Background

The project involved designing and building a 3-lb Battle Bot to compete in the National Havoc Robot League (NHRL) competition, held in May 2023. The competition is known for its rigorous standards and high level of competition, requiring participants to create robots that are not only robust and powerful but also innovative and strategically designed. Working with one teammate, we aimed to develop a low-weight, hard-hitting robot that could excel in this challenging environment. This report outlines the project's context, the challenges we faced, the solutions we developed, and the results of our efforts.

Problem Statement

The primary challenge assigned was to design and build a competitive 3-lb Battle Bot within a stringent budget of $200. The robot needed to be:

Lightweight yet durable to withstand high-impact battles.
Equipped with effective offensive and defensive mechanisms.
Capable of being manufactured using available resources and technologies.

The key objectives were to ensure that the robot could deliver powerful hits, maintain structural integrity, and stay within the weight and budget constraints.

Solution

Design and Planning

Our solution focused on creating an asymmetrical design with a vertical spinner and a wedge, aimed at maximizing impact and throwing opponents. The design process involved:

Robot Design: Designed a single-tooth vertical spinner weapon, to maximize depth of each hit. Used a wedge to lift opposing robots towards the weapon, and ultimately throw the opposing robot in the air. The body of the robot was made with HDPE plastic to balance the weight of the robot. We also added a semi-cylindrical foam piece at the back to prevent our robot from ever getting stuck on its backside.
CAD Design: Using Autodesk Fusion 360 solid modeling, I designed the robot, allowing us to visualize the robot, simulate its performance using FEA and CoM analysis, and make necessary adjustments before manufacturing.
Material Selection: We chose S7 Steel for the weapon due to its exceptional toughness, shock resistance, and high weight density, critical for high-impact scenarios. For the robot's body, we chose HDPE Plastic due to its lightweight, durability, and machinability. We also used 6061 Aluminum sheet metal, foam, and 3D printed components for miscellaneous parts such as the front wedge, robot backside, and various hubs and spacers.

Manufacturing

The manufacturing process varied for each component:

3D Printing: Used Ultimaker 3D printers to rapidly prototype low-fidelity prototype assemblies to test fit.
Waterjet Machining: Utilizing an OMAX waterjet, we machined the S7 Steel for the weapon and the HDPE Plastic for the body, allowing for tightly toleranced parts to be manufactured accurately.
Laser Cutting: Used a Fablight Laser Cutter to cut aluminum sheet metal components.

Budget Management

Maintaining the project's budget was a critical aspect. Our approach included:

1. Cost-effective Material Selection: We sourced affordable materials consistent with other teams, to save on material costs.

2. Efficient Manufacturing: We used in-house machining capabilities such as the OMAX waterjet and Fablight Laser Cutter to help minimize manufacturing costs.

Conclusion

The project was a great learning experience, even though our robot did not succeed in the competition. We managed to design and build the robot on time and within our $200 budget. The robot’s vertical spinner and wedge design worked well during testing, showing that our ideas and manufacturing techniques were on the right track. However, during the actual competition, we faced electronic failures and problems with the remote controller, which prevented our robot from performing as planned.

3 lb. Battlebot Competition - "Firestarter"