Understanding PIDS in Quads
For two years I have wrestled with Multiwii and Arduino based quads.
When you get it right it's great but when the PIDS need tweaking it's bubble bubble, double trouble.
Can anyone explain to an old Newbie how to get smooth flight out of PIDS ?:confused:
I am waiting for the answer as well.
I think I sorted my quad out tonight ready to try tomorrow.
It got the wobbles and crashed each time I took off.
I have reduced the P gains dramatically and I gain quite a lot and it seems very steady now.
I am learning fast. It depends on the size of your quad a lot. Each one is different so you really need an experienced person to help. I have to do it on my own but I learn fast. I am using the KK2.1 FC board on a 550 Hobby King Quad. I found a good way to check the flight reactions 'on the bench' and then changed PIDs but it is quite dangerous and I wouldn't recommend it.
I have a friend with Arduino and KK2 boards and he mainly flies the KK2 as the Arduino is too much hassle.
Why don't you, for the sake of $30 try a KK2.1 FC Board. Maybe your struggles may end. At least you can change your settings without a computer in just a couple of minutes.
Yes, I am an old newbie too.
Understanding PIDS in Quads
Have you checked the new controller from headsup hobby? I forget the name if it, but I beleive it works just like a naza. Almost the same software also. I am very pleased with my naza lite as I have a very stable av platform now.
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I see in your other thread you are happy with your Walkera Pete so my response is probably irrelevant now.
PS Headsup Hobby don't ship to Australia tarheal63.
Go NAZA.....problem solved!
PID's and flight controllers.
I don't disagree with those who love the NAZA but after enjoying so much flying with Whitespy, KK2.1 and Bambucopter it is a little hard to put it at the top of the list. I have never needed to make any adjustment to the settings of a Whitespy or a Bambucopter except when the model was very tiny.
And it is in those cases that I love the KK2.1. (this week offered for $15.00) It is such a pleasure to stay at the field and dial in small adjustments without needing USB patches and laptop. You make the adjustment, re-launch and you know if it's getting better or worse. That ease of operation encourages you to do things one step at a time.
I know a lot of people say only ever adjust the P but these things are in a loop and it usually ends up with smaller variations (in the same direction) of the I and D.
But I still would like to see a handbook where the symptoms are shown in relation to the correction made.
I have never taken the P over 4 and most times I get satisfaction around 2.8.
People tell me that vibration is the big issue but while I do balance the props I have never yet added a balance weight to a motor. My fleet now includes 15 flying Quads with six different flight controllers. You are allowed to tell me I am mad but you should know I have a certificate. I got it at birth.:D
I wouldn't say "your'e mad" Pete......I'd say your'e informed, like to tinker and have the patience of a saint....
After having myself spent endless hours dailing in various gyro, stabilization sensitive controller units on variuos sizes of CCP heli's for a few years, and with the advent of all the "newer" more techo advanced stabilization (return to home) units related to quad and other multi rotor craft.......I finally just decided to keep things as simple as possible and spend more time actually flying....rather than hours dialing settings in after every flight and spending more $$$ trying out systems that require external firmware updates and frequent monitoring.... Thus, my taste for the "little" more expensive, but solid and predictable NAZA equipment....... I only own two quads and have no intentions of flying FPV/UAV.........but I appreciate the ability and freedom of being able to if the day ever comes without needing to add more equipment and software to my existing systems.
I'm not familar with the Whitespy or Bambu, but have buddies with the KK2.1......it's good stuff if you keep it up-dated after modifying ones equipment........I jumped on NAZA mainly because I know many who use it and it's logic seems to work for my way of translating things.....I'm not really in a position to rate it #1 or #10.....it just works great and has been an easy confiquration transistion for me......and I spend less time "tinker" with the settings and more time enjoying my flights.....;).....and the fact that I finally converted over to the Spektrum TX/RX stuff which is seemless with NAZA.
