DC motors weirdo

[barkay]

Dear Fellow builders,

While trying to program my throttle I have come across a very interesting problem. I am using DC motors card from open cockpits with 10K pots connected to DC motors. Even though all my definitions in sioc.ini regarding the device numer and number of cards used seems to be corret I can not get Sioc to see my pot. When I run the DC motors card software eveything starts working but the pot value is not stable and jittering very badly.

First time I connected the card sioc was seeing it and there was no jitter in pot value. Reading was very accurate so the motor was working like a charm within very narrow jitter tolerances.

Does anyone know how to run this without using DCmotors card software in sioc?

Thank you in advance

barkay

[Georg Schneider]

Hi barkay !

The DC motors card from opencockpits is only for connecting your
DC-motor from the trim-wheel.

To connect the pots from your throttle leavers,flaps,speed brake
you need the usb-axes card or any other joystick controller.

To connect the servos from your AT/throttle leavers you need the
usb-servo card from opencockpits.

Kind regards
George

[barkay]

Dear Georg,

Thank you for the answer. Let me make a couple of contributions to your comments. First of all USB axes card can be used as you have said to make things easier in terms of throttle axis. I have managed to use only a single DC motors card by connecting my pots to the same card and get full AT mode working like a charm. It was a minor mistake in my SIOC.ini file.

I am now in the progress of constructing my sioc code so that only one single DCmotors card will be enough for both throttles, speed brake and trim motors.

The reason I am not using servo motors is that they wear quite fast if you play with them so much manually as they have a positioning system inside. Therefore DC motor seemed like a better solution to me as they really do not give up that easily. Of course motor selection is important. I am using only 5 Volts to run the motors and can control the speeds so that I ca simulate the same accuracy as in the real airplane.

So instead of going from a rather easier road by having a USB axes card I have construted everything in sioc therefore only using FSUIPC offsets and not the joystick calibration facilities. This way if anything happens to my system I do not have to rethink of my settings at least as far as the throttle is concerned and it will work with every system running SIOC without no problems.

More coming soon...

Best Regards and thanks again,

barkay

[Georg Schneider]

Hi barkay !

Sounds like a good approach you are in to:D

I`m currently have Leo Bodnars joystick controller for all the pots.

But as you said calibrating is a heck of a job:???:

Looking forward to your method because i`m currently designing and building

a complete MIP-interface including TQ for the Opencockpits mastercard

all with quick connectors and backlighting connectors on the interface pcb.

The same i`m doing for the overhead 3 pcb`s with quick connectors
and backlighting connectors .
The pcb`s can handle up to 13Amp for backlighting.

For the TQ there should be one connector to connect to the
MIP-interface.

Also i`m designing a relay card where you can switch on automatic
all PSU`s for the backlighting when BAT switch is on.

Keep me informed about your results;)

Kind regards and happy building
George

[flyboy01]

Hi Barkay,
I would be interested if you could give me some pointers in getting the dc motors card to work. I have built my TQ as well and am using the same approach as you. However i am using 12volt geared motors for my throttle leavers. I would love to see your sioc file for the programming of your TQ as well as your config ini file for the setup of your dc motors card. I ask this because when i plug my card in it recognises as the usb servos card. and also when i run the controlador program it does not show my pots moving. Is there a seperste test to get the values of the upper and lower limits of the pots travel? If you could either pm me or send me an email to trevor.wimmer@goldenit.net.au this would be greatly appreciated.
Kind regards
Trevor Wimmer

[Hessel Oosten]

Hi Guys,

Please can one of you (or all is the best :-), comment on **the current** for the motors ?

The OpenCockpits DCMotorcard allows 1 Amp per motor
(I presume indeed for 1 Amp per motor and not for the theoretical 6 which can be connected to this card)
and a maximum of 36Volts.

Looking e.g. at datasheets from much (12V) motors the

**Current is frequently above this 1 Amp.**

So, what motor /servo's (brand) do you use ????

