Preliminary Design Review

 

Preliminary Design Review Report

Submitted to:

Inst. Krista Kecskemety

GTA Isa Fernandez Puentes

Created by:

Team E

Alejandra Martinez

Madeleine Mears

Lauren Sara

Beth Wiberg

Engineering 1182

The Ohio State University

Columbus, Ohio

24, March 2017

Executive summary

 

The entirety of the Advanced Energy Vehicle project incorporates beneficial concepts such as planning, preliminary testing, design elements, and teamwork that will be important in the future work of engineers.  The overall purpose of the project is to design a vehicle along with a code to run the machine, that will operate smoothly and consistently, is energy efficient and has a minimal energy to mass ratio.  The monorail vehicle is to be designed for an unnamed client, and by client demand, is required to have the capability of picking up cargo, like R2D2’s and transport itself and the extra weight along a track.  The vehicle must be able to run along the track, smoothly stop at a gate for seven seconds, and then continue running until the end of the track.  Upon arriving at the end of the track, it must attach itself with a magnet to another vehicle, and then reverse directions to take itself and the cargo back to its original starting position.

Over these past weeks, the labors of Group E’s work have been great, but minimal quality results have come out of the effort.  The code was established early on in the AEV project.  Upon uploading the program to the vehicle and testing it’s run, the monorail failed to move due to issues with the sensors.  Continued issues with the sensors have slightly hindered Group E’s progress in relation to running the vehicle on the track and completing test runs.  However, the problem has recently been resolved.  In relation to the design process, the arduino and the battery will be encased inside of a hollow kite-shaped outline.  The vehicle will be taller than it is wide.  Group E came up with this idea through researching efficient aircraft designs.  This current design is lightweight and very minimalistic so as not to affect the balance of the monorail.  The Group is in the process of figuring out how to reduce the swaying of the vehicle as it runs on the track.  As Group E progresses into the final weeks of the project, the focus will be on increasing the power put in the code so the vehicle will be able to move on the track, and getting down the specifications of distance, time and consistent running to perfect the AEV run for the final performance.    

 

Table Of Contents

 

Introduction ……………………………………………………………………………………………………3

Experimental Methodology …………………………………………………………..4

Results…………………………………………………………………………………………8

Discussion……………………………………………………………………………………11

Conclusion & Recommendations……………………………………………………13

Appendix……………………………………………………………………………………..14

 

Introduction

 

The objective of this lab was to develop a code and create a vehicle that runs consistently, efficiently and has a low energy to mass ratio.  The code that has been developed for this project is based more on distance than time right now.  Through developing the code, the group has realized that it requires much trial and error in testing the code on the actual track and adjusting minute details of it to perfect the movement and timing of the vehicle.  It started off at a significantly low power with minimal results.  The vehicle did not move until the power was increased.  After the vehicle began to move, which did not happen until recently because of a broken sensor, the results of the run were able to be downloaded, analyzed and put into a phase graph.  The phase graph also identified important information about the vehicle design.  The design the group came up with is a generally minimalistic prototype.  Unfortunately the 3-D printed version of the design has not been applied to the vehicle yet, however the AEV has been running to its full potential.

 

Experimental Methodology

In labs 1 and 2a the main objectives were to familiarize the group with the arduino and how to program it as well the rest of the lab equipment. This was accomplished in lab 1 by learning the different parts of the AEV Controller such as where the on/off switch and the USB connection is. The group next learned different function calls that are helpful to use when programming the AEV. These calls included the celerate(m,p1,p2,dt), motorSpeed(m,p), goFor(dt), brake(m), and reverse(m) calls. The team then split up to complete scenarios 1 and 2 which consisted of a list of commands the group was to program the arduino to do. In lab 2a the group’s primary objective was to become familiar with the external hardware components. Prior to lab, group members assembled the sample AEV to use. The group then installed and tested the external sensors. In order to do this, it was crucial that the group learned the function calls for the sensors. These calls goToRelativePosition(m) and goToAbsolutePosition(m). The group then designed a program that would run the AEV for various speeds and times. The group ran the code and showed a TA in order to complete the lab.

