A stepper motor controller

Open loop control of stepper motors suffers from a major disadvantage that the rotation of the rotor becomes oscillatory and unstable in certain speed ranges. The paper presents the microstepping technique which overcomes the problem of instability and at the same time provides for high accuracy of microstepping applications. This technique improves electronically the resolution of stepper motors and suppresses oscillations due to effects of mechanical resonance. Another key feature is the capability of the controller to control multiple number of stepper motors for simultaneous operations (independent and/or synchronized). This has greatly enhanced its usefulness in modern control applications. >