My dear fellow RC Enthusiasts,

Usually a gyro can stabilize in one plane of movement, so if you want to stabilize for yaw, roll and pitch then you use three gyros stabilising three planes along with three servos for Rudder, aileron and elevator. You use three gyros with three servos independently for three plane of movement.

If you want do this on something that calls for mixing say elevon then you use two gyros after receiver on channel one and two for two plane of movement i.e. pitch and roll and two servos connected through a 'elevon mixing circuit' after the gyros. Similarly for a 'V' Tail mixing set up introduced on channel two and four for pitch and yaw.

My question is when you use mixing function in the transmitter, is there any way of using stabilisation using gyros for the two plane of movement? Like elevon, 'V' tail and flaperon mixing from the transmitter or for complicated mixing like for Quad rotor or Osprey without having to use the external mixing circuit and by using mixing functions of only the Tx and gyros.  

Is there any special purpose gyro for achieving this? Has anyone come across a solution for this problem or attempted such a set up please help out with in any way possible

Detailed schematics, links from the web, your valuable comments, and bright spark ideas all are welcome please.

Putting  two 3-axis gyros on both the mixed servos (between the receiver channel and the servo) should do the trick   (or even 2-axis gyros, if you are worried about only those two axes).

But it will be an expensive affair.

What could be the source and cost of two axis gyros?

Is there no smart way of doing it with multiple of single axis gyros?

The more I think about it, it looks like I jumped the gun. I forgot that even the 3 axis gyros output to multiple servos, so you will have to do more physical mixing.  The Quadrotor design Sai was testing would be a good starting point.

In that case, we can easily go with the simple (1-axis) gyros.  Got to think through slowly on what it would take.

The moment we add external mixers, it becomes an exercise in stability only, as the mixing might just well be removed from the radio  and be completely done physically.

Quote from: anwar on March 03, 2010, 07:22:28 PM
The more I think about it, it looks like I jumped the gun. I forgot that even the 3 axis gyros output to multiple servos, so you will have to do more physical mixing.  The Quadrotor design Sai was testing would be a good starting point.

And I thought you had come up with something. If you cascade two gyros mounted at 90deg, it should work ?

Quote from: RotorZone on March 03, 2010, 08:07:16 PM
If you cascade two gyros mounted at 90deg, it should work ?

You mean two of two axis gyros for each channel under mixing or one each two axis gyro for the two channel under mixing or two each of single axis gyro mounted at right angle for the two channel under mixing?

If I have understood correctly it is two of single axis gyros for the two channels in tandem mounted at 90 degrees plane of stabilisation.

This might still work for a V tail where plane involved are Yaw and Pitch. What about elevon when it is for roll and Pitch, when for roll Servos are required to operate opposite directions for a roll axis of stabilisation.
 
Some rough block diagram or schematics might help please.

It is very surprising with all the complicated various combinations of programable mixing possible with the Transmitter, is it this difficult to introduce a Gyro in the setup?

Are these two axis and three axis gyros available? If so manufacturers details and source links please?

Quote from: RotorZone on March 03, 2010, 08:07:16 PM
If you cascade two gyros mounted at 90deg, it should work ?

That is an interesting thought.  If you cascade two single-axis gyros (and assuming you set them with proper directions for compensation), each should send in a signal that compensates for drift in that plane, and they are additive.  This is what I had in mind when I posted my earlier response, except that I forgot about how the outputs are fed out in 3 axis gyros (I haven't really come across two axis ones).

Quote from: sundaramvelar on March 03, 2010, 09:17:58 PM
This might still work for a V tail where plane involved are Yaw and Pitch. What about elevon when it is for roll and Pitch, when for roll Servos are required to operate opposite directions for a roll axis of stabilisation.
 
Some rough block diagram or schematics might help please.

It should work for elevon also, as each pair of gyros will individually compensate for each servo.  You will need to setup the "direction" of gyros properly so that they compensate for any type of motion.

No schematic needed, as all you are doing should be connecting one gyro to the receiver channel, connect the output of that gyro to the input of the next gyro mounted in 90degrees to the first one, and finally take the output of the second gyro to the servo that drives one of the control surfaces.

Not sure if you will run into any kind of resonance issues etc, only testing can show that.  That is where a 3 axis gyro may perform better, but that is not an option without additional onboard mixing.

And to make things interesting, what will happen if we use only 2 gyros instead of 4 (1 on each servo instead of 2 on each servo), but keep them at an angle (some kind of 45degrees) so that they can catch the drift in both axis ? 

Yep, someone has done this :  http://www.rcgroups.com/forums/showthread.php?t=1115350

Sundaram bhai - Happy take offs ! You have couple of options now !

Thanks Mr Anwar,

That is really self explanatory and a good thinking and a great idea too.

Special Thanks especially to Mr Anwar for the Links and for the resources, idea of 45 degree and Mr Rajesh, RotorZone for the idea of 45 degree placement of Gyros to sense the movement in two planes in reply to my earlier PM. The Links posted by Mr Anwar was very helpful in understanding the Idea of 45 degrees placement of single axis Gyros.

I have now set up elevon mixing of my Depron F-16 (http://www.rcindia.org/electric-planes/depron-f-16-techone-64-mm-edf-modified-with-fixed-landing-gear/ ) through two single axis gyros. The setup apparently seems to work absolutely fine and sensing movement of both roll as well as pitch axis. Even did not have the problem of servo reversing in roll axis due to appropriate placement of Gyros.

Posting photographs now will be posting video on successful flight later. Gyros in the photographs are outside the fuselage for finer adjustment during test flight due to lack of visibility and space for adjustments, will be moved inside after adjustment of sensitivity and gain.