Autothrottle interface tutorial needed!

[Westozy]

Hi all,
I'm really pleased that my new TQ base has generated quite a lot of interest and a few members have asked me if I can provide the unit with an autothrottle drive. I'm sure it would be an easy task to fit the mechanicals for this but I don't really know how the interface is achieved. If anyone can help it would be greatly appreciated! Can someone please provide a detailed tutorial on interfacing the autothrottle or a link to already published info? Also I need to find out what size stepper motor to used etc and I will build a prototype with the slip clutches and steppers motor fitted. This will then be able to be offered as an option on the basic TQ mechanism.


3635

Cheers and thanks in advance,

Gwyn
Aerosim Solutions

[capetonian]

Hi Gwyn,

I have a load of pics that I have downloaded from the net and from different fora. Because I have downloaded them for reference and do not have the right to post them here, .. I won;t, may I send you a few of these images via email?

Cheers,

Andrew.

[Westozy]

Hi Gwyn,

I have a load of pics that I have downloaded from the net and from different fora. Because I have downloaded them for reference and do not have the right to post them here, .. I won;t, may I send you a few of these images via email?

Cheers,

Andrew.

That would be great Andrew - gwyn737(at)live.com.au

Cheers, Gwyn

[737NUT]

Driving the throttle with servo's or DC motors works well. I used SIOC and OC servo card to drive my autothrottle.

[hca]

Gwyn.

Not quite what you are asking as its not MS but for what its worth.

I guess it depends on the force requirements, But my TQ is the real McCoy and the levers are very heavy even when set to low drag on the adjuster. I could not figure a motor that would move them with out gearing and therefore requiring a clutch, maybe a large stepper? I see others have used RC sail servos but not for this kind of TQ.

I have not seen any one do what I have done but most certainly others would have. Mainly because they are cheap here and easier to get hold of than any other alternative I used 4 wiper motors. ( new about 12AUD each here) I use 2 motors on each thrust lever in a clamp and drive setup.
The shaft from the thrust lever has a section of vee belt on it, one motor has a 50 mm drive wheel on it which drives the shaft running on the belt, at a a nice speed with out to much effort, the other uses the original wiper cam to clamp the first motor over the shaft against a backing bearing just as it goes over the top of its arc. Thus a short pulse of power for simple lock/unlock function for the motor.

This avoided the issue of a clutch or gearing, bearing in mind the force required to move these levers. I don't plan to but I could put a load cell in the linkage or monitor the motor current to detect the pilot trying to operate the lever in auto mode.
But my code will move the lever to desired position, if the pilot pushes hard enough the wheel belt will slip, the processor will see that it had set the position and now its being moved and measure that motion as it occurs. If the moment looks normal, ie not a fault, then autothrottle will release back to pilot command.

As for interface and control, your actual question, I cant assist as my setup is flight gear and microchip pics running on a can bus. No MS here so I have no clue on talking to a non linux sim. I will use one networked pic stand alone to operate the throttles.This set up is still incomplete but I will use the original cut off, idle, firewalled throttle, reverse thruster unlocked, micro switches in the TQ as well as the analog physical position, the on the motors a limit switch on the clamp motors, and interrupter pickups on the drive motors. Each thrust lever being a totally separate device

The pic will also control the original TQ built in interlocks to prevent reverse thrust with out weight on the wheels, and the full thrust lock out.

The other thing is as its flight gear, I mod the code so the relevant autopilot outputs are not fed to the sim code but rather the physical controls. This means one pic can look after all of the sensors and motors on the throttle.

Any how its way to do it with wiper motors. Hopefully helpful food for thought.

http://www.bali-gold.com/Avionics/displayimage.php?album=lastup&cat=0&pos=0 is a zoomable pic of the mechanical set up.

Harry

[Jan737]

Hi Gwyn,

Take a look at this site, it´s in French, but it give a lot of ideas how to make a clutch.: http://www.737ngproject.be/New-TQ.htm

And I'm using a 12 V DC gear motor to drive the levers.
Interfacing is done using the Opencocpits DC motor card and Sioc.

For a code example send me a mail please.


Jan Geurtsen