Calypso is a research submarine, capable of reaching the depth of 1000 meters. Her senses are represented by an array of sensors, through which she collects data and sends them to the team on the surface. Her energy comes from a power cable, and data is streamed over an optical cable. We try to make all of the parts ourselves, but due to that not being entirely possible, we get help from numerous high-tech companies.
Designed with inspiration from nature
Calypso consists of two major parts. One of them is the outer shell, that enables the submarine to maneuver smoothly even in moderate underwater currents. The shape itself is inspired by the beautiful manta ray. The design has changed dramatically during the 3 years (image 1, 2 and 3), and at the end we chose the most hydrodynamically shaped hull. The hull is made out of resin infused glass fibers. While in water, it will be flooded from both sides, so there is no need for any extra structural stability. The shell is infused with syntactic foam to ensure neutral buoyancy.
A safe place for all the electronic components
The hard inner shell protects vital parts of the submarine from water and high pressure.It consists of an aluminum tube closed on both sides which houses all of Calypso’s electronic equipment. It is connected directly to the surface through the power supply and data cord. We supply the submarine with 220 AC current which is then converted to 24 V DC. The main challenge was to securely seal the hull to prevent water leakage. Even the smallest hole in the sealing rings or a defect in the weld would cause the hull to flood within seconds. We are very proud of our sealing solutions, especially the underwater penetrators which we designed ourselves.
Underwater hull penetrators
Keeping the water out
In order to connect the underwater thrusters to the electronics insde the inner shell we needed to secure a cable connection from the inner shell to each of the thrusters. Since they have to sustain 100 bars of water pressure, this was not an easy task. We could buy the industrial grade penetrators, but instead we decided to make them ourselves. How hard could it be? :) And after our 20th model failed we found out that it is quite hard, but we didn't give up. After 12 months of research and continuous fails the first prototype was finished and after that it just got better. We are proud to present our hull penetrators: with a depth rating of 2500 meters. We tested them in salt water at 250 bars of pressure, for 48 hours straight, and they work like a charm. Not a drop came through.
Propulsion and power systems
Calypso will be propelled by 6 underwater thrusters with a depth rating of 1000 meters (100 bars of pressure). The positioning of the thrusters enables Calypso to perform complex underwater maneuvers, and ensures a full 3D mobility. We managed to write the code for our drivers, and now we can drive the motors at low speeds which is otherwise not possible with the common drivers. Controlling the motors at low speeds gives us better control and handling. Through the supply cable we will provide 220V of alternating current (AC), which is then transformed to 24V of direct current (DC) by a switching station inside the inner hull. The switching station than provides current to every other electronic system except for the power supply of the underwater reflectors. They work independently from other systems. That way we can minimize power fluctuations in the power grid inside the submarine.!----
Calypso’s artificial intelligence
80 000 lines of code, three controlling systems and one goal. To make a reliable controlling system. It wouldn't be possible without a dedicated team of programmers, who put in countless hours of their free time to develop it. Motor control, position control, power control and monitoring the environment in the inside hull are just a few pieces of the puzzle we call the artificial intelligence. Most of the functions are controlled by NI myRIO platform and the Beagle Board. We actually tested a wide array of available microcontrollers, but chose the two that had the most stable I2C protocol. The reason we chose two different systems is the redundancy. Both controllers are capable of controlling the submarine independently from each other. That is especially important if something goes wrong, and we need to quickly surface the submarine.
Seeing the world below
Calypso uses 2 IP cameras to see. They can both stream in full HD resolution, which will enable us to see the hidden world underwater. They are connected to a gigabit switch, which will transmit the data to surface in real time. We know that the deep is dark, so each camera has a underwater LED light. We made every single one of the camera cases ourselves, and tested them at a pressure of 100 bars. We used our own hull penetrators and they work perfectly, just as they did with the motor connections. Prepare for a lot of underwater footage!