CN116728160A - Cutting force self-sensing turning tool system and method - Google Patents

Abstract

The invention discloses a cutting force self-sensing turning tool system and a method, wherein the cutting force self-sensing turning tool system comprises a tool bar tail part, a groove, a tool bit, a blade and a blade groove; the cutter arbor afterbody passes through the cutter arbor with the tool bit and is connected, and the cutter arbor is elasticity square beam, and the tool bit part is provided with the blade groove, sets up the blade in the blade groove, and four surfaces that the cutter arbor is close to the tool bit part set up four recesses that the structure is identical, and the recess is the perception position of cutting force self-sensing turning tool system, and self-sensing subassembly is fixed to be integrated on four surfaces of recess. The invention has simple structure, only needs to arrange the groove on the cutter bar near the cutter head part, integrates the self-sensing component on the surface of the groove, and has low manufacturing cost and high measuring precision.

Description

A cutting force self-sensing turning tool system and method

Technical field

The invention belongs to the technical field of turning force measurement in turning processing, and specifically relates to a cutting force self-sensing turning tool system and method.

Background technique

Online monitoring of tool cutting status can not only improve processing efficiency and tool utilization, but also prevent serious consequences of damage to fixtures, workpieces, etc. caused by accidents such as tool wear and breakage. Cutting force is one of the basic signals that best reflects cutting process information. It is also the most widely used signal for cutting process monitoring. It is closely related to tool parameters, cutting conditions, tool status, and workpiece surface quality. Therefore, cutting force online state measurement is one of the most direct, effective and common ways to monitor online cutting conditions.

Under the current technical conditions, the measurement of turning force is mainly achieved by using a strain gauge dynamometer or a piezoelectric dynamometer installed on the tool. However, these two force measuring instruments have the following problems due to their own structure and installation methods: For strain gauge force measuring instruments, due to the limitations of the resistance strain gauge pasting process, on the one hand, the measurement accuracy is low; on the other hand, the It is not suitable for use in high temperature environments, thus limiting its scope of application. For piezoelectric force meters, due to the insufficient unidirectionality of the piezoelectric crystal, there is mutual interference when measuring three-dimensional forces and hysteresis when measuring static forces, which results in low measurement accuracy. Both the strain gauge force gauge and the piezoelectric force gauge are relatively large in size, which limits their scope of application.

For existing self-sensing tools, not only are their structures complex, but their measurement accuracy is only improved from two aspects: tool structure and self-sensing component accuracy. There is not much research on the optimization of decoupling algorithms. However, the decoupling algorithm has a huge impact on the accuracy of the self-sensing system. In the existing decoupling algorithm, the force-bearing position of the tool is only defaulted to a point on the entire section of the tool holder or the central axis, and there is no influence on the voltage output of the self-sensing component by the tool tip position, other geometric parameters of the tool, and the cutting parameters of the tool. . Therefore, the existing decoupling algorithm has a huge adverse impact on the self-sensing accuracy of cutting force.

Contents of the invention

In order to overcome the above technical problems, the purpose of the present invention is to provide a cutting force self-sensing turning tool system and method. The system and method have a simple structure and only need to provide a groove on the tool holder close to the tool head, and the manufacturing cost is low. High measurement accuracy.

In order to achieve the above objects, the technical solution adopted by the present invention is:

A cutting force self-sensing turning tool system, including a tool holder tail 1, a groove 2, a tool head 7, a blade 8 and a blade groove 9;

The tail 1 of the cutter holder is connected to the cutter head 7 through a cutter shank. The cutter shank is an elastic square beam. The cutter head 7 is provided with a blade slot 9. The blade 8 is set in the blade slot 9. The cutter shank is close to the four surfaces of the cutter head 7. Four grooves 2 with identical structures are provided. The grooves 2 are the sensing parts of the cutting force self-sensing turning tool system, and the self-sensing components are fixed and integrated on the four surfaces of the grooves 2 .

