Team members: Teguh Hofstee
This project aims to make a latte art machine that can create free pour latte art. This is different from existing latte art machines as those typically print an image using something like cocoa powder, drops of coffee, or edible ink on a layer of foam. The resulting art created has a very different aesthetic to traditional free pour latte art, and personally I think loses some of the charm of latte art. One machine that tries to do this does exist[fn:thermoplan], but is built into an espresso machine making it very expensive, and doesn’t generate particulary good results. This system would be free standing.
Originally the plan was to build two separate machines, one as a dedicated cup holder and one as a milk pourer, and tailor them to the specific kinds of motions needed for each half. Essentially some sort of pan and tilt stage for the cup, and something more complex for the pitcher. Pat said it would look cooler if the two halves were essentially robotic arms, akin to some of the robotic bartenders.
While I don’t disagree, I’m not made of money so I’d like to keep it relatively budget conscious. The pitcher itself is probably going to hold 6-8oz of milk, which puts it at about 385g. While this isn’t extremely heavy, it’s still heavy enough to concern me about having sufficient torque in an articulated arm using relatively inexpensive parts. Additionally an articulated arm would probably need to be about 5-dof, which adds more complexity than I think is really necessary. It does have the benefit of being able to make one, and essentially duplicate it for the other half though.
Instead what I’m planning to do is to make the pitcher half of the machine. I’m planning on making a SCARA arm with 4-dof (no z). This should also help to deal with the torque issues since the force can be exerted more on the structure and have reduced effect on the torque that needs to be produced by the motors themselves. For the cup half, at least for now I’m just planning on using my own hand, which I guess also sort of makes this a bit of an interactive machine.
I think the hardest part of the project is going to be the control. Beyond just getting it to create a single design, creating new designs will also be tricky. Adding some degree of interaction to “train” the arm to create a new design might be helpful, but I’m not entirely sure how to design a system that reacts correctly to external force besides just duplicating the structure with encoders instead of motors. Creating some sort of simulation that could approximate images with free pours also could be neat, but is probably way out of my depth. Simulating the result of an existing free pour has been done before[fn:simulation], but reverse engineering a pour from art as far as I can tell has not been done.
- [x] CAD design of arm
- [x] Order parts
- [x] Practice making latte art while waiting for parts
- [x] Assemble arm
- [x] Basic movement with arm
- [ ] Figure out parameters for smooth pouring
- [ ] Evenly pour milk into cup for consistent color
- [ ] Try to get basic latte art shapes created
- [ ] Explore more complex art as well as ways to control the machine
- [ ] Inverse fluid simulation
Will be updated over time, tentatively either relatively high torque servo motors or a few NEMA17 steppers, and something to program and control the motors. Other parts are not set in stone yet but I have a reasonably comprehensive idea that will probably result in buying some modular parts from ServoShop. Rotational or magnetic encoders might also be useful to get positional feedback (even in the case of using servos as you can’t query a servo for its position).
- Calipers
- Towels
- Cup
- Pitcher
- Emergency stop button
- ???
[fn:thermoplan] https://www.thermoplan.ch/en/latteartist [fn:simulation] https://dl.acm.org/citation.cfm?id=2542344