Taming the Tail-Sitter: Hover to Forward Flight Explained
Vložit
- čas přidán 21. 07. 2024
- Thanks to PCBWay for sponsoring this video--check out their website for an instant quote on custom PCBs, 3D printing, or even CNC machined parts: www.pcbway.com/?from=Nicholas
In theory, tailsitter VTOL aircraft are incredibly simple--just add a wing to something like a quadcopter, pitch it over 90 degrees, and cash in on the sweet, sweet efficiency benefits of forward flight. But there are actually 4 key challenges to address in the flight controller for a smooth transition between hover and forward flight.
Patreon: / nicholasrehm
My Website: www.drehmflight.com/
dRehmFlight VTOL flight controller used in this video: www.drehmflight.com/drehmflig...
Tailsitter specific code: www.rcgroups.com/forums/showp...
Drone flight controllers that support transitioning VTOL configurations often simplify the complex task of performing a transition to the flick of a switch. This is awesome for people who like stuff that just works, but terrible for people that like to understand how things work. So how do you actually tell a flight controller to perform a VTOL transition? Rather, how does a flight controller tell the airplane to perform a transition? Tailsitter VTOLs need extra care in the flight controller through their transition, mainly because the definitions of roll and yaw control with respect to the body flip between hover and forward flight. This requires careful remapping of stabilized controls out to the motors and servos, in addition to a flip of the fundamental aircraft frame of reference. Another key to a smooth transition is tuning PID gains separately for each flight mode, and ensuring a seamless and smooth fade between all of these flight mode differences. This video covers how I did this using a little bit of custom code in my opensource flight controller, dRehmFlight. If you found this video interesting, don’t forget to subscribe so you can be up to date on future projects like this!
Intro: 00:00
Flight Controller Basics: 00:54
Problem 1 - Switching Roll & Yaw: 02:58
Problem 2 - Switching Frame of Reference: 04:30
Problem 3 - Gain Staging: 06:58
Problem 4 - Smoothing it Out: 08:04
Conclusions & Crashes: 09:45
#VTOL #Tailsitter - Věda a technologie
I want to demystify these sorts of drone concepts all the way down to the actual implementation. Did seeing the code help, or bore you?
It was super interesting to see the code! Makes it all more clear and interesting :)
Seeing the code was helpful, thanks!
Love seeing the code..... it takes a while for me to understand it.... never boring... I have spent hrs and hrs on your projects.
This was a well thought out application challenges/educational video; however, I cannot help to think if you had simply added two rudders behind the motor thrust-line so regardless of the flight mode you had same control inputs. Any thoughts?
Very interesting. I need to learn to code though.
"Hey look, it's RC test flight"😀. Great explanation of the transition problem.
this video actually took work to make and offers something unique. all RC test flight does anymore is drive around in a boat.
@@dronefootage2778inaccurate
@@dronefootage2778tbh tho im still here for the boat stuff (i started watching in like 2017 for the solar plane project 🤩)
@@dronefootage2778I’m wondering where your great output of high effort work is?
@@GeahkBurchill i just watch youtube
This is probably the most cogent explanation I've seen about tailsitter flight dynamics. Breaking down the problems one step at a time, plus not being afraid to show code, makes this super easy to understand. Excited to see your next build!
Hearing this gives me the awesome feeling of "mission accomplished", thanks a ton!
@@NicholasRehm 🫡 Least I can do when my latest bicopter is powered by dRehmFlight!
Seeing each step was fantastic! I'm especially impressed he was willing to fly all of the intermediate steps that he knew were going to fail. It's so easy to just think through these problems and skip to what you assume is the finished solution, but actually testing the physical response of using a binary transition or not changing the forward flight gains really drives the lesson home.
I’ve been wanting to make a tailsitter for a while now! Great video!!! Keep it up!
Thanks! Hope this inspires you to follow through with it
@@NicholasRehmwhat parameters on ardupilot should we pay attention to in order to smooth and tune our quad tailsitters? Please let me know!
This is the most impressive "unimpressive" piece of foam I've watched in a long while.
The fact that you give such a good explanation into how and why you did things, makes this video to be into a whole other level. It passes from being an entertainment video to be a super good educational video + still being fun to watch. I'm exited to see the next project.
Thanks for the kind words
so smart that you put a timeline on yr advertisement.. I watched the whole ad rather than clicking ahead, because I knew the length.
Yep, I think it's time to breakout the drehmflight board again and play with it some more! You really have made something special here with your software and videos. I appreciate you taking the time to share this stuff with the world
I don't recall how I stumbled upon this channel but I'm happy I did. The way you explained all that gibberish was impressive. Keep doing what you're doing!
Thank you for adding the code in the video. It helps me to understand. I can't wait to see the next video.
