Spliced absolute time grating linear displacement sensor

Abstract

The application discloses a spliced absolute time grating linear displacement sensor, which comprises fixed scales and a moving scale, the fixed scale comprises a fixed scale base body and a coarse machine coupling unit and a fine machine coupling unit, the moving scale comprises a moving scale base body and an exciting unit, a coarse machine induction unit and a fine machine induction unit, there are S fixed scales, and the S fixed scales are spliced in sequence at the head and tail along an X direction to form a fixed scale group; an alternating excitation electric signal is input into the exciting unit; when the moving scale moves in parallel relative to the fixed scale group in a measuring direction, a standing wave signal output on the moving scale can be processed to obtain an absolute linear displacement value; the application can reduce the interference of various electromagnetic waves in the air, realize large-range absolute linear displacement measurement with a measuring range of several meters or even dozens of meters, and has wide application range and high sensitivity.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of precision measurement sensors, and particularly relates to a spliced absolute time grating linear displacement sensor. BACKGROUND

[0002] In recent years, with the vigorous development of manufacturing industry, the demand for high-precision large-scale manufacturing equipment is increasing, and the high-precision large-range absolute linear displacement measurement technology is required to have a range of several meters and high precision, and to realize absolute positioning in a large range without measurement cumulative error.

[0003] The electromagnetic absolute time grating linear displacement sensor, as one of many absolute displacement sensors, has the function of not losing zero point when power failure, can realize high-precision measurement and absolute positioning, and has been widely used in the field of precision displacement measurement. However, the moving scale base of the current electromagnetic absolute time grating linear displacement sensor cannot completely cover the coils on the fixed scale base, resulting in the coupling of the coils on the fixed scale base with various electromagnetic waves in the air, generating high harmonic interference, and it is difficult to realize the manufacturing of a single large-range sensor base due to the limitation of processing technology. SUMMARY

[0004] The purpose of the application is to provide a spliced absolute time grating linear displacement sensor to reduce the interference of various electromagnetic waves in the air and realize large-range absolute linear displacement measurement with a measurement range of several meters or even dozens of meters.

[0005] The spliced absolute time grating linear displacement sensor comprises a fixed scale and a moving scale opposite to the fixed scale in parallel and leaving a gap, the fixed scale comprises a fixed scale base, the moving scale comprises a moving scale base and an induction unit arranged on the moving scale base, the X direction is set as the measurement direction, the Y direction is parallel to the fixed scale base and perpendicular to the X direction, and the Z direction is perpendicular to the direction of the fixed scale base.

[0006] The fixed scale base is provided with a coarse machine coupling unit and a fine machine coupling unit. The coarse machine coupling unit is composed of M independent coarse machine coupling coils arranged in a row along the X direction at equal intervals, and the coarse machine coupling coils are in the shape of a planar square spiral with the starting end connected to the terminal end. The fine machine coupling unit is composed of N independent fine machine coupling coils arranged in another row along the X direction at equal intervals, and the fine machine coupling coils are in the shape of a planar square spiral with the starting end connected to the terminal end. The starting position of the fine machine coupling unit is aligned with the starting position of the coarse machine coupling unit in the Y direction (i.e. the starting position of the first coarse machine coupling coil is aligned with the starting position of the first fine machine coupling coil in the Y direction). Wherein, N*W2=M*W1, W1 represents the pole pitch of the coarse machine coupling unit, W2 represents the pole pitch of the fine machine coupling unit, M and N are co-prime, and M D1 represents the distance between the starting position of the precision coupling unit (i.e. the left end of the outermost turn of the first precision coupling coil) and the left edge of the sizing base in the X direction, and D2 represents the distance between the ending position of the precision coupling unit (i.e. the right end of the outermost turn of the Nth precision coupling coil) and the right edge of the sizing base in the X direction.

[0007] The sizing has S (S≥2), and the S sizings are sequentially spliced in the X direction to form a sizing group.

[0008] The sizing base is further provided with an excitation unit, which is composed of a forward-wound planar rectangular spiral coil and a reverse-wound planar rectangular spiral coil aligned in the Y direction in series. The sensing unit includes a rough machine sensing unit located in the reverse-wound planar rectangular spiral coil and opposite to the rough machine coupling unit, and a precision machine sensing unit located in the forward-wound planar rectangular spiral coil and opposite to the precision machine coupling unit.

[0009] In operation, the sensor is reset, the movable ruler moves relative to the sizing group, an excitation signal (a cosine excitation signal or a sine excitation signal) is input into the excitation unit, an alternating air gap magnetic field is generated, the rough machine coupling unit and the precision machine coupling unit generate an alternating magnetic field (the direction of the alternating magnetic field is opposite to that of the alternating air gap magnetic field generated by the excitation unit) under the action of the alternating air gap magnetic field, the rough machine sensing unit is coupled with the alternating magnetic field to output a rough machine sensing signal, the precision machine sensing unit is coupled with the alternating magnetic field to output a precision machine sensing signal, and the absolute linear displacement value of the movable ruler relative to the sizing is obtained by processing the rough machine sensing signal and the precision machine sensing signal.

[0010] Preferably, the rough machine sensing unit includes a rough machine first sensing coil and a rough machine second sensing coil which are identical in structure, insulated from each other, and staggered in the X direction at the starting end. Preferably, the precision machine sensing unit includes a precision machine first sensing coil and a precision machine second sensing coil which are identical in structure, insulated from each other, and staggered in the X direction at the starting end. The rough machine first sensing coil, the rough machine second sensing coil, the precision machine first sensing coil, and the precision machine second sensing coil are all connected by the via holes between the wire segments arranged on adjacent two layers.

