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

[kevinw729]

"tzuvela" wrote:
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.)

@tzuvela - if it was that easy then we would avoid it. But sim-sickness is a little more than motion sickness and a little more than motion nausea. It will be interesting to see how OVR will address usage in the disclaimer that comes with the CV1.

"tzuvela" wrote:
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.

Glad to offer it. I will wait and see what the home-brew community can do with simulation, though to be honest I prefer to entrust my butt to professionally built systems.

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

A good "motion" VR experience is still difficult to define till we get some DK2's and start official evaluation on the production prototype. A good motion platform can emulate 6DoF and 4DoF without needing to be too expansive.

We in the DOE sector are making good motion platforms available to a wide user base - most of the most popular systems such as the Cruden platform seen in many theme parks.

" alexroudos" wrote:
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 🙂

Thanks for the observation @alexroudos - it may be a deal breaker to have fast moving cockpit VR without a suitable "physical" representation like a motion base. That would back up the OVR sitting position VR requirement - great news for my sector! Bad news for cheap consumer cockpit VR!! 8-)

[Morpheox]

Nobody have though of adding a computer-controlled fan? it would add a huge improvement in realism, almost as much as aceleration simulation, and much cheaper.

[tzuvela]

"kevinw729" wrote:

Glad to offer it. I will wait and see what the home-brew community can do with simulation, though to be honest I prefer to entrust my butt to professionally built systems.

A good "motion" VR experience is still difficult to define till we get some DK2's and start official evaluation on the production prototype. A good motion platform can emulate 6DoF and 4DoF without needing to be too expansive.

We in the DOE sector are making good motion platforms available to a wide user base - most of the most popular systems such as the Cruden platform seen in many theme parks.

Thanks!
To be hones I'd rather buy professionally built motion simulator platform than build one myself, however I and many others simply don't have tens of thousands of dollars budget.
Can you give us a better estimate to how much would of the shelf 4dof or 6dof platform cost?

Also, in your opinion, would six of these motors;
http://www.motiondynamics.com.au/worm-drive-motor-12v-24v-200w-180-rpm-20nm-torque.html

Would be able to support an average size person in a racing chair (+ the weight of platform for pedals and platform for steering wheel (or joystick):
http://www.ebay.co.uk/itm/BLACK-FIXED-BUCKET-SEAT-FOR-RACING-TRACK-STOCK-BANGER-CAR-/350871245167?pt...

I'd be using Oculus VR so no need for heavy monitors, let's say that motors would have to move 110-120 kg total weight.

Would 1200W be enough or are stronger motors needed?

Thanks, Tino.

[tzuvela]

"Morpheox" wrote:
Nobody have though of adding a computer-controlled fan? it would add a huge improvement in realism, almost as much as aceleration simulation, and much cheaper.

maybe for convertible car or bicycle simulator. Most other fast devices use cockpit or helmet to protect drivers from wind and other boring stuff.

Other industry veterans are also welcome to comment on my previous post.

[Anonymous]

Actually the simple sensation of light air blowing on the face is a very powerful trick to give the sensation of movement, it is used in professional flight simulators.

[tzuvela]

"bongodriver" wrote:
Actually the simple sensation of light air blowing on the face is a very powerful trick to give the sensation of movement, it is used in professional flight simulators.

Hi,
This seems to be already implemented in X-sim
https://www.youtube.com/watch?v=0atLXijAobY