Temperature signal and three-axis cutting force signal online measuring device for turning process

Abstract

The invention relates to a temperature signal and three-axis cutting force signal online measuring device for a turning process. A temperature signal and three-axis cutting force signal online measuring device used in the turning process comprises a tool rest, a diamond self-temperature-sensing tool, a strain type three-axis force sensor and a sensor signal collecting circuit, and the diamond self-temperature-sensing tool is installed at the front end of the strain type three-axis force sensor; the strain type three-axis force sensor comprises three pressure sensors, cutting force borne by the diamond self-temperature-sensing tool is transmitted to the three pressure sensors through the tool rest, and the pressure sensors are distributed according to the X axis, the Y axis and the Z axis of a space rectangular coordinate system. According to the device, machining and detection integration in the machining cutting process is achieved, and high-sensitivity and high-response-speed real-time synchronous measurement of a temperature signal and a three-axis cutting force signal of a cutting area in the cutting process can be achieved.

Description

Technical Field

[0001] The invention relates to an online measuring device for temperature signals and three-axis cutting force signals in a turning process. Background Art

[0002] As an important part of mechanical manufacturing, cutting processing and its inspection technology are an important field of development in the current mechanical and manufacturing engineering disciplines. In order to evaluate the quality of cutting surfaces and optimize cutting processes, online monitoring of cutting conditions is indispensable. The cutting process is accompanied by complex thermal-mechanical coupling interactions. Cutting force and cutting temperature are important indicators for measuring cutting conditions such as machining surface size, shape accuracy, cutting chatter, and tool wear. Therefore, by sensing the size of cutting force and cutting temperature in real time, online monitoring of cutting conditions can be effectively achieved, thereby ensuring and optimizing the machining process. Especially for a class of materials with strong thermal sensitivity and poor stability, such as energetic materials that are used as power sources and power sources for weapons and equipment to achieve long-range efficient destruction and precise strikes, online and accurate monitoring of cutting area temperature and force during their machining is crucial to ensuring machining surface quality and improving process safety. In addition, for difficult-to-machine materials with extremely low thermal conductivity, such as carbon fiber composites, online measurement of cutting temperature and cutting force can effectively avoid carbonization of the machining surface and excessive tool wear, reduce scrap rate, and improve machining efficiency. Therefore, real-time synchronous measurement of cutting temperature and cutting force in actual cutting is of great significance. Summary of the invention

[0003] The purpose of the present invention is to provide an online measuring device for temperature signals and three-axis cutting force signals in a turning process, which is conducive to the synchronous measurement of cutting temperature and three-axis cutting force in the cutting process with high sensitivity, high precision and high response speed.

[0004] To achieve the above object, the present invention adopts the following technical scheme: an online measurement device for temperature signal and three-axis cutting force signal in turning process, comprising a tool holder, a diamond self-sensing temperature tool, a strain type three-axis force sensor and a sensor signal acquisition circuit, wherein the diamond self-sensing temperature tool is installed at the front end of the strain type three-axis force sensor, the strain type three-axis force sensor is installed at the front half of the tool holder, and the sensor signal acquisition circuit is installed at the rear half of the tool holder; The diamond self-temperature sensing tool measures the resistance value and converts it into a temperature signal through the temperature-resistance function relationship; The strain type three-axis force sensor includes three pressure sensors. The cutting force of the diamond self-temperature sensing tool is transmitted to the three pressure sensors by the tool holder. The pressure sensors are distributed according to the three axes of the spatial rectangular coordinate system XYZ. The pressure sensors output voltage signals under the action of the piezoresistive effect. The sensor signal acquisition circuit includes a power supply circuit, a signal pre-processing circuit and a signal sampling circuit. The sensor signal acquisition circuit provides a microampere-level constant excitation current for the diamond self-sensing temperature-sensing tool. Under the action of this current, the diamond self-sensing temperature-sensing tool outputs a voltage signal to the signal acquisition circuit. The signal pre-processing circuit integrates a differential signal amplification unit and a constant current source unit, and the signal sampling circuit integrates a digital-to-analog conversion unit and a data sending unit.

[0005] Preferably, the voltage signal of the three-axis force obtained by the sensor signal acquisition circuit is coupled, and a sensitivity coefficient matrix is ​​used to perform decoupling operation to obtain the magnitude of the three-axis force. The sensitivity coefficient matrix is ​​obtained by a uniaxial force test experiment, and the coupling relationship between the cutting force in three directions and the three-axis voltage signal is measured respectively. The three independent force signals obtained after decoupling are combined to obtain a complete force vector result.

