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Automated Bridge Scour Inspection

Automated Bridge Scour Inspection. FSU/FAMU College of Engineering Team 7 Detailed Design Review and Test Plan 2/8/2011. -Vertical DC motor -Motor Controller -2 SLA Batteries .  Vertical Guide Rail. Circular Rail . -MicroController -Sonar -NiMH Battery -Tilt Servo -Circular DC

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Automated Bridge Scour Inspection

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  1. Automated Bridge Scour Inspection FSU/FAMU College of Engineering Team 7 Detailed Design Review and Test Plan 2/8/2011

  2. -Vertical DC motor -Motor Controller -2 SLA Batteries   Vertical Guide Rail Circular Rail  -MicroController -Sonar -NiMH Battery -Tilt Servo -Circular DC Motor 

  3. Vertical Motion Drive Design Updates: • Revised gearhead selection • Previously a 28:1 Ratio • Now a 26:1 Ratio • Trade-off: Availability vs. Over-specification • Comparable Performance: • Slightly slower ascent • Moderately higher percentage of motor output ability

  4. Vertical Motion Drive Design Updates: • Revised encoder selection • Previously using Magneto-Resistant (MR) • Now using Optical • Trade-off: Availability vs. Cost • Comparable Performance: • 500 CPR vs. 512 CPR

  5. Vertical Motion Drive Mechanical Test Plan: • Part One: • Confirm rated no-load output velocity • Measure angular velocity with tachymeter • Part Two: • Prior to full integration, simulated mass lift • Confirm loaded output torque ability • Protect components prior to integrated test

  6. Circular Motion Drive Design Updates: • Unchanged Motor/Encoder/Gearhead • Revised drive-surface interaction • Previously: Geared drive-surface on guiderail • Now: High-friction contact drive • Trade-off: Manufacturability vs. Precision

  7. Circular Motion Drive Mechanical Test Plan: • Part One: • Confirm rated no-load output velocity • Measure angular velocity with tachymeter • Part Two: • Prior to full integration, full-speed revolution • Confirm loaded output torque and velocity • Protect components prior to integrated test

  8. SONAR Tilt Servo Drive Design Updates: • Unchanged Servo Motor selection • Low risk of failure under load • Focus on adequate positioning

  9. SONAR Tilt Servo Drive Mechanical Test Plan: • Prior to SONAR integration • Simulate moment arm to represent transducer • Demonstrate loaded angular range of motion • Confirm inspection range capability

  10. Vertical Motion Updates • Material • Aluminum vs Stainless • Rollers • Drivers • Idlers • Bearings • Size Constraint

  11. Bearings and Rollers

  12. Circumferential Motion Updates • Material • Design • Driver • Idlers • Expectations

  13. Circular Guide Rail • Changes • Size and Shape • Material • Connection • Manufacturing • Ideas • Simplify

  14. Testing • Vertical and Circumferential Motion • Degrees of Freedom • Waterproofing • Step by Step

  15. Updated Plan- Use two Battery sources Higher-Power →Motor Controller,DC motors Lower-Power →Microcontroller,servo, sonar Electrical Design

  16. Higher-Power Design • Battery →Sealed Lead Acid Battery (SLA) - Most likely will be 12 Volt, 3 Ahr SLAs - Will need 2 of these to make 24V in series • Fuse and Switch on positive battery wire to motor controller

  17. Why use 2 -12 Volt 3Ahr Battery? The Vert. DC motor → 24V ~3A continous Running for < 3 minutes for a final test run. The Circular motor → 12V ~300mA cont. Running for < 10 minutes for a final test run. High-Power Design

  18. Estimate Current Draw per Test

  19. Lower-Power Design • Battery → NiMH • MicroController needs 5V ~500mA ..Max 2A • Voltage regulator to get constant 5V • May need heat sink • Power to servo and sonar sensor as well • Battery size depends on final servo, sonar choice. Neither should be current demanding components

  20. $88 4500 mAh battery 5V output 1.5A current delivery powers a BeagleBoard for at least 6.5 hrs on/off switch Possible option for battery source, mounts below the microcontroller, space saver The Beaglejuice

  21. Microcontroller

  22. Expansion Board Zippy2 • I2C 1.8v to 5v • 2nd RS-232 port • 2nd SD slot • Ethernet

  23. Programming – Autonomous Movement Motor Controller & Motors Coding • Sabertooth: In simplified Serial Mode • RS-232 port • Using single 8byte commands to control speed & direction of motors • Each motor 7bits of Resolution • Motor1: 1-127 • Motor2: 128-255

  24. Programming – Autonomous Movement Encoders & Servo Coding • I2C interface • Encoders: Counting the leading & falling edge to determine distances • Servo: PWM (Pulse Width Modulation)

  25. Testing Autonomous Movement Program • Program Simulations: I/O Signals • MCU & Oscilloscope: PWM • - Pulse Widths approx.: 1ms to 2ms • - Period: 10ms to 2ms • MCU & Signal Generator: Simulate encoder input (Square Waves)

  26. SONAR – Control Test • Humminbird HDR 650 • Transducer/Display combo • 2ft. – 600ft. • Verify data accuracy from other transducers • ~ 1.2in. Resolution • 200kHz • Strictly handheld; will not be connected to MCU

  27. SONAR Transducer • Furuno USA • 235 kHz • 7 degrees • 0.04m – 100m • NMEA 0183 – ASCII serial communications • Sentence structure: DDBT, DDPT

  28. NMEA 0183 Sentence Structure • 8 bits • 4800bps • Checksum = hexadecimal; XOR of all char between $ and *

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