[simpits-tech] Motion cues - a start

[Erwin Neyt]

Guys,

I got hand on a three part paper, written by one of the great pioneers of
flight simulation motion cueing (Reid). I don't have it yet, but I expect it
to be very scientific (mathematical model of the inner ear system).

What they do is calculated what happens in the inner ear in a real plane,
and simulate motion to get an equivalent behavior. 

There are basically four systems to simulate:

1. pitch (and acceleration) 
2. bank
3. yaw
4. heave

The last two are only possible with a very sophisticated setup (6 DOF
systems)

I would be happy to get the first two working. Studies have shown the pilot
performance in simulator went up drastically with simulated motion added.
That means that he was more able to 'feel' what was going on with the plane.

As Marv pointed out, all you should do is give cues (subtle short motions)
to simulate acceleration of movement, not the movement itself. The key point
is how to return the sim to a zero position (straight and level) without the
pilot noticing it (wash out). This is where the difficult part of the math
comes in (high level filters).

As soon as I have studied the papers I let you know if I can come up with a
simpler model (compared to the high end motion sims) which can be used for
home-built stuff.

I still have to start construction of my pit :) and here I am planning WAY
ahead... well, I hope I will someday get there :)

Erwin.

> -----Original Message-----
> From: Marv De Beque [mailto:debequem@speakeasy.net]
> Sent: Saturday, 13 April, 2002 01:04
> To: simpits-tech@simpits.org
> Subject: Re: [simpits-tech] Motion cues - a start
> 
> 
> Alex,
> 
> When I fly, most of the motions that I perceive are much more subtle 
> than that.  First, rolling the sim in the direction of the 
> turn is the 
> wrong thing to do (unless it is simply to provide a little roll 
> acceleration and a few inches of roll is all you should 
> need).  It may 
> sound right, but you really have to think about what is 
> happening to you 
> and your craft in flight and the forces acting on it.
> 
> If you think back to what actually turns an aircraft it is not the 
> rudder, but the wings.  In order to get the wings to turn the 
> craft you 
> must bank the aircraft.  At the point you bank the aircraft, G forces 
> build up and pull you downward into the center of the seat.  The 
> increase of G force is matched by external forces on the 
> wings that keep 
> the aircraft tracking in the turn. It neither slips downward 
> nor upward 
> out of the bank.
> 
> As a pilot you do not feel any lateral forces to either side of your 
> body, just increased G loading.  What you propose would lean the sim 
> over and you would feel a corresponding lateral force into the turn 
> which you ABSOLUTELY will not get in a real plane.  That is, 
> it would be 
> unnatural.  For that matter, you almost never feel a lateral 
> component 
> of G force in an aircraft unless something horrible is happening.
> 
> I like your idea for modeling turbulence.  I think that is where you 
> will get the most bang for the buck.
> 
> If you can develop acceleration cues based on changes in aircraft 
> position (pitch, yaw, roll, etc.) you can add another element 
> of reality 
> to the sim.   However, rolling the aircraft side to side 
> should only be 
> used to give you a little kick and be quickly (not too 
> quickly) returned 
> to level position or you will get a lateral influence from Earth's 
> gravity that will be unwanted.
> 
> Good luck.  I hope to hear more on your experiment as you go!
> 
> Marv
> 
> 
>