Model predictive control pressure-stabilizing liquid supply method for hydraulic support liquid supply system

Abstract

The invention provides a hydraulic support liquid supply system model prediction control pressure-stabilizing liquid supply method, and belongs to the technical field of intelligent control of fully mechanized coal mining face liquid supply systems. Liquid supply system parameters are obtained by constructing a hydraulic support liquid supply system model, and meanwhile the distance between a current execution action hydraulic support set and an emulsion pump station is judged through the electromagnetic switch state of each execution mechanism reversing valve of a hydraulic support; liquid supply system parameters and the distance between the hydraulic support set executing the action currently and the emulsion pump station are input into the long-distance liquid supply pipeline model, and the pressure loss and the pipeline pressure transmission time at the position where the hydraulic support executes the action currently are obtained; the flow solver is used for obtaining the flow value meeting the control target of the outlet pressure of the emulsion pump station and the advanced liquid supply time and the advanced adjustment flow value under the current action of the hydraulic support when the hydraulic support executes the next action. The method is simple in step and convenient to use, and the liquid supply end of the emulsion pump station can be quickly and accurately matched with the liquid needing end of the executing mechanism.

Description

Technical Field

[0001] The invention belongs to the technical field of pressure control of a fluid supply system of a fully mechanized mining working face, and in particular relates to a method for pressure-stabilized fluid supply of a hydraulic support fluid supply system under model prediction control. Background Art

[0002] With the development of hydraulic supports in fully mechanized mining faces with large mining heights, higher requirements have been placed on the output capacity of underground fluid supply systems, and long-distance transmission stabilization and flow control technology has become a key technology that urgently needs to be broken through. The hydraulic support fluid supply system for fully mechanized mining faces has the characteristics of high pressure, large flow, and long pipelines. In order to meet the requirements of quickly following the coal mining machine, the hydraulic supports work quickly in groups, and many actuators act frequently in time-sharing. In addition, the frequent changes in the load on the coal mining face have led to strong time-varying pressure fluctuations in the fluid supply system, poor pressure stabilization, and difficult to guarantee the production efficiency and equipment reliability of the fully mechanized mining face.

[0003] The hydraulic support has the characteristics of working in groups in different time periods. Its main actions include: pushing and conveying, lowering, moving, raising and protecting. As the hydraulic support on the working surface continues to move, the liquid supply distance on the working surface also changes with the position of the hydraulic support that performs the action. It has a certain weak periodicity. Therefore, the pressure and flow rate during the action process have certain periodic evolution characteristics. In view of this feature, most of the existing predictions are based on the support action category and perform simple static flow demand analysis. It does not interact with the characteristics of the liquid supply system and pipelines, making it difficult to dynamically determine the flow control target of the liquid supply system in real time.

[0004] Therefore, a pressure stabilization control strategy is proposed: a model predictive control pressure stabilization method for the hydraulic support fluid supply system of the coal mining working face based on the pressure prediction of the fluid supply system model + parallel pump control / flow valve control flow regulation method, so as to accurately and quickly supply fluid to the working face, ensure that the fluid supply flow can meet the action requirements in time, improve the response speed of the fluid supply system, reduce the pressure shock of the fluid supply system, and improve the pressure stabilization effect of the working face. Summary of the invention

[0005] In view of the shortcomings of the existing technology, a model predictive control and pressure stabilizing fluid supply method for a hydraulic support fluid supply system is provided. The influence of long-distance fluid supply on the power transmission characteristics of the system is taken into consideration, the power evolution characteristics of the entire system are analyzed, and the pressure response relationship and pressure lag time caused by the long-distance fluid supply pipeline are accurately obtained. Furthermore, the real-time advanced fluid supply matching relationship between the fluid supply end flow rate and the actuator required fluid end flow rate is obtained, which effectively improves the matching speed and accuracy between the fluid supply flow rate of the hydraulic support fluid supply system and the required fluid volume of the hydraulic support emulsion cylinder end, reduces the pressure shock of the system, and improves the pressure stabilizing effect of the fluid supply system.

[0006] In order to achieve the above technical objectives, a method for pressure-stabilized liquid supply by model prediction control of a hydraulic support liquid supply system of the present invention comprises the following steps:

[0007] The number of all hydraulic supports in the entire hydraulic support fluid supply system, the cylinder diameter of each actuator of the hydraulic support, the rod diameter of each actuator of the hydraulic support, and the design speed are obtained as basic parameters;

[0008] A hydraulic support fluid supply system model is constructed according to the hydraulic support fluid supply system. The hydraulic support fluid supply system model includes a large inertia emulsion pump model, an accumulator model and an unloading valve model for digitally simulating an emulsion pump station, a long-distance fluid supply pipeline model for digitally simulating a long-distance fluid supply pipeline, a hydraulic support electromagnetic reversing valve group model and a hydraulic support emulsion cylinder model for digitally simulating a hydraulic support; wherein the large inertia emulsion pump model is connected to the long-distance fluid supply pipeline model through the accumulator model and the unloading valve model, and the long-distance fluid supply pipeline model is respectively connected to the hydraulic support electromagnetic reversing valve group model and the hydraulic support emulsion cylinder model; the hydraulic support fluid supply system model can derive the execution action information of the current hydraulic support by reading the electromagnetic reversing valve switch signals on all hydraulic supports in the hydraulic support fluid supply system;

[0009] Construct a flow solver to calculate the flow value that meets the outlet pressure control target of the hydraulic supply system and the lead time of the hydraulic support action;

[0010] The distance between the hydraulic support currently executing the action and the emulsion pump station is calculated to obtain the distance x between the current hydraulic support and the emulsion pump station. i ; The current hydraulic support load force F is obtained by the hydraulic support load force estimation method i According to the basic parameters of the hydraulic support fluid supply system, the distance x between the current hydraulic support and the emulsion pump station, and the current hydraulic support load F i Input the hydraulic support fluid supply system model, so that the hydraulic support fluid supply system model outputs the system parameter information corresponding to the hydraulic support action state: emulsion pump station outlet pressure / pipeline inlet pressure, hydraulic support end pressure / pipeline outlet pressure, emulsion pump station fluid supply state / unloading valve state, hydraulic support end fluid use state / hydraulic support electromagnetic reversing valve switch signal;

