First of all, I'd like to take a comparison between two well known simulators on the market:

Force Dynamics:
http://www.youtube.com/watch?v=ld6xT5yfbhw

and

Mechanic Bull:
http://www.youtube.com/watch?v ... 7Cc_Q&feature=related

And I'd like to say that I see no much difference between them!

That said, my intention here is to get some support from the community, and discuss some ideas about the ideal low cost motion cockpit simulator.

I have thinking that just 2DOF and 1 bump would be enough for deep immersion.

About the 2DOF, I'd like to divide the situation in two things: longitudinal movement simulating break and acceleration, and lateral movement, simulating curves. Simple as that.

Later I'll back here to take this discussion back, cause now I'm at my work and have not much time to describe my initial ideas.

I'd like just to say that, IMO, Force Dynamics has a wrong aprouch to the simulation. It looks much more like a mechanic bull, but much more expensive. This is not what I feel when driving. I'm not launched to the air, so I intend to get a different way to simulate the both inertial forces (longitudinal and lateral).

See you later, and thanks.

That's... uh cool. What is cooler is imagining how the seat will be like when you hit a barrier!

The Force Dynamics approach I think is a pretty good one - if you're in a totally dark room where the screen is the only light, you will feel the immersion. Seeing what the machine does ruins the immersion.

What you feel when you move? Inertial force on your body.
The direction of this force (and you feel just one, as a resultant vector of the various), is never sending you to the sky, except when you guide your car to the abyss...

What I see when I watch this FD movies is something like a angry mechanical bull, shooting the driver to the high.

I don't see it as natural movement.

I think the natural would be just horizontal weight, leaving the vertical force to the bump only.

But there is another thing that I'd like you to consider: cost $$$

I can't afford with so expensive machine, and I focalize a market where there is no space for U$20k toys.

So, I'd like to discuss a new concept, while I manage a development of a rustic model for test software and eletronics.

My idea is about what is really necessary to give better immersion to the game.

It has not necessary to be perfect, or to be complete. It just need to be immersive.

We have some gadgets that increases a lot the immersion: Force Feedback Wheel, Buttkicker, TrackIR and 3Head.

These things together are not too expensive today, and increases the immersion to a deep point.

The first two things above are mechanical things.

The big actor is the FFB Wheel. With just this accessory we have many of the contact with the game we wait for.

After a short period of getting used to the system, we find ourselves forgetting the reality and going deep in the game.

My idea is to complement this diving, implementing a motion cockpit that:

- gives good immersion
- be cheap
- doesn't tire the driver (I think FD tires a lot)
- make little noise
- people get interest in buying

See you later

Quote from Speed Soro :

What you feel when you move? Inertial force on your body.
The direction of this force (and you feel just one, as a resultant vector of the various), is never sending you to the sky, except when you guide your car to the abyss...

What I see when I watch this FD movies is something like a angry mechanical bull, shooting the driver to the high.

I don't see it as natural movement.

It does not have to move in a "natural" way. It has to reproduce acceleration you feel in the vehicle. Rolling and tilting in a carefully chosen way around a high pivot point is a very good way to achieve this when you have little or no translation degrees of freedom.

Do not think they are idiots. Read about washout algorithms and motion platforms. This is a very complex matter.

Quote from MAGGOT :

The Force Dynamics approach I think is a pretty good one - if you're in a totally dark room where the screen is the only light, you will feel the immersion. Seeing what the machine does ruins the immersion.

the only thing i don't like about the force dynamics, is that it can't really convey the difference between braking hard, or braking on a steep downhill slope.

Idiots? Where did I said something like that? Be careful, dont put words in my mouth.

I'm not looking for complex math. I was saying about what I can see on the video.

You feel the things with your body, with the pressure over caused by the inertial force.

You feel your head going ahead, you feel your chest being compressed by the safe belts, you feel your arms being tensioned when using the steering wheel as a support, and so on.

But the mainly organ in your body that feels the inertia is the labyrinth, and it knows when your are moving up and down or back and forth.

(http://www.lookfordiagnosis.co ... g=1&term=Ear%2C+Inner)

Frex has a different approach, and it deliveres imersion, that is what I read about it.

But Frex is not yet what I'm looking for. I think it could be better.

See you later.

Quote from Speed Soro :

What you feel when you move? Inertial force on your body.
The direction of this force (and you feel just one, as a resultant vector of the various), is never sending you to the sky, except when you guide your car to the abyss...

Although your intentions are laudable, and I really hope you can make it happen, I can tell by what you write that you don't have a firm grasp on what it takes to make a motion simulator.

