Piezoelectric actuators often work in a close-loop feedback position control system due to hysteresis. Our objective is to make an actuator self-sense its output force and displacement without using extra sensor, which is termed self-sensing actuator/actuation (SSA). A compound circuit was proposed to voltage-drive the piezoelectric actuator and get the resulting charge concurrently. Based on the circuit, the unstressed actuator can self-sense its free strain. If the actuator is externally stressed, an observer was constructed to estimate the actuator's stress and strain state. The observer-based self-sensing approach is akin to state estimation techniques, depending on the fact that the electric field is controllable and the electric displacement is measurable. In order to compensate hysteresis, voltage versus charge relation was modeled sign GMS model, and the observer was improved to a nonlinear one. The observer-based SSA approach successfully bypasses the impedance mismatching problem bothering the bridge-based SSA approach. Experiments validated the approach.

Date Published: 14 September 2001
PDF: 4 pages
Proc. SPIE 4414, International Conference on Sensor Technology (ISTC 2001), (14 September 2001); doi: 10.1117/12.440145

Published in SPIE Proceedings Vol. 4414:
International Conference on Sensor Technology (ISTC 2001)
Yikai Zhou; Shunqing Xu, Editor(s)