A cutting force self-sensing turning tool system and method

Abstract

The application discloses a cutting force self-sensing turning tool system and method, which comprises a tool shank tail, a groove, a tool head, a blade and a blade groove; the tool shank tail is connected with the tool head through a tool shank, the tool shank is an elastic square beam, the tool head is partially provided with the blade groove, the blade is arranged in the blade groove, four surfaces of the tool shank close to the tool head are provided with four grooves which are completely identical in structure, the grooves are sensing parts of the cutting force self-sensing turning tool system, and a self-sensing component is fixedly integrated on the four surfaces of the grooves. The application has simple structure, only needs to arrange the grooves on the tool shank close to the tool head, integrates the self-sensing component on the surfaces of the grooves, has low manufacturing cost and high measurement precision.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of turning force measurement in turning processing, and particularly relates to a cutting force self-sensing turning tool system and method. BACKGROUND

[0002] On-line monitoring of tool cutting state can not only improve processing efficiency and tool utilization rate, but also prevent serious consequences such as damage to fixtures and workpieces caused by tool wear and breakage. Cutting force is one of the basic signals that can best reflect the information of the cutting process, and is the most widely used signal for cutting process monitoring. It is closely related to tool parameters, cutting conditions, tool state and workpiece surface quality. Therefore, cutting force on-line state measurement is one of the most direct, effective and common ways in cutting on-line state monitoring.

[0003] Under the existing technical conditions, the measurement of turning force is mainly realized by strain gauge dynamometers or piezoelectric dynamometers installed on the tool. However, due to the limitations of their own structure and installation method, the following problems exist: for the strain gauge dynamometer, due to the limitations of the resistance strain gage pasting process, on the one hand, it leads to low measurement accuracy, and on the other hand, it is not suitable for use in high temperature environment, thereby limiting its scope of application. For the piezoelectric dynamometer, due to the insufficient unidirectionality of the piezoelectric crystal, it leads to mutual interference when measuring three-way force and hysteresis when measuring static force, thereby leading to low measurement accuracy. Both strain gauge dynamometers and piezoelectric dynamometers are limited in their scope of application due to their large size.

[0004] For the existing self-sensing tool, not only is the structure complex, but also the measurement accuracy is improved only from the tool structure and the accuracy of the self-sensing component. There is little research on the optimization of decoupling algorithm. However, the decoupling algorithm has a great influence on the accuracy of the self-sensing system. In the existing decoupling algorithm, the tool stress position is defaulted as a point on the center axis or the entire cross section of the tool bar, and the influence of the tool tip position, other geometric parameters of the tool and the tool cutting parameters on the voltage output of the self-sensing component is not considered. Therefore, the existing decoupling algorithm has a great adverse effect on the self-sensing accuracy of the cutting force. SUMMARY

[0005] In order to overcome the above technical problems, the purpose of the present application is to provide a cutting force self-sensing turning tool system and method, which has a simple structure, only needs to set a groove on the tool bar near the tool head, and has low manufacturing cost and high measurement accuracy.

[0006] In order to achieve the above purpose, the technical scheme adopted by the present application is:

[0007] A cutting force self-sensing turning tool system, comprising a tool holder tail 1, a groove 2, a tool head 7, a tool insert 8 and a tool insert groove 9;

[0008] The tool holder tail 1 is connected with the tool head 7 through a tool holder, the tool holder is a flexible square beam, the tool head 7 is partially provided with the tool insert groove 9, the tool insert 8 is arranged in the tool insert groove 9, four surfaces of the tool holder close to the tool head 7 are provided with four grooves 2 which are completely identical in structure, the grooves 2 are sensing parts of the cutting force self-sensing turning tool system, and self-sensing components are fixedly integrated on the four surfaces of the grooves 2.

[0009] A fastening screw 10 is arranged to fix the tool insert 8 in the tool insert groove 9; the self-sensing components comprise a No. 1 self-sensing component 3, a No. 2 self-sensing component 4, a No. 3 self-sensing component 5 and a No. 4 self-sensing component 6.

