THE EXPERIMENTS AND PERFORMANCE ANALYZES OF THE TRACKER ROBOTS IN DIFFERENT LIGHTING ENVIRONMENTS S.M.Fatih APAYDIN1, Abdullah ÇAVUŞOĞLU2, Lami KAYA2 1 Distance Education Application and Research Center Karabük University fatihapaydin@karabuk.edu.tr 2 Faculty of Engineering and Natural Sciences Yıldırım Beyazıt University abdullah.cavusoglu@ybu.edu.tr, lamikaya@ybu.edu.tr Abstract In this study, a leader robot and tracker robot was studied on two robots. In accordance with the intended target has been tracking the leader robot to tracker robot. Experiments were carried out in terms of performance of different soils and environments to robots and the results of these experiments performed by measuring the necessary improvements. Keywords: Mobile robot, remote and autonomous control, infra-red sensors, arduino. I. INTRODUCTION The robots have a very important place with respect to facilitating our lives, in the age of information and knowledge which the technology have been developing rapidly and this development has been spreading quickly to all strata of society; such that humans request many routine works in their lives being done automatically. The technology forces its limits insomuch that robots in appearance of human were produced by scientists and researchers and even autonomous mobile robot devices that can go to the desired targets by itself have been revealed. Concerning to mobile robot systems’ design; such subjects have been involved like how it represents the information related with the environment around itself, how it learns the tasks to be carried out, what kind of planning and problem solving to be done, how fast it scan the data bank and information in order to reach the answers, which mechanisms it uses in order to recognize the world containing itself [1]. The robotic vehicle of Mercedes Benz, developed by Ernst Dickmans and his team who had been working at University of Bundeswehr in Munich in 1980s, achieved to reach 100 km/s speed in a road without any traffic. Also the DARPA project, which utilizes laser and image processing technologies and moving with 30 km/s speed, has been developed in 1980s. However nowadays General Motors, Volkswagen, Audi, BMW, Volvo, Google have begun the tests of their autonomous vehicles. The General Motors company stated that their autonomous vehicles will start to test in the year of 2015 and these vehicles could be on the roads in the year of 2018. The law regarding to usage of autonomous vehicles at traffic, also with the largest support of the Google, has been created as being first in the world in State of Nevada of the U.S. in June 2011 [2]. The autonomous vehicle of Google is seen on the Figure 1. Fig 1: Autonomous Vehicle Of Google Also the vehicle systems which follow each other referred as Platoon is one of the subjects that has being studied over it recently. The platoon systems are increasing of the usage capacities of the roads by moving as grouping the vehicles. The platoon systems are a technology being recommended for Automatic Highway Systems [3]. The platoon systems aim to shorten follow-up distance between the vehicles by utilizing electronic and mechanic parts. Additionally the vehicles speed up and slow down simultaneously [4]. The California PATH Platoon sample was given in Figure 2. Fig 4: Mobile Robot System III. Fig 2: The California PATH Platoon However some studies upon Platoon systems known as SARTRE (Safe Road Trains for the Environment) have been carried out in the Europe. In scope of the project supported by European Commission and Volvo too, it has been aimed to develop a secure and environmentally friendly new driving system by creating Road Trains [5]. SARTRE Platoon sample was given in Figure 3. APPLICATION In this chapter, mechanical designs of autonomous moving mobile robots as well being the subject of this study too together with electronic circuits and software used in order to control the robots are described. The study is basically divided into two areas in line with two different targets. Therefore two different robots have been studied over. The first one of them is the robot referred as “Pioneer” that can be remote-controlled and determines the path. The other one is the “Follower” robot which follows the pioneer robot. 3.1. Pioneer Robot 3.1.1. character of the robot The pioneer robot is able to operate in two different modes. For the first mode, it has an attribution that can be remote-controlled and able to move freely. The other mode is programmed as able to move completely autonomous. General character of the robot is to determine the path to be followed by planning the way. Fig 3: The SARTRE Platoon II. MOBILE ROBOTS Mobile robots are the vehicles which are equipped with motion systems for the purpose of able to move inside of physical environments and able to affect the environment and equipped with sensor systems for the purpose of able to perceive the environment being inside; have control architecture that carries out the coordination and control of these systems upon performing tasks requested from them [6]. The components of mobile robot systems are described in various sources with different point of views [1, 7]. General display of mobile robot system was given in Figure 4. 3.1.2. mechanical part The wheels of the robot were positioned as to move on five wheels on condition that two wheels at sides, one ball-bearing wheel at front. The wheels at right and left have geared motor system. It was created by mounting two DC motor and other components on a rectangular plexiglass material. The view from the bottom of mechanic assembly of the pioneer robot was given in the Figure 5 below. Fig 5: The Bottom Of Mechanic Assembly Of The Pioneer Robot 3.1.3. electronic part The pioneer robot has a form that will operate with PIC. Electronic circuits of the robot consist of three parts. These are; microcontroller and motor driver circuit, line follow circuit and infra-red sensor circuit. Microcontroller and Motor Driver Circuit Many models are available for PIC microcontrollers. However 16F877A model which is being widely used and most developed has been preferred for the pioneer robot. Also the L293D has been used as a motor driver. Line Follow Circuit Three CNY70 contrast sensors and Schmitt Trigger trigger have been used in line follow circuit. 