Robot model slides when spawn

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Hi all,

I am creating a 4 wheel front-steered model. However, my model tends to slide to one side each time I spawn it. To give you the illustration of the problem,

I have attempted (but failed) several solution as follow:-

1. Change the moment of inertia parameter for the chassis. (This only make the slide slower. But it didnt eliminate the issue)
2. Change the fdir
3. Change the kp value of the joint
4. Add mu constant to the surface
5. Update to Gazebo 9.13.1

I think there is some parts that I did wrong, or I misunderstand the solution given by others in this Gazebo Answer. Thus I appreciate it if you could point me to the parts that I did wrong. I have added the urdf to my git repository. I thank you in advanced.