PC-Based Mobile Robot for Naviga-

tion

Ankit Surti325

Introduction… The navigation system plays very an important role and challenging compe-

tence for mobile robot.Navigation of mobile robot includes a variety of theo-ries and technologies such odometry technique, ultrasonic mapping, and vision system.

In the application of navigation, it consists of two areas: global navigation and local navigation.

Global navigation such as GPS (Global Positioning System) and INS (inertial Navigation System) is often used in various open areas. Meanwhile, local navi-gation such as vision techniques are very effective base in the closed range navigation.

Navigation using vision approach has many tasks, including target matching, target identification and others. Practically, the use of optical sensors and image processing are the major factors affecting the accuracy of navigation.

In navigation application, a mobile robot must interpret its sensors data to ex-tract environment information, with which the mobile robot can determine its position.

After mobile robot can localize its position, it must decide how to act to achieve its purpose. Lastly, the mobile robot must control its drive system to achieve the desired path. The increment distance of the robot’s movement sensed with wheel encoders is integrated to calculate position.

Context…

Working prototype of the PC-based mobile robot

1.Vision Sensing This work presents an approach using computer vision which applied feature matching technique after the image has been proceeds by Canny edge detector. Features like circular marking, the distance be-tweentwo vertical lines used by the fuzzy system to analyze whether it has relation with the door being analyzed to design anexpert system to detect rectangular shaped door. In this study, vision system is ap-plied to extract the information such as the dis-tance of target and the orientation of target.

Circuit Diagram…

Interface-cum-driver circuit for the PC-based mobile robot Power supply circuit

2.Mobile Robot Control System The posture provides information about how the mobile robot moves with respect to the floor Fuzzy Logic Controller:The master controller is a fuzzy logic controller (FLC) which computes the required speed and angular speed needed by the two motors to drives the robot for target trajectory. Obstacle Avoidance Algorithm:Our obstacle avoidance algorithm uses the principle of appearance-based obstacle detection. According to this principle,any pixel that differs in appearance from the ground is classified as an obstacle.This method is based on three assumptions that are reasonable for a variety of indoor andoutdoor environments: 1. Obstacles differ in appearance from the ground. 2. The ground is relatively at. 3. There are no overhanging obstacles.3.Power SystemThe vehicle electronics, including the onboard computer and the drive mo-tors, are powered by an uninterrupted power supply (UPS) running on a 12V dry battery. On a full charge,the battery can keep the robot running for approximately 30minutes. An AC/DC converter is used to provide 9V input tothe drive mo-tors. As the UPS comes with a surge protection Socket.

PCB Bottom View

Top View

The Software for ControlsThe software program for the user interface to control the ro-bot (Mobilerobot.exe) is designed in Visual Basic6.0. The core file used by software is ‘inpout32.dll,’ which can be downloaded from ‘www.logix4u.net’ for free.The .dll file uses a kernel-mode driver.Therefore this software works as good with NT-based Windows OS as withWinXP and Win2000.A separate program module for the inpout32.dll isused alongwith the main program of the mobile robot. For details about the .dll file, visit‘www.logix4u.net’.The software uses timercontrols to produce delay in betweenthe counting sequence that controls the speed of the stepper motors.

Component List1.Semiconductors:IC1-IC8 - MCT2E opto-couplerIC9 - ULN2803 buffer/driverIC10 - 7812 12V regulatorD1-D4 - 1N4001 rectifier diodeLED1 - 5mm light-emitting diode

2.Resistors (all ¼-watt, ±5% carbon):R1 - 1-kilo-ohmR2-R9 - 470-ohm

3.Capacitors:C1 - 1000μF, 35V electrolyticC2 - 0.1μF ceramic

4.Miscellaneous:X1 - 230V AC primary to 15V,1A secondary transformerCON1 - 25-pin, D-type, parallel-portmale connectorSM1, SM2 - 12V, 7.5deg/step steppermotor- 8-conductor ribbon cable(3.5 metres in length)- Two wheels for right andleft side of the robot- One castor wheel for front- Two side brackets forstepper motor support- One chassis board- One webcam or PC camerawith USB interface cable- Nuts and bolts- 2-pin SIP connector (maleand female)- Two 5-pin SIP male connector- DC socket and plug

Working… MCT2E is the most popular integrated circuit used for isolating high-voltage

circuits from low-voltage circuits. Used to protect the parallel port from damage, it is an opto-coupler having an internal photo transistor and an LED.

The LED glows when it receives high output pulse from the parallel port. The transistor conducts when its base receives light from the lated 12V DC is connected to ULN2803 driver IC. In place of the power supply circuit shown in Fig. you can also use a 12V, 4.5Ah battery to power the main cir-cuit.

Two stepper motor are used for moving and turning the robot.Each of these stepper motors has five wires for connecting to the driver circuit. Out of the five wires,four wires emerge from coils of the stepper motors and the fifth is the centre-tapped common terminal.Correct identification and connection of these wires is important for successful assembly of the stepper motor.

The unipolar stepper motor has two centre-tapped coils.Their centre tapped terminal are joined to make one common terminal. Connect these coils to the output terminals of the driver circuit in sequence.

Then the Robot work on 3 main factors: 1.Direction Control 2.Speed Control 3.Camera View

Advantages Ours is a Wireless ROBOT with Wireless Movements. Ours is an industrial ROBOT, Controlled by the PC . It is also a Mobile Robot which has got certain artificial intelligence

feature . Our ROBOT will pick the Objects and will place it in another place. Another unique concept about our ROBOT is that it can serve any

fire and detect the fire. Consistency of performance. 240 continuous working. Reduced cycle times. Reduced amount of operator errors. Improved quality of product.

Disadvantages High standard of maintenance required Precise programming needed (time, training, specialist knowledge) when computer systems failure will cause break-

down New products require complete reprogramming Certain processes still need a skilled operator Complex and expensive equipment to buy and in-

stall

Conclusion… Landmark recognition is not an easy task but it is very important

area in developing mobile robots that is need to accomplish posi-tioning, path planning and navigation.

A robot vision system using fuzzy logic technique to identify the ob-ject in real time was presented. The system is able to find and recognize the circle and then calculate the position of the robot to navigate in a laboratory.

The technique used is based on image processing and optimization in real time. It hard to an able a mobile robot navigates in indoor environment.

The output is very useful for a mobile robot in real time to find and detect objects. Usually a robot vision system is very slow due to computational time used for image processing. Image processing time was minimized by the techniques used and the detection of ob-ject can be done about less than 1 second.

Conclusion…An analysis and design of fuzzy control law for steering control of the developed non-holonomic mobile robot are presented. The proposed fuzzy controller is implemented on the developed mobile robot.The system can perform and satisfactory results are ob-tained which show that the proposed fuzzy controller can achieve the desired turn angle thus it can make the autonomous mobile robot moving to the target. The control system need PID controller to guarantee the stability of the straight conveying and turning trajectory.