Wednesday, October 17, 2007

Frame Selection/ Rejection

FRAME:
Alternate solution number one is a relatively simple design. The supporting structure is made out of two inch PVC. It is a rectangle of about one and a half feet wide and two to three feet long. The final dimensions will be chosen according to the size of the arm. Its base to hold all of the components such as the bilge pumps will be mounted on a hard plastic mesh. An arm will be mounted to the front of the PVC structure. A camera as seen in the alternate solution will be mounted on the front. The arm when completed will be mounted here also. If this solution is further developed; one or more cameras will be added to provide better sight of the surrounding environment while the craft is maneuvering. This solution is the most maneuverable of the three solutions because it is two dimensional in the sense that it is flat and everything will be mounted in the same plane. Where as the third alternate solution has three dimensions and is more bulky so it would maneuver more slowly through the water. The simplicity of this design makes it one of the more logical solutions. However, the design being flat and two dimensional will make the buoyancy absolutely crucial. The crafts buoyancy will have to be perfectly tailored so that it does not tilt or lean to one side inhibiting its maneuverability. This craft also has a relatively small area compared to the second solution for mounting the components. The bilge pumps for this solution would have to be carefully laid out so that the craft is balanced and not overly weighted to any side as this may cause maneuverability problems. However, if this is done properly this craft is one of the more sensible solutions to build for these reasons.

Alternate solution number two is another two dimensional frame. However, it is more complicated than alternate solution number one. It is an octagonal frame, having eight sides and eight forty five degree joints. It is made of PVC as well as the first alternate solution. The base will be made with a hard plastic mesh. Having eight sides it requires that every cut be precise to more than an eighth of an inch, if there is more than one cut that is off the craft will be lopsided and the balancing of the craft while it is in the water will be much more difficult. The dimensions of this solution will once again be chosen according to the size of the mechanical arm if this solution is chose. If chose however, the frame will measure no more than three feet across at any point. This solution being two dimensional needs to be balanced properly so that the buoyancy will perfect, and the craft will neither sink nor float drastically to the surface. This solution is good for holding components on it. Equipment will be easier to mount on because it has a larger surface area to do this. This solution is not the most sensible solution of the three alternate solutions; the cons outweigh the pros of this solution.

The third alternate solution is a three dimensional frame. This is the most complicated frame solution. It has a base made of plastic mesh like the first two solutions. This would hold all of the bilge pumps and other components. ­­This craft would be the easiest to balance if chosen because it is has three dimensions. Neutral buoyancy would be easier to achieve with this craft design. The bags used for the buoyancy would be attached on the top of the craft, keeping the top upward stopping any possibility for rolling the craft. This solution would easily fit a mechanical arm on the front and have many points for mounting the components. However for the MATE competition something this bulky would be excessive making its maneuverability. The craft should be slick and move quickly through the water which this solution would not do this as well as the first or second solutions. This solution would be more viable for use in a scientific field because it would keep all of the components mounted to it protected. In a swimming pool; a craft will not be in potentially damaging solutions to the craft. In the ocean or an outside body of water an ROV would be exposed to much more volatile conditions that could harm the bilge pumps and components. This solution is not the most sensible solution.

The first solution will be the craft that is further developed and designed. It is the most sensible design for the purposes of the ROV MATE competition. It has a low profile so it will move through the water easily. The mechanical arm will be easily mounted on the front, as well as the bilge pumps and the other components on the hard plastic mesh base. The model will be made at half scale for the end of first marking period presentation.
This is the final developed solution created in architectural desktop.

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