Non-probablistic Robust Optimization Design Considering Uncertain Parameters Of Compliant Mechanism

Uncertainty,existing in the practical engineering problems,may have a great effect on the product robustness,especially in some high-tech fields,such as MEMS,aerospace and biological engineering.Uncertainty factor on the impact of product performance robustness may result in the failure of the product,even cause serious economic losses.Just like cell injection in bioengineering field,the precision and sane request of some related tools should be high,including syringe,gripper and so on,test failure will be caused by slight errors.Therefore,the uncertainty in engineering problems should be considered by designers during the design phase.A large number of sample data are needed to deal with the problem by using uncertainty probability method,and the optimization is completed on the basis of assuming the parameters follow some distribution.There is insufficient data in practice,so the optimization is difficult to implement by using probability method.Aiming at the above problems,the uncertainty robust optimization is studied by more and more domestic and foreign scholars,the non-probabilistic robust optimization was further exploration on the basis of parameter uncertainty.a uncertainty problem of compliant mechanism is taken as an application example to verify the feasibility.The main contents are as follows:(1)This paper adopts a kind of non-probabilistic robust optimization based on evidence theory to deal with uncertain engineering problems with only design variable parameters and the nominal value falls in the interval probability.the process design of non-probabilistic robust optimization is given for the problem of parameter uncertainty in small samples combining with the evidence structure theory,the design of right circle flexure hinge is taken as an example to illustrate.(2)In order to deal with uncertainty engineering problems of considering objectives robustness,constraints robustness and no explicit function between performance and design variables.The objective function,the constrain of equality and inequality are defined with this way,then the model of double robust optimization is established based on non-probabilistic interval,and the process of optimization is provided.The weight is determined by using method of the grey entropy weight considering the case of average and volatility.(3)This paper constructs non-probabilistic robust optimization design model based on reliability constraints to solve the uncertain problems of design parameter scale,structural reliability constraints and explicit relationship between design variables and responses.Based on the method of double robustness optimization model of non-probabilistic interval,a robust optimization is carried out for flexible hinged minute-displacement of piezoelectric actuator micro clamp.The parameter uncertainty’s influences on the average and volatility of the flexible hinged minute-displacement can be obtained by quantitative analysis,which assures the performance of flexible hinge satisfying the requirement of engineering design considering the case of parameter uncertainty.(4)This paper uses a lot of kinds of non-probabilistic robust optimization design considering parameter uncertainty problems in engineering.With the case of compliant mechanism from micro piezoelectric actuators clamp,the method is verified and optimization results show that it has a good application prospect.