Adaptive Actuator Failure Compensation Control of Second-Order Nonlinear Systems With Unknown Time Delay

In this paper, a robust adaptive control law is proposed based on backstepping technique for strict-feedback systems with unknown actuator failure and unknown time delay. Unlike existing results, the bounding function of the time delay term is allowed to depend on all system states, and thus the triangular structure of the system to be controlled is destroyed. By constructing a linear projection between the state vector (x₁, x₂) and its transform (z₁, z₂) in controller design, the triangular structure requirement of backstepping technique is no longer needed. Simulation results show that the designed controller can ensure the stability of the closed-loop system.