Hi all, I have been flying copters for about 12 months and today i though would be a good day to fly the inspire after testing it in my conservatory and garden. Had a couple of issues were i did not think it was as responsive as it should be as it would drift and fight me to make it return. I bought it back and kept it really low when this happened, it just took off on its own luckily into a bush. I have the most recent firmware and I have also calibrated the imu every time i have turned it on. The compass was also calibrated before flight. Any advice would be great thanks.

when it started to drift my reaction was to let go of the controls so it would stop but it didnt so i quickly tried to rotate but at the point you are right i had lost my bearings . I am honest enough to admit it could of been my error but this with another couple of prob that occurred higher up worries me I think I will find a more open space tomorrow and try again.

I definitely didn't rotate the camera and the inspire was turning on the stick

I suggest contacting DJI and uploading them your flight logs.

Did you do the IMU calibration on a flat surface? This is very important to keep the aircraft stable in the air

I think so but i will certainly do it again tomorrow on the floor. I did it on the case lid but whos to say it was level.

how does this look and how often would you calibrate the imu

After quite a few hours of flying my Inspire without incident, I also had a problem today.  The cute little thing suddenly took off with a mind of her own.  Calibrated IMU just now and going to take it out into a very large field to see how that goes.   I am glad I was low to the ground and had time to steer her lower quickly when I realized I was not the one in control anymore. It happened pretty fast.

Dan

Edit: I had a control issue again on 12 February.  Nothing severe but reminenscent of some GPS holding issues I've read about.  Was not looking at screen during the event so did not know the App's GPS status changed any from the take off status.  I toggled into A mode and regained control.   Went on to fly again with no further issues.

daninperth, are your imu numbers similar to mine, also how often are you meant to calibrate the IMU

The only thing I keep noticing is that compass is very sensitive on Inspire 1. I could fly on Phantom Vision + for weeks without any calibration required.
Inspire 1 on the other hand requires it almost every flight, otherwise you can see it is rather unstable, will go in circles or even will drift in random directions. I have enough experience with big and tiny drones so usually can easily gain control over such things. But compass definitely would cause many of the above issues and very sensitive it seems.

david.spencer.b Posted at 2015-2-1 05:58
daninperth, are your imu numbers similar to mine, also how often are you meant to calibrate the IMU

Hi David,

I took it out for two more runs and it performed very well.  No untoward drift and held position once I took hands off sticks.  I was a  bit cautious at first but because I was in a very large field with plenty of room for error, I swung it around quite briskly.  Tried different modes, let it drift to see what it would do in A mode. Took it full throttle on some longer runs to see if I got the halting effect that you want to see in P mode when not easing off the stick but instead letting it go abruptly. That worked out well it did what it should.   I am tempted to say that the calibration worked.  So to answer your second question, I will now do it before every session.  I don't feel like we should have to but if that's what it takes to replicate that great flying experience then so be it.   You know I did notice a bit of squirrely behavior in the first three flights of the day. I was at higher altitudes and trees were not an issue.  I had more than enough room for what I considered to be slightly abnormal behavior.  However on my fourth flight when my flyaway happened, I was flying very conservatively and in strictly P mode.  I was also flying under tree height when she bolted for the trees.  She took off on her own while I was not even touching the sticks.   I throttled down and by the time she reached the treeline she bounced onto the ground.  When I did react and put my hands back on the sticks, It did not seem to respond to any commands other than weakly to the down throttle.  I really didn't have time to do much else anyway.  

I am going to Calibrate that IMU before each day's session unless someone with greater knowledge tells me otherwise. I had calibrated twice since the last firmware update.  Also make sure you get used to the Inspire's normal behavior...if you get this sorted out that is.  You mention you've been flying already for a year so I guess already know what normal behavior is.  I had many weeks of good stable flight with this machine before today's events.

Edit:  Today I had another event but this seemed different from my first one.   I simply toggled into A mode and then regained control.  This time I was flying at some altitude and wind was steady in the 10 MPH range.

Dan

Hi again David,

My Gyroscope and Accelerometer values are actually very similar to yours but not sure of the value of comparison. I will ask someone here tomorrow.  Since I do not know I talked with my retired NASA friend and he explained to me things I am really not capable of reciting now because my brain is shutting down after that.  I got a very long lecture on his decade of education required to understand things like the challenges of PID algorithms and how hard they are to perfect.    And tomorrow I'm sure he's going to try to insert some of this in my brain while he watches me fly. This is just an excuse to play with the Inspire again but maybe I will learn something. Looking forward to hearing how you go on your next flight after recalibrating.

Dan

Hey Dan,

What exactly happened?? Did you break anything?
And how are you comfortable throwing it up after that!? I'd would be scared out of my mind?!?

Stories like this make me not trust the Inspire at all.

I love the thing, idk what to do though.
I've experienced no problems band was never second guessing it.

But I'm hearing so many stories of "perfect multiple flights" then just out of the blue malfunctions.

This is a roller coaster of a ride.