In lab 2b the main objective was for the group to become familiar with the propulsion system and the wind tunnel testing system. This was accomplished by first having a group member record data from the wind tunnel user the propellers of a 3030 puller and pusher, 2510 puller and pusher and a 3020 puller. Using the data from the wind tunnel the group was able to calculate the current, thrust scale reading, rates per minute at various arduino power setting percentages.

In labs 4 and 5, the main objectives were to brainstorm various aspects of an efficient AEV and use various methods of decision making to draw conclusions as to what a possible design can look at. Initially, each member of the group researched independently different aspects of air vehicles that they thought were important to include in a design. Each member then had the responsibility to draw their design.

After completing the sketches, the group reconnected and each member had an opportunity to discuss their own drawing and the aspects of the design they felt was necessary to include in the final design. The group collaborated and troubleshooted all possible design ideas before completing a team design.

The group used scoring matrices and assigning value to different aspects of the design in order to determine what were the most important things to have in the design.

The majority of lab 4 was spent creating a test run code and then downloading Arduino EEPROM Data into a Matlab file to graph and distinguish what’s happening at various times in terms of the power used. In order to accomplish this, the group had to convert the EEPROM data into physical parameters using given equations in an excel file. A Performance Analysis was then completed using the calculated data. The main objectives of lab 4a were carried over into lab 4b by continuing to work on the Matlab file and continue working on uploading the data into the design analysis tool.

Lab 5 consisted on creating Concept Screening Scoresheets and a Concept Scoring Matrix to use to evaluate the different aspects of a design. The group determined all of the important features of a successful design and determined the weight of each aspect. Then, each design was evaluated using the matrix and was adjusted to a weighted score to see which design had the highest score and was, in theory, the most successful design. After doing this, the group was able to design a 3D part to be printed that would enhance the current design. The preliminary design was then finalized and the group was able to begin testing the design and redesigning the code.

At the halfway point, the group was responsible for giving an Oral PDR presentation to part of the class. This presentation was successful and the group was able to articulate all of the progress that has been made throughout the semester. Following the presentation, the group has focused the goals of lab time to be to create a precise code. The 3D part is in the process of being printed so up until then the group has designed the AEV to be the closest to how it will be with the part.

 

Results

In order for the team to come up with a final design each member did their own researching and created their ideal design. After a group discussion presenting ideas to each others, certain values and parts of the design were decided on. The group decided on a vertical design rather than the traditional horizontal approach. This decision was to create a more aerodynamic design and energy efficient shape of the AEV. The final design includes a skeleton like shell that encases the Arduino, motor and other essential parts. This design created in SolidWorks can be seen below.

Due to the large demand for 3D printed parts for AEV designs, the part needed to complete the design has not been created yet. the team decided to conduct tests and continue to work on completing the code without the 3D printed body piece. As a result of this major setback, the team only had time to test one design. However, in the future the team plans to test a second deign to compare their phase diagrams and performance. The second design will entail the same body structure of the AEV but entail different propeller combinations. The design currently being tested has two 3030 pusher propellers on the back of the vehicle, the second design will have one 3030 pusher propeller and a 3030 puller propeller. The drawings for these drawings can be seen in figures 1 and 2 in the appendix. The reasoning for this design is for the AEV to potentially be more efficient on its return trip. The group will also complete another comparison test with the main 3D printed body piece on the AEV versus the AEV without the the structure. Although the group was not able to compare two designs, the current design can be compared to the original structure provided in the lab manual. The phase change graphs for the horizontal configuration of the AEV and the AEV’s current configurations can be seen below.

