Test system and method for rapidly identifying boring rigidity coefficient

Abstract

The invention discloses a test system and method for quickly identifying a boring rigidity coefficient. The system comprises an excitation module, a force measurement module and a displacement measurement module, the vibration excitation module is composed of a first test computer, a signal generator, a power amplifier, a contact type electromagnetic vibration exciter and an air cooling air pump. The force measurement module is composed of a pressure change type force sensor, a charge amplifier, a force signal acquisition box and a first test computer. The pressure change type force sensor is installed between the workbench and a tested workpiece, the output end of the pressure change type force sensor is connected with the input end of the charge amplifier through a connecting line, the output end of the charge amplifier is connected with the input end of the force signal acquisition box through a connecting line, and the output end of the force signal acquisition box is connected with the first test computer through a USB interface; the displacement measurement module consists of an eddy current displacement sensor, a displacement signal acquisition box and a test computer II; and the three eddy current displacement sensors are respectively arranged at a measured point position of a measured workpiece end, the front end of the boring cutter and the root part of the boring cutter.

Description

Technical Field

[0001] The invention relates to the technical field of machine tool cutting, and in particular to a test system and method for quickly identifying a boring stiffness coefficient. Background Art

[0002] As the core basic equipment in the equipment manufacturing industry, the development level of machine tools is of great significance to a country's industrial strength. Machine tools are not only key tools for manufacturing various mechanical products, but also play an indispensable role in many fields such as national defense, aerospace, automobiles, electronics, and energy. As the end components of the machine tool structure, the interaction between the tool and the workpiece during the processing is one of the main sources of machine tool vibration. During the cutting process, the contact between the tool and the workpiece produces complex dynamic behavior, which directly affects the working stability and processing accuracy of the machine tool. In order to more accurately predict the cutting force, the cutting stiffness coefficient of the tool and the workpiece must be accurately identified. By accurately measuring and analyzing the cutting stiffness coefficient, more reliable data support can be provided for the cutting force model, thereby realizing the dynamic simulation and optimization of the machine tool cutting process. Accurate simulation can not only improve the processing quality and efficiency, but also effectively reduce the processing error and tool wear caused by vibration, thereby extending the service life of machine tools and tools. This is of great significance to improving the overall level and technical capabilities of the manufacturing industry.

[0003] At present, the identification method of cutting stiffness coefficient mainly conducts a large number of cutting experiments by changing cutting parameters including back cutting amount and feed rate, records the three-dimensional cutting force, and summarizes the empirical formula. The limitation of this method is that different tools need to be cut again, the experimental amount is large, and for boring, the cutting edge direction rotates around the circumference, and the cutting force direction is also constantly changing. It is impossible to measure the cutting force in each direction using only a fixed direction force measuring instrument. Summary of the invention

[0004] The purpose of the present invention is to overcome the deficiencies in the prior art and to provide a test system and method for quickly identifying the boring stiffness coefficient, so as to realize phase calibration during the boring process, overcome the problem that the cutting forces in each direction cannot be measured during the boring process, and on this basis, realize the rapid identification of the boring stiffness coefficient of any boring tool and greatly reduce the experimental workload.

[0005] The objective of the present invention is achieved through the following technical solutions:

[0006] A test system for quickly identifying boring stiffness coefficients comprises an excitation module, a force measurement module and a displacement measurement module; the excitation module comprises a test computer, a signal generator, a power amplifier, a contact electromagnetic vibrator and an air-cooled air pump; the test computer is connected to the signal generator via a USB interface, the output end of the signal generator is connected to the input end of the power amplifier via a connecting line, the output end of the power amplifier is connected to the signal input end of the contact electromagnetic vibrator via a connecting line, and the air-cooled air pump is connected to the cooling port of the contact electromagnetic vibrator via a hose;

[0007] The force measurement module is composed of a pressure-variable force sensor, a charge amplifier, a force signal acquisition box and a test computer. The pressure-variable force sensor is installed between the workbench and the workpiece to be measured, the output end of the pressure-variable force sensor is connected to the input end of the charge amplifier through a connecting line, the output end of the charge amplifier is connected to the input end of the force signal acquisition box through a connecting line, and the output end of the force signal acquisition box is connected to the test computer through a USB interface.

[0008] The displacement measurement module consists of an eddy current displacement sensor, a displacement signal acquisition box and a test computer 2; the three eddy current displacement sensors are respectively installed at the measured point at the end of the workpiece, the front end of the boring tool and the root of the boring tool, and are connected to the displacement signal acquisition box equipped with an NI acquisition card through connecting lines, and the output end of the displacement signal acquisition box is connected to the test computer 2 through a USB interface.

[0009] Furthermore, before the experiment, a 0.5mm thick thin iron sheet with a length of 5mm and a width of 2mm was pasted on the root of the boring cutter. Its position on the circumference of the boring cutter was consistent with that of the boring blade. The eddy current displacement sensors located at the measured point at the end of the workpiece and the front end of the boring cutter were used to measure the vibration displacement of the measured point at the end of the workpiece and the front end of the boring cutter, respectively. The eddy current displacement sensor at the root of the boring cutter was aligned with the thin iron sheet to record the phase during the rotation of the boring cutter.

[0010] The present invention also provides a method for quickly identifying the boring stiffness coefficient. The test system based on the above-mentioned quick identification of the boring stiffness coefficient includes:

[0011] Step 1: According to the metal cutting theory, a dynamic cutting force model is established from the perspective of cutting area and cutting line length. The cutting stiffness coefficient includes the radial, tangential and axial cutting stiffness coefficients of the cutting area and the radial, tangential and axial cutting stiffness coefficients of the cutting line length.

[0012] Step 2: According to the dynamic cutting force model, the dynamic cutting force is analyzed by changing the cutting parameters, and the ratio of the dynamic cutting force to the change in the back cutting amount is linearly related to the feed rate, and the ratio of the dynamic cutting force to the change in the back cutting amount is expressed as a function of the feed rate; the cutting parameters include the back cutting amount and the feed rate;

[0013] Step 3: The signal generator generates a stable sinusoidal excitation digital signal with a frequency of 160 Hz, which is converted into an analog sinusoidal signal by a built-in digital-to-analog converter. The analog sinusoidal signal is amplified by a power amplifier and input to the input end of the contact electromagnetic exciter; the frequency is the natural frequency of the workpiece to be measured after it is installed in the cutting position;

[0014] Step 4: The contact electromagnetic vibrator drives the internal connecting rod to vibrate according to the input analog sinusoidal signal. The connecting rod is connected to the workpiece to be measured through a thread. The vibration of the connecting rod drives the workpiece to be measured to vibrate. The boring stiffness coefficient is identified by converting the back cutting amount under steady-state cutting into the back cutting amount under dynamic cutting during the cutting process.

[0015] Step 5, using a pressure-variable force sensor to record the force on the workpiece during the experiment, and using three eddy current displacement sensors to record the measured point position at the end of the workpiece, the vibration displacement at the front end of the boring tool, and the rotation phase of the boring tool;

[0016] Step six, through the boring cutter rotation phase, extract the vibration displacement data of the same phase part at different times and combine it with the corresponding force signal data, calculate the relationship between vibration displacement and cutting force under different cutting conditions, and calculate the boring stiffness coefficient through linear regression.

[0017] Furthermore, the influence of cutting area and cutting line length on dynamic cutting force in step 1 is expressed as the following formula;

[0018]

[0019] Where A is the cutting area, L is the cutting line length, dF t 、dF r 、dF a are the radial, tangential and axial cutting force components, respectively, k At , k Ar , k Aa are the radial, tangential and axial cutting stiffness coefficients of the cutting area, k Lt , k Lr , k La are the cutting stiffness coefficients in the radial, tangential and axial directions of the cutting line length respectively;

[0020] The simple harmonic vibration of the workpiece under test is expressed as follows:

[0021] x1=A1 sin(ω1t)

[0022] A1 is the vibration amplitude of the workpiece being measured, ω1 is the vibration angular velocity of the workpiece being measured;

[0023] The vibration of the boring tool in the exciting direction is recorded as:

[0024]

[0025] A2 is the vibration amplitude of the boring tool, ω2 is the vibration angular velocity of the boring tool, is the phase difference between the vibration of the workpiece being measured and the vibration of the boring tool;

[0026] The relative displacement of the boring tool and the workpiece is expressed as:

[0027]

[0028] Furthermore, since the boring tool is constantly rotating during the boring process, when the simple harmonic vibration direction of the workpiece is in line with the cutting direction of the machine tool,

[0029] When vertical, the cutting depth f is expressed as:

[0030]

[0031] f' is the depth of cut under steady-state cutting;

[0032] The change in back cutting amount is expressed as:

[0033]

[0034] The cutting area and cutting line length are expressed as:

[0035]

[0036] s is the feed per revolution, κ r is the main deflection angle;

[0037] The change in cutting area is expressed as:

[0038]

[0039] Cutting line length variation:

[0040]

[0041] The dynamic cutting force model is expressed as:

[0042]

[0043] Furthermore, the testing process in step 5 is divided into three parts:

[0044] The first is the idling stage of the machine tool spindle. During this stage, no cutting is performed and the exciter is not turned on, so that the machine tool bottom noise can be recorded through the eddy current displacement sensor.

[0045] The second stage is when the machine tool spindle is idling and the exciter is turned on. In this stage, the magnitude and phase of the exciting force and the magnitude and phase of the displacement vibration of the workpiece are recorded through the pressure variable force sensor and the eddy current displacement sensor.

[0046] Finally, the workpiece under test is cut while being excited, and the cutting force signal, vibration signal of the workpiece under test and boring tool and phase record are recorded.

[0047] The present invention also provides an electronic device, comprising a memory, a processor and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of a method for rapidly identifying a boring stiffness coefficient when executing the program.

[0048] The present invention also provides a computer-readable storage medium on which a computer program is stored, characterized in that when the computer program is executed by a processor, the steps of the method for quickly identifying the boring stiffness coefficient are implemented.

[0049] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0050] 1. Improved experimental efficiency: The traditional method requires multiple changes in cutting parameters and a large number of experiments. The present invention introduces a dynamic back-cut cutting method to significantly reduce the number of experimental groups and workload, achieve rapid identification of the boring stiffness coefficient, and save time and resources.

[0051] 2. Accurate identification of cutting stiffness coefficient: The present invention constructs a dynamic cutting force model based on metal cutting theory, combines the influence of cutting area and cutting line length on cutting force, and accurately identifies radial, tangential and axial cutting stiffness coefficients through variable feed rate experiments, ensuring data reliability and accuracy, and providing higher accuracy for cutting force prediction.

[0052] 3. Dynamic cutting condition simulation: The system simulates the dynamic cutting condition of back cutting through sinusoidal excitation force, and expands the steady-state conditions to dynamic conditions, so as to accurately analyze the dynamic behavior in the complex cutting process, which helps to improve the design and optimization of cutting parameters and improve the quality and efficiency of machine tool processing.

[0053] 4. Multi-directional cutting force measurement: The test system is designed with the function of recording the tool rotation angle. By combining multiple sensors to measure the workpiece force and tool displacement, it can accurately measure the cutting force in each direction when the cutting edge direction rotates around the circle and the cutting force direction is constantly changing. This solves the problem that the cutting force direction cannot be accurately measured as the tool rotates, thereby achieving high-precision identification of the cutting stiffness coefficient of each cutting force.

[0054] 5. Vibration error control: By accurately obtaining the dynamic stiffness characteristics of the tool-workpiece contact area, the present invention can effectively reduce the machining errors caused by vibration, improve machining stability and surface quality, and extend the service life of the machine tool and tool.

[0055] 6. Wide range of applications: The test system of the present invention is applicable to various boring tools and workpieces, can be quickly adapted to different processing scenarios, has wide practicality and promotion value, and is of great significance to improving processing accuracy and reducing costs in the manufacturing industry.

[0056] In summary, the present invention achieves accurate analysis of complex boring dynamic behavior while significantly reducing the amount of experiments, providing strong support for cutting process optimization and manufacturing technology advancement. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Figure 1 It is a structural schematic diagram of the test system of the present invention.

[0058] Figure 2 It is a schematic diagram of the process of the present invention.

[0059] Figure 3 Schematic diagram of the cutting process.

[0060] Figures 4a to 4c The cutting force test and simulation results in the x, y and z directions under variable feed rate conditions are shown respectively. DETAILED DESCRIPTION

[0061] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0062] like Figure 1 As shown, this embodiment provides a test system for quickly identifying the boring stiffness coefficient, including an excitation module, a force measurement module, and a displacement measurement module; the excitation module is composed of a test computer, a signal generator, a power amplifier, an exciter, and an air-cooled air pump. The exciter adopts a contact electromagnetic exciter, the test computer is connected to the signal generator through a USB interface, the output interface of the signal generator is connected to the input end of the power amplifier through a connecting line, the output end of the power amplifier is connected to the signal input end of the contact electromagnetic exciter through a connecting line, and the air-cooled air pump is connected to the cooling port of the contact electromagnetic exciter through a hose;

[0063] The power amplifier amplifies the weak sinusoidal signal generated by the signal generator to drive the contact electromagnetic exciter. The air-cooling air pump pumps air into the coil of the contact electromagnetic exciter to cool the electromagnetic coil and prevent the coil from overheating and damage.

[0064] The force measurement module consists of a pressure-variable force sensor, a charge amplifier, a force signal acquisition box, and a test computer. The pressure-variable force sensor is installed between the workbench and the workpiece to be measured, and can accurately measure the three-dimensional force of the workpiece. The output end of the pressure-variable force sensor is connected to the input end of the charge amplifier through a connecting line, and the output end of the charge amplifier is connected to the input end of the force signal acquisition box through a connecting line. The output end of the force signal acquisition box is connected to the test computer through a USB interface.

[0065] The displacement measurement module consists of an eddy current displacement sensor, a displacement signal acquisition box and a test computer 2. The three eddy current displacement sensors are installed at the measured point on the workpiece end, the front end of the boring tool and the root of the boring tool, respectively, and are connected to the displacement signal acquisition box installed with an NI acquisition card through a connecting line. The output end of the displacement signal acquisition box is connected to the test computer 2 through a USB interface;

[0066] Before the experiment, a 0.5mm thick thin iron sheet with a length of 5mm and a width of 2mm was pasted on the root of the boring tool. Its position on the circumference of the boring tool was consistent with that of the boring blade. Three eddy current displacement sensors were installed at the measured point on the workpiece end, the front end of the boring tool and the root of the boring tool. The purpose of the first two is to measure the vibration displacement of the measured point on the workpiece end and the front end of the boring tool, and the latter is aimed at the thin iron sheet to record the phase through displacement data during the rotation of the boring tool.

[0067] Preferably, this embodiment also provides a method for quickly identifying boring stiffness coefficient, comprising:

[0068] Step 1: According to the metal cutting theory, a dynamic cutting force model is established from the perspective of cutting area and cutting line length. The cutting stiffness coefficient includes the radial, tangential and axial cutting stiffness coefficients of the cutting area and the radial, tangential and axial cutting stiffness coefficients of the cutting line length.

[0069] According to the dynamic cutting force model, by changing the cutting parameters to analyze the dynamic cutting force, it can be found that the ratio of the dynamic cutting force to the change in the back cutting amount is linearly related to the feed rate, and the ratio of the dynamic cutting force to the change in the back cutting amount is expressed as a function of the feed rate; the cutting parameters include the back cutting amount and the feed rate;

[0070]

[0071] In the formula, k At , k Ar , k Aa are the radial, tangential and axial cutting stiffness coefficients of the cutting area, k Lt , k Lr , k La are the radial, tangential and axial cutting stiffness coefficients of the cutting line length respectively; s is the feed per revolution, κ rThe experimental conditions of each group of cutting experiments are that the back cutting amount remains unchanged without excitation, the spindle speed remains unchanged, and only the feed speed is changed.

[0072] Step 2. Before the experiment, adjust the three eddy current sensors to the appropriate measuring distance and align them with the radial position of the boring tool. Set the acquisition frequency of the force measurement module and the displacement measurement module to the same value and try to take the maximum value. Turn on the pressure-variable force sensor and eddy current displacement sensor for synchronous recording.

[0073] Start the spindle under the conditions of step 2. This is the idling stage of the machine tool spindle. No cutting is performed and the exciter is not turned on in this stage. The purpose is to record the machine tool background noise through the displacement sensor. Then start moving the worktable at a certain feed speed to record the vibration caused by the machine tool feed system.

