LibrePilot Forum
Users => Vehicles - MultiRotors => Topic started by: jtrout19 on March 13, 2016, 04:58:07 am
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So the first flight after starting over was today. She flew nicely. The only thing i had a complaint about would be that if i let go off the sticks she wouldnt stay and hover in one spot.
That being said. What next? With all the advanced stuff in GCS where do i go next. I would really like to be able to let go and it truly hold its position. What can accomplish that? Which advamce settings do you guys suggest learning first? What is the best way to learn? Thanks!
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Some kind of advanced GPS. But that's way beyond what I know about LP and the GCS. Without that it won't hover in one place it will always drift around a little. To have that locked in one spot hover it's needs GPS and a good tune would do wonders.
The best way to learn is do as much research as possible. About tuning in other copter forums and on YouTube. Once you start adjusting numbers and kind of get an idea of what the changes do and how your copter reacts then you will be on the right track. Just do as much research as you can and start tuning and really dialing in your copter. It's hard to explain and easier to understand if you see it in video
"Video Aerial systems". That's I B crazy. And he has a few great videos on tuning and what to look for. And Joshua Bardwell is a great tuner of clean flight and beta flight and has some great tuning tips and what to look for and all that. Although he is tuning in clean flight the end goal is the same. PIDs are PIDS. Just the numbers and the amount you change them is different. Both on YouTube
Ive have seen a couple OP tuning videos on YouTube and they also give you ideas of what to look for while tuning and how to adjust. Time for YouTube college
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My recommendation would be:
- Start with Complementary attitude estimation
- Get stabilization PIDs well tuned using EasyTune or TxPID
- Get altitude-vario/altitude-hold working, good vertical PIDs (be familiar with accuracy of baro sensor)
- Get good external barometer calibration, made outdoors over oplink, far from metal objects
- Only now when Baro, Magnetometer, GPS are giving good data, try INS31 attitude estimation algorithm. Mag and GPS must be green all the time, no jumping to orange, if it jumps to orange go back to first step and check whats wrong. It must be outdoors. Also there should be no oscillations in Scopes witch usually indicate problem with Mag readouts, maybe high currents etc..
- Be sure your GPS have updated almanac before first flight, that is done by exposing it to a clear sky for ~15min. Super capacitors in those modules last only 5-6h, you don't need it to collected sats before every flight within that time window.
Research topic, Wiki is a great source of information https://librepilot.atlassian.net/wiki/display/LPDOC/User+Manual
There are important must known facts which should not be ignored:
- None of sensors alone are accurate to hold your aircraft in a position (example baro 0.5m, gps 2m error). Only all sensors working together with proper setup (example baro covered with foam) and calibration are able to deliver good accuracy.
- None of sensors, no matter how set up or calibrated will give good results if your control loops (PIDs) are lousy.
- When you want to use GPS and switch to INS31, you are not adding just GPS as sensor. All sensors are used in that mode.
In short, no chances it will fly any better in INS31 with GPS, if it didn't fly already really good in Complementary. Usually is the opposite.
I hope that helps and will save you a lot of time :)
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Thanks guys. I will be learning as much as I can. I saw a guy flying one of those 1000 dollar quads the other day and he had it about 200 foot in the air and it was just sitting there totally locked in. It got me motivated to get that done with mine. I know i am a ways off. Hell i cant even get my oplink working. But i am going to remedy thay by just buying a new revo and oplink. Thanks again guys i will keep everyone updated
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I saw a guy flying one of those 1000 dollar quads the other day and he had it about 200 foot in the air and it was just sitting there totally locked in. It got me motivated to get that done with mine.
I am not saying that's impossible, just that it's not served on the plate because every build is so much different.
This movie shows GPS-assist for actually challenging setup of small copters, because mag is closer to ESC and power-lines and smaller are "usually" way faster than big builds https://www.youtube.com/watch?v=jAbNty8siac
or slightly bigger ~250mm copter position hold
https://www.youtube.com/watch?v=03t_RqmJHsQ
or this
https://www.youtube.com/watch?v=9aCUt8MUrMo
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So in Those two videos the quads are not vary stable in one place. So what is it about the high dollar quads that stick to a spot better than these two?
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So ive been doing some reading. I cannot get the revo to pick up any of my pots. I have opentx on my 9x. I want to use TxPID and it seems POTs are the easiest to use here.
Also the fact that my oplink is not working how will i be able to see oscillations. I understand what an oscillation is when decribing a waveform. But what oscillates on quads? When using TxPID do the settings automatic save when you change them on pots or do you have to plug it back back into pc amd save them that way?
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Those aren't the best videos to showcase position hold.
The first quad is a very tiny 150 size quad that weighs 7 ounces. Not knowing much else about it there's no way to tell how it's setup or any other details. And with a tiny quad like that it doesn't take much to move it around.
The second video makes more sense if you saw it where it was originally posted. He was responding to someone asking whether or not position hold works and just went outside and shot a quick video. The original posting mentions that it was a very windy day and that was why it was moving around so much. The quick camera swing to the bush on the left around the 50 second mark was to show how much it was moving.
The thousand dollar quads tend to be big, relatively heavy quads and that makes them less likely to get pushed out of position by small wind gusts. And because they make a lot of identical quads they have time to refine the settings to work as well as possible. Our quads tend to be one off builds that we can't just copy the settings from someone else and get it to work perfect right away. And I kind of prefer it that way, half (most?) of the fun is building it and tinkering with it to get it to work better.
