Note: Our team has compressed our images, but the image upload quota is still full, so this report does not have photos that we would have liked to attach.
This week, I made adjustments to the servo mounting, and added in holes to accomodate the heatset inserts to the lid of the sensor cavity, the walls of the sensor cavity, and the walls of the main body of the Visor. I printed out the sensor cavity lid so that we could have some practice with using the heatset inserts for mounting our sensors. We ordered M2.5 heatset inserts this week as well since currently we only have access to M3 inserts, but some of our parts require M2.5.
I also printed a section of the main body that is the connection between the sensor cavity and the main body. Instead of the plug connectors that we tried last time, I adjusted the model to have fingered tabs so that it is easier to print accurately and also sand down for a press fit. The test print worked out very well. With this print, I also fabricated more servo ships so that we could test the fit with the servos. It ended up being such a good fit that we used this iteration for testing our air dam system durability.
My tasks/subsystem is CAD and Physical Design, so for the physical fabrication of the sensor box, the tests that we have planned include weather testing, durability testing, and bike mount testing. All of these tests are integral to the data gathering function of our SNIFF project.
Of tests that have been done, we have tested the durability of our air dams. We tested that the air dams are robust by seeing if they could sustain 10,000 actuations with a 0.5 second pause between actuations and 2 minutes between batches of 1000 actuations. There was no change in the servos, dams, rails, or sensor cavity, which meant that this test was passed and this aspect of our fabrication met our needs for design and use-case requirements.
The weather testing and mount testing are to be done in the coming week.
To test that the Visor is resistant to weather we will be removing all sensing components leaving only the dams in place and subjecting them to the flow of a shower. After measuring the flow from one of the team member’s showers, we found that it was equivalent to a 1.5” per hour of rain which is a significant storm that can occur in the Pittsburgh area. Success in this test would be that less than 100mL of water was able to enter the air quality cavity and the rest of the Visor internals are dry. This 100mL number was obtained by examining our cavity design and determining what water level in the cavity the sensors would still be safe. If this test fails we will examine the location of water ingress and improve the water seal at that point of ingress.
To test that the Visor is rugged enough to handle road vibrations at 20mph, we will ride a POGOH bike with the Visor for 3 hours cumulatively while trying to maintain a high average speed. After this test we will inspect the Visor and its mounting solution for any damage and excessive play in the mounts. Success in this test will be that the housing is undamaged and that the mounts are still secure. If this test fails we will examine the point of failure and reinforce the housing or mounting point.
Next week, I hope to get a version of the entire Visor printed and put together, as well as get some testing in for not only the durability portion but for data collection.
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