Nicholas, your videos are great and this one is particularly excellent. That was a great demonstration of engineering synthesis and how to systematically go about solving multiple problems. It was great that you were able to show how the VTOL behaved under the various steps of the design process.
Thanks for following along!
fabulous video. i really like the progression: stepping through each problem on the path one at a time, and placing the viewer in the mode of expecting each change to be the last one, but then exposing the remaining issues to address
Hey thanks! It was a fun process to work through and I'm happy I could share
Nice! It's always cool to see people who are able to do physical design/builds, complemented with coding skills to solve both problem domains. Really looking forward to your large, folding design!
Thanks! Hoping to have that one flying any day now
@@NicholasRehmI hope it goes well!
That tease of a reconfiguring quad-to-fixed-wing looks VERY cool.
Great technical overview! I purchased Horizon Hobbies Xvert 5 years ago. Great VTOL and performs like your plane for transitions. This plane is a ton of fun to fly and very inexpensive. Keep it up! Love your videos.
Lots of fun tech packed into that plane!
You make such brilliant, groundbreaking videos with some nice engineering work too. We’ll done Nicholas, another one in the can.👍
Thanks so much!!
Well done... Flies and transitions much smother now.
Glad you was able to hear what I was screaming through the screen from the beginning of your video about you need a factor changing the weight of control and two different controllers for diffenent modes. :D
So you basically need 2 FC profiles, different PID values, reference orientation & controls. Neat!
Also, the fade part is smart!
Very nice video ! Especially great that you let us in on the engineering process. ❤ this !
The only thing your “unimpressive piece of foam” needs to be my dream aircraft is a camera, vtx, and code that pivots the camera mount 90 degrees during flight mode transition. Your next project looks absolutely stunning! I can’t wait to see it! Thanks again for all your hard work and for sharing it with us. 🙏
That sounds like it would be a sweet setup. Check out my buddy peter's mini-qbit for something eerily similar czcams.com/video/W0tthPSNnRE/video.html
I suppose a second camera and a PWM-controlled switch would be about the same weight as a servo and linkage, with less mechanical complexity. If the camera switch signal was sent as part of the flight mode transition function, it would make the transition even simpler. Thanks for the video suggestion. 👍
Amazing in-depth vid, thanks for inspiring others!!!
Flight dynamics and controls is such a challenging problem. So many important details!
Great clear walk-thru of the basics leading up to achieving stable transitions. Being able to make reasonably smooth transitions to level flight without airspeed or angle of attack sensors is pretty amazing.
The ultimate test would be to fly the tail sitter through a loop, or barrel roll ... involving transitions to hover at various points in the maneuver.
That would be fun. Wish I had more time to dig a little deeper
Awesome work! Incredible what a single - very intelligent and hard-working - individual can do. Many thanks for the fun and inspiration.
Thanks for the kind words!
No problema señor@@NicholasRehm. Keep up the good work!
I get how a smooth transition between hover and forward flight is better, but dang that sharp transition looks kinda badass, too.
Great project! Thanks for the video, Ill be waiting for more!
Hey thanks!
You are brilliant. Everyone wants to see you build a single-seater VTOL machine capable of 1 or 2 hours of flight time, will essential avionics (com, nav, weather), and some safety features (enclosed blades or jet ; crash parachute...) ; plus a pivoting nacelle - that would be THE airborne motorcycle
That would be sweet
Very well explained! Outstanding! I'd like to fly a foam VTOL like this!
Bruh..... this science of yours seems a lot like magic 🤯 (nice work!)
Hopefully a little less mysterious once its broken down!
It's an interesting coincidence that the CZcams silver play button and quadcopters both have 4 corners🤔👀
Great video, keep it up!
Congratulations. Very impressive.
The code is very clear and simple and well written. Thanks for making that available, it helps see how all this works. Have you done any more on the spinning 3-wing drone. I love the way it looks in straight flight. You left a teaser at the end of "part3" but I don't see anything since and that was a year ago.
Looking forward to your next Tailsitter larger project.
You have a great talent to explains things
Appreciate it!
Well that freaked me out.
I was across the room listening to the end of the video and I hear (seeming to come from someone in the room) “hey look it’s RCTF” and of course the next thing I hear is Daniel’s voice as a video I had started yesterday auto-played. I was utterly confused for about five seconds. Well done lol
That's hilarious hahah
dude, i always love your videos. Now they are getting funny too with your crazy humor😍🤩
This is so GOOD, Nick! 👍👍
As a programmer, as soon as you had the violent transition working I was like, ok nice, the final step is just an easy lerp from hover to forward!
Amazing video, thank you very much!!! Can't wait for the next one...
