Robotics Education & Competition Foundation
Inspiring students, one robot at a time.

Expansion Wheels


Entry ID #: 6441
Created: Tue, Jan 15, 2019 9:12 AM

These wheels were created to solve some of the problems presented in the 2018-2019 VEX Robotic Competition, Turning Point. Some of the game components of includes  2.4 in. and 4.9 in. parking platforms, flags about 18.25 in. apart from each other, and the 18 by 18 restraints. When extended outwards. these new wheels would provide a height advantage and be harder to move. This makes it easier to go over the parking platforms and stay on the platform without other robots pushing your robot off. Extending or constricting the wheel would also improve how we angle the the shooter, and could let our robot expand the 18 by 18 limit after the start of the game. When the wheel is constricted, it allows for more smooth motions when driving making driver control easier, and lower the robots center of mass making it harder for the robot to topple over. The wheel will extend or constrict when the outermost part of  the wheel (Outer Ring) cannot move (either by driving the wheel against a wall or adding a motor mechanism that physically stops the wheel). When the Outer Ring cannot move, the Inner Ring will of the wheel will start spinning. The rotation of the inner section of the wheel will allow for the extension and constriction of the wheel. The piston (the part of the wheel that actually extends the wheel) lays on a special type of sprocket that is present on the inner circle. The teeth of the sprocket have an indent for where the piston rests when it is extended. When constricting the wheel, the piston will lay on the trough of the sprocket (here the piston is closest to the wheel and so the wheel is constricted). When the Outer Ring is not locked, the Inner Ring will no longer rotate causing no extension or constriction, and allow for regular movement.   Using Autodesk Inventor Professional 2018, we started by creating the base of the wheel by sketching out the basic elements of the wheel. We decided to make the wheel about the same width of a regular wheel, with about the diameter of 3.2 in , not including the extenders. To the first insert point, we created a circular pattern so that we could have multiple intake pins, and created the holes with a work plane for the extenders. Then we created the extension part of the wheel. We started the extension by creating the cylinder that is inserted in the base of the wheel. On the cylinder we took used the same width from the base and created the curved grip that would increase the area that is exposed to the surface. When put together, we restraint each component so that the extenders move only how they would in real life. This project taught us to think outside the box, and include real components that are practical. It introduced us to the different ways to brainstorm and model with CAD Inventor that we can implement in our design process. It would not only be more precise, but it will help us visualise how different components of our robot can work together, and what components should be removed. This would also help us with recording how our robot has evolved over time. Learning 3D design will not only help us in this competition, but it will also help in our future career path as an engineers. Thinking in 3 dimensions will help create future inventions and will give us a head start in the professional world.

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