Photohigher skyline rsgs
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I had that pan problem so contacted PH. I was told that they know the stock pan servo is crap & suggested replacing it with a Savox 1258 (modified of course). Huge improvement :nevreness:
Another example of Photohigher's useless customer communication - "We know there's a problem but we'll keep the solution to ourselves!"
tahoelight
Member
I feel like I need to replace all of the servos on my av200 360. I also have the issue where large sweeping moves hold fairly well, but if there is any wind at all and the ship has quick movements, or even when calm and I start a movement, the video shows it as a tilt issue or horizon shift. It is the small quick movements it can't handle at all. My last flight I tried turning up the gains, but it shows distinctive jitter now, so have to slow it back down. I am back to 1.2.2 since I had to reinstall the firmware yesterday and that is what was available on the website. I think that is also why I noticed the jump on the pan when I plugged it in.
iceman
Member
Thanks ATF, I feel like I keep adding upgrades to this thing. First it was a 3 turn pot with 72 tooth gear and 6v BEC, then pan axis compression bearing upgrade, then RSGS and now a new servo. I'm starting to see a pattern emerge. OOPS!!! nearly forgot the camera plate stiffener.
I use a FreeFly servo on the pan for my AV130. Huge improvement in that jerkiness. However, I find the pan stabilization almost useless. With pan stabilization on - when the camera operator tries to pan manually it is very jerky and unreliable. So I haven't been using pan stab.
And since I'm using Radian on roll - the only thing I'm using RSGS for is tilt.
TB
And since I'm using Radian on roll - the only thing I'm using RSGS for is tilt.
TB
What I have found most disappointing through this rsgs experience has been the attitude of photohigher. For a company who have sold many, many gimbals and stabilistaion units across the world there complete disregard for any meaningful customer service is very poor. Why not invest some of our hard earned cash that we have given them into some form of structured customer/product support service. This customer neglect is not just isolated to their rsgs unit. 237 pages of mostly difficulties and now they decide to hire someone to write a proper manual? Vent over.
Iceman, the pan servo that comes with the AV200 has a dead band issue, when doing very little corrections right or left it will jump shaking the cam sideways, how i see it its a design flaw if there was more reduction on the pan axis it would be just fine "which is still in theory" cos you would skip the dead band of the servo and push it to work faster. though the servo has tons of torque.
as for my problem the cam is very well balanced in all axis. i take too much time making this right since for me it is the most important thing in the gimbal. but the tilt & roll problem for me are different from the one you noted about the pan.
by the way for the pan i don't use stabilization on it. its directly connected to my receiver and in the remote control i configured it in a way to skip this dead band where the servo jumps and not rotate smoothly and i limited the speed now panning works 100000% for me. i love it.
though i wish i can say the same for the tilt and roll.
Smooth pan for AV200
Ice man and others......the only mod i have had to do was the pan. I too found it a bit jerky when manualy controled to acheive a smooth slow pan.....particularily with the camera i use zoomed to anything over 150 mm.
Solution.....replace the pan servo with the same as the tilt servo. I did try another servo that i thought might be suitable but it created lots of other issues with the rsgs stability.
I dont fully understand why but using other types and brands of servos dont work as well as the original Savox it came with. I can only asume its to do with frequencies and such that the rsgs was designed for.
With the tilt Savox servo fitted to the pan i can acheive smooth pan rates right down to 1 deg/second at up to 220mm zoom and the pan stabilisation is absolutely perfect with the right gain settings.
I have reverted to the 1.2.2 as for me it gives an overall better result with my set up and the way i use it. 1.7B did work well and better in some ways but had other issues that effect different setups differently and i will wait till those are solved before i go back to it. Please keep in mind my rig is fitted to a R44 helicopter which has masses more shake and wobble than what most if not all of you guys would be getting with your aircraft.
Another point that hasnt received a lot of attention that could be causing greif for some of you as it gave me huge problems at first...."VIBRATION".
Any and i meam ANY... vibration getting thru to the rsgs is going to cause you major stability problems.....not just for RSGS but any camera with a rolling shutter will be effected to some extent. I even had to make a sorbathane isolator mount to go between the camera tray and camera as the high frquency hum of the tilt servo was disturbing my video. I dont know how you guys balance all your rotating bits but get it as good as possible and it may fix some of your issues. Vibration whether 25000 hz or 25 hz is the biggest killer of electronically stabilised video platforms....except for crashing.
