Beginners Guide to Khepera Robot Soccer
Contents
1. oS TEAM md Create New Project Open Existing Project P Bureau K Team 2002 Cancel KT Project v2 4 Step 2 Source Navigator Projects Control Menu This screen will display all projects which already opened from current machine In this case no project was opened therefore no projects are display on the screen New Project is use to create a new project from an existing source file or create from a template file Browse is use to select an existing project which never opened from current machine 32 Open is use to open an existing project which already opened from current machine the button will be active when we selected any project in the list box on the left Delete is use to delete selected project in the list box on the left Our objective s to create a new project from existing source file then click New Project Projects Source Mavigator Sele Hew Project Browse Step 3 Create Project This screen will provide an easy way to create a new project In this example we will create a project from an existing example Braitenberg vehicle obstacle avoidance algorithm using Khepera II robot First we need to provide the new project file name and its path Click next to the text box of Project File when the open dialog has poped up change the directory to C Program Files K TProject kh2pack601 examples braiten and input braiten pr2. We can simply set a Khepera II mode by tuning an encoding wheel on the top of the Khepera to one of the sixteen modes The sixteen modes of the Khepera II can be divided into 4 main modes which are serial communication S loader user application and supporting mode Table 3 1 summarizes the available modes for the Khepera II 3 2 1 Serial communication mode This mode is designed to control all Khepera s functions using a RS232 serial line The host computer and the Khepera robot are communicating with ASCII messages Each single interaction is composed of A command begin with one or two ASCII capital letters and followed if necessary by numerical or literal parameters separated by a comma and terminated by a carriage return or a line feed sent by the host computer to the Khepera robot A response beginning with the same one or two ASCII letters of the command but in lower case and followed if necessary by numerical or literal parameters separated by a coma and terminated by a carriage return and a line feed sent by the Khepera to the host computer The commands which the host computer can send to the Khepera are of two different types Tool command used to set up the robot configuration from the host computer such as the serial command use to set a speed for the serial line communication or memory command will show the system s memory usage Control protocol used to set controls and request sensors value form
3. 64 pixels arranged along a horizontal line Each pixel gives 256 gray levels Thus the linear camera produces an image of the light intensity along a horizontal line in the scene covering 36 degrees The limited amount of visual data can be processed by the microprocessor on the Khepera enabling autonomous operation The line scanned by the camera 1s about 50 mm above the ground For a ball to be seen its diameter has to be larger than this height For this reason a tennis ball 1s used as soccer ball The colour is bright yellow to make it easier to discriminate from the other object in the playing field To make it easier to distinguish the opponent robot from the ball the robots are dressed with a jerse which is simply a paper cylinder with alternating black and white stripes The goals are painted black inside to distinguish them from the walls of the playing field which are painted n a medium shade grey Section 2 The K213 linear vision turret Because the key role of the vision sensor we start by describing the characteristics of the linear camera useful for recognising the ball the goals and the opponent robot and for determining the robot s position n the playing field 2 1 Output from the Linear Camera The K213 linear camera can provide up to 64 pixels in horizontal line with 256 grey scale with a variable frame rate of a maximum of 5 Hz The angle of view is 36 degrees The optics of the camera is fixed and set for objects between 5
4. Eo AMAAAAAAA YT 4 F C Frogram FilestkT Project hdpack BOT examplesbraten braiten c 177 lines 35 Step 6 Build Main Menu We will use this screen use to compile and build a project file into a Motorola S format Any error messages or instruction guide will display in the list box below More information for Motorola S format please consult appendix C of Motorola M68000PRM manual e www motorola com collateral M68000PRM pdf To create a Motorola S format s37 click Start Build make Source Navigator braiten Si Ed File Edit History Tools Windows Help Build command make X Start Directory C Program Files SET Project kh2pack601 examples braite nae Build Targets lt External Makefile Debug Compiling wro assembling braiten c into braten s mbsk none el goc file path prefis rke kroslibegec lib mbsk none elf 95 27 never used Assembling braten into braiten o mbek none ell goc file path prefis Vk kroslibegec libembsk none elf 95 2 never used Linking braiten o into braten s37 mEGE none elf g file path prefis Eko br gec ibmbsk nane elf 2 99 2 never used To start automatic download in RAM use Build command gmake braiten dvr To start automatic Flash memory write use Build command gmake braten flash Be ee tet et ete tet et eee et et eee et tt Compilation done rm braten s End W Reuse After finishing these 6 steps if we look in the main projec
5. Mode method mask size 7 240 200 100 Zu AQ Bil 20 Au BU e Original turret normal light f Noise filtering from figure b Figure 2 8 The image received from situation 8 the ball and the opponent in front of the goal Zu AU BU b Modified turret additional light Zu AU BU c Modified turret normal light a Playing field situation Mode method mask size 3 Mode method mask size 5 Zu AU BU d Original turret additional light Mode method mask size 7 Zu AQ Bil 20 Au BU e Original turret normal light f Noise filtering from figure b Figure 2 9 The image received from situation 9 the ball and the opponent in front of the wall and the goal 14 2 3 Panoramic Images This section will provide examples of panoramic image received from the modified linear camera with additional 150 W halogen light in different positions over the playing field The panoramic image received by taking the image at the front then rotate 36 degrees clockwise direction and take a new image the robot will iterate this action until rotated 360 degrees around itself The situations that we used to test the vision were 1 The robot stands at the centre of the playing field turned to the side wall and the ball is at the back The results are shown in Figure 2 10 2 The robot has pushed the ball until stuck at the opponent wall The results are shown in Figure 2 11 3 The ball is
