A hydraulic support liquid supply system model predictive control constant pressure liquid supply method

Abstract

The application provides a hydraulic support liquid supply system model predictive control pressure stabilizing liquid supply method, and belongs to the technical field of intelligent control of fully mechanized working face liquid supply systems. The liquid supply system parameters are obtained by constructing a hydraulic support liquid supply system model, and the distance of the current execution action hydraulic support group from the emulsion pump station is determined by the electromagnetic switch state of the reversing valve of each actuator of the hydraulic support. The liquid supply system parameters and the distance of the current execution action hydraulic support group from the emulsion pump station are input into the long-distance liquid supply pipeline model to obtain the pressure loss and the pipeline pressure transmission time at the current hydraulic support execution action position. The flow solver is used to obtain the flow value that meets the emulsion pump station outlet pressure control target when the hydraulic support executes the next action, the advance liquid supply time under the current hydraulic support action, and the advance adjustment flow value. The method has simple steps, is convenient to use, and can quickly and accurately match the emulsion pump station liquid supply end and the actuator liquid demand end.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of pressure control of a fully-mechanized coal mining face liquid supply system, and particularly relates to a hydraulic support liquid supply system model predictive control stable pressure supply method. BACKGROUND

[0002] With the development of the hydraulic support of the fully-mechanized coal mining face, higher requirements are put forward for the output capacity of the underground liquid supply system, and the remote transmission stable pressure and flow control technology becomes a key technology that needs to be broken through. The liquid supply system of the hydraulic support of the fully-mechanized coal mining face has the characteristics of high pressure and large flow and long pipeline liquid supply. In order to meet the working requirements of the quick following of the coal mining machine, the hydraulic support group quickly executes the work, and the numerous actuators frequently act in time, and in addition, the load of the coal mining face frequently changes, which leads to the strong time-varying pressure fluctuation of the liquid supply system, the poor stable pressure effect, and the difficulty in guaranteeing the production efficiency and the equipment reliability of the fully-mechanized coal mining face.

[0003] The hydraulic support has the characteristics of time-sharing group work, and the main actions include the pushing and conveying, the lowering of the support, the moving of the support, the lifting of the support, and the support protection, and with the continuous action of the hydraulic support of the working face, the liquid supply distance of the working face also changes with the position change of the hydraulic support of the execution action, and has a certain weak periodicity. Therefore, the pressure and the flow in the action process have certain periodic evolution characteristics. In view of the characteristics, the existing prediction is mostly made from the support action category, and the simple static flow demand analysis is made, and the liquid supply system and the pipeline characteristics are not interacted, and it is difficult to dynamically determine the flow regulation target of the liquid supply system in real time.

[0004] Therefore, a stable pressure control strategy is proposed: a fully-mechanized coal mining face hydraulic support liquid supply system model predictive control stable pressure method based on the liquid supply system model pressure prediction and the parallel pump control / flow valve control flow regulation mode, so as to accurately and quickly supply liquid to the working face, guarantee that the liquid supply flow can meet the action demand in time, improve the response speed of the liquid supply system, reduce the pressure impact of the liquid supply system, and improve the stable pressure effect of the working face. SUMMARY

[0005] In view of the deficiencies of the prior art, a hydraulic support liquid supply system model predictive control stable pressure supply method is provided, the influence of the long distance liquid supply on the dynamic transmission characteristics of the system is considered, the dynamic evolution characteristics of the whole system are analyzed, the pressure response relationship and the pressure lag time caused by the long distance liquid supply pipeline are accurately obtained, and then the real-time leading liquid supply matching relationship between the liquid supply flow and the actuator liquid demand flow is obtained, so as to effectively improve the matching speed and precision between the liquid supply flow of the hydraulic support liquid supply system and the liquid demand of the hydraulic support emulsion cylinder end, reduce the pressure impact of the system, and improve the stable pressure effect of the liquid supply system.

[0006] In order to realize the above technical purpose, the hydraulic support liquid supply system model predictive control pressure stabilizing liquid supply method comprises the following steps:

[0007] Obtain the number of all hydraulic supports in the whole hydraulic support liquid 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 as basic parameters;

[0008] Construct a hydraulic support liquid supply system model according to the hydraulic support liquid supply system, wherein the hydraulic support liquid supply system model comprises a large-inertia emulsion pump model for digitally simulating an emulsion pump station, an accumulator model and an unloading valve model, a long-distance liquid supply pipeline model for digitally simulating a long-distance liquid supply pipeline, a hydraulic support electromagnetic reversing valve group model for digitally simulating a hydraulic support and a hydraulic support emulsion oil cylinder model; the large-inertia emulsion pump model is connected with the long-distance liquid supply pipeline model through the accumulator model and the unloading valve model, and the long-distance liquid supply pipeline model is connected with the hydraulic support electromagnetic reversing valve group model and the hydraulic support emulsion oil cylinder model; the hydraulic support liquid supply system model can deduce the execution action information of the current hydraulic support by reading the electromagnetic reversing valve switch signal of all hydraulic supports in the hydraulic support liquid supply system;

[0009] Construct a flow solver for calculating the flow value meeting the control target of the outlet pressure of the liquid supply system and the flow time of the current hydraulic support action;