Compared to the initial horizontal design, the current design being tested has more phases due to more commands delivered to the vehicle. The new phases also contribute to more power being produced. The main goal of the AEV is for the vehicle to produce as little power as possible to maintain energy efficiency. The supplied power for the latest design is a lot greater than the horizontal design, in the future the team must find different alternatives to make the vehicle as efficient as possible. The new design accomplishes the tasks closer than the horizontal design and will developed to also be energy efficient.

The new vertical design approach has many properties that allow it to accomplish the tasks necessary better than the previous horizontal. Due to the new changes in design and code efficiency, the new AEV design uses minimal energy compared to the original horizontal design. The figures comparing the two design’s energy as the code was completed can be found in the appendix.The team hopes to continue this low energy principle in the final design in order to create the most environmentally conscious vehicle.

In lab 2, different propeller types were testing in a wind turbine for teams to be able to determine the best possible propeller configurations for their final design. The figure seen below shows a graph of the propulsion efficiency as advance ratio increases. The dark blue 3030 pusher and purple 3030 puller propellers produce the greatest amount of advance ratio as the propulsion efficiency is increased. The team has decided to use the 3030 pusher propellers in their current design due to this data collected in lab. However, in the future, the team will adjust the propellers on the AEV design to contain one 3030 puller and 3030 pusher. This potential design will be tested against using both 3030 pusher or 3030 puller propellers.

 

Discussion

One of the team’s main priorities has been to create the most efficient design that benefits many important features that will contribute to the AEV’s success. Due to the inability to test a second design as discussed in previous sections, the team compared the new design to the first horizontal setup provided in the lab manual. The table that encompasses the screening and scoring matrices can be seen below.

 

The team used key principles that would help the AEV complete the desired tasks to compare the two designs. From the data above, the second vertical design turned out to be a better fit than the original horizontal design. However, there are still parts of the design that need to be improved upon including the durability, cost, maintenance, balance and environmental factors. The screening and scoring matrices will be used in the future to compare the design with the pusher and puller propellers and the design with the 3D printed body part. When asked if the new design would be continued for the final test, the team decided that the design did have potential but still needs to be developed and further tested amongst other designs before a final decision is made.

Throughout this process, there have been many instances where there was the potential for error. The lighting in the lab room is different than the lighting in the classroom and can therefore affect the sensors. Additionally, if the sensors were not directly positioned where they would be able to get a reading, the AEV would not move completely correct. Group E specifically, ran into errors concerning the lab equipment. The group determined late on that at least one of the sensors was malfunctioning. This was discovered because the AEV would not run as the code dictated. Once this was determined, the arm was accidentally broken so it had to be replaced, lastly, a wire connecting the sensors broke off and had to be fixed by a GTA. After all of these errors were resolved, the team has become more successful in garnering data from test runs and having the AEV move much more precisely.

Group E has only coded the AEV to approach the first gate. When the AEV runs, it successfully brakes and will stop directly parallel to the sensor. The next steps the group needs to take is to code the AEV to stop for seven seconds until the gate raises and go around the second half of the track and pick up the R2D2. When compared to the theory,  the design emphasizes the main objectives of the lab, efficiency and communication. Throughout the design process, emphasis was placed on designing the AEV to be as lightweight as possible. When programming the AEV the least amount of energy is used to make it move to where it needs to be. Since the group has yet to complete an additional design, the current design can be most easily compared to the prototype design that was created in the beginning of the semester. The designs are very different. The current design is a vertical design with the Arduino hanging perpendicular to the arm. In the prototype, the main body was horizontal and therefore parallel to the arm. Each design used a 3030 propellor as well as a push system. The decision to use a push system was decided from the data from the wind tunnel lab. The battery and arduino are on opposite sides of the design in order to evenly distribute the weight to ensure the AEV does not fly off the track. The group found through using the scoring matrices that the prototype only had a score of 21 on the matrix whereas the current design had a 26. In theory this means that the current design incorporates more crucial aspects of a successful design than that of the prototype.

