P18046: The Overcomer
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Preliminary Detailed Design

Table of Contents

Team Vision for Preliminary Detailed Design Phase

Our goals for the first half of the detailed design phase centered around finalizing system and subsystem design concepts, generating 3D renderings of those concepts, translating engineering requirements into future test plans, performing feasibility analysis on our concepts, and beginning to consider material selection for our subsystems.

Finalized Objective Statement

Our objective is to design a product that enables disabled individuals to enjoy trapping / kicking a ball.

Updated Systems Architecture

The working systems architecture depicts the mass, information, and energy flows of the system. The diagram displayed below represents the current design the team is working on however in the link you will find a different artchitecture representing an alternate design the team came up with.

A link to the working Systems Architecture flow diagram as well as additional description and design alternative architectures can be found here.

Systems Architecture

Systems Architecture

Feasibility: Prototyping, Analysis, Simulation

Proposed Frame

Proposed Frame

Adjustability

Adjustability

Incorporating Upper Extremity & Lower Extremity

Incorporating Upper Extremity & Lower Extremity

Attachments

Attachments

Calculating & Implementing

Calculating & Implementing

Comparison

Comparison

Applied Lever Force Feasibility

Applied Lever Force Feasibility

Inputs and Source

  1. Engineering Requirements
  2. Concept Selection
  3. Results of preliminary prototyping, analysis, and simulation

Outputs and Destination

  1. A list of Design Parameters, Quantified Targets, and acceptable tolerances
  2. Sensitivity analysis
  3. Refined concept Selection
  4. Drawings, Schematics, Flow Charts, etc.

Drawings, Schematics, Flow Charts, Simulations,Feasibility

User Interface Modeling

The user interface was CAD modeling in SolidWorks 2017. The primary plan is to make modifications to a road bicycle shifting mechanism because of its compact indexing nature to close the arms and preload the launching mechanism.

public/shifter1.jpg public/shifter2.jpg

The following is a contingency plan and the SolidWorks model of the user interface if the usage of the bike shifting mechanism becomes unfeasible. The system works similar to a bicycle shifter, utilizing an indexing ratcheting gear with a quick release mechanism. In addition to the model shown, small modifications will be made to attach a cable to the ratcheting wheel, and ergonomic levers to the device for preload and launch.

public/render.jpg

The cable will then be split using a cable tripler to attach to the arms and launcher assembly shown in the following section. Shown below is an example of a cable doubler which will be modified to accommodate splitting into three cables instead of two.

public/splitter.jpg

Catch and Launch Modeling

The Catch and Launch system was CAD modeled in SolidWorks 2017. The system contains many parts included a base, arms, pins, launcher, and a spacer.

The base, arm, and launcher in the un-launched position, respectively.

Base Arms |Launcher (in unlaunched position)

The whole system assembled in the open and ready to catch position can be seen below:

public/Open 2.png

The whole system in the closed position, with a ball caught and ready to launch can be seen below:

public/Closed 1.png public/Closed 2.png

The whole system in the process of launch was mocked up in SolidWorks and can be seen below.

public/Launch 1.png public/Launch 2.png

Each element is at a different height to avoid accidental collisions. This allows the arms to overlap in catching and the launcher to travel over the arms. This height distribution can be seen below:

public/Open 1.png

The working SolidWorks 2017 files can be downloaded here.

Feasibility

As part of the development of these models we ran calculations to determine rough values we would need to have for the catch and launch system. Below is a quick graph of our input values, developed from our engineering requirements and design development and the corresponding values that we got out of those inputs.

User Interface Feasibility

User Interface Feasibility

live document.


Timing Diagram

To better understand the functionality of the device, a functional system timing diagram was developed based on the key subsystems of the design. The diagram incorporates rough approximations of time taken to accomplish the high level functions required of the device. The diagram is investigating the timing taken by the cantilever arm design specifically.

A link to the working Timing Diagram can be found here.

Timing Diagram

Timing Diagram

Bill of Material (BOM)

A preliminary BOM was constructed in order to begin accounting for expenses and determine whether we will be able to deliver our product within our allowed budget. This activity caused us to rethink some of the choice of parts and materials that we had previously picked.

Our live preliminary BOM can be viewed in Google Sheets. A preview is shown below. Exact quantities and costs have not been finalized thus far in the design phase.

Preliminary BOM

Preliminary BOM

Input and Source

  1. PRP
  2. Design Files.

Output and Destination

Completed BOM and Budget

Test Plans

Purpose

Our test plans are at a preliminary stage at this point, and will continue to be updated as the design is finalized. The image below is a snapshot of our current User Testing plans. These were designed based on our use cases and engineering requirements, focusing on the aspects of the device that are most important to the end user. In the future, we will add test plans for specific subsystems, which will be populated to the Detailed Design page.
User Test Plans

User Test Plans

A link to the live-updated version of our test plans can be found here.

Inputs and Source

  1. Engineering Requirements

Outputs and Destination

  1. IRB Submission, if applicable (allow at least 30 days for this to be reviewed - more time is idea, since the IRB outcome may be a request for you to modify your proposed test protocol)

Risk Assessment

The risk analysis was updated from last cycle and a link to the working risk assessment document can be found here. The risks are categorized and ranked based on a product of their probability of occurence and severity if they were to occur. The scaling is a 1-3-9 system where 9 is most important and 1 is least important.

Updated Risk Assessment

Updated Risk Assessment

Design Review Materials

Our PDDR Slides were created on Google Slides and presented on Thursday, November 16th at 12:30 in GLE-4425.

public/PDDR Screenshot.png public/PDDR Agenda.png

Plans for next phase

At the end of phase 3, our team reflected on our work so far for the current phase. We went back to our Individual Plans for Cycle 3 and compared our predictions to what we actually worked on during phase 3. We also reflected on some of the things we learned during the Preliminary Detailed Design phase.

Then, to be better prepared for the next phase, our team took a look at the upcoming deliverables due for the next phase. We came up with task lists for the individual work that we would complete to contribute to our Phase 4 Design Review. The Individual Plans for Cycle 4 were created as a Google doc and will be updated after the completion of Phase 4 with what we actually did and learned during Phase 4.

In terms of overall project planning, the next phase will primarily be focused on improving and adding final details to our design so far. In addition conducting more complex prototyping, we will make final decisions about materials and components, and begin to identify suppliers to order from. These changes will be updated to our Bill of Materials (BOM). We will also finish test plans, to be used in MSD II while we build the prototype. As always, we will continuously update risk management.

Our team is continuing to use Trello to track and assign individual task information. Our Trello board can be viewed here.


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