[0074] Step 3: Turn on the air cooling pump of the excitation module and pump air into the coil of the contact electromagnetic exciter to ensure good heat dissipation of the exciter. The signal generator generates a stable sinusoidal excitation digital signal with a frequency of 160 Hz, which is converted into an analog sinusoidal signal by the built-in digital-to-analog converter. The analog sinusoidal signal is amplified by the power amplifier and input to the input end of the contact electromagnetic exciter. The frequency is the natural frequency of the workpiece after it is installed in the cutting position.

[0075] The contact electromagnetic vibrator drives the internal connecting rod to vibrate according to the input sinusoidal signal. The connecting rod is connected to the workpiece to be measured through a thread. The vibration of the connecting rod drives the workpiece to be measured to vibrate. During the cutting process, the back cutting amount under steady-state cutting is converted into the back cutting amount under dynamic cutting.

[0076] Step 4: Use a pressure-variable force sensor to record the force on the workpiece during the experiment, and use three eddy current displacement sensors to record the measured point position at the end of the workpiece, the vibration displacement at the front end of the boring tool, and the rotation phase of the boring tool;

[0077] The test process is divided into three parts. The first is the idling stage of the machine tool spindle. In this stage, no cutting is done and the exciter is not turned on. The purpose is to record the machine tool bottom noise through the displacement sensor. The second stage is the idling of the machine tool spindle and the exciter is turned on at the same time. In this stage, the magnitude and phase of the exciting force and displacement vibration of the workpiece are recorded through the pressure variable force sensor and eddy current displacement sensor. The third stage is to cut while exciting, record the cutting force signal, the vibration signal of the workpiece and the tool, and the phase record.

[0078] Step five, dynamic cutting experiments were carried out with a fixed back cutting depth of 0.1 mm, a cutting speed of 240 mm / min, and feed speeds of eight groups of 0.02 mm / r, 0.04 mm / r, 0.06 mm / r, 0.08 mm / r, 0.1 mm / r, 0.12 mm / r, 0.14 mm / r, and 0.16 mm / r.

[0079] Step six, experimental data processing, first according to the phase signal, intercept the data of the tool cutting direction and the vertical stage of the excitation direction, including the three-dimensional cutting force signals of the X-axis, Y-axis, and Z-axis and the vibration displacement signals of the workpiece and the tool. According to the machine tool background noise recorded during the idling stage of the machine tool spindle, Fourier filtering is used to retain the signals in the excitation frequency band and filter out other interference signals.

[0080] Step seven, after obtaining the filtered signal, use the least squares method to fit the three-dimensional exciting force and vibration displacement of the workpiece when the machine tool is not started and only under the action of the exciter, according to the data segment when the machine tool spindle is idling and the exciter is turned on. Fit it into a sinusoidal signal, and record the amplitude of the exciting force, the amplitude of the vibration displacement, and the phase difference between the two.

[0081] According to the data of the excitation and cutting stage, the change of cutting force caused by dynamic cutting is fitted based on the three-dimensional excitation force signal fitted in the uncut section, and the three-dimensional cutting force is fitted into a sine signal, and the amplitude of the cutting force is recorded. Similarly, based on the workpiece vibration displacement signal fitted in the uncut section, the change of workpiece tool vibration displacement caused by dynamic cutting is fitted, and the change of workpiece tool vibration displacement is fitted into a sine signal, and the amplitude of workpiece tool vibration displacement is recorded.

[0082] Step 8: Calculate the cutting stiffness under the working condition by calculating the amplitude ratio between the dynamic cutting force signal and the tool-workpiece displacement. Take the cutting stiffness of four points in the same working condition and take the average value as the cutting stiffness under the working condition. Calculate the cutting stiffness of each group, substitute it into the dynamic cutting force formula, and obtain the cutting force stiffness coefficients in three directions. Figure 4a , Figure 4b and Figure 4c As shown, the experimental cutting force based on the above method is consistent with the simulation results of the boring stiffness coefficient cutting force model, which provides a method for quickly identifying the boring stiffness coefficient.

[0083] Preferably, the embodiments of the present application also provide a specific implementation of an electronic device capable of implementing all steps in the method for quickly identifying the boring stiffness coefficient in the above embodiment, and the electronic device specifically includes the following contents:

[0084] Processor, memory, communications interface and bus;

[0085] Among them, the processor, memory, and communication interface communicate with each other through the bus; the communication interface is used to realize information transmission between related devices such as server-side devices, metering devices, and user-side devices.

[0086] The processor is used to call the computer program in the memory, and when the processor executes the computer program, all the steps in the method for quickly identifying the boring stiffness coefficient in the above embodiment are implemented.

[0087] An embodiment of the present application also provides a computer-readable storage medium capable of implementing all the steps of the method for quickly identifying the boring stiffness coefficient in the above embodiment. The computer-readable storage medium stores a computer program, which, when executed by a processor, implements all the steps of the method for quickly identifying the boring stiffness coefficient in the above embodiment.

[0088] The above is a description of a specific embodiment of the specification. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recorded in the claims can be performed in an order different from that in the embodiments and still achieve the desired results. In addition, the processes depicted in the drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0089] Although the present application provides method operation steps such as embodiments or flow charts, more or fewer operation steps may be included based on conventional or non-creative labor. The order of steps listed in the embodiments is only one way of executing the order of many steps and does not represent the only execution order. When the actual device or client product is executed, it can be executed in the order of the method shown in the embodiments or the drawings or in parallel (for example, in a parallel processor or multi-threaded processing environment).

[0090] Those skilled in the art will appreciate that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0091] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0092] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0093] The present invention is not limited to the embodiments described above. The above description of the specific embodiments is intended to describe and illustrate the technical solution of the present invention. The above specific embodiments are merely illustrative and not restrictive. Without departing from the scope of the present invention and the scope of protection of the claims, a person of ordinary skill in the art can also make many forms of specific changes under the guidance of the present invention, which all fall within the scope of protection of the present invention.

Claims

1. A test system for quickly identifying boring stiffness coefficient, characterized in that: It includes an excitation module, a force measurement module, and a displacement measurement module; the excitation module is composed of a test computer, a signal generator, a power amplifier, a contact electromagnetic vibrator, and an air-cooled air pump; the test computer is connected to the signal generator through a USB interface, the output end of the signal generator is connected to the input end of the power amplifier through a connecting line, the output end of the power amplifier is connected to the signal input end of the contact electromagnetic vibrator through a connecting line, and the air-cooled air pump is connected to the cooling port of the contact electromagnetic vibrator through a hose; The force measurement module is composed of a pressure-variable force sensor, a charge amplifier, a force signal acquisition box and a test computer. The pressure-variable force sensor is installed between the workbench and the workpiece to be measured, the output end of the pressure-variable force sensor is connected to the input end of the charge amplifier through a connecting line, the output end of the charge amplifier is connected to the input end of the force signal acquisition box through a connecting line, and the output end of the force signal acquisition box is connected to the test computer through a USB interface. The displacement measurement module consists of an eddy current displacement sensor, a displacement signal acquisition box and a test computer 2; the three eddy current displacement sensors are respectively installed at the measured point at the end of the workpiece, the front end of the boring tool and the root of the boring tool, and are connected to the displacement signal acquisition box equipped with an NI acquisition card through connecting lines, and the output end of the displacement signal acquisition box is connected to the test computer 2 through a USB interface.

2. A test system for quickly identifying boring stiffness coefficient according to claim 1, characterized in that: Before the experiment, a 0.5mm thick thin iron sheet with a length of 5mm and a width of 2mm was pasted on the root of the boring tool. Its position on the circumference of the boring tool was consistent with that of the boring blade. The eddy current displacement sensors located at the measured point at the end of the workpiece and the front end of the boring tool were used to measure the vibration displacement of the measured point at the end of the workpiece and the front end of the boring tool, respectively. The eddy current displacement sensor at the root of the boring tool was aligned with the thin iron sheet to record the phase during the rotation of the boring tool.

