Adaptive non‐backstepping fuzzy tracking control for a class of multiple‐input–multiple‐output pure‐feedback systems with unknown dead‐zones

In this study, the authors present a novel adaptive non‐back‐stepping alleviating computation tracking control algorithm for a class of MIMO pure‐feedback systems with unknown dead‐zone inputs. Based on the introduced new state variables and coordinate transforms, the pure‐feedback form is converted into a normal form where back‐stepping scheme is not necessary. Owing to the unavailability of the new states, the tracking control problem is changed from a state‐feedback one to an output‐feedback one. Therefore, observers need to be designed to estimate the indirect un‐measurable states. In the controller and observer design procedure, the control method is based on non‐back‐stepping scheme and for each subsystem only three adaptive adjusted parameters are needed to be updated on‐line. Thus, different from the back‐stepping‐based ones, this new algorithm can not only alleviate on‐line computation burden but also can considerably simplify the control procedure. According to Lyapunov stable analysis methods, the bounded of all the signals in the closed‐loop system can be guaranteed and the tracking error is proven to converge to a small neighbourhood of the origin. Simulation results are presented to illustrate the effectiveness of this proposed approach.