Research On Modeling And Internal Model Control For Grinding Process

In mineral processing of metallurgical industry,grinding is the first process of extracting metals.The function of grinding is to crush large particles of raw ore into small particles of suitable size.Then the required metal minerals are separated from the gangue or other metal minerals for facilitating the subsequent selection.The hydrocyclone feed concentration is an important technical index in the grinding process.Its value directly affects the size of grinding grain.Therefore,this thesis takes the two stage grinding closed loop as the research object and uses the hydrocyclone feed concentration as the main control target.The mathematical model is established by the method of experiment and decoupling,and the improved fuzzy internal model control is introduced to realize the stability control of the hydrocyclone feed concentration.The main contents of this paper are as follows:Firstly,according to the grinding mechanism model and experimental data,a mathematical model of the two stage grinding process is established.The model's inputs are the supplement water of pump pool and the classifier overflow.And the spin concentration and the overflow of the cyclone as the outputs.The internal model decoupling method is used to eliminate the coupling between the inputs and outputs.The method of model reduction is used to reduce the computation of the decoupling process.Then the mathematical model between the filling water of the pump pool and the hydrocyclone feed concentration is obtained.Secondly,in order to overcome the problems of random interference,parameter variation and large delay in the two stage grinding process,the T-S fuzzy model of inhomogeneous domain is used to identify the controlled object and regarded as the internal model of the internal model control.The inverse model of T-S model is used as the internal model controller.The stability and robustness of the system are verified by theoretical deduction,and the simulation experiment is done.The simulation results show that the improved fuzzy internal model control has the characteristics of small overshoot,strong robustness and good stability compared with other methods.The stability control of the hydrocyclone feed concentration is realized.Finally,the practicality of improved fuzzy internal model control method theory is verified by the hardware in the loop simulation platform of grinding process.The virtual object system,the virtual execution system,the monitoring system and the optimization system of the simulation platform are designed.The experiment of hardware in the loop simulation platform shows that the improved fuzzy internal model control has a good control effect on the spin concentration.