考虑扰动与输入饱和的机械臂连续非奇异快速终端滑模控制

针对机械臂控制过程中由于扰动与输入饱和造成的控制精度低的问题,提出一种连续非奇异快速终端滑模控制算法.首先,针对输入饱和问题,设计饱和补偿系统以消除输入饱和特性;其次,为避免滑模控制的抖振问题,设计二阶模型不确定与扰动估计器(UDE)对扰动项进行估计;同时,为进一步提高控制精度,采用自适应方法对扰动估计误差进行控制;在此基础上,设计基于二阶模型不确定与扰动估计器及输入饱和补偿的自适应连续非奇异快速终端滑模控制算法,并采用Lyapunov函数证明该算法的有限时间收敛特性;最后,以3自由度并联机械臂为控制对象进行仿真,并开展算法对比研究.仿真结果表明,该方法可以实现考虑扰动与输入饱和时的机械臂高精度有限时间轨迹跟踪控制.

Continuous non-singular fast terminal sliding mode control of robotic manipulators considering disturbance and input saturation

Aiming at the problem of low control accuracy caused by disturbance and input saturation in the process of manipulator control, a continuous non-singular fast terminal sliding mode control(CNFTSMC) algorithm is proposed in this article. Firstly, for the input saturation problem, a saturation compensation system is designed to eliminate the input saturation characteristics. Then, in order to avoid the chattering problem of sliding mode control(SMC), a second-order model uncertainty and disturbance estimator(UDE) is designed to estimate the disturbance term. At the same time, an adaptive method is used to control the disturbance estimation error to further improve the tracking accuracy. On this basis, an adaptive CNFTSMC algorithm based on the second-order UDE and input saturation compensation is designed. The Lyapunov function is used to prove the finite-time convergence characteristics of the algorithm. Finally, a 3-degree-of-freedom parallel manipulator is used as the control object to conduct simulation research, and comparison studies are carried out. The results show that the proposed method can achieve accurate finite-time trajectory tracking control considering disturbances and input saturation.