The fastening screw 10 fixes the blade 8 in the blade groove 9; the self-sensing components include the No. 1 self-sensing component 3, the No. 2 self-sensing component 4, the No. 3 self-sensing component 5, and the No. 4 self-sensing component 6.

The four sets of self-sensing components are exactly the same and work independently without affecting each other.

The voltage signal output by the self-sensing component is first amplified by a signal amplifier, and then collected by a data acquisition card and transmitted to the computer system. Based on the decoupling algorithm, the computer uses labview software to build a data conversion platform to convert the voltage signal into three-dimensional cutting force. Signal;

The decoupling algorithm accurately converts the four voltage signals output by the sensing system of the turning tool under various cutting conditions into real-time cutting force signals.

The turning tool blade 8 adopts an indexable blade.

The four sets of self-sensing components have the same structural performance parameters. The self-sensing components include an elastic substrate and four resistance strain gauges (or two resistance strain gauges and two fixed resistors). Each set of self-sensing components has the same structure. , choose a half-bridge DC circuit as the measurement circuit of the strain gauge. The bridge includes four bridge arms of pure resistance. Among them, the tension and compression working direction of the resistance strain gauge is consistent with the direction of the tool resistance of the tool bar. U ₀ is the power supply voltage. is the output voltage; R ₁ and R ₄ are resistance strain gauges, which change with the change of the tool holder strain (the tool holder is pulled to positive strain, and the strain gauge is pulled accordingly, causing the resistance value of the strain gauge to become larger; conversely, The tool holder is compressed to negative strain, and the strain gauge follows the pressure of the tool holder, causing the resistance value of the resistance strain gauge to become smaller), R ₂ and R ₃ are fixed values; the self-sensing component undergoes strain, causing changes in the resistance value ΔR ₁ , ΔR ₄ When R ₁ →R ₁ +ΔR ₁ and R ₄ →R ₄ +ΔR ₄ , the balance state of the bridge is destroyed and a voltage is generated. The form of the bridge output voltage is:

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

A method of using a cutting force self-sensing turning tool system, including 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 tool tip position on the self-sensing results is not considered, the following steps are included;

In the formula, F _f , F _p , and F _c are the feed force, tool engagement resistance and main cutting force respectively, U ₁ , U ₂ , U ₃ , and U ₄ are the output voltages of four sets of self-induction components respectively; K _X , K _Y and K _Z are the sensitivity of the groove self-sensing component in the three directions of feed force, cutting resistance and main cutting force respectively, and are obtained by the following formula:

In the formula, U ₀ is the input voltage of the self-sensing component, K ₀ 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, y ₁ and y ₂ are the concave The distance between the proximal and distal ends of the groove and the clamping position of the tool holder tail, E is the elastic modulus of the tool holder, A and A′ are respectively the cross-sectional area of the tool holder tail and the cross-sectional area of the tool holder groove, a, b, a ′ and b′ are the lengths of the tool holder tail section and groove section in the direction of feed force and main cutting force respectively. K ₀ can be obtained by the following formula:

K ₀ =(1+2μ+λE)

In the formula, E is the elastic modulus of the resistance wire material, λ is the piezoresistive coefficient, its size is related to the material properties, and 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 tool tip position on the self-sensing results needs to be considered, including the following steps;

In the formula _, c and d are the distances between _the tool tip _and the tool holder center axis in the main cutting force and feed force directions respectively, K The sensitivity coefficients in the three directions (cutting resistance direction) and Z (main cutting force direction), U ₁ , U ₂ , U ₃ , and U ₄ are respectively the output voltages of four sets of self-sensing components, F _f , F _p , F _c are feed force, cutting resistance and main cutting force respectively.

