Drifting problems / white LED

[Sebas600]

Hi guys,

So was out today for the first time in long time. finally some good weather for flying, 3m/s winds no gusts.

Set everything up, got gps, started the camera and opened the throttle(att), the MR started to wobble a lot(skids on ground) took off and it was stable when of the ground and then turned on gps.
The MR started to drift all over the place! White LED started flashing and could barely land it safely.
So I've had this white LED thing before but nothing really happened apart for it flashing.

I've bought the WKM because it should be a stable platform and with good gps lock.
Been working on this thing for some time now but it had never really been stable without manual corrections.
How can you best align all the stuff? IMU with the frame, IMU and GPS. It seems that there is a problem with the GPS unit to me but what can it be? I had the IMU and GPS closer to each other and that worked better. Now have it on a small pole as seen below. It is also shielded by coper plated PCB. The IMU is stuck with double tape with 0.5mm foam and is fixed securely, can't dance around.

Now going to update firmware to 5.02 to see if this has any effect.
View attachment 2333View attachment 2334View attachment 2335View attachment 2336View attachment 2337View attachment 2338View attachment 2339

Sebas

 

[lperagallo]

Hi,

It is best to be on the latest software version. So far the biggest issue I see is the position on the GPS receiver. It needs to be farther away from the IMU. It should be mounted using the longest rod supplied. That will help with GPS lock and signal processing. Did you calibrate the unit? You have a nice clean installation. Can you share your settings. I'd like to see your gains and position settings. Also, what were the weather conditions. Did you take it from a warm to a cold environment? The IMU needs to adjust to the temperature before taking off. What you describe is a condition of going from a warm to cold environment.

The white flash is OK if it is occasional. If it happens frequently then you may have vibration the unit can't handle. Did you balance your props?

Please post screen shots of your settings and I'll take a look at them.

Lou

 

[BorisS]

Sebas600,

i was taking my CX out on some harsh conditions lately !

I have notice the more wind outer influence to the IMU the more the WKM regulates obviously, again affecting the IMU ! Really check your setup if there it any play concerning your IMU. Mount it dead solid use additional cable straps to get it even more solid. Since you have a mounting plate on your centerplate also check that, that is doesnt have any play. If you pick your copter up only hands on the mounting plate is there a solid connection between it and the frame. My experience the more solid the IMU is attached to the frame the higher you can go with your gains in the wind with out getting oscillations. The benefit of the higher gains again its holding it position better in the wind.

Boris

 

[Sebas600]

Hi,

It is best to be on the latest software version. So far the biggest issue I see is the position on the GPS receiver. It needs to be farther away from the IMU. It should be mounted using the longest rod supplied. That will help with GPS lock and signal processing. Did you calibrate the unit? You have a nice clean installation. Can you share your settings. I'd like to see your gains and position settings. Also, what were the weather conditions. Did you take it from a warm to a cold environment? The IMU needs to adjust to the temperature before taking off. What you describe is a condition of going from a warm to cold environment.

The white flash is OK if it is occasional. If it happens frequently then you may have vibration the unit can't handle. Did you balance your props?

Please post screen shots of your settings and I'll take a look at them.

Lou

- I've just installed the latest version.
- I will get the GPS unit higher.
- Did not calibrate the "unit"???
- my settings are:

View attachment 2340View attachment 2341View attachment 2342View attachment 2343View attachment 2344View attachment 2345

- The weather was fine, I always check with a helium balloon.
- The MR was in my storage, around 14-15C and took it out to my car 10C and then outside 5C (lipos where at 20C)
- Props are brand new and balanced graupner E 11x5 on AXI 2814/22
- Turnigy plush 40A timing medium
- 2x Zippy 5S 4000MAH paralel

 

[Sebas600]

Sebas600,

i was taking my CX out on some harsh conditions lately !

I have notice the more wind outer influence to the IMU the more the WKM regulates obviously, again affecting the IMU ! Really check your setup if there it any play concerning your IMU. Mount it dead solid use additional cable straps to get it even more solid. Since you have a mounting plate on your centerplate also check that, that is doesnt have any play. If you pick your copter up only hands on the mounting plate is there a solid connection between it and the frame. My experience the more solid the IMU is attached to the frame the higher you can go with your gains in the wind with out getting oscillations. The benefit of the higher gains again its holding it position better in the wind.

Boris

Hi BorisS, congrats on making moderator!

- I will hard mount the plate on with the IMU is sitting, it's mounted now with rubber buffers. will fix that.
- Going to stick the IMU solid on there with no foam in between.
what would be proper gain settings for this setup then?

Thanks for the quick help guys!

 

[Sebas600]

wow that looks scary with your CX!

