Abstract:The mining process of granular materials is a complex nonlinear dynamic problem, thus the optimization of bucket grab problem is difficult to achieve due to the uncertainty of dynamic equilibrium equation. This paper takes the coal mine scissor bucket grab as an example. Firstly, we establish the mathematical model of grab to obtain the mining performance data samples in different design parameters. Then, we construct threefactor and fivelevel orthogonal test to establish the quadratic polynomial response surface model of the optimization function of granular material mining performance, and solve the undetermined coefficient vectors of response surface model by the least square method. Finally, we obtain a better performance product by optimizing geometric parameters of the grab based on the ideal point method of multiobjective optimization. The results show that the proposed method has good predictive ability, and greatly reduces the scale of simulation calculation by comparing with the results of Monte Carlo method.