Maybe the moderators are not as skilled as Sparky and could not move just the last part of the thread to the debate-zone.
I would like to see the technical info returned to this section. Sparky can you help?

-Chris

Well said Igor.

Still Kim's original post is of interest to many of us that are interested in electric powered control line. Let us not begrudge him a chance to show innovations, that he is working on, to those of us interested in them. Putting the thread into the debate section does just that. Persons most interested in his activities are mainly those of us that frequent the "Gettin all AMP'ed up" forum. I personally do not pay any attention to the Debate forum nor do I usually view the forums on construction, finishing etc.

Mike, Point taken.

I must say that the negativity towards the idea and the veiled implication that I might be cheating if I used such a model and put in a very good flight has left me questioning whether any further effort in this regard is warranted. You are certainly entitled to your opinions but not to disparaging my character.

  I haven't seen anyone suggesting that you are cheating in any of these threads (nor the one before). And in fact, since there are no rules preventing any possible functionality of the system, it's literally not possible to cheat as it currently stands. Using a fully programmed autopilot is current LEGAL and there is nothing to prevent it in the rules.

   What everybody is concerned about is autopilots. As I mentioned when this first came up, *autopilots are going to be banned*. I don't think you are likely to disagree with the point we don't want an autopilot doing autonomous maneuvers while the pilot just stands there.

   The problem remains, as Igor correctly points out, and taking as a given that autopilots are going to be banned - *how* are you going to ban them? One way certain to work is to require mechanical connections. It's a crude response, it unnecessarily disallows your fly-by-wire system that most of us think is OK, but it certainly bans autopilots effectively.

  As previously, if you don't want your fly-by-wire system to get banned it would be worth your while to put efforts towards a rule that permits yours, and still clearly prohibits autopilots. I think that is more important to your cause than developing the fly-by-wire system further. I have been thinking about it for ~15 years now, and I still can't come up with anything better than "mechanical connections" but unless you do, your system is going to get banned, too.

   Brett

What I have trouble understanding is that you and all members of the AMA have for decades taken a person at their word that they were the builder of their own model. If they declare it so then it is. Why should this be any different

  Probably shouldn't be, but I can tell you there are people lining up to write that proposal. It was rejected before, maybe it will again, but I wouldn't count on it.

   You have a point about trusting the competitors. But, BOM is actually a rule, and you have to lie to break it.

    With this, there is no rule at all right now, so no rule to break, an autopilot is absolutely permitted as it stands today.  I presume that you would suggest "electronic coupling of the flight surfaces shall limited to causing the surfaces to move in proportion to the bellcrank deflection" or some such. That might be a viable rules proposal. THEN, your theory about trusting the people to not cheat would be one possible outcome.

    But you need to make the argument and convince people it is workable. Starting by stating that people are trying to conspire against you is not likely to bring people to you point of view.

    Brett
   

How do you "prove" that you have no auto pilot, how do you "test" a system to prove it is not autonomous?
Brett, if there is a rule banning autonomous control systems, then yes it would be like the "bom" rule.
Thoughts?

  Kim's test (hold the leadouts and move the airplane around and see if it reacts) sounds OK. Of course you could have the timer enable the system at motor start.

    I don't think, the way the stars are aligning, that it will be like BOM, because I think the overwhelming likelihood is that anything but mechanical connections are going to get disallowed. Not because of any sort of vendetta, but because no one can think of anything better that is sure to work. I don't necessarily advocate that, but that's what I expect to happen.

    BTW, what we mean by "autopilot" could mean almost anything from weak stability enhancement, to full-on automatic flight. Typically we use it to make the control input a "rate command" system where the bellcrank angle represents an target angular rate, which is then achieved by a combination of feedback sensors. I am not entirely convinced that this is a bad thing, but I bet I am in the minority. It's a very small step from there, to generating the rate commands to perform a perfect maneuver automatically when triggered. Everybody agrees that this is not acceptable.

     Brett

Berkeley had a model back in the 1940's or so that had mechanical flight stabilization. If you are going to have a rule to eliminate electronic stabilization then you also need to include mechanical stabilization as well. It had a pendulum to augment the user control inputs. It was the Berkeley "Bug" and the control system was called "Autotrol."

-Chris

I think everyone is making a mountain out of a mole hill. It is a huge jump "HUGE"from this to any type of pre programmed flight system.

  No, it isn't. It's actually quite simple once you have a processor in the loop, then it's just a matter of software. Plenty of people already know how to do it.

    Brett

Go ahead, propose your little witch hunt rules that suppress free and independent thought.

You are right Brett I won't win any converts to my opinion with such volatile rants.
I apologize to the forum and retract the statement.
Sorry.

