1. Battery Buggy ’11 Dennis Papesh (papeshdr@holyangels. cc) Bro
Battery Buggy ’11 Dennis Papesh Bro. Nigel National Event Supervisors

2. Disclaimer???
This presentation was prepared using draft rules. There may be some changes in the final copy of the rules. The rules which will be in your Coaches Manual and Student Manuals will be the official rules.

3. Object: A battery powered vehicle travels a specific distance as quickly as possible around an object and stop as close as possible to the Finish Dot.

4. What???
Yes, this year, the vehicle must not only get to the finish as quickly as possible, it must go around an object to do so. (It has to deliberately do the arc that some did unintentionally last year.)

5. For several years…
BTW, a good Coaches aid is You Tube, Google Video, etc. Just type “Electric Vehicle Science Olympiad” and search
Just like some of these:
For pictures, go to the SO Student center:

6. But that was changed last year with the addition of speed!!
YouTube - Battery Buggy v4 Practice: 9m

7. have a wheelbase of 30.0 +/-2.0 cm
The vehicle must:
be propelled ONLY by energy from a maximum of 4 commercially available batteries (each rated at 1.5 V or less) or one battery pack (rated at 4.8 V or less)
No other electrical energy is permitted
have a wheelbase of /-2.0 cm
Midpoints of front and rear axle
be started by actuating a switch of some sort with a pencil or similar object
They CANNOT hold it when doing so!
Must be a vertical action
come to a complete stop without any outside assistance.
But braking system may NOT contact the floor.

8. Any “black boxes” should be easily opened to allow inspection.
aligning devices may be used which do NOT have to be permanently attached in a fixed position
have a fixed, pointed object extending beyond ALL other parts of the vehicle and within 1 cm of the track’s surface to be used as the reference point for all distance measurements.
The most common item which puts the vehicle in jeopardy of being lower tiered
NOT have any electronic components at all. Only the electrical items listed in the rules may be used.
Any “black boxes” should be easily opened to allow inspection.

9. Testing: To achieve the maximum score, the vehicle should be thoroughly tested.
It should
be adjustable to travel 8 meters for regional, from 6 to10 meters for state (in 1.00 meter intervals), and 6 to 10 meters for national tournaments (in 0.50 meter intervals)
come to a complete stop with the vehicle’s fixed, pointed object (hereafter “fixed point”) as near as possible to the Finish Dot

10. The Track
8.0 meters . .
The Start Dot and the Finish Dot are interchangeable to accommodate different venues and the direction of arc of the vehicle.

11. The Track The track will: be on a smooth, level, and hard surface
have Starting Dot, a Finish Dot, and a 5 gallon bucket placed directly in the midpoint of the course.
have “free space” to allow the buggy to stray from its path and past the finish line
If more than 1 track is used, contestants may choose which track to use. Both runs for a team will be on the same track.

12. The Competition During the competition the students:
will place their buggy's fixed pointer on the Starting Dot
will set the buggy in motion by actuating some sort of electrical switch. They may not touch it, but must use a dowel-like device.
The switch must be designed so the action to start it is either straight down or straight up.
A ‘sideways’ switch will be considered a construction penalty.

13. may use non-electronic measuring devices to verify the track dimensions (but they cannot use the vehicle to do so)
may place a target, which must be removed prior to starting each run, on the Finish Dot to aid in aligning the buggy
may ask that the bucket be moved before each run in order to align and aim their vehicle
MAY, between runs, remove/install/change any impounded parts, including batteries.

14. will be allowed 10 minutes to adjust their buggy and make up to 2 runs – if the a run is started before the 10 minutes is up, that run may be completed.
It is considered a run if the vehicle moves after the switch is actuated.
Must wait behind the Starting Dot during the runs until called by the Event Supervisor

15. Scoring - Measurements
For each run the judges will determine:
TIME SCORE: the time the buggy takes to travel the Target Distance. The time starts when the vehicle begins forward motion and ends when the buggy comes to a complete stop.
DISTANCE SCORE: the Distance from the fixed point to the Finish Dot. This is a point to point (straight line) distance, measured in mm.

16. Scoring - Measurements
If the vehicle goes in the wrong direction, it will be considered a failed run and count as a run.
If the vehicle inadvertently begins a run, it will also be considered a failed run and count as a run.
If the vehicle does not move upon actuation of the switch, the students may request another try and that attempt does not count as a run.

17. The Final Score will be the lower score of the 2 Run Scores.
Scoring - Points
The Run Score is equal to the sum of the following. Remember that LOW SCORE wins.
The Distance Score – This is the Measured Distance converted to mm, e.g. if the Distance was 10.4 cm, the Distance Score would be points.
The Time Score – This score component is the Measured Time x 25, e.g. if the time was 8.53 s, the Time Score would be points.
Run Score = Distance Score + Time Score
E.g. Run Score =
Run Score =
Ties will be broken by….
1st: Lower Time Score of the Final Scored Run
2nd: Lower Distance Score of the Scored Run
The Final Score will be the lower score of the 2 Run Scores.

18. Batty Buggy Systems Construction/Suggestions/Ideas
Possible ways to approach the event - May be consolidated or divided as necessary.

