Data Analysis Update #2

Data Analysis Update #2

During the Advanced Research and Development period, the team was focused on finding the most effective ways to brake and how to implement the servo motor as a braking mechanism. Three distinct methods were identified and two trials of each method were completed. The results can be seen below:

Coasting – Power vs. Distance Figure

The first braking method tested was the coasting method. Similar to letting off the gas while driving a car, the motors were turned off after being on for a specific duration. The benefits of this method come in the form of energy conservation and a gradual decrease in speed leading to a comfortable stop for cargo and passengers. The cons of this method is the distance required to come to a stop, the time it takes to stop, and the accuracy of the method. The average stopping distance once the motors were switched off was 1.7 meters. The average energy consumed per run was 9.5 J/m.

Reverse Motors – Power vs. Distance Figure

The second braking method tested was the Reverse Motors (Power Braking) method. Similar to throwing your car into reverse and hitting the gas to stop the car, the motors reversed directions and ran for a specified duration until the AEV came to a halt. The benefit of this method include shorter stopping distances, but the drawbacks are power consumption and the potential to traverse in the opposite direction intended if the stop is miscalculated. The average stopping distance once the motors were reversed (seen in the graph at the beginning of the large peak) was 1.3 meters. The average energy consumed per run was 10.9 J/m.

Servo Motor – Power vs. Distance Figure

The final braking method tested included the user of the servo motor. The servo motor was fitted with a wooden arm and rubber brake that can be adjusted to press against the rail in order to stop the AEV. Similar to applying a brake directly to the ground while in a car, the servo motor applied the brake directly to the rail to stop the AEV. The benefit of this method includes extremely short stopping distances and minimal power consumption from braking. The cons include the potential wear and tear on the brake, the additional cost of the servo motor, poor power efficiency, and the hazards that exist from improper application of the servo (such as jumping the AEV off the track). The average stopping distance once the servo was applied to the rail was 0.2 meters, and the average energy consumed was 16.2 J/m.

When it comes to braking, the servo motor is king. The servo motor stopped 850% faster than coasting and 650% faster than reversing the motors. This does come at a price by significantly complicating the braking process, increasing the cost of the AEV, and adding potentially hazardous conditions. The servo motor is also 170% more energy demanding than coasting and 150% more energy demanding than reversing the motors. Although the servo introduces new issues, the potential upside of fast and efficient braking is something that can’t be ignored. Moving forward, the team will need to develop regulations to safely operate the AEV while utilizing the servo motor.

 

Data Analysis: Update 1

Data Analysis: Update 3