CHAPTER ONE

INTRODUCTION

1.1 Background to the Study

A robot is seen as a machine of the modern day with improved technological advancements and robotics is one of the subfields of mechatronics. It is a considered to be a mechanical/virtual artificial agent, usually a goal driven machine, an electro-mechanical machine that is being run based on series of computer programs or electronic circuitry. A robot based on the concept of medicine which is having the ability to reason and also have a sense of intelligence by mimicking an automating movement. There are different categories and types of robots. Examples are: The wheeled robot, crawling robot and legged robot etc. The Robot combines four independent subsystems to accomplish this task: navigation, vision, program and wireless control, all of which are mounted on a mobile platform. All of these subsystems are interfaced through a microcontroller.

Various advances have been made in the world of technology and robotics, a few of those advancements have been observed in artificial intelligence, security in general and so on but the concern here deals with an obstacle avoidance vehicle that incorporates knowledge from computer science, robotics, system analysis, algorithm, and electro mechanics, mechatronics, software development, engineering and programming an autonomous robot. This study major on the ability of the vehicle to detect and move past obstacles using components that enable these functions.

Electronics have found their place into the development and the initiation of the first electronic autonomous robots produced in Bristol England by William Grey Walter in the year 1984, also the first digital and programmable robot was invented and named Unimate in the year 1954 by George Devol. Sumit Garethiya  in is dissertation “the first ever system to detect an obstacle was developed by Delco System operations, Goleta of California in 1988”. The study was mainly a safe way to spots obstacles on road then inform the motorist.

In the world today, robotics is a fast growing innovation. With the evolving of different technology in various fields of science, human life has become more convenient and relaxed with the advancement of technology that brought about a robot.. Robotics are used in places that are dangerous for human to reach directly, these robots are used in those places by gathering information from the environment to avoid obstacle. Robot are used in factory/industry to prevent workers from being hurt.

           Nowadays many industries e.g (legos robotic) are making use robots because of the level of efficiency, performance and dependability which is of great help to human life. The design of obstacle avoidance robotic car need the integration of many components like the ultrasonic sensor, microcontroller, diodes, motor drivers IC, DC Motors etc according to their task.

This study proposes an autonomous robotic car that has the ability to control its direction when an obstacle comes in its path. This car is constructed with a micro controller of (PIC16F84A family). An ultrasonic sensor is used to sense any obstacle ahead of the robotic car and forward the signal to the microcontroller. The input signal received would determine, the way the microcontroller interpret it and control the robot to move in an alternative direction by triggering the motors which are done through a motor driver.

The main task of the car is to go in a straight direction and whenever the obstacle car senses an obstacle in its way, and this is done with the use of an ultrasonic sensor and dodge the obstacle and then continue in its own path. Obstacle detection is the primarily obligation of this self-driven robot. The robot gets it information from is immediate environment with the help of the sensor fixed robot, there are various sensing devices like, infrared sensor, ultrasonic sensor, cameras etc. We would be making use of ultrasonic sensor for this project and it would be attached in front of the robot and multi vibrator, which is fixed at its base. Ultrasonic sensor is more appropriate for obstacle detection because of its high ranging capability. The Ultrasonic sensor is made up of two parts which are the emitter and the detector. The emitter which produces 40KHz sound wave and detector which detects 40KHz sound wave and emits frequency signals, when obstacle is detected this signals are reflected back which is considered as input to the microcontroller. The microcontroller controls in different direction either left, right or front based on the signal received from the ultrasonic sensor.

The study is to design a robotic car that will move in accordance to the code programmed on it, it would move in a straight direction and if it senses any obstacle in its way it would check for a free space and avoid the obstacle. The obstacle avoidance robot would be useful in the various places like the industrial area where less supervision is need and prevent the risk of human been getting hurt in the process of working.

1.2 Problem Statement

In the past, the rate of accidents on a typical Nigeria road has increased as many year passes by and it is still rising. The major cause of these accident cases is as a result of lack of awareness of obstacles (bumps), whether it is a coming vehicle or a pedestrian or even a domestic animal on the road and in some cases brake failure.

The study is an attempt towards developing a robotic car that would be able to detect and avoid obstacle (bumps) in the robot’s path using a sensor to achieve the target point in an optimized manner. With the use of an obstacle avoidance technology in the car, it will automatically alert the driver (or even the car itself) of the obstacle ahead with a possible means of avoiding the obstacle depending on the advancement of the technology, thus, effectively reducing the rate of mortality on the road.

