Electric braking

Let's Make Robots
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1

I'm working on an RC car and was thinking about the braking. The idea is: I'm driving at full speed and need to turn. Obviously, because my car is going to break the land speed limits ( ;) ), it cannot take the turn at full speed so I'll need to slow down. Now, just releasing the throttle won't be enough, so I'll have to brake extra somehow. I was thinking about giving slight reverse throttle, so that with PWM, I can handle the braking intensity. Now I don't know what this would mean current-wise. I know this will kind of short-circuit the motor (motor makes its own voltage when rotating, so when you apply a voltage in the different direction, you short-circuit it). I don't know however what currents I'd might me expecting. The motor will run at 8V, draws 1.5A cont without load, 15A when stalled.

Anyone with experience in this department?

2

Yup.

This is very doable and probably with what you already have. I had not done any braking until I got a hold of the Wild Thumper controller and now it seems, I can’t live without this feature.

Check my math on this, but it seems that you simply need to run your PWM signal to both your driver pins at the same time instead of PWM on one pin and say, low on the other. This working or not working can depend on the layout of your motordriver (the L293 for example, is effected by the enable pin and how it is wired) but should be simple to figure out.