An embedded flexible sensor turning force measuring tool and machine tool

Abstract

The application belongs to the field of cutting tools, and provides a turning force measuring tool with embedded flexible sensors and a machine tool, which effectively measures the turning force without affecting the structure of the turning process, and ensures the accuracy and reliability of the signal, and the technical scheme comprises a tool body, the tool body comprises a blade, a positioning assembly and a clamping assembly for clamping the blade; the positioning assembly comprises a freedom degree limiting assembly for limiting the movement of the blade along the x-axis, y-axis and z-axis directions; a flexible sensor is arranged on the lower surface of the blade, a flexible circuit is arranged at the front end of the tool body, the pressure sensor and the flexible circuit are connected through flexible wires; the flexible sensor is used for converting the deformation of the blade under the action of the turning force into a voltage signal; and the flexible circuit is used for calculating the size of the turning force according to the relationship between the voltage signal and the turning force.

Description

Technical Field

[0001] This invention belongs to the field of cutting tools, and particularly relates to an embedded turning force flexibility measuring device and tool system. Background Technology

[0002] The statements in this section are merely background information related to the present invention and do not necessarily constitute prior art.

[0003] First, turning force is one of the main factors affecting the accuracy of metal turning. Real-time measurement of turning force allows for timely adjustment of turning parameters and optimization of the turning process, thereby ensuring machining quality and extending tool life. Second, measuring turning force helps monitor various states during the cutting process, such as tool wear, workpiece material changes, and turning process abnormalities, thus ensuring production efficiency and machining quality. Furthermore, sensors can monitor changes in turning force in real time and feed them back to the CNC system, enabling the system to dynamically adjust feed rate and other process parameters to improve machining efficiency and stability. Therefore, using sensors to measure turning force in turning operations is essential for improving machining accuracy, efficiency, and reliability.

[0004] Current turning force testing devices mainly use piezoelectric triaxial force testers. Existing turning force measurement systems, such as tool holder-type turning force testers, need to be installed on the machine tool tool holder, which affects the turning machining structure. At the same time, the original machining equipment needs to be modified, making the installation process relatively complicated. Piezoelectric triaxial cutting force testing systems are lacking in dynamic response, ease of installation, and data processing efficiency. In addition, most cutting force testing does not involve feedback control schemes, and cannot dynamically adjust the spindle speed and feed rate simultaneously based on the deviation between the real-time cutting force and the set value. Summary of the Invention

[0005] To address at least one of the technical problems in the background art described above, the first aspect of the present invention provides an embedded flexible sensor for measuring turning force, which effectively measures the turning force without affecting the turning machining structure, while ensuring the accuracy and reliability of the signal.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] An embedded flexible sensor for measuring turning force in a cutting tool includes a tool body, which includes a cutting insert, a positioning assembly, and a clamping assembly for clamping the cutting insert. The positioning assembly includes a degree-of-freedom limiting assembly for restricting the movement of the cutting insert along the x-axis, y-axis, and z-axis. A flexible sensor is disposed on the lower surface of the cutting insert, and a flexible circuit is disposed at the front end of the tool body. The flexible sensor and the flexible circuit are connected by a flexible wire.

[0008] The flexible sensor is used to convert the deformation of the cutting tool under turning force into a voltage signal;

[0009] The flexible circuit is used to calculate the magnitude of the turning force based on the mapping relationship between the voltage signal and the turning force.

[0010] Furthermore, the positioning component includes a washer, a short cylindrical pin, and a chamfered pin. Two connected grooves are formed on the cutter body. The washer and the blade are stacked sequentially on the upper surface of the first groove, and the washer is placed under the blade. The first groove is provided with a first through hole and a second through hole. The short cylindrical pin is provided in the first through hole, and the chamfered pin is provided in the second through hole. One end of the short cylindrical pin and the chamfered pin passes through the cutter body, and the other end passes through the washer into the blade.

[0011] Furthermore, the clamping assembly includes a wedge, a round-headed screw, a spring washer, a bolt, and a stop; a spring washer and a wedge are provided on the upper surface of the second groove in the y direction of the blade, the second groove is provided with a third through hole, and a round-headed screw is provided in the third through hole. One end of the round-headed screw passes through the blade body, and the other end passes through the wedge through the spring washer; a bolt and a stop are provided on the side of the first groove in the x direction of the blade, the bolt and the stop are threadedly connected, and the stop is pushed into the blind hole by the threaded fastening screw of the blade body in the x direction.

[0012] Furthermore, the flexible sensor includes a first encapsulation layer, a base layer, a sensitive layer, a conductive layer, and a second encapsulation layer; the first encapsulation layer, the base layer, the sensitive layer, the conductive layer, and the second encapsulation layer are bonded together sequentially from bottom to top; the first encapsulation layer is bonded to a gasket, and the bonded sensitive layer and conductive layer form the main body of the sensor used to convert the turning force into an electrical signal; the second encapsulation layer is located on the outermost layer of the sensor and is in direct contact with the cutting blade.

[0013] Furthermore, the sensitive layer includes a substrate, symmetrically distributed resistor grids and electrodes disposed on the substrate; the symmetrically distributed resistor grids include a first resistor R1 and a second resistor R2 parallel to the radial direction of the blade, and a third resistor R3 and a fourth resistor R4 perpendicular to the radial direction of the blade; the first resistor R1, the second resistor R2, the third resistor R3 and the fourth resistor R4 are connected to an external voltage through electrodes to form a Wheatstone bridge, and the output terminal of the Wheatstone bridge is connected to the input terminal of the flexible circuit.

[0014] Furthermore, the flexible circuit module includes a flexible circuit board, a wireless communication module and a control module disposed on the flexible circuit board. The control module includes a signal amplification circuit, an A / D conversion circuit and a microprocessor. One end of the signal amplification circuit is connected to the flexible sensor and the other end is connected to the input terminal of the A / D conversion circuit. The output terminal of the A / D conversion circuit is connected to the microprocessor module. The microprocessor module is used to calculate the magnitude of the turning force based on the relationship between the electrical signal and the turning force.