[0011] Preferably, the winding track of the rough machine first sensing coil is a first sine curve and a second sine curve which have the same starting position, an amplitude A, a period W1, a number of periods Q, and a phase difference of 180°. The second wire segment of the rough machine first sensing coil wound in the first sine curve part in the interval is located on the E wiring layer, and the first wire segment of the rough machine first sensing coil wound in the first sine curve part in the interval and the second wire segment of the rough machine first sensing coil wound in the second sine curve part in the interval are located on the D wiring layer. ​The third wire segment wound by the first sinusoidal curve part in the interval is located on the F wiring layer; the along The fifth wire segment wound by the second sinusoidal curve part in the interval is located on the F wiring layer, and the along The fourth wire segment wound by the second sinusoidal curve part in the interval and the along The sixth wire segment wound by the second sinusoidal curve part in the interval is located on the E wiring layer, the starting end of the first seventh wire segment is connected to the starting end of the first tenth wire segment through a via, and the ending end of the Pth ninth wire segment and the ending end of the Pth twelfth wire segment are led as an inductive signal output port of the first fine machine inductive coil, forming a differential structure; wherein j1 takes all integers from 0 to Q-1 in turn, Q≥2, and the E wiring layer is adjacent to the F wiring layer.

[0012] Since the structure of the second coarse machine inductive coil is the same as that of the first coarse machine inductive coil, only the starting end is staggered along the X direction Therefore, the second coarse machine inductive coil also has a first wire segment, a second wire segment, a third wire segment, a fourth wire segment, a fifth wire segment, and a sixth wire segment.

[0013] Preferably, the winding track of the first fine machine inductive coil is a third sinusoidal curve and a fourth sinusoidal curve with the same starting position, an amplitude A, a period W2, a period number P, and a phase difference of 180°; the along The eighth wire segment wound by the third sinusoidal curve part in the interval is located on the E wiring layer, and the along The seventh wire segment wound by the third sinusoidal curve part in the interval and the along The ninth wire segment wound by the third sinusoidal curve part in the interval is located on the F wiring layer; the along The eleventh wire segment wound by the fourth sinusoidal curve part in the interval is located on the F wiring layer, and the along The tenth wire segment wound by the fourth sinusoidal curve part in the interval and the along The twelfth wire segment wound by the fourth sinusoidal curve part in the interval is located on the E wiring layer, the starting end of the first seventh wire segment is connected to the starting end of the first tenth wire segment through a via, and the ending end of the Pth ninth wire segment and the ending end of the Pth twelfth wire segment are led as an inductive signal output port of the first fine machine inductive coil, forming a differential structure; wherein j2 takes all integers from 0 to P-1 in turn, P≥2.

[0014] Since the structure of the second fine machine inductive coil is the same as that of the first fine machine inductive coil, only the starting end is staggered along the X direction Therefore, the second induction coil of the fine machine also has the seventh wire segment, the eighth wire segment, the ninth wire segment, the tenth wire segment, the eleventh wire segment and the twelfth wire segment.

[0015] Preferably, the P, Q, M and N satisfy: Roundup() represents a rounding-up function, so as to ensure the induction signal strength without sacrificing the measurement range.

[0016] Preferably, the length of the outermost turn of the coarse machine coupling coil in the X direction is equal to The width in the Y direction is L1, and 2A≤L1 Preferably, the length of the outermost turn of the coarse machine coupling coil in the X direction is equal to The width in the Y direction is L2, and 2A≤L2

[0017] Preferably, the coarse machine coupling coil and the fine machine coupling coil have two winding modes: the first mode is that the coarse machine coupling coil is wound into a plane square spiral from inside to outside in a counterclockwise direction, and the fine machine coupling coil is wound into a plane square spiral from inside to outside in a counterclockwise direction; the second mode is that the coarse machine coupling coil is wound into a plane square spiral from outside to inside in a clockwise direction, and the fine machine coupling coil is wound into a plane square spiral from outside to inside in a clockwise direction.

[0018] Preferably, the positive winding plane rectangular spiral coil and the reverse winding plane rectangular spiral coil have two winding modes: the first mode is that the positive winding plane rectangular spiral coil is wound in a counterclockwise direction from outside to inside, the reverse winding plane rectangular spiral coil is wound in a clockwise direction from inside to outside, the starting end of the positive winding plane rectangular spiral coil is connected with the ending end of the reverse winding plane rectangular spiral coil, and the ending end of the positive winding plane rectangular spiral coil and the starting end of the reverse winding plane rectangular spiral coil are led as an excitation signal input port; the second mode is that the positive winding plane rectangular spiral coil is wound in a clockwise direction from inside to outside, the reverse winding plane rectangular spiral coil is wound in a counterclockwise direction from outside to inside, the ending end of the positive winding plane rectangular spiral coil is connected with the starting end of the reverse winding plane rectangular spiral coil, and the starting end of the positive winding plane rectangular spiral coil and the ending end of the reverse winding plane rectangular spiral coil are led as an excitation signal input port.

[0019] Preferably, the processing of the coarse machine induction signal and the fine machine induction signal includes the following steps:

[0020] The displacement between the start position of the coupling unit of the precision machine on the i-th scale and the start position of the coupling unit of the precision machine on the (i+1)-th scale is coded as i, i sequentially takes all integers from 1 to S-1, and the displacement between the start position and the end position of the coupling unit of the precision machine on the S-th scale is coded as S.

[0021] The coarse machine induction signal is processed to obtain a phase difference The precision machine induction signal is processed to obtain a phase difference

[0022] The phase difference is converted to obtain a current coarse machine incremental displacement Δx' t The phase difference is converted to obtain a current precision machine incremental displacement Δx t .

[0023] The current coarse machine incremental displacement Δx' t and the current precision machine incremental displacement Δx t are used to perform epipolar positioning to obtain the number of epipolar positions V of the coupling unit of the precision machine through which the moving scale passes on the current scale.

[0024] The current coarse machine incremental displacement Δx' t and the current precision machine incremental displacement Δx t are used to calculate the code K corresponding to the position of the start end of the current precision machine induction unit (i.e. the leftmost end of the first induction coil of the precision machine), wherein 1≤K≤S.

[0025] The formula: x abs =(K-1)*N*W2+V*W2+Δx t is used to calculate the absolute linear displacement value x abs of the moving scale relative to the scale group.

