CDR

CDR

 

Submitted To:

Instructor: Dr. Bixler

GTA: Isabel Fernandez

 

Created By:

Team B:

Jean-Pierre DeDeaux

Aaron Foster

Caden Pfendler

Andrew Reade

 

Engineering 1182

The Ohio State University

Columbus, OH

April 20, 2018

 

Abstract

Purpose

Having labs throughout the semester brought an understanding of the design process that was needed to execute the construction of the AEV. The purpose was to have a sort of application into the real world and how projects, design processes, and working more independently to complete the AEV. The report will go in depth in both the preliminary and advanced research and development. Following is the performance tests to the final performance test/final run. Having goals segmented in lab immensely helped the flow of the process of completing the AEV. Being able to complete a simple goal like building a testing AEV at the start and being able to build from every goal completed makes the process more manageable, rewarding, and results in a better qualitative output of the work put in.

Results

The design processes lead the group to decide on a design that would be more practical in a real-life application, siding on control, balance, and space for passengers. This more practical design was then used in every further research and development, where as a group, concluded a best configuration of this design. The final results were that the AEV design was heavy and consumed power but was easy to manipulate with the code and resulted in a perfect, clean and controlled final run.

Recommendations

Based on preliminary research and development, having two motors with two propellers each introduced a higher efficiency. Having the motors further away from the center of mass resulted in better distance with the same power output. The design recommendations would follow in a balanced, heavier and controllable design that would allow a more transparent application to thee task given.

 

Introduction

 

The purpose of the labs is to test different designs of the AEV and find the best design that will most effectively complete the objective. The objective is to create an AEV that can safely and efficiently transport passengers from Linden to Easton or Polaris. The process to complete this objective was done through multiple tests during labs: what configuration the propellers should be formatted in, how the motors should be oriented on the AEV, whether or not the reflectance sensors be used, and the overall design of the AEV. This report will show what AEV design was most effective and the steps the group went through to come to their conclusion.

 

Experimental Methodology

 

The objective of is to have the AEV start in the drop-off zone, move to the gate and stop at the first sensor without reaching the second, wait seven seconds then move through the gate. The AEV then must move to the loading zone, connect with a caboose and go back through the gate, following the same parameters as previously stated, and end at the drop-off zone.

 

The first test that Group B completed was determining the propeller configuration. The group tested multiple configurations to decide whether to have the propellers stacked on top of one another and parallel (Figure 1), stacked and perpendicular (Figure 2), and whether to have one set of propellers facing the opposite direction (Figures 3, 4). This was done by collecting data using a Power vs. Distance graph.

 

Next, the group tested the motor configuration to determine where to place the motors on the AEV. The first configuration had both motors on the sides of the AEV, with both pushing the same direction to go either forward or backward (Figure 7). The second configuration moved the motors closer together, so that they were both on the underside of the AEV, with both of the motors functioning the same as the first configuration (Figure 8). Following the testing of motor configuration, the reliability of the reflectance sensors were tested. To complete this test the group coded the AEV to move a certain amount of marks, ran it multiple times on the track and observed the AEV to see if it would end in the same spot. The team would then measure the amount of error that resulted from each run to determine the reliability. Finally, the group tested two complete designs that were created. The Group ran both designs on the track multiple times to decide what design was most consistent and easiest to code and control.

The group then proceeded to the performance tests, the first of which consisted of starting in the drop-off zone, moving to the gate and stopping at the first sensor without reaching the second, waiting seven seconds, then moving through the gate. The second performance test had the same requirements, then tasked that the AEV proceed down the incline, stop in the loading zone to pick up the caboose, wait for at least five seconds, then leave the loading zone. The third and final test continued added that the AEV, with the caboose, reach the first sensor without touching the next, staying between them for seven or more seconds, then proceeding through the open gate to the drop-off zone, where it would stop.

