The mission of the Advanced Energy Vehicle project is to connect the people living in the urban desert of Linden to the economic opportunities in Polaris using an autonomous, electric powered vehicle moving along a monorail system. The vehicle must first be able to move forward steadily from behind the starting line as it proceeds up a 2.39 degree incline and then stop between two designated sensors for 7 seconds before proceeding through the gate. After proceeding through the gate the vehicle will then proceed down a 1.19 degree incline where it will connect to the payload using a magnetic hitch and pause for 5 seconds. Then the AEV will proceed back up the 1.19 degree incline and stop between two sensors before the gate for 7 seconds again. Afterwards, the AEV will proceed down the 2.39 degree incline past the starting line and stop in the starting dock while ensuring the payload is not disconnected during elevation changes.
In order to do this the team has chosen to make use of a belt-driven propulsion system instead of a propeller-driven system due to its superiority in stability, braking, and energy efficiency. The team decided to do this after observing the inefficiency of a propeller driven system in lab. The propellers excelled in moving the AEV forward but used too much energy in braking and were inefficient when moving in the reverse direction. The initial idea was to use a system of gears to transfer power from the high-rev, low – torque motors in order to turn the wheels on the monorail. This idea was later modified to a belt – driven system bc it would require less maintenance, and be more reliable than involving several 3-D printed gears which would grind together and suffer a faster rate of degradation than a belt turning on several pulleys. After creating an initial design the team performed battery testing using the sample AEV design and discovered that energy output from the battery remains constant as battery voltage decreases, ensuring reliable battery performance throughout future tests.
After receiving the parts necessary for a belt-driven system the team went through a long and tedious process of refining the AEV design so that the AEV could move with stability and efficiency. The team initially faced the problem of the AEV not moving at all, or wobbling because it was moving too fast. The team’s first major discovery was that the 3D printed motor pulleys fit improperly and the motors were slipping inside of the pulleys failing to move the belt. Therefore the team was forced to break two provided propellers to make a modification to these pulleys. Additionally, the team tried adding a third motor but eventually discovered that a third motor made no significant improvements to AEV performance and so returned to a two-motor design. After this it was found that the belt shape was an inefficient configuration because it did not have a high enough area of contact between the belt and the pulleys and it also created too much tension in the system preventing the pulleys from moving if the belt was pulled too tightly. After changing the belt configuration the team noticed a significant decrease in power usage, more stable AEV movement, and a more reliable AEV performance for the same code. This final design refinement brought the team to its completed AEV design which performed efficiently, reliably, and safely.