Maybe there is only one vector at a time. But how do you define that time slice? 1Hz? 2Hz?10Hz? You are only thinking linearly if you think that you can just apply one force to simulate the car in a corner. What about transitions? Left to right, brake to accelerate, that kind of thing? What is the position of the platform when these things occur? Don't you think that "bull ride" up and down motion is necessary in transition when forces change and you've already leaned the platform as far as it will go in one direction?

Anyway, best of luck, but I suspect you have a lot of learning to do.

What you suspect is exactly what I don't suspect: I have sure

Because that I will start with less.

But one thing is right for me: by the videos, I can't see a real reaction of the driver to what is going on the simulator.

I can't see this up/down thing to simulate back/forth move.

There are lots of motion sims on the market. Rich companies, like car manufacturers, build linear and wide simulators to achieve the same sensation that a real car gives.

6DOF sims are more used by flying companies, and that is another situation.

I think we can reach much better immersion without expent too much, with just feel adds to the cockpit.

That is what I'm looking for. I think you all still don't understand my point.

See you.

How exactly are you planning on simulating pressure from the seatbelts under braking without tipping the cockpit? Unless the cockpit is moving forward and braking (as a real vehicle would) the only force you CAN use is gravity, which is exactly what the FD rig does. You obviously don't understand the forces and the way your brain perceives them. Tilting forward only feels like tilting forward when you have a visual reference to confirm that. If your only visual reference is what you see on the screen (car slowing down) then the tilting forward motion will feel like slowing down, it won't feel like tilting forward. That is why you turn off all the lights - so you don't have the visual reference to tell your brain otherwise.

Maybe it's a language barrier thing, but it doesn't seem to me like you completely understand the situation - or the complexity. You seem overly sure of yourself which is often the cause of failure.

I think that, no matter what route you take, its difficult to pull much over 1g, and therefore you wont get as realistic as real life. I dont know for sure, but I am guessing that force dynamics tries to compensate for this by giving you a wide range of movement. But saying you dont like the way it looks without having actually tried one? Im not sure that's the right approach to making a motion rig. Considering its motion were talking about here, itd be wise to try to test some actual motion through feel rather than eyesight alone.

Im not saying that force dynamics is great, bad or indifferent, simply because Ive never tried it. but one things for sure, i would sure as hell like to try one.

Now, onto a cheaper method? this guy built one out of pvc pipe and windshield wiper motors. browse through the site, hes got alot of how-to's, and videos. THough he built it mainly for flight sim, he also has vids running LFS with a wheel on it.
http://www.motionflightsim.eu.tp/

Quote from RobbyMac :

I think that, no matter what route you take, its difficult to pull much over 1g, and therefore you wont get as realistic as real life. I dont know for sure, but I am guessing that force dynamics tries to compensate for this by giving you a wide range of movement. But saying you dont like the way it looks without having actually tried one? Im not sure that's the right approach to making a motion rig. Considering its motion were talking about here, itd be wise to try to test some actual motion through feel rather than eyesight alone.

Im not saying that force dynamics is great, bad or indifferent, simply because Ive never tried it. but one things for sure, i would sure as hell like to try one.

Now, onto a cheaper method? this guy built one out of pvc pipe and windshield wiper motors. browse through the site, hes got alot of how-to's, and videos. THough he built it mainly for flight sim, he also has vids running LFS with a wheel on it.
http://www.motionflightsim.eu.tp/

Yeah, here's the video(I couldn't get to that site correctly)

http://www.youtube.com/watch?v=7mzbrOhtx4A

I think that guy has the right idea for a somewhat affordable motion simulator. Honestly, I could see myself saving up money for one if he sold them.

Im not sure whats up with his site. It didnt used to ask for password and username, but if you click the close x a gazillion times, the username password window finally goes away.

Maggot, I didn't understand when you said:

"You obviously don't understand the forces and the way your brain perceives them."

You are talking about me or what?

If you are talking about me, I'd like to know from where did you figured out that.

But, the fact is, I understand very weel the forces and the way my brain perceives them.

Let me see if I can make YOU understand my point:

1 - I don't like the way FD makes the things, even without tested it, ever. I base my point of view just by the videos. My critics is about to use the gravity force in a way to agressive to simulate inertia forces. Pay atention: going forth or back, is kind different of going up or down. When you brake and sudenly and suddenly accelerate, the simulator does a fast movement down and up, and this movement is just a mechanic bull. We got a kick from the seat, and this is not natural. You, please, look to that video. See how the head of the driver shakes in a unnatural way. I think something like this will tire you soon. That is not what I expect.

