Compressor control system and compressor control method

Abstract

To perform an optimal control of an air compressor by measuring a response of the pressure to each of the flow rates of a plurality of terminals and by establishing a machine learning model for estimating a variation in terminal pressure.SOLUTION: In a compressor control method in an air pressure system having a plurality of terminals consuming compressed air, a control part of a system 400: a) measures a supply-side pressure by pressure meters 305-307 on an ejection side for supplying the compressed air; b) obtains a pressure value and a flow rate value at the time of opening and closing of the valve by using a pressure meter 113, 123, 243, a flow meter 112, 122, 242, and a valve 111, 121, 241 provided at a part of a terminal of the pipe 11, 12, 24; and leans a terminal-side prediction model of pressure per terminal 11, 12, 24 using a supply pressure value from an air compressor 2-4 and a pressure value and flow rate value on a demand side. During an operation of an air pressure system, an optimal election pressure of the air compressor is calculated by inputting a supply pressure value and an air flow rate value of the terminal to a terminal pressure prediction model by the control part.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a compressor control system and a control method for a facility that has an air compressor controlled by a variable speed device and supplies compressed air to compressed air-using equipment connected to the end via multiple pipes, and in particular to a compressor control system and a control method for the same that efficiently controls the compressor taking into account fluctuations in the amount of compressed air used in the facility. [Background technology]

[0002] Pneumatic equipment that supplies compressed air to various parts of equipment in a factory, etc., temporarily stores compressed air compressed by one or more air compressors in a receiver tank (air tank), and supplies it from this receiver tank to equipment that uses compressed air in the factory's production process, such as air cylinders and air blowers, via piping systems and pneumatic equipment (filters, dryers, control valves, etc.). In the air piping from the air compressor's discharge port to the end, the closer you get to the end, the greater the pressure loss, but the pressure loss also changes depending on the amount of air discharged by the air compressor and the amount of air used at the end. Also, while there are cases where each end of a piping network is as few as a few locations, in large factories there may be tens to hundreds of locations, so the pressure loss constantly changes depending on the fluctuation in the use of discharged air at each end.

[0003] In order to keep the pressure of compressed air supplied to many terminals at a specified pressure or higher, conventional pneumatic equipment has set the discharge pressure of the air compressor to a high value in anticipation of maximum pressure loss. However, the amount of air used at the terminal often varies depending on the type of compressed air-using equipment and the operating rate, and the amount of air used and the pressure fluctuation at that time often differ from day to day. Normally, when the amount of air used is small, the pressure loss is small, and the pressure at the terminal becomes unnecessarily high, resulting in waste in the operation of the air compressor. In particular, if the discharge pressure of the air compressor is constant, the discharge pressure becomes higher than necessary when the amount of air used is small, resulting in excess electricity consumption.

[0004] In the conventional technology, in order to stabilize the discharge pressure of compressed air while obtaining an energy saving effect, constant terminal pressure control is performed according to the fluctuation of the amount of air used at the terminal. That is, this is a method of changing the discharge pressure of the air compressor so that the supply pressure to the terminal is constant. To realize this control, it is necessary to monitor the pressure of the terminal to be controlled and to understand the transmission delay of the pressure from the discharge port of the compressor to the terminal. A general method is to install a pressure gauge at the terminal and to construct a physical model of the air piping (a simulator using differential fluid calculation) to calculate the terminal pressure. However, in a large-scale facility where the terminal pressure to be predicted ranges from tens to hundreds of locations, the number of pressure gauges to be installed becomes enormous, or the piping diagram required for constructing the physical model does not remain, and the labor required for checking and measuring the piping becomes large, so that it may be difficult to use it for control during actual operation in large-scale pneumatic facilities such as factories.

[0005] One approach to reduce the number of pressure gauges to be installed and to understand the terminal pressure and transmission delay without using a piping diagram is to model the characteristics of air piping from data.As a related technique, Patent Document 1 proposes a method for detecting faults in a piping network using a sensor that determines the physical parameters of the gas. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Special Publication No. 2022-517504 Summary of the Invention [Problem to be solved by the invention]

[0007] In the technology of Patent Document 1, an adjustable throttle valve is opened and closed in a predefined sequence in a piping network, and measurements are taken with two groups of pressure gauges (and flow meters, if necessary) during the opening and closing, and a mathematical model is constructed to identify and quantify partial or total blockages in each piping network or increases in resistance within each pipe from the difference in measurements between the first and second groups. Although this model represents the characteristics of an air piping network, it does not have the function to directly calculate the end pressure or the transmission delay from the discharge port to the end, making it difficult to use it for controlling a compressor based on the end pressure.

[0008] An object of the present invention is to realize a compressor control system and method in which pressure gauges and flow meters are provided at multiple terminals and a machine learning model that predicts terminal pressure from flow rate is constructed in advance by measuring the pressure response to each flow rate. Another object of the present invention is to realize a compressor control system and method that zones the piping network during actual operation of pneumatic equipment, predicts the end pressure by inputting air flow values ​​at a representative end or all ends of each zone into a machine learning model, and optimally controls the discharge pressure of the air compressor based on the predicted value. Yet another object of the present invention is to realize a compressor control system that enables a user who sets the number of operating air compressors and the discharge pressure to simulate the discharge pressure of an air compressor and the terminal pressure of a zoned zone using the constructed machine learning model. [Means for solving the problem]

[0009] Representative features of the invention disclosed in this application are as follows. According to one feature of the present invention, a compressor control system controls equipment that supplies compressed air discharged from an air compressor to multiple terminals that consume the compressed air through multiple pipes, and a pressure gauge is provided at one or multiple supply points near the air compressor or a receiver tank, a pressure gauge, a flow meter, and a valve are connected to all or part of the terminals of the pipes, and the terminals are opened while changing the opening degree of the valve, and data on the pressure and flow rate measured at that time is stored in a storage means. Using these measured data, a terminal pressure prediction model that inputs the pressure at the supply point and the flow rates at multiple terminals and outputs the terminal pressure is learned by a terminal pressure prediction model construction unit. When the equipment is actually operating, the measured value of the pressure at the supply point and the flow rate information for each terminal during the actual operation of the equipment are input to the learned terminal pressure prediction model, and the terminal pressure is predicted by the terminal pressure prediction unit, and the set pressure search unit searches for and sets the optimal discharge pressure of the air compressor using the predicted terminal pressure value. One or more air compressors are provided, and the operation unit controls the rotation speed of the air compressors and the number of operating air compressors so that the multiple terminal pressures set by the set pressure searching unit fall within a specified range.

[0010] According to another feature of the present invention, the terminal pressure prediction unit is used to control the rotation speed and the number of operating air compressors so that the future predicted values ​​of the pressures at multiple terminals and the discharge pressure of the air compressor are constant. A terminal pressure prediction model is used when calculating this predicted value, and the terminal pressure prediction model construction unit uses many terminal pressure measurement values ​​and flow rate information during model learning to set the optimal discharge pressure. During actual operation, the terminal pressure is predicted using only a smaller number of terminal flow rate information than during learning. Furthermore, multiple terminal parts branching off from multiple pipes (pipe groups) are defined as zones, and a representative terminal for measuring the flow rate is set for each zone. The terminal pressure prediction unit sets the optimal discharge pressure of the air compressor using only actual measurement data of representative terminal flow rates. As a result, when the equipment is in operation, the air compressor can be controlled by using the terminal pressure prediction model with flow rate measurement data from a small number of terminals as input.

[0011] According to yet another feature of the present invention, an input / output unit is provided for inputting and outputting (displaying) information, and a user inputs the rated flow rate, operation method, and operation rate of the equipment connected to the terminal, which are stored in advance in a storage device as a model database. The terminal pressure prediction unit estimates the change pattern of the terminal flow rate from the change pattern of the input information and the measured value of the supply point pressure, and predicts the measured value of the supply point pressure and the future pressure change pattern. In addition, a display device is provided for visually displaying information to the user, and the optimal discharge pressure of the air compressor set by the set pressure search unit is displayed on the display device, allowing the user to monitor the operating status of the equipment. In addition, in the compressor control system of the present invention, the set pressure search unit simulates the optimal discharge pressure of the air compressor in response to the input of the terminal target pressure by the user, and makes it possible to display it on the display device.

[0012] According to still another feature of the present invention, there is provided a compressor control method for a pneumatic system in which compressed air discharged from an air compressor is supplied to a plurality of terminals consuming the compressed air through a plurality of pipes, using a control unit having a processor, and a terminal pressure predictive control system having an input / output device and a storage device connected to the control unit, the control unit comprising: a) measuring the supply side pressure using a single or multiple pressure gauges installed on the discharge side that supplies compressed air to multiple pipes; b) Obtain pressure and flow values ​​when the valve is open or closed using a pressure gauge, flow meter, and valve installed at all or part of the end of the piping; c) A terminal pressure prediction model is trained using the supply pressure value from the air compressor and the demand side pressure value and flow rate value, and the terminal pressure is output. When the pneumatic system is in operation, the control unit: d) Connect a compressed air device to the end instead of the valve; e) The optimum discharge pressure of the air compressor is calculated by inputting the supply pressure value and the terminal flow rate value into the terminal pressure prediction model. Effect of the Invention

[0013] According to the present invention, it is possible to monitor and predict the pressure margins at multiple ends according to the usage status of compressed air, and by controlling the air compressor so that the pressure at the end with the smallest pressure margin is equal to or higher than the lower limit, it is possible to reduce the discharge pressure on the air compressor side as much as possible. As a result, it is possible to realize a compressor control system that contributes to energy saving and is environmentally friendly. In addition, it is possible to effectively suppress hunting caused by a delay in the fluctuation of the discharge pressure of the air compressor to the end pressure. Problems, configurations and effects other than those described above will become apparent from the following description of the embodiments. [Brief description of the drawings]

[0014] [Figure 1] FIG. 1 is a schematic configuration diagram of a pneumatic facility to which an embodiment of the present invention is applied, showing an example of a piping network for sending out compressed air from an air compressor 2. [Diagram 2] 1 is a configuration diagram of a compressor control system 1 according to an embodiment of the present invention. [Diagram 3] 3 is a flowchart showing a procedure for measuring the pressure and flow rate at each end of FIG. 2. [Figure 4] 5 is a flowchart showing a model construction procedure for terminal pressure predictive control according to the present embodiment. [Diagram 5] 5 is an example of a display screen during model construction in steps 511 to 512 of FIG. [Figure 6] FIG. 11 is a system configuration diagram for operating actual equipment using a terminal pressure prediction model when measuring all terminals in this embodiment. [Figure 7] 7 is a diagram showing an example of an input / output screen 470 in the input / output unit 410 of FIG. [Figure 8] FIG. 3 is a diagram showing an example of a method for estimating an optimal pressure taking multiple terminals into consideration in the terminal pressure predictive control system 400 of FIG. 2. [Figure 9] 3 is a diagram showing an example of control for suppressing hunting caused by a delay in the fluctuation of the terminal pressure in the terminal pressure prediction control system 400 of FIG. 2. FIG. [Figure 10] 3 is a flowchart of compressor control in the terminal pressure predictive control system 400 of FIG. 2. [Figure 11] 11 is a subroutine showing a procedure for searching for an optimum value of the discharge pressure in step 523 of FIG. 10. [Figure 12] FIG. 11 is a configuration diagram showing a model operation configuration during zoning in a terminal pressure predictive control system 400 according to a second embodiment of the present invention. [Figure 13] 13 is an example of a definition table when the ends of the control targets in FIG. 12 are assigned to each zone. [Figure 14] FIG. 11 is a schematic configuration diagram of a pneumatic facility modeled at the time of zoning in a terminal pressure predictive control system 400 according to a modified example of the second embodiment of the present invention. [Figure 15] FIG. 13 is a diagram showing a model for predicting end pressure including unmeasured ends using learned model parameters. [Figure 16] 4 is a table showing measurement points and operating characteristics in three usage patterns of the compressor control system according to the present invention. [Figure 17] FIG. 11 is a configuration diagram of a compressor setting pressure recommendation system 400A according to a third embodiment of the present invention when recommending compressor settings. [Figure 18] 13 is a display screen when recommending compressor setting in a compressor setting pressure recommendation system 400A according to a third embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the following drawings, the same parts are given the same reference numerals and the repeated description will be omitted.

[0016] FIG 1 is a schematic diagram of a pneumatic facility to which an embodiment of the present invention is applied, showing a portion of a piping network for sending out compressed air from an air compressor 2. Here, compressed air is supplied from the supply side facility to the left of the dashed line to terminals 11-14, 21-24 via multiple parent pipes 300, 10, 20. The supply side facility is provided with one or more air compressors 2, and compressed air is sent through a supply side parent pipe 300 to a branch point 310. A pressure gauge 305 is provided in the parent pipe 300, and the discharge pressure P comp is measured. The piping structure downstream of branch point 310 (the side farther from the air compressor as viewed from the air flow) differs depending on the factory and type of pneumatic equipment. In addition, since the amount of compressed air used in pneumatic equipment varies, the number of air compressors used in the supply-side equipment may be not only one but multiple. When multiple air compressors are used, a receiver tank (not shown) may be provided upstream of branch point 310 (the supply-side equipment closer to air compressor 2).

[0017] A main pipe 10 having a straight pipe shape with a dead end at the end is provided downstream of the branch point 310, and a plurality of thin branch pipes (not shown) are provided that further branch from the main pipe 10, and the ends of the branch pipes are the ends 11 to 14. Hereinafter, the ends of the branch pipes are referred to as "ends" in this specification. Although not shown here, devices using high-pressure air are provided downstream of the ends 11 to 14. Valves 111, 121, 131, and 141 that open or close the air flow are provided downstream of the ends 11 to 14. Note that the valves 111, 121, 131, and 141 are not necessarily provided, and the valves 111, 121, 131, and 141 may be omitted and the ends 11 to 14 may be directly connected to the devices using high-pressure air, or a coupler may be used to enable connection and disconnection. Here, the main pipe 10 and the ends 11 to 14 are defined by the user as "zone 1". The portion of piping 11 enclosed by the dashed line was selected by the user as a representative piping that closely reflects pressure fluctuations in zone 1, and is managed as "end #11."

[0018] The main pipe 20 is a pipe that branches off from a branch point 310 and is then formed into a loop. Terminals 21-24 are provided that further branch off from the main pipe 20. Here, the main pipe 20 and the terminals 21-24 are defined by the user as zone 2. Note that any number of terminals can be provided to the main pipes 10 and 20, and the number of terminals is not limited to four as shown in the figure. Equipment (not shown) that uses high-pressure air and valves 211, 221, 231, and 241 that open or close the air flow are provided downstream of the terminals 21-24. The portion of the pipe 21 surrounded by the dashed line is selected by the user as a representative pipe that reflects pressure fluctuations in zone 2, and is managed by this system as "terminal #21". A flowmeter 212 and a pressure gauge 213 are provided in the terminal 21.

[0019] The parent pipes 10, 20 from branch 310 of parent pipe 300 onwards and each of the terminals connected to them are regarded as one "zone", and a hypothesis is made that within the same zone, pressure fluctuation characteristics (time response of pressure to changes in the amount of air used) are roughly the same. One terminal (11, 21) is defined as a representative point for each zone, and this terminal is always used as the measurement point when creating the machine learning model. When creating the machine learning model, pressure gauges 113, 213 and flow meters 112, 212 are installed at the representative points, and the flow rate and pressure are measured while changing the opening of valves 111, 211. Through this operation, the terminal pressure p is made to correspond to the terminal number, and the pressure p of terminals 11 and 21 is calculated. 1 , p 2 , terminal flow rate u 1 , u 2is measured and recorded in the storage device of the system. In this way, the basic idea of ​​the present embodiment 1 and 2 is to learn the pressure fluctuation characteristics of each zone from the measurement data of the representative terminals 11 and 21, and to monitor and control the pressure of each terminal including the future value using the pressure fluctuation characteristics and the flow rate information for each of a plurality of terminals including the representative terminals 11 and 21. The number of representative terminals is arbitrary, and one or more terminals may be set for each zone (embodiment 2), or a machine learning model for terminal pressure predictive control may be constructed by measuring the pressure and flow rate of all or almost all terminals without setting a representative terminal (embodiment 1). When a machine learning model for terminal pressure predictive control (terminal pressure predictive model) is constructed, optimal operation control of the air compressor is performed using the constructed terminal pressure predictive model when the actual pneumatic system is in operation. EXAMPLES

[0020] 2 is a configuration diagram of a compressor control system 1 according to a first embodiment of the present invention. In the compressor control system 1, a pneumatic facility having one or more air compressors 2-4 and a piping network 8 from the air compressors 2-4 to a supply destination device (not shown) is treated as a control object, and a plurality of measurement data (piping pressure, piping flow rate) is acquired from the control object, collected by a terminal pressure prediction control system 400, and processed.

[0021] The left side of Fig. 2 illustrates the pneumatic equipment shown in Fig. 1 arranged so that the flow of air sent from the supply source (air compressors 2, 3, ..., 4) to supply equipment (not shown) connected to the end of valves 111, 121, ..., 241 runs from top to bottom. The piping network 8 includes the supply-side mother pipe 300 shown in Fig. 1 and multiple mother pipes 10, 20, etc. connected to the supply-side mother pipe 300, and also includes a receiver tank (not shown) for mitigating fluctuations in discharge pressure to the multiple mother pipes. The supply-side equipment includes multiple air compressors 2, 3, ..., 4. The number and type of air compressors are arbitrary as long as they can stably supply the required amount of compressed air to the supply destination (equipment using high-pressure air) (not shown).

[0022] A plurality of pipes 11, 12, ..., 24 branch out from the piping network 8. These pipes 11, 12, ..., 24 correspond to the terminals 11, 12, ..., 24 shown in Fig. 1, respectively. For convenience of explanation, Fig. 2 illustrates the piping network 8 and the terminals 11, 12, ..., 24 separately, but in a broad sense, the terminals 11, 12, ..., 24 are also part of the piping network 8. Each of the air compressors 2, 3, ..., 4 is connected to the piping network 8 by individual pipes 302, 303, ..., 304. The pipes 301, 302, ..., 304 are provided with pressure gauges 305, 306, ..., 307, respectively, and their outputs are transmitted to the terminal pressure prediction control system 400 in real time. As explained in the legend at the bottom left of the figure, the dashed arrows extending from the control devices and meters indicate "data flow" via signal lines or wireless communication, and the solid arrows extending from users 80, 480 indicate input instructions by "user operation." The equipment on the left side of Fig. 2 controls a wide variety of devices other than the compressors 2 to 4 and is formed as an "air pressure system."

[0023] In this embodiment, the actual characteristics of the pneumatic system are measured in advance to construct (machine learning) a terminal pressure prediction model to be used during actual operation. In an actual pneumatic system such as a factory or facility, pressure gauges (112, 123, ..., 244), flow meters (112, 122, ..., 242), and valves (111, 121, 241) are installed at all ends (ends of pipes 11, 12, ..., 24). Note that installing flow meters at all ends does not mean strictly installing measuring instruments at 100% of the ends, and measurements at small pipe ends that do not affect pressure fluctuations or pipe ends that are physically difficult to measure may be omitted. These operations are performed in advance by a user 380 before constructing a terminal pressure prediction model. The user 380 is, for example, a serviceman of a manufacturer that provides the terminal pressure prediction control system 400. The portion where the valves (111, 121, 241) are provided is usually connected to a high-pressure air-using device (not shown) to which the compressed air is supplied, and the compressed air is used to perform a predetermined operation, work, control, etc. However, when making measurements to create a model, the terminal is disconnected from the high-pressure air-using device, and the downstream side of the valves (111, 121, 241) is opened to the atmosphere or closed. Then, a user 380 measures the changes in pressure and flow rate while opening and closing each valve at each terminal, and records the measured data in an experiment DB (database) 420 of the terminal pressure prediction control system 400.

[0024] The terminal pressure prediction control system 400 includes a processing device (processor) such as a CPU (Central Processing Unit), a DSP (Digital Signal Processor), a GPU (Graphics Processing Unit), or an FPGA (Field-Programmable Gate Array), a storage device (memory) such as a ROM (Read Only Memory), a RAM (Random Access Memory), a HDD (Hard Disk Drive), or an SSD (Solid State Drive), an input / output unit that inputs information from a user and displays information to the user, and a network interface, and is configured so that a computer program previously stored in the storage device can be executed by the processor. This device can be realized, for example, by a personal computer, a portable terminal device, or a server device. The terminal pressure prediction control system 400 may also be configured to be incorporated in a control panel (not shown) for controlling the number of air compressors.

[0025] The processor (not shown) of the terminal pressure prediction control system 400 executes a specific computer program to execute the machine learning function of the terminal pressure prediction model construction unit 401 to generate a terminal pressure prediction model 430, and further executes the prediction function of the terminal pressure prediction unit 402 based on the model. The input / output unit 410 has an output function to visually display various information to the user 80, and an input function to accept input instructions from the user 80. The input / output unit 410 can be configured with a dot-matrix display device and an input device such as a keyboard or a mouse, but it is also possible to configure the input device and the output device simultaneously using a touch-type liquid crystal display panel. The detailed configuration of the input / output unit 410 is arbitrary, and it is also possible to use an operation terminal, a mobile terminal, a smartphone, etc. at a remote location as an input / output device. The experiment DB (database) 420 is constructed in a non-volatile storage device such as an HDD or SSD, and records measurement data acquired from each pressure gauge and each flow meter when the user 380 operates the valves 111, 121, ..., 241 in various ways, together with the acquisition time. The model DB (database) 430 stores data of the terminal pressure prediction model constructed as a result of learning by the terminal pressure prediction model construction unit 401, and is stored in a non-volatile storage device such as an HDD or SSD.

[0026] The terminal pressure prediction model construction unit 401 constructs a machine learning model that predicts the fluctuation of the pressure at the terminals 11, 21, ..., 14 using the discharge pressures measured by the pressure gauges 302-305 and the measured values ​​of the pressure and flow rate measured at each terminal 11, 21, ..., 14. The constructed machine learning model is stored in a model database (DB) 430. The terminal pressure prediction unit 402 inputs the measured flow rate value and the measured discharge pressure value measured at each terminal into the terminal pressure prediction model during operation of the pneumatic system to predict the pressure at the terminals 11, 21, ..., 14. The set pressure search unit 403 searches for the set pressure of the air compressors 2-4 that approaches the target pressure of each terminal set by the user 80 based on the predicted value predicted by the terminal pressure prediction unit 402. The set pressure set by set pressure searching unit 403 is transmitted to number of operating units / rotation speed operating unit 404, which controls the number of operating units and rotation speed of air compressors 2 to 4 so as to realize the set pressure. Note that terminal pressure prediction unit 402, set pressure searching unit 403, and number of operating units / rotation speed operating unit 404 are realized by a processor (not shown) executing a computer program for realizing the above functions.

[0027] Fig. 3 is a flow chart showing a procedure for measuring the pressure and flow rate at each end of the piping network that is the target of the terminal pressure prediction control in Fig. 2. First, the user 380 disconnects the high-pressure air-using equipment from the ends of the piping 11-14, 21-24, and connects the valves 111, 121, ..., 241, the flowmeters 112, 122, ..., 242, and the pressure gauges 113, 123, ..., 243 (step 501). The downstream side of the valves (111, 121, 241) is opened to the atmosphere. The user 380 who performs this operation may be, for example, a serviceman of the manufacturer of the air compressors 2-4, or a control engineer of the terminal pressure prediction control system 400. Next, the user 380 selects the end of the piping 11-14, 21-24 that is the target of operation (step 502).

[0028] Next, the user 380 sets the opening of the selected terminal valve to 100% and waits for about one minute (step 503). During this time, the outputs of the flowmeters 112, 122, ..., 242, the pressure gauges 113, 123, ..., 243, and the pressure gauges 305, 306, and 307 are electrically transmitted to the terminal pressure predictive control system 400 via signal lines. A processor (not shown) of the terminal pressure predictive control system 400 stores the transmitted outputs in the experiment DB 420. Next, the user 380 sets the valve opening to 50% and waits for about one minute (step 504). During this time, the pressures of the flowmeters 112, 122, ..., 242, the pressure gauges 113, 123, ..., 243, and the outputs of the pressure gauges 305, 306, and 307 are electrically transmitted to the terminal pressure predictive control system 400 via signal lines and stored in the experiment DB 420. The measured data may be temporarily stored in a storage device built into the pressure gauges 113, 123, ..., 243 and the flow meters 112, 122, ..., 242, and the stored data may be copied to a USB memory (USB is a registered trademark of USB Implementers Forum) after the measurement is completed, and then the removed USB memory may be connected to the terminal pressure predictive control system 400 and transferred to the experimental DB (database) 420. Furthermore, the outputs of the pressure gauges 113, 123, ..., 243 and the flow meters 112, 122, ..., 242 may be stored in a personal computer for measurement via a signal line, and the data may be transferred to the terminal pressure predictive control system 400 via wireless communication or a connection via USB (registered trademark) after the measurement is completed to the experimental DB (database) 420.

[0029] Next, the user 380 judges whether there is an unoperated terminal, that is, whether the output by the flowmeter and the pressure meter at the valve opening of 100% and 50% has been stored in the experiment database 420 of the terminal pressure prediction control system 400 (step 505), and if there is an unoperated terminal, the process returns to step 502 and repeats steps 502 to 504. The judgment in step 505 may not only be performed by the user 408, but also by a processor (not shown) of the terminal pressure prediction control system 400 executing a computer program to display a list of terminals to be operated on the screen of the input / output unit 410, sequentially specify the operation of the valve of the terminal to be measured on the screen, and when the measurement of the specified terminal is completed, display the terminal as completed, thereby supporting the user 408 in opening and closing the valve.

[0030] In step 505, when the measurement of pressure data and flow rate data of all the terminals (pipes 11-14, 21-24) to be operated is completed, the data are compiled to construct an experimental database 420, and stored in the storage device of the terminal pressure predictive control system 400 (step 506). As described above, in this embodiment, valves, flow meters, and pressure gauges are basically provided at the ends of all of the pipes 11-14, 22-24 to measure actual values, but the installation may be omitted for small pipes that have little effect on the terminal pressure predictive control system, or for pipes on which it is difficult to install valves, flow meters, or pressure gauges, so it is not necessary to cover all pipes.

[0031] When data measurement for predictive control according to this embodiment is completed and accumulation of measurement values ​​in the experiment database 420 is completed according to the procedure shown in the flowchart of Fig. 3, a processor (not shown) of the terminal pressure predictive control system 400 constructs a terminal pressure predictive model according to the procedure shown in the flowchart of Fig. 4. The procedure shown in Fig. 4 is executed by a terminal pressure predictive model construction unit 401. The terminal pressure predictive model construction unit 401 is realized by software when the processor of the terminal pressure predictive control system 400 executes a learning program for constructing a terminal pressure predictive model stored in advance in a storage device (not shown).

[0032] First, the user 380 operates the input / output unit 410 (e.g., a keyboard or a mouse) to specify parameters and a data range for constructing the model (step 510). Next, the terminal pressure prediction model constructing unit 401 constructs a terminal pressure prediction model from the pressure data and flow rate data in the specified data range (step 512). Specifically, it has a function of inputting the actual measured values ​​of the terminal flow rate and the discharge pressure into the terminal pressure prediction model to predict the terminal pressure. As a basic configuration of the terminal pressure prediction model, a model is considered in which the past history of the discharge pressure and the square of the terminal flow rate are input and the terminal pressure is predicted up to the L (≧1) time point in the future, taking into consideration that the total amount of use of the piping can be estimated from the time rate of change of the discharge pressure and that the pressure loss due to friction in the pipe is proportional to the square of the flow velocity (Darcy-Weisbach equation). This terminal pressure prediction model is shown in Equation 1.

[0033]

number

[0034] The role of each matrix in Equation 2 is to express how much delay there is in transmitting the change in discharge pressure to the end pressure.

[0035]

number

[0036]

number

[0037] The model building algorithm is as follows: (1) Select the number of prediction points L and the number of delay points d. The prediction point L is selected so that LΔt is of the same order as the delay (approximately 10 to 20 seconds if Δt = 1 s). The delay point d is selected so that d>M(L-1) in order to effectively solve the optimization problem in the later stage. (2) Time t 1 ,…,t N From the data of the supply pressure, end pressure, and end flow rate around the time t, the matrix Y of the following equation 4, the matrix X of the following equation 5, and the matrix U of the following equation 6 are constructed. 1 ,…,t N does not have to be consecutive. However, at each time t i For the interval [t i -dΔt,t i +LΔt] data must be measured continuously.

[0038]

number

[0039]

number

[0040]

number

[0041]

number

[0042]

number

[0043] Next, a method for the user 380 to specify a data range will be described with reference to FIG. 5. FIG. 5 is an example of a screen 550 displayed by the input / output unit 410 when constructing a model. The left frame of the screen 550 is an area showing actual measurement data 551 measured in the procedure shown in FIG. 3, and the right frame is an area showing pressure loss confirmation 570 in a data section 564 specified by the user 380 among the actually measured data. A graph 552 showing the measured pressure values ​​of each part is displayed at the top of the frame of the actual measurement data 551. The horizontal axis of the graph 552 is the elapsed time (unit: seconds), and the vertical axis is the pressure value (unit: MPa) at the measurement point by the pressure gauge. A solid line 553 is the combined discharge pressure of air compressors 2 to 4, a dotted line 554 is the pressure value of terminal 1, and dashed lines 555 and 556 are the pressure values ​​of terminals 2 and 3. Here, the first to third ends of zone 1 (e.g., corresponding to ends 11 to 13 in Figure 1) are shown as an example, but since there are many ends as shown in Figure 1, it is advisable for the user to specify the end that he or she wishes to check and display screen 550.

[0044] A graph 560 showing the measured flow rate values ​​at each point is displayed near the center of the frame of the actual measurement data 551. The horizontal axis of the graph 560 is the passage of time (unit: seconds), which is aligned with the horizontal axis of the graph 552. The vertical axis of the graph 560 is the flow rate value (unit: 10 -2ks / s). The dotted line 561 is the flow rate value of the terminal 1, and the dashed lines 562 and 563 are the flow rate values ​​of the terminals 2 and 3. What can be understood here is that when compressed air is consumed at a specific time as shown in the graph 560 at each of the terminals 1 to 3, changes in the flow rate values ​​561 to 563 are observed. Due to this consumption of compressed air, each of the pressure values ​​554 to 556 temporarily drops as shown in the graph 552. Here, even if the changes in the flow rate values ​​561 to 563 are the same at the terminals 1 to 3, the pressure fluctuation values ​​vary for each terminal as shown in 554 to 556. This is because the shapes, diameters (or cross-sectional areas) and lengths of the pipes from the discharge parts of the air compressors 2 to 4 to the terminals are different. By displaying the pressure and flow rate data of each terminal 1 to 3 side by side on the time axis in this way, the user 380 can confirm whether or not the pressure drops when a flow is generated (i.e., the valve is opened), and at what timing and how the pressure drops.

[0045] At the bottom of the frame of the actual measurement data 551, the data section 564 is specified by the user 380, and the prediction point L and delay point d are input in the columns 565 and 566. After inputting the data in the columns 564 to 566, the user 380 selects the model construction button 567, and the construction of the terminal pressure prediction model is executed. The pressure loss of each terminal predicted by the constructed terminal pressure prediction model is displayed in a graph 571 in the pressure loss confirmation 570 frame. As shown in the legend 572, "◯" indicates terminal 1, "△" indicates terminal 2, and "×" indicates terminal 3. In this way, the difference between the discharge pressure (or tank pressure) and the terminal pressure of terminals 1 to 3 is plotted against the flow rate, and further, the theoretical values ​​582 to 584 of the friction loss in the pipe for three typical shapes (diameter, length) of circular pipes are shown with dotted lines, so that the user can confirm that the differential pressure for the theoretical values ​​582 to 584 is appropriate (is of the same order as the friction in the pipe). The theoretical value can be calculated using the Darcy-Weisbach formula if the flow rate, diameter, and length at the end are known.

[0046] FIG. 6 is a diagram showing a system configuration when an actual facility is operated using the terminal pressure prediction model at the time of all terminal measurement in the embodiment of the present invention. The difference from FIG. 2 is that the pressure gauges (112, 123, ..., 244 in FIG. 2) installed at all terminals are removed, and devices that use compressed air are connected instead of the valves (111, 121, 241 in FIG. 2). The flow meters 112, 122, ..., 242 are left connected. The terminal pressure prediction control system 400 can continue to use the same device (for example, a personal computer) as shown in FIG. 2. In other words, the terminal pressure prediction control system 400 can be used not only for constructing the terminal pressure prediction model, but also as a system that controls the operation of the air compressor in the actual pneumatic facility using the constructed terminal pressure prediction model. When the terminal pressure predictive control system 400 is constructed on a personal computer, it may be realized by additionally installing a computer program that realizes the functions of the terminal pressure predictive control system 400 on a computer for controlling factory equipment, or it may be configured so that a part of the terminal pressure predictive control system 400 is installed and executed on another server. Furthermore, the terminal pressure predictive control system 400 for constructing a terminal pressure predictive model and a system for controlling the operation of an air compressor in an actual pneumatic facility using the constructed terminal pressure predictive model may be constructed on separate PCs, etc.

[0047] 6, when the pneumatic system shown on the left side is in operation, the outputs of the pressure gauges 305, 306, ..., 307 installed in the air compressors 2, 3, ..., 4 and the outputs of the flow meters 112, 122, ..., 242 installed in the pipes 11, 12, ..., 24 are transmitted to a terminal pressure prediction unit 402 of the terminal pressure prediction control system 400 via a communication network 360. The communication network 360 may be realized by a direct connection using a cable line, or by one-way or two-way communication using a wired or wireless network using an existing network.

[0048] During actual operation of the devices 115, 125, ..., 245, etc., an operating number / rotation speed operation unit 404 of the terminal pressure prediction control system 400 controls the operation of the multiple air compressors 2, 3, ..., 4. The terminal pressure prediction unit 402 acquires the outputs of the pressure gauges 305, 306, 307 and the outputs of the flow meters 112, 122, ..., 242 in real time via the communication network 360. The terminal pressure prediction unit 402 predicts the pressure supplied to the devices 115, 125, ..., 245 using the terminal pressure prediction model created in the procedures of Figures 3 and 4 and the measurement values ​​of the flow rates at each terminal that are actually measured, and a set pressure search unit 403 determines the discharge pressure (set pressure) of the air compressor supplied to the piping network 8 using the predicted value. The determined set pressure is sent to number of operating units / rotation speed operation unit 404, which selects air compressors 2, 3, ..., 4 to be operated and sets the operating rotation speed of the motor of the selected air compressor. A control signal from number of operating units / rotation speed operation unit 404 is transmitted to air compressors 2, 3, ..., 4 via control signal line 405, or wired or wireless communication using a communication network not shown, and air compressors 2, 3, ..., 4 operate according to the instructions of number of operating units / rotation speed operation unit 404.

[0049] FIG. 7 is a diagram showing an example of an input / output screen 470 in the input / output unit 410 in FIG. 6. This screen is a screen for accepting input information (control parameters, target pressure) by the user 80, and the terminal pressure prediction unit 402 displays the state of change in pressure at the terminals 11 and 21 (actual values ​​and future predicted values) when controlled according to the accepted input information. In the left frame of the screen 470, input fields for a control parameter input unit 471 and a target pressure input unit 475 are displayed. In the control parameter input unit 471, the user 80 inputs a control period 472 and a prediction score 473 using a keyboard or the like. The control period 472 is a period for controlling the discharge pressure from the air compressors 2, 3, ..., 4, and the prediction score 473 is a parameter that indicates how far into the future the pressure fluctuation from the present time is expected to be controlled. In the target pressure input unit 475, a pressure value to be the lower limit of the terminal 11 and the terminal 21 is input. When input into the control parameter input section 471 and the target pressure input section 475 is completed, the user 80 clicks on a control start icon 478, whereby operation control of the air compressor is executed using the created terminal pressure prediction model.

[0050] A monitor screen 480 for compressed air usage is displayed on the right side of the screen 470. Here, the usage of compressed air measured by the flow meters provided at the ends 11 and 21 is displayed in a graph. The horizontal axis represents the passage of time, and the vertical axis represents the usage of compressed air (unit: m 3 / min). The horizontal axis shows the amount of air used at end 11 up to the current time, and the amount of air used at end 21, 27. Below compressed air use amount monitoring screen 480, a terminal pressure control result monitoring screen 481 is displayed. In this field, the horizontal axis shows the passage of time, and the vertical axis shows the pressure value (unit: MPa).

[0051] The pressure 18 at the terminal 11 and the pressure 28 at the terminal 21 are displayed as estimated values ​​up to the current time when viewed in the horizontal axis direction. The reason why the pressures 18 and 28 are estimated values ​​is that when the air pressure equipment is in operation, the pressure gauges (113, 123, ..., 243 in Fig. 2) are removed from the air pressure terminals 11 and 21, and the pressures are calculated using the terminal pressure prediction model from the actual measured values ​​of the flow meters 111, 122, ..., 242. Furthermore, the predicted values ​​of the pressure 18 at the terminal 11 and the pressure 28 at the terminal 21 after the current time are displayed with dashed lines. The calculation of these predicted values ​​is performed by the terminal pressure prediction unit 402 using the terminal pressure prediction model stored in the model DB 430. At the bottom of the compressed air usage monitoring screen 480, the discharge pressure 37 of the air compressor is displayed with the actual value shown by the solid line and the predicted value shown by the dotted line. The actual value of the discharge pressure 37 is based on the measured value by the pressure gauges 305-307 provided in the air compressors 2-4 shown in FIG. 6. The predicted value shown by the dashed line is a value set by the set pressure search unit 403. In this way, during actual operation, the terminal pressure state (pressures 18, 28) and the discharge pressure 37 of the air compressor are displayed in real time on the display screen of the input / output unit 410, so that the air compressor can be operated appropriately according to the parameters input by the user 80 and the target pressure of the terminal pressure. Note that, although other terminal pressures (for example, 12-14, 22-24) are not shown in FIG. 7, it is possible to arbitrarily select which terminal pressure is to be displayed as the terminal to be displayed on the monitoring screen 481.

[0052] Next, a method for estimating the optimum pressure taking multiple terminals into consideration will be described with reference to FIG. 8. The set pressure search unit 403 monitors the pressure margin at multiple terminals to be measured according to the usage status of compressed air supplied via the piping network 8, predicts future demand, and controls the operation of the air compressors 2 to 4 so that the pressure at the terminal with the smallest pressure margin is set to above the lower limit. Specifically, the aim is to lower the discharge pressure of each of the air compressors 2 to 4 as much as possible, thereby operating the entire system efficiently and contributing to energy savings. FIG. 8A shows the amount of compressed air used per hour (unit: m) at terminal 11 and terminal 21 when there are two zones. 3 8A shows a graph of the amount of compressed air used at time t 1~t 4 Here, the amount of compressed air used at time t 1 ~t 2 Up to now, the usage of terminal 11 and terminal 21 is 0.5m 3 / min and time t 2 ~t 3 In this case, the usage amount of terminal 21 is 0.6m 3 / min, and at time t 3 Again 0.5m 3 / min. On the other hand, the terminal 11 shows the state where the current 1 ~t 3 It is constant until time t 3 The usage amount is 0.6m 3 / min.

[0053] The graphs of FIG. 8B and FIG. 8C show the pressure fluctuations at the ends 11 and 21 when the amount of compressed air used at the ends 11 and 21 is as shown in FIG. 8A. In FIG. 8B, the pressure at the end 11 in the zone 1 (measured by the pressure gauge 113 in FIG. 2) is 1 ~t 2 The pressure is about 0.66 MPaG, which is sufficiently larger than the target air pressure setting (lower limit) and is maintained at a high pressure value with a margin of about 10% from 0.6 MPaG. 2 In this case, the amount of compressed air used by the equipment connected to the terminal 21 is 0.6 m 3 / min, the discharge pressure 37 of the air compressor is controlled to rise suddenly from arrow 37a as shown by arrow 37b in Fig. 8D by the control of set pressure search unit 403 (see Fig. 6), following the increase in the amount of compressed air used at end 11. As a result of this temporary increase in discharge pressure 37, pressure 18 at end 11 temporarily increases as shown by arrow 18a to 18b, but in the case of the pneumatic equipment of this embodiment, pressure 18 immediately returns to its original value.

[0054] In FIG. 8C, the pressure at the end 21 (measured by the pressure gauge 213 in FIG. 1) 1 ~t 2Up to this point, the pressure is maintained at about 0.63 MPaG, with a small margin of about 5% from the set target air pressure value (lower limit). However, if the amount of compressed air used by both terminals 11 and 21 is less than the specified value of 0.5 m 3 / min, time t 1 ~t 2 The margin value near pressure 18d at end 11 is smaller than the margin value near pressure 28d at end 21. This magnitude relationship of margin values ​​occurs due to differences in piping structure (flow path resistance due to piping length, thickness, bending, etc.). 2 In this case, when the amount of compressed air used on the end 21 side increases as shown in Fig. 8A, the pressure 28 at the end 21 temporarily decreases as shown by arrow 28b. Here, the margin value 28c near the pressure 28a at the end 21 is small (small margin) at about 5%, so the pressure drop near arrow 28b falls below the lower limit of the target pressure, 0.6 MPaG, but it immediately returns to the original value due to the effect of the control that increases the discharge pressure 37 as shown by arrow 37b in Fig. 8D.

[0055] time t 3 In FIG. 8A, when the amounts of compressed air used 17, 27 shown in FIG. 8A increase on the end 11 side and return to the original amounts used on the end 21 side, as shown in FIG. 8D, the discharge pressure 37 of the air compressor in FIG. 8D is increased as indicated by arrow 37d by the control of set pressure search section 403 (see FIG. 2) so as to follow the increase in the amount used at end 11. At this time, although the pressure at end 11 temporarily decreases as indicated by arrow 18c in FIG. 8B, since the margin value of pressure 18 is set to a large value, even if the pressure decreases as indicated by arrow 18c, the target pressure lower limit value of 0.6 MPaG or more is maintained. Due to the effect of the control to increase discharge pressure 37 indicated by arrow 37d, as shown in FIGS. 8B and 8C, 3 After a short time the pressures at the ends 11, 21 will maintain their original values.

[0056] As described above, as shown in Fig. 8A to Fig. 8D, the terminal pressure predictive control system 400 uses the terminal pressure prediction model constructed by the terminal pressure prediction model construction unit 401 to monitor fluctuations in the usage status of compressed air at representative terminals of each zone, and the set pressure search unit 403 (see Fig. 6) monitors and predicts the pressure margin at multiple terminals according to fluctuations in the usage amount, and the operating number of units / rotation speed operation unit 404 sets the number of operating units and rotation speed of the multiple air compressors 2 to 4 so that the pressure at the terminal with the smallest pressure margin is equal to or higher than the lower limit. As a result, as shown in Fig. 8D, the set pressure search unit 403 (see Fig. 6) sets the number of operating units and rotation speed of the multiple air compressors 2 to 4 at time t 1 ~t 2 Section A up to time t 2 ~t 3 In the section B up to time t 3 In the following section C, the terminal 11 is the main object of control so that the pressure value of the terminal 11 does not fall below the lower limit. In this way, in the second embodiment, the user 380 inputs the specifications (lower limit pressure, rated air volume, frequency of use) of each device connected to the terminal, determines a representative terminal to be measured, and estimates the time change pattern of the terminal pressure based on the measured flow rate of the representative terminal and the terminal pressure prediction model, making it possible to reduce the discharge pressure of each terminal as much as possible using the terminal pressure prediction model according to the usage status of the compressed air. As a result, an air compressor control system that suppresses unnecessary power consumption and promotes energy saving has been realized.

[0057] Fig. 9 is a diagram showing an example of control for suppressing hunting due to a delay in the fluctuation of the terminal pressure in the terminal pressure prediction control system 400 of Fig. 2. The diagram in the box on the left shows the pressure fluctuation state when the terminal instantaneous value is fed back (FB) without considering the transmission delay of the terminal pressure fluctuation in the conventional control method, that is, a method that does not perform terminal pressure prediction control using a terminal pressure prediction model. The diagram in the box on the right shows the pressure fluctuation state when terminal pressure prediction control is performed using a terminal pressure prediction model according to an embodiment of the present invention. These controlled objects are for the pneumatic system shown in Fig. 1, where zone 1 and zone 2 are defined, and the pressure fluctuation of the terminal 11 is shown in zone 1, and the pressure fluctuation of the terminal 21 is shown in zone 2.

[0058] The top graph in the box on the left and right shows the amount of compressed air used (amount of compressed air used) at ends 11 and 21 (unit: m 3 / min) 171, 175. The horizontal axis is time. In both graphs, the time t 1 ~t 6 In the example, the compressed air consumption 171 and 175 of the terminal 11 is 2 The amount used is 0.5 m 3 / min to 0.6m 3 / min, while the compressed air consumption 271, 275 of the terminal 21 increases at time t 2 From 6 Usage up to 0.45m 3 The graphs in the boxes on the left and right show the pressure at the end 11 and the end 21 when the amounts of compressed air used 171 and 175 change.

[0059] In the box on the left showing the conventional example, at time t 2 When the amount of compressed air at the end 11 increases by about 20%, the pressure of the compressed air at the end 11 increases by about 20% at time t 2 ~t 3 In the figure, the pressure at end 21 on the zone 2 side decreases slightly as indicated by arrow 280a. This phenomenon does not directly correspond to an increase in compressed air usage 171 at end 11, but occurs with a delay relative to the change in the compressed air flow rate. Similarly, the pressure on the side of zone 1 where end 11 is provided decreases, and as a result, the pressure at end 21 on the side of zone 2 also decreases slightly as indicated by arrow 280a. The timing and magnitude of the effect of the decrease in pressure at end 11 on end 21 is greatly affected by the thickness and length of mother pipes 10 and 20, so what is shown here is merely one example.

[0060] In this way, at time t 2 ~t 3 When a pressure decrease occurs at , the pressure value is fed back (FB) to a conventional end pressure control system (not shown), and the end pressure control system controls the discharge pressure 370 of the air compressor as indicated by the arrow 370a at time t 2 From3 By this control of increasing the discharge pressure 370, the pressure at the end 11 increases with time lag as shown by the arrow 180b at time t 3 ~t 4 Since the main pipe 20 on the end 21 side is connected to the main pipe 10 on the end 11 side, the pressure at the end 21 decreases as shown by the arrow 280a, and then increases with a time delay as shown by the arrow 280b at time t 3 ~t 4 It increases slightly at

[0061] time t 4 At time t, the pressure at the end 11 recovers to the set pressure as indicated by the arrow 181. This recovery occurs when the discharge pressure 370 on the air compressor side falls to time t 3 In other words, the increased pressure of the arrow 371 is transmitted to the end 11. 4 -t 3 The tip pressure 370 is transmitted to the terminal 11 with a time difference of 180c and 180d. In feedback control, the presence of a transmission delay for such a change in tip pressure 370 leads to the occurrence of a hunting phenomenon in which pressure repeatedly increases and decreases, as shown by arrows 180c and 180d. In addition, since the occurrence of the hunting phenomenon at the terminal 11 is fed back, the terminal pressure control system controls the discharge pressure of the air compressor to vary so as to cancel the hunting phenomenon, and as a result, the discharge pressure 370 of the air compressor is increased and decreased as shown by arrows 370b to 370d, causing a hunting phenomenon 371. The occurrence of the hunting phenomenon due to the delay in the change in the terminal pressure not only leads to energy loss, but also wastes the power consumption of the air compressor, which is not preferable for energy saving.

[0062] The graph in the box on the right shows the control by the terminal pressure predictive control according to the embodiment of the present invention. 2 The amount of compressed air used at the terminal 11 is 0.5 m 3 / min to 0.6m 3 / min, the terminal pressure prediction unit 402 (see FIG. 6) predicts the pressure 185 at the terminal 11 and the pressure 285 at the terminal 21 for a certain section in the future. In this prediction, (a) the terminal pressure prediction unit 402 predicts the future values ​​of the terminal pressures 185, 285 at the terminals 11, 21 when the discharge pressure 375 of the air compressor is set to various pattern candidates, (b) searches for a prediction pattern that minimizes the cumulative error from the target value of the predicted terminal pressure, and (c) adopts the prediction pattern that minimizes the cumulative error determined by the search and predicts the future value of the terminal pressure 185, 285 at the terminal 21 for a certain section in the future (here, time t 2 ~t 4 ) air compressor.

[0063] In the bottom graph in the box on the right, at time t 2 In the figure, the terminal pressure prediction unit 402 prepares a plurality of change patterns of the protruding pressure 375 on the side of the air compressors 2 to 4. Three patterns are derived: discharge pressure 375a (first candidate) indicated by a thick solid line, discharge pressure 375b (second candidate) indicated by a dashed line, and discharge pressure 375c (third candidate) indicated by a dotted line. When these three patterns are calculated, the set pressure search unit 403 (see FIG. 6) determines which of these candidates is more suitable.

[0064] When the first to third change candidates 375a to 375c of the protruding pressure 375 are set in this way, the terminal pressure prediction unit 402 predicts the time t 2 ~t 4As a result of this prediction, three patterns are calculated for the terminal 11: pressure 185a (first candidate) shown by a thick solid line, pressure 185b (second candidate) shown by a dashed line, and pressure 185c (third candidate) shown by a dotted line. Similarly, for the terminal 21, pressure 285a (first candidate) shown by a thick solid line and pressure 285b (second candidate) shown by a dashed line are calculated. The third candidate 285c (third candidate) to be shown by a dotted line is the same as the second candidate, so it is shown by the same dotted line. Considering these candidates and the pressure fluctuations for the terminals 11 and 21, it can be determined that the air compressor should be controlled with the first discharge pressure 375a, which is the most preferable with less pressure fluctuation. The terminal pressure prediction unit 402 adopts the pressures 185a, 285a, and discharge pressure 375a of the first candidate, and by displaying their graphs by a thick solid line, it shows which candidate is adopted to the user 80 viewing the screen.

[0065] As described above, the terminal pressure prediction control system 400 searches for an optimal setting value for the discharge pressure of the air compressor using the terminal pressure prediction model, and controls the operation of the air compressor at the outlet pressure 375a determined by the search. When multiple air compressors are provided on the supply side of high-pressure air, the number of operating units / rotation speed operation unit 404 (see FIG. 6) of the terminal pressure prediction control system 400 controls the on / off control of each air compressor and even the rotation control of the motor that drives the compressor during operation.

[0066] In the right diagram of Figure 9, at time t 2 The terminal pressure prediction unit 402 predicts the pressures of the terminals 11 and 21 during the prediction period from time t 4 However, such a prediction is only valid until time t 2 Instead of doing it once at time t 2 Thereafter, the process continues at predetermined time intervals, and the optimal discharge pressure of the air compressor at each execution is set in sequence. 2 The interval until the next predictive control and the interval from the prediction start point to the prediction end point in each predictive control can be set arbitrarily, and the optimal time interval can be set taking into consideration the characteristics of the pneumatic equipment in the factory or work site.

[0067] FIG. 10 is a flowchart of compressor control in the terminal pressure prediction control system 400 in FIG. 6. The flowcharts in FIG. 10 and FIG. 11 described later are executed by the set pressure search unit 403 and the number of operating units / rotation speed operation unit 404, and are realized by a processor (not shown) included in the terminal pressure prediction control system 400 executing a specific computer program. First, the set pressure search unit 403 acquires a terminal pressure prediction model from the model DB 430 in which the created terminal pressure prediction model is stored (step 521). Next, the set pressure search unit 403 executes a plurality of steps 522 to 526 enclosed by a dashed line 527 at regular intervals. Steps 522 to 526 are a closed-loop control process executed at regular intervals.

[0068] In the closed loop control portion 527, the set pressure search portion 403 acquires the history of the discharge pressure and the terminal flow rate value of each of the air compressors 2 to 4 from an operation history database (not shown) (step 522). Next, the set pressure search portion 403 searches for the optimum value of the discharge pressure of the air compressors 2 to 4 in the next control cycle (step 523). Here, the detailed procedure of the portion of step 523 (subroutine for searching the optimum value of the discharge pressure) will be described with reference to the flowchart of FIG.

[0069] In FIG. 11, the set pressure search unit 403 first sets a candidate value for the discharge pressure in the next control cycle (step 531). Next, the set pressure search unit 403 predicts the terminal pressure for H cycles after the candidate value is held from the current time until the H cycles after (step 532). This prediction is performed by dividing the current time by t 0 Then, at time t=t 0 +Δt c From t=t 0 +HΔt c Compressor discharge pressure P comp (t) to P comp (t 0 ) + ΔP comp This is the end pressure when the pressure is held at Δt c (≧Δt) is the control period.

[0070] Next, the set pressure search unit 403 calculates the cumulative error of the terminal pressure until the predicted H cycle (step 533). Next, the set pressure search unit 403 calculates an evaluation function (step 534). This calculates the cumulative error and evaluation function according to the following formula.

[0071]

number

[0072] Next, it is determined whether the evaluation function shown in Equation 9 has converged (step 535). If the evaluation function has not converged, the candidate value for the discharge pressure is corrected and the process returns to step 531 (steps 535, 537). If the evaluation function has converged in step 535, the set candidate value is set as the discharge pressure in the next control cycle (step 536). This ΔP comp Using the searched value, the compressor discharge pressure is calculated according to the following equation 10.

[0073]

number

[0074] The value searched for in the subroutine of Fig. 11 is set as the discharge pressure of the air compressors 2 to 4, and is sent to the number of operating units / rotation speed operation unit 400 (step 524). The number of operating units / rotation speed operation unit 400 operates the number of operating air compressors and their respective rotation speeds so that the air compressors 2 to 4 are operated based on the designated value (step 525). Next, the processor of the terminal pressure prediction control system 400 judges whether or not to stop the control shown in Fig. 10, and if not, returns to step 522 at the next control period and repeats steps 522 to 526. If the processor judges in step 526 to stop the control of Fig. 10, the control is terminated.

[0075] As described above, the representative end flow rate and the actual measured value of the discharge pressure of the air compressor are input into the end pressure prediction model, and the function of predicting the representative end pressure thereafter is realized by the computer program, so that the optimal set pressure of the air compressor can be searched for such that the representative end pressure prediction value approaches the target pressure set by the user. This control makes it possible to control the number of operating air compressors and the rotation speed without waste. In addition, by optimizing the future values ​​of pressure at multiple ends, it is possible to suppress hunting 371 shown in Figure 9 and to achieve control tailored to the end 21 with little pressure margin. In this way, by measuring the actual air usage at all ends and estimating the optimal pressure taking all ends into consideration, optimal operation control of the air compressor is possible, and hunting suppression can be effectively achieved. The series of processes are model predictive control (MPC) and can be easily implemented using known OSS, libraries, or commercial technical calculation software. EXAMPLES

[0076] Next, a second embodiment of the present invention will be described with reference to Figs. 12 to 15. In the first embodiment, the actual air consumption is basically measured at all the terminals, and then the terminal pressure prediction model is created. During actual operation, the actual measured values ​​of the air consumption at all or some of the terminals and the terminal pressure prediction model are used to optimally control the operation of the air compressor. However, since the pneumatic equipment in a factory can range from small to large, and the number of pipes can range from tens to hundreds, it may be difficult to measure the pressure values ​​and air flow rates at all the terminals in order to create a terminal pressure prediction model. Therefore, in the case of air pressure in a large-scale pneumatic equipment, the piping pressure of the pneumatic equipment is divided into a plurality of zones, the pressure and air consumption at a representative terminal for each zone are measured, and a terminal pressure prediction model is created for each zone. During actual operation of the pneumatic equipment, the pressure gauge is removed from a representative terminal (note: there is no problem if it is left attached), the air consumption at each terminal is estimated, and this is input into the terminal pressure prediction model to predict the terminal pressure value. Based on this predicted value, the setting search unit 403 sets the optimal discharge pressure of the air compressor.

[0077] FIG. 12 is a configuration diagram showing a model operation configuration at the time of zoning in the terminal pressure prediction control system 400 according to the second embodiment of the present invention. The user 380 selects one "representative" pipe from each zone, installs pressure gauges 112, 362, etc. at the end of the representative pipe to measure the pressure value, and installs flow meters 112, 362, etc. to measure the pressure value and the amount of air used. Using these measured values ​​and the outputs of the pressure gauges 305 to 307, a terminal pressure prediction model for the selected end is created. During advance measurement for creating the terminal pressure prediction model, the user 360 divides the entire piping network into N zones (N>1) according to the physical characteristics of the piping network, such as the branching of the mother pipe, the shape of the piping (length, diameter, bend, etc.), and the presence or absence of loops. It is preferable that each zone includes one or several terminals. The user 380 who divides the zones 1 to N can be a user of the air pressure equipment, a serviceman in charge of the introduction and operation of the terminal pressure prediction control system 400, etc. Zoning is performed manually in this manner, and the zoning definition and representative point information are stored in an end definition database (DB) 440 by the user 380.

[0078] In Fig. 12, the equipment upstream from the piping network 8, i.e., air compressors 2, 3, ..., 4, pipes 302, 303, ..., 304 to the piping network 8, and pressure gauges 305, 306, ..., 307 for measuring air pressure, are the same as those shown in Fig. 2. A plurality of terminal pipes 11...14, 31-36 branch off from the piping network 8. Here, the illustration of the downstream side from the piping network 8 in terms of the flow of compressed air differs from that in Fig. 2, and only the piping portion corresponding to zone N is illustrated, but the configuration of the pneumatic equipment in the zones 1 and 2 is the same as that in the first embodiment.

[0079] The operator defines, for example, terminals 11 to 14 as zone 1 for multiple terminals 11...14, 31 to 36 connected from the piping network 8, and defines terminal 11 as the measurement target. These terminals 11 to 14 correspond to terminals 11 to 14 in the piping configuration shown in FIG. 1. Similarly, zoning is performed for multiple piping groups from zone 2 onwards, and in zone N not shown in FIG. 1, terminals 31 to 36 exist, and terminal 36 is set as the control target and the actual values ​​of flow rate and discharge pressure are measured. For these measurements, the user 380 removes the high-pressure air-using equipment (not shown) that is the supply destination of compressed air from the representative terminals of each terminal (terminals 11 and 36 in this case) and installs valves 111 and 361 instead. In addition, flow meters 112 and 362 and pressure gauges 113 and 363 are installed in the pipelines of terminals 11 and 36. In zones 2 to N-1 not shown, one representative terminal is also selected, and a valve, flow meter, and pressure gauge are set in the selected terminal. At the non-representative ends of zones 1 to N, no flow meter or pressure meter is separately connected, and the existing valve (not shown) is kept closed so that there is no compressed air from the ends.

[0080] A user 380 operates the valves, and the outputs of the flowmeters 111, 362 and the pressure gauges 113, 363 at each representative terminal at that time are recorded as actual measured values ​​of flow rate and discharge pressure in an experimental database (DB) 420 of a terminal pressure prediction control system 400 with the acquisition times synchronized. Note that, if acquisition of actual measured values ​​of flow rate and discharge pressure at all terminals in the first embodiment is completed before constructing a model operation during zoning in the second embodiment, a terminal pressure prediction model for each representative terminal may be constructed using the actual measured values ​​of all the terminals.

[0081] The model construction procedure after the measurement data is recorded in the experiment database 420 is basically the same as that in the first embodiment. By setting one representative terminal (or two or more, less than the total number of terminals) as in the second embodiment, it becomes easy to apply the air compressor pressure control system according to the present invention to pneumatic equipment in a facility such as a large-scale factory where there are several hundred terminal pipes.

[0082] Next, a method for defining terminal information will be described using terminal management table 450 in Fig. 13. First, at the time of measurement before constructing a model, user 380 defines each zone and a representative terminal (representative point) for each zone. Specifically, by regarding the area from branch 310 of mother pipe 300 to the ends of multiple terminal pipelines as one "zone," "zones" from 1 to N (N is a positive natural number) are defined, one representative terminal to be measured for each zone is set, and the pressure and flow rate of the set representative terminal are measured.

[0083] The terminal management table 450 in FIG. 13 is stored in advance in a terminal definition database (DB) 440 defined in a storage device (not shown) of the terminal pressure predictive control system 100, and defines a model operation configuration at the time of zoning in the terminal pressure predictive control system 400. The terminal management table 450 is roughly divided into a storage area for a terminal definition 451 and a flow information definition 461 for each terminal. The terminal definition 451 stores detailed information for each terminal that is uniquely defined by a terminal number 453. Here, the zones 1 and 2 corresponding to FIG. 1 and the parts corresponding to the respective terminal numbers 11 to 14 and 21 to 24 are illustrated. The representative point 454 is a representative point designated by the user 380, and one representative point 454 is selected for each zone. In the configurations of FIG. 1 and FIG. 7, the terminal number 11 of the zone 1 is selected, and the terminal number 21 is selected in the zone 2. A check mark indicating that it is representative is added to the representative point 454 column. Furthermore, additional information for identifying the representative point 454, for example, position-related information 455, is added to the representative terminals 11 and 21. As the position-related information 455, text, coordinate information, marks on a piping diagram, photographs, and other image information are stored. Here, the terminal with terminal number 453 "11" has a position description recorded in text information, such as "the end of the straight pipe extending directly from the compressor." Meanwhile, the terminal with terminal number 453 "21" has image data of the terminal position photographed by a still image camera, with the file name "zone2.jpg," stored as position-related information 455.

[0084] The flow rate information definition 461 for each terminal stores the rated air volume 462 and operation method 463 of the equipment connected to each terminal. The user 380 inputs the rated air volume 462, operation method 463, operation rate 464, and frequency 465 of the equipment used at each terminal. The rated air volume 462 is data displayed on a product nameplate or label that displays the model number and specifications of the connected equipment. The operation method 463 is data indicating whether the operation is a "continuous" operation that consumes compressed air continuously or an "intermittent" operation that consumes compressed air intermittently. The operation rate 464 indicates the ratio of operation time to stop time in the case of intermittent operation. The operation rate 464 may be obtained from a product nameplate or label, instruction manual, etc., or may be obtained by acquiring actual operation data. Here, the operation rate of the equipment connected to the terminal number "23" is 80%, and this can be calculated by tallying up the total operation time and the total stop time within a specified cycle time and calculating the ratio between them. The operation rate may be automatically acquired from monitoring data of a device using compressed air (not shown) and input. The frequency 465 stores the occurrence timing (cycle) of intermittent operation.

[0085] When the definition of the zone definition information and the equipment connected to the terminal is completed in the terminal management table 450, the terminal pressure prediction model construction unit 401 expands the constructed terminal pressure prediction model based on the zone definition information so that it can predict non-representative points as well. Specifically, from the matrix A and matrix B of the terminal pressure prediction model constructed for N representative points, components (submatrices) related to representative points belonging to the same zone as the non-representative point to be calculated are extracted and used as the terminal pressure prediction model for the non-representative point. The method of constructing the terminal pressure prediction model is the same as the method shown in the flowcharts of Figures 3 and 4, except that the number of terminals to be measured is reduced. The model formula used here can be calculated by the following formula 11.

[0086]

number

[0087] Then, using the created terminal pressure prediction model, terminal pressure prediction unit 402 (see FIG. 12) calculates an estimated value of a representative terminal pressure, and set pressure search unit 403 determines the discharge pressure of the air compressor that is in line with the estimated pressure value. Number of operating units / rotation speed operation unit (operation operation unit) 404 actually operates air compressors 2 to 4 according to the discharge pressure determined by set pressure search unit 403. In this way, it has become possible to optimally control the operation of the air compressors by measuring the actual air usage at a representative terminal of each zone and estimating the optimal pressure taking all terminals into consideration.

[0088] As described above, in the second embodiment, the area from the branch point 310 (see FIG. 1) of the mother pipe 300 to the end is regarded as one "zone", and the pressure and flow rate of one end are measured for each zone, and an end pressure prediction model for them is created. As an extended example of the second embodiment, it is possible to build an end pressure prediction model including an end that is not measured at the time of model construction from the end pressure prediction model created in the second embodiment. In other words, it is possible to build an extended end pressure prediction model including an end that is not measured at the time of model construction using learned parameters. The target of this extended end pressure prediction model is as shown in the schematic configuration diagram in FIG. 14, and 1a to 1c are included as the ends of zone 1, and 2a to 2c are included as the ends of zone 2.

[0089] FIG. 15 is an equation for the terminal pressure prediction model created in this modified example. Here, as shown in FIG. 12, a pressure meter and a flow meter are installed at representative terminals (e.g., terminals 1a and 2a), and pressure and flow data are measured in the same manner as in the first embodiment. Using the data, a terminal pressure prediction model for terminals 1a and 2a is constructed in the same manner as in the first embodiment. In this model, the pressure fluctuation characteristics of the terminals in each zone are considered to be the same, and a terminal pressure prediction model including terminals that have not been measured at the time of construction is constructed as in the equation of FIG. 15 using learned model parameters. Reference numeral 52 denotes a matrix coefficient A of the terminal pressure prediction model, and reference numeral 54 denotes a matrix coefficient B. These matrix coefficients A and B correspond to the matrix coefficients shown in equation 1.

[0090] Here, the meaning of the coefficients of the end pressure prediction model shown in FIG. 15 is as follows. The coefficient a including the parts indicated by the dotted lines 52a and 52d in the matrix coefficient A (arrow 52) 2m-1,1 , ..., a 2m-1,d (m=1, 2, ..., L) is a coefficient that represents the time evolution of pressure in zone 1, and includes the parts shown by dotted lines 52b and 52e. 2m,1 , ..., a 2m,d (m=1, 2, ..., L) is a coefficient that represents the time evolution of pressure in zone 2. The coefficient b (arrow 54) of the matrix B including the part surrounded by the dotted line 54a or the dotted line 54d and the dotted line 54f 2m-1,1 , ..., b 2m-1,1 (m=1, 2, ..., L) is a coefficient that represents the effect of the use of compressed air in zone 1. Coefficient b including the part surrounded by dotted line 54b or dotted line 54e and dotted line 54g in matrix coefficient B 2m,2 , ..., b 2m,2 (m=1, 2, ..., L) is a coefficient that represents the effect of the use of compressed air in zone 2. Coefficient b including the part surrounded by dotted line 54a or dotted line 54d and dotted line 54g in matrix coefficient B 2m-1,2 , ..., b 2m-1,2 (m=1, 2, ..., L) is a coefficient that represents the effect of the use of compressed air in zone 2 on zone 1. Coefficient b including the part surrounded by dotted line 54b or dotted line 54e and dotted line 54f in matrix coefficient B2m,1 , ..., b 2m,1 (m=1, 2, ..., L) is a coefficient that represents the effect of the use of compressed air in Zone 1 on Zone 2.

[0091] In the end pressure prediction model shown in Fig. 15, for the matrix coefficient A (first term on the right side) shown by reference numeral 52, if the end of the prediction target is zone 1, a coefficient representing the time development of pressure in said zone 1 is used, and if it is zone 2, a coefficient representing the time development of pressure in said zone 2 is used. For the matrix coefficient B (second term on the right side) shown by reference numeral 54, if the end of the prediction target is zone 1 and the end using compressed air is zone 1, a coefficient representing the effect of compressed air use in said zone 2 if the end of the prediction target is zone 2 and the end using compressed air is zone 2, a coefficient representing the effect of compressed air use in said zone 2 on zone 1 if the end of the prediction target is zone 1 and the end using compressed air is zone 2, and a coefficient representing the effect of compressed air use in said zone 1 on zone 2 if the end of the prediction target is zone 2 and the end using compressed air is zone 1 is used.

[0092] In this way, by modeling the time evolution of pressure and the characteristics of the effects of compressed air use for each zone based on the measurement data for each zone, and then using this to model other ends within the zone, it is possible to model the pressure transmission characteristics of large-scale piping with a minimal amount of work. EXAMPLES

[0093] FIG. 16 is a table summarizing the measurement points and operating characteristics in three usage forms of the compressor control system according to the present invention. The first one indicated by the number 601 is the compressor control system 1 described in the first embodiment. In the first embodiment, all terminals are basically the measurement targets as the measurement points 603 when constructing the model. Also, as for the flow rate information 604 for each terminal during actual operation after the model is created, the compressor is controlled using the measurement values ​​acquired at all or some of the terminals. As a result, hunting suppression is achieved as the output 605, and an estimate of the optimal pressure is obtained.

[0094] The second one indicated by the reference numeral 601 is the compressor control system 1 described in the second embodiment. In the second embodiment, as the measurement points 603 when constructing the model, the terminal group is divided into a plurality of zones, a representative terminal of each zone is selected, and the representative terminal is set as the measurement target and the measurement target of the flow rate during operation. Flow rate information 604 for each terminal during actual operation after the model is created is estimated from the use of all the equipment entered by the user without using a flow meter, and the compressor is controlled. As the output 605, hunting suppression and an estimate of the optimal pressure are obtained as in the first embodiment.

[0095] The third one indicated by the reference numeral 601 is related to the third embodiment described below. In the third embodiment, the compressor control system 1 is not used for direct control of the air compressors 2 to 4, but is used as an "energy saving diagnostic system" for judging energy saving in the operation of the air compressors 2 to 4. In the energy saving diagnostic system, for example, the measurement points 603 at the time of constructing the model can be all terminals, but it is also possible to measure only at representative points. In addition, the flow rate information 604 for each terminal during operation (diagnosis) can be obtained from all or some of the terminals to diagnose whether the operation settings of the air compressors are appropriate. In this energy saving diagnostic system, various calculations are performed on the customer's computer or the service provider's server, and the estimated optimal operating conditions and optimal pressure are outputted as outputs on the customer's computer or a mobile information terminal.

[0096] FIG. 17 is a configuration diagram of a compressor set pressure recommendation system according to a third embodiment of the present invention. The basic configuration is almost the same as that of FIG. 6, and the same reference numerals are used for the same components. Here, the compressor set pressure recommendation system 400A measures the flow rates of the terminals 11, 12, ... 24 in the air pressure system of the customer factory, diagnoses whether the set values ​​for the operation control of the multiple compressors 2 to 4 manually performed by the user 80 are appropriate, and displays the optimal recommended set value (recommended set pressure) on the input / output unit 410. The user 80 inputs the operation parameters (number of compressors, discharge pressure) of the air compressors 2 to 4 via the input / output unit 410, so that the set pressure search unit 403 displays the created terminal pressure prediction model, and displays the setting conditions (set pressure, etc.) of the air compressors on the input / output unit 410. The user 80, such as a person in charge of the production technology department of the customer factory, changes the set value to the compressor number control panel 390 by looking at the display result displayed on the input / output unit 410. The compressor number control panel 390 is a device for controlling the number of operating air compressors 2 to 4, the set pressure, and other set values.

[0097] FIG. 18 is an example of a display screen 570 in the input / output unit 410 when recommending compressor settings. In the image 570 displayed here, the graph in the column of compressed air usage 580 is the same as that shown in FIG. 9A. Also, the graph in the simulation screen 581 of the discharge pressure / terminal pressure is the same as that shown in FIG. 8B to FIG. 8D. In the target pressure input section 571 in the upper left of the image 570, a column 572 for inputting the target pressure of the terminal 11 and a column 572 for inputting the target pressure of the terminal 21 are provided. Note that, in FIG. 18, there are only two columns, 571 and 572, for inputting the target pressure, but it is also possible to provide input columns in the number corresponding to the number of zones in an actual pneumatic system or the total number of representative terminals.

[0098] After the user 80 inputs the target pressure values ​​to be set in each of the columns 572, 572, the terminal pressure prediction model constructed in the first or second embodiment is applied to calculate the optimal set pressures of the air compressors 2 to 4. The set pressure display section 574 is a column that displays the calculated optimal value 577. In FIG. 16, the current set pressure value 576 ("0.72 MPaG") and the calculated optimal value 577 ("0.62 MPaG") are displayed. From this result, the user can understand that the discharge pressure 37 of the air compressor can be reduced from the current 0.72 MPaG to 0.62 MPaG. As described above, according to the third embodiment, when the user 80 inputs the terminal target pressure, the set pressure at which the terminal pressure is closest to the target value when the usage amount at the current time is kept constant is calculated, and the set pressure can be displayed together with the predicted results of the discharge pressure and the terminal pressure.

[0099] Although the present invention has been described above using three embodiments, the present invention is not limited to the above-described embodiments, and various modifications are possible without departing from the spirit of the present invention. [Explanation of symbols]

[0100] 1. Pressure Control System 2~4 Air compressor 5~7 Pressure gauge 8 Piping network 10, 20, 60 main pipe 11~14, 21~24 Ends (ends of pipes) 111, 121, 131, 141 Valves 112, 122, 142 flowmeter 113, 123, 143 Pressure gauge 211, 221, 231, 241 Valves 212 Flow meter 213 Pressure Gauge 300 Main tube 302, 302, 304 Piping 305, 306, 307 Pressure Gauges 310 Branch 360 Network 380 users 400 Terminal pressure predictive control system 401 Terminal pressure prediction model construction section 402 Terminal pressure prediction unit 403 Set pressure search unit 404 Number of operating cars / rotation speed control unit 405 Control signal line 410 Input / output section 420 Experimental Database 430 Model Database 440 Terminal Definition Database 450 Terminal Management Table 451 Terminal definition 452 Zone 453 Terminal Number 454 Representative points 455 Location information 461 Flow information definition for each end 462 Rated air volume 463 Operation method 464 Occupancy rate 465 (operating) frequency 470 display screen

Claims

1. A compressor control system that controls equipment that supplies compressed air discharged from an air compressor to a plurality of terminals that consume the compressed air through a plurality of pipes, A pressure gauge is provided at one or more supply points near the air compressor or receiver tank; A pressure gauge, a flow meter, and a valve are connected to all or part of the ends of the piping, a storage means for storing data of pressure and flow rate measured by opening the end of the valve while changing the opening degree of the valve; A terminal pressure prediction model construction unit that uses the actually measured data to learn a terminal pressure prediction model having the pressure at the supply point and the flow rates at the terminals as inputs and the terminal pressure as an output; a terminal pressure prediction unit that predicts the pressure of the terminal by inputting a pressure measurement value of the supply point during actual operation of the equipment and flow rate information for each terminal into the learned terminal pressure prediction model; a set pressure searching unit that sets an optimal discharge pressure of the air compressor using the predicted end pressure value.

2. One or more air compressors are provided, The compressor control system according to claim 1, further comprising an operation control unit that controls the rotation speed and the number of operating air compressors so that the multiple terminal pressures set by the set pressure search unit fall within a predetermined range.

3. The compressor control system according to claim 2, characterized in that the terminal pressure prediction unit is used to control the rotation speed and the number of operating air compressors so that the multiple terminal pressures and future predicted values ​​of the discharge pressure of the air compressor are constant.

4. The terminal pressure prediction model construction unit uses many terminal pressure measurement values ​​and flow rate information when learning the terminal pressure prediction model, 4. The compressor control system according to claim 3, wherein the terminal pressure prediction unit makes a prediction when setting the optimum discharge pressure by using a smaller number of pieces of terminal flow rate information than when learning.

5. A plurality of branched portions of the piping are defined as zones, and a representative end for measuring a flow rate and a pressure is set for each zone; 5. The compressor control system according to claim 4, wherein the terminal pressure prediction unit sets the optimal discharge pressure of the air compressor by using representative actual measurement data of the terminal flow rate and pressure.

6. An input / output unit is provided for inputting and outputting information; a model database for storing the rated flow rate, operation method, and operation rate of the equipment connected to the terminal, which are input by a user; The terminal pressure prediction unit estimates a change pattern of the terminal flow rate from the input information, 6. The compressor control system according to claim 5, wherein the system predicts a future pressure change pattern based on a measured supply point pressure.

7. providing a display device for visually displaying information to a user; 6. The compressor control system according to claim 5, wherein the optimum discharge pressure of the air compressor set by the set pressure searching unit is displayed on the display device.

8. An input / output unit is provided for inputting and outputting information; In response to a user inputting a target pressure at the distal end from the input / output unit, 2. The compressor control system according to claim 1, wherein the set pressure searching unit simulates an optimal discharge pressure of the air compressor and displays the simulated optimal discharge pressure on the input / output unit.

9. A compressor control method for a pneumatic system in which compressed air discharged from an air compressor is supplied to a plurality of terminals consuming the compressed air via a plurality of pipes, using a control unit having a processor, and a terminal pressure predictive control system having an input / output device and a storage device connected to the control unit, comprising: The control unit is a) measuring a supply side pressure by a single or multiple pressure gauges provided on a discharge side that supplies compressed air to the multiple pipes; b) obtaining pressure and flow values ​​when the valve is opened or closed using a pressure gauge, a flow meter, and a valve provided at all or part of the end of the piping; c) learning a terminal pressure prediction model having a pressure for each terminal as an output using a supply pressure value from the air compressor and the pressure value and the flow rate value on the demand side; When the pneumatic system is in operation, the control unit d) connecting a compressed air utilizing device to the terminal in place of the valve; e) A compressor control method, comprising: calculating an optimal discharge pressure of the air compressor by inputting the supply pressure value and the flow rate value at the end into the end pressure prediction model.

10. One or more air compressors are provided, The compressor control method according to claim 9, wherein the control unit adjusts the rotation speeds of the air compressors and the number of operating air compressors so that the air compressors can be operated at the optimal discharge pressure set in step e).

11. In step d), the control unit calculates future predicted values ​​of the pressures at the terminals and the discharge pressure of the air compressor, The compressor control method according to claim 10, further comprising controlling the rotation speed of the air compressors and the number of operating compressors so that the future predicted value does not fall below a target value that is a lower limit of the terminal pressure.

12. The control unit is When learning the terminal pressure prediction model in the steps a) to c), many terminal pressure measurements and flow rate information are used, The compressor control method according to claim 11, wherein, during operation of the compressed air utilizing equipment in step e), flow rate information from the terminals is utilized in a number less than the number of measurements in step a).

13. providing a display device for visually displaying information to a user; The compressor control method according to claim 9, wherein the optimum discharge pressure of the air compressor set by the control unit is displayed on the display device.

14. An input / output unit is provided for inputting and outputting information; 10. The compressor control method according to claim 9, wherein the control unit simulates an optimal discharge pressure of the air compressor and displays it on the input / output unit in response to a user inputting the terminal target pressure from the input / output unit.

15. A compressor control method for a pneumatic system in which compressed air discharged from an air compressor is supplied to a plurality of terminals consuming the compressed air via a plurality of pipes, using a control unit having a processor, and a terminal pressure predictive control system having an input / output device and a storage device connected to the control unit, comprising: A plurality of branched portions of the piping are defined as zones, and a representative end for measuring a flow rate is set for each of the zones; The control unit is a) measuring a supply pressure value using a single or multiple pressure gauges provided on the discharge side of the multiple pipes that supplies compressed air; b) obtaining pressure measurement values ​​and flow measurement values ​​when the valve is opened or closed using a pressure gauge, a flow meter, and a valve provided at the representative terminal; c) learning a terminal pressure prediction model having a pressure for each terminal as an output using the supply pressure value, the pressure measurement value on the demand side, and the flow rate measurement value; When the pneumatic system is in operation, the control unit d) connecting a compressed air utilizing device to the representative terminal in place of the valve; e) A compressor control method, characterized in that an optimal discharge pressure of the air compressor is calculated by inputting the supply pressure value and the measured value of the flow rate for each representative terminal into the terminal pressure prediction model.

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