Adaptive Variable Universe Fuzzy Sliding-Mode Control for Robot Manipulators With Model Uncertainty

The inaccuracy of modeling information and external disturbance bring great challenges to the control of robot manipulators. In the paper, an adaptive control strategy of robot manipulators with model uncertainty is presented by synthesizing variable universe fuzzy control (VUFC) and the sliding-mode control (SMC). The strong robustness of SMC overcomes the interference of uncertainty to the system,but brings the problem of chattering. In order to effectively alleviate chattering which is easy to occur in traditional SMC, the VUFC technology is adopted to improve the switching control and designs a dynamic variable switching control portion, which suppress the chattering significantly. Then, a suitable adaptive law is given, and the stability of the system is analyzed by utilizing Lyapunov theorem, which ensure that the system error can converge to near zero. Finally, the comparison results show that this control strategy possesses a better performance than SMC and the fuzzy SMC, which can continuously and stably achieve tracking control.