UVU Electrical Engineering Capstone Project

Efficient DC Motor Control System

Team Members: Tu Phan and Robert Turner

Faulty Advisor: Dr. Afsaneh Minaie

Poster for Motor Control System

Motors can be found at almost every place, and motor control is essential in many aspects of life. Particularly, motor control is a complex process involving many complicated concepts and the relations between them, and thus, is a good practice for us to devote time and effort to. The purpose of this project is to design a DC motor control system that meets desired specifications, but its price is much lower than an equivalent servo motor that can be bought off the shelf. The motor must be able to rotate 360 degrees in three seconds while stopping and starting every 100 milliseconds.

The complete system includes three major components: a DC motor, an encoder, and a microcontroller. After the DC motor has started working, the encoder determines the position of the motor so as to produce digital signals that will be sent to the microcontroller; the microcontroller then changes the motor’s direction and speed to the desired values by a built-in pulse width modulation (PWM) and an H-bridge circuit. The microcontroller needs to be programmed so it can read the signal from the encoder and output a PWM signal to the H-bridge. In addition, a shaft coupling is needed for transferring rotation of the motor to the encoder, and thus, a holder is designed to hold the motor and the encoder in their places. Some other components are used such as: amplifiers to buffer the signals coming from the encoder and eliminate high frequency signals for analog-to-digital (ADC) conversion in the microcontroller, a communication module to provide an interface for communication between the microcontroller and the computer, a voltage regulator to provide power supply to some IC chips that require a supply voltage of less than 12-V.

Research on all the components of the system as well as how to get them to work together was done. After that, most parts needed for the project were chosen and purchased. From here, a schematic was designed, and then all components were put together as a completed system and implemented. The system successfully met most of the specifications: under the control of the microcontroller, the motor can start and stop after every 100 milliseconds or it can complete a full rotation in three seconds. Unfortunately, it can’t complete both specifications at the same time due to the potentiometer not giving consistent values. While an available system costs about 500 dollars, the designed system was manufactured at a little over 100 dollars. The cost saved is almost 400 dollars per unit!

Students' Presentation