Methodologies

Advanced Research and Development 1&2

Reflectance Sensors

Equipment

• Constructed AEV(*with tested, functional reflectance sensors)
• LI-PO Battery
• Test Track

Controlled Variables

• The placement of reflective tape on wheel
• The body and motor assembly
• Distance as a reference

Test 1

The first component of testing will be the planarity of the sensors and how it affects the recorded data and coding. The team has noticed that the sensors frequently are angled in the same plane as the arm and that they are also at an angle to the plane of the arm as well.

1. Does the planar rotation affect the sensors?
2. Does the planar skew affect the sensors?

The team will test these two questions by recording data for the sensors as they are vs the actual distance to check for accuracy. After, the team will rotationally align the sensors and complete the same test. The results will determine whether the team should make a plate or cover to hold the sensors in a more optimal position. The distance testing will be done as one of the team members hold the cart and manually roll it a known distance. While it rolls, the reflectance data will be recorded. The team will calculate the distance that should have been travelled based on the data collected from the reflectance test and compare it to the actual distance.

Procedure-

1. The tabletop track was set up and the distance between one wheel at the right most end of the track and the same wheel at the left most end of the track was measured in order to know how far the AEV would actually be moving in one trial.
2. The reflectance sensor test program was opened on one of the desk top computers and the window that counts the number of marks the AEV travels was opened in order to record accurate data. For each trial, the program was restarted in order to restart the count of marks.
3. Six trials were run with no alterations to the sensors and how they are attached to the arm (Figure 1). The runs were performed with using the tabletop track so it was easier to control how far the AEV actually moved. The back of the AEV was started flush against the one wooden beam (Figure 2) and was manually moved until the front edge of the AEV was flush against the wooden beam on the other side of the track (Figure 3).
4. The sensors were taped flush to the arm of the AEV and perpendicular to the base of the AEV (Figure 4).
5. Six trials were run with the new alignment of the sensors to the AEV’s arm. The runs were conducted in the same exact way as before and data was collected in the same exact way as well.

Figure 1. No alterations to the sensors

Figure 2. Starting position of the AEV on the table top track

Figure 3. Ending position of the AEV on the table top track

Figure 4. Alterations to the sensors

Data-

Actual Distance the AEV Travels on the Stationary Track- 7 ⅞ inches

*Measured from center of the outermost wheel*

Each Mark= 0.4875 inches

Note- The team decided to remove the motor so the AEV did not have to be twisted when it was pulled on the track.

Data Analysis-

*Number of marks used for calculations in this table and then translated to distance in the next table*

Conclusion of Data- The plane of the sensors on the arm of the AEV do not help the accuracy of the reflectance sensors. It might actually cause negative effects when the sensors are taped down flush to the arm of the AEV so it is advised not to tape them down.

Implementation- It is advised that the sensors should not be taped down to the arm of the AEV; where they naturally sit on the arm is more accurate than taping down the sensors.

Original Test Questions and Answers-

1. Does the planar rotation affect the sensors?

Yes the planar rotation affect the sensors but when the sensors are rotated to be perpendicular to the base of the AEV, the accuracy of the reflectance sensors decreased.

1. Does the planar skew affect the sensors?
   1. Yes the planar skew affect the sensors but when the sensors were taped flush to the AEV’s arm in an attempt to correct the planar skew, the accuracy of the reflectance sensors decreased.

Note- The team did not test with the nose cone as the other groups in our team were not testing with the nose cone so the team did not want our data to be skewed by the nose cone.

Test 2

In the second phase of testing, the team will observe the effects of starting the run of the cart in the middle of the two metallic tape pieces and ending in the middle of tape pieces.

1. Is there a most accurate way to have the wheels oriented in order to achieve precision of distance travelled on the track?

The team will test this by measuring many short trial runs of the start and finish with varying wheel orientations. Data will be collected and compared to the actual length the AEV traveled.

