Control Loop Cup Holder

Made by Rory Hubbard

Created: February 14th, 2019


Within the last year I’ve grown to like coffee more and more. At first I would drink it just for the caffeine buzz but now I drink it more casually, whether it be with a friend or by myself. I enjoy it in all forms. For this project I decided I wanted to make a cup holder that could hold multiple espresso shots. And since coffee has helped me get through many of my engineering projects I wanted to include some sort of engineering aspect to my cup holder design. I’m very interested in control theory and one of the coolest aspects of this kind of engineering is the control loop diagrams. I thought that a control loop diagram with the summation junctions acting as the espresso shot holders would be a cool cup holder that I would actually end up using. So I first went back through my classical control notes to decide on a loop diagram that I liked. I decided on the general two degree of freedom control loop diagram shown below.


This diagram is directly from my class notes. As noted on the diagram itself, it ignores the noise input and sensor transfer function. For my cup holder design, I wanted to include these components as they are very important for designing a robust controller and more importantly, it would make my overall design look cooler. Next I went straight into SolidWorks to start designing.


The main challenge with designing this diagram was deciding how to constrain it. A control loop diagram can look any way you want it to so the possibilities were endless. I first decided that I would constrain my design by limiting myself to one 12” x 12” sheet of acrylic. The reference lines around the CAD shown above represent the sheet of acrylic that this piece will be cut out of. While the CAD above shows a lot of dimensions called out, I actually designed most of it just by using reference lines and sketch relations. This made it a lot easier to mess around with the key dimensions. After I had the control loop diagram looking the way I wanted it too, I needed to make it one continuous piece. This meant that I had to delete the reference lines and replace them with dimension callouts. The CAD below shows the final part.


The rectangles pointing inward in this CAD are not a part of the control loop. Those will be heat formed and bent downward to act as legs for a table while the actual control loop acts as the table top.


I maximized my use of space within my 12” by 12” piece of acrylic by ensuring that the largest dimension of the entire control loop diagram (reference input to system output) was cut along the diagonal of the acrylic sheet.


The only thing left to do after the part was cut was to heat form the four legs so that the control loop diagram was lifted off the ground.

    This was a relatively easy heat forming process.    

The finished cup holder is shown above.

The mood board shown below gives a glimpse into a typical day in my life.

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