I just feel that the all out ban on anything but direct mechanical control will jeopardize the future of stunt.
We are presenting our passion for precision aerobatics to a new generation, a digital generation who I believe want to be able to endlessly "tweak" things to make them do what they want them to do.
I'm sure that many new flyers would embrace the technology.

That, I think, is a stretch.  To do an autopilot that could beat one of the world-class guys would take a lot more than just the ability to string a few lines of code together.

  Well, you would certainly have to do some math, but it's simple enough.
 
    Brett

Well I think it would take more than just a processor in the loop. You need appropriate sensors to detect altitude, speed, and directions. However there are flight computers for quadcopters and such with the necessary hardware, and at reasonable cost.

  Absolutely! To first approximation, you only need gyros. Make the deflection of the bellcrank represent the commanded rate, command the servo to a value proportional to the bellcrank deflection, and then add to that the difference between the rate command and the gyro rate. If the rate deviates from the desired rate, the gyro corrects it. That's a reasonable, simple autopilot design, that would make the airplane much easier to fly because you no longer have to pay much attention to whether or not your control input did what you expected.

    Now, replace the bellcrank input to this system with something that, when triggered, generates a fixed pitch rate command, and integrates it until you get to 90 "steradian degrees", then sets the commanded rate back to zero. Trigger with "hard-over" bellcrank position, below hard-over, it works like it did in the previous example. Now you have a perfectly programmed square corner, repeat 4 times, perfect square, correct for drift by changing trigger points.

   That could be done with a very minimal processor contained in the postulated "black box".

   If you want it better, then start adding accelerometers to create a "strapdown" inertial reference, then you won't have to correct for drift due to wind any more and can program complete maneuvers.

    All this sort of processing is quite simple and people have been designing systems like this for more than 50 years for satellite control and rocket guidance. The Atlas missile guidance system autopilot worked pretty much exactly like the simple system above, the guidance law output was a body angular rate command that was implemented with a feed-forward (the bellcrank angle generating the control deflection) and gyro rate feedback to correct errors in the open-loop feedforward. The guidance was external on that one, based on riding radar beams early on.  Which brings up the other half of this that no one has mentioned - our  soon-to-be-permitted 2.4 ghz radio links. Which could provide the external reference to make the thing entirely automatic.

   It would take some work but all of this is well within the state of the art.

    Brett

So the tech exists, banning it won't make it go away.

Personally I can hardly wait for a fully programmable over the counter control system.

   Why? What is the point of doing that, aside from showing you can do it? If you buy it turn-key, you are showing only that someone else can do it. But no one cares what you sport-fly with, enjoy it however you wish to. Contest rules are not going to matter for sport-fliers.

   Banning it certainly will make it not show up in a contest environment, which is where the problem is. Virtually no one wants an autopilot to be legal, Kim included, because it fundamentally alters the event. Autopilots will be made illegal, period.

Given that, if it requires banning fly-by-wire systems unnecessarily (because we can't come up with a better way to ban autopilots than "mechanical connections")  that will be what happens.

    Brett

Kim,

I just gave you a + to get you out of that -1 hole you were in. A hole I know all to well. 

I was at -375 once, remarkable but true! Tell ya, it's dark and lonely down there.  Really dark and really lonely. You can't dig your way out of a -375.

Model airplanes, will they ever be X-rayed? Scrapings from under the nails to test for BOM?

Anyway, I have interest in anything electric, and expect to enter that "cave" shortly. Shortly, well, hopefully before I die. Got some engines to sell first.

I like and have interest in what you're up to. Kudos! 

That servo thing operating the control surfaces. I know it quite well from R/C pattern and it works. Not sure for CL, but please, you will keep us informed.

I'm always late in Threads because I don't like to read. So, at first, I thought you eliminated one of the handle lines. Hey! That thought worked for me. 

In all honesty, when I saw your magnetic bellcrank, I was at first disappointed. I'm over that now and, two lines or not, I'm still interested in your endeavors, .

Can you get it down to one line, one servo and a "joy" stick?

Hey! I got your back with that +.

Keep up the good work!

Charles

There are some nice conveniences available for a fly-by-wire system, I think.

If you want a removable wing on your model, it is a lot simpler to do if there are no mechanical control linkages. Just an electrical connector and a few nylon screws to hold the wing on.

Plus if you want to play with control ratios flaps/elevator, you just modify program a bit. Also if you want a response curve on your elevator or flaps that is not linear (say exponential or logarithmic) it is easily accomplished in software. No fancy machining or mechanical design.

-Chris

Chris, You Nailed It Exactly!

