Motion Simulator + Oculus + Opentrack or Crystal Cove?

[Anonymous]

Hi Guys,

I've been working on a 2 DOF motion simulator for some time now to use in Formula 3 training. I have built a demo rig (small scale using a 3D printer) and have it running successfully with rFactor 2 and X-Sim, the motion simulator rig interface.

Originally the idea was to use a triple screen setup similar to what most people (even high end simulators) use. Once I saw the Oculus, I was completely hooked, and that idea has now been replaced with the Oculus. It has so many advantages, not only with the stereoscopic view, but the ability to look around makes racing so much more immersive.

In saying that, the only step left is to integrate the motion side of this project with the oculus. But that incurs a massive issue, the fact that the rig moves to simulate forces like acceleration and deceleration causes the viewpoint to move (as the oculus is tilting, pitching and yawing).

There was one discussion on it, but it didnt really lead anywhere as it was more theoretical than anything else.

https://developer.oculusvr.com/forums/viewtopic.php?f=26&t=5027&p=69434&hilit=motion+rig#p69434

Being a robotics engineer, the mechanical and electromechanical parts are straightforward, the only part I struggle with is the programming. This is where I need some assistance in pointing me in the right direction.

The discussion above centered around using the sensors in the rig to counteract the motion in the viewpoint. This however, is not a viable solution whilst using X-Sim. The control system is based outside of X-Sim, where the drivers send game values (such as lateral acceleration, x,y,z positions etc) and X-sim creates motor position values based on filters configured by the user.

It has no feedback as to what is actually occurring on the rig itself. That control loop is processed by the motion controller (be it a Polulu controller, Arduino or custom motor driver).

If the sensor readings from the motion controller were to be sent back to the controller PC, then fed back into game to offset the POV, the delay would be huge, and create massive lag and render it useless.

The best way, is to use an optical tracking system which may already exist. This was TrackIR or OpenTrack.

Using the Rift as the primary tracker, then using the IR/Webcam tracker as the secondary, we should be able to compensate for rig motion, and still be able to use the rift for head position tracking in realtime.

In other words, use the Oculus as the standard headtracker, with the TrackIR led's on the motion rig, and a stationary camera outside of the rig to then add or subtract Pitch, Roll and Yaw to the POV based on the Motion Rigs position.

That would mean that the complete head position should be able to be handled by OpenTrack, then sent out to the game using the standard game protocol injectors.

I know its a long spiel, but I have spent a fair amount of time trying to get this to work and have now gotten stuck here.

Where does Crystal Cove come in? I believe it would be ideal as it has the IR capability built in, but the IR Led's would need to be repositioned onto the rig, not the oculus itself. Then again, you would also loose positional tracking also, but in the instance of F1/2/3 cars, the amount of head movement is extremely limited anyway, and does not detract from the simulator experience.

If anyone can take the time to read and help me out, it would be greatly appreciated.

Cheers,
Eddie

[tzuvela]

This is quite cheap DIY 6dof wiper motor simulator:
http://www.xsimulator.net/community/threads/prototype-6dof.5045/

[kevinw729]

"Eurisko84" wrote:
...I've been working on a 2 DOF motion simulator for some time now to use in Formula 3 training. I have built a demo rig (small scale using a 3D printer) and have it running successfully with rFactor 2 and X-Sim, the motion simulator rig interface.

@Eddie - love your enthusiasm and wish you well with your undertaking.

As you must be aware in the digital out-of-home entertainment (DOE) sector we have a number of 2DoF, 4DoF, and 6DoF motion rigs used for projected and three screen racing simulation. I will not list all of the key runners, but one of the best examples is: http://www.cruden.com/entertainment/our-products2/simulators2/

Regarding the key issues I see from your discussion are these:

- Your Simulator Design
The design you have is similar to SimCraft (http://www.simcraft.com/)


I would wonder it may be better to use their approach, benefiting from the safety OS already developed?

- Using a HMD on a 2DoF rig
I would seriously consider that in offering a limited (two degrees of freedom) rig you will be laying yourself open to sim-sickness wearing a HMD that is not perfect to the motion environment. That may require a boost in performance from your IG and motion platform that could prove prohibitive.

I have a lot of data on HMD sim-sickness and when I evaluated the tech for a project under development using racing rigs we actually considered removing the motion element as the issues of sickness of the the '10%-ers' was too arduous.

