Internal Velocity Feedback for Stabilisation of Inertial Actuators for Active Vibration Control

Abstract

Collocated direct velocity feedback with point force actuators mounted on structures generates active damping and theoretically is unconditionally stable. When inertial actuators are used to generate the control force the actuator becomes unstable even for moderate velocity feedback gains. In this study an internal, relative velocity sensor is used to implement an additional feedback loop in a lightweight, electrodynamic, inertial actuator. It is found that when the internal loop is used in addition to the conventional external velocity feedback loop there is an ideal internal velocity feedback gain for which maximum vibration reduction is achieved through the external velocity feedback loop. Experiments and measurements are compared at the model problem of an inertial actuator attached to a clamped plate.