DC Motor Speed Regulation with A PWM Feed Back System

March 24th, 2008 by Robot Technology | No Comments | Filed in Mechanics, Microcontroller, Programming, Robotics Tutorial

This tutorial will helps you how the PWM works. You will learn what is PWM, the usage of PWM also how to program a DC Motor with PWM. Some Robots need to control the motor speed for its to work. Just use PWM system and you will get your motor’s speed adjustable…

Basic PWM

One of the easiest ways of generating an analog voltage from a digital value is by pulse-width modulation ( PWM ). I PWM a high frequency square wave is generated as a digital output. For example, a port bit continuously swiched on and off at a reltive high frequency. The signal is fed to a low pass filter. The voltage at the otuput of filter is equal to ther Roo Mean Squeare ( RMS ) of the squeare wave signal. The RMS of the square wave signal may then be varied by changing the duty cycle of the signal. A cycle is initiated by a low to high transition of the signal and terminates at the next such transition. During one cycle if the time the signal stays high is equal to the time the signal stays low, then the duty cycle is said to be 50 percent.

Figure 1. Duty Cycle 30 %

The following circuit shows a DAC constructed with PWM. The Program controls the speed of a DC motor by pulse width modulation ( PWM ). Bit P3.0 Drives a switching transistor as shown in the circuit diagram. Motor is swiched on for a period of time, and then off. The fraction of time the motor is on is call the duty cycle.

Continue reading DC Motor Speed Regulation with A PWM Feed Back System ...

Tags: , , , , ,

4 Legs Walking Robot Tutorial

March 23rd, 2008 by Robot Technology | 9 Comments | Filed in Electronics, Mechanics, Microcontroller, Programming, Robotics Tutorial, Sensors

4 Legs walking Robot

Another robot project you can find here:

======================================

Introduction
Once I made this robot to get some study points while I was studying at the Technical High school in Rijswijk, the Netherlands. I made this in my limited free time, that is why it took me about a year to finish the project. A lot of the used techniques where new, so the research took a lot of the time, but is also the reason why this project had great value to me.

Target
Before I started developing the robot I made a few targets:

Continue reading 4 Legs Walking Robot Tutorial ...

Tags: , , , , , ,

Driving Stepper Motor

March 22nd, 2008 by Robot Technology | No Comments | Filed in Electronics, Mechanics, Microcontroller, Programming, Robotics Tutorial

Stepper motor is very useful for some robots to make their high accuracy movement. How to drive or control your stepper motor? Use this tutorial as your guide….

General Theory of Stepper Motors
An ordinary DC motor will turn around and around as long as power is supplied. No intelligent circuitry is required to drive such a motor, unless you want to slow it down or reverse direction – just apply power and it spins. A stepper motor is very different. If you just feed it power, it will stay where it is. In order to make the motor move, you have to feed it a changing signal. This is best illustrated by thinking of a magnetic compass with electromagnets around it:

Motor Stepper
Figure 2.7.1 Motor Stepper

The drawing on the bottom shows power applied to the N electromagnet, drawing the compass toward it. On the right, power is instead applied to the E electromagnet, and the needle has rotated toward that side.

motor stepper control
Figure 2.7.2. Basic Stepper Motor

Just four electromagnets would give coarse jumpy motion. Now

Continue reading Driving Stepper Motor ...

Tags: , , ,

Line Follower Robot Tutorial

March 20th, 2008 by Robot Technology | 79 Comments | Filed in Electronics, Mechanics, Microcontroller, Programming, Robotics Tutorial, Sensors, Software

Line Follower ROBOT

Plermjai Inchuay, plermjai@loxinfo.co.th

Award winner from VingPeaw Competition 2543, the robot built with 2051, L293D, and four IR sensors. Simple circuit and platform, quick tracking and easy-understand program using C language.

Line Follower Robot design

I designed my robot, which use two motors control rear wheels and the single front wheel is free. It has 4-infrared sensors on the bottom for detect black tracking tape, when the sensors detected black color, output of comparator, LM324 is low logic and the other the output is high. Microcontroller AT89C2051 and H-Bridge driver L293D were used to control direction and speed of motor.

line follower robot circuit

Continue reading Line Follower Robot Tutorial ...

Tags: , , , , , , , , , , , , ,

The Difference Between Stepper Motors, Servos, and RC Servos

March 20th, 2008 by Robot Technology | 1 Comment | Filed in Electronics, Mechanics, Robotics Tutorial

robotics motors

Stepper motors:
A stepper motor’s shaft has permanet magnets attached to it. Around the body of the motor is a series of coils that create a magnetic field that interacts with the permanet magnets. When these coils are turned on and off the magnetic field causes the rotor to move. As the coils are turned on and off in sequence the motor will rotate forward or reverse. This sequence is called the phase pattern and there are several types of patterns that will cause the motor to turn. Common types are full-double phase, full-single phase, and half step. To make a stepper motor rotate, you must constantly turn on and off the coils. If you simply energize one coil the motor will just jump to that position and stay there resisting change. This energized coil pulls full current even though the motor is not turning. The stepper motor will generate a lot of heat at standstill. The ability to stay put at one position rigidly is often an advantage of stepper motors. The torque at standstill is called the holding torque.

Continue reading The Difference Between Stepper Motors, Servos, and RC Servos ...

Tags: , , , , , , ,

Page 3 of 41234