Adaptive variable universe fuzzy control for a class of pure-feedback systems with unknown dead-zone

In this paper, based on variable universe fuzzy tracking control (VUFC), we present a novel adaptive algorithm for a class of pure-feedback systems with unknown dead-zone inputs. With some new states variables and coordinate transforms, the system is converted into the normal system and observers need to be designed. So, we can consider VUFC scheme rather than backstepping scheme. VUFC are mainly based on the changing of contraction and expansion factor to change the universe of the variables to develop the control performance. According to Lyapunov stable theorem analysis, the stability of all the signals in the closed-loop system can be guaranteed and the tracking error is proven to converge to a small neighborhood of the origin. This new algorithm can improve the accuracy of the system, alleviate tracking error, strong robustness. Simulation results are presented to verify the effectiveness of the proposed approach.