Rationale

The catamaran design of solution 1 takes its form from the catamaran sailboat design. A multihull design joined by a structure creates the general frame of the vehicle. On the surface of the water, the catamaran design arguably offers the best function, considering that it provides speed, stability and large capacity. The following design is 18 inches long, 12 inches wide and 6 inches tall. The design calls for the two hulls to be constructed with a welded aluminum boxes that is 18 inches long, 4 inches wide and 6 inches tall. The joining structure is a flat high density polyethylene board that will be attached to the two hulls to create the catamaran design. Offering a relatively compact size, the design would be able to maneuver around the pool with out much concern for interfering with the features in the pool. Additionally, the balanced design ensures that there won't be tilting towards one axis. Furthermore, the layout allows for multiple thrusters to be mounted for horizontal propulsion, as well as vertical propulsion. Overall, the only concern is that the buoyancy is on the bottom, which shifts the center of gravity further up.

Design 2, which is basically an aluminum box on two plastic skids offers a great range of options to effectively accomplish the goals. The initial rationale behind the catamaran design and this design is the fact that the ROV would be able to hover over the HUGO tower. However, this design shows more potential to out perform the catamaran design because the open, unobstructed area is more "open". Other pros include the fact that the buoyancy is located near the top and the design is relatively compact, allowing the ROV to maneuver around the pool efficiently. Furthermore, the skids are an excellent mechanism to stabilize the ROV without using a large footprint, when it needs to rest on the pool floor. Nevertheless there are concerns, one of which is the aluminum box, which may cause a problem when constructing due to the limited construction resources - lack of TIG welding equipment. Additionally, the design needs to account for thruster positioning granted there is space to have multiple horizontal and vertical thrusters. Another issue is the skids, which might need to be weighed down with additional weights in order to create a neutrally buoyant system. By and large, the skid design appears to be the top candidate as it seems to have the greatest potential to meet the specifications and complete the four tasks effectively.

The last design takes my own input and places them into conventional homemade ROV designs. The "Box" design utilizes PVC piping, which is a common material in homemade ROVs. With a ballast tank for buoyancy situated on the top, and much of the weight being consolidated towards the bottom half, the 24 inch long, 12 inch wide, and 9 inch tall box is designed to be quite stable. In addition, the simple piping not only offers an easy build but also provides the necessary buoyancy to ensure that the ROV will remain neutrally buoyant. For the most part, the design takes into account the specifications, such as having the ability to move in all directions, being portable enough to be carried and launched by the mission team, and having the ability to attach thrusters, as well as cameras, a claw, thermometer, and hydrophone. However, the use of PVC as the vehicle structure limits the ability to maneuver over objects in situations such as the HUGO tower. Additionally, though the design is portable, it might create for a difficult situation when retrieving the crustaceans in the tunnel. Though the design offers many basic functions that are designed according to the specifications, some of the disadvantages, especially the inability to maneuver over the HUGO tower make the "Box" an unworthy candidate compared to the two other designs.

Research

            In order to fully understand the background of ROV design for a fully functioning ROV that is to perform a checklist of tasks in a chlorinated, fresh water pool for the 2011 MATES ROV Competition, some research needs to be completed.

ROV:

A Remotely Operated Underwater Vehicle (ROV) is fundamentally an underwater robot that is controlled by an operator that is independent of the vehicle, from the surface that allows the operator to remain out of harm’s way while the ROV works in the hazardous environment below. The total ROV system is comprised of the vehicle, control, umbilical cord (tether), and power supplies. Basic features on an ROV include: thrusters, cameras, various sensors and/or tools. ROVs can vary in size depending on the work, from small vehicles for simple observation up to complex work systems, which can have several manipulators, cameras, tools, and other equipment.  

AUV:

An Autonomous Underwater Vehicle is a computer-controlled system that operates underwater. They lack any connection to the operator, considering that they are self-guiding and self-powered, unlike an ROV, which is tethered. Since the inception of the first AUV, they have advanced greatly. From simple movement similar to a torpedo, AUVs are now capable of gliding from the sea surface to ocean depths, and back. Others can stop, hover, and move like blimps or helicopters do through the air. And resembling the functions of ROVs, AUVs can be inserted in a multitude of environments, ranging from intertidal waters to the ocean floor. All of these functions can be focused for some tasks. Today, many AUVs are being utilized by the Navy for mine hunting. They are also finding usage in ocean research.

UAV:

Unmanned Aerial Vehicles are remotely operated airplanes that are used in place of sending humans into air for reasons that include: danger, dullness, or dirtiness. Many UAVs are used in military application for reconnaissance or attacks. Controlled from half-way across the country, pilots are able to control the plane in a safe cubicle, away from the warzone. Using bandwidth to exchange data, the pilot is able to send direct and immediate controls to the plane, usually with just a 2 second time delay.

Design:

The ROV system is a highly interrelated group of subsystems that, when functioning together, provides an impressive subsea capability. With many unique designs, there are many things to consider when constructing a functioning ROV, due to its environment, which introduces inherent factors that dictate the operation of the ROV. Because of this highly interdependent relationship, ROV system performance is a delicate balance of design and operational characteristic tradeoffs. The general subsystems of an ROV include: vehicle, tools and sensors, control/display console, electrical power distribution, umbilical and tether cords, and handling system. Thus with all these subsystems, it is understandable to see a small change be magnified across the whole ROV system.