Situation
For Lab 08- Performance Test 1: The group had to design and test two different AEV’s to find out which one would fulfill MCR the most and use energy the least. This test, which focuses on the design aspect, is crucial as it helps the team to improvise design features for the final AEV. The team could also recognize some additional features that would pop out during the test and integrate those ideas to the group’s final design. The final design from Lab 04 was chosen to be one of the two designs. The team used the concept and screening method and utilized the power analysis graph to be compared between the two designs. The group used the coding designed to be moved from the start until the first stop to reduce the period of AEV’s testing and increase work efficiency.
Results & Analysis
Based on previous run of AEV, the team decided to prioritize stability, power efficiency, energy efficiency and also coding consistency. The previous AEV design was not stable when moving in a straight line and also in turn. The team tried to make a few adjustments but a fair weight distribution was not achieved. The addition of the wings were not too helpful as the AEV was still shaking upon turning. Another major problem is the coding consistency. Due to complex feature of the AEV design, it can be said that the it leads to fast battery consumption thus producing inconsistency. The team reversed the rotation of the motor in order to stop the fast-moving AEV. However, the team realized that moving the AEV at high speed will make the AEV difficult to stop at the right time. Therefore, more calculation required to stop the AEV at the gate. Furthermore, it used high energy to stop the AEV from high speed Due to these circumstances, the team decided to change the way the team tackle the mission. Instead of moving the AEV at a high speed, the team decided that moving the AEV at a lower speed would be better to achieve coding consistency.
The team used the AEV sample design (on Carmen) as the reference and another two designs, Design A and Design B. Design A is the design used up to PDR Presentation and Design 2 would be the new design built by the team for Performance Test 1. The team decided to give a try on Design 2 which has a totally different concept from Design 1. The new design will focus on two concepts which are power efficiency and stability. The new concept used almost the same coding as the previous concept. The only things that differ are the value in the parentheses, which were because the new design moved slower than Design 1, thus requiring less effort to stop the AEV at the gate. The similarity of the coding can be seen through Figure 1. In the new design, the team decided to use only one motor with Pusher EP-3030 configuration instead of using two motor. This was done to avoid the AEV from shaking as much as Design 1 when stopping. The team believed the Design 1 shake a lot because the force used to stop the fast-moving AEV was high. That was why the team decided to run the AEV in a slower mode by using just one motor. Even though the new design has no wings on any side of the AEV, based on observation, the AEV was more balance when moving in a straight line and turning; nevertheless, this come at the cost of reduced velocity because the AEV only used one motor. The time taken for Design 2 to reach the gate was 10 seconds longer than Design 1. The team decided to improve the second concept, power efficiency, because the team would like to minimize as much energy as possible. Based on data collected using the AEV Analysis Tool, the second objective was a success as the total power used to reach the first gate for Design 2 saved about 20 Watts of power compared to the Design 1. This data was based on the same coding up to the first gate.
The team ran concept screening and scoring scoresheet to make a critical comparison of the two designs with the reference design. The aspects that the team look at are stability, weight, cost, balanced in turns, center of gravity, maintenance and time required to complete mission. The stability was compared when the AEV placed on the railway. The weight, maintenance, and cost of each designs were compared based on the number of components used for each AEV. The balanced in turns and center of gravity were compared based on the behavior of the AEV when it is moving along the railway. The time required to complete mission was compared by measuring the time taken to reach the first gate. Based on both scoresheets, Design 2 should be developed further and be used for the completion of the mission in this project.
Table 1 : Concept Screening Scoresheet
Table 2 : Concept Scoring Scoresheet
Table 3 : Power used for each design