[0010] The four sets of self-sensing components are completely identical, independently work and do not affect each other.

[0011] The voltage signals output by the self-sensing components are first amplified by a signal amplifier, then collected by a data acquisition card and transmitted to a computer system, the computer uses a labview software to build a data conversion platform according to a decoupling algorithm, and converts the voltage signals into three-directional cutting force signals.

[0012] The decoupling algorithm accurately converts four voltage signals output by the sensing system of the turning tool in various cutting states into real-time cutting force signals.

[0013] The turning tool insert 8 adopts a indexable insert.

[0014] The four sets of self-sensing components are completely identical, independently work and do not affect each other. The self-sensing components comprise a flexible substrate and four resistance strain gauges (or two resistance strain gauges and two fixed resistors), in each set of self-sensing component structure, a half-bridge direct current circuit is selected as a measurement circuit of the strain gauge, the bridge comprises four pure resistance bridge arms, wherein the pulling and pressing working direction of the resistance strain gauge is consistent with the cutting resistance direction of the tool holder, U0 is a power voltage, and is an output voltage; wherein R1 and R4 are resistance strain gauges, which change with the change of the strain of the tool holder (the tool holder is positively strained by pulling, the strain gauge is pulled to cause the resistance value of the strain gauge to increase; conversely, the tool holder is negatively strained by pressing, the strain gauge is pressed to cause the resistance value of the resistance strain gauge to decrease), R2 and R3 are fixed values; when the self-sensing component is strained to cause the resistance values to change ΔR1, ΔR4 R1→R1+ΔR1, R4→R4+ΔR4, the balance state of the bridge is destroyed, a voltage is generated, and the form of the bridge output voltage is:

[0015]

[0016] Four resistance strain gauges (or two resistance strain gauges and two fixed resistances) are integrated on the same side of a rectangular elastic substrate to form a half-bridge differential bridge circuit, which not only eliminates non-linear errors, but also compensates for temperature errors.

[0017] A method of using a cutting force self-sensing turning tool system, comprising the following steps:

[0018] If the self-sensing accuracy requirement of the cutting force self-sensing turning tool system is low, and the error caused by the position of the tool tip on the self-sensing result is not considered, the following steps are included:

[0019]

[0020] In the formula, F f , F p , F c are the feed force, the cutting resistance and the main cutting force, respectively, U1, U2, U3, U4 are the output voltages of the four sets of self-sensing components, respectively, K X , K Y , K Z are the sensitivities of the groove self-sensing components in the feed force, cutting resistance and main cutting force directions, respectively, and are obtained by the following formula:

[0021]

[0022]

[0023]

[0024] In the formula, U0 is the input voltage of the self-sensing component, K0 is the sensitivity coefficient of a single resistance wire in the self-sensing component, l is the total length of the resistance wire, L is the total length of the tool bar, y1 and y2 are the distances from the proximal and distal ends of the groove to the clamping position at the tail of the tool bar, respectively, E is the elastic modulus of the tool bar, A and A' are the cross-sectional areas of the tail of the tool bar and the groove part, respectively, a, b, a' and b' are the lengths of the cross-sections of the tail of the tool bar and the groove part in the feed force direction and the main cutting force direction, respectively, and K0 can be obtained by the following formula:

[0025] K0 = (1 + 2μ + λE)

[0026] In the formula, E is the elastic modulus of the resistance wire material, λ is the piezoresistive coefficient, which is related to the material properties, and μ is the Poisson's ratio of the resistance wire material.

[0027] If the self-sensing accuracy requirement of the cutting force self-sensing turning tool system is high, the error caused by the position of the tool tip on the self-sensing result needs to be considered, and the following steps are included:

[0028]

[0029] wherein c and d are the distances from the tool tip to the center axis of the tool holder in the feed force and the main cutting force directions, K X , K Y , K Z are the sensitivity coefficients of the sensitive parts of the tool holder in the X (feed force direction), Y (thrust force direction), and Z (main cutting force direction), U1, U2, U3, and U4 are the output voltages of the four sets of self-sensing components, F f , F p , F c are the feed force, the thrust force, and the main cutting force, respectively.