[0015] Furthermore, the mapping relationship between the voltage signal and the turning force is as follows:

[0016]

[0017]

[0018] Where F is the cutting force, σ is the stress, GF is the strain gauge sensitivity coefficient, E is the elastic modulus of the tool material, A is the cross-sectional area of ​​the strain gauge's sensitive region, U0 is the output voltage of the Wheatstone bridge, and U ab U is the voltage of line ab at R3. bc U1 is the voltage of line bc at R2, U1 is the external power supply voltage, I1 is the current of the series circuit of R1 and R3, and I2 is the current of the series circuit of R2 and R4.

[0019] To address the aforementioned problems, a second aspect of the present invention provides an embedded flexible sensor for measuring turning force, which effectively measures the turning force without affecting the turning machining structure, while ensuring the accuracy and reliability of the signal.

[0020] The positioning component is replaced with a tapered lever pin, a chamfering pin, and a washer. A V-shaped groove is formed on the cutter body. A washer and a blade are stacked sequentially on the upper surface of the V-shaped groove, and the washer is placed under the blade. The V-shaped groove is provided with a first through hole and a second through hole. A tapered lever pin is provided in the first through hole, and a chamfering pin is provided in the second through hole. One end of the tapered lever pin and the chamfering pin passes through the cutter body, and the other end passes through the washer into the blade.

[0021] The clamping assembly is replaced by a pressure plate, a slotted conical end clamping screw, and a conical lever pin. The conical lever pin is provided in the y-direction of the blade. A third through hole is provided in the blade body, and a slotted conical end clamping screw is provided in the third through hole. The top of the slotted conical end clamping screw reaches the tail end of the conical lever pin, so that the diamond-shaped blade is stuck in the V-groove of the blade body. A pressure plate is provided in the z-direction of the blade.

[0022] To address the aforementioned problems, a third aspect of the present invention provides an embedded flexible sensor turning force measuring machine tool, which effectively measures the turning force without affecting the turning process structure, while ensuring the accuracy and reliability of the signal.

[0023] To achieve the above objectives, the present invention adopts the following technical solution:

[0024] An embedded flexible sensor turning force measuring machine tool includes a machine bed, one end of which is equipped with a bracket and a headstock, and the other end is fixed with a tailstock. The bracket is provided with a chuck for holding a workpiece. A feed module is provided between the headstock and the tailstock, and the feed module is equipped with an embedded flexible sensor turning force measuring tool as described in the first or second aspect.

[0025] The beneficial effects of this invention are:

[0026] 1. This invention can measure the turning force of cutting tools of different shapes and sizes without damaging the original turning structure. A flexible sensor is set on the lower surface of the cutting tool to convert the deformation of the cutting tool under the action of turning force into an electrical signal. This improves the fit of the cutting tool during the turning process. The magnitude of the turning force is calculated based on the relationship between the electrical signal and the turning force, which can more accurately capture the changes in the cutting force of the cutting tool during the turning process. This avoids interference and damage to the turning structure and achieves more accurate measurement of the turning force.

[0027] 2. This invention utilizes a flexible material for the conductive wires, which possesses excellent flexibility and lightweight properties, facilitating installation and bending applications. Simultaneously, through-holes are created inside the blade pads, preventing excessive bending of the wires during use, thus extending wire lifespan and significantly improving the safety factor of the data acquisition system.

[0028] 3. This invention provides a flexible sensor grinding heat measurement fixture device that transmits data wirelessly via WiFi, replacing the traditional wired connection, avoiding the need for complex wiring on site, thereby reducing environmental modification costs and facilitating the work of data collection personnel.

[0029] Advantages of additional aspects of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0030] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0031] Figure 1 This is a schematic diagram of the embedded flexible sensor turning force measuring tool structure of Embodiment 1 of the present invention;

[0032] Figure 2 This is a schematic diagram of the six-point positioning of the blade in Embodiment 1 of the present invention;

[0033] Figure 3 This is a layered structure diagram of the flexible piezoresistive sensor according to Embodiment 1 of the present invention;

[0034] Figure 4 This is a structural diagram of the sensitive layer of the flexible sensor according to Embodiment 1 of the present invention;

[0035] Figure 5 This is a structural diagram of the flexible circuit system according to Embodiment 1 of the present invention;

[0036] Figure 6 This is a structural diagram of the turning force data acquisition in Embodiment 1 of the present invention;

[0037] Figure 7 This is a structural diagram of the turning force data acquisition in Embodiment 1 of the present invention;

[0038] Figure 8 This is a circuit diagram of the flexible piezoresistive sensor according to Embodiment 1 of the present invention;

[0039] Figure 9 This is a circuit diagram of the flexible sensor electronic interface of Embodiment 1 of the present invention;

[0040] Figure 10 This is a schematic diagram of the power supply circuit of Embodiment 1 of the present invention;

[0041] Figure 11 This is a signal conditioning circuit diagram of Embodiment 1 of the present invention;

[0042] Figure 12 This is a flowchart of Bluetooth data transmission according to Embodiment 1 of the present invention;

[0043] Figure 13 This is a flowchart of the lower-level machine in Embodiment 1 of the present invention;

[0044] Figure 14 This is a flowchart of the system software feedback control in Embodiment 1 of the present invention;

[0045] Figure 15 This is a framework diagram of the cutting monitoring closed-loop feedback control system of Embodiment 1 of the present invention;

[0046] Figure 16 This is the flexible measurement system device for the lever-type cutting tool in Embodiment 2 of the present invention;

[0047] Figure 17 This is a schematic diagram of the six-point positioning of the blade in the lever-pin structure of Embodiment 2 of the present invention;

[0048] Figure 18 This is a schematic diagram of the flexible turning force measuring machine tool device according to Embodiment 3 of the present invention;

[0049] Figure 19 This is a flowchart of the turning system of Embodiment 3 of the present invention;

