Trim wheel position FSUIPC offset not working?

[OmniAtlas]

If I had to choose hardware to interface a throttle which has nothing in it (yet). I'd use a stepper motor like the one which is build in my throttle. High torque, 0.9° step size (or even smaller when directly attaced to the trim wheel). But instead of a 360° pot, I'd use a high resolution encoder with something like 400 steps/revolution to calculate the current trim wheel position. Starting position could either be detected by a end switch or or a hall-effect sensor.
I would not use a DC motor, because you have to deal with acceleration/deceleration and so on, which in my experience can be quite a pain in the ***. In my opinion stepper motors are a great solution for this.

I haven't really much experience with SIOC / opencockpits. I bought a servo card from them some time ago, but hated the SIOC interace.

The upside with SIOC is that it's widely used in the FS community and you'll probably find a solution to drive the trim wheel with a stepper motor via SIOC. Arduino might be slightly more complex

Cheers, thanks for the tips -- I've heard varied opinions regarding stepper vs dc motors; a few of our fellow cockpit builders here have told me that they had difficulties with stepper motors and FMGS and have gone back to DC motors.

Do you know what would be the best torque/rated speed ? Some of the motors on the phidget website go up to 8.46 kg/cm at a rated speed of 28 RPM.

[OmniAtlas]

HI Ben


This is not what I meant. Only the installer package is always up to date (when possible). I have many, many things to do, work, family etc, and keeping the documentation up to date without forgetting a few things is a nightmare.
That's all

JL

No worries JL, this is after all just a hobby for most of us; no one should be complaining with your free software and continual updates; I think airbus builders have it good.

[Clamb]

Cheers, thanks for the tips -- I've heard varied opinions regarding stepper vs dc motors; a few of our fellow cockpit builders here have told me that they had difficulties with stepper motors and FMGS and have gone back to DC motors.

Do you know what would be the best torque/rated speed ? Some of the motors on the phidget website go up to 8.46 kg/cm at a rated speed of 28 RPM.

I think steppers are better for this job because they can be controlled much more precisely than DC motors. The required speed/torque depends on the transmission between stepper and wheel. My stepper is rated for 11,2kg*cm, 2250 when powered with 12V@2,8A. I'm only powering it with ~1,5A, which is more than enough. You need quite a bit of force to turn it manually when the motor is engaged.

Here is video showing a small speed-test of the setup:
http://dns.reinemuth.de:152/s/lzKBKDAmMsPDTEY

Obviously it's way too fast for normal operation, it was only a test what the motor is capable of. At the beginning you can hear some "grinding". This is the motor stalling due to the mass of the wheel. This does not happen during normal operation.

Here is a video during normal operation:
http://dns.reinemuth.de:152/s/IHxXI8ZDW0yNC5S

It pretty dark, but you can see the wheel turning nice and smooth.

Best regards
Axel

[OmniAtlas]

Cheers for the video. Looks like you have your motor all setup pretty well

I think I may go for a simpler solution using Frisfro software (utilizes dc motor and potentiometer);




It seems the solution may have been sitting in front of me all along.

The Leo Bodnar card supports rotary encoders -- I am assuming this may be compatible with the phidget dc motor + encoders.


PHIDGET MOTOR CARD -> DC MOTOR + ENCODER -> BU836X LEO BODNAR <-> FSUIPC <-> JEEHELL FMGS -> outputs back to phidget motor card.

Am I understanding this correctly?

[Clamb]

Has this setup been confirmed working? I guess you can do it this way
In this setup the logic is controlled by the host PC with the MotorTrimWheelCtr.exe instead of a dedicated microcontroller like my setup, which isn't a bad thing.

PHIDGET MOTOR CARD -> DC MOTOR + ENCODER -> BU836X LEO BODNAR <-> FSUIPC <-> JEEHELL FMGS -> outputs back to phidget motor card.

Yes, but you need to get an initial position at startup. An classic encoder only registers changes in position, relative to the starting position. This means, you either have to set the trim to 0° before startup or add an absolute position detection (end-switch, hall-effect senson, potentiometer).

I've made a schematic of my setup. Looks quite complicated, but...well actually it is

The picture you posted which shows the battery, DC motor and Potentiometer isn't what you are looking for. With this setup you can regulate the motor speed by turning the pot.

Best regards

[OmniAtlas]

Hi Clamb -- I've purchased a 4 dollar motor encoder to experiment with the leo bodnar card and the FDS A320 wheel control software. I will report back my findings

When the plane is on the ground, and the software is started, I believe the trim resets to zero.

In terms of encoder -- yes you are right, it only measures changes in position -- I think it would be possible to set a range of values (limits) with FSUIPC (say from -400 to +1350), when the software starts the trim is at 0, and FSUIPC would be able to read increments or decrements based on the number of pulses you set?

Perhaps the easiest solution is to interface a regular POT, but I am unsure how to do so, or how the motor can feedback to a regular pot.

[OmniAtlas]

Here is a motor I found which may be of interest -- http://www.onlinecontrols.com/mpots.htm

The motors have a potentiometer and a slip clutch.

One of their motors on ebay --




--

Adding a potentiometer to a DC motor -- http://eecs.oregonstate.edu/educatio...1/Section5.pdf

[brianwilliamson]

Gooday Ben, I use a similar motor and OC DC Motor board, for which I have programmed in SIOC.
Make sure you get a motor with a slow enough rpm, and a good variable clutch .

You will need a pot connected to the trim indicator.

Hope this helps..............Brian W.

[OmniAtlas]

Cheers Brian, I think I saw a picture of your setup in one of your previous post.

SIOC scares me but I guess that is one direction to go if you don't mind sharing your script.

Can you recommend a motor?

Regards,

Ben

[brianwilliamson]

Ben....cannot recall the brand of the motor, as it is under the covers at the moment. I can help you out with the script ok .

Let me know how many turns you trim wheel does from full forward to full aft.

You need to get a geared motor probably in the range of 50 to 200 rpm from memory.

Regards................Brian W.