Procedure-

1. The tabletop track was set up and the distance between one wheel at the right most end of the track and the same wheel at the left most end of the track was measured in order to know how far the AEV would actually be moving in one trial (same procedure in the other reflectance sensor test).
2. The reflectance sensor test program was opened on one of the desk top computers and the window that counts the number of marks the AEV travels was opened in order to record accurate data. For each trial, the program was restarted in order to restart the count of marks (same procedure in the other reflectance sensor test).
3. Five trials were run with the reflection part of the reflectance sensor completely shown on the top of the AEV wheel (Figure 5). The runs were performed with using the tabletop track so it was easier to control how far the AEV actually moved. The back of the AEV was started flush against the one wooden beam and was manually moved until the front edge of the AEV was flush against the wooden beam on the other side of the track; exactly as the tests were run in the other reflectance sensor test.
4. Five trials were run with the reflection part of the reflectance sensor only shown on the left half, the back half, of the AEV wheel (Figure 6). The runs were conducted in the same exact way as before and data was collected in the same exact way as well.
5. Five trials were run with the reflection part of the reflectance sensor only shown on the right half, the front half, of the AEV wheel (Figure 7). The runs were conducted in the same exact way as before and data was collected in the same exact way as well.
6. Five trials were run with the reflection part of the reflectance sensor not shown at all on AEV wheel (Figure 8). The runs were conducted in the same exact way as before and data was collected in the same exact way as well.

Figure 5. All reflective tape showing on top of the wheel

Figure 6. Reflective tape shown on the left (back) half of the wheel

Figure 7. Reflective tape shown on the right (front) half of the wheel

Figure 8. No reflective tape shown on the wheel

Data-

Actual Distance the AEV Travels on the Stationary Track- 7 ⅞ inches

*Measured from center of the outermost wheel*

Each Mark= 0.4875 inches

Data Analysis-

*Number of marks used for calculations in this table and then translated to distance in the next table*

Conclusion of Data- The most accurate reading of the reflectance sensor is when the reflective portion of the sensor is shown on the left half of the wheel. The least accurate reading of the reflectance sensor is when the full reflective portion of the sensor is shown on top of the wheel.

Implementation- It is advised that when testing and performing tasks with the AEV on the track, the reflective portion of the reflectance sensors should be shown on the left half of the wheel only in order to get the most accurate reading for distance.

Original Test Questions and Answers-

1. Is there a most accurate way to have the wheels oriented in order to achieve precision of distance travelled on the track?
   1. The most accurate way for the reflectance sensors on the wheels to be orientated with the left (back) half of the wheel covered in the reflective portion of the sensors.

Propellers

Equipment

• Constructed AEV + LI-PO Battery
• Designated Track(s) (308 and/or 224)
• Different propellers (as necessary)

Controlled Variables

• The body assembly of the AEV
• The reflectance sensors of the AEV
• The battery capacity and performance of the battery

Test

The component of propellor testing that will be examined will be the size of propellers on the motor. Our main questions are as followed:

1. Does the size of the propellers affect the distance traveled by the AEV?
2. Does the size of the propellers affect the time the AEV moves on the track?
3. Does the size of the propellers affect how much power needs to be used to travel a certain amount of distance?

The team will test these two questions by first using the original two propellers (small rectangular propellers) on each motor. The reflectance sensor tests will be used to record speed of the AEV and the energy used by the AEV over time. The test will be conducted with a simple forward movement of the AEV on the track. The same sensor tests will be used to determine if the using the larger, curved propellers affect the speed or energy efficiency of the AEV. Our goal is to have a total of ten tests conducted. Five for the smaller propellers and five for the larger propellers so an average of the data can be calculated.

Procedure-

1. The following code will be used to test the propellers on the AEV.

motorSpeed(4, 35);

goFor(4);

brake(4);

1. First, the standard propellers will be used which are considered to be the smaller propellers shown on the top half of figure 9. The AEV will be run using the code on the test track. For each run, the time of the run will be recorded immediately when the propellers start to move and then when the AEV itself stops moving. After the run, the AEV will carefully be lifted off the track and the number of marks traveled will be recorded. This will be done five times and after each time the AEV must be reset so data can be collected again.
2. Next, the larger propellers, shown on the bottom half of figure 9, will be put on the AEV and tested in the same way as described above but with the following code*. Five runs will be recorded.

motorSpeed(4, 20);

goFor(4);

brake(4);

*the code had to be changed to 20% power for the larger propellers because at 35% power, the AEV moved so far that it would have gone off the track

Figure 9. Different sizes of the propellers

Data-

*see note above in procedure for why the % power was changed between the two types of propellers

Data Analysis-

Conclusion of Data- The larger propellers traveled farther and required less energy to travel farther than the smaller propellers.

Implementation- The larger propellers should be used on the AEV to increase energy efficiency of the AEV and distance traveled.

