I have had good luck with my Sony CX760V on my CS8/2Axis/Radian setup. But I'm trying to tune the setup for my 5DM3 with 24/IS. I got the new adjustable tilt bars and have the camera very nicely balanced (finally) so it swings freely in both tilt and roll. I'm using standard Radian gains for now (100/100). But what I'm seeing is on certain copter moves, there's a pretty severe bumpiness/oscillation. I have the stock "red" bands on my vibration isolators, and I'm wondering if the gimbal is bottoming out, or something like that. Here's a video that demonstrates what I'm talking about. I've got one motor that's pulling high currents and generating high temps, so I'm going to figure out if it's the motor by swapping it with another one. But for now, I am not sure that has anything to do with this. You'll see some relatively smooth flying, punctuated by the bumpiness I mentioned. I'd appreciate any insight y'all could offer. Thank you!!!
It looks like most of the bumpiness is in the tilt axis, Steve? Would you agree? There's a little bit roll instability in the first ten seconds, but then it seems to be mostly tilt, certainly around 0:16 as you're pulling back. I also note that there are a couple of instances where you might have the copter descending into its own turbulent air which may exceed the ability of the gimbal to stabilize -- I'm not sure of that. Did you alter the gains for the different camera? You've got a different mass-in-motion and I've found I need to adjust for that. Andy.
Yes, in my experience most of this is due to the red rings. Change them out for blue or even black. With the MkIII I get my best stuff with the black. After that you can play with the gains. Id run roll up to 140 and start there. I've also found that you will almost always have a small amount of roll movement but tilt and pan should be smooth 95% of the time. Your descents will always be rough, as Andy said just the result of turbulent air.
The only workaround for the descent that I've found is either (a) ascend and play the footage backwards in post, or (b) do a 45 degree (or thereabouts) descent to avoid the turbulence. Actually this works best if you descend on the upwind side of the ascent so that the wind has blown the ascent turbulence downwind. Andy.
Just discovered this, too. Been wondering about motor 6 pulling a lot of juice, and when testing the motors, found that motor 3 is very noisy. Wonder if that could contribute? Here's a video showing the motor noise. I have the bearing replacement tool, but this sounds like it could be a bent shaft? I guess I'll replace the bearings first and see if it makes a difference.
Yeah. Motor #3 sounds like a two-cycle engine -- there's a "clonking" in there, isn't there. I would replace the bearings. Boca Bearings APEC #7 (don't economize! ) Andy.
I have a couple of the replacement bearings and the installer "tool" that were discussed here a few months back. Are those bearings not as good as the Bocas?
Depends on who you ask. Some folks have been less than pleased with Bocas. Never heard what Josh ended up doing after his replacement story. EZO's seem to be fine. Don't think I will do Boca's the next time. Just good old EZO or equivalents.
Curiously, motor #3 is pulling less power and running cooler than most of the other motors. I wonder if its output is down, so the FC is trying to gun the opposite motors to compensate? This is strange. Motor1: 3.8 7.8 13.0 A Temp: 72 124 154 °F Motor2: 3.4 10.4 16.9 A Temp: 88 144 185 °F Motor3: 0.9 6.3 11.5 A Temp: 86 122 167 °F Motor4: 1.1 10.2 15.3 A Temp: 88 142 187 °F Motor5: 3.0 7.7 12.7 A Temp: 61 140 181 °F Motor6: 0.5 10.8 17.5 A Temp: 63 163 221 °F Motor7: 3.9 7.1 10.5 A Temp: 57 135 181 °F Motor8: 3.7 9.3 18.5 A Temp: 63 144 181 °F
Oops...just saw that I did order the Boca bearings, as well as Bart Cocchiola's tool. So I guess I'll give that a shot, but I do have a spare (new) QC motor that's my fallback plan.
I'll do the swap tomorrow and report back. Very curious as to whether this has anything to do with my problem that started this thread. Maybe not. But I have an inkling...
I swapped out the bearing in motor #3, and it sounded much better. Took the copter to the park (without the gimbal on) and flew around with just a GoPro strapped to the batteries. The resulting numbers look much more uniform, and now I'll re-attach the gimbal and see if I've made any progress towards a smoother video image. Here's the numbers on one of my flights... MK Version: FC HW:2.1 SW:0.88n + NC HW:2.0 SW:0.28o Flight date: 3/27/2013 2:23:55 PM Flight time: 2:23:55 PM - 2:25:45 PM (110 secs, 00:01:50) Batt. time : 337 secs, 00:05:37 Elevation(GPS) : 0 122.2 312.13 ft (min/avg/max) Altitude(Barom.): -4.59 125.83 323.16 ft Vertical speed : -12.63 -0.63 17.72 ft/s Max speed : 20.3 mph Max target dist.: 0 ft Sats : 11 11 12 Voltage : min. 15, max. 15.5 V Current : 8.1 39 69.1 A Wattage : 126 615 1036.5 W Capacity: 3835 mAh Motor1: 2.0 5.3 8.9 A Temp: 100 108 118 °F Motor2: 2.6 6.0 8.2 A Temp: 106 115 129 °F Motor3: 1.0 5.7 9.8 A Temp: 111 126 140 °F Motor4: 0.6 4.9 8.5 A Temp: 108 122 135 °F Motor5: 1.2 4.8 9.6 A Temp: 91 106 117 °F Motor6: 0.6 3.6 9.8 A Temp: 82 102 117 °F Motor7: 2.0 4.1 7.9 A Temp: 88 95 106 °F Motor8: 1.3 4.0 8.0 A Temp: 90 97 108 °F Magnet Field: 100 103 110 % (ok) Magnet Inclination: 53 57 64 deg No errors found
Thanks for posting that data, Steve. Interesting to see the effect a bearing has on performance, isn't it? Andy.
I have narrowed some of my problems down now to the vibration isolators, or so I think. Flying with the CS8 and 5DM3, I am getting very smooth video...some of the time. See here. Black and blue bands are arriving tomorrow.
What kind of temperatures do you have down in San Jose when you were flying Steve? (I think I recognize one of those trees.... ) Andy.
Not to gloat, but it was about 60° or so with calm winds today. And this was up in Burlingame, near SFO. SFO is even visible in the distance in some of these shots. It's at least 3-4 miles away.
Thanks for the info, Steve. I'll be interested to hear what you think of the different colored O-rings.... Andy.