Adaptive Tracking Control of State-Constrained Strict-Feedback Nonlinear Systems Using Direct Method

In this article, we focus on adaptive tracking control design for strict-feedback nonlinear systems with full state constraints. Unlike the barrier Lyapunov function method, all theoretical results are derived by direct method instead of introducing nonlinear state-dependent transformations, which reduces the calculated amount and the high sensitivity of control signals, and provides a new perspective to solve state-constrained problems. Then, by using the backstepping technique, the proposed adaptive controller maintains that the output closely tracks the desired trajectory, all signals in the closed-loop systems are bounded and the time-varying state constraints are not violated. Finally, two numerical simulations are provided to exhibit the effectiveness and superiority of the proposed adaptive tracking controller.