3. A method for quickly identifying boring stiffness coefficient, based on the test system for quickly identifying boring stiffness coefficient according to any one of claims 1-2, characterized in that: include: Step 1: According to the metal cutting theory, a dynamic cutting force model is established from the perspective of cutting area and cutting line length. The cutting stiffness coefficient includes the radial, tangential and axial cutting stiffness coefficients of the cutting area and the radial, tangential and axial cutting stiffness coefficients of the cutting line length. Step 2: According to the dynamic cutting force model, the dynamic cutting force is analyzed by changing the cutting parameters, and the ratio of the dynamic cutting force to the change in the back cutting amount is linearly related to the feed rate, and the ratio of the dynamic cutting force to the change in the back cutting amount is expressed as a function of the feed rate; the cutting parameters include the back cutting amount and the feed rate; Step 3: The signal generator generates a stable sinusoidal excitation digital signal with a frequency of 160 Hz, which is converted into an analog sinusoidal signal by a built-in digital-to-analog converter. The analog sinusoidal signal is amplified by a power amplifier and input to the input end of the contact electromagnetic exciter; the frequency is the natural frequency of the workpiece to be measured after it is installed in the cutting position; Step 4: The contact electromagnetic vibrator drives the internal connecting rod to vibrate according to the input analog sinusoidal signal. The connecting rod is connected to the workpiece to be measured through a thread. The vibration of the connecting rod drives the workpiece to be measured to vibrate. The boring stiffness coefficient is identified by converting the back cutting amount under steady-state cutting into the back cutting amount under dynamic cutting during the cutting process. Step 5, using a pressure-variable force sensor to record the force on the workpiece during the experiment, and using three eddy current displacement sensors to record the measured point position at the end of the workpiece, the vibration displacement at the front end of the boring tool, and the rotation phase of the boring tool; Step six, through the boring cutter rotation phase, extract the vibration displacement data of the same phase part at different times and combine it with the corresponding force signal data, calculate the relationship between vibration displacement and cutting force under different cutting conditions, and calculate the boring stiffness coefficient through linear regression.

4. A method for quickly identifying boring stiffness coefficient according to claim 3, characterized in that: The influence of cutting area and cutting line length on dynamic cutting force in step 1 is expressed as follows: Where A is the cutting area, L is the cutting line length, dF t 、dF r 、dF a are the radial, tangential and axial cutting force components, respectively, k At , k Ar , k Aa are the radial, tangential and axial cutting stiffness coefficients of the cutting area, k Lt , k Lr , k La are the cutting stiffness coefficients in the radial, tangential and axial directions of the cutting line length respectively; By applying an external excitation force to the workpiece, the workpiece undergoes simple harmonic vibration, which can be expressed as: x1=A1 sin(ω1t) A1 is the vibration amplitude of the workpiece being measured, ω1 is the vibration angular velocity of the workpiece being measured; The vibration of the boring tool in the exciting direction is recorded as: A2 is the vibration amplitude of the boring tool, ω2 is the vibration angular velocity of the boring tool, is the phase difference between the vibration of the workpiece being measured and the vibration of the boring tool; The relative displacement of the boring tool and the workpiece is expressed as: Furthermore, since the boring tool is constantly rotating during the boring process, when the simple harmonic vibration direction of the workpiece is perpendicular to the cutting direction of the machine tool, the cutting depth f is expressed as: f' is the depth of cut under steady-state cutting; The change in back cutting amount is expressed as: The cutting area and cutting line length are expressed as: s is the feed per revolution, κ r is the main deflection angle; The change in cutting area is expressed as: Cutting line length variation: The dynamic cutting force model is expressed as:

5. A method for quickly identifying boring stiffness coefficient according to claim 3, characterized in that: The testing process in step 5 is divided into three parts: The first is the idling stage of the machine tool spindle. During this stage, no cutting is performed and the exciter is not turned on, so that the machine tool bottom noise can be recorded through the eddy current displacement sensor. The second stage is when the machine tool spindle is idling and the vibration exciter is turned on. In this stage, the magnitude and phase of the exciting force and the magnitude and phase of the displacement vibration of the workpiece are recorded through the pressure variable force sensor and the eddy current displacement sensor. Finally, the workpiece under test is cut while being excited, and the cutting force signal, vibration signal of the workpiece under test and boring tool and phase record are recorded.

6. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the program, the steps of the method for quickly identifying the boring stiffness coefficient according to any one of claims 3 to 5 are implemented.

7. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method for quickly identifying boring stiffness coefficient described in any one of claims 3 to 5 are implemented.

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