Tracking Control of Strict-Feedback System Based on Fully Actuated System Approach

For the tracking control problem of a class of strict-feedback nonlinear systems with output constraints and unknown external disturbances, the adaptive control method based on fully actuated system (FAS) approach is proposed. Through model transformation, the original system is equivalently transformed into the high-order fully actuated system (HOFAS), which makes the solution of the control law simple and effective. Then, the tangent barrier Lyapunov function (tBLF) is constructed to ensure no constraint violation. For the unknown external disturbance of the system, the disturbance observer (DO) is used to estimate and compensate in time. The stability analysis shows that all signals of the closed-loop system are eventually bounded. Finally, the superiority and effectiveness of the proposed method are verified by simulation examples.