Team Vision for Subsystem Level Build & Test Phase

Our team planned to use the subsystem level build and test phase to get both hydraulics operational and finally machine our seat plate. We also plan on welding the final few pieces of our frame so that we can begin benchmark testing against our engineering requirements. 

Getting both hydraulics operational turned out to be a larger task than anticipated. We had to remake both pistons with the help from TA's in the machine shop and one of the switches that controls the flow of water in the hydraulic system broke during testing. Despite the setback, and some of our team getting sprayed with ice cold water, both hydraulics are now working. The seat plate was machined towards the end of this phase using the plasma cutter as the water jet is still under the weather. We will need to sand the aluminum plate because the plasma cutter left rougher edges than the water jet would have, but we finally have it available to start assembling. Jared is working with Cam to have the welding complete by the end of the phase. 

Kimberly, the Industrial Design student working with our team worked with Kaylie to design the handle a handle the user would use to control the hydraulics. Gina and Kaylie used Kimberly's designs to make a CAD model of the handle, and the material to machine it has been bought. Gina, the teams design engineer, has also been working very hard to remedy some issues the team found in previous teams CAD models. 

Build Progress 

During this phase, progress has continued to be made towards completing the build of the device.

Seat plate and Under the Seat Frame

The water jet never came back online for us, however, the plasma cutter down in the machine shop did. Using the new plasma cutter, we were cut out the seat plate. Additionally, during this phase, we welded the under the seat plate components that can be seen in the images below. With these initial framing elements completed, we can start welding the other elements needed for the arm and lever attachments. 


      

Figure 1: (a) shows the completed seat plate and the under the seat plate frame with the toilet seat showing the full assembly.

(b) This image shows the under plate frame by itself. This frame will be bolted to the seat plate. 


Hydraulics

Previously, the hydraulic cylinders had issues where they would get stuck at the bottom position. This was caused by the piston rod not protruding far enough past the piston and not stopping the piston before it obstructs the bottom inlet hole. The reason that this occurred is because the end of the PVC pipe is tapered, meaning that we cannot screw in the brass cap in as far as it was designed too (otherwise we might crack the plastic). To solve this problem, we re-machined the piston rods and extended the portion that extends through the piston. Additionally, a set screw was added into the brass end plug for adjustable spacing. Individual testing of each cylinder was successful, each could move between upper and lower positions without getting stuck.


                                                            

Figure 2: Shows the team individually testing one of the hydraulics. 

Frame

The team seemed to have finished welding together the main frame of the device, however, the crossbar from the previous iteration that was welded to the frame is two inches short of the designed length. This makes it impossible for the seat plate to fit inside the frame. Our proposed solution is to cut the crossbar in the middle and weld additional box tubing and additional inside structural supports to make the frame wider, without removing welds and potentially damaging our materials. This issue highlights how the tolerances of this design are restrictive of the range of toilets this device can fit to. A future solution could implement telescoping parts on the frame. Telescoping parts on the frame would allow the device to adjust and fit to many different toilets. 

Additionally, previously manufactured support parts were not bent correctly, so they do not line up properly and were impossible to weld as designed. The frame is sturdy without these parts and the the two legs were not able to flex, so we decided to leave this supports off the frame for now and will re-machine them correctly if needed in the future. 

                                                                                            

Figure 3: (a) This image shows the current frame without the crossbar adjustment. (b) This second image shows the support plate for the frame that was machined incorrectly by last years team. 

New Hydraulic Valve

During testing of one of the hydraulics, one of the T-junction broke, and sprayed water everywhere including at team members. In order to continue testing of the hydraulics and eventually test both hydraulics in unison, a new hydraulic valve was purchased. A 4 way 3 position valve was purchased to simplify hose management. The valve eliminates the need for T-junctions on the water inlet and return lines and allows for the a single lever to be used to move the seat up or down. 

                                                                                                                   

Figure 4: Image of the new hydraulic valve. 

Hydraulic Lever Redesign

The lever attached to the hydraulic system left over from last year left a lot to be desired. It was small, finicky, and thin, as such we decided a redesign was necessary. Kaylie worked with Kimberly to come up with a design concept for a lever that could be used easier. The new valve mentioned above comes with a much better lever. We decided as a team to still move forward with the design of a new lever intending to still replace it with a custom lever that is easier to grab onto. The new lever design would allow for easier control of the device even with lower finger dexterity and strength, as it includes a longer "grip" area. This change would allow for the lever to be moved simply by pushing with the palm of your hand rather than requiring the user to grab onto the end.

                                                                                                                    

Figure 5: CAD image of the redesigned lever

Once the team decided to order a new valve we were able to utilize the diagrams provided by the manufacturer to ensure that the new lever would be able to fit into the existing lever's location. The valve we ordered already allowed for the movement of the lever between two orientations and is ripe for replacing with a custom handle as we see fit.  


Other progress completed during current phase

During this phase, the team also has begun work on planning and scripting our draft imagine RIT video.  Additionally, the team noticed some issues with the bearing that are used to slide the seat plate up and down the frame, the previous team did not account for the diameter of the bearing and so some of the bearings do not actually make contact with the guide rail. However, the team believes they are able to fix the issues when securing them in place. 

Bill of Materials

                                                                      

Figure 6: Updated Bill of Materials, as of 2/27/2021

During this phase, we purchased three products/parts for our design and one replacement part. We replaced the original valve when it broke early on during this phase, but now have decided it is no longer needed. A stainless round bar was purchased to re-design the lever of the hydraulic valve. We made our largest purchase yet this phase and bought a 4 way 3 position valve. This will be used to control the water flow from inlet and exit ports on each hydraulic. Lastly we bought brass barbed fittings to connect the hoses to the valve. We are still within our budget with $216 remaining. The live Bill of materials and last years parts can be found here.

Risk and Problem Tracking

During this phase our risk and problem tracking document were updated. For the problem tracking document several problems that occurred during the build progress were added to the document. Some of the problems that were added included the issues with the hydraulic pistons and well as the solution and the successful implementation of the the hydraulic piston rod into both hydraulics. Additionally, the discovered issue with the frame was added and the potential solution that was generated from brainstorming with the team as well as Cam. The risk document has been updated as well. Some of the risks related to machining of the new parts were closed since the new parts that need to be fabricated have finished being machined. The risks related to the hydraulics working independently of each other have also been closed. New risks of the hydraulics not working in unison or rising to different heights and/or at different speeds have been added to our document. The updated links to these documents can be found below. 

Plans for next Phase

By the end of the next phase, the team plans to have the hydraulics and main frame fully assembled into the prototype so our test plans can be executed. The arms and torso support should also be fully designed and either be in the process of being machined or are have finished being machined. The team looks to have the main elements of the device assembled by end of the next phase, to make sure time is available to make adjustments to the design to make it more aesthetically pleasing or more approachable to the end user. 

Additionally by the end of next phase, the Imagine RIT video should be completed and 75% of the technical paper should be completed. This will allow us time to work on the updated video, and make sure the rest of the documentation is up to date before the customer handoff at the end of the semester. 


Individual Three Week Plans

Functional Demo Materials

Include links to:

  • Aucune étiquette