[0026] Preferably, the current coarse machine incremental displacement Δx' t and the current precision machine incremental displacement Δx t are used to calculate the code K corresponding to the position of the start end of the current precision machine induction unit in the following manner:

[0027] If the current displacement difference Δx" t is in the interval [-6, +6], and the last displacement difference Δx" t-1 is in the interval [-6+G N , 6+G N ], then the code K is incremented by 1 (i.e. K=K+1).

[0028] If the current displacement difference Δx" t is in the interval [-6+G N , 6+G Ninside, and the last displacement difference Δx" t-1 If the interval is [-6, +6], then the code K is decremented by 1 (i.e. K = K - 1).

[0029] wherein the initial value of K is equal to 1; when Δx' t ≥ Δx t - 6, Δx" t = Δx' t - Δx t ; when Δx' t < Δx t - 6, Δx" t = W1+ Δx' t - Δx t ; when Δx' t-1 ≥ Δx t-1 - 6, Δx" t-1 = Δx' t-1 - Δx t - 1; when Δx' t-1 < Δx t-1 - 6, Δx' t-1 = W1+ Δx' t-1 - Δx t-1 ; Δx' t-1 represents the last coarse incremental displacement, Δx t-1 represents the last fine incremental displacement, 6 represents the preset error limit, G N represents the distance between the left end of the outermost turn of the Mth coarse coupling coil and the left end of the outermost turn of the Nth fine coupling coil in the X direction, 6, G N are known parameters.

[0030] Preferably, the coarse inductive signal is processed to obtain the phase difference in the following manner:

[0031] The coarse inductive signal V1 output by the first coarse inductive coil is filtered by a first band-pass filter and amplified by a first amplification circuit to obtain a first standing wave signal E1; the coarse inductive signal V2 output by the second coarse inductive coil is filtered by a second band-pass filter and amplified by a second amplification circuit to obtain a second standing wave signal E2.

[0032] The first standing wave signal E1 is multiplied by a modulation signal I1, and then filtered by a first low-pass filter and amplified by a fifth amplification circuit to obtain a first electric signal U1; the second standing wave signal E2 is multiplied by the modulation signal I1, and then filtered by a second low-pass filter and amplified by a sixth amplification circuit to obtain a second electric signal U2.

[0033] The second electric signal U2 is divided by the first electric signal U1, and the arctangent of the division result is obtained to obtain the phase difference

[0034] Preferably, the fine machine induction signal is processed to obtain a phase difference in the following manner:

[0035] The fine machine induction signal V3 output by the first induction coil of the fine machine is filtered through a third band-pass filter and amplified through a third amplification circuit to obtain a third standing wave signal E3; the fine machine induction signal V4 output by the second induction coil of the fine machine is filtered through a fourth band-pass filter and amplified through a fourth amplification circuit to obtain a fourth standing wave signal E4.

[0036] The third standing wave signal E3 is multiplied by the modulation signal I1, and then filtered through a third low-pass filter and amplified through a seventh amplification circuit to obtain a third electric signal U3; the fourth standing wave signal E4 is multiplied by the modulation signal I1, and then filtered through a fourth low-pass filter and amplified through an eighth amplification circuit to obtain a fourth electric signal U4.

[0037] The fourth electric signal U4 is divided by the third electric signal U3, and the arctangent of the division result is obtained to obtain a phase difference

[0038] Compared with the prior art, the present application has the following effects:

[0039] (1) The coarse machine coupling unit is composed of M mutually independent coarse machine coupling coils, and the fine machine coupling unit is composed of N mutually independent fine machine coupling coils, and the coupling of the alternating magnetic field is only within the range of the forward-wound and reverse-wound planar rectangular spiral coils, thereby reducing the high-order harmonic interference caused by the coupling of the coils on the sensor scale that are not covered by the passive scale body with various electromagnetic waves in the air, and improving the measurement accuracy of the sensor.

[0040] (2) A plurality of scales are spliced into a scale group, and a time grating signal processing circuit is used to realize large-range absolute linear displacement measurement, thereby breaking the limitation of the traditional grating scale manufacturing process on the improvement of the range, and having a wide range of application scenarios.

[0041] (3) The excitation signal and the induction signal are processed on the moving scale side, thereby realizing the passive design of the scale and simplifying the structure of the sensor.

[0042] (4) The excitation unit is composed of a forward-wound planar rectangular spiral coil and a reverse-wound planar rectangular spiral coil in series, thereby enhancing the strength of the induction signal and improving the signal-to-noise ratio of the sensor.

[0043] (5) The differential structure of the first coarse machine induction coil makes the induced electromotive force generated by the part of the first coarse machine induction coil winding along the first sinusoidal curve coupling the alternating air gap magnetic field cancel out the induced electromotive force generated by the part of the first coarse machine induction coil winding along the second sinusoidal curve coupling the alternating air gap magnetic field, and the first coarse machine induction coil is only affected by the coarse machine coupling unit. The differential structure of the second coarse machine induction coil makes the induced electromotive force generated by the part of the second coarse machine induction coil winding along the first sinusoidal curve coupling the alternating air gap magnetic field cancel out the induced electromotive force generated by the part of the second coarse machine induction coil winding along the second sinusoidal curve coupling the alternating air gap magnetic field, and the second coarse machine induction coil is only affected by the coarse machine coupling unit. The differential structure of the first fine machine induction coil makes the induced electromotive force generated by the part of the first fine machine induction coil winding along the third sinusoidal curve coupling the alternating air gap magnetic field cancel out the induced electromotive force generated by the part of the first fine machine induction coil winding along the fourth sinusoidal curve coupling the alternating air gap magnetic field, and the first fine machine induction coil is only affected by the fine machine coupling unit. The differential structure of the second fine machine induction coil makes the induced electromotive force generated by the part of the second fine machine induction coil winding along the third sinusoidal curve coupling the alternating air gap magnetic field cancel out the induced electromotive force generated by the part of the second fine machine induction coil winding along the fourth sinusoidal curve coupling the alternating air gap magnetic field, and the second fine machine induction coil is only affected by the fine machine coupling unit. BRIEF DESCRIPTION OF DRAWINGS

[0044] Figure 1 The structure schematic diagram of the moving ruler and the fixed ruler group in the embodiment of the present application.