2 - I don't want a perfect motion sim. Did you read this? I DON'T WANT A PERFECT MOTION SIM. Hope you got this point. That said, watch the sequence below.

3 - I'm not talking about 20 thousands dollar cockpit. Neither 10K. I'm talking something around 2 or 3k. It is cheap, and that is what I want. It sales.

4 - I want to build something that, more than a static seat, give some add to the game. A small lateral movement (something around 15° each side), and a small longitudinal movement (something around 10°).


Well, lets jump some parts, and go straitgh to an idea that I was thinking about.

When we brake, our body intent to go ahead, and we support some part of the weight using our hands, our arms. The same occurs when we accelerate, and we sustain a part of the weight holding tight the steering wheel.

So, I was thinking, it is just an idea, and I'd like to discuss it. If I have a way to reduce or extend the distance between the steering whel and my seat, I would realize that something is happening. If the wheel goes away, probable I'll think that I'm under acceleration. If the wheel comes to my direction, I'll think that I'm under brake.

But this movement must to be very small. Just some milimeters, enough just to cheat your brain.

This is the beggining of the idea. Thera are more things to be explaned, but I think it is enough to drop something about it.

Think about, please.

Quote from Speed Soro :

So, I was thinking, it is just an idea, and I'd like to discuss it. If I have a way to reduce or extend the distance between the steering whel and my seat, I would realize that something is happening. If the wheel goes away, probable I'll think that I'm under acceleration. If the wheel comes to my direction, I'll think that I'm under brake.

But this movement must to be very small. Just some milimeters, enough just to cheat your brain.

This is the beggining of the idea. Thera are more things to be explaned, but I think it is enough to drop something about it.

Think about, please.

My thought is that when you are strapped into a race car, your body isn't going anywhere relative to the wheel. Also when you accelerate the wheel does not move away even in a road car, because there is a seat stopping you from going anywhere. I just can't see this tricking your brain into thinking you're accelerating or decelerating. What makes you think you can trick your brain better than the FD system which is applying real, actual, gravitational forces to your body?

Quote from Speed Soro :

1 - I don't like the way FD makes the things, even without tested it, ever. I base my point of view just by the videos. My critics is about to use the gravity force in a way to agressive to simulate inertia forces. Pay atention: going forth or back, is kind different of going up or down. When you brake and sudenly and suddenly accelerate, the simulator does a fast movement down and up, and this movement is just a mechanic bull. We got a kick from the seat, and this is not natural. You, please, look to that video. See how the head of the driver shakes in a unnatural way. I think something like this will tire you soon. That is not what I expect.

A real race car is not a pleasant ride.

Quote :

2 - I don't want a perfect motion sim. Did you read this? I DON'T WANT A PERFECT MOTION SIM. Hope you got this point. That said, watch the sequence below.

This is where we started to deviate in our way of thinking, I think. So, you're looking for something that more gives you a little bit of impression of movement rather than a large range? Now it's starting to make more sense.

Quote :

4 - I want to build something that, more than a static seat, give some add to the game. A small lateral movement (something around 15° each side), and a small longitudinal movement (something around 10°).

Ah.. I had gathered from your other posts that you were intending on lateral movements, not rotational movements. This makes much more sense, now, and I think I know what it is that you are intending to do - mechanically.

Now I get it. Mis-interpretation on my part.

speaking as a FREX SimConMotion owner and with pretty good understanding of motion and the different systems.

ForceDynamics does not always reproduce G-forces felt on the body but on the car meaning if the car banks down 2 degrees FD will go down 2 degrees + X number of degrees for you to feel gforces. This motion gives you a good feeling of what the car is doing. Seeing as how close FD are to the people at watkins glen and the awesome reviews I think you are a bit too harsh on them even without trying a motion sim before.

My frex SCM however produces only G-forces felt on the body less realistic than the FD but its 1/25th the cost. When the SCM pushes me foward and my body is now 4inches closer to the wheel, I know its not realistic but you learn to trick your mind into thinking its braking, you adjust and soon. Trust immersion will be there and sooner or later you will forget it.

By looking at FD videos I will tell 100% that its better than SCM cause knowing how my SCM works.

Quote from Speed Soro :

But this movement must to be very small. Just some milimeters, enough just to cheat your brain.

This is the beggining of the idea. Thera are more things to be explaned, but I think it is enough to drop something about it.

Think about, please.

