After Performance Test 1, the team realized that the method that was used for breaking, the brake() command, was not efficient enough. The AEV coasted to a stop, which made the location where it came to a stop unpredictable and unreliable due to the variance. In Performance Test 2, the team decided to incorporate reverse() commands to spin the propellers the opposite way, therefore contributing to the AEV coming to a quicker, more precise stop. This was not a requirement for Performance Test 2, but it was implemented to allow future runs to be more successful. For Performance Test 2, the task was to first complete the tasks of Performance Test 1, which was to approach the gate in the range which would activate the sensors, wait for 7 seconds for the gate to open, then proceed through the gate. The tasks added to Performance Test 2 were after the gate, to run the AEV to the loading dock and attach to the caboose using a magnet. The AEV and the caboose stop in place for 5 seconds, and then move out of the loading dock while still connected [1]. Team A was able to complete Performance Test 2.
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// Reverse all motors, pushes forward
reverse(4);
// Accelerate from 0 to 40% power in 1 second
celerate(4, 0, 40, 1);
// Motors at 40% power until 8 ft mark (160 on full battery, 165 for used battery), midpoint of incline
motorSpeed(4,40);
goToAbsolutePosition(160);
// Brake to cut power
brake(4);
// Reverse all motors, accelerate form 0% power to 40%, in 1/4th second for 2 seconds, to stop
reverse(4);
celerate(4, 0, 45, .25);
goFor(.9);
// Break to stop push-back-break before the gate
brake(4);
// Pause for 8 seconds
delay(8000);
// Reverse to move forward through gate
reverse(4);
// Motor speed 35% until 22 foot mark
motorSpeed(4, 35);
goToAbsolutePosition(405);
// Brake to cut power
brake(4);
// Reverse all motors, accelerate form 0% power to 20%, in 1/4th of a second, to stop before securing load
reverse(4);
celerate(4, 0, 40, .25);
goFor(.8);
// Break
brake(4);
// Pause for 5 seconds to secure load
delay(6000);
// Increase motor speed 0% to 35% for 1 second
celerate(4, 0, 40, 1);
//move back towards gate
goToRelativePosition(-100);
// Break before gate again
brake(4);
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During the Performance Tests, the team noticed that they were unsure of the best way to adjust the braking mechanism. Due to this, Advanced R&D 3 focused on braking mechanisms. As shown in the video linked below, at first the team struggled with breaking the AEV the correct way so that it wouldn’t slam into the caboose.