Group G – Hannah, James, Sydney, and Jeremiah Progress Report Week 6
Instructor – Professor Li 2/9/2019
Week 6
Situation
The main purpose of Lab 1 was to build the use the Arduino given to us at the beginning of the lab and to understand how to work the AEV sketchbook. The sketchbook is a crucial part of the lab since this is where the code for controlling what the AEV will do. The Arduino must be programmed to connect to the right COMP in the computer so that the code written in the sketchbook will be sent to the Arduino for it to execute the code. A program basic exercise of doing a certain code also occurred in lab 1. Using the basic function calls provided in the lab, the code was written out in the sketchbook and sent to the Arduino to be executed. The code was executed to determine how much power was needed.
In lab 2, the main objective was to build the reference AEV and to understand, utilize and test the reflecting sensors. A program that completes the task assigned to us was written in the sketchbook. The propellers spinning in the proper direction, wires being tied away from the propellers, sensors working properly, and teams program working was also completed during the lab. The success of the AEV in completing the scenario using the commands that were in the lab were discussed on certain limits that can occur. The function and the importance in competing that MCR of the reflecting sensors was also discussed.
In lab 3, each group member independently brainstormed an idea of how the AEV should be designed/constructed and drawn on orthographic drawing paper. Once coming together, using each members drawing and the minds of their own, the group brainstormed ideas of how the AEV should be designed and drew the concept sketch (with 3 primary views with overall dimensions, scale, estimated weight, and estimated bill of material with the estimated cost of each). Descriptions of the main features and motivations of everyone’s design was provided as well as why each idea would be successful in completing the scenario.
In lab 4, the main goal was to learn how to use a design analysis tool that provides an efficient and productive method to evaluate the performance of the AEV. After the design analysis tool was properly set up and the sample AEV was build, the assembled AEV was programmed a scenario to be tested on the straight tracks. The AEV was tested on the track and the Arduino data was downloaded after the run. The Arduino data was uploaded into the design analysis tool and a plot of Power vs. Distance and a plot of Power vs. Time was created. The plots were explained by describing what the AEV was doing for each section.
In lab 5, using the different AEV designed from the group members and the team design, the success criteria that fit the AEV design was recorded in a Concept Screening Matrix as well as in a Concept Scoring Matrix. The pros and cons of each design compared to the reference AEV were used to help justify the concept screening and scoring spreadsheets. The two AEV concepts that will be carried forward in the design cycle were also noted clearly.
Results & Analysis
In the first lab, the motor ran well after some adjustments were made. In the first test there was some resistance observed when the motor was directed to run at lower speeds. The motor didn’t have enough power to rotate the propellers, so the power percentage was increased from 15% to 25% to give enough power for a strong start.
In the second lab, after testing the AEV, it was concluded that certain commands need to be well synchronized with others. For example, when the AEV was told to break, it still had enough momentum to continue moving forward. This means that the reverse speed must be synchronized with the brake and initial forward speed to get a proper stopping motion.
In the third lab, each team member made a concept sketch for the AEV and, after considering all of the designs, a final design was chosen. The designs are as follows:
This design was primarily based on minimizing wind resistance via putting all of the parts very close together. By putting all of the parts in-line, and having the only protrusions be the motors, wind would have very little surface area to apply force to. The aerodynamic properties of this AEV design would give it a good speed advantage.
Hannah Design:
This design was drawn with the idea of making the AEV light and try and enhance the AEV to have the least amount of air resistance possible to effect on it. By making the AEV skinny and long, the amount of air resistance hitting the AEV when it goes down the track is minimized since there’s not a lot of area/length for the air to push against the AEV as its moving. As a result the energy efficiency will be higher because less energy will be needed to move the AEV as it would be if there was a great amount of air resistance acting on the AEV.
Sydney Design:
This design was drawn with the idea increasing aerodynamics of the the AEV. The pointed nose will reduce air resistance, along with the length and minimal build. The design is compact and covers all motors and wires. Less surface area will also reduce air resistance. This design also slightly increases the visual appeal of the AEV. Unfortunately this build would also increase the mass of the AEV, and may cause it to be slower.
James Design:
This design was drawn with the thought of the AEV’s weight. For the AEV to effectively complete the tasks it is assigned to do, something that would allow to completion of these tasks to be easier would be making the AEV lightweight. This design is meant to use the smallest and lightest materials at our disposal in order to meet that criteria. This would allow the AEV to move more freely with less resistance on its motors from the weight of the AEV. Another positive that would possibly come out of this design would be the aerodynamics of this AEV which would also decrease the resistance to the AEV even more as it is moving along the track.
Group Design:
This sketch is the final design created by Group G. This AEV was created by taking all the best ideas from each group member and combining it into one AEV. This AEV is not only aerodynamic but also light as it does not have any more components included in it except for the essential tools needed for the AEV to complete the tasks at hand. The simplicity of the design allows this AEV to work the way it needs to and also can be looked at and fixed easily if a road block were to ever occur.
The final Group Design’s bill of materials is as follows:
Table 1: Bill of Materials
In the fourth lab, a code was made for a sample scenario. Using this test scenario, information was gathered about the AEV on a Power Consumption vs Time graph and a Power Consumption vs Distance graph. The graphs and information are as follows:
Table 2: Power Consumption vs Time
In this first graph of Power vs Time, it can be seen how the code affected the power over time. The positive 45 degree angle part of the graph is the acceleration, the two following horizontal lines are the AEV running at 25% and 20% power, the power spike and following horizontal line is the motors switching into reverse, and the long vertical line that leads to 0 Watts is the brake.
