Adaptive robust control of a class of nonlinear systems with time-varying parameters and bounded control coefficient
一类控制系数有界的时变非线性系统的自适应鲁棒控制

This paper designs an adaptive robust controller for a class of strict-feedback nonlinear systems with timevarying parameters and bounded control coefficient and disturbances. Incorporating Nussbaum function gain and smooth projection algorithm with adaptive backstepping design tools, this design method does not require a priori knowledge of the sign of the time-varying control coefficient and the bound of time-varying parameters and disturbances. By means of Lyapunov function and related lemmas, we prove that the designed adaptive robust nonlinear controller guarantees the global uniform boundedness of all signals of the resulting closed-loop system. The desired system performances can be achieved by appropriately selecting the design parameters. Simulation studies show the feasibility and effectiveness of the presented approach.