Stability with JointSuspension

[p.vaz]

Hi,

 

In Unigine script, I'm tring to create a vehicle with 4 wheels using 4 JointSuspension, but I enconter a problem : I encounter a lot of jittering, the vehicle doesn't stop to bounce on the ground. For information, my vehicle has a mass of 1000 and each wheel (a sphere shape) has a mass of 20, (ratio of mass_vehicle / mass_wheel = 500). 

 

I've tested also in your car_00.cpp physics demo, I've noticed that the body of the car has a mass of 64 and the wheels a mass of 33.5 each (ratio of almost 2). When I reduce the mass of the wheels (3.3 for example) for a ratio of almost 20, it begin to bounce.

 

How can I have more stability with JointSuspension ? 

 

Philippe

[binstream]

Do not try to apply real physical parameters to joints - it will not work. In order to get a stable vehicle, keep masses of all parts within the same range.

[p.arrighi]

Hi binstream,

 

it is quite surprising that real physical parameters doesn't work with joints in a simulation engine. Since we can't have car's body of 1000kg with wheels of 500kg each, does it means that this link is useless for simulation ?

 

Regards

[binstream]

We never market UNIGINE physics as being physically accurate - it is OK for a lot of visual effects (collision detection, gravity), but not for accurate physics simulation.

If you are building a flight simulator, it is a standard approach to use specialized flight model (special physics engine) for that.

[p.arrighi]

As mentioned in my previous post, we currently manage cars not planes. We don't need spatial agency accuracy, but simply realistic behaviors with realistic parameters.

 

https://developer.unigine.com/en/docs/1.0/principles/physics/

 

"Unigine real-time physics integrates collision detection, fracturing, buoyancy, joints and external physical forces to realistically simulate objects and complex interactions between them."

 

Regards.