[0006] Preferably, the differential signal amplification unit is constructed using four AD8421 instrument amplifiers, and the four AD8421 instrument amplifiers correspond one-to-one to three cutting force signals and one temperature signal. The constant current source unit is constructed using an LM334 chip, the digital-to-analog conversion unit is constructed using an AD7606 chip, and the data sending unit is constructed using an STM32F103C8T6 microcontroller and a MAX485 chip. The differential signal amplification unit is constructed using an AD8421 instrument amplifier to map the voltage signal to an observable range, and the voltage analog signal is quantified using an AD7606 low-cost analog-to-digital conversion solution, and the obtained digital signal is sent to the STM32F103C8T6 microcontroller.

[0007] Preferably, the constant current source unit is a microampere-level constant excitation current output unit, which is a constant current source circuit with the LM334 power chip as the core, and uses a negative temperature coefficient silicon diode 1N457 to compensate for the temperature drift of the chip when it is working.

[0008] Preferably, the digital-to-analog conversion unit is based on the AD7606 eight-channel analog-to-digital conversion chip, and is connected to the analog-to-digital conversion unit from the differential amplifier unit through a voltage signal interface. The voltage signal interface receives the sensor signal from the signal pre-processing module. After passing through AD7606, the signal is quantized into a digital signal and transmitted to the microprocessor STM32F103C8T6 via SPI.

[0009] Preferably, the input power supply of the power input interface of the power supply circuit is a 10-16V DC power supply. After the input power supply +Vin passes through two voltage conversion modules, it is inverted and stepped down. The obtained positive voltage is output after passing through a low voltage difference linear regulator and a low voltage difference linear regulator in turn, and the obtained negative voltage is output after passing through a low voltage difference linear regulator.

[0010] As a preference, the output triaxial force Fx 、F y 、F z The corresponding three-way voltage signal is recorded as V x 、V y 、V z , the three-axis forces are coupled, that is, the output signal V x ≠0, V y ≠0, V z ≠0, F x 、F y 、F z All V x 、V y 、V z Function of three voltage output quantities, F x =f x (V x 、V y 、V z )、F y =f y (V x 、V y 、V z )、F z =f z (V x 、V y 、V z ), f x 、f y 、f z These are three highly linear functions that can be written as F x =A1(V x -V x0 )+B1(V y -V y0 )+C1(V z -V z0 ), F y =A2(V x -V x0 )+B2(V y -V y0 )+C2(V z -V z0 ), F z =A3(V x -V x0 )+B2(V y -V y0 )+C2(V z -V z0 ); Among them, V x0 、V y0 、V z0 is the initial output value, that is, the output is cleared to zero. remember , Then F=M(V-V0), The inverse matrix of the sensitivity coefficient matrix M V-V0=M -1 F By applying uniaxial forces in the X, Y, and Z directions respectively, the three parameters corresponding to the X, Y, and Z directions can be solved respectively, so as to solve all the parameters and thus solve the sensitivity coefficient matrix M.

[0011] The device of the present invention realizes the integration of machining and detection of the mechanical machining cutting process, and can achieve real-time synchronous measurement of the temperature signal of the cutting area and the three-axis cutting force signal with high sensitivity and high response speed during the cutting process. The invention has extremely strong practicality and broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a schematic diagram of the structure of the device according to an embodiment of the present invention.

[0013] Figure 2 It is a schematic diagram of a sensor signal acquisition circuit and a signal pre-processing circuit in an embodiment of the present invention.

[0014] Figure 3 It is a schematic diagram of a sensor signal acquisition circuit - a signal sampling circuit in an embodiment of the present invention.

[0015] Figure 4 This is a wiring diagram of the sensor signal acquisition circuit—the signal sampling circuit AD7606 and the STM32 in an embodiment of the present invention.

[0016] Figure 5 It is a schematic diagram of a sensor signal acquisition circuit-power supply circuit in an embodiment of the present invention.

[0017] Figure 6 It is a schematic diagram of the sensor signal acquisition circuit-power supply circuit output voltage configuration principle in an embodiment of the present invention.

[0018] Figure 7 Schematic diagram of the structure of a strain type three-axis force sensor in an embodiment of the present invention. DETAILED DESCRIPTION

[0019] The present invention will be further described below based on the accompanying drawings and specific embodiments.

[0020] like Figures 1 to 7As shown, this embodiment discloses an online measurement device for temperature signal and three-axis cutting force signal in turning process, including a tool holder 21, a diamond self-temperature sensing tool 5, a strain-type three-axis force sensor 3 and a sensor signal acquisition circuit 7. The diamond self-temperature sensing tool 5 is installed at the front end of the strain-type three-axis force sensor 3 through a hexagon socket screw and a nut. The strain-type three-axis force sensor 3 is installed at the front half of the base 6 of the tool holder 21 through eight M4 screws 4. The sensor signal acquisition circuit 7 is installed at the rear half of the base 6 of the tool holder 21. Among them, the diamond self-temperature sensing tool 5 measures its resistance value and then converts it into a temperature signal through the temperature-resistance function relationship.

[0021] The strain type three-axis force sensor 3 of this embodiment includes three DYZ-100 pressure sensors 20 of Bengbu Dayang Sensing Company of China. The cutting force exerted on the diamond self-temperature sensing tool 5 is transmitted to the three pressure sensors 20 by the tool holder 21. The pressure sensors 20 are distributed according to the three axes of the spatial rectangular coordinate system XYZ. The pressure sensors 20 output voltage signals under the action of the piezoresistive effect.

[0022] The sensor signal acquisition circuit 7 of this embodiment includes a power supply circuit 10, a signal pre-processing circuit 8 and a signal sampling circuit 9. The sensor signal acquisition circuit 7 provides a constant excitation current of microamperes for the diamond self-sensing temperature-sensing tool 5. Under the action of this current, the diamond self-sensing temperature-sensing tool 5 outputs a voltage signal to the signal acquisition circuit. The signal pre-processing circuit 8 integrates four differential signal amplification units 12 and a constant current source unit 11. The signal sampling circuit 9 integrates a digital-to-analog conversion unit 13 and a data sending unit 14.

[0023] Among them, the circuit boards of the power supply circuit 10, the signal pre-processing circuit 8 and the sensor signal sampling circuit 9 are installed in the base 6 in an up-and-down stacking manner. A top cover 1 is provided on the top of the base 6, and the top cover 1 and the base 6 are installed together by M2 screws 2; the tool holder 21 of this embodiment is a 7051 aluminum alloy tool holder, and the selection of the 7051 aluminum alloy tool holder is to ensure the low mechanical inertia of the entire device.

[0024] like Figure 2As shown in the figure, the differential signal amplification unit is a differential amplifier circuit with the AD8421 instrumentation amplifier chip as the core. The differential signal amplification unit is constructed using four AD8421 instrumentation amplifiers, and the four AD8421 instrumentation amplifiers correspond to three cutting force signals and one temperature signal. The amplification factor of AD8421 is 990 using a 10 ohm resistor. The microampere constant excitation current output unit is a constant current source circuit with the LM334 power chip as the core, and the negative temperature coefficient silicon diode 1N457 is used to compensate for the temperature drift of the chip during operation. The LM334 chip peripheral feedback network is configured with two resistors to obtain a constant current source output size of 10μA. For the specific implementation method of the AD8421 instrumentation amplifier amplification configuration, refer to the AD8421 data sheet provided by ANALOGDEVICES, and for the specific implementation scheme of the LM334 output current configuration, refer to the LM334 data sheet provided by Texas Instruments. Among them, the resistance configuration scheme principle disclosed in the patent application number 202411120880.6 is used to configure the resistance to obtain a suitable current size to compensate for the temperature drift.

[0025] like Figure 3 As shown in the figure, the digital-to-analog conversion unit is based on the AD7606 eight-channel analog-to-digital conversion chip. The voltage signal interface is connected from the differential amplifier unit to the analog-to-digital conversion unit. The voltage signal interface receives the sensor signal from the signal pre-processing module. After passing through the AD7606, the signal is quantized into a 16-bit digital signal and transmitted to the microprocessor STM32F103C8T6 through SPI.

