Robust Optimization Design Of Gearbox On High-speed EMU

In the existing research results, for the research of high-speed EMU gearbox robust optimal design is relatively few, and the gearbox is the key device of power transmission. Therefore, its research on the robustness is crucial. Under considering the influence of controllable factors and uncontrollable factors on the quality characteristics of high-speed EMU gearbox, we adopt the robust optimization design methods to establish the relevant mathematical models to solve the fluctuation of quality characteristics on influence factors. In this paper, we do analysis and research about robust optimization on the volume, assembly dimension chain and gear backlash of the high-speed EMU gearbox assembly. The main contents are as follows:(1) Considering the uncertain factors in the engineering application problems, the robust optimization method can effectively reduce the interference of uncertain factors. In the paper, the volume of high-speed EMU gearbox is defined as an objective function. The fluctuation of its constraint functions to the uncertain factors is analyzed by sensitivity analysis method, and the maximum fluctuation of sensitivity function from them to be as an additional objective function is chosen. The volume of high-speed EMU gearbox and the maximum fluctuation of constraint functions to the uncertain factors are achieved the minimum at the same time. In doing this, the fluctuation range of gearbox volume is reduced. The dual objective functions are converted into a single objective function by the physical programming method. The example shows that the robust optimization design method can make the gearbox volume to achieve the goal of robustness, and provides a theoretical basis for the development of EMU components in the future.(2) For robust optimization design of assembly dimension chain on a high-speed EMU gearbox. Because the type of gearbox is the single stage helical gear transmission device that is relatively simple one. The each component of dimension chain is in the normal distribution. We establish the fuzzy robust optimization design model on gearbox’s assembly dimension chain. But, this is a double objective model about tolerance and high grade rate, then we change the double objective function into a single objective function by using the physical programming method and the method of weighting coefficients. And we get the results of optimization by using genetic algorithm toolbox in MATLAB software, analyze and compare all the data results, then achieve the whole assembly dimension and tolerance, and in the treatment of multi-objective functions, the results achieved by using physical programming method are more robust than by using the weight coefficient method.We carry out robust optimization design for a high-speed EMU gear backlash by using Taguchi robust design. Firstly, the main influence factors of gearbox backlash are analyzed, and then sums up the factors which can be used as the design variables(controllable factors) and which can be used as noise factors(uncontrollable factors). And establish the level table of controllable factors and uncontrollable factors, then analyze the type of objective value and select the suitable orthogonal table to carry out orthogonal test. With the Taguchi robust design method on the consideration of the SNR is used to analyze the test results and obtain the best combination of decreasing gear backlash, and compared with the orthogonal experiment analysis, then analyze the advantages and disadvantages. Finally, we obtain the smaller group of the robust design parameters of gear backlash.