Building a 4DOF from the SK3 kit provided by Simukit

Check the Pot gear and the Motor gear. In some Position they Maybe stuck and the Motor is going crazy

Thank you @Ringorumble , I replaced both gears and electrical connection between the pot and the arduino to make sure that they are firm. I am testing again to see if problem still there. Usually it would take a while for that to happen. So far it has not happened yet so I am keeping my fingers crossed.

With a somewhat working motion platform, my next task was to test it with the game Xplane11. I followed the tutorial made by @John458 (https://www.xsimulator.net/community/threads/xplane-11-setup-guide-simtools.11087/#post-156066). The tutorial was made for the UNO Arduino with SMC3 which is different from mine which is using a Micro arduino and sabertooths. However the part on setting up Xplane11 outputs and game patching are similar so I was able to follow most of it. Here are the steps that I did, may be it could help someone new like me in the future:

1. bought the one year download of the game plug in and downloaded the Xplane plugins zip file.
2. started Simtools Plugin Updater and drag/dropped the zip file to it. Then close Plugin Updater
3. started Simtools Game Manager, choose Xplane in game selection, pressed on Patch, enter the Xplane installation directory (e.g., C:\XPlane - 11), make sure patching was successful.
4. started Xplane.
5. started Simtools Game Engine
6. started Simtools Game Manager, choose Xplane in Game Selection, clicked the Game Manager 'OFF' button to change it to 'ON' and see that the status change to "Game Running" from "Not Connected"
7. Tried to fly around in Xplane to see if the motion platform repond to the aircraft dynamic. RESULT: Nothing moved at all...

So I am stuck again not knowing what is wrong???

I also read Simtools quick start guide and used tuning center to capture min/max values but that didn't help. One thing I found happened constantly was that Game Engine would quit unexpectedly. I also used Game Engine output test to check the Virtual Axis output and sometime I saw changes in the values of roll, pitch, heave, etc., sometime there was no change even though the aircraft was moving.

I appreciate very much any help from the community on how to get the motion platform to respond to the game.

I think I have found the problem. It was because the Simtools Game Engine were crashing every time that Xplane was running. And the reason for the crash was that Xplane was sending more data outputs than Game Engine was expecting.

So instead of have just the following in the network data output of Xplane:
3 Speeds
4 Mach, VVI, g-load
16 Angular velocities
17 Pitch, roll, & headings
37 Engine RPM
38 Propeller RPM

Xplane was also containing the following extra setting in addition:
0 Frame rate
1 Times
2 Sim stats
20 Latitude, longitude & altitude

I removed the extra setting and Game Engine no longer crashed. Everything worked after that.

The problem of one motor going crazy once in a while mentioned earlier still happened. I still don't know what happened there.

Hi @stargazer !

I hope everything is fine now (as far as I know you solved your issue with crazy motor). I will follow your thread, don't fortget to mention me if needed

Hi @Wanegain

I followed a tip from @axenic and redo my potentiometer wiring. I also got another tip from Simukit to use a drop of glue to secure the pot gear to the motor shaft. The result is that I no longer have a crazy spinning motor.

What I found was that although the motor no longer spinning, sometime the shaft would spin so that the crank would move from the forward position to the backward position. As a result all my pitch would become reversed of what it should be. It seems that if I limit the motor axis in simtools to just 90 from 100 then the motor would be more stable.

I have not installed the cockpit yet. For now I simply bolted a chair to the platform so that it can be tested.

Here is a video of my daughter riding the roller coaster

You have a LOOOOT of play in the rear right ball joint ! That is not good. You should tighten firmly the balljoint to the "U" shape piece.
Please secure all your bolts, and revise then often, for your own safety.

Wow! you got a sharp eye there @axenic . I did notice that yesterday and had tightened all of them already. It is working much better now.

Good to know. Another piece of advice, you should place a blanket or a gym mat under your simrig : it will save a lot of vibrations.

That is a good tip @axenic . I installed the carpet and the vibration level is noticeably down. Before I was also worry that it could have damaged the floor.

Hi @stargazer, maybe you didn't notice it but I'm Simon from SimuKit

Indeed on the video there was something wrong with a movement as the platform was moving left/right while it absolutely should not.

Hi @Wanegain ,

It is very nice to meet you here. Now that I know you are here may be I don't need to call you on the phone any more .

You may have noticed correctly that my motion platform is not working right. It might be mostly due to my inexperience with Simtools setup and tuning. The part that I found most uncertain is axis setting for the various DOF (roll, pitch, heave, sway, surge, yaw). I don't know what axis should I assign to them and how much percentage is needed. So I entered various numbers by guessing and may be that is why it is not working well.

