Based On The Robust Design With Accuracy The Probability Of The Gap Linkage Analysis

Planar linkage mechanism is used broadly in many types of machinery. Because of the innate reasons in structure, there is always structural error in the output motion. Besides, the manufacturing error, clearances at joints, and input error also bring mechanical error. The factors leading to mechanical error are probabilistic variables in general, so the outputs of linkages are probabilistic ones too.In the dissertation, based on the robust analysis and design method, which regards the input error and structural error as probabilistic variables, and structural error, clearance at joint taken into account, robust analysis and design about linkage mechanism is researched at last.Manufacturing error considered, probabilistic errors about kinetic and dynamic parameters for rigid linkage mechanism are analyzed. Probabilistic error analysis models in matrix form about kinetic and dynamic parameters for linkage are established, which avoid complex mathematics operations when the output expression is differentiated directly, and resolve the pertinence between the errors of the output parameters of mechanism.Based on the continuous contact model, the clearance at joint is treated as a rigid straight linkage, which has no mass and its length equals to the radial clearance. Using Lagrange function, dynamic function about mechanism is developed and numerically integrated and so the clearance angles are gotten. Through the continuous differential to the output and input expression, a general expression about kinetic parameters stated in matrix form for mechanism with clearances at joints is formed. Furthermore, the influences of the number and size of clearances and the rotate speed of crank to the kinetic responses are analyzed.Considering the randomicity of errors causing mechanical errors, and statistic and stochastic theories used, probabilistic error analysis models about kinetic and dynamic output parameters for planar linkage with clearances at joints are established. The models provide a quantitative yardstick for fixing on the errors of linkages and clearances, analyzing the effects of clearances and appraising the accuracy of mechanism, and are important to improve the reliability and the longevity of mechanism.