Research On Multidisciplinar Optimization Of Wheel Loader Working Device

Wheel loader is a kind of construction machinery which has been widely used in highway,railway, construction, water electricity, harbor, mine and other infrastructure projects. As theworking device of the wheel loader is the component which load materials directly and is relatedto the size of the wheel loader whole structure, operating efficiency, operating cost and servicelife cycle so try to design it as reasonable as possible is needed. When the working device isdesigned many factors should be considered such as the bucket cross-sectional shape, thelocations of nine hinge points on the linkage mechanism and the performance constraints whichmainly included mechanism tear, mechanism interference, mechanism translation performance,auto laying characteristic and so on. Existing study were usually focused on part of the bucketmechanism or linkage mechanism. As the working device is linked together so it is obviouslydifficult to achieve a overall optimum value when the independent structure optimal value hasbeen combined simply. In order to optimize the working device systematic the methodology ofmultidisciplinary optimization (MDO) theory has been introduced into the design of the workingdevice in this paper.The main contents are listed as follows:In first chapter firstly the situation of study and existing problems of wheel loader workingdevice optimization design have been analyzed and secondly the basic theory and main researchcontents of multidisciplinary optimization have been introduced. Finally how to use themultidisciplinary optimization methodology to design the wheel loader working device has beendiscussed.In second chapter firstly the traditional design process of the wheel loader working device isintroduced and secondly the loader working device is decomposed into two sub-disciplineswhich are mechanism sub-discipline and structure sub-discipline and then the MDO processmodel of the working device is given which can be used to guide the optimization in the thirdchapter, the forth chapter and the fifth chapter.How to carry out the mechanism sub-discipline optimization is discussed in third chapter.The mechanism sub-discipline has been divided into two parts which are bucket discipline andlinkage mechanism discipline. The bucket structure is optimized using a non-constraintoptimization algorithm which is combined with a sensitivity analysis. The linkage mechanism isoptimized using a penalty function and genetic algorithm(GA) which combined with a sensitivityanalysis also. The sensitivity analysis is useful to determine the role of different design variables that used in the work device MDO and the main design variables that influenced the optimizationvalue greatly must be taken into consideration carefully is discussed.How to carried out the structure sub-discipline optimization is discussed in the fouth chapter.The loader working device are mainly consisted of the bucket, working arm, rocker arm and soon. In this paper the working arm is analyzed and optimized thoroughly which is used the finiteelement analyzes(FEA) method based on the numerical calculation. The sensitivity of the designvariables of these structures has been analyzed which can be used in the fifth chapter.In the fifth chapter a improved concurrent sub space optimization(CCSO) method whichbased on the global sensitivity equation(GSE) has been used to coordinate and integrate theworking device mechanism sub-disciplinary optimization result and structure sub-disciplinaryoptimization result. A model wheel loader has been used as an example to validate the MDOtheory and methodology which presented in this paper. The mechanism kinematics simulationand performance analysis result which is compared with the model before optimization has beenindicated that multidisciplinary optimization can improve the main operating performance of theworking device.In the sixth chapter the summary and prospect of this paper are conducted.