Rationale

The ROV construction must have the capabilities of a standard ROV that allow the overall system to pick-up, move, and place stationed rings on an underwater tower. In this case, the mechanical arm of the ROV must provide the proper capabilities to pick-up and move the plastic rings without dropping the rings or inaccurately placing the rings. To achieve this goal, the design of the ROV’s mechanical arm must be maneuverable, functional, and efficient.  Achievement of this includes the proper construction and attachment of the parts of the mechanical arm to each joint and the ROV itself.

The first alternate solution consists of a very compact design. This design has many advantages due to its ease of move and close joints. This design is made of PVC and metal joints. The material make-up of this design does not give this solution a good rating due to the fact that it affects the buoyancy of the ROV. The largest problem with the first alternate solution lies in the length of the mechanical arm design. The length of the mechanical arm in this design does not give a long reach to the plastic rings placed on the underwater tower causing the efficiency and effectiveness to decrease in rating.

The second alternate solution designed consists of a PVC make-up, a three pronged claw, and two main joints. However, using the second alternate solution reduces the capabilities of the ROV. Using this solution allows the ROV to have more range, better efficiency, and more effective and accurate attachments to the plastic rings. This alternate solution causes uneven buoyancy throughout the ROV due to the PVC make-up.

The third alternate solution gives more responsibility to the ROV driver. This design does not have a joint that allows the arm to move in the left and right motion. This reduces the functionality and efficiency of the ROV. The third alternate solution lacks in length which causes similar problems to the first alternate solution. This alternate solution is made up of a metal make-up. This causes an extremely uneven weight distribution throughout the ROV by placing more than half of the weight on the hull.

The fourth alternate solution takes a different approach on the third alternate solution. Material make-up remains consistent between the third and fourth alternate solutions. The extended length of the fourth alternate solutions in conjunction with the metal make-up of the mechanical arm causes an even larger uneven weight distribution which reduces the capabilities of the ROV. However, the length of the fourth alternate solution extends the reach of the ROV. The lack of a joint giving the mechanical arm a left and right motion decreases the ability of the mechanical arm to pick-up and place the plastic rings efficiently.

The fifth alternate solution consists of a PVC make-up with metal joints and a metal two-pronged claw. The PVC in this design incorporates holes in the design to allow water to flow through the mechanical arm. This allows the mechanical arm to keep more of a buoyant state due to the fact the PVC with holes allows water to enter and releases air. The fifth mechanical arm design includes only one joint that moves the mechanical arm in a left and right motion. The two-pronged claw at a ninety degree angle allows for the ROV to move up to the plastic ring tower and place the claw around one part of the ring without knocking the ring off of the ring stand. This design also has a two foot length which allows the mechanical arm to reach out at a distance and allows the mechanical arm to be functional and efficient.

 



The chart above rates five viable solutions for mechanical arm alternate solutions. The scale used for each category is on a scale from 1-5 where five is the highest and one is the lowest. Each solution was scored off of specification generated in the design process. Solution five fits the design the best due to the design’s rating in all specifications.