In-situ measurement method and device for edge of workpiece cut by wire electric spark cutting

Abstract

The present invention discloses a method and device for in-situ measurement of the edge of a workpiece produced by wire-cut electric discharge machining. The method comprises constructing an in-situ measurement circuit for an inclined wire electrode; controlling a motion system to control a wire electrode to perform contact measurement of the workpiece edge in a preset posture state when the in-situ measurement circuit for the inclined wire electrode is energized, thereby obtaining contact points between the wire electrode and the workpiece; obtaining spatial position information of the contact points using the in-situ measurement method for the inclined wire electrode; and performing an error comparison between the actual workpiece machining shape obtained by fitting the spatial position information and the required workpiece machining shape to obtain error data. If the error data meets the preset machining accuracy requirements, the workpiece machining process is terminated; if not, accuracy compensation is performed. The present invention solves the problem of poor workpiece edge measurement accuracy caused by existing in-situ contact measurement between the wire electrode and the workpiece.

Description

Technical Field

[0001] The present invention relates to the technical field of special processing, and in particular to an in-situ measurement method and device for an edge of an electric spark wire-cut workpiece. Background Art

[0002] Wire EDM is a process of machining parts using the discharge principle of electric sparks. The workpiece is connected to the positive pole of a pulse power supply, and a molybdenum wire or copper wire is used as the cutting wire. The wire is connected to the negative pole of a high-frequency pulse power supply as a tool electrode, and spark discharge is used to cut the machined parts. As a special machining technology, wire EDM is able to break free from the limitations of traditional mechanical force and mechanical energy and process any material of hardness, strength, and brittleness. This technology occupies an important position in the field of mechanical machining due to its strong applicability, high precision, and low cost. It is widely used in industrial fields such as automobiles, machine tool production, and aerospace. When the electrode wire touches the workpiece, a closed circuit is formed between the power supply, the electrode wire, and the workpiece, and a weak current is generated in the circuit. At this time, the position of the electrode wire can be obtained through feedback from the motion system of the machine tool, thereby obtaining the edge position of the workpiece.

[0003] Current methods for contact measurement between wire electrodes and workpieces propose that when the wire electrode touches the workpiece, a closed circuit is formed between the power supply, wire electrode, and workpiece, generating a weak current. Feedback from the machine tool's motion system then provides the wire electrode position, and thus the workpiece edge position. However, the accuracy of the workpiece edge position obtained in this manner is poor. This is because the wire electrode and workpiece are in line contact. If the workpiece edge has excessive surface roughness or uneven surface topography along the wire electrode's axial direction, the line contact measurement result will be based on the most prominent point, making it difficult to reflect the true condition of the workpiece edge. Therefore, a precise in-situ measurement method that can truly reflect the workpiece edge is needed to address the shortcomings of line contact in-situ measurement. Summary of the Invention

[0004] The present invention aims to solve one of the technical problems in the related art at least to a certain extent.

[0005] To this end, the purpose of the present invention is to propose an in-situ measurement method for the edge of an EDM workpiece, based on the research of EDM wire cutting processing with automatic online measurement and precision compensation, to solve the problem of poor workpiece edge measurement accuracy caused by the existing in-situ measurement of the electrode wire and the workpiece line contact.

[0006] Another object of the present invention is to provide an in-situ measurement device for the edge of a wire-cut electric discharge workpiece.

[0007] To achieve the above-mentioned object, the present invention provides, on one hand, a method for in-situ measurement of the edge of a wire-cut electric discharge workpiece, comprising:

[0008] Construct an in-situ measurement circuit for tilted electrode wire;

[0009] The motion system is controlled to control the electrode wire to perform contact measurement on the edge of the workpiece in a preset posture state when the inclined electrode wire in-situ measurement circuit is powered on, so as to obtain a contact point between the electrode wire and the workpiece;

[0010] Obtaining spatial position information of the contact point using an inclined electrode wire in-situ measurement method;

[0011] The actual machining shape of the workpiece obtained by fitting the spatial position information is compared with the required machining shape of the workpiece to obtain error data. If the error data meets the preset machining accuracy requirements, the workpiece machining process is terminated. If not, accuracy compensation is performed.