3.2. Follower Robot 3.2.1. character of the robot The follower robot operates in an easily manner due to required to be easy and fast. The general character of the robot is to follow the front robot. 3.2.2. mechanical part The follower robot has a form that move on three wheels and these were positioned as being one wheel at each sides, one ball-bearing wheel at rear. The robot was created by mounting two motors and other components on a rectangular electronic card. The view from the bottom of mechanic assembly of the follower robot was given in the Figure 7. Infra-red Sensor Circuits There are TK19 infra-red receiver-transmitter sensors on the pioneer robot. These are totally five as being two of them at front, two of them at left and one at right. 3.1.4. Algorithm and Software The software of the pioneer robot was written in Jal programming language. The Jal is a pascal-like and free PIC programming language. Totally 11 procedures were used in the pioneer robot. These may be called as small code blocks inside of the software. The algorithm of the pioneer robot can be viewed in Figure 6. Fig 7: The Bottom Of Mechanic Assembly Of The Follower Robot 3.2.3. electronic part Electronic circuits of the robot consist of two parts: arduiono card and sensor circuit. The follower robot was designed as to operate with ATMEL. ATmega8A model of ATMEL microcontroller was used in this robot. Arduino Circuit Arduino card is an electronic card especially used in many robot projects abroad and developed with ATMEL microcontroller architecture. It can easily develop very sophisticated robotic projects thanks to its flexible architecture and possession of circuit elements on itself. Sensor Circuit There are eight IR sensors and four LEDs on the follower robot. The sensor circuit of the follower robot is given in Figure 8. Fig 6: The Algorithm Of The Pioneer Robot Fig 8: The Sensor Circuit Of The Follower Robot 3.2.4. algorithm and the software The software was written in C programming language due to usage of Arduino card in the follower robot. The follower robot consists of totally 4 functions. Two of them are own functions of Arduino, while the other two are code blocks written subsequently. The algorithm of the follower robot can be seen in Figure 9. Fig 9: The Algorithm Of The Follower Robot IV. RESULTS AND EVALUATION In this study, two robots were used as pioneer robot and follower robot. It was achieved that the follower robot follows the pioneer robot in line with aimed targets. Some experiments were carried out to the robots in terms of performance in different environments, the results of them measured and necessary improvement were done. These experiments and their results are evaluated below. These experiment results are given in list on Table 1. Table 1: Light Testing Light Testing Type Daylight Environment Energy Saving Light Bulb Environment Dark Environment Performance %70 %40 %0 Some parameters have great importance in this established system. These are ground friction coefficient, rotation angle of the robots, light amount that influence the robots and follow-up distance interval. When the parameters evaluated, it was understood that the most proper values for the established system had occurred in feathered ground, at daylight and turning within the interval of 0 degrees and 30 degrees. The following distance under these conditions were measured as averagely 7 cm. While it was understood that the most adverse conditions for the established system had occurred in woolen ground, at dark and sharp turns larger than 90 degrees. Under these conditions as well as the robots can’t follow each other; also it was observed that difficulties had been experienced in their movements due to high coefficient of ground friction. Upon examining the parameters in detail, it was seen that while coefficient of ground friction increases the pioneer robot slows down and consequently the following become easier too. However upon coefficient of ground friction rises above the optimum values, movements of the robots become more difficult and it emerged that heat of the circuits had excessively increased. Furthermore it should be noted that while coefficient of ground friction increases, follow-up distance decreases. The rotating angle which is another parameter is an important value for the tracking of follower robot. Another parameter is related with light value. While this value decreases operating of the robots become more difficult and even they stop. Increasing of the light value draws the follow-up distance closer to optimum. But the most important case here is the light reflectance of the ground. The light reflected from the ground makes it more difficult to follow. V. REFERENCES [1] Murphy, R. R., “Introduction to AI Robotics”, MIT Press, London (2000). [2] İnternet: Wikipedia “Autonomous Car” http://en.wikipedia.org/wiki/Autonomous_car (2013). [3] Zabat, M., Stabile N., Frascaroli, S., Browand, F., “The Aerodynamic Performance of Platoons: Final Report”, California PATH Research Report, California (1995). [4] İnternet: Wikipedia “Platoon (automobile)” http://en.wikipedia.org/wiki/Platoon_(automobile) (2013). [5] Dávila, A., Nombela, M., “SARTRE: SAfe Road TRains for the Environment”, Conference on Personal Rapid Transit, London (2010). [6] Özkan, M., “Farklı Özelliklere Sahip Gezgin Robot Grubunun Dağıtık Kontrolü”, Doktora Tezi, Eskişehir Osmangazi Üniversitesi Fen Bilimleri Enstitüsü, Eskişehir (2007). [7] Arkin, R.C., “Behavior-Based Robotics”, John Wiley and Sons Press, England (2002).