Design and Control of a Bionic Leg

Abstract

The limb amputation rate around the world is rising due to several reasons. Robotic prosthetic devices are now evolving that assist amputees in walking, picking and grasping objects, climbing stairs, and even running. However, the design and control of these robotic-powered prosthetic devices is still a big challenge. A major problem in the implementation of these devices is their safe interaction with the human amputee. This paper proposes the design and control of a robotic prosthetic knee for lower limb amputees. Design and analysis were carried out in SolidWorks and ANSYS respectively to visualize the device behavior under whole human weight. The prosthetic leg is designed for knee and ankle joints, where the knee joint is an active joint using a hydraulic actuator and the ankle joint is designed as a passive joint for flexion and extension as per the natural gait of a human. The hydraulic actuator acts as a rigid link for supporting the amputee's load; and requires no additional breaking mechanism in case of knee extension beyond the safety range. Finally, a model reference adaptive control is employed to control the torque provided to the knee joint of a prosthetic knee using MATLAB Simulink. The simulation results obtained show validation of the developed model and the controller employed for control of the knee joint.