[0012] To achieve the above object, the present invention provides, on the other hand, an in-situ measurement device for the edge of a wire-cut electric discharge workpiece, comprising:

[0013] Circuit construction module, used to build tilted electrode wire in-situ measurement circuit;

[0014] A contact point measurement module is configured to control the electrode wire to perform contact measurement on the edge of the workpiece in a preset posture state when the inclined electrode wire in-situ measurement circuit is powered by controlling the motion system to obtain a contact point between the electrode wire and the workpiece;

[0015] a position information calculation module, configured to obtain the spatial position information of the contact point using an inclined electrode wire in-situ measurement method;

[0016] The error comparison calculation module is used to compare the actual processing shape of the workpiece obtained by fitting the spatial position information with the required processing shape of the workpiece to obtain error data. If the error data meets the preset processing accuracy requirements, the workpiece processing process is terminated. If not, accuracy compensation is performed.

[0017] The in-situ measurement method and device for the edge of an EDM workpiece in an embodiment of the present invention are based on research on EDM wire cutting processing with automatic online measurement and precision compensation. It proposes to use an inclined electrode wire to touch the edge of the workpiece and monitor the electrical signal to achieve the function of in-situ measurement of the workpiece edge. It can achieve precise measurement of the workpiece edge without removing the workpiece, and can also improve processing efficiency and processing accuracy.

[0018] Additional aspects and advantages of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the description which follows, or may be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0020] Figure 1 Flowchart of an in-situ measurement method for an edge of a wire-cut electric discharge workpiece according to an embodiment of the present invention;

[0021] Figure 2 Schematic diagram of an in-situ measurement device for an inclined electrode wire according to an embodiment of the present invention;

[0022] Figure 3 Schematic diagram of the in-situ measurement principle of the inclined electrode wire according to an embodiment of the present invention;

[0023] Figure 4 A flowchart of wire-cut electric discharge machining with automatic online measurement and precision compensation according to an embodiment of the present invention;

[0024] Figure 5 Schematic diagram of the structure of an in-situ measurement device for the edge of a wire-cut electric discharge workpiece according to an embodiment of the present invention. DETAILED DESCRIPTION

[0025] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments in this application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0026] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0027] The following describes an in-situ measurement method and device for the edge of a wire-cut electric discharge workpiece according to an embodiment of the present invention with reference to the accompanying drawings.

[0028] Figure 1 The present invention is a flowchart of a method for in-situ measurement of the edge of a wire-cut electric discharge workpiece according to an embodiment of the present invention.

[0029] like Figure 1 As shown, the method includes but is not limited to the following steps:

[0030] S1, constructing an in-situ measurement circuit for tilted electrode wire;

[0031] S2, controlling the motion system to control the electrode wire to perform contact measurement on the edge of the workpiece in a preset posture state when the inclined electrode wire in-situ measurement circuit is powered on, to obtain the contact point between the electrode wire and the workpiece;

[0032] S3, using the tilted electrode wire in-situ measurement method to obtain the spatial position information of the contact point;

[0033] S4, using the spatial position information to fit the actual workpiece processing shape obtained by the error comparison with the required workpiece processing shape to obtain error data, if the error data meets the preset processing accuracy requirements, the workpiece processing process is terminated, if not, the accuracy compensation is performed.

[0034] The present invention utilizes an inclined wire electrode to contact the workpiece edge and monitor electrical signals to achieve in-situ measurement of the workpiece edge. The method of the present invention enables precise measurement of the workpiece edge without removing the workpiece, thereby improving machining efficiency and accuracy.

[0035] In one embodiment of the present invention, the device for the inclined electrode wire in-situ measurement method is as follows Figure 2 As shown in (1. electrode wire, 2. contact point, 3. workpiece, 4. upper machine head, 5. lower machine head), by adjusting the electrode wire posture to be non-parallel to the workpiece processing surface, point contact between the electrode wire and the edge of the workpiece is achieved.