 

Results

 

The motors were the first test the group did. After generating multiple concepts for the configurations, and finally settling on and testing four final designs, the data from the arduino was collected and compiled into a graph which allowed the group to visualize the results. Two total graphs were made, comparing distance versus time as well as power versus time. The four propellor designs were extremely similar in power output of about 28 Watts (Figure 5, below). However, the four different configurations had contrastingly different results in distance travelled. The second propellor configuration (Figure 2) traveled the farthest distance, at about .6 meters, far greater than that traveled by the third and fourth configurations (Figures 3, 4), which went .4 and .44 meters, respectively, as seen in Figure 6. Comparing the results from the multiple tests, the group decided to use the second configuration on their final AEV design. This conclusion was made due to the configurations consuming the same power, however the second one traveled farthest.

 

Figure 5: Graph of Power vs. Time for Propeller Configurations

 

Figure 6: Graph of Power vs. Distance for Propeller Configurations

 

Similar to the  propellers, the group ran the same tests for two different motor configurations. The data was collected and compiled into the same graphs as the propellor tests. The first configuration, with the two motors farther apart, used slightly less power (about 42 Watts) than the second motor configuration (about 44 Watts), which had the motors closer together (Figure 9). The first configuration also went farther than the second configuration in both the forward and backward tests, by about .7 meters in each direction (Figure 10). Thus, the group chose the first motor configuration for the final AEV.

 

Figure 9: Graph of Power vs. Time for Motor Configurations

 

Figure 10: Graph of Power vs. Distance for Motor Configurations

 

The final test the group ran was using two different body designs. The group tested a wide and narrow design for their AEV. Graphs were created, similar to those of the motor and propellor tests. The narrow design was lighter, but had less surface area than the wide design, which made fitting all of the components onto it difficult. It also resulted in less room for passengers to sit. This design used less power and went further with the same code for the motors; however, it was highly inconsistent and was hard to get to go the same distance every time using the same code. The wider body, though slower and slightly more power consuming, was more effective at carrying passengers as well as being easier to assemble the individual parts of the AEV onto such as the battery and Arduino. This body was also far more consistent. For these reasons, the group decided to use the wide body for their final AEV design.

 

            During performance test 1 the group was still getting used to coding the Arduino, thus many trials were done to perfect the timing of the motors turning on, off, as well as test braking versus coasting. The group chose to use the goFor() and motorSpeed() commands to perform the tasks required of the AEV. These commands were chosen over the absolute and relative position commands because the group noticed that many times this command was unreliable due to the differences that greatly affected the consistency of the reflectance sensors, such as lighting. The group also initially chose to use coasting as the preferred method of stopping, which reduced overall cost of the AEV by decreasing power usage. The group completed the first performance test with a perfect score. Continuing off the first performance test, the second test further challenged the group’s ability to have a constant and reliable code which would allow the AEV to complete the track flawlessly each time. However, many problems presented themselves during this test. First of all the group noticed that there were minute differences between the tracks on the second and third floors, which required the group to make different codes for each floor. The group also noticed that the AEV’s performance became varied after an accident in which the AEV fell off the track. In response to the new inconsistencies, the group was required to make small changed in the code, such as motor speed and time after many tests. The group also implemented power breaking in order to decrease the variance in the coasting distance. Though the AEV presented many problems during this test, the group was still able to complete all of the tasks with a perfect score. On the final performance test the group ran into similar problems with consistency and similar solutions were put into action to ensure that the AEV was able to go through the track. Over all the group was very happy with the AEV’s performance. The overall cost of the AEV was $516,000 and used roughly 322 Watts of power [Figures 11 – 12].

.

 

Figure 11: Power vs. Time Graph for Final Performance Test

 

Figure 12: Graph of Power vs. Distance for Final Performance Test

 

Discussion

 

Initially, the group used concept screening to generate and evaluate proposed AEV designs by each group member. Initially the AEV was judged on how safe it was, size, weight, and  the number of propellers and motors. The group that decided the larger the AEV was, the more room it had for passengers and safety features. The AEV would score higher if it was lighter weight and had more motors and propellers. Aaron and Andrew’s designs were chosen to move onto the concept scoring as they scored highest in the initial categories [Figure 13]. The second analysis of the designs was more in depth and faced harsh criticism, as well as a complex scoring process [Figure 14]. The categories for the concept scoring were high versatility, safety, an ergonomic and aesthetically pleasing design, durable body and material, easy and cheap to develop, and stable on the track. Over all, Aaron’s design ranked the highest, and thus was used on the final AEV design which the group would create and test.

