This paper describes an investigation into an active four-mount vibration isolation system for a three-dimensional equipment structure, and is focused, in particular, on the physical aspects and mechanisms of control, including stability issues. Piezoelectric actuators are used as the control actuators of the active vibration isolation system for convenience, and are installed in parallel with each of four mounts placed between a piece of equipment and a flexible base structure. The control strategy used is decentralised velocity feedback control, where each actuator is operated independently by feeding back the corresponding equipment vibration velocity at the same location. Particularly, isolation of low-frequency vibration is considered where the equipment can be modelled as a rigid body and the mounts as springs and dampers. Although one end of the actuator acts at the sensor position on the equipment, the system is not collocated because of the reactive force at the other end acting on the flexible base structure, whose dynamics may be strongly coupled with the mounted equipment. The investigation of this actuator installation and its practical implementation are the motivation of this research. A general theoretical formulation for analysing multiple-mount vibration isolation systems using the impedance method is presented and is used to investigate the control mechanisms involved. A proof of unconditional stability is given in this research through the use of the Nyquist criterion. The maximum allowable gain is also analytically addressed for a control system having a time delay in the control loop.

An Active Vibration Isolation System for a 3-D Equipment Structures / Pasquino, Mario; Brigante, Michele; F., Fabbrocino; Modano, Mariano. - (2005). (Intervento presentato al convegno XVII Convegno AIMETA tenutosi a Firenze nel 11-15 settembre 2005).

An Active Vibration Isolation System for a 3-D Equipment Structures

PASQUINO, MARIO;BRIGANTE, MICHELE;MODANO, MARIANO
2005

Abstract

This paper describes an investigation into an active four-mount vibration isolation system for a three-dimensional equipment structure, and is focused, in particular, on the physical aspects and mechanisms of control, including stability issues. Piezoelectric actuators are used as the control actuators of the active vibration isolation system for convenience, and are installed in parallel with each of four mounts placed between a piece of equipment and a flexible base structure. The control strategy used is decentralised velocity feedback control, where each actuator is operated independently by feeding back the corresponding equipment vibration velocity at the same location. Particularly, isolation of low-frequency vibration is considered where the equipment can be modelled as a rigid body and the mounts as springs and dampers. Although one end of the actuator acts at the sensor position on the equipment, the system is not collocated because of the reactive force at the other end acting on the flexible base structure, whose dynamics may be strongly coupled with the mounted equipment. The investigation of this actuator installation and its practical implementation are the motivation of this research. A general theoretical formulation for analysing multiple-mount vibration isolation systems using the impedance method is presented and is used to investigate the control mechanisms involved. A proof of unconditional stability is given in this research through the use of the Nyquist criterion. The maximum allowable gain is also analytically addressed for a control system having a time delay in the control loop.
2005
8884534593
An Active Vibration Isolation System for a 3-D Equipment Structures / Pasquino, Mario; Brigante, Michele; F., Fabbrocino; Modano, Mariano. - (2005). (Intervento presentato al convegno XVII Convegno AIMETA tenutosi a Firenze nel 11-15 settembre 2005).
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11588/309582
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