During the final phase of MSD I, team Climate ConStroller worked to finalize their design ideas so they can begin building at the beginning of the next semester. Throughout this phase, the electrical designs and the ventilation system design were completed. It was also discussed where components would be added to the stroller. The BOM was also revised and the team began to order materials.
Team Vision for Detailed Design Phase
Progress ReportBefore Thanksgiving break, our team was responsible for writing a progress report for our customer and guide to update them on our project status.
The team's progress reports are posted here.
Prototyping, Engineering Analysis, Simulation
Plastic Cover Prototyping
The front and sides of the stroller were covered with Saran Wrap to simulate the plastic cover that will eventually be attached. This prototyping assisted us in determining some questions that will need to be answered in the next phase such as:
- Where are the possible locations that the plastic can be attached to the stroller?
- Is there a need for more than one attachment point (does there need to be a zipper at the tray or can the plastic just rest on the tray?)
- If the plastic is tight near the foot tray, will that pose a problem if the child kicks the plastic, and will it decrease the amount of foot room for the child?
- Does the back, top and side holes need to be covered with plastic?
- Does the amount of plastic attached and location affect the weight and/or ability for the stroller to be collapsed?
A ventilation system analysis was done using Matlab to answer the following questions:
- What volumetric flow rate would we need to supply fresh air to the child and remove stale air?
- How much time will the system take to lose heat?
In an attempt to better understand the system and learn how to evaluate the given parameters, students modeled a solution to the layout of a simple, forced convection ventilation system. Flow path was mapped out logically according to increasing temperature and pressure.
Maura met with Robert Hudson, RIT alum and ASHRAE engineer, to better understand ventilation design.
Subject Matter Expert Meeting: Robert Hudson (11/29/2017)
Students developed Matlab code to analyze system over varying parameters.
Revision 0: Matlab Document
The system was modeled without a forced ventilation system, this model did not account for the heat given off by the child. The model simply accounting for infiltration from the nylon of the seat and low density polyethylene from the cover. Resulting in a volumetric flow rate of approximately 2.5-3 [in^3/min]. This would require about 13-17 [W] of power to accomplish.
Following the same system model, the stroller was analyzed to see how long the system would take to reach equilibrium with the outside air temperature. The model looked at the stroller as still being sealed with the heater on. The system would take approximate 82 days to fully lose heat from 74 [deg F] to -40 [deg F].
Drawings, Schematics, Flow Charts, Simulations
Electrical System Schematic
Software FlowchartUsing the inputs and outputs of the electrical system a preliminary software flowchart was created for the stroller. It uses a series of logic statements to determine what should be done about the internal temperature of the stroller.
Location of Components on StrollerThe location of each of the components of the heating system have been mapped out in the images below. These are preliminary locations and are subject to change.
Bill of Material (BOM)BOM With the continuous changes being made to our system, our BOM was updated as needed. The revised version of the BOM is linked here.
Budget Pie Charts
The test plan was updated and finalized from the previous phase in preparation for MSD II. Each test plan is outlined individually and maps back to an engineering requirement specified in the first phase.
|Individual Test Plans|
- The following risks will be mitigated through testing in MSD 2.
Plans for next phase
- As a team, what do you need to accomplish between now and the end of the semester?
- -Take the feedback from the Detailed Design Review and make any necessary changes or improvements
- -Have our team gate review to discuss the work done throughout the semester and discuss how we will start MSD II
- As a team, what do you need to do to prepare for MSD II?
- -Maura will continue to research the ventilation system to ensure it is correct
- -Prince will continue to order the materials we have finalized
- -The team will take a mental break from the project to return energized and ready to work at the start of MSD II
- The team's individual three week plans are located here.