The purpose of this lab was finding the appropriate position for AEV to touch the Cargo. Nonetheless, the team found the code and strategies in order to make the AEV successfully take back the Cargo back to the Gate. There were two strategies used in the lab, one was that use the same power input, the other was use higher power to start the AEV, and use lower power to maintain the speed. Moreover, the team also planned to make few modifications to the hardware to reinforce the servo motor to avoid unnecessary movement to cause failure, and use tape stop the wires from being in the way of or stuck the wheels.
Plot 1. Times vs. Power
Plot 2. Distance vs. Power
The plots of time vs. power and distance vs. power are provided above. Each of the two plots is divided into 4 parts. The first part is from the starting point to gate system. The second part is from the gate system to cargo area. The third part is from cargo area to gate system on its way back. And the fourth part is for the AEV running back from gate system to starting point. In this test, team successfully made the AEV complete the whole mission. The total time used was 59.04 s. The total distance traveled was 24.9507 m and the total energy used was 287.18 watts, which was the least energy used in PT3. On the first two parts, when the AEV ran to the cargo area, team set the speed to be 25% using the command of “motorSpeed(4,25*powerAdjust())”, which according to test, can make the power output stable. When the AEV came back to the starting position, team changed its idea. On its way back, team came up with an idea that the speed can be first set up to 50% to make the AEV and cargo movable. After going for some distance, speed can be adjusted to a smaller number in order to keep the AEV running as well as saving energy. That is, the commands of “motorSpeed(4,50*powerAdjust())” and “goToRelativePosition(-100)” were called to make the AEV run for 100 marks backwards, with the speed being 50%. After that, the command of “motorSpeed(4,35*powerAdjust())” was called, which slowed down the AEV and made it keep moving for the rest part of the part.
In the whole process of the AEV’s running, team observed that in part 1, which is from the starting position to gate system, the distance traveled by the AEV changed frequently. When used the same parameter of distance, usually “goToAbsolutePosition(440)”, the AEV can stop exactly between two sensors. But sometimes it could crash the gate and sometimes the vehicle cannot get to the first sensor. Even now, team still cannot fix such problem efficiently.
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Preliminary Design Review(PDR)
Appendix