Enclosure Assembly (Vision Module)

Additional Enclosures

/images/docs2_html_b0bc812887a518b9.png The main consideration when choosing the enclosure sizes and their configurations would be the hardware size constraint for electronics. Through CAD modeling and having the dimensions of the electronics sketched in the software, the right configuration of enclosures for the payload skid could be designed before the physical prototyping begins.

Figure A shows a series of 3-inch enclosures mounted side by side that demonstrates the mounting space available on the payload skid.

The choice of edge computer, based on their size and processing power, was between a Jetson Orin NX and Jetson AGX Orin. However, the AGX Orin could fit 5-inch enclosure size, in which the only possible configuration for mounting the 5-inch enclosure onto the payload skid is shown in Figure B. This configuration in Figure B would prove to be difficult in transporting and placing the ROV flat on the ground as the whole weight of the ROV would be placed onto the 5-inch enclosure, thus prone to topping on either side.

Hence, by scaling down the processing power required for our application to an Orin NX, the size constraint of the edge computer is reduced to fit a 4-inch enclosure and with additional battery in a neighboring 3-inch enclosure supplying power to the electronic system , which results in the final configuration shown in Figure C.

Dynamic Buoyancy Foam Configurations

/images/docs2_html_440a756ea34daffa.png /images/docs2_html_1306cd1e1b312ec8.png There is a need for a method to dynamically adjust the ROV’s buoyancy level to neutrally leveled, due to the weight distribution of the components on the ROV and the densities of the water in the open water test sites, be it saltwater in the sea or chlorinated water in swimming pool. Referring to the CAD model, the difference in volume of compressed air stored in the sealed 3-inch and 4-inch enclosures would result in an uneven distribution of buoyancy level on both sides, with the side of 4-inch enclosure being more buoyant. Hence, additional buoyancy foams were mounted on the side of the 3-inch enclosures to balance out the buoyancy level.

The buoyancy foams were fabricated from the Subsea Buoyancy Foam: R-3312, Blue Robotics that has similar design functionality to the stainless-steel ballast weight as well. With the flexibility to mount the buoyancy foam blocks onto the mounting holes of the payload skid bottom panel in any configurations, the buoyancy level of either side of the ROV could be adjusted to achieve the stability of the ROV during maneuvering.