船舶航向非线性输出反馈控制

Nonlinear output feedback control for ships' course

为解决船舶航向控制系统的模型不确定性、高度非线性以及状态变量与控制输入的约束问题,提出一种基于滑模控制的反馈控制算法.利用递归迭代设计法,将非线性滑动模态建立到扩展状态空间,并结合增量反馈控制,无须对不确定项进行估计.在系统输入增益符号已知条件下可自动寻找使系统稳定的控制量,避免变结构控制的抖振以及输出反馈控制的稳态误差及超调,并保证闭环系统的高阶状态变量严格有界.应用船舶非线性水动力模型进行航向控制仿真.结果表明,控制器对系统参数摄动及外界干扰不敏感,具有强鲁棒性.

A novel feedback control algorithm was developed based on sliding mode control for ships＇ course control system to solve the problems of uncertainty, high nonlinearity, states constraints and actuator saturation. In a recursive and iterative procedure, the nonlinear sliding mode was designed on phase planes in the augmented states space, and increment feedback law was developed. The proposed controller could automatically seek control input quantity that guaranteed the closed-loop system stable without uncertainty estimation. The problems of chattering in variable structure control and overshoot or static error resulted from conventional output feedback were also circumvented. And the high order states in closed-loop system were controlled strictly bounded. Computer simulation results on a full nonlinear hydrodynamic ship model verify that the proposed controller is robust to the variations or disturbances.