Omni-Drive 

An exploration in trackless wagon automation

The Design

The design utilizes two friction drives that act on a sphere.  This makes the sphere the friction drive of the device.  The premise in the mechanical aspects of the design were inspired by a simple ball mouse.  When looking at a ball mouse our hand moves the device which rolls a sphere across two wheels.  These wheels dictate an x and y axis which is graphically represented by a cursor on your screen.  The flexibility in movement from the cursor was a concept I wanted to explore.  In theory the x and y format would allow a device to move in a SL to SR, US to DS, and diagonally across stage.  The other interesting aspect is if two of these systems were used together you may also control a rotational motion.

The Prototype

In testing this theory I wanted the design to be able to be installed into a stock platform.  Also in the design I wanted to keep the height of the unit restricted to a manageable step height.  This Model sleeves between the 2"x4" in a stock platform and bolts to the platform.  The motors are mounted on a sliding plate so that they can be tensioned against the drive sphere.  The drive sphere is made of polyurethane (bowling ball).  The points that the drive sphere are pressing against are single ball bearing wheels.  These capture the drive sphere in place.  The unit is powered by DC control with two motor controllers controlled by Radio Control Signal.  The motor drive wheels are omni-directional so that friction isnt an issue when the ball rolls the opposing way of the sphere drive wheels.