Testing and development
Throughout the project we have experimented with a variety of designs and prototypes to arrive at the ideal design for the missions that we have. A good example of this is the actuator that we have designed to balance a platform by rotating a PVC pipe connector. The initial design can be seen below. While this design was able to accomplish the task, it was not efficient because it tended to slip (you can see it in action in the video below). To fix this problem, we designed a different attachment, which ensures that the pipe connector is held from all directions. You can see the new attachment in the ROV's photo in the next section of this post.
Testing the leveling actuator
We have also carried out a variety of tests throughout the project to assess the design of the vehicle itself. These included tests to assess the ability of the electronics housing to withstand pressure underwater and also general tests to assess the maneuverability and propulsion system. Here's a short video that we shot earlier this year of one of these tests.
The Final Product:
After working on it for over 6 months we're finally proud to introduce you to our ROV:
Front view of the ROV
Back view of the ROV
Propulsion and maneuverability
It has 6 thrusters, 4 of which are arranged in a vectored configuration to allow it to move in all directions in the horizontal plane. It has 5 degrees of freedom, which can be easily controlled by the pilot using a joystick.
To ensure that the ROV is easily to control, it should be designed to be neutrally buoyant. This means that, if it left at a certain point under water, it would not sink or float up. To do this, we used foam to offset the weight of the ROV. We also attached foam at intervals throughout the length of the tether to ensure that it is also neutrally buoyant. As a result, the ROV is very easy to control under water.
Foam blocks used to adjust buoyancy
The competition specifies 48 DC Volts as the input to the ROV through the tether. To power our electronics, we used 4 DC-DC converters to convert the 48V down to 12V. These converters were sealed and installed outside the electronics housing to free up space in the housing and to provide cooling to the converters.
DC-DC Converters attached at the bottom of the ROV
During the competition, the pilot cannot see the ROV; therefore, the vision system is critical for the pilot to be able to carry out the mission successfully. The video feed must be of high quality with minimal or no latency. For this we decided to use 5 webcams, mounted at different angles and positions. The cameras are connected to Raspberry Pi, which acts as a webserver to serve the different video feeds. The Raspberry Pi is connected to the pilot's laptop over the network, through an ethernet cable.
The ROV is fitted with a pneumatic system to allow us to control a pneumatic gripper and inflate lift bags. The main advantage of a pneumatic gripper is that, unlike electrical motors, it does not require additional sealing.
This is an overview of our ROV, but we are always happy to talk more about the work we have been doing. If you have any questions, please leave them in the comments below and we will get back to you very soon !