4.) Prototype

Build Iteration 1: Initial linkage mechanism testing

Description: The links of the mechanism were ¼” thick wood, chosen for its low cost and ease of shaping, and were laser cut for accuracy. To ensure that it matched the expected movement and was relatively smooth, we assembled the links using M4 screws and nuts and tested the mechanism.

Results: Through testing, we were able to confirm that the links were dimensioned and prototyped appropriately, as the linkage mechanism was moving as expected. However, on the first iteration of this prototype, we noted that some links were redundant and could be combined with other links. Thus, for the second iteration (discussed in more detail below), we streamlined the design.

Build Iteration 2: Linkage mechanism with actuator

Description: On the second iteration, while most parts were again cut from 1/4" wood, we added some that were made from 1/4" acrylic via laser cutter. This was to make "hidden" linkages, or, in other words, make linkages that were going to be exposed in the final design less noticeable. This design, unlike the first iteration, had a bigger back plate that allowed a motor as well as electronics to be attached for proper actuation of the input link of the linkage mechanism. This is also the first design in which we have implemented a uniquely shaped link that resembles the leg of a dog, of which more iterations would done in the future.

Results: This build iteration matches our desired linkage movement, however after obtaining feedback we had to modify the linkage system quite a lot to change the motion to more resemble how a dog walks. Additionally, we found that shafts and collars would be more effective for the joints than screws and nuts, as this will solve some issues that made themselves apparent in this prototype, such as the unscrewing of the nuts and high friction in the joint itself.