About our Robot; “Tigerlily”

THello meet “Tigerlily” our robot for this years game, Cascade Effect. Here is what she does:

TIGERLILY

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Autonomous 

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At the start of every autonomous program we have created/entered various void commands to make coding the programs easier. We developed these voids based off of our past experience with NXT-G my blocks; these voids allow us to pre-set parameters for time or distance, easily reset encoders, set servos, and simplify commands which we use repeatedly.

 Ramp Start #1(pink):  Uses encoders and ultrasonic sensor

  1. Place robot against the wall on the rear of the ramp and wait for start. Using motor encoders to document the rotations, where the value was adjusted to allow each number to represent one wheel rotation, the robot drives a set distance off of the ramp forward.
  2. The robot then spins and backs up into the wall to straighten itself out.
  3. Then the robot drives forward towards the center (using encoders) and turns to face the medium tube.
  4. Robot backs up while reading the ultrasonic sensor until the tube is 30 cm away or until one second has passed, this prevents us from sometimes missing the sonar reading if it is not perfectly aligned. It then backs up half a second while dropping the grabbers to attach to the tube base. The small ball is then dumped into the tube.
  5. Robot drives to the front of the ramp, using motor encoders to measure rotations, and then turns to the right to aim towards low parking zone.
  6. Using the motor encoders, the robot drives a set number of rotations to get to the top of the parking zone, before spinning and backing the tube into the parking zone.

Floor Start #1 (green): Uses encoders and infrared sensor

1. Robot starts against the wall and drives forward using encoders.

2. Using a variable IR sensor program, the sensor checks to see if the beacon is 90° left, 45° left, or straight in front.

3. If the IR sensor reads 0, the robot turns left and backs into the pole to knock it over.  If the IR sensor reads 3, the robot backs up, turns right, and drives forward into the pole to knock it over.  If the IR sensor reads 5, the robot turns right to go around the center console to knock and knock the pole down.

 Floor Start #2 (blue): Uses encoders

  1. Drives forward a set distance using encoders.
  2. Parks in front of opposition tubes at the end of opposition ramp while still allowing access.

 Ramp Start #2 (yellow): Uses encoders

  1. Robot drives down the ramp a set number of wheel rotations using encoders and stops.
  2. Robot remains in this position allowing the alliance partner to get by and access the tubes if they can score the preloaded balls.

Tele-Op

Tigerlily’s main objective for Tele-op is to pick up 4 large whiffle balls in the custom plexi-glass hopper and dump them in the center goal during end game.  This makes her a desirable alliance partner. The scooper can collect 4 big balls at once (it filters out the small whiffle balls) using a 360-servo, holds them in the hopper until endgame, raises her 4-tandem rack-and-pinion slides, reverses the 360-servo, and then dumps the large balls into the center goal. Tiger Lily can also to drag around/deliver a graduated cylinder (with two grabbers attached to the back of the bot) and put them easily on the ramp. She can also end the game on the ramp.

Tigerlily is a large heavy robot who can also play defense due to her size and quick maneuvering ability; she has 4 independently powered wheels, with the front two being Omni wheels for a quick and small turning radius.

Decorative/Aesthetics:

LED lights (RGB strip) indicate which alliance we represent, and are wired in parallel with the servo and motor controllers which are all connected using ferrules and power-poles to the tetrix battery. These are not programmed or controlled by the NXT or autonomous/teleop programs; they are toggled on and off by connecting or removing power. They are not used as an indicator of any kind and are not connected to any sensors.

There are also a number of 3D printed stars for decoration. Pink, of course!

Additionally, the wheel barrier and “mud flaps” are custom cut and decorated with hand-drawn designs cut with vinyl stickers. They are functional AND cute!

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