Reduced-Order Filters-Based Adaptive Backstepping Control for Perturbed Nonlinear Systems
针对一类含参数不确定性和时变有界扰动的非线性输出反馈系统，提出一种基于降阶滤波器的鲁棒自适应输出反馈控制方法，使输出跟踪误差收敛到预设小邻域内。
In this article, a robust adaptive output-feedback control approach is presented for a class of nonlinear output-feedback systems with parameter uncertainties and time-varying bounded disturbances. A reduced-order filter driven by control input is proposed to reconstruct unmeasured states. The state estimation error is shown to be bounded by dynamic signals driven by system output. The bound estimation technique is employed to estimate the unknown disturbance bound. Based on the backstepping design with three sets of tuning functions, an adaptive output-feedback control scheme with the flat-zone modification is proposed. It is shown that all the signals in the resulting closed-loop adaptive control systems are bounded, and the output tracking error converges to a prespecified small neighborhood of the origin. Two simulation examples are provided to illustrate the effectiveness and validity of the proposed approach.