动力定位的分数阶双环自适应终端滑模控制

Fractional-order dual-loop adaptive terminal sliding mode control for dynamic positioning

针对具有非线性和环境干扰的船舶动力定位系统,本文提出了一种基于分数阶双环自适应终端滑模控制算法.首先,设计了由外环滑模控制实现自动定位于期望位置和姿态,由内环滑模控制速度和角速度.然后,证明了闭环系统的稳定性,计算了滑模的收敛时间.其次,分别对外环控制和内环控制的指数趋近项系数,进行了理论分析.分别对外环滑模和内环滑模的抖振抑制,进行了理论分析.通过自适应控制律和切换函数的设计,实现系统对动力学数学模型参数不确定性和外加干扰的鲁棒性.结果表明,所设计的控制器的动态响应要稍快于传统控制,终端滑模和分数阶滑模,且超调量小,调节时间短.最后,仿真实验验证了所设计的控制策略可行且有效.

For ship dynamic positioning system with nonlinear and environmental disturbance, a fractional-order dualloop adaptive terminal sliding mode control is proposed. Firstly, the outer-loop sliding mode control is designed to automatically locate the desired position and attitude. The inner-loop sliding mode control is used to control the velocity and angular velocity. The stability of the system is proved and the convergence time of the sliding mode is calculated. Secondly, the exponential reaching coefficients of the outer-loop control and the inner-loop control are theoretically analyzed respectively. The chattering reduction of the outer-loop sliding mode and the inner-loop sliding mode are theoretically analyzed respectively. Through the design of the adaptive control law and the switching function, the system is robust to uncertain parameters of the dynamic mathematical model and the external disturbance. The results show that the dynamic response of the designed controller is slightly faster than that of the traditional control, the terminal sliding mode and fractional order sliding mode. And its overshoot is smaller and its adjustment time is shorter. Finally, the simulation results show that the designed control strategy is feasible and effective.