6. Proximity Sensors c K Team SA 1999 File Edit View Graphical demonstration of a Braitenberg vehicle gain is optional kBraitenbergG port_reference gain Insert Tools Window Help gt gt kBraitenbergG ref Khepera Braitenberg Simulation c K Team SA 1999 File Edit View Gets ambient light sensor readings as an 8 element vector kAmbient port reference Insert Tools Window Help gt gt kAmbient ref ans 456 452 448 448 43 440 440 432 444 Gets proximity sensor readings as an 8 element vector kProximity port reference gt gt kProximity ref ans 76 44 556 1020 180 144 4 60 Gets 2 element vector of current wheel encoder values kGetEncoders port_reference gt gt kGetEncoders ref ans 19914 23198 Sets the wheel encoder positions kSetEncoders port_reference left right gt gt kSetEncoders ref 0 0 ans 0 Sets the motor speeds regulated by PID control kSetSpeed port_reference left right gt gt kSetSpeed ref 5 5 ans 0 Gets 2 element vector of current speeds kGetSpeed port_reference gt gt kGetSpeed ref ans 5 5 Stop Khepera set speed to zero kStop port_reference gt gt kStop ref Use the position controller to move to a position specified by encoder counts kMoveTo port_reference left right 44 gt gt kMoveTo ref 0 0 Set the two LEDs KLED port_reference n action gt gt kLEDCref 0 1 2 1 Sends a text s
7. Setup KTProject Setup has finished installing KT Project on your computer The application may be launched by selecting the installed icons Click Finish to exit Setup We re making a difference 3 3 2 Using KTProject After installation is finished we will get the start menu group KTProject which provide the short cut to KTProject and the short cut to Uninstall KTProject 31 faa KTProject AI IK kTProject E Uninstall KTProject We also get a short cut to C Program Files KTProject KTProject KtProject exe on a desktop ETProject We now show step by step below how to use KTProject by demonstrating opening and compiling an example in the package First execute KtProject exe please not confuse with installation package KTProject exe by double click on the desktop icon click on the short cut menu or directly select C Program Files K TProject K TProject KtProject exe Step 1 Choose project option This screen will ask whether to create a new project or open an existing project For both creating and opening a project task it is better to choose an Open Existing Project option The reason forl not useing Create New Project option is that the software tends to crash and needs to be reopened when trying to create a new project by using an available example file but the problem does not occur when using Open Existing Project option Click Open Existing Project K Team Project Front End Sele
8. and the opponent in front of the wall the results are shown in Figure 2 7 8 The ball and the opponent in front of the goal the results are shown in Figure 2 8 9 The ball and the opponent in front of the wall and the goal the results are shown in Figure 2 9 In Figure 2 1 to Figure 2 9 different lines style will correspond to the different distances from the object as shown below 10 centimeters apart from the object 30 centimeters apart from the object 50 centimeters apart from the object In Figure 2 1 to Figure 2 9 subfigures a display the location of the objects in the playing field corresponding to each situation Subfigures b are display the images when using the modified turret with addition halogen light Subfigures c display the images when using the modified turret with normal ambient light Subfigures d display the images when using the original turret with addition halogen light Subfigures f display the images when using the original turret with normal ambient light Subfigures g display the results when applying noise filtering to the image of subfigure b using mode method with mask sizes 3 5 and 7 240 200 100 F 20 40 60 b Modified turret additional light 240 200 100 20 Au BU c Modified turret normal light a Playing field situation Mode method mask size 3 Zu AU BU d Original turret additional light 20 Au BU e Original turret nor
9. at the centre and the robot facing the opponent goal direction The results are shown in Figure 2 12 15 Original Panoramic Noise filtering using average method mask size 7 Noise filtering using median method mask size 7 Noise filtering using mode method mask size 15 Noise filtering using mode method mask size 7 Noise filtering using mode method mask size 3 Figure 2 10 The panoramic image received from situation 1 16 Original Panoramic Noise filtering using average method mask size 7 Noise filtering using median method mask size 7 Noise filtering using mode method mask size 15 Noise filtering using mode method mask size 7 Noise filtering using mode method mask size 3 Figure 2 11 The panoramic image received from situation 2 17 Original Panoramic Noise filtering using average method mask size 7 Noise filtering using median method mask size 7 Noise filtering using mode method mask size 15 Noise filtering using mode method mask size 7 Noise filtering using mode method mask size 3 Figure 2 12 The panoramic image received from situation 3 18 2 4 Vision Turret Modifications As mentioned earlier the automatic control of the frame rate of the K213 turret 1s a nuisance rather than an asset for robot soccer and it should be turned off To achieve this task we need to send a constant frequency to the linear light sensor chip TSL
