Event-Triggered Adaptive Trajectory Tracking Control for Hysteretic Nonlinear Systems With Fixed-Time Performance
针对存在未知迟滞的非严格反馈非线性系统，提出一种固定时间事件触发输出反馈控制方案，通过构建HT-NARMAX模型描述迟滞行为，并设计改进状态观测器与自适应事件触发控制器，保证系统在固定时间内收敛并降低通信负担。
In this study, a fixed-time event-triggered output feedback control scheme is presented for the nonstrict-feedback nonlinear systems subject to unknown hysteresis. A nonlinear auto-regressive moving average with the hysteresis term (HT-NARMAX) model is constructed to describe the hysteresis behavior. On this basis, a modified state observer is designed to estimate the unavailable states and unknown parameters of the HT-NARMAX model simultaneously. Then, by combining the command filter technique and event-triggered mechanism, a novel fixed-time adaptive event-triggered control (FAETC) strategy is proposed. In FAETC, the tracking differentiator with an unique acceleration function (UTD) is developed to mitigate the computation complexity problem, and the ETC is used to reduce the communication burden. Furthermore, to guarantee the system convergence, a new fixed-time stability criterion is set up by resorting to a scaling function. In view of this criterion, all signals in the closed-loop system can achieve the fixed-time convergence. Moreover, the tracking performance can be retained over a fixed time via the reported controller. Finally, the control performance of the presented approach is verified by a pizoelectric-driven micropositioning stage (PDMPS).