CN106969696B - Wire locator, absolute positioning system, absolute positioning method and calibration method - Google Patents

Abstract

The application discloses a wire locator, an absolute positioning system, an absolute positioning method and a calibration method. The wire locator of the present application includes a spherical housing, an electrode plate group and a base, and a wire channel is opened on the axis of the spherical housing; the electrode plate group is composed of four elongated electrode plates of equal size. The channel direction is installed in the wire channel, and the four electrode plates are arranged in parallel and mirror-image symmetrically on the upper, lower, left, and right sides of the axis of the spherical shell. The symmetrical planes of the upper and lower electrode plates are perpendicular to the symmetrical planes of the left and right electrode plates, and two The intersection line of the symmetrical plane coincides with the axis of the spherical shell; the spherical shell is movably installed on the base, and the spherical shell can rotate along the axis on which the thread passage is opened on the base. The wire locator of the present application uses four electrode plates to relatively locate the metal wire loaded with radio frequency signals, and then measures the spatial coordinates of the spherical shell to determine the absolute position of the spherical shell to achieve absolute positioning of the wire.

Description

Wire locator, absolute positioning system, absolute positioning method and calibration method

technical field

The present application relates to the field of wire positioning equipment, in particular to a wire positioning instrument, an absolute positioning system, an absolute positioning method and a calibration method.

Background technique

At present, wires are more and more widely used in ultra-high precision measurement, but the positioning accuracy of wires has not improved. Because the silk thread is small and soft, even a small force will affect the measurement accuracy, so it is impossible to obtain high measurement accuracy by using the contact measurement method; optical measurement instruments such as theodolite and total station need to be aimed at the same measurement point in order to calculate For the three-dimensional position in space, it is difficult to measure the same point for the silk thread with no difference in the length direction, so it is impossible to obtain high measurement accuracy.

Several existing wire locating devices include a photoelectric locator, an image-type wire locator, a capacitive wire locator and a wire displacement monitor.

Among them, the photoelectric locator is used in the Linac Coherent Light Source (LCLS) project of the famous Stanford Linear Accelerator Center (SLAC) in the United States. designed for the relationship. The locator uses a laser diode as the light source and a four-quadrant PSD as the sensor; because the size of the light source of the laser diode is much larger than the diameter of the wire, the designer cleverly uses a slit with a size of about 1/5 of the diameter of the wire as an optical gate to subdivide the signal , thereby increasing the accuracy. The positional relationship between the slit relative to the external reference of the locator is obtained by precise calibration with a three-coordinate measuring machine, and the absolute positioning accuracy of the silk thread can reach 30 microns. When the wire moves, the slit must be aligned with the wire to measure, so the measurement is time-consuming and dynamic observation cannot be performed.

The image-based wire locator, mainly represented by the oWPS product of the open source company, was developed in response to the application requirements of CLIC. It uses two miniature CCD/CMOS cameras as sensors to establish a binocular vision measurement model, and the internal parameters of the cameras and the structural parameters in the model have been precisely calibrated. During measurement, after correcting the image coordinates of the silk thread with the internal parameters of the camera, the three-dimensional position of the thread in the field of view is accurately calculated through the structural parameters. The measurement accuracy can reach 10 microns, and the precision can reach 5 microns. However, due to the limited depth of field of the lens, its measurement range is only 10mm×10mm. Only special wires can be used: vectran. When measuring wires of other materials, especially metal wires, high-precision extraction of wires cannot be achieved due to reflection, which greatly limits its accuracy, and absolute position measurement cannot be performed.

Capacitive wire locator, represented by Fogale's WPS. Its principle is a variable dielectric capacitive sensor. When the wire passes through parallel electrodes, the dielectric constant of the inter-electrode medium will change, thereby converting the position of the wire into a change in capacitance. The measurement accuracy can be improved to 10 microns. But there is no absolute positioning datum, only relative position measurement can be performed.

The wire displacement monitor is a wire positioning device reported by Zhuhongyan et al. in the literature "Design and simulation of a wire position monitor for cryogenic systems in an ADS linac" Chinese Physics C.Vol.38, No.8 (2014). It is used to measure the shrinkage of the equipment position in the cryostat. It is mainly aimed at the relative change of the equipment position during the temperature change of the equipment. The relative position measurement accuracy can reach 30 microns, but without an accurate external reference, the absolute position cannot be measured.