A very doubtful Saint
But it's a fine compliment. My gospel is fun. Anyone who is having fun will be happy with their lot and I will be happy for them. The Whitespy range is very interesting. There is a $15 board called the flip and for straight out fun with quads or tri's it is very hard to beat for value. I think I have five of them and have friends with them and have never had any quibbles in conventional size machines. For Multi wii users with access to a GUI they are easy to fine tune in micro size models. They are good in that format as the board is only 32mm sq. Whitespy is found via Ready to go quads. Paul Baxter who runs it has a good range and part of my home sickness relates to a Hot new board with a deluxe GPS on it, which was in my mail box as I drove out. His site has a lot of set up information and with some experience you will be able to work your way through any of his projects. The Flip is absolutely plug and play if that's what you want. You do need to nominate what configuration (plus or times or tri) and you can save a dollar or two if you are happy to solder on the pins which he supplies. One tip with the flip. Take a picture of the underside of the board and file it on the desktop. I guess you know why I suggest that.
Today I learned the secret of the RTH which waits for failsafe. It is so easy. Turn the transmitter OFF !!!:D Not for this old bloke but I am sure it works.
A word of caution about GPS Failsafe modes.
Some manufacturers do advise against switching the transmitter off during GPS operations. Check your manual, if of course it is readable. :)
I don't really like flying the Naza-M Lite I've got... it's relegated to AP duties on my 550 and it doesn't have enough options for me.
I've been flying an Armattan CF 355 with a Naze Acro board and it's a BLAST, but a bit more complicated to set up. Fastest autolevel I've ever seen though, and the Horizon mode (aerobatic with autolevel) is amazingly good. It'll even come out of a suicide.
His quads (and tricopters) are getting popular so I don't know how long he'll be able to keep up that level of service, but for right now they're awesome.
He sells the frames alone, DIY kits with all the parts for you to build it yourself, or RxR (receiver ready). My carbon fiber 355mm quad was $270 with the Naze Afro Acro board (which I mentioned earlier) plus shipping.
He has several different models and from what I've heard they're all excellent... but I'd highly recommend carbon fiber. One customer's 258mm quad crashed in a road and was run over by 6 cars... and the frame just had some scratches on it (everything else was destroyed, obviously).
I'm not affiliated at all with Armattan, but I'm VERY impressed with the level of quality and service. I'm planning on ordering at least two more from him.
ETA: I've never ordered from Witespy (I think that's who you were talking about?) but he's also a one-man operation I believe and lately I've heard he's swamped, so orders are taking a long time to go out. Not sure how true it is, but it's kept me from ordering though I need some stuff.
A new twist in the road.
I am steadily advancing with my latest in the open source control systems, The Pixhawk PX4. I have not been blessed in my earlier versions and I wasn't today. Grab a cup of coffee and I'll tell you the tale.
In this latest Pixhawk PX4, the designers have abandoned the PIDs tuning system where the user has a chart (in Mission Planner) and enters new values for P I and D. I did not know that before I bought it.
They have put in its place, an auto-tune system which analyses the flight and makes adjustments. I am guessing that this is seen as a safer option but I very much doubt the quality of that thinking. With a chart system the careful modeler will eventually solve the problems but an impatient modeler wont
I have flown auto-tuners before with great success so I was not really worried by this change. But this one is seriously different! This one does its work very slowly. On line I noted the advice that it might take 8 minutes. Now that is quite a challenge for those flying with 2.2 ah batteries.
The plan is to fly a tuning flight in very light winds in a fairly clear area. I went to my 200m square field with what seemed like nil wind. I had preset the satellites at home and walked the model to the field with a battery maintaining the preset. When I disconnected from the computer I had seen an HDOP of .88 which was based on ten satellites. It looked good. At the field I changed batteries to one which had delivered seven (tested) minutes the night before. It took another two minutes before the controller was happy again with satellite coverage (HDOP then unknown but flyable).
It was time to go and I launched. The plan suggests that you fly to a safe height (in my case 5 metres) and switch to altitude hold. I did that but noticed that at five metres there was a cross wind and the drift was significant. I flew the model directly upwind of my position but suddenly remembered that I had not plugged in my battery checker. So I switched out of alt hold and landed. plugged in the checker, reset the timer (silly mistake) and launched again.