[0010] Calculate the distance x between the current hydraulic support and the emulsion pump station through the distance between the current execution action hydraulic support and the emulsion pump station, i obtain the current hydraulic support load force F through a hydraulic support load force estimation method, i input the hydraulic support liquid supply system model according to the obtained hydraulic support liquid supply system basic parameters, the distance x between the current hydraulic support and the emulsion pump station and the current hydraulic support load force F i , so that the hydraulic support liquid supply system model outputs the system parameter information in the corresponding hydraulic support action state: the emulsion pump station outlet pressure / pipeline inlet pressure, the hydraulic support end pressure / pipeline outlet pressure, the emulsion pump station liquid supply state / unloading valve state, the hydraulic support end liquid state / hydraulic support electromagnetic reversing valve switch signal;

[0011] Input the output of the hydraulic support liquid supply system model into the long-distance liquid supply pipeline model to obtain the pipeline internal pressure p at any position x from the emulsion pump station in the current action state, x f(x, p0); the pipeline pressure transmission time Δt at any position x from the emulsion pump station is x / v x , v x =f(x, v); v x is the average flow rate of the fluid in the pipeline, and v is the outlet flow rate 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), which gives the pressure loss Δp at the point where the hydraulic support is performing its action. x The pipeline pressure transmission time Δt at the current hydraulic support's point of action x ;

[0013] The pressure loss Δp at the current hydraulic support's operating point x The pressure transmission time Δt in the pipeline at the point where the hydraulic support is performing its action. x The emulsion pump station outlet pressure and the current hydraulic support basic parameter input flow solver predict the flow rate value that meets the outlet pressure control target of the supply system in the next time period and the advance supply time Δt under the current hydraulic support operation. a ;

[0014] The predicted flow rate and the advance fluid supply time Δt a Input the flow regulating actuator to obtain the parallel pump control / flow valve bypass advance regulation flow value, and use the parallel pump control / flow valve bypass advance regulation flow value to advance the flow.

[0015] The specific steps are as follows:

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

[0017] The operating action of the hydraulic support is determined by using the switching signal of the solenoid directional valve of the hydraulic support.

[0018] When the current action of the hydraulic support is detected to be inconsistent with the action type recorded in the hydraulic support supply system parameter database, the current action of the hydraulic support is obtained based on the current solenoid directional valve switching signal, and the basic parameters of the hydraulic support supply system are obtained; the distance x between the current hydraulic support and the emulsion pump station is calculated; and the load force F of the current hydraulic support 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 are specified. i Hydraulic support load force Fi The hydraulic support liquid supply system model is inputted, and the emulsion pump station outlet pressure, the hydraulic support end pressure, the emulsion pump station liquid supply state, and the hydraulic support electromagnetic reversing valve switch signal are outputted after simulation by the hydraulic support liquid supply system model;

[0020] The distance x between the current hydraulic support and the emulsion pump station and the current hydraulic support load force F i are inputted into the long-distance liquid supply pipeline model, and the pipeline internal pressure p x at any position x from the emulsion pump station is calculated as f(x, p0), the pipeline pressure transmission time Δt x at any position x from the emulsion pump station is calculated as x / v x , and v x is calculated as f(x, v);

[0021] The distance x between the current hydraulic support and the emulsion pump station is inputted, and the pressure loss Δp x at the position where the current hydraulic support performs an action and the pipeline pressure transmission time Δt x at the position where the current hydraulic support performs an action are obtained;

[0022] The pressure loss Δp x at the position where the current hydraulic support performs an action, the pipeline pressure transmission time Δt x at the position where the current hydraulic support performs an action, the emulsion pump station outlet pressure, and the basic parameter input flow of the current action hydraulic support are inputted into the flow solver, and the flow value that meets the emulsion pump station outlet pressure control target when the hydraulic support performs the next action and the advance liquid supply time Δt a under the current hydraulic support action are obtained;

[0023] The flow value that meets the hydraulic support performing the next action and the advance liquid supply time Δt a under the current hydraulic support action are inputted into the flow regulation actuator, and the flow regulation is controlled in advance by the flow regulation actuator through the parallel pump control / flow valve bypass;

[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 liquid supply system parameter database, the corresponding emulsion pump station outlet pressure, hydraulic support end pressure, emulsion pump station liquid supply state, and hydraulic support end liquid state data are called according to the hydraulic support electromagnetic reversing valve switch signal;

[0025] The distance x between the current hydraulic support and the emulsion pump station is obtained according to the distance calculation method between the current hydraulic support and the emulsion pump station, and the current hydraulic support load force F i is obtained according to the current hydraulic support load force estimation method;

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

[0027] According to the flow value satisfying the supply system outlet pressure control target in the future period of time updated by the flow solver and the advance supply time Δt under the current hydraulic support action a , input the flow regulation actuator, and control the parallel pump control / flow valve bypass to advance flow regulation.

[0028] Further, the flow regulation actuator workflow is specifically: parallel liquid supplementing by the liquid supplementing pump to quickly increase the maximum supply flow of the emulsion pump station, throttling by the flow valve bypass to reduce the supply flow of the emulsion pump station, and advance flow regulation according to the flow value obtained by the flow solver and the pressure transmission time of the long-distance supply pipeline: advance increase or decrease of the output flow of the emulsion pump station to make up for the lag caused by pressure transmission.