Contents of the invention

The purpose of this application is to provide an improved wire locator, an absolute wire positioning system based on the wire locator, a method for absolute wire positioning using the wire locator, and an error calibration method for absolute wire positioning.

The application adopts the following technical solutions:

One aspect of the present application discloses a wire locator, which includes a spherical housing 11, an electrode plate group and a base 13. A wire channel is opened on the axis of the spherical housing 11 so that the wire passes through; the electrode plate group consists of four independent The four electrode plates 121, 122, 123, 124 are installed in the wire channel along the direction of the wire channel, and the four electrode plates are parallel and symmetrical in mirror image. Arranged on the upper, lower, left, and right sides of the axis of the spherical housing 11, the symmetrical planes of the upper and lower electrode plates are perpendicular to the symmetrical planes of the left and right electrode plates, and the intersection line of the two symmetrical planes coincides with the axis of the spherical housing 11. When in use, the wire Through the area covered by the four electrode plates; the spherical housing 11 is movably installed on the base 13, and the spherical housing 11 can rotate on the base 13 along the axis of opening the wire channel.

It should be noted that, in order to ensure the accuracy of measurement, the spherical shell used in this application is a high-precision sphere, and the base is also high-precision. When the spherical shell rotates on the base, the position of the axis of the spherical shell is different. changing. In an implementation manner, the wire channel is a cylindrical hole, and its axis line coincides with the axis line of the spherical shell, so that the accurate installation of the four electrode plates can be facilitated and ensured.

It should also be noted that the biggest difference between the wire locator of the present application and the existing wire locators is that when the wire locator of the present application is used, a radio frequency signal is loaded on the metal wire. When it is close to the electrode plate, the image charge will be generated on the electrode plate, and the amount of charge is related to the distance between the metal wire and the electrode. Using the two electrode plates placed oppositely, the signals of the two electrode plates can be comprehensively processed, and the metal wire and the electrode can be obtained. The distance between the symmetrical centerlines of the two electrode plates. In this application, four electrode plates are used, and the two-dimensional coordinates of the metal wire relative to the symmetrical center line of the electrode plates can be obtained to realize relative positioning. Combined with the absolute positioning of the spherical shell itself, the absolute positioning of the wire can be realized. What needs to be explained here is that the absolute positioning of the spherical shell can use conventional space coordinate measuring equipment, which will be explained in the subsequent scheme; the absolute positioning of the spherical shell is actually the absolute positioning of the axis of the spherical shell, and in In the design of the wire locator of the present application, the symmetrical center line of the electrode plate coincides with the axis of the spherical housing, so the relative positioning of the metal wire relative to the symmetrical center line of the electrode plate plus the absolute positioning of the spherical housing axis can be Realize the absolute positioning of the wire. However, when installing the electrode plates, it is difficult to ensure that the symmetrical centerlines of the four electrode plates coincide with the axis of the spherical shell. Therefore, the application proposes an error calibration method based on the wire locator of the application, which will also be used in detailed in the subsequent protocol.

Preferably, the outer surface of the spherical housing 11 is provided with twelve V-shaped grooves, and the two reference planes of each V-shaped groove are perpendicular to each other; among the four electrode plates 121, 122, 123, 124, each electrode plate There is a V-shaped groove at each end, and there are eight V-shaped grooves in total. Among the eight V-shaped grooves, the extension direction of the V-shaped groove is perpendicular to the length direction of the corresponding electrode plate, and one of the reference planes of the V-shaped groove is in line with the corresponding electrode plate. The electrode plates are parallel, and the V-shaped grooves at the same end of the four electrode plates 121, 122, 123, 124 are arranged symmetrically along the axis of the spherical housing 11, and the V-shaped grooves at both ends are mirror-symmetrically arranged; the extension direction of the other four V-shaped grooves is consistent with the spherical shape. The axis of the shell 11 is parallel, and four V-shaped grooves are arranged symmetrically and uniformly on the outermost edge of the spherical shell 11 along the axis of the spherical shell 11, and the V-shaped grooves are set between two adjacent electrode plates , the two reference planes of the V-groove are respectively parallel to the two adjacent electrode plates.

Wherein, the outermost edge of the spherical shell 11 is the outermost edge relative to the axis of the spherical shell 11 .

It should be noted that the function of adjusting the datum is, on the one hand, to facilitate the installation of the electrode plate to ensure the accuracy of the installation of the electrode plate; on the other hand, the position of the spherical shell can be adjusted by adjusting the datum. It can be understood that in the wire locator of the present application, the spherical housing rotates along the axis, but is fixed in other orientations; when measuring the wire, sometimes it is necessary to adjust the attitude of the wire locator, that is, other than the rotation of the axis. In other directions, fine-tuning is carried out so that the wire is parallel to the electrode plate, so it is necessary to adjust the reference to change the posture of the spherical shell. It should be noted that the adjustment reference is to adjust the posture of the entire spherical shell and the electrode plate so that the wire is parallel to the electrode plate; is fixed.

It should also be noted that among the twelve V-shaped grooves, the V-shaped grooves at both ends of the electrode plate can not only be used as the installation reference to facilitate the installation of the electrode plate, but also can be used as the yaw angle adjustment reference, while the four with the spherical shell 11 The V-groove parallel to the axis of the vehicle is used as a horizontal adjustment reference to adjust the roll angle and pitch angle. In addition, the spherical shell of the present application has high precision, and can directly measure the spatial position of the spherical body as a reference for spatial installation.

Preferably, high-precision photogrammetric mirrors 151 , 152 , 153 , and 154 are respectively designed at the two openings of the wire channel 14 on the spherical housing 11 .

It should be noted that the role of the high-precision photogrammetry reflection area is designed to coordinate with the non-contact photogrammetry method for absolute positioning of the spherical shell. It can be understood that if the spherical shell is positioned using other methods, such as three-coordinate measurement camera, tracker, etc., you can measure the reflective area without high-precision photogrammetry.

The other side of the application discloses a silk thread absolute positioning system, including a three-coordinate measuring machine and the thread locator of the present application; the silk thread locator 1 is fixedly installed on the six-degree-of-freedom platform 21 of the three-coordinate measuring machine, On the stage 22 of the machine, silk thread support mechanisms 23 and 24 are erected on both sides of the thread positioner 1; during use, the thread 3 passes through the thread positioner 1 through the thread support mechanisms 23 and 24.

It should be noted that, as mentioned above, the silk thread locator of the present application can perform relative positioning of the silk thread, and combined with the absolute positioning of the space coordinates of the silk thread locator itself, the absolute positioning of the silk thread can be realized; In the implementation mode, the silk thread absolute positioning system uses a three-coordinate measuring machine to perform spatial positioning on the silk thread locator. It can be understood that, in addition to the three-coordinate measuring machine, other space coordinate measuring equipment can also be used, which is not specifically limited here.

Another aspect of the present application also discloses a method for absolute positioning of wires, including using the wire locator of the present application to perform positioning and measurement of metal wires according to the following method:

Adjust the position of the wire locator so that when the metal wire passes through the wire locator, it is parallel to the electrode plate;

Load the radio frequency signal on the metal wire, measure the current on the four electrode plates 121, 122, 123, 124, take the axis of the spherical shell 11 as the center, define the direction of the left and right electrode plates as the X axis, and the upper and lower electrode plates The direction is the Y axis, and the position of the metal wire relative to the axis of the spherical shell 11 is obtained according to Formula 1 and Formula 2;

Formula one:

Formula two:

Among them, D _X is the normalized distance from the center in the horizontal direction of the wire, D _Y is the normalized distance from the center in the vertical direction, I _b and I _d are the currents measured by the two electrode plates on the X axis, respectively, and I _a and _Ic are the currents measured by two electrode plates on the Y axis respectively, x is the distance that the metal wire deviates from the axis of the spherical housing 11 in the transverse direction, and y is the distance that the metal wire deviates from the axis of the spherical housing 11 vertically, b is the distance between the electrode plate and the axis of the spherical housing 11, and Φ is the opening angle of the electrode plate relative to the axis of the spherical housing 11;

The absolute position of the spherical housing 11 is measured by space coordinate measuring equipment, and the absolute position of the wire is calculated according to the absolute position of the spherical housing 11 and the position of the wire relative to the axis of the spherical housing 11, thereby realizing absolute positioning of the wire.

Preferably, the spatial coordinate measuring device is a three-coordinate measuring machine, a tracker or a high-precision photogrammetric locator.

Another aspect of the present application also discloses a method of error calibration of the silk thread locator. Using the silk thread locator of the present application, the error calibration of the silk thread locator is carried out according to the following method:

1) Adjust the attitude of the locator so that the electrodes are parallel to the wire, the upper and lower electrodes are parallel to the stage, and the locator reads x1, y1;

2) The position of the metal wire remains unchanged, rotate the locator 180 degrees, and the locator reads x2, y2;

x1=r _x +Δx, _y1 =ry +Δy, after rotating 180 degrees, x2=r _x -Δx, _y2 =ry -Δy; two readings can be subtracted to get Δx=(x1-x2)/2 , Δy=(y1-y2)/2;

Among them, r _x is the distance between the wire and the axis of the spherical shell in the horizontal direction, ry is the distance between the wire and the axis of the spherical shell in the vertical direction, x1, y1 and x2, _y2 are the two measurements of the wire locator relative to the electrode The two-dimensional coordinates of the symmetrical center line of the plate, Δx is the lateral deviation between the symmetrical center line of the electrode plate and the axis of the spherical shell, and Δy is the vertical deviation between the symmetrical center line of the electrode plate and the axis of the spherical shell.

It should be noted that, in one implementation of the present application, adjusting the posture of the locator is mainly performed by adjusting the reference V-shaped groove; while the three-dimensional coordinates of the spherical shell or the locator itself are carried out through other equipment, such as thousand The reference position is measured by a sub-meter, a level or a space coordinate measuring device, and the difference from the required position is obtained, and then the six-degree-of-freedom platform performs corresponding automatic adjustments according to the measured difference. In addition, the electrodes are parallel to the metal wires, mainly to ensure the parallelism of the wires. The horizontal parallelism of the wires is adjusted by the supporting mechanisms at both ends of the wires. The parallelism of the electrode plates is directly guaranteed during assembly. In the error calibration method of the present application, the wire does not need to be directly placed on the symmetrical plane of the electrode, but the current signal can be used to determine the position of the wire and move it to the symmetrical center of the electrode. Due to assembly errors, the electrode symmetry center may not coincide with the sphere center, and the error calibration method is to measure this deviation.

The beneficial effect of this application is:

The wire locator of this application installs four electrode plates in a high-precision spherical shell, uses the four electrode plates to relatively position the metal wire loaded with radio frequency signals, and then measures the spatial coordinates of the spherical shell to determine the spherical shape. The absolute position of the housing, thereby realizing the absolute positioning of the wire. The wire locator of the present application provides a new absolute positioning device with accurate measurement for wire positioning, and is simple and convenient to use and easy to operate.

Description of drawings

Fig. 1 is the structural representation of silk thread locator in the embodiment of the present application;

Fig. 2 is a schematic diagram of the side structure of the spherical housing of the wire locator in the embodiment of the present application;

Fig. 3 is a schematic structural view of the spherical housing of the wire locator in the embodiment of the present application, taken along the wire channel;

Fig. 4 is a schematic structural diagram of the silk absolute positioning system in the embodiment of the present application;

Fig. 5 is the principle analysis diagram of the wire position measurement by the wire locator in the embodiment of the present application;

Fig. 6 is an analysis diagram of error calibration when the wire locator measures the wire position in the embodiment of the present application.