[0011] The output of the hydraulic support fluid supply system model is input into the long-distance fluid supply pipeline model to obtain the pipeline pressure p at any position x from the emulsion pump station in the current action state. x =f(x, p0); Pipeline pressure transmission time Δt at any position x from the emulsion pump station = x / v x , v x =f(x,v);v x is the average flow velocity of the fluid in the pipeline, and v is the outlet flow velocity of the emulsion pump station;

[0012] Substitute the current distance x between the hydraulic support and the emulsion pump station into p x =f(x, p0) and Δt=x / v x , v x =f(x, v), and the pressure loss Δp at the current hydraulic support execution point is obtained x The pipeline pressure transmission time Δt at the current hydraulic support execution point x ;

[0013] The pressure loss Δp at the current hydraulic support execution point x , the pipeline pressure transmission time Δt at the current hydraulic support execution point x , the outlet pressure of the emulsion pump station, and the basic parameters of the current hydraulic support are input into the flow solver to predict the flow value that meets the outlet pressure control target of the liquid supply system in the next time period and the advance liquid supply time Δt under the current hydraulic support action. a ;

[0014] The predicted flow value and the advance liquid supply time Δt a The flow regulating actuator is input to obtain the parallel pump control / flow valve bypass advance regulating flow value, and the parallel pump control / flow valve bypass advance regulating flow value is used to advance regulate the flow.

[0015] The specific steps are as follows:

[0016] A working cycle of the hydraulic support in the working surface includes pushing the conveyor, lowering the frame, moving the frame and raising the frame. Therefore, the flow and pressure of the hydraulic support fluid supply system in the working process of the hydraulic support have weak periodic characteristics. A hydraulic support fluid supply system parameter database for the hydraulic support action process is established to record the outlet pressure of the emulsion pump station, the pressure at the emulsion cylinder end of the hydraulic support, the fluid supply status of the emulsion pump station and the fluid status data of the emulsion cylinder end of the hydraulic support during each working cycle of the hydraulic support in the working surface;

[0017] The switch signal of the electromagnetic reversing valve of the hydraulic support is used to judge the execution action of the hydraulic support.

[0018] When it is detected that the current execution action of the hydraulic support is inconsistent with the action type recorded in the parameter database of the hydraulic support fluid supply system, the current action hydraulic support execution action is obtained according to the switch signal of the electromagnetic reversing valve of the current hydraulic support, and the basic parameters of the hydraulic support fluid supply system are obtained; the distance x between the current hydraulic support and the emulsion pump station is calculated; and the current hydraulic support load force F is estimated. i ;

[0019] The basic parameters of the hydraulic support fluid supply system and the distance x between the hydraulic support and the emulsion pump station i , hydraulic support load Fi Input the hydraulic support fluid supply system model, and output the outlet pressure of the emulsion pump station, the pressure at the end of the hydraulic support, the fluid supply status of the emulsion pump station, and the switch signal of the electromagnetic reversing valve of the hydraulic support after simulation of the hydraulic support fluid supply system model;

[0020] Using the long-distance liquid supply pipeline model, according to the distance x between the hydraulic support and the emulsion pump station, the current hydraulic support load F i , calculate the pressure p in the pipeline at any position x away from the emulsion pump station x =f(x, p0); Pipeline pressure transmission time Δt at any position x from the emulsion pump station x =x / v x , v x =f(x,v);

[0021] Input the distance x between the current hydraulic support and the emulsion pump station to obtain the pressure loss Δp at the current hydraulic support execution point. x The pipeline pressure transmission time Δt at the current hydraulic support execution point x ;

[0022] The pressure loss Δp at the current hydraulic support execution point x , the pipeline pressure transmission time Δt at the current hydraulic support execution point x , the outlet pressure of the emulsion pump station, and the basic parameters of the hydraulic support in the current action are input into the flow solver to obtain the flow value that meets the control target of the outlet pressure of the emulsion pump station and the advance liquid supply time Δt under the current hydraulic support action when the hydraulic support performs the next action a ;

[0023] The flow value that satisfies the hydraulic support to perform the next action and the advance fluid supply time under the current hydraulic support action, i.e., Δt a Input flow regulating actuator, through which the parallel pump control / flow valve bypass is controlled to perform flow regulation in advance;

[0024] When it is detected that the current execution action of the hydraulic support is consistent with the action type recorded in the hydraulic support fluid supply system parameter database, the corresponding emulsion pump station outlet pressure, hydraulic support end pressure, emulsion pump station fluid supply status, and hydraulic support end fluid status data are called according to the hydraulic support electromagnetic reversing valve switch signal;

[0025] According to the current distance calculation method between the hydraulic support and the emulsion pump station, the current distance x between the hydraulic support and the emulsion pump station is obtained; according to the current hydraulic support load force estimation method, the current hydraulic support load force F in the long-distance liquid supply pipeline model input is obtained i ;

[0026] The current state of x and Fi Input the long-distance liquid supply pipeline model to obtain the pipeline pressure p at any position x from the emulsion pump station under the current operating state. x =f(x, p0); Pipeline pressure transmission time Δt at any position x from the emulsion pump station x =x / v x , v x =f(x, v); get the pipeline pressure transmission time Δt corresponding to the distance x between the current hydraulic support and the emulsion pump station i The pressure loss Δp at the current hydraulic support execution point is brought into the flow solver to update the output;

[0027] According to the flow solver update in the future to meet the outlet pressure control target of the fluid supply system flow value and the advance fluid supply time Δt under the current hydraulic support action a , input flow control actuator, and control the parallel pump control / flow valve bypass through the flow control actuator to adjust the flow in advance.

