阅读说明：本技术 一种基于电涡流效应的平面二维位移传感器 (Plane two-dimensional displacement sensor based on eddy current effect ) 是由 武亮 王鑫达 汤其富 陈锡侯 徐是 郑方燕 童鹏 于 2021-01-22 设计创作，主要内容包括：本发明公开了一种基于电涡流效应的平面二维位移传感器,包括动尺和定尺,定尺包括定尺基体和m个按照的矩阵排列的导电金属板,每个导电金属板的长度、宽度都为在X、Y方向上相邻两个导电金属板的中心距都为W；动尺包括动尺基体和四个平面矩形螺旋线圈,四个平面矩形螺旋线圈按照2×2的矩阵排列；每个平面矩形螺旋线圈的长度、宽度都为四个平面矩形螺旋线圈中分别通入同相位的交流激励电信号,当动尺相对定尺在XY平面平行移动时,通过交流电桥将各个平面矩形螺旋线圈的阻抗转换成电信号,经处理后得到动尺相对定尺在X、Y方向的直线位移。其能简化结构、提高适用性,并且减小加工工艺对测量结果的影响。(The invention discloses a plane two-dimensional displacement sensor based on an eddy current effect, which comprises a movable scale and a fixed scale, wherein the fixed scale comprises a fixed scale base body and m fixed scales Each conductive metal plate has a length and a width of The center distance between two adjacent conductive metal plates in the direction X, Y is W; the movable ruler comprises a movable ruler base body and four planar rectangular spiral coils, wherein the four planar rectangular spiral coils are arranged according to a 2 x 2 matrix; each planar rectangular spiral coil has the length and the width of The same-phase alternating current excitation electric signals are respectively introduced into the four plane rectangular spiral coils, and when the movable ruler is opposite to the fixed rulerWhen the XY plane moves in parallel, the impedance of each plane rectangular spiral coil is converted into an electric signal through an alternating current bridge, and the linear displacement of the movable ruler relative to the fixed ruler in the direction X, Y is obtained after processing. The structure can be simplified, the applicability can be improved, and the influence of the processing technology on the measurement result can be reduced.)

1. A plane two-dimensional displacement sensor based on an eddy current effect comprises a movable ruler (1) and a fixed ruler (2), wherein the movable ruler (1) is opposite to and parallel to the fixed ruler (2) and a gap is reserved between the movable ruler and the fixed ruler; the method is characterized in that:

the fixed length (2) comprises a fixed length base body (20) and m conductive metal plates (21) embedded on the fixed length base body, and the conductive metal plates (21) are in the shape of a middleA centrosymmetric pattern of m conductive metal plates (21) in accordance withEach conductive metal plate (21) having a length and a width ofThe center distance between two adjacent conductive metal plates (21) in the X direction is W, and the center distance between two adjacent conductive metal plates (21) in the Y direction is W; wherein, W is the polar distance of the sensor, n is an integer and n is more than or equal to 3, m is an integer which can be divided by n and m is more than or equal to 3 n;

the movable ruler (1) comprises a movable ruler base body (10) and four planar rectangular spiral coils (11) wound on the movable ruler base body (10), wherein the four planar rectangular spiral coils (11) are arranged according to a 2 x 2 matrix; the distance between two adjacent turns of each planar rectangular spiral coil (11) is equal, and the length and the width of each planar rectangular spiral coil (11) are bothThe center distance between two planar rectangular spiral coils (11) in the X direction isThe center distance between two plane rectangular spiral coils (11) in the Y direction isWherein, i is 0,1,2, 3.;

the same alternating current excitation electric signals are respectively introduced into the four planar rectangular spiral coils (11), when the movable ruler (1) moves in parallel relative to the fixed ruler (2) on the XY plane, the impedance of the four planar rectangular spiral coils (11) changes periodically, the impedance of the four planar rectangular spiral coils (11) is converted into four paths of electric signals through an alternating current bridge, and the four paths of electric signals are processed by the signal processing system to obtain the linear displacement of the movable ruler (1) relative to the fixed ruler (2) in the X direction and the linear displacement of the movable ruler in the Y direction.

2. The planar two-dimensional displacement sensor based on the eddy current effect as claimed in claim 1, wherein: the conductive metal plate (21) is square in shape.

3. The planar two-dimensional displacement sensor based on the eddy current effect as claimed in claim 1, wherein: the conductive metal plate (21) is circular in shape.

4. The planar two-dimensional displacement sensor based on the eddy current effect as claimed in claim 1, wherein: the conductive metal plate (21) is diamond-shaped.