As for moving the thread - the original thread had nothing to do with electric power for models.  It had to do with control systems ...

as does this one.

Hi Kim:

First off, please do not blame Dean Pappas for moving this thread from the All AMPed Up section; I did it. As Mike Anderson so correctly posted, this is not a subject that is about electric models. It's about control systems, and, as the posts here have shown, it is a subject ripe for debate.

If you were to look at the one post I did make about your system on the All AMPed Up section, you would see that I was one of the few who not only defended you and your system, but also applauded you for it.

I see forums as a vehicle to help those who need questions answered and exchange ideas. I feel that subjects that spur strong debate should have a section where debates can take place without confusing or scaring off newcomers who only want their basic questions answered. If they see too much arguing between experts, they just might pack up and leave. That we cannot afford; we need all the newcomers we can get.

I feel that this is an important subject and one that will be the test case for future electronic advances that might improve our mode of flying. Sparky did the exact right thing in forming a new forum topic for it.

Kim, I'm not your enemy. I see and understand your path, and highly applaud it. It's just not something that needs to be, or should be, part of the electric propulsion discussion. You should have originally posted this on the Open Forum. While I don't consider it rude that you didn't do that, I was disappointed that you chose to inject another highly argumentative subject into a forum that deals with an already sensitive subject to many.

Bob Hunt

I didn't say "autopilot" I said "control system".
I don't want an autopilot any more than you do.

None of us can look at somebody else's electronic control system and tell whether it's a straight open-loop control, augmented control, or an autopilot.  That's the problem. The only way to draw the line is to forbid electronics in the pitch axis.

Some may say that accelerometer based throttle control is autopilot.

It's an autothrottle.  That's what it's known as in the industry, anyhow.  Now you have to have one to place in the world or European championships or to win the US Nats. The effect of automation in pitch would be much more than for propulsion. 

Some may say that a mechanical device to change you rudder in turns is autopilot.

Obviously not.  Writing the rule to ban electronics would allow such a linkage.  It's a simple distinction.  Using a yaw rate feedback to control rudder, as has been done since the early days of swept-wing airplanes, and as Igor has done with a stunt plane, is a different matter.  My people would call that a stability augmentation system.  Whether to allow a SAS in yaw and roll is a separate subject than allowing electronics in pitch.  I would recommend banning electronics from all aerodynamic control surfaces.

Pat, that what you say is not enough. You probably did not read argumentation while we spoke about it in rules working group. We also do not want preprogrammed open loop clock work, not only feed back systems. We cannot say "it is compliant" because we even cannot define what is and what is not allowed, because there is not clear line between "controlled by pilot" and "autopilot". This what you wrote is clear example. We not need to see only rocket technics with gyros and accelerometers. I can say for myself, that on latest ECh I got marks between 8 and 9 for almost all figures. But I got twice (from 7 official flights) mark 6.8 for not so well done 60 degrees turn to triangle and hourglass (it was not so bad, but some judges simply want cut top guys for even small mistake to make clearer differences). I wrote it somewher in another thread and I posted also my score sheet, it is well visible. So for me it will be very very helpful a small function which will trigger preprogrammed 60 degrees turn when it sees that I do first corner of triangle or hourglass. This will give me may be 5 or 10 safe points what will make me good sleeping front of Richie and Alex. This is in my eyes clearly unfair, but I can still say that I send my pilot commands by lines to model. And even IF we can find clear wording to disable this then we cannot find way to inspect it. Because it is PROGRAMATICAL solution. You cannot see it on PCB, and you cannot check it on ground.

And why we want it stop as soon as possible? You know how much effort it costs you ... so that is reason, those who can do it also will must develop it if they want to stay competitive and those who cannot, will think if they want continue. We simply do not want to kill event with solution undoable by average pilot or builder.

Pat, again and again ... this is about stunt rules, nothing else. When I saw it first time, I did not wrote to Kim (or anyone else) that he is "bad guy". I wrote to working group and triggered speech about it. Result is that the best way is to allow only mechanical way from pilot to any control surface. And why? it is pretty simple and practical - because for passed 50 years no one invented useful autopilot. So we believe no one will do it also in next 50 years, while only existence of FBW opens in all heads how to use gyros, accelerometers and other tricks. I know you spent lot of time with FBW and you do not want to throw it to trash, but you knew long time that it will have strong opposition, that is why I opened it immediatelly I saw it first time. It is not plenty of time to formulate rules, as I see it is already too late.

But tomake it clear and I wrote it already, I do not see problem with FBW itself, if FBW will allow newcomers to start safely as Kim wrote, it will be very good, so simply do it, I will welcome it in area where it helps, I simply do not want to push stunt to programmers event for 5 people of planet.