[0028] Furthermore, the working process of the flow regulating actuator is specifically as follows: replenishing the liquid in parallel through the replenishing pump to quickly increase the maximum liquid supply flow of the emulsion pumping station, and reducing the liquid supply flow of the emulsion pumping station through bypass throttling of the flow valve, and performing flow regulation in advance according to the flow value obtained by the flow solver and the pressure transmission time of the long-distance liquid supply pipeline: by increasing or reducing the output flow of the emulsion pumping station in advance, the lag caused by the pressure transmission is compensated.

[0029] Furthermore, the input signal value of the long-distance liquid supply pipeline model has the characteristic of being adjusted according to the switch signal of the electromagnetic reversing valve of the hydraulic support; according to the electromagnetic reversing valve signal of the hydraulic support, the long-distance liquid supply pipeline model is used to calculate the distance between the current hydraulic support and the emulsion pump station. The specific calculation method is as follows:

[0030] Assume that the hydraulic support currently in action is numbered m in the hydraulic support group, and the distance between the current hydraulic support and the emulsion pump station is x. m = Length of chute pipeline + (m-1) * spacing between racks.

[0031] Furthermore, the current hydraulic support load force estimation method is as follows: according to the action type of the current hydraulic support, when the load force F is firstly calculated for a certain action in the periodic action of the hydraulic support, i When estimating, analyze the stress conditions and characteristics of the corresponding action process of the hydraulic support, analyze the friction resistance between the hydraulic support and the working face roof, coal wall, and ground according to the current hydraulic support action type, and calculate the current hydraulic support load force F according to the stress analysis. i To estimate, when it is not the first time to perform a load force F on an execution action iWhen estimating, the Coulomb pressure model is used to calculate the load on the support. At this time, F i =C*P avg *A, where C is the empirical coefficient, P avg is the average outlet pressure of the emulsion pump station, and A is the effective area of ​​the emulsion cylinder on the hydraulic support.

[0032] Furthermore, the hydraulic support fluid supply system model predictive control and pressure stabilization fluid supply method has the characteristics of parameter updating; the model update cycle is divided according to the different action times of the hydraulic support, and the total time for the hydraulic support to perform one push-conveyance, frame lowering, frame moving and frame lifting action is taken as the model update cycle, and the actual measured pressure of the fluid supply system during each cycle action is recorded; when the model is updated, the predicted outlet pressure of the hydraulic support emulsion pump station is obtained according to the switching signal of the hydraulic support electromagnetic reversing valve, and compared with the corresponding pressure segment in the measured periodic pressure data of the hydraulic support fluid supply system of the comprehensive mining working face, and according to the pressure difference, the hydraulic support fluid supply system model and the mean pressure change rate parameter in the flow solver are adjusted and optimized to improve the accuracy of the hydraulic support fluid supply system model for pressure prediction.

[0033] Furthermore, the flow of emulsion in the pipeline in the entire hydraulic support fluid supply system model needs to consider the friction term correction, and the dynamic evolution conforms to the high-pressure, large-flow turbulent unsteady flow pipeline equation corrected by the Brunone additional friction model, which is expressed as follows:

[0034]

[0035] Wherein, g is the acceleration of gravity, H is the relative height difference of the pipeline, v is the flow velocity of the fluid in the pipeline, a is the pressure wave velocity, k3 is the Brunone friction coefficient, f is the friction coefficient in the pipeline, θ is the angle between the pipeline and the horizontal line, and D is the diameter of the pipeline;

[0036] The influence of the turbulent state in the pipeline and the strong time-varying load on the characteristics of the long pipeline is considered through the high-pressure, large-flow turbulent unsteady flow pipeline equation, and the friction term of the emulsion in the pipeline is corrected.

[0037] Furthermore, the long-distance liquid supply pipeline model is used to solve the pressure at any point in the pipeline:

[0038] The pressure in the pipeline at any position x from the emulsion pump station in the entire working surface: p x =f(x, p0), where x is the distance from a point on the pipeline to the emulsion pump station, and p0 is the outlet pressure of the emulsion pump station;

[0039] The pressure loss Δp at any position x in the entire working face from the emulsion pump station x =p0-p x ;

[0040] The pipeline pressure transmission time at any position x from the emulsion pump station in the entire working surface is:

[0041] Δt x =x / v x , v x =f(x,v),

[0042] Where x is the distance from a point on the pipeline to the emulsion pump station, v x is the average flow velocity of the fluid in the pipeline, and v is the outlet flow velocity of the emulsion pump station;

[0043] The pipeline pressure transmission time Δt at any position x from the emulsion pump station in the entire working face x =x / v x , and Δp x , Δt x As input to the flow solver model.

[0044] Furthermore, the flow required for the hydraulic support actuator to operate includes three parts: the flow of the accumulator during the entire hydraulic support operation process. The accumulator is a component in the emulsion pump station. It can adjust its output flow according to the pressure of the hydraulic support fluid supply system and play a role in absorbing the impact in the hydraulic support fluid supply system; the flow provided by the emulsion compression during the entire hydraulic support operation process; the flow generated by the emulsion cylinder action and load influence during the entire hydraulic support operation process. This part is the flow required for the smooth movement of the actuator;

[0045] The flow calculation method using the flow solver to solve the flow generated by the accumulator during the execution of the hydraulic support is:

[0046]

[0047] Among them, P u is the unloading pressure of the unloading valve, P d is the unloading valve recovery pressure, P0 is the accumulator initial pressure, V0 is the accumulator initial volume, Paˊ is ​​the rate of change of the pressure curve in the accumulator supply stage, ΔV g This is the volume change of the pipeline during this process, and βe is the elastic bulk modulus of the emulsion;

[0048] The calculation formula for the flow rate caused by the emulsion compression is:

[0049]

[0050] Among them, P inis the outlet pressure of the emulsion pump station, Δp is the dynamic pressure loss from the outlet of the emulsion pump station to the emulsion cylinder end of the hydraulic support, V is the pipeline volume from the outlet of the emulsion pump station to the emulsion cylinder end of the hydraulic support, and βe is the elastic bulk modulus of the emulsion;

[0051] The calculation formula for the flow rate generated by the emulsion cylinder action and load influence is:

[0052]

[0053] Among them, A A A is the side area of ​​the hydraulic cylinder inlet, B is the liquid return side area of ​​the hydraulic cylinder, P A is the pressure on the hydraulic cylinder inlet side, P B is the pressure on the return side of the hydraulic cylinder, m is the equivalent mass of the actuator, and F is the load force;

[0054] The flow solver outputs the flow value q required for the hydraulic support actuator to move, which is the sum of the above three flow rates. The flow solver output flow calculation formula is:

[0055] q=q x +q c +q d .