Detailed ways

In the wire locator of this application, four electrode plates are installed on the wire channel, and two pairs of parallel mirror images are arranged symmetrically on the upper, lower, left, and right sides of the axis of the spherical housing. The area surrounded by the four electrode plates is actually the measurement area for wire positioning. ; The axis line of the four electrode plates coincides with the axis of the spherical shell for the convenience of absolute positioning; the four electrode plates can measure the position of the silk wire relative to the axis line of the four electrode plates to achieve relative positioning. For positioning, it is necessary to measure the spatial coordinates of the spherical shell, that is, to obtain the positioning of the axis of the spherical shell. When the axis of the spherical shell coincides with the axes of the four electrode plates, the spatial positioning of the axis of the spherical shell is four The absolute spatial position of the axis line of the electrode plate, plus the position of the wire relative to the axis lines of the four electrode plates, can obtain the absolute spatial position of the wire, and realize the absolute positioning of the wire.

The wire locator of this application, when in use, loads a radio frequency signal to the wire, and when the wire is close to the electrode plate, an image charge will be generated on the electrode plate, and the amount of charge is related to the distance between the metal wire and the electrode, but has no directionality And it is non-linear; if two electrode plates placed opposite to each other are used, the signals of the two electrode plates can be comprehensively processed to obtain the distance between the silk wire and the symmetrical centerline of the two electrode plates, and there is a larger linear area. Therefore, in the wire locator of the present application, the left and right symmetrical electrode plates can locate the position of the wire on the X axis; and the up and down symmetrical electrode plates can locate the position of the wire on the Y axis; four The distance between the wire and the symmetrical center line of the electrode plate can be determined by locating the electrode plate. It should be noted that when measuring the wire positioning, it is necessary to adjust the posture or position of the wire locator first, so that the wire is parallel to the electrode plate, that is, to ensure that the wire is consistent in the depth of the wire channel, and then it can be used for two-dimensional coordinate calibration The distance between the wire and the symmetrical center line of the electrode plate.

The present application will be described in further detail below through specific examples. The following examples only further illustrate the present application, and should not be construed as limiting the present application.

Example

The wire locator of this example, as shown in Figures 1 to 3, comprises a spherical housing 11, an electrode plate group and a base 13, and a wire channel is opened on the axis of the spherical housing 11 so that the wire passes through; the electrode plate group consists of Four independent and equal-sized elongated electrode plates 121, 122, 123, 124 are composed, and the four electrode plates 121, 122, 123, 124 are installed in the thread channel along the direction of the thread channel, and the four electrode plates are parallel to each other The mirror image is symmetrically arranged on the upper, lower, left, and right sides of the axis of the spherical shell 11. The symmetrical planes of the upper and lower electrode plates are perpendicular to the symmetrical planes of the left and right electrode plates, and the intersection line of the two symmetrical planes coincides with the axis of the spherical shell 11. Use At the same time, the wire passes through the area covered by the four electrode plates; the spherical housing 11 is movably installed on the base 13, and the spherical housing 11 can rotate on the base 13 along the axis on which the wire passage is opened. Both the spherical housing 11 and the base 13 of this example are processed with high precision, and when the spherical housing 11 rotates on the base 13, the spatial position of the axis remains unchanged. In addition, in order to adjust the posture of the spherical shell and also for the accurate installation of the electrode plate, an adjustment reference is designed on the spherical casing 11 of this example. By adjusting the reference, the posture of the spherical shell can be changed to keep the wire parallel to the electrode plate . In order to facilitate the spatial positioning of the spherical shell by photogrammetry, in this example, high-precision photogrammetric reflective marks 151, 152, 153, and 154 are respectively designed on the spherical shell 11 at the two openings of the silk channel 14. , as shown in Figure 2, Figure 2 only shows four reflective marks at one of the openings, and a reflective lens is also provided at the corresponding position of the other opening.

The wire locator in this example, when used, the metal wire is parallel to the electrode plate through the wire channel, and the radio frequency signal is loaded on the wire; the positioning principle of the wire locator is that the metal wire loaded with the radio frequency signal will be on the electrode plate Image charge is generated, and the amount of image charge is related to the distance between the metal wire and the electrode plate. Therefore, as shown in Figure 5, define the symmetrical center line of the four electrode plates as the starting point, the upper and lower electrode plates as the Y axis, and the left and right electrode plates as X axis, by detecting the current on the four electrode plates, the position of the metal wire relative to the symmetrical centerline of the electrode plates can be known.