[0045] Figure 2 The structure schematic diagram of the fixed ruler in the embodiment of the present application.

[0046] Figure 3 The structure schematic diagram of the fixed ruler group in the embodiment of the present application.

[0047] Figure 4 The structure schematic diagram of the excitation unit, the coarse machine induction unit and the fine machine induction unit in the embodiment of the present application.

[0048] Figure 5 The structure schematic diagram of the coarse machine induction unit in the embodiment of the present application.

[0049] Figure 6 The structure schematic diagram of the fine machine induction unit in the embodiment of the present application.

[0050] Figure 7 The signal processing principle block diagram in the embodiment of the present application. DETAILED DESCRIPTION

[0051] As Figures 1 to 7As shown, the spliced absolute time grating linear displacement sensor in the embodiment of the present application includes S fixed scales and moving scales which are parallel to the fixed scales and have a gap (such as 0.4 mm). The X direction is the measurement direction, the Y direction is parallel to the fixed scale and perpendicular to the X direction, and the Z direction is perpendicular to the fixed scale. The S fixed scales are spliced in sequence along the X direction to form a fixed scale group. The S fixed scales are numbered as No. 1 fixed scale, No. 2 fixed scale, …, and No. S fixed scale respectively.

[0052] As shown in FIG. 1, Figures 1 to 4 Each fixed scale includes a fixed scale base 1 (made of insulator material) and a coarse machine coupling unit 3 and a fine machine coupling unit 4 arranged on the upper surface of the fixed scale base 1. The coarse machine coupling unit 3 is composed of M independent coarse machine coupling coils 31 arranged in a row along the X direction at equal intervals. The coarse machine coupling coils 31 are in the shape of planar square spiral and the start end and the end end are connected by a via. The fine machine coupling unit 4 is composed of N independent fine machine coupling coils 41 arranged in another row along the X direction at equal intervals. The fine machine coupling coils 41 are in the shape of planar square spiral and the start end and the end end are connected by a via. The start position of the fine machine coupling unit 4 is aligned with the start position of the coarse machine coupling unit 3 in the Y direction (i.e. the start position of the first coarse machine coupling coil 31 is aligned with the start position of the first fine machine coupling coil 41 in the Y direction). Wherein, N*W2=M*W1, W1 represents the pole pitch of the coarse machine coupling unit, W2 represents the pole pitch of the fine machine coupling unit, M and N are co-prime, and M D1 represents the distance between the start position of the fine machine coupling unit 4 (i.e. the left end of the outermost turn of the first fine machine coupling coil) and the left edge of the fixed scale base 1 in the X direction, and D2 represents the distance between the end position of the fine machine coupling unit 4 (i.e. the right end of the outermost turn of the Nth fine machine coupling coil) and the right edge of the fixed scale base 1 in the X direction. As an example, M=7 and N=20.

[0053] The length of the outermost turn of the coarse machine coupling coil 31 in the X direction is equal to The width in the Y direction is L1, and 2A≤L1 The length of the outermost turn of the fine machine coupling coil 41 in the X direction is equal to The width in the Y direction is L2, and 2A≤L2 As an example, L1=L2=2A.

[0054] In some embodiments, the coarse machine coupling coil 31 is wound in the shape of planar square spiral from inside to outside in counterclockwise, and the fine machine coupling coil 41 is wound in the shape of planar square spiral from inside to outside in counterclockwise.

[0055] In some embodiments, the coarse machine coupling coil 31 is wound in the shape of planar square spiral from outside to inside in clockwise, and the fine machine coupling coil 41 is wound in the shape of planar square spiral from outside to inside in clockwise.

[0056] As shown in FIG. 1, Figure 1 ,Figures 4 to 6 As shown, the moving scale includes a moving scale base 2 (made of insulating material) and an excitation unit and a sensing unit disposed on the lower surface of the moving scale base 2. The excitation unit is composed of a forward-wound planar rectangular helical coil 71 and a reverse-wound planar rectangular helical coil 72 aligned in the Y direction, connected in series. The sensing unit includes a coarse-machine sensing unit 5 and a fine-machine sensing unit 6. The coarse-machine sensing unit 5 is located inside the reverse-wound planar rectangular helical coil 72 and is directly opposite to the coarse-machine coupling unit 3. The fine-machine sensing unit 6 is located inside the forward-wound planar rectangular helical coil 71 and is directly opposite to the fine-machine coupling unit 4.

[0057] like Figure 5 As shown, the coarse machining induction unit 5 includes components with identical structures, mutually insulated from each other, and whose starting ends are offset along the X direction. The first induction coil 51 and the second induction coil 52 of the roughing machine.

[0058] The winding trajectory of the first induction coil 51 of the roughing mill consists of a first sine curve and a second sine curve, both starting at the same position, with an amplitude of A, a period of W1, a number of periods of Q, and a phase difference of 180°. The second conductor segment 512 (a total of Q segments) wound on the first sine curve portion within the interval is located on the E wiring layer, along the first induction coil 51 of the rough machine. The first conductor segment 511 (a total of Q segments) wound around the first sine curve portion within the interval and along... The third conductor segment 513 (of which there are Q segments) wound on the first sine curve portion within the interval is located on the F wiring layer. The first conductor segment 511 and the second conductor segment 512 are located on the F wiring layer. The corresponding positions (i.e., the peaks of the first sine curve) are connected via vias, and the second conductor segment 512 and the third conductor segment 513 are... The corresponding position (i.e., the trough of the first sine curve) is connected via a via. The first induction coil 51 of the roughing machine... The fifth conductor segment 515 (a total of Q segments) wound on the second sine curve portion within the interval is located on the F wiring layer, along the edge of the first induction coil 51 of the roughing machine. The fourth conductor segment 514 (a total of Q segments) wound around the second sine curve section within the interval and along... The sixth conductor segment 516 (out of a total of Q segments) wound on the second sine curve portion within the interval is located on the E wiring layer. The fourth conductor segment 514 and the fifth conductor segment 515 are located on... The corresponding positions (i.e., the troughs of the second sine curve) are connected via vias, and the fifth conductor segment 515 and the sixth conductor segment 516 are... The corresponding positions (i.e., the peaks of the second sine curve) are connected via vias. The starting ends of the first first conductor segment 511 and the first fourth conductor segment 514 along the positive X direction are connected via vias. The ending ends of the Qth third conductor segment 513 and the Qth sixth conductor segment 516 serve as the output ports of the first induction coil 51 of the roughing machine. Here, j1 takes all integers from 0 to Q-1, Q≥2, and the E wiring layer and F wiring layer are adjacent and both are under the moving scale substrate 2. As an example, Q=2.