This time everything went super smoothly. The model not only held altitude; it did not move from the switch spot where I applied the autotune command. (It could be that in auto-tune, with a really good HDOP, the contoller adds loiter to its navigation)
The tuner was clearly doing its job. It seems to test roll pitch and yaw (in that order) with each elapsing minute. My transmitter timer was faithfully telling me the minutes and I heard 5. But before 6 my battery checker was sounding the alarm. The rule is LAND. I knew the autotune had not finished but I guessed it must be close to finishing so I delayed by, maybe, twenty seconds.
Twenty seconds too long. It dropped like a stone but not quite flat. A propeller broke and that motor mount broke free (as it is supposed to do in a crash). The timer showed 6 minutes 10 seconds but it was failing to include the first flight time as I had reset the clock. The lesson learned is that you must have more than 7 minutes in the bank and must not reset the clock.
I must now wait for light winds again and repeat the exercise with 4.4ah.
If I thought that the design team was listening: I would say that an 8 minute auto-tune does not fit the market. If that total time span really is essential, then the Controller should memorise its progress in tuning, so that the complete tune can be achieved in more than one flight with multiple batteries, if required. If safety is the reason for auto-tuning that seems like a small and safer concession.
I am sure you will have heard a lot of nonsense about clones in this market. The design is Open Source. Any manufacturer can make it! Not all of them will apply the same quality controls.
That is why I suggest that we stop calling these devices by their design names. The critical name is that of the manufacturer. In my case it is a BZUAV and at every stage of installation it has behaved impeccably. I have no doubt at all that; when the Pids are rationalised it will work well. If it fails to meet my expectations you will hear about it.
Finally I must say that I enjoy these challenges !!!:D
If you are getting as much fun from some other device which was fully developed when it arrived in its big expensive box and flew perfectly on minute five, of day one; I am happy for you !!! :D
I love what I have and, more importantly, I treasure what I have learned in the process.:D
Better than I thought.
Later in the day (yesterday) the repaired Quad was back in the sky and at first I thought it was smoother. Wishful thinking on my part. The test was to see what duration I could achieve with two 2.2ah batteries. I also wanted to see how it would handle the increased weight. No problems on the weight front and the flight duration was up to twelve minutes. Great.:D
But more research on the net led me to a site where it was said that there is a special tuning sequence in Mission Planner's Standard Param's (Bit-mask) which allows the user to select a single function to tune at a time. (In theory it will take much less than 8 minutes) I will try that on the pitch axis which remains erratic.
It won't happen today as the wind will be too strong but I have fitted 9 inch props and will check duration.
Despite, or because of, the wind.
I have been forced to look more closely at Mission Planner. The You tube items show an earlier version with a PIDs chart as was used for the APM series.
There are manually entered P and I facilities in Mission Planners Standard Params. The list is so enormous that I got tired and failed to see them.
The easy way is to go to the search box and enter the word Roll. The search result will present all the items related to Roll. You will quickly find that there is a P adjustment page for Roll and others for Pitch and Yaw. I moved the sliders for each to about 60%. (they had been set at about 20%) It is almost perfect now. A few more finer adjustments will almost certainly get it as I would want it. I have not sighted a D adjustment yet. It could still be there.
I have enjoyed reading your saga and share you pain. I have used APM and MultiWii on several rigs and finding the right parameter (and adjusting it the correct direction) has been an adventure. One thing that has helped is a 3DR radio link to my ground station. Fly a little make an adjustment and get back in the air to check it out. I used to use a computer but now use a tablet with EZGUI for multiWii. I am sure that there is one for APM.
When you talked about autotune It reminded me of BradWii. This was the first (that I know) autotune sketch. Loaded it on a pocket quad and hit the switch. I couldn't keep the quad in the air or in close enough to see or stop laughing long enough to get it to work. Figured it out after a while. Keep trying you will get it.
My NAZA systems actually taught me more about flight tuning as my adjustments usually made them fly worse and they can do inflight tuning so you can see what increasing or decreasing a setting actually does in the air .
Keep learning and try to have fun.
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