Mine Sweeper - Machine Intelligence Lab
Contents
1. Burr Brown OPT101 built in amplifier photodiode is a little clear plastic 8 pin DIP One photodiode is used as a red color detector to prevent from running into fixed mines Another will be used as a flash light detector to go back to it starting location The digital outputs is in the range 1 to 218 about 7 5 bits of precision Behaviors The Mine Sweeper knows to go straight turn around 180 or 360 to look for IR or flash light backup and go around when detect a fixed or magnetic mine An IR emitter is assumed to be turned off when the robot detects the white area at the corner Outputs LE 68HC11 E9 sa O o e 0 wheels Photodiode O IR Sensor O Bump Swicth E EMF Detector Forwarding Avoid Fixed Mines Experimental Layout The robot will start from the middle of one of the sides of the mine field It has to detect and turn off all 4 emitters at 4 corners Only one corner will be turned on at a time After completing the mission the robot will look for a flash light signal and go back to its starting location Besides the IR mines 5 other mines are also on the field Four of them are at fixed locations and the magnetic mine is at random location 6 8 FEET HE ls INCHES Fixed Mine 5 FEET Sa IR Emitter Playing Surface Fig 1 Mine Field Lay Out Cost Estimate 1 Servo Kit MIL ablandar 40 00 2 Sensor Kit MIL ainia 25 00 3 Nov2. IR_LEFT gt THRESHOLD2 amp amp IR RIGHT gt THRESHOLD1 II MAGNET gt 40 go around left sleep 3 else if TOUCH FRONT go back left sleep 25 go forward else if TOUCH REAR go_fast sleep 1 5 else if CENTER gt THRESHOLD3 stop g00 else go forward defer void find IR while 1 if start 0 go forward sleep 3 5 stop g00 start 1 if round lt 4 if IR_LEFT gt 89 amp amp IR_RIGHT lt 89 amp amp search_IR 1 go_around_left else if IR_LEFT lt 89 amp amp IR_RIGHT gt 89 amp amp search_IR 1 go_around_left else if BEACON gt 90 go_forward search_IR 0 wait 300 else if BEACON lt 87 amp amp permit 0 search_IR 1 else if CENTER gt 60 search_IR 0 permit 1 round go_around_left sleep 3 5 go_forward 15 sleep 2 0 wait 400 permit 0 else go_around_left if round defer void find_lite while 1 if round gt 4 if round 4 go_around_left sleep 1 0 go_forward wait 300 round if LIGHT gt 40 amp amp round gt 4 go_forward else if LIGHT lt 40 amp amp round gt 4 go around left wait 300 go forward sleep 1 5 defer int start 0 int round 0 int permit 0 int search IR 1 int LEFT RIGHT CENTER IR LEFT IR RIGHT BEACON LIGHT MAGNET TOUC
3. E9 is a 8 bit MCU which has many advanced features for this project A Talrik Junior TJ platform which is produced by Novasoft is suitable for this project because of its round shape 6 1 2 inches in diameter and light weight The sensory system includes some different types of sensors such as Bumper sensor IR sensor Magnetic Field sensor and Photodiode Introduction Today there are millions of acres of mine fields around the world and thousands of innocent people are killed and injured every year To minimize human loss an autonomous machine can be designed to deactivate the mine fields by itself The robot can be intelligent enough to handle the job without remote control from a human This project is not the first attempt in this field however my primary goal is designing an inexpensive efficiency and reliable robot which can deactivate a mine field in the shortest time and consume the least energy My robot will use a Motorola 68HC11 E9 microcontroller A TJ platform is suitable for this project There are six integrated behaviors that use 4 types of sensors The robot will look for IR light which is emitted from one of four mines on four corners and deactivate the mine It will also know how to avoid magnetic mines and some other obstacles Specifications e System self operating IR detector range 10 feet Magnetic sensor sensitivity 5 to 8 from a 1 diameter coil 5 5 kHz Red Color Detector Response Time le
