Development and fault-tolerant control of a distributed piezoelectric stack actuator

Piezoelectric stack actuator (PSA) has attracted widespread attention in aerospace applications. However, the severe operating conditions would bring certain risks to PSA, leading to decreased performance or even failure. The conventional PSA structure lacks adaptability in the event of a complete failure occurring within the piezoelectric stack layer (PSL) due to its centralized design and driving method. To address the reliability challenges inherent in PSAs, this paper proposes a novel distributed PSA (DPSA) by means of mechanical and electrical dispersion. Additionally, dual-redundant PSLs are integrated into the DPSA as backups, providing hardware redundancy for active fault-tolerant control (FTC). Building upon this foundation, an sliding mode observer (SMO)-based fault detector for DPSA is developed to facilitate fault reconstruction. Subsequently, an active FTC strategy, comprising dual-SMO-based fault detectors and a tracking controller, is introduced to effectively manage faults and reallocate control resources. Comprehensive experiments under various fault scenarios are carried out to assess the performance of the SMO-based fault detector and FTC strategy. The results demonstrate that the proposed fault detector and FTC strategy promptly detect faults and efficiently restore the DPSA to a stable state, thereby ensuring effective trajectory tracking even in the presence of faults.