5. The two-dimensional displacement sensor based on the eddy current effect according to any one of claims 1 to 4, wherein: the center distance between two planar rectangular spiral coils (11) in the X direction isThe center distance between two plane rectangular spiral coils (11) in the Y direction is

Technical Field

The invention belongs to the field of planar two-dimensional displacement precision measurement, and particularly relates to a planar two-dimensional displacement sensor based on an eddy current effect.

Background

The existing planar two-dimensional precise displacement sensor can be divided into three types according to different principles: the first is an optical two-dimensional displacement sensor, such as a two-dimensional laser encoder, a Heidenhain PP281 type plane grating, a KGM series encoder and the like; the second is a capacitance type two-dimensional displacement sensor, such as a two-dimensional capacitance sensor developed by Bonse, a two-dimensional precise capacitance micro-displacement sensor developed by Rongbi waves and the like; the third is an inductive two-dimensional displacement sensor, such as a two-dimensional translational displacement sensor developed by von and bin, in which a U-shaped iron core and a coil are respectively placed in two directions perpendicular to each other, when an armature performs planar motion above the iron core, the inductance of the coil changes, and is converted into an electric signal proportional to the displacement through a measuring circuit, and then, as a differential inductive two-dimensional displacement sensor developed by Alik, a measuring unit of U-shaped structure differential electromagnetic effect is simultaneously arranged in the X direction and the Y direction to realize two-dimensional displacement measurement, but the measuring range is relatively small and is only 10 mm. The optical sensor technology is quite mature, but the electrical system is more complex and has stronger dependence on the precise engraving technology; in addition, the optical sensor is easily affected by mechanical shaking and vibration, and has poor oil stain dust resistance and impact vibration resistance and higher manufacturing cost; the capacitance dielectric constant of the capacitance sensor part is easily influenced by external environment factors, the protection capability is poor, and the intelligent degree is not high.

CN104677258A discloses a planar two-dimensional displacement sensor, which includes a fixed front surface (equivalent to a fixed ruler) and a movable front surface (equivalent to a movable ruler) arranged in parallel and opposite; the array surface is provided with an array surface base body, and a single-layer or multi-layer identical excitation coil matrix which is connected in series is arranged on the array surface base body; the movable array surface consists of a movable array surface base body and an induction coil arranged on the surface of the movable array surface base body; the excitation coil of the fixed array surface is connected with an alternating current excitation electric signal, and the magnetic field intensity generated on the surface of the fixed array surface is periodically changed along with the change of the two-dimensional position of the plane; when the movable array surface and the fixed array surface move relatively, the amplitude of the induction signal of the induction coil changes respectively, and linear displacement of the movable array surface relative to the fixed array surface in the X direction and the Y direction can be obtained through processing and resolving. The single movable array surface is adopted to convert magnetic signals at different positions of the fixed array surface into electric signals through the electromagnetic induction principle, so that the planar two-dimensional displacement is obtained, and the device has the characteristics of simple structure, low cost, and strong oil and dust resistance and impact vibration capability. But it still has the following problems: (1) the excitation coil matrix on the fixed array surface and the induction coil on the movable array surface both need to lead signal wires, and the excitation coil matrix and the induction coil on the movable array surface can not be used in some occasions and have narrow application range; (2) all the excitation coil matrixes on the array surface form a loop in a parallel-serial mode, alternating current excitation electric signals are introduced, and if a certain excitation coil is damaged, the sensor cannot measure the signals; (3) in order to reduce the magnetic field difference generated by different coils on the fixed array surface, the measurement result is more accurate, and the requirement on the processing technology is higher; (4) the induction coils on the movable array surface are composed of three induction coils with the same size and the same number of turns, and the corresponding signal processing process is matched to determine that if the movable array surface is not completely parallel or has deflection relative to the fixed array surface, the measurement error can be caused, so that the measurement result is inaccurate.

Disclosure of Invention

The invention aims to provide a planar two-dimensional displacement sensor based on an eddy current effect, so that the structure is simplified, the applicability is improved, and the influence of a machining process on a measurement result is reduced.

The invention relates to a plane two-dimensional displacement sensor based on an eddy current effect, which comprises a movable ruler and a fixed ruler, wherein the movable ruler is just parallel to the fixed ruler, and a gap is reserved between the movable ruler and the fixed ruler. The fixed length comprises a fixed length base body and m conductive metal plates and conductive gold plates embedded on the fixed length base bodyThe shape of the metal plate is a centrosymmetric figure, and the m conductive metal plates are arranged according toEach conductive metal plate has a length and a width ofThe center distance between two adjacent conductive metal plates in the X direction is W, and the center distance between two adjacent conductive metal plates in the Y direction is W; wherein, W is the polar distance of the sensor, n is an integer and n is more than or equal to 3, m is an integer which can be divided by n and m is more than or equal to 3 n. The movable ruler comprises a movable ruler base body and four planar rectangular spiral coils wound on the movable ruler base body, wherein the four planar rectangular spiral coils are arranged according to a 2 x 2 matrix; the distance between two adjacent turns of each planar rectangular spiral coil is equal, and the length and the width of each planar rectangular spiral coil are both equalThe center distance between two planar rectangular spiral coils in the X direction isThe center distance between two planar rectangular spiral coils in the Y direction isWherein i is 0,1,2, 3. The center distance between two planar rectangular spiral coils is designed to beThe mutual influence of two adjacent plane rectangular spiral coils which are simultaneously positioned above one conductive metal plate is avoided.