Conclusion and Recommendations

Throughout various weeks of designing and testing, many decisions have been made to produce the current AEV design which the group has chosen to develop further. During the wind tunnel lab, different propellor configurations were tested. When thrust scale readings were compared to percent power, it was found that the 3030 Pusher configuration consistently produced the highest thrust scale reading after 10 percent power.  Propulsion efficiency and  advance ratio were also compared to reveal that the 3030 Pusher configuration produced highly efficient results between 15 and 50 percent power. After viewing these results, it was concluded that the group should aim to use the 3030 Pusher configuration in the final design.

The body of the AEV was designed with focuses on low mass and an aerodynamic shape. Following these focuses we designed a body that consists of a kite shaped frame which will contain the Arduino attached to two panels. The fame body reduces the amount of mass used to a minimal level while maintaining an aerodynamic, streamlined shape. The frame is currently in the process of being 3D printed. The group did not allot enough time for this process causing the testing procedures to fall behind. This issue was temporarily resolved by excluding the frame from the design being tested. In the future, the group will plan further ahead and allot more time for unfamiliar events to allow for unexpectedly prolonged procedures.

This design was compared to a basic design that consisted of a horizontal rectangular body where the Arduino and battery were both attached. Attached to the rectangular body were two wings and the arm from which the body hung. While this design was more balanced than the group design, the group design achieved the goal of a low mass body. The group used this information to further develop the design and improve the balance by adding nuts to the center body to better align the front and back panel to which the Arduino had been attached.    

The group is currently working with two possible designs leading to the final design. Design one, shown in Figure 1 in the appendix, consists of 2 3030 pusher propeller configurations, while design two, shown in Figure 2 of the appendix has one 3030 puller and one 3030 pusher configuration for a more efficient return after the cargo has been obtained.

The group managed to test the performance of design one. Due to a broken sensor, the group ran out of time and was unable to test the performance of design two. The group plans to designate time to complete Performance Test 1  during Performance Test 2. This has been included in the schedule and goals for the upcoming lab.

Appendix

 

Arduino Code

 reverse(4); // Pusher propellers, reverse all motors

 motorSpeed(4,40); // Set motor speed to 40%

 goToAbsolutePosition(225); // Run motors until absolute position of 225 marks

 brake(4); // Brake all motors

 goFor(13); // Allow brake time plus 7 seconds for gate to open

 

Schedule

Task	Group Member	Date Started	Date Due	Percent Done
Finish Performance Test 1	All	3/23	3/28	80%
Finish base code for rest of mission	All/ Alejandra	3/24	3/28	35%
Write Second Arduino code for Performance Test 2	All/ Alejandra	3/24	3/28	0%

 

Team Meeting Notes

Date: 03/23/17

Time: 9:16 PM (group message)

Members Present: All members

Topics Discussed: Roles for PDR, tasks for Friday lab

Objective:

Discuss the roles assigned for writing the PDR.  Discuss what data needs to be collected during Friday lab and how this will be achieved within the limited time of a lab session.

To Do/Action Items:

• Finish PDR
• Collect and plot Arduino data from one successful AEV run with current group design
• Test the performance of each of the two current design options
• Have code written up to a testable point

Reflection:

• Madeleine will write the experimental methodology and assist Lauren with the discussion/results
• Lauren will write the discussion/results with the help of Madeleine  
• Beth will write the executive summary and introduction
• Alejandra will write the conclusion and recommendations along with the appendix
• Alejandra will have written testable code for lab on Friday

Date: 03/24/17

Time: 4:24 PM (face-to-face)

Members Present: All members

Topics Discussed: Performance Tests 1 & 2

Objective:

Discuss plans for completing performance tests 1 & 2 next week.

To Do/Action Items:

• Design schedule to ensure there is enough time to finish what is left of performance test 1 without falling behind on performance test 2 by the end of lab on 03/30.

Reflection:

• Schedule enough time to finish both tests by 03/30 (Thursday) next week.