[0030] If the self-sensing accuracy of the self-sensing cutting tool system is very high, not only the error caused by the tool tip position to the self-sensing result needs to be considered, but also the error caused by the tool geometry parameters and the cutting parameters to the self-sensing result needs to be considered, including the following steps:

[0031]

[0032] wherein c and d are the distances from the tool tip to the center axis of the tool holder in the feed force and the main cutting force directions, K X , K Y , K Z are the sensitivity coefficients of the sensitive parts of the tool holder in the X (feed force direction), Y (thrust force direction), and Z (main cutting force direction), U1, U2, U3, and U4 are the output voltages of the four sets of self-sensing components, F f , F p , F c are the feed force, the thrust force, and the main cutting force, respectively, and a p and γ0 are the back engagement amount and the tool rake angle, respectively.

[0033] The beneficial effects of the present application are:

[0034] The system of the present application has a simple structure, and only needs to set a groove on the tool holder close to the tool head part, and the self-sensing components can be integrated on the surface of the groove;

[0035] For different accuracy requirements, when the self-sensing accuracy requirement is low, the decoupling algorithm which does not consider the tool tip position and other tool geometry parameters and cutting parameters can be used, and this algorithm is simple and convenient to calculate;

[0036] When the self-sensing accuracy requirement is high, the method considering the tool tip position is used, and the calculation difficulty of this method is larger than that of the former, but the accuracy can be obviously improved;

[0037] When the self-sensing accuracy requirement is very high, the method considering the tool tip position and other geometric parameters and cutting parameters of the tool is adopted, the calculation difficulty of the method is greater than that of the above two methods, but the accuracy is very high. BRIEF DESCRIPTION OF DRAWINGS

[0038] Figure 1 It is a structure schematic diagram of the cutting force self-sensing turning tool system of the application.

[0039] Figure 2 It is a three-view of the first self-sensing component.

[0040] Figure 3 It is a three-view of the second self-sensing component.

[0041] Figure 4 It is a three-view of the third self-sensing component.

[0042] Figure 5 It is a three-view of the fourth self-sensing component.

[0043] Figure 6 It is a bridge circuit diagram of the first self-sensing component.

[0044] Figure 7 It is a bridge circuit diagram of the second self-sensing component.

[0045] Figure 8 It is a bridge circuit diagram of the third self-sensing component.

[0046] Figure 9 It is a bridge circuit diagram of the fourth self-sensing component.

[0047] Figure 10 It is a circuit connection mode diagram of the self-sensing component

[0048] Figure 11 It is a process schematic diagram of equivalent conversion of the stress position from the tool tip to the tool bar axis.

[0049] Figure 12 It is a tool cutting geometric position schematic diagram.

[0050] Figure 13 It is a cutting force self-sensing tool front view and top view.

[0051] In the diagram: 1-Tail end of the tool holder; 2-Groove; 3-Self-sensing component No. 1; 4-Self-sensing component No. 2; 5-Self-sensing component No. 3; 6-Self-sensing component No. 4; 7-Tool head; 8-Blade; 9-Blade groove; 10-Fastening screw; 301-Elastic substrate of self-sensing component No. 1; 302-Strain gauge No. 1 of self-sensing component No. 1; 303-Strain gauge No. 2 (or fixed resistor) of self-sensing component No. 1; 304-Strain gauge No. 3 (or fixed resistor) of self-sensing component No. 1; 305-Strain gauge No. 4 of self-sensing component No. 1; 401-Elastic substrate of self-sensing component No. 2; 402-Strain gauge No. 1 of self-sensing component No. 2; 403-Strain gauge No. 2 (or fixed resistor) of self-sensing component No. 2; 404 - Strain gauge #3 (or fixed resistor) of self-sensing component #2; 405 - Strain gauge #4 of self-sensing component #2; 501 - Elastic substrate of self-sensing component #3; 502 - Strain gauge #1 of self-sensing component #3; 503 - Strain gauge #2 (or fixed resistor) of self-sensing component #3; 504 - Strain gauge #3 (or fixed resistor) of self-sensing component #3; 505 - Strain gauge #4 of self-sensing component #3; 601 - Elastic substrate of self-sensing component #4; 602 - Strain gauge #1 of self-sensing component #4; 603 - Strain gauge #2 (or fixed resistor) of self-sensing component #4; 604 - Strain gauge #3 (or fixed resistor) of self-sensing component #4; 605 - Strain gauge #4 of self-sensing component #4. Detailed Implementation

