School of Mechanical and Power Engineering, Nanjing Tech University, Nanjing 211816, China.
School of Mechanical Engineering, Nanjing University of Science and Technology, Nanjing 210094, China.
ISA Trans. 2022 Mar;122:49-62. doi: 10.1016/j.isatra.2021.04.017. Epub 2021 Apr 22.
Extended state observer acting as a popular tool can estimate the system states and total disturbances simultaneously. However, for extended-state-observer-based control of high-order nonlinear systems, there are still some difficult issues to solve, such as how to simultaneously reject matched and mismatched model uncertainties with strict theoretical proof, especially in the case of output feedback, "explosion of complexity" and so on. Motivated by these reasons, different control schemes in full-state feedback and output feedback conditions respectively will be integrated via the filter-based backstepping approach for saturated nonlinear systems. For the full-state feedback condition, adaptive neural network and extended state observer will be combined for each dynamic to handle the unknown nonlinear dynamics and external disturbances, respectively. For the output feedback condition, nonlinear disturbance observer design will be incorporated into the neural-network-based extended state observer scheme to handle mismatched disturbances at the same time. In particular, an auxiliary system will be constructed to compensate for the saturation influence. Moreover, the anticipate control effects of the developed controllers have been demonstrated by contrastive results for a hydraulic servo system.
扩张状态观测器作为一种流行的工具，可以同时估计系统状态和总干扰。然而，对于高阶非线性系统的扩张状态观测器控制，仍然存在一些难以解决的问题，例如如何在严格的理论证明下同时拒绝匹配和不匹配的模型不确定性，特别是在输出反馈的情况下，还存在“复杂性爆炸”等问题。基于这些原因，将分别在全状态反馈和输出反馈条件下的不同控制方案通过基于滤波器的反推方法集成到饱和非线性系统中。对于全状态反馈条件，自适应神经网络和扩张状态观测器将分别结合到每个动态中，以处理未知的非线性动态和外部干扰。对于输出反馈条件，将非线性干扰观测器设计纳入基于神经网络的扩张状态观测器方案中，以同时处理不匹配的干扰。特别地，构建一个辅助系统来补偿饱和的影响。此外，通过对液压伺服系统的对比结果，验证了所开发控制器的预期控制效果。