[0056] Beneficial effect: Based on the multi-pump configuration, this method establishes a hydraulic support fluid supply system model, and calculates the dynamic pressure loss Δp in real time through the long-distance fluid supply pipeline model. x The pipeline pressure transmission time Δt under the current execution action x And compensate, and the hydraulic support fluid supply system model and flow solver have parameter update characteristics, which can continuously improve the accuracy of the hydraulic support fluid supply system model output, improve the matching speed and accuracy between the hydraulic support fluid supply system fluid supply flow and the hydraulic support emulsion cylinder end fluid required, reduce the system pressure shock, and improve the pressure stabilization effect of the fluid supply system. In addition, by establishing a hydraulic support fluid supply system parameter database, according to the hydraulic support electromagnetic reversing valve switch signal, the current hydraulic support required fluid replenishment flow rate is predicted in advance to reduce the delay time of the hydraulic support fluid supply system and improve the response characteristics of the hydraulic support fluid supply system. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Figure 1 It is a schematic diagram of a hydraulic support fluid supply system model of the present invention;

[0058] Figure 2 Flow chart of the method for predicting and controlling the steady-pressure liquid supply in an embodiment of the present invention;

[0059] Figure 3 This is a schematic diagram of a long-distance liquid supply pipeline model according to an embodiment of the present invention;

[0060] Figure 4 Schematic diagram of the model parameter update process of the hydraulic support fluid supply system according to an embodiment of the present invention. DETAILED DESCRIPTION

[0061] The embodiments of the present invention are further described below in conjunction with the accompanying drawings:

[0062] like Figure 1 As shown, the present invention discloses a hydraulic support fluid supply system model, including a hydraulic support fluid supply system model, a flow solver, and a flow regulating actuator. The hydraulic support fluid supply system model includes an emulsion pump station model, a long-distance fluid supply pipeline model, a hydraulic support reversing valve group model, and a hydraulic support emulsion cylinder model; wherein the emulsion pump station model includes a large-inertia emulsion pump model, an accumulator model, and an unloading valve model, wherein the large-inertia emulsion pump model can be divided into No. 1, No. 2... pump d theoretical output flow according to the number of actual emulsion pumps, and the output flow of the emulsion pump station is simulated by the liquid conductivity coefficient. The influence of the outlet pressure of the emulsion pump station; the accumulator model is affected by the actual The flow rate of the accumulator under the filling and discharging states is simulated; the unloading valve model determines the opening and closing of the unloading valve main valve through the switching state of the pilot valve according to the structure of the actual unloading valve, thereby determining whether the outlet flow of the emulsion pump station is input into the working surface or flows back to the oil tank from the unloading valve; the hydraulic support electromagnetic reversing valve group model simulates the flow rate corresponding to the switching state of multiple groups of hydraulic support electromagnetic reversing valves according to the actual hydraulic support electromagnetic reversing valve; the hydraulic support actuator model establishes the flow continuity equation and force balance equation of the hydraulic support emulsion cylinder according to the characteristics of the actual hydraulic support actuator hydraulic cylinder to simulate the motion state of the hydraulic support emulsion cylinder.

[0063] like Figure 4 As shown in the figure, the hydraulic support fluid supply system model has the following characteristics: The hydraulic support fluid supply system model takes the switch signal of the hydraulic support electromagnetic reversing valve as the input signal, and obtains the current distance x between the actuator and the emulsion pump station through the distance calculation method between the actuator and the emulsion pump station. i ; The current hydraulic support load force F is obtained through the current hydraulic support load force estimation method i ; Through the execution of the action of the hydraulic support, the parameters such as the number of actuators of the hydraulic support fluid supply system, the cylinder diameter of the actuator, the rod diameter, etc. are obtained, so as to determine the hydraulic support fluid supply system model under the current execution state; and the outlet pressure of the emulsion pump station (pipeline outlet pressure), the pressure at the end of the hydraulic support (pipeline inlet pressure), the fluid supply status of the emulsion pump station (unloading valve switch signal), and the fluid usage status at the end of the hydraulic support (hydraulic support electromagnetic reversing valve switch signal) are output as the input of the long pipeline fluid supply model.

[0064] The current distance x between the actuator and the emulsion pump station iAccording to the estimation method, the distance between the current actuator and the emulsion pump station is estimated as follows: the hydraulic support group of the comprehensive mining working face contains n hydraulic supports, usually n can reach dozens to hundreds of units, and the frame spacing between each hydraulic support is determined. The distance between any hydraulic support of the working face and the emulsion pump station can be determined by the length of the downstream pipeline + (n-1) * frame spacing. According to the switch signal of the electromagnetic reversing valve of the hydraulic support, the number of the hydraulic support currently in action in the hydraulic support group is determined, thereby determining the distance between the current actuator and the emulsion pump station in the long-distance liquid supply pipeline model input. Assuming that the hydraulic support currently in action is numbered m in the hydraulic support group, the distance between the current actuator and the emulsion pump station x m = length of chute pipeline + (m-1) * spacing between racks.

