Vehicle Following System

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Vehicle FollowingSystem
United Arab Emirates University College of
Engineering Graduation Project II

Project Advisor Dr. Hassan Noura Project
Co-ordinator Dr. Qurban Ali

• Mohammad Saad Laghari 200235906
• Saeed Aqeel Saeed 200305445
• Badr Al-Salmy 200235572
• Marwan Essa Bastaki 200540932

Second Semester 2007/2008
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Contents

• Introduction
• Background Theory
• Mathematical Modeling
• Digital Control
• Sensor
• Microcontroller
• Motor Switching Function
• System Structure and Final Design
• Gantt Chart for GPI
• Gantt Chart for GPII
• Conclusion

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Introduction
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• Make the 2nd car follow the 1st car
• 1st car ? remote controlled
• 2nd car ? autonomous motion by
• keeping the distance constant
• using a digital control system
• Safety Factor
• Environmental Factor

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• The team objective is to design this system and
  develop the controller that allows achieving the
  vehicle following system
• Necessary instruments to complete the project
  are
• Sensors
• Micro-controller
• H-bridges
• Mosfets
• Circuit Components
• Etc.

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• The team work includes
• Design construction
• Instrumentation
• Computer modeling analysis
• Implementation and control
• Testing experimental investigation

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• Both cars are to communicate via a communication
  system (transmitter receiver) set
• A control system has to be installed on the
  follower car
• This will allow it to start into motion when the
  first car does and stop when the first car stops,
  keeping a predetermined distance
• The control system basically includes some
  computer software which translates the logic of
  motion of the follower car
• This software is to be installed onto an
  appropriate micro controller chip

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Applications and Uses

• Decrease man-power (lower cost and time, more
  work)
• Pesticide Control (Farming)
• Transportation
• Manufacturing
• Carriages
• Automated High-ways

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Background Theory
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Cars

• Speed
• Deceleration
• Weight
• Size
• Circuitry of Motor
• Price

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Communication

• Ultra-sonic
• Only frequency around 40KHz is detected
• Distance increases, Voltage decreases
• (vice-versa)

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Microcontroller Motor

• The peak voltage received from receiver is
  received by micro-controller
• Micro-controller determines if the voltage is
  nominal (set voltage) using simple
  microprogramming codes
• Micro-controller then sends a signal to the
  H-bridges
• The H-bridges then sends the signals to the
  powere MOSFETs, which in turn send the signals to
  the motors

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Mathematical Modeling
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• The 2nd Cars body coordinates

Define
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This model is not complete, since the state space
should include input voltages (or currents).
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J Mass moment of inertia kt Torque Constant B
Friction of Motor
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Digital Control
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Main Parts of a Digital Controller

• A/D conversion
• D/A conversion
• A program

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High Proportional Gain
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Low Proportional Gain
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Reasonable Proportional Gain
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PD Controller Response
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PID Controller Response
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Car Position Block Diagram
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Car Direction Block Diagram
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Sensors
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Ultra-sonic Sensors

• Systems typically use a transducer which
  generates sound waves in the ultrasonic range,
  above 20,000 hertz,
• by turning electrical energy into sound,
• then upon receiving the echo
• turn the sound waves into electrical energy which
  can be measured and displayed

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Transducer

• An ultrasonic transducer is a device that
  converts energy into ultrasound, or sound waves
  above the normal range of human hearing
• Piezoelectric crystals
• Changing size when a voltage is applied
• Applying an alternating voltage (AC) across them
  causes them to oscillate at very high frequencies
• Thus producing very high frequency sound waves

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Detectors

• Since piezoelectric crystals generate a voltage
  when force is applied to them, the same crystal
  can be used as an ultrasonic detector
• Since the detector will only be used to detect
  ultrasonic waves, the design is such a way that
  all other waves (or most of them) are eliminated

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Receiver
Transmitter
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• Frequency 40 KHz
• Input Voltage 14Vpp

Distance (cm) Receiver output (V)
50 0.646
37.5 0.91
25 1.23
12.5 1.4
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CAR 1
CAR 2
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15 cm
5 cm
1.2 mm
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Logic

• Angle Sensors
• Programming
• Both increase or both decrease
• Right sensor increases, Left decreases
• car turns right
• Left sensor increases, Right decreases
• car turns left

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Microcontroller
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PIC16F877

• InputH and InputL
• 0-0.5V
• 2.0-5.5V
• OutputH and OutputL
• 0-0.7V
• 4.2-5V

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PIC16F877
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PIC Programming

• Ports (I/O)
• TRISA 0x00000000
• Bit 0 output, Bit 1 input
• (TRISA, TRISB, TRISC,
• TRISD, TRISE)
• ADCON1 00000000
• (Set PORTA to Analog)

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ADC

• Voltage range VCC (5V)
• 0-5V input 8 bits --gt 0-255 or 0-64k
• DEFINE ADC_BITS 8
• ADCIN 0, measurement
• DEFINE ADC_SAMPLEUS X
• (Sampling time in us)

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Reset Circuit
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External Oscillator
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Variable Speed

• Sensor Levels
• Motor Input
• Microcontroller Output

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PWM - Duty Cycle

• Duty cycle

• HPwm 1, control, 15000

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The Code
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Motor Switching Function
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High and Low Side Driver
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• Function
• Amplification
• Isolation
• Features
• Fully operational to 600V.
• Matched propagation delay for both channels.
• Noise immunity.
• Outputs in phase with inputs.

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DC Motor-Driver H-Bridge Circuit
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A B C D State
0 0 0 0 Off
0 0 0 1 Off
0 0 1 0 Off
0 0 1 1 Brake
0 1 0 0 Off
0 1 0 1 SHORT
0 1 1 0 Reverse
0 1 1 1 SHORT
A B C D State
1 0 0 0 Off
1 0 0 1 Forward
1 0 1 0 SHORT
1 0 1 1 SHORT
1 1 0 0 Brake
1 1 0 1 SHORT
1 1 1 0 SHORT
1 1 1 1 SHORT
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System Structure and Final Design
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• AC Signal Generator
• Ultra-Sonic Transmitter-Receiver Set
• Bridge Rectifier Amplifier
• PIC16F877 Microcontroller
• Driver Chip MOSFET H-Bridge
• Voltage Regulator

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AC Signal Generator
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Bridge Rectifier Amplifier
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PIC16F877 Microcontroller
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Driver Chip MOSFET H-Bridge
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Voltage Regulator
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Final Circuit of the Second Car
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Final Circuit of the First Car
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Final Design Side View
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Gantt Chart for GPI
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Gantt Chart for GPII
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Conclusion
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• Project was successful
• Information from courses
• Digital Control Systems
• Programming Courses (Java and C)
• Electronics
• Power Electronics

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• Hardships Faced
• Sensors
• H-Bridge
• Microcontroller

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Thank You For ListeningQUESTIONS?