Output regulation for an unstable wave equation with output delay and one measurement only
Shen Wang, Zhong-Jie Han, Shuangxi Huang, Zhi-Xue Zhao
TL;DR
The paper tackles output regulation for a 1D unstable wave equation subjected to output delay and unknown disturbances. By translating the regulation problem into stabilization via regulator equations, it designs a backstepping-based feedforward regulator and partitions time into delay-free and delay-active intervals to stabilize the system. An adaptive, infinite-dimensional observer—built from a dynamic compensator and an adaptive internal model—tracks the unknown disturbance frequency, while a single-measurement error-based feedback controller ensures exponential convergence of the tracking error $e(t)$ to zero. The work provides a pioneering, first-of-its-kind solution for output regulation of distributed parameter systems with output delay, supported by numerical simulations.
Abstract
This paper addresses the output regulation problem for a one-dimensional unstable wave equation subject to output delay and all-channel disturbances with unknown frequencies and amplitudes. First, this problem is transformed into a stabilization problem for an unstable wave equation with output delay and disturbances by employing regulator equations. Subsequently, a backstepping-based feedforward regulator is proposed to exponentially stabilize this system. To track the states of the unstable wave equation, the time interval is partitioned into two segments. The observers and predictors are designed at these distinct intervals, respectively. Therein, the observers comprise two components: a state observer proposed via dynamic compensators and an adaptive observer designed by the adaptive internal model method. Finally, a novel error-based feedback controller is derived using a single measurement, ensuring exponential convergence of the tracking error to zero. This work establishes the pioneering solution to the output regulation problem for distributed parameter systems (DPS) with output delay. Numerical simulations are provided to illustrate the results.
