I've been using 3 steppers with the accelstepper and an arduino.
The issue I have right now is that accelstepper decides which direction to run the motor depending on the position command, ie if current position is 5 and the next commanded position is 4 accelstepper will go back one.
What I need is for the code to only run the stepper in one direction regardless of what position is required.
I sussed it in the end.
Because accelstepper uses a long integer for the position I can get a lot of rotations before rolling over, so I just add the next value to the last plus 1 complete revolutionsworth of steps, the result is that the motor positions itself correctly and allways goes one way.
I might be able to reset the position integer in other infrequently run parts of the code.