end and a distal end, a powered knee joint connected to the proximal end of the shank, a powered ankle joint connected to the distal end of the shank, and a prosthetic foot connected to the powered ankle joint; and
a volitional controller, the volitional controller comprising one or more processors and one or more hardware storage devices having instructions stored thereon that are executable by the one or more processors to cause the controller to at least:
determine a global shank orientation, wherein the global shank orientation is the angle between the shank of the powered lower leg prosthesis and direction of gravity;
determine a target ankle torque based on the global shank orientation;
determine a biarticular torque based on the target ankle torque;
determine a target knee torque based on the biarticular torque; and
output a knee torque signal for controlling the powered knee joint of the powered leg prosthesis based on the determined target knee torque,
wherein the biarticular torque increases with ankle plantarflexion torque.
13 . A powered leg prosthesis system, comprising:
a powered leg prosthesis comprising a shank that includes a proximal end and a distal end, a powered knee joint connected to the proximal end of the shank, a powered ankle joint connected to the distal end of the shank, and a prosthetic foot connected to the powered ankle joint; and
a volitional controller, the volitional controller comprising one or more processors and one or more hardware storage devices having instructions stored thereon that are executable by the one or more processors to cause the controller to at least:
determine a global shank orientation, wherein the global shank orientation is the angle between the shank of the powered lower leg prosthesis and direction of gravity;
determine a target ankle torque based on the global shank orientation;
determine a biarticular torque based on the target ankle torque;
determine a target knee torque based on the biarticular torque; and
output a knee torque signal for controlling the powered knee joint of the powered leg prosthesis based on the determined target knee torque,
wherein determining the target ankle torque is further based on a shank torque, wherein the shank torque is proportional to and opposite the global shank orientation.
14 . A powered leg prosthesis system, comprising:
a powered leg prosthesis comprising a shank that includes a proximal end and a distal end, a powered knee joint connected to the proximal end of the shank, a powered ankle joint connected to the distal end of the shank, and a prosthetic foot connected to the powered ankle joint; and
a volitional controller, the volitional controller comprising one or more processors and one or more hardware storage devices having instructions stored thereon that are executable by the one or more processors to cause the controller to at least:
determine a global shank orientation, wherein the global shank orientation is the angle between the shank of the powered lower leg prosthesis and direction of gravity;
determine a target ankle torque based on the global shank orientation;
determine a biarticular torque based on the target ankle torque;
determine a target knee torque based on the biarticular torque; and
output a knee torque signal for controlling the powered knee joint of the powered leg prosthesis based on the determined target knee torque,
wherein determining the target ankle torque is further based on a second virtual damping torque, wherein the second virtual damping torque is proportional to and opposite a prosthetic ankle velocity.
15 . A powered leg prosthesis system, comprising:
a powered leg prosthesis comprising a shank that includes a proximal end and a distal end, a powered knee joint connected to the proximal end of the shank, a powered ankle joint connected to the distal end of the shank, and a prosthetic foot connected to the powered ankle joint; and
a volitional controller, the volitional controller comprising one or more processors and one or more hardware storage devices having instructions stored thereon that are executable by the one or more processors to cause the controller to at least:
determine a global shank orientation, wherein the global shank orientation is the angle between the shank of the powered lower leg prosthesis and direction of gravity;
determine a target ankle torque based on the global shank orientation;
determine a biarticular torque based on the target ankle torque;
determine a target knee torque based on the biarticular torque; and
output a knee torque signal for controlling the powered knee joint of the powered leg prosthesis based on the determined target knee torque,
wherein determining the target knee torque is further based on a first virtual damping torque, wherein the first virtual damping torque is proportional to and opposite a prosthesis knee velocity.