Pantograph Kinematic Reliability Analysis Considering the Correlation of Rod Size
In order to analyze the influence of the correlation characteristics of rod size parameters on the motion reliability of mechanism,a mechanism motion reliability analysis method based on Cholesky rule is proposed.Firstly,the kinematic equation of the mechanism is constructed according to the principle of mechanism kinematics.Secondly,combined with the effective length theory,the effective length model of the rod considering the clearance of the moving pair is established.On this basis,the Archard wear model is introduced to quantify the influence of the motion cycle on the effective length of the rod.The sample size data of the rod under different motion cycles are obtained by monte carlo method,and the sample correlation coefficient is calculated.Then,the sample data of the rod under different motion cycles are reconstructed by Aholesky law.Combined with the reliability theory,the motion reliability of the mechanism is evaluated.Finally,the effectiveness of the proposed method is verified by taking the pan-tograph mechanism as an example.The results of calculation and analysis show that the correlation of rod sample data is en-hanced due to the existence of kinematic pair clearance,and becomes more and more significant with the increase of kinematic pair clearance.Compared with the traditional analysis methods,the mechanism motion reliability index based on Cholesky rule has a certain degree of decline,which can provide a safer reference value for the reliability evaluation of practical mechanisms.
PantographKinematic ReliabilityCholesky MethodEffective LengthArchard Model
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