 

During the testing of the propeller configurations, designs 3 and 4, which had one set of propellers facing backwards, consistently travelled a much shorter distance than configurations 1 and 2, which had all propellers facing the same direction (Figures 1,2,  3,4). During the motor configuration tests, the first design was more efficient due to using less power during the tests, as well as travelling further than the second configuration in both the forward and backward tests.

 

The main sources of error that arose in testing the AEV were the placement on the track as well as the parts on the AEV being out of place, namely the propellers becoming misaligned after a run; these are fixed by placing the AEV at the marked starting position on the track, to ensure a constant starting position, and by examining the AEV prior to a run to ensure all parts are in place and aligned. Another error that arose later was the AEV stopping in the right position, as sometimes it would not come to a complete stop and instead coast past the second sensor during the performance tests. This was fixed by testing the AEV to determine how long the propellers needed to run for to ensure a complete stop.

 

The final test the group ran was using two different body designs. The group tested a wide and narrow design for their AEV. The narrow design was lighter, but had less surface area than the wide design, which made fitting all of the components onto it difficult. It also resulted in less room for passengers to sit. This design used less power and went further with the same code for the motors; however, it was highly inconsistent and was hard to get to go the same distance every time using the same code. The wider body, though slower and slightly more power consuming, was more effective at carrying passengers as well as being easier to assemble the individual parts of the AEV onto. This body was also far more consistent. For these reasons, the group decided to use the wide body for their final AEV design.

 

During the AEV’s runs on the track, the AEV did not appear to wobble or have any trouble going over the slope on the track, after it was properly programmed. Because there are no brakes present on Group B’s AEV, the propellers must be reversed to stop the vehicle. The vehicle also comes to complete stop between the gates, rather than coasting in.

 

Conclusions and Recommendations

 

Summary

 

The main purpose of this experiment was to test and define the best configurations of the motors and propellers in order to use power more efficiently. The goal of the AEV project is to complete the run in proper fashion, but to also consume the least amount of power. The AEV was tested in one design with multiple configurations as well as two runs with two designs with the same propeller configuration. Based on the results the configuration that used the least amount of power was configuration 1. This is assumed to be derive from the distance away from the monorail the motors were as well as the way the propellers were facing. The propellers pull and push with different force, so the differences in configurations that may look the same but have drastically different outcomes are due to the orientation of the propellers.

 

Conclusions

 

The purpose of the labs is to test different designs of the AEV and find the best design that will most effectively complete the objective. The main goal of the experiment was to find the best configuration that uses the least amount of power as possible. Configuration 1 was deemed the best because it used the least amount of power while being able to travel the farthest as well. (Figures 6, 10) Knowing which are more efficient in the use of power is vital to know because on a larger scale as well as repeated travels of this monorail transportation vehicle, the small difference in the experiment can be extrapolated into a larger and more costly demise to the design compared to others that may be better at using power.

 

Resolving error

 

The possible sources of error would be that the starting position of the AEV could be changed slightly form run to run which, the propellers may have had induced friction with the motors if they were in contact with it which is highly likely, the wheels on the monorail may have had more friction in certain runs and the speed in which the wheels were moving may have increased friction. The start of each AEV run should have been started at the same spot, and likely were. The propellers, are confined to a small space due to the use of two on each motor, which means 3D printing propellers would be the most ideal solution moving forward. The wheels and the friction acting on them them could be solved by using a lubricant on the ball bearings, which will allow the wheels to move effortlessly without the hassle of friction creating random anomalies in runs. The group also resolved the inconsistencies of the code by using power breaking instead of coasting, to reduce variation in distance traveled, as well as constantly tweaking the code after the run to maximize motor efficiency.

