Quasi-Static Modelling of a Redundant Knee Prosthesis

Developing mechanical devices to restore natural locomotion for transfemoral amputees still raises many challenges. One of them is the development of an efficient control strategy for the prosthesis active joints, with the objective of making it flexible and intuitive to use. This paper reports the modelling of the knee joint of the transfemoral CYBERLEGs Beta-Prosthesis, an actuated elastic ankle-knee prosthesis designed with the objective to minimize its total power consumption. More precisely, we report the static model of the prosthetic knee that was used to build its low-level controller, converting the desired torque into a reference position for the joint actuator. Bench testing of the prosthetic knee was performed to show that this static model is able to accurately predict the actual behaviour of the device.