If the self-sensing accuracy of the cutting force self-sensing turning tool system is very high, it is not only necessary to consider the error caused by the tool tip position on the self-sensing results, but also the errors caused by the tool geometric parameters and cutting parameters on the self-sensing results, including Following steps;

In the formula _, c and d are the distances between _the tool tip _and the tool holder center axis in the main cutting force and feed force directions respectively, K The sensitivity coefficients in the three directions (cutting resistance direction) and Z (main cutting force direction), U ₁ , U ₂ , U ₃ , and U ₄ are respectively the output voltages of four sets of self-sensing components, F _f , F _p , F _c are the feed force, tool engagement resistance and main cutting force respectively, a _p and γ ₀ are the back tool engagement amount and tool rake angle respectively.

Beneficial effects of the present invention:

The system structure of the present invention is simple. It only needs to set a groove on the cutter holder near the cutter head, and integrate the self-sensing component on the surface of the groove;

In response to different accuracy requirements, when the method used in the present invention has low self-sensing accuracy requirements, a decoupling algorithm that does not consider the position of the tool tip and other geometric parameters and cutting parameters of the tool can be used. This algorithm is simple and easy to calculate;

When the requirements for self-sensing accuracy are high, there is a method that considers the position of the tool tip. This method is more difficult to calculate than the former, but the accuracy can be significantly improved;

When the requirements for self-sensing accuracy are extremely high, a method that considers the tool tip position and other geometric parameters and cutting parameters of the tool is used. This method is more difficult to calculate than the previous two, but the accuracy is extremely high.

Description of drawings

Figure 1 is a schematic structural diagram of the cutting force self-sensing turning tool system of the present invention.

Figure 2 shows three views of the No. 1 self-sensing component.

Figure 3 is a three-view view of the No. 2 self-sensing component.

Figure 4 is a three-view view of the No. 3 self-sensing component.

Figure 5 shows three views of the No. 4 self-sensing component.

Figure 6 is the bridge circuit diagram of the No. 1 self-sensing component.

Figure 7 is the bridge circuit diagram of the second self-sensing component.

Figure 8 is the bridge circuit diagram of the No. 3 self-sensing component.

Figure 9 is the bridge circuit diagram of the No. 4 self-sensing component.

Figure 10 shows the circuit connection diagram of the self-sensing component.

Figure 11 is a schematic diagram of the process of equivalently converting the stress position from the tool tip to the tool holder axis.

Figure 12 is a schematic diagram of the cutting geometric position of the tool.

Figure 13 is the front view and top view of the cutting force self-sensing tool.

In the picture: 1-the end of the tool holder; 2-the groove; 3-the self-sensing component No. 1; 4-the self-sensing component No. 2; 5-the self-sensing component No. 3; 6-the self-sensing component No. 4; 7-the cutter head ; 8-blade; 9-blade slot; 10-fastening screw; 301-No. 1 self-sensing component elastic substrate; 302-No. 1 self-sensing component No. 1 strain gauge; 303-No. 1 self-sensing component No. 2 Strain gauge (or fixed resistor); 304-No. 3 strain gauge (or fixed resistor) of No. 1 self-sensing component; 305-No. 4 strain gauge of No. 1 self-sensing component; 401-No. 2 self-sensing component elastic substrate; 402-No. 1 strain gauge of No. 2 self-sensing component; 403-No. 2 strain gauge (or fixed resistor) of No. 2 self-sensing component; 404-No. 3 strain gauge (or fixed resistor) of No. 2 self-sensing component; 405 - No. 4 strain gauge of No. 2 self-sensing component; 501 - No. 3 elastic substrate of self-sensing component; 502 - No. 1 strain gauge of No. 3 self-sensing component; 503 - No. 2 strain gauge of No. 3 self-sensing component (or Fixed resistance); 504-No. 3 strain gauge (or fixed resistor) of the No. 3 self-sensing component; 505-No. 4 strain gauge of the No. 3 self-sensing component 601-No. 4 self-sensing component elastic substrate; 602-No. 4 self-sensing component No. 1 strain gauge of the sensing component; 603-No. 2 strain gauge (or fixed resistor) of the No. 4 self-sensing component; 604-No. 3 strain gauge (or fixed resistor) of the No. 4 self-sensing component; 605-No. 4 self-sensing component Component No. 4 strain gauge.

