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An Autonomous Four Wheeled Robot

Sangeetha ThomasEC Engineering Department

Parul Institute of Engineering & Technology

Vadodara ,INDIA

[email protected]

Asst Prof.Anuradha P. Gharge,EC Engineering Department

Parul Institute of Engineering & Technology

Vadodara ,INDIA

[email protected]

Abstract Mobile robots are becoming a common sightnowadays. There are two major types of mobile robots the

wheeled and the legged mobile robots. Wheeled robots are more

common as they are easier to design and build. The cost of

building a wheeled robot is generally low. The wheeled robots are

more suited to application on fairly even terrains than traversing

on uneven or rough terrains. Legged robots, on the other hand,

are less common, although the interests in them have been

growing at a frantic pace over the past few years. Legged robots

are more difficult to design and built as compared to the wheeled

robot. This is due to the complexity in designing the actuators

and joints... The cost of building a legged robot is also generally

quite high. In this application we have selected a wheeled robotwhich has four wheels for movement. This paper discusses about

the design of a wheeled robot that can be built at a minimum cost

but at the same time without affecting the robots capability. The

robot is capable of moving forward, backward, it can turn left

and turn right.

Keywords-wheeled robot, legged robot, actuators

I. INTRODUCTION

Robots are programmable physical machines that have sensors

and actuators, and are given goals for what they should

achieve in the world. Perception algorithms process the sensorinputs, a control program decides how the robot should behave

given its goals and current circumstances, and commands are

sent to the motors to make the robot act in the world. Some

robots are mobile, but others are rooted to a fixed location.

A robot is a machine that imitates the actions or appearance

of an intelligent creature- usually a human & gathers

information about its environment (senses) and uses that

information (thinks) to follow instructions to do work (acts).

Thus to qualify as a robot, a machine has to be able to do two

things:

1) Get information from its surroundings

2) Do something physicalsuch as move or manipulateobjects.

Almost all robots are comprised of a movable body, wheels

operated by motors, and parts which can be moved made of

plastic or metal. The sections are coupled together with joints.

Solenoids and electric motors are used as actuators to operate

the robots, while hydraulic and pneumatic systems are alsoutilized for this purpose. Although the appearance and

capabilities of robots vary, all robots share the features of a

mechanical, movable structure under some form of

autonomous control.Autonomous robots are robots that can perform desired tasks

in unstructured environments without continuous human

guidance. A high degree of autonomy is particularly desirable

in fields such as space exploration, cleaning floors, mowing

lawns, and waste water treatment. A fully autonomous robothas the ability to

Gain information about the environment.

Work for an extended period without human

intervention.

Move either all or part of itself throughout its

operating environment without human assistance.

Avoid situations that are harmful to people, property,

or itself.

II . AUTONOMOUS ROBOTS

Autonomous robots are self supporting or in other words

self contained. In a way they rely on their own brains.

Autonomous robots run a program that gives them the

opportunity to decide on the action to perform depending on

their surroundings. They start out with a short routine and

adapt this routine to be more successful at the task they

perform. The most successful routine will be repeated as

such their behavior is shaped. Autonomous robots can learn

to walk or avoid obstacles they find in their way. Think

about a six legged robot, at first the legs move at random,

after a little while the robot adjusts its program and performs

a pattern which enables it to move in a direction. Any

Autonomous Robot consists of following essential parts:

1. Robot Chassis and actuatorsIncludes wheeled or any type of chassis with all the necessary

actuators fitted on the chassis to achieve desired goal. We

mostly use DC geared motors as actuators.

13-14 May 2011 B.V.M. Engineering College, V.V.Nagar,Gujarat,India

National Conference on Recent Trends in Engineering & Technology

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2. Electronics

Electronics includes Sensors, motion control circuits, power

management system etc.

3. Power Source

Usually battery pack consisting of Lead acid, Nickel

cadmium, and Nickel metal hydride or Lithium batteries is

used.

4. IntelligenceThis is the most important part of the autonomous robots.

Usually intelligence is achieved by using Microcontroller.

In this application we have selected an autonomous wheeled

robot which has four wheels for movement.

III. PRELIMINARY DESIGN

The proposed robot for this project uses four motors as the

actuators. In the design the proposed robot will use two motor

each to control the front and rear legs. In addition to that,

micro controller and sensors will be added to improve the

robots capability.

The Robotic Unit is programmed to operate in three modes.

They are: 1) Manual Mode or Remote Control operation

mode. 2) Wall Following Mode (Left Wall) and 3) Fixed

Mode (Path loaded through PC).

The controller which consists of an Atmega 16

microcontroller and appropriate electronic circuitry will be

feed with input from sensors (analog distance sensor, metal

detector sensor and smoke detector) and drive the four motors.

Finally, this project is focusing on the programming aspect to

control the robots movement. The suitable program

arrangement needs to be programmed to ensure smooth

movement of the robot and able to respond sensitively to the

sensor. The autonomous robot, will be able to send the

environmental status, the temperature condition, and if there is

any obstacle on its path, and what is the obstacle in any remote

place which is not reachable by the humans and this will be

displayed on the LCD screen.This project can be divided into

two parts, i.e. Robot end and user interface (Control) end.

Robot is monitored and controlled from remote place.

Robot has an array of sensors for monitoring environmental

status. Since it started to move, it will check whether there is

any obstacle in its path and if there is any obstacle it will

detect the obstacle material, and the current environmental

condition of the place where the robot is situated and also the

gripping force of the robot by means of PIR sensor. From theuser end we will get the data acquisition of monitoring

parameters at the robotic end and the system will

automatically store the database of data acquired from other

end at frequent interval of time (in seconds). Robots

movements (Forward, Reverse, Left, and Right) will be

controlled via wireless medium. Zigbee-based Robot

Localization and Control project uses wireless nodes to

simultaneously localize and control the robot.

