Research On Improving The Optimal Design Efficiency Of The Hydraulic Excavator

Based on the comprehensive analysis of the optimal design of the complex models and the research of relative technologies in the hydraulic excavator,some methods in improving the optimal design efficiency of the hydraulic excavator are proposed in the thesis,against the problems existing in the research of the optimal design of the hydraulic excavator.The main propress of the above research is reflected as the following three aspects.1.Decomposition method of complex optimization model.Complex optimization model is usually decomposed into a number of smaller sub-models according to the principle of disciplines,problems or components,so that the optimization results could be obtained easily after decomposition.In order to reduce the impacts of coupling factors on system performance in complex optimization model,the thesis proposes a decomposition method based on the global sensitivity information.In this method,the complex optimization model is decomposed based on the principle of minimizing the sensitivity sum between the design functions and design variables among different sub-models.The design functions and design variables,which are sensitive to each other,will be assigned to the same sub-models as much as possible to reduce the impacts to other sub-models caused by the changing of coupling variables in one sub-model.The optimal design of the gear reducer is taken as an example,which is one of the standard examples that NASA assesses the performance of MDO(Multidisciplinary Design Optimization,MDO)algorithm.Two different collaborative optimization models of the gear reducer are built up separately in the software Isight,the optimized results turned out that the decomposition method proposed in this thesis has less analysis times and increases the computational efficiency by 29.6%.2.Optimal design the structural intensity of hydraulic excavator working device based on surrogate model.The optimal design of hydraulic excavator working device is often characterized by computationally expensive physically based analysis methods,such as finite element analysis(FEA),which means an excessive computational cost and long computation time have to be paid on.An effective alternative is known as the surrogate model.A new parameter setting strategy combining the dimension variable between the hinge joints and the forces loaded on the hinge joints are selected as the surrogate modeling parameter.Based on this new modeling strategy,the shape of the working device can be maintained.Simultaneously,the variation of the forces loaded on every hinge joint is fully considered as well,which can guarantee that the working device surrogate models have sufficient precision.Comparative of four different surrogate methods are presented to construct the structural intensity surrogate models of the working device,and select the one that best fits the hydraulic excavator working device,so as to avoid the time-consuming FEA in the optimal design.3.The hydraulic excavator collaborative optimization designThree optimal models,consists of the technical performance,the working efficiency of the hydraulic pump and the working device structural intensity are taken into consideration in the optimal design of the hydraulic excavator.The efficiency of the hydraulic pump should be increased as much as possible in the main mining area,so as to reduce the fuel consumption of the hydraulic excavator.Based the decomoposition strategy proposed in the thesis,the 80T and 20T hydraulic excavators are taken as examples,the collaborative optimization is carried out after the hydraulic excavator model is decomposed into several sub-models,in order to improve the optimal design efficiency of the hydraulic excavator.Some experiment testings are conducted to verify the correntness of the optimal results.