The orbit and the vibration of the pin center and the attitude of the axis of pin in the revolute joint are measured by the TD800 test system.

使用TD800测试系统，能够实时地测出转动副轴心的运动轨迹、振动波形以及轴在空间的运动姿态。

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Trailers are typically attached to tractors by a "fifth wheel, " in which a coupling pin on the trailer fits into the center of a large horseshoe-shaped piece of metal.

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