| The mine hoisting system is one of the most important mineral production and transportation equipment whose hydraulic braking system is the guarantee for improving the safety and controlling normal operation of the system.Especially in the event of a sudden accident,the safe braking of the hydraulic system is the last and only means to protect the safety of the lifting system.The higher mine equipment automation technology and energy demand are getting,the more attention coal mine safety has received correspondingly.The 2016 version of the Coal Mine Safety Regulations and the 2017 edition of the mechanical industry standard JB/T 3277 Miner Hoist and Mining Hoist Hydraulic Station have made higher demands on the performance of hydraulic braking systems.Experts,scholars and organizations in the industry have started research on hydraulic braking systems.The constant deceleration and safe braking as the main function of the hydraulic braking system and the immature technology in China have caused the research hotspot.In view of the shortcomings of switching between constant deceleration braking failure protection and standby safety braking in the classic hydraulic station,this paper adopts a hydraulic station scheme based on proportional directional valve and accumulator for constant deceleration braking control.The hydraulic station has two independent constant deceleration brake channel,which can automatically switch to the standby channel after the active channel fails to continue constant deceleration braking,and the failure of the active channel will not affect the working performance of the standby channel.According to the dual-channel constant deceleration braking hydraulic station designed in this paper,an electronic control device using PLC+MCU two-stage control is proposed.The PLC,responsible for the overall logic control(PM573 for CPU),brake control card(CPU STM32F405RG)that control constant deceleration of the braking process and sensor device were designed or selected.The software system of the electronic control device was designed.In order to solve the problem of difficulty in modeling the constant deceleration braking process,a system identification method is introduced to model the constant deceleration braking process.Through the simplification and analysis,the model structure of the constant deceleration braking process is obtained.The field data are designed for experiments.The model parameters are identified based on the recursive least squares algorithm.For the problem of the traditional PID control is not ideal in the constant deceleration braking process,a double closed-loop control scheme of PID pressure regulation and DMC deceleration adjustment is proposed.According to the model identified in this paper,the parameters of PID controller and DMC controller are set.Finally,using the simulation environment of MATLAB+ Simulink,the design control method is verified on the basis of the mathematical model. |
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