Thesis-2008-Voronina.pdf (39.55 MB)
Modelling of autoresonant control of an ultrasonic transducer for machining applications
thesis
posted on 2013-08-06, 13:56 authored by Svetlana V. VoroninaThe main purpose of this research is an investigation into the different strategies for the
autoresonant control of an ultrasonic transducer. Numerical simulations were considered
as the most appropriate method for analysis and a Matlab-Simulink computer model of a
non-linear ultrasonic vibrating system with the possibility of autoresonant control was
developed. The controlled system consists of two modules, the first of which is an
electromechanical model of the ultrasonic transducer comprising a piezoelectric
transducer and a step concentrator. The second module simulates influence from the
machining process. The coefficients of the electromechanical model were calculated
through an identification process based on the real measurement of the ultrasonic
transducer's vibrations. The validity of the computer model of the ultrasonic vibrating
system has been confirmed experimentally. Further, a numerical model of the
autoresonant control of this system has been developed. The autoresonant control
maintains the resonant regime of oscillation by means of positive feedback, which
provides excitation, transformation and amplification of the control signal from a
feedback sensor. Stability of the control is sustained by additional regulation of an
amplification ratio by the use of a local negative feedback. The model allows the
exercise and comparison of three control strategies. The first one is based on the
feedback signal proportional to the displacement of the end of the concentrator
(mechanical feedback). The two other types of control are based on the signals
proportional to the electrical characteristics of the piezoelectric transducer (electrical
feedback). One of these strategies uses the current in the piezoceramic rings as the
control signal (current feedback). The last control strategy takes into account both the
current and the power of the piezoelectric transducer (power feedback). The completed
investigation revealed the advantages and drawbacks of each of these control strategies.
The results of the simulation are presented and discussed. To validate the results
obtained through numerical simulations, a prototype of an autoresonant control system
was developed and manufactured. For all the listed control strategies the machining
experiments have been conducted with the control system. Experiments confirmed the
results of the simulation.
History
School
- Mechanical, Electrical and Manufacturing Engineering
Publisher
© S.V. VoroninaPublication date
2008Notes
A Doctoral Thesis. Submitted in partial fulfilment of the requirements for the award of Doctor of Philosophy of Loughborough University.Language
- en