Feedback control of vibration with inertial actuators
Feedback control of vibration with inertial actuators
The behaviour of an inertial actuator is analysed with different inner feedback control schemes. First, it is shown that a phase-lag controller in the inner loop, based on the measurement of the transmitted force, can be used to significantly improve stability margin and performance of the system using relatively low gains.
The use of integral displacement feedback as an inner loop can provide self-levelling capabilities for the inertial actuator thus overcoming the static deflection problem. A novel device for active vibration control, based on an inertial actuator with a proof-mass displacement sensor and inner PID controller, is described and its performance is demonstrated experimentally. It is found that the effective natural frequency and damping of the actuator can also be changed substantially with such a controller, thus allowing an inertial actuator to be customised for a specific application.
The stability and performance are then analysed for an active isolation system using the modified inertial actuator and an outer velocity feedback control loop. The plant response, from force actuator input to sensor output, is derived in terms of the mechanical mobilities of the equipment structure being isolated and the vibrating base structure, and the mechanical impedance of the intervening mount. The results of an experimental study of active vibration isolation using a modified inertial actuator are then described. Theory and experiments agree well, demonstrating the effectiveness of the modified inertial actuator in isolating a piece of equipment from a vibrating base.
In the second part of the thesis, strategies for the suppression of plate vibration are investigated by considering the equivalent impedance of power-minimising feedforward vibration controllers. The minimum power, transmitted to infinite and finite plates by a single primary force and a single secondary force, optimised at each frequency, has been compared with the power reduction that can be achieved with passive vibration treatments. The equivalent impedance is defined to be the ratio of the optimised secondary force to the total velocity at the secondary force location, but it is generally non-causal and so cannot be implemented for broadband random excitations. The approximation of the equivalent impedance by lumped parameter systems is considered. In particular, passive controllers, based on springs and dampers, have been analysed, although, in many practical applications, a rigid ground is not available to react these components off.
University of Southampton
Benassi, Luca
8c692f93-93eb-454e-b0b7-75f216038523
2004
Benassi, Luca
8c692f93-93eb-454e-b0b7-75f216038523
Benassi, Luca
(2004)
Feedback control of vibration with inertial actuators.
University of Southampton, Doctoral Thesis.
Record type:
Thesis
(Doctoral)
Abstract
The behaviour of an inertial actuator is analysed with different inner feedback control schemes. First, it is shown that a phase-lag controller in the inner loop, based on the measurement of the transmitted force, can be used to significantly improve stability margin and performance of the system using relatively low gains.
The use of integral displacement feedback as an inner loop can provide self-levelling capabilities for the inertial actuator thus overcoming the static deflection problem. A novel device for active vibration control, based on an inertial actuator with a proof-mass displacement sensor and inner PID controller, is described and its performance is demonstrated experimentally. It is found that the effective natural frequency and damping of the actuator can also be changed substantially with such a controller, thus allowing an inertial actuator to be customised for a specific application.
The stability and performance are then analysed for an active isolation system using the modified inertial actuator and an outer velocity feedback control loop. The plant response, from force actuator input to sensor output, is derived in terms of the mechanical mobilities of the equipment structure being isolated and the vibrating base structure, and the mechanical impedance of the intervening mount. The results of an experimental study of active vibration isolation using a modified inertial actuator are then described. Theory and experiments agree well, demonstrating the effectiveness of the modified inertial actuator in isolating a piece of equipment from a vibrating base.
In the second part of the thesis, strategies for the suppression of plate vibration are investigated by considering the equivalent impedance of power-minimising feedforward vibration controllers. The minimum power, transmitted to infinite and finite plates by a single primary force and a single secondary force, optimised at each frequency, has been compared with the power reduction that can be achieved with passive vibration treatments. The equivalent impedance is defined to be the ratio of the optimised secondary force to the total velocity at the secondary force location, but it is generally non-causal and so cannot be implemented for broadband random excitations. The approximation of the equivalent impedance by lumped parameter systems is considered. In particular, passive controllers, based on springs and dampers, have been analysed, although, in many practical applications, a rigid ground is not available to react these components off.
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Published date: 2004
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Local EPrints ID: 465182
URI: http://eprints.soton.ac.uk/id/eprint/465182
PURE UUID: 3c251d22-abaa-4f33-a177-c6ec31e34b8a
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Date deposited: 05 Jul 2022 00:27
Last modified: 16 Mar 2024 20:00
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Author:
Luca Benassi
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