A machine tool airborne particulate concentration monitoring system

Abstract

The application provides a machine tool suspended particle concentration monitoring system, belonging to the field of cutting, which comprises a detection subsystem, a data transmission subsystem and a control subsystem; the detection subsystem and the data transmission subsystem are both arranged in a machine tool working chamber; the detection subsystem is used for emitting a measuring laser beam to a machine tool processing area in the machine tool working chamber and receiving a reflected light signal, and converting the reflected light signal into a suspended particle concentration voltage signal; the data transmission subsystem is used for transmitting the suspended particle concentration voltage signal to the control subsystem; the control subsystem is used for determining a fuzzy control signal according to the suspended particle concentration voltage signal and a pre-set fuzzy control query table, and performing fuzzy reasoning on the fuzzy control signal to obtain an accurate control signal, so as to control the concentration of suspended particles in the machine tool processing area. The application can monitor and control the concentration of suspended particles in the machine tool processing area in real time.

Description

Technical Field

[0001] This invention relates to the field of cutting, and in particular to a method for monitoring the concentration of suspended particulate matter in machine tools based on PLC control. Background Technology

[0002] In traditional machining processes, cutting fluid is increasingly considered an integral part of the machining process in order to improve machining efficiency, surface quality, and tool life. However, the vaporization and atomization of cutting fluid under high pressure and high temperature can form suspended particulate matter. Excessive concentration of these suspended particulate matter can damage the respiratory system and skin, causing irreversible diseases. Therefore, monitoring and control devices are still needed in actual manufacturing processes to monitor the concentration of suspended particulate matter.

[0003] Chinese invention patent application number CN201320015551.6 discloses a processor for a dual single-chip microcomputer oil mist monitoring system, including a main single-chip microcomputer and an auxiliary single-chip microcomputer. The main single-chip microcomputer and the auxiliary single-chip microcomputer communicate with each other. The main single-chip microcomputer is responsible for the overall scheduling, display and control of the entire monitoring system. The auxiliary single-chip microcomputer is connected to the probe of the monitoring system to manage and configure the probe.

[0004] Chinese utility model patent application number CN201822072922.X discloses an oil mist concentration detector, including a housing, an explosion-proof cover installed on the top of the housing, a circuit board, a terminal block, a sheath, a power supply, and a control system. The circuit board and terminal block are disposed inside the housing, while the sheath, power supply, and control system are disposed outside the housing. The terminal block is connected to the circuit board via terminal posts. The housing is connected to the sheath via a connecting pipe. A light source receiver is disposed inside the sheath, and a light-emitting diode is disposed inside the housing. The power supply is electrically connected to the light source receiver and the light-emitting diode via terminal posts. The wires connecting the light source receiver and the terminal posts are disposed inside the connecting pipe. The control system is electrically connected to the light source receiver and the light-emitting diode.

[0005] Chinese utility model patent application number CN201621213683.X discloses a processor for a dual-microcontroller oil mist monitoring system, including a base, a housing mounted on the top of the base, and a circuit board mounted on the bottom of the inner cavity of the housing. The circuit board includes a first microcontroller mounted on the left end and a second microcontroller mounted on the right end of the first microcontroller. A temperature sensor is mounted on the rear end of the circuit board, and a miniature fan is mounted on the rear end of the temperature sensor. The first and second microcontrollers are electrically connected. Through the coordinated use of the first and second microcontrollers, the first microcontroller is used to receive information and assign tasks, while the second microcontroller is used to assign management tasks assigned by the first microcontroller. This increases the data processing speed and keeps the oil mist concentration within a stable range, solving the problems of slow processing speed and unstable oil mist concentration control associated with using a single microcontroller in an oil mist system.

[0006] Chinese invention patent application number CN202110324626.8 discloses a processor for a dual microcontroller oil mist monitoring system. Its structure includes a fixing plate, threaded holes, a housing, a microcontroller, and a heat sink. The fixing plate and threaded holes are integrated, the housing is attached to the end face of the fixing plate, the microcontroller is embedded in the housing, and the heat sink is installed on the side of the microcontroller. This invention features a multi-layered protective film on the sensor end face of the microcontroller processor. The protective film is made of a thin, gauze-like material, and the end faces of the multi-layered protective films have corresponding lubricating liquids. When too much oil mist accumulates on the end face of the first protective film, its weight increases, causing the first protective film to detach directly. After the first protective film detaches, the subsequent protective films can promptly replace it, and this cycle repeats, effectively preventing the sensor from misjudging the oil mist value due to excessive oil mist.

[0007] A review of the above-mentioned inventions reveals that while they achieve the function of monitoring the concentration of suspended particulate matter with high accuracy, they do not control the concentration of suspended particulate matter. In addition, the microcontroller is expensive, and its anti-interference ability and stability are relatively weak, making it impossible to stably monitor the concentration of suspended particulate matter in the processing area. Summary of the Invention

[0008] The purpose of this invention is to provide a machine tool suspended particulate matter concentration monitoring system that can monitor and control the suspended particulate matter concentration in the machine tool processing area in real time.

[0009] To achieve the above objectives, the present invention provides the following solution:

[0010] A machine tool suspended particulate matter concentration monitoring system includes: a detection subsystem, a data transmission subsystem, and a control subsystem;

[0011] Both the detection subsystem and the data transmission subsystem are located in the machine tool working chamber. The detection subsystem is used to emit a measurement laser beam into the machine tool processing area in the machine tool working chamber and receive the reflected light signal, and convert the reflected light signal into a suspended particulate matter concentration voltage signal.

[0012] The data transmission subsystem is connected to the detection subsystem and the control subsystem respectively, and the data transmission subsystem is used to transmit the suspended particulate matter concentration voltage signal to the control subsystem;

[0013] The control subsystem is used to determine a fuzzy control signal based on the suspended particulate matter concentration voltage signal and a pre-set fuzzy control lookup table, and to perform fuzzy inference on the fuzzy control signal to obtain a precise control signal, so as to control the concentration of suspended particulate matter in the machine tool processing area.

[0014] Optionally, the detection subsystem includes: a detection module and a data processing module;

[0015] The detection module is used to emit a measuring laser beam into the machining area of ​​the machine tool and receive the reflected light signal, and convert the reflected light signal into a current signal;

[0016] The data processing module is used to convert the current signal into a voltage signal for suspended particulate matter concentration.

[0017] Optionally, the detection module includes a laser and a photodiode.

[0018] Optionally, the data transmission subsystem includes: a data bus, an RS232 module, an RS232 to RS485 converter, and an RS485 module;

[0019] The RS232 module is connected to the detection subsystem. The RS232 module is used to transmit the suspended particulate matter concentration voltage signal to the RS232 to RS485 module via the data bus using the RS232 protocol.

[0020] The RS232 to RS485 converter is used to transmit the received suspended particulate matter concentration voltage signal to the RS485 converter via the data bus using the RS485 protocol.

[0021] The RS485 module is connected to the control subsystem. The RS485 module is used to analyze the received suspended particulate matter concentration voltage signal and transmit it to the control subsystem.

[0022] Optionally, the control subsystem includes: a PLC controller, a frequency converter, and a fan; the fan is located outside the machine tool working chamber and is connected to the interior of the machine tool working chamber through an exhaust pipe;

[0023] The PLC controller is connected to the data transmission subsystem. The PLC controller is used to determine the fuzzy control signal based on the suspended particulate matter concentration voltage signal and a pre-set fuzzy control lookup table, and to perform fuzzy inference on the fuzzy control signal to obtain the precise control signal.

[0024] The frequency converter is connected to the PLC controller and the fan respectively. The frequency converter is used to adjust the frequency of the fan based on the precise control signal in order to control the concentration of suspended particulate matter in the machine tool processing area.

[0025] Optionally, the PLC controller is further configured to determine whether the concentration of suspended particulate matter in the machine tool processing area is greater than a preset limit value based on the suspended particulate matter concentration voltage signal; if so, an alarm signal is generated to trigger an alarm.

[0026] Optionally, the control subsystem further includes a touch screen; the touch screen is connected to the PLC controller, and the touch screen is used to display in real time the suspended particulate matter concentration limit value, the suspended particulate matter concentration in the machine tool processing area, and the alarm signal.

[0027] According to specific embodiments provided by the present invention, the present invention discloses the following technical effects: The present invention emits a measuring laser beam to the machine tool processing area through a detection subsystem in the machine tool workshop and receives the reflected light signal, converts the reflected light signal into a suspended particulate matter concentration voltage signal, thereby enabling real-time monitoring of the suspended particulate matter concentration in the machine tool processing area. The control subsystem determines the fuzzy control signal based on the suspended particulate matter concentration voltage signal and a pre-set fuzzy control lookup table, and performs fuzzy inference on the fuzzy control signal to obtain a precise control signal, so as to control the suspended particulate matter concentration in the machine tool processing area in real time. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 A simplified structural diagram of the machine tool suspended particulate matter concentration monitoring system provided by the present invention;

[0030] Figure 2 A schematic diagram of a human-computer interface for a touchscreen;

[0031] Figure 3 This is a diagram illustrating the alarm records generated by touching the screen during the processing.

[0032] Symbol explanation: 1-Detection subsystem, 2-Data transmission subsystem, 3-Control subsystem, 4-Detection module, 5-Data processing module, 6-RS232 module, 7-RS232 to RS485 module, 8-RS485 module, 9-Data bus, 10-PLC controller, 11-Inverter, 12-Fan, 13-Control bus. Detailed Implementation

[0033] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] The purpose of this invention is to provide a machine tool suspended particulate matter concentration monitoring system. A detection module and a data processing module are installed in the machine tool's working chamber. The detected data is encapsulated using a protocol and transmitted to a PLC controller via a data bus. The PLC program then processes and displays the data. By monitoring the received data, the PLC program executes different program modules to send instructions to the frequency converter. The frequency converter controls the frequency of the fan according to the instructions, thereby controlling the suspended particulate matter concentration in the machine tool's processing area within a predetermined range, thus enabling real-time monitoring of the suspended particulate matter concentration during processing.

[0035] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0036] like Figure 1 As shown, the machine tool suspended particulate matter concentration monitoring system provided by the present invention includes: a detection subsystem 1, a data transmission subsystem 2, and a control subsystem 3.

[0037] Both the detection subsystem 1 and the data transmission subsystem 2 are located in the machine tool working chamber. The detection subsystem 1 is used to emit a measurement laser beam into the machine tool processing area in the machine tool working chamber and receive the reflected light signal, and convert the reflected light signal into a suspended particulate matter concentration voltage signal.

[0038] Specifically, the detection subsystem 1 includes a detection module 4 and a data processing module 5.

[0039] The detection module 4 is used to emit a measuring laser beam into the machining area of ​​the machine tool and receive the reflected light signal, converting the reflected light signal into a current signal. In this embodiment, the detection module 4 includes a laser and a photodiode.

[0040] The measuring laser beam emitted by detection module 4 will scatter upon contact with suspended particles in the machine tool processing area. When the laser beam passes through air containing suspended particles, light scattering and absorption occur. The higher the concentration of suspended particles, the stronger the light scattering, resulting in attenuation of the light intensity in the original propagation direction. The generated scattered light is focused onto a photodiode by a lens, converting the optical signal into a current signal, which is then transmitted to data processing module 5.

[0041] The data processing module 5 is used to convert the current signal into a suspended particulate matter concentration voltage signal. In this embodiment, the data processing module 5 includes a processing circuit, a filtering and amplifying circuit, and a data acquisition circuit connected in sequence. The current signal received by the data processing module 5 passes through the processing circuit to convert the current signal into a voltage signal, then passes through the filtering and amplifying circuit, and finally the converted suspended particulate matter concentration voltage signal is transmitted to the data transmission subsystem 2 through the data acquisition circuit.

[0042] The data transmission subsystem 2 is connected to the detection subsystem 1 and the control subsystem 3 respectively. The data transmission subsystem 2 is used to transmit the suspended particulate matter concentration voltage signal to the control subsystem 3.

[0043] Specifically, the data transmission subsystem 2 includes: a data bus 9, an RS232 module 6, an RS232 to RS485 module 7, and an RS485 module 8.

[0044] RS232 module 6 is connected to the detection subsystem 1. RS232 module 6 is used to transmit the suspended particulate matter concentration voltage signal to RS232 to RS485 module 7 via the data bus 9 using the RS232 protocol.

[0045] The RS232 to RS485 module 7 is used to transmit the received suspended particulate matter concentration voltage signal to the RS485 module 8 via the data bus 9 using the RS485 protocol.

[0046] The RS485 module 8 is connected to the control subsystem 3. The RS485 module 8 is used to analyze the received suspended particulate matter concentration voltage signal and transmit it to the control subsystem 3.

[0047] Because the RS232 protocol is a one-to-one transmission with a short transmission distance of approximately 20 meters, while the RS485 protocol enables one-to-many communication, the PLC controller 10 can communicate with up to 128 sensors (detection subsystem 1) using RS485, with a transmission distance of up to thousands of meters. Therefore, the communication method of the detection subsystem 1 in this invention is the RS232 protocol, while the PLC controller 10 is an RS485 protocol module. Thus, during transmission, a data protocol conversion is required through the data transmission subsystem 2.

[0048] The control subsystem 3 is used to determine the fuzzy control signal based on the suspended particulate matter concentration voltage signal and a pre-set fuzzy control lookup table, and to perform fuzzy inference on the fuzzy control signal to obtain a precise control signal, so as to control the concentration of suspended particulate matter in the machine tool processing area.

[0049] Specifically, the control subsystem 3 includes a PLC controller 10, a frequency converter 11, and a fan 12. The fan 12 is located outside the machine tool working chamber and is connected to the interior of the machine tool working chamber through an exhaust pipe.

[0050] The PLC controller 10 is connected to the data transmission subsystem 2. The PLC controller 10 is used to determine the fuzzy control signal based on the suspended particulate matter concentration voltage signal and a pre-set fuzzy control lookup table, and to perform fuzzy inference on the fuzzy control signal to obtain the precise control signal.

[0051] First, fuzzy control rules are formed by combining the experience of on-site operators and the knowledge of experts. A fuzzy control lookup table is then determined based on these rules and written into the PLC register. This allows for querying the corresponding output quantity based on different inputs. The fuzzy control lookup table is analogous to a function; substituting the suspended particulate matter concentration into the table yields the corresponding fuzzy control signal. Subsequently, the maximum membership method or weighted average method is used to perform fuzzy inference on the fuzzy control signal to obtain the precise control signal.

[0052] In addition, the PLC controller 10 is also used to determine whether the concentration of suspended particulate matter in the machine tool processing area is greater than a preset limit value for suspended particulate matter concentration based on the suspended particulate matter concentration voltage signal; if so, an alarm signal is generated to trigger an alarm.

[0053] The frequency converter 11 is connected to both the PLC controller 10 and the fan 12. The frequency converter 11 is used to adjust the frequency of the fan 12 based on the precise control signal, thereby controlling the concentration of suspended particulate matter in the machine tool processing area and keeping the concentration within a predetermined range. Specifically, the frequency converter 11 is connected to the PLC controller 10 via a control bus 13.

[0054] In this invention, the PLC controller 10 uses PID fuzzy control to control the frequency converter 11, thereby controlling the fan 12. Specifically, firstly, the suspended particulate matter concentration limit value S is determined, and the suspended particulate matter concentration M is determined based on the suspended particulate matter concentration voltage signal. Then, the difference between the suspended particulate matter concentration limit value S and the suspended particulate matter concentration M is calculated to obtain the error e, and the rate of change of the error ec is determined. The error e and the rate of change of the error ec are fuzzified to obtain the fuzzy value E of the error and the fuzzy value EC of the error rate. The fuzzy value E of the error and the fuzzy value EC of the error rate are calculated according to the fuzzy control rules, that is, the fuzzy control lookup table is consulted based on the fuzzy value E of the error and the fuzzy value EC of the error rate to obtain the PID parameters (KP, KI, KD). Then, the PID parameters are defuzzified to obtain three positively tuned PID parameters. The PID controller controls the frequency converter 11 based on the positively tuned PID parameters.

[0055] Furthermore, the control subsystem 3 also includes a touch screen. The touch screen is connected to the PLC controller 10 and is used to display in real time the suspended particulate matter concentration limit value, the suspended particulate matter concentration in the machine tool processing area, and the alarm signal.

[0056] like Figure 2 As shown, the upper left corner of the touchscreen displays the real-time concentration of suspended particulate matter. The upper right corner of the touchscreen allows manual setting of the operating status of fan 12, while the lower right corner displays the operating status of fan 12. At the bottom of the touchscreen are two page buttons: "Main Page" and "Alarm View." Clicking the "Alarm View" page allows viewing the concentration of suspended particulate matter and the corresponding alarm timestamps during processing.

[0057] like Figure 3 As shown, alarm information generated during the processing is recorded on the touchscreen. Operators can view at any time when an alarm occurs, the concentration of suspended particulate matter that triggered the alarm, and the duration of the alarm. After viewing, the alarm needs to be cleared for the next test.

[0058] To better understand the technical solution of this invention, the process of monitoring the concentration of suspended particulate matter in machine tools is described below.

[0059] (1) Power on the data transmission subsystem 2, the detection subsystem 1 and the control subsystem 3, and set the operating conditions range corresponding to the PLC program.

[0060] (2) Open the PLC program and enable and communicate with the detection subsystem 1, data transmission subsystem 2 and control subsystem 3.

[0061] (3) When the system is working, if the concentration of suspended particulate matter in the machine tool processing area reaches the limit value of suspended particulate matter concentration, the touch screen will start an alarm and start the fan 12 through the PLC controller 10 for PID fuzzy control. At this time, the power of the fan 12 is at its minimum. As the concentration of suspended particulate matter increases, the working frequency of the fan 12 will continue to increase.

[0062] (4) After processing is completed, the machine tool suspended particulate matter concentration monitoring system continues to work. When the suspended particulate matter concentration in the machine tool processing area drops to the preset range, the PLC controller 10 is turned off.

[0063] Before the cutting process begins, the present invention first activates the control subsystem 3, the detection subsystem 1, and the data transmission subsystem 2. During the processing, the detection subsystem 1 monitors the changes in the concentration of suspended particulate matter in the machine tool's processing area in real time, and transmits this data to the control subsystem 3 via the data transmission subsystem 2. The control subsystem 3 then performs fuzzy control on the fan 12 based on the received data. Additionally, the operator can view the real-time changes in the suspended particulate matter concentration via a touchscreen and adjust the power of the fan 12 using the touchscreen as well.

[0064] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. Furthermore, those skilled in the art will recognize that, based on the ideas of the present invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A machine tool suspended particulate matter concentration monitoring system, characterized in that, The machine tool suspended particulate matter concentration monitoring system includes: a detection subsystem, a data transmission subsystem, and a control subsystem; Both the detection subsystem and the data transmission subsystem are located in the machine tool working chamber. The detection subsystem is used to emit a measurement laser beam into the machine tool processing area in the machine tool working chamber and receive the reflected light signal, and convert the reflected light signal into a suspended particulate matter concentration voltage signal. The detection subsystem includes a detection module and a data processing module; the detection module is used to emit a measuring laser beam into the machine tool processing area and receive the reflected light signal, converting the reflected light signal into a current signal; the detection module includes a laser and a photodiode; the data processing module is used to convert the current signal into a suspended particulate matter concentration voltage signal; The laser beam emitted by the detection module will be scattered when it comes into contact with suspended particles in the machine tool processing area. When the laser beam passes through the air containing suspended particles, light scattering and absorption will occur. The higher the concentration of suspended particles, the stronger the light scattering, which causes the light intensity to be attenuated in the original propagation direction. The scattered light is focused on the photodiode by the lens to convert the light signal into a current signal, and the current signal is transmitted to the data processing module. The data transmission subsystem is connected to the detection subsystem and the control subsystem respectively, and the data transmission subsystem is used to transmit the suspended particulate matter concentration voltage signal to the control subsystem; The control subsystem is used to determine a fuzzy control signal based on the suspended particulate matter concentration voltage signal and a pre-set fuzzy control lookup table, and to perform fuzzy inference on the fuzzy control signal to obtain a precise control signal, so as to control the concentration of suspended particulate matter in the machine tool processing area. The control subsystem includes a PLC controller, a frequency converter, and a fan. The fan is located outside the machine tool working chamber and is connected to the interior of the machine tool working chamber via an exhaust pipe. The PLC controller is connected to the data transmission subsystem and is used to determine a fuzzy control signal based on the suspended particulate matter concentration voltage signal and a pre-set fuzzy control lookup table, and to perform fuzzy inference on the fuzzy control signal to obtain a precise control signal. The frequency converter is connected to both the PLC controller and the fan, and is used to adjust the frequency of the fan based on the precise control signal to control the concentration of suspended particulate matter in the machine tool processing area. The PLC controller employs PID fuzzy control to control the frequency converter, thereby controlling the fan. Specifically, the process begins by determining the suspended particulate matter concentration limit S, then determining the suspended particulate matter concentration M based on the suspended particulate matter concentration voltage signal. The difference between the suspended particulate matter concentration limit S and the suspended particulate matter concentration M is then calculated to obtain the error e, and the rate of change of the error ec is determined. The error e and the rate of change of the error ec are then fuzzified to obtain the fuzzy value E of the error and the fuzzy value EC of the error rate. These fuzzy values ​​E and EC are then calculated according to fuzzy control rules, specifically by querying a fuzzy control lookup table based on the fuzzy values ​​E and EC to obtain the PID parameters. Finally, the PID parameters are defuzzified to obtain three positively tuned PID parameters. The PID controller then controls the frequency converter based on these positively tuned PID parameters.

2. The machine tool suspended particulate matter concentration monitoring system according to claim 1, characterized in that, The data transmission subsystem includes: a data bus, an RS232 module, an RS232 to RS485 converter module, and an RS485 module; The RS232 module is connected to the detection subsystem. The RS232 module is used to transmit the suspended particulate matter concentration voltage signal to the RS232 to RS485 module via the data bus using the RS232 protocol. The RS232 to RS485 converter is used to transmit the received suspended particulate matter concentration voltage signal to the RS485 converter via the data bus using the RS485 protocol. The RS485 module is connected to the control subsystem. The RS485 module is used to analyze the received suspended particulate matter concentration voltage signal and transmit it to the control subsystem.

3. The machine tool suspended particulate matter concentration monitoring system according to claim 1, characterized in that, The PLC controller is also used to determine whether the concentration of suspended particulate matter in the machine tool processing area is greater than a preset limit value based on the suspended particulate matter concentration voltage signal; if so, an alarm signal is generated to trigger an alarm.

4. The machine tool suspended particulate matter concentration monitoring system according to claim 3, characterized in that, The control subsystem also includes a touch screen; the touch screen is connected to the PLC controller, and the touch screen is used to display the suspended particulate matter concentration limit value, the suspended particulate matter concentration in the machine tool processing area, and the alarm signal in real time.

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