[0029] Further, the long-distance supply pipeline model input signal value has the characteristic of being adjusted according to the on-off signal of the hydraulic support electromagnetic reversing valve; according to the signal of the hydraulic support electromagnetic reversing valve, the distance between the current hydraulic support and the emulsion pump station is calculated by using the long-distance supply pipeline model, and the specific calculation method is as follows:

[0030] Suppose that the current action hydraulic support is numbered m in the hydraulic support group, and the distance x between the current hydraulic support and the emulsion pump station is m = length of the crossheading pipeline + (m-1)*inter-support spacing.

[0031] Further, the current hydraulic support load force estimation method is as follows: according to the action type of the current hydraulic support, when estimating the load force F i for the first time in the process of a certain action of the hydraulic support, analyze the force conditions and corresponding action process characteristics of the corresponding hydraulic support executing action, analyze the frictional resistance of the current hydraulic support executing action type to the working face roof, coal wall and ground according to the force analysis, and estimate the load force F i for the first time in the process of a certain action of the hydraulic support, analyze the force conditions and corresponding action process characteristics of the corresponding hydraulic support executing action, analyze the frictional resistance of the current hydraulic support executing action type to the working face roof, coal wall and ground according to the force analysis, and estimate the load force F iIn the estimation, the load borne by the support is calculated by using the Coulomb mine pressure model, and F i =C*P avg *A, where C is an empirical coefficient, P avg is the average pressure at the outlet of the emulsion pump station, and A is the effective area of the emulsion cylinder of the hydraulic support.

[0032] Further, the hydraulic support liquid supply system model predictive control pressure stabilization liquid supply method has a parameter updating feature; the model updating cycle is divided according to different action times of the hydraulic support, the total time of the hydraulic support performing one-time push conveying, lowering, moving and raising actions is taken as the updating cycle of the model, and the measured pressure of the liquid supply system in each cycle action process is recorded; when the model is updated, the predicted emulsion pump station outlet pressure of the hydraulic support is obtained according to the switch signal of the electromagnetic reversing valve of the hydraulic support, and the corresponding pressure segment in the measured cycle pressure data of the hydraulic support liquid supply system in the fully mechanized coal mining face is compared; according to the pressure difference, the mean pressure change rate parameter in the hydraulic support liquid supply system model and the flow solver is adjusted and optimized, and the accuracy of the pressure prediction of the hydraulic support liquid supply system model is improved.

[0033] Further, the friction term correction needs to be considered for the emulsion flowing in the pipeline in the entire hydraulic support liquid supply system model, and the dynamic evolution conforms to the high-pressure and large-flow turbulent unsteady flow pipeline equation corrected by the Brunone additional friction model, and 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 pipeline friction coefficient, θ is the horizontal line angle of the pipeline, and D is the pipeline diameter.

[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 by the high-pressure and large-flow turbulent unsteady flow pipeline equation, and the friction term correction of the emulsion in the pipeline is performed.

[0037] Further, the pressure at any point in the long-distance liquid supply pipeline is solved by using the long-distance liquid supply pipeline model:

[0038] The pressure in the pipeline at any position x away from the emulsion pump station in the entire working face is p x =f(x, p0), wherein x is the distance of a certain point on the pipeline from the emulsion pump station, and p0 is the outlet pressure of the emulsion pump station.

[0039] The pressure loss Δp x of the pipeline at any position x away from the emulsion pump station in the entire working face is p0-p x .

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

[0041] Δt = x / v x x , v x = f(x, v),

[0042] Wherein, x is the distance of a certain point on the pipeline from the emulsion pump station, v x is the average flow rate of the fluid in the pipeline, and v is the flow rate at the outlet of the emulsion pump station;

[0043] The pipeline pressure transmission time Δt at any position x from the emulsion pump station in the whole working face is: x x Δt = x / v x , Δp x , Δt u are taken as inputs of the flow solver model.

[0044] Further, the flow required for the action of the hydraulic support actuator includes three parts: the flow provided by the accumulator during the whole hydraulic support actuation process, the accumulator being an element in the emulsion pump station and being capable of adjusting its output flow according to the pressure of the hydraulic support liquid supply system to absorb the impact in the hydraulic support liquid supply system; the flow provided by the emulsion compression during the whole hydraulic support actuation process; and the flow generated by the action of the emulsion cylinder and the load during the whole hydraulic support actuation process, which is the flow required for the smooth movement of the actuator.

[0045] The calculation method of the flow generated by the accumulator during the hydraulic support actuation process by using the flow solver is:

[0046]

[0047] Wherein, P u is the unloading pressure of the unloading valve, P d is the recovery pressure of the unloading valve, P0 is the initial pressure of the accumulator, V0 is the initial volume of the accumulator, Paˊ is the pressure curve change rate of the accumulator during the liquid supply stage, ΔV g is the change volume of the pipeline during the process, and βe is the elastic volume modulus of the emulsion.

