WK503

PC BASED STEPPER MOTOR CONTROL FOR ROBOTIC APPLICATIONS

ABSTRACT:

Robotics is interesting domain in the present engineering world. Here this project describes how to control a stepper motor using PC. This project is very useful in Robotics, for the Arm moment of the Robot and to move the robot forward and backward direction.

MAX232 IC is used for RS232 communication in this project.One of the 8051s many powerful features is its integrated UART, otherwise known as a serial port. The fact that the 8052 has an integrated serial port means that you may very easily read and write values to the serial port. If it were not for the integrated serial port, writing a byte to a serial line would be a rather tedious process requiring turning on and off one of the I/O lines in rapid succession to properly "clock out" each individual bit, including start bits, stop bits, and parity bits.

However, we do not have to do this. Instead, we simply need to configure the serial ports operation mode and baud rate. Once configured, all we have to do is write to an SFR to write a value to the serial port or read the same SFR to read a value from the serial port. The 8052 will automatically let us know when it has finished sending the character we wrote and will also let us know whenever it has received a byte so that we can process it. We do not have to worry about transmission at the bit level--which saves us quite a bit of coding and processing time.

Of all motors, step motor is the easiest to control. Its handling simplicity is really hard to deny - all there is to do is to bring the sequence of rectangle impulses to one input of step controller and direction information to another input. Direction information is very simple and comes down to "left" for logical one on that pin and "right" for logical zero. Motor controlis also very simple - every impulse makes the motor operating for one step and if there is no impulse the motor won't start.

Pause between impulses can be shorter or longer and it defines revolution rate. This rate cannot be infinite because the motor won't be able to "catch up" with all the impulses.

The key to driving a stepper is realizing how the motor is constructed. A diagram shows the representation of a 4 coil motor, so named because 4 coils are used to cause the revolution of the drive shaft. Each coil must be energized in the correct order for the motor to spin.

In this project, the stepper motor can be rotated in clock wise and anti-clock wise direction with 5 or 10 steps spin. This direction can be controlled by giving a command through PC’s hyper terminal tool. This project is also useful for positioning of Antenna.


BLOCK DIAGRAM:

Hyderabad: Tarakarama Estates, 2ndLeft Lane – Opp. RS Brothers, Ameerpet, Hyderabad-500073