Hi, my name's Riley. I'm new to ornithopters and just received my spybird. I hope I will have a continuing interest in it. Anyways hi everybody and I hope to be here a while.
Here is an ornithopter that I found that I do not own but looks really interesting: http://world.taobao.com/item/5202400...714.0.0.Xux6VS
I saw an ornithopter design like the one you show, this was a while ago just after the Festo smart Bird appeard on Youtube.It flew so gracefully.
It seems the design is simple, just a frame of carbon parts, the main part is the controller. As far as I could identify it is only sold as package with RX and the price would be app. 700-800 USD. Unfortunately I have no idea if it's sold internationally...
If someone does end up buying one, please post back here with results. It seems like a good design and some close ups and more detailed specs would be nice.
Oh, here is anther good link for the orni in the video. From google translate, it looks like it's an attempt at a Festo Smartbird clone.
OK, I think I'm going to try my best to rig up a cad file for this bird. I am starting with simple 2d rigs for the wing mechanism until I'm satisfied with a good one. Anyone have any opinions on this?
I already started the same at SolidWorks -flapping mechanics done, dimensios of the wing and body bit trickey :-)
There are enough pictures to estimate parts and dimensions, but the controller program for flapping is (at least for me) the biggest hurdle...
I agree that it does fly very gracefully .... but for me the wing planform and especially the airplane-like empennage totally kills the "seagull" illusion. I'd change the color, appearance, etc., and call it something else.
drayon, I'd love to help out with the 3d design. The controller program isn't really necessary, as everything is handled by a 4 channel reciever.
AFAIK there are 2 servos for the tail, rudder/elevator, and 1 in each wing for both ailerons. The only control you would need is to seperate the aileron channel, as it is by default designed for one servo in the middle controlling 2 pushrods. And of course 1 ESC for the brushless motor powering it.
I have the most trouble finding gears. If anyone can identify or know someone/somewhere who can, I'd love to find out if those are standard gears that I can buy. I'll post screenshots and necessary pictures of the gearbox after this post.
if someone can take this and download the individual photos that would be great. That format is laggy and slow.
Here is my progress in analysing/drawing the gull mechanics. I can confirm your finding of the movement angles...
Only thing I don´t know are the dimensions from wing tip to ellbow and I have no idea how to couple the outer wing to the twisting servo...
I thought tht the two servos in the wings are for actie twisting as Festo did and not for simply steer the bird. So I assumed that there is a controller needed to transform the flap frequency (from ESC input) to the right position of the wint twist - and mix it of course with the aileron input... otherwhise there would be no active twist and little forward movement (but those are just assumptions from myself..)
Actually, I thought about it again after I posted that, I think you are right about it being actively twisted. Their brochure mentions using the inner wing for lift and the outer wing for propulsion, and there is a little graph of wing position vs angle over 10 flaps or so. I suppose there may be a way to get position feedback from the esc just like with a stepper motor, but that would take a lot of work. More likely you would have to include either an encoder on one of the gears, a potentiometer on one of the wing base joints, or imo the best option a few magnets on one of the main gears and a hall effect sensor , as then you wouldn't have to worry about finding an encoder that fits.
I was actually looking into gears thought that the tarot 450 main gears were a good option, as they are readily available and have a bearing with a fitted hub that you can get with them and screw on any c.f. playe or other gears to that, but it looks like you included (custom?) gears in your design. It looks great! I really like the wing joints especially.
Regarding wing twist, do you think the ribs should twist around the spar, or just assume the epp is strong enough to bend the thin carbon fiber at the end of the ribs?
If you want I could try to write some software for the wing twist control and potentially gliding if the ratchet hardware is ever added. Imo the best option would be to use a attiny (or pic) and have it read the ppm stream from the receiver, so You can set up more channels for adjusting constants like wing twist on the fly (get it?) And still have 5 or so pins left for i/o left not counting any expansion.
5 servos plus the motor could all fit on one pen expansion chip, and leave plenty of pins for hall effect sensors or encoders.