I've thought about making a similar device myself wanting something that is more compact and less desturbing to the household. I can not imagine a FD301/401 setup in any "normal" persons home even if it were cheap

What I would like to see is a simple, cheap device that gives you "seat of pants" cues which will add to imersion and give more natural feedback loops to the brain about what the car is doing. I can relate to your idea of moving the seat in relation to the wheel/pedals to fool the brain about forces/motion and think it has some good possibilities.

Ideally for my way of thinking it shouldn't be trying to simulate all or even most motion or forces in a race situation but just the important cues that a driver might percieve in different circumtstances (like understeer/oversteer/locked brakes etc.)

Hmm, to me all this is a bit too much actually - probably it just makes me slower I could use the shifter on my G25 - it would be more realistic and more immersive. I do it sometimes for fun. But I lose a second/lap. Paddles are just quicker.

Same if I bounce around in some sort of sim machine reproducing gforces and god knows what. Sounds and looks like fun at first. Once I go a second/lap slower the fun would stop for me pretty quickly and I'd probably switch it off ... lol

I do use FFB even tho some say it makes you slower - I like it and it makes me feel more immersed, but I think that's about as far as I go...

Also imagine a 5 hour session in one of those things, I'd come out black and blue

aceracer

Quote from Speed Soro :

My critics is about to use the gravity force in a way to agressive to simulate inertia forces. Pay atention: going forth or back, is kind different of going up or down. When you brake and sudenly and suddenly accelerate, the simulator does a fast movement down and up, and this movement is just a mechanic bull. We got a kick from the seat, and this is not natural. You, please, look to that video. See how the head of the driver shakes in a unnatural way. I think something like this will tire you soon. That is not what I expect.

This is not so easy to spot on a video what's wrong or right with a motion simulator. What looks first like strange, unrealistic movements, often appear to be very well done.

When you accelerate/brake, the FD tilts backward/forward until the gravity pushes the body backward/forward.
And the location of the center of rotation is very important, but it is difficult to explain (with my english).

If the platform is tilting forward/backward around a low center of rotation (like blue tiger simulator), then it causes conflicting acceleration cues during the movement. Imagine you accelerate, the platform tilts backwards around a low center of rotation. Picture it. The wheel and seat are moving toward the back in user perspective. This feels not like accelerating but like braking...wheel is pushing backward against hands.
But once the backward tilted position is reached and the platform stops moving, you feel the gravity pulling you backward like an acceleration. And this is right.
->we have conflicting acceleration cues.

Now imagine you accelerate and the platform tilts around a high center of rotation, above head, this time forward. Wheel and seat are moving forward, seat pushes against your back and wheel pulls arms, like in real accelerating vehicle. And once the tilted position is reached, the gravitu is pulling you backward like in accelerating vehicle.
-> acceleration cues are coherent.

FD is one of the very rare motion platforms that rolls/tilts around a high center of rotation to avoid conflicting cues. When they tilt/roll the platform they ad the exact up/down movement needed to have a high center of rotation.

So this up/down movement which looks strange for you is in fact very carefuly engineered to avoid conflict between proprioceptive (muscle) cues and inner ear cues.

Here guy from FD explains this very important point a lot better than me:
http://www.youtube.com/watch?v=ghncbQVCQVM

If you tilt/roll someone and translate a little bit at the same time in a very precisely calculated way, you can fool completely the inner ear, the person will really think she is accelerating in a straight line. This trick is the base for stewart platforms, most military motion simulators, big entertainment motion simulators...etc.

Don't forget that these rigs make use of jerk, the rate of change of the rate of change of rate of change of position (or the rate of change of acceleration, or the rate of change of the rate of change of velocity).

Whilst a sustained force of 1G in any direction is the limit due to gravity, the sensation of much more G forces can be had by jerking the driver about (but not off).

Well, I think now we are understand each other

I don't know if this idea I have will really work, but as said before, maybe you can train your brain to associate the aproximation to the controls, as braking, and the separation, as accelerating.

Important: the movement should be just some milimeters, maybe 10 or 20 at maximun. When driving you wouldn't have more than that.

I think Frex movement is to extense. Since first time I saw a video years ago I thought that was not realistic, because it try to simulates the inertial force pushing your body forth and back, but it is not connected to the controls, forcing a strange situation where you can cleary see on the videos the big variation of distance between the driver and the wheel.

FD, by its side, has a better approaching, and that is a old and reliable solution (I think that Boeing was the first to make such system, I have no sure), but, under my vision, this system fits better with Flight Simulator than LFS or other racing game, because the transitions of a plane is always slower than a car, and then, that "mechanic bull" behavior is less evidenced.

