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ECE/ME 491/2 Group 4 Winter 2009

ECE/ME 491/2 Group 4 Winter 2009. Benjamin Chen Suhail Gul Wai-Sze Lok Rob Merkle Brian Shaw Renee Soenen. Meet the All-Star Team!. Benjamin Chen Electrical Engineer. Suhail Gul Electrical Engineer. Brian Shaw Computer Engineer. Wai-Sze Lok Mechanical Engineer.

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ECE/ME 491/2 Group 4 Winter 2009

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  1. ECE/ME 491/2 Group 4Winter 2009 Benjamin Chen SuhailGul Wai-SzeLok Rob Merkle Brian Shaw Renee Soenen

  2. Meet the All-Star Team! Benjamin ChenElectrical Engineer SuhailGulElectrical Engineer Brian ShawComputer Engineer Wai-SzeLokMechanical Engineer Renee Soenen Mechanical Engineer Rob MerkleMechanical Engineer

  3. Meet JOE-BOT! JOE-BOT IS COMING FOR US! RAWRR!

  4. DC Motor vs Modified Servo • DC Motor: • Energy efficient • Powerful • Modified Servo: • Excellent control of speed • Sufficient torque and speed in a compact unit • Internally geared • Don’t need H-bridges

  5. Digital Servo • Problem: • Kept rotating slowly with no pulse input • Possible Reason: • Internal mechanical issue • Servos and board may not compatible

  6. DC Motor Problem: • Exceeded size • Less space • Solution: • Modified original chassis by machining notches • Flip the chassis, so the motors were on the underside

  7. Design Changed • Machining notches into the sides • Flip chassis provide more space • 3 platforms instead of 2

  8. Video of 90° turn MOVEMENT Multi – directional wheel called a Transwheel Two motors drive the set of wheels that are 180° apart 90° degree turns switching power to other set of wheels Provides versatility of movement with no steering

  9. Video of 45° approach across ramp MOVEMENT ISSUES Driving wheels lift off the ground at bottom of ramps Resolve by driving up the ramp at 45° New FEA due to different torque on the motor shaft

  10. Y FINITE ELEMENT ANALYSIS X N Ff 15° 10.545° ∑Fx = 0 = Ff-Wx Free Body Diagram – 3 Dimensional Torque ∑Fy = 0 = N-Wy ∑M = 0 = Ff*r - T Wx Wy Wsin(10.545°)*r=Wx*r=T W

  11. FEA - MODEL Custom Shaft Assembly W T Nylon Adapter Motor Shaft “Universal” Hub

  12. Fire Extinguisher • Pump • Reservoir • Check-valve • Nozzle

  13. Fire Extinguisher • Operating at 12 volts • 0.54 GPM • Mounted at 20 cm • Turned on with a relay switch

  14. Fire Extinguisher • VIDEO OF ROBOT EXTINGUISHING FLAME

  15. Cost Analysis Material Costs Labor Costs

  16. Electronic Platform Selection • Motorola HCS12 based EVBplusMiniDragon+ • Easiest to program for (familiarity) • Enough I/O connectivity • Low enough overall power usage

  17. Stages of development on the design • Type of Platform and wheel vs. track • Use of servos vs. motors • Different types of sensors proposed to be used • Navigational Algorithm.

  18. Parts and Components • Servo mountings and turrets holder • 360⁰ Turret • Aluminum base shaping and cutting and supports • Mounts for motors. • Motor Gears.

  19. Circuits and Wiring • H Bridge. • Voltage Regulator.

  20. Circuits and Wiring • Pump Switch Circuit. • Wiring for Power Sources and sensors

  21. Testing and Interfacing the Sensors • Programming servos and setbacks. • Motor Control . • Sensors Testing. • Digital IR Sensors. • Analog IR Sensor. • Compass Module. • TPA 81. • Sonar.

  22. Basic Movement • 4 Omni-Wheels, two wheels each side of the robot. • Each wheel can be turned independently of the others. • The capability of independent wheel control combined with the placement of the wheels allows for versatile movement controls. • Very fast zero-radius turning. • Vectored movements, e.g. sideways and 45° diagonal movement. Navigation

  23. Navigation Ramps • Ramps have posed a formidable challenge for Joe-bot. Due to the wheel placements, it cannot drive straight onto a ramp. This is both a curse and a blessing. • It is possible for Joe-bot to detect a ramp simply by checking the long distance rangefinder. If it has detected that it has not moved and the distance is more than a few centimeters, then it is in front of a ramp. • The Joe-bot can then turn 45° and travel at that angle to get on the ramp and over it. Obstacles • Obstacles in the rooms are still a challenge. The sensor array as it stands has a tough time discovering obstacles.

  24. Navigation Hallway Travel • Joe-bot has three pairs of short range IR sensors on the front and sides. Also, it has a long range sonar rangefinder. • It can currently navigate the hallway by keeping track of whether or not walls are sensed on either side by the IRs and also using the rangefinder. Room Mode • When we approach a room, Room Mode becomes active. This is a special procedure for detecting the candle, putting it out and exiting the room we entered. • The room is scanned either once or twice; if we detect extra heat (the candle), the second sweep searches for obstacles. • We then move toward the candle and extinguish it.

  25. Any questions?

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