4. EEL 5666 Intelligent Machine Design Laboratory Professor Keith Doty Project MINE SWEEPER By Nick H Nguyen Electrical and Computer Engineering Department University of Florida TABLE OF CONTENTS Table of Contents DA ANSE ee ee ee ce 2 PD BRA 0 A tees een tens ERE 3 INTO AUC e co A eg E dee 4 Seri ll OM Gy O A RNA AAA ne ee 4 Intestated Systemics e eds do ol 5 Mobile Plato in e e di oe hl ana 5 ACUM A AA A A AS 5 A O 6 BELO ii A A DA r rr r rrr AAA 6 Experimental Layout dd 7 Cost Estates tdo le a 8 CONCISA LN ENE EEE EE e eN Oss 8 Documentations DD eee g gg 9 A DD DD DD RO E ae ea gerege 10 Abstract The Mine Sweeper is a mine deactivating robot It is supported to handle the job by itself without remote controlling The robot is supposed to detect and deactivate four IR mines at four corners of the mine field avoid four red mines and one magnetic mine then return to its starting location by following a flash light The mine field is 5 x6 3 4 flat white surface A 5 white wall surround the playing surface There are four fixed mines that can be recognized by 6 red square painted around the mine and they are located half way from a corner to the center of the mine field Also there is one random magnetic mine The IR transmitters will be located 3 above the playing surface A Motorola 68HC11 EVBU board with E9 version MCU and Novasoft ME11 expansion board is the robot s integrated system The M68HC11
5. H int FRONT 1 int REAR 2 int THRESHOLD1 120 int THRESHOLD2 125 int THRESHOLD3 20 int LEFT MOTOR 0 int RIGHT MOTOR 1 float SLOW_SPEED 20 0 float NORM SPEED 50 0 float FAST SPEED 100 0 16 float STOP 0 0 void main poke 0x7000 0x03 start_process read_sensors start_process find_IRQ start_process avoid_obstacles start process find lite 17
6. T MOTOR NORM SPEED motor RIGHT MOTOR STOP void go_forward_left motor RIGHT MOTOR NORM SPEED 15 0 motor LEFT MOTOR STOP void go_fast motor RIGHT_MOTOR FAST_SPEED motor LEFT MOTOR FAST SPEFD 20 0 void go_back motor RIGHT_MOTOR 1 0 SLOW_SPEED 2 0 motor LEFT_MOTOR 1 0 SLOW_SPEED 2 0 4 0 void go_back_left motor LEFT_MOTOR 1 0 SLOW_SPEED motor RIGHT_MOTOR STOP void go back right i motor RIGHT MOTOR 1 0 SLOW SPEED motor LEFT MOTOR STOP 13 void go_around_right motor RIGHT_MOTOR 1 0 SLOW_SPEED 5 0 motor LEFT_MOTOR SLOW_SPEED 4 0 void go_around_left motor RIGHT_MOTOR SLOW_SPEED 5 0 motor LEFT_MOTOR 1 0 SLOW_SPEED 5 0 void wait int milli_seconds long timer_a timer_a mseconds long milli_seconds while timer_a gt mseconds defer void read_sensors while 1 IR_LEFT analog 6 IR_RIGHT analog 7 TOUCH peek 0x1000 amp 0x03 LEFT analog 1 RIGHT analog 0 CENTER analog 2 MAGNET analog 4 BEACON analog 3 LIGHT analog 5 defer void avoid obstacles while 1 if IR LEFT gt THRESHOLD2 amp amp IR RIGHT lt THRESHOLD II LEFT gt 65 amp amp RIGHT lt 55 go back right sleep 2 else if IR_RIGHT gt THRESHOLD 1 amp amp IR LEFT lt THRESHOLD2 II LEFT lt 50 amp amp RIGHT gt 50 go back left sleep 2 14 else if
