Discussions

any way to sync the speed of motors or adjust the output of ESC's?

Posted by Mike Mogenson on June 21, 2010 at 1:40pm

I have two identical pairs of ESC & brushless motor combinations. The ESC's spin both motors at different speeds for the same duty cycle. I'm using an arduino and the analogWrite() function to send PWM signals to each ESC. An input of 127 equals 50% duty cycle and 0 throttle and an input of 255 equals 100% duty cycle and max throttle. The difference in motor speeds is not constant across the full range of throttle levels and because I only have 128 steps of resolution I can't get the motor speeds to match with any pair of integer throttle levels.

Is there any way to trim/match/sync ESC response? I have Turnigy ESC's and motors.

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Replies

Moderator

Nathaniel Caner June 22, 2010 at 1:57pm

Mike,

This may seem simple, but have you tried to swap the ESCs to try to isolate where the issue is? For example if the slower rpm follows the ESC then you know it's the ESC, if not, then you eliminate the ESC.
Developer

Ryan Beall June 21, 2010 at 8:44pm

I don't think you "tune" ESC's. You are seeing the slight variation in KV of the motors as well as pitch of the blades. You really just need to get more resolution out of the arduino. You might try tricking it to get more resolution. Say one motor is your perfect at 50% =127 and the other motor is low at 127 and high at 128. So just alternate between 127 and 128 on the second motor. Should cause the same affect but only at half the frequency. It's fine if you arn't doing quad rotor stuff

-Beall
Greg Fletcher June 21, 2010 at 8:08pm

Buy some good Castle Creations ESC's They are made in USA and are high quality. They are also programmable and can be set to RPM mode.
here
Also you need to look at the arduoilot code under the servo tab. The set up the PWM outputs and have much higher resolution. Using analogeWrite() is not the way to go for driving a servo. This has been done before, you just need to look at the code. here
Or what Dr. Mike said.