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An Autonomous Four Wheeled Robot
Sangeetha ThomasEC Engineering Department
Parul Institute of Engineering & Technology
Vadodara ,INDIA
Asst Prof.Anuradha P. Gharge,EC Engineering Department
Parul Institute of Engineering & Technology
Vadodara ,INDIA
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.
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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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