气动人工肌肉关节的自抗扰控制

Active Disturbance Rejection Control for the Joint Driven by PMAs

  • 摘要: 气动人工肌肉关节系统是一个强非线性时变自平衡2阶系统,鉴于传统控制方法难以克服控制精度、调节速度和稳定性之间的矛盾,设计了一种2阶自抗扰控制器.采用3阶扩张状态观测器实时估计未建模型部分及外界扰动,对系统进行线性补偿,并利用非线性反馈机制提高控制效率,在保证稳定性的前提下,提高调节速度和控制精度,使得系统的稳态精度小于0.1°,跟踪精度小于0.5°.试验证明,即使在系统模型部分已知或未知的情况下,系统采用自抗扰控制仍然可以使控制效果达到令人满意的程度.

     

    Abstract: The system of a joint driven by PMAs(pneumatic muscle actuators) is a strong nonlinear time-varying self-balanced second-order system.Traditional control methods are difficult to overcome the conflict between the control accuracy, the regulating speed and the stability.A second-order active disturbance rejection control(ADRC) is designed,in which a third-order ESO(extended states observer) is adopted to estimate the non-modeling part and external disturbance in real time and to make the linear compensation for system.Meanwhile,the control efficiency is improved by a nonlinear feedback. On the premise of ensuring the stability,the adjusting speed and control accuracy is enhanced.The system's steady-state accuracy is less than 0.1°and the tracking accuracy is less than 0.5°.Even in the case of the unknown or partly known system model,the system using ADRC can still achieve a satisfactory control result.

     

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