The error of the model value comparing to the experiment value is less than + 20 % and - 15 % 模型的预测值与实验值的上偏差在20以内，负偏差在15以内。
3.
It is the first time to define the tolerance with upper deviation smaller than lower deviation as virtual tolerance which is given in this paper as well 摘要把上偏差小于下偏差的公差定义为虚公差，探讨了虚公差存在的理论基础及其意义，从而丰富了公差的内涵而发展为广义公差，更适合计算机辅助公差设计。