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

[0049]

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

[0051] The calculation formula of the flow affected by the action and load of the emulsion oil cylinder is:

[0052]

[0053] wherein, A A is the inlet area of the hydraulic cylinder, A B is the return area of the hydraulic cylinder, P A is the inlet pressure of the hydraulic cylinder, P B is the return pressure of the hydraulic cylinder, m is the equivalent mass of the actuator, and F is the load force;

[0054] The flow required by the actuator of the hydraulic support is the sum of the above three flows, and the flow calculation formula of the flow solver is:

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

[0056] Beneficial effects: based on the multi-pump configuration liquid supply, the hydraulic support liquid supply system model is established, and through the long-distance liquid supply pipeline model, the dynamic pressure loss Δp x and the pipeline pressure transmission time Δt x under the current actuation are calculated in real time and compensated, and the hydraulic support liquid supply system model and the flow solver have the parameter updating feature, which can continuously improve the accuracy of the output of the hydraulic support liquid supply system model, improve the matching speed and precision between the liquid supply flow of the hydraulic support liquid supply system and the required liquid amount of the hydraulic support emulsion oil cylinder end, reduce the pressure impact of the system, and improve the pressure stabilizing effect of the liquid supply system. In addition, by establishing the parameter database of the hydraulic support liquid supply system, according to the switching signal of the electromagnetic reversing valve of the hydraulic support, the required liquid supply flow of the current hydraulic support actuation is predicted in advance, the delay time of the hydraulic support liquid supply system is reduced, and the response characteristics of the hydraulic support liquid supply system are improved. BRIEF DESCRIPTION OF DRAWINGS

[0057] Figure 1 is a schematic diagram of the hydraulic support liquid supply system model of the present application;

[0058] Figure 2 is a flow chart of the prediction control pressure stabilizing liquid supply method in the embodiment of the present application;

[0059] Figure 3 is a schematic diagram of the long-distance liquid supply pipeline model of the embodiment of the present application;

[0060] Figure 4 This is a schematic diagram illustrating the parameter update process of the hydraulic support fluid supply system model in an embodiment of the present invention. Detailed Implementation

[0061] The embodiments of the present invention will be further described below with reference to the accompanying drawings:

[0062] like Figure 1 As shown, this 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. The emulsion pump station model includes a high-inertia emulsion pump model, an accumulator model, and an unloading valve model. The high-inertia emulsion pump model can be categorized into pumps 1, 2, etc., based on the actual number of emulsion pumps, with the theoretical output flow rate d. The influence of the emulsion pump station's outlet pressure on the output flow rate is simulated using the fluid conductivity coefficient. The accumulator model is based on the actual... The flow rate of the accumulator under charging and discharging states is simulated; the unloading valve model, based on the actual unloading valve structure, determines the opening and closing of the main valve of the unloading valve through the opening and closing state of the pilot valve, thereby determining whether the emulsion pump station outlet flow enters the working face or flows back to the oil tank from the unloading valve; the hydraulic support solenoid directional valve group model, based on the actual hydraulic support solenoid directional valve, simulates the flow rate corresponding to the opening and closing states of multiple sets of hydraulic support solenoid directional valves; the hydraulic support actuator model, based on the characteristics of the actual hydraulic support actuator cylinder, establishes the flow continuity equation and force balance equation of the hydraulic support emulsion cylinder to simulate the motion state of the hydraulic support emulsion cylinder.

[0063] like Figure 4 As shown, the hydraulic support fluid supply system model has the following characteristics: The hydraulic support fluid supply system model uses the switching signal of the hydraulic support solenoid directional valve as the input signal, and calculates the current distance x between the actuator and the emulsion pump station using the distance calculation method between the actuator and the emulsion pump station. i Using the current hydraulic support load capacity estimation method, the current hydraulic support load capacity F is obtained. i By analyzing the actions performed by the hydraulic support, parameters such as the number of actuators, cylinder diameter, and rod diameter of the hydraulic support fluid supply system are obtained, thereby determining the hydraulic support fluid supply system model under the current execution state. The system outputs the emulsion pump station outlet pressure (pipeline outlet pressure), hydraulic support end pressure (pipeline inlet pressure), emulsion pump station fluid supply status (unloading valve switch signal), and hydraulic support end fluid usage status (hydraulic support solenoid directional valve switch signal) as inputs to the long pipeline fluid supply model.

[0064] The distance x between the current 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 fully mechanized coal mining face contains n hydraulic supports, usually n can reach dozens to hundreds, the distance between each hydraulic support is determined, then the distance between any hydraulic support of the working face and the emulsion pump station can be determined by the length of the crossheading pipeline + (n-1)*support spacing, according to the electromagnetic switch signal of the hydraulic support, the number of the current action hydraulic support in the hydraulic support group is determined, thereby the distance between the current actuator and the emulsion pump station in the long-distance liquid supply pipeline model input is determined, assuming that the number of the current action hydraulic support in the hydraulic support group is m, the distance x between the current actuator and the emulsion pump station is m = length of crossheading pipeline + (m-1)*support spacing.

