tomstanton
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Swashplateless Helicopter
🕑 Added 2020-06-15 20:33:08 +0000 UTCHope everyone is well! I've been busy working on a helicopter that uses a single motor for control. Conventional helicopters require servo controlled swashplates to adjust the blade angle during it's rotation. However, this setup varies the motor torque causing the blades to lead/lag, which adjusts the blade angle due to the 45 degree hinge. It's taken a lot of problem solving to get this system working and I've just test flown it today for the first time (it still needs quite a bit of tuning). Now I need to put everything into a final video, but first, a quick run down of the system.
The motor is a standard brushless motor (Tarot 4006) and is controlled with an off the shelf drone speed controller (T-motor F35A). There is a diametric magnet epoxied to the bottom of the motor shaft, and a magnetic encoder mounted 2mm below it. This measures the exact angle of the motor 2500 per second (75 measurements per rotation @2000RPM). Then a Teensy 3.6 board runs an arduino code to read the angle and apply a Sine/Cos wave output to the throttle setting. The amplitude of the Sin/Cos wave determines the amount of roll/pitch control. This throttle output value is then sent to the motor controller 500 times per second and acheives full cyclic control!
Here is the original source of this concept: https://youtu.be/aEPf0QHVuMM
Comments
Jacob Lov
any chance you could publish the files from this project, particularly how you manage the blade acceleration. i really want to try this, but am not a wizard like you
Max Bursell
HI Tom. I realy love watching your videoes. Do you know the name of the altimeter sensor that you used in the golfball altimeter projekt? I want to get the same altimeter and do make something. I have tried other altimeters but dont seems to get good results. I will realy appreciate if you could provide me with the name or number or something to identify the altimeter you are using. thanke you :) Best regards Max Bursell
Tom Stanton
I believe I read somewhere in Jimmy's research that he considered a compliant mechanism design for a micro version, but he didn't get round to trying it. I'm sure it's possible with the correct material as when the helicopter is tuned well, the hinges barely move in flight. Also maybe a compliant mech hinge might remove the friction issues. I need a break from this helicopter for a while, but might try it in the future haha
Tom I know you said you wouldn't share all the plans and code because of the patent concerns, but would you share the overall heli design? I'd love to try and replicate this. My guess is newer flight controllers have enough built in compute power to roll all of this code into the main CPU.
Dyu think a compliant mechanism rather than a hinged mechanism would be sufficiently novel as to be out of the scope of the patent..? Might be a tall order for FDM but if you wanna have a go at it in SLS or DMLS hit me up
lol , missed that one!!!! thanks mate!
Angus Ross-Thomson
Fascinating concept, some really original thinking. Overcoming the cross-couplings inherent in rotary wing aircraft in forward flight will be great fun, lots of in-flight computing power should be able to sort it though. Can’t wait for the full video.
Tom Stanton
If open up the Arduino library manager and search AS5X47, there is a library that works well! I had to assign the SPI pins on the teensy, but worked straight away with Pro micro.
thanks Tom , I have a couple of am's earler devices for a windvane design, going to have a closer look at this one, SPI on the arduino w/o a libray can be a little tricky!!!!
Tom Stanton
Hi Adrian, I used an AS5047 encoder https://www.digikey.co.uk/product-detail/en/ams/AS5047P-TS_EK_AB/AS5047P-TS_EK_AB-ND/5452344
hi Tom, what magnetic encoder did you use please?
Very interesting, can't wait for the video
