I'd like to assemble a prototype of brushless servo system using a RC brushless motor (heavily geared down), a sensored Electronic Speed Controller for RC motors, and a microcontroller to do the PID control.

Brushless motor and sensored ESC

I'd add three Hall sensors around the motor, and feed those signals into the ESC and the microcontroller. The MCU will run a PID controller, and output an RC servo compatible PWM signal to the ESC.

Question: Is this likely to work, or will I find that the ESC is trying to be clever? I have one RC car which only switches into reverse if you double pulse the reverse signal.

(Note, the reason I'm trying to get this working using an off-the-shelf ESC, rather than designing my own proper one is that development time is much more expensive than parts cost at the moment).

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    $\begingroup$ Can you provide datasheets for your components? My gut feel here is as you suggest that the ESC's input is going to be very low bandwidth and limit your control. What's your application? What sort of performance are you looking for? Why not buy an off-the-shelf brushless servo controller? $\endgroup$
    – Guy Sirton
    Sep 28, 2013 at 6:40
  • $\begingroup$ @GuySirton - Sadly, these kind of RC components often don't have datasheets. They're just listed on e-bay with their specs. $\endgroup$ Sep 28, 2013 at 8:05
  • $\begingroup$ @GuySirton - The reason I decided against an off-the-shelf solution is that I need a very good power:weight ratio. That's the reason I'm using brushless motors. Off-the-shelf controllers tend to be massive, and I loose all the weight advantage. $\endgroup$ Sep 28, 2013 at 8:06
  • $\begingroup$ How about something like this: elmomc.com/products/Tweeter-digital-servo-drive.htm $\endgroup$
    – Guy Sirton
    Sep 28, 2013 at 19:13
  • $\begingroup$ @GuySirton - Now why didn't Google show me that before? I've only spent a week searching for brushless servo drives! Those look pretty cool, but I'd need the Whistle which is a little on the heavy side for my application. $\endgroup$ Sep 28, 2013 at 19:55


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