Build Progress: February March April May
March
Picking a speed controller
We considered using a Vantec speed controller, but worried that the peak amperage was too high for the RDFR23, which was the only real option for our price range. Instead, we decided to go with a pair of Innovation Victor 833s running at 24 volts, since they could handle higher peak amps. We picked up a Omark radio mixer at the recommendation of TeamDelta to allow single stick control of both speed controllers.

Gear Box Built
In order to use the windshield wiper motors effectively, we had to design and build a gear reduction assembly. The 16 pitch aluminum gears used were purchased from Berg. They were chosen so that we would get approximately a 6:1 reduction. The box to hold the gears was machined out of aluminum. This allows the lifting arm to move through a 90 degree arc in approximately 1.5 seconds.

Frame building begins
We picked up the steel tubing locally at a steel fabrication shop. After cutting the tubing to size, two wheel housings were welded together. We did not initially weld the two wheel housings together, so that we could double check our CAD model and ensure that everything would indeed fit. Once we were convinced everything would fit, we installed the cross braces.

The wheels came with internal roller bearings, so we opted to use these bearings so that we didn't have to build a hub and pillow block assembly. Instead, we attached brackets to the frame, and ran the original 1/2" bolt through the brackets.

Drive Train Assembly
Simple motor mounts were designed and then fabricated from 6061-T6 aluminum. Sprockets were attached to the wheels with four socket head cap screws tapped directly into the wheels plastic core. This was done due to not needing a hub assembly, as described above.

To attach a sprocket to each motor, we used .060 wall 1/2" diameter steel tubing and drilled and tapped the tube for a 3/8"-24 bolt. This was the thread on the output shaft of the drill motor to attach the drill chuck. The original reverse thread locking screw was re-used. The 1/2" bore sprocket could now be mounted to this adapter.


Build Progress: February March April May