A Novel Adaptive Control Method Based on Continuous Characteristic Models

一种基于连续特征模型的新型自适应控制方法

Institute of Precision Guidance and Control, Northwestern Polytechnical University, Xi’an 710072, China

Received: 12 May 2017

Abstract

For a class of nonlinear systems, a novel adaptive control scheme is proposed in this paper. Firstly, the continuous characteristic model is constructed, which is equivalent to its original system in output for the same input at any time. Thus, the original system can be replaced with its characteristic model for designing controllers. As the original nonlinear system has unknown parameters and unmodeled dynamics, the characteristic parameters are also unknown and fast time-varying. A novel adaptive control method is proposed by combining the continuous characteristic model with the adaptive dynamic surface control technique. The method is independent on the original system model and only utilizes the information about system output for controlling. On account of the fact, the system inner states, unknown parameters and unmodeled dynamics are not needed to be observed. Finally, the stability of the closed loop system is proved by utilizing Lyapunov theory and simulation results have demonstrated the effectiveness of the proposed method.

摘要

针对一类非线性系统，提出一种新型的自适应控制方法。首先通过构造原系统的连续特征模型，使得特征模型与原非线性系统具有等效的输入-输出特性，即当输入相同时，二者的输出完全相同。所以，特征模型可以替代原系统作为被控对象进行输出反馈控制系统设计。由于原非线性系统具有未知参数和不确定性，特征模型的特征参数是未知的、快时变的。然后将连续特征模型与动态面控制技术相结合，形成一种鲁棒自适应控制方法。该方法完全不依赖原系统模型，仅利用其输出信息进行反馈控制，无需设计观测器对原系统的内部状态、未知参数和不确定性进行观测。最后采用Lyapunov理论证明了闭环系统的稳定性，仿真结果验证了方法的有效性。