说明：  汽车bai的7自由度模型du一般是在设计汽车悬架时用zhi到，1/4悬架时2自由度模型，包括簧上部分的dao垂直运动和簧下部分的垂直运动，半车悬架是4自由度模型，整车用7自由度模型。考虑汽车悬架作用，这车车身有三个自由度，分别是车体的Z轴上下运动，沿X轴和Y轴的转动。对于空间刚体6个自由度中的其他3个自由度，2个平动和转动与悬架系统无关，所以没有考虑。上述3个车身自由度加上4个悬架的簧下部分(主要是轮胎的上下跳动)，一共是7个自由度。
(The 7-DOF model Du of automobile Bai is generally a 2-DOF model when designing automobile suspension, including the vertical movement of Dao on the spring part and the vertical movement of the under spring part. The half car suspension is a 4-DOF model, and the whole car is a 7-DOF model. Considering the function of automobile suspension, the car body has three degrees of freedom, which are the up and down movement of Z axis of the car body, and the rotation along X axis and Y axis. For the other three of the six degrees of freedom of the space rigid body, two translation and rotation are independent of the suspension system, so they are not considered. The above three body degrees of freedom plus the four suspension spring parts (mainly the up and down runout of tires), a total of 7 degrees of freedom.)