Multi-objective Optimization Design Of Reliability Of 3-PRRS Parallel Mechanism Considering The Uncertainty

Actually, uncertainties exist in parallel mechanism design process inevitably.They affect product performance. In the field of multi-objective optimization design, uncertainties will spread among the objective function with the coupled variables, leading to result uncertainties cumulative, then affect the reliability of the final result of the design. Multi-objective optimization design and uncertainty have been studied, but because of parallel mechanism modeling difficult and excessive calculate, there is no real research to combine the two. secondly, in recent years,the researches multi-objective optimization design on the parallel mechanism are better, however,the research considering uncertainties in the design of parallel mechanism are little, especially the research on multi-objective parallel mechanism are less. This paper studies the new 3-PRRS 6-DOF parallel mechanism, considering the impact of uncertainty on the design variables,combing the multi-objective optimization design theory with reliability design method to establish multi-objective optimization design of reliability of new3-PRRS parallel mechanism considering the uncertainty. Research work is as follows:First, closed analytic method was used to study all the forward position solutions. Jacobian matrix is derived and variable substitution is used to get the singular trajectory analytic expression, and the computer simulation is used to describe the singular trajectory. Factors affecting the workspace were analyzed,three-dimensional polar coordinate search method was used to program workspace.The influence coefficient method was used to obtain the first-order and second-order effect coefficient and principle of virtual work was used to analyze the inverse dynamic, and Matlab and Adams were used to verify the correctness of the dynamic model.Secondly, the theory of uncertainty were introduced. Probabilistic methods was used to quantitatively deal with uncertainty on multi-objective optimization design of parallel mechanism. Random uncertainties were considered on 3-PRRS parallel mechanism using probability theory of knowledge to establish reliability optimization design models. Multi-objective considering uncertainties reliability design method based on Isight was established.Thirdly, the workspace, global dexterity indicators, linear acceleration andangular acceleration performances were considered, building a multi-objective optimization model. The random uncertainties were analyzed involved in the design and manufacture, Matlab software and Isight optimization software were combined to establish multi-objective optimization design of reliability of new3-PRRS parallel mechanism considering the uncertainty, higher reliability optimal solution was gotten.