The IMU calibration is required when the aircraft has abnormal behavior (drifting) with good GPS signal, or app alert you to do that.
The normal value range of Gyroscope: 0.00-0.03 ; of Accelerometer: 0.99-1.01; of Compass: 1000-2000.
When you find your aircraft drifting with a good GPS signal (latest firmware updated), pls send a mail to autumn.a@dji.com, we need your flight log for analysis!
David, stay safe with your second attempt. Keep us posted.

Hi Autum I  will look into it today  and stick it in my drop box or email it to you. Obviously I don't have enough experience with this machine to say 100 percent it wasn't my fault but just before this happened i sent it towards the hedge line and then pulled it back to me. When I was pulling it back it was only traveling very slow even though i had the stick pulled all the way, it was like it was trying to go backwards but i had enough left on the stick to force it my way. If you look in the video as the bird rotates it starts to travel backwards on its own at full pace, coincidence?

Just to add this was flying in beginners mode as i am quite a cautions person, Autum how do i know if I have good signal other than a safe to fly display, I much prefer seeing haw many satellites I have but that has been removed from the app.

Do I need instructions on how to get the flight log

I was lucky and only lost 2 props but it could of been worse, if this happened again in the middle of a lage fiels in beginers mode, am i right in saying it wont travel futher than the 50m mark?

daninperth Posted at 2015-2-1 11:17
Hi again David,

My Gyroscope and Accelerometer values are actually very similar to yours but not su ...

Hey Dan,

What exactly happened?? Did you break anything?
And how are you comfortable throwing it up after that!? I'd would be scared out of my mind?!?

Stories like this make me not trust the Inspire at all.

I love the thing, idk what to do though.
I've experienced no problems band was never second guessing it.

But I'm hearing so many stories of "perfect multiple flights" then just out of the blue malfunctions.

This is a roller coaster of a ride.

Just took it for another flight in a bigger area with less trees and it flew very well in did, almost perfect. This time i calibrated the imu in the take off exact position.


Dave

heres is some data at time of the crash

shakyamunifilms Posted at 2015-2-1 16:46
Hey Dan,

What exactly happened?? Did you break anything?

Hi Shaky,

You know how David said he seemed to be fighting the Inspire before this happened?   Well I noticed this too on three flights.  Nothing severe but If I detect this again I will take it down and recalibrate.  I put it down to a moderate breeze and waited until later for my forth flight because I knew the breeze would abate. Thing is, this thing normally handles wind very well.  I've tested it in moderate wind and it flew well. They even have a place in the manual I think that talks about the maximum wind speeds you should fly in.   If your balance  -- either hardware or software mediated -- is out of whack, wind will really show it off to you.   I believe that is what was going on and if it happens again I will know it fast and recalibrate the IMU since that is the flavor of the month.   My fourth flight, taken after all breeze had abated, showed me this could be a function of the aircraft's imbalance and I should have noticed it before not after my incident.    From what I understand, the capability of that calibration to last is related to software factors that compensate for things and I guess DJI is working on this.   I do not necessarily believe that this problem occurs 'out of the blue'.  Loss of calibration can be gradual. But that does not matter when it comes to someone who is not used to flying it.

No the Inspire was not hurt at all.  I forced it lower. It fought me on this of course.   I recalibrated IMU and went out for two more flights.   Mind you I have very wide open areas to play in so I didn't mind horsing it around post calibration once I saw it was responding to commands as it had done for weeks before.

I know DJI is trying to create a system where the consumer does not have to worry about things like this.     If someone tells David that he is just a bad pilot I'm going to say something.  His description was spot on.   

I am going to be flying this again soon and keep a careful eye on it.  If it is just IMU stability issues then it will become apparent to me earlier than than it did at first.

I guess you can't expect everyone including  me to sense the instability before it starts in earnest.   For that reason guess calibrating before each session and definitely after being stored in travel mode would be a good idea.  I'm no expert in the technical aspects of the control parameters but with the Inspire I do have a feeling of how it should respond to commands and I will know if it happens again.

Dan

Edit: On 12 February had a little issue with no hold at about 30 meters in a steady 10 mph wind.   Toggled into A mode and flew it in without further incident.  Wondering if this was something different.

DJI-Autumn Posted at 2015-2-1 15:55
The IMU calibration is required when the aircraft has abnormal behavior (drifting) with good GPS sig ...

Thank you Autumn for that info much appreciated

Dan

david.spencer.b Posted at 2015-2-1 23:03
Just took it for another flight in a bigger area with less trees and it flew very well in did, almos ...

Thanks for posting that news, David.  Good it seems to have worked.

daninperth Posted at 2015-2-2 06:08
Hi Shaky,

You know how David said he seemed to be fighting the Inspire before this happened?   Wel ...

Hey Dan,

Thank you for that! I feel much more comfortable.
I've been flying today and the past two days, very cautiously. I've seen absolutely no issues, so I'm gradually gaining my confidence back.

I'm performing Compass calibration every flight.
I'm also debating basic IMU calibration before every flight. Also, staying completely away from autonomous flight.

Stay safe up there!!!

Shakyamuni