SCN5 Actuator Positioning

Dear sirs,

Please see photo:

It's not set in stone. Yes, the pivot should be where all your weight will be centered, if it's forward, backward, whatever, put it where it takes the load.
The angles are not fixed either. Everybody is using something different. Mine are a little outwards on both sides (5-6 cm to the ouside from the connections at the top) and around 80 degree angle between actuator arms and base.

I see you got banned from racesimcentral.

Fahim,

I do not think that we have discovered the best working range yet as a community. There are alot of factors that are not consistent among everyone's motion base design. For example, I have seen various choices in rubber mounts, u-joints, seat weights, varying seat center of gravities, various seat-back angles, various pivot point locations, various choices in ball joints, various upper-seat mounting points, etc.. As a quick example, I use a very upright real race car seat from Sparco in one of my designs, and a race-car style seat that has a slightly more reclined seat in another design. This slight variation effects the pivot point location. Therefore Shige's comment cannot be correct for all seat scenarios since undoubtedly, the seat back angle effects the balance point.

With regard to angles, the 100mm actuators are much more forgiving (I have seen them mounted in many different configurations) of these dimensions because they do not move the drivers weight as far off of the pivot point as a 150mm actuator would. A 150mm actuator will achieve greater side-to-side lean and therefore require a more agressive angle. A 150mm actuator will also require a more precise answer to the question of angles. The X-axis is never an issue on it's own in my experience. Positioning for Y-Axis leverage is most important, but if you over-do this, you will suffer under scenarios where you are mixing maximum X-and Y axis values and one actuator has to lift on it's own. (Ex. Heavy braking in a high g-force left hand corner will cause the left actuator to be fully extended and the right actuator 50% extended. If you maintain braking, but come out of the corner, the left actuator has to lift your weight on it's own back to the center point from this extreme if your profile is configured to mix axis!

Also, this is somewhat dependent upon your choice in software settings. If prefer a higher acceleration value than most because I want to feel more road surface effects and because a lower acceleration value produces unrealistic collision effects. This high acceleration value allows me to lower the actuator speed value and still achieve a realistic effect. The higher acceleration value also gives me an improved braking ramp. Altogether, the actuators are not moving quite as fast, and have a higher braking value which helps improve actuator strength and reduce momentum. As you can tell from my videos, these settings achieve a realistic effect.

However, other folks prefer tuning in the opposite manner by using 100% speed and reducing the acceleration value to a lower number. They will require a near-perfect actuator angle in order for there to be enough braking strength.

For my original design, I had to compromise the best actuator angle due to dimension limitations of the simulator that I am ijnstalling the motion base in. I have achieved fuctional, but not optimal angles. I am still working on finding the best actuator angles. I am making a new test platform next week that will allow me to conduct further testing at greater angles. I will post back when I have a more precise answer to your question, but due to the many variables, I cannot ensure that my angles will be optimal for your design.

Dear sirs,

I had fight with moderator called james burguss: I said to him that he should not have banned one of the people from there:
He told me to leave the business to him, but I thought he was unfair to the person so i said to him:

James Burgoss,

I find you guilty.

Happy new year.

I said this and it made him very angry and he banned me1 month. Thats what happen when you try and help somebody

Kind regards.

Yes, this is the point of most stress because one actuator has to pull the drivers weight back to center, while the other actuator is pushing (inverted). In almopst every other scenario, bothactuators are pushing / pulling at the same time, or at least have mixed instructions (combined acceleration and cornering) so in part, both are pulling as well.

It takes bad driving or a crash to create this scenario in the game. It is best to test these combined scenerios via the test plugin and ensure that no scenario will exist that the actuators cannot handle. I created a video tutorial on how to do this: http://www.x-simulator.de/forum/post12009.html#p12009

You can't get around it, at some point one will be low and will need to lift you up. But I wouldn't worry about it because people have been using it with frex for years and I never heard of major problems. You do want them to the outside and leaned forward so you create good torque on the seat.

Just ignore that moderator, don't even talk to him, he sold out to frex (which won't listen to you ever).

I'm still toying with my angles. Mine are literally straight up (150mm) when the chair is centered. I have noticed when banking and braking hard, one actuator will compress completely, but at such a high rate of speed that it has a hard time decelerating to the safety zone. I've incorporated a 10% limit on all moves (90% Limitor option) to help reduce any hard stops. But, taking Bernards idea and inserting a rubber gromet may help reduce possible impacts.