10. for obstacle avoidance Test mode Successive tests are performed and the results are displayed using the serial link Flash Erasing mode The user segment of the nonvolatile memory is erased uKos upgrade mode Khepera BIOS upgrade mode 26 Table 3 1 summarized the available modes of Khepera II Number bits s Serial Mode to control the robot using the Serial communication communication protocol The robot should be connected to a terminal using the S cable 8 57600 9 115200 S loader Robot waits for an application to be transferred 6 38400 in RAM and executes it when fully uploaded User Start an application stored n the robot s non application 57600 volatile memory The application should be flashed first using the S loader algorithm for obstacle avoidance IT Beer the results are displayed using the serial link nonvolatile memory s erased CD Reserved The serial link setup 1s always 8 bit start bit 2 stop bit no parity Only the baud rate can be changed The encoding wheel position can be changed at any time If the robot is running a reset 1s necessary for the setup to be effective The reset button can be used at any time to reset the robot 3 3 Installation and Using KTProject Package As we mention above in section 3 2 the Khepera robot has the ability to run fully autonomous by executing the program in its RAM or flash memory Executable files which can be loaded into the Khepera h
11. the robot such as set the motor speeds read proximity sensor values 3 2 2 S loader mode The S loader mode is used to load any user application into the robots RAM and execute it when finished downloading Two different methods are available to start the S loader First when booting the Khepera in the S loader Second booting in serial communication mode and sent the command run sloader Once started the S loader simply waits for an executable file to be transferred through the serial line Different terminal emulators will have different methods to send a file but the most common is to use a send file command from the terminal emulator As soon as the loading process is initiated one of the Khepera s LED indicator is switched on The indicator should stay on during the entire loading process and be turned off when the download s completed The downloaded application is executed as soon as the transfer is achieved 3 2 3 User application mode This mode is used for a completely autonomous execution of a user application The application has to be uploaded n the robot s non volatile memory using a serial link and can be executed at boot time 25 To upload an application in non volatile memory the instructions below have to be followed Set the robot to serial communication mode Use the sfill command to start the loader The message S format Motorola loader mode should be displayed Send the application f
12. 0 and 500 mm to be n focus However considering that one pixel covers 0 5 of a degree which at 500 mm makes 4 3 mm on can see that resolution is set by the number of pixels and not by the focus There is not noticeable deterioration of resolution well beyond 500 mm distance The linear photosensor array TSL213 consists of 64 discrete photo sensing areas called pixels Photons striking a pixel generates a charge in the region under the pixel The amount of charge accumulated in each element is directly proportional to the amount of incident light and the integration time After the integration period is finish the signals in each pixels are transferred to the TSL213 output and the charge values in each pixels are reset Normally a pixel from a bright object will give a higher value than a dark object The bright tennis ball should give the highest value follow by the grey wall and the black goal will be the lowest However if the scene is very bright all pixels could have a high value and the brighter parts could make the pixels saturate To maintain the image contrast over a wider range of scene brightness the K213 linear vision also has ambient light sensor TSL230 The ambient light sensor controls the exposure that is the time available for integrating the light incident the photosensitive array The function of TSL230 is to control the scanning speed to TSL213 to suit the current lighting condition The more ambient light the shorter
13. 2 numbers separated by a comma and terminated by a line feed These numbers are the values of the position counters of each wheel Type the protocol command G 0 0 followed by a carriage return or a line feed This command set the position counters to the 2 values given as parameters The answer 1s composed by a g and a line feed Retry the protocol command H to verify that the G command has been executed Type the protocol command C 1000 1000 followed by a carriage return or a line feed The robot respond with c and goes forward 80 mm Retry the protocol command H to verify the final position 39 H Tera Term COM1 VT E lolxi File a control Window Help fF 00000 Kernel Operating System ji H d 7 a i Moy Ls edoardo f ranzi ukos ch ah vie es a Zn implementation for E Team CALM Exxx implementation Desisn Development by Edoardo Franzi All rights reserved ROM of minirobot KIT Edoardo Franzi September 1 2001 Rev 6 01 beta serial Communication Protocol 0 6 01 88 EU 12 52 96 152 72 16 12 96 924 508 980 164 72 4 a 7 5 For more protocol commands please refer to appendix A of Khepera II user manual http www k team com download khepera documentation Kh2UserManual pdf Step 6 Test to send executable file in Motorola S format s37 Before we can send any files to the Khepera we have to change the running mode to S loader mode Two different methods are available to start
14. 213 Two effective solutions are available to accomplish this First a normal LED will be attached in the ambient light aperture to give constant illumination to the TSL230 The second solution is to replace the TSL230 with an adjustable frequency oscillator and use the output from the oscillator to control the scan rate of the TSL213 a LED solution For the LED approach we can use a simple LED circuit with variable resistors This circuit will provide varying brightness according to the current value of a set of resistors A sample of LED circuit is shown in figure C 2 This circuit has a 270 Q fixed resistor and two variable resistors 50k Q and 5k Having two variable resistors will easier to settle brightness as compared with only one variable resistor To use this LED circuit with the vision turret we need to connect ground and Vcc to pin 2 and 5 of the outer pin of K213 turret respectively The first pin is on the left side when looking from the back of the camera as shown in figure C 3 In fact we can connect the ground of the LED circuit to any ground pin 4 of the TSL230 or pin 6 or 7 of the TSL213 and also can connect the Vcc to any Vcc pin 5 of the TSL230 or pin 4 or 8 of the TSL213 as shown in figure C 4 For the example in figure C 3 we connect ground to pin 6 of TSL213 and connect Vcc to pin 5 of TSL230 After connecting the circuit with K213 we have to put the LED in TSL230 hole and block it with black elect