[0059] Since the structure of the second induction coil 52 of the roughing machine is the same as that of the first induction coil 51 of the roughing machine, except that the starting ends are staggered along the X direction during arrangement. Therefore, the second induction coil 52 of the roughing machine also has a first wire segment, a second wire segment, a third wire segment, a fourth wire segment, a fifth wire segment, and a sixth wire segment.

[0060] like Figure 6 As shown, the precision induction unit 6 includes components with identical structures, mutually insulated from each other, and whose starting ends are offset along the X direction. The precision machining first induction coil 61 and the precision machining second induction coil 62. The starting end of the precision machining first induction coil 61 is aligned with the starting end of the roughing machining first induction coil 51 along the Y direction.

[0061] The winding trajectory of the first induction coil 61 of the precision machinery is a third sine curve and a fourth sine curve with the same starting position, amplitude A, period W2, number of periods P, and phase difference of 180°. The eighth conductor segment 612 (out of a total of P segments) wound on the third sine curve portion within the interval is located on the E wiring layer, along the edge of the first induction coil 61 of the precision machine. The seventh conductor segment 611 (there are a total of P segments) wound around the third sine curve section within the interval and along... The ninth conductor segment 613 (out of a total of P segments) wound on the third sine curve portion within the interval is located on the F wiring layer. The seventh conductor segment 611 and the eighth conductor segment 612 are located on the F wiring layer. The corresponding positions (i.e., the peaks of the third sine curve) are connected via vias, and the eighth conductor segment 612 and the ninth conductor segment 613 are... The corresponding position (i.e., the trough of the third sine curve) is connected via a via. The first induction coil 61 of the precision machine... The eleventh conductor segment 615 (out of a total of P segments) wound on the fourth sine curve portion within the interval is located on the F wiring layer, along the edge of the first induction coil 61 of the precision machine. The tenth conductor segment 614 (out of a total of P segments) wound on the fourth sine curve section within the interval and along... The twelfth wire segment 616 (a total of P segments) of the fourth sinusoidal curve portion within the interval is located on the E wiring layer, and the tenth wire segment 614 and the eleventh wire segment 615 are connected at the corresponding position (i.e., the trough of the fourth sinusoidal curve) through a via The eleventh wire segment 615 and the twelfth wire segment 616 are connected at the corresponding position (i.e., the peak of the fourth sinusoidal curve) through a via The starting end of the first seventh wire segment 611 and the starting end of the first tenth wire segment 614 are connected through a via along the X positive direction, and the ending end of the Pth ninth wire segment 613 and the ending end of the Pth twelfth wire segment 616 are connected through a via as the sensing signal output port of the first precision machine inductive coil 61; wherein j2 takes all integers from 0 to P-1 in turn, and P≥2. In some embodiments, Roundup() represents rounding up. As an example, P=6.

[0062] Since the structure of the second precision machine inductive coil 62 is the same as that of the first precision machine inductive coil 61, only the starting end is staggered in the X direction when arranged Therefore, the second precision machine inductive coil 62 also has a seventh wire segment, an eighth wire segment, a ninth wire segment, a tenth wire segment, an eleventh wire segment, and a twelfth wire segment.

[0063] The length of the innermost turn of the positive winding planar rectangular spiral coil 71 and the length of the innermost turn of the negative winding planar rectangular spiral coil 72 in the X direction are both L3, and the width in the Y direction is both L4, and L3>max(Q*W1, P*W2), L4>2A, max() represents the maximum value function.

[0064] In some embodiments, the positive winding planar rectangular spiral coil 71 is wound counterclockwise from outside to inside, the negative winding planar rectangular spiral coil 72 is wound clockwise from inside to outside, the starting end of the positive winding planar rectangular spiral coil 71 is connected to the ending end of the negative winding planar rectangular spiral coil 72, and the ending end of the positive winding planar rectangular spiral coil 71 and the starting end of the negative winding planar rectangular spiral coil 72 are connected as the excitation signal input port.

[0065] In some embodiments, the positive winding planar rectangular spiral coil 71 is wound clockwise from inside to outside, the negative winding planar rectangular spiral coil 72 is wound counterclockwise from outside to inside, the starting end of the positive winding planar rectangular spiral coil 71 is connected to the ending end of the negative winding planar rectangular spiral coil 72, and the ending end of the positive winding planar rectangular spiral coil 71 and the starting end of the negative winding planar rectangular spiral coil 72 are connected as the excitation signal input port.

[0066] As Figure 7As shown, in operation, the sensor is reset, the current position of the starting end of the fine machine sensing unit corresponds to the code K = 1 (i.e. the initial value of K is 1), the moving scale moves relative to the fixed scale group, the cosine excitation signal i c = A1cos(ω1t) is input into the excitation unit, the excitation unit generates an alternating air gap magnetic field, the alternating air gap magnetic field periodically changes in the X direction, the coarse machine coupling unit 3 and the fine machine coupling unit 4 generate an alternating magnetic field (the direction of the alternating magnetic field is opposite to that of the alternating air gap magnetic field generated by the excitation unit) under the action of the alternating air gap magnetic field generated by the excitation unit. The coarse machine first sensing coil 51 is coupled with the alternating magnetic field to output the coarse machine sensing signal V1; the coarse machine second sensing coil 52 is coupled with the alternating magnetic field to output the coarse machine sensing signal V2; the fine machine first sensing coil 61 is coupled with the alternating magnetic field to output the fine machine sensing signal V3; and the fine machine second sensing coil 62 is coupled with the alternating magnetic field to output the fine machine sensing signal V4. Wherein, A1 is the amplitude of the cosine excitation signal, ω1 is the angular frequency of the cosine excitation signal, ω1 = 2πf1, f1 represents the frequency of the cosine excitation signal. As an example, f1 = 4MHz.

