Y 550, and Gimbal controllers:
if you've been following the thread on AG gimbals, you probably know that i am a proponent of Y and to lesser extent Quad for multicopter for AP. While I realize this put me in the minority, I find that for best flight performance in windy condition, Ys are hard to beat. to gain that benefit, you do lose bit of efficiency, but I think most of us are willing to make that trade.
Gary has been asking about the Y conversion kit for a while. he has shrimp and crab kit that he has to put together, but just never had the time, so he just wanted to convert the F550. when Bobolavega showed up with his conversion of both 450 and 550, I had to build one. I just created a simple motor mount conversion and that is all it took (you also need to take it apart and rewire it, but that is pretty easy on F550)
anyway, here is the pic and first good video from the gimbal that is on it.
I am still working on fine tuning it, but pretty happy with current result. To be honest, Shrimp is still better in stability due to compactness of the system and simonK flashed esc, but I am pretty happy with the result so far. but that also makes this an ideal platform to work out the improvements on.
Now, I get lot of question about gimbal controller. Currently, I test using controller built into naza, and HF gimbal controller. so, lets go over the list of available gimbal control solution.
1) DJI WMK : GPS lock Jitter issue. new firmware is out, with major improvement with 400hz and wider servo signal, but GPS jitter issues not completely fixed. there is suspicion that early ones have the gps jitter issue, but latter ones do not. (fixed in line without announcement) naza will set same update soon, so it will be better option since it does not jitter. Naza firmware update is at least another month behind wmk. dwm firmware current has issue with low gain setting, making it very slow to react. . (very problematic for external pot servo that need lower gain) ok for stock servo.
2) Naze32/Baseflight plus: TC, Jihlein and others are working on AHRS implementation of baseflight for Naze32. First examples are flying now, but we are still bit away from first real release code. once that happens, gimbal controller code should be right there. this has 492hz, 500-2500us pwmm width capability with good gain control. I have also used FF firmware with Naze32 and it does work. but its lack of adjust-ability limits usefulness. tried latest and it is closer. no jiter, but have wondering level. (like slow wave made me sea sick)
3) HFGimbal board: currently 3axis with 2axis coming in another month. 2axis will sell for 250 bucks. very flexible and works well. internal works at 800hz, not sure what the output signal speed is at (I guess I need to scope it) signal is adjustable for PWM width and acc (accel rate of the servo, which helps you to tune the servo) you do need to mount the board away from camera to get away from strange yaw coupling. the video in this post was taken using HFG. currently, only available board that works. I like the fact that it will run on 6v or higher. (so no need for separate power connection) downside is that it has issue with some servos and requires signal conditioner to make it work. (basically a buffering chip) kinda pain, but we found a great little conditioner/isolator board that will be offered via tppacks.com
4) openCC: except for availability, this board does have all the features we need. Seismic uses this and get good results. but not sure if they will ever become available. since the gimbal is armed at all times, it is very simple to use. occasional wondering in the roll reported.
5) KK+mem : Mike Barton has graciously wrote a firmware for gimbal control. it has adjustable PWM rate (upto200hz I believe) and pwm width. probably one of the cheapest solution. seem to work . have not personally tested it.
6) Multiwii in general: stm32 port of multiwii showed strange tendency to have twitch due to lack of good filtering of acc signal. but there are people using paris board as gimbal controller, so i am assuming it is IMU dependent. blade strike has had some success with it. not as good as hFG, but lot cheaper.
Still not available to eagerly waited:
7) PH's Skyline: they are also late in release, and not sure if it will work with none PH gimbals. 250bucks for 2axis. issues with jitters. not fixed yet. requires external pot setup.
8) Cinestar's new board (freefly): designed by famed carvec teamed with tabby, this 3axis board is also not available yet. last rumour to be 500 bucks/axis. Knowing them both, it probably will work well. requires 1 module/axis.
9) KK2. Ole Kaptain Kuk has promised us a gimbal control firmware for the KK2 board as well as AHRS implementation at 20-30bucks, this will be another very affordable and attractive option. but who know when? and what options. Happy sunday has started a openaero firmware and working on gimbal control firmware as well.
10) picloc3. due to availability, this is also kinda hard to find. no real experience with it, but one of the oldest dedicated controller.
11) Eagle tree: eagletree is working on 2 axis gimbal controller based on their autopilot (multicopter firmware is also in the works according to rumourmill) priced at under 100 bucks, it will have good feature set that we are asking for and they are open to suggestions. (which I have also done) need to ask about status now.
did I miss out anything?
for now, still very little choices. but soon to be very plentiful but not there yet
Last edited by askman; Aug 14, 2012 at 01:43 PM.
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