cosmos setup brake pedal

[ERT]

hi
Was just trying to analyse the brake pedal forces on cosmos. what restraints and forces should i use. should i apply the force from your foot. then have the pivot part of pedal restrained like a hinge or fixed. same with the pick of the balance bar should that hve a force or fixed.
Help would be great thanks. I understand the forces on the peal just puting it on the computr is harder.

[ERT]

hi
Was just trying to analyse the brake pedal forces on cosmos. what restraints and forces should i use. should i apply the force from your foot. then have the pivot part of pedal restrained like a hinge or fixed. same with the pick of the balance bar should that hve a force or fixed.
Help would be great thanks. I understand the forces on the peal just puting it on the computr is harder.

[Juan Piñeiro]

well in my opinion force being applied to the pedal by your foot and force going to the balance bar/master cylinders should be treated as known variables if you did analyze your brake system. What I do (any suggestions are welcome) is to put a fixed restraint on the pedal pivot, the force applied to the pedal (the amount of this force is another story... search the forums) and the output force where the spherical bearing from the balance bar would be. This force should be the applied one multiplied by your pedal ratio.

[billywight]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">the pedal by your foot and force going to the balance bar/master cylinders should be treated as known variables if you did analyze your brake system. What I do (any suggestions are welcome) is to put a fixed restraint on the pedal pivot, the force applied to the pedal (the amount of this force is another story... search the forums) and the output force where the spherical bearing from the balance bar would be. This force should be the applied one multiplied by your pedal ratio. </div></BLOCKQUOTE>

Look at how it works in real life and model it that way - put the force at the foot pad, hinge restraint at the pivot, and restrain rotation at the balance bar location (use a reference geometry restraint).

[ERT]

thanks for that. i originaly tried the first idea but then change to the hinge. thanks for all the help.

[Juan Piñeiro]

I got the suggestion/correction I was looking for http://fsae.com/groupee_common/emoticons/icon_smile.gif but what I didn't understand was the restrain in the balance bar, the part of use a reference geometry restrain, Billy if you could explain this a little further... Thanks http://fsae.com/groupee_common/emoticons/icon_biggrin.gif

[billywight]

In Cosmos, the reference geometry restraint essentially creates a coordinate system that references a certain geometrical feature that you assign. You can then constrain degrees of freedom with respect to this coordinate system (it is doing all this behind the scenes, which is one reason why I don't like Cosmos so much...). In your case, when you create the restraint, select "use reference geometry" (or something similar) as the type of restraint. Pick the pivot axis of the pedal (or cylindrical bore) as the reference geometry. This will create a cylindrical coordinate system about that axis. Then constrain the faces that the balance bar attaches to in the degree of freedom of rotation. Hope this helps.