[0067] The coarse machine sensing signal V1, the coarse machine sensing signal V2, the fine machine sensing signal V3 and the fine machine sensing signal V4 are processed to obtain the absolute linear displacement value x abs of the moving scale relative to the fixed scale group. Specifically, it includes:

[0068] Firstly, the code of the displacement between the starting position of the fine machine coupling unit on the i-th fixed scale and the starting position of the fine machine coupling unit on the i+1-th fixed scale is set as i, i takes all integers from 1 to S-1 in turn, and the code of the displacement between the starting position and the ending position of the fine machine coupling unit on the S-th fixed scale is set as S.

[0069] Secondly, the coarse machine sensing signal V1 is filtered by a first band-pass filter and amplified by a first amplification circuit to obtain a first standing wave signal The coarse machine sensing signal V2 is filtered by a second band-pass filter and amplified by a second amplification circuit to obtain a second standing wave signal The fine machine sensing signal V3 is filtered by a third band-pass filter and amplified by a third amplification circuit to obtain a third standing wave signal The fine machine sensing signal V4 is filtered by a fourth band-pass filter and amplified by a fourth amplification circuit to obtain a fourth standing wave signal Wherein, K1 is the amplitude of the coarse machine sensing signal output by the coarse machine sensing unit 5, and K2 is the amplitude of the fine machine sensing signal output by the fine machine sensing unit 6.

[0070] Thirdly, the first standing wave signal E1 is multiplied by a modulation signal I1 = cos(ω1t), and then the product is filtered by a first low-pass filter and amplified by a fifth amplification circuit to obtain a first electric signal The second standing wave signal E2 is multiplied by the modulation signal I1=cos(ω1t), and then the product is filtered by a second low-pass filter, amplified by a sixth amplification circuit, and a second electric signal is obtained The third standing wave signal E3 is multiplied by the modulation signal I1=cos(ω1t), and then the product is filtered by a third low-pass filter, amplified by a seventh amplification circuit, and a third electric signal is obtained The fourth standing wave signal E4 is multiplied by the modulation signal I1=cos(ω1t), and then the product is filtered by a fourth low-pass filter, amplified by an eighth amplification circuit, and a fourth electric signal is obtained

[0071] In the fourth step, the second electric signal U2 is divided by the first electric signal U1, and the arctangent of the division result is obtained to obtain the phase difference The fourth electric signal U4 is divided by the third electric signal U3, and the arctangent of the division result is obtained to obtain the phase difference The phase difference is converted to obtain the coarse machine incremental displacement Δx' t The phase difference is converted to obtain the fine machine incremental displacement Δx t .

[0072] In the fifth step, the coarse machine incremental displacement Δx' t and the fine machine incremental displacement Δx t are used for polar positioning to obtain the number of polar pairs V of the fine machine excitation unit 4 through which the moving scale passes on the current fixed scale. The current coarse machine incremental displacement Δx' t and the current fine machine incremental displacement Δx t are used to calculate the code K corresponding to the position of the starting end of the current fine machine sensing unit; wherein, 1≤K≤S.

[0073] Wherein, the code K corresponding to the position of the starting end of the current fine machine sensing unit is calculated in the following way:

[0074] If the current displacement difference Δx" t is in the interval [-6, +6], and the last displacement difference Δx" t-1 is in the interval [-6+G N , 6+G N ], then the code K corresponding to the position of the starting end of the current fine machine sensing unit is incremented by 1 (i.e. K=K+1). If the current displacement difference Δx" t is in the interval [-6+G N , 6+G N ], and the last displacement difference Δx" t-1If Δx' ≥ Δx - 6, then the code K corresponding to the position of the starting end of the fine machine inductive unit in the interval [-6, +6] is decremented by 1 (i.e. K = K - 1). The initial value of K is equal to 1; when Δx' t ≥ Δx t - 6, Δx" t = Δx' t - Δx t ; when Δx' t < Δx t - 6, Δx" t = W1 + Δx' t - Δx t ; when Δx' t-1 ≥ Δx t-1 - 6, Δx" t-1 = Δx' t-1 - Δx t-1 ; when Δx' t-1 < Δx t-1 - 6, Δx" t-1 = W1 + Δx' t-1 - Δx t - 1; Δx' t-1 represents the last coarse machine incremental displacement, Δx t-1 represents the last fine machine incremental displacement, 6 represents the preset error limit, G N represents the distance between the left end of the outermost turn of the Mth coarse machine coupling coil 31 and the left end of the outermost turn of the Nth fine machine coupling coil 41 in the X direction. 6, G N are known parameters.

[0075] In the sixth step, the absolute linear displacement value x abs of the moving scale relative to the fixed scale group is calculated by using the formula: x t = (K - 1) * N * W2 + V * W2 + Δx abs .

