Quote Originally Posted by Robin Hewitt View Post
The perfect current for stepper motor coils would be two sine waves 90 degrees out of phase. Simple drivers approximate to it, pukka drivers try to create it. Intermediate points are a bit springy but rotating a component is a no load situation so tiny changes in angle are possible if your driver is willing and able
For this requirement, where full rotation isnt required, i guess, but accurate partial rotation is, I wonder there would be mileage in a purpose built sinewave phased driver rather than a stepper driver as such? The load is small but not zero.. presumably you'd be rotating the suction head which would have a vacuum tube attached which would give some tangential load.