Submarine Design

Cameras

The submarine has a total of 5 cameras. There are three cameras that are on gimbals allowing for them to look around. These include a forward facing camera, a downward facing camera, and a rear facing camera to watch the fiber optic tether in order to prevent it from getting tangeled. Then there is a DSLR Camera for capturing high quality video. The last camera is mounted at the end of the robot arm in order to see what is being grabbed.

5-Axis Robot Arm

The submarine has a 5-axis robot arm for picking up and manipulating objects on the sea floor. It has a reach of 24 in while lifting up to 11 lbs. More details on the Robot Arm page.

Weight Shifter

The weight shifter moves two large stainless steel weights forward and aft in order to control the submarines attitude when lifting heavy objects with the robot arm. This assembly needs some minor redesign to reduce the belt friction (by adding ball bearings), because the current friction is slightly to high and occasion is overloaded.

Frame & Skin

The has a skin (yellow 3D printed parts along with black semi transparent acrylic panels. This skin is NOT water tight, the internals are intended to flood with water. There are many large holes (with screens) to ensure it does flood with water and also entirely drain. The purpose of the skin is for hydrodynamics, to reduce the drag. The frame is what supports the entire submarine when being lifted from the water, sitting on the ground, or being pulled up from the bottom with the tether (All three cases have been analyzed with FEA).

Batteries

There are two cylindrical pressure vessels with a total of 3.5 kwh of batteries. All the power electronics are located in the Large Camera Vessel which includes the BMS, buck converts and ESCs.

Ballast Tank

The ballast tank is a tank that can be pump full of water or drained of water in order increase/decrease the mass of the submarine to alter its buoyancy. This allows the submarine to be calibrated to be neutrally buoyant even when new equipment is added or removed. Additionally with the addition of a pump this can be used to ascend a descend (this is still a WIP).

Communications (Fiber optic tether)

Water is rather difficult to send wireless signals through especially at high throughputs, therefore a tether is used to connect the submarine to a computer on the surface. This submarine was designed to go to a depth of 1400 ft which is far to long for ethernet any high speed copper cable, therefore fiber optics was the clear choice. The fiber optic cable used is a armored fiber optic cable with a foam like insulation making neutrally buoyant in water to prevent burdening the submarine.

Electronic Enclosure

This is the largest pressure vessel on the submarine with inside diameter of 8 in and a length of 20 in. This pressure vessel contains all the control electronics including a raspberry PI computer, a fiber optic transceiver, a custom micro controller PCB and some power electronics. The vast majority of the room in the electronics enclosure is unused and intended for future additions to the submarine.

Large Camera Vessel Enclosure

This pressure vessel contains a DSLR Camera for taking high quality video as well as power electronics include a BMS (battery management system), buck converters for reducing the batteries voltage for each system, and ESCs that control the thrusters. Due to all the power electronics heat output they are water cooled.

Weight Drop

The weight drop has a weight that is held on a by a electromagnet. If the power fails for some reason the weight will drop from the submarine and causes the submarine to surface. This is a safety feature. This is an additional safety feature on top of being able to lift the entire submarine by the tether.