Mechanical System
Overview
Much of Onyx is based on Græy (our 2020-2025 AUV), and much of Græy is based on Orange (our 2019-2020 AUV), so we continued to use 80/20 extrusions for the base construction of the frame. Utilizing 80/20 extrusions provides us with better modularity with respect to the construction of our AUVs. While 80/20 extrusions may not be as compact as alternate options, like CNC waterjet parts, their quick assembly and cost efficiency allowed us to deliver within a tight schedule. Furthermore, this system’s modularity allowed us to rapidly make crucial modifications. For example, we fixed an unequally distributed buoyancy on Græy by shifting the positions of its two enclosures. With the 80/20 build system, we can use our manufacturing method of 3D printing to create accurately and properly toleranced parts that interface well.
Torpedo Launcher
The torpedo launcher is powered by a single Gobilda torque servo encased in a Blue Trail Engineering Underwater SER-2000 Servo Enclosure. The servo turns a pair of offset cams which opens the sear gates and releases the stored energy of a extension spring into the torpedos. Magnets embedded in the torpeedos and the torpedo tubes prevent premature deployment of the torpedos.
Gripper
The claw consists of the Newton Subsea ROV gripper base actuator with modified jaws fabricated through fused deposition modeling (FDM). The jaws were designed according to the game piece geometries, the gripper is mounted on a linear slide rail with a magnetic quick-release match and will be deployed below the sub at the beginning of each run.
Marker Dropper
We began exploring different design options for the marker dropper by creating a trade study of different designs. Doing so allowed us to rank each design's attributes and select the most optimal design to go with. Our requirements for the marker dropper were to be able to drop two markers separately with only one servo while reducing the footprint as much as possible. We went with the Kyutech Kyubic design due to its weight, minimal size, fabrication cost and reliability. Our first design implemented a 2000 Series Dual Mode Servo, control arm and barrel that holds two spherical markers.
Our design needs to function underwater so we used the Blue Trail Engineering Underwater SER-2000 Servo Enclosure. We used 3D printing to complete rapid prototyping initiatives to iterate and improve our design. We created dry and water unit tests using Arduino for performance verification.
DVL Enclosure
The DVL (Doppler Velocity Logger) was a late addition that was provided by Alan Kenny and his professional engineering team at Kenautics, Inc around March 2023 nearly 2 months before competition. The team explored manufacturability feasibility as well as implemented simulation analysis to risk reduce and verify our design assumptions.
