|Aug 30, 2011, 04:42 AM|
Joined Aug 2011
DJI-WKM Multi Rotor Test and Eval
7 years into the field,I'm starting to gain interest on multi rotor. I probed into the related material, and came up with the framework/rack of a multi rotor x6. Looks pretty good in shape (personal opinion)
I have searched multiple brands of rotor (some w/o GPS, some lack self-balance,some difficult to set up, and yet some have special requirements for ESC)
Haveing quite a feiw scattered equipments on hand, I have always been looking for a product with less compatibility reqirements but more stability.I have tried Kyosho 260 with ACE one from DJI, and had good flying result.
Recently, DJI was said to release a multi rotor. Based on the good flying experience and the low compatibility requirement, I nailed the DJI multi rotor prior to its global launch date (Aug 20th, 2011), qualifying me to be the first lot of user to share feedback to the audience
Specail notice: my feedback is only for sharing initial taste to the new product given limited time spent on installation, set up and test fly.
WKM pacakge as usual, crisp and clear, simple and practical.
First thing pops up is a black paper case with installation parts inside.
Underneath the paper case is the four cores parts of WKM: GPS, IMU, Main Controller and Lead Indicator
Accessories inside the black paer case are neatly packed up in Anti-electrostatic packaging.
contents: (receiver)3-Pin Server Cable, double sided tape (3M), GPS sticker, USB cable, GPS bracket and carbon fiber stick
Since GPS interfernce requires it to be 10 cm away from other electornic device, DJI provided an aluminum and carbron fiber GPS supporting frame, which was easy to assemble.
GPS: plastic casing (white with black bg.color)
LED Indicator:aluminum casing designed for heat radiation concern. High kw LED Indicator does gives off heat. DJI's will at least be at 1-2 w.
IMU: with all kinds of important sensors inside. Handle with caution.
Main controller: perform main calculation for rotor control
External comparison of DJI ACE ONE Heli Rotor and WKM:
Main Controller: aluminum casing for ACE v.s. plastic casing for WKM; ACE has a larger body.
IMU: aluminum casing for ACE v.s. plastic casing for WKM; Same body size.
WKM plug varies from ACE plug in that ACE is plugged in on the side of the main controller,while WKM is plugged next to the ESC plug, therefore there is a slight change in shape.
GPS: same external feature and material. WKM isolates the LED Indicator, while ACE intergrates it with GPS; ACE has longer GPS cable than WKM, may be caused by the difference of installation position on heli and multi-motor aircraft.
Next, the installation instruction and steps:
First comes the main character-self desisgned and made multi-motor aircraft X 6. (Shaft distance 55 cm; Motor XXD 2212; Propeller APC 1047, BEC 30A; landing gear XA; Cam Mount self-made 2 axis). I have previously used AQ 50D rotor which is a pretty good value for money option.
Simplification of the aircraft during testing, stripping off Unecessary parts.
The original multi rotor aircraft x6 platform is made compatible to AQ 50. The IMU double-sided tape area for WKM installation is rather small. So, I've added one carbon fiber base board for reinforcement.
Stick IMU onto the equip. cab inside the rack/ framework
Next, GPS platform assemble
first, fix the base onto the equip.cab ceilling
then, assemble GPS holder and carbon fiber stick
Note: DJI's orignial design is to connect holder and carbon fiber stick with glue, and provided 2 pcs of varied length of carbon fiber stick.
But in real practice, GPS cable length is subject to adjustment, making connection via glue unpractical.
Therefore, I suggest DJI to change into aluminum stick with jbckscrew or screw thread, making it easy to adjust.
install GPS onto the equip.cab
Put 3M magic stick onto the LED Indicator
Then, install the main controller box, receiver, and cables as per instruction. Installation is quite simple which took around half an hour.
RE: software set up and rotor connection to computer adjustion which is a little more complicated, I will post another topic later.
