Southern California Science Olympiad Summer Workshop Electric Vehicle C Kevin Kha

Rules Update (Paraphrased) 2.a.: The target distance will be posted after the impound time has expired. 5.c.: For the Distance Score, the distance will be measured to the nearest 0.1cm, not 0.5cm. 11/13/2018 California Science Olympiad Summer Institute

Overview Competitors construct a battery-powered vehicle to travel as quickly and as close to a Target Point as possible (9.00 to 12.00m) Much more power available than in other non-electric vehicle events (can accelerate faster) Microcontrollers allowed(can control acceleration and braking to prevent slipping, etc) Impound: Vehicle and spare parts Team of up to 2 Eye Protection: None Required 11/13/2018 California Science Olympiad Summer Institute

Construction Parameters (Structure) All parts of the vehicle’s wheels or treads must fit in a 35.0cm x 60.0cm space with no height restriction The only parts of the vehicle that are allowed to contact the floor during the run are the wheels/treads and those that are already in contact with the floor in the ready-to-run position. Piece(s) falling from the vehicle result in a construction violation The vehicle must be autonomous (not remotely controlled or tethered); The stopping mechanism must work automatically 11/13/2018 California Science Olympiad Summer Institute

Construction Parameters (Structure contd.) The vehicle must have a single ¼” round wooden dowel attached to its front end The dowel must be approximately perpendicular to the floor and be the leading edge of the vehicle at all times The dowel must extend at least 20.0cm from the floor 11/13/2018 California Science Olympiad Summer Institute

Construction Parameters (Power) Electrical energy in the vehicle must be stored in common, commercially available batteries, with voltage labeled by manufacturer No more than six 1.5V (or less) cells or a single 7.2V battery pack may be used at any given time during the 8 minute Competition Time Up to an additional six (for a total of twelve) cells or one (for a total of two) battery packs may be impounded. No lead-acid batteries are allowed 11/13/2018 California Science Olympiad Summer Institute

Construction Parameters (Power contd.) Electrical energy (stored in batteries) is the only energy allowed to propel the vehicle Capacitors allowed? Non-electric energy storage devices may only be used for functions other than propulsion, (e.g. brakes) All energy sources/storage devices must be easily accessed for inspection 11/13/2018 California Science Olympiad Summer Institute

Construction Parameters (Misc.) Components (e.g., motors, gearboxes, motor controls, bodies, and chassis) may be purchased or made by the competitors Remember that electrical energy storage devices must be commercially available and so cannot be made by the competitors Electronic components (i.e., solid-state devices such as transistors, integrated circuits, diodes, and microprocessors) are allowed The vehicle must have a vertically actuated button or switch to start the vehicle, pressed using an unsharpened #2 pencil Sighting, aligning, and guiding devices may not use electricity 11/13/2018 California Science Olympiad Summer Institute

California Science Olympiad Summer Institute Track Must be on a smooth, level, and hard surface Starting Line, Target Line, Timing Lines (0.5m and 8.5m), marked using 1.00m strips of ~2.5cm tape Starting Point and Target Point will be clearly marked at center of Starting and Target Lines 11/13/2018 California Science Olympiad Summer Institute

Track Diagram Lasers Stop Line 1.0m 0.5m line 8.5m line Start Line

Competition (Overview) 8 minutes to set up vehicles and complete up to 2 runs Time used by Event Supervisors for measuring must not be included in the 8 minutes Vehicles in the ready-to-run configuration before the end of the 8 minute time period will be allowed to complete a run. The team’s 8 minute time is paused when the vehicle stops to allow for the judges measurements. Timing resumes once the competitors pick up the vehicle or begin making their own measurements. 11/13/2018 California Science Olympiad Summer Institute

California Science Olympiad Summer Institute Competition (Setup) Teams can adjust their vehicles before each run only while in the start area and within their 8 minutes, as long as their vehicle still meets specs Changes to the vehicle may only use impounded parts Teams may measure and verify the track dimensions during the 8 minutes (but may not roll the vehicle on or adjacent to the track surface between the start and finish line at any time prior to or during the competition) 11/13/2018 California Science Olympiad Summer Institute

