Research On Probability Analysis And Robustness Design Of Planar Path Mechanisms

In the field of mechanisms,the study of kinematic synthesis has been active about path mechanisms.Aimed at accurately or continuous path synthesis,many scholars committed to the research of improving integrated model and solving method.It is to improve the accuracy of kinematic synthesis.In other words,it is to reduce the motion error of the mechanism.However,the above study shows that the kinematic design of mechanism is in the range of deterministic.The uncertainty of the system of internal and external,including manufacturing tolerances,kinematic pair clearance,wear,heat stress deformation,is ubiquitous in the real mechanisms,which has led to a certain deviation on the actual motor output and ideal output of planar mechanism.Meanwhile,it also has a great influence on kinematic and dynamic performance of mechanism.For analyzing and reducing influenceof uncertainty,a probabilistic method has presented to develop the statistical moment analysis and robust synthesis under uncertainty for planar path mechanisms in this paper.Finally,the robust design model is constructed by using the mean and variance of mechanism synthesis motion error.In this paper,the main research work can be outlined as:1.According to the analysis of kinematics and movement performance,and combine with the impact of dimension tolerancevariables and structure error,a model of output motion error for planar path mechanisms is established.Meanwhile,the influence of the output motion error isanalyzed for the randomness of dimension tolerance variables.2.Appling the bivariate dimension reduction method,the formula of statistical moment for the motion error of mechanism synthesis is approximated,and then the mean and standard deviation functions of the motion error are derived.At last,a numerical example is given to demonstrate theeffectiveness of the present method.3.Based on the uncertainty the institutional system inside and outside,the probability designis proceed under considering the randomness of dimension tolerance variables of the planar linkage mechanism.Finally,the robust design model is constructed by using the mean and variance of mechanism synthesis motion error,and the design model of robust and deterministicsynthesisarecompared and analysised through a numerical example.The results show that robustness design method is more advantages than the deterministic design in terms of improve the quality of mechanism design.