Thank you man! Great to do :)
Thanks for the arduino version added to the RCGroups page... now to sort the wiring out..... if you only knew the amount of times I tried to set up a tailsitter years ago using other flight controllers....this seems too simple to be true.... now to dust off a few old wings.... and print some more glue on motor mounts..... cheers
Awesome video, excellent well done.
Do a short video on the hardware and programming environment you used for your development, Nice Video
You have some AWESOME videos! Thank you!
Hey thanks!!
Really interesting video!
Love how to showed the code and talked about how. Peeps leave out the details so thanks for the info cause I want to do this shit but I ain’t that so any info is awesome!!
I made this video for curious people exactly like you 😄
Hey, I know you aren't impressed with your "piece of foam", I am impressed. I've been trying to get a plane working but struggling with the balance because I have older, heavier equipment.
Basically, another awesome job! Well done.
Thanks for the comment, keep at it with your project!
great explanation, detailed and clear.
Not sure if you realized, but at the end with the scaling factor you reinvented “fuzzy logic control”
I guess you're kinda right!
Great explanation
Love your videos. You're a great engineer.
Thanks!!
i am impressed man , pls tell us more about this nice piece of foam. :D
great work
Reminds me of something :)
I was planning to try the gradual transition sometime, but using a little simple sin/cos scaling. Seems to me that the relation to gravity magnitude is what matters, and that does not change linearly with pitch angle.
Maybe not gravity... It's true the gravity stays constant but I think the distinction is because regardless of pitch angle, air provides the same control authority from a control surface regardless of the direction that the plane is flying. Air gives the same resistance regardless of whether you fly up or sideways.
I have built my own "tail sitter" I used iNAV in heading hold mode. I find the transition of roll to yaw and vice versa confusing, although given in my case, I don't need it to land in hover; given I have an advantage that my craft can do high alpha up to a hover.
IMO the advantage to roll and yaw switching is in tilt rotors. Still a feat to do it all on your own code.
A very informative video, many thanks.
this is indeed the easiest way to transition. Cant wait for the big project!
great video.
This tailSitter looks so much fun!
I want to build one ❤
I found that you provide the final code over at Patron!
You should totally rebundle this video as a build video, and market it as: a cheap sub 250 project you can build with your kids and have a great intro to programming 🎉
This is basically kiwico without the parts.
And you buy working code by signing up for Patron 😊
"unless you're an investor" 😂
This would be a great way to get beginners flying.
Wow that works really well
Perfect..... are you putting the raw code up like you did with the F35? This would be awesome to have... or is it documented somewhere. cheers
I think I'll be doing a write up on the rcgroups thread and I'll post it there--excited to see what you cook up! Hope you're doing well
That would be awesome....... I have tried a few tail sitters but nothing worked hence the excitement and comment.. Still flying the F35, made a few tweaks to the transition timing so its dialed in and does not dip down when going into FFF..... I have the Nemo set up ready just waiting to assemble the printed parts.. also have another teensy ready to be set up for a small F18...... I was wondering how big a plane you could use this board on as I have a few larger foamies that I want to try it on just for stabilisation.... as for me I just retired 3 months ago and we have been travelling and just relaxing..... if you want to see some of the plane stuff I have been doing since retiring feel free to check out my YTch ... I hope all is well there with you, stay safe and keep up the great work.. BTW I still check in the RCG thread to keep up with what is going on... cheers from downunder
@@NicholasRehm
This is an awesome project! I love things that are mechanically simple and reliable yet work really well.
One thing I don't agree with is the "quadcopter" control layout when in hover mode. As an rc pilot with 30 years experience. My brain naturally would tell me to fly this plane shaped vehicle with an airplane control layout. Using the yaw stick to control yaw as if it was pointing straight up, and roll to twist around the vertical axis.
This would also make the configuration much simpler.
Agreed, sometimes my brain confuses me too being primarily an airplane guy. Thanks for the comment!
Would it help to read forward airspeed using a pitol tube, set a target airspeed, and base your transitional mixing on those.
Great project, results and walkthrough of your process, and learnings. What software do you use for the visuals/diagrams? Cheers!
PowerPoint haha
This settles it, I'm making a Drehmflight FC PCB thats actually made properly. Last time I tried it really wasn't up to spec, but seeing what you can do with it tells me it's worth it to go again.
Check out @michaelrechtin's 3d printed quad project...he made a pretty sweet pcb breakout and I have a few on my desk now. Here is another someone made: github.com/joerenteria/dRehmFlight-PCB
So neat. Is this something someone could pickup and flash to a tailsitter or are there bonus steps?
very cool man. really good break down. I feel you should show more code examples but that could just be my cs brain talking! lol
I'm doing everything I can to work more code in, but people click away real fast once it hits the screen :(
is "yaw" spinning about the vertical axis wrt to the earth? or wrt the plane. new to all this but i was under the impression it was spinning around an axis perpendicular the wings surface
So cool!
