Local tuning of decentralised velocity feedback control systems

Abstract

This thesis presents a theoretical and experimental study on local tuning of velocity feedback control units with inertial actuators, for decentralised broadband vibration control of plates. The objective of this research is to develop a cost-effective active damping system, where the velocity feedback gain of each loop is adjusted locally. The optimal feedback gain, which guarantees a global reduction of vibration of the structure, is found by maximising the mechanical power absorption of each unit from the plate. In this way, the use of monitoring sensors is avoided, and a model of the structure to be controlled is not required. The implementation of the control system is further simplified by using inertial actuators, which can be directly mounted on the plate without the need for an external support to react off.

Two mathematical models are developed to analyse the proposed control system. A parametric study is carried out to investigate the effect of the actuator/plate pair on the performance of the control system, and the effect of different types of broadband disturbance. In addition, the feedback control system is shown to be robustly stable, even when experimentally measured parametric uncertainties are taken into account.

In the second part of the thesis, the study is extended to a multi-channel case, where more than a single unit is considered. The improvement in the reduction of vibration with a different number of control units is compared by considering the electrical power required by the system, and the results are shown to be similar to the ones obtained with a fully centralised feedback control system. Finally, the Inverse Nyquist-array method is used to guarantee the stability of the feedback control system, by defining a maximum stable feedback gain on each unit.

Measurements have been conducted on an aluminium plate with two independent control units to validate the proposed decentralised feedback control system, and the local tuning strategy is found to outperform the single-channel case, where only one unit is in use, not only in terms of vibration reduction, but also in power requirements.

More information

Identifiers

ORCID for Stefano Camperi: orcid.org/0000-0002-0543-0400

Catalogue record

Export record