Structural Design of Knee-Joint Locking Mechanism and Adaptive Fuzzy Control for Lower Limb Exoskeletons

This paper redesigns a knee-joint locking structure and presents its adaptive fuzzy control method in the lower limb exoskeleton system, which is devoted to assisting paraplegic patients in rehabilitation training. Firstly, the knee-joint locking structure is developed based on experimental knee joint position error data by incorporating kinematic and force analyses. To ensure the stability of the exoskeleton system with knee locking mechanism, and then an adaptive fuzzy controller is designed, in which the uncertainties and nonlinearities are compensated by using fuzzy logic systems. Finally, the effectiveness of the proposed mechanism and control strategy is validated through simulations, that is, the proposed locking structure and control strategy contribute to reducing muscle burden and enhancing rehabilitation efficiency.