PROFILE


    NAME: HR-702S
    YEAR: 2008
    TAGLINE:"Slow Traffic Move Right"

  • Ranking and Awards:

    Los Angeles Regional:

    15 out of 51
    Regional Finalists (Second Place Finish) Eliminated in the Finals in 2 matches
    Record:(9-7-0)
  • Drivetrain:

    Direct Drive
    Center Wheel "702 drive"
    Andymark Kit C-Channel Frame
    2 16 inch pneumatic tire drive wheels (no that isn't a misprint, 16 inches)
    4 6 inch Andymark support wheels
    2 CIM motors per drive wheel
  • Mechanism:

    direct drive
    PVC overtop ball herding claw
    Window Motor driven
  • Software and Control

    Language: EasyC Pro
    Driver interface: XBOX 360 Controller/ flight stick claw control
    Gyro sensor to maintain course
    Infrared sensor to detect signals from human player dvd remote (no misprint there either, it was a dvd remote) Tank Drive Controls
    Note:Last year of the IFI robot Controller electronic interface
  • Autonomous function:

    Drive straight forward until it receives command from the dvd remote, then make a left u turn
    Reliability: 75% until gyro failed, then autonomous disabled

Game

  • Field:

    The field was split in half by a clear plastic barrier making an oval track. Each alliance's finish line was in the middle of the field, one on each side of the barrier. The finish line has a 6 foot tall arch over it where the balls start the match at.

    Primary Scoring:

    A salute to NASCAR, each alliance gets 2 points for every lap they make. If a robot pushes one of their alliance 36 inch diameter balls through the finish line first, it receives 2 points as well. If a robot puts the ball over their finish line arch, it receives 8 points.

    Bonus Endgame:

    Placing a ball back on its arch will receive 12 points

    Autonomous scoring:

    Autonomous crossing of each track line (4 total) receives 4 points. Autonomous removal of the ball from the arch receives 8 points.

    Penalties:

    (Each penalty deducts 10 points from the alliance) Moving clockwise around the track (penalty for each instance of breaking the plane of a trackline in the wrong direction.) Posession of more than 1 trackball or posessing an opponents trackball. pinning or refusal to allow a robot to pass for more than 6 seconds. Interfering with a robot putting a ball over the arch.
  • Download the Game Animation here.

Coach's Notes

    After 2007, people said we were overcompensating. Everything about this robot was built for speed including its name. HR-702S sounds like a german sports car name. (HR stand for Hit and Run because it was too small to ever push another robot. So our driver was instructed to never get in a pushing match. just hit the other robot and take off before they notice.) This robot was much smaller than the regulation limits and much lighter. (no need to worry about weight limits here) Its 16 inch wheels were designed to gear down the transmission giving the robot less torque but a higher top speed. The claw mechanism was made of PVC pipe to keep the weight down despite its obvious tendancy to break. When we designed it, we knew this and made sure each piece was easy to replace with additional premade parts. We also designed it knowing the ball would be quite literally bigger than our robot. Rather than try to pick up something that big, we essentially caged it from the top. That way we just controlled where the ball rolled and never took it off the ground.

    This was the last year of the IFI robot control and electronic system. It was starting to show its age and limiting what robots could do both autonomously and in teleop. However this was the first year where game controllers could be used to drive. It required a strange adapter and only worked with certain controllers. Fortunately xbox 360 was on the list and we have not gone back to flight sticks for driving since. This was also the first year of mandatory bumpers. Although many in the first community grappled with the lack of standardization of the "pool noodle" (I don't think ASME is going to be covering that standard very soon.) The bumpers had an unintended effect on our ball handling. When the claw fit over the ball, it pulled the ball into and over the front bumper slightly lifting the ball off the ground. It gave less friction on the ground and made the ball more like a part of the robot. The result, very little loss on speed or maneuverability while doubling our point production. For once, the law of unintended consequences went in our favor.

    We designed this robot in the simplest way possible. It was built for speed and maneuverablility and had an interface that was very familiar to the driver. (We gave a teenage guy an xbox controller, probably the most familiar control system to any video gamer, and told him to use it to drive the robot.) Our robot under that kind of control could dodge, drive, and even power slide around the turns at full speed rarely, if ever, slowing down. It proved that simplicity is always best, and that simple design carried us all the way to the finals.

    In the end, it took 2 things to finally defeat us. It wasn't the pvc claw which did not break until the final matches. (We had to splint it because there wasn't enough time to replace the piece) It also wasn't because of what many people said, that we were on the weakest alliance out of the 8. Our alliance looked weak because the 3 robots were all based on a simple design, one that could only drive laps, one that mostly could only lift the ball over the arch, and us that could carry a ball fast but not lift. Despite that, we worked as a team, one lapping, us carrying balls around, and the lifter parked at the arch waiting for us to deliver the ball and put it over. That teamwork got us through to the finals. In the end it took 2 parts of our robot to finish us. The gyro sensor failed making autonomous dangerous forcing us to disable it. The second was the window motors. Based on a worm gear design, they handled our claw deployment, but the gears were made of plastic. One solid hit in the finals and both motors stripped. The claw was disabled, breaking the assembly line style scoring. It wasn't enough to compete with the winnning alliance. It is still our highest achieving robot and will always have a place of honor in team history.