[0065] The current hydraulic support load force estimation method is as follows: According to the current hydraulic support action type, when the load force F is first applied to a certain action during the hydraulic support cycle, i When estimating, analyze the stress conditions and characteristics of the corresponding action process of the hydraulic support, analyze the friction resistance between the hydraulic support and the working face roof, coal wall, and ground according to the current hydraulic support action type, and calculate the current hydraulic support load force F according to the stress analysis. i To estimate, when it is not the first time to perform a load force F on an execution action i When estimating, the Coulomb pressure model is used to calculate the load on the support. At this time, F i =C*P avg *A, where C is the empirical coefficient, P avg is the average outlet pressure of the emulsion pump station, and A is the effective area of ​​the actuator.

[0066] The long-distance liquid supply pipeline model has the following characteristics: The long-distance liquid supply pipeline model takes into account the influence of the turbulent state and strong time-varying load in the pipeline on the characteristics of the long pipeline, and corrects the friction term according to the working conditions. It can grasp the dynamic change law of the pressure of the bracket liquid supply system with long pipelines, high pressure and large flow, and strong time-varying load characteristics. It includes the high-pressure and large-flow turbulent non-steady flow pipeline equation corrected by the Brunone additional friction model:

[0067]

[0068] Among them, g is the acceleration of gravity, H is the relative height difference of the pipeline, v is the flow velocity of the fluid in the pipeline, a is the pressure wave velocity, k3 is the Brunone friction coefficient, f is the friction coefficient in the pipeline, θ is the angle between the pipeline and the horizontal line, and D is the diameter of the pipeline.

[0069] The long-distance liquid supply pipeline model has the following characteristics: the long-distance liquid supply pipeline model can calculate the pressure at any point in the pipeline. Figure 3 As shown, the equations are transformed by finite difference and the current hydraulic support load F i , the outlet pressure of the emulsion pump station (pipeline inlet pressure), the pressure at the hydraulic support end (pipeline outlet pressure), the liquid supply status of the emulsion pump station (unloading valve switch signal) and the liquid use status of the hydraulic support end (hydraulic support electromagnetic reversing valve switch signal) are input; the output is the pipeline pressure p at any position x of the entire working surface from the emulsion pump station x =f(x, p0), where x is the distance from a point on the pipeline to the emulsion pump station, and p0 is the outlet pressure of the emulsion pump station. The pressure loss Δp at any position x of the entire working surface from the emulsion pump station can be obtained. x =p0-p x ; Output the pipeline pressure transmission time Δt of the entire working surface at any position x from the emulsion pump station x =x / v x , v x =f(x, v), where x is the distance from a point on the pipeline to the emulsion pump station, and v is x is the average flow velocity of the fluid in the pipeline, v is the outlet flow velocity of the emulsion pump station, and the pipeline pressure transmission time Δt at any position x of the entire working surface from the emulsion pump station can be obtained. x =x / v x , and Δp x , Δt x As input to the flow solver model, Figure 3 shown.

[0070] The flow solver has the following features:

[0071] The calculation formula for the accumulator flow rate during the pump station liquid supply stage is:

[0072]

[0073] Among them, P u is the unloading pressure of the unloading valve, P d is the unloading valve recovery pressure, P0 is the accumulator initial pressure, V0 is the accumulator initial volume, Paˊ is ​​the rate of change of the pressure curve in the accumulator supply stage, ΔV g For this process, the pipe volume changes, β e is the bulk modulus of the emulsion;

[0074] The calculation formula for the flow rate caused by the emulsion compression is:

[0075]

[0076] Among them, P inis the outlet pressure of the emulsion pump station, Δp is the dynamic pressure loss from the outlet of the emulsion pump station to the emulsion cylinder end of the hydraulic support, V is the pipeline volume from the outlet of the emulsion pump station to the emulsion cylinder end of the hydraulic support, β e is the bulk modulus of the emulsion;

[0077] The calculation formula for the flow rate generated by the actuator action and load effect is:

[0078]

[0079] Among them, A A A is the side area of ​​the hydraulic cylinder inlet, B is the liquid return side area of ​​the hydraulic cylinder, P A is the pressure on the hydraulic cylinder inlet side, P B is the pressure on the return side of the hydraulic cylinder, M is the equivalent mass of the actuator, and F is the load force.

[0080] Finally, the flow solver outputs the flow value as the sum of the three parts, and the flow solver output flow calculation formula is:

[0081] q=q x +q c +q d

[0082] The flow solver has the following characteristics: The pressure loss Δp at the hydraulic support execution point where the current actuator is in action is calculated. x , the pipeline pressure transmission time Δt at the current actuator action x The basic parameters such as the outlet pressure of the emulsion pump station, the number of current actuators, cylinder diameter, rod diameter, etc. are used as input; the flow value that meets the outlet pressure control target of the liquid supply system in the future and the advance liquid supply time (Δt x ) is output and input into the flow regulating actuator.

[0083] The flow regulating actuator is used to control the flow value of the outlet pressure of the liquid supply system in the future and the advance liquid supply time (i.e. Δt x ) is input, and the parallel pump control / flow valve bypass advance adjustment flow value is output.

[0084] like Figure 2 and Figure 3 As shown, the present invention discloses a method for pressure-stabilized liquid supply of a hydraulic support liquid supply system by model prediction control, comprising the following steps:

[0085] The hydraulic support pushes the conveyor, lowers the frame, moves the frame and raises the frame as a working cycle. Therefore, the flow and pressure of the hydraulic support system have weak periodic characteristics during the working process. Therefore, a system parameter database for the hydraulic support execution process is established to record the outlet pressure of the liquid supply system pump station, the pressure at the hydraulic support end, the liquid supply status of the emulsion pump station and the liquid status data at the hydraulic support end for each working cycle.

