This ambitious design was the first iteration of the club's Seawolf robot. With its rotating thrusters, Seawolf I has a great degree of freedom for movement, able to perform acrobatic maneuvers. It also uses various sensors such as a DVL (doppler velocity logger) and a camera system to aid its navigation.

Mechanical

Seawolf I Rendering

Seawolf I's body is custom-formed from polyethylene with a fiberglass shell to apply uniform drag along the hull. Propelling the AUV are three Seabotix thrusters mounted to waterproof servo motors, this configuration allows the thrusters to pivot while in motion and offers more freedom of movement for the vehicle. To protect the electrical systems, they are encased inside an acrylic tube which is sealed with custom-machined aluminum end caps.

Electronics

Seawolf I utilizes an array of different sensor inputs, this includes a DVL, IMU, cameras, and hydrophones. A custom electronics board was designed as an interface for the sensors and other peripherals. This board also interfaces with the AUV's CPU, a Diamond System's Hercules PC/104 board with an embedded 550MHz Via Eden processor. In addition to the main processor, a TI fixed-point digital signal processor was used to analyze the acoustics data from the hydrophones.

Software

The vehicle runs Linux distribution Slackware 10 as its operating system. Seawolf I's software in written in C++ and uses external software libraries to develop control algorithms, vision processing, and collect data. These libraries include uBLAS, OpenCV, and XSens Motiontracker.

The software is divided into three tiers: Low-level devices, Mid-level subsystems, and High-level control. The Low-Level Devices layer manages the hardware components; the Mid-Level Subsystems layer processes the vision, acoustics, and control data; and the High-level control layer accomplishes missions by directing lower level systems.

Acoustics

Acoustics Board

A custom 4-layer PCB was developed for acoustics navigation. The PCB contains an ADC to capture the hydrophone signal, an SDRAM chip to store data, and a TI DSP to process the data and send pair-wise time delays between each hydrophone. The time delays are then used to triangulate the relative position of the pinger.

Seawolf I

Years Used
2005

Computer
PC/104

Material
Fiberglass shell
Plastic frame

Hull
Acrylic Tube

Weight
> 44 lb

Journal Papers

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