Because of the long travel, I have noticed something else. When your full brake and you hit the gas, the chair travels pretty far and fast to the point that you get a nice sensation of accelerating. But, to accomplish the effect, you need some good accel and speed values or else you have to long of a travel on the SCN150mm to pass the neutral point and into the compress (accel) point, which would be less of an issue with the 100mm.

Looking at many FREX's out there, I believe those motors have lasted a long time due to the softer/less travel distance in FREX's design. My design and anyone else who like hard fast movements may begin to experience actuator wear issues sooner I would suspect.

A free-body analysis of a chair+pivot point would be usefull in determine at which point the SCN5s experience the least force. If the SCN5s are strong enough, who cares about angle. I would then position them where ever they allow for maximum travel.

EgoExpress is correct with the above image. Those figures are optimal. Rather than testing while in a game, you can test under some more controlled / predictable circumstances. Here is a video that I made describing how to accomplish that.

For some reason, the quality turned out terrible on YouTube http://www.youtube.com/watch?v=9DBgx60_MSI&feature=channel_page. I posted a hi-res version on my site which you can access from this forum post. Also, a test profile is available in this post as well.

http://www.x-simulator.de/forum/post12009.html#p12009

You're forgetting about sinTheta.

There are quite a few variables to consider.

- Where you attach the SCN5 to the chair with regards to height. (Disregarding the attachment point at the base... lets assume the base attachment is such that your force is perpendicular to the moment arm coming up from the pivot point).
POSITIVE: The higher you attach them, the more torque you get, hence the less force required by the arms to move the chair.
NEGATIVE: The higher you attach them, the less distance your chair will move for the entire 150mm range.

- Where you balance your chair. Our natural intention is to balance the fulcrum such that you can sit in the chair without touching anything else and balance yourself perfectly. Herein lies a few problems. Your weight is not distributed properly at certain chair angles. You normally drive with your feet pushin against pedals and hands holding a wheel. So, if the chair is fully forward (when your braking), the weight that is tossed forward is not as much as you would think since your pushing back with legs and arms.

On the other hand, your upper torso weight has a larger impact when the chair is tossed backwards (when accelerating). If, like me, you like having the chair normally tilting backward to get more of an accelerating sensation, then most of the weight your SCN5s will have to deal with will be in that position. So, you would want to adjust your SCN5 angles to be able to push you back up to neutral from this most severe case.

- Where you attach the SCN5 at the base (angle).
POSITIVE: The further back the base is (larger angle), the closer you get to a perpendicular force vector with respect to your moment arm = more torque = less force exerted by the SCN5.
NEGATIVE: The ideal position will naturally be located way back, making the simulator awkard and reducing your SCN5 travel.

To compensate the negative, the base of the SCN5 should be attached a bit elevated so you don't lose actuator throw.

All of the above can be considered for all four travel directions. To sum it up, every sim is different in dimensions. At the least, you can draw a line from your fulcrum straight to your SCN5 attachment point on the chair (this would be your moment vector). Measure the distance. Now envision a line perpendicular to that line coming off of your SCN5 attachment point. Follow that line to the floor. This would be your ideal base attachment point for the SCN5. All of this is down with the chair in the position furthest back (accelerating) since this is probably the highest load the SCN5 would need to deal with. You can do this for the base position both behind the chair and to the side of the chair. Then, work your way back to make your design small enough to fit in your room, as you'll notice the ideal location is just not practical. If the SCN5s were super powerful and leverage was not an issue, I would mount them as low as possible behind the chair to use as much of the 150mm travel as possible. Since they are weak, we need to mount them higher.

In the end there is not right solution since every design is different. But, you could try offseting your weight forward in the chair (vs. perfectly equilibrium) to help keep the actuators from struggling when fully back in the acceleration position.

Stick with a proven design.

Dear sirs,

You can buy these from B & Q in Uk, OR local hardware shop. It is a part for a cabinet hook.

I was thinking if I can put these on back of a chair then you can maybe attach the actuators to them. They look very neat and made from chrome.

Hi,
do you think it will improve my Wipermotor-Simulator if i change the angle position from the wiperarms like the red stripes in the photo?. Or it is not worth the work

Are you not finding your current setup satisfying. If not, why fix something what's not broke
But the way you draw the red lines. It is how I will do it.
But I am not sure if wiper motors work same way as scn5 actuators.

Yes, the current setup is good, but there is something to improve always 8) .
For example, cars also continuously improved although they are already good .

I never thought of it like that
I always thought, If a football team is perfect and wins everything, then why sell players and get new ones. It may go horribly all wrong

But this is not football, it's cars. Haha.

If we all satisfied and do nothing more, then there would be no progress in Future. 8)