Detailed ways

The present invention will be further described in detail below in conjunction with the accompanying drawings.

Example 1

As shown in Figures 1 to 13: 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 Blade 8.

Among them, the tool holder is an elastic square beam, and the cutter head 7 is provided with a blade slot 9. The fastening screw 10 fixes the blade 8 in the blade slot 9; the four surfaces of the cutter shank close to the cutter head 7 are provided with four identical structures. Groove 2 is the sensing part of the cutting force self-sensing turning tool system. Four sets of self-sensing components are fixed and integrated on the four surfaces of groove 2. The decoupling algorithm accurately converts the four voltage signals output by the sensing system of the turning tool under various cutting conditions into real-time cutting force signals.

The elastic material of the entire tool holder is 40Cr or 42CrMo.

Referring to Figure 1, the cutter head 7 is provided with a blade slot 9 for installing a blade 8. The blade 8 is installed in the blade slot 9 through a fastening screw 10. The installed blade 8 is an indexable blade. A groove 2 is provided near the cutter head 7 of the tool holder, and four self-sensing components are installed on the four surfaces of the groove 2 . The four sets of self-sensing components have the same structural performance parameters. They all include an elastic substrate and four resistance strain grids. A half-bridge DC circuit is selected as the measurement circuit of the strain gauge. The structure of the DC bridge circuit is shown in Figure 3. Figure 4 shows the resistance. Specific location and connection diagram. The bridge includes four purely resistive bridge arms, U ₀ is the supply voltage, and U is the output voltage. Among them, R ₁ and R ₄ are resistance strain gauges, which change with the change of tool holder strain, and R ₂ and R ₃ are fixed values. When the self-sensing component undergoes strain, causing changes in resistance values ΔR ₁ and ΔR ₄ (R ₁ →R ₁ +ΔR ₁ , R ₄ →R ₄ +ΔR ₄ ), the balance state of the bridge is destroyed and a voltage output is generated.

If the accuracy requirements are not high during the cutting process of the tool, there is no need to consider the impact of the tool tip position on the output results of the sensing component, or when the tool tip is located at a point on the central axis of the tool holder, the self-sensing results caused by the tool tip position are not considered. The decoupling algorithm can decouple the sensing signals.

If the accuracy requirements are high during tool cutting, and the tool tip position is not collinear with the tool holder center axis, the impact of the tool tip position on the output results of the sensing component needs to be considered. In this case, the tool tip needs to be moved The force result is equivalently transformed to the center axis of the tool holder. At this time, a decoupling algorithm that considers the position of the tool tip on the self-sensing result needs to be used to decouple the sensing signal.

If the accuracy requirements are extremely high during the cutting process of the tool, and the tool tip position is not collinear with the tool holder center axis, it is necessary to consider the impact of the tool tip position, other geometric parameters of the tool and cutting parameters on the output results of the sensing component. This kind of In this case, it is necessary to equivalently transform the stress results at the midpoint of the cutting part where the main cutting edge participates into the tool holder center axis. At this time, a decoupling algorithm that considers the tool tip position, other geometric parameters and cutting parameters on the self-sensing results needs to be used. Perform decoupling of sensory signals.