[0052] The present invention will now be described in further detail with reference to the accompanying drawings.

[0053] Example 1

[0054] like Figures 1-13 As shown: A cutting force self-sensing turning tool system and its decoupling algorithm, the cutting force self-sensing turning tool system includes a tool holder tail 1, a groove 2, a self-sensing component, a tool head 7 and an insert 8.

[0055] The tool holder is a flexible square beam, and the tool head 7 has a cutting insert groove 9. A fastening screw 10 fixes the cutting insert 8 in the cutting insert groove 9. Four identical grooves 2 are set on the four surfaces of the tool holder near the tool head 7. These grooves 2 are the sensing parts of the self-sensing cutting force turning tool system, and four sets of self-sensing components are fixedly integrated on the four surfaces of the grooves 2. A decoupling algorithm accurately converts the four voltage signals output by the sensing system under various cutting conditions into real-time cutting force signals.

[0056] The elastic material of the entire tool holder is 40Cr and 42CrMo.

[0057] Reference Figure 1, the tool head 7 is provided with a blade slot 9 for mounting a blade 8, the blade 8 is mounted in the blade slot 9 through a fastening screw 10, and the mounted blade 8 is an indexable blade. The tool bar is provided with a groove 2 near the tool head 7 part, and four self-sensing components are mounted on the four faces of the groove 2. The four sets of self-sensing components have the same structural performance parameters, and each includes an elastic substrate and four resistance strain gages. Figure 3 Figure 4 The resistance specific position and connection diagram is shown.The bridge includes four pure resistance bridge arms, U0 is the power supply voltage, and U is the output voltage. Among them, R1 and R4 are resistance strain gages, which change with the change of the strain of the tool bar, and R2 and R3 are fixed values. When the self-sensing component is strained and causes the resistance value to change ΔR1, ΔR4 (R1→R1+ΔR1, R4→R4+ΔR4), the balance state of the bridge is destroyed, and a voltage output is generated.

[0058] If the precision requirement is not high during the cutting process of the tool, the influence of the tool tip position on the output result of the sensing component does not need to be considered, or the tool tip is located at a point on the center axis of the tool bar, and the decoupling algorithm considering the influence of the tool tip position on the self-sensing result is used for decoupling of the sensing signal.

[0059] If the precision requirement is high during the cutting process of the tool, and the tool tip position is not collinear with the center axis of the tool bar, the influence of the tool tip position on the output result of the sensing component needs to be considered. In this case, the stress result of the tool tip needs to be equivalent to the center axis of the tool bar, and the decoupling algorithm considering the influence of the tool tip position on the self-sensing result is used for decoupling of the sensing signal.

[0060] If the precision requirement is extremely high during the cutting process of the tool, and the tool tip position is not collinear with the center axis of the tool bar, the influence of the tool tip position, other geometric parameters and cutting parameters of the tool on the output result of the sensing component needs to be considered. In this case, the stress result of the midpoint of the main cutting edge participating in cutting needs to be equivalent to the center axis of the tool bar, and the decoupling algorithm considering the influence of the tool tip position, other geometric parameters and cutting parameters on the self-sensing result is used for decoupling of the sensing signal.

