Pitch, Roll and Yaw of automobiles

　・In Japanese

■ Pitch, Roll and Yaw are.

Pitch, roll, and yaw refer to the rotation of a vehicle on its central axis when viewed from the side, forward, and top, respectively.



Even in the pitch, when the front of the car drops when decelerating, it is called "nose dive", and when the front rises when accelerating, it is called "squat".

■What is "oversteer" and "understeer"?

Understeer is when the front wheels skid and the turning radius increases due to the addition of a yaw moment as the vehicle speed increases, and oversteer is when the rear wheels skid and the turning radius becomes smaller. Neutral steer means that the turning radius does not change.

■Yaw rate calculation method

＜Steady turning＞
The yaw rate is the amount of change in the yaw angle per unit time, and the yaw rate Y during steady turning can be expressed by the following formula.



The reason for the above formula can be obtained from the following ratio relationship.



Also, if it is transformed into V = Y*R, it can be considered that "turning radius and turning angular velocity multiply to get tangential velocity".

＜Slipping＞
It can be expressed by the following formula.



K is called the stability factor, and it means K when the following holds. When K>0, as the vehicle speed increases, the turning radius increases and understeer occurs, but when K<0, as the vehicle speed increases, the turning radius decreases and oversteer occurs.

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