Original Test Questions and Answers-

1. Does the size of the propellers affect the distance traveled by the AEV?

The larger propellers made the AEV travel a farther distance than the smaller propellers made the AEV travel despite the Arduino running at a lower power percentage with the larger propellers. Additionally, the average distance in inches per percentage of power is larger for the larger propellers.

1. Does the size of the propellers affect the time the AEV moves on the track?

The smaller propellers ran for a shorter amount of time than the larger propellers ran for because the smaller propellers made the AEV travel a smaller distance. Additionally, the average time in seconds per percentage of power is smaller for the smaller propellers.

1. Does the size of the propellers affect how much power needs to be used to travel a certain amount of distance?

The larger propellers were tested with 20% energy. The smaller propellers were tested with 35% energy. The larger propellers traveled 3.32in and traveled for 0.377s per percentage of power. The smaller propellers traveled in 0.889in and traveled for 0.201s per percentage of power.

Advanced Research and Development 3

Power Braking versus Coasting Constraints in Code

Equipment

• Constructed AEV(*with tested, functional reflectance sensors)
• LI-PO Battery
• Track with Gates and Slopes
• Data Extraction Tool

Controlled Variables

• The body and motor assembly
• Power Percentages will remain the same in each code

Test

The team would like to know more information about running the code in terms of using power braking versus using mostly coasting to brake and then a small amount of power braking. The team will mainly test these two factors in relation to energy consumption. Additionally the team would like to test the accuracy and consistency of the two different types of braking.

1. For our current code for performance test 1 which uses power braking, what is the energy consumption?
2. If the code for performance test 1 is modified to stop the motors to coast to stop then use a small amount of power braking, what is the energy consumption?
3. For the two different scenarios, which one is more accurate? Which one is more consistent?

The team will test these different scenarios by using two different sets of code five times each. The data extraction tool will be used to collect data comparing time versus energy. For consistency, the team will look at how many times each scenario stops properly at the gate. For both consistency and accuracy, qualitative observations will be recorded to use as comparisons. The team members will use their own discretion is determining which set of code is more consistent and accurate for the task at hand.

Task-

Figure 10. AEV Track

The task that the AEV is trying to complete in both types of code is to travel from the loading dock to the gate, trigger the gate, wait for seven seconds, and proceed through the gate. In order to trigger the gate, the AEV must pass the first sensor but cannot pass the second sensor because it will cause the gate to shut. The gate opens seven seconds after the gate is triggered so the AEV must wait that amount of time.

Power Braking Code-

  /*

   * MISSION CRITICAL MEASUREMENTS:

   * Distance from level_1 to slope_1:       6 ft 72 in 147.692 marks

Distance from slope_1 to level_2: N/A 48.042 in 98.548 marks

OPTIMAL STOPPING POSITION: (target – 3 inches) = 82.051 marks

Distance from level_2 to gate_stop: N/A 43 in   88.205 marks

Distance from gate_stop to slope_2: N/A 53 in   108.718 marks

Distance from slope_2 to level_3: N/A 48.01  in 98.482 marks

Distance from level_3 to end:   6 ft 72 in 147.692 marks

Inches to Marks: 0.4875in /  Mark

Marks = inches/.4875in

   */

 //Reversing the motor direction to compensate for the starting orientation of AEV.

 reverse(4);

 // 1. Set motor speed of all motors to 30% & run for approximately 147 marks from start to beginning of the first incline.

 motorSpeed(4, 30);

 goToRelativePosition(147.692);

 // 2. Increase motor speed of all motors by 5% (to 35%) to compensate for incline & run for approximately 98 marks to the end of the first incline/beginning of the gate plateau.

 motorSpeed(4, 35);

 goToRelativePosition(98.548);

 // 3. Continue running motors at same power for approximately 25 marks. Reverse all motors & increase motor speed to 40% power & run for .75 seconds to power brake the AEV.