 

Recommendations

 

The AEV ran the the best in configuration 1, as well as consumed less power in the distance that it traveled, therefore the recommended configuration of the AEV for Group B is configuration 1. This configuration was the first prototype of the AEV and was used to test various runs and types of code previous to this lab experiment. Moving forward this configuration would be best suited to trial test any labs and experiments that would need to be completed in order to achieve the best run possible of the AEV for group B.

 

Reasons for incompleteness

 

With the knowledge gained from this lab, Group B has decided that a lighter and less material heave AEV would be most effective. The group would ideally have 3D printed propellers and chassis to maximise surface area and power with minimal weight. The group noticed that dropping the AEV could have caused many of the problems they were facing and given the chance to redo this lab, would have implemented better safety precautions.

 

Appendix

Figure 1: Propeller Configuration 1

Figure 2: Propeller Configuration 2

 

Figure 3: Propeller Configuration 3

 

Figure 4: Propeller Configuration 4

 

Figure 5: Graph of Power vs. Time for Propeller Configurations

 

Figure 6: Graph of Power vs. Distance for Propeller Configurations

 

Figure 7: Motor Configuration 1

 

Figure 8: Motor Configuration 2

 

Figure 11: Final AEV Design 1

 

Figure 12: Design 2

 

Figure 13: Concept Screening

 

Figure 14: Concept Scoring

 

Schedule

 

Andrew Reade

-Lead programmer

-Create code that will allow the group to test within conditions of the final test runs

-Create secondary code to run AEV

Jean-Pierre DeDeaux

-Run through the past designs and consult group to meticulously pick best configuration of current design

Caden Pfendler

-Help develop code for the AEV runs

-Critically think ahead for overall AEV code that needs to be written for complete run

Aaron Foster

-Help and overall manage configuration of AEV as group sees fit

-hypothesize numbers for motors and time to create best possible run for AEV

 

Meeting #1

Date:1/10/2018

Time:1:30 in lab

Members Present:All

Topics Discussed:

  • Introduced ourselves to become familiar with  the team.
  • Exchanged phone numbers.
  • Started making plan for how we will work on the AEV project for the semester.

Meeting #2

Date: 1/17/2018

Time: 12:45 – 2:05 in lab

Members Present: Andrew Reade, Jean-Pierre DeDeaux, Caden Pfendler

Topics Discussed:

  • Introduced ourselves to to newest team member.
  • Began working on Preliminary R&D
  • Finished work and code on exercises one and two.

Meeting #3

Date: 1/24/2018

Time: 12:45 – 2:05 in lab

Members Present: All

Topics Discussed:

  • Resumed work on Preliminary R&D
  • Completed Website Update 1 before class, and ensured it was completed.
  • Asked Aaron to draw the final concept for our AEV and assemble it.

Meeting #4

Date: 1/31/2018

Time: 12:45 – 2:05 in lab

Members Present: All

Topics Discussed:

  • Finished work on Preliminary R&D.
  • Agreed on a final design for the AEV.

Meeting #5

Date: 2/7/2018

Time: 12:45 – 2:05 in lab

Members Present: All

Topics Discussed:

  • Began work on Advanced R&D, with our topic being the propeller configuration.
  • Determined a configuration that gave equal power when both pushing and pulling.

Meeting #6

 

Date: 2/13/2018

Time: 3:00 – 4:45 in 18th Avenue Library

Members Present: All

Topics Discussed:

  • Designed part for the Grant Proposal.
  • Discussed roles for each member in the Committee Meeting.

Meeting #7

Date: 3/6/2018

Time: 7:30 – 8:30 in 18th Avenue Library

Members Present: Jean-Pierre DeDeaux, Aaron Foster, Andrew Reade

Topics Discussed:

  • Worked on Progress Report 2.
  • Discussed what we will work on In Lab 9a.