Self-Recovery and Fault-Tolerant Control of Distributed Piezoelectric Stack Actuators Under Temperature Perturbation and Layer Breakdown

Aerospace actuators must deliver high-speed, high-precision performance while withstanding extreme temperatures and environmental variations, which pose significant challenges to their positioning accuracy and reliability. To address these issues, this article proposes a fault decoupling and fault-tolerant control (FTC) scheme for distributed piezoelectric stack actuators (PSAs), enabling self-diagnosis and self-recovery. A temperature perturbation observer (TPO) is designed to estimate temperature-induced disturbances, and a fault decoupling sliding mode observer (FDeSMO) is developed to decouple layer breakdown faults from lumped disturbances. The coordination between the two observers allows accurate detection of broken layers under temperature variations. Subsequently, a fault-tolerant controller is integrated to reallocate control signals and ensure system stability. Experimental results validate the proposed scheme, demonstrating its ability to detect fault and maintain reliability under the fault occurrence and temperature variation ( $\textbf{19}\!\boldsymbol{\sim}\!\textbf{60}\,{}^{\boldsymbol{\circ}}\textbf{C}$ ). Furthermore, the error convergence time after fault detection can be controlled within 8.7 ms. The root mean square error (RMSe) remains below 0.536 $\boldsymbol{\mu}$ m, accounting for 5.36% of the sinusoidal reference ( $\textbf{1}\!\boldsymbol{\sim}\!\textbf{100}\,\textbf{Hz}$ , $\textbf{1}\!\boldsymbol{\sim}\!\textbf{10}\,\boldsymbol{\mu}\textbf{m}$ ).