 

[BorisS]

Hi Sebas600,

the gyros in the IMU are already isolated from vibrations, thus any additional vibration isolation or play acting upon the IMU could cause it to get delayed or false info of what state your frame is in, or how successful the attempt to regulate the leveling of the copter was. I cant really give you a good answer on what your gains should be it all depends on the frame motors ECS timing props, conditions payload etc. The best is to get the gains:

Normals gains roll pitch yaw, on one slider
Attitude gains roll pitch on a second slider.

I than take the bird up on default setting maybe the normal gains a little higher 150 to 200 and bring the normal gains up until the frame shows oscillation. Once there i bring the normal gains down again to stop the oscillations now knowing what the highest norm gains are the my setup can take. For holding GPS position i than play with the Attitude gains again taking them up as far as possible before the bird acts out with oscillations. But once again in windy conditions your gains might look completely different. For me one flight, before a set of lipos are being drained, were the gains are on the Radio is a must just to optimize the bird for the given conditions. Than of coarse you have to read out the gains in the config tool and set them accordingly if you want to use your x2 and x3 for something else.

Japp that was scary especially because i didnt stop flying it and brought all the gains down to min at some point which was a great experience when a hard gust hit the frame. In a matter of seconds my CX was 40m of position to the left I forgott to switch on the gopro for this one though


Boris

 

[plingboot]

Boris - great explanation thanks :tennis:

 

[lperagallo]

- I've just installed the latest version.
- I will get the GPS unit higher.
- Did not calibrate the "unit"???
- my settings are:

View attachment 3597View attachment 3598View attachment 3599View attachment 3600View attachment 3601View attachment 3602

- The weather was fine, I always check with a helium balloon.
- The MR was in my storage, around 14-15C and took it out to my car 10C and then outside 5C (lipos where at 20C)
- Props are brand new and balanced graupner E 11x5 on AXI 2814/22
- Turnigy plush 40A timing medium
- 2x Zippy 5S 4000MAH paralel

You need to calibrate the compass. Please see page 33. That is important. Also you do need to hard mount the IMU. I use 3Mdouble sided 2mm thick tape with a wire tie around the IMU. I will look at your setttings a bit later today as I am tied up now.

Lou

 

[lperagallo]

- I've just installed the latest version.
- I will get the GPS unit higher.
- Did not calibrate the "unit"???
- my settings are:

View attachment 3597View attachment 3598View attachment 3599View attachment 3600View attachment 3601View attachment 3602

- The weather was fine, I always check with a helium balloon.
- The MR was in my storage, around 14-15C and took it out to my car 10C and then outside 5C (lipos where at 20C)
- Props are brand new and balanced graupner E 11x5 on AXI 2814/22
- Turnigy plush 40A timing medium
- 2x Zippy 5S 4000MAH paralel

That tempature change, if quick, will cause issues. You need to stabilize the temps of the gyros. Is your CG really 4CM below the IMU? Based on your screen shots it appears that you updated to 5.02. If so, did you start by hitting the default button on each screen and then re-enter your parameters? Your gains look a tad low based on looking at the size of your craft and description of batteries. What is teh AUW of the craft.
Lou

 

[Sebas600]

Hi Sebas600,

the gyros in the IMU are already isolated from vibrations, thus any additional vibration isolation or play acting upon the IMU could cause it to get delayed or false info of what state your frame is in, or how successful the attempt to regulate the leveling of the copter was. I cant really give you a good answer on what your gains should be it all depends on the frame motors ECS timing props, conditions payload etc. The best is to get the gains:

Normals gains roll pitch yaw, on one slider
Attitude gains roll pitch on a second slider.

I than take the bird up on default setting maybe the normal gains a little higher 150 to 200 and bring the normal gains up until the frame shows oscillation. Once there i bring the normal gains down again to stop the oscillations now knowing what the highest norm gains are the my setup can take. For holding GPS position i than play with the Attitude gains again taking them up as far as possible before the bird acts out with oscillations. But once again in windy conditions your gains might look completely different. For me one flight, before a set of lipos are being drained, were the gains are on the Radio is a must just to optimize the bird for the given conditions. Than of coarse you have to read out the gains in the config tool and set them accordingly if you want to use your x2 and x3 for something else.

Japp that was scary especially because i didnt stop flying it and brought all the gains down to min at some point which was a great experience when a hard gust hit the frame. In a matter of seconds my CX was 40m of position to the left I forgott to switch on the gopro for this one though


Boris

I'm busy on the full hard mounting the IMU to the frame, next the GPS will go up high on the stick.
How can I set these gains? I use S-bus. X2 and X3 are now gimbal pitch and gain. this came stock.

I'll first fix the hardware and post some pics than I'll attempt to fix the software. I'll try to find someone to film the behavior when flying.

Thanks again for all the help everyone!

