Combat Robotics - Jaden Zhang

Designing and building competitive 1lb (antweight) and 3lb (beetleweight) battle bots is the core of combat robotics at the University of Toronto Robotics Association (UTRA) Combat subdivision, from computer aided modelling, 3D printing, manual machining, electronics soldering and radio configuration.

With the goal of doing as much physical (and psychological) harm to opposing robots in the ring, we compete mutliple times annually at Botbrawl (Canada) and National Havoc Robot League [NHRL] (United States), with a lineup of unique robots, a couple of which I had a hand in designing/manufacturing.

Key Skills: Radio Transmitter/Receiver Configuration, LiPo Battery Management, Material Selection, Robotics Assembly/Design, 3D Print-Compatible CADing

3LB BOT - ATLAS V3

April 2025 - Present

With a ruleset change heavily unfavourable to Atlas V2, we pivoted this year to a new, more compact and efficient 3lb bot design with wheels instead of shufflers, while still retaining the core design philsophies of its ancestor. Currently living in Solidworks, we aim to have a fully functional and troubleshooted robot by mid Janurary 2026.

In collaboration with: Indesh Vijayanand, Jonah Kittmer, Lucas Skotiniotis, Angela Mou, under UTRA Combat

Achieved a more than 20% mass reduction in compliance with rules, reducing horizontal and vertical profile by more than 30% and 15%, respectively
Full part and assembly design CAD in Solidworks, including fasteners and electornics placeholders, considering manufacturability, budgeting, and operational ability
Material assignment for function and weight, including consideration of Aluminium 6061, Titanium (Grade 4), TPU (95A), PLA+ (Higher strength PLA), Carbon-fibre (Water-jet outsourced), and reinforced Nylon-6 (Carbon Fibre/Glass Fibre reinforced Nylon)
Electronics layout consideration, including LiPo battery, finalizing on 2x 4s 600mAh batteries for optimal capacity (~5 minutes, or 1 round), and sufficient current

One of our newer designs, the angular shell more effectively deflects impacts from other bots, while also lowering center of mass to minimize the chance of being flipped upside down. The steel weapon's counterweight, typically an idle protrusion in most designs, has also been edited to be a vertical brace, providing vertical cover when the shell is spinning.

Affectionately named 'Cake Atlas' for its shell assembly layout, this shell design is inherited from the previous iteration, providing vertical modularity for the steel weapon to be at the very bottom or between the white UHMW shell spacers. Compared to an angular design, it has a smaller footprint, though is quite susceptible to being overturned in competition.

A rough collage of points and images of reference used to construct ATLAS V3 in the brainstorming phase, mainly to do with shell design as it is the core of ATLAS' functionality.

1LB BOT - POPOFF

January 2025 - May 2025

A compact construction of kinetic energy, this bot fights in the 1lb weight class with a vertical spinning piece of hardened steel that just happens to make up more than 50% of its total mass. Due to this construction, the TPU body/housing needs to as compact and minimal as possible, with wheels that can handle the overwhelming gyroscopic effects induced by the large spinning mass.

In collaboration with: Leo Ping

General maintenance and iteration of bot design, from wheel construction/sizing and TPU housing adjustments
Heavy troubleshooting of radio receiver and transmitter pair (FS2a and FS-i6 Flysky) for signal interference, distance issues, and mix/channel configurations to maintain connection and responsiveness from across the box
4s LiPo battery troubleshooting and maintenance, including soldering cell connections and manipulating LiPo charger configurations to revive batteries from under functional minimum cell voltage (< 3.0V) to maintain LiPo rechargability and current output
Live troubleshooting and repairs during competitions, including Dremel work on the housing and resoldering cut/damaged wires during fights, leading to a top 10 finish in its first competition and a Best Rookie community award

Popoff before the competition, sporting heavily iterated wheels, cast with Vytaflex rubber for extra grip.

Troubleshooting and pairing radio transmitter and receivers (FS2a and FS-i6 Flysky), as well as adjusting/protecting antena.

Soldering and tracking progress when troubleshooting the 4s LiPo battery. LiPo charger was switched to NiCd charge to bypass balance charging, allow the 4s (which effectively became a 3s temporarily due to a dead cell) to be jumpstarted.

An quick excerpt from the last fight Popoff was in early 2025. One wheel axle was a bit damaged going into the round, however. The self right mechanism is also shown in this clip - spin up the weapon and hit the wall.

Pre-battle photos with some other bots at the competition! Also won the Best Rookie community voted award.

3LB BOT - ATLAS v2

September 2024 - June 2025

This 4.5lb full shell spinner fights in the 3lb weight class due to the weight bonus earned by its distinctive movement mechanism: not wheels, but a 4-foot shuffler set. A timing belt driven outter shell is outfitted with UHMW uprights and a hardened steel 2-tooth weapon allows ATLAS v2 to use its rotating shell as both an offensive tool and a defensive mechanism by deflection. Having competed in more than two years' worth of competition and achieving podium multiple times, v2 is a proven effective design.

In collaboration with: Indesh Vijayanand, Jonah Kittmer, Lucas Skotiniotis, Leo Ping, Giacomo Cristiano under UTRA Combat

Lightened 3D printed components by more than 30%, only decreasing strength by only ~15% while having sufficient safety factor
Robot pit crew during competitions to ready for 5-10 minute turnaround - applying Locktite/accelerant, soldering, bodywork fixes, and battery management of up for the entire team
Implementation of varied movement mechanisms, including a vibration-driven bristle drive, using small slanted ABS extrusions on the bottom
Basic manual machining with aluminium alloys, titanium rods, and hardened steel

The 4.5lb shell spinner, shuffler ATLAS. A compact design that uses its shell as both a method of prying off metal from others and protecting its own internals.

From left to right, the shell by itself (with its safety foam covers), the whole battle-ready robot (with its weapon safety lock), and the shuffler assembly being checked for debris.

One of the more fun-to-watch fights from ATLAS v2's history. Going up against one of the best vertical spinner bots, 'Orders from the House', this fight resulted in multiple gouges in the bulletproof plexiglass of the surrounding cage. Unfortunately, we did lose this round by our battery ejecting itself due to container failure. This caused an iteration of the battery box (shown in the first image). Botbrawl - Robodrome December 2024, Hamilton, Ontario.

A high level breakdown of the dual CAM shuffler mechanism

Sync and directional testing of the shuffler mechanism during a competition. In between rounds, it is our responsbility to fix and troubleshoot our bots as much as possible to be ready for the next.

First test of the self-righter in our DIY test box. It functions since when upside down, the shell does not spin - the internals and the titanium shaft does - therefore, by attaching the slanted aluminium piece on top rigid to the shaft, the bot is able to self right.

On the left, a damaged shell with frayed CF. On the right, a lineup of all of the University of Toronto battle bots in February 2025, Norwalk, New York.