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Does anyone know how to get the REVO to recognize the POTS on my 9X. I am using OPENTX and I cannot get them to work. So frustrated right now its unbelievable
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Configure you radio and affect pot to one Rc output/channel
Redo Transmitter wizard and move your pot when asked: AccessoryX you want
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Well I know what is happening now. So the revo has enough wired to accept 6 channels from my receiver. My Receiver has 8 outputs. The other two pots are on channel 7 and 8. How can I get the revo to read them without affecting my other channels
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When using TxPID do the settings automatic save when you change them on pots or do you have to plug it back back into pc amd save them that way?
This may help https://librepilot.atlassian.net/wiki/display/LPDOC/TxPID
Well I know what is happening now. So the revo has enough wired to accept 6 channels from my receiver. My Receiver has 8 outputs. The other two pots are on channel 7 and 8. How can I get the revo to read them without affecting my other channels
I suggest checking wiki about other options of connecting receiver https://librepilot.atlassian.net/wiki/display/LPDOC/Revolution+Configuration
The string you want to search for is "PPM Input ch1-12" it will find an entry in a table with all options you can configure receiver port.
Wiki is your friend ;) Someone had put a lot of time in writing it:)
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Awesome I will go check it out now thanks
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OK so doing some reading on the provided pages and on the equipment I have I have learned that my FrSky V8FR-ii Receiver does not support PPM only PWM. So My options 1. Get a new receiver. I was considering the FrSky D8R-XP which outputs CPPM or 2. Get a Signal Converter. So what would you guys do.
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Why a big receiver ? Try a D4R-II :)
(http://www.hobbyking.com/hobbyking/store/catalog/24788.jpg)
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Well cause eventually I want to put some other things on my quad and be able to control them with my transmitter. And for a little more I can get more channels. That being said. I did just take this thing out and flew it. It takes alot to make it stay in one place. A little jerky and it like to move by itself. Can you tune these without TxPID or OPlink?
I answered my own questions I am tuning it currently in my living room. The P slider under Roll always reverts back to 30 though. The other sliders save fine but that slider will not stay where I put it. Any Ideas On that?
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Can you tune these without TxPID or OPlink?
Yes, try, land, try, land, try... and half day later it can be done maybe, with try and error.
The small D4R receiver do the same as the big, it can output all the channels you need with PPM.
If you want to connect other stuff, you can control buzzer or gimbal through the board.
https://librepilot.atlassian.net/wiki/display/LPDOC/Adding+a+buzzer+to+Multirotor+frame
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awesome well I might have to pick one of those up then. Do you guys recommend tuning this thing in the basic tab or advanced tab. I feel like I am going to end up using the advance tab anyway so why not learn it now. I also can only find tuning info based around TxPID or easy tune. You guys know of any documentation on doing it the way im doing it?
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It takes alot to make it stay in one place.
Pure motionless hovering happens to be one of the most difficult things to do. The aircraft drifts with the air which is -always- in motion.
A little jerky and it like to move by itself.
Jerky when -you- give it commands, or by itself? If by your command then add expo. Or use more finesse to give smaller smoother motions to the sticks.
Can you tune these without TxPID or OPlink?
Tune 'what? Hovering? As has been mentioned only GPS can do that.
Tuning generally refers to 'motion' flying not standing still.
I answered my own questions I am tuning it currently in my living room.
Is this related to the above where you said 'takes alot to make it stay in one place?' If yes then indoors the quad will *NEVER* hover properly easily. The downwards air blast from the props hits the floor, travels across to the walls, slides up the walls to the ceiling, and travels to the center where it turns downward to feed the props more air. The quad creates its own turbulence. :) There's even a 'wall magnet' effect where the closer you get to a wall it feels like the wall is sucking it in. That's related to the outdoor 'tree magnet' effect which is a -real- aerodynamic effect. Air is a fluid medium whose motion we can't see but can see and feel the effects.
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awesome well I might have to pick one of those up then. Do you guys recommend tuning this thing in the basic tab or advanced tab.
The basic tab gives a graphical representation of the PI numbers, plus the numbers, and leaves off the D. The advanced tab is just the numbers and includes D. There's more added too but those are what we work with mostly.
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Thats kinda what I thought. Kinda threw me off with the advanced having values in decimal and the basic tab having whole numbers.
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So the first flight after starting over was today. She flew nicely. The only thing i had a complaint about would be that if i let go off the sticks she wouldnt stay and hover in one spot.
This can be used to correct drift:
GCS -> Configuration -> Attitude -> Settings -> Rotate Virtual
drift left needs + on roll
drift fwd needs + on pitch
make an estimate of how many degrees it is wrong... or just try 3 in the direction you need for first try
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Jerky in flight can be vibration issues:
#1 balance props
#2 balance props and motors
#3 balance props and motors and look for loose screws or broken parts (get the idea? :) )
#4 increase the gyro vibration filter on the GCS -> Configuration -> Stabilization -> Expert page
#5 increase the accel vibration filter on the GCS -> Configuration -> Attitude -> Settings page
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Awesome Thanks guys I will definitely check those things out. I did balance my props really well before I put them on. I didnt balance the motors though. Never done that before. I will say I have my FPV camera zip tied and there is no shake or vibration to the image as far as I can see. I know there still could be vibration.
On a side note. I have a battery drop really low in voltage today out of the middle of nowhere and I believe it killed my OSD. I had to reprogram everything after it happened as well. But I it is like my OSD is totally dead. Wont display anything. Can't get my FTDI to connect to it. Just thought I would let you guys know.