Gap Crossing Robot Documentation
When we were first given the task of creating a table-gap crossing robot, we first brainstormed as a team several possible solutions to this challenge. After thinking about several robot designs we decided that the best design would be to create a long robot with four wheels connected in a long straight structure. As we went along with building the robot we constantly tested our design and made improvements. We noticed that the longest gap length that our robot could cross was limited by the distance in between the first and second wheel of the robot. Therefore, we tried to maximize this distance while retaining structural integrity of the robot.
For the mechanics of the robot, we decided to make the structure of the robot as long as possible so that it would be stable when crossing the bridge. We started by assembling what became one of four “motor/wheel” assemblies where a large rubber wheel was attached to a frame that was on the case of a motor, and smaller rubber wheels were attached to the motor which spun the large rubber wheel. This was by far the simplest and most efficient way to drive the wheels for this application. To make the robot as long as possible we used 4 of these assemblies, two pointing one direction, and two pointing the other direction away from the brick. The brick sat in the middle with a simple code to run the motors in the right directions based on their orientation. We attached the motors together and to the brick with a simple and lightweight structure of beams, and added some skids on the side of the brick to help it lift onto the table when exiting the gap.
For programming this robot we used LabVIEW. We implemented a very simple code that immediately turned on all four motors at full power. We had the two front motors spin clockwise and the two back motors spin counterclockwise so that all four wheels were being driven in the same way. We just had this run for 80 seconds in the code, but just stopped the code manually when the robot cleared the gap.
10 inch gap successful crossing
16 inch gap unsuccessful attempt
Video description of robot mechanics