A high performance, low-cost passive prosthetic knee includes one or more modules to enable able-bodied gait by transfemoral amputees to improve metabolic efficiency and reduce stigma from conspicuous abnormal gaits. A stance stability module includes a latch with a virtual lock axis that automatically locks and unlocks. An early stance flexion module enables able-bodied gait during stance. Hydraulic fluid dampers ensure reliable swing phase control. A swing extension energy storage module stores and returns energy as the knee locks and unlocks, respectively. These modules may be used together, in any combination, or individually.

A lower limb prosthesis comprises a knee chassis (10), a shin carrier (20) pivotally connected to the knee chassis (10) and a piston and cylinder assembly (30, 40) pivotally connected to the knee chassis (10) and the shin carrier (20). The piston and cylinder assembly (30, 40) comprises a piston assembly (40) comprising a piston (40) mounted on a piston rod (42), a cylinder body (32B) having a cavity (46) defining a cylinder within which the piston (44) is arranged to reciprocate along the piston and cylinder assembly axis, and a foot component attachment means (36) for attaching a foot component to the piston and cylinder assembly (30, 40).

A prosthetic device has a movable body and foot member with an end effector for contacting an external surface. A base body is coupled to a first joint of the foot member. A compliant linking member is disposed between a second joint of the foot member and a first joint of the moveable body. The compliant linking member can be a spring or flexible beam. A passive linking member is coupled between a third joint of the foot member and a third joint of the moveable body. An actuator is disposed between the base body and the second joint of the movable body. The actuator can be a motor with an extension member. The compliant linking member extends during roll-over phase. The actuator acts to assist with the extension of the compliant linking member during roll-over phase to aid with push-off phase in the gait cycle.

Systems, methods, and apparatus provide an artificial knee. Such artificial knees may include a thigh link configured to move in unison with a thigh of the person, a shank link configured to be rotatably coupled to the thigh link, and a compression spring rotatably coupled to the thigh link at a first end and coupled to the shank link at a second end. The compression spring is configured to provide an extension torque between the thigh link and the shank link during a first range of motion of the thigh link and the shank link relative to each other. The compression spring is configured to provide a flexion torque between the thigh link and the shank link during a second range of motion of the thigh link and the shank link relative to each other.

The present disclosure provides for a device and method of control for an artificial prosthetic knee. A prosthetic knee according to the present disclosure relies on strictly passive means of providing support during weight bearing and supplements a resistive swing-phase mechanism with a small powered actuator. This actuator adds power to the knee, exclusively during swing phase, to improve swing-phase behavior. In particular, the knee still relies on the resistive swing-phase mechanism to provide nominal swing-phase knee motion, but supplements that motion as needed with the small powered actuator.

A prosthetic system includes a prosthetic knee having a controller and a hydraulic unit pivotally connected to the controller. The hydraulic includes a reserve hydraulic cylinder, a brake hydraulic cylinder, and a hydraulic cylinder having a lower hydraulic compartment. A flow system fluidly connects the hydraulic cylinder, the reserve hydraulic cylinder, and the brake cylinder. The flow system has first and second flow paths in communication with the lower hydraulic compartment and the reserve hydraulic cylinder. The first flow path is in communication with lower hydraulic compartment and the reserve hydraulic cylinder via the brake cylinder. The second flow path bypasses the brake hydraulic cylinder.

A multi-articulated link knee joint includes: a knee unit in which an upper link unit rotates relative to a lower link unit by a multi-articulated link mechanism including a plurality of link units including the upper link unit and the lower link unit; a relative position detector for detecting a relative position of the upper link unit relative to the lower link unit; and an angle detector for obtaining a bending angle of the knee unit from the detected relative position.

A multi-articulated link knee joint includes: a knee unit in which an upper link unit rotates relative to a lower link unit by a multi-articulated link mechanism including a plurality of link units including the upper link unit and the lower link unit; a cylinder device for assisting the motion of the knee unit and moving in accordance with the rotation of the upper link unit; a position detector for detecting the distance from the lower link unit to the cylinder device; and an angle detector for obtaining the bending angle of the knee unit from the detected distance from the cylinder device.

A polycentric knee joint including an adjustment-free multi-stage prosthesis air cylinder. The air cylinder has an air cylinder body, a piston assembly slidably mounted on the air cylinder body, a first check valve mounted in the piston, and a multi-stage air pressure valve mounted inside a lower air way of the air cylinder body. The multi-stage air pressure valve automatically cushions movements of the piston assembly without being adjusted whenever a user of the prosthesis joint walks slowly or quickly, for improved comfort.

A multi-articulated link knee joint includes: a knee unit in which an upper link member is structured to rotate relative to a lower link member by a multi-articulated link mechanism including a plurality of link members including the upper link member and the lower link member; a driven member to move in accordance with the rotation of the upper link member; a position detector for detecting the position of the driven member, the position detector provided at the lower link member; and an angle detector for obtaining the bending angle of the knee unit from the position of the driven member.