Without all that "tech" the only thing you can do is simply preset the amount of deflection and hold it for a certain period of time.
The end result will be about as good as a blindfolded pilot would be capable of accomplishing.

   No. If I take a reasonably accurate (over the period of 200 msec) gyro and integrate the output, I can make it do a nearly perfect corner. You couldn't do a whole flight that way, but the effect of drift would be negligible and the scale factor error could be calibrated out. We do it all the time. It would be open-loop, but dead-nuts repeatable. You could get it right in a few flights.

   With enough radio links, you can do what you can do with multiple cameras. A completely passive tracking array could be generated using 3 transmitters and a properly-designed antenna and tracking system in the airplane. It could be as accurate as half a wavelength, which if I did my guzzintas right, is about 2 3/8". Easy - no, but certainly possible with sufficient trickery. Since there will be nothing preventing a 2-way link, all the processing could be on the ground.

   Of course, I also know how to jam such a system, so if you see me with a 5Kw spark gap transmitter, that's why.

    Brett

 

   No. If I take a reasonably accurate (over the period of 200 msec) gyro and integrate the output, I can make it do a nearly perfect corner. You couldn't do a whole flight that way, but the effect of drift would be negligible and the scale factor error could be calibrated out. We do it all the time. It would be open-loop, but dead-nuts repeatable. You could get it right in a few flights.

   With enough radio links, you can do what you can do with multiple cameras. A completely passive tracking array could be generated using 3 transmitters and a properly-designed antenna and tracking system in the airplane. It could be as accurate as half a wavelength, which if I did my guzzintas right, is about 2 3/8". Easy - no, but certainly possible with sufficient trickery. Since there will be nothing preventing a 2-way link, all the processing could be on the ground.

   Of course, I also know how to jam such a system, so if you see me with a 5Kw spark gap transmitter, that's why.

    Brett

 

You are making my point, thank you.
Gyros or radio links = tech.
Already prohibited under the rules and not a part of our system.

My point was that a FBW system as allowed under the current rules incapable of doing a pre-programmed 60 degree corner.
Or maintaining level flight, or any of the other things some seem to fear.

Pat MacKenzie

My point was that a FBW system as allowed under the current rules incapable of doing a pre-programmed 60 degree corner.
Or maintaining level flight, or any of the other things some seem to fear.

Seems to me that you are really trying to keep open doors for such things. I am surprised you are trying to say something is not doable without trying I wold never say such thing, because I saw "undoable" things many times in my life.

Such preprogrammed maneuvers are successfully done in R/C world may be 20 or 30 years ago. By simple timers. I saw perfect and repetitive rolls always finishing in perfect level position with F3A airplane and timer executed by simple button. So it is obviously doable and replacing muscle memory be electronic device does not have space here in my eyes.

You are making my point, thank you.
Gyros or radio links = tech.
Already prohibited under the rules and not a part of our system.

My point was that a FBW system as allowed under the current rules incapable of doing a pre-programmed 60 degree corner.
Or maintaining level flight, or any of the other things some seem to fear.

  Agreed. The problem is that those very same rules DO permit a pre-programmed corner, and that is very likely to get fixed in the very near future. If you don't want FBW to get caught up in that, then you need to come up with a reasonable rule that permits one and not the other. Personally, saying it isn't an autopilot is probably OK with me but that's not going to be good enough for everyone else, you are going to have to prove it somehow.

   Brett

Yes, it would.  It would take MEMS sensors, now readily available, and the specialized knowledge of control systems, with its kinda esoteric math.  Some of us have the latter, including Brett, me, Igor, and Tim.  I think most of us can see what's coming.

I'm not sure that the current crop of consumer-grade, lightweight MEMS sensors is up to the task of doing an entire pattern autonomously -- but that's mostly because there's very little information available to the Kalman filter about the airplane altitude until it pops into the first corner of the wingover.  After that, I'm pretty sure you could just attach the handle to a speed pole, then sit down and enjoy the show.

With GPS augmentation it would be a no-brainer, in a corporate-funded half a man-year of effort sort of way.  I've got about 50% of the code for that sitting on my computer, left over from a vehicle tracking project that included some generous terms about what technology I could keep for my own use.  Attach handle to speed pole, push "start" button, sit back...

And Howard -- I don't think the math is kinda esoteric.

   You aren't going to do a full pattern on inertial guidance with the current MEMs types that would fit in an airplane without an external observer of some sort. the drift and scale factor with 360-degree-per-second maneuver over 6 minutes.

I've started up a new thread for this:

http://stunthanger.com/smf/index.php?topic=32691.0