The original drafts for the cat toy explored ideas on how we wanted to approach the mechanism’s function. We wanted the toy to have random movements to keep the cat entertained.
Our first ideas were too focused on generating random movements through the use of programming. After meeting with the TA and reviewing some new ideas, we decided to power a four-bar rocking mechanism with a motor, and have it roll over a cam system to create unique vertical movements.
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This plan allows for 2 degrees of freedom using the constant rotation of the motor as the only input. While the mechanism will inevitably begin to repeat itself given enough time, the amount of freedom using a cam system gives in designing a pattern for the toy suppresses this issue into insignificance.
The process for creating the prototype was very simple. We repurposed the links for the slider-crank mechanism created earlier in the semester by changing their lengths. We then laser cut the links and fashioned them into the crank-rocker. Then, the vertical path cam and temporary cat wand were cut out. The cam was attached to a base with the crank-rocker and the cat wand was attached with a hinge to the output link.
It may also be possible to allow for 3 degrees of freedom by implementing a four-bar slider mechanism that will push the toy in and out. While this will not be a part of the prototype, it could be possible to add it afterwards.