Hessel

[flyboy01]

Hi,
The motors i have are from conrad electronics i think. I got the motors supplied as part of my throttle kit. I baught this kit from A guy in the Netherlands I think his screen name is dnoise, and his first name is Jan. i will confirm this in a couple of hours when i go through my email correspondance. I would imagine that because the motor is geared, that apart from slowing the outpout shaft down, that the gearing arrangement provides more torque as well. this would reduce the ammount of current that the motor would need to draw. Someone please correct me if i am wrong. as this is just my understanding of the principles.
Kind regards Trevor Wimmer

[Hessel Oosten]

Hi Trevor and other motor/servo enthousiasts...,

I saw at a friend here in Holland a working TQ that was based on the DCMotor from Conrad nr. 233132.
It works without problems (!), but with a big cooling fan on the OpenC. DCMotor card.

The Conrad site states of the motor: 0,75 Amp, but if you look into the datasheet you can see that I can go up to nearly 9 Amps ! Of course the gearing will reduce that, but it concerns me a little bit. See attached datasheet.

Hope DNoize (Stef) will jump in to clear these difficult (for me) things.

After a discussion on the Yahoo 767 builders forum I found a 24 V motor which is (formally) still a little bit to high but nevertheless has (of course) much lower Amps.
It's a 516:1 reduction epicyclic DCmotor (on 12V an rpm of 19). See both attachments.

Hopefully more technical guy's can give some usefull comments on this.

Hessel

(So see attachments)

[Jan737]

Hi all,

I'm using this one's from Conrad: Bestnr.: 227579 - 89

Max 300 mA.

Best regards

Jan Geurtsen

[Hessel Oosten]

Dank je wel Jan !, Thanks Jan !

This Amperage is fine,

BUT the torque of this Conrad motor (nr. 227579) is 180 Ncm.

The other Conrad motor I mentioned before (nr. 233132) is 5.39 Nm so 539 Ncm, much more powerfull.

So the questions is, is it powerfull enough in your experience ?

Can it overcome the articial friction we "make" to produce a more **realistic feel** ?
Or some more practical, "who" is more powerfull, the motor or your arm ?

Hessel

Datasheet (nr. 227579) attached.

p.s. For some other readers:
1 N is the force required to lift approximately 0.1 kg of mass against earth's gravity.
1 Nm of torque can lift this weight attached to a chain wrapped around a gear whose radius is 1 meter.

[flyboy01]

Sorry my last post was incorrect. Yes the name was Jan Geurtsen that i got my TQ kit from. Screen name is Jan737. Not dnoise. But my experience so far is that the motors that Jan talks about is powerful enough to move the levers provided that you use a friction slip clutch in your set up. this will allow you to move the levers over the motor friction and gearbox friction.

[barkay]

Guys,

Here are the part numbers;

Engines for Levers: partnr. 233132-89
Engines for the Trim Wheel partnr. 233131-89

You MUST cool the chips no matter what as they get really hot, with a heat sink.

@Trev

On my initial trials I started directly from autothrotlle part. I have found the offsets that control throttle movement and made a cross calculation between the throttle max value vs pot max value. As they are moving linear you have to come up with a multiplier to reduce the throttle value to a corresponding value of the pot. As an example if throttle max value is 16245 and pot max value is 255. Divide 255 by 16245 and assign tis to the pot value so the motor will start working. And it will stop once the pot value is reached.

You have to be careful as the pots we buy are not very accurate there fore cuases jittering. Therefore I have given a plus minus tolerans to the pot value for motor to stop in the desired value insead of going back and forward. Below you will find the simple trial code for that;

Var 0001, name Motor_1, Link USB_DCMOTOR, Device 5, Output 1

Var 0010, name A1, Link USB_ANALOGIC, Device 5, Input 1, PosL 1, PosC 127, PosR 255
{
IF &A1 < &potfark
{
&Motor_1 = 128
}
IF &A1 > &potfark
{
&Motor_1 = 120
}
IF &A1 < &potplus
{
IF &A1 > &potminus
{
&Motor_1 = 0
}
}
}

