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  • Reman: Like I said, In the past I've had a handful of packs "Go off" at me like fireworks after bad crashes (Usually with RC helis), So it's hard to get that image out of your head while stripping down Li-Po's. :)
    Today at 11:22:54
  • shawdreamer: the horror stories will always incite worry when messing about with Lipo's but its the same as everything else when working on electronics alike, alsong as your careful and methodical there's very little to panic about, I regularly recycle 4s's with a single dead cell into usable 3s packs, end of the days its alot more economical, safer and enviro friendly than having to bin them....just a pain that the dead cell is NEVER one of the outer cells so you always end up having to strip a good cell off to get at the bad cell before putting it back afterwards, its like dropping toast, it'll always land buttered side down and inevitably covered in pet fur :angry:
    Today at 00:11:16
  • Reman: Just did the one electrical job that still scares me. I dismantled some Lipo's with knacked cells and built usable packs out of the good cells. I've had packs go "VOOOOOOSH" at me in the past so I'm always slightly scared of having bare lipo contacts anywhere near what I'm working on, But all appears to have gone well and one of them is currently doing a charge/discharge cycle to make sure nothings a miss. :)
    January 20, 2019, 22:28:43
  • Reman: My original Dremel Pro made it to 14 years of heavy weekend use (And abuse) before it crocked. Dismantled that but it turned out to be a "Control module" fault, And Dremel made it ni on impossible to get into that without pooching it completely. :(
    January 20, 2019, 22:17:27
  • ched999uk: BR  ::)
    January 16, 2019, 22:26:54
  • Bad Raven: That's a warrnty claim if ever I heard one....
    January 16, 2019, 20:32:55
  • ched999uk: My 28 year old 12v 35w Weller soldering iron failed  :( I didn't fancy forking out £100 for a new one. Stripped it down and found conductor snapped in cable. 10Mins later all back working great. :smiley: ::) I am very happy!!
    January 16, 2019, 17:23:06
  • shawdreamer: "look up there....its a drone!.....and whats this noise?..... no.....no..... it cant be!....NOOOOOOOO.......OOOOOOOOOOOOOPS I DID IT AGAIN, I PLAYED WITH YOUR HEAR....."
    January 10, 2019, 14:17:24
  • shawdreamer: <starts downloading britney spears albums and preping his large frame to carry a PA system>
    January 10, 2019, 14:15:08
  • Bajadre: defo steveo :) we should get loads of drones together up there so how they handle more that one lol
    January 08, 2019, 19:39:07
  • steveo9007: its all a ploy to get who ever has won the contract for geofencing the airport in, i reckon  ::)
    January 08, 2019, 18:38:26
  • Bajadre: more lies hope they prepped the police staement already lol
    January 08, 2019, 18:27:49
  • Bad Raven: Take Offs resumed
    January 08, 2019, 18:24:45
  • steveo9007: yeah not good though is it..what will come out of this now its happened at both major airports  :o
    January 08, 2019, 18:05:13
  • Bad Raven: Planes still landing, appears take offs affected
    January 08, 2019, 18:02:47
  • steveo9007: newsflash people, drone sighting at Heathrow Airport  just received on news app..
    January 08, 2019, 17:54:07
  • shawdreamer: tsk x2, just checked my thingiverse messages too... another a8 owner asking if one of my designs would work with his printer.... I said no as its not fire proof.... now he seems confused :confused:
    January 05, 2019, 15:35:09
  • hoverfly: Some people,  he's probably heading for a Darwin award... :laugh:
    January 05, 2019, 13:58:53
  • shawdreamer: tsk.... a new Anet A8 owner asking for mod suggestions for his xmas first printer on thingiverse... I suggested a fire suppression system or atleast a wall mount for a fire extinguisher and smoke alarm..... he removed my post.... no helping some people :shrug:
    January 05, 2019, 12:42:05
  • Reman: I did double check it with a metre (Mainly because I knew if I didn't check the polarity this would be the time the manufacturer had gone off script and put the negative in the middle of the coax) and felt slightly cheated because it was only making 19.7 volts. :)
    January 04, 2019, 14:01:11

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Author Topic: Hexacopter is difficult to fly  (Read 208 times)

Offline sirch

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Hexacopter is difficult to fly
« on: November 04, 2018, 14:16:47 »
I'm new to the self-build game and have built myself a hexacopter on a Tarot 680 frame, so it's a bit of a beast. I am using a Pixhawk 4 flight controller but it is difficult to fly and I am wondering if this is normal or if I haven't got it set up correctly. I have only flown it a few times and have wrecked several props and the undercarriage, it seems incredibly difficult to land, it is either hurtling up in the air or crashing into the ground, there doesn't seem to be much in between. I have been launching it in stabilised mode and have once got it into hold/loiter which worked fine. It also yaws/spins at any opportunity. Is it possible to change the scaling on the sticks to make them less sensitive? Or do I just need a lot more flying practice?