[0026] Among them, the wiring diagram of AD7606 and STM32 is in Figure 4Given in, where +5V is the power supply line of AD7606, +2.5V is the external reference voltage, and GND is the common ground level of AD7606 and STM32. CS is the chip select signal of the SPI line, connected to the PC3 pin of STM32. RD / SCLK is the clock signal of SPI, connected to the PA5 pin of STM32. DB7 / DOUT is the data signal of SPI, connected to the PA6 pin of STM32. RAGE is the range configuration of AD7606, and the range is configured to ±5V when grounded. RST is the reset signal, connected to the PB13 pin of STM32. CVA is connected in parallel with CVB, and is the start analog-to-digital conversion signal, connected to the PB12 pin. OS0, OS1, and OS2 are oversampling configuration signals, and all grounding cancels the oversampling function of AD7606. The data transmission unit 14 is constructed using the STM32F103C8T6 microcontroller and the MAX485 chip. STM32F103C8T6 is the control core of the data transmission unit 14. Its program operation cycle is 1ms. After the data is packaged, it is sent to the module data output terminal through the serial port. The 8MHz passive crystal oscillator ensures the time accuracy of the program operation cycle. The data output terminal, that is, the 485 interface uses the Max485 chip to convert the serial port TTL level into a 5V 485 signal.

[0027] like Figure 5 As shown, the input power of the power input interface of the power supply circuit is a 10-16V DC power supply. After the input power +Vin passes through two voltage conversion modules (K7809-500R3 module 15), it is inverted and stepped down to ±9V voltage. Among them, the +9V voltage is converted into a +5V voltage signal by a low-dropout linear regulator (TPS7A4901 power chip 16), and is also converted into a +3.3V voltage signal by a low-dropout linear regulator (AMS1117-3.3 chip 18). The -9V voltage is converted into a -5V voltage signal by a low-dropout linear regulator (TPS7A3001 power chip 17). All voltage signals are connected to the output port of the power module. The output voltages of TPS7A4901 and TPS7A3001 are configured using feedback resistors. The configuration scheme is as follows: Figure 6 shown.

[0028] Output voltage With feedback resistor and The calculation relationship is

[0029] Pick ,when hour, .

[0030] It is a chip ceramic capacitor packaged as C0603, and its capacitance is given in the figure.

[0031] The voltage signal of the three-axis force obtained by the sensor signal acquisition circuit is coupled. The sensitivity coefficient matrix is ​​used to perform decoupling operation to obtain the size of the three-axis force. The sensitivity coefficient matrix is ​​obtained by the uniaxial force test experiment. The coupling relationship between the cutting force in three directions and the three-axis voltage signal is measured respectively. The three independent force signals obtained after decoupling are combined to obtain a complete force vector result.

[0032] Output triaxial force F x 、F y 、F z The corresponding three-way voltage signal is recorded as V x 、V y 、V z , the three-axis forces are coupled, that is, the output signal V x ≠0, V y ≠0, V z ≠0, F x 、F y 、F z All V x 、V y 、V z Function of three voltage output quantities, F x =f x (V x 、V y 、V z )、F y =f y (V x 、V y 、V z )、F z =f z (V x 、V y 、V z ), f x 、f y 、f z These are three highly linear functions that can be written as F x =A1(V x -V x0 )+B1(V y -V y0 )+C1(V z -V z0 ), F y =A2(V x -V x0 )+B2(V y -V y0 )+C2(V z -V z0 ), F z=A3(V x -V x0 )+B2(V y -V y0 )+C2(V z -V z0 ); Among them, V x0 、V y0 、V z0 is the starting output value, that is, the output is cleared to zero. remember ,, Then F=M(V-V0), The inverse matrix of the sensitivity coefficient matrix M is relatively easy to measure experimentally. V-V0=M -1 F At this time, we only need to apply uniaxial forces in the X, Y, and Z directions to solve M. -1 Corresponding to the three parameters of X, Y, and Z directions, M can be solved -1 All nine parameters in total are taken to solve the sensitivity coefficient matrix M.

[0033] This embodiment provides a real-time synchronous measurement device for force and temperature in the cutting process for the field of mechanical manufacturing. The device realizes the integration of processing and detection of the mechanical machining cutting process, and can realize real-time synchronous measurement of the temperature signal of the cutting area and the three-axis cutting force signal of the cutting process with high sensitivity and high response speed. It has extremely strong practicality and broad application prospects.

