Overactuation for Active Damping in Compliant Positioning Stage using Piezoelectric Transducers

Abstract

Integrating compliant mechanisms into high-precision motion systems has facilitated the development of lightweight and frictionless designs. However, these systems often face challenges related to low-frequency parasitic resonance modes and limited structural damping, leading to compromised position accuracy and restricted control bandwidth. While notch filters are conventionally used to suppress these parasitic resonance peaks and enable higher control bandwidths, undesired effects persist in closed-loop disturbance rejection performance. To address this limitation, researchers have explored the concept of overactuation, employing a greater number of actuators than the number of rigid body modes to be controlled.
This approach allows for additional closed-loop feedback interconnections, offering
increased freedom to enhance performance. This research presents a novel overactuation based solution where: (1) the use of additional actuators enables the implementation of active damping control to improve closed-loop disturbance rejection performance and (2) the integration of multiple distributed piezoelectric bender actuator-sensor pairs in a collocated configuration enhances damping performance. A mathematical framework is formulated to demonstrate the benefits, and an experimental setup is constructed to validate the numerical findings and serve as a proof of concept. The proposed solution effectively suppresses the
parasitic resonance mode, enhances disturbance rejection on the end-effector, and enables higher control bandwidth in the positioning system.