While on the servos.....for interest.....i didnt have one of the dummy resistor plugs when i fitted the new servo so i simply set the old trim pot in the middle with a multimeter and it is still there today... works perfectly.....just thought id mention that as there was some speculation that the tolerence of resistors was causing problems....i doubt it very much...but i could be wrong. I cant see the resistance value changing that much in the milliseconds it takes for the rsgs to reference the value
Ice man and others......the only mod i have had to do was the pan. I too found it a bit jerky when manualy controled to acheive a smooth slow pan.....particularily with the camera i use zoomed to anything over 150 mm.
Solution.....replace the pan servo with the same as the tilt servo. I did try another servo that i thought might be suitable but it created lots of other issues with the rsgs stability.
I dont fully understand why but using other types and brands of servos dont work as well as the original Savox it came with. I can only asume its to do with frequencies and such that the rsgs was designed for.
With the tilt Savox servo fitted to the pan i can acheive smooth pan rates right down to 1 deg/second at up to 220mm zoom and the pan stabilisation is absolutely perfect with the right gain settings.
I have reverted to the 1.2.2 as for me it gives an overall better result with my set up and the way i use it. 1.7B did work well and better in some ways but had other issues that effect different setups differently and i will wait till those are solved before i go back to it. Please keep in mind my rig is fitted to a R44 helicopter which has masses more shake and wobble than what most if not all of you guys would be getting with your aircraft.
Another point that hasnt received a lot of attention that could be causing greif for some of you as it gave me huge problems at first...."VIBRATION".
Any and i meam ANY... vibration getting thru to the rsgs is going to cause you major stability problems.....not just for RSGS but any camera with a rolling shutter will be effected to some extent. I even had to make a sorbathane isolator mount to go between the camera tray and camera as the high frquency hum of the tilt servo was disturbing my video. I dont know how you guys balance all your rotating bits but get it as good as possible and it may fix some of your issues. Vibration whether 25000 hz or 25 hz is the biggest killer of electronically stabilised video platforms....except for crashing.
While on the servos.....for interest.....i didnt have one of the dummy resistor plugs when i fitted the new servo so i simply set the old trim pot in the middle with a multimeter and it is still there today... works perfectly.....just thought id mention that as there was some speculation that the tolerence of resistors was causing problems....i doubt it very much...but i could be wrong. I cant see the resistance value changing that much in the milliseconds it takes for the rsgs to reference the value
nicwilke
Active Member
I did several vibration tests, and the RSGS hates vibration. Last night, I did a few 720º spins to watch 1.7b roll stability. You'd seriously not spin as I did if you were trying to get any footage, but found that the horizon stayed nearly flat, and by the 2nd spin, it was caught up. A few weeks back I stuck tape to the props to unbalance them, and read my IMU vibration readings from the YSX6 I'm running, and it was over 10 (maximum safe vibration). I also cable tied the XM's anti vibration hitch tight so it was not isolating vibrations, and found the skyline (then running 1.6) was not doing so great.
I'm happy with 1.7. I had to re tune the servo center in the software to stop them rolling, and then gear up.
Macsgrafs
Active Member
I mentioned several posts ago the resistance changes due to temperature. Several said it wouldn't make any difference...so I went off in search of evidence.
Here is what I have found.
2K5 resistors x 2 (5% tolerance) (temp coefficient +/- 0.05ppm/C up to +/- 2ppm/C)
Lets try & give an example.(purely on a 5% tolerance resistor)
0C temp 2500ohms 5% tolerance would be 2625ohms max & 2375ohms... a total of 250ohms swing. that might not sound much, but that's 10% through just reistor tolerance WITHOUT temp coefficient taken into account! Don't forget its 2 resistors intotal, so multiply the tolerance by 2 giving a total of 20% tolerance...which is totally unacceptable!
EXAMPLE No.2 (1% tolerance resistor)
0C temp 2500ohms 1% tolerance would be 2525ohms max & 2475ohms min...a total swing of 50ohms without taking temp cofficient into the account. Don't forget its 2 resistors in a basic volatge divider layout, so the 50ohms swing must be multilied by 2, giving 100ohms swing.
