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Cheese Wedge

Class: Mechatronics (ME 353)

Year: Spring 2019

Goal: Design, fabricate, and program a fully autonomous sumo robot that can stay inside the ring and push competitors out of the ring, with given rules and specifications.


  • black body to stay "visible" to other robots, to dig under and scoop the other robot to push them out of the ring

  • white back to stay "invisible" to other robots, so that they cannot push the robot out of the ring

  • IR Sensors to detect the ring

  • stayed under the weight and cost limit by more than 50%

  • "kill switch" to turn the robot on and off easily

  • removable battery pack


Technical Details

The robot needed to stay inside the "ring" of 3 ft x 3 ft square made from neoprene rubber, with the robot considered to be "out" when more than half the robot is no longer within the main area of the ring. To do so, Infrared Sensors were mounted on the robot to detect the ring by the amount of reflections.

The robot was designed in the shape of a right triangular prism, with color manipulation. The ramp makes it easier for the robot to able to push its opponents out of the ring, by digging under them. The black body also encourages the opponents to come straight to the ramp, to be pushed out of the ring. The white back makes the robot "visible" to others, confusing the opponents to think that the robot is part of the tape, so that the opponents cannot push the robot. To ensure that the robot does not fall apart, sawtooth edges were bound together. The sides were also reinforced with 3D-printed L-brackets for serviceability, to ensure that they are removable to be debugged or fixed if needed.

The electronics feedback loop for the robot is composed of the IR Sensor, the PIC 18F4520 (the computer chip), the H-Bridge, and the motor. The IR sensor readings are sent to the PIC, and the PIC program determines what to tell the H-Bridge to move the motors in different directions. The algorithm for the PIC is so that if the IR sensor reads the ground as the tape ("white"), it stops, rotates, and moves the other direction. If the IR sensor reads the ground as the mat ("black"), it continues to move in the direction that it was moving.

The robot only costs around $100, and is light and portable. All parts of the robot are RoHS compliant. The robot was able to push other robots, and to stay within the ring. Stronger motors (with higher torque) or adding more weight to the robot could enhance its functionality.

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