| Machine tool,as a modern complicated producing tool,is one of the most important elements of production.To some extent,technology level of the numerical control machine tool stands for the industry modernization level of the country.Power tool turret is oneof the core function unit in the multitasking lathe and lathe-milling machine center.Inthis dissertation,based on computational intelligence and reliability analysis methods,the generalized optimization of power turret with related components are investigated.The main research of the dissertation can be briefly described as follows:(1)The evolution of power turret technology,the manufacturer's turret type and thecommon collocation type between turret,multitasking lathe and lathe-milling machine center were introduced briefly.(2)With reference to the low accuracy of local exploitation in standard particleswarm optimization(PSO),this article combines PSO and the polynomial mutation op-erator(PMO).PMOPSO method is supposed,which is the PSO method with polynomial mutation operator.In PMOPSO method,polynomial mutation operator is used for ex-ploitation.Current point is updated by Metropolis rules.The constraint handle is penalty function method and 'hit wall' method.In numerical examples,PMOPSO method inher-its the powerful earlier global search ability of standard PSO.At the same time,PMOPSO method has a good ability of late local exploitation.(3)On the basis of importance sampling theory,combining penalty function methodsin the optimization theory and PSO method,it's supposed that IS with PSO(PSOIS)and adaptive IS(AIS)under multi-failure mode.Both of the two methods use penalty function at the same time.The most probability point problem is translated into optimization problem.The difference is the importance sampling function is established after the optimization algorithm in PSOIS.While the center of importance sampling can't stop moving,until reaching the most probability point.In numerical examples,the former PSOIS has a high efficiency,but the latter AIS has a strong adapt ability.(4)It's supposed that the involute tooth profile model and the method of locating the undercutting point.The relationship between the design parameter and the undercutting point location.The formula of undercutting point using PMOPSO method is supposed.In numerical examples,compared with the classical formula,the method in article has much more adaptability and higher accuracy.On the basis of the involute tooth profile model and undercutting point formula,involute tooth profile aided design software is developed.Software in 3D mechanical design software NX is also developed,which is used for eccentricity gear design.(5)Related to the defect of traditional relieving cam,H-type follower motion program is supposed for improving force performance at the transition point.Design model of H-type relieving cam is built.It's said that H-type motion program has a much lower shock at the transition point during the cutting process.H-type relieving cam optimization model is established.The object function is the size of H-type relieving cam.The design variables include the offset and initial movement of followers.With reference to the general criterion of cam design,the constraints include pitch profile curvature and pressure angle distribution.PMOPSO method is used for the optimization of the 3-rise and 4-rise cam.Compared with the general method and the maximum pressure angle method,PMOPSO method provides the solution with better performance.The area of optimized relieving cam decrease significantly.The abstract theory formula has been translated into software implementation.The actual test results demonstrate that this software can improve design quality and efficiency during the relieving cam design process obviously.(6)There is a comprehensive analysis of effects of geometry eccentric error and move-ment eccentric error on gear transmission error.The formulas of meshing line increment error are presented.One-stage,two-stage and power turret gear system transmission error analysis model is established one by one.Recursive algorithm used for computing system output error has been put forward.Transmission error of turret is acquired quickly using this algorithm above.The algorithm can also be used for turret optimization.GA is used for optimization of turret transmission error.Then some design points are obtained.Reliability probability analysis model of system is established.Failure probability and parameter sensitivity are evaluated using PSOIS method.The design point with high re-liability is selected among the alternative points.According to the results,the tolerance of important dimensions should be calculated again.(7)This research focuses on the switch mechanisms of some type servo power tool turret.Two degrees dynamic model of wheel type switch mechanisms is established.On the basis of this dynamic model,dynamic response of tool disk during the tools switching process for T-type and S-type motion program is presented.Furthermore,residual vibration of switch mechanism at the target position is shown.Optimization model of switch mechanism is built,whose object function is residual vibration coefficient.Design variables come from the modification coefficient of transmission gear.Contrast before and after optimization,system residual vibration is reduced obviously,especially S-type system.There is a comprehensive analysis of inertia moment,damp coefficient and stiffness coefficient in the switch mechanism dynamic model of effects on residual vibration coefficient at the target position.The design method and calculations are given out,which can provide some suggestions on promoting performance of tool turret. |
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