水下机器人基于sigmoid函数的软变结构控制

摘要

针对水下机器人滑模变结构控制系统抖振问题,利用具有光滑性和饱和性的sigmoid函数,提出一种水下机器人软变结构控制策略.利用Lyapunov稳定性理论,讨论控制受限情形的水下机器人软变结构控制系统的稳定性,构造基于sigmoid函数的软变结构控制器,给出水下机器人软变结构控制的具体算法.将基于sigmoid函数的软变结构控制策略用于水下机器人仿真实验研究,实验结果验证了该方法的可行性和有效性.与线性控制、饱和线性控制和基于变饱和函数的软变结构控制3种控制方法进行对比仿真分析,分析结果表明,基于sigmoid函数设计的软变结构控制系统调节精确度高、响应速度快,有效地削弱了系统抖振,具有良好的动态性能.%Aiming at the chattering problem to sliding mode variable structure control systems for autonomous underwater vehicles ( AUVs) , a control strategy named as soft variable structure control ( SVSC ) based on sigmoid functions with smoothness and saturability is presented. The stability of SVSC systems with restricted controls for AUVs was analyzed by Lyapunov stability theory. The soft variable structure controller based on sigmoid functions was designed and the concrete algorithm on the SVSC for AUVs was given. The SVSC strategy based on sigmoid functions was applied to AUV simulation experments, and the experiment results were carried out to verify the feasibility and effectiveness of the proposed strategy. Compared with linear control, saturated linear control and SVSC based on variable saturations, high regulation rates were achieved, and response speed is fast by SVSC based on sigmoid functions for AUVs. The SVSC systems for AUVs can decrease system chattering and enhance the dynamic performance of the control systems.