Powered-on passive knee prosthesis system

A knee prosthesis system comprising:

• a knee prosthesis including a thigh segment and a shank segment;
• at least one actuator rotatably connecting the shank segment and the thigh segment, the at least one actuator being configured to controllably assume a powered knee behavior to generate knee motion or a passive knee behavior to resist knee motion;
• and
• a controlling unit including a finite-state control structure, the controlling unit electrically communicating with the at least one actuator, the control structure comprising at least three passive states and at least one powered state, the at least three passive states including a passive stance-resistance state, a passive swing-flexion state, and a passive swing-extension state, the at least one powered state including at least one of a powered swing-assistance state, a powered stance-assistance state, and a powered-swing state,
• wherein the at least one powered state is the powered stance-assistance state, the controlling unit selecting the powered stance-assistance state from the passive stance-resistance state based on detection of an entry condition, and the controlling unit exiting the powered stance-assistance state into the passive stance-resistance state upon detection of an exit condition,
• wherein the entry condition selecting the powered stance-assistance state from the passive stance-resistance state includes at least detection of a knee joint extension, the exit condition exiting the powered stance-assistance state into the passive stance-resistance state includes at least detection of knee joint flexion.

A knee prosthesis system comprising:

• a knee prosthesis including a thigh segment and a shank segment;
• at least one actuator rotatably connecting the shank segment and the thigh segment, the at least one actuator being configured to controllably assume a powered knee behavior to generate knee motion or a passive knee behavior to resist knee motion;
• and
• a controlling unit including a finite-state control structure, the controlling unit electrically communicating with the at least one actuator, the control structure comprising at least three passive states and at least one powered state, the at least three passive states including a passive stance-resistance state, a passive swing-flexion state, and a passive swing-extension state, the at least one powered state including at least one of a powered swing-assistance state, a powered stance-assistance state, and a powered-swing state,
• wherein the at least one powered state is the powered stance-assistance state, the controlling unit selecting the powered stance-assistance state from the passive stance-resistance state based on detection of an entry condition, and the controlling unit exiting the powered stance-assistance state into the passive stance-resistance state upon detection of an exit condition,
• wherein the powered stance-assistance state provides an assistive knee extension torque that is a function of at least a measured force in the knee prosthesis and a measured angular velocity of the thigh segment.

A knee prosthesis system comprising:

• a knee prosthesis including a thigh segment and a shank segment;
• at least one actuator rotatably connecting the shank segment and the thigh segment, the at least one actuator being configured to controllably assume a powered knee behavior to generate knee motion or a passive knee behavior to resist knee motion;
• and
• a controlling unit including a finite-state control structure, the controlling unit electrically communicating with the at least one actuator, the control structure comprising at least three passive states and at least one powered state, the at least three passive states including a passive stance-resistance state, a passive swing-flexion state, and a passive swing-extension state, the at least one powered state including at least one of a powered swing-assistance state, a powered stance-assistance state, and a powered-swing state,
• wherein the at least one powered state is a powered-swing state, the controller selecting the powered-swing state from the passive swing-flexion state based on detection of an entry condition, and the controller exiting the powered-swing state into the passive stance-resistance state upon detection of an exit condition,
• wherein the entry condition selecting the powered-swing state from the passive swing-flexion state includes at least detection of a full knee joint extension when the knee prosthesis is unloaded, or axial acceleration of the shank segment above a threshold value when the knee prosthesis is unloaded, and wherein the exit condition includes at least detection of prosthesis loading.

A lower limb prosthesis comprising:

• a foot prosthesis;
• and
• a knee prosthesis system including a thigh segment, a shank segment, at least one actuator and a controlling unit, the at least one actuator rotatably connecting the shank segment and the thigh segment, the at least one actuator being configured to controllably assume a powered knee behavior to generate knee motion or a passive knee behavior to resist knee motion, the controlling unit including a finite-state control structure, the controlling unit electrically communicating with the at least one actuator, the control structure comprising at least three passive states and at least one powered state, the at least three passive states including a passive stance-resistance state, a passive swing-flexion state, and a passive swing-extension state, the at least one powered state including at least one of a powered swing-assistance state, a powered stance-assistance state, and a powered-swing state,
• wherein the passive stance-resistance state provides a high resistance against knee flexion, the passive swing-flexion state providing relative low resistance against knee flexion, the passive swing-extension state providing a low resistance against knee extension that increases substantially as a knee nears full extension, and wherein the powered swing-assistance state provides an assistive torque that flexes a knee joint, the powered stance-assistance state providing an assistive torque that extends the knee joint, and the powered-swing state providing a prescribed knee joint motion.