[0050] The components include: 1. First blade body; 2. Groove; 201. First groove; 2011. First through hole; 2012. Second through hole; 202. Second groove; 2021. Third through hole; 3. Round head screw; 4. Spring washer; 5. First chamfered pin; 6. First blade; 7. Short cylindrical pin; 8. Flexible sensor; 801. First encapsulation layer; 802. Base layer; 803. Sensitive layer; 8031. Base; 8032. Electrode; 8033. Resistor grid; 804. Conductive layer; 805. Second encapsulation layer; 9. First gasket; 10. Flexible wire; 11. Flexible circuit module; 1101. Circuit board; 1102. Power module; 1103. Wireless communication module; 1104. Control module; 12. Bolt; 13. Stop. 14. Wedge block; 15. Second cutter body; 16. Second cutting tool; 17. Tapered lever pin; 18. Second chamfer pin; 19. Second washer; 20. Third through hole; 21. Fourth through hole; 22. Spring ring; 23. Pressure plate; 24. Slotted tapered end tightening screw; 25. Fifth through hole; 26. Pressure plate; 27. Hexagonal screw; 28. Bed; 29. ​​Bracket; 30. Tailstock; 31. Spindle; 32. Drive motor; 33. Chuck; 34. Headstock; 35. Lead screw; 36. Feed axis; 37. Sliding block; 38. First slide box; 39. Second slide box; 40. Threaded rod; 41. Tool post; 42. Second sliding handle; 43. First sliding handle; 44. First gear; 45. Second gear; 46. Toothed belt; 47. Fixing plate. Detailed Implementation

[0051] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0052] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0053] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0054] In this invention, terms such as "connected" and "linked" should be interpreted broadly, indicating a fixed connection, an integral connection, or a detachable connection; a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can determine the specific meaning of these terms in this invention based on the specific circumstances, and they should not be construed as limitations on the invention.

[0055] To address the issue that traditional turning force measurement tool devices affect the accuracy of measurement results due to the influence of the turning machining structure, this invention proposes a turning force measurement tool device with a flexible sensor. The device includes a tool body, which comprises an insert, a positioning assembly, and a clamping assembly for clamping the insert. The positioning assembly includes degree-of-freedom limiting components for restricting the movement of the insert along the x, y, and z axes. A flexible sensor is disposed on the lower surface of the insert, and a flexible circuit is disposed at the front end of the tool body. The pressure sensor and the flexible circuit are connected via flexible wires.

[0056] The flexible sensor is used to convert the deformation of the cutting tool under turning force into a voltage signal;

[0057] The flexible circuit is used to calculate the magnitude of the turning force based on the relationship between the voltage signal and the turning force.

[0058] This invention can measure the turning force of cutting tools of different shapes and sizes without damaging the original turning structure. A flexible sensor is set on the lower surface of the cutting tool to convert the deformation of the cutting tool under the action of turning force into an electrical signal. This improves the fit of the cutting tool during the turning process. The magnitude of the turning force is calculated based on the relationship between the electrical signal and the turning force, which can more accurately capture the changes in the cutting force of the cutting tool during the turning process. This achieves more accurate measurement of the turning force without interfering with or damaging the turning structure.

[0059] Example 1

[0060] See Figures 1-2 Example 1 provides a schematic diagram of the structure of an embedded flexible sensor turning force measuring tool, including a first tool body 1. The first tool body 1 includes a first cutting blade 6, a positioning component, and a clamping component for clamping the cutting blade. The positioning component includes a degree-of-freedom limiting component for restricting the movement of the cutting blade along the x-axis, y-axis, and z-axis directions.

[0061] The positioning component includes a first washer 9, a short cylindrical pin 7, and a first chamfered pin 5. The first cutter body 1 has two connected grooves 2. The first washer 9 and the first blade 6 are stacked sequentially on the upper surface of the first groove 201, and the first washer 9 is placed under the first blade 6. The first groove 201 is provided with a first through hole 2011 and a second through hole 2012. The short cylindrical pin 7 is provided in the first through hole 2011, and the first chamfered pin 5 is provided in the second through hole 2012. One end of the short cylindrical pin 7 and the first chamfered pin 5 are inserted into the first cutter body 1, and the other end is inserted into the first blade 6 through the first washer 9.

[0062] like Figure 2 The diagram shows a six-point positioning system for the cutting blade. The short cylindrical pin 7 restricts the first cutting blade 6's movement along the x-axis and y-axis (two degrees of freedom). The first chamfered pin 5 and the short cylindrical pin 7 restrict the first cutting blade 6's rotation around the z-axis (one degree of freedom). The first shim 9 restricts the first cutting blade 6's movement along the z-axis, rotation around the x-axis, and rotation around the y-axis (three degrees of freedom). This completes the positioning of the first cutting blade 6.

[0063] The clamping assembly includes a wedge 14, a round-headed screw 3, a spring washer 4, a bolt 12, and a stop 13. A spring washer 4 and a wedge 14 are provided on the upper surface of the second groove 202 in the y-direction of the first blade 6. The second groove 202 has a third through hole 2021, in which a round-headed screw 3 is provided. One end of the round-headed screw 3 passes through the blade body, and the other end passes through the wedge 14 via the spring washer 4. By adjusting the wedge 14 on the inclined blade body surface using the round-headed screw 3 and the spring washer 4 at the upper end of the wedge 14, clamping of the first blade 6 in the y-direction and z-direction is achieved.

[0064] A bolt 12 and a stop 13 are provided on the side of the first groove 201 in the x direction of the first blade 6. The bolt 12 and the stop 13 are threaded together. The first blade body 1 in the x direction is threaded together with the bolt 12 to push the stop 13 through the blind hole, thereby achieving clamping of the first blade 6 in the x direction.

[0065] A flexible circuit module 11 is attached to the lower front end of the first tool body 1, and a flexible sensor 8 is attached inside the first pad 9. The flexible sensor 8 is connected to the flexible circuit module 11 through a flexible wire 10, which facilitates the acquisition and signal processing of turning force.

[0066] like Figure 3 As shown, the flexible sensor includes a first encapsulation layer 801, a base layer 802, a sensitive layer 803, a conductive layer 804, and a second encapsulation layer 805; the first encapsulation layer 801, the base layer 802, the sensitive layer 803, the conductive layer 804, and the second encapsulation layer 805 are bonded together sequentially from bottom to top.

