On Thursday last week a team of students who work in MCIC's Makerspace won first prize in the UNSW Mechatronics Society's inaugural Sumobot Challenge.

All semester 33 teams have been working hard to design small, autonomous robots which competed against each other in an arena modelled on those used in Sumo wrestling. The robot that managed to force it's opponent from the arena won the round.

After their win in the finals, we interviewed Team Lead, Dom to find out more about the team's winning design.

 

Hey Dom! Can you explain the design of your winning robot?

While other robots used a tray feature on the front to scoop and flip opponents, our robot was specifically designed to be as good at pushing as possible. This meant that grippy wheels and as much mass as possible where needed, and hence we made custom aluminium wheels with an extra grippy cast silicone tread.

The wheels were placed at the back so that when pushing another robot, the wheels would be pressed into the ground, resulting in a small increase in traction. In order to prevent other robots from lifting our front, a small aluminium scoop was added. Two line sensors were attached in the front right and left corners of the robot, to allow for the earliest possible detection of the edge and its orientation. Together these features helped in getting small advantages over our opponents, and with some strategy in the code,  our robot could always target our opponent's weaknesses, or use raw pushing power to bulldoze them out of the field.

 

A lot of teams chose to build the body from 3D printed plastic or other solid materials. Why you choose to make it out of wood, and why the intricate design?

The reason for using plywood is it is readily available and easily cut and assembled into a robot frame. Using CAD we could model all the individual robot panels to fit together perfectly and house all other components. It is also quite lightweight, which was a necessary in order to be under the weight limit, while still being strong enough to withstand the forces endured during competition.

 

What Makerspace stuff did you use to help you make it?

The most used tool in the Makerspace was the laser cutter. It did all the cutting for the robot frame, as well as the mould for the silicone tyres. The CNC mill was used to create our wheels, which was not necessary, however it was a fun exercise. The 3D printers were used to print small adapters for our wheels to our motor shaft, and finally the soldering irons were used solder all electrical connections for the reliable running of the robot. A variety of other hand tools were used to make small modifications to various parts.

 

Who helped out on the project?

The other member of the team, Daniel Huang, came up with most of the concepts for the robot, and CADed the first version of the frame, which was modified to make the final version. A huge thanks goes to Brody Smith, who after seeing our failed attempt at casting our tread using caulk, gave us some proper silicone which could cure in time for competition.

the teams face off

What lessons have you learned?

A number of lessons were learnt throughout the construction of this robot. The first came with the milling of the wheels, which was the most complex milled part I had ever made, and many lessons were learnt in indexing and fixturing of the part. The second was the casting of the tread, which turned out to be very successful on the second attempt, which clearly demonstrated a major difference in the different silicones available.

Dom and Daniel

Lastly, what are you going to do with all that prize money?

Whilst I have not decided what to do yet, the prize money will most likely be reinvested into parts for future robots, or contribute to the expansion of my own set of tools.