The Rationale Report

Rationale Report

For each of our four aquatic challenges we created four possible solutions. Each one of these solutions is a different design of an auxiliary unit attachable to the main hull which is capable of completing the given task. To decide which of the four alternate solutions is to be constructed and implemented we created a design matrix specifically for each unit. The criteria are simplicity, availability of materials, practicality, length of operation and accuracy of operation. Each alternative solution was assigned value from one to five for their performance in each criterion. The totals are given at the bottom of each spread sheet.

Simplicity deals with how many moving parts the solution has, and how many parts are involved. This can include motors and joint units. Availability of materials takes into account the scarcity of the the resources in the vex robotics kit, and how many of those resources this solution would use. This also deals with any materials not provided, and how difficult obtaining those would be. Practicality is the level of physcial possibility of the solution. In other words, its how easily the design would be to construct. The length of the operation is how long the unit takes to complete the challenge. The accuracy of the operation is the chance of success for the unit.

Challenge 1: Placing a Ping Pong Ball Through a Hoop

Criteria	Solution 1: Catapult	Solution 2: Slingshot	Solution 3: Pinball	Solution 4: Extending Claw
Simplicity	3	4	4	2
Availability of Materials	4	3	3	2
Practicality	2	3	2	4
Length of Operation	5	5	4	2
Accuracy of Operation	2	3	4	5
Total	16	18	17	15

Challenge 2: Towing a Stranded Vessel

Criteria	Solution 1: Hook	Solution 2: Magnets	Solution 3: Telescope Adhesive	Solution 4:Pincers
Simplicity	4	2	1	2
Availability of Materials	3	2	2	3
Practicality	4	3	2	3
Length of Operation	2	5	2	3
Accuracy of Operation	4	3	4	4
Total	17	15	11	15

Challenge 3: Sinking an Enemy Vessel

Criteria	Solution 1: Hook (downward)	Solution 2: Hole Puncher	Solution 3: Hook (upward)	Solution 4: Axe
Simplicity	5	3	4	5
Availability of Materials	3	2	5	1
Practicality	3	3	4	2
Length of Operation	2	5	2	5
Accuracy of Operation	4	4	4	3
Total	17	17	19	16

Challenge 4: Floating a Buoy

Criteria	Solution 1: Magnet Release	Solution 2: Rotating Claw	Solution 3: Slide	Solution 4: Tow and Cut
Simplicity	2	1	4	3
Availablity of Materials	1	3	4	1
Practicality	4	3	5	2
Length of Operation	4	2	3	3
Accuracy of Operation	5	2	5	3
Total	16	11	21	12

With these matrices the selection of each unit is significantly expedited. The design of the unit with the highest total score will be selected and committed to construction and integration.  For challenge one, solution one, the slingshot was selected with a score of 18. The hook was selected for challenge two with a score of 17, the upward rotating hook for challenge three with a score of 19, and the slide for challenge four with a score of 21. These four units will be more intricately designed and drawn out and finally put into construction. The hull will be based around accommodating these ancillaries.