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Team Vision for Problem Definition Phase
Because our team is tasked with completing a previous team's design, we planned to examine our project in terms of the current state of the design and what new challenges we may face during this term. We planned to compile an updated list of engineering and customer requirements, and use those to guide our design research.
Our team analyzed the previous team’s work and the current state of the project. We met with our customer, Marcos Esterman, and talked about the major customer requirements regarding this system. We then made a list of corresponding engineering requirements, and identified our major design drivers and design issues. Our team benchmarked suitable power subsystems to extract ideas and relevant information that could be applied to our future project plans. We also established team roles and assigned preliminary tasks for each team member.
Project Summary
Power grids in locations such as Columbia are often unstable which results in unreliable power sources. Battery-grid hybrid systems can be used to alleviate the power instability of a region, often using renewable sources to charge the battery. A mobile power station could provide support for a variety of applications that require uninterrupted electricity. In 2017, a cart with solar panels was developed to provide a dependable power supply for a 3-D printer. In 2019, the power system for the 3-D printer became its own system, designed from the ground up. The initial design of this system included a custom cart for switching between power sources, increased ease of use and assembly, and the ability to fail gracefully without power. Due to the COVID-19 pandemic, work on the 2019 version of the cart was not completed.
The goal of this project is to enhance the progress made during the 2019 academic year. Two additional power sources are to be included to supplement the solar power, while also being cognizant of limited supplies and resources in the area. The cart must be capable of withstanding the effects of transport and environmental abuse. The expected result is a functioning prototype cart with instructions for assembly, disassembly, testing, and regular use.
Use Cases
Battery Powered:
The grid is not on and the battery is dead. The Spark Cart will indicate to the user to plug in an alternative energy source to charge the battery. Once the alternative source is attached and the battery has enough power, the cart will indicate adequate power. The application will turn on and the battery will run the appliance.
Battery Powered:
The grid is not on and the battery is charged. The cart will indicate to the user to attach an alternative energy source. While doing so, the battery will charge and run the appliance; however, the appliance uses more energy than the alternative source generates and the battery becomes depleted. The cart will indicate so and the appliance will fail gracefully.
Grid/Battery Powered:
The grid is on and powers the appliance. Option 1: the grid turns off but the battery is fully charged. The cart indicates to the user to attach the alternative power source while still running the appliance. The battery remains powered enough to complete the application. Option 2: the grid stays on and the appliance completes the application.
Grid/Battery Powered:
The grid is on and powers the appliance. The grid turns off but the battery is fully charged. The cart indicates to the user to attach the alternative power source while still running the appliance. However, the appliance uses more energy than the alternative source generates and the battery depletes before the appliance is finished. The cart indicates not enough power and the appliance fails gracefully.
Project Goals and Key Deliverables
Expected end result of the project, what the customer can expect to receive at the end of the project.
Customer Requirements (Needs)
Project Name | P21462 |
|---|---|
| Team Name | Solar Powered, Portable 3D Power Cart v2 |
| Document Owner | Jacob Wildt |
| Date | 9/4/2020 |
Customer Requirement | Ranking |
AC output | 9 |
Can take unanticipated load | 9 |
Easy to transport via airplane (meets size restrictions) | 9 |
Easy to transport via car (fits in mid-sized car) | 9 |
Has two more sources than solar & grid power | 9 |
Easy to assemble and disassemble for multiple types of transport | 9 |
Fails gracefully | 9 |
Switches sources seamlessly | 9 |
Reliable (electrical and mechanical) | 3 |
Lightweight | 3 |
Collapsible | 3 |
Durable for transit | 3 |
Low cost | 3 |
Display power statistics | 3 |
Room for upgrades | 3 |
Durable in weather | 1 |
Mobile without vehicle | 1 |
Multiple power outlets | 1 |
Make commercialization possible | 1 |
Engineering Requirements (Metrics & Specifications)
Project Name | P21462 |
|---|---|
| Team Name | Solar Powered, Portable 3D Power Cart v2 |
| Document Owner | Jacob Wildt |
| Date | 9/4/2020 |
Engineering Requirement | Measure | Target Value | Acceptable Value |
Able to move on incline without tipping (x-axis) | Tilt in degrees | ||
Able to move on incline without tipping (y-axis) | Tilt in degrees | ||
Able to move across varied terrain gradients | Test pull force on grass, dirt, gravel, and pavement | ||
Able to seamlessly switch between sources | Yes/No | ||
Durable while in packaging | No damage to parts after transportation simulation | ||
Durable while freestanding | Cart stays assembled when unattended for a period of time | ||
Quick assembly/ disassembly from packaging | Timed assembly/disassembly | ||
Quick assembly/ disassembly from car transport configuration | Timed assembly/disassembly | ||
Light enough to carry | Weigh cart by sections it comes apart into | ||
Compact | Dimensions of cart when collapsed for car travel | ||
Outputs enough power | Wattage measurement | ||
Complies with safety standards | OSHA and UL standards | ||
Weatherproof | IP rating testing | ||
Low development cost | Fixed budget | ||
Motionless tilt stability (x-axis) | Tilt in degrees | ||
Motionless tilt stability (y-axis) | Tilt in degrees | ||
Smart shutoff | Oscilloscope observation | ||
Able to support physical load | Weight loading | ||
Modular, replaceable parts | Components can be replaced in a small amount of time | ||
Design for manufacture | Cart can be produced using Colombian fabrication processes (Yes/No) | ||
Locally sourced parts | Parts can be acquired in Colombia | ||
Two additional power sources | Number of sources contributing to battery charge | ||
USB Connections | Yes/No |
Constraints
- Must switch sources seamlessly
- Must have two power sources beyond solar and grid
- Must fail gracefully
- Must be transported for shipping and by car easily
- Must be easy to assemble and disassemble
- Must output enough AC power to power more devices than anticipated
House of Quality
Project Name | P21462 |
|---|---|
| Team Name | Solar Powered, Portable 3D Power Cart v2 |
| Document Owner | Jacob Wildt |
| Date | 9/4/2020 |
Design Review Materials
Plans for next phase
Team plan
In the next phase, we will define the functions that our system has to perform and generate concept designs that will be able to perform these functions. Once we have concepts to compare, we will define the key metrics that will be used to choose a concept to move forward with. After a concept is chosen, we will define the exact inputs and outputs that each of the subsystems will need to facilitate the beginning of our detail design. At the end of the system level design phase we will re-evaluate the risks that our project faces and adjust our plans accordingly.
Individual Plans