When the robot gets to an environment that it is not use to, it will stop scan through it environment, thereby processed it to recognize any obstacle. With the use of state of art of necessary equipment, the robot can avoid obstacle and finds a secured path thereby causing reduction in accidents and non-avoidance of obstacles. Once the robotic car performs a task, it will store the task which will then make it perform better when another task is given which would be based on the updated percept (a combination on the current percept with the information that exist in it knowledge base with an internal state).

1.2    Aim and Objective of the Study

The aim of this project is to design an obstacle avoidance robotic car with enough effective means to be implemented in the modern model vehicles of today.

The specific objectives of this project are:

1.      To evaluate literature related to the fields of engineering, mechatronics, and software development in the design, construction, and programming of an autonomous robot.

2.      To design a robotic car capable of obstacle detection in a controlled environment.

3.      To interface the robot with a real-time system that will enables it perform assigned tasks.

4.      To achieve optimal performance from the robot and distinct quality in contrast to other obstacle avoidance robot’s known

1.3             Methodology

1.      To evaluate literature related to the fields of engineering, mechatronics, and software development in the course of designing, construction, and programming and autonomous robot. A lot of related works have been made on the study of engineering, mechatronics and software development in the designing of a robotic car. With exposure to similar studies about obstacle avoidance, different areas of computer science have been discussed, from software development to the assembling of various components required to accomplish the project work using a well-structured circuit design. We were able to have a good knowledge and idea of the study and develop a suitable methodology             for the project.

2.      To achieve the objective of detecting obstacles in an environment the following has to be ensured;

a)      Obstacle Sensing Unit: consists primarily of the ultrasonic sensor using HR-SC04 Model.

b)      Angle Scanning Unit: consists of the servomotor with a hanger connected to the sensor. It is a rotary motor that provides linear and angular positioning of the sensor.

3.      For the robot to perform task using the real time system the following are required:

a)      Comparator Unit: operates by comparing the sensor voltage with a reference voltage where the output voltage is sent to the microcontroller which is the decision making device for the robot.

b)      Signal Processing Unit: is made of the microcontroller that is pre-installed with a function software which aids with the decision making of the robot. Using the PIC16F84A microcontroller equipped with a flash memory for quick signal response and 68byte RAM of user storage space.

c)      Motor Drive Unit: from the signal sent from the microcontroller the motor drivers act out the decisions made, to turn left or right, to go slow or fast.

d)      And lastly a Power Supply Unit is needed to power the whole system with 9v power supply.

4.      To achieve optimal performance from the robot and distinct quality in contrast to other obstacle avoidance robot’s known.

Our project work has been done by so many other people across the world using different ways and approaches to develop an autonomous robotic car. We were able to distinct our own robotic car from the previous work done by the other researcher by designing an autonomous robotic car with a free wheel in front of it, that controls the other two wheels behind it.The robot has the ability to move in a straight part by scanning both left and right and choose the direction that is free for its to move and if both sides are blocked its reverse back and stop for another scan for a free space. 

1.4             Significance of Study

Obstacle avoidance is very useful in real life. The robotic car is  to detect an obstacle that comes its way. Obstacles include chairs, desks, bottles, walls e.tc and correspondingly changes its direction to avoid any collisions according to the pre-existed programme on the microcontroller that can only be performed when it receives a signal from the environment through the sensor mounted in front of the robotic car as the name implies obstacle avoidance robotic car. This robot will be able to produce the basic performance with the use of the code programmed on it so as to sense the obstacle then decode the information coming from the sensor and then perform the right task either by moving forward or scanning through its environment for an obstacle in its way. When the entire system is combined together, the car will achieve a great functionality of avoidance.

1.5             Scope of Study

This research is centred around designing an autonomous obstacle avoidance robot that would be able to sense any obstacle in its paths, with the use of the ultrasonic sensor and then make 90˚or 180 ˚turn to look for a free space to avoid the obstacle and resume its normal direction which is control by the microcontroller. The research work would be limited to obstacle avoidance using robotics.

1.6    Organization of other Chapters

  This project is made up of five chapters as introduced below:

Chapter One: Includes the Introduction, Problem statement, Aims and objectives of the system, Methodology, Significance of study, Scope of study, and Expected outcome.

Chapter Two: Includes the Literature review: To review some of related works already done in this regard.

Chapter Three: Contain the Design and Analysis likewise the component to be used for the project.      

Chapter Four: Contains the circuit design, Model Algorithm codes, Testing and implementation of the design.

Chapter Five: Contains the summary, conclusion, recommendation, limitation and suggestions for future study.