[0065] The current hydraulic support load estimation method is as follows: according to the action type of the current hydraulic support, when the load force F i is estimated for the first time in the periodic action process of a certain action, the force condition and the corresponding action process characteristics of the corresponding hydraulic support are analyzed, the frictional resistance of the current hydraulic support to the working face roof, coal wall and ground is analyzed according to the type of the action performed by the current hydraulic support, and the load force F i of the current hydraulic support is estimated according to the force analysis, when the load force F i is estimated for the first time in the periodic action process of a certain action, the load of the support is calculated by using the Coulomb mine pressure model, at this time F i =C*P avg *A, wherein C is an empirical coefficient, P avg is the average pressure at the outlet 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 considers the influence of the turbulent state in the pipeline and the strong time-varying load on the characteristics of the long pipeline, and the friction term is modified according to the working condition characteristics, so that the pressure dynamic change law of the support liquid supply system with long pipeline, high pressure and large flow, and strong time-varying load characteristics can be mastered. The high-pressure and large-flow turbulent unsteady flow pipeline equation modified by the Brunone additional friction model is included:

[0067]

[0068] 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 pipeline internal friction coefficient, θ is the angle between the pipeline and the horizontal line, and D is the pipeline diameter.

[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. The long-distance liquid supply pipeline model is as follows:Figure 3 As shown in the equation group, the equation group is transformed by finite difference and takes current hydraulic support load force F i , emulsion pump station outlet pressure (pipeline inlet pressure), hydraulic support end pressure (pipeline outlet pressure), emulsion pump station liquid supply state (unloading valve switch signal) and hydraulic support end liquid state (hydraulic support electromagnetic reversing valve switch signal) as input; output the pipeline internal pressure p x of the entire working surface at any position x from the emulsion pump station x = f(x, p0), where x is the distance of a certain point on the pipeline from the emulsion pump station, p0 is the outlet pressure of the emulsion pump station, and the pressure loss Δp x of the entire working surface at any position x from the emulsion pump station can be obtained x = p0-p x , v x = f(x, v), where x is the distance of a certain point on the pipeline from the emulsion pump station, v x is the average flow rate of the fluid in the pipeline, and v is the outlet flow rate of the emulsion pump station, and the pipeline pressure transmission time Δt x of the entire working surface at any position x from the emulsion pump station can be obtained x = x / v x , and Δp x , Δt u are taken as input of the flow solver model, as shown in Figure 3 .

[0070] The flow solver has the following characteristics:

[0071] The calculation formula of the accumulator flow under the emulsion pump station liquid supply stage is:

[0072]

[0073] Where P d is the unloading pressure of the unloading valve, P g is the recovery pressure of the unloading valve, P0 is the initial pressure of the accumulator, V0 is the initial volume of the accumulator, Paˊ is the pressure curve change rate of the accumulator liquid supply stage, ΔV e is the pipe volume change in this process, and β in is the elastic volume modulus of the emulsion;

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

[0075]

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

[0077] The calculation formula of the flow generated by the actuator action and the load influence is:

[0078]

[0079] Wherein, A A is the hydraulic cylinder inlet area, A B is the hydraulic cylinder return area, P A is the hydraulic cylinder inlet pressure, P B is the hydraulic cylinder return pressure, M is the equivalent mass of the actuator, and F is the load force.

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

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

[0082] The flow solver has the following characteristics: the pressure loss Δp x at the current actuator action of the hydraulic support actuator, the pipeline pressure transmission time Δt x at the current actuator action, the emulsion pump station outlet pressure, the number of current action actuators, the cylinder diameter, the rod diameter and other basic parameters are input; the flow value meeting the outlet pressure control target of the liquid supply system in a future period of time and the lead liquid supply time (Δt x ) under the current actuator action are output and input into the flow regulating actuator.

[0083] The flow regulating actuator takes the flow value meeting the outlet pressure control target of the liquid supply system in a future period of time and the lead liquid supply time (i.e. Δt x ) under the current actuator action as input, and takes the parallel pump control / flow valve bypass lead regulation flow value as output.

[0084] As shown in Figure 2 and Figure 3 , the present application discloses a hydraulic support liquid supply system model predictive control stable pressure liquid supply method, comprising the following steps:

[0085] The hydraulic support pushing conveyor, lowering frame, moving frame and lifting frame are a working cycle, so the flow and pressure of the system exist weak periodic characteristics during the working process of the hydraulic support. Therefore, a database of system parameters during the execution of the hydraulic support is established, and the outlet pressure of the pump station of the liquid supply system, the end pressure of the hydraulic support, the liquid supply state of the emulsion pump station and the liquid use state of the end of the hydraulic support are recorded during each working cycle,

[0086] According to the switch signal of the electromagnetic reversing valve of the hydraulic support, the current execution action of the hydraulic support is determined. When it is detected that the execution action of the hydraulic support is inconsistent with the type in the database, the current execution action of the hydraulic support is obtained according to the switch signal of the electromagnetic reversing valve of the hydraulic support, and the basic parameters of the liquid supply system of the hydraulic support are obtained. The distance x between the current execution mechanism and the emulsion pump station is calculated, and the load force F of the current hydraulic support is estimated i ;

[0087] The model of the liquid supply system of the hydraulic support corresponding to the execution mechanism action state is determined, so as to output the outlet pressure (pipeline inlet pressure) of the emulsion pump station, the end pressure (pipeline outlet pressure) of the hydraulic support, the liquid supply state (unloading valve switch signal) of the emulsion pump station and the liquid use state (electromagnetic reversing valve switch signal) of the end of the hydraulic support.

