Adaptive Output Feedback Control System Design for Low-Cost Electronic Knee Prosthesis

Electronic knees provide a wide range of mobility for the amputees. These can often cover K2 and K3 grades of mobility. To achieve a wider mobility, these electronic knees depend upon feedback sensors which provide real-time data to a microcontroller. Various methods are used to calculate the joint motion and knee angle which include magnetic encoder, electro goniometer, and inertial measurement units. The goal of this paper is to develop a sensor to measure angular change of the “stump” socket using accelerometer and ultimately that of the thigh movement, and to use it as feedback signal to the microcontroller in the electronic knee. Sensing the thigh position directly can help in achieving a more natural gait. This feedback system can be used instead of the passive feedback systems currently used in the electronic knees. Results show the potential of low-cost sensing method as a reliable feedback system which can reduce complexity of the hardware as well as the algorithms currently used in the development of modern electronic knee, and hence the overall cost of the electronic knee.