Table 3: Power Consumption vs Distance
In this second graph of Power vs Distance, it can be seen how the code affected the power over a distance. The first horizontal line shows the constant power usage during the 25% power section, the second horizontal line shows the 20% power section, the spike and short horizontal line show the reverse sections, and the vertical line that leads to 0 Watts shows the brake.
In the fifth lab, Concept Screening and Concept Scoring spreadsheets were created based on all the AEV designs. Stability, minimal blockage, durability, maintenance, durability, and safety were all rated on each design. These criteria are described as follows:
- Stability – Was the design balanced on the track?
- Minimal Blockage – Was the design was set up in an aerodynamic format?
- Maintenance – How hard it is to access parts like the battery?
- Durability – Were there any physical weaknesses in the structure of the design?
- Safety – How likely is the design to fall or break itself?
Table 4: Concept Screening:
Table 5: Concept Scoring:
Jeremiah’s Design was not stable, but it was very aerodynamic and durable. Hannah’s Design did not do much better than the sample design. Sydney’s Design had poor stability and aerodynamic properties but was very safe. James’ Design had good durability and stability but poor aerodynamics. Finally, the Group Design had good stability and aerodynamics and did just as good as the sample in all other categories. Jeremiah’s Design and the Group Design will be continued to be developed, however, the Group Design will likely be the final design.
Takeaways
When looking at the AEV, one of the main takeaways that our group had was the weight distribution and the general weight of the AEV. One problem we ran into early was that the AEV when hanging on the rails that it was connected too, it would either lean one way or the other when hanging and traveling on the rails. This ended up bothering the team too much so we decided to tear apart the AEV and find a way to make it balanced so that it is centered the whole way going down and back on the track. With achieving the weight distribution, the AEV was free to operate without any resistance from being unbalanced. This greatly improved the efficiency of the AEV as it could be seen that it was easier to move with the weight distributed on its body. Moving forward, the group hopes to be able to keep this trend with the AEV and to keep up the effectiveness of completing all the requirements ahead.
Takeaways concerning the general project learning are that, the group has a basic understanding of what is expected of each member and the work that is needed to be done in order to help the team as a whole. This will allow the team to do the best job possible and to complete the required tasks that are assigned to the team and to the AEV. This also includes knowing what to be working on during the lab and even at times lending a hand when someone may be at a roadblock. The teams time management is also at a great place because each individual team member understands that things should not be left till the last minute to complete. Our team is able to work together in order to get things done on time and with time to spare. This is something important that will be continued moving forward with the AEV project. Another thing that is greatly used among the team is communication. Communication is key within the group as it allows us to be able to know where each team member is with their work and with their understanding of what is going on with the project. It is important that each team member is on the same page as this will allow the project to move smoothly and be completed very well. If not all the team members are on the same page, that leaves room for error and that would require time to fix and bring them up to speed. However this has not been a problem within the team. This is something very important that will be kept moving forward within the team in order to complete every requirement the best we can.
Forwards Looking Plan
Our team will investigate four topics to improve our understanding of the AEV. First we will evaluate the servo motor. The servo motor is an optional, additional piece of equipment, but has a lot of potential to be useful. A servo motor can rotate to the selected angle and maintain its location, while most typical motors will spin continuously. Our Team wants to use the servo motor to brake. Using the servo motor to brake simplifies stopping the AEV and improves the time it takes to do so. We will evaluate which servo position has a bigger advantage and is able to slow the AEV down at the rate we desire. We will either use the arm on the motor to hi the bar itself or the wheel of the AEV. There is a major advantage to the force being applied to the wheel, which is how we plan on executing the servo. Also as a team we will perform testing to find which number of engines best suits our AEV. Having multiple motors may increase the power and the energy efficiency of the AEV depending on our configurations and the number of motors used. The AEV can handle up to three motors. We will come up with at least one motor configuration for each of one, two, and three motor setups. By running tests and collecting data we will be able to determine which motor configuration works best for our AEV.
Our team will evaluate coasting and power braking. We will coordinate testing using these two methods to determine which style suits our AEV and produces more consistent results. Braking is an important component in our AEV completing the MCR,which makes the consistency of braking equally as important. Prepare two codes that will function on the test track, the only difference being whether power braking or coasting is used. We will record forward distance, total distance traveled, and the power used. We will then use all of these components to determine which methods is most suitable for our AEV. Also our team will evaluate different propeller configurations to determine which setup gives our AEV the best combination of speed and efficiency. The orientation of propellers has a serious effect on their efficiency. This will affect how well our AEV performs. To find out the optimal propeller configuration, propellers will be tested in different combinations of pusher and puller configurations, 3030 and 2510 propellers, and any other different configurations. We will evaluate four different configurations and collect data that will determine which configuration is most suitable for our AEV.
Weekly Goals
- Goal for the servo and Evaluate the efficiency of the servo motor. Also perform testing to discover which number of motors best suits our AEV.
- Coordinate testing using coasting and power braking to determine which style suits our AEV and produces more consistent results.
- Evaluate different propeller configurations to determine which setup gives our AEV the best combination of speed and efficiency.
Weekly Schedule
Appendix
- Team meeting notes
- Arduino code
- Additional requirements