Re: Vehicle configuration

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Re: Vehicle configualtion

Postby Julio Jerez » Fri Feb 20, 2015 6:41 pm

e3dalive wrote:assuming one wheel of the truck is on ice or in mud, you can get the other wheel rotation omega from ground with higher friction, and override original wheel on mud[it's sort of cheat idea but may work]

is this a slip differential you are talking about?
this mean the ratio of the angle velocity of a axel in keep with it 1.0 -+ some tolerance?
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Re: Vehicle configuration

Postby e3dalive » Sat Feb 21, 2015 4:01 am

it's differential lock, it's shown in this game http://www.youtube.com/watch?v=3EfBMNkLDZk
it allows the truck to get out of the mud by locking the rotation of both wheels
here is another video of my drifting(now with back-wheels) http://www.youtube.com/watch?v=iU57S058o5o
i remember you asked what other addition would be nice to add to the newton vehicle, i think ABS brakes system would be nice
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Re: Vehicle configuration

Postby e3dalive » Mon Feb 23, 2015 5:45 pm

here's another video of me drifting at 160kmph and falling over http://www.youtube.com/watch?v=cLQ1kA-orYA
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Re: Vehicle configuration

Postby Julio Jerez » Mon Feb 23, 2015 8:03 pm

Ha very cool, far car an dis no even a sport car.
I think that for a fast car, you nee to make the suspensions a little stronger.
you can make the string maybe 25% strong and shorter, and the damper maybe 10% or more .
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Re: Vehicle configuration

Postby Julio Jerez » Mon Feb 23, 2015 9:29 pm

what is ABS brakes system ?
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Re: Vehicle configuration

Postby e3dalive » Tue Feb 24, 2015 3:28 am

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Re: Vehicle configuration

Postby e3dalive » Fri Feb 27, 2015 5:54 am

i think i found possible bug, when car is moving at 100km/h and wheel is at 0 sometimes it's flicker a little from left to right - this may be because of high mass on spring or maybe something else, what do you think? http://youtu.be/RirKBDNCEFY it's shown from 0:05
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Re: Vehicle configuration

Postby e3dalive » Fri Feb 27, 2015 10:35 am

--
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Re: Vehicle configuration

Postby e3dalive » Mon Mar 16, 2015 9:41 am

is it possible to set friction to wheels directly?
for example i already have friction for scene grass and for scene roads, is it possible to set the friction of wheels themselves, (driving on wet road, driving in snow and on normal road)?
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Re: Vehicle configuration

Postby Julio Jerez » Mon Mar 16, 2015 1:22 pm

the vehicle joint has the a class

Code: Select all
class CustomVehicleControllerTireCollisionFilter: public CustomControllerConvexCastPreFilter
{   
   public:
   CustomVehicleControllerTireCollisionFilter (){}
   CUSTOM_JOINTS_API CustomVehicleControllerTireCollisionFilter (const CustomVehicleController* const controller);

   CUSTOM_JOINTS_API virtual unsigned Prefilter(const NewtonBody* const body, const NewtonCollision* const myCollision)
   {
      return 1;
   }

   CUSTOM_JOINTS_API dFloat GetTireFrictionCoefficient (const CustomVehicleControllerBodyStateTire& tire, const NewtonBody* const body, const NewtonCollision* const myCollision, dLong contacID) const
   {
      //return 1.5f;
      return 1.0f;
   }

   const CustomVehicleController* m_controller;
};


after you create the vehicle, you can set you own contact filter by calling
void SetContactFilter(CustomVehicleControllerTireCollisionFilter* const filter);
and overload function
virtual dFloat GetTireFrictionCoefficient (const CustomVehicleControllerBodyStateTire& tire, const NewtonBody* const body, const NewtonCollision* const myCollision, dLong contacID) const

Sync I forget to make that function virtual.
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Re: Vehicle configuration

Postby Julio Jerez » Mon Mar 16, 2015 1:25 pm

maybe function
dFloat GetTireFrictionCoefficient (const CustomVehicleControllerBodyStateTire& tire, const NewtonBody* const body, const NewtonCollision* const myCollision, dLong contacID) const

does not pass the contact itself, maybe I can add that as a parameter so that you can get more detail information of you want.
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Re: Vehicle configuration

Postby e3dalive » Tue Mar 17, 2015 3:47 am

i guess it's not possible to set nwmaterial to tire directly.
i will try your functions thank you
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Re: Vehicle configuration

Postby Julio Jerez » Tue Mar 17, 2015 10:17 am

what will serve as eh material will be that class.
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Re: Vehicle configuration

Postby e3dalive » Tue Mar 17, 2015 11:04 am

thank you, i got it to work
here's the video http://www.youtube.com/watch?v=BqLEv0YAsIM
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Re: Vehicle configuration

Postby Julio Jerez » Tue Mar 17, 2015 2:00 pm

Ha very cool.
I really have to make time to add the close loop assistance for Yaw Rate and Side Slip Angle Control.
at the moment the simulation is an open loop, that does not simulate the slip angle state variable.
I have read many papers on the suget but I have not implemented yet.
here are some examples.
http://soliton.ae.gatech.edu/labs/dcsl/ ... vas09R.pdf
http://www.control.lth.se/documents/2002/5697.pdf

Essentially the side slip is a state variable with its own independent differential equation
that need to be integrated alone with the rest of the other state variables.
not doing that make hard to control.

I started to doing few weeks ago, but them I was busy at work, but I see if I add more work these weekened.
I saw the Bus video, and it is nice but to me even in a snow road the vehicle should be more controllable. This is not your fault, it is all mine. That important variable is not taken into consideration.
to make an analogy is like try to do a planetary simulation and ignoring the law of gravitation.
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