All components on the Proteus mount to a single frame (A). Above the frame is the electronics hull. Below the frame to each side are battery pods (B). Four thrusters (C) are mounted on each side of the frame. Underwater cables are routed along the insides of the frame and panel fairings (D) serve both as an aesthetic as well as physical enclosure. Below the frame are four support skids (E). All structural components are built using 6061 or 6063 aluminum, finished with a black anodization.

 

 Frame

The box frame is welded using 3/4" wide square aluminum tubing with 1/16" thick walls. Along each of the 4 long bars are mounting holes spaced at 1/2" increments. This mounting system allows precise positioning of each element, be it hull, sensor, or thruster. The welded aluminum frame is also strong enough to withstand any torque from the thrusters.

Underwater Cables

Seacon's Hummer line of connectors and cables form the bulk of Proteus' underwater cabling. Hummers' small form factor not only reduces cable mass, but also allows for a greater number of external connections. The only exceptions are the power lines which use Seacon's more rugged Micro Wet-Con series instead.

Two pod holders are suspended from the bottom of the frame. A rail along the bottom of the holder guides the battery pod in along the correct alignment. A rear latch locks into place, as internal padding ensures the pod is firmly in place. To remove the pod, the latch is popped open and a single connector disconnected. This physical configuration allows the battery pods to be quickly and safely inserted and extracted. Refer to the power section for details.

Thrusters

Each thruster is mounted using a custom bracket. Two vertical thrusters control pitch and depth while the two horizontal thrusters control heading and forward speed. This thruster configuration has proven successful for us in the past. The four degrees of freedom (yaw, surge, pitch, and heave) are enough for the vehicle to complete all competition tasks, including hovering. The simple geometry reduces complexity in the control algorithm.

Skids

Instead of building a separate stand for the vehicle while it's out of the water, four triangular skids are built directly onto the frame. Not only are the stands functional, they also protect the vehicle from inadvertent damage. Being able to lift the vehicle out of the water and immediately set it down on any flat surface is another way to make the debugging and testing process faster. The small triangular configuration was chosen over full skids because they are lighter and leave a clear field of view for the downward facing sensors.