Parameters optimization of dragline working platform based on nonlinear programming

To improve the production efficiency of dragline and reduce the production costs of dragline operation,the parameters of dragline working platform should be optimized. However,due to the interaction of the weights and heights of dragline working platform,individual parameters cannot be optimized independently. Thus,the optimization model taking them as variables should be established,and the comprehensive optimization method for the parameters of drag- line working platform should be proposed. Therefore,the dragline digging ranges in the situations of one-way and round trip operation were analyzed. The calculating formulas of digging depth under varying conditions,and forward and re- verse walking distance were deduced,the calculation methods of dragline walking time and working cycle were presen- ted,and the relationships between the heights of dragline working platform,its weights and dragline production efficien- cy were built. In addition,the curve equation of muck pile profile was fitted on the planar cartesian coordinate system based on the three-dimensional laser scanning data of casting blast muck pile,and thus the computation methods of the effective throw rate,duplicate stripping rate of dragline,auxiliary stripping rate,dragline stripping rate were proposed. By taking the minimum stripping cost of dragline stripping system as objective function,the model for optimizing drag- line working platform parameters based on non-linear programming was established in comprehensive consideration of the technical,economic and security factors. The constraint conditions of working bench parameters were analyzed com- prehensively,including the safety constraints affecting dragline operation and safety of high bench stability,the dragline line specifications constraints concerning the dragline stripping distance and digging depth,and the production capacity limit of dragline and auxiliary equipment. Finally,the solving method of the model was put forward. The study of Heid- aigou surface coal mine shows that the production efficiency of dragline increases at first and then decreases with the increase of weights and heights of dragline working platform. When the working platform height is 13. 30 m,and work- ing bench weight is 118. 10 m,the production efficiency of dragline is the biggest,which is 4 043. 02 m3 / h. The opti- mum working bench weight and height are 118. 00 m,and 14. 60 m respectively,which will save the production costs of dragline stripping system at 3. 717 0 million Chinese yuan a year.