The proposed robot consists of five major subsystems They

are the mechanical structure, controller and software, drive

system, sensory system and power supply system.

Mechanical structure

The mechanical structure is the whole chassis of the robot.The structure will form the base where all the components

such as the motor, controller, sensors, and batteries are

mounted. Some of the important features that the mechanical

structure must possess are:

Rigid and stiff

Lightweight

Non-corrosive

Durable.

Controller and software

The controller will act as the brain of the robot. It will control

the movement of the robot based on the preloaded program aswell as the feedback from the sensors. The following are some

of the important features the have been identified for the

controller:

Fast

Sufficient number of input and output ports

Low power consumption

Ease of programming

Availability

The software used in this application is AVR Studio where

program is written in C language and Proteus software is used

for the virtual simulation. The results for speed control of

motor using Proteus Software is shown in the Results

Section.

Drive system

The drive system will be the motor which will serve to move

the robot. Among the important features that must be taken

into account when choosing the drive system is:

Torque

Weight

Ease of control

Sensory system

The sensory system will be the eyes of the robot. It will help

monitor the surroundings of the robot and feedback importantinformation to the robot regarding its surroundings. With the



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information, the robot will then decide on its movements. The

sensors have to be:

Accurate

Reliable and consistent

Fast

In this application we will be using Wall detection sensor,

Metal Detector sensor and Smoke sensor.

Power supply system

The power supply will provide the robot the necessary energy

to function. Since the robot is autonomous, portable power

supply is needed. Among the important parameters that are

important in choosing the power supply are:

Power storage capacity

Weight

Cost

Size

Here, we are using a Solar Panel of 10 watt to store the solar

energy which will provide charge to the Lead Acid batteryused. Hence the name is Solar Based Autonomous Robot.

IV. HARDWARE OF THE ROBOTIC PLATFORM AND

REMOTE CONTROL PART:

Figure.1. Robotic Platform

Figure.2. Remote Control Unit

V. ROBOTS ABILITIES

Once the robot characteristics have been identified, the next

step is the analysis for identification of strengths and

weakness. The robot is tested by moving it on flat surface and

grass surface. From experiments conducted, robot was able to

move perfectly on flat surface. However, difficulties occurred

when the robot tried to move on grassed surface. The robot

was still able to move, but the direction will be somewhatmisaligned.

The sensitivities of the robot

The final process in the analysis stage is to test the alertness of

the robot. In testing the alertness of the robot, the alertness of

the sensor is tested earlier. It is found that the sensor was able

to detect obstacle ahead in distance of 3cm and above in clear

lightning. Therefore, for every analysis the maximum and

minimum of alertness needs to be co-ordinated before the

testing take place. Next the robot was activated and freely

moved forward without controls. It is found that the robot was

able to respond to obstacles in front. When the right sensor

detected obstacles on the right, it turned to left direction andvice versa.



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VI. RESULTS OF SIMULATION IN PROTEUS, AND

VISUAL BASIC.

In Figure-3, the output window in Proteus shows that the

Speed of DC Motor is decremented and it gets displayed on

the LCD screen too. In Figure-4, the speed of DC Motor is

incremented and it is displayed on the LCD screen. Figures 6

to 8 show the output in Visual Basic 6.0.

VII. CONCLUSION AND RECOMMENDATION

This paper discusses about the development of a four wheeled

robot actuated by four motors. This is implemented using

Atmega-16 microcontroller which was programmed using the

C programming language to control the robot. The robot was

successfully built and tested as specified by the objective.

Through the development of the project, many skills have

been acquired. The skills are circuit design and interfacing

hardware and software in computer. It should be noted that the

project is carried out with limited resources and funding.

Therefore, this robot is not appropriate to be marketed or

commercialized. Although a four wheeled robot was

successfully developed which met the objectives, however it is

found that this robot still can be improved by implementingsome modifications. For future work, the mechanical structure

can be improved by building it with more joints and motors

for mobility which would be suitable at any terrain. More

sensors can be placed at the rear and sides of the robot for

more alertness.

Figure 3. Result of simulation in Proteus (Motor speed getsdecremented)

Figure 4. Result of simulation in Proteus (Motor speed gets

incremented)

Figure 5. Code window in VB



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Figure 6. Object window in Visual Basic after simulation.

Figure 7. Fixed mode output in Visual Basic.

Figure 8. Wall Following & Remote Control Mode output.

REFERENCES

[1] A Six Wheeled Solar Robot by MOHAMED SAIFUL B ZAINAL

ABIDIN.

[2] A Review on Robotics by Rodney Brooks, MIT, Version 4: March 17,2009.

[3] The Current State of Robotics: Post or Pre-Robotics? By Miguel A.

Salichs, Carlos Balaguer, Robotics Lab, University Carlos III. Email id:{salichs, balaguer}@ing.uc3m.es.

[4] History and Development of Robots by Christopher Haggis, Wagner

College, May 2003.[5] FREGO Bot: Fully Rectangular Excellent Great Outstanding Bot, Fully

autonomous exploration robot by Dave Ceddia, Mike Howlett, Jim

Censabella, Robot Design Lab Olsen Hall Room 306, UML Computer

Science Department, Lowell MA, 01854.

[6]Robotics: The Past, the Present and the Future By Shuzhi Sam GE,

Director, Social Robotics Lab, Interactive Digital Media Institute, &Department of Electrical and Computer Engineering, National University of

Singapore E-mail: [email protected].[7] An Autonomous Four-Legged Robot' by AHMAD SAIFUDIN BIN

ISKANDAR, Universiti Teknologi Malaysia, MAY 2010.



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