The team used a common brainstorming technique called Attribute Listing to begin the design process of the AEV. In this method, different components or ideas are brought together to form a whole. (College of Engineering, 2019) The process ends with a set of tables that will decide the most appealing designs by putting weights to different success criteria. These tables are thought of as decision matrices.
Concept Screening
“A concept Screening Matrix is a quick method to eliminate ideas.” (College of Engineering, 2019) The idea is to compare different parts of designs to criteria. In order to do this, the team decided that there were six important criteria. The individual concept sketches (3) and the team concept design (1) are compared to the reference AEV. The four new concept designs are graded against the reference AEV by simple symbols where,
- + : the concept is better
- – : the concept is lacking
- 0 : the concept and reference are equal
Concept Scoring
Concept Scoring is used to, “Provide better definition of concepts and help define the final project”. (College of Engineering, 2019) The matrix uses the same set of criteria. However, the criteria in this matrix is also weighted. This means that each criterion will be accompanied by a number that is decided by how important that criterion is. The sum of the numbers over the various criteria must add to be 100. Each concept sketch is rated and compared as in the Concept Screening Matrix. The rating is graded from 1 – 5. The grade for that criterion is multiplied by the weight. The product will give the weighted score. The weighted scores across all criteria is added together for a “Total Score”. The concepts with the highest “Total Score” will be developed.
Final Design
The final design was centered around two main concepts. The team wanted the AEV to proportion the weight evenly across the vehicle, including centering the weight, and design with symmetry in mind. These two concepts are part of a bigger bucket which is to make the AEV as efficient as possible. In order to design the vehicle efficiently, the weight needs to be distributed evenly because the vehicle travels theoretically equal distances forwards and backwards. When the weight is distributed evenly, drag and friction are reduced and equal in both directions. In the current design, the trolleys can connect to either end of the vehicle.
Centering the weight evolved over the design process. Initially the team was going to place the components on the same plane and use the weights to balance the center line as a fulcrum by adjusting the position relative to the center line. The final decision was to center the components over the center line on different planes. The Arduino is placed vertically on the hanging bracket to the right; the Battery is placed under the cross frame similar to the reference AEV. This design will ultimately save on space and material. The motors are placed under the cross frame, or wings, similar to an airplane. The team also decided on large blades to generate the most power.