I know, some of you have said it to me, and I knew you would do that, but believe me, I already knew that I have not much property to say something about FD, without have tested it. But what I can see on the videos, and what I can think about the system, is something with high probability of be wrong, in certain aspects.

The word is transition, as mentioned by Hallen before, is something that I suspect of FD. Suppose that you are in a flat street, like Autocross. You play with the accelerator, making a series of little taps on the pedal. Your car goes forward and stops, goes and stops, goes and stops. This causes inertial forces over your body, relatively big, and you feel it, but you know you are on the flat, not just because your eyes can see it, but because your labyrinth feels too, and send that information to your brain. But in FD you seem spun in the air, you see on the videos that the body rolls, like the mechanical bull, and I can suppose that it is not too right.

Ok, let me explain something, it is important: I have no intention to talk about FD anymore here. The unique reason that I talked about it, and put those videos for comparison, was to let well clear why I intend to try another approaching. So please, before someone think I'm here for bash the FD, I'd like to let very undertood that NO. I have nothing agains this company, I don't know anyone inside there, and me, being a industrial designer, have too much admiration by their products, their engeneering looks to be stupendous. Ok?

I'll back later to discuss more about my concept. What I want here is to make a brain storm with people who know what a simulator is, in the intention of achieve something more consistent, before start the prototype. And I also intend to make a step by step follow up here to share all experience.

See you later.

I just posted and see another post from you all, and go and see the FD video where he explain what they intend to achieve, but I think they are still far from the solution, cause they cant simulate horizontal movements.

I have something that I think is a solution for this, and i'll try to explain without any picture and with my poor English (God help us):


1 - My idea is way to expensive, so I'll just put it here, but I have no intention to develop it, at least not for while.

2 - Imagine you can move your seat horizontally, along the longitudinal axis, because it is set on a base running over trails. These trails can be linear ball bushing, ok? So you have one base running forward and back, and this is moved by a linear actuator, which can be a pneumactic or electric cilinder, or a ratchet gear, or cables, whatever.

3 - This base, and the support that sustain the trails, are all over another base with longitudinal and lateral movement, something like FD or any other motion sim on the market.

4 - Well, the idea is, the big acceleration, the "kick", would be made by moving the first base, horizontaly, while the slow acceleration (the inertial force that remains while the car is under acceleration), would be made by the inclination of the second base.

5 - I don't know If could paint the idea, but I think it would solves the problem that I see with FD. Maybe a trails 1 meter long, 0,5m forward, 0,5m back, would be enough for that.

6 - While the inertial forces are reduced, the actuator pulls the seat back to the centre at same time that inclination decrease. If you play with the pedals, like I said in the post before, tapping the accelerator, the linear actuador would do the biggest part of the job, and the reaction will be much more realistic.

Quote from Speed Soro :

What I want here is to make a brain storm with people who know what a simulator is, in the intention of achieve something more consistent, before start the prototype.

That's why you need to understand this: what looks right is often not what feels best. Motion simulators HAVE to trick body and brain. They HAVE to do very strange things to make you believe you turn hard in a car at 100 km/h while you are almost not moving at all.

Quote from Speed Soro :

I think Frex movement is to extense. Since first time I saw a video years ago I thought that was not realistic, because it try to simulates the inertial force pushing your body forth and back, but it is not connected to the controls, forcing a strange situation where you can cleary see on the videos the big variation of distance between the driver and the wheel.

Frex is not simulating the acceleration forces on the body. Frex works the same as your idea. It simulates the action/reaction between your body and wheel/pedals.
It makes you feel like the wheel is pulling your arms when you accelerate, and pushing against your hands when you brake. To do so it moves your body backward/forward instead of moving the wheel like in your idea, but it gives the same result. The range movement can of course be decreased, but it seems it feels more realistic when it moves more than IRL, because you have to compensate for missing cues in the inner ear.

Once again, what looks right (10-20mm movement) is probably not what feels best.

edit: your last idea is a motion simulator with rotations+translations. More expensive simulators than FD work like that. Often they use Stewart platforms because it is a very compact system allowing all rotations and translations.
http://en.wikipedia.org/wiki/Stewart_platform

Look at this one sirocco 40 degrees rotations, 60cm translations
http://www.symetrie.fr/Ressources/Files/SYMETRIE-sirocco.pdf

Imagine this one:
http://www.symetrie.fr/Ressour ... ge/l_hexapode_aquilon.jpg

Thank you Julls for the links.
Stwearts does not does translations, not at the same degree I suggested.
The unique way to achieve what I think would be satisfatory, is mounting a plataform like that on a linear plate with wide movement.
Well let me go to my work.
See u