Working principle of the invention:

As shown in Figure 2: The No. 1 self-sensing component alone forms the No. 1 output unit, including the No. 1 self-sensing component elastic substrate 301, two resistance strain gauges 302 and 305 whose resistance changes with the force of the tool holder, and two There are strain gauges (or fixed resistors) 303 and 304 whose resistance value does not change. Under the sole action of the main cutting force, the No. 1 self-sensing component will be subjected to tensile stress. Under the action of the tensile stress, the resistance values of strain gauges 302 and 305 become larger, while the resistance values of strain gauges (or fixed resistors) 303 and 304 remain unchanged. constant. As shown in Figure 6: The connection mode of the No. 1 self-sensing 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 connected in parallel to the circuit with input voltage dimension U ₀ , and 302 and 305 are not adjacent, and 303 and 304 are not adjacent. The resistance values of the resistance strain gauges 302 and 305 become larger, causing the output voltage U ₁ to change from 0 to a positive value. Under the sole action of the knife resistance, the strain gauges 302 and 305 are subjected to compressive stress, and the resistance value becomes smaller. The resistance values of the strain gauges (or fixed resistors) 303 and 304 continue to remain unchanged, causing the output voltage _U1 to change from 0 to negative. value. The feed force alone has no influence on the output voltage _U1 .

As shown in Figure 3: The No. 2 self-sensing component alone forms the No. 2 output unit, including the No. 2 self-sensing component elastic substrate 401, two resistance strain gauges 402 and 405 whose resistance changes with the force of the tool holder, and two There are strain gauges (or fixed resistors) 403 and 404 whose resistance value does not change. Under the action of feed force alone, the No. 2 self-sensing component will be subjected to tensile stress. Under the action of tensile stress, the resistance values of strain gauges 402 and 405 become larger, while the resistance values of strain gauges (or fixed resistors) 403 and 404 remain unchanged. Change. As shown in Figure 7: The connection mode of the second self-sensing 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 connected in parallel to the circuit with input voltage dimension U ₀ , and 402 and 405 are not adjacent, and 403 and 404 are not adjacent. The resistance values of the resistance strain gauges 402 and 405 become larger, causing the output voltage U ₂ to change from 0 to a positive value. Under the sole action of the knife resistance, the strain gauges 402 and 405 are subjected to compressive stress, and the resistance value becomes smaller. The resistance values of the strain gauges (or fixed resistors) 403 and 404 continue to remain unchanged, causing the output voltage _U2 to change from 0 to negative. value. The main cutting force alone has no influence on the output voltage _U2 .

As shown in Figure 4: The No. 3 self-sensing component alone forms the No. 3 output unit, including the No. 3 self-sensing component elastic substrate 501, two resistance strain gauges 502 and 505 whose resistance changes with the force of the tool holder, and two There are strain gauges (or fixed resistors) 503 and 504 whose resistance value does not change. Under the sole action of the main cutting force, the No. 3 self-sensing component will be subjected to compressive stress. Under the action of compressive stress, the resistance values of strain gauges 502 and 505 become smaller, while the resistance values of strain gauges (or fixed resistors) 503 and 504 remain. constant. As shown in Figure 8: The connection mode of self-sensing component No. 3 is 502-503-505-504-502, that is, 502 and 503 are connected in series, 505 and 504 are connected in series, and then connected in parallel to the circuit with input voltage dimension U ₀ , 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, causing the output voltage U ₃ to change from 0 to a negative value. Under the sole action of the knife resistance, the strain gauges 502 and 505 are subjected to compressive stress, and the resistance value becomes smaller. The resistance values of the strain gauges (or fixed resistors) 503 and 504 continue to remain unchanged, causing the output voltage _U3 to change from 0 to negative. value. The feed force alone has no influence on the output voltage _U3 .