California Science Olympiad Summer Institute Competition (Run) Ready-to-run configuration: The vehicle must stay behind the Starting Line without being touched (and is ready to be actuated) To start a run, the vehicle must be in the Ready-to-run configuration. The Event Supervisor will then count aloud “1, 2, 3, go”. The team must actuate their vehicle on the word “Go.” Once the vehicle starts a run, the competitors must not follow it and must wait until called by the Event Supervisor. Run time starts when the dowel of the vehicle reaches the 0.50 m Line and ends when it passes the 8.50 m Line. 11/13/2018 California Science Olympiad Summer Institute

Competition (Run Scenarios) If the vehicle does not move upon actuation, it does not count as a run and the team may request to set up for another run, but must not be given additional time. If the vehicle passes the 0.50 m Line but stops before the 8.50 m Line, the timekeepers record the stop time, the distance measurement is taken, and the run is scored with a Competition Violation. A Failed Run occurs if the vehicle travels in the wrong direction, if a second run does not occur in the 8 minutes, if the time or distance cannot be measured for a vehicle (e.g., it starts before the Event Supervisor is ready, if it moves but does not go at least 0.50 m, or the competitors pick it up before it is measured). 11/13/2018 California Science Olympiad Summer Institute

Competition (Policies) Only competitors and Event Supervisors will be allowed in the Impound and Track areas during the event Once competitors enter the event area, they must not leave the area or receive outside assistance, materials, or communication Substances that may damage the floor or interfere with subsequent runs must not be applied to the wheels, treads, or floor. During their time, competitors may clean the track but it must remain dry at all times 11/13/2018 California Science Olympiad Summer Institute

California Science Olympiad Summer Institute Scoring (Overview) Low Score Wins Lowest Run Score is final score Run Score = Time Score + Distance Score + Penalties Time Score = Run Time x 5 Distance Score = cm from Measurement Point to Finish Point, to the nearest 0.1cm 11/13/2018 California Science Olympiad Summer Institute

California Science Olympiad Summer Institute Scoring (Penalties) Low Score wins, so penalties add points Penalties are run specific (apply only to the run they occur in, except for the Impound penalty) Each letter under Competition that is violated will incur 1000 pts penalty per occurrence for that run (maximum of 5000 pts) A run with any violations under Constr. Para. must incur an one time 7500 pts penalty for that run. A Failed Run’s run score is 9000 points. A Device not impounded during the impound period must incur 10000 pts penalty for each run. 11/13/2018 California Science Olympiad Summer Institute

Ties And Participation Points Ties broken in this order: 1. Lower non-used Run Score 2. Lower Time Score of the better run 3. Lower Distance Score of the better run Teams that don’t complete a run within 8 minutes or have two Failed Runs will be given participation points 11/13/2018 California Science Olympiad Summer Institute

California Science Olympiad Summer Institute Motors DC Brushed Motor: Simple, powerful, cheap, easy to use (just connect to a battery) DC Brushless Motor: Very powerful, fast Stepper motors: Very accurate and precise, slower, more advanced (need special drivers, etc.) 11/13/2018 California Science Olympiad Summer Institute

California Science Olympiad Summer Institute Motor Control The simplest way to get your vehicle going is to just have a switch, motor, and vehicle may slip a lot One speed only though, and faster is not better if you can’t stop where you need to However, if you use a microcontroller and a power transistor, you can use PWM (pulse width modulation) to control the motor speed, and can accelerate and brake more carefully to prevent slipping 11/13/2018 California Science Olympiad Summer Institute

California Science Olympiad Summer Institute Braking With electronics, dynamic braking is possible (use the motor to brake the vehicle); you may need an H-bridge for this if using brushed DC motor Be careful to not destroy your battery Can still use “old” methods of braking (string or threaded rod) BUT make sure you turn off motor when braking, otherwise you can wreck your vehicle (if the motor is on but something is stopping it from turning, it may destroy your vehicle, or burn out) 11/13/2018 California Science Olympiad Summer Institute

California Science Olympiad Summer Institute Components? Arduinos are a very popular (and cheap) microcontroller, easy to use, and very well documented Instead of using a mechanical trigger for braking (string/threaded rod), you can use an optical rotary encoder (with a microcontroller). 11/13/2018 California Science Olympiad Summer Institute

California Science Olympiad Summer Institute Tip Put a cushy bumper in front of your vehicle to help survive crashes Also include some kind of failsafe to turn off the motor if vehicle goes too far (can use string around axle to pull switch?) 11/13/2018 California Science Olympiad Summer Institute

California Science Olympiad Summer Institute Questions? 11/13/2018 California Science Olympiad Summer Institute