[0036] In one embodiment of the present invention, the principle of the tilted wire electrode in-situ measurement method is as follows: Figure 3 As shown. The pulse power supply shunt points are O1 and O2, the contact conductive points between the wire and the electrode wire are Q1 and Q2, and the contact point between the electrode wire and the edge of the workpiece is P. The equivalent resistance of the upper half of the electrode wire is R e1 , the equivalent inductance is L e1 ; The equivalent resistance of the lower half of the electrode wire is R e2 , the equivalent inductance is L e2 ; The equivalent resistance of the upper wire is R w1 , the equivalent inductance is L w1 ; The equivalent resistance of the lower conductor is R w2 , the equivalent inductance is L w2 ; The equivalent contact resistance between the upper conductor and the electrode wire is R c1 , the equivalent contact resistance between the lower conductor and the electrode wire is R c2 ; The length of the electrode wire between the conductive point Q1 and the contact point P is l e1 , the length of the electrode wire between the conductive point Q2 and the contact point P is l e2 , the length of the electrode wire between the conductive points Q1 and Q2 is l e ; The distance between the conductive point Q1 and the upper head is l u , the distance between the conductive point Q2 and the lower head is l d As shown in Table 1:

[0037] Table 1 Symbols and meanings of physical quantities

[0038] Physical quantity symbols meaning <![CDATA[R e1 ]]> Equivalent resistance of the upper half of the electrode wire <![CDATA[R e2 ]]> Equivalent resistance of the lower half of the electrode wire <![CDATA[R w1 ]]> Equivalent resistance of the upper conductor <![CDATA[R w2 ]]> Equivalent resistance of the lower conductor <![CDATA[R c1 ]]> Equivalent contact resistance between upper conductor and electrode wire <![CDATA[R c2 ]]> Equivalent contact resistance between lower conductor and electrode wire <![CDATA[L e1 ]]> Equivalent inductance of the upper half of the electrode wire <![CDATA[L e2 ]]> Equivalent inductance of the lower half of the electrode wire <![CDATA[L w1 ]]> Equivalent inductance of the upper conductor <![CDATA[L w2 ]]> Equivalent inductance of the lower conductor <![CDATA[l e1 ]]> <![CDATA[The length of the electrode wire between the conductive point Q1 and the contact point P]]> <![CDATA[l e2 ]]> <![CDATA[The length of the electrode wire between the conductive point Q2 and the contact point P]]> <![CDATA[l e ]]> <![CDATA[The length of the electrode wire between the conductive points Q1 and Q2]]> <![CDATA[l u ]]> <![CDATA[Distance between the conductive point Q1 and the upper machine head]]> <![CDATA[l d ]]> <![CDATA[Distance between the conductive point Q2 and the lower machine head]]>

[0039] In the upper and lower loops, the voltages between points O1, O2 and P are expressed as

[0040]

[0041]

[0042] According to Kirchhoff's law, we can get

[0043]

[0044] i0(t)=i1(t)+i2(t) (2-2)

[0045] make

[0046] R1=R e1 +R c1 +R w1

[0047] R2=R e2 +R c2 +R w2

[0048] L1=L e1 +L w1

[0049] L2=L e2 +L w2

[0050] R=R1+R2

[0051] L=L1+L2

[0052] Then formula (2-1) can be expressed as

[0053]

[0054] When the initial condition is 0, perform Laplace transform on equations (2-1) and (2-2) to obtain

[0055] R1I1(s)+sL1I1(s)=R2I2(s)+sL2I2(s) (2-4)

[0056] I0(s)=I1(s)+I2(s)(2-5)

[0057] Combining (2-4) and (2-5) we get

[0058]

[0059] The pulse power supply sends a pulse signal, and the current can be expressed as

[0060] i0(t)=a·1(t)

[0061] Performing Laplace transform, we can get

[0062]

[0063] Substituting formula (2-7) into formula (2-6) we can get

[0064]

[0065] Performing the inverse Laplace transform, we can get

[0066]

[0067] The same logic applies

[0068]

[0069] The voltages between OQ1 and OQ2 are

[0070]

[0071]

[0072] The potential difference is

[0073] Δu(t)=u4(t)-u3(t) (2-11)

[0074] The actual device can make the equivalent resistance, equivalent inductance and contact resistance of the upper and lower wires the same by controlling the wires and contact forms, that is,

[0075] R c =R c1 =R c2

[0076] R w =R w1 =R w2

[0077] L w =L w1 =L w2

[0078] From the calculation formula of the resistance and inductance of cylindrical materials, we can know that the resistance and inductance of cylindrical electrode wire are proportional to the length, that is,

