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Designing Voice Coil Actuator with Flexures

Posted May 17, 2012, 10:54 p.m. EDT Low-Frequency Electromagnetics, Structural Mechanics Version 4.2a 3 Replies

thomas014
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Hi,

I am new to comsol and am trying to design a linear voice coil actuator by fixing each end to two diaphragm flexures, therefore keeping everything axisymmetric. I have designed the flexures with the structural mechanics and have placed loads and found eigenfrequencies. I am wanting to know how to incorporate a voice coil actuator to drive the flexures? I searched for some similar models without any luck. The ideal setup would be applying some step function to the voice coil and get the response of the system, and tune it with a PID controller. Any help whatsoever would be great as I am just getting used to the new software.

Thanks!
3 Replies Last Post May 18, 2012, 3:44 p.m. EDT
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago May 18, 2012, 3:54 a.m. EDT
Hi

I would say start making another model with MF, with a coil, a magnet, some iron AND the air around, then solve that, then only, mix both models into one

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Good luck
Ivar
Hi I would say start making another model with MF, with a coil, a magnet, some iron AND the air around, then solve that, then only, mix both models into one -- Good luck Ivar
thomas014
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Posted: 1 decade ago May 18, 2012, 2:00 p.m. EDT
Thanks Ivan. There were some good tutiorials to help get me startd. As far as the flexure how do I go about getting a frequency response (dB vs Hz)? I tried a study with my flexure on th frequency domain but was having some problems.
Thanks Ivan. There were some good tutiorials to help get me startd. As far as the flexure how do I go about getting a frequency response (dB vs Hz)? I tried a study with my flexure on th frequency domain but was having some problems.
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)
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Posted: 1 decade ago May 18, 2012, 3:44 p.m. EDT
Hi

I believe that was a good choice for the method. Often frequency domain studies of mechanical resoannace structures are delicate because there is no damping so the resonance has a high Q factor and the solver does not manage to follow the steep rise and fall of the resonance. Two ways out, that I have tested sucessfully: 1) add some damping this makes your Bode plot more reasonable with smooth phase transitions, 2) selecta strict time stepping and detect your resonances by a first eigenfrequency analysis, then manually change the time stepping to become very fine around these resonance frequencies to help the solver pass the resonance peaks.

I believe there are a few examples in other threads too on the FORUM

--
Good luck
Ivar
Hi I believe that was a good choice for the method. Often frequency domain studies of mechanical resoannace structures are delicate because there is no damping so the resonance has a high Q factor and the solver does not manage to follow the steep rise and fall of the resonance. Two ways out, that I have tested sucessfully: 1) add some damping this makes your Bode plot more reasonable with smooth phase transitions, 2) selecta strict time stepping and detect your resonances by a first eigenfrequency analysis, then manually change the time stepping to become very fine around these resonance frequencies to help the solver pass the resonance peaks. I believe there are a few examples in other threads too on the FORUM -- Good luck Ivar

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