一类输入饱和非仿射非线性系统的非线性动态逆控制

Nonlinear dynamic inversion approach for a class of nonaffine nonlinear systems with input saturation

中文关键词  非仿射非线性系统  非线性控制  奇异值摄动  输入饱和  反步法

英文关键词  nonaffine nonlinear systems  nonlinear control  singular perturbation  input saturation  backstepping

中文摘要

      输入饱和是实际系统中经常遇到的问题, 很多已有的控制方法要求被控系统具有仿射结构. 本文针对一类 具有输入饱和的非仿射纯反馈非线性系统提出了一种基于奇异值摄动理论的非线性动态逆控制方法. 首先构建一 个快变子系统, 在慢时间尺度下将非仿射非线性系统转换为具有仿射结构的线性系统, 从而应用已有的控制算法实 现控制目的. 为了消除输入饱和带来的影响, 建立一个中间子系统对理想控制量与输入饱和限制下控制量的差进 行估计和补偿. 所提出的控制方法不依赖于被控系统固有的时标分离特性, 并能证明闭环系统指数跟踪参考轨迹. 该方法具有良好的扩展性, 可以根据实际需求与多种控制算法相结合. 与动态面控制器和传统近似动态逆控制器的 对比仿真结果验证了本文控制方法的有效性.

英文摘要

      Input saturation is frequently encountered in practical systems, and many existing control methods require the system to be affine-in-control. In this paper, a singular perturbation theory based nonlinear dynamic inversion method is proposed for a class of nonaffine pure-feedback nonlinear systems with input saturation. Firstly, a fast dynamic subsystem is constructed to transform the nonaffine nonlinear system into a linear system in the affined form to apply the existing control algorithms in the slow time-scale. In order to eliminate the influence of input saturation, an intermediate subsystem is established to approximate and compensate the difference between the desired and saturated inputs. The provided control method is independent of the inherent time-scale character of the original system and ensures that the closed-loop system tracks the desired trajectory exponentially. The presented scheme has good expansibility, and a large number of control schemes can be combined according to the actual requirements. Simulation results are provided by comparison with dynamic surface control and traditional approximate dynamic inversion to validate the effectiveness of the proposed control method.