基于自适应控制的球载吊篮姿态控制系统鲁棒性优化策略

Enhancing Robustness of Adaptive PID Controller of Stratospheric Balloon-Borne Gondola Attitude Control System

平流层球载吊篮姿态控制系统属于一类典型的非匹配不确定非线性系统,通过自适应PID控制方法的应用,在一定程度上改善了控制系统控制器的控制性能。但由于其缺乏稳定性分析及参数确定困难,限制了其进一步的应用。为此,提出一种新型多滑模控制方法对该控制器进行鲁棒性优化设计,不仅降低了不确定参数下控制器的复杂性,且使其对非线性、参数时变或摄动、不确定性以及外干扰等具有较强鲁棒性,自适应PID控制器的控制精度也得到了有效提高。

The attitude control system of a stratospheric balloon-borne gondola is a typical non-matching uncertain nonlinear system, whose performance can be enhanced to some extent by using an adaptive PID controller. But there is a lack of its stability analysis, which causes some difficulty in selecting its parameters and implementing its algorithm in case of multiple uncertain parameters. So we design a multi-sliding mode controller to help determine the parameters of the adaptive PID controller, reduce its complexity in case of multiple uncertainty parameters and enhance the robustness of nonlinearity, time-varying, vibration and outer disturbance. We use the error threshold value to ensure the robustness of the ideal approximation error of the neural network and avoid the increase of virtual and actual control of various orders, thus stabilizing the adaptive PID controller in its complex states. The computer simulation results, given in Figs.3 through 6, and their analysis show preliminarily that the adaptive PID controller we designed has a better control accuracy and robustness to nonlinearity, parameters′time-varying, uncertainty and disturbance than traditional adaptive PID controllers.