King of the Hill (In Progress)

About the Project

The objective of this project is to create a robot (max 15cm x 15cm, length x width) which can climb up a laser-cut hill and stay on the top as long as possible to earn points. The longer you stay on the top of the hill, the more points you get, and the person with the most points at the end, wins. (Points are detected using rfid tags which are attached to each robot).

Preliminary Drawings

The idea of this first preliminary drawing is to attach a propeller on the top of my robot to try and get other robots to move out of the way and get my robot to the top as soon as possible.

My second idea was to use suction cups and attach them to the bottom of my robot to keep it in place at the top of the hill. I ended up going with a similar design idea to this, except since suction cups are hard to stick onto the surface of the plywood of the hill, I am researching more about an easy to use material to attach at the bottom of my robot in order to prevent others from pushing my robot off the hill.

This third idea uses inspiration from military tanks in its wheels to try and make the robot as sturdy as possible, making it very hard to push.

Very Preliminary Onshape Modeling

The Outer Shell

Uses a basic four wheel drive gear system that uses one motor on each side to turn the two wheels on that side. The front has a inclined slope attached to it to make pushing other robots easier. I want to make this slope automated in the future by adding a hinge.

The Friction Pad

In this model, I am using a cam mechanism powered by a microservo to push the friction material (black part in the image) onto the ground. The screw will also have a spring attached to it to help bring the friction material back up. I will also need more support for this mechanism.

The Two Stage Gear System

I updated my gear system to a two stage one and made my wheels thicker so that my robot can be even harder to push.

First Physical Prototype

The first prototype had a few issues: The screw holes were too tight so as the wheels spun, the screws were tightening and breaking the wheels. Also, the slope at the front left no gap between the ground and the robot, making it extremely difficult to climb up the hill. The side gears also had no protection, making it easy for other robots to hit them from the sides. Finally, the cam mechanism involved a spring and I realized it wasn't too sustainable after testing.

Fixing the Above Described Issues

Final Design Images

The bottom piece is the part that attaches to the cam mechanism. It is a thin 3D printed piece with the tire material wrapped around it. The thickness caused issues in the final result on the hill, though.

Arduino Code

Final Result Video

roboticsvideoKOTH (1).mov

Improvements and Successes

The bottom pad was too thick (I would want to make it thinner by not wrapping it with tire material and picking a material that would work on its own to mitigate thickness and allowing my robot to move much more freely when the pad is not in use) and it didn't allow the mechanism to be used successfully due to its thickness.
The design, aesthetics, and two stage gear system were all successful.
More gear ratio testing to help climb the hill more effectively would help. In the video my robot struggles to climb the hill fully, although when testing on my own (without the rest of the robots) it is able to successfully climb the hill. More gear ratio testing to find the optimal ratio would've helped solve this problem even with crowding.

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