[0079] R e =k R l

[0080] L e =k L l

[0081] The potential difference can be expressed as

[0082]

[0083] The in-situ measurement method of the inclined electrode wire needs to monitor the contact position between the electrode wire and the edge of the workpiece. Therefore, it is necessary to record the potential difference at time t0+, which can be expressed as

[0084] Δu(t)| t＝0+ =[(k1+k3)k R +k2k L ](l e2 -l e1 ) (2-13)

[0085] in

[0086] k1=L(R c +R w )

[0087]

[0088] k3=RL w -L(R c +R w )

[0089] In the formula, k is a constant, from which it can be obtained that the potential difference U is proportional to the length difference between the upper and lower sections of the electrode wire.

[0090] Combined with the positions of the upper and lower machine heads, the exact position of the contact point P in space can be obtained, thereby achieving accurate measurement of the workpiece edge.

[0091] The length of the electrode wire between the upper and lower heads can be expressed as

[0092]

[0093] where l u ,l d Indicates the distance between the conductive points Q1, Q2 and the upper and lower machine heads respectively.

[0094] l e1 ,l e2 The following relationship is satisfied:

[0095]

[0096] Among them, k represents the proportional coefficient of the difference in length between the upper and lower sections of the electrode wire and the potential difference

[0097] k=(k1+k3)k R +k2k L

[0098]

[0099] The spatial positions of the lower machine head, contact point, and upper machine head have the following vector relationship:

[0100]

[0101] The spatial coordinates of the contact point can be obtained:

[0102]

[0103] At this point, the exact coordinates of the contact point P (X p ,Y p ,Z p ) has been obtained, realizing the in-situ measurement method of electrode wire tilting in wire EDM.

[0104] Furthermore, through key point selection, key point measurement, key point fitting, and error characterization, the workpiece size, shape and position accuracy are obtained, the processing error is obtained, and automatic compensation correction is performed. The process is as follows Figure 4 shown.

[0105] The in-situ measurement method for the edge of a workpiece cut by wire electric spark cutting according to an embodiment of the present invention solves the problem of poor workpiece edge measurement accuracy caused by the existing in-situ measurement of the electrode wire and the workpiece line contact, thereby achieving precise measurement of the workpiece edge without removing the workpiece, thereby improving processing efficiency and processing accuracy.

[0106] In order to implement the above embodiment, Figure 5 As shown, this embodiment also provides an in-situ measurement device 10 for the edge of a wire-cut electric discharge workpiece. The device 10 includes: a circuit construction module 100 , a contact point measurement module 200 , a position information calculation module 300 and an error comparison calculation module 400 .

[0107] A circuit construction module 100 is used to construct an inclined electrode wire in-situ measurement circuit;

[0108] The contact point measurement module 200 is configured to control the electrode wire to perform contact measurement on the edge of the workpiece in a preset posture state when the tilted electrode wire in-situ measurement circuit is powered by controlling the motion system to obtain the contact point between the electrode wire and the workpiece;

[0109] A position information calculation module 300 is used to obtain the spatial position information of the contact point using an inclined electrode wire in-situ measurement method;

[0110] The error comparison calculation module 400 is used to compare the actual workpiece processing shape obtained by fitting the spatial position information with the required workpiece processing shape to obtain error data. If the error data meets the preset processing accuracy requirements, the workpiece processing process is terminated. If not, accuracy compensation is performed.

[0111] Furthermore, the device 10 also includes a circuit data setting module for presetting the pulse power supply shunt points of the inclined electrode wire in-situ measurement circuit as O1 and O2, the contact conductive points between the wire and the electrode wire as Q1 and Q2, the contact point between the electrode wire and the edge of the workpiece as P, and the equivalent resistance of the upper half of the electrode wire as R e1 , the equivalent inductance is L e1 ; The equivalent resistance of the lower half of the electrode wire is R e2 , the equivalent inductance is L e2 ; The equivalent resistance of the upper wire is R w1 , the equivalent inductance is L w1 ; The equivalent resistance of the lower conductor is R w2 , the equivalent inductance is L w2 ; The equivalent contact resistance between the upper conductor and the electrode wire is R c1 , the equivalent contact resistance between the lower conductor and the electrode wire is R c2 ; The length of the electrode wire between the conductive point Q1 and the contact point P is l e1 , the length of the electrode wire between the conductive point Q2 and the contact point P is l e2 , the length of the electrode wire between the conductive points Q1 and Q2 is l e ; The distance between the conductive point Q1 and the upper head is l u , the distance between the conductive point Q2 and the lower head is l d .

