Fabrication and Assembly - Team 1

Nearly every part of this robot was designed to be laser-cut from 3 mm thick acrylic, thus we spent nearly a total of 15-20 hours on the laser cutter. Before we could begin cutting all the parts, we wanted to ensure that our tolerances would be met so we made some test cuts for our 6 mm bolt holes (used for the joints) and our ¼” d-shaft holes (for our driving link). Each hole size varied by a thousandth of an inch, and the laser cutter has the resolution and the repeatability to reliably keep our tolerances for all the holes within a thousandth of an inch.

Now we determined the sizes for the important dimensions, we were able to update the CAD models to meet the new dimensions and begin cutting our actual parts.

Here are most of the parts to the robot cut and ready for assembly.

We also had to machine a lot of spacers at varying lengths out of Delrin rod.

With the spacers and acrylic parts complete, we began our assembly with the legs. The legs are composed of the acrylic links, PTFE washers, 6 mm bolts, locknuts, and the Delrin spacers. We tightened the bolts and nuts down until there was minimal axial play but allowed the links to rotate freely.

Next, we built the main frame robot. We used JB Weld adhesive to bond the frame walls to the base and to secure the corner gussets in place. Keeping the bolt cross bar supports and the shafts in, we could ensure correct alignment.

Next, we installed the shafts, pulleys, collars, and belts followed by the six-bars, and lastly the legs.

Everything fit as it needed to, however, we noticed a major issue with the design of the six-bars and how it would be actuated by the ball joint rocker system. Because the ball joints only pulled from one half of the six-bar it could not effectively alter the position of the joints on the far end. Thus, we needed to extend the servo’s reach with a shaft and a second ball joint rocker. A few parts were altered and laser-cut and an aluminum shaft was machined.

With all the mechanical design elements assembled, we could now install the electronics and wiring. Casings for the electronics were 3D printed to fit perfectly with our frame and zip tie anchors were used to secure all of the wires. For the cherry on top, we printed a longhorn head from resin to be our robot’s figurehead.

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