Wookong-M first flight

R

RTRyder

Merlin of Multirotors
Just had the first flight of the WKM on my quad test bed frame, WOW! I have two MK Hexa and a Hoverfly Pro as well as a Quadrino and CC board all with auto leveling capability and the WKM is at or near the top of the heap in that category for sure.

The WKM is as good if not better than the MK on autolevel, far better than anything Hoverfly can do both for autoleveling and altitude hold, much better than the Quadrino for both autolevel and altitude hold, and better than the CC as well.

Didn't have time or enough battery left to let it get a full GPS lock but with the LED still blinking it stayed in a fairly tight area with a little wind blowing, if I had the time to let the LED go off I'm confident it would hold just as good as either of my MK, maybe better.

I had the WKM mounted up on my Y6 with Photohigher AV130 but decided to pull it off and put it on the testbed quad until I had a better understanding of how to tune the settings, well that and lack of a mixer table for the Y6! The interesting thing is I didn't change any of the settings and it flys rock solid out of the box with just a compass calibration, this is actually the best this frame has ever flown and its had a lot of different flight controllers on it.

In a while I'll take it out and let it get a full GPS lock then try again, if I can find another pair of hand for the video cam I'll record the flight, I still can't believe how smooth and stable it flys!

Took me less than a half hour to swap it over from the Y6 to the quad, so once I can get the mixer table firmware I'll swap it back to see how it works with a camera gimbal, but so far its looking real good...:D

Ken
 
Last edited by a moderator:


R

RTRyder

Merlin of Multirotors
Bartman said:
Doh! Ken! What did I tell you?!?!

Glad it worked out for you.
Bart
Click to expand...

Just because it works well on a basic quad doesn't mean it can work a camera gimbal though! That will be the real test, if it doesn't work at least as well as the Mk board for roll and tilt compensation then it's just a really nice FPV controller IMO, time will tell but initial impressions are good, so far. At least it hasn't flipped or done anything crazy like some other flight controllers I own...:rolleyes:

Ken
 

C

Crash

Defies Psychics
That sounds great Ken. It looks like a winner.

I had seen a mention that there is a 115 foot height limit for alt hold. Is that true?
 


BorisS

BorisS

Drone Enthusiast
even if the camera tilt and roll compensation dosen´t work as bad as MK and or equal, there is still the hope that DJI might interested in woking on it and making it better. I am happy to hear that its working and that is wasn't just a hype !

Boris
 

Kilby

Kilby

Active Member
Hey guys... I feel like I'm getting to this Wookong-M discussion a little late. Can someone fill me in on the price & features of this package? I just googled it but didn't get much back. Thanks!

BTW.. looks great Ken. I'll be watching this thread.
 

R

RTRyder

Merlin of Multirotors
Flight #2

OK, here's the first negative thing I have to say, the GPS apparently has to reacquire satellites each time its powered on, appears to not build a location file like MK does and its SLOW to lock. Initially the LED flashes 3 times consecutively to indicate <5 satellites acquired as noted in the manual, can't use GPS at this point. 6 Minutes later it went to 2 consecutive flashes indicating <6 satellites acquired (meaning 5???) and OK to fly with GPS. First flight I noticed that it would stay within about a 5 meter circle on two LEDS but its was definitely NOT solidly in place.

Another 5 minutes go by and we're down to 1 flash which is < 7 satellites also good to fly according to the manual, at this point I started the timer on the TX and lifted off. It held better in a tighter circle but still not nearly as solid as an MK. A couple minues later and down to no LED flashes meaning GPS is good to go but at this point it has been close to 15 minutes to acquire a full GPS lock and if that's how long it's going to take each time it flys that is simply unacceptable IMO. Even when I haven't flown an MK in weeks or go to a new location it only takes 3 or 4 minutes max to be fully locked on, 15 minutes before GPS locks on every flight is far too long.

At this point I climbed up to about 100 feet and let go of the controls, it stuck much better now with full lock staying within about a 1 1/2 meter circle with a bit of a breeze blowing or pretty close to what either of my Hexa will do in similar conditions, so the GPS is capable of working well but the satellite acquisition is dismal.

Descent from altitude with attitude lock is markedly better than most other flight controllers I've flown, takes a good gust of wind to make it wobble at all and the vario altitude hold works perfectly, much better than MK's version. Pick an altitude and put the throttle dead center of its travel in ATTI or GPS ATTI mode and it just sits there, no bouncing, first time I've ever seen that happen! Move the throttle a bit in either direction and it will start to climb or descend a corresponding amount, little throttle, slow movement, lot of throttle faster but well controlled movement, they certainly nailed this feature. Transition out of ATTI to full manual can be a bit rough at first the throttle speed tends to change dramatically, if you're not expecting it and at a low enough altitude you can find the multi on the ground before you can do anything about it.

Still using out of the box settings, so now it's time to look at what can be changed and see if there's any way to tighten up the GPS and maybe smooth the transition out of ATTI. Overall not bad at all for a base setup but the GPS satellite acquisition is a killer, hopefully something can be done in the firmware to speed that up because if this is as good as it ever gets I'll keep flying both of my MKs for APV.

Kilby said:
Hey guys... I feel like I'm getting to this Wookong-M discussion a little late. Can someone fill me in on the price & features of this package? I just googled it but didn't get much back. Thanks!

BTW.. looks great Ken. I'll be watching this thread.
Click to expand...

Try this... http://www.djiusa.com/

Ken
 
Last edited by a moderator:

C

Crash

Defies Psychics
I'll bet there's a battery backup for the sat data or some other method. They would not have gone this far to forget to save the sat data somewhere. It's just too obvious of a thing to do for them to overlook.