Calculated as follows:

Formula one:

Formula two:

Among them, D _X is the normalized distance from the center in the horizontal direction of the wire, D _Y is the normalized distance from the center in the vertical direction, I _b and I _d are the currents measured by the two electrode plates on the X axis, respectively, and I _a and _Ic are the currents measured by two electrode plates on the Y axis respectively, x is the distance that the metal wire deviates from the axis of the spherical housing 11 in the transverse direction, and y is the distance that the metal wire deviates from the axis of the spherical housing 11 vertically, b is the distance between the electrode plate and the axis of the spherical shell 11 , and Φ is the opening angle of the electrode plate relative to the axis of the spherical shell 11 . In this example, the MX-BPM board card of Bergoz Company is used to process the induced current signal, and the USB7648b analog-to-digital conversion card created by Beijing Zhongtai Research is used for collection.

In this example, for the convenience of use, the readout device of the wire locator is directly connected to the current detection device, and the above formula 1 and formula 2 are written into the software program, so the wire locator can directly give the x and y coordinates of the metal wire Information, the coordinates are the position coordinates of the metal wire relative to the symmetrical center line of the electrode plate.

Based on the wire locator in this example, this example further provides a wire absolute positioning system. In fact, the spatial coordinates of the spherical shell 11 are absolutely positioned using a spatial coordinate measuring device. This example specifically uses a three-coordinate measuring machine. . As shown in Figure 4, the silk thread absolute positioning system of this example includes a three-coordinate measuring machine and a silk thread locator of this example; the silk thread locator 1 is fixedly installed on the six-degree-of-freedom platform 21 of the three-coordinate measuring machine, On the stage 22 of the machine, silk thread support mechanisms 23 and 24 are erected on both sides of the thread positioner 1; during use, the thread 3 passes through the thread positioner 1 through the thread support mechanisms 23 and 24. In this example, a Hexagon Global three-coordinate measuring machine is specifically used; the other components of the three-coordinate measuring machine are the same as those of a general three-coordinate measuring machine, and will not be repeated here.

When in use, use the wire locator in this example to locate the position of the metal wire relative to the symmetrical centerline of the electrode plate, and then measure the spatial coordinates of the axis of the spherical shell with a three-coordinate measuring machine. According to the design of the wire locator, the theoretical The symmetrical center line of the upper electrode plate coincides with the axis of the spherical shell. Therefore, the spatial coordinates of the spherical shell axis measured by the three-coordinate measuring machine are theoretically the spatial coordinates of the symmetrical center line of the electrode plate. Relative to the position coordinates of the symmetrical center line of the electrode plate, the absolute space coordinates of the wire can be obtained, and the absolute positioning of the wire can be realized.

However, considering the installation error, the symmetrical center line of the electrode plate is not completely coincident with the axis of the spherical shell. Therefore, this example provides an error calibration method for the absolute positioning of the wire. The calibration platform adopts the wire absolute positioning system based on the three-coordinate measuring machine in this example.

1) First adjust the posture of the wire locator so that the electrode plates are parallel to the wire, rotate the spherical shell so that the upper and lower electrode plates are parallel to the stage, and the left and right electrode plates are perpendicular to the stage, and adjust the six-degree-of-freedom platform so that The metal wire is on the symmetrical plane of the upper and lower electrode plates, the reading of the wire locator is x1, and at this time, the longitudinal direction y=0, and the three-coordinate measuring machine measures the spatial position S1 of the locator;

2) The position of the metal wire remains unchanged, the spherical housing of the wire locator is rotated 180 degrees, the reading of the wire locator is x2, and the three-coordinate measuring machine measures the spatial position S2 of the locator.

Define r as the distance between the wire and the axis of the spherical shell, and x1 and x2 are the distances between the wire and the symmetrical centerline of the electrode plate measured twice by the wire locator, and Δx is the lateral deviation between the symmetrical centerline of the electrode plate and the axis of the spherical shell, As shown in Figure 6, then x1=r+Δx, x2=r-Δx, and the two readings can be subtracted to obtain Δx=(x1-x2)/2. That is, the lateral deviation between the symmetrical centerline of the electrode plate and the axis of the spherical shell is calculated. The left and right diagrams of Fig. 6 are respectively the measurement diagram of x1 and the measurement diagram of x2 after the spherical shell rotates 180 degrees.

