Development of Powered Semi-Active Ankle-Foot Prosthetic with Fuzzy Logic-PI Controller

Abstract

One of the most difficult issues in the design of power ankle-foot prosthetics is to create a control system that can simulate biological ankle-foot behavior in various operating conditions. The mechanical design of a novel PSAAP is studied. The powered semi-active anklefoot prosthetic is a complex nonlinear system with high coupling. For powered ankle prostheses, a fuzzy logic-proportional-integral (FLC-PI) controller is presented. In the initial stage of control, two proportional-integral (PI) controllers are designed to regulate motor speed and current, respectively. In the next stage of control, two FLC-PI controllers are designed. The PI controller's gains are intended to be adjusted online by the fuzzy logic controller. FLC-PI controllers are used to control the designated model under these external disturbances during a typical walking gait cycle. The performance of PI controllers and FLC-PI controllers are compared during the walking gait cycle. The results reveal that a powered semi-active ankle-foot prosthetic with a fuzzy logic-PI controller method outperforms a PI controller alone.