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Old Dec 19, 2012, 06:21 PM
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hi guys, i'm having some frustrating problems with my ys.
I had been very happily using the ys on a small hexcopter, until, flying it fpv i flew it into my house. Instead of repairing my hex, i decided to build a better rig. After the crash i checked the FC and everything seemed ok. i was very relived.
I have now upgraded to quad flying on 6 cells and 14" props. it is an ecilop frame similar to zero uav's own steadidrone. Unfortunately i am having problems, and since i have changed every single component, working out the problem is proving very difficult and i am losing my patience.
With my old hexa, i always took off in manual mode 1 very easily, with the new quad take off in mode one is very difficult, it's very jittery and always wants to tip over. But the main problem is that on the last three flights. I am hovering, and suddenly it appears as 1 motor cuts out. on the last this was at about 2 meters and caused considerable damage.
For the last flight i have the hj file. The crash happens at the end(no surprise). If you forward to about the last 1/8th of the playback you will see i take of then settle in to a hover, throttle is at 41. i have taken off in mode 2. i hovered for a minuet with no problems. i then wanted to gain a little altitude then switch to mode 1 then come down to land. however what really happened is i gained a bit too much altitude, then switched to mode 1 then dropped the throttle( right down to 7 in playback) to stop the assent.all fine so far, however once i put the power back on , it flipped and fell to the ground.
My initial thoughts were that i had a problem with 1 motor or esc, as it always appears as if one of the motors cuts out. however there are other factors. Shake and vibration seem quite erratic on this frame. on the old hexa it was always between 3 and 8. on the quad its between 3 and 14 generally. putting on 11" props helped reduce the vibrations and made take off in mode 1 less jittery.
After studying the hj file it seems as though it is not one of the motors cutting out but the fc putting it self in to full left bank with full up and a lot of pan too, even though you can see there is no input from the sticks. You can see just before the crash i dropped the throttle right for a second then put the throttle to about 50%. It is now as put the power back on, now in mode 1 that the vibrations and shake go high, then it forces itself into a flip.
What could make the vibrations suddenly rise, it is not a loose component, this has happened on all my last flights. Is this something i can resolve just by lowing vibrations, Or perhaps i've damaged my imu in the last crash in my hexa.......
Sorry this is such a long post, i hope that it makes sense! Any help would be much appreciated

Thanks, tristan

Ok i can't upload the hj file, says invalid file...any one know how to do that?....
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Old Dec 19, 2012, 06:32 PM
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Is it exhibiting shake? Try adding 5 to motion compensation if it is, and do a test. If it's no better, add another 5 and so on till you dial it out. . Could be you are shaking the imu too much. What the vibration readings say in gcs?
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Old Dec 21, 2012, 02:53 AM
jab
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Originally Posted by whizz101 View Post
I have now upgraded to quad flying on 6 cells and 14" props. <snip> With my old hexa, i always took off in manual mode 1 very easily, with the new quad take off in mode one is very difficult, it's very jittery and always wants to tip over. <snip> however what really happened is i gained a bit too much altitude, then switched to mode 1 then dropped the throttle( right down to 7 in playback) to stop the assent.all fine so far, however once i put the power back on , it flipped and fell to the ground. <snip> Shake and vibration seem quite erratic on this frame. on the old hexa it was always between 3 and 8. on the quad its between 3 and 14 generally. putting on 11" props helped reduce the vibrations and made take off in mode 1 less jittery.
I think you have two problems, vibrations and motor timing issues. Both stemming from using larger propellers.

Vibrations:
Larger propellers generate MUCH more vibration if they are unbalanced. With 14" and larger it is crucial to get them perfect. Sadly there is no sure way of getting there. Read forums and experiment with different propellers, and take your time. A very good/pro setup should not have vibration values above 3-4 during flight, and it can be a lot of work getting there.

Timing issues:
Larger propellers makes it harder for a motor to quickly change speed. Especially if you apply throttle aggressively. Worst case if the ESC timing and motor is to mismatched with the propeller, a quick throttle punch can make the motor lock up and stop completely (sounds like a screaming pig).

Problems getting a stable takeoff can be a combination of both issues. Instead of just applying throttle until you get lift-off, try (in manual mode) slowly applying throttle until you feel the copter is just about to lift. Then take off normally from that point. If this helps you have motor timing issues, if not then most likely vibration problems (assuming you stab settings are correct).
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Old Dec 21, 2012, 03:18 AM
YS-X6 Know why it crashes,blog
New Zealand, Auckland
Joined Nov 2007
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A new tool for analysis
http://www.rcgroups.com/forums/showt...4#post23582864

Export and graph your hj file.

