Re: [avr-chat] OT: Motor vibration due to PWM harmful?

[Erik Christiansen]

On Thu, Oct 26, 2006 at 10:04:40AM -0400, Christopher X. Candreva wrote:
> 
> This is a subject that has come up a few times in comp.robotics.misc , along 
> with solutions for stopping it, that I don't fully remember now.

Ah, thanks Christopher.

That was more focused than scouring umpty thousand hits in general
google-land. Still, another hundred hits later, I've managed to miss any
direct reference to the problem, even with just "pwm vibration".

I did find double LC filtering used on the intersil HIP4081A (H-bridge
driver) evaluation board, so someone found it useful.

I'm tempted to just use the OC1x & /OC1x complementary PWM outputs of
the ATtiny26 to drive the series pass element and synchronous rectifier
of a buck dc-dc converter, so the motor receives dc, and there's no
squeal. Having a tube of 25A relays in the junkbox, I may just take the
easy way out on motor reversing.

Erik