Thank you everyone.
I have solved this problem by removing "G-00 Hinge".
I tried to use this part to connect the wheels to my vessels in order to make it foldable.
I am not sure if this is a bug or I missed some adjustments.
My playing version is
1.9.1.2788(WindowsPlayer x64) zh-cn
1.9.1 Making History
1.4.1 Breaking Ground
I am trying to dock my mining vehicle to a landing ship on Mun. However, after a successful docking, it starts to "jump".
Here is the video:
https://youtu.be/dKNikw3ewYU
Can anyone help me please?