Periodic Steady State Analysis of Lower Limb Rehabilitation Robot Based on Max-plus Algebra

The periodic steady state and the autonomous control of a lower limbs rehabilitation robotic walking training system are studied in this paper. Using the timing event diagrams and the max - plus algebra method, a mathematical model of the lower limb rehabilitation robotic walking training system is built. The system cycle calculation formula, estimation of the range of periodic steady state disturbance and independent control strategy are provided, as well as the robustness analysis of cycle stationary relative to parameter perturbations. The periodic steady state disturbance estimation can be used to improve the accuracy and compliance of lower limb rehabilitation robot. The autonomous control strategy is beneficial to ensure the real-time performance and safety of lower limb rehabilitation robot. The proposed disturbance estimation and autonomous control methods are easy to implement on a lower limb rehabilitation robot.