LFR

LINE FOLLOWING ROBOT: 

LINE FOLLOWING ROBOT BY AMITHASH E. PRASAD (1GA01EC002)

What is a robot?: 

What is a robot? Robots are machines which do a task which would otherwise be done by human labor. Robots may or may not possesses intelligence.

TYPES OF ROBOTIC INTELLIGENCE: 

TYPES OF ROBOTIC INTELLIGENCE Expert systems Neural Systems

THE LINE FOLLOWING ROBOT (LFR): 

THE LINE FOLLOWING ROBOT (LFR)

REQUIREMENT OF THE LFR: 

REQUIREMENT OF THE LFR The robot must be capable of following a line. It should be capable of taking various degrees of turns It must be prepared of a situation that it runs into a territory which has no line to follow. (Barren land syndrome) The robot must also be capable of following a line even if it has breaks. The robot must be insensitive to environmental factors such as lighting and noise. It must allow calibration of the line’s darkness threshold. Scalability must be a primary concern in the design. The color of the line must not be a factor as long as it is darker than the surroundings.

THE BLOCK DIAGRAM: 

THE BLOCK DIAGRAM PIC 16F873 Microcontroller H - Bridge DC Motor Control Left Motor Right Motor Clock 4 MHz Main Power Supply Motor Power Supply HEX Inverter Sensor Array Analog Comparators Threshold Voltage Priority Encoder NOR Gate

THE DIFFERENTIAL STEERING SYSTEM : 

THE DIFFERENTIAL STEERING SYSTEM

MOTOR CONTROL : 

MOTOR CONTROL

H-BRIDGE MOTOR CONTROL : 

H-BRIDGE MOTOR CONTROL

H-BRIDGE MOTOR CONTROL: 

H-BRIDGE MOTOR CONTROL

H-BRIDGE MOTOR CONTROL: 

H-BRIDGE MOTOR CONTROL

H-BRIDGE USING TRANSISTORS: 

H-BRIDGE USING TRANSISTORS

H-BRIDGE WITH SPEED CONTROL: 

H-BRIDGE WITH SPEED CONTROL

PWM SPEED CONTROL: 

PWM SPEED CONTROL

THE PIC MICRO CONTROLLER (PIC 16F873): 

THE PIC MICRO CONTROLLER (PIC 16F873) RISC ARCHETECTURE 1 WORD INSTRUCTION LENGTH FIXED INSTRUCTION EXICUTION TIME 3 PORTS (A, B & C) 2 CCP (CAPTURE, COMPARE & PWM) MODULES 192 BYTES DATA RAM & 128 BYTES OF EEPROM DATA MEMORY UPTO 13 INTERRUPT SOURCES 3 TIMERS Power saving SLEEP mode A/D CONVERTOR

PICMICRO CCP MODULES IN PWM MODE: 

PICMICRO CCP MODULES IN PWM MODE

THE SCHEMATIC: 

THE SCHEMATIC

HARDWARE DESCRIPTION: 

HARDWARE DESCRIPTION

THE POWER SUPPLY: 

THE POWER SUPPLY

MOTORS: 

MOTORS Motor speed = 2400 rpm @ 6v Using gears the speed is reduced to 30 rpm @ 6v. The motors are run at 12v, so an effective speed of 60 rpm is achieved, with a considerable increase in torque.

THE H-BRIDGE CONTROL HARDWARE: 

THE H-BRIDGE CONTROL HARDWARE

STATE TABLE: 

STATE TABLE IN1 IN2 IN3 IN4 OPERATION 1 0 1 0 BOTH MOTORS FORWARD (MOVE FORWARD) 0 1 0 1 BOTH MOTORS BACKWARD (MOVE BACKWARD) 1 0 0 1 RIGHT MOTOR BACKWARD LEFT MOTOR FORWARD (TURN RIGHT) 0 1 1 0 RIGHT MOTOR FORWARD LEFT MOTOR BACKWARD (TURN LEFT)

THE IR SENSORS: 

THE IR SENSORS Interrupter sensor modified to be a reflective sensor ~950nm wavelength Lens fitted to emitter and detector of focal length of 4mm

SENSOR CIRCUIT: 

SENSOR CIRCUIT

SENSOR ARRAY: 

SENSOR ARRAY MINIMUM DISTANCE BETWEEN SENSORS IS 1cm

THE PRIORITY ENCODER: 

THE PRIORITY ENCODER

THE NO SURFACE LOGIC: 

THE NO SURFACE LOGIC

INPUTS TO THE MICROCONTROLLER: 

INPUTS TO THE MICROCONTROLLER NS GS A2 A1 A0 STATE IN ACTION 1 X X X X No surface is detected Stop the motors 0 1 X X X No line is detected Execute the no line code (specially designed algorithm) 0 0 0 0 0 A detects the line Sharp turn left 0 0 0 0 1 B detects the line Sharp turn right 0 0 0 1 0 C detects the line Turn left 0 0 0 1 1 D detects the line Turn right 0 0 1 0 0 E detects the line Move left 0 0 1 0 1 F detects the line Move right 0 0 1 1 0 G detects the line Go straight 0 0 1 1 1 Forbidden state Software reset the processor

PROCESSES INVOLVED: 

PROCESSES INVOLVED

LINE FIND MODE: 

LINE FIND MODE

FLOW CHART: 

FLOW CHART

APPLICATIONS: 

APPLICATIONS Industrial automated equipment carriers Automated cars. Tour guides in museums and other similar applications. Second wave robotic reconnaissance operations.

LIMITATIONS: 

LIMITATIONS Choice of line is made in the hardware abstraction and cannot be changed by software. Calibration is difficult, and it is not easy to set a perfect value. The steering mechanism is not easily implemented in huge vehicles and impossible for non-electric vehicles (petrol powered). Few curves are not made efficiently, and must be avoided.

…LIMITATIONS: 

…LIMITATIONS Lack of a four wheel drive, makes it not suitable for a rough terrain. Use of IR even though solves a lot of problems pertaining to interference, makes it hard to debug a faulty sensor. Lack of speed control makes the robot unstable at times.

FUTURE SCOPE: 

FUTURE SCOPE Software control of the line type (dark or light) to make automatic detection possible. “Obstacle detecting sensors” to avoid physical obstacles and continue on the line. Distance sensing and position logging & transmission.

RESULT AND CONCLUSION: 

RESULT AND CONCLUSION The robot follows a line as demonstrated. It effectively overcomes problems such as “barren land syndrome” and line breaks. The hardware and software works as designed.

BIBLIOGRAPHY: 

BIBLIOGRAPHY Programming and Customizing the PIC microcontroller by Myke Predko PICmicro Mid-Range MCU Family Reference Manual by MICROCHIP PIC Robotics, A beginner’s guide to robotics projects using the PICmicro by John Iovine

…BIBLIOGRAPHY: 

…BIBLIOGRAPHY Websites referred… The Seattle Robotics Society Encoder library of robotics articles Dallas Personal Robotics Group. Most of these tutorials and articles were referred. Go Robotics.NET, this page has many useful links to robotics articles.

…BIBLIOGRAPHY: 

…BIBLIOGRAPHY Carnegie Mellon Robotics Club. This is the links page with lots of useful resources This page is called the “Micro-mouse Handbook” and an excellent tutorial for small scale robotics. This is the main website of microchip. Thousands of application notes, tutorials & manuals can be found here.

Thank you: 

Thank you