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Team Vision for Detailed Design Phase
The team accomplished a lot during this final phase of MSD II and we were able to check off more tasks and items that were present on the Jamboard and Gantt chart as completed. However, during this phase, RIT changed to Level Orange for their covid alert, which led to some changes that led to some setbacks. The team planned to finish assembling last years prototype, however, the move to level orange, led to the mechanical engineering technology labs, that Jared and Cam where using to weld the seat frame, to close. Since the framing under the seat is needed to complete the prototype, the team was unable to complete the task at this time and the tasks was carried over onto next semester's schedule to be completed early on during MSD II. However, all the materials, like screws, that were required to finish assembling the prototype have all been purchased and received at this time. Additionally, with the raising alert level, the team decided we would feel more comfortable meeting over zoom opposed to in person, so the next set of hydraulic testings was moved in the schedule over to next semester as well. Even though, the team experienced some setback, by planning ahead and also being further along in the project then some other teams, the team remained in a good place throughout the phase. The team shifted their focus to the changes to the CAD modeling. The team brainstormed and then implemented changes into the CAD model, based on each team members input. Additionally, the team was able to create all the needed test plans. The engineering requirements were categorized into requirements that were similar or have similar testing procedures, and the each grouping of requirements were assigned to specific team members. Furthermore, Kaylie was finally able to get in contact with a lab instructor, to complete the materials testing, so the material testing should be good to go starting in the beginning of next semester. The team has also gotten started with the human-subject testing certification process, so during next phase, if in-person study participation is allowed again, the team is able to have a participant test the device for feedback and assess the usability/functionality of the device. During this phase, a preliminary schedule for MSD II was created, based on the phase review dates, the Imagine RIT event, and carrying over tasks from this semester that were not completed or still in progress. The list of task accomplished during this phase and those planned but not completed are shown below.
Planned Tasks That Were Moved to Next Semester:
Welding of the framing under the seat plate
Hydraulic Testing
Biocompatibility/Chemical Testing
Accomplished Tasks For This Phase:
Purchasing final materials needed for Assembly of last years prototype
Finalized changes to CAD model for hydraulic system mounts and armrest attachment location
Test Plans
Human Subject Testing Training- should be completed before the start of break
Found Case Studies on the bacterial adhesion to our chosen materials
Confirmation of lab access for material testing
Preliminary semester schedule is set for next semester
Prototyping, Engineering Analysis, Simulation
Over these past two phases we have spent a decent amount of time looking into our inherited design. We have found a decent amount of quirks that just do not make sense to us, and we either need or want to redesign. The first thing we took exception to was how the hydraulics were mounted to the seat plate and framing. Last year's connection is shown below.
Figure. 01: P20011 Hydraulic / Seat Plate Connection
We are not the biggest fan of the use of the tubes for mounting, as it seems rather flimsy. We also decided due to the materials leftover and put together that we would do a mashup of the bottom mounting from P20011 and the top mounting from P19011.
Figure 02: P19011's Top Hydraulic Mounting
In order to adapt the mounting the way we want, we decided to replace the rods with box tubing. We feel this would allow for more stability while also allowing for an easier assembly process. Due largely in part to a temporary lack of access to our materials due to COVID and our decision to go online for the remainder of the semester, we have not currently identified what they are using to connect the hydraulic to their seat plate. It appears from pictures to be a sort of eye bolt with a ball bearing but the sizing and types are not included in their Bill of Materials. We have adjusted the CAD model to account for our changes, leaving off the connections for now.
Figure 03: Current CAD redesign without connection piece added
There are still more things to work on in relation to this connection, but we feel as though we are in a good space moving forward into next semester.
Bill of Material (BOM)
The Bill of materials includes the main materials need to manufacture the majority of our prototype. Our locker was just about full of materials from last years design when we started this project. We decided to work off their design by documenting all the materials in our locker to see what was missing or what needed improving. After compiling all the parts and raw materials on hand, the total estimate is around $351.34. The previous group also provided us with a breakdown and calculation of raw material needed for tubing, hardware, bar stock, and seat plate materials. Figure 04 shows the material list currently in our locker along with a total price estimate.