15. Beginners Guide to Khepera Robot Soccer Narongdech Keeratipranon and Joaquin Sitte Smart Devices Lab School of Software Engineering and Data Communications Queensland University of Technology Brisbane Qld Australia e mail j sitte qut edu au Brisbane 2003 Section 1 Introduction The purpose of this guide is provide initial help for setting up Khepera robots to play an autonomous simplified game of soccer whether it is just for the fun of it or for participating in the Kheperasot robot soccer tournament organized by the Federation of International Robot soccer Association FIRA This guide has the following sections FIRA Kheperasot game rules The Khepera robot soccer facility consists set up a Khepera robot soccer environment consists of a playing field robot computer communication and software development 1 1 Background Playing a soccer like game with small mobile robots s not only great fun for technology fans but also great technical challenge and educational experience Numerous categories are open to competitors under the umbrella of two international championships the RoboCup and the FIRA World Cup The various leagues are quite demanding though in terms of resources and effort required from the participants Often quite sophisticated robots have to be built Five or more of them are required for a team and the playing fields are of the size of small room In many cases powerful computer vision are required Not surprisingl
16. Mouse Don t create a Start Menu folder Cancel 29 Step 5 Select Additional Task This screen will ask what additional tasks should be performed In this case it only has one option create a desktop icon that should be ticked then click Next v Setup KTProject Select Additional Tasks Which additional tasks should be performed 2 coy Select the additional tasks you would like Setup to perform while installing ET Project then click Nest Additional icon Create a desktop icon Step 6 Confirmation This screen will summarize what is going to be installed if everything is correct then click Install v Setup KTProject Ready to Install Setup is now ready to begin installing KT Project on your computer Click Install to continue with the installation or click Back if you want to review or change any settings Destination directory C Program Files K T Project Start Menu folder ET Project Additional tasks Create a desktop icon Step 7 Progress of Installation The installation has begun and KTProject will be ready to launch soon 30 Setup KTProject Installing Please wait while Setup installs KT Project on pour computer Extracting files Cy AKT Project SN 451 Aeharedemos co demordlishi demosplus minus server cc 16 Cancel Step 8 Finish The installation package will show the completed installation screen click Finish
17. To set up serial port click Setup gt Serial port This screen will use to configure serial port property according to Khepera mode Port select according to current connection port Baud rate select according to Khepera mode please refer to section 3 2 in this case using mode 8 serial communication with baud rate 57600 Data always set to 8 bits Parity always set to none Stop always se to 2 Flow control and transmit delay use its default values 37 Tera Term Serial port setup Port Baud rate Data Cancel Parity stop Help Flow control Transmit delay 0 msecichar 0 msecfline Step 3 Main screen of Tera Term Pro After finishing with setting up the serial port press reset button of the Khepera The screen should look like figure below this example the running mode is set to mode 8 serial communication H Tera Term COM1 YT El jofx File Edit Setup Control Window Help eo 1992 2001 Edoardo Franzi ukernel Operating System edoardo f ranz i Rukos ch implementation for E Team w CALM Besse implementation Design amp Development by Edoardo Franzi All rights reserved ROM of minirobot KIT Edoardo Franzi September 1 2001 Rev 6 01 beta serial Communication Protocol Step 4 Terminal setup To work in serial communication mode we better enable Local echo function because we will able to see the command we typed To open the terminal setup scr
18. a multiple line response To send a command that returns a single line response we have to use return value kcmd port reference khepera command To send a command that returns a multiple line response we have to use return value kcmd port reference khepera command 1 The reason why we have to distinguish these two command type is the single line command returns everything it receives from Khepera until it receives a newline character In the other way the multi line command waits for timeout seconds and then returns everything in the buffer For the multi line we have to do like this because it doesn t know how long the response will be The choice of timeout is therefore important Too small multi line responses will be truncated too long the command will take a long time to return One second timeout 1 is recommended and corresponds to 48 lines of 80 column text at 38400 baud Below is the sample of command for the Khepera II To return the system bios version single line gt gt kcmd ref B ans b 6 00 6 01 To list currently running processes multi line gt gt kcmd ref process 1 ans Process N 00000000 IDLE process for the uKOS micro kernel EF 2001 Rev 2 00 Process N 00000001 Start up process of the KII EF 2001 Rev 6 01 Graphical histogram or polar plot display of proximity sensor readings kProximityG port_reference gt gt kProximityG ref 42 Khepera
19. ave to be compiled and converted into Motorola S format K Team provides a GNU C cross compiler and the KTProject interface which can generate the executable files KTProject is a graphical C development environment for Windows platform This package provides a library of all the low level functions for Khepera and its extension turrets including motor control sensor reading communication multi tasking management and linear camera reading The package also includes the GNU C compiler the Cygwin Environment copyright RedHat Inc Source Navigator copyright RedHat Inc KTDebug and serial port terminal Tera Term Pro 21 3 3 1 KTProject Step by step Installation Guide Information in this section is based on KTProject Version 2 2 by P Bureau K Team 2002 The package is self executable 26Mb compatible with Windows 32bits environment such as Win 95 98 98SE Me NT 2000 and XP and can be downloaded for free at ftp ftp k team com pub cross compiler KTProject KTProject exe After downloading KTProject 2 2 double click on the download file The complete download version is called KTProject exe Step 1 Confirmation of Installation Set up package will ask to confirm installation KTProject click Yes N This will install KTProject Do you wish to continue Step 2 Greeting Message This screen will provide a greeting message and some recommendations to close all applications before continuing click Next v Se
20. ectory Type JE u EEE Makefile others ENBMOTORS rma KNBSENSORSIMa KSCALING mal KSPEEDImaj mainiful process Oljful process 1 fu f process fu WiIDProcess g Makefile others Step 5 Source Code Editor 34 This screen will display the source code of desired file We can modify any code directly via this interface More information on how to write C Code for Khepera II please consult Khepera II programming manual and Khepera BIOS reference manual http www k team com download khepera documentation Kh2ProgrammingManual pdf http www k team com download khepera documentation KheperaBIOSRefManual pdf To compile a project click on the menu bar Tools gt Build from Source Navigator Symbols Main Menu Window or Source Code Editor Window braiten c Source Nayigator braiten File Edit Search Tools History Windows Help Author Franzi Edo The 03 04 98 Modifs Project KHEPERA anal This PRM launches 3 processes Process 0 alive it toggles the LED 0 every 500 ms Process 1 it publishes an IR sensor association Process 2 it implements a Braitengerg vehicle 3 obstacle avoidance algorithm This module is ce of Edoardo Franzi 1332 1333 franzi k team com ard include lt 5ws Kkos N gt include lt Std1ib h include cstdio Is deTi ne KMBSENSORS 15 deTi ne KE MNBMOTORS 2 deTine K SCALING 400 derfine ESPEED 20 static int32 wloOProcess 3 5 Process N
21. een click Setup gt Terminal If we want to enable Local echo property check the box n front of Local echo 38 Tera Term Terminal setup Terminal size Newline 180 24 Receive cp Term size win size Transmit CR Lancel OK Auto window resize Terminal ID YT100 Answerback Auto switch WT lt gt TER Help Step 5 Test some protocol commands Now we are ready to communicate with Khepera II via the serial link Below is a sample of protocol command for the Khepera II Type the capital letter B followed by a carriage return or a line feed The robot must respond with b followed by an indication of the version of software running on the robot and terminated by a line feed Type the capital letter N followed by a carriage return or a line feed The robot must respond with n followed by 8 numbers separated by a comma and terminated by a line feed These numbers are the values of the robot proximity sensors Retry the same command N putting some obstacles in front of the robot The response must change Type the protocol command D 5 5 followed by a carriage return or a line feed The robot must start turning on the spot and respond with d and a line feed To stop the robot type the protocol command D 0 0 followed by a carriage return or a line feed Type the protocol command H followed by a carriage return or a line feed The robot must respond with h followed by
22. ems programming control or computational intelligence course Khepera is a miniature robot originally designed as a research and teaching tool in the Swiss Research Priority Program It was first implemented in 1992 by a research team from the Microprocessor and Interface Laboratory LAMI at the Swiss Federal Institute of Technology Lausanne EPFL and 1s currently developed by K TEAM SA Switzerland The Khepera robot is now widely used around the world as a platform for various robotics experiments and applications Researchers can easily extend Khepera s capability by attaching it with additional desired modules such as a gripper module video module or linear 2 vision module It has two motor driven wheels and is equipped with 8 infra red sensors allowing it to detect obstacles all around it in a range of about 5 cm The Khepera robot is a two wheeled robot with a cylindrical shape 70 mm in diameter and 30 mm high The robot has 8 infra red proximity sensors two independent motors for differential steering and two encoders to measure wheel rotation Because there are several expansion modules called turrets that can be stacked on the top of the Khepera robot the bare Khepera robot is also called the Khepera base Proximity sensors alone are not enough to allow the robot to play a soccer game The K213 linear camera turret provides simple vision capability enough to perceive objects at a distance The linear camera has a detector with
23. ile to the serial line the same way as using in S loader mode As soon as the transfer is in progress an LED indicator is switched on and will stay on until the transfer 1s completed The application is transferred into the robot s RAM and still needs to be flashed When completed the message S download terminated should be displayed Erase the robot s non volatile memory using the flash E command When completed the message FLASH user segments erased should be displayed Write the application into the flash memory using the flash W command When completed the message FLASH user segments written should be displayed After uploading the application into non volatile memory it will stay there until it is erased using the flash E command The loaded application can be executed at any time using one of the two following methods If a serial communication link is already up we can use the command run user flash to execute the user flash segment The messages Run the selected application and Execute a user FLASH application should be displayed For a completely autonomous execution set the encoding wheel position to the user application mode and reset the robot The user flash segment 1s automatically executed at boot time 3 2 4 Supporting mode This mode is an additional mode to support usage of the Khepera The supporting modes are Demonstration mode Braitenberg vehicle algorithm
24. mal light f Noise filtering from figure b Figure 2 1 The image received from situation 1 the ball in front of the wall 240 200 100 Zu AU BU b Modified turret additional light Zu AU BU c Modified turret normal light a Playing field situation Mode method mask size 3 Mode method mask size 5 Zu AU BU d Original turret additional light Mode method mask size 7 Zu Au BU 20 Au ai e Original turret normal light f Noise filtering from figure b Figure 2 2 The image received from situation 2 the ball in front of the goal Zu AU BU b Modified turret additional light Zu AU BU c Modified turret normal light a Playing field situation Zu AU BU d Original turret additional light e 40 ED 20 Au BU e Original turret normal light f Noise filtering from figure b Figure 2 3 The image received from situation 3 the ball in front of the wall and the goal 240 200 100 Zu AU BU b Modified turret additional light al 40 60 a Playing field situati c Modified turret normal light a Playing field situation Zu AU BU d Original turret additional light 20 AQ BU e Original turret normal light f Noise filtering from figure b Figure 2 4 The image received from situation 4 the opponent in front of the wall 240 200 100 Zu 40 BU b Modified turret additional light Z
25. o be used with text mode terminal program or use with Matlab or LabVIEW which can provide a nice graphic user interface 3 1 Configuration for Robot Computer Communication Download a program to the Khepera robot we need to connect it a host computer The host computer will send any commands to the Khepera through a serial link using a standard RS232 line while the interface module converts the RS232 signal into an S serial signal to communicate with the robot In another way the robot also sends back any information via S serial signal and will be converted to RS232 signal by the interface module From the above description the robot computer communication system is composed of mainly six components Host computer Standard RS232 cable Interface module S serial cable AC DC adapter power supply Khepera Figure 3 1 shows the configuration for communication between the Robot and a host computer If we want to use an internal battery power we can neglect AD DC adapter connection and set the battery switch to ON position In general we only use internal battery when working in fully autonomous mode Figure 3 1 Configuration for communication between the Robot and a host computer 3 2 Running Modes of Khepera II A Khepera can be set to work in many configuration modes such as serial communication S loader or user application Different modes will have different operations and also different 24 methods to handle
26. oj in the File name text box Then click Save Second in Add Directory text box we need to provide the project directory which is C Program Files KTProject kh2pack601 examples braiten Third we need to copy a Makefile a file that contains compilation options from C Program Files KTProject kh2pack601 examples Makefile which has the suitable options for Khepera II into C Program Files KTProject kh2pack601 examples braiten To do this we can use any file management program such as Windows Explorer When you have finish these three steps click OK button 33 Auto Create Project Do you want to automatically create a Source Navigator Project based on Project File Project kh2pack60T examples breiten braiten pro m Add Directory fam Files ProjecthkhepackbOT examples braten mone M Include Subdirectories I Build Cross Reference database Project Editor Cancel Step 4 Source Navigator Symbols Main Menu This screen will provide information of the current project and also detail of each files More information on how to use Source Navigator please consult Online manual by clicking at Help menu and then Online manuals To modify some source code we can double click on that particular file Symbols Source Navigator braiten ER Symbols Source Navisator braiten Seles File View Tools History Windows Help File View Tools History Windows Help Pattern Search Dir
27. or frequencies and value of variable resistors Frequency Hz Variable resistor k Q 102 5 5 To use this oscillator circuit with the vision turret we need to remove the TSL230 chip from the camera and connect ground Vcc and output of oscillator circuit to pin 4 5 and 7 of the inner pin of K213 turret respectively The first pin is on the right side when looking at the back of the camera opposite of the LED solution where the first pin is on the left side If we look at schematic of TSL213 and TSL230 in Figure C 4 we connect ground to pin 4 of TSL213 Vcc to pin 5 of TSL230 and output to pin 6 To remove TSL230 chip first we need to take the black plastic case around the sensors off The case is fixed on the PCB with a soft silicone joint We need to cut gently through this joint using a slim cutting tool After this we can easily remove TSL230 from its socket 21 Jib le UNI Tia Le ur i m i m le Jif Output Jig Jih O000 C VOC Rl 470k 470k Trigger Discharge Output Threshold P Reset Control 100 l nF Figure C 16 Oscillator circuit with one variable resistor 22 2 5 Keperasot robot jersey template Section 3 Set up and Using Khepera The Khepera robot can operate with or without a connection cable execute received over the serial connection or executed program downloaded program and use an internal or external power source Khepera can als
28. otocol These modules are available for free at http www k team com download khepera matlab KheperaMatlab win32 zip When have KheperaMatlab win32 zip please extract all kMatlab files to a directory on your hard disk Then run MATLAB and add the kMatlab directory to the MATLAB path To do this click File gt Set Path and then click Add Folder enter or Browse for the kMatlab directory click OK Save and Close To use MATLAB to communicate with a Khepera we need to set the running mode to serial communication please refer to section 3 2 in this example will use running mode 8 serial communication with baud rate 57600 We will step by step below show how to use MATLAB to communicate with Khepera More information please refer to readme txt and m in kMatlab directory Step 1 Open serial port kMatlab has provided kopen function to open serial port which is of the form port reference kopen com port baud_rate timeout In our case we will use COMI at 57600 baud with 1 second timeout for the first argument 0 means COMI 1 means COM2 and so on gt gt ref kopen 0 57600 1 If message Undefined function or variable kopen occur then you are not in the correct directory or you have not set up your path correctly 41 Step 2 Send commands Command which can be sent to Khepera can be divided into two group first the command return a single line response and the second return