The same alternating current excitation electric signals are respectively introduced into the four planar rectangular spiral coils, and a magnetic field (namely, a magnetic field containing time quantum and space quantum) which changes along with time and moves along with the movement of the movable ruler is generated on the surface of the movable ruler. When the four planar rectangular spiral coils are positioned above the conductive metal plate, the conductive metal plate can generate eddy current magnetismAnd simultaneously, the eddy magnetic field reacts on the four plane rectangular spiral coils, so that the impedance of the four plane rectangular spiral coils is changed. When the movable ruler moves in parallel relative to the fixed ruler in the XY plane, the right-to-face areas of the four planar rectangular spiral coils and the conductive metal plate change along with the displacement change, the impedance of the corresponding four planar rectangular spiral coils changes periodically along with the displacement change, the impedance of the four planar rectangular spiral coils is converted into four paths of electric signals through the alternating current bridge, and the four paths of electric signals are processed by the signal processing system to obtain the linear displacement of the movable ruler relative to the fixed ruler in the X direction and the linear displacement of the movable ruler in the Y direction. One of the processing procedures of the signal processing system may be: four electric signals U output by four alternating current bridges respectively corresponding to the four planar rectangular spiral coils₁、U₂、U₃、U₄Inputting into a signal processing system, adding and subtracting two by two to obtain four calculated values S₁、S₂、S₃、S₄For four way calculation value S₁、S₂、S₃、S₄And performing pairwise division to obtain two tangent functions, and performing arc tangent calculation on the two tangent functions to obtain the linear displacement of the movable ruler relative to the fixed ruler in the X direction and the linear displacement in the Y direction.

Preferably, the conductive metal plate has a square or circular or diamond shape.

Preferably, the two planar rectangular spiral coils have a center-to-center distance in the X direction ofThe center distance between two planar rectangular spiral coils in the Y direction isThe center distance not only prevents two adjacent plane rectangular spiral coils from being simultaneously positioned on a conductive metal plate, but also enables the overall structure size of the movable ruler to be minimum (compared with the movable rulerThe center distance of,In terms of the center-to-center distance, etc.) to maximize the measurement range of the sensor with the same scale size.

Compared with the prior art, the invention has the following effects:

(1) only follow four plane rectangle spiral coil lead signal line of movable ruler, the scale does not lead signal line, and excitation and response are all acted as by four plane rectangle spiral coil, have improved measuring range, have reduced the signal transmission link, and the structure is simpler to the range of application is wider.

(2) The four plane rectangular spiral coils are respectively and independently connected with the same alternating current excitation electric signal by leading signal wires, so that the problem that the sensor cannot measure due to the damage of a single coil is solved, and the measurement reliability and the applicability are improved.

(3) The eddy current grid array is formed by adopting the conductive metal plate in a fixed length mode, the eddy current magnetic field is generated and faded only in the local range corresponding to the four planar rectangular spiral coils, the problem of mutual interference of the magnetic fields does not exist, and the anti-interference capability is improved.

(4) The plane displacement measurement is realized by measuring the impedance of the four plane rectangular spiral coils, so that the difference of magnetic fields generated by a plurality of different coils is avoided, the requirement on the processing technology is reduced, and the influence of the processing technology on the measurement result is reduced.

(5) Four plane rectangular spiral coils are adopted and matched with corresponding signal processing processes, so that errors caused by incomplete parallel of the movable ruler relative to the fixed ruler or deflection of the movable ruler are reduced, and the accuracy of a measuring result is improved.

Drawings

Fig. 1 is a schematic diagram of the relative position relationship between the movable scale and the fixed scale in embodiment 1.

Fig. 2 is a schematic structural view of the movable ruler in embodiment 1.

Fig. 3 is a schematic structural view of the sizing in embodiment 1.

Fig. 4 is a schematic circuit diagram of an ac bridge used in the first planar rectangular spiral coil in example 1.

Detailed Description

The present invention will be described in detail with reference to the accompanying drawings.

Example 1: the planar two-dimensional displacement sensor based on the eddy current effect as shown in fig. 1 to 4 comprises a movable ruler 1 and a fixed ruler 2, wherein the movable ruler 1 is directly parallel to the fixed ruler 2, and a small gap is formed in the vertical direction (i.e. the directly opposite direction).