[0088] The above obtained 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); the pipeline pressure transmission time Δt at any position x away from the emulsion pump station x =x / v x , v x =f(x, v);

[0089] The distance x between the current execution mechanism and the emulsion pump station is input to obtain the pressure loss Δp at the current execution action of the hydraulic support x and the pipeline pressure transmission time Δt at the current execution action of the hydraulic support x ;

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

[0091] The flow value meeting the outlet pressure control target of the liquid supply system in a future period of time and the advance liquid supply time (i.e. Δt x) as the flow regulating actuator input, the parallel pump control / flow valve bypass advanced regulation flow value is obtained;

[0092] When the hydraulic support execution action is detected to be consistent with the type in the database, according to the hydraulic support electromagnetic reversing valve switch signal, the corresponding emulsion pump station outlet pressure, hydraulic support end pressure, emulsion pump station liquid supply state, hydraulic support end liquid state data are called;

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

[0094] According to the current hydraulic support load force estimation method, the current hydraulic support load force (F i+1 ) in the long-distance liquid supply pipeline model input is obtained;

[0095] The x+s and F i+1 in the current state are input into the long-distance liquid supply pipeline model, the pipeline pressure p x+s at any position x+s from the emulsion pump station under the current action state is obtained, the pipeline pressure transmission time Δt x+s at any position x+s from the emulsion pump station is x+s / v x , v x+s =f( x+s , v); the pipeline pressure transmission time (Δt x+s ) corresponding to the distance (x+s) between the current execution mechanism and the emulsion pump station and the pressure loss (Δp x+s ) at the current hydraulic support execution action are obtained, and the output is updated by the flow solver;

[0096] According to the flow value meeting the liquid supply system outlet pressure control target in the future period of time updated by the flow solver and the advanced liquid supply time (namely Δt x+s ) under the current execution mechanism action, the corresponding parallel pump control / flow valve bypass advanced regulation flow value is obtained by inputting the flow regulating actuator;

[0097] The above embodiments are only for illustrating the technical concept and characteristics of the present application, the purpose is to enable those skilled in the art to understand the content of the present application and to implement it, and cannot limit the protection scope of the present application. Any equivalent changes or modifications made according to the essence of the present application shall be covered within the protection scope of the present application.

Claims

1. A hydraulic support liquid supply system model predictive control constant pressure liquid supply method, characterized in that, The steps are as follows: Obtain the number of all hydraulic supports in the entire hydraulic support liquid 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 liquid supply system model is constructed according to the hydraulic support liquid supply system, which includes a large-inertia emulsion pump model for digitally simulating an emulsion pump station, an accumulator model, and an unloading valve model, a long-distance liquid supply pipeline model for digitally simulating a long-distance liquid supply pipeline, a hydraulic support electromagnetic reversing valve group model for digitally simulating a hydraulic support, and a hydraulic support emulsion oil cylinder model; the large-inertia emulsion pump model is connected with the long-distance liquid supply pipeline model through the accumulator model and the unloading valve model, and the long-distance liquid supply pipeline model is connected with the hydraulic support electromagnetic reversing valve group model and the hydraulic support emulsion oil cylinder model; the hydraulic support liquid supply system model can derive the current hydraulic support execution action information by reading the electromagnetic reversing valve switch signals on all hydraulic supports in the hydraulic support liquid supply system; A flow solver for calculating the flow value meeting the outlet pressure control target of the liquid supply system and the current hydraulic support action lead time is constructed; The distance x between the current hydraulic support and the emulsion pump station is calculated by the distance between the current executing action hydraulic support and the emulsion pump station; the current hydraulic support load force F is obtained by the hydraulic support load force estimation method i ; according to the obtained hydraulic support liquid supply system basic parameters, the current hydraulic support and the emulsion pump station distance x and the current hydraulic support load force F i The hydraulic support liquid supply system model is inputted, so that the hydraulic support liquid supply system model outputs the system parameter information in the corresponding hydraulic support action state: the emulsion pump station outlet pressure or pipeline inlet pressure, the hydraulic support end pressure or pipeline outlet pressure, the emulsion pump station liquid supply state or unloading valve state, the hydraulic support end liquid state or hydraulic support electromagnetic reversing valve switch signal; The output of the hydraulic support liquid supply system model is input into the long-distance liquid supply pipeline model to obtain the pipeline pressure p at any position x of the long-distance emulsion pump station under the current action state x = f(x, p0); the pipeline pressure transmission time Δt at any position x of the long-distance emulsion pump station is x / v x x = f(x, v); v x is the average flow rate of the fluid in the pipeline, and v is the outlet flow rate of the emulsion pump station;​ Put the distance x between the current hydraulic support and the emulsion pump station into p x = f(x, p0) and Δt = x / v x , v x = f(x, v), to get the pressure loss Δp at the current hydraulic support execution action x and the pipeline pressure transmission time Δt at the current hydraulic support execution action x ; Loss of pressure Δp at the current hydraulic support executing action x , pipeline pressure transmission time Δt at the current hydraulic support executing action x , emulsion pump station outlet pressure, current action hydraulic support basic parameter input flow solver, get the flow value that satisfies emulsion pump station outlet pressure control target when hydraulic support executes next action, and the leading liquid supply time Δt under the current hydraulic support action a ; The predicted flow value and the lead liquid supply time Δt a The input flow regulating actuator obtains the parallel pump control or flow valve bypass lead regulating flow value, and adopts the parallel pump control or flow valve bypass lead regulating flow value to regulate the flow in advance; The pressure at any point in the pipeline is calculated using the long-distance liquid supply pipeline model: The pressure in the pipeline at any position x from the emulsion pump station in the whole working face is p x =f(x, p0), wherein x is the distance of a certain point on the pipeline from the emulsion pump station, and p0 is the outlet pressure of the emulsion pump station; Throughout the working face, the pressure loss Δp at any position x 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 face is: Δt x = x / v x , v x = f(x, v), where v x is the average flow velocity of the fluid in the pipeline, v is the flow velocity at the outlet of the emulsion pump station; Throughout the working face, the pipeline pressure transmission time Δt at any position x from the emulsion pump station x = x / v x , and Δp x , Δt x as the input of the flow solver model.

2. The hydraulic support liquid supply system model predictive control constant pressure liquid supply method according to claim 1, characterized in that: The specific steps are as follows: A working cycle of a hydraulic support in the working face includes pushing the conveyor, lowering the support, pulling the support, raising the support, and supporting the wall, so there is a weak periodic characteristic of the flow and pressure of the hydraulic support liquid supply system during the working process of the hydraulic support. A hydraulic support execution action process hydraulic support liquid supply system parameter database is established to record the emulsion pump station outlet pressure, hydraulic support emulsion oil cylinder end pressure, emulsion pump station liquid supply state, and hydraulic support emulsion oil cylinder end liquid state data during each hydraulic support working cycle in the working face. The execution action of the hydraulic support is determined by the electromagnetic reversing valve switch signal 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 hydraulic support liquid supply system parameter database, the basic parameters of the hydraulic support liquid supply system are obtained according to the current electromagnetic reversing valve switch signal of the hydraulic support, the execution action of the current action hydraulic support is obtained, the distance x between the current hydraulic support and the emulsion pump station is calculated, and the load force F of the current hydraulic support is estimated i ; The basic parameters of the hydraulic support liquid supply system and the distance x between the hydraulic support and the emulsion pump station, the load force F of the hydraulic support i The hydraulic support liquid supply system model is input, and the emulsion pump station outlet pressure, the hydraulic support end pressure, the emulsion pump station liquid supply state, and the hydraulic support electromagnetic reversing valve switch signal are output after simulation by the hydraulic support liquid supply system model. Using long distance liquid supply pipeline model, according to the distance x between hydraulic support and emulsion pump station, current hydraulic support load force F i , the pipeline pressure p at any position x from emulsion pump station is calculated x =f(x, p0); the pipeline pressure transmission time Δt at any position x from 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, and obtain the pressure loss Δp at the current hydraulic support execution action x The pipeline pressure transmission time Δt at the current hydraulic support execution action x ; Loss of pressure Δp at the current hydraulic support executing action x , pipeline pressure transmission time Δt at the current hydraulic support executing action x , emulsion pump station outlet pressure, current action hydraulic support basic parameter input flow solver, get the flow value that satisfies emulsion pump station outlet pressure control target when hydraulic support executes next action, and the leading liquid supply time Δt under the current hydraulic support action a ; The flow value satisfying the hydraulic support to execute the next action is compared with the advance liquid supply time Δt under the current hydraulic support action a An input flow regulation executor is used to control the parallel pump control or flow valve bypass advance to perform flow regulation. When the current execution action of the hydraulic support is detected to be consistent with the action type recorded in the hydraulic support liquid supply system parameter database, the corresponding emulsion pump station outlet pressure, hydraulic support end pressure, emulsion pump station liquid supply state, and hydraulic support end liquid state data are called according to the electromagnetic reversing valve switch signal of the hydraulic support. According to the current hydraulic support and emulsion pump station distance calculation method, the current hydraulic support and emulsion pump station distance x 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 ; x and F in the current state i Input long-distance supply pipeline model, get the current action state of the distance emulsion pump station at any position x in the pipeline pressure p x = f(x, p0); distance emulsion pump station at any position x in the pipeline pressure transfer time Δt x = x / v x , v x = f(x, v); distance x between the current hydraulic support and the emulsion pump station corresponding to the pipeline pressure transfer time Δt x And the pressure loss Δp at the current hydraulic support action x , into the flow solver to update the output; The flow value meeting the outlet pressure control target of the liquid supply system in the future period updated by the flow solver and the lead liquid supply time Δt under the current hydraulic support action a The flow regulating actuator is input, and the flow regulating actuator is controlled to lead the flow regulation in parallel with the pump control or the flow valve bypass.

3. The hydraulic support liquid supply system model predictive control constant pressure liquid supply method according to claim 1, characterized by, The flow regulation executor working process is as follows: the maximum liquid supply flow of the emulsion pump station is quickly increased by parallel liquid supplementing of the liquid supplementing pump, and the liquid supply flow of the emulsion pump station is reduced by bypass throttling of the flow valve; the flow value obtained by the flow solver and the pressure transmission time of the long-distance liquid supply pipeline are used to perform flow regulation in advance: the output flow of the emulsion pump station is increased or decreased in advance to compensate for the lag caused by pressure transmission.

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

5. The hydraulic support liquid supply system model predictive control constant pressure liquid supply method according to claim 1, characterized by, The current method for estimating the load force of hydraulic supports is as follows: Based on the current action type of the hydraulic support, when the load force F is first applied to a certain action during the periodic action of the hydraulic support... i During estimation, the stress conditions and corresponding action process characteristics of the hydraulic support's execution actions are analyzed. Based on the current type of hydraulic support action, the frictional resistance between the support and the working face roof, coal face, and ground is analyzed. Based on the stress analysis, the load force F of the current hydraulic support is estimated. i Estimate the load force F applied to a certain action not for the first time. i During estimation, the Coulomb stress model is used to calculate the load borne by the support, at which point F... i =C*P avg *A, where C is the empirical coefficient, P avg Let A be the average outlet pressure of the emulsion pump station, and let A be the effective area of ​​the emulsion cylinder on the hydraulic support.

6. The hydraulic support liquid supply system model predictive control constant pressure liquid supply method according to claim 1, characterized by, The hydraulic support liquid supply system model predictive control pressure stabilizing liquid supply method has a parameter updating feature; according to the model updating cycle division of different hydraulic support action times, the total time of one-time push conveying, lowering, moving, raising and support action of the hydraulic support is taken as the updating cycle of the model, and the measured pressure of the liquid supply system in each cycle action process is recorded; when the model is updated, the predicted hydraulic support emulsion pump station outlet pressure is obtained according to the hydraulic support electromagnetic reversing valve switch signal, and the corresponding pressure segment in the measured cycle pressure data of the hydraulic support liquid supply system of the fully mechanized coal mining face is compared, the mean pressure change rate parameter in the hydraulic support liquid supply system model and the flow solver is adjusted and optimized according to the pressure difference, and the accuracy of the hydraulic support liquid supply system model for pressure prediction is improved.

7. The hydraulic support liquid supply system model predictive control constant pressure liquid supply method according to claim 1, characterized in that: The emulsion flow in the pipeline in the whole hydraulic support liquid supply system model needs to consider the friction term correction, and the power evolution conforms to the high-pressure and large-flow turbulent unsteady 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 emulsion pump station outlet flow rate, a is the pressure wave velocity, k3 is the Brunone friction coefficient, f is the pipeline internal friction coefficient, θ is the pipeline angle with the horizontal line, and D is the pipeline diameter; The high-pressure and large-flow turbulent unsteady flow pipeline equation is used to consider the influence of the pipeline internal turbulence state and strong time-varying load on the characteristics of the long pipeline, and the friction term correction of the emulsion in the pipeline is considered.

8. The hydraulic support liquid supply system model predictive control constant pressure liquid supply method according to claim 1, characterized in that, The flow required by the hydraulic support actuator action includes three parts: the accumulator liquid supply flow in the whole hydraulic support execution action process, the accumulator is an element in the emulsion pump station, which can adjust its output flow according to the pressure of the hydraulic support liquid supply system, and can absorb the impact in the hydraulic support liquid supply system; The flow caused by the emulsion compression in the whole hydraulic support execution action process; The flow caused by the emulsion cylinder action and load influence in the whole hydraulic support execution action process, which is the flow required for the smooth movement of the actuator; The calculation method of the flow generated by the accumulator in the hydraulic support execution process by using the flow solver is as follows: where P u is the unloading valve unloading pressure, P d is the unloading valve recovery pressure, P0 is the accumulator initial pressure, V0 is the accumulator initial volume, Paˊ is the accumulator liquid supply stage pressure curve change rate, ΔV g is the pipeline volume change during this process, and βe is the emulsion elastic bulk modulus; The calculation formula of the flow caused by the emulsion compression is as follows: Wherein, P in is the outlet pressure of the emulsion pump station, Δp x is the dynamic pressure loss from the emulsion pump station outlet to the hydraulic support emulsion oil cylinder end, V is the pipeline volume from the emulsion pump station outlet to the hydraulic support emulsion oil cylinder end, β e is the emulsion elastic bulk modulus; The calculation formula of the flow caused by the emulsion cylinder action and load influence is as follows: where A A is the area of the hydraulic cylinder inlet side, A B is the area of the hydraulic cylinder return side, P A is the pressure of the hydraulic cylinder inlet side, P B is the pressure of the hydraulic cylinder return side, M is the equivalent mass of the actuator, and F is the load force. The flow value q required by the hydraulic support actuator action output by the flow solver is the sum of the flow generated by the accumulator in the hydraulic support execution process, the flow caused by the emulsion compression and the flow caused by the emulsion cylinder action and load influence, and the flow calculation formula of the flow solver is as follows: q = q x + q c + q d .

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