Many of us have bought cheap resistors of about 5% or if lucky 2% tolerance for a few pennies, when really we should be looking at 1% or tighter tolerances for the value & a temperature coefficient as tight as possible to prevent drift. Check out your resistors, especially the temperature coefficient as this could esily be up to +or- 1700 parts per million per degree centigrade change.
Now I'm not saying this is the problem, but it certainly will not help if your tolerances are to loose.
Ross
Here is what I have found.
2K5 resistors x 2 (5% tolerance) (temp coefficient +/- 0.05ppm/C up to +/- 2ppm/C)
Lets try & give an example.(purely on a 5% tolerance resistor)
0C temp 2500ohms 5% tolerance would be 2625ohms max & 2375ohms... a total of 250ohms swing. that might not sound much, but that's 10% through just reistor tolerance WITHOUT temp coefficient taken into account! Don't forget its 2 resistors intotal, so multiply the tolerance by 2 giving a total of 20% tolerance...which is totally unacceptable!
EXAMPLE No.2 (1% tolerance resistor)
0C temp 2500ohms 1% tolerance would be 2525ohms max & 2475ohms min...a total swing of 50ohms without taking temp cofficient into the account. Don't forget its 2 resistors in a basic volatge divider layout, so the 50ohms swing must be multilied by 2, giving 100ohms swing.
Many of us have bought cheap resistors of about 5% or if lucky 2% tolerance for a few pennies, when really we should be looking at 1% or tighter tolerances for the value & a temperature coefficient as tight as possible to prevent drift. Check out your resistors, especially the temperature coefficient as this could esily be up to +or- 1700 parts per million per degree centigrade change.
Now I'm not saying this is the problem, but it certainly will not help if your tolerances are to loose.
Ross
Macsgrafs
Active Member
If you're not sure of the tolerance then write down the coloured bands or check out the chart below...either way it should start RED, GREEN, RED,?,?
View attachment 9311
A good resistor would have the following colours RED-GREEN-RED-BLACK-PURPLE-YELLOW according to the above chart.
View attachment 9311
A good resistor would have the following colours RED-GREEN-RED-BLACK-PURPLE-YELLOW according to the above chart.
Attachments
Last edited by a moderator:
Macsgrafs
Active Member
No problems, 300v means the maximum...we are talking 5 to 6v normally within a servo.
+/- 0.6ppm/C would mean the following
for every million ohms you would have a resistance value between 1,006,000 & 994,000 ohms
or in our language(using 2500ohms resistors) 0.015ohms deviation (+ or -), very acceptable
Macsgrafs
Active Member
If anyone does try very tight tolerance resistors, please post up a video of your results for us all to see.
As I stated previous, I'm not sure how much difference it will actually make at the values we are talking about because I don't know if the programming of the RSGS has allowed for this...I doubt it as computers deal in truths...either it is on or it is off...there is no gray area!
As I stated previous, I'm not sure how much difference it will actually make at the values we are talking about because I don't know if the programming of the RSGS has allowed for this...I doubt it as computers deal in truths...either it is on or it is off...there is no gray area!
iceman
Member
Hi Ross, thank for info, I've decided to replace the pan servo and will set up the pan in manual mode for now. Can I ask how you set up your TX to skip the dead band?
Macsgrafs
Active Member
hi Iceman, I wasn't the one who gave that reply, but I can tell you how I setup my pan servo.
Firstly it does NOT go through the RSGS, but straight to my RX, to the rudder output. The servo is a savox as per tilt/roll servos on the AV200. I have done the 360 degree mod by snipping out the small variable resistor & using 2 x 2k5 resistors as per PH modification. I then have programmed my DX7 using sub trim to stop the pan servo from rotating, then used a rate switch which includes about 30% expo & a rate of 2% original servo travel..so its very slow in the pan..could do with further reduction really, but I'm sure you get where I'm coming from.
Ross
Macsgrafs
Active Member
Nic...why did you cut the video when you were about to turn? I still see roll drift, even if the video is at half speed. Can you do me a favour mate...go out & do a slow pan/yaw to the left by 180degrees & then back to the right by 360degrees & post the raw footage..without anything done to it...please.
Ross
Ross
iceman
Member
Thanks Ross I can see what you have done and I think I will follow this method for now, my apologies to mounirz who made the original post.