[0067] The first encapsulation layer 801 and the first gasket 9 are bonded together. The sensitive layer 803 and the conductive layer 804 are bonded together as the main body of the sensor to convert the turning force into an electrical signal. The second encapsulation layer 805 is located on the outermost layer of the sensor and is in direct contact with the cutting tool.

[0068] The encapsulation layer primarily protects sensor components, enhances mechanical flexibility, and provides waterproofing and dustproofing. The sensing layer, the core of the sensor, is made of a material with piezoresistive effect, converting mechanical signals into electrical signals and is mainly used for real-time monitoring of machining force information. The conductive layer connects the sensing layer to external circuitry, converting resistance changes into measurable electrical signals. The base layer primarily supports the sensor, stabilizes it, provides insulation protection, and supports the sensing element.

[0069] like Figure 4 As shown, the sensitive layer 803 includes a substrate 8031, eight electrodes 8032 and four symmetrically distributed resistor grids 8033. During operation, the four resistor grids 8033 are connected to an external voltage through the eight electrodes 8032 to form a Wheatstone bridge, and the output terminal of the Wheatstone bridge is connected to the signal input terminal of the terminal block through a connecting wire.

[0070] When the cutting tool is turning the workpiece, the cutting tool deforms under the action of the turning force, which in turn causes all four resistor grids 8033 to deform. At this time, the deformation of the two longitudinally distributed resistor grids 8033 is not equal to the deformation of the two transversely distributed resistor grids 8033, which causes the Wheatstone bridge to output a voltage signal. This voltage signal is sent online to the voltage feedback operational amplifier through the connecting wire and the terminal block in sequence.

[0071] In addition, the material of the sensitive layer can be selected from metals with good physical properties or conductive fillers incorporated into polymers to obtain sensitive materials with high physical properties.

[0072] The flexible sensor, as an inductive element for collecting turning force, changes the resistance of the inductive element when the sensitive layer is subjected to external vibration, thereby causing a change in current. The vibration signal is converted into an electrical signal, and then the turning force signal parameters are obtained and stored in the control device through signal amplification and A / D conversion.

[0073] The flexible sensor is mounted on the inner surface of the cutting tool, allowing the sensor to directly contact the surface of the cutting tool. This requires the sensor itself to be stretchable, compressible, and resistant to wear and damage.

[0074] like Figure 5As shown, the flexible circuit module 11 includes a circuit board 1101, a power module 1102, a wireless communication module 1103 and a control module 1104 disposed on the circuit board 1101, and the power module 1102 provides power to the wireless communication module 1103 and the control module 1104.

[0075] Specifically, the power module 1102 is a button battery, and the wireless communication module 1103 uses Bluetooth or other methods;

[0076] Wiring ports are reserved on the circuit board 1101. Then, the flexible circuit module 11 is covered on it and sealed around it to complete the encapsulation. Finally, the encapsulated module is glued to the blade body to form a whole.

[0077] Furthermore, the sensitive layer 803 of the flexible sensor 8 is electrically connected to the control module 1104. When the flexible sensor 8 deforms, the resistance value signal of the sensitive layer 803 changes. The resistance value signal is transmitted to the control module 1104 through the flexible wire 10. The processor core of the control module 1104 calculates the resistance value and transmits the data to the computer PC receiving device through the Bluetooth of the wireless communication module 1103.

[0078] like Figures 6-7 As shown, the turning force data acquisition structure includes the following four parts: a flexible sensor module, a signal acquisition module, a wireless communication module, and a data display and processing module.

[0079] The flexible sensor 8 is set on the lower surface of the cutting tool. The sensor's sensitive element receives external excitation (the detected cutting force), and the physical information non-electrical quantity is converted into electrical parameters (voltage or current) by the conversion element. Then, the electrical signal is micro-processed by the signal conditioning.

[0080] Then, the weak signal is amplified and pre-filtered by the signal acquisition module to achieve more accurate measurement.

[0081] After the input signal is properly conditioned, the ADC chip is used to convert the conditioned analog voltage signal into a digital signal of a specific magnitude and frequency that can be recognized by the STM32 microcontroller and stored in the register through the designed A / D conversion circuit.

[0082] The microprocessor uses an STM32 microcontroller as the main control chip to control the overall operation of the hardware device; the power module provides the operating voltage to each part of the hardware system circuit, and an external power supply circuit is designed to provide a stable power supply to each part of the hardware system through voltage transformation, filtering and current stabilization; the data display and processing module enables the computer and the microcontroller device to communicate and transmit data through Bluetooth wireless connection in the wireless communication module, and transmits the data to the PC to complete the display and analysis of the data results.

[0083] like Figure 8 As shown, the circuit schematic of the flexible piezoresistive sensor uses a Wheatstone bridge to build the bridge circuit. The change in resistance value can be converted into a change in voltage, thus establishing the relationship between the magnitude of the turning force and the output voltage. After passing through the filtering and signal amplification circuits, it is converted into a digital quantity and then the main control chip calculates the magnitude of the turning force.

[0084] By arranging and connecting the resistor grids into a bridge circuit using elastic elements, when the cutting tip is subjected to machining resistance, the cutting tool begins to deform. The elastic elements, acting as a strain transfer medium, cause the resistor grids to deform as well, resulting in a change in resistance value. This disrupts the original balance of the bridge circuit and outputs a voltage signal. By amplifying this signal and performing a series of processing steps, the magnitude of the force on the cutting tip, i.e., the turning force value, can be obtained.

[0085] The full-bridge circuit consists of four equal-arm resistors (R1 = R2 = R3 = R4 = R), where R1 and R2 are arranged parallel to the radial direction of the blade, and R3 and R4 are arranged perpendicular to the radial direction of the blade (i.e., parallel to the cross-section of the blade). Equation (1) is the derivation of the relationship between the output voltage and resistance change of the strain gauge bridge.

[0086]

[0087] Where U0 is the output voltage of the Wheatstone bridge, which is also the potential difference in the AC circuit, U1 is the external power supply voltage, I1 is the current in the series circuit of R1 and R3, I2 is the current in the series circuit of R2 and R4, and U... ab U is the voltage of line ab at R3. bc Let be the voltage of line bc at R2.

