为研究铰链间隙的不确定性对连杆机构输出误差和失效概率的贡献,以舱门机构为例,建立了其多体运动学模型。将机构部件分类为拉压杆和受弯杆,基于"等效杆长理论",建立了运动精度模型和可靠性模型。分别采用针对输出误差和失效概率的矩独立重要性测度方法,对铰链间隙进行了重要性测度与分析,研究了铰链间隙分布参数的变化对其重要度的影响。计算和分析结果表明,铰链间隙均值的变化对重要度影响较小,标准差的变化对重要度影响较大。减小铰链间隙的标准差,能更为显著地降低其不确定性对机构输出误差和失效概率的贡献。
In order to study the contribution of the joint clearance uncertainty on the output error uncertainty of mechanism,agear door mechanism of an airplane was taken as example to illustrate the IM of the revolute joint clearance.Firstly,the kinematic model of the mechanism was constructed. Secondly,the components of the mechanism were classified as two-force bars and bending parts.Based on the"equivalent length theory",the motion accuracy model and reliability model of the gear door mechanism were constructed.At last,with the moment-independent IM method about motion accuracy and failure probability,the IM of joint clearance was emulated under different distribution parameters.From the emulation results one can get that the variance has a bigger affection on the importance value of the joint clearance than that of mean value.