29. rical tape to make the LED stable and prevent intervention between LED and environmental light For the tuning process we should set a 5k resistor to approximately 2 5k then using a 50k resistor as a rough tuning and 5k as a fine tuning VCC pin 5 of the turret which is pin 5 of TSL230 R 270Q Variable R 0 50kQ Variable R 0 5kO LED GND pin 2 of the turret which is pin 6 of TSL213 Figure 2 13 LED circuit with two variable resistors 19 Top view LED has to be placed to close this hole TSL230 TSL213 lens Figure 2 15 Schematic of K213 Figure 2 14 Connect LED circuit with K213 vision turret Side view 20 Front chip view 765 2S 4 TSL230 TSL213 b Oscillator solution For this solution we can use a 555 oscillator circuit with variable resistors This circuit will overtake a function of TSL230 create a refresh rate signal and will send the output directly to TSL213 From this concept we can achieve any refresh rate of K213 by varying the value of a resistors A sample of an oscillator circuit is shown in figure 2 16 this circuit has a 100k Q variable resistors The output frequency from the oscillator can compute by using equation 2 1 1 44 2 1 R1 2x R2 xC From the equation we can select any desired frequency by tuning variable resistor Table 2 1 show the major frequencies and their correspondent resistor values Table 2 4 Oscillat
30. scanning speed to prevent the saturation of photo sensing elements in TSL213 Such as at the goal region which has a less light than the wall region the frequency output from the TSL230 will lesser that mean the TSL213 will use more time to collect the image information and smaller differences in the low light intensity area will be enhanced Unfortunately the usefulness of this exposure control method greatly diminished by what seems to be a design fault The problem is that the aperture of the ambient light sensor is not a narrow slit corresponding to the linear camera but a cone of approximately the same hight and width Thus the brightness of the scene above and below the line scanned by the TS1213 will contribute to the ambient light signal For example a light background above the goal will keep the scan rate higher than desired From this reason t has been found that it is better to disable the adaptive scanning frequency from TSL230 and use a constant frame rate all over the playing field To get a constant frame rate we need to send a constant frequency to TSL213 Two effective solutions are available to accomplish this First a normal LED will be attached in the ambient light aperture to provide constant illumination of the TSL230 The second solution is to replace the TSL230 with an adjustable frequency oscillator and feed the output into the TSL213 These modifcationa are described in detail in section 2 4 below The LED solution is eas
31. t directory C Program Files K TProject kh2pack601 examples braiten will have braiten c a source file braiten o an object file braiten proj a project file braiten s37 an executable file in Motorola S format which will be downloaded into Khepera Makefile a compilation script file Snprj a directory used in the compilation process 36 3 4 Using Tera Term Pro Tera Term Pro is a free terminal emulator for Microsoft Windows operating systems The emulator is included in KTProject package and will be installed in directory C Program Files KTProject Kterm Tera Term Pro can used to communicate with Khepera in every running mode Before using the emulator the serial link between the host computer and the robot has to be properly configured Please refer to section 3 1 for a detailed description of necessary connections and configuration We will show step by step below how to use Tera Term Pro to communicate with Khepera More information in using Tera Term Pro please refer to Tera Term Pro homepage http hp vector co jp authors VA002416 teraterm html First execute C Program Files K TProject Kterm ttermpro exe Step 1 Choose connection type This screen will ask the connection type to connect with Khepera select Serial and choose the connect communication port Click OK Tera Term New connection TCRAR r Serial Port IM Cancel Help Step 2 Serial port setup
32. the S loader First when booting the Khepera in the S loader mode please refer to Table 3 1 Second booting in serial communication mode and command run sloader Currently we are already in serial communication mode then type run sloader After typing the command the messages Run the selected application and S format Motorola loader mode should display we have to select the file we want to send in this case will use braiten s37 Click File gt Send file and then select C Program Files K TProject kh2pack601 examples braiten braiten s37 which we receive after building braiten project to build a project please refer to section 3 3 The download dialog will pop up while downloading the file The downloaded application 1s executed as soon as the transfer is achieved In this case the Khepera will move around and avoid any obstacles please put the Khepera on a flat surface that is safe for the robot because it will move rather quickly and cover long distances n a short time 40 Ay E Tira Torme Serni fie Far ame braitensd Bytes transfered 65300 Close _ Pause Hap reji Er Fr TE DS Mon PS E GE SS 3 9 Using MATLAB MATLAB is well known software produced by The MathWorks Inc that allows powerful computation and visualization of scientific data K Team provides MATLAB modules to access the robot functionality via an RS232 serial cable using K Team s SerCom communication pr