[0088] Initially, because the bridge circuit is in a balanced state, the output voltage U0 is zero.

[0089] U0=0 (2),

[0090] When the tool is cutting, the strain gauge deforms under stress. The magnitude of the stress can be calculated by measuring the output voltage value. In the Wheatstone full-bridge circuit, two of the four resistors are subjected to tensile force and two to compressive force.

[0091]

[0092] Considering small strain conditions Expanding after ignoring higher-order minor terms (1):

[0093]

[0094] When the strain configuration satisfies the symmetry condition:

[0095]

[0096] Substituting (5) into (4), we get:

[0097]

[0098] Where ΔR is the change in resistance, and ΔR1, ΔR2, ΔR3, and ΔR4 are the changes in the four resistances, respectively.

[0099] According to the strain effect formula, the relationship between the rate of change of resistance and strain is as follows:

[0100]

[0101] Substituting into the full-bridge formula (6), we obtain the output voltage:

[0102] U0=U1·GF·ε (8),

[0103] After transforming equation (8), the strain ε is obtained:

[0104]

[0105] According to Huke's Law, strain is converted into stress:

[0106]

[0107] Stress-to-cutting force mapping:

[0108]

[0109] By summarizing the final formula (11), the cutting force of the tool can be directly derived using the bridge voltage signal.

[0110] Where F is the cutting force, ε is the average strain, σ is the stress, GF is the strain gauge sensitivity coefficient, E is the elastic modulus of the tool material, and A is the cross-sectional area of ​​the strain gauge sensitive region.

[0111] like Figure 9As shown in the circuit diagram of the flexible sensor electronic interface, the control device includes a voltage divider (the circuit connected to the MCU) and a microcontroller (MCU), which is connected to the Bluetooth module in the communication module. The control center is connected to other circuit modules via a bus, which reserves an external interface as the access point for the cutting force acquisition module. The voltage divider used for sensor signal conditioning and the microcontroller (MCU) with multiple A / D converter channels form the turning force preprocessing circuit, which aims to convert the turning force information into a digital signal that the controller can recognize. This electronic interface has a simple structure, a large dynamic measurement range, and is easy to operate, using a voltage divider for signal conditioning. The voltage signal from the voltage divider is sent to the embedded A / D converter channel (ADC). The analog reference voltage of the ADC can be selected according to the positive and negative power supply voltage of the microcontroller, and it is also the power supply for the voltage divider. When the power supply voltage changes, the sensor's voltage divider and the ADC's reference voltage change simultaneously. Since the ADC's configured sampling value remains stable, the influence of power supply interference is effectively avoided. At the end of the scan round, all Rsen data is sent to the communication module via the serial port and wirelessly transmitted to the remote receiver PC via the RF antenna. The remote receiver is equipped with a Bluetooth module that enables it to receive data from a variety of devices via a virtual serial port without a physical connection.

[0112] like Figure 10 As shown in the schematic diagram, the power supply module is powered by an external 5V battery. The 5V to 3.3V circuit is composed of a forward voltage regulator chip. The LM1117-3.3 linear regulator has current limiting and overheat protection functions, which meet the usage requirements while having high conversion efficiency. Figure 10 C5 and C6 are input power filter capacitors, while C7, C8, and C9 are output power filter capacitors. Their energy storage characteristics prevent sudden voltage changes and self-oscillation, providing stable operating voltages for all system modules. At the 3.3V output, inductor L1 and capacitors together form an LC filter to filter out high-frequency noise from the input power supply, ensuring stable input voltage to the transformer. The power module is the power supply component of the entire acquisition system, and its quality is closely related to the overall system stability. The flexible sensor and amplifier input voltage are 5V, while the power ports of the communication chip microcontroller, general-purpose input / output ports, and the Bluetooth power supply module are all 3.3V. Therefore, a low-dropout regulator is needed to convert the 5V to 3.3V.

[0113] like Figure 11 As shown, the main component of the signal conditioning circuit diagram is a Wheatstone bridge, a circuit used to accurately measure changes in resistance, which is used to convert changes in the mechanical quantity of the turning force into a measurable electrical signal.

[0114] When the cutting force changes, the sensor's resistance changes accordingly. This change is converted into a voltage signal by a bridge circuit, facilitating subsequent signal processing and analysis. Initially, the bridge is balanced, meaning the voltage difference across it is zero. When the sensor is subjected to cutting force, the bridge's balance is disrupted, generating a voltage difference. This voltage difference is proportional to the resistance change and can be used to determine cutting parameters. For anti-aliasing filtering, the sampling frequency should be greater than twice the highest frequency in the signal; otherwise, high-frequency signals in the analog signal will be superimposed on low-frequency components, causing aliasing. Therefore, a low-pass filter is used during data acquisition to remove high-frequency components and resolve frequency aliasing. The filtering circuit uses passive filtering, employing passive L and C components to reduce the impedance of the corresponding harmonic current paths, effectively reducing system power consumption compared to active filtering. The differential signal output by the sensor passes through an anti-aliasing filter to remove aliasing frequency components. The amplification circuit consists of a high-precision instrumentation amplifier INA126 and a precision reference voltage source, amplifying the sensor signal to a standard 0-5V signal. By adjusting the resistance value of resistor RG, the amplifier circuit can achieve a gain from 1x to 1000x. When the gain G = 1000, the amplifier circuit still has a bandwidth of 10kHz, which fully meets the data sampling frequency requirements during high-speed turning. The Ref pin of amplifier INA126 is connected to a precision reference voltage source. Since this module is a mixed-signal circuit, to reduce the influence of the digital part on the analog part, the digital part needs to be separated from the analog part, and the digital ground and analog ground need to be separated and connected through a 0Ω resistor. The output wire of amplifier INA126 is connected to the ADC analog-to-digital conversion module in the microcontroller, and the latter part is used for information acquisition, storage and processing.