[0061] The working principle of the application is:

[0062] As Figure 2As shown: the first self-perception component alone constitutes a first output unit, including a first self-perception component elastic substrate 301, two resistance value changes with the force of the cutter bar resistance strain gauges 302 and 305, and two resistance value does not change strain gauges (or fixed resistance) 303 and 304. Under the action of the main cutting force alone, the first self-perception component will be subjected to tensile stress, and the resistance value of the strain gauges 302 and 305 will increase under the action of tensile stress, and the resistance value of the strain gauges (or fixed resistance) 303 and 304 remains unchanged. As shown in Figure 6 As shown: the connection mode of the first self-perception component is 302-303-305-304-302, that is, 302 and 303 are connected in series, 305 and 304 are connected in series, and then are connected in parallel to the circuit of the input voltage U0, and 302 and 305 are not adjacent, and 303 and 304 are not adjacent. The resistance value of the resistance strain gauges 302 and 305 increases, resulting in the output voltage U1 changing from 0 to a positive value. Under the action of the cutting resistance alone, the strain gauges 302 and 305 are subjected to compressive stress, and the resistance value decreases, and the resistance value of the strain gauges (or fixed resistance) 303 and 304 remains unchanged, resulting in the output voltage U1 changing from 0 to a negative value. The action of the feed force alone will not affect the output voltage U1.

[0063] As shown in Figure 3 The second self-perception component alone constitutes a second output unit, including a second self-perception component elastic substrate 401, two resistance value changes with the force of the cutter bar resistance strain gauges 402 and 405, and two resistance value does not change strain gauges (or fixed resistance) 403 and 404. Under the action of the feed force alone, the second self-perception component will be subjected to tensile stress, and the resistance value of the strain gauges 402 and 405 will increase under the action of tensile stress, and the resistance value of the strain gauges (or fixed resistance) 403 and 404 remains unchanged. As shown in Figure 7 As shown: the connection mode of the second self-perception component is 402-403-405-404-402, that is, 402 and 403 are connected in series, 405 and 404 are connected in series, and then are connected in parallel to the circuit of the input voltage U0, and 402 and 405 are not adjacent, and 403 and 404 are not adjacent. The resistance value of the resistance strain gauges 402 and 405 increases, resulting in the output voltage U2 changing from 0 to a positive value. Under the action of the cutting resistance alone, the strain gauges 402 and 405 are subjected to compressive stress, and the resistance value decreases, and the resistance value of the strain gauges (or fixed resistance) 403 and 404 remains unchanged, resulting in the output voltage U2 changing from 0 to a negative value. The action of the main cutting force alone will not affect the output voltage U2.

[0064] As shown in Figure 4As shown: the third self-perception component alone constitutes the third output unit, including the third self-perception component elastic substrate 501, two resistance strain gauges 502 and 505 whose resistance values change with the force of the cutter bar, and two strain gauges (or fixed resistors) 503 and 504 whose resistance values do not change. Under the independent action of the main cutting force, the third self-perception component will be subjected to compressive stress, and under the action of the compressive stress, the resistance values of the strain gauges 502 and 505 become smaller, and the resistance values of the strain gauges (or fixed resistors) 503 and 504 remain unchanged. As shown: Figure 8 As shown: the connection mode of the third self-perception component is 502-503-505-504-502, that is, 502 and 503 are connected in series, 505 and 504 are connected in series, and then are connected in parallel to the circuit of the input voltage U0, and 502 and 505 are not adjacent, and 503 and 504 are not adjacent. The resistance values of the resistance strain gauges 502 and 505 become smaller, resulting in that the output voltage U3 changes from 0 to a negative value. Under the independent action of the cutting resistance, the strain gauges 502 and 505 are subjected to compressive stress, and the resistance values become smaller, and the resistance values of the strain gauges (or fixed resistors) 503 and 504 continue to remain unchanged, resulting in that the output voltage U3 changes from 0 to a negative value. The independent action of the feed force has no effect on the output voltage U3.

