L₁ Adaptive Control for a Class of Uncertain Nonaffine-in-Control Nonlinear Systems

This technical note presents an L₁ adaptive controller for a class of nonlinear uncertain systems, nonaffine in control. As compared to previous L₁ architectures for nonlinear nonaffine-in-control systems, the solution discussed in this technical note admits a broader class of nonlinear systems by relaxing some of the (restrictive) assumptions previously made. We also consider a more general filtering structure and prove the results using partial knowledge of the control input actuator model. With the presented control architecture we are able to improve the performance and robustness of the closed-loop adaptive system, compared to prior results of L₁ adaptive control for nonaffine-in-control systems.