I was hoping to get a little insight on accurately measuring the current on 6 servo motors on a robotic arm. I will be using a MiniMaestro12 and 6 ACS724LLCTR-05AU current sensors with an Arduino Giga controlling the Maestro and reading the sensors. Would it be best to sample motors while they are receiving the PWM position signal or just take lots of samples and average them? Also, once all servos are powered up and receiving position signals, does the Maestro deliver the leading edge of all 6 servo position signals at once or in succession? How much of an effect does PWM dead time have on current?
Any resources you could share would be greatly appreciated.
Hello.
Unlike sending a duty-cycle based PWM signal to a brushed DC motor driver, the pulse width output from the Maestro is not used to directly drive the servos; each servo’s internal electronics read the pulse width position signal, process it, and drives the servo’s motor according to its own algorithm. So, the dead time of the pulse width signal should not really have any affect on current (servos are typically designed to accept a standard 50Hz signal), and I suspect just taking continuous samples and averaging them is probably going to be the most practical solution for you.
Because of what I described above, I do not think the details of how the Maestro sends the servo signals are helpful, but just in case, they are done sequentially.
Brandon
Thank you, I appreciate your help and the very useful information regarding servo operation.
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