33. tring command to an extension turret kTurret port reference turretID textString This example will get 64 pixels with 256 grey level image from linear camera The robot has attached K213 linear camera more information about linear camera please see detail at section 2 gt gt kTurret ref 2 N ans n 28 28 26 23 23 19 20 19 20 18 18 19 18 22 17 21 19 21 22 20 20 2 0 19 22 21 19 21 26 22 32 48 112 160 240 240 240 240 240 240 240 240 240 240 240 240 240 240 240 240 192 144 96 48 24 21 19 17 18 18 17 18 18 18 16 If the robot doesn t attach K213 linear camera the MATLAB response should be ans I For more protocol command please refer to appendix A of Khepera II user manual http www k team com download khepera documentation Kh2UserManual pdf Step 3 Close serial port kMatlab has provided kclose function to close serial port which is of the form kclose port_reference In this case we use ref as a variable for port reference gt gt kclose ref 45
34. tup KT Project Welcome to the KTProject Setup Wizard This will install KT Project 2 2 on pour computer It is strongly recommended that you close all other applications you have running before continuing This will help prevent any conflicts during the installation process Click Next to continue or Cancel to exit Setup We re making a difference Step 3 Destination Direction 28 This screen will ask the folder where it will keep the KTProject application We recommend to keep the destination direction as it was in this case C Program Files KTProject thus reducing the trouble for future assistance from any other sources click Next v Setup KT Project Select Destination Directory Where should KT Project be installed fr Program Files C ACD Systems DI Adobe C5 aod i Apaintek DO AreSoft ID AvantGo The program requires at least 75 1 MB of disk space Step 4 Start Menu Folder This screen will ask for the start menu folder name We recommend to keep the folder name as it was n this case KTProject click Next v Setup KT Project Select Start Menu Folder Where should Setup place the program s shortcuts Select the Start Menu folder in which you would like Setup to create the program s shortcuts then click Next Accessories ACD Systeme Administrative Tools Adobe Adobe Acrobat 4 0 ArcSoft Videol mpression AvantGa Documents To Go FinePix iewer Games Benius PowerS croll
35. u AU BU c Modified turret normal light a Playing field situation Mode method mask size 3 i Zu AU BU d Original turret additional light 20 Au ai e Original turret normal light f Noise filtering from figure b Figure 2 5 The image received from situation 5 the opponent in front of the goal 10 Zu 40 BU b Modified turret additional light Zu AU BU c Modified turret normal light a Playing field situation Mode method mask size 3 Mode method mask size 5 Zu AU BU d Original turret additional light Mode method mask size 7 Zu Au Bil 20 Au ai e Original turret normal l ght f Noise filtering from figure b Figure 2 6 The image received from situation 6 the opponent in front of the wall and the goal 11 240 200 100 Zu AU BU b Modified turret additional light Zu AU BU c Modified turret normal light a Playing field situation Mode method mask size 3 Zu AU BU d Original turret additional light 20 Au BU e Original turret normal light f Noise filtering from figure b Figure 2 7 The image received from situation 7 the ball and the opponent in front of the wall 12 Zu AU BU b Modified turret additional light Zu AU BU c Modified turret normal light Mode method mask size 3 Mode method mask size 5 240 20 40 60 00 d Original turret additional light ma
36. y teams of advanced undergraduate and postgraduate engineering students from universities dominate the tournaments The Kheperasot http www fira net league from FIRA Federation of International Robot Soccer Associations offers a challenging game yet the entry cost is significantly lower than for most other leagues There is no need to build robots as the Khepera robots are commercially available general purpose research robots A Khepera robot is of the size of a small coffee cup and thus the playing field can be small enough to fit on a desk or table There is no expensive external vision system and no wireless communication In its simplest form only one robot is needed per team The technical challenge in this league resides in programming the robots to play a truly autonomy of soccer playing robots Once a robot is let loose on the playing field it has to fend with its own sensors and computing resources The robot has be capable of locating itself in a simplified environment recognize landmarks goals and other moving objects ball opponent and move quickly and purposefully to outsmart the adversary And it has to achieve all this with the sensing and computing devices fitting in such a small robot A C programming environment and two simulators support software development Creating a moderately competent player is within the reach of a two student team in couple of weeks and is suitable as a practical semester assignment in an embedded syst
37. y to implement and gives good results A further advantage of disabling the automatic scan rate control is that the scan rate can be adjusted fit the overall illumination level for example when setting up the playing field in a different place 2 2 Typical Images This section will provide examples of output received from the linear camera in both original and modification case additional light and normal ambient light near and far from the objects and also with different soccer objects We will set the variable resistance of LED circuit to 55k Q if only normal ambient light is used a photo meter measured 200 lux at this condition And will set the variable resistance to 40k Q in case of using additional 150 W halogen light a photo meter measured 500 lux at this condition We will use three distances 10 30 and 50 centimetres away from the objects to test the robot vision We used following situations to test the camera 1 The ball in front of the wall the results are shown in Figure 2 1 2 The ball in front of the goal the results are shown in Figure 2 2 3 The ball in front of the wall and the goal the results are shown in Figure 2 3 4 The opponent robot n front of the wall the results are shown in Figure 2 4 5 The opponent robot in front of the goal the results are shown in Figure 2 5 6 The opponent robot in front of the wall and the goal the results are shown in Figure 2 6 7 The ball
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