图1为万向轴的原理图。按照单个万向节的运动学,1轴的均匀转速随着折角β的大小而转变为2轴的不均匀转速。这种不均匀性使得2轴转角α_2呈正弦曲线状地超前和落后。因此1轴转角α_1和超前或落后的2轴转角α_2之间出现一转角差Δα。给定万向节的折角β,在任何1轴转角α_1下的转角差Δα的变化按下式计算: Figure 1 for the cardan shaft schematic. According to the kinematics of a single universal joint, the uniform rotation speed of one axis changes into the non-uniform rotation speed of two axes along with the size of the bending angle β. This inhomogeneity causes the 2-axis angle α_2 to lead and fall sinusoidally. Therefore, a rotation angle difference Δα occurs between the 1-axis rotation angle α_1 and the leading or trailing 2-rotation angle α_2. Given the knuckle angle β of the joint, the change in the angle difference Δα at any 1-axis angle α_1 is calculated as follows: