Button Pushing Machine

In my machine design class as a group of 5 we designed a powered button pushing mechanism. Our goal was to design a mechanism that pushes as many of the button pairs as possible in 1 minute. In addition we were incentivized to minimize the volume of the mechanism and transmission angle. The project was graded in terms of our performance relative to the other groups.

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We designed our 4-bar linkage using a graphical method to ensure the mechanism would be able to reach all the button pairs with a single motor. A transmission angle of 90 degrees is most energy efficient, however we also sought to minimize the overall length of the linkage to minimize the moment of inertia. We decided to use a solenoid instead of a servo to trigger the button given the additional speed, minimal additional weight, and simple control mechanism. Next we designed our transmission mechanism using inertia matching to calculate the ideal mechanical advantage between the motor and linkage while factoring into account the resolution of the motor encoder. Finally we machined all the components from aluminum, assembled the mechanism, and set up a PID controller for each button position. 

Our group performed exceedingly well. We placed in the top third of the class in all metrics. We were able to trigger 138 buttons in one minute, a volume of 360 cubic inches, and an average transmission deviation of 11.7°.