Semi-actuated transfemoral prosthetic knee

A prosthetic knee device, configured to be coupled to an above-knee remaining lower limb of an amputee having a trunk, comprising:

• an artificial foot having a toe and a heel;
• a shank link coupled to the artificial foot;
• a thigh link configured to be attached to an above-knee remaining lower limb of an amputee;
• a knee mechanism interconnecting said thigh link and said shank link, said knee mechanism allowing flexion and extension movements of said thigh link and said shank link relative to each other;
• a torque generator configured to generate torque between said shank link and said thigh link;
• a knee angle sensor creating a knee angle signal representing an angle between said shank link and said thigh link;
• a stance sensor identifying which part of said artificial foot is in contact with ground;
• a power source providing electric power;
• and
• a signal processor connected to the power source, the torque generator and each of the knee angle and stance sensors, wherein said signal processor receives signals from the knee and stance sensors, determines an estimated location of the artificial foot with respect to the trunk of the amputee and, based on said estimated location when said artificial foot leaves the ground, selects a type of swing state from:
• a forward swing state;
• a combination forward and descent swing state;
• a combination forward and ascent swing state;
• a reverse swing state;
• a combination reverse and descent swing state;
• and a combination reverse and ascent swing state.