Robotic%20Navigation%20Distance%20Control%20Platform

1
Robotic Navigation Distance Control Platform

• By
• Scott Sendra
• Advisors
• Dr. Donald R. Schertz
• Dr. Aleksander Malinowski
• April 29, 2004

2
Overview

• Objective
• Functional Description
• System Block Diagrams
• Lab Work
• Results
• Future Development and Research
• Equipment / Part List
• Sources
• Questions

3
Objective

• Design and Build a Robotic Platform
• Maintain a fixed safety distance
• Fixed steering
• Small and economical system
• Applications
• Robotics
• Slow speed moving vehicles
• Automotive

4
Functional Description

• Modes of Operation
• System I/O
• System Diagrams

5
Modes of Operation

• Fixed Navigation Mode
• User enters fixed safety distance in feet
• User enters User or Auto Out of Range Mode
• User presses activation button
• Increment / Decrement Mode
• User is able to (increment / decrement) motor
  speed by one unit manually

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Modes of Operation

• User Out of Range Mode
• Followed object is out of range of sensor
• Robotic platform stops
• Out of Range displayed on LCD
• User reactivates navigation controls by pressing
  0
• Following displayed on LCD
• Auto Out of Range Mode
• EMAC reactivates navigation controls when object
  is detected

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Modes of Operation

• Stop / Reload Mode
• User is able to (stop / reload) motor speed
  manually
• Navigation Control Mode
• User is able control Navigation Mode

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System Inputs to EMAC

• User Input
• Keypad
• Sensor Input
• Ultrasonic sensors
• 1 sensor for distance control

9
System Outputs from EMAC

• LCD Display
• Current mode of operation
• User required input information
• Robotic Platform Motor
• Robotic Platform Steering
• Trigger Pulse for Sensor

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System Sensor Diagram
Robotic Platform (R/C Car)
Moving Object (Similar size to robotic
platform)
Distance Sensor
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System Block Diagrams

• Hardware
• Subsystem Function
• I/O of Subsystem
• Software
• Modes of Operation Flowcharts

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Sensor Subsystem

• SRF04 Ultrasonic Pulse Sensor
• Sensor Input Signal
• Trigger Pulse of 1.5 ms
• Sensor Output Signals
• Output signal related to distance
• PWM at 33 Hz

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Electric Motor Subsystem

• ESC and Electric Motor
• Input signal
• PWM signal from 1.0 ms to 1.7 ms positive pulse
  width at 33 Hz
• Output speed
• Motors shaft speed varies
• Full forward speed with 1.7 ms pulse width
• Stop with 1.0 ms pulse width

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Steering Subsystem

• Input signal
• PWM signal from 1.1 ms to 1.9 ms positive pulse
  width at 33 Hz with 1.5 ms as neutral
• Output
• Rotational servo horn to translational movement
  of steering rod

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Hardware Subsystem Block Diagram
EMAC Microcontroller
Power to Drive Wheels on R/C Car
Robotic Platform Motor Subsystem
PWM Signal
PWM Signal
Distance Control Sensor Subsystem
Robotic Platform Steering Subsystem
Translates Steering Rod
Trigger Pulse
PWM Signal
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Main Software Flowchart
EMAC Initialization
Keypad Initialization
LCD Initialization
Fixed Steering Control
Control 0
Fixed Distance Display Prompt Enter 1-9 feet
Keypad User enters fixed distance
Out of Range Mode Display Prompt Press 1 for
User Press 2 for Auto
Keypad User Enters Out of Range Mode
Display Prompt Press 0 to Activate
Keypad User Enters 0
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Main Software Flowchart(Fixed Navigation Mode)
Check Control Variable
1
0
No
Check if signal from sensor
Check Keypad
No
Yes
Enter User/Auto Out of Range Mode
Call Software Mode Pressed
Yes
Measure gt Desired
Measure lt Desired
Fixed Distance Control
Measure Desired
Increment Motor Speed
Decrement Motor Speed
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User/Auto Flowchart
User/Auto Out of Range Mode
Stop Electric Motor
Display Out of Range
User Out of Range Mode
Auto Out of Range Mode
Display Wait for object
Display Press 0 to Activate
Display Following
Waits for User to Press 0
Return
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Increment / Decrement Motor Speed Flowcharts
Keypad User Presses Increment Motor Speed Button
C
Keypad User Presses Decrement Motor Speed Button
E
Display Prompt Manual Inc Speed Press 0 to
Activate
Display Prompt Manual Dec Speed Press 0 to
Activate
Call IncMotorSpeed ()
Call DecMotorSpeed ()
Return
Return
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Stop / Reload Flowcharts
Keypad User Presses Stop Button B
Keypad User Presses Reload Motor Speed Button D
Save Current Motor Speed
Display Prompt Reload Last Speed Press 0 to
Activate
Stop Electric Motor
Loads Last Motor Speed
Display Prompt Manual Stop Press 0 to Activate
Return
Return
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Navigation Control
Keypad User Presses Control Button 0
Toggle Control Bit
Check Control Variable
1
0
Stop Electric Motor
Display Following
Display Deactivated
Return
Return
22
Lab Work

• Ultrasonic trigger pulse and servo input signals
  with 1.5 ms at 33 Hz being neutral using Timer 2
• ESC reprogrammed
• Reprogrammed 1.0 ms stop
• 1.7 ms full forward
• Ultrasonic PWM signal measurements using
  interrupts
• Output PWM signal using Timer 2 on EMAC to
  control motor speed

23
Lab Work

• Control Strategy
• Current distance is smaller than user-defined
  distance
• -Decrease PWM signal to motor by fixed number
• Current distance is larger than user-defined
  distance
• -Increase PWM signal to motor by fixed number

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Lab WorkCircuit Diagram
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Results

• All software modes are complete
• EMAC on the robotic platform triggers ultrasonic
  sensor and measures PWM signal from sensor
• EMAC increases or decreases motor speed
• Robotic platform maintains the entered safety
  distance from object

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Results
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Results
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Future Development and Research

• Model and determine transfer function of robotic
  platform
• Implement a better control strategy
• Incorporate steering of platform using more
  sensors
• Using fuzzy logic steering to allow platform to
  steer non-linearly around corners

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Equipment and Parts List

• Hitec HS-303 Servo
• Kyosho Hoppin Mad RTR R/C Car
• Team Novak Rooster electronic speed controller
• HP 8011A Pulse Generator
• SRF04 Ultrasonic pulse sensors
• 80535 EMAC Microcontroller

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Sources

• http//www.teamnovak.com/Download/acrobat/rooster_
  superr.pdf
• http//www.hitecrcd.com/Servos/DiscontinuedServos/
  HS303.pdf
• http//www.robot-electronics.co.uk/shop/Ultrasonic
  _Ranger_SRF041999.htm
• http//www.i-car.com/html_pages/about_icar/current
  _events_news/advantage/advantage_online_archives/2
  004/021604.html
• http//www.gavrila.net/Computer_Vision/Smart_Vehic
  les/Media_Coverage/spectrum.pdf
• http//www.ece.msstate.edu/classes/design/ece4532/
  2003_spring/cruise_control/

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QUESTIONS?Project Website
http//cegt201.bradley.edu/projects/proj2004/distc
ont/