As shown in fig. 3, the fixed length 2 includes a fixed length substrate 20 and 25 conductive metal plates 21 embedded on the upper surface of the fixed length substrate 20, the fixed length substrate 20 is a non-magnetic and non-conductive insulating material plate, the conductive metal plates 21 are square, and 25 conductive metal plates 21 are embedded on the upper surface of the insulating material plate in a 5 × 5 matrix by using a semiconductor processing technique to form the fixed length 2. Each conductive metal plate 21 has a length ofHas a width ofThe center distance between two adjacent conductive metal plates 21 in the X direction is W, and the center distance between two adjacent conductive metal plates 21 in the Y direction is W; where W is the sensor pole pitch (i.e., the pole pitch in the sensor X direction is W, Y and is also W).

As shown in fig. 2, the movable rule 1 includes a movable rule base 10 and four planar rectangular spiral coils 11 wound around a lower surface of the movable rule base 10. The four planar rectangular spiral coils 11 are arranged in a 2 × 2 matrix; each planar rectangular spiral coil 11 has ten turns, the distance between two adjacent turns is equal, and the length of each planar rectangular spiral coil 11 isHas a width ofThe center distance between two planar rectangular spiral coils 11 in the X direction isTwo plane moments in the Y directionThe center distance of the helical coil 11 is

As shown in fig. 4, three balancing resistors Rs are connected to the first planar rectangular spiral coil 11 to form an ac bridge. Similarly, three balance resistors Rs are connected with the second planar rectangular spiral coil 11 to form an alternating current bridge; three balance resistors Rs are connected with a third plane rectangular spiral coil 11 to form an alternating current bridge; three balancing resistors Rs are connected to the fourth planar rectangular spiral coil 11 to form an ac bridge. One end of the planar rectangular spiral coil 11 is connected with one end of a first balancing resistor Rs, the other end of the planar rectangular spiral coil 11 is connected with one end of a third balancing resistor Rs, one end of a second balancing resistor Rs is connected with the other end of the first balancing resistor Rs, and the other end of the second balancing resistor Rs is connected with the other end of the third balancing resistor Rs; the two ends of an alternating current excitation (voltage) signal e are connected with the connecting part of the planar rectangular spiral coil 11 and the third balance resistor Rs and the connecting part of the second balance resistor Rs and the first balance resistor Rs through leads, and the connecting part of the planar rectangular spiral coil 11 and the first balance resistor Rs and the connecting part of the second balance resistor Rs and the third balance resistor Rs through leads serve as the output end of an alternating current bridge.

The four plane rectangular spiral coils 11 are respectively introduced with an alternating current excitation signal e with the phase of 0, when the movable ruler 1 moves in parallel relative to the fixed ruler 2 on the XY plane,

the AC bridge corresponding to the first planar rectangular spiral coil 11 outputs an electrical signal U reflecting the impedance of the first planar rectangular spiral coil 11₁：

The AC bridge corresponding to the second planar rectangular spiral coil 11 outputs an electric signal U reflecting the impedance of the second planar rectangular spiral coil 11₂：

The AC bridge corresponding to the third planar rectangular spiral coil 11 outputs an electric signal U reflecting the impedance of the third planar rectangular spiral coil 11₃：

The AC bridge corresponding to the fourth planar rectangular spiral coil 11 outputs an electric signal U reflecting the impedance of the fourth planar rectangular spiral coil 11₄：

In the formula: k is a constant coefficient, omega is the angular frequency of the alternating current excitation signal e, t is a time variable, X is the linear displacement of the movable ruler 1 relative to the fixed ruler 2 in the X direction, and Y is the linear displacement of the movable ruler 1 relative to the fixed ruler 2 in the Y direction;

electric signal U₁、U₂、U₃、U₄Input signal processing system, for U₁、U₂、U₃、U₄Adding every two and subtracting every two to obtain:

for four way calculation value S₁、S₂、S₃、S₄And (3) performing a division operation to obtain:

performing arc tangent calculation on the formula (9) and the formula (10) to obtain the linear displacement X of the movable ruler 1 relative to the fixed ruler 2 in the X direction and the linear displacement Y in the Y direction as follows:

example 2: the operation principle and most of the structure of the planar two-dimensional displacement sensor based on the eddy current effect in the embodiment are the same as those of the embodiment 1, and the differences are only that: the conductive metal plate 21 is circular in shape.

Example 3: the operation principle and most of the structure of the planar two-dimensional displacement sensor based on the eddy current effect in the embodiment are the same as those of the embodiment 1, and the differences are only that: the conductive metal plate 21 has a rhombic shape.