考虑运动副间隙的函数机构稳健设计

Robust Synthesis of Planar Function Mechanisms with Joint Clearance

机构的随机因素使其运动输出在名义值附近波动,从而导致机构的运动精度和可靠性降低。为降低机构运动输出对随机因素的敏感度,提高机构运动品质,提出一种考虑构件尺寸公差和运动副间隙等随机因素的机构稳健设计方法。首先应用截尾混合降维法建立间隙机构运动误差的概率模型,然后采用田口质量损失函数导出机构运动的质量损失函数,再以此建立机构的稳健设计模型,最后以平面四杆函数机构综合为例,验证其方法的有效性。结果表明,该方法能够有效提高机构运动的稳健性,其设计所得机构的运动误差的平均均值和平均标准差分别比原机构减小55%和25%。

The random factors in the mechanisms make the output of the motion fluctuate around the nominal value. The fluctuation leads to the reduction of movement precision and reliability of the mechanism. In order to reduce the sensitivity of mechanism motion output which effected by uncertainty and improve the quality of mechanism motion,we propose a robust synthesis approach which taking random factors such as links dimensional tolerances and joint clearances etc into account. First the hybrid dimensional reduction method（ HDRM） was used to establish the probability model of mechanism motion error with clearances. Then the Taguchi quality loss function was introduced to derivate the quality loss function of motion of mechanism,and the robust design model of planar path mechanism was established. Finally,the synthesis of planar function mechanism was given to illustrate the effectiveness of the proposed method. Verification result shows that the new design method can improve the robustness of mechanical motion effectively which was proposed in the paper,the average mean and mean standard deviation of motion error of designed mechanism reduced by 55% and 25%,respectively,which were lower than original mechanisms＇.