As shown in Figure 5: The No. 4 self-sensing component alone forms the No. 3 output unit, including the No. 4 self-sensing component elastic substrate 601, two resistance strain gauges 602 and 605 whose resistance changes with the force of the tool holder, and two resistance strain gauges 602 and 605. There are strain gauges (or fixed resistors) 603 and 604 whose resistance value does not change. Under the action of feed force alone, the No. 4 self-sensing component will be subjected to compressive stress. Under the action of compressive stress, the resistance values of strain gauges 602 and 605 become smaller, while the resistance values of strain gauges (or fixed resistors) 603 and 604 remain unchanged. Change. As shown in Figure 9: The connection mode of self-sensing component No. 3 is 602-603-605-604-602, that is, 602 and 603 are connected in series, 605 and 604 are connected in series, and then connected in parallel to the circuit with input voltage dimension U ₀ , 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, causing the output voltage U ₄ to change from 0 to a negative value. Under the sole action of the knife resistance, the strain gauges 602 and 605 are subjected to compressive stress, and the resistance value becomes smaller. The resistance values of the strain gauges (or fixed resistors) 603 and 604 continue to remain unchanged, causing the output voltage U ₄ to change from 0 to negative. value. The main cutting force alone has no influence on the output voltage _U4 .

Under the sole action of the main cutting force, U ₁ and U ₃ are equal in size and opposite in sign; under the sole action of the feed force, U ₂ and U ₄ are equal in size and opposite in sign. However, during the actual working process of the tool, it is subject to the main cutting force, feed force and tool resistance at the same time, and the forces in the three directions are coupled with each other. Therefore, the three-dimensional cutting force cannot be directly calibrated with the output voltage of the self-sensing component collected by the data acquisition card. The signal needs to be decoupled first before calibrating the cutting force.

As shown in Figure 11: The process diagram of the equivalent conversion of the tool force position to the tool holder spindle position is also a schematic diagram of the decoupling algorithm optimization considering the tool tip position.

As shown in Figure 12: A schematic diagram of the geometric position of the tool cutting process, which is also a decoupling algorithm optimization principle diagram that considers geometric parameters and cutting parameters. Decoupling principle:

The solution is:

Claims (7)

1. a cutting force self-sensing turning tool system, which is characterized by comprising a tool bar tail (1), a groove (2), a tool bit (7), a blade (8) and a blade groove (9);

the cutter bar tail (1) is connected with the cutter head (7) through the cutter bar, the cutter bar is an elastic square beam, the cutter head (7) is provided with a blade groove (9), a blade (8) is arranged in the blade groove (9), four grooves (2) with identical structures are formed in the four surfaces of the cutter bar, which are close to the cutter head (7), of the cutter bar, the grooves (2) are sensing parts of a cutting force self-sensing turning cutter system, and the self-sensing components are fixedly integrated on the four surfaces of the grooves (2).

2. A cutting force self-sensing turning tool system according to claim 1, characterized in that the tightening screw (10) secures the insert (8) in the insert pocket (9); 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, wherein said four sets of self-sensing assemblies operate identically, independently, and independently of each other.

4. The cutting force self-sensing turning tool system according to claim 1, wherein the voltage signal output by the self-sensing component is amplified by a signal amplifier firstly, then is collected by a data collection card and is transmitted to a computer system, and the computer builds a data conversion platform by labview software according to a decoupling algorithm to convert the voltage signal into a three-way cutting force signal;

the decoupling algorithm accurately converts four voltage signals output by the turning tool in the sensing system under 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 insert (8) employs an indexable insert.

6. The cutting force self-sensing turning tool system according to claim 1, wherein the four self-sensing assemblies have the same structural performance parameters, the self-sensing assemblies comprise an elastic substrate and four resistance strain gages (or two resistance strain gages and two fixed resistors), each self-sensing assembly structure comprises a half-bridge direct current circuit selected as a measuring circuit of the strain gages, and a bridge comprising four pure-resistance bridge arms, wherein the pulling and pressing working directions of the resistance strain gages are consistent with the direction of the resistance of the cutting tool acted by the cutter bar, and U is as follows ₀ The power supply voltage is U, and the output voltage is U; wherein R is ₁ And R is ₄ The resistance strain gauge is changed along with the change of the strain of the cutter bar (the cutter bar is pulled to be positive strain, the strain gauge is pulled to cause the resistance value of the strain gauge to be increased), otherwise, the cutter bar is stressed to be negative strain, the strain gauge is stressed along with the cutter bar to cause the resistance value of the resistance strain gauge to be reduced), R ₂ And R is ₃ Is a fixed value; the self-sensing component is strained to cause a change in resistance ΔR ₁ 、ΔR ₄ R ₁ →R ₁ +ΔR ₁ 、R ₄ →R ₄ +ΔR ₄ When the balance state of the bridge is destroyed, a voltage is generated, and the bridge circuit outputs electricityThe form of the pressure is:

the four resistance strain gages (or the two resistance strain gages and the two fixed resistors) are integrated on the same surface of the rectangular elastic substrate to form a half-bridge differential bridge circuit, so that nonlinear errors are eliminated, and meanwhile, temperature errors can be compensated.

7. A method of using a cutting force self-sensing turning tool system according to any one of claims 1-6, comprising the steps of;

if the requirement on the self-sensing precision of the cutting force self-sensing turning tool system is lower, and errors caused by the cutter point position to the self-sensing result are not considered, the method comprises the following steps;

wherein F is _f 、F _p 、F _c Respectively a feeding force, a cutting resistance and a main cutting force, U ₁ 、U ₂ 、U ₃ 、U ₄ The output voltages of the four sets of self-induction components are respectively; k (K) _X 、K _Y 、K _Z The sensitivity of the groove self-sensing component in the feeding force, the cutting resistance and the main cutting force is obtained by the following formula:

in U ₀ To self-sense the input voltage of the component, K ₀ The sensitivity coefficient of a single resistance wire in the self-sensing component is L is the total length of the resistance wire, L is the total length of a cutter bar, y ₁ And y ₂ The distance between the near end and the far end of the groove and the clamping position of the tail part of the cutter bar is E is the elastic modulus of the cutter bar, A and A ' are the cross section area of the tail part of the cutter bar and the cross section area of the groove part of the cutter bar, a, b, a ' and b ' are the lengths of the cross section of the tail part of the cutter bar and the cross section of the groove part in the feeding force direction and the main cutting force direction respectively, K ₀ The method can be obtained by the following formula:

K ₀ ＝(1+2μ+λE)

wherein E is the elastic modulus of the resistance wire material, lambda is the piezoresistive coefficient, the size of which is related to the material property, mu is the Poisson's ratio of the resistance wire material;

if the requirement on the self-sensing precision of the cutting force self-sensing turning tool system is higher, the error caused by the cutter point position to the self-sensing result is considered, and the method comprises the following steps of;

wherein c and d are distances from the cutter bar central axis in the directions of main cutting force and feeding force, K _X 、K _Y 、K _Z The sensitivity coefficients of the sensitive part of the cutter bar in three directions of X (feeding force direction), Y (cutting resistance direction) and Z (main cutting force direction) are respectively, U ₁ 、U ₂ 、U ₃ 、U ₄ Output voltages of four sets of self-sensing components respectively, F _f 、F _p 、F _c Respectively a feeding force, a cutting resistance and a main cutting force;

if the self-sensing accuracy requirement on the cutting force self-sensing turning tool system is very high, not only the error caused by the tool tip position on the self-sensing result, but also the error caused by the tool geometric parameters and the cutting parameters on the self-sensing result are considered, and the method comprises the following steps of;

wherein c and d are distances from the cutter bar central axis in the directions of main cutting force and feeding force, K _X 、K _Y 、K _Z The sensitivity coefficients of the sensitive part of the cutter bar in three directions of X (feeding force direction), Y (cutting resistance direction) and Z (main cutting force direction) are respectively, U ₁ 、U ₂ 、U ₃ 、U ₄ Output voltages of four sets of self-sensing components respectively, F _f 、F _p 、F _c Respectively a feeding force, a cutting resistance and a main cutting force _p And gamma ₀ The back draft and the front angle of the cutter are respectively.