Here is a graph of an earlier fatal crash


http://www.rcgroups.com/forums/showt...9#post22863249

The crash conditions are pretty obvious when you can see it like this.
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Old Dec 22, 2012, 09:26 AM
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Hi everyone this is driving me nuts. I can't seem to do a proper throttle calibration through the gcs

I am using a hitch aurora 9 with Simonk flashed esc. For me to get these esc to calibrate WITHOUT the gcs I have to reverse my TX throttle channel.

But when in the gcs now I have to reverse it back again to get proper function of the throttle.

But now when calibrating through the gcs the esc does not recognize any calibration. Almost like the enpoints are not recognized.

Anyone else using this radio combo with flashed esc?? Thanks!
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Old Dec 22, 2012, 12:33 PM
jab
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Originally Posted by saabguyspg View Post
Anyone else using this radio combo with flashed esc?? Thanks!
Sorry I'm on Futaba. I had no problem calibrating SimonK ESC's with the YS-X6 there.

Separate power on the YS-X6 and the ESC's.
Powered up the YS-X6 first and enabled "Init Setup" mode.
Full throttle, then power to the ESC's. Waited for the motor stick calibration audio sequence and then throttle down.
"Quit Setup" and done.
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Old Dec 22, 2012, 06:36 PM
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I think it stems from the fact my throttle has to be reversed in my tx to calibrate the esc and the Gcs does does not like this .

I am pretty sure that's also why my motors don't spin up at the same time and also it flies like crap
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Old Dec 22, 2012, 06:56 PM
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Quote:
Originally Posted by saabguyspg View Post
I think it stems from the fact my throttle has to be reversed in my tx to calibrate the esc and the Gcs does does not like this .

I am pretty sure that's also why my motors don't spin up at the same time and also it flies like crap
have you tried these instructions?

http://www.rcgroups.com/forums/showp...&postcount=853
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Old Dec 22, 2012, 07:27 PM
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Thanks for the link but with the new Gcs there is no more enable insurance like before... Unless I am missing it
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Old Dec 22, 2012, 07:59 PM
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Originally Posted by saabguyspg View Post
Thanks for the link but with the new Gcs there is no more enable insurance like before... Unless I am missing it
I use the ipad version. "enable insurance" is there.
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Old Dec 22, 2012, 11:37 PM
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Quote:
Originally Posted by saabguyspg View Post
Hi everyone this is driving me nuts. I can't seem to do a proper throttle calibration through the gcs

I am using a hitch aurora 9 with Simonk flashed esc. For me to get these esc to calibrate WITHOUT the gcs I have to reverse my TX throttle channel.

But when in the gcs now I have to reverse it back again to get proper function of the throttle.

But now when calibrating through the gcs the esc does not recognize any calibration. Almost like the enpoints are not recognized.

Anyone else using this radio combo with flashed esc?? Thanks!
I have got Same Radio, ESC with YS-X4 and same problem for ESC calibration.
My Radio Throtlle channel reversed.
ESC's not initialize same time. One motor spinning first and then others.
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Old Dec 23, 2012, 09:40 AM
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Widelec thanks, I have a hex and two ore more motors are not starting. Also I can only get half the motors to shut off when tilting the hex from side to side so the throttle outputs are definitely out of wack.

Maybe we have to add an onboard servo reverse for throttle.

Steve
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Old Dec 23, 2012, 09:54 AM
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Quote:
Originally Posted by fajar View Post
Quote:
Originally Posted by saabguyspg View Post
Widelec thanks, I have a hex and two ore more motors are not starting. Also I can only get half the motors to shut off when tilting the hex from side to side so the throttle outputs are definitely out of wack.

Maybe we have to add an onboard servo reverse for throttle.

Steve
I try reverse and normal servo channel . Not solved.

I apply @fajar linked method. (thanks)
Now 5 motor synchronous one not.
works to increase EPA %10 on throttle channel
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Old Dec 23, 2012, 10:16 AM
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Quote:
Originally Posted by Widelec View Post
I have got Same Radio, ESC with YS-X4 and same problem for ESC calibration.
My Radio Throtlle channel reversed.
ESC's not initialize same time. One motor spinning first and then others.
If I start off and apply a gentle throttle, mine does the same. Generally it is motor 4 that lags. Just put it in GPS mode and take the throttle up to 50% and higher and take off. And when landing motor 4 stops 1st. But the system flies extremely well. Both the YS-X6 and the YS-X4.

Maybe it is because motor 4 seems to be always on the high side as I never take off from a level platform.
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Old Dec 23, 2012, 11:26 AM
jab
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Remember that your throttle stick is not directly connected to the motors. Instead you are telling the autopilot you want to ascend or descend and it decides what motor output is needed to achieve the wanted result. So unless your copter is perfectly level the motors may not start at the same time. Simply because it is trying to level the copter while lifting off.
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