The metal wire can be moved in parallel to obtain different x1 measurement values, and the x2 measurement values measured after the corresponding spherical shell is rotated 180 degrees, and a more accurate Δx value can be obtained through multiple measurements.

Longitudinal deviation is measured in a similar way:

1) First adjust the posture of the wire locator so that the electrode plates are parallel to the wire, rotate the spherical shell so that the upper and lower electrode plates are parallel to the stage, and the left and right electrode plates are perpendicular to the stage, and adjust the six-degree-of-freedom platform so that The metal wire is on the symmetrical plane of the left and right electrode plates, the wire locator reads y1, and at this time, the horizontal direction x=0, and the three-coordinate measuring machine measures the spatial position of the locator;

2) The position of the metal wire remains unchanged, the spherical shell of the wire locator is rotated 180 degrees, the reading of the wire locator is y2, and the three-coordinate measuring machine measures the spatial position of the locator.

Define r as the distance between the wire and the axis of the spherical shell, and y1 and y2 are the distances between the wire and the symmetrical centerline of the electrode plate measured twice by the wire locator, and Δy is the lateral deviation between the symmetrical centerline of the electrode plate and the axis of the spherical shell, Then y1=r+Δy, y2=r-Δy, the two readings can be subtracted to obtain Δy=(y1-y2)/2. That is, the longitudinal deviation between the symmetrical centerline of the electrode plate and the axis of the spherical shell is calculated.

Similarly, y1 and the corresponding y2 measured after the spherical shell is rotated by 180 degrees can be measured multiple times to obtain a more accurate value of Δy.

Alternatively, instead of adjusting the wire to the symmetrical plane of the electrode plate, by measuring x1, y1 for the first time, and x2, y2 after rotating 180 degrees, and subtracting x or y twice by the aforementioned method, calculate the value of Δx and Δy value.

Specifically, for the wire locator of this example, Δx=7.4 microns, and Δy=6.6 microns.

The wire locator of this example can carry out relative positioning to the metal wire, and can also perform absolute positioning. Wherein, the measurement accuracy of the relative positioning is 5 microns, and the accuracy is 5 microns. The measurement accuracy and accuracy of absolute positioning depend on the accuracy of the wire locator and the space coordinate measuring equipment used. In this example, a three-coordinate measuring machine is used to perform absolute positioning on the wire. The measurement accuracy is 6 microns, and the accuracy is 6 microns. .

The above content is a further detailed description of the present application in conjunction with specific implementation modes, and it cannot be considered that the specific implementation of the present application is limited to these descriptions. For those of ordinary skill in the technical field to which this application belongs, some simple deduction or substitutions can be made without departing from the concept of this application, which should be deemed to belong to the protection scope of this application.

Claims (6)

