Brainstorming

           The design challenges can be sorted according to subsystems. Each subsystem has its own nuances to keep in mind for optimal function. The main subsystems of the ROV are buoyancy/architecture, robotic arm, and propulsion.

Buoyancy/Architecture

            In terms of buoyancy, the goal for the ROV is to be very close to neutrally buoyant. Sometimes, ROV’s are slightly heavier or lighter than neutrally buoyant according to user preferences. When the ROV is close to neutrally buoyant, the propulsion system is more effective. Buoyancy also determines how much real payload an ROV can carry (“Buoyancy”).

            The goal of the architecture is to make sure that each subsystem can operate seamlessly and independently. Absolutely essential to the design of the architecture is cable management. If the cables interfere with or get caught in any other subsystem, the ROV will be very difficult to operate. Strategic placement of cables needs to be planned.

            I hypothesize that it would be best to build the ROV slightly heavier than neutrally buoyant. This, way, there will always be a downward force acting on the ROV, and a propulsion system to move down the water column will be unnecessary. On the other hand, this design requires constant upward propulsion to avoid moving down the water column constantly.

Robotic Arm

            The key the robotic arm is to use the simplest design possible that can get the job done. Because of the largely uncertain nature of the marine environment, complexity can often result in problems with reliability, operation, and maintenance (ROV Applications- Design- Manipulators”). It is important that the orientation of the arm can be manipulated as to get the best leverage and angle of approach on the object that is trying to be lifted. Generally, robotic appendages have two sets of prongs opposite each other to fully encompass the object that is being gripped. It is important that the grip is tight on the object so that it is not dropped while being transported.

Propulsion

            The propulsion system will largely depend on the size of the ROV. The bigger the ROV, the more power required to make it move. There is a tradeoff with feedback effects between propulsion and the other subsystems, because the larger the other subsystems are, the more power required, which means a larger propulsion system, which means even more power required. The ultimate goal of a propulsion system is a high “thrust to physical size and power input ratio.” Also, conditions of use for a propulsion system built for a specific client need to be taken into account because a more powerful propulsion system is needed to operate in stronger sea currents (“ROV Applications- Design- Propulsion”).

            As our competition will take place in a controlled pool environment, a heavy-duty propulsion system is unnecessary. However, it is still important to take into account the thrust to physical size and power input ratio because this will determine how powerful the propulsion system will be given the size of the ROV. Reversible propellers will be an important material to have because they allow the solution to only need propellers on one side to move in both directions.