Offline ched999uk

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Re: Hexacopter is difficult to fly
« Reply #1 on: November 04, 2018, 14:40:36 »
:welcome:
I found the bigger the quad the easier it was to fly as it responds slower.
I assume you have done basic checks like motors and props spinning in correct directions on all arms?
I assume you are flying in a stabilised mode? If not fly in a stabilised mode as acro/rate mode is very difficult to fly.
I assume that you have calibrated the esc, setup the receiver to the correct ranges (1000 = low 1500 = middle 2000 = hi).
How did you setup the PIDs? PIDs might be way off which could be hampering your flights or tx rates. Rates are a sort of scaling of your sticks, you can put in a curve that makes the sticks less sensitive in the middle and very sensitive at the ends (not sure on Pixhawk but that's how Betaflight works).

I found using a computer simulator was good for getting my fingers better able to make the small movements you need on the sticks. I use FPVFreerider and Velocidrone with my tx plugged into a laptop. They are both more for acro/rate fpv flying but they might help getting your fingers working better? FPVFreerider has a free version (full only about £8) that you can try. Josh Bardwell has a good series on youtube using FPVFreerider to learn to fly, this will be in acro/rate mode though but FPVFreerider does do stabilised mode.

So good luck, keep us posted and any picys of your 680?

Offline sirch

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Re: Hexacopter is difficult to fly
« Reply #2 on: November 04, 2018, 15:36:20 »
Thanks for the reply ched999uk, yes it's in stabilised mode and I have checked all the prop rotations many times, it actually gets of the ground OK but then shoots skywards an yaws/rotates and is hard to get back to correct orientation.

This -  https://docs.px4.io/en/config_mc/pid_tuning_guide_multicopter.html suggests that the default PIDs should be OK so I haven't done any set up for them.

I'll try the simulator software and see if that is similar in handling to the real thing


This thread is where it all began

Here's a photo of it early in the build
IMG_0544.jpgHexacopter is difficult to fly

Offline ched999uk

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Re: Hexacopter is difficult to fly
« Reply #3 on: November 04, 2018, 16:16:27 »
I remember the thread  :smiley:
If it's zooming off and yawing that suggests that maybe it needs calibrating. I have not used a Pixhawk but normally you need to calibrate all esc, calibrate tx to rx to FC (Pixhawk), calibrate the accelerometers and make sure gps is set correctly.

The sim will not be similar in handling in any way to your t680 but it might help your fingers get used to small movements needed.

Offline sirch

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Re: Hexacopter is difficult to fly
« Reply #4 on: November 04, 2018, 18:36:40 »
Yeah, done all that calibrating several times, it didn't make any difference. Hopefully since this is in the PixHawk thread someone will be along to share expereince.

Offline UrbanFPV

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Re: Hexacopter is difficult to fly
« Reply #5 on: November 04, 2018, 18:37:08 »
With Pixhawk, you will need to calibrate all sensors in the sensors page on QGroundControl.  But normally it won't let you arm if they're not calibrated.

Check the mixer is right for the Hex ie: Hex + or X mixer.

https://docs.px4.io/en/airframes/airframe_reference.html

Yawing suggests a magnetometer issue.  There have been magnetometer initialization issues with particular pixhawk boards (PixMini).

I presume you're using PX4/Dronecode firmware as opposed to Ardupilot?

I've not had a problem setting up quads or fixed wing with Pixhawk, but did have issues trying to get a Coax Octo to fly correctly which I'm sure was down to the mixer not being right for the setup.

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Offline sirch

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Re: Hexacopter is difficult to fly
« Reply #6 on: November 04, 2018, 19:20:28 »
I'm fairly sure I've got PX4 firmware but I'll check and I know I have X hexacopter frame set up correctly.

The thing is that it flies, lioters, etc it is just massively sensitive, breathe on the sticks and zings of in one direction or another, it's like the sticks could do with being 5 times less sensitive.

Offline ched999uk

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Re: Hexacopter is difficult to fly
« Reply #7 on: November 04, 2018, 20:48:22 »
It's always worth running al calibrations again when you have issues as sometimes they have not saved properly.

Just having a look at the documentation and I found this : https://docs.px4.io/en/advanced_config/parameter_reference.html
Look at MPC_XY_MAN_EXPO and MPC_YAW_EXPO. They seem to be setting to give a bit of exponential curve to the controls. This link isnt anything about px4 but it shows what an exponential curve is https://oscarliang.com/rc-roll-pitch-yaw-rate-cleanflight/
I am surprised that there is not an easier way, maybe there is?
As I said I have NO experience with px4 or any Pixhawk  Flight Controllers.

Hope that gives you some ideas?


Offline sirch

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Re: Hexacopter is difficult to fly
« Reply #8 on: November 12, 2018, 21:40:49 »
Friday was the first time I have had to have another go with the drone. I have reinstalled the firmware and gone through all the calibrations, etc. again but perhaps the biggest change (or most likely to have had an effect) is to set some curves (expo) for the sticks on the transmitter. As mentioned above it all just felt to sensitive and I set some pretty dramatic curves reduces that sensitivity.

So after charging the batteries, and doing final checks it was into the garden to give it a go




The fact that I could fly it with one hand and video it with the other speaks for itself  :smiley: