19-11-2012, 01:49 PM
MICROCONTROLLER BASED CLOCKWISE/ANTICLOCKWISE STEPPER MOTOR CONTROLLER USING PC KEYBOARD VIA COM PORT
1MICROCONTROLLER.doc (Size: 38.5 KB / Downloads: 34)
AIM:
The main aim of this project is to design Microcontroller Based Clockwise/Anticlockwise Stepper Motor Controller Using PC Keyboard via Com Port.
PURPOSE:
Computer controlled 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 paper 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.
DESCRIPTION:
In this project the microcontroller which forms the heart of the project, plays an important role in establishing communication between the pc and the microcontroller. In this system a unipolar stepper motor is used (which is used widely in all kinds of floppy drives and CD drives) the use of single microcontroller to control the speed, direction and rotation angle of a stepper motor by sending pulse sequences to the motor winding in response to the control commands. Commands executed by the code in this application include: single step the motor rotates in a clockwise or counterclockwise direction (i. e. rotate the rotor through a certain number of degrees) when the corresponding key is pressed from the computer keyboard. This is a general purpose application for which a degree of adjustment or programmability is required to meet the needs of specific processes and their performances. This project consists of a stepper motor and a driver IC ULN 2003 that will drive the motor, However the Microcontroller lacks sufficient current to drive the stepper motor windings, so driver ULN2003 (U3) is used to energize the stator, based on the instructions typed by the user in the pc the stepper motor will rotate. In the pc we will type a command and based on the command the stepper motor will work based on that command.