19. First issue – Kinetic Energy
Do whatever you can to increase the speed of the buggy!
Mass
Wheels – 3 vs. 4
Motor “strength”/torque/RPM
Efficiency of energy transfer
Reduce friction of the buggy components
Battery decision – what will give you the greater voltage and therefore the faster motor.
Anything else you can think of!!??

20. Body / Chassis Connects all of the other parts/systems together
Is probably the easiest to design and build
“A matchbox car CANNOT travel a desired path for a great distance.”
Therefore, make both the wheelbase AND the track as wide as the rules allow!
Be careful, “No 2 rulers are alike!”
Strongly consider some way to adjust the steering of your vehicle – “It is difficult to get the 2 axles to maintain their proper angles.”

21. Wheels and axles
Axles may be part of the transmission or a separate system
Wheels are VERY difficult to make exactly round  SO DON’T MAKE THEM!
Large diameter Wheel
Revolves fewer times to travel a given distance.
Transmission must have a higher gear ratio.
Vehicle might travel faster
Heavier
Small diameter wheel
Revolves more times to travel a given distance
Transmission can have lower gear ratio
Vehicle might travel slower
Lighter
Optimum size is somewhere in between
Affected by motor power
Affected by transmission gear ratio
Recommendation: Wide wheels tend not to drift as much and, IMO, tend to force the vehicle to go straighter!...but have greater mass.

22. Motor May be part of electrical system or transmission
Must be close to total battery voltage
Will operate within a wide voltage range - +/- 50% of rated voltage typical (but +/- 10% better for the motor)
RPM (speed) varies with load and battery voltage
Torque (power) varies with battery voltage
Few types available at reasonable cost

23. Transmission Most difficult to design / build
Reduces high RPM of motor to low speed for driving wheels
Several types possible
Direct Drive
Reduction Gear
Worm Gear
Planetary Gear
Belt / Pulley Drive (AVOID!)
Expensive to buy
Definitely a candidate for surplus / salvage

24. Electrical System Batteries Voltage should be suitable for motor
Larger batteries last longer / weigh more
Evaluate different types
Holder can be part of chassis or separate component
Motor
Terminals are almost always identified in some way. e.g. + , square, notch
If motor turns the wrong direction, reverse the wires connected to its terminals
Start Switch
Should be easy to operate
Should be in an accessible location
Can be “Home Made”

25. A great switch to use to start the buggy
A great switch to use to start the buggy. A micro switch to open the circuit at the end of the run.

26. Steering Mechanism
Adjusts buggy to travel in the desired path.
Adjustment need not be very large
Should retain setting reliably
Distance measuring device
Measures how far the buggy has traveled
Turns off motor
May apply brake

27. Stop Switch
Actuated by the distance measuring device
May be the same as the Start switch
Turns off motor to stop buggy
Could be used to apply brake
Wires
Almost any type of wire can be used
Don’t use too large a size
Stranded wire will flex more before breaking
Solid wire holds its shape better
For better reliability solder all connections

28. Brakes
All methods must involve either disconnecting the transmission or stopping/turning off the drive motor!

29. Brakes (cont.)
None – Coast to a stop – Called the “Prayer” method of braking!!
Easy to implement
Distance unreliable
Mechanical Types (tend to be easier to make)
String and Axle
Wheel Jam
Wing nut and Axle (by far the most popular)
Best combination: Have the wing nut not only lock the wheels but simultaneously turn off the motor with a mini lever disconnect switch.
Electrical Type
Use the drive motor as the brake – works best in direct drive transmission
A DC motor provides some dynamic braking when its terminals are shorted together.

30. Final suggestions
Think LIGHT LIGHT LIGHT
Design and build early!
Calibrate, calibrate, calibrate
Be as consistent as possible
Practice at many different track lengths
Keep a record of data
Try different batteries, motors
Did I say calibrate?
Will you use two different sets of batteries for the two runs?

31. Big questions !!!
How will your students design the front end to keep the vehicle going in a constant arc?
How will your students align the vehicle at the Starting Dot with the proper angle to get to the Finish Dot after going around the bucket?
Thinking time and time for you to contribute.

32. OK – get thinking!!!
Give an idea and get an idea in return.

33. Another disclaimer (mine)
The following pictures are simply to give you ideas. They are not drawn to scale nor is their any attempt to make them professional. I am not even sure that they even make the rank of amateurish.

34. Some ideas ?
The use of turnbuckles on the front axle will help to keep the turning radius constant.
Choice of the proper sized turnbuckles will allow a great range of adjustment to cover different course lengths.

35. Another general idea
Have several indicators on the vehicle chassis to reset to different angles for different length tracks.

36. One way to align the vehicle ?
Using a sighting device, the students can extend the direction to behind the Starting Dot.
After placing their fixed point on the Starting Dot, they can measure a pre-calculated distance from a spot market on the vehicle, thereby determining the proper angle.

37. Another way to align the vehicle
Offset the front sighting post
Have several pre-calculated sighting positions (for different lengths) offset at the rear of the vehicle.

38. Your students will come up with even more ingenious ideas for their vehicle.
Good luck to them all.