Althold for helicopters

[PistaJ]

To improve Aerial photography results, we are designing Alt hold for helicopters. It will differ a little from the one we already use on our UAVs. See it working in flight here:[ame]http://www.youtube.com/watch?v=uA6w5ow89Go[/ame]

I have already put it on a heli and it worked very well, see it here: [ame]http://www.youtube.com/watch?v=jU17PEaV4YU[/ame]

For the heli use the software needs some changes.
The final price would be about 400 dollars.
Who ever is interested, let me know what the ALT Hold should be capable of.
It is engaged via a separate channel. When in operation the pilot dos not control the collective pitch – at all.
Via the same (enable) channel you will be able to instruct the ALT hold to:
Maintain present level
Maintain entered level - level set by the JetiBox on the ground.

All the servo troughs and settings will be done via the JetiBox. According to my experience – No problem at all with the settings. It is easy.
Collective position when the heli hovers
Max. pitch for climb
Min. pitch for descent.
That is all.

It automatically hovered within 2-3 meters (will tray to improve it. It dependes on the placement of the barometric port) When powered on it reeds the ground zero barometric pressure.

If you enter wanted altitude through the JetiBox, the heli would go there automatically right after the governor is on and the Alt hold is engaged. (You must have some kind of stabilization on board) That one is really impressive. The heli still on the ground, you switch the Alt Hold on and it climbs to the entered altitude and stops there.

No automatic landing at the moment.
I do not think it is important for the reasons it is being developed.

[nightflyr]

Very interesting piece of hardware... though an override feature would be very handy in case of an emergency, also a minimum hard deck height for safety.

nightflyr

[PistaJ]

Hi guys
We have done some changes on the AltHold software.
It hovers much better now. Though we are not done. There will be further improvements to make it user friendly.
The heli is carrying a 3kg payload on a 10m string. The string is there to let you see it really hovers in a height of 10 to 11m. The AltHold on this video was calibrated for the 3kg payload, which is the usual weight my or yours machines must carry. When I dropped the payload in the AltHold mode, the heli climbed up a few meters (above the programmed height) and stopped there. Notice as well what it does when the AltHold is switched on above the programmed level.
The video is found here:
[ame]http://www.youtube.com/watch?v=7pMpMWQ8oBU&feature=player_embedded[/ame]

[PistaJ]

Alhold for helicopters finished.
The unit has been tested and it works nicely.
What it is capable of:
- 7 sec. barometric pressure calibration after power up
- 3 hover points for three different payloads easily set in flight
- Hover at a programmed altitude - set by Yeti box
- Hover at present altitude – this one I like a lot

I have had it on board for several jobs and I am over exited about it.
Anybody interested to beta test it? I think 5 of you would be enough.

My rules:
You will pay 70% of its price
You will get the Yeti box for "free"
Each of you should have at least a different machine, or even other stabilization device than helicommand 3A / 3D / rigid. These are the ones I tested it with.
After you have used it you will let me and the others know how it worked.,
If unhappy let us know why. Return it and we will send the money back.
If happy - keep it for the work you have had with the testing and writing the report for us.
Be aware of not being in control of collective pitch when the althold is active. No matter if it is maintain present altitude or go to the programmed altitude.

[nightflyr]

Originally Posted by PistaJ

Alhold for helicopters finished.
The unit has been tested and it works nicely.
What it is capable of:
- 7 sec. barometric pressure calibration after power up
- 3 hover points for three different payloads easily set in flight
- Hover at a programmed altitude - set by Yeti box
- Hover at present altitude – this one I like a lot

I have had it on board for several jobs and I am over exited about it.
Anybody interested to beta test it? I think 5 of you would be enough.

My rules:
You will pay 70% of its price
You will get the Yeti box for "free"
Each of you should have at least a different machine, or even other stabilization device than helicommand 3A / 3D / rigid. These are the ones I tested it with.
After you have used it you will let me and the others know how it worked.,
If unhappy let us know why. Return it and we will send the money back.
If happy - keep it for the work you have had with the testing and writing the report for us.
Be aware of not being in control of collective pitch when the althold is active. No matter if it is maintain present altitude or go to the programmed altitude.

I think I might be interested in testing it out...but I hope you have a cleaner version than what your have previously posted.. I doubt I could squeeze that on to one of my birds.

As to the 70% of the cost..what is the cost???

[ontheway]

Originally Posted by PistaJ

Alhold for helicopters finished.
The unit has been tested and it works nicely.
What it is capable of:
- 7 sec. barometric pressure calibration after power up
- 3 hover points for three different payloads easily set in flight
- Hover at a programmed altitude - set by Yeti box
- Hover at present altitude – this one I like a lot

I have had it on board for several jobs and I am over exited about it.
Anybody interested to beta test it? I think 5 of you would be enough.

