基于功能性电刺激的腕部震颤抑制系统线性自抗扰控制

Linear active disturbance rejection control of wrist tremor suppression system based on functional electrical stimulation

功能性电刺激是实现病理性腕部震颤抑制的重要手段.但是,由于腕部肌骨系统生理特性复杂,难以对其准确建模,限制了震颤抑制控制的效果.针对上述问题,首先,建立腕部肌骨系统的Hammerstein模型,给出参数辨识方法;然后,针对肌肉非线性招募特性通过前馈控制进行模型线性化,进而设计自抗扰控制器实现对肌骨系统建模误差和震颤等外部扰动的估计和补偿,根据带宽法和稳定裕度要求完成控制器参数整定,并对闭环系统的跟踪和抗扰性能进行仿真分析;最后,基于腕部震颤抑制系统平台对所提出自抗扰控制方法与PID控制进行对比实验,验证所提出控制方案的有效性.

Functional electrical stimulation is one of effective and important means of pathological tremor suppression.However,due to the complex physiological and structural characteristics of the wrist musculoskeletal system,it is difficult to develop its accurate model,which greatly limits the performance of tremor suppression.In this paper,we first establish a Hammerstein model of wrist musculoskeletal system and propose a parameter identification procedure.Then,a feed-forward linearization controller is designed to cancel the nonlinear muscle recruitment characteristics.An active disturbance rejection control is proposed to estimate and compensate the model errors and external disturbances.The bandwidth method and stability margin analysis are used to complete the parameter tuning of the active disturbance rejection controller,and the tracking performance and disturbance rejection property are verified by simulation.Finally,based on the tremor suppression platform,comparative experiments with the PID controller are carried out to verify the effectiveness of the proposed control method.