24-09-2014, 03:38 PM
Abstracts: A stepper motor translates current pulses into motor rotation. A typical motor contains four winding coils. The coils are often labeled red, yellow/white, red/white and yellow, but may have other colors. Applying voltage to these coils forces the motor to step one step. In normal operation, two winding coils are activated at the same time. The stepper motor moves clockwise one step per change in winding activated. If the sequence is applied in reverse order, the motor will run counterclockwise. The speed of rotation is controlled by the frequency of the pulses. Every time a pulse is applied to the stepper motor the motor will rotate a fixed distance. Stepper motors are one of the most versatile forms of positioning systems. 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. This project presents the micro stepping technique which overcomes the problem of instability and at the same time provides high accuracy for micro stepping applications. This technique improves electronically resolution of the stepper motors and suppresses oscillations due to effects of mechanical resonance. This has greatly enhanced its usefulness in modern control applications. The Control Program is developed in C language and Keil compiler is used to converts this control program into executable file or say in a HEX code.