8 replies to this topic

[Vitalik_z]

Hello All.

I need Your help with tuning of CC board.

I've made gimbal and decided to try CC board for stabilization, but met one problem - latency between board movement and signal to servo. I think it is about horizon location delay.
The questions are:
- What parameters influence speed of CC horizon location?
- What parameters influence horizon accuracy?

Here is the test video:



As You may see, when I move construction fast, servos starts compensate this movement after some delay, but when I tried servos directly with Spektrum receiver gimbal movements where more sharp.
Servos are Align DS610.

Thanks beforehand!

Edited by Vitalik_z, 27 January 2012 - 08:39 AM.

[Reddog]

Have you increased the update rate of the servos in the Output screen?

[Vitalik_z]

Yes I have. Now it is 160. Should be higher?

[SeismicCWave]

I strongly believe that any camera stabilization on the market right now is only a damping device. It is NOT going to keep the camera perfectly still. There are just way too many variables involved. You need strong servos with super fast speed to get a good stabilization. When the servo is too fast it will start to over shoot and jitter. I think most people expects too much from camera stabilization. The trick is to fly smooth and steady.

[Vitalik_z]

SeismicCWave, on 27 January 2012 - 09:00 AM, said:

The trick is to fly smooth and steady.

You are right, but there are few video on the Internet that proves it is possible to make gimbals works better

[Reddog]

Vitalik_z, on 27 January 2012 - 09:11 AM, said:

You are right, but there are few video on the Internet that proves it is possible to make gimbals works better

You can get this quality from CC, I have gotten this quality and I did crap all except increase the endpoints and increase servo speed. Increase your servo speeds to max about 330, not that some servos cannot handle the fast update rate. I use super fast (as fast as you can get) heli gyro servos (500 size) with metal gears on my camera mount. The fast, strong servos are a must.

[peabody124]

My strong guess is what you are seeing is essentially due to the latencies in the servos which are probably less when you have a really strong signal going in from large stick movements.  The reason I say this is that the attitude really doesn't have much latency as this is a critical detail for stabilizing a multirotor (it appears to have latency in GCS but that's a separate issue).  If your servos allow you to change settings you might want to see if you can increase their gain for smaller changes.

That being said - the camera stabilization loop runs at 100 Hz which could be adding a bit.  However when I've tried increasing that rate (camerstab.c: 59 change the SAMPLE_PERIOD_MS) CC started acting up.

I think my latencies were less (due to mass and servos) if you look at 3:40

[holco]

May I ask how you set it up?

I am also interested in a CC gimbal only stabilization.

[Adverse Effects]

you would be better off useing a counter balance system and useing springs to control the gimbal from the servos

that way the counter weight is doing the work and the servers are just assisting them

but that is just the way i would look at it

Edited by Adverse Effects, 12 February 2012 - 12:46 PM.