LibrePilot Forum
Users => Vehicles - MultiRotors => Topic started by: Bobdudeman1988 on February 15, 2016, 02:39:03 pm
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Hello major newb here my name is Rob. i just got done building a totem q330 quad and just had it out for a few flights. im having a problem when going beyond 50% throttle it shakes pretty bad. ive adjusted my pids a little here and there but i cant seem to dial it out. i just enabled tpa and have yet to fly it. but i wanted to see if im on the right track. as ive said. the current settings i havent tried yet. i lowered the p and i 7 down and enabled tpa.
its a totemq330
sunnysky 2207 2100kv motors ZTW SPIDER PRO 20A ESC blheli 6x4.5 props 4s 1800mah battery fsi6 transmitter flying in attitude mode.
pictures of my pid settings. my quad. and a link to my first attempt at fpv. shows the shaking problems....thanks guys!
(http://s8.postimg.org/oqfdlj8f5/20160214_183521.jpg) (http://postimg.org/image/oqfdlj8f5/)
(http://s8.postimg.org/x4v09m9gh/pids.jpg) (http://postimg.org/image/x4v09m9gh/)
https://www.youtube.com/watch?v=LzenOFM8MNU
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Yes I believe your on the right track. Tune pids till its smooth most of the time. Half throttle and below. Then Add TPA, which reduces the PID's at higher throttle to get rid of thoes high throttle shakes. Usual TPA activation point is around 1500 on the throttle, so about half. Example. TPA start at 1550 at 10% reduction in PID and at 1900 have it like 50% reduction and see how that flies. (If that makes sense) you may only need 20-30% reduction in PID at full throttle. So play with it. I've heard of some guys using TPA to increase PIDs like 10% at low throttle for flips and acro flying at low motor rpm. I'm not exactly expirenced in setting up TPA, but I believe you are on the right track. Look on google or the LP wiki for TPA examples if you get confused.
What does it do if you lower your P for pitch and roll below the 210 mark. Try like. .00190 for pitch and .00175-.00180 roll. With your quad being longer than wider(the body) it's will need a slightly higher pitch p gain than on roll. Lower your I a touch too. Come down .00020-.00030 on I with the gains too. Like 620 for roll and 630-640 for pitch. It looks like it fkys just fine except the shaking. To high P can cause the the high frequency occilating. Are these default PIDs?
If you like the way it flies control wise maybe just fiddle with the TPA first.
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no there not the stock pids. i picked a profile that that the same motors and props and went from there. however when i first tried with the factory pid it shook so bad on take off and flipped over and crashed. i lowered the p and i on roll and pitch till i got what you saw in the video. its been snowing all day and i haven't had a chance to try out the settings i just posted but there not to much different than what i had before aside tpa. ill try what you suggested when i get a chance.
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Being only a 330mm quad I wonder what the blackout or Emax tune would fly like. They both run a 6" prop. And might be a quick fix.
If you got to where you are from lowering PI on Pitch and roll I would say keep going a little more then tune TPA. You may not need it
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i tried a few profiles. all ended up the same. death flips. i feel like im almost there. im anxious for this shit weather to go away and i can start flying more. but untill the snow melts a bit im grounded :( ill report back when i have done more testing. thanks for your help!
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well i had some time to do a quick LOS test. with the settings i posted. pitch seams alright. but roll is twitchy and i think there is some high throttle twitches yet to but seams better. i do a full throttle punch toward the end and you hear my lipo buzzer sound. ill try lowering my roll gain a bit next.
here is video.(soon as its done processing...runcam2 files are huuuge)
https://www.youtube.com/watch?v=x5rzOXl0AyI&feature=youtu.be
https://youtu.be/x5rzOXl0AyI
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what c rating is your battery? I would say that high c rated battery is very important for quads. you got 4 times the amp draw compared to fixed wing Craft and even if your quad works fine with lower c your batterys will suffer
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Its an 1800mah 45c glacier battery from buddy rc. I figured max amp id draw is 80 amps full load and that battery fit the bill. My lipo alarm is just touchy. Likes to beep at 3.4 volts somtimes. When it goes flat dead its louder and beeps like mad
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Its an 1800mah 45c glacier battery from buddy rc. I figured max amp id draw is 80 amps full load and that battery fit the bill. My lipo alarm is just touchy. Likes to beep at 3.4 volts somtimes. When it goes flat dead its louder and beeps like mad
1800*45/1000 = 81 Amps max continuous current. If you determined that at full load it draws 80A it would be just right the battery limit, so makes sense. Or did you use more powerful battery while determining this ? I rarely fly battery till it's flat dead :) They don't last long that way.
This is pretty good calc http://www.ecalc.ch/xcoptercalc.php if you want to determine efficiency of your build.
Quad may also shake if it tries to spin up props but battery stalls, it may look like choking, at least mine did that when battery was low.