Var 0002, name potfark

Var 0003, name throttle, Link FSUIPC_INOUT, Offset $088C, Length 2
{
IF &throttle <> &threskideger
{
&trfark = &throttle - &threskideger
&threskideger = &throttle
&potfark = &throttle * 0.0049
&potplus = &potfark + 5
&potminus = &potfark - 5
}
}

Var 0004, name threskideger, Value 0

Var 0005, name potplus

Var 0006, name trfark

Var 0007, name potminus


What does the code do? It reads the throttle value once airplaneis in the autotrottle mode and moves the motor to the desired direction till it reaches the calculated pot value. Works very good indeed.

Now I am in the process of reversing this to enable manual lever movement. That means I also have to assign pot value when I manually move the lever to measure the difference between read throttle value and move the airplane throttle paralelly.

By the way I use only 5 volts to feed the card. As the motors are strong enough they can handle mid level power which ca be adjusted from SIOC code to move the levers. So the chips do not get hot so much and it works. For the trim I have not tried it yet.

More details soon.

Regards,

barkay

[Hessel Oosten]

A lot of DC gear motors (12 and 24 V) here:

http://www.servocity.com/html/motors___accessories.html

In the 12 V range really **every rpm output** you can think !!

http://www.servocity.com/html/3-12v_gear_motors.html

Hessel

[barkay]

Gents,

After all these things we have been through maybe a stuid question for some of you but I really have an interesting problem with USB DC motors card. Maybe I can not read Spanish English effectively or maybe I really do not understand basic law of electrics.

2 Throttle arms using 12V DC motors connected to the same card with 12V power supply connected (note: adapter since for some reason ATX power supply burns the card)

Once one of the arms start moving the other stops. One arm comes to its place and starts jittering then the next one moves till it comes to the required point the first one keeps on jittering. Once in the same position everything is back to normal.

Software works fine individually but not with both of them together.

I am assuming that this became and amperage thing.

Now the questions:

1- DC motors manual says 1amp per motor max current. Motor says up to 9 amp. In the case there is a physical force for the motor to move the arm this means motor will use bigger amperes to turn since the inner resistance and the supply voltage is the same correct?

2 - If this is the case and we can not feed the card with more than one amperes do we have to find a physical solution to enlighten the load on the motor to work with smaller current?

3 - In the case that we would like to go with one card then what?

Thank you all in advance

Regards,

barkay

[Hessel Oosten]

Barkay,

The amperage could be reduced by taking a motor on a higher voltage (double the voltage is half the amperage). See previous posts.
If you download the Opencockpits pdf belonging to the USB DC-Motorcard in the code there is an "anti-jitter" part. Probably this is of help ?
I'm really not experienced in this matter, but very interested.., like you are.

Hessel

Var 0000, Value 0 //Initializing Self Positioning DC motor
{
&control = TIMER 999,0,2 // 999 is final value, 0 increase or decrease,

2 is so twice 10 ms
}
Var 0001, name motor // Motor control (0-127) 0=left + 128=right
Var 0006, name ad // Analogic input connecter to potentiometer
Var 0010, name control, Link SUBRUTINE // Subrutine for control (each 20

ms)
{
L0 = &obj - &ad // difference target and measured
L1 = 0
IF L0 < 0
{
L1 = 128
}
L0 = ABS L0
L2 = &velr + L1
IF L0 <= &aprox
{
L2 = &vell + L1
}
IF L0 <= &margen
{
L2 = 0
}
&motor = L2
}

Var 0011, name obj // wished position objective position (fixed in

example)
Var 0012, name margen, Value 5 // % error dead area, ****reduces jitter****
Var 0013, name aprox, Value 20 // points for approach break
Var 0014, name velr, Value 100 // Speed for follow objective, target

motorspeed
Var 0015, neme velr, value 30 // Speed for approach ?? (don't understand

this yet).

[Hessel Oosten]

My message (was here) removed, because it gives confusion i.m.o.

Hessel