Claims

1. A spliced ​​absolute time-grid linear displacement sensor, comprising a fixed scale and a movable scale parallel to and opposite the fixed scale with a gap, wherein the fixed scale comprises a fixed scale base (1), the movable scale comprises a movable scale base (2) and a sensing unit disposed on the movable scale base, with the X-direction as the measurement direction, the Y-direction being parallel to the fixed scale base and perpendicular to the X-direction, and the Z-direction being perpendicular to the fixed scale base; characterized in that: The fixed-length base (1) is provided with a roughing coupling unit (3) and a precision coupling unit (4); the roughing coupling unit (3) is composed of M independent roughing coupling coils (31) arranged in a row at equal intervals along the X direction, the roughing coupling coils (31) are in a planar square spiral shape and the starting end is connected to the ending end; the precision coupling unit (4) is composed of N independent precision coupling coils (41) arranged in another row at equal intervals along the X direction, the precision coupling coils (41) are in a planar square spiral shape and the starting end is connected to the ending end; the starting position of the precision coupling unit (4) is aligned with the starting position of the roughing coupling unit (3) in the Y direction; wherein, W1 represents the pole pitch of the coarse-machined coupling unit, W2 represents the pole pitch of the fine-machined coupling unit, M and N are coprime, and M < N. D1 represents the distance in the X direction between the starting position of the precision coupling unit (4) and the left edge of the fixed-length base (1), and D2 represents the distance in the X direction between the ending position of the precision coupling unit (4) and the right edge of the fixed-length base (1). There are S fixed lengths, and the S fixed lengths are spliced ​​together end to end along the X direction to form a fixed length group; The moving scale base (2) is also provided with an excitation unit, which is composed of a forward-wound planar rectangular spiral coil (71) and a reverse-wound planar rectangular spiral coil (72) aligned in the Y direction connected in series; the induction unit includes a roughing machine induction unit (5) located in the reverse-wound planar rectangular spiral coil (72) and facing the roughing machine coupling unit (3) and a precision machine induction unit (6) located in the forward-wound planar rectangular spiral coil (71) and facing the precision machine coupling unit (4). During operation, the sensor is reset, the moving scale moves relative to the fixed scale group, and an excitation signal is passed into the excitation unit to generate an alternating air gap magnetic field. The roughing machine coupling unit (3) and the fine machine coupling unit (4) generate an alternating magnetic field under the action of the alternating air gap magnetic field. The roughing machine sensing unit is coupled with the alternating magnetic field and outputs the roughing machine sensing signal. The fine machine sensing unit is coupled with the alternating magnetic field and outputs the fine machine sensing signal. The roughing machine sensing signal and the fine machine sensing signal are processed to calculate the absolute linear displacement value of the moving scale relative to the fixed scale.

2. The spliced ​​absolute time-grid linear displacement sensor according to claim 1, characterized in that: The coarse machining induction unit (5) comprises units with identical structures, mutually insulated from each other, and whose starting ends are offset along the X direction. The roughing machine first induction coil (51) and roughing machine second induction coil (52); the finishing machine induction unit (6) includes a first induction coil (51) and a second induction coil (52) of the same structure, which are insulated from each other and whose starting ends are offset along the X direction. The first induction coil (61) and the second induction coil (62) of the precision machine, the first induction coil (51) of the roughing machine, the second induction coil (52) of the roughing machine, the first induction coil (61) of the precision machine, and the second induction coil (62) of the precision machine are all formed by connecting wire segments arranged in adjacent layers through vias.

3. The spliced ​​absolute time-grid linear displacement sensor according to claim 2, characterized in that: The winding trajectory of the first induction coil (51) of the roughing machine is a first sine curve and a second sine curve with the same starting position, amplitude A, period W1, number of periods Q, and phase difference of 180°; the winding trajectory of the first induction coil (51) of the roughing machine is... The second conductor segment (512) wound on the first sine curve portion within the interval is located on the E wiring layer, along the first induction coil (51) of the rough machine. The first conductor segment (511) wound around the first sine curve portion within the interval and along The third conductor segment (513) wound on the first sine curve portion within the interval is located on the F wiring layer; the first induction coil (51) of the rough machine along The fifth conductor segment (515) wound on the second sine curve portion within the interval is located on the F wiring layer, along the first induction coil (51) of the coarse machine. The fourth conductor segment (514) wound around the second sine curve portion within the interval and along... The sixth conductor segment (516) wound in the second sine curve section within the interval is located on the E wiring layer. The starting end of the first conductor segment (511) and the starting end of the first fourth conductor segment (514) are connected through a via. The terminating end of the Qth third conductor segment (513) and the terminating end of the Qth sixth conductor segment (516) serve as the induction signal output port of the first induction coil (51) of the coarse machine. Here, j1 takes all integers from 0 to Q-1 in sequence, Q≥2, and the E wiring layer is adjacent to the F wiring layer. The winding trajectory of the first induction coil (61) of the precision machine is a third sine curve and a fourth sine curve with the same starting position, amplitude A, period W2, number of periods P, and phase difference of 180°; the winding trajectory of the first induction coil (61) of the precision machine is a third sine curve and a fourth sine curve with the same starting position, amplitude A, period W2, number of periods P, and phase difference of 180°. The eighth conductor segment (612) wound on the third sine curve portion within the interval is located on the E wiring layer, along the edge of the first induction coil (61) of the precision machine. The seventh conductor segment (611) wound along the third sine curve section within the interval and along The ninth conductor segment (613) wound on the third sine curve portion within the interval is located on the F wiring layer; the first induction coil (61) of the precision machine along The eleventh conductor segment (615) wound on the fourth sine curve portion within the interval is located on the F wiring layer, along the edge of the first induction coil (61) of the precision machine. The tenth conductor segment (614) wound along the fourth sine curve section within the interval and along The twelfth conductor segment (616) wound in the fourth sine curve section within the interval is located on the E wiring layer. The starting end of the first seventh conductor segment (611) and the starting end of the first tenth conductor segment (614) are connected through a via. The terminating end of the Pth ninth conductor segment (613) and the terminating end of the Pth twelfth conductor segment (616) serve as the induction signal output port of the first induction coil (61) of the precision machine. Here, j2 takes all integers from 0 to P-1 in sequence, and P≥2.

4. The spliced ​​absolute time-grid linear displacement sensor according to claim 3, characterized in that: The P, Q, M, and N satisfy: , This represents the function for rounding up.

5. The spliced ​​absolute time-grid linear displacement sensor according to claim 3, characterized in that: The length of the outermost turn of the coarse coupling coil (31) in the X direction is equal to The width in the Y direction is L1, and 2A≤L1<L4; The length of the outermost turn of the precision coupling coil (41) in the X direction is equal to The width in the Y direction is L2, and 2A≤L2<L4; The innermost turn of both the forward-wound planar rectangular helical coil (71) and the reverse-wound planar rectangular helical coil (72) has a length of L3 in the X direction and a width of L4 in the Y direction. , , This represents the function that takes the maximum value.