Edit: for mounting the servo, I would probably cut the outer disk off of a servo axle mount disk thing, so you could just insert the remaining cylinder into some 3d printed/cnc'd platic piece that would fit over the end of the spar. Then I'm the last rib instead of leaving a hole for the spar, have a servo sizes hole with the mounting holes to just attatch the servo on. You would likely have to *not* glue the other spare in place on the forewing, and instead out stoppers on either side of each so they can twist around the spar. The epp foam should be sturdy enough to invoke the twist in the other ribs just from the powered twist in the last one.
Edit 2: 1:2 seems like a good ratio, but I might lean more to 1:1, as that's what hiro(I think that's his name) did. But his most recent bird seems to be 1:2 if not more, so Idk what the optimal ratio might be a matter of just trying one and adjusting until it works best. It shouldn't be too hard to replace the spare on the inner wing with larger or shorter ones, but you'd have to add more ribs and reapply the epp.
Edit 3: just looked at your design again and realized you have the servo on the inside of the outer wing. If you put it on the outside so it only rotates the last rib, mounting will be easier and the epp will distribute the twist along the other ribs. The only disadvantage would be shifting weight farther down the wing and put more load on the gears/motors, but I can't see another good option.
I used the same quantity of teeth in my gears as Hiro did. But there is room for change as e.g. Festo used 3times the same gear... as far as the flapping frequency stays the same, it should be ok to change the gears...
I would mount the last rib to the carbon rod and positio the remaining ones to be rotateble so the epp shall be twisted because of the last rib and transmitt the movement to the other ribs (linear...). But I´m new to ornithopters so there is a lot of assumption, trial & error and learning in all I do.
Great idea, I thought about an arduiono mini or nano as I found a sketch for a glide lock here in the forum. My idea was to try to include the flap twist there but I´m just a mecanical guy with nearly no experiance in programming.... :-(
.... for mounting the servo, I would probably cut the outer disk off of a servo axle mount disk thing, so you could just insert the remaining cylinder into some 3d printed/cnc'd platic piece that would fit over the end of the spar. ...
Good point - I have an Ultimaker at home so no problem with 3D-pring but I have not idea how long the parts will last/how durable they are in frequent movement.
I would love to have a wing design like a real bird and not like an airplane so I also guess 1:1 might be more realistic.
It was a first assumption, because I have not converted the ribs from the pictures - but that´s a good point. Thank you for that idea !!
I'm thinking about tail design, do you plan on doing a smartbird type tail, or one like but I with a vertical stabilizer? Or one like on kazu-kakatu's ornis or sk's?
On a side note, I've been thinking about body design; I wonder how practical vacuu-formed is, as you get complete freedom and the ability to use transparent plastic.
Also, definitely move the servos to the wing tips. The twist can't originate in the middle of the wing or else you will get a lot of shearing.
Regarding position feedback, there are a lot of options. You only need to know when the wing is in the highest or lowest position. For this use either microswitches or two magnets and hall sensors. For hall sensors, you could go with 1 and two magnets, but you risk having errors that lead to a bit flip of up/down. Best to have two sensors 180 degrees apart on one main gear and 1 magnet, so you can tell if the magnet is on the top side or bottom side and get wing position from that.
If you are in the Kerrville, TX area our San Antonio, TX location is conveniently located just a few miles away.
RC Health Services has been conducting CPR, BLS, ACLS, and PALS courses in San Antonio for many years. Our reputation for providing top quality American Heart Association training is known throughout the San Antonio Metro area. Students attend our BLS for Healthcare Provider courses, CPR classes, ACLS (Advanced Life Support courses), PALS (Pediatric Advanced Life Support) courses, and first aid training on a daily basis. Our new, convenient location is just 5 minutes south of Loop 410 in San Antonio.
The ACLS Class is taught by top level registered nurses and paramedics with more than 50 years combined experience performing in emergency situations. They apply their experience to help facilitate the learning process for the student during the course.
We offer a series of ACLS and PALS preparation courses via our online portal. Courses include online EKG for both the adult and pediatric cases, in-hospital and out-of-hospital stroke courses, and the Learn STEMI course. All of our online courses earn continuing education units for nurses, paramedics, and physicians.