It would be nice if Simukit provide some guideline for these setting for its platform. Also I have been advised that different game requirement different axis setting. Now I am even more lost of what to do.

Hi Stargazer,
I didn't understand your question about what data to provide into simukit.
So, here is a list of screenshots of my "default" setup :





Axis1a 2a and 3a correspond to each of your motors. You have to test to know which one is which, as it is directly related to your wiring.
Once you have identified your front (or rear) letf and right motors, you will have to determine their direction : this is directly related to the way you placed your red and black wires to the sabertooth.

Let's take for example my heave effect (which I totally randomly set on DOF2). To get all the motors toggle off (the little black box on the left of the effect, labeled "dir"), I had to rewire some of my motors.

I personnaly think it is important to wire your motors that way, as it less twisted-minded to assign your effects.

Let take the surge effect (DOF5) :
I know my axis1a is my rear motor, axis2a is my left motor, and axis3a is my right motor.
What do you want to represent when you encounter an acceleration ingame ? You want to be inclined to the your back, as if you were pushed into your chair.
So, I want to raise equally my left and right motors, and lower my rear motor : I toggled my rear motor.

For the roll effect, the rear motor is not used, so it is not set.

Finally, the % correspond to the % of your axis amplitude used for the effect.
You have to understand that you will likely have other effects applied simultaneously, but very rarely all your effects on the same time at their max.

So the sum of all % must be near 100 (like 100% of the amplitude used), and it can be over it (165 in my case, and I do not feel the saturation.)
If you target something too high (my first settings was at 100% for each), you will saturate your axis, and mask some effects.

Finally, the last picture show the "fine tuning" applied to each axis for each DOF. @yobuddy : this is a pain to have to set values with sliders for all of the axis, would it be possible to have a numeric input box and a "duplicate" button on a next release ?

This is a personal preference, I like to add a little smoothing to all of my axis/DOF, it is more enjoyable.

Thank you @axenic and @yobuddy for the set up tips.

I have been busy working on the traction loss construction. My idea is to use a large lazy Suzan that can withstand a large weight for the traction loss motion. I found one on eBay that is 12 inch large and can support over a thousand pounds. You can see out here https://rover.ebay.com/rover/0/0/0?mpre=https://www.ebay.com/ulk/itm/263794483947 . That costs only $13.10 apiece.

Then I built the wooden platform on top of the motion frame to test out the structure. So far it is working well and is quite stable. It spins readily with me sitting on top of it. I think it will have no problem when I mount a cockpit onto it.

One thing that I did with the lazy Suzan to help it works better was to grease the bearings generously. That helped cut down on the noise and making it rotated smoother.

Now I am waiting for the ball joint parts and screws from Simukit to help connect the motor crank to the platform. After that I should have a pretty good idea how well everything works.

I could not wait for the ball joints and parts to arrive from Simukit. So I just use a thick coat hanger to connect the traction loss motor to the platform. That worked out not too bad. The coat hanger was strong enough to move the platform with me riding on it. This showed that the platform spins well with very little friction.

At the moment the angle of traction loss is probably just between -20 to +20. If the motor was placed underneath the seat, at the center of the lazy Suzan instead, then it could give a much bigger angle range for traction loss. However, even with a small angle of traction loss it is already quite fun to play with.

Won’t putting traction loss on top of the platform result in pitch becoming roll and vice versa at large deflection? I suppose if you keep the deflection small it will not matter. It may result in some strange sensations with large deflections though.

@RiftFlyer thanks for pointing that out. I didn't think of that. May be it is fine the way it is for now. Is this why some simulator, e.g. racingcube, has the whole platform moved on a set of wheels for yaw effect?

Exactly. If you just plan on having very small rapid yaw changes to give the impression of traction loss then it may be ok as it is. As you have it built already you should test it and see. My advice is keep the deflection small so it doesn’t cross over the pitch and roll axis too much.

The cockpit arrived finally this week. It costs just $240.99 from the eBay seller harmoniccd. It is sturdy and pretty decent for the price. It took me the whole day to assemble but so far everything is working well.

The next project will be building a monitor stand to raise the tv up so that it would be at the same eye level as when I am sitting on top of the simulator.

I am also torn between getting two more monitors for the display or just get the occulus rift???

There’s no proper method of doing motion cancellation with the rift yet so I can’t see how it’ll be very comfortable with a 4dof.