[0112] Furthermore, in the upper and lower loops of the tilted electrode wire in-situ measurement circuit, the voltage between points O1, O2 and point P is expressed as:

[0113]

[0114]

[0115] According to Kirchhoff's law:

[0116]

[0117] i0(t)=i1(t)+i2(t) (2-2)

[0118] make

[0119] R1=R e1 +R c1 +R w1

[0120] R2=R e2 +R c2 +R w2

[0121] L1=L e1 +L w1

[0122] L2=L e2 +L w2

[0123] R=R1+R2

[0124] L=L1+L2

[0125] Then formula (2-1) is expressed as:

[0126]

[0127] When the initial condition is 0, perform Laplace transform on equations (2-1) and (2-2) to obtain:

[0128] R1I1(s)+sL1I1(s)=R2I2(s)+sL2I2(s) (2-4)

[0129] I0(s)=I1(s)+I2(s)(2-5)

[0130] Combining (2-4) and (2-5) we get:

[0131]

[0132] The pulse power supply sends a pulse signal, and the current is expressed as:

[0133] i0(t)=a·1(t)

[0134] Performing Laplace transform, we get:

[0135]

[0136] Substituting formula (2-7) into formula (2-6) yields:

[0137]

[0138] Performing the inverse Laplace transform, we get:

[0139]

[0140] Similarly:

[0141]

[0142] The voltages between OQ1 and OQ2 are:

[0143]

[0144]

[0145] The potential difference is:

[0146] Δu(t)=u4(t)-u3(t)(2-11).

[0147] Furthermore, by controlling the wires and contact forms, the equivalent resistance, equivalent inductance, and contact resistance of the upper and lower wires are made the same, that is:

[0148] R c =R c1 =R c2

[0149] R w =R w1 =R w2

[0150] L w =L w1 =L w2

[0151] Based on the calculation formula of the resistance and inductance of cylindrical materials, the resistance and inductance of cylindrical electrode wire are proportional to the length, that is:

[0152] R e =k R l

[0153] L e =k L l

[0154] The potential difference is then expressed as:

[0155]

[0156] Based on the in-situ measurement method of the inclined electrode wire, the contact position between the electrode wire and the edge of the workpiece is monitored, and the potential difference at time t0+ is recorded, which is expressed as:

[0157] Δu(t)| t＝0+ =[(k1+k3)k R +k2k L ](l e2 -l e1 ) (2-13)

[0158] in

[0159] k1=L(R c +R w )

[0160]

[0161] k3=RL w -L(R c +R w )

[0162] Where k is a constant.

[0163] Furthermore, the exact position of the contact point P in space is obtained based on the position information of the upper and lower heads;

[0164] The length of the electrode wire between the upper and lower heads is expressed as:

[0165]

[0166] where l u ,l d Indicates the distance between the conductive points Q1, Q2 and the upper and lower machine heads respectively;

[0167] l e1 , l e2 The following relationship is satisfied:

[0168]

[0169] Where k represents the proportional coefficient of the length difference between the upper and lower sections of the electrode wire and the potential difference:

[0170] k=(k1+k3)k R +k2k L

[0171]

[0172] The spatial positions of the lower machine head, contact point, and upper machine head have the following vector relationship:

[0173]

[0174] The space coordinates of the contact point are:

[0175]

[0176] The in-situ measurement device for the edge of a workpiece cut by wire electric discharge according to an embodiment of the present invention solves the problem of poor workpiece edge measurement accuracy caused by the existing in-situ measurement of the electrode wire and the workpiece line contact, thereby achieving precise measurement of the workpiece edge without removing the workpiece, thereby improving processing efficiency and processing accuracy.

[0177] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present invention, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0178] In the description of this specification, the reference terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and features of different embodiments or examples without contradiction.

