Final Design

Team Final Design

The final design of the Autonomous Underwater Vehicle (AUV) consists of 4 main body components; 1) a hollow, water-tight aluminum cylinder, 2) two thrusters on either lateral side on the back of the AUV, 3) two control surfaces (fins) on either lateral side mounted to the bottom of the cylinder, and 4) weight compartment on the bottom of the cylinder placed behind the control surfaces.

1. A hollow aluminum cylinder sealed off by double O-ring seals on both openings serves as a water-tight enclosure to house the electronics bay consisting of batteries, a Raspberry Pi4, a BNO-055 accelerometer, and electronic speed controllers (ESC’s). Cable penetrators in each O-ring end cap allows external cables from thrusters, servos, and sensors to protrude through a watertight seal. An optically clear acrylic dome placed on the front end houses a camera.

2. Two Hydromea DiskDrive-50 hubless thrusters provide forward thrust for the AUV. Thrusters are mounted using custom 3D-printed mounts with built in ducts to allow proper fluid-flow for thrusters. Cables from thrusters are routed towards the back end of the body and enter the watertight enclosure through cable-penetrators. Thrusters are rotated inwards such that articulating the speeds of the individual thrusters results in yaw motion. Running thrusters at the same speed results in pure forward translation.

3. Two fins are placed at a dihedral angle to the body and actuated using ROVmaker steel-gear underwater servos. Servos are mounted using a custom 3D-printed mount attached to the belly of the main body. Fins are rotated up and down to induce pitch and roll movements of the AUV.
   
   

4. The AUV is designed to operate with a slightly positive buoyancy, which can be tuned by adjusting the weights in the weight compartment. In case of emergency (power loss, electronics failure, etc.) propulsion is cut and the AUV rises to the surfaces. When operating normally the slight positive buoyancy is controlled with the fins and thrusters.

 Hardware Performance Summary

1. Turning Radius observed is less than 1 meter.

2. The Sealion’s camera and Raspberry Pi 4B enable it to detect an object and track it.

3. The Sealion is capable of moving forward, turning, and ascending/descending.

4. The Sealion takes a picture every 5 seconds if it detects an object.