Lab 8- Performance Test 1

Results

The two prototype designs that were tested during Performance Test 1 were both based on the same base model. The model was an evolution on a design created in Lab 4 with improvements to both the weight and the balance. In both of the designs the T-arm was used to attach the wheels to the body of the AEV. A medium sized rectangular piece was then attached to the arm so that its large sides were parallel to the flat part of the arm. A modified version of the T block was then attached perpendicular to the rectangle. The motors were attached to the bottom side of both sides of the top of the T block. The arduino also bolted to the side of the rectangular piece. The difference in the two designs comes from the location of the battery. In the first design, the battery was placed in between the holder plate and the modified T block on the bottom of the AEV on the side opposite of the Arduino. In the other design, the battery was bolted to the rectangular piece on the opposite side of the Arduino.

While the two designs can be compared theoretically, the real, tangible differences could be clearly seen when the two designs were run on the track. Both designs the group was considering were tested on the track using the same code as a control. The code tested as a control was what the group developed for accomplishing the first part of the objective, from the starting point to the gate. One noticeable difference was that the second design, with the battery placed on the same piece as the arduino, coasted further than the first design. As seen in Figure 3, below, the second design was able to reach the number of marks in a lesser time. This decrease in time results in two important results. The first is that the AEV was able to travel an identical distance in a lesser time, meaning that the acceleration was greater than the other model. This leads to the inference that the net force on the AEV must be greater and that the frictional force must be lesser than the other model. The second result is that the energy consumed by the second design is less than that of the first because the area under the curve in Figure 3 is lesser. However, the difference between the two is not very significant but it still is an improvement. This slight difference in energy was expected by the group because of the only significant factor changed was the center of mass of the AEV.

Figure 3: AEV Power vs Time

Reiterating what is displayed in the graph in a quantitative way, Table 3, below, shows the breakdown of energy consumed by the AEV by each phase of the test run’s code. Phase 1 is the first plateau shape shown in Figure 4. It is where the largest portion of energy was consumed also where the AEV traveled the furthest. Here, the first design consumed over one more joule of energy than the second design. In Phase 2, the AEV’s motor was not running and the vehicle was just coasting, which is why the energy consumption is so low. In this phase, model one actually consumed less energy than the second model. The motors were reversed for Phase 3 and powered as to stop the AEV before the gate. This phase consumed the second most amount of energy with the difference between the designs being miniscule. Lastly, as the AEV stopped in front of the gate, the motors were off and the energy consumption was 0 for both designs. Overall, the total energy consumed by the first design was only about 0.8 more than that of the second design.

Table 3: AEV Energy Phase Breakdown


This information is perhaps the most useful to the group in future testing runs because the different methods of programming the AEV can be compared by their energy consumption. This information is also useful because the shapes of each command’s energy curve can be seen and the most efficient commands can be used. From there, the most efficient commands can be blended together with the most reliable and consistent commands in order to achieve the best code sequence to accomplish the AEV’s mission.