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Team Vision for Integrated System Build & Test Phase
Our team's goal for this phase was to finish assembling the final prototype. We wanted to get all of our welding completed by the end of the phase and correct some imperfections found in previous iterations CAD models.
Thanks to Cam, Jared, Chad, and the KGCOE Mech Shop staff, we were able to complete almost all welding that needed to be done to fully assemble the prototype. During this phase we created and manufactured the parts needed to assemble the bearing guides. Additionally, we fixed the framed by welding an additional segment in the cross-bar and we decided on the valve placement and how we are attaching the top of the hydraulics to the frame. With the valve placement decided, we drilled the holes in the seat plate and the flow path of the valve needed to be adjusted from the side to the top of the valve. Furthermore, we ordered and replaced the O-rings in the hydraulics to ensure they would be in the best possible condition.
This phase we finally took team photos that we were able to incorporate into our lightning talk video. The team wrote and recorded all of the voice over audio and Hannah compiled it into a complete 2 minute video. We registered as an event for Imagine RIT before the deadline so we are all set to ‘exhibit’. We achieved 75% of our technical paper complete and are working on preliminary designs of our team poster. The team has decided on the final arm design and are close to completing the assembly and we are having discussions on the possible changes that could be made to the angle of the legs.
The team also had the opportunity to visit the livability lab during this phase. The team received keys to the lab and are try to move the device over to test in this facility by the end of the semester.
Build Progress
Widening the Frame
Previously the wrong bar was welded as the cross bar for the frame, to fix this mistake, a 2 inch segment was welded to the frame with supportive structures on the inside. This was completed by Jared and Cam and no instability was noticed in the frame due to this additional weld.
Figure 1: Image of Segment Welded to Frame of the Crossbar
Bearing Guides
To get the bearing guides in place, the bearing guide attachment fixture needed to be welded to the seat plate, once that was complete, the bearing guides, with the bearing guide spacers were assembled onto the frame.
Figure 2: (left) seat plate with bearing guide attachment (right) assembled bearing guides with spacers
After assembling the bearing guides, the team noticed that the bearings do not properly align with the frame of the device. This is due to the holes drilled on the bearing guides, being done of the waterjet. The tolerances of the waterjet were not properly considered and this causes the seat plate to tilt forward when weight is applied. To fix this the team plans to at a steel plate against the frame to prevent this movement of the bearing guides.
Lever Placement, Seat Plate and Bearing Guide Attachment
After all the welding was completed for the seat, the lever position was determined on the seat plate and the holes were drilled to connect the final frame pieces together. Holes were drilled into each of the components and attached with screws.
Hydraulic Mounting
To attach the hydraulics to the frame, bars were welded to the seat plate and then the mounting brackets were attached to the frame. This allowed for the hydraulics to be attached to the seat plate frame.
Figure 3: (left) hydraulic attachment (right) assembled device
Arm Design
The team decided to make several changes to the arm design from last years. The team decided to raise the height of the arms to increase the support offered. Another change that we made was we decided to keep the arm shaft the same, however, instead of using pins to the lock the arm in place, the team designed a mating piece that can fit into the spaces in the shaft to lock the arm in place. The mating piece will be fixed to the arm bar and will rotate the arm with it. This design option gives user, 8 positions they can utilize during transfer and for support while using the device in a position that is most comfortable for them. Since this design eliminates any small pieces that could be dropped or lost, like the pin, this design was determined to be the better option.
Figure 4: CAD models for the individual components of the the arm attachments
Figure 5: CAD model of the newly designed arm
Testing Results
During this phase since we completed the assembly of the device other than the arms, we started system testing of the device. After assembly and initial dry-run testing of the system, the pressure needed to overcome the O-rings friction were too great, as a result we removed one O-ring from each hydraulic to decrease the friction. The result allowed for smoother lifting of the device. After this initial testing, the team began executing the test developed during earlier phases of the project. The list of the test plans executed and the results are listed below.
