Tips for smooth, constant speed?

Other Hardware Motors, Mechanics, Power and CNC
1

I've messed around with steppers before. For my first "practical" project, I want to build a clock drive for my telescope. This requires driving a shaft at a precise speed of a few rotations per day, with minimal vibration. Secondary concerns include minimizing sound and maximizing battery life, in that order.

As far as the motor controller goes, what's the best way achieve smooth rotation and precise speed? Am I better off running the motor at a higher speed and gearing it down more? If I do run it at high speed, would there still be any value to microstepping? And on the mechanical side, would the slight elasticity of a toothed belt help smooth out the output speed?

2

While "messing around" with stepper motors, did you notice they move and stop and then move again. Would you call this a smooth constant speed? I would not either. Best to use a motor that at least has a chance of smooth constant speed and then gearing it down to get the shaft speed you require.

Paul

3

Just use lots of microstepping, like x100 or x256, it will be smooth.

4

Or add a mass (flywheel) to the motor shaft, the inertia of which will assist in eliminating any jogging effect though such inertial effects might be detrimental to precise positioning