Every year in the BattleBots subteam of RoboJackets, newly recruited RoboJackets form into small teams to work together to design and build 3lb combat robots. Last year, instead of going to Motorama and building standard 3lb combat robots, the new members built lighter robots using a limited set of materials and only competed against themselves internally, but this year the typical 3lb program is back.
During the design process, the robot designs are reviewed twice. At the first design review, the goal is to catch basic flaws in the designs that the teams can address before the second design review. The second design review has one goal: approving the designs for manufacture. Last month, the 3lbers had the second and last design review and will be moving into manufacturing their robots in the spring semester. What was new this year was that the alumni association provided an alumnus with experience in industry in addition to RoboJackets (Jonathan Spalten, also the author of this article) to provide more detailed and experienced feedback than the members of the team themselves could provide. The teams will be competing at Motorama 2022 in Harrisburg Pennsylvania in February. Here’s a brief description of each of the six robots that are being designed, along with CAD screenshots.
First up is Blasphemi, a ring spinner. Blasphemi is being designed and built by Daniel Vail, Lucas McCarty, Madison Debruin, German Ortega, Andrew Fugett, and Chinonye Mbeledogu. Ring spinners are challenging robot types, especially in the smaller weight classes where every ounce counts. The typical challenges with making ring spinners work is properly mounting the ring and ensuring it can take hits during a match, including the forces that come from its own hits.
Blasphemi’s solution to this challenge is a set of three rollers that are specifically designed to fit into a machined profile on the inside of the ring, shown above. With properly machined components, this will ensure the ring is always exactly where it is supposed to be.
Next is Insaniti, a vertical spinner. Insaniti is being built by Siva Appana, Shreya Terala, Taha Haveliwala, Xiang Li, Jun Hao and Galen Tunnicliffe. As a horizontal spinner, Insaniti has a lot of potential to launch opposing robots straight up into the air, but also runs the risk of being flipped upside down, causing their weapon to hit the floor and cause uncontrolled movement. To prevent this, Insaniti has a pair of tall “dog ears” that protrude above their weapon’s effective range and enable them to function normally even when upside down.
Not shown in the main CAD view are pieces of HDPE armor with a unique bent shape to help protect their foam wheels. The team plans to bend thin 1/16” HDPE into the above shape. This armor protects their wheels by deflecting enemy attacks due to the tension stored in the HDPE. They plan to add this armor after shedding some weight from their chassis.
Next is Papajonni, a horizontal spinner with a twist. Most horizontal spinners use a weapon motor, a belt, and two pulleys to transmit torque between the weapon motor and the weapon itself, but Papajonni is planning to follow the less common path: building their weapon around the motor. The team plans to buy an off-the-shelf motor that they will take apart and rebuild inside their weapon. Papajonni is being designed and built by Arvind Mahadevan, Bella Brunner, Alex Mitchell, Noah Frank, Greyson Lovett, Elijah Vazquez, and Connor Erickson.
The team has been hard at work experimenting and taking apart stock motors to prototype their manufacturing process, but the team also has a backup design using a belt in case they aren’t able to make their first idea work in time. Another interesting feature of this robot is that instead of the more typical aluminum sidewalls, the team plans to use Markforged Onyx (a carbon-fiber filled nylon 3D print filament) to protect their electronics.
Next is RickandMorti, another horizontal spinner. RickandMorti is being built by Jathin Gadiparthi, AJ Abrigo, Sierra Yim, Chanh Ngugyen, Jihan Park, and Hyejee Chang. RickandMorti represents the more typical horizontal spinner that RoboJackets members build for 3lb combat robotics, but is also a solidly designed robot. The main challenge for the team is cutting their weight down by about 1/4 of a pound to leave enough weight for wires. The team is using a hexagonal cut out pattern to save weight in their top and bottom plates.
Additionally, if weight allows, the team plans to add thin HDPE armor, similar to Insaniti. This armor design has a long history of protecting 3lber wheels from enemy tool steel, and we expect it to do the same this time around.
The penultimate robot is Singulariti, a vertical spinner with a four wheeled brushless-motor drive. Singulariti is being designed and built by Peter Zhang, Joe Baldino, Kaden Knudsen, Kyle Liu, Casper Corbin, Michelle Zhang, Patrick Villarreal, Sophia Lin, and Stephen Britten. Singulariti is unique among RoboJackets’ 3lb vertical bar spinners for its four wheel drive and the steel plow placed on the front of the robot to guide its opponents to its weapon. This robot also uses Onyx in its construction, primarily in the drive motor mounts.
The drive motors transmit torque to each pair of wheels using timing belts. All the components shown, except the motor and rubber on the outside of the wheels, are planned to be 3D printed using Onyx. This design is intended to provide better traction on the combat arena floor and enable the robot to better control the matches it competes in.
Last but not least is Velociti, a third horizontal spinner. Velociti is being designed and built by Austin Graves, Jacques Wang, Divyam Kumar, Alexander Torjak, Hanran Wu, Zixiao Yang, and Evan Strakes. Velociti has much in common with many other horizontal spinners, including its weapon shape and bent HDPE armor. Velociti uses a belt, but instead of aligning the belt along the length of the robot, the weapon motor is offset to the side, enabling the team to better distribute their electronics inside the chassis.
One of the difficulties in operating a horizontal bar spinner is servicing it between matches, in particular replacing the battery. In most horizontal bar spinners, the top or bottom plate must be removed, and this means the weapon shaft also has to be removed. This means the belt will have to be re-tensioned before the robot can go into combat. Instead of this approach to service, Velociti’s back plate can be removed, enabling the team to replace the battery without having to reassemble the weapon mounting system between every match.
As you can see, all the 3lb teams have made good progress, and we’re excited to see the robots come to life and compete at Motorama. We also asked Zach Slaton, the current 3lber program lead, his thoughts on how the program is going so far:
The 3lb program has gone extremely smoothly this semester as it transitions from an online, plastic robot year back to the standard in-person metal robot program. … Each team has had excellent member retention and have each designed functional and good-looking robots that I have high hopes for at Motorama in February. Two bots in particular, Papajonni and Singulariti, are pushing the envelope with innovative new designs previously unseen in the 3lb program, which have a chance to impart some valuable engineering experience into their team members. After two sets of productive design reviews, each bot should have most of their problems identified and ironed out soon, which should lead to a successful build season in the spring semester.