7. asoft ME11 Kit MIL lab h aa 53 00 4 Motorola EVBU M68HC11 E9 board 68 00 tax 72 20 5 3 Photodiodes CSUMIUED isc kk kk 12 00 6 Magnetic sensor estimated 10 00 Te Miscellany OSS A y kh da nn ko d ka esl Ekbes z n 37 80 5 Total ostimated es ont n ende A 250 00 Conclusion Mine sweeper is supported to perform object avoidance behavior detecting IR turning off IR emitter and finding the way back to its starting location Replacing the traditional CdS sensor with Photodiode built in amplifier improves the red and white color detection rate and flashing light The two little light bulbs that required 1 2V and 220mA each drain lots of current So I have to use another battery pack to prevent some crazy behaviors 10 Documentation F G Martin The 6 270 Robots Builder s Guide 1992 Motorola MC68HC11 EVBU User s Manual 1992 Assembly Manual Mekatronix ME11 Expansion Board for the MC68HC11 EVBU 1997 Keith L Doty Talrik Junior Assembly Manual 1996 11 APPENDIXES Rudimentary obstacle avoidance using 2 front mounted IR sensors and when detecting a red line Find IR at corners By Nick Nguyen 6 Oct 1997 void stop_go motor RIGHT_MOTOR STOP motor LEFT_MOTOR STOP void go_forward motor RIGHT_MOTOR NORM_SPEED motor LEFT_MOTOR NORM_SPEED 15 5 void go_forward_right motor LEF
8. orm A TJ platform which is produced by Novasoft is used for this project because of it s small shape and light weight Those reasons will help the robot avoid obstacles easier and save energy The platform was modified to fix the EVBU board So it still looks compact even with EVBU and ME11 boards on Actuation 1 Battery Power two 6 AA NiCd battery packs 7 2 V LM2930 regulated the voltage down to 5 V to supply to MCU and ICs 2 Motor Two Aristo MS410 servos are controlled by SN754410NE 1A max Sensors The Mine Sweeper employs 4 types of sensors 1 IR sensors proximity and long range 2 Bump switches 3 Magnetic field sensor 4 Photodiodes red color and flash light detection Three hacked Sharp GP1U58Y infrared sensors are used as the IR proximity detector and IR long range detector The IR proximity detector receives IR which reflects from objects in its path and IR long range detector beacon detector looks for IR from the mines The analog output is about 1 5 V 2 5 V The processor A D converter provides digital outputs in the range 86 to 131 about 5 5 bits of precision Bump switches detect anything else that IR proximity detector can not see or in case the robot backs up into the wall The digital outputs are 0 normally open and 255 close when hitting a obstacle IMT magnetic field detector will help the robot avoid the magnetic mines in its path Taking the advance of LED array to decide the threshold
9. ss than 1000s 14 kHz Operating Time 20 minutes estimated at full charged Size 7 in diameter 6 in height e Power Supply 2 packs of 6 AA NiCd batteries e Require a PC DOS and IC with a serial port and a RS232 serial cable e Detect red and white color using photodiodes Integrated System The Mine Sweeper uses a Motorola M68HC11 E9 EVBU micro controller board which is easy to program and the price is low Also it can do many different functions such as Real Time Interrupt RTI Input Compare IC Output Compare OC Pulse Accumulator PA and Analog to Digital Converter A D A MEI1 expansion board produced by Novasoft is added to the EVBU The ME11 is designed especially for robotic applications Its features include 32Kbytes of RAM 8 bits of digital output capable of driving a total of 75ma continuous current A single output can drive as much as 35ma of continuous current 4 digital input and 4 digital output enables controlled by the R W line and E clock of the MC68HC11 processor An H bridge motor driver with thermal shutoff that can drive two small DC motors with maximum sustained current of 1A through each motor A stable crystal driven 40Khz clock to modulate IR and sonar A 16 pin DIP socket for mounting resistors or other discrete components in series with the digital outputs A 60 pin header providing direct mating to a connector added to the EVBU board Mobile Platf
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