It takes 15 minutes or so of seeing the same satellite to receive all the data. Sometimes that gets interrupted and it has to start from the beginning. I would leave it outside for a couple hours and see what happens. Also, maybe there's a batt that has to be charged in the sat unit.
 

R

RTRyder

Merlin of Multirotors
Crash said:
I'll bet there's a battery backup for the sat data or some other method. They would not have gone this far to forget to save the sat data somewhere. It's just too obvious of a thing to do for them to overlook.

It takes 15 minutes or so of seeing the same satellite to receive all the data. Sometimes that gets interrupted and it has to start from the beginning. I would leave it outside for a couple hours and see what happens. Also, maybe there's a batt that has to be charged in the sat unit.
Click to expand...

Would be nice if that were the case. Three flights now, same thing each time, minimum of 6 minutes to get enough sats to use GPS if you let it sit still. Last flight I never got any further than that, began flying at two flashes and it never improved during 8 minutes of flight. The difference? Flying in front of the house where there's more trees and a bit less visibility to the sky, appears to be an antenna issue, needs a ground plane or a bigger one than it currently has which can't be any larger than the 50 mm housing the GPS lives in.

GPS aside this thing is incredibly stable and the altitude control is just amazing, its like the multi is hanging from a string. I have NEVER seen a flight controller be able to maintain an altitude like this without any up or down movement at all including when its moving. Don't know how they did it but everyone else could take a lesson from these guys on altitude monitoring and control. The smoothness of FF in ATTI mode almost makes up for the GPS PITA, it certainly would make a heck of an FPV platform and I think I may just give it a try at that this weekend if not sooner.

Ken
 


R

RTRyder

Merlin of Multirotors
BorisS said:
strange they gotta know their **** from the heli units or ?

Check this out http://bbs.5imx.com/bbs/viewthread.php?tid=524777&extra=page=2 :)
Click to expand...

Yeah, I saw that already, thats a big hunk of copper he's got on there but I bet it doesn't take more than 30 seconds to a minute to get a full lock that way. When I swap back to the Y6 which has a flat top I'll give it a try and see if it works, right now the GPS is velcro'd to the top of a dome so not much chance of a ground plane there.

Ken
 

R

RTRyder

Merlin of Multirotors
The word from the DJI folks is DO NOT use a ground plane, it will make things worse. So I asked a question and here's the answer...

Question...
So what will speed up satellite acquisition? The best I've seen so far is a little over 6 minutes which is about 6 times longer than the slowest I get from one of my Mikrokopter GPS.

Answer...
Rx dependent ... Futaba 2.4ghz the best. JR DSM2 as photos above shown. 30 seconds to 5 minutes depends on time of the day.
We do about 100-150 flights per day here, and the same in two other locations in Southern China. Every unit is flight tested.
 

Emowillcox

Emowillcox

Member
I thought that little gps module was supposed to be put atop a holder that dji provided. Thought I saw this on one of the dji video where the little module sits a few inches above the quad.
 

R

RTRyder

Merlin of Multirotors
Emowillcox said:
I thought that little gps module was supposed to be put atop a holder that dji provided. Thought I saw this on one of the dji video where the little module sits a few inches above the quad.
Click to expand...

They do provide a cute little stand with different length shafts to change the height, unfortunately I have no place to mount it on the testbed quad so I have the GPS velcro'd to the top of the dome roughly 7 cm above the IMU.

Ken
 


G

Gary Mortimer

Member
Sounds like noise issues rather than the almanac not staying updated. The very need for the stand points to that. What is the make of GPS used? A good start though.
 

R

RTRyder

Merlin of Multirotors
Gary Mortimer said:
Sounds like noise issues rather than the almanac not staying updated. The very need for the stand points to that. What is the make of GPS used? A good start though.
Click to expand...

I believe that's partially the issue and as far as I can tell it does not build an almanac at all. I just went out back where I've flown it at least three times in the last 18 hours getting a GPS lock all three times and now at 12 minutes I got tired of waiting for the three flashes to go to two so I started flying. Some 4 minutes later it finally went to two flashes, and it was close to 20 minutes in that it went to full lock. To me that pretty much renders the GPS useless if its going to take that long first time up everytime it flys. For comparison I may take the AD6 out and plug it in just to see how it takes to lock, hasn't flown in about two weeks and it was at another location when it did so it needs to fully update the tables, I bet it takes considerably less than 16 to 20 minutes to do it.

As near as I can tell the GPS is their own design as much as possible, have to disassemble the module to see whats inside and that I won't do as long as there's a warranty in play so I have no idea what chips are being used.

I might rig the pole up on the frame somehow and see if increasing the gap between the GPS module and everything else makes any difference.

Ken
 

F

Flying Tivo

Member
I also believe its interference issue, can you try to star the DJI-M with a regular 6V or 7.2v without plugging in the big battery pack. This will effectively let you know if
its the electronics to close to the gps module. Im also in favor of raising the gps module with the provided stand. Let us know.
Thanks
Felipe
 

R

RTRyder

Merlin of Multirotors
I just took my Mikrokopter AD6 out in the yard where I had the WKM a short while ago to test how long it takes the Mikrokopter GPS to cold start and update the internal table. I set my TX to stopwatch function and hit the start button as soon as I plugged in power, the MK GPS went full lock from cold start in 36.4 seconds, so its not sunspots or any kind of local interference that's causing issues with the WKM GPS acquiring satellites. Quite the opposite it appears to be really good conditions for GPS reception right now based on how quick the MK locked on.

Besides all of that, the GPS on the MK sits directly on top of the rest of the electronics stack so it apparently has no problem with being near other electronic devices. That the WKM does suggests a fundamental flaw in the design for use on a multirotor craft and if its that sensitive, why does it take 20 minutes to lock on cold start vs the MK 36 seconds?

Ken
 

You must log in or register to reply here.
Top