Abstract:

Combined with backstepping, an auto disturbance controller for nonlinear systems with three types of uncertainties including nonlinear uncertainties, unmeasured dynamics uncertainties and parametric uncertainties is proposed. Different from the existing robust adaptive control approach, the proposed scheme makes no difference between the uncertainties. Extended state observers are constructed to deal with the total uncertainties, meanwhile, the differentiators are applied to avoid the explosion of complexity in traditional backstepping design. In addition, a dynamic signal is introduced to dominate the unmeasured dynamics uncertainties. Based on Lyapunov stability analysis, it is proved that the designed controller can guarantee the output to converge an arbitrary small region around the reference signal. Simulation studies illustrate the effectiveness of the proposed method.