Thanks!!
I remember designs for carrier based tailsitters for the US navy in old popular mechanics magazines. Without fly-by-wire they would have been death traps.
Very interesting!
Incredible work! Do you have any thought as to the increase in range in airplane mode. Thanks.
definitely more
Hi, I'm new, trying out a tail sitter VTOL. Am I required to use a CW+CCW motor combination? Or I can just use a CW+CW to make this work?
I would really like to know. I'm so inspired to make one of these. Thanks in advance!
Is it possible to get a guide on how to build the foam Plane?
Vtol amazing. Great movie.
@nicholasrehm thinking about making your own flight controller or a variant of the teensy board with the IMU integrated now that you are working with PCBWay?
Fantastic video, is there a version of the code specifically for this tail sitter, I would like to try building one of my own?
I'll probably post the modified version from this project in my rcgroups thread sometime soon
From Ireland thanks
i wodnering
is it possible when you flick the switch to have a timer like 1-2 seconds where it calculates what boths tates are and does100:0 then slowly fades to 0:100 of the other settigns merging them so it isnt a sudden jerk, but it slowly tilts over i unno, XD
yaaaay i was right, but it was called fading :D and linear transition
Great video. Love how you explained different aspects of the problem the approach to resolve it. I am thinking of buying a teensy and build one of these. Will it work on a nano goblin which has only one motor or will need a lot of tuning and changes to the code?
Sure you can throw it on a nano goblin to stabilize forward flight, but I don't think you'll be able to hover it
@@NicholasRehm thanks for the reply. I was more interested in the hover actually to make the nano goblin a vtol. Any specific reason why this would not work?
@@NicholasRehm will putting this on a heewing t1 ranger hover it? That has 2 motors but a real elevator instead of elevons. I am assuming no. But just confirming.
I have a generally doubt - What is the difference between Normal PID and Geometric PID for aerial vehicles control ? I am a bit confused and It will be very helpful if you can demystify it.
Hi.Any plan available to build this??
any thoughts on the eclipson E vtol>?
Just wondering what motors, esc, and battery combo's you're using here....Oh and keep up the fantastic work!
Cheapest dys sunfun motors they sell on getfpv, some cheap knockoff blheli ESCs from Amazon, and lots of 1500mah 4s batteries. That basically flies 90% of what I build
i liked the violent mode switch more it made a cool sound
could you share the process, code, component , and step you followed for us to recreate those amazing fom project 🎉🎉🎉🎉🎉
Where has this been all my life? I'm putting this control scheme in my AIM-7 for next years FF!
YOU'RE THE SIDEWINDER GUY????
@NicholasRehm I had the big white missile, with the dual drone motors, it was technically an aim 7 sparrow
cool tech 👍
Great Video thank you! Is there a place to get help/share/knowing others porting to ESP32-S3 ?
No, I think that’s a fairly small effort. Teensy is only $20 and no painful porting required-works out of the box
Would be fun to try a servo on a hinged motherboard, change the angle relative to the wing instead of software.
People have definitely done that in the old days of RC flight controllers
Would it not be easier to auto-transition the controls depending on pitch angle instead of a switch input?
yawservo = yaw*sin(pitch) + ail*cos(pitch) type of thing?
Obviously it would cripple aerobatic flight, but that is not the goal i think.
Hi. I want to ask a question about your previous video: "Is THIS the Most Versatile Aircraft Design? (Forward Flight Testing) - Part 2". Could you please explain how you solved camera rotation problem? I want to do it in my project but I did not understand how. Thanks for your help.
A bearing and air brake
wow it is insane
If anyone would like to try designing and programming this in a game I recommend Main Assembly
Very cool.
Hi Nicholas,
Great progress. Have been following your videos for quite a long time and glad to see that all missing pointers of tailsitter behaviour are solved in this video.
I have few queries :
1) How about putting rudder or split flaps for forward flight. Does it creates any major difference instead of thrust vector?
2) Would like to touch base with you for a project. Kindly let me know how to connect with you.
Rudder, split flaps, differential thrust--they all create a yawing moment which is the same in the eyes of the flight controller
Thanks for the revert. Is it possible to connect Raspberry Pi to this for further camera integration ?
I am impressed by the work done. Is firmware based on Ardupilot/BF/iNav or something else? Can I try this FW on my aircraft?
It is my own flight controller code running on an arduino-compatible microcontroller. Check out the link the description to the GitHub repo
"The sensor fusion algorithm is not AI, unless you're an investor in which case it's definitely AI." 👏😂