Seems a nice piece of equipment. A quick question, you say it automatically climbs to a preprogrammed altitude, from zero ground. During the climb, I guess the throttle stick will stay in a fixed position, eg., at low (2D setup). When we finish whatever we do at that altitude and turn off the unit to gain control of throttle back, how heli will behave? Should we approximate the position of THR stick to prevent any up or down jumps?

thanks,

[PistaJ]

Hi good question.
You must have a governor on board to do the engine revolutions management.
I use Revlock. Without the governor it wont work.

[nightflyr]

Originally Posted by PistaJ

Hi good question.
You must have a governor on board to do the engine revolutions management.
I use Revlock. Without the governor it wont work.

And how does it function on an electric Heli???

[ontheway]

Originally Posted by nightflyr

And how does it function on an electric Heli???

+1, a natural followup

[imq707s]

Why would you want a system like that on an RC heli? You will still have to keep cyclic control over it wouldn't you? I guess if you wanted to hover all day at the same altitude....but who does that? Maybe for taking video?

Just wondering....

[ontheway]

Along with electric question from night, also wondering how it reacts to barometric changes, guess weather cannot change radically in a few minutes flight, but might be good to know possible side effects, in such case.

[PistaJ]

Barometric pressure changes surprisingly quite fast sometimes.
So would the height of the helicopter in althold mode as it is the barometric pressure the device uses for sensing the height.
All the AP people would know what to use it for. On the other hand those who do not do this bussines have no use for this device.
It should function on electric helis very well.

[rcjpth]

cool - seems to be smart device - should have someone marketing it for you..!

[vanguy]

I don't get the benefit of a alhold for your average RC heli flyer. For people that poo poo flight stablization, this will really set them off

[ontheway]

After questioning about status of heli after switchoff of althold, I saw second video on post #1. At the end, you switch off the unit and heli moves up-down pretty well. I am not sure how much the governor helped there.

Assuming the unit's itself knows throttle percent applied on any moment (when unit in use), thinking of two solutions:

- throttle priority may be adjusted via a knob, while adjusting thr. stick on the TX, so you can gain thr. priority back slowly, in the end, heli pilot will more or less know where the stick should be for the given altitude.

-Another alternative is comparing current percent of thr. stick on the TX (position of the stick actually) and thr. percent applied by the unit at a specific moment, if they are within, say 5-10% range each other, then a couple of bright leds on heli may blink to indicate this stick position is good for switching the unit off.

Well, just some ideas..

[PistaJ]

That is a nice idea, but it is not needed. Before switching the althold off - you move your collective stick right in the middle or just about the point where the heli havers. All of us would know where the point is approximately. This would avoid the jump. Althold and governor work ideally on my set up. I would not let out anything that would be not working perfectly fore me. Lets wait for the beta testers what they have to say.

[nightflyr]

Originally Posted by PistaJ

That is a nice idea, but it is not needed. Before switching the althold off - you move your collective stick right in the middle or just about the point where the heli havers. All of us would know where the point is approximately. This would avoid the jump. Althold and governor work ideally on my set up. I would not let out anything that would be not working perfectly fore me. Lets wait for the beta testers what they have to say.

Speaking of which you still have not given any specifics ... $ amount, final unit packaging size, minimum heli size required, ETC

[PistaJ]

Sorry I am running other threads about it and I am forgetting about what was written where:
http://www.rcgroups.com/forums/showthread.php?t=1150306
http://www.aplanding.com/forums/showthread.php?t=3645
https://www.helifreak.com/showthread.php?t=176598

Althold price 420 USD
size of a small receiver and the same weight. If your heli could carry another receiver and if it fits there - no matter what size the heli is. This device is aimed for the AP using helicopters. A hobby flier will no benefit from using it.

[PistaJ]

Althold special feature - servo signal generator.
I have not enough channels to satisfy my needs. My Althold has a servo signal generator to let me free 1 channel. Would this be useful for you?
Example: revlock governor uses gain channel to set up the revolutions. I can plug it in the althold and set the signal level by JeTi box. The same could be done with gyro 611
Here I might not be correct.
If you do not use the gy 611 gain lead you can not fly AVCS - (is this correct?). Only NOR mode. My gyro 611 gain lead is plugged in to the althold to simulate the sensitivity signal for the gyro.

[Smokytyrz]

Nice work

How does the system behave in winds? Especially winds with widely varying temp (eg. wind chill conditions where the wind is >10F than ambient).