29-Stepper motor control system based on 51 single chip microcomputer

Specific implementation functions

The system consists of STC89C52 single-chip microcomputer + single digital tube + LED indicator light + ULN2003 driver chip + DC-5V stepper motor.

Specific functions:

(1) Realize key control of stepper motor forward, reverse, acceleration, deceleration and stop;

(2) Two LEDs display forward and reverse rotation, and a 7-segment LED digital tube displays the current speed gear (9 gears in total);

(3) 4 red LEDs, indicating the motor speed.

design background

A stepper motor is an actuator that converts electrical pulse signals into angular displacement. The angular displacement of its rotor is proportional to the frequency of the input pulse, and a wide range of speed regulation can be achieved by changing the pulse frequency. At the same time, stepper motors are easy to interface with computers and other digital components, so they are used in various digital control systems.

The stepper motor selected in this design is a four-phase stepper motor, and the method used is to use a single-chip microcomputer to control the drive of the stepper motor. A stepper motor is an actuator that converts electrical pulses into angular displacement. When the stepper driver receives a pulse signal, it drives the stepper motor to rotate a fixed angle (called the "step angle") in the set direction, and its rotation runs step by step at a fixed angle. The angular displacement can be controlled by controlling the number of pulses to achieve the purpose of accurate positioning; at the same time, the speed and acceleration of the motor rotation can be controlled by controlling the pulse frequency to achieve the purpose of speed regulation. This graduation project adjusts the speed of the stepper motor by changing the pulse frequency, and displays its speed level through a digital tube. In addition, the forward and reverse rotation is realized by a single-chip microcomputer. The stepper motor can be used as a special motor for control. It is widely used in various open-loop controls by taking advantage of its characteristic of no accumulated error (accuracy of 100%).

The system designed in this paper has the advantages of easy operation, flexible control, clear display, low production cost and high cost performance.

hardware design

The hardware circuit consists of the following modules:

(1) Single-chip microcomputer minimum system. It is used to drive and control other modules to achieve the overall function. It uses the STC89C52 single-chip microcomputer as the core chip, supplemented by a reset circuit and a crystal oscillator circuit.

(2) Button module: Use buttons to control the forward, reverse, acceleration, deceleration, and stop of the stepper motor.

(3) Display module: A 7-segment LED digital tube displays the current speed gear (9 gears in total).

(4) Stepper motor module.

(5) Speed ​​indication module and forward and reverse indication module.

software design

According to the design requirements of this article, on the basis of hardware circuit design, the specific functions that need to be implemented through software programming are:

(1) Drive each module to work, realize clear display of digital tube, and realize motor drive;

(2) Realize key control of stepper motor forward, reverse, acceleration, deceleration and stop;

(3) Two LEDs display forward and reverse rotation, and a 7-segment LED digital tube displays the current speed gear (9 gears in total);

(4) 4 red LEDs, indicating the motor speed.

Schematic

The schematic diagram of this system was designed using Altium Designer19, as shown in the figure.

program

This design uses KEIL5 software to implement program design, as shown in the figure.

Simulation Implementation

This design uses protues8.7 software to implement simulation design, as shown in the figure.