[0065] As shown: Figure 5 The fourth self-perception component alone constitutes the third output unit, including the fourth self-perception component elastic substrate 601, two resistance strain gauges 602 and 605 whose resistance values change with the force of the cutter bar, and two strain gauges (or fixed resistors) 603 and 604 whose resistance values do not change. Under the independent action of the feed force, the fourth self-perception component will be subjected to compressive stress, and under the action of the compressive stress, the resistance values of the strain gauges 602 and 605 become smaller, and the resistance values of the strain gauges (or fixed resistors) 603 and 604 remain unchanged. As shown: Figure 9 As shown: the connection mode of the third self-perception component is 602-603-605-604-602, that is, 602 and 603 are connected in series, 605 and 604 are connected in series, and then are connected in parallel to the circuit of the input voltage U0, and 602 and 605 are not adjacent, and 603 and 604 are not adjacent. The resistance values of the resistance strain gauges 602 and 605 become smaller, resulting in that the output voltage U4 changes from 0 to a negative value. Under the independent action of the cutting resistance, the strain gauges 602 and 605 are subjected to compressive stress, and the resistance values become smaller, and the resistance values of the strain gauges (or fixed resistors) 603 and 604 continue to remain unchanged, resulting in that the output voltage U4 changes from 0 to a negative value. The independent action of the main cutting force has no effect on the output voltage U4.

[0066] Under the single action of main cutting force, U1 and U3 are equal in size and opposite in sign; under the single action of feed force, U2 and U4 are equal in size and opposite in sign. But in the actual working process of the tool, it is subjected to main cutting force, feed force and cutting resistance at the same time, and the forces in three directions are coupled with each other. Therefore, the output voltage of the self-sensing component collected by the data acquisition card cannot be directly used to calibrate the three-direction cutting force, and the signal needs to be decoupled first before the cutting force is calibrated.

[0067] As shown in Figure 11 : the process diagram of the tool stress position converted to the tool bar spindle position, which is also the principle diagram of the decoupling algorithm optimization considering the position of the tool tip.

[0068] As shown in Figure 12 : the geometric position diagram of the tool cutting process, which is also the principle diagram of the decoupling algorithm optimization considering the geometric parameters and cutting parameters.

[0069]

[0070] The solution is:

[0071]

Claims

1. A cutting force self-sensing turning tool system, characterized by, The tool bar tail (1), the groove (2), the tool head (7), the blade (8) and the blade groove (9) are included. The tool bar tail (1) is connected with the tool head (7) through a tool bar, the tool bar is a flexible square beam, the tool head (7) is partially provided with the blade groove (9), the blade (8) is arranged in the blade groove (9), four surfaces of the tool bar close to the tool head (7) are provided with four grooves (2) which are completely same in structure, the groove (2) is a sensing part of the self-sensing turning tool system, and the self-sensing assembly is fixed and integrated on the four surfaces of the groove (2). Four sets of self-sensing component structure performance parameters are same, the self-sensing component includes an elastic substrate and two resistance strain gauges and two fixed resistors, in each set of self-sensing component structure, half-bridge direct current circuit is selected as the measuring circuit of strain gauge, the bridge includes four pure resistance bridge arms, wherein the tension and compression working direction of the resistance strain gauge is consistent with the cutting resistance direction of the tool bar, U o is power voltage, U is output voltage; wherein R1 and R4 are resistance strain gauges, which change with the change of tool bar strain, the tool bar is in tension as positive strain, the strain gauge is also in tension, causing the resistance value of the strain gauge to increase; on the contrary, the tool bar is in compression as negative strain, the strain gauge is also in compression with the tool bar, causing the resistance value of the resistance strain gauge to decrease, R2 and R3 are fixed values; when the self-sensing component is strained, causing the resistance value to change ΔR1, ΔR4 R1→R1+ΔR1, R4→R4+ΔR4, the balance state of the bridge is destroyed, voltage is generated, the form of bridge output voltage is: Two resistance strain gauges and two fixed resistors are integrated on the same surface of a rectangular elastic substrate to form a half-bridge differential bridge circuit, which not only eliminates the non-linear error, but also compensates the temperature error.

