Evolution of Design

Design brainstorming and determination:

AEV Theme: Space

AEV feature we will be focused on altering: arm

Group D’s guided topics: battery testing & coasting vs power braking

 

Josh’s Design:

  • Meant to improve aerodynamics, as well as move around certain parts

Alicia’s Design:

  • make AEV more exciting and add better aerodynamics

Megan’s Design:

  •  Make better aerodynamics, and make AEV look better

Pauls Design: (design used for grant proposal, and chosen one amongst the group)

  • meant to spread out fans, as well as improve balance

Design Decisions and Grant proposal

Solid works draft pictures and gif:

 

 

 

 

Reflectance sensors:

Purpose of these sensors is to track the distance the AEV moves in marks, in order to allow for distance based coding.

Codes used throughout:

  1. Code for reflectance test:
    1. reflectanceSensorTest( );
    2. View serial monitor
  2. Code for Test run:
    1. celerate(4,0,25,3) – accelerates all motors from 0 to 25 in 3 seconds
    2. motorSpeed(4,25) – go at speed of 25 on all motors
    3. goFor(1) – for one second ^
    4. motorSpeed(4,20) – run all motors at 20
    5. goFor(2) – for two seconds^
    6. reverse(4) – reverse all motors
    7. motorSpeed(4,25) – run all motors at 25 power
    8. goFor(2) – for two seconds^
    9. brake(4) –  brakes all engines
  3. Data From Test run

 

Cods is working as intended, and outside of some outlier points, the performance of the AEV was correct and expected

Code for aR&D 1

//run all motors at 25% power  for 125 marks

motorSpeed(4,25);

goToRelativePosition(125);

 

//run all motors at 30% power for  125 marks

motorSpeed(4,30);

goToRelativePosition(125);

 

//run all motors at  35% power for 125 marks

motorSpeed(4,35);

goToRelativePosition(125);

Code for aR&D 2

//run  all motors at 30% power for 40 marks

motorSpeed(4,30);

goToRelativePosition(40);

 

//run all motors at 30% power for 50 marks

motorSpeed(4,30);

goToRelativePosition(50);

Code for successful run of performance test 1

// Run all motors at a constant speed (23% power) to 122 marks

 motorSpeed(4,23);

 goToRelativePosition(122);

 //Brake all motors at 20 marks, then reverse

 brake(4);

 goToRelativePosition(16);

 reverse(4);

 //Run all motors at a constant speed (15% power) for 1.5 seconds

 motorSpeed(4,20);

 goFor(1.5);

 //Brake all motors for 7 seconds

 brake(4);

 goFor(7);

 //Reverse all motors, then run at a constant speed (25% power) to 40 marks

 reverse(4);

 motorSpeed(4,25);

 goToRelativePosition(40);

Design Considerations

  1. Design observations: (current design is Sample AEV 1)
    1. Thus far, only the sample design has been tested
    2. Seems to work fine, very simplistic and clunky
    3. Balance concerns when on track as wheels aren’t centered
    4. Battery adding and size make it slow to begin testing in a given period
  2. Research and future design considerations.
    1. Wheels need to be over the battery/Arduino, which is the center of mass,  so that it is balanced and doesn’t wobble
    2. Need battery mounting to be separate from tower mounting so we don’t have to take it apart each time.
    3. Minimizing weight is key to making the AEV require less power
    4. Keeping mass as close to wheels as possible, as that makes the AEV easier to begin moving
    5. Test and research needed:
      1. alternative battery bracket
      2. stacked fans
      3. reposition main tower

Advanced Research and Development

aR&D 1: Coasting test

  1. Takeaways from coasting test:
    1. As the speed increased by 5%, the AEV coasts 20.7 inches farther on average.
    2. As speed increases, the successive gains in distance coasted decreases.
    3. At a constant speed, changing distance has very little effect on coasting, only changing by about the difference in powered distance.
  2. Supporting research:
    1. 2.   3.

Graph 1 shows how the AEV travels over a constant powered distance of  25% power for 125 marks, resulting in a final position of 249 marks, meaning 124 marks coasted
Graph 2 shows how the AEV travels over a constant powered distance of  30% power for 125 marks, resulting in a final position of 307 marks, meaning 182 marks coasted
Graph 3 shows how the AEV travels over a constant powered distance of  35% power for 125 marks, resulting in a final position of 336 marks, meaning 211 marks coasted

Power: 25% 30% 35%
Distance Coasted: 124 marks 182 marks 211 marks

Table summarizing all the data gathered, at a powered distance of 125 marks

 

Distance Powered: 91 marks 106 marks 125 marks
Distance Coasted: 180 marks 201 marks 216 marks

Table showing how distance coasted changes with changing powered distance, at 30% power

3. What this does for the future:

  1. This proves to the team that coasting is hardly a feasible option in terms of performance tests as the AEV has so little friction that the coasting is way too long to be practical.
  2. Shows how even at 25% power, it coasts for nearly 20 inches, which is not only wildly inconsistent, but proves the need to power break
  3. That for smaller sections, changing the distance and coasting might be useful, as the distance coasted has a high correlation with the distance powered
  4. This makes the AEV more marketable as with this information, we will use less coasting, and the resulting power breaking that will need to be done will lead to a more crisp, clean performance run, look more controlled on track, and reduce the inconsistencies across runs by a lot.

aR&D 2: Battery tests

  1. Takeaways from this test
    1. During the course of one lab period (approximately 55 minutes), the battery voltage decreased by approximately 0.01 Volts.
    2. The amount of distance the AEV traveled did not have a significant impact on the battery voltage, however, as the AEV is powered for more distance, the voltage decreases faster over time
  2. Supporting research

1.  2.

Graph 1 shows the voltage decrease over 40 marks at 30% power, with an average voltage of 8.141 Volts, and a slope of -.0116 Volts/second

Graph 2 shows the voltage decrease over 50 marks at 30% power, with an average voltage of 8.134 Volts, and a slope of -.0219 Volts/second

 

NOTE: as the 40 mark test was conducted earlier in a testing day than the 50 mark test, the .007 Volt decrease is a result of  battery drain over time, and is indicative of how the voltage decreases after successive runs

3. Future looking plans with this data

  1. This data shows how energy is consumed over an AEV run,  meaning it dictates how we run out AEV on the final run to conserve energy
  2. One takeaway from this is that the voltage decreases no matter what as you use the battery over a day
  3. Also, that the voltage will decrease over a run of the AEV, as the AEV is being powered, meaning long runs and distances are preferred, as these will use less voltage
  4. Overall, this proves that around 8 Volts are used a second, which slightly decreases over a run, which should enable the team to predict the energy used for the final performance test