 //    Reverse motor direction again to restore initial direction of movement, brake all motors & have AEV sit still for 8 seconds to allow the gate to open.

 goToRelativePosition(25.051);

 reverse(4);

 motorSpeed(4, 40);

 goFor(.75);

 reverse(4);

 brake(4);

 goFor(8);

 // 4. Increase motor speed of all motors to 25% & run for approximately 100 marks to pass through the gate to about the peak of the second incline.

 motorSpeed(4, 25);

 goToRelativePosition(100);

Coasting/Power Braking Code-

 //Reversing the motor direction to compensate for the starting orientation of AEV.

 reverse(4);

 // 1. Set motor speed of all motors to 30% & run for approximately 147 marks from start to beginning of the first incline.

 motorSpeed(4, 30);

 goToRelativePosition(147.692);

 // 2. Increase motor speed of all motors by 5% (to 35%) to compensate for incline & run for approximately 98 marks to the end of the first incline/beginning of the gate plateau.

 motorSpeed(4, 35);

 goToRelativePosition(98);

 // 3B.  brake all motors to coast AEV close to optimal stopping point & power brake by reversing direction, setting motor speed to 20% and run for .6 seconds, then reverse the direction of all motors, brake them all & wait 8 seconds for the gate to open.

 brake(4);

 goToRelativePosition(46);

 reverse(4);

 motorSpeed(4, 20);

 goFor(.6);

 reverse(4);

 brake(4);

 goFor(8);

 // 4.  Increase motor speed of all motors to 25% & run for approximately 100 marks to pass through the gate to about the peak of the second incline.

 motorSpeed(4, 25);

 goToRelativePosition(100);

Procedure-

1. The power braking code will be uploaded to the Arduino and the data extraction tool will be open on one of the team members desktop. For descriptive directions on how to use the data extraction tool, see Figure 2.
2. The first five trails will be run using the power braking code. For each run, the AEV will be started with the front wheel on the green tape. One team member will be standing near the starting gate. The team member standing at the starting dock will start the AEV.
3. When the AEV is waiting 7 seconds at the gate, one team member will quickly observe the location of the AEV inside the gate region. These observations will be used to compare consistency.
4. After the AEV completes its run, the AEV will be carefully lifted off the track. The Arduino will be plugged back into the desktop computer and the data extraction tool will be run.
5. After the data extraction tool successfully transfers the data to an Excel file, the reset button on the Arduino will be pressed so the AEV can be run again using the same code. The Excel files containing the data will be used to create graphs of time versus energy.
6. After the five trials for the power braking code are completed and data is collected, steps 1 through 5 will be repeated using the coasting/power braking code.

Figure 11. Data Extraction Tool Instructions

Data-

Figure 12. Trial 1 Data Graphed

Figure 13. Trial 2 Data Graphed

Figure 14. Trial 3 Data Graphed

Figure 15. Trial 4 Data Graphed

Figure 16. Trial 5 Data Graphed

Figure 17. Trial 6 Data Graphed

Figure 18. Trial 7 Data Graphed

Figure 19. Trial 8 Data Graphed

Figure 20. Trial 9 Data Graphed

Figure 21. Trial 10 Data Graphed

Data Analysis-

Figure 22. Trial Number versus Time of Run

Figure 23. Trial Number versus Energy Consumption

Conclusion of Data- The trials run with the power braking code resulted in more power usage of the AEV and therefore resulted in a higher cost for energy consumption. The trials run with the coasting/power braking code resulted in less power usage and therefore resulted in a lower cost for energy consumption. The trials run with the power braking code resulted in a lower run time and therefore resulted in a lower cost for run time. The trails run with the coasting/power braking code resulted in a higher run time and therefore resulted in a higher cost for run time. The trails run with the power braking code were significantly more consistent and accurate in completing the run successfully than the trials run with the coasting/power braking code. Additionally, the trials run with the power braking code were more consistent in terms of run time and energy consumption between runs.

Implementation- It is advised that the team continue to use the power braking code because of the major differences in accuracy and consistency of the AEV. The overall task of the AEV is to reliably and safely transport passengers to the two different docks, so accuracy and completion of runs is important. In respect to budget, the safety and accuracy of the AEV’s runs are also a factor to the budget. If extra money is spent on the energy consumed in the run, the team can balanced out the spending by the safety and accuracy aspects of the budget.

Original Test Questions and Answers-

1. For our current code for performance test 1 which uses power braking, what is the energy consumption?
   1. The average energy consumption for the trails run with the power braking code was 117.72J.
2. If the code for performance test 1 is modified to stop the motors to coast to stop then use a small amount of power braking, what is the energy consumption?
   1. The average energy consumption for the trials run with the coasting/power braking code was 102.08J.
3. For the two different scenarios, which one is more accurate? Which one is more consistent?
   1. The trials run with the power braking code were significantly more accurate than the trials run with the coasting/power braking code.