The team began the design process by making SOLIDWORKS models of the linkages. From the previous page, we can see that there are two triangles formed by links BDE and GHI. We decided to turn these separate binary links into ternary links in order to simplify the assembly of the mechanism. As you can see in the picture below, each set of legs has four binary links and two ternary links. The circular plate with a pin shown in the middle of the image attaches to the 360 motor through another piece called the joint mount. All parts shown on this page were 3D printed with PLA.
Figure 3: Cura Model of Linkages
Figure 4: SOLIDWORKS Model of Joint and Motor Mount
The joint and motor mount shown above was designed to hold the motor and ground two of the ternary links with a few binary links. The grounding of these linkages allows the walking motion to be achieved. The circular plate with the pin was hot glued to the motor fin. The part of the motor fin that connects to the motor fits in the middle hole of the mount because we filed the hole down to be big enough to allow the motor fin to rotate freely. The left side of this mount was raised 8 millimeters in order to compensate for the height discrepancies caused by stacking the links on the circular plate's pin.
Figure 5: SOLIDWORKS Models of Pin Joint and Cap
Figure 5 shows the pin joints and caps that were designed to connect the ball bearings to the links. Several versions of these pins were created because we needed pins at different lengths. The outside radius of the pins had to be filed down to press fit in the bearings. The layering of the PLA allowed the caps to fit and lock within the slot made in the pin joint. The pins fit perfectly inside the holes at the end of the binary links so no adjustment was needed there.