[0179] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A method for in-situ measurement of the edge of a wire-cut electric discharge workpiece, characterized in that: The following steps are involved: Construct an in-situ measurement circuit for tilted electrode wire; The motion system is controlled to control the electrode wire to perform contact measurement on the edge of the workpiece in a preset posture state when the inclined electrode wire in-situ measurement circuit is powered on, so as to obtain a contact point between the electrode wire and the workpiece; Obtaining spatial position information of the contact point using an inclined electrode wire in-situ measurement method; Comparing the actual machining shape of the workpiece obtained by fitting the spatial position information with the required machining shape of the workpiece to obtain error data; if the error data meets the preset machining accuracy requirements, the workpiece machining process is terminated; if not, accuracy compensation is performed; The pulse power shunt points of the tilted wire electrode in-situ measurement circuit are preset as O1 and O2, the contact conductive points between the wire and the wire electrode are Q1 and Q2, the contact point between the wire electrode and the edge of the workpiece is P, and the equivalent resistance of the upper half of the wire electrode is R e1 , the equivalent inductance is L e1 ; The equivalent resistance of the lower half of the electrode wire is R e2 , the equivalent inductance is L e2 ; The equivalent resistance of the upper wire is R w1 , the equivalent inductance is L w1 ; The equivalent resistance of the lower conductor is R w2 , the equivalent inductance is L w2 ; The equivalent contact resistance between the upper conductor and the electrode wire is R c1 , the equivalent contact resistance between the lower conductor and the electrode wire is R c2 ; The length of the electrode wire between the conductive point Q1 and the contact point P is l e1 , the length of the electrode wire between the conductive point Q2 and the contact point P is l e2 , the length of the electrode wire between the conductive points Q1 and Q2 is l e ; The distance between the conductive point Q1 and the upper head is l u , the distance between the conductive point Q2 and the lower head is l d ; In the upper and lower loops of the tilted wire electrode in-situ measurement circuit, the voltages between points O1, O2 and P are expressed as: According to Kirchhoff's law: i0(t)=i1(t)+i2(t) (2-2) make R1=R e1 +R c1 +R w1 R2=R e2 +R c2 +R w2 L1=L e1 +L w1 L2=L e2 +L w2 R=R1+R2 L=L1+L2 Then formula (2-1) is expressed as: When the initial condition is 0, perform Laplace transform on equations (2-1) and (2-2) to obtain: R1I1(s)+sL1I1(s)=R2I2(s)+sL2I2(s) (2-4) I0(s)=I1(s)+I2(s)(2-5) Combining (2-4) and (2-5) we get: The pulse power supply sends a pulse signal, and the current is expressed as: i0(t)=a·1(t) Performing Laplace transform, we get: Substituting formula (2-7) into formula (2-6) yields: Performing the inverse Laplace transform, we get: Similarly: The voltages between OQ1 and OQ2 are: The potential difference is: Δu(t)=u4(t)-u3(t)(2-11); By controlling the conductors and contact forms, the equivalent resistance, equivalent inductance, and contact resistance of the upper and lower conductors are made the same, that is: R c =R c1 =R c2 R w =R w1 =R w2 L w =L w1 =L w2 Based on the calculation formula of the resistance and inductance of cylindrical materials, the resistance and inductance of cylindrical electrode wire are proportional to the length, that is: R e =k R l L e =k L L The potential difference is then expressed as: Based on the in-situ measurement method of the inclined electrode wire, the contact position between the electrode wire and the edge of the workpiece is monitored, and the potential difference at time t0+ is recorded, which is expressed as: in k1=L(R c +R w ) k3=RL w -L(R c +R w ) Where k is a constant; Based on the position information of the upper and lower heads, the accurate position of the contact point P in space is obtained; The length of the electrode wire between the upper and lower heads is expressed as: where l u ,l d Indicates the distance between the conductive points Q1, Q2 and the upper and lower machine heads respectively; l e1 , l e2 The following relationship is satisfied: Where k represents the proportional coefficient of the length difference between the upper and lower sections of the electrode wire and the potential difference: k=(k1+k3)k R +k2k L The spatial positions of the lower machine head, contact point, and upper machine head have the following vector relationship: The space coordinates of the contact point are:

