Integrated System Build & Test
Table of Contents
Team Vision for Integrated System Build & Test PhaseWhat did we plan to accomplish:
- Purchase/Recieve all remaining materials
- Cut frame and seat
- Assemble frame and seat
- Test frame and seat
- Decide on interface for cylinders to frame
- Assemble hydraulic system
What we accomplished: We accomplished everything except for receiving all materials. The peg assembly for the armrests and the seat cover have been ordered, but have not arrived.
Design FeedbackWe met with Chris after the frame and seat was assembled to get design feedback. Some of his suggestions for things to look out for are:
- Making some adjustments to the knob so it's easier to grab.
- Being careful where we put the knob so it doesn't get in the way.
- Make sure that the knob placed over the nut is sturdy and durable and users clothes won't get stuck on it.
- Making the design look less "industrial"
Attached are the full notes for Chris's Feedback.
Fabrication & Assembly
The hydraulic cylinders were pinned into brackets which were welded to the frame. The Hydraulic setup (valve and flow divider) was rigged to an apparatus for testing purposes.
Test Results Summary
The lifting assembly was completed just recently, meaning the testing must be done from here out. Refer to the updated plan for test schedules.
Static/Dynamic Load TestingPrior to installing the hydraulic system, a static load test was performed and it was deemed that the seat met our specifications. Below is a picture of the test. A video of the initial testing can be viewed here.
After the hydraulics system was installed, a preliminary load test was performed. With the testing done thus far, it appears that our design meets our specifications. Some further testing will need to be complete to verify this. Below is an image of the dynamic load testing.
A more thorough load test was performed and the data is listed in the table below. For different weights, we tested how long it took the seat to lift, if the lift to extended height was successful, and if the descent of the seat was successful.
Here are images from the first 100 lb load test and then from the max load (405 lb) test.
As can be noted in the above results, the seat was unable to descend on its own until 190 lbs. So, the team performed further testing to find the exact threshold value. The weight was gradually reduced until the threshold was found to be 155 lbs.
Lift Height TestingThe height from the underside of the seat to the floor was measured before and after a lift to ensure that our lift height met our specification of 8 inches. Before the lift, the height was 18.5 inches, and after it was 26.5 inches, which means that our design exactly meets the requirement.
Footprint TestingSome preliminary testing has been done to ensure that our design fits in an ADA bathroom. So far, our design seems to meet our specifications. Below is an image to show our preliminary footprint testing.
Further testing of our footprint gave us the below measurements:
- Depth = 17.5 inches
- Width = 24 inches
So, the overall footprint is 420 squared inches. This value falls within our desires test plans value, so this test was a success.
The maximum distance from the wheelchair to the toilet seat was also measured and found to be 4.25 inches, which is slightly further than we had originally wanted, but was still within our allowable distance.
Risk and Problem TrackingBelow is our updated problem tracker.
Below is our updated risk management.
- (*)Denotes risks added since last phase
- Notable changes to risk management:
- No longer considering strength of the structure to be an issue
- Track-related risks have been removed
- Retrofit is compatible
- Exceeding the budget is no longer an issue