Adding reverse function to a brushed motor electronic speed controller

Question

This is for a Hobby-weight (5.44 Kg) battle robot.

I bought two ESCs for my drive motors but the ESCs do not have a reverse function (or brake for that matter).

Is there any simple way I can achieve this through maybe either:

1. The R/C settings (setting middle position of joystick as stopped, top-wards as forward and bottom-wards as reverse?)

2. Or could I maybe achieve this using Arduino? I have a card with relay switches that I can use with the Arduino so am not worried about high voltage or current but I am worrying it could get messy..

I could just buy two new ESCs with the above features but they cost quite a bit more than the ones I already have so I would prefer to try a few tricks first - if there are any!

Answer 1

If your ESC does not provide reverse functionality, it will never do.

The "reverse" mode can be achieved in general by swapping any two motor cables. I would do this with the arduino setup in combination with your R/C settings. Arduino can easily get the RC information from a receiver.

Now it depends on your relays, you may achieve it with 2 relays, but if the relays are not the right ones you need 4 of them

Answer 2

To enable reverse, a popular design is to use an H-bridge (essentially a circuitry version of manually flipping the polarity of the wires) placed between your ESC and the motor. According to this answer, H-bridges are a normal part of an ESC output stage -- that your ESC appears to lack.

Although it could be built with relays, it may be better for your ESC and/or motors to select an appropriate semiconductor-based H-bridge. There are ICs available specifically for this purpose.