Adaptive model-free control of lower limb exoskeletons using neural estimation and swarm-based optimization
摘要
The design of robust control systems for rehabilitation exoskeletons is essential to improve patient mobility and recovery. This paper proposes a novel model-free adaptive backstepping control strategy, specifically developed for a 10-degree-of-freedom (DOF) lower limb exoskeleton intended for rehabilitation. The originality of this work lies in the synergistic combination of several advanced techniques: a second-order ultra-local model is used to bypass the complexities of system dynamics, a multilayer perceptron (MLP) neural network is integrated to estimate and compensate for lumped disturbances in real time, and particle swarm optimization (PSO) is applied to automatically tune the controller parameters for optimal performance. This integrated approach enables adaptive, precise, and stable control without relying on a predefined model. The closed-loop system stability is formally proven using Lyapunov theory. Validation is carried out through co-simulation with SolidWorks, Simscape Multibody, and MATLAB/Robotics Toolbox, and the results demonstrate clear improvements in control accuracy and robustness compared to existing model-free methods.