Study On Sliding Mode Control Of Mine Filling Slurry Concentration Based On Preview Theory

With the substantial increase of mining in recent years,the ground collapse and environmental problems caused by mining have been increasingly exposed,which have become very serious environmental and social problems.It is urgent to solve these problems,so experts put forward the method of mine filling.The mine filling system uses the tailings produced by mining to fill the goaf,maximizes the use of mineral resources,greatly reduces the generation of solid waste,and solves the problems of environmental pollution,waste of resources and hidden dangers of safety from the source.As an important step in mining,the important factors affecting the filling quality are the composition of the filling slurry,the control of the slurry concentration and the filling technology.In this paper,taking the filling slurry production process as the research object,the filling slurry concentration control has the characteristics of large lag,and the sliding mode preview controller,integral sliding mode preview controller and double-power sliding mode preview controller are designed.The response speed and robustness of the system are deeply studied.The main research contents are as follows:(1)First of all,the technological process of the mine filling system is introduced,and the production process of the filling slurry is determined as the research object of this study.According to the mechanical characteristics of the slurry preparation equipment,the mathematical model of the slurry concentration system is established.Then the mathematical model is transformed from the form of polynomial to the state space form of observable standard form.Finally,in order to facilitate the design of the controller,the mathematical model with time delay is transformed into the form without time delay by a method of variable substitution,and the tracking control problem of the original system is transformed into the optimal tracking control problem of the equivalent system without time delay.(2)Aiming at the problem of concentration control of mine filling slurry,a sliding mode preview control algorithm with feedforward compensation function is proposed.This method not only has the advantage that the preview controller uses the future information of the target signal to improve the tracking characteristics of the servo system,but also has the advantage that the sliding mode controller has strong robustness to parameter changes and disturbances.Firstly,the augmented error system is constructed by using the known information of the slurry concentration control system in the future,and then a sliding mode preview controller is designed on the basis of the augmented error system.Finally,the designed controller is substituted into the slurry concentration control system to verify its rationality and effectiveness,and the simulation results are compared with the optimal preview controller to prove the superiority of the algorithm.The simulation results show that the sliding mode preview control algorithm has better control performance,but the deficiency of this algorithm is that the "chattering" phenomenon exists in the control law of the controller,and the "chattering" phenomenon will cause the controller to switch frequently.In the actual system,the electric valve of the water tank can’t open and close frequently,so the phenomenon of "chattering" should be avoided when designing the controller.(3)In view of the concentration control of mine filling slurry and the existence of "chattering" phenomenon in sliding mode preview control,an integral sliding mode preview controller is proposed.Firstly,the integral sliding mode surface is designed to make the sliding mode of the system stable by switching exponentially.Then an integral sliding mode foresight controller is designed to make the system on the sliding mode surface in the initial state.Finally,the designed controller is substituted into the slurry concentration control system to verify its rationality and effectiveness,and the simulation results are compared with the sliding mode preview controller to prove the superiority of the algorithm.The simulation results show that the integral sliding mode preview controller can effectively restrain the chattering phenomenon.In order to solve the problem that the integral sliding mode preview controller is insensitive to the parameter perturbation and external disturbance of the system,and the chattering may occur under the action of parameter perturbation and external disturbance,the extended state observer(ESO)is added on the basis of the integral sliding mode preview controller to improve the insensitivity of the integral sliding mode preview controller to the parameter perturbation and external disturbance of the system.At the same time,the chattering problem of the controller is solved.It is substituted into the slurry concentration control system for simulation verification.The simulation results show that after adding the extended state observer,the anti-interference ability of the system is obviously improved,and the chattering phenomenon of the system is suppressed at the same time.The stability and rapidity of the system are improved.(4)In view of the slow convergence speed and "chattering" shortcomings of the traditional reaching law,a sliding mode preview control strategy based on double power reaching law is proposed.The double-power sliding mode preview control algorithm has the characteristics of global fast and fixed time convergence.The designed controller is substituted into the slurry concentration control system to verify its rationality and validity,and the simulation results are compared with the power sliding mode preview controller and the sliding mode preview controller to prove the superiority of the algorithm.The simulation results show that the double-power sliding mode preview controller can improve the convergence speed of the system,restrain the chattering phenomenon and enhance the robustness and rapidity of the system.