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Dimitris76

Pan Cam

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Mr RC-Cam,

how do you think that the camera gimbal would act if it had a heading hold gyro connected between the Rx and the Pan Cam?

I am trying to "simulate" the Gyro's reactions in my mind - controlling proportionally the servo's speed instead of it's position... If the TX stick is in the middle, on the Rx side we'll have 1.5msecs and the HH Gyro will initialize with this value as center point. When the camera platform deflects the gyro which is mounted on it will try to compensate by rotating the servo with speed proportional to the deflection's amount, and when it (the mount) reaches the previous position, it will output 1.5ms again and the servo will stop.... am I right or am I missing something????

Dimitris

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Sound right to me.

The gyro needs to be on the plane and not on the platform though.

Terry

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Sound right to me.

The gyro needs to be on the plane and not on the platform though.

Terry

Terry,

I am talking about a gyro stabilized camera platform here - one that "tracks the target" while I am shooting video from a heli.

What about adding a servo stretcher after the Pan Cam?

Something like this:

R/C Rx --> HH Gyro --> PanCam --> Servo stretcher --> Camera Mount Servo

in order to get 180 degree pan/tilt range...?

Dimitris

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I am talking about a gyro stabilized camera platform here - one that "tracks the target" while I am shooting video from a heli.

I know, it still needs to go on the heli and not the platform, you try it and see.

Remember an HH gyro will not make it track the target just hold the angle of the camera.

What about adding a servo stretcher after the Pan Cam?

Something like this:

I have not tryed that but it should work up to a point. You may find it all gets a bit twitchy.

Terry

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A heading hold gyro essentially has a PanCam in it (but optimized in a different way). With the two together, I don't think the results will be pretty since the Pancam will change the gyro's control loop. But, it's easy for you to try it out -- just plug the stuff together and simulate some test conditions.

An interesting thing with PanCam is that if you install it on a normal rate gyro, the gyro will behave a lot like a heading hold model. Mind you, not a good one, but the characteristics will be very similar.

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Remember an HH gyro will not make it track the target just hold the angle of the camera.

True! It will not track the target while the heli is flying forward or drifting, but it will adjust the camera's angle if the heli rotates (around x, y or z axis with 1,2 or 3 gyros) while hovering, right?

Also I have seen many setups on runryder etc and almost all of them have the gyros ON the camera gimbals....

Your suggestion makes more sense though - having the gyros on the main airframe that has bigger mass.

Dimitris

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Have a look at that (discontinued) product:

http://www.spartan-rc.com/products/visionlock/visionlock.php

it's essentially a PanCam but the designer claims that it has a second mode that supports HH gyros!

If the Pancam board disrupts the gyro's internal feedback loop and every gyro has it's own characteristics, how did they manage to make it compatible will ALL the gyros out there?

Dimitris

PS Check out the videos on the right - especially the one with the pen is really impressive!

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On page 3 of their manual

http://www.spartan-rc.com/products/visionl...VisionLock3.pdf

they suggest setting up the GAIN (on the Visionlock NOT the gyro) to maximum and then turn it down gradually until the oscillations stop. This gain pot is turned all they way down when Visionlock is used without gyro... what is does this GAIN thing do? Is it a parameter that can be configured with a value change on Pancam's firmware?

Also on the 2nd note it states that the Visiolock board has to be installed BETWEEN the gyro and the servo. The Gyro(s) go on the camera mount... Go figure

Dimitris

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If the Pancam board disrupts the gyro's internal feedback loop and every gyro has it's own characteristics, how did they manage to make it compatible will ALL the gyros out there?

By making it tunable, such as is achieved with a gain setting. That alone is not the holy grail, but is sufficient to solve most situations. The mechanical design impacts it too, so a stable system is a compromise of many things.

what is does this GAIN thing do?

It affects the "P" of the PI or PID control loop.

Is it a parameter that can be configured with a value change on Pancam's firmware?

Not on the existing PanCam design. A couple years ago I prototyped a version that was going to support a gain feature and much higher performance. But the market potential seemed too small to justify the trouble to turn it into a final product. So, it is unfinished and mothballed for now.

It would not be much trouble for someone to try the idea out on the bench. If adding PanCam to the HH gyro helps then be sure to report what you find. The two published hex files have different gains, so try them both.

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Mr RC-Cam,

most of your projects use the PIC12C5xx family of controllers which according to Microchip have been discontinued in favour of the PIC12Fxxx series. Apart from the fact that the newer ones can be programmed on the circuit their specs look identical. If I make provisions on the PCB for the programming header is there anything else that I have to consider? Does the firmware work like it should be on the new chips?

Dimitris

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I have not found any problems with using the PIC12F50x parts in place of the PIC12C50x. They seem fine to me.

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hi RC-cam fans,

Maybe a bit off-topic, but I am looking for some-one to program a PIC chip for me for PanCam use. I have no experience in this, hope anyone can help?

Thanks a lot!

Multimul

Edited by multimul

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If you don't want to program one (a very useful thing to be able to do yourself) then I can supply the programmed part at a nominal cost. PM me if you need to do that.

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