高频增益未知的受扰非线性系统输出反馈控制

Output feedback control of perturbed nonlinear systems with unknown high-frequency gains

针对一类具有未知定常参数,包括未知高频增益的受扰非线性最小相位系统,给出了一种鲁棒自适应输出反馈控制策略．系统所受的干扰假设有界,但其界值是未知的．通过采用自适应策略来对其界值进行在线估计,控制算法并不需要高频增益符号的先验知识．同时,系统中的非线性项并不要求满足增长性条件和匹配条件．算法使得估计参数量达到了最小,保证了闭环系统所有信号的有界性,同时使得跟踪误差渐近收敛于零．

A robust adaptive output feedback control scheme is proposed for a class of perturbed nonlinear minimum phase systems with unknown constant parameters, including the high-frequency gain. The disturbances in the system are assumed to be bounded with unknown values. The adaptive laws are then employed to estimate them online. The control method does not require a priori knowledge of the sign of the unknown high-frequency gain. Furthermore, the restrictive growth and matching conditions on system nonlinearities are removed. The number of parameter estimates is minimal in the adaptive system. It is proved that under the proposed control scheme, all the closed-loop signals are bounded and the tracking error asymptotically converges to zero.