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im gonna try that calculator! and during this test the battery wasn't 100% full...like 80% and it was very cold outside. still it only does the beep after a full throttle punch...witch with this thing..isnt really necessary all the time :) edit: i just looked up some thrust test videos for my motors. looks like they pull 27 amps each at full load. so i might be overdoing it a bit. and my battery dont have a specified burst limit. my escs are burst rated for 30amps so i should be ok on that front. ill just avoid the uber punch outs all the time :)
ill get these battery's once im ready to start flying all the time
http://www.buddyrc.com/glacier-75c-1800mah-4s-14-8v-lipo-battery.html
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really necessary all the time :) edit: i just looked up some thrust test videos for my motors. looks like they pull 27 amps each at full load.
motors might be rated for certain power, but the current they draw depends on the surface of props and the speed, so if you put props with bigger surface they will draw more current (if battery allows and esc can stand it), decreasing flight time, but giving more punch. Although if you exceed electric power rating of motor (Volts * Amps your draw), the windings may melt due to higher temp, short and "blue smoke".
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i was always partial to magic smoke :) is there a for sure way to figure out what the max amp draw is on this thing? i know the motors can take it..but im concerned about the escs.
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well i had a 3rd test flight today and i think its pretty good. however due to wind i cant fly outside so i did a quick flight in the house. just to kinda show the settings the only thing im confused on is the inner and outter loop settings.. ive been matching them together but i dont know if thats right. still...flys pretty good.
here is the settings i used and a video.
https://www.youtube.com/watch?v=Vah4g2wUF-I&feature=youtu.be
https://youtu.be/Vah4g2wUF-I
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Inner loop is rate mode PID and outer loop is attitude PID
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But they do work together in addtiude mode. Im just curious is to how you set them.. Like i did mirroring the settings?
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They do work together in attitude. Although Im not clear how. And if you tune rate first you may not need to touch outer loop. Set inner loop in rate mode. Then seperately on the same settings bank just change the flight modes from rate rate rate manual to atti atti axislock manual. And if it twitches when it goes back to level when you give quick roll or pitch inputs lower outer loop P gain. And that usually about does it.
I don't think mirroring the settings is a thing. Tune them seperately. Innerloop First in rate mode. Then switch to attitude and just tune P for outer loop if it's bouncy when you move it. Just leave outer loop I at 0.
I think that's right. Maybe somebody more knowledgeable can correct me or back me up.
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Ive only been flying and tuning in addtiude mode..i tried rate once and it was very hard for a newb like me to fly. How does one tune rate only if you cant fly it yet lol. So you think i should set the outter loop I gain to zero?
It appears to be flying ok. But i never flew one before so i dont know what im missing
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Ive only been flying and tuning in addtiude mode..i tried rate once and it was very hard for a newb like me to fly. How does one tune rate only if you cant fly it yet lol. So you think i should set the outter loop I gain to zero?
It appears to be flying ok. But i never flew one before so i dont know what im missing
The LibrePilot uses dual loop controller for stabilization. That means that when you are in attitude stabilization mode for chosen axis, signal from your transmitter goes first to outer loop (attitude), there it is compared with gyro and send to inner loop (rate).
When you tune rate (inner) loop, while flying in attitude mode your whole system is tuned, and you don't need to tune outer loop.
If you are in rate stabilization mode, signal from transmitter goes directly to inner loop (bypassing outer loop and disregarding it's values). Signal is compared then directly with gyro and passes to control. By tuning in rate mode, you don't take into account the settings of outer loop.
I am a newbie here, but I failed miserably when I tried tuning outer-loop, but tuning inner loop did the job for me.
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It's hard to tune for rate if you can't fly in it. Bottom line....wait to tune rate mode
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The only thing i notice is when i roll left or right. It will auto level slower and still move in that direction for a bit.i think this is normal but as i said this is all new to me.ill get a video of it flying outside soon
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The problem with using someone else's settings is that little differences in hardware can make a big difference in PIDs.
I would suggest saving what you have so you can easily go back to it, and trying stock settings.
Another thing is that vibrations can cause problems. Make sure your props are balanced and track in the same plane (not an upper blade and a lower blade).
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my props are perfect shockingly. i saved it as of now but my settings still seam off. i was trying to set up txpid and i got one channel to work with one of my potenometers. but i got a fs i6 rx and one spare channel is controlling the flight mode. when i try to disable the flight mode to use ch.5 to control another txpid instance. it wont work. so it seams i can only do one at a time. im gonna try to tune it in rate with the speed on degree/second to 70. one factor at a time...you think i should just redo the wizard and use generic quad settings? i selected a profile that was similar in motors and props and frame size
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The first video seems to say that PIDs are probably about right, but are too high at high power.
TPS is the fix for that. It reduces PIDs at high power and increases them at low power (helps with wobbly descents).
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well i did save everything so i could go back worst case. :)
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well i got to txpid tunning today and this is the end result in rate mode with a slower response time..
i think its flying pretty good...next up to tune the outter loop for attitude mode.
video and picture of inner loop settings
https://www.youtube.com/watch?v=h8HrS-OkvLU&feature=youtu.be
https://youtu.be/h8HrS-OkvLU