Thanks to the DJI's software setting wich is relatively simple, the set up took aournd 2 hours excluding the test fly (minor problem encountered but smoothly soved)
Carefully reading the mannual took around 1 hour. Mannual is not updated very well. I have communicated with DJI customer service on improvement.
Too strong of the sun to make a long trip. I performed a simple test fly in the neighbourhood.
I have only conducted the most basic and simple set up and test fly, capturing the simple test result at starter level. More work is needed for perfect result.
Normal mode flying
GPS mode auto hovering
Close, stable and simple.
WKM in general is a rather simple, applicable, stable and controllable multi rotor. Personally, I am quite satisfied on good effect with simple testing setting;
pricing benchmarked against hi-end imported multi rotor; good compatibility with other equipment;close design with better protection making it reliable and safe.
Simple flying vedio attached with moderate flying skill, not so ideal flying condition in the neighborhood with too many tall trees and highrises interfering the GPS signal, and not so good camera.Please ignore the non-high resolution video.
Due to the restriction of the neighborhod, I will not perform auto back home function. I will post new videos flying in larger open ground.
I welcome any feedbacks and exchange of expriences from frinds who are intersted in multi rotor via email: firstname.lastname@example.org
|Aug 30, 2011, 10:11 AM|
Joined Jun 2007
I would much rather take it with to the GPS unit integrated LED unit.
Is there some need to see the LED while flying?
And in any case, why is the LED unit cabling so unpractical, connecting to the cable near GPS unit that is installed on the top of a pole.
I hope this get fixed on next version...
Otherwise it looks nice, and by reports so far seems to perform well.
Thanks for the detailed pictures.
|Aug 30, 2011, 10:20 AM|
United States, TX, San Antonio
Joined Feb 2007
Thanks for the detailed writeup. What is the weight of all the modules separately and together please? Any chance you could post detailed closeups of the top and bottom of the boards in the modules so we can see the build quality and devices used?
Quadrocopter and Tricopter Mega Link Index
|Aug 31, 2011, 03:26 AM|
Joined Aug 2011
The GPS unit has to be away from any electric device. So there is a holder given to you to make sure you GPS unit is instrall high enough.
By the way, this time the LED is not built in the GPS unit it's separated and instrall in the bottom of the X6
|Sep 04, 2011, 01:45 AM|
Joined Jun 2007
To me it just looks unpractical design that the led unit cable is connected to middle of the GPS cable with so big connector and all.
I read also that there is a GPS locking problem (takes long time) and back up battery for GPS position is missing... Hopefully there is updated version of the HW design before next spring when I might be considering buying one.
Thanks to all you who are testing this new product already now and providing the good info, it sure looks interesting product, but not quite ready enough for what I would expect for the price.
|Sep 04, 2011, 04:06 AM|
Lake Zurich, IL
Joined Jan 2008
Do you mean impractical
1) GPS sat acquisition is mainly due to EMI or electronic noises from ESC and rx.
2) Back up battery for GPS ... this is not a DJI practice and found it unnecessary during the last 6 years in autonomous flight system design and sales, because the GPS is used in conjunction to our proprietary INS.
This is certainly not a product for budget minded
|Sep 04, 2011, 05:00 AM|
Joined Jun 2007
Would you share how the INS helps. Is all functionality available before sufficient GPS lock? or should I always wait for full GPS lock before flight (to be able to use position hold, homing...). I read it may take 8+ minutes wait before GPS lock. 8+ minutes wait before flight is not acceptable for me.
Why is the LED status needed during the flight?
And what is the design reason for connecting the LED unit cable in middle of GPS unit cable. To me it seems by the pictures I have seen that the cabling is not practical in this aspect.
I am not budget minded, but I expect a product with top price also to have top quality in all aspects. I do not agree that "beta testers" should pay almost full price for the product as it seems now, but I am thankful to them as they provide necessary information for my decision to buy or not this product. Now it seems, maybe the next version.
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