2. A cutting force self-sensing turning tool system according to claim 1, characterized in that The blade (8) is fixed in the blade groove (9) through the fastening screw (10); the self-sensing assembly comprises a first self-sensing assembly (3), a second self-sensing assembly (4), a third self-sensing assembly (5) and a fourth self-sensing assembly (6).

3. A cutting force self-sensing turning tool system according to claim 2, characterized in that The four self-sensing assemblies are completely same, work independently and do not affect each other.

4. A cutting force self-sensing turning tool system according to claim 1, characterized in that, The voltage signal output by the self-sensing assembly is first amplified by a signal amplifier, then collected by a data acquisition card and transmitted to a computer system, the computer uses a labview software to build a data conversion platform according to a decoupling algorithm, and converts the voltage signal into a three-way cutting force signal. The decoupling algorithm accurately converts four voltage signals output by the self-sensing system of the turning tool in various cutting states into real-time cutting force signals.

5. A cutting force self-sensing turning tool system according to claim 1, characterized in that, The turning tool blade (8) adopts a indexable blade.

6. Use of a cutting force self-sensing turning tool system according to any of claims 1-5, characterized in that, The method comprises the following steps: If the self-sensing precision of the cutting force self-sensing turning tool system is low, and the error caused by the position of the tool tip is not considered, the method comprises the following steps: In the formula, F f , F p , F c respectively are the feed force, the cutting resistance and the main cutting force, U1, U2, U3, U4 respectively are the output voltages of the four sets of self-sensing components; K X , K Y , K Z respectively are the sensitivities of the groove self-sensing components in the feed force, the cutting resistance and the main cutting force three directions, and are obtained by the following formula: In the formula, U0 is the input voltage of the self-sensing assembly, K0 is the sensitivity coefficient of a single resistance wire in the self-sensing assembly, l is the total length of the resistance wire, L is the total length of the tool bar, y1 and y2 are the distances from the proximal end and the distal end of the groove to the clamping position of the tool bar tail, E is the elastic modulus of the tool bar, A and A' are the cross-sectional areas of the tool bar tail and the groove part, a, b, a' and b' are the lengths of the cross sections of the tool bar tail and the groove part in the feed direction and the main cutting force direction, and K0 can be obtained by the following formula: K0 = (1 + 2μ × λE) In the formula, E is the elastic modulus of the resistance wire material, λ is the piezoresistive coefficient, which is related to the material properties, and μ is the Poisson's ratio of the resistance wire material. If the self-sensing precision of the cutting force self-sensing turning tool system is high, the error caused by the position of the tool tip needs to be considered, and the method comprises the following steps: where c and d are the distances of the tool tip from the center axis of the tool bar in the direction of the main cutting force and the feed force, respectively, K X , K Y , K Z are the sensitivity coefficients of the sensitive parts of the tool bar in the X (feed force direction), Y (cutting resistance direction), and Z (main cutting force direction), respectively, U1, U2, U3, U4 are the output voltages of the four sets of self-sensing components, F f , F p , F c are the feed force, cutting resistance, and main cutting force, respectively. If the self-sensing precision of the cutting force self-sensing turning tool system is very high, not only the error caused by the position of the tool tip needs to be considered, but also the errors caused by the tool geometric parameters and the cutting parameters need to be considered, and the method comprises the following steps: where c and d are the distances from the tool tip to the center axis of the tool bar in the direction of the main cutting force and the feed force, respectively, K X , K Y , K Z are the sensitivity coefficients of the sensitive parts of the tool bar in the X (feed force direction), Y (cutting resistance direction), and Z (main cutting force direction), respectively, U1, U2, U3, U4 are the output voltages of the four sets of self-sensing components, F f , F p , F c are the feed force, cutting resistance, and main cutting force, respectively, a p and γ0 are the relief angle and the rake angle of the tool, respectively.

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