基于非线性干扰观测器的下肢外骨骼上楼梯滑模控制

针对下肢外骨骼在轨迹跟踪时对内部参数扰动和外界干扰较为敏感的特性，设计一种基于非线性干扰观测器的下肢外骨骼机器人滑模控制策略。首先建立下肢外骨骼上楼梯的动力学模型，分析其动力学特性；其次设计非线性干扰观测器，对下肢系统的不确定性和外部干扰进行观测；在此基础上，为保证系统轨迹跟踪误差的收敛性和减弱抖振，设计了低通滤波的滑模控制器，根据李雅普诺夫稳定性理论证明了下肢系统的稳定性；最后通过仿真与实验验证，该控制策略能够有效克服多种因素引起的干扰，改善系统的控制性能，提高系统的稳定性。

Sliding mode control of lower extremity exoskeleton based on nonlinear disturbance observer

Aiming at the characteristics of lower limb exoskeleton which is sensitive to internal parameter disturbance and external disturbance during trajectory tracking, this paper designed a sliding mode control strategy for lower extremity exoskeleton robot based on nonlinear disturbance observer. Firstly, it established the dynamic model of the upper extremity exoskeleton, and analyzed its dynamic characteristics. Secondly, it designed the nonlinear disturbance observer to observe the uncertainty of the lower limb system and external disturbance. On this basis, in order to ensure the convergence of the tracking error of the system trajectory and weaken the chattering, it designed a low-pass filtered sliding mode controller. According to the theory of Lyapunov stability, it proved the stability of the lower limb system. Finally, through simulation and experimental verification, the control strategy can effectively overcome the interference caused by various factors and improve the control performance and stability of the system.