I'm developing a vehicle simulator game for mobile platforms. This vehicle has some hydraulic arms. I use hinge joints and configurable joints. There can be collisions to walls etc.
When I set a low Fixed Timestep (more fixed updates, less performance) like 0.001 it runs smoothly on editor and it handles the collisions well. But on the target mobile device, the performance drops to 2-3 FPS! So 0.001 (1000 fixed updates per second) is not an option.
When I change the Fixed Timestep to its default 0.02 value or 0.01, performance becomes acceptable on mobile. But when collisions occur, the vehicle is torn apart and everything flies away at a high velocity as if there was an explosion.
How can I achieve stable physics with 0.02 Fixed Timestep?
Note: I don't set the velocity or transform position. I move the vehicle by applying torque to the wheels.
Update 1 : The problem happens when the vehicle hits an obstacle that has a collider but doesn't have a rigidbody.