[0115] like Figure 12 As shown, in the Bluetooth data transmission process, the Bluetooth module is connected to the interface of the MCU acquisition board. The module is configured according to the prompts printed by the network debugging assistant. After configuration, the control module transmits data with the computer. Although Bluetooth can send and receive data, this embodiment only uses the Bluetooth data reception function. Therefore, only the data reception function is analyzed. The main procedures include Bluetooth initialization, setting the address for receiving data, data storage, and data transmission.

[0116] like Figure 13As shown, the lower-level machine process mainly involves the lower-level machine (microcontroller) receiving sensor signals, processing the signals, and controlling the turning process according to a preset program. The operation flow of the lower-level machine in the flexible sensor measurement turning system is described. The main software programs include microcontroller main control chip initialization, AD conversion program, serial communication program, etc. Start: The system powers on and begins executing the program. System Initialization: The lower-level machine performs self-checks, initializes I / O ports, configures interrupts, etc. Signal Acquisition: The sensor detects the physical quantity of the turning force during the turning process and sends the signal to the lower-level machine. Signal Conditioning: The sensor signal is amplified, filtered, isolated, etc., to meet the input requirements of the lower-level machine. A / D Conversion: The conditioned signal is converted into a digital signal that the lower-level machine can process. Data Reading: When reading data, attention should be paid to the data type and register size to avoid data overflow or truncation. Digital Signal Processing: The process by which the microcontroller processes and analyzes digital signals, which are analog signals converted into digital signals by an analog-to-digital converter (ADC). Performs necessary mathematical operations, such as Fourier transforms, correlation operations, and convolutions. Serial communication: The process by which the microcontroller exchanges data with other devices through a serial interface. Compared to parallel communication, data is transmitted sequentially, bit by bit. After data reception, corresponding processing can be performed. PC terminal: Digital signals are wirelessly transmitted to the PC via Bluetooth for display, analysis, and processing of cutting data. End: When the turning process is complete, the system can be shut down or reset for future use.

[0117] like Figure 14 As shown, the system software feedback control flow initializes after the entire system is powered on. Raw voltage data is acquired through the ADC port of the acquisition circuit. This raw data needs to be filtered by the microcontroller chip's internal program to obtain smooth data. After filtering, further processing is required. Based on the basic principle of voltage divider circuits, the voltage divider formula is converted into code, allowing the calculation of the actual resistance value of the flexible piezoresistive sensor. During the turning force test, the acquired resistance value can be displayed in real-time on the computer via a wireless Bluetooth device, facilitating debugging and optimization. The calculated data requires final processing, adjusting based on the resistance change characteristics of the flexible piezoresistive sensor.

[0118] The program determines whether the sensor has reached the required deformation by setting an appropriate threshold. When the resistance of the flexible piezoresistive sensor reaches the set threshold, the program makes a judgment and proceeds to the next step, setting the flag of the sensor that detected the change to 1, and simultaneously sending the sensor number and the flag bit to the data receiver. After receiving the data, the data receiver needs to parse and process the data according to the pre-set encoding rules to know that the flexible sensor has detected the change in data.

[0119] The data is used for control calculations, and control signals are generated based on error values ​​(such as PID algorithms). The actuators are then further controlled, converting the control signals into physical actions (adjusting tool feed rate / rotational speed parameters). A closed-loop judgment is formed, continuously monitoring the stability of the cutting force and dynamically adjusting until the system stabilizes.

[0120] like Figure 15 As shown in the diagram, the cutting monitoring closed-loop feedback control system mainly includes a sensor module, a control module, an execution module, and an interaction module. These four modules, together with the real-time cutting force, form a closed-loop feedback control. The signal flow path is: cutting force—sensor—signal conditioning—ADC—digital processing—PID calculation—DAC—actuator—adjustment parameters—affecting the cutting process—feedback to the sensor, forming a closed loop.

[0121] The sensor module directly contacts the cutting tool to collect the raw force signal and performs signal conditioning. The real-time cutting force signal is then transmitted to the control module for further data processing and to generate control signals.

[0122] The control module converts analog signals into digital signals (ADCs), performs digital filtering and feature extraction using a data processor, and then uses an intelligent controller (PID algorithm) to generate control commands, which are transmitted to the execution module via a DAC (digital-to-analog converter). In the execution module, the servo drive and frequency converter first convert the analog and PWM signals from the control commands into corresponding torque and speed commands, which are then used to adjust the cutting state of the tool by correspondingly influencing the spindle motor and feed motor. The actual spindle motor speed and the actual feed rate of the feed motor are fed back to the controller, which simultaneously monitors both speed and feed rate, forming a dual closed-loop control system.

[0123] The interactive module allows users to set cutting parameter thresholds via a human-machine interface. The controller compares real-time cutting force data with the set parameters and outputs control commands accordingly. Data storage records historical data, which is then fed into the data processor for subsequent process optimization.

[0124] The modules in the above-mentioned cutting monitoring closed-loop feedback control system form a closed-loop feedback, which not only dynamically adjusts the spindle speed and feed rate synchronously based on the deviation between the real-time cutting force and the set value, but also triggers an emergency stop mechanism for safety protection when abnormal force fluctuations are detected.

[0125] Example 2

[0126] like Figure 16As shown, this embodiment provides a flexible measuring device for a lever-type cutting tool, mainly retaining the turning force acquisition module, information processing and transmission module, communication module, and power management module based on Embodiment 1. The specific functions of the turning force acquisition module, communication module, and power management module are similar to those in Embodiment 1, and will not be elaborated further here. The difference from Embodiment 1 is that this flexible sensor measuring system is implemented in a different cutting tool structure.

[0127] See Figure 16 and Figure 17 A schematic diagram of a flexible measurement system device in a lever-type cutting tool. The cutting tool structure includes a second cutting tool body 15, which includes a second cutting blade 16, a positioning assembly, and a clamping assembly for clamping the cutting blade. The positioning assembly includes a degree-of-freedom limiting assembly for restricting the movement of the second cutting blade 16 along the x-axis, y-axis, and z-axis directions.