6. The spliced ​​absolute time-grid linear displacement sensor according to any one of claims 3 to 5, characterized in that: The coarse machine coupling coil (31) is wound counterclockwise from the inside to the outside into a planar square spiral shape, and the fine machine coupling coil (41) is wound counterclockwise from the inside to the outside into a planar square spiral shape; Alternatively, the coarse machine coupling coil (31) can be wound clockwise from the outside to the inside into a planar square spiral shape, and the fine machine coupling coil (41) can be wound clockwise from the outside to the inside into a planar square spiral shape.

7. The spliced ​​absolute time-grid linear displacement sensor according to any one of claims 3 to 5, characterized in that: The forward-wound planar rectangular spiral coil (71) is wound counterclockwise from the outside to the inside, and the reverse-wound planar rectangular spiral coil (72) is wound clockwise from the inside to the outside. The starting end of the forward-wound planar rectangular spiral coil (71) is connected to the ending end of the reverse-wound planar rectangular spiral coil (72). The lead wires of the ending end of the forward-wound planar rectangular spiral coil (71) and the starting end of the reverse-wound planar rectangular spiral coil (72) serve as excitation signal input ports. Alternatively, the forward-wound planar rectangular spiral coil (71) is wound clockwise from the inside to the outside, and the reverse-wound planar rectangular spiral coil (72) is wound counterclockwise from the outside to the inside. The terminating end of the forward-wound planar rectangular spiral coil (71) is connected to the starting end of the reverse-wound planar rectangular spiral coil (72), and the leads of the starting end of the forward-wound planar rectangular spiral coil (71) and the terminating end of the reverse-wound planar rectangular spiral coil (72) serve as excitation signal input ports.

8. The spliced ​​absolute time-grid linear displacement sensor according to any one of claims 2 to 5, characterized in that, The methods for processing the roughing and finishing machine induction signals to calculate the absolute linear displacement value of the moving scale relative to the fixed scale include: The displacement between the starting position of the precision coupling unit on the i-th fixed length and the starting position of the precision coupling unit on the i+1 fixed length is encoded as i, where i takes all integers from 1 to S-1 in sequence. The displacement between the starting position and the ending position of the precision coupling unit on the S-th fixed length is encoded as S. The phase difference is obtained by processing the coarse machining induction signal. The phase difference is obtained by processing the precision machine's sensing signal. ; phase difference The current incremental displacement of the roughing machine is obtained by conversion. Regarding phase difference The current incremental displacement of the precision machine is obtained by conversion. ; Utilizing the current roughing machine incremental displacement Current precision machine incremental displacement Perform pole alignment to obtain the pole number V of the precision coupling unit (4) that the moving scale passes through on the current fixed scale; Utilizing the current roughing machine incremental displacement Current precision machine incremental displacement Calculate the code K corresponding to the starting position of the precision sensing unit, where 1≤K≤S; Using the formula: The absolute linear displacement value x of the moving scale relative to the fixed scale group was calculated. abs .

9. The spliced ​​absolute time-grid linear displacement sensor according to claim 8, characterized in that, Utilizing the current roughing machine incremental displacement Current precision machine incremental displacement The method for calculating the code K corresponding to the current starting position of the precision machine sensing unit is as follows: If the current displacement difference In the interval Inside, and the previous displacement difference In the interval If the code K is incremented by 1, then the encoding K is incremented by 1. If the current displacement difference In the interval Inside, and the previous displacement difference In the interval If the code K is incremented by 1, then the encoding K is decremented by 1. Where, the initial value of K is equal to 1; when ≥ hour ;when hour, ;when ≥ hour ;when hour, ; This indicates the previous roughing mill increment displacement. This indicates the previous precision machine increment displacement. G represents the preset error limit. N This represents the distance in the X direction between the left end of the outermost turn of the Mth coarse coupling coil (31) and the left end of the outermost turn of the Nth fine coupling coil (41).

10. The spliced ​​absolute time-grid linear displacement sensor according to claim 9, characterized in that: The phase difference is obtained by processing the coarse machining induction signal. The method is as follows: The roughing machine induction signal V1 output by the first induction coil (51) of the roughing machine is filtered by the first bandpass filter and amplified by the first amplifier circuit to obtain the first standing wave signal E1; the roughing machine induction signal V2 output by the second induction coil (52) of the roughing machine is filtered by the second bandpass filter and amplified by the second amplifier circuit to obtain the second standing wave signal E2. The first standing wave signal E1 is multiplied by the modulation signal I1, then filtered by the first low-pass filter and amplified by the fifth amplifier circuit to obtain the first electrical signal U1; the second standing wave signal E2 is multiplied by the modulation signal I1, then filtered by the second low-pass filter and amplified by the sixth amplifier circuit to obtain the second electrical signal U2. Divide the second electrical signal U2 by the first electrical signal U1, and calculate the arctangent of the division result to obtain the phase difference. ; The phase difference is obtained by processing the precision machine induction signal. The method is as follows: The precision machine induction signal V3 output by the first precision machine induction coil (61) is filtered by the third bandpass filter and amplified by the third amplifier circuit to obtain the third standing wave signal E3; the precision machine induction signal V4 output by the second precision machine induction coil (62) is filtered by the fourth bandpass filter and amplified by the fourth amplifier circuit to obtain the fourth standing wave signal E4. The third standing wave signal E3 is multiplied by the modulation signal I1, then filtered by the third low-pass filter and amplified by the seventh amplifier circuit to obtain the third electrical signal U3; the fourth standing wave signal E4 is multiplied by the modulation signal I1, then filtered by the fourth low-pass filter and amplified by the eighth amplifier circuit to obtain the fourth electrical signal U4. Divide the fourth electrical signal U4 by the third electrical signal U3, and calculate the arctangent of the division result to obtain the phase difference. .

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