[0086] Determine the current hydraulic support execution action according to the switch signal of the electromagnetic reversing valve of the hydraulic support. When it is detected that the execution action of the hydraulic support is inconsistent with the type in the database, obtain the current action hydraulic support execution action according to the switch signal of the electromagnetic reversing valve of the hydraulic support, and obtain the basic parameters of the hydraulic support fluid supply system; calculate the distance x between the current actuator and the emulsion pump station; estimate the current hydraulic support load force F i ;

[0087] Determine the hydraulic support fluid supply system model under the corresponding actuator action state, so as to output the outlet pressure of the emulsion pump station (pipeline inlet pressure), the pressure at the hydraulic support end (pipeline outlet pressure), the emulsion pump station fluid supply state (unloading valve switch signal), and the hydraulic support end fluid use state (hydraulic support electromagnetic reversing valve switch signal);

[0088] The above-derived parameters are input into the long-distance liquid supply pipeline model to obtain the pipeline pressure p at any position x away from the emulsion pump station. x =f(x, p0); Pipeline pressure transmission time Δt at any position x from the emulsion pump station x =x / v x , v x =f(x,v);

[0089] Input the distance x between the current actuator and the emulsion pump station to obtain the pressure loss Δp at the current hydraulic support execution point. x The pipeline pressure transmission time Δt at the current hydraulic support execution point x ;

[0090] The pressure loss Δp at the current hydraulic support execution point x , the pipeline pressure transmission time Δt at the current hydraulic support execution point x , the outlet pressure of the emulsion pump station, and the basic parameters of the current actuator are input into the flow solver to obtain the flow value that meets the outlet pressure control target of the liquid supply system in the future and the advance liquid supply time (i.e., Δt x );

[0091] The flow value output by the flow solver to meet the outlet pressure control target of the fluid supply system in the future period of time is compared with the lead fluid supply time (i.e., Δt x) as the flow control actuator input, and obtain the flow value of the parallel pump control / flow valve bypass advance adjustment;

[0092] When it is detected that the action executed by the hydraulic support is consistent with the type in the database, the corresponding emulsion pump station outlet pressure, hydraulic support end pressure, emulsion pump station liquid supply status, and hydraulic support end liquid status data are called according to the switch signal of the hydraulic support electromagnetic reversing valve;

[0093] According to the distance calculation method between the current actuator and the emulsion pump station, the distance between the current actuator and the emulsion pump station (x+s) is obtained, where s is the interval distance between two adjacent groups of brackets;

[0094] According to the current hydraulic support load estimation method, the current hydraulic support load (F i+1 );

[0095] The current state of x+s and F i+1 Input the long-distance liquid supply pipeline model to obtain the pipeline pressure p at any position x+s away from the emulsion pump station under the current operating state. x+s =f(x+s, p0); Pipeline pressure transmission time Δt at any position x+s from the emulsion pump station x+s =x+s / v x , v x+s =f( x+s , v); obtain the pipeline pressure transmission time (Δt x+s ) and the pressure loss (Δp x+s ), bring it into the flow solver to update the output;

[0096] According to the flow solver update in the future to meet the outlet pressure control target of the liquid supply system flow value and the leading liquid supply time (i.e. Δt x+s ), bring it into the flow control actuator to obtain the corresponding parallel pump control / flow valve bypass advance adjustment flow value;

[0097] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with the technology to understand the content of the present invention and implement it accordingly, and they cannot be used to limit the protection scope of the present invention. All equivalent changes and modifications made according to the essence of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for pressure-stabilized liquid supply by model prediction control of a hydraulic support liquid supply system, characterized in that: Here are the steps: Obtain the number of all hydraulic supports in the entire hydraulic support fluid supply system, the cylinder diameter of each actuator of the hydraulic support, the rod diameter of each actuator of the hydraulic support, and the designed action speed as basic parameters; A hydraulic support fluid supply system model is constructed according to the hydraulic support fluid supply system. The hydraulic support fluid supply system model includes a large inertia emulsion pump model, an accumulator model and an unloading valve model for digitally simulating an emulsion pump station, a long-distance fluid supply pipeline model for digitally simulating a long-distance fluid supply pipeline, a hydraulic support electromagnetic reversing valve group model and a hydraulic support emulsion cylinder model for digitally simulating a hydraulic support; wherein the large inertia emulsion pump model is connected to the long-distance fluid supply pipeline model through the accumulator model and the unloading valve model, and the long-distance fluid supply pipeline model is respectively connected to the hydraulic support electromagnetic reversing valve group model and the hydraulic support emulsion cylinder model; the hydraulic support fluid supply system model can derive the execution action information of the current hydraulic support by reading the electromagnetic reversing valve switch signals on all hydraulic supports in the hydraulic support fluid supply system; Construct a flow solver to calculate the flow value that meets the outlet pressure control target of the fluid supply system and the lead fluid supply time of the current hydraulic support action; The distance between the hydraulic support currently executing the action and the emulsion pump station is calculated to obtain the distance x between the current hydraulic support and the emulsion pump station. i ; The current hydraulic support load force F is obtained by the hydraulic support load force estimation method i ; According to the basic parameters of the hydraulic support fluid supply system, the distance x between the current hydraulic support and the emulsion pump station i and the current hydraulic support load F i Input the hydraulic support fluid supply system model, so that the hydraulic support fluid supply system model outputs the system parameter information corresponding to the hydraulic support action state: emulsion pump station outlet pressure / pipeline inlet pressure, hydraulic support end pressure / pipeline outlet pressure, emulsion pump station fluid supply state / unloading valve state, hydraulic support end fluid use state / hydraulic support electromagnetic reversing valve switch signal; The output of the hydraulic support fluid supply system model is input into the long-distance fluid supply pipeline model to obtain the pipeline pressure p at any position x from the emulsion pump station in the current action state. x =f(x, p0); Pipeline pressure transmission time Δt at any position x from the emulsion pump station = x / v x , v x =f(x, v); v x is the average flow velocity of the fluid in the pipeline, and v is the outlet flow velocity of the emulsion pump station; Substitute the current distance x between the hydraulic support and the emulsion pump station into p x =f(x, p0) and Δt=x / v x , v x =f(x, v), and the pressure loss Δp at the current hydraulic support execution point is obtained x The pipeline pressure transmission time Δt at the current hydraulic support execution point x ; The pressure loss Δp at the current hydraulic support execution point x , the pipeline pressure transmission time Δt at the current hydraulic support execution point x , the outlet pressure of the emulsion pump station, and the basic parameters of the hydraulic support in the current action are input into the flow solver to obtain the flow value that meets the control target of the outlet pressure of the emulsion pump station and the advance liquid supply time Δt under the current hydraulic support action when the hydraulic support performs the next action a ; The predicted flow value and the advance liquid supply time Δt a The flow regulating actuator is input to obtain the parallel pump control / flow valve bypass advance regulating flow value, and the parallel pump control / flow valve bypass advance regulating flow value is used to advance regulate the flow.