2. An in-situ measurement device for the edge of a wire-cut electric discharge workpiece, characterized in that: include: Circuit construction module, used to build tilted electrode wire in-situ measurement circuit; A contact point measurement module is configured to control the electrode wire to perform contact measurement on the edge of the workpiece in a preset posture state when the inclined electrode wire in-situ measurement circuit is powered by controlling the motion system to obtain a contact point between the electrode wire and the workpiece; a position information calculation module, configured to obtain the spatial position information of the contact point using an inclined electrode wire in-situ measurement method; an error comparison calculation module, configured to compare the actual workpiece machining shape obtained by fitting the spatial position information with the required workpiece machining shape to obtain error data; if the error data meets the preset machining accuracy requirements, the workpiece machining process is terminated; if not, accuracy compensation is performed; The device also includes a circuit data setting module for presetting the pulse power supply shunt points of the inclined electrode wire in-situ measurement circuit as O1 and O2, the contact conductive points between the wire and the electrode wire as Q1 and Q2, the contact point between the electrode wire and the edge of the workpiece as P, and the equivalent resistance of the upper half of the electrode wire as R e1 , the equivalent inductance is L e1 ; The equivalent resistance of the lower half of the electrode wire is R e2 , the equivalent inductance is L e2 ; The equivalent resistance of the upper wire is R w1 , the equivalent inductance is L w1 ; The equivalent resistance of the lower conductor is R w2 , the equivalent inductance is L w2 ; The equivalent contact resistance between the upper conductor and the electrode wire is R c1 , the equivalent contact resistance between the lower conductor and the electrode wire is R c2 ; The length of the electrode wire between the conductive point Q1 and the contact point P is l e1 , the length of the electrode wire between the conductive point Q2 and the contact point P is l e2 , the length of the electrode wire between the conductive points Q1 and Q2 is l e ; The distance between the conductive point Q1 and the upper head is l u , the distance between the conductive point Q2 and the lower head is l d ; In the upper and lower loops of the tilted wire electrode in-situ measurement circuit, the voltages between points O1, O2 and P are expressed as: According to Kirchhoff's law: i0(t)=i1(t)+i2(t) (2-2) make R1=R e1 +R c1 +R w1 R2=R e2 +R c2 +R w2 L1=L e1 +L w1 L2=L e2 +L w2 R=R1+R2 L=L1+L2 Then formula (2-1) is expressed as: When the initial condition is 0, perform Laplace transform on equations (2-1) and (2-2) to obtain: R1I1(s)+sL1I1(s)=R2I2(s)+sL2I2(s) (2-4) I0(s)=I1(s)+I2(s)(2-5) Combining (2-4) and (2-5) we get: The pulse power supply sends a pulse signal, and the current is expressed as: i0(t)=a·1(t) Performing Laplace transform, we get: Substituting formula (2-7) into formula (2-6) yields: Performing the inverse Laplace transform, we get: Similarly: The voltages between OQ1 and OQ2 are: The potential difference is: Δu(t)=u4(t)-u3(t)(2-11); By controlling the conductors and contact forms, the equivalent resistance, equivalent inductance, and contact resistance of the upper and lower conductors are made the same, that is: R c =R c1 =R c2 R w =R w1 =R w2 L w =L w1 =L w2 Based on the calculation formula of the resistance and inductance of cylindrical materials, the resistance and inductance of cylindrical electrode wire are proportional to the length, that is: R e =k R l L e =k L L The potential difference is then expressed as: Based on the in-situ measurement method of the inclined electrode wire, the contact position between the electrode wire and the edge of the workpiece is monitored, and the potential difference at time t0+ is recorded, which is expressed as: in k1=L(R c +R w ) k3=RL w -L(R c +R w ) Where k is a constant; Based on the position information of the upper and lower heads, the accurate position of the contact point P in space is obtained; The length of the electrode wire between the upper and lower heads is expressed as: where l u ,l d Indicates the distance between the conductive points Q1, Q2 and the upper and lower heads respectively; l e1 , l e2 The following relationship is satisfied: Where k represents the proportional coefficient of the length difference between the upper and lower sections of the electrode wire and the potential difference: k=(k1+k3)k R +k2k L The spatial positions of the lower machine head, contact point, and upper machine head have the following vector relationship: The space coordinates of the contact point are:

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