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Housing Design Concepts

The overall shape of the robot was dependent on many different factors. These factors included how easily the housing could be assembled, the availability and cost of the components, how well the housing would be able to withstand the high pressure environment that the robot would be exposed to, how likely the robot would be to get stuck or lodged on a rock outcropping, as well as the overall durability of the housing as it would have to withstand multiple impacts with sides of the cave system over the course of a mission. Below is a list of the different initial concepts considered by team 6 along with the results of the decision matrix used to evaluate the expected performance of each.

Sphere- very uniform shape, splits in middle to install components
Egg- slightly oblong, it would be designed so that there would be enough drag on the narrow end to cause it to point in the direction of flow
Short Tube- comprised of PVC with end caps, it is as long as it is wide
Long Tube- comprised of PVC with end caps, variable length smaller diameter
Cone- oblong, drag on narrow end could cause it to point in the direction of flow
Cube- easily manufactured shape, low cost, unknown performance

Category	Ease of Assembly	Availability	Cost	Pressure Resistance	Likelihood to get stuck	Durability	Total
Weights	0.175	0.15	0.1	0.2	0.175	0.2	1
Sphere	5	4	4	10	7	8	6.7
Egg	3	3	3	6	8	8	5.475
Short Tube	10	10	10	9	7	8	8.875
Long Tube	9	10	9	8	5	7	7.85
Cone	5	3	3	6	8	5	5.225
Cube	7	7	7	4	4	8	6.075

Based on the results of the above decision matrix team 6 opted to use a short tube design where the length of the housing would be roughly equal to its diameter. This design was ultimately rejected after the team’s first full design. In order to accommodate all of the internal components necessary for the robot to complete its mission the housing would need to be constructed from a clear six inch diameter pipe. PVC pipe is not commonly available is this size and what is available is not of the correct color. The team replaced the short tube design with a 4” diameter long tube design that would be applied to multiple tubes to create a housing that had sufficient room and buoyancy. The design of the final housing will be discussed in more detail in the final design section.