2. The method for pressure-stabilized liquid supply by model predictive control of a hydraulic support liquid supply system according to claim 1, characterized in that: The specific steps are as follows: A working cycle of the hydraulic support in the working face includes pushing the conveyor, lowering the frame, pulling the frame, raising the frame and protecting the side. Therefore, the flow and pressure of the hydraulic support fluid supply system in the working process of the hydraulic support have weak periodic characteristics. A hydraulic support fluid supply system parameter database of the hydraulic support in the process of executing the action is established to record the outlet pressure of the emulsion pump station, the pressure at the emulsion cylinder end of the hydraulic support, the fluid supply status of the emulsion pump station and the fluid status data of the emulsion cylinder end of the hydraulic support during each working cycle of the hydraulic support in the working face; The switch signal of the electromagnetic reversing valve of the hydraulic support is used to judge the execution action of the hydraulic support. When it is detected that the current execution action of the hydraulic support is inconsistent with the action type recorded in the parameter database of the hydraulic support fluid supply system, the current action hydraulic support execution action is obtained according to the switch signal of the electromagnetic reversing valve of the current hydraulic support, and the basic parameters of the hydraulic support fluid supply system are obtained; the distance x between the current hydraulic support and the emulsion pump station is calculated; and the current hydraulic support load force F is estimated. i ; The basic parameters of the hydraulic support fluid supply system and the distance x between the hydraulic support and the emulsion pump station i , hydraulic support load F i Input the hydraulic support fluid supply system model, and output the outlet pressure of the emulsion pump station, the pressure at the end of the hydraulic support, the fluid supply status of the emulsion pump station, and the switch signal of the electromagnetic reversing valve of the hydraulic support after simulation of the hydraulic support fluid supply system model; Using the long-distance liquid supply pipeline model, according to the distance x between the hydraulic support and the emulsion pump station, the current hydraulic support load F i , calculate the pressure p in the pipeline at any position x away from the emulsion pump station x =f(x, p0); Pipeline pressure transmission time Δt at any position x from the emulsion pump station x =x / v x , v x =f(x,v); Input the distance x between the current hydraulic support and the emulsion pump station to obtain the pressure loss Δp at the current hydraulic support execution point. x The pipeline pressure transmission time Δt at the current hydraulic support execution point x ; The pressure loss Δp at the current hydraulic support execution point x , the pipeline pressure transmission time Δt at the current hydraulic support execution point x , the outlet pressure of the emulsion pump station, and the basic parameters of the hydraulic support in the current action are input into the flow solver to obtain the flow value that meets the control target of the outlet pressure of the emulsion pump station and the advance liquid supply time Δt under the current hydraulic support action when the hydraulic support performs the next action a ; The flow value that satisfies the hydraulic support to perform the next action and the advance fluid supply time under the current hydraulic support action, i.e., Δt a Input flow regulating actuator, through which the parallel pump control / flow valve bypass is controlled to adjust the flow in advance; When it is detected that the current execution action of the hydraulic support is consistent with the action type recorded in the hydraulic support fluid supply system parameter database, the corresponding emulsion pump station outlet pressure, hydraulic support end pressure, emulsion pump station fluid supply status, and hydraulic support end fluid status data are called according to the hydraulic support electromagnetic reversing valve switch signal; According to the current distance calculation method between the hydraulic support and the emulsion pump station, the current distance x between the hydraulic support and the emulsion pump station is obtained; according to the current hydraulic support load force estimation method, the current hydraulic support load force F in the long-distance liquid supply pipeline model input is obtained i ; The current state of x and F i Input the long-distance liquid supply pipeline model to obtain the pipeline pressure p at any position x from the emulsion pump station under the current operating state. x =f(x, p0); Pipeline pressure transmission time Δt at any position x from the emulsion pump station x =x / v x , v x =f(x, v); get the pipeline pressure transmission time Δt corresponding to the distance x between the current hydraulic support and the emulsion pump station x The pressure loss Δp at the current hydraulic support execution point is brought into the flow solver to update the output; According to the flow solver update in the future to meet the outlet pressure control target of the fluid supply system flow value and the advance fluid supply time Δt under the current hydraulic support action a , input flow control actuator, and control the parallel pump control / flow valve bypass through the flow control actuator to adjust the flow in advance.

3. The method for pressure-stabilized liquid supply by model predictive control of a hydraulic support liquid supply system according to claim 1, characterized in that: The specific working process of the flow regulating actuator is as follows: replenishing the liquid in parallel through the replenishing pump to quickly increase the maximum liquid supply flow of the emulsion pump station, and reducing the liquid supply flow of the emulsion pump station through bypass throttling of the flow valve. According to the flow value obtained by the flow solver and the pressure transmission time of the long-distance liquid supply pipeline, the flow regulation is performed in advance: by increasing or reducing the output flow of the emulsion pump station in advance, the lag caused by the pressure transmission is compensated.

4. The method for pressure-stabilized liquid supply by model predictive control of a hydraulic support liquid supply system according to claim 1, characterized in that: The input signal value of the long-distance liquid supply pipeline model has the characteristic of being adjusted according to the switch signal of the electromagnetic reversing valve of the hydraulic support; according to the electromagnetic reversing valve signal of the hydraulic support, the long-distance liquid supply pipeline model is used to calculate the distance between the current hydraulic support and the emulsion pump station. The specific calculation method is as follows: Assume that the hydraulic support currently in action is numbered m in the hydraulic support group, and the distance between the current hydraulic support and the emulsion pump station is x. m = length of chute pipeline + (m-1) * spacing between racks.

