AVR446: Linear speed control of stepper motor
Features
• Linear speed control of stepper motor
- Control of acceleration, deceleration, max speed and number of steps to move
• Driven by one timer interrupt
• Full- or half-stepping driving mode
• Supports all AVR® devices with 16bit timer
• Demo application for ATmega48 running on 3,68MHz, with serial interface on 19200
8/N/1.
1 Introduction
This application note describes how to implement an exact linear speed controller
for stepper motors. The stepper motor is an electromagnetic device that converts
digital pulses into mechanical shaft rotation. Many advantages are achieved using
this kind of motors, such as higher simplicity, since no brushes or contacts are
present, low cost, high reliability, high torque at low speeds, and high accuracy of
motion. Many systems with stepper motors need to control the acceleration/
deceleration when changing the speed. This application note presents a driver with
a demo application, capable of controlling acceleration as well as position and
speed.
This linear speed controller is based on an algorithm presented in ‘Embedded
Systems Programming’ January 2005, ‘Generate stepper-motor speed profiles in
real time’ an article by D. Austin. This algorithm allows parameterization and
calculation in real time, using only simple fixed-point arithmetic operations and no
data tables.
Figure 1-1. Stepper motors
8-bit
Microcontrollers
Application Note
Rev. 8017A-AVR-06/06
