一种改进的AUVs变结构滑模控制策略研究

针对现有的变结构滑模控制切换面单一性会导致系统状态在原点处收敛缓慢的缺陷,对自主式水下机器人(AUVs)变结构滑模控制设计了折线型的切换面,并且进一步改进实现了速度控制和定点定速控制。改进的切换面由斜率不同的自线段构成,并在拐点处通过S型函数光滑过渡。将切换面的斜率减小到0时,则可以实现速度控制,同时为了消除速度控制的稳态误差,引进了采用能智积分方法的积分项。最后在某AUV上进行仿真实验,结果证实了应用折线型切换面可以减少控制系统的上升时间,提高反应速度；速度控制的稳态误差接近0,并很好地实现定点定速的控制效果。该方法可以有效用于AUVs的控制。

An Improved Sliding Mode Controller for AUVs

As sliding mode (SMC) control has just a unitary switching face, the system converges slowly at the origin, an improvement is made to the linear switching surface of SMC for autonomous underwater vehicles (AUVs). A polyline switching surface is proposed, velocity control and velocity control at appointed positions were realized. The improved switching surface was made up of the lines with different slopes, and it is smoothed at break with sigmoid functions. The slope of switching surface is set 0 to realize velocity control and the intelligent integral is introduced to reduce the steady-state error of velocity control. Finally, the simulation experiments have been carried on AUV. The results show that polyline switching surface can reduce the rise time of system and accelerate system response, the steady-state error approaches 0 at velocity control and the velocity control are realized perfectly. This method can be effectively used for the control of AUVs.