We decided to perform a test of two different styles of braking, coasting and power braking, because braking is a very important part of transportation. When citizens are relying on a form of public transportation, they expect a high level of safety while also balancing the performance of the vehicle. The coasting braking system is where the team coded the AEV to gain speed then cut the energy to the motors and let the AEV roll to a stop. The power braking system is where the motors are reversed when the team wants to initiate the braking system. This allows the opposite propulsion force to slow down the AEV. There are many different aspects of braking that we looked at. The first was power consumption and how much energy was actually used with each style of braking. We also analyzed the actual stopping distance and consistency of each braking system. These two variables were very important to us because when we were tasked to design this vehicle, our top priorities were to create a safe and energy vehicle.
We ran 10 trials for each type of braking. One braking method involved using the motors to reverse to allow for a quick stop and the other method allowed the AEV to come to a complete stop by coasting. It was observed that even though the vehicle came to a stop much quicker with the assistance of the motors, the whole goal of this project was to make an Advanced Energy Vehicle.
However, while we want the vehicle to be as energy efficient as possible, we also want to provide the highest level of safety possible. With how our smart city is designed, the AEV will need to be able to make many stops and be able to pick up and transport a passenger car. With the possibility of a high impact collision, because the AEV is coasting without any other form of stopping power, we feel that both methods of breaking are needed. Coasting to a stop is only possible if the AEV track is free of any stops or even inclines/declines. The added momentum from the hills on the track will make the AEV gain more speed than intended. This is why sometimes the assisted power breaking will be needed. It will prevent the AEV from not being able to come to a stop at higher speeds.
We also are researching into using a servo brake to stop our AEV, as we believe that the servo can provide a more energy efficient braking system, and also provide a shorter stopping distance. Using either of these in combination with coasting will provide the desired results for our AEV, as we will have the abilities at our disposal to handle any situation the vehicle is put into.
Code Used:
Refer here for information on command functions.
| Coasting Code | |
| Code | Explanation |
| reverse(4); | reverses both motors |
| celerate(4,0,25,5); | accelerates both motors from 0% to 25% |
| motorSpeed(4,25); | initialize speed at 25% |
| goToAbsolutePosition(-200); | initialize distance to travel |
| brake(4); | cuts both motors |
| Power Braking Code | |
| Code | Explanation |
| reverse(4); | reverses both motors |
| celerate(4,0,25,5); | accelerates both motors from 0% to 25% |
| motorSpeed(4,25); | initialize speed at 25% |
| goToAbsolutePosition(-200); | initialize distance to travel |
| reverse(4); | reverses both motors |
| motorSpeed(4,25); | initialize motors |
| goFor(5); | initializes time |