下肢外骨骼系统摆动相非线性干扰观测器设计

Design of nonlinear disturbance observer for lower extremity exoskeleton system of swing phase

针对下肢外骨骼在运行过程中,穿戴者提供的主动力矩不确定问题,本文进行了基于干扰观测技术的摆动相控制方法研究。利用拉格朗日原理对简化后的实物模型进行动力学分析,建立下肢外骨骼摆动相模型。考虑模型的非线性、强耦合特征设计滑模控制器,基于干扰观测器对穿戴者的主动力矩进行估计,实现对滑模控制器的补偿,并对观测器/控制器综合设计的闭环系统稳定性进行证明。搭建下肢外骨骼控制系统仿真平台进行髋关节和膝关节的角度控制。实验结果证明,所设计的闭环系统对期望角度具有良好的跟随能力,可以有效抑制干扰的影响。

Considering the uncertainty of the active moments by the wearer′s muscles during the lower extremity exoskeleton operation,this study investigates the swing phase control method based on the disturbance observer technology.The physical model was simplified.Lagrange principle was used to analyze the dynamic characteristics,and a swing model of the lower limb exoskeleton was established.The sliding mode controller was designed,considering the nonlinearity and strong coupling characteristics of the model.The active torque of the wearer was estimated based on disturbance observer technology to compensate the sliding mode controller,and the closed-loop system for the observer/controller integrated design was found to be stable.The control system simulation platform was established to control the angle of hip and knee joints.The results demonstrate that this closed-loop system can effectively follow the desired angle and restrain disturbances.