Progress Report - Mechanical Design (01/18/2012)

The vehicle will undergo a watertight test this afternoon. If there is any leakage in the hull or any of the two camera enclosures, more silicone caulking will be added. Hopefully this will not be necessary, however, so that we can hand the enclosures over to Ryan for testing with the web cameras inside. Also, new mounting plates were made for the bottom thruster and the marker dropper mechanism. The heads of the screws for the bottom acrylic supports were intersecting into the locations of the clearance holes in the original thruster mounting plate. The mounting holes were simply migrated inward toward the center in the new mounting plate--a simple adjustment. For the marker dropper mounting bracket, I simply cut an aluminum angle bracket to 1" x 1" x 3.75" dimensions, drilled a few holes, and attached it to the marker dropper and frame. Furthermore, I designed individual identical mounting plates for each of the four solenoid valves. I decided on revised locations to mount the solenoid valves, as well as the four-way split adapter for the gas lines. The new scheme will be very efficient (i.e. more direct), aesthetically appealing, and also distributes the mass of these valves symmetrically throughout the vehicle, thus maintaining proper balance. I also ordered a CO2 tank, a lightweight pressure regulator, and a check valve (if it works properly, I will purchase two more). So, the CO2 distribution system should be ready for testing toward the end of this week. Once the screws and T-slot nuts arrive (this evening), the solenoid valves will be mounted to their corresponding plates, the plates will be attached to the 80/20 frame, and I will start connecting the nylon gas lines (tubing) to the push-to-connect adapters. During this stage, I will also cut the tubing to size so that there won't be excess tubing hanging off the vehicle. When the CO2 tank and pressure regulator arrive, the network can be completed and preliminary tests can ensue. Thereafter, I will make interface circuits (low side drive BJT) to enable easy actuation of the solenoid valves with a micro controller. These tests will likely be done with a Dragon Board due to familiarity. The SEACON connectors should arrive shortly as well. Once they arrive, they will be installed in the inner end caps of both the hull and camera enclosures. The four SBT150 thrusters can then be potted using epoxy, and the leads of all the thrusters can be carefully soldered to the corresponding leads of the male cables. The interface will be protected using shrink wrap at a minimum.

                                -Eric Sloan (ME Project Manager - AUVSI Robosub Competition)