 

[Kari]

That tempature change, if quick, will cause issues. You need to stabilize the temps of the gyros. Is your CG really 4CM below the IMU? Based on your screen shots it appears that you updated to 5.02. If so, did you start by hitting the default button on each screen and then re-enter your parameters? Your gains look a tad low based on looking at the size of your craft and description of batteries. What is teh AUW of the craft.
Lou

How have you stabilized gyros for colder temps outside? I haven't done any stabilizing but i've been flying in -9 degrees C without any probs yet. I've just had foamed plastic "case" over imu.

Kari

 

[lperagallo]

Kari,

There is nothing special other than time letting the unit get to ambient temperature rather than changing changes during flight.

Lou

 

[Sebas600]

So here to report back on progress of the re-structuring.

- Fixed the plate on witch the IMU is sitting. removed the rubber buffers and put in aluminum spacers I made for this.
View attachment 2364

- The GPS is now on the medium pole.
View attachment 2365View attachment 2366View attachment 2367View attachment 2368View attachment 2369

- Also refitted the gimbal connection to the frame. I used the rubber 15mm buffers for this at first but with the heavy camera mounted it was rocking to much.
So removed the rubbers and bolted it to the frame with a patch of gyro gel in between.
View attachment 2370

- Moved the receiver to the landing gear and made the 90 degree split in the antenna.
View attachment 2371

Furthermore I don't think that the temperature difference had anything to do with it. the change was very gradual.
I will calibrate the compass and align the IMU and the GPS when the weather allows and change the hardware setup in the assistant.

View attachment 2372View attachment 2365View attachment 2366View attachment 2367View attachment 2368View attachment 2369View attachment 2373View attachment 2374View attachment 2375

Any other suggestions on the hardware?

 

[UAVproducts]

So here to report back on progress of the re-structuring.

- Fixed the plate on witch the IMU is sitting. removed the rubber buffers and put in aluminum spacers I made for this.
View attachment 3622

- The GPS is now on the medium pole.
View attachment 3623View attachment 3624View attachment 3625View attachment 3626View attachment 3627

- Also refitted the gimbal connection to the frame. I used the rubber 15mm buffers for this at first but with the heavy camera mounted it was rocking to much.
So removed the rubbers and bolted it to the frame with a patch of gyro gel in between.
View attachment 3628

- Moved the receiver to the landing gear and made the 90 degree split in the antenna.
View attachment 3629

Furthermore I don't think that the temperature difference had anything to do with it. the change was very gradual.
I will calibrate the compass and align the IMU and the GPS when the weather allows and change the hardware setup in the assistant.

View attachment 3630View attachment 3623View attachment 3624View attachment 3625View attachment 3626View attachment 3627View attachment 3631View attachment 3632View attachment 3633

Any other suggestions on the hardware?

I like your attention to detail. Very impressive.

What are you using for a power Dist. board.?

 

[BorisS]

Its a question of taste how much importance you give that detail. But as far as i know it says in the futaba manual of the small or bigger s-bus receiver version that the antennas should not be touching any carbon parts. In my eyes this is still the best way to have the antennas away from anything disturbing !

View attachment 2377

or this made for the DW frames

http://www.kopterworx.com/Jeti/Jeti-RMK/2-mounting-set

 

[UAVproducts]

I agree about the detail. Its just there is such little room on Multi frames to mount everything that I hate. :dejection:

 

[BorisS]

I agree about the detail. Its just there is such little room on Multi frames to mount everything that I hate. :dejection:

japp that is annoying especially if you want to keep the frame in balance.

Seb to your question before. You will have to give up pitch control until you found your right gains if you want to trim them with X2 and X3. In the auto pilot setting give normals gains those that you want to change X2 and attitude X3 or vice versa, and the camera gimbal if you dont want to deactivate it completely gain 0 i think its called for the manual control speed or deactivate the gimbal completly for you tests.

Thats what i meant before with strapping down you IMU. The frame and IMU are fixed to each other solidly. There is nothing the one does without the other !

 

[Sebas600]

I like your attention to detail. Very impressive.

What are you using for a power Dist. board.?

Thanks!

Don't have a board. Looked for a suitable board but they are all 80-100 amp max. i needed 200 amp.
after numerous testing with copper rings and so on i came to bundling the ESC wires wit the double battery wires and soldered it together!
View attachment 2378

This was the only way to get the ESC's within the limits of the center plate. My 40 amp ESC's barely fit. the ESC's are mounted on an aluminum disk.
Witch I did for the cooling, works very good!

 

[Sebas600]

Its a question of taste how much importance you give that detail. But as far as i know it says in the futaba manual of the small or bigger s-bus receiver version that the antennas should not be touching any carbon parts. In my eyes this is still the best way to have the antennas away from anything disturbing !

View attachment 3636

or this made for the DW frames

http://www.kopterworx.com/Jeti/Jeti-RMK/2-mounting-set

ahhh ok ok will redo it again ;-) that jeti thing looks very good!