Claims

1. An online measuring device for temperature signal and three-axis cutting force signal in turning process, characterized in that: It includes a tool holder, a diamond self-sensing temperature tool, a strain-type three-axis force sensor and a sensor signal acquisition circuit, wherein the diamond self-sensing temperature tool is installed at the front end of the strain-type three-axis force sensor, the strain-type three-axis force sensor is installed at the front half of the tool holder, and the sensor signal acquisition circuit is installed at the rear half of the tool holder; The diamond self-temperature sensing tool measures the resistance value and converts it into a temperature signal through the temperature-resistance function relationship; The strain type three-axis force sensor includes three pressure sensors. The cutting force of the diamond self-temperature sensing tool is transmitted to the three pressure sensors by the tool holder. The pressure sensors are distributed according to the three axes of the spatial rectangular coordinate system XYZ. The pressure sensors output voltage signals under the action of the piezoresistive effect. The sensor signal acquisition circuit includes a power supply circuit, a signal pre-processing circuit and a signal sampling circuit. The sensor signal acquisition circuit provides a microampere-level constant excitation current for the diamond self-sensing temperature-sensing tool. Under the action of this current, the diamond self-sensing temperature-sensing tool outputs a voltage signal to the signal acquisition circuit. The signal pre-processing circuit integrates a differential signal amplification unit and a constant current source unit, and the signal sampling circuit integrates a digital-to-analog conversion unit and a data sending unit.

2. The temperature signal and three-axis cutting force signal online measuring device for turning process according to claim 1, characterized in that: The voltage signal of the three-axis force obtained by the sensor signal acquisition circuit is coupled, and the size of the three-axis force is obtained by decoupling operation using a sensitivity coefficient matrix. The sensitivity coefficient matrix is ​​obtained by a uniaxial force test experiment, and the coupling relationship between the cutting force in three directions and the three-axis voltage signal is measured respectively. The three independent force signals obtained after decoupling are combined to obtain a complete force vector result.

3. The temperature signal and three-axis cutting force signal online measuring device for turning process according to claim 1, characterized in that: The differential signal amplification unit is constructed using four AD8421 instrument amplifiers, which correspond one-to-one to three cutting force signals and one temperature signal. The constant current source unit is constructed using an LM334 chip, the digital-to-analog conversion unit is constructed using an AD7606 chip, and the data sending unit is constructed using an STM32F103C8T6 microcontroller and a MAX485 chip. The differential signal amplification unit is constructed using an AD8421 instrument amplifier to map the voltage signal to an appreciable range, and the voltage analog signal is quantified using an AD7606 low-cost analog-to-digital conversion solution, and the obtained digital signal is sent to the STM32F103C8T6 microcontroller.

4. The temperature signal and three-axis cutting force signal online measuring device for turning process according to claim 1 or 3, characterized in that: The constant current source unit is a microampere-level constant excitation current output unit, which is a constant current source circuit with the LM334 power chip as the core, and uses a negative temperature coefficient silicon diode 1N457 to compensate for the temperature drift of the chip when it is working.

5. The temperature signal and three-axis cutting force signal online measuring device for turning process according to claim 3, characterized in that: The voltage signal interface is connected from the differential amplifier unit to the analog-to-digital conversion unit. The voltage signal interface receives the sensor signal from the signal pre-processing module. After passing through AD7606, the signal is quantized into a digital signal and transmitted to the microprocessor STM32F103C8T6 via SPI.

6. The temperature signal and three-axis cutting force signal online measuring device for turning process according to claim 1, characterized in that: The power input interface of the power supply circuit inputs a 10-16V DC power supply. After the input power supply +Vin passes through two voltage conversion modules, it is inverted and stepped down. The obtained positive voltage passes through a low voltage difference linear regulator and a low voltage difference linear regulator in turn and is output. The obtained negative voltage passes through a low voltage difference linear regulator and is output.

7. The device for online measuring temperature signals and three-axis cutting force signals for turning process according to claim 2, characterized in that: Output triaxial force F x 、F y 、F z The corresponding three-way voltage signal is recorded as V x 、V y 、V z , the three-axis forces are coupled, that is, the output signal V x ≠0, V y ≠0, V z ≠0, F x 、F y 、F z All V x 、V y 、V z Function of three voltage output quantities, F x =f x (V x 、V y 、V z )、F y =f y (V x 、V y 、V z )、F z =f z (V x 、V y 、V z ), f x 、f y 、f z These are three highly linear functions that can be written as F x =A1(V x -V x0 )+B1(V y -V y0 )+C1(V z -V z0 ), F y =A2(V x -V x0 )+B2(V y -V y0 )+C2(V z -V z0 ), F z =A3(V x -V x0 )+B2(V y -V y0 )+C2(V z -V z0 ); Among them, V x0 、V y0 、V z0 is the starting output value, that is, the output is cleared to zero. remember , Then F=M(V-V0), The inverse matrix of the sensitivity coefficient matrix M V-V0=M -1 F By applying uniaxial forces in the X, Y, and Z directions respectively, the three parameters corresponding to the X, Y, and Z directions can be solved respectively, so as to solve all the parameters and thus solve the sensitivity coefficient matrix M.

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