[0128] The positioning assembly includes a tapered lever pin 17, a second chamfered pin 18, and a second washer 19. A V-shaped groove is formed on the second cutter body 15. The upper surface of the V-shaped groove is sequentially stacked with the second washer 19 and the second blade 16, with the second washer 19 positioned below the second blade 16. The V-shaped groove has a third through hole 20 and a fourth through hole 21. The tapered lever pin 17 is housed in the third through hole 20, and the second chamfered pin 18 is housed in the fourth through hole. One end of the tapered lever pin 17 and the second chamfered pin 18 penetrates the second cutter body 15, and the other end passes through the second washer 19 and into the second blade 16. The tapered lever pin 17 restricts the movement of the second blade 16 in the x-axis and y-axis directions (two degrees of freedom). The tapered lever pin 17 and the second chamfered pin 18 restrict the rotation of the second blade 16 in the z-axis direction (one degree of freedom). The second washer 19 restricts the rotation of the second blade 16 about the x-axis, the rotation about the y-axis, and the movement along the z-axis (three degrees of freedom). This completes the positioning of the second blade 16. Figure 18 The diagram shown is a schematic of the six-point positioning of the blade in a lever-pin structure.

[0129] Specifically, the second blade 16 is a rhomboid blade;

[0130] Specifically, the third through hole 20 is a stepped surface that is narrow at the bottom and wide at the top. Spring coils 22 are symmetrically arranged on both sides of the upper stepped surface. The upper end face of the tapered spur pin 17 is placed at the stepped hole position of the tool body and the spring coil 22 is inserted into the upper end face, which improves the stability of the tapered spur pin 17 connector and reduces and absorbs impact loads during turning.

[0131] The clamping assembly includes a pressure plate 23, a slotted conical end clamping screw 24, and a conical lever pin 17. The conical lever pin 17 is arranged in the y-direction of the second blade 16. A fifth through hole 25 is provided in the blade body, and the slotted conical end clamping screw 24 is provided in the fifth through hole 25. The top end of the slotted conical end clamping screw 24 abuts against the tail end of the conical lever pin 17. Using the lever principle, the conical lever pin 17 clamps the second blade 16, causing the second blade 16 to be stuck in the V-groove of the second blade body 15, thereby achieving clamping of the second blade 16 in the x-axis and y-axis directions.

[0132] A pressure plate 26 is provided in the z-direction of the second blade 16. The pressure plate 26 can be longitudinally adjusted according to the thickness of the second blade 16 by means of hexagonal screws 27, so as to achieve clamping of the second blade 16 in the z-axis direction.

[0133] The second blade 16 is placed on the upper end of the second cutter body 15 and the plane of the second blade 16 is cut. The trapezoidal holes of the spring coil 22 and the tapered bar pin 17, as well as the through hole of the second chamfered pin 18, are all machined by boring from top to bottom. The internal thread at the lower right end of the cutter head of the second cutter body 15 and the protruding part of the cutter head perpendicular to the right end face are machined by milling threads.

[0134] Example 3

[0135] See Figure 18 This embodiment provides a flexible turning force measuring machine tool device, including a bed 28. One end of the bed 28 is equipped with a bracket 29 and a headstock 34, and the other end is fixed with a tailstock 30. A feed module is provided in the middle. A support base is fixed on the bracket 29, and a spindle 31 and a drive motor 32 are fixed on the support base. One end of the spindle 31 is connected to a first gear 44, and the other end is connected to a chuck 33 that holds the workpiece. One end of the drive motor 32 is connected to a second gear 45, and the other end is fixed to the support base. The teeth of the first gear 44 and the second gear 45 mesh with a toothed belt 46. The drive motor 32 drives the toothed belt 46 to rotate the spindle 31 connected to the first gear 45, thereby rotating the chuck 33 fixed on the spindle 31 and holding the workpiece.

[0136] The feed module includes a lateral movement component, a longitudinal movement component, and a sliding block 37;

[0137] The lateral movement assembly includes a lead screw 35, a feed axis 36, and a first sliding handle 43. One end of the lead screw 35 is connected to the headstock 34, and the other end passes through the tailstock 30 and is connected to the first sliding handle 43. One end of the feed axis 36 is connected to the headstock 34, and the other end passes through the sliding block 37 and is fixed to the tailstock 30. By rotating the first sliding handle 43, the lead screw 35 is driven to move the sliding block 37 laterally, thereby driving the tool clamping part to move the tool laterally.

[0138] The longitudinal movement assembly includes a fixed plate 47, a first slide box 38, a second slide box 39, a threaded rod 40, a tool holder 41, and a second sliding handle 42. The fixed plate 47 is provided on the sliding block 37, and the first slide box 38 and the second slide box 39 are fixed on the fixed plate 47. The threaded rod 40 is fixed between the first slide box 38 and the second slide box 39. One end of the threaded rod 40 is fixed to the first slide box 38, and the other end passes through the second slide box 39 and connects to the second sliding handle 42. The tool holder 41 is mounted on the threaded rod 40, and the tool as in Embodiment 1 or Embodiment 2 is mounted on the tool holder 41. By rotating the second sliding handle 42, the threaded rod 40 is driven to move the tool clamped on the tool holder 41 longitudinally.

[0139] like Figure 19 The turning process shown is as follows: Start: The system powers on and begins executing the program. System Initialization: The lower-level machine performs a self-check, initializes I / O ports, and configures interrupts and timers, etc. Waiting for Sensor Signals: The lower-level machine enters a waiting state, ready to receive signals from the flexible sensor. Receiving Sensor Signals: The flexible sensor detects the turning force signal during the turning process and sends the signal to the lower-level machine. Signal Conditioning: The flexible sensor signal is amplified, filtered, isolated, and conditioned to meet the input requirements of the lower-level machine. Converting to Standard Signal: The conditioned signal is converted into a digital signal that the lower-level machine can process (e.g., ADC conversion). Determining if the Signal is Within Normal Range: The lower-level machine determines whether the signal indicates a normal turning state based on a preset threshold. Executing Normal Cutting Control Program: If the signal is normal, the lower-level machine continues to execute the preset turning control program. Monitoring the Turning Process: The lower-level machine continuously monitors the flexible sensor signal to control the turning process in real time. If Turning is Completed: When the lower-level machine detects that the turning task is complete, it stops turning. Recording Data: Relevant data during the turning process is recorded for subsequent analysis and optimization. Determine if it's a minor anomaly: If the signal is abnormal but not a serious problem, try adjusting the turning parameters to restore normal operation. Determine if it's a serious anomaly: If the signal indicates a serious problem, trigger an alarm and stop turning. Execute the error handling procedure: The lower-level computer executes the error handling procedure, attempting to resolve the problem and resume turning.