If you need more information on the available simulators in this sector let us know, or join the DNA.

[Welby]

With this kind of simulator + Oculus Rift it's just the perfect driving experience.

The wind on your face is the only thing missed :lol:

Awesome!

[kevinw729]

Think some of you should read the statement that:

Sony executive Shuhei Yoshida said that the company had experimented with delayed racer Driveclub but that the results had made him feel motion sickness.

This is with non-motion approach to the racing game experience. We also saw with the iRacing demonstration (search for the discussion on this forum) that only limited head movement worked, and sweeping viewing caused sim-sickness.

Popping a HMD into the race rig experience is not a simple one - no matter how cool it sounds!

[alexroudos]

At 2:05 on the following video

https://www.youtube.com/watch?v=R9Eni2Z7dcI&feature=youtu.be

i am using the rift with LFS. No motion sickness at all and absolutely no problem with the rift from the movement of the simulator.

[tzuvela]

Any thoughts on http://www.xsimulator.net/community/threads/prototype-6dof.5045/ ?

This 6dof should cost less that 1000$ to build. and software is already available.

[kevinw729]

"alexroudos" wrote:

i am using the rift with LFS. No motion sickness at all and absolutely no problem with the rift from the movement of the simulator.

@alexroudos - familiar with the company's products - found the motion a little swashed - you?

Can we also put to bed the statement "...hey I have been using this [thing] and don't get sick!" (paraphrased)
Just because you don't get sick does not mean it wont make others sick, or you may lower your susceptibility and get sick later. For all we know, just kicking up the motion on your system by a few more points and you may spew like a warm can of Bud!

Its not a all or nothing situation. A reason we use the "10%-er" comment is that at present we see a margin of 10% of users to sickness - but as I said this is not a zero sum game, and we need to be focused on thorough evaluation, which sadly DK1 did not give us.

[kevinw729]

"tzuvela" wrote:
This 6dof should cost less that 1000$ to build. and software is already available.

Like building your own HMD - you can spend the time and get some interesting results, but it is still home-brew.
I also am a little skeptical of the level of motion fidelity a home brew can generate - I worked in the commercial and military simulation sector and the safety protocols and general infrastructure needs to be of a high order to avoid simple mistakes. The number of home-brew sim veterans I meet missing the tops of their fingers is concerning.

[tzuvela]

"kevinw729" wrote:

Can we also put to bed the statement "...hey I have been using this [thing] and don't get sick!" (paraphrased)
Just because you don't get sick does not mean it wont make others sick, or you may lower your susceptibility and get sick later. For all we know, just kicking up the motion on your system by a few more points and you may spew like a warm can of Bud!

Its not a all or nothing situation. A reason we use the "10%-er" comment is that at present we see a margin of 10% of users to sickness - but as I said this is not a zero sum game, and we need to be focused on thorough evaluation, which sadly DK1 did not give us.

Can we just say that the simulation is done poorly then?

Some people get sick driving in the back seat of a car, but most people are OK.
Good VR with motion simulator should have the same effects as driving a real car (or plane, space ship, etc.)

Like building your own HMD - you can spend the time and get some interesting results, but it is still home-brew.
I also am a little skeptical of the level of motion fidelity a home brew can generate - I worked in the commercial and military simulation sector and the safety protocols and general infrastructure needs to be of a high order to avoid simple mistakes. The number of home-brew sim veterans I meet missing the tops of their fingers is concerning.

True, but there are communities working on this problem as we speak.
Also I'd be happy to hear your input once I start building my simulator.

I believe is 6dof required for good VR experience and commercial products are not accessible to regular users.

I mentions this build because it is cheapest 6dof simulator I could find.
Wiper motors are 50-100$ each, arduino and motor controllers are also 50-100$ (I believe you need 3 of those)
Bucket racing seat is 100-150$ and frame can be free in you know how to weld.

[alexroudos]

The motion looks swashed but definitely feels as it should. At least this is what i perceive since it feels almost like real driving. As for the no motion sickness, you are right. I shouldn't generalize. The facts are that more than 20 people tried LFS with the rift and with/without the simulator. Without the simulator everyone(including me) wanted to throw up sooner or later. With the sim no one felt like throwing up. The added motion helped our brains in a great way 🙂

A big plus of this sim and any other 2DOF sim that doesn't tilt too much(like the Atomic A2 from Joyride for example) is that they don't affect the rift.