Hi,
Once you select a given speed the dc motors run in the required direction sequentialy (e.g. motor 1, 2 turns cw and motor 3 ,1ccw)
As soon they touch the hall sensors the required times, they stop immediately, so there is no loading of the m
This is the critical point.
If a DC motor is powered....what stops it?
Does for instance, once the gear is selected, does it have a mechanical stop that prevents the motor from turning or otherwise overdriving?
If the motor stalls because its traveled as far as it can does it draw excessive current? How long could that situation be tolerated?
There is little point in trying to devise a control strategy until you know EXCATLY how the controlled parts, namely the DC motors operate.
Just to flesh out an idea......which may or may not be applicable depending on the answers to the questions:
Imagine the power supply to each motor being current limited, such that should the motor stall by virtue of it coming up against a mechanical stop
OR the gears not lining up internally such that the motor cannot complete the gear change without the spindle rotating a small amount to allow the gears to mesh,
then the current would be low enough that no damage be done, at least for 20 seconds or so.
Electric windows in cars work that way. If the window stalls, ie it has reached the end of travel OR some unfortunate has his arm stuck in the window the motor will
stall thereby drawing more current, which is measured by the driver circuit and turns off the supply to the motor. This saves the motor and wiring from damage
but also provides a measure of safety should someones arm be caught.
I imagine a control setup something like pictured. I have shown only one of the gear select motors. The selection/synchronisation can be handled programmatically
by Mach or by an Arduino.....whichever seems easiest.
Craig