[0140] End: The turning process is complete. The system can be shut down or reset for the next use.

[0141] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A cutting tool for measuring turning force using an embedded flexible sensor, characterized in that, The blade body includes a blade, a positioning assembly, and a clamping assembly for clamping the blade; the positioning assembly includes components for limiting the blade along... x axis, y Degrees of freedom constraint components for motion in the z-axis and z-axis directions; A flexible sensor is provided on the lower surface of the blade, and a flexible circuit module is provided at the front end of the blade body. The flexible sensor and the flexible circuit module are connected by a flexible wire. The flexible sensor is used to convert the deformation of the cutting tool under turning force into a voltage signal; The flexible circuit module is used to calculate the magnitude of the turning force based on the mapping relationship between the voltage signal and the turning force. The positioning component includes a washer, a short cylindrical pin, and a chamfered pin. The cutter body has two connected grooves. The upper surface of the first groove is stacked with a washer and a blade, and the washer is placed under the blade. The first groove has a first through hole and a second through hole. The first through hole contains a short cylindrical pin, and the second through hole contains a chamfered pin. One end of the short cylindrical pin and the chamfered pin passes through the cutter body, and the other end passes through the washer and into the blade. The clamping assembly includes a wedge, a round-headed screw, a spring washer, a bolt, and a stop; for the blade. y The upper surface of the second groove in the direction is provided with a spring washer and a wedge. The second groove has a third through hole, and a round-headed screw is installed in the third through hole. One end of the round-headed screw passes through the blade body, and the other end passes through the spring washer and into the wedge. x A bolt and a stop are provided on the side of the first groove in the direction, and the bolt and the stop are threaded together. x The threaded connection screw of the tool body in the direction of the direction pushes the stop block into the blind hole; The mapping relationship between voltage signal and turning force is as follows: ， ， ， in, For cutting force, For stress, The strain gauge sensitivity coefficient, The elastic modulus of the tool material. The cross-sectional area of ​​the strain gauge's sensitive region is... This is the output voltage of the Wheatstone bridge. The voltage of the AC line. For line ab in Voltage at that point For line bc in Voltage at that point This is the external power supply voltage. for and The current in a series circuit, for and The current in a series circuit, , , and These are the four equal-arm resistors of the full-bridge circuit.

2. The embedded flexible sensor turning force measuring tool as described in claim 1, characterized in that, The flexible sensor includes a first encapsulation layer, a base layer, a sensitive layer, a conductive layer, and a second encapsulation layer; the first encapsulation layer, the base layer, the sensitive layer, the conductive layer, and the second encapsulation layer are bonded together sequentially from bottom to top; the first encapsulation layer is bonded to a gasket, and the sensitive layer and the conductive layer are bonded together to form the main body of the sensor for converting turning force into an electrical signal; the second encapsulation layer is located on the outermost layer of the sensor and is in direct contact with the cutting blade.

3. The embedded flexible sensor turning force measuring tool as described in claim 2, characterized in that, The sensitive layer includes a substrate, symmetrically distributed resistive grids and electrodes disposed on the substrate; the symmetrically distributed resistive grids include a first resistor parallel to the radial direction of the blade. Second resistor The third resistor perpendicular to the radial direction of the blade and the fourth resistor The first resistor Second resistor Third resistor and the fourth resistor A Wheatstone bridge is formed by connecting electrodes to an external voltage, and the output of the Wheatstone bridge is connected to the input of the flexible circuit module.

4. The embedded flexible sensor turning force measuring tool as described in claim 1, characterized in that, The flexible circuit module includes a flexible circuit board, a wireless communication module and a control module mounted on the flexible circuit board. The control module includes a signal amplification circuit, an A / D conversion circuit and a microprocessor. One end of the signal amplification circuit is connected to the flexible sensor and the other end is connected to the input terminal of the A / D conversion circuit. The output terminal of the A / D conversion circuit is connected to the microprocessor module. The microprocessor module is used to calculate the magnitude of the turning force based on the relationship between the electrical signal and the turning force.

5. The embedded flexible sensor turning force measuring tool as described in claim 1, characterized in that, The positioning component is replaced with a tapered lever pin, a chamfered pin, and a washer. A V-shaped groove is formed on the cutter body. The washer and the blade are stacked sequentially on the upper surface of the V-shaped groove, and the washer is placed under the blade. The V-shaped groove is provided with a first through hole and a second through hole. The tapered lever pin is provided in the first through hole, and the chamfered pin is provided in the second through hole. One end of the tapered lever pin and the chamfered pin passes through the cutter body, and the other end passes through the blade through the washer.

6. The embedded flexible sensor turning force measuring tool as described in claim 1, characterized in that, The clamping assembly is replaced with a clamping plate, a slotted conical clamping screw, and a conical lever pin, for the blade. y A tapered lever pin is provided in the direction of the blade body, and a third through hole is provided in the blade body. A slotted conical end clamping screw is provided in the third through hole. The top of the slotted conical end clamping screw reaches the tail end of the tapered lever pin, so that the diamond-shaped blade is stuck in the V-groove of the blade body; a pressure plate is provided in the z-direction of the blade.

7. A machine tool for measuring turning force using an embedded flexible sensor, characterized in that, The machine tool includes a machine tool bed, one end of which is equipped with a support and a headstock, and the other end is fixed with a tailstock. The support is provided with a chuck for clamping the workpiece. A feed module is provided between the headstock and the tailstock, and the feed module is equipped with an embedded flexible sensor turning force measuring tool as described in any one of claims 1-6.

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