The list of customer and engineering requirements that are related to each test plan are summarized in the document here.
The data and results of each test plan executed can be found in the document here.
User Operation of Lever
The device does respond to lever movements for several cycles.
This satisfies requirement S28.
Hydraulic System Velocity and Acceleration
The maximum velocity and acceleration of the device do not exceed the engineering specification listed for the device. During testing the device did not stop or get stuck while either raising or lowering.
Successful completion of this test satisfies requirements S9, S10, and S11.
Seat Height Max and Min
The maximum seat height requirement for the device is met during testing. However, the minimum height of the toilet does not satisfy the current requirement (min height of 17 inches) this is because the hydraulic cylinders and mounting structures exceed this min height value. Since the hydraulic will need to be redesign to allow for a wider weight capacity of the device, we recommend the hydraulic cylinder are shorter and have a larger diameters which allow for the device to meet this minimum height restriction.
The testing shows the successful completion of S2, however S3 is not met with this current design.
Weight Capacity
The execution of this test plan has been started, however more weights are needed to be added to the device. The weight capacity of the arms also needs to be tested, so the team needs to wait until they are fully assembled onto the device to complete this test plan.
Bill of Materials
Figure 6: Updated Bill of Materials, as of 4/11/2021
During this phase, we purchased four products/parts for our design. Flow control valve was purchased to manage the water flow from the inlet. We replaced the original hose fitting that connects to the water source, but it still seems to leak. We purchased more O-rings to replace the current ones inside the hydraulic. Lastly, we purchased flex seal to add finishing touches to possible leak areas. We are still within our budget with $140.89 remaining. The live Bill of materials and last years parts can be found here.
Risk and Problem Tracking
We had several additions to the risk document this phase. For the hydraulics system to control leaking, flex seal was purchased to minimize some of the leaking that is coming from the bottom of the hydraulics. The leaking is due to lack of cap at the bottom not properly screwing all the way in. The risk for the hydraulics operating at different heights was reduced in severity due to primarily testing showing the device leveling out during operation. Three new risks were added to the risks document, 36, 37, and 38. The one deals with the O-rings needed to replaced due to them ripping when we assemble and disassemble them. The other deals with the operation of the device during testing. The final risk added dealt with the problems discussed with the arm and torso bars, however, the arm design has been completed. Once the team makes a decision for the torso bar then the team anticipates this risk will be closed.
The link to the updated risk document is here.
Figure 7: Updated Risk Document
Additionally, during this phase the problem tracking document was updated. From last phase, we were able to implement the solution to fix the crossbar and it proved to be successful. No additional measures are needed to fix any problems. Another problem that was added to our document was that the arm and torso bars were not feasible as they were designed by last years team. Last years design required the user to move a pin and place it into a hole on the arms to lock it in place. We however were concern to have this solution if the user has limited dexterity. So, the team redesigned the arm shown above to fix this problem. This the implemented solution was added to the problem tracking document and the solution will be evaluated once the parts are finished being manufactured. A second risk that was added to the document concerned that hydraulic would get stuck while rising and lowering. The team believed this to be due to the friction caused by the O-rings. One O-ring was removed from each hydraulic and the device raised and lower more smoothly.
The link to the updated risk document is here.
Figure 8: Updated Problem Tracking Document
Functional Demo Materials
Include links to:
- Pre-read
- Presentation and/or handouts
- Notes from review
- Action Items
Plans for next phase
For our final phase, the teams goal is to have our functioning device fully painted and assembled. The goal is to have the device set up within a restroom facility at the Livability Lab in preparations for Imagine RIT. The team will work to complete all needed documentation before the customer hand-off at the end of the semester. Documentation to be include, results of test plan, manufacturing instructions, as well and future steps.
Additionally, the team is looking to have the technical paper and poster completed within the next couple weeks to allow ample time to wrap up the remaining of the agenda items for the semester.