Results and Improvements

Design

Sam’s lightweight and air resistant model was chosen as an upgrade to the initial design.

Problems Solved

Team L’s AEV went through a multitude of changes before reaching its optimized final state. These changes were the result of countless hours of research, testing and analyzing results. 4 main problems contributed to affecting the driving and braking accuracy:

Driving Error:

The AEV ran by tracking the distance which it moved with an IR sensor. Often times marks would miss and the AEV would fall too far or too short. Throughout all of the performance tests, the adjusted travel for marks was set to 12 ft. and 6 inches instead of the 13 ft. to accommodate for the skipping of marks. This number was determined by the accumulation of various trial and error.

Braking Error:

Another weak side of propeller driven vehicle was that even if the reflectance sensors were perfect, there was still a huge inconsistent error when breaking. When using the reverse-propeller braking, the AEV coasted for about 2 ft. at 35% power which differed depending on the battery and speed. To minimize this, Team L implemented testing using the servo motor to brake.

Servo Attachment: 

One of the biggest problems was securing the servo. When it was loose, it would brake with inconsistent errors. The design was changed to use duct tape, which miraculously created whole new consistency issues. On the final test it was discovered that duct tape was also rubbing against the wheel. A rubber band on the servo arm also aided in gripping the wheels.

Efficiency

Power efficiency was an important area to optimize. In order to do this, data was gathered on Push vs. Pull systems and servo vs. propeller systems.

 

 

Before deciding on using the servo, Team L compared its power consumption with against the propeller-braking to find that it did not use up any more power. The servo system only used on average 8 watts while the reverse-propeller used 9 watts.

 

It was discovered that Pull model used 50% more power at an average of 6 watts than the push at 4 watts average. Team L decided it would be better to use push after connecting to the cargo instead of pull.