X-Plane 11 6DOF motion platform

Hi @SixDegreesOfFlight
thanks a lot for your videos, it helps a lot.

About the feeling in VR, how does it feel ? does it worth it ? to spend that money ?

Thanks

Great video series again mate, looking forward to seeing the rest coming along.. im about to tackle the motion cancelation system with the oculus... gonna be a fun one i think considering xplane dcs etc are stand alone and not through steam.. looks like there are work arounds for that thou.

Looking forward to a tutorial on the motion cancelation project. if I get the oculus one going ill post a video on that one as well.

Keep up the great work

@dureiken
I hadn't experienced any VR when I ordered my HTC Vive so it was a bit of a long shot. When I put it on for the first time with Prepar3d it was OMG OMG. The thing that strikes you is the scale of things like standing near the tyre of a 747 and looking up - man that thing is massive!

So what happened after I got my Vive? Take a look at the first image. That was my walk-in cockpit for the P3D Carenado C90. Three 42" 1080p tvs, two 19" monitors for the instruments, one 19" for ATC and voice recognition, and one 10" touch screen. It had a full set of Saitek Pro radios / switches etc. It was driven by three pcs.

Now take a look at the second picture. That is what I ended up with a week or two after getting the Vive: it was all I needed / wanted. The VR experience is THAT GOOD.

Sure the clarity could be better / sharper but the feeling of being there just cannot be beaten by a flat screen no matter what size. Once you have experienced VR - you can never go back.

@John458
Thank you! Getting all the images and editing it took more than day - and that was the easy one I think. I have begun work on part 2 but my work commitments are massive at the moment with marking exams and report writing

I mean, what does it feel VR + sim ? compared to VR only

@dureiken
At the moment, to be honest, it hasn't added a lot to VR mainly because I haven't got the platform tuned properly. If you have a look at @SilentChill thread, he spent a lot of time testing and tuning and making modifications. It would be nice to say "Oh I put it together and it worked first shot". Well it kind of did work first shot but like a musical instrument that hasn't been tuned - it makes a sound but it isn't pleasant to listen to. My rate of tuning progress has been slowed by my work commitments but I am enjoying the challenge when I get the time. I do expect the platform to make things much more realistic though, and my goal is to have it playing a symphony by Christmas

I broke it

I was trying to find out why some actuators were not as smooth as others. Using SMC3 utility I used the square wave going around to each actuator in turn...and I found a weak spot Definitely have to use hardwood for the actuator mount points. Chipboard/particleboard is simply not good enough. I will go back in the thread and warn others who may be making the bottom frame from my photos.

I was going to pull the actuators apart anyway to work on the 3D ball screw part rubbing on the frame, so this gives me the reason to start now. I must say that the 'protective table' prevented what would have been severe damage to the electronics and the latching relay circuit / limit switches also did their job beautifully. I have already cut the hardwood replacements and painted them. Not a big job and hopefully at the end of the 'maintenance', it will improve.

I fitted the new hardwood actuator mount so this will not be weak point in the future.

I have found one of the reasons for the vibration and stiffness at low speeds - the anti-wobble ring. I had suspected this but as you can see from the photo it must have been putting a LOT of pressure on the inner wall of the rod to cause the cir clip to bend like that. I think it causes more problems than it tries to solve so I will be removing it from the other actuators as I get around to them. I am confident that once this maintenance is done that the tuning will be easier.

Hi @SixDegreesOfFlight

Can you tell where you bought your gear or whitch brand it is ? mean the Footpedales and leftside stick for pitch in the picture 08.PNG

@kermitkong
Here you go (don't be too shocked at the price - it is best you can buy!)
https://pro-flight-trainer-com.myshopify.com/

Maybe it's too tight? What was the clearance from the tube?

@llluis
It was about 2mm.
X-Plane 11 6DOF motion platform

That might have been not enough clearance but any more then it was not really doing anything. It also assumes that the lead screw is absolutely vertical which it probably isn't. Any small variation from 90 deg at the base is magnified by the length. Given all this, I am not going to keep them.

