一种基于有限时间收敛微分器的NDO设计

A Nonlinear Disturbance Observer Design Based on Finite-time Convergent Differentiator

针对系统模型不确定性的问题,基于有限时间收敛微分器(Finite-time Convergent Differentiator,FD)构造了一种新型的非线性干扰观测器(Nonlinear Disturbance Observer,NDO)以实现控制系统的鲁棒性。针对现有跟踪微分器设计参数选取困难、对噪声较为敏感的问题,设计了一种构型简单、能够获得输入信号任意阶导数,并具有噪声抑制能力的有限时间收敛微分器;在此基础上,构造了一种无需任何扰动先验信息且易于工程实现的NDO。仿真结果表明,与现有跟踪微分器相比,设计的FD在输入信号导数的估计精度与噪声抑制方面具有优势,所构造的NDO对系统未知扰动可以实现更加精确、平滑的估计。

Aiming at the uncertainty of system model,a new nonlinear disturbance observer(NDO)based on finite-time convergent differentiator is proposed to realize the robustness of the control system.In allusion to the problem that the design parameters of tracking differentiator are difficult to be selected and sensitive to noise,a finite-time convergent differentiator(FD)with simple configuration,arbitrary order derivative of input signal and noise suppression ability is designed.On this basis,a NDO is constructed without any prior information of disturbance and is easy to be implemented in engineering.Simulation results show that compared with the existing tracking differentiators,the FD designed in this paper has advantages in the derivative estimation accuracy and noise suppression of input signals,and the NDO can achieve more accurate and smooth estimation of unknown disturbances of the system.