5. The method for pressure-stabilized liquid supply by model predictive control of a hydraulic support liquid supply system according to claim 1, characterized in that: The current hydraulic support load force estimation method is as follows: According to the current hydraulic support action type, when the load force F is first applied to a certain action during the hydraulic support cycle, i When estimating, analyze the stress conditions and characteristics of the corresponding action process of the hydraulic support, analyze the friction resistance between the hydraulic support and the working face roof, coal wall, and ground according to the current hydraulic support action type, and calculate the current hydraulic support load force F according to the stress analysis. i To estimate, when it is not the first time to perform a load force F on an execution action i When estimating, the Coulomb pressure model is used to calculate the load on the support. At this time, F i =C*P avg *A, where C is the empirical coefficient, P avg is the average outlet pressure of the emulsion pump station, and A is the effective area of ​​the emulsion cylinder on the hydraulic support.

6. The method for pressure-stabilized liquid supply by model predictive control of a hydraulic support liquid supply system according to claim 1, characterized in that: The model predictive control and pressure stabilizing fluid supply method of the hydraulic support fluid supply system has the characteristics of parameter updating. The model update cycle is divided according to the different action times of the hydraulic support, and the total time for the hydraulic support to perform one push-conveyance, frame lowering, frame moving, frame lifting and side protection action is taken as the model update cycle, and the measured pressure of the fluid supply system during each cycle action is recorded. When the model is updated, the predicted outlet pressure of the hydraulic support emulsion pump station is obtained according to the switching signal of the hydraulic support electromagnetic reversing valve, and compared with the corresponding pressure segment in the measured periodic pressure data of the hydraulic support fluid supply system of the comprehensive mining working face. According to the pressure difference, the parameters of the mean pressure change rate in the hydraulic support fluid supply system model and the flow solver are adjusted and optimized to improve the accuracy of the hydraulic support fluid supply system model for pressure prediction.

7. The method for pressure-stabilized liquid supply by model predictive control of a hydraulic support liquid supply system according to claim 1, characterized in that: In the entire hydraulic support fluid supply system model, the emulsion flowing in the pipeline needs to consider the friction term correction, and the dynamic evolution conforms to the high-pressure, large-flow turbulent non-steady flow pipeline equation corrected by the Brunone additional friction model, which is expressed as follows: Wherein, g is the acceleration of gravity, H is the relative height difference of the pipeline, v is the flow velocity of the fluid in the pipeline, a is the pressure wave velocity, k3 is the Brunone friction coefficient, f is the friction coefficient in the pipeline, θ is the angle between the pipeline and the horizontal line, and D is the diameter of the pipeline; The influence of the turbulent state in the pipeline and the strong time-varying load on the characteristics of the long pipeline is considered through the high-pressure, large-flow turbulent unsteady flow pipeline equation, and the friction term of the emulsion in the pipeline is corrected.

8. The method for pressure-stabilized liquid supply by model predictive control of a hydraulic support liquid supply system according to claim 1, characterized in that: The long-distance liquid supply pipeline model is used to solve the pressure at any point in the pipeline: The pressure in the pipeline at any position x from the emulsion pump station in the entire working surface: p x =f(x, p0), where x is the distance from a point on the pipeline to the emulsion pump station, and p0 is the outlet pressure of the emulsion pump station; The pressure loss Δp at any position x in the entire working face from the emulsion pump station x =p0-p x ; The pipeline pressure transmission time at any position x from the emulsion pump station in the entire working surface is: Δt x =x / v x ,v x =f(x,v), Among them, v x is the average flow velocity of the fluid in the pipeline, and v is the outlet flow velocity of the emulsion pump station; The pipeline pressure transmission time Δt at any position x from the emulsion pump station in the entire working face x =x / v x , and Δp x , Δt x As input to the flow solver model.

9. The method for pressure-stabilized liquid supply by model predictive control of a hydraulic support liquid supply system according to claim 1, characterized in that: The flow required for the hydraulic support actuator to operate includes three parts: the flow of the accumulator during the entire hydraulic support operation process. The accumulator is a component in the emulsion pump station. It can adjust its output flow according to the pressure of the hydraulic support fluid supply system and play a role in absorbing the impact in the hydraulic support fluid supply system; The flow rate provided by emulsion compression during the entire hydraulic support action process; During the entire process of the hydraulic support, the emulsion cylinder movement and load influence generate flow, which is the flow required for the smooth movement of the actuator; The flow calculation method using the flow solver to solve the flow generated by the accumulator during the execution of the hydraulic support is: Among them, P u is the unloading pressure of the unloading valve, P d is the unloading valve recovery pressure, P0 is the accumulator initial pressure, V0 is the accumulator initial volume, Paˊ is ​​the rate of change of the pressure curve in the accumulator supply stage, ΔV g This is the volume change of the pipeline during this process, and βe is the elastic bulk modulus of the emulsion; The calculation formula for the flow rate caused by the emulsion compression is: Among them, P in is the outlet pressure of the emulsion pump station, Δp is the dynamic pressure loss from the outlet of the emulsion pump station to the emulsion cylinder end of the hydraulic support, V is the pipeline volume from the outlet of the emulsion pump station to the emulsion cylinder end of the hydraulic support, β e is the bulk modulus of the emulsion; The calculation formula for the flow rate generated by the emulsion cylinder action and load influence is: Among them, A A A is the side area of ​​the hydraulic cylinder entering the liquid, B is the liquid return side area of ​​the hydraulic cylinder, P A is the pressure on the hydraulic cylinder inlet side, P B is the pressure on the return side of the hydraulic cylinder, M is the equivalent mass of the actuator, and F is the load force; The flow solver outputs the flow value q required for the hydraulic support actuator to move, which is the sum of the above three flow rates. The flow solver output flow calculation formula is: q=q x +q c +q d 。

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