I have finished two actuators already and the difference in reduced friction is quite large. On my variable power supply, I can get the actuator to move with only 2W of power (1V @ 2A - they are 24V motors). Before the 'maintenance', they wouldn't move until I put about 20W into them. So I am pleased with how this is going.

It's the exact same problem a lot of people (including me) had in the beginning of 3D Printers with woobling threaded rods for the Z-axis. Nothing is used these days, so you are probably right on removing them.

That's quite a big difference indeed. Nice you could measure it.

Hi,

I will begin to build my actuators in a few weeks, 2 questions : how did you thread your U-joint ? and how did you fix ujoint at the top of the carbon rod ?

Edit : 1 more : I have height problem in my room, can I just limit heave in simtools ? but keep high angles ?

Thanks

@dureiken
The top of the carbon rod had a 3D printed sleeve which was epoxied with 3M scotch weld (see page 1 of thread)
X-Plane 11 6DOF motion platform

X-Plane 11 6DOF motion platform

The top bearing is called a Rose joint and the M12 threaded rod was simply screwed into the 3D sleeve with a nut on either end before the epoxy. You can have a look at the photos of the U joint (back near the beginning of the thread) which show how I used more M12 threaded rod and a pin to hold them.

You can set how much you want the platform to move in SimTools from 0 movement up to full extension - that part is straightforward. I would have uploaded my SimTools part 2 if it wasn't for the mishap yesterday

I should be able to finish the other three actuators this week and be back in business by next weekend

Thanks a lot! Good stuff !

@SixDegreesOfFlight , remembered another thing: how's the PETG printed parts coming along with the aluminum profile? No wear so far? Any friction that can be removed if done another way?

@llluis
The PETG doesn't show any sign of wear even when it was rubbing on the V-slot frame. I did try silicon lube which helped but ultimately not enough to reduce the friction very much - it was rubbing over quite a large area. The key is to have the main ball nut 3D part not touch the frame at all - it needs at least a 2-3mm clearance. The 3 lugs only touch the frame to prevent the assembly from twisting so are designed to stop that. They don't have a large surface area so the friction is at a minimum but I will still use the silicon to help.

The platform is now back together after the little mishap last week. The actuator mounts are now hardwood and while I had the actuators apart I shaved off a few mm from the 3D printed rod mount to stop them from rubbing on the frame.

As a result, I have gone from a cheap 6 string guitar in need of tuning to a string quartet! Very happy with how it has turned out or rather tuned in

There were several key issues that brought about the transformation. The first one was lowering the Kp value. The Kp value is one part of the PID algorithm used to improve the responsiveness of the actuator. The initial value suggested is 400. For my motors 24V 450W 4500RPM coupled with a 16mm lead screw with a 5mm pitch, it was way too high. The ball nut simply couldn't keep up and vibrated violently when commanded to go to a new position. I could easily imagine the ball bearings exploding out of the race - it was anything but smooth. The Kp value is set by the SMC utility and I have, for the moment, set it to 150. The PWM is at 200. That can go higher now, I suspect.

The second issue was the tuning center values. This morning I reset the values, and launched the Bell 407 helicopter without the Vive. After turning on Capture I flew (acrobatically) the heli in every conceivable attitude. The pitch, roll and yaw ended up close to each other around +-2.8. Once I saved them, I put the Vive on and took it for a spin. As you can imagine, if you know how the tuning center works, it was way too gentle. Back to Capture. This time, I flew very gently with the Vive on. The values were around +-0.3. Whoa there Nedy - the heli was a like bucking bronco Un-flyable. So the value had to be somewhere between 0.3-3.0. So I started with +-1 but with the Game Manager on 0% for Main slider. When this was increased it was clear that 1.0 was still too sensitive. I ended up with +-2.0 and the Game Manager main slider at 100%.

Lastly, and against my own advice, I increased the Axis allocation to 90% for pitch, roll and heave. There still isn't enough roll movement though. That's why it is a string quartet not a full orchestra yet