Using Omni Wheels to Produce Holonomic Movement

This is a summary of the project I created for the 2014 DC STEM fair. Here is the written abstract I submitted with the original project. In general, vehicles can move in two ways, along the forward-backward axis (x-axis) and by rotation, but they cannot usually move along the left-right axis (y-axis). However, it is possible to use omni wheels to create motion along both the x-axis and the y-axis, as well as at any angle. Omni wheels must be placed at angles to each other to control movement in multiple directions. The angles at which omni wheels are placed determines how quickly a vehicle can move in each direction. The purpose of this experiment was to find the speeds of different omni-wheel-based vehicles for each direction of movement. Four test vehicles, as well as a control vehicle that was set up with a non-holonomic drive configuration, moved away from an ultrasonic sensor at various angles. Speed was calculated by finding the slope of a linear regression of the position vs. time data, and speed at each angle was compared to a theoretical calculated value. It was found that none of the omni wheel configurations were as fast as a non-holonomic vehicle. Placing omni wheels at a 30° angle to the base allows for both top speeds nearly as fast as a non-holonomic vehicle and some slow holonomic movement. Placing them at 45° reduces top speeds further, but allows for equally fast movement along the x- and y-axes. If you have any questions about my project, please email me at [email protected].