Design Process Lab 11
Performance Test 04: Final Testing
For Week 11- Performance Test 4 (PT4): The group had to have the AEV to complete a full run on track while fulfilling the Mission Concept Review (MCR) requirements before the AEV get evaluated by the instructional team. The results from PT4 would be filed into the Critical Design Review (CDR). It is important to do this final test and make some adjustment on the AEV as this lab reflects how successful the group’s AEV project is. The team members made some adjustment on coding to have the AEV fulfill the MCR and while having less power used. The team also reviewed the guidelines for AEV Final Test Evaluation and the MCR while testing the AEV on track for the last time, to guide the group to pass the test well.
Results & Analysis
For this lab, the team had accomplished the mission of MCR which is to run the AEV along the track and take the R2D2 within 2.5 minutes. The power used for this lab is 256 watts which is reasonable. However, the team found out that the AEV is experiencing inconsistency every time it was tested on the track. After several runs, the team come up with two hypotheses of the AEV’s inconsistency on the track such as the number of mark used for the coding is not equivalent to the calculation that has been made based on the length of the track and the power of battery that affects the coding to run on the AEV. The main problem with the AEV is it does not consistently stop between the two sensors, thus blocking the gate and the rest coding of the AEV. So, the team decided to have a discussion with the instructor and the teaching assistants to find the solution for the problems. The team found out that the second hypothesis is true, which means that the battery power is affecting the coding of the AEV. The battery power needs to be larger from a certain value so that the coding will run smoothly. After several times testing the AEV, the team will check for the battery voltage so that it beyond the minimum requirement of the standard battery. Next, the team found out that there are many scratches on the reflective tape on the wheel of the AEV. The scratches are affecting the sensor to count the marks travelled by the AEV, thus resulting on the coding of the AEV. The team get a suggestion from the teaching assistant to change the tape and later, the AEV run smoothly and complete the MCR. The team also have made some improvements on the AEV such as using the 40% of motor speed instead of 30% because the team realized that the AEV is running very slow when using 30% of power and it will affect the inertia of the AEV. The team wants to have an optimum value of inertia to stop the AEV in the range of the sensors. The team still wants to proceed with the design that only uses one motor because it will reduce the amount of power used for the AEV. The team also did not use the mini-servo motor because it will produce spike in the energy level of the AEV, thus increase the amount of energy used. However, the team also have the aim that is not resolved for the AEV testing which is to complete the MCR below than the 200 watts of power. The minimum value that the team have reached was 220 watts and for this lab, there is an increment of 36 watts which comes from the level of motor speed which is higher than before. Based on the team final evaluations, the team believe that the AEV made successfully complies two of three mission objectives: energy management and operational efficiency. The data recorded based on the AEV Analysis Tool suggests that the whole run requires an amount of 268 Watts. This is a reasonable measure based on the data recorded from the other teams in the class. The AEV made is also cost effective compared to the previous designs. The number of parts used in the final design are also much lesser than the previous designs which makes it easier for the team to modify in case of any new idea or if the AEV requires some fix. These reasons suggest that the final AEV fulfil the energy management and operational efficiency goal. The team faced a difficulty in achieving the third objective, operational consistency. This is because due to the battery. The change in battery voltage causes the inconsistency for the AEV. This was the issue with the previous design. The team decided to make a new design that only use one motor before because of this issue. However, the use of one motor still does not resolve the issue despite numerous changes made on the mark counting in the coding. The team discuss and agree to specific characteristics of an ideal AEV that will complete the MCR while having the most efficient and cost effective. The characteristics are AEV should be using one motor, the power use should not be more than 40% power setting, the AEV must have a great balance, the AEV must has a light weight in order to reduce the energy required to move and also to reduce inertia, and lastly, the team agrees that a brake mechanism builded around servo motor should be constructed to help stop the AEV. This is because this type of braking system prevents the AEV from coasting and will surely improve consistency despite of the drop of battery voltage. In order to build the ideal AEV mentioned above, the team will need to program a new coding and also need numerous trials to test the effectiveness of the system. Using the AEV Analysis Tool and also by taking the time required for the AEV to complete the MCR, the team believe that the AEV proposed above will be the one that matches all the mission objectives successfully.