Snapshot - 2/28/2021

Another snapshot!? Yes, indeed. It is true that I am not releasing highly-technical, bedazzling blog posts at the frequency that I would prefer (I'm not so sure that I've released a single one to date frankly heh), BUT instead of doing some boring self-analysis like I did last time, I'm going to give myself a pass. This is not because of school and covid, but because I feel like I have been making a lot of progress with stuff lately that should soon yield many juicy posts. This is also because I recognize that I need to get better about documentation that supports the creation of blog posts and it takes time to develop habits (ok a little self-analysis.)

Progress with knowledge/intuition with motors (especially brushless, 3-phase ones):

When seeing this post, the first question that may come to mind is where is the next brushless motor design guide post??? This is quite the valid question considering all of the palpable ambition and detail (and lack of pictures somehow) the first installment had. Well, in my continued research of motors, I realized that I had been operating under a very large and very dumb assumption that, when uncovered, made the design guide seem quite a lot less viable. I will announce/explain this in much more detail in my "design guide cancellation" post so stay tuned. Additionally, I am now very happy with my intuition of motors electrically, magnetically, and mechanically. The whole shebang, if you will. There used to be one thing on the magnetic side of things that didn't make sense, but I thought about it really really hard and read some material and now I've got it. That's all it takes. Just think harder.

Progress with the 3 phase, brushless motor controller board/I can use EAGLE now:

Yes I have finally delved into the world of printed circuit boards and, like everything else, they now seem much less cool now that I am intimate with their manufacturing and operating principles. I have stolen the great idea of Ben Katz once again and am making a shield for a Nucleo board centered around TI's DRV IC. Here is what I have so far: (yes, a picture!)

The headers are in the right spots but not all of the smaller components are in their final resting positions. Everything should fall between the headers in the end for a nice, compact layout. I have some changes to make at the schematic level as I have learned more about STM32s and how their clocks/timers work. Things seem to be going ok right now, but I'm probably going to have a hell of a time getting it running since it's my first board.

Progress with STM32s and microcontrollers in general:

Many an hour of my time has been spent on becoming acquainted with the STM32 development environment after I was handed my lab's motor controller dev board (I volunteered in truth) and told to make sure that it still worked with some of our actuators. Most of that time was eaten pinballing between too many resources at one time, trying to figure out what all these dang acronyms are and what they really mean. HAL, API, and driver I shall never forget the definitions of in this context for the rest of my days. But now I can implement some cool stuff and I can semi-easily look up how to do other cool things that I have yet to try. I am truly sick of going through resources and I'm finding myself not really wanting to write about it much either right now haha. More stuff to come from these microcontrollers certainly.

Progress with Odrive I guess...:

Another thing my lab had me do was characterize the brushless motor that we were planning on using. Well the lab had Odrives and I had an Odrive so we said "it's Odrive time." It was not Odrive time. My labmate and I ran into several consecutive problems and were met with alarmingly little documentation. In fact, the documentation that would help us the most was in disjointed forums. We were only trying to get the barest of results, so we eventually simplified the procedure to this:

Motor fixed to a waterjet aluminum plate which is clamped in the vise to keep it from going anywhere. 3D printed shaft extension pressed onto the tiny, originally 3mm shaft and long enough to where the encoder (just chillin in front of the motor on a printed stand) can be spaced far enough away that we can access the mounting holes on the stator and attach the torque arm. The force gauge seen on the left was hooked into the notch on the arm and read out force values. The first time we tested, my partner and I just read values off of the forge gauge screen and spammed the read current function in the Odrive command line tool. Frankly, that worked pretty well, but we came back and read values out at a consistent interval onto an SD card and with a python script (that I did not write) and plotted it very nicely in excel anyway. We were only testing in the 3-4 Nm range so we didn't even need to clamp the vise down. Here is a video of the motor spinning a little bit. Also the first upload on my channel!

Edit: Here is the plotted data

Progress with quick, cheap, and dirty design/fabrication/assembly techniques:

I have always been interested in this area of knowledge because it literally forms the means by which you create. Furthering my education in this direction is the main reason why I joined the Invention Studio. However, I can now say that passively learning a bunch of stuff and retaining it just because it's happening around you doesn't really work for me. I still have to be focused and do things myself to really understand them. One of the graduate students in my lab recommended this instructable by Charles G. Truly a legendary resource for someone in my position. This also led me to the FUNdaMENTALS of design course. Another great resource and Prof. Slocum is a joy to listen to. Legitimately hilarious at times. I highly recommend both of these resources for anyone getting into mechanical/machine design and look forward to applying all of the tidbits that I picked up in the future.

Progress with delicious, delicious food:

Didn't see this one coming, did you? I'm going to finish this post out with a veritable photo dump in an attempt to convince myself that I have been doing things in the last two months. One of those things being cooking because my roommate KEVIN and I are feeding ourselves for the most part. Here is the best 'meal' we have made thus far (full credit to KEVIN for the idea):