This study uses an output feedback disturbance observer-based proportional derivative (PD) controller with variable damping ratios for a class of single-input, single-output nonlinear systems in the presence of unknown disturbances. The proposed sliding mode state and disturbance observer, in which the switching term of the output estimation error is employed to counteract the effect of external disturbance, ensures that the estimation error is finally bounded in a neighborhood and reconstructs simultaneously the system state and unknown disturbance. Herein, the characteristics of the proposed observer are presented in the frequency domain, followed by the corresponding analysis in the time domain. A nonlinear PD controller with a variable damping ratio designed using the estimation state and disturbances should achieve low overshoot and short settling time. Finally, the simulation results demonstrate the validity of the proposed method.

中文翻译：

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基于滑模状态和干扰观测器的非线性系统控制器设计

本研究使用基于输出反馈干扰观测器的比例微分 (PD) 控制器，该控制器具有可变阻尼比，用于存在未知干扰的一类单输入、单输出非线性系统。所提出的滑模状态和扰动观测器，其中使用输出估计误差的切换项来抵消外部扰动的影响，确保估计误差最终在一个邻域内，并同时重构系统状态和未知扰动。在这里，提出的观测器的特性在频域中呈现，然后在时域中进行相应的分析。使用估计状态和扰动设计的具有可变阻尼比的非线性 PD 控制器应实现低超调和短稳定时间。最后，仿真结果证明了所提出方法的有效性。