Figure 04: Current Material List in Locker
Given the amount of materials in our locker, our goal has been to continue working though the current design components and changing them where we see fit. One change we are making is the seat plate hydraulic connection. New hardware parts will be ordered next phase to accommodate our design change. Below in is our current bill of materials showing the two hardware components we purchased this phase. With the previous years parts at hard, our team does not plan on requesting an additional $500 for the completion of the project. The live Bill of Materials document can be viewed here.
Figure 05: Bill of Materials
Test Plans
Our team developed twelve different test plans to cover all 30 of the engineering requirements. The test plans are listed below:
- Seat and Armrest Weight Capacity
- Seat vertical Range of motion
- ADA Dimensional Requirements
- Hydraulic System Velocity and Acceleration
- Hydraulic System Min and Max operable Pressures
- Sharp edges, Pinch and Pressure Points
- Comfort and Visual Appeal
- Overall Device Stability
- Torso Support bar functionality
- Biocompatibility
- Bacteria Growth Rate
- Bacteria Adhesion Rate
- Chemical Compatibility
- User Operation
Each test plan test plan details the specifications being tested, equipment required, data collection strategy, and the process flow during testing.
Each specification is broken down into the following components:
- Importance
- Source of specification
- Function
- Specification metric
- Unit of measure
- Marginal Value
- Ideal Value
The equipment required is driven by the specification metric and the marginal and ideal values to adequately measure the specification metric.
The data collection strategies detail the implementation of the testing equipment with the device to report meaningful data.
Each test plan has a testing flow chart that details the sequence of events during the test.
Risk Assessment
During this phase, no new risks have been added to the risk assessment. However, most design-related risks have decreased in likelihood or severity, but most of our covid-related risks have increased in likelihood as the on-campus prevalence of the virus and in the county have increased.
The updated risk assessment is found here.
Progress Report
Over the course of the semester, the team completed many tasks in order to make progress towards completing a final working prototype by the conclusion of MSD II. Some of the work completed is listed below:
- Use Cases
- Benchmarking
- Customer Requirements
- Engineering Requirements
- Functional Decomposition
- Concept Generation
- Selected System Level Design using Pugh Chart
- Risk Analysis
- Systems Architecture
- Bill of Materials
- Feasibility Analysis
- Flow Charts
- Began Assembling Prototype
- Made Changes to CAD Drawing
The teams jamboard and gantt chart linked below, shows some of the tasks and action items that each of the members of team needed to complete over the course of the semester. The jamboard and Gantt Chart was mainly for tasks spanning more than an hour and were more often completed outside of class time so still more quicker, in class tasks were completed throughout the semester, than what is just reflected on both charts. For examples, researching hydraulics was added to the jamboards but quick tasks including purchasing the screws we realized we didn't have while trying to assemble the device was not added to the jamboard.
Although, there are some tasks that were not completed due to the covid level moving from oranges, the tasks are already moved into next semester's schedule. And the team feels that we are ending in the semester in good place based on our current progress this semester.
Plans for next phase
The team will follow all safety measures possible over break and return to campus, complying with all RIT implemented COVID-19 guidelines. Safety of the team is of the utmost importance to all 5 team members, and as the next semester details progress the team will discuss the best course of action in terms of in-person vs zoom meetings. Following RIT policy, all team members will be COVID-19 tested and must test negative prior to meeting in person on campus at the beginning of MSD II.
We have discussed, and will continue to discuss, what changes we need to make for testing plans if we are moved fully virtual next semester.
Will they or won’t they??? The water jets in the Mechanical Lab are unpredictable, and other avenues will need to be explored to manufacture the rest of our prototypes components if it does not work next semester.
The team plans on looking into purchasing options for attachable bidets, based off of feedback throughout the first semester. Those plans will begin once we get back and we will update during the first review of MSD II.
Individual Three Week Plans:
Design Review Materials
Include links to: