How we built our Robotic Bubble Tea Station
This post is written by our in-house R&D engineer Thomas Hodges.
Robotic Bubble Tea Station — The Brief
The idea of producing an automated drinks station is nothing new, but specifically an automated Bubble Tea station has its own problems and remained largely unsolved. The key issue is that you are dealing with a mix of liquids and solids, and these solids also stick to each other when stored outside their normal liquids.
Given Taipec's strong culture of innovation and its past collaborations with the University of Cambridge, University of Bath, and the Royal Academy of Engineering, and its commitment to developing staff, I could not help but be attracted to this challenge.
The Timeline
Our target was the International Food and Drinks Exhibition which ran between 25-27th March 2024 at Excel London.
Having joined Taipec in August 2023, I had to ask first: is this achievable? What do I have to learn? What's the timeline like? When setting out I knew I had to meticulously plan for and schedule down to the day, the goals I needed to hit and the skills I needed to gain.
For such a complex system like this, what I learned from doing this is that my timeline worked the most effectively when not meticulously planning every minute detail, but instead only capturing key project milestones and deadlines I needed to hit first, then planning for each deadline individually as they come. Although this may not work for everyone, I found that this way allowed me to remain flexible to tackle each challenge with a fresh mindset and more knowledge than if I planned from the start.
The challenges along the way
The project came with its challenges.
1) Collaborative Programming with the Robotic Arm
I tackled the most challenging programming problems collaboratively my software engineer colleague Eamonn Rolander. While he was working here over the summer, he wrote the core code base for working with the robotic arm and conceptualised the communication network that I would go on to completely flesh out and implement. This laid the groundwork for a lot of the more complicated communication with the two RaspberryPi wired into motors and our cup sealing machine as well. Having these tasks out the way early led me to be able to focus on more laborious and time-consuming parts of the project later on.
2) Managing High 3D Modelling Workload
An aspect which was high workload was the amount of 3D modelling and 3D printing required. My strengths lie in 3D modelling, which proved invaluable in such a time-constrained environment. Although I considered using designs which involved complex organic forms, I opted for rectilinear bodies and shapes due to the time constraints and being more in line with Taipec logo’s design style.
3) Testing Material Strength with Finite Element Modelling
I ran Finite Element Modelling on various plastic materials such as PLA (polylactic acid) and PC (polycarbonate) to determine the forces on the material. This would dictate how thick and how strong to print these parts. There is the additional complexity that they do not behave isotropically, meaning that their strength and stiffness depend on the direction of loading and resistance to that load.
4) Overcoming 3D Printing Bottlenecks
Leading up to the exhibition, we encountered significant setbacks, with the primary one being a 3D printer bottleneck. Given many components would take 3-4 days to print, and often failing a couple of days into the process, we invested in two additional printers, as the time saved fixing faulty prints greatly outweighed the cost of the extra machinery.
The most troublesome part of 3D printing was the popping boba dispenser. Its parts repeatedly failed to print despite numerous attempts, wasting significant amounts of PLA filament and time. As the exhibition date approached, we considered outsourcing to a 3D printing service as a backup. Thankfully, this wasn’t necessary. Through trial and error and careful research, I eventually found the perfect settings for the material. This process tested my resilience, as I had to try multiple solutions until I succeeded.
Another unexpected challenge appeared during the “wet-runs.” The extra weight of all the liquids caused problems for the plastic attachments on the robot grippers. Fixing this was straightforward by adding a rubber sheet improved the grip. However, I now realise that “wet-runs” should have been conducted from the start, rather than waiting until we were close to the finish line.
Dress Rehearsals
Additionally, facing the task of setting up and recalibrating the robot within a two-day timeframe was a daunting challenge. With limited time and resources, I focused on carefully measuring and ensuring consistency in the setup. I then programmed the robot from the start to guarantee accuracy in its movements. Precision is critical, as the robot must operate within 1 to 2 millimetres. This experience again demonstrated the importance of foresight in anticipating challenges and allocating time efficiently to address them.
In the end, the groundwork laid before the exhibition paid off. Preparing for the transport of the space and planning a quick setup ensured the robot operated successfully during the event.
Impact
Throughout the show, several people had started to post onto Tiktok and Instagram. We posted our own video below.
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Looking back with all the knowledge I have now, it is safe to say that I could have navigated through the roadblocks and difficulties more smoothly. However, the ‘wow factor' this robot had on the exhibition was immense. There were times that a large crowd had congregated around the robot arm's enclosure and caused pedestrian traffic to stall. We were certainly the talk of the show and we are very proud of it.