Importance measure of revolute joint clearance about motion accuracy of linkage mechanism

In order to study the contribution of the joint clearance uncertainty on the output error uncertainty of mechanism, a gear 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.