Fish4Fun
So long, and Thanks for all the Fish!
So I have been playing with some small sensorless BLDC motors (hobby small, not industrial small, lol)......I have read tons of white papers and application notes and certainly understand the how and why of sensing the zero crossing point and all of the caveats, foibles and pitfalls therein....but I like to test theories....so I decided to see if I could simply drive them synchronously.....truly sensorless as it were.....and it works amazingly well....as long as you take the time to "tune" the code to the motor....
For the preliminary testing I dumbed it all the way down.....I used a CC/CV bench power supply and an Arduino to drive the H-Bridges....Like a traditional ESC, low RPM lacks torque, but in the "mid range" and right on up into the "upper range' self-starting is reliable and RPM is by definition exactly what it is suppose to be.....
What's my point? I guess I am a little curious why there is absolutely no mention anywhere of running these cute little motors synchronously....yes, it requires a little bit of "tweaking", but is that really a huge deal? Take the quadcopters for example.....trying to use servo pulses to adjust each motor just doesn't provide fast enough // accurate enough results....so there are "special" quadcopter speed controllers that require sophisticated programming of pretty robust micro-controllers to do what an ATTINY can do if the motors are driven synchronously....maybe I am missing something???....I know it isn't what they are designed for, and it certainly isn't a "drop-in replacement" for ESCs, but I can think of a whole host of things that these little motors would be great for if there were a simple way to DIY an ESC....
Anyway, I am sure there is a good reason why I can't find anything to read on the topic....but it sure is easy to make them spin......By all means feel free to correct me//comment...
Fish
For the preliminary testing I dumbed it all the way down.....I used a CC/CV bench power supply and an Arduino to drive the H-Bridges....Like a traditional ESC, low RPM lacks torque, but in the "mid range" and right on up into the "upper range' self-starting is reliable and RPM is by definition exactly what it is suppose to be.....
What's my point? I guess I am a little curious why there is absolutely no mention anywhere of running these cute little motors synchronously....yes, it requires a little bit of "tweaking", but is that really a huge deal? Take the quadcopters for example.....trying to use servo pulses to adjust each motor just doesn't provide fast enough // accurate enough results....so there are "special" quadcopter speed controllers that require sophisticated programming of pretty robust micro-controllers to do what an ATTINY can do if the motors are driven synchronously....maybe I am missing something???....I know it isn't what they are designed for, and it certainly isn't a "drop-in replacement" for ESCs, but I can think of a whole host of things that these little motors would be great for if there were a simple way to DIY an ESC....
Anyway, I am sure there is a good reason why I can't find anything to read on the topic....but it sure is easy to make them spin......By all means feel free to correct me//comment...
Fish