Stepper Motor Assembly

1
Stepper Motor Assembly

• By
• Ron Lazarowicz, Nathan Light and Allen Fields
• Engineering 335 Technical Communication
• Olivet Nazarene University
• April 27, 2004

2
Problem Statement

• Develop a motor control system to rotate a table.
• Table must turn one full rotation and must also
  move in adjustable small increments.

3
Scope

• Cover the design of a stepper motor system.
• Does not discuss theory behind stepper motor
  design.
• Does not discuss the internal workings of the
  integrated circuits.

4
Definitions

• Stepper Motor a motor that moves in portions of
  a full revolution
• Micro controller integrated cpu and peripheral
  device

5
Background

• Stepper Motor
• Consists of coils surrounding permanent magnet
• Energizing coils in sequence turns the motor
• Applications
• Printers
• Plotters
• Robots
• Floppy disk drives

6
Background (contd)

• Stepping sequences

7
Background (contd)

• Rotary table

8
Background (contd)

• Pulleys

9
Functional Requirements

• Two modes
• Automatic
• Manual
• Automatic
• Specify speed and direction
• Rotate motor until position sensor is activated

10
Functional Requirements (contd)

• Manual
• Specify direction
• Specify number of steps
• Specify speed of rotation
• Begin rotation until number of steps has been
  satisfied

11
Detailed Design

• MAX232 - RS232 driver/receiver chip
• Converts RS232 logic levels to TTL standards and
  TTL to RS232 standards
• PIC16F877 - Micro controller chip
• Receives RS232 signal from MAX 232
• Converts control signals into pulse sequences
• Provides signals for power stage

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Detailed Design (contd)

• L293 H-bridge driver
• Converts signals from micro controller to drive
  bipolar permanent magnet motors
• Rotates table
• Computer software
• Written in Visual Basic 6.0
• Micro controller software
• Written in Bytecraft C compiler

13
Detailed Design (contd)

• Command Set
• M Sets manual mode
• A Sets automatic mode
• O Stops motor
• Commands are followed by detailed information to
  describe desired action
• Micro controller sends a character to the
  computer to signify the motors activity or lack
  thereof.

14
Design Verification

• After selecting mode of operation, motor carries
  out commands
• Testing confirmed clockwise and counterclockwise
  rotation
• Testing also confirmed Manual and automatic
  operation
• Advantages
• Few components needed
• Assembly costs are low
• High reliability
• Little space required

15
Safety

• Be VERY careful with soldering iron!!!!
• Personal Protection Equipment needed
• Safety glasses