1. A wire locator, characterized in that: comprising a spherical housing (11), an electrode plate group and a base (13), the axis of the spherical housing (11) offers a wire channel (14), so that the wire passes through ; The electrode plate group is composed of four independent and equal-sized elongated electrode plates (121, 122, 123, 124), and the four electrode plates (121, 122, 123, 124) are installed on the wire channel along the direction of the wire channel. Inside, the four electrode plates are arranged in parallel and mirror symmetrically on the up, down, left, and right sides of the axis of the spherical housing (11). The symmetrical planes of the upper and lower two electrode plates are perpendicular to the symmetrical planes of the left and right electrode plates, and the two symmetrical planes The line of intersection coincides with the axis of the spherical housing (11), and during use, the wire passes through the area covered by the four electrode plates; The spherical housing (11) is movably mounted on the base (13), and the spherical housing (11) can rotate on the base (13) along the axis of opening the thread channel; The outer surface of the spherical housing (11) is provided with twelve V-shaped grooves as adjustment references, and the two reference planes of each V-shaped groove are perpendicular to each other; Among the four electrode plates (121, 122, 123, 124), a V-shaped groove is provided at both ends of each electrode plate, and the extending direction of the V-shaped groove is perpendicular to the length direction of the corresponding electrode plate. One of the datum planes is parallel to the corresponding electrode plate, the V-shaped grooves at the same end of the four electrode plates (121, 122, 123, 124) are arranged symmetrically along the axis of the spherical shell (11), and the V-shaped grooves at both ends are arranged symmetrically; The extension direction of the other four V-shaped grooves is parallel to the axis of the spherical shell (11), and the four V-shaped grooves are symmetrically and evenly arranged on the outermost edge of the spherical shell (11) along the axis of the spherical shell (11) , and, the V-shaped groove is arranged between two adjacent electrode plates, and the two reference planes of the V-shaped groove are respectively parallel to the two adjacent electrode plates. 2. The wire locator according to claim 1, characterized in that: on the spherical housing (11), at the two openings of the wire channel (14), high-precision photogrammetric mirrors (151 , 152, 153, 154). 3. A silk thread absolute positioning system, characterized in that: comprise a three-coordinate measuring machine and the silk thread locator described in claim 1 or 2; the silk thread locator (1) is fixedly installed on the six-degree-of-freedom platform ( 21), on the stage (22) of the three-coordinate measuring machine, silk thread support mechanisms (23, 24) are erected on both sides of the thread locator (1); when in use, the thread (3) is supported by the thread Mechanisms (23, 24) pass through the wire locator (1). 4. A silk thread absolute positioning method, characterized in that: comprising adopting the silk thread locator described in claim 1 or 2, carrying out positioning measurement to the metal thread according to the following method, Adjust the position of the wire locator so that when the metal wire passes through the wire locator, it is parallel to the electrode plate; Load the radio frequency signal on the metal wire, measure the current on the four electrode plates (121, 122, 123, 124), take the axis of the spherical shell (11) as the center, define the direction of the left and right electrode plates as the X axis, up and down The direction of the two electrode plates is the Y axis, and according to formula one and formula two, the position of the wire relative to the axis of the spherical housing (11) is obtained; Formula one: Formula two: Among them, D _X is the normalized distance from the center in the horizontal direction of the wire, D _Y is the normalized distance from the center in the vertical direction, I _b and I _d are the currents measured by the two electrode plates on the X axis, respectively, and I _a and _Ic are the currents measured by two electrode plates on the Y axis respectively, x is the distance that the metal wire deviates from the axis of the spherical shell (11) in the lateral direction, and y is the distance that the metal wire deviates from the spherical shell (11) vertically The distance of the axis, b is the distance between the electrode plate and the axis of the spherical housing (11), and Φ is the opening angle of the electrode plate relative to the axis of the spherical housing (11); The absolute position of the spherical shell (11) is measured by space coordinate measuring equipment, and the absolute position of the wire is calculated according to the absolute position of the spherical shell (11) and the position of the wire relative to the axis of the spherical shell (11). , to achieve the absolute positioning of the wire. 5. The absolute positioning method according to claim 4, characterized in that: the space coordinate measuring device is a three-coordinate measuring machine, a tracker or a high-precision photogrammetric positioning device. 6. An error calibration method for a wire locator, characterized in that: the wire locator according to claim 1 or 2 is used for error calibration of the wire locator according to the following method, 1) Adjust the attitude of the locator so that the electrodes are parallel to the wire, the upper and lower electrodes are parallel to the stage, and the locator reads x1, y1; 2) The position of the metal wire remains unchanged, rotate the locator 180 degrees, and the locator reads x2, y2; x1=r _x +Δx, _y1 =ry +Δy, after rotating 180 degrees, x2=r _x -Δx, _y2 =ry -Δy; two readings can be subtracted to get Δx=(x1-x2)/2 , Δy=(y1-y2)/2; Among them, r _x is the distance between the wire and the axis of the spherical shell in the horizontal direction, ry is the distance between the wire and the axis of the spherical shell in the vertical direction, x1, y1 and x2, _y2 are the two measurements of the wire locator relative to the electrode The two-dimensional coordinates of the symmetrical center line of the plate, Δx is the lateral deviation between the symmetrical center line of the electrode plate and the axis of the spherical shell, and Δy is the vertical deviation between the symmetrical center line of the electrode plate and the axis of the spherical shell.