CN117723093A - Magnetic encoder with anti-interference function - Google Patents

Abstract

The invention relates to the technical field of encoders, in particular to a magnetic encoder with anti-interference function. The device comprises a magnetic field generator, a first magnetic field generator and a second magnetic field generator, wherein the magnetic field generator generates an object magnetic field containing magnetic field components in a first direction, a second direction and a third direction, and the object magnetic field is a non-fixed periodic magnetic field, and the first direction, the second direction and the third direction are mutually perpendicular; a magnetic sensor configured to detect the object magnetic field in one of a first direction, a second direction, and a third direction; the magnetic sensor is configured to comprise a first magnetic induction unit and a second magnetic induction unit, and the first potential and the second potential corresponding to the magnetic field component intensity are generated respectively, so that in specific working conditions, the anti-jamming capability of the PRBS code channel decoding method is higher than that of the prior art, and decoding can be performed on the PRBS code channel more accurately, so that the position judgment of a subsequent central processing unit is difficult to make mistakes.

Description

Magnetic encoder with anti-interference function

Technical Field

The invention relates to the technical field of encoders, in particular to a magnetic encoder with anti-interference function.

Background

Encoders are measuring devices for determining the position of two bodies (such as a magnetic field generator and a magnetic sensor) that are relatively movable with respect to a linear direction or a rotational direction, and are currently widely used as displacement or angle measuring devices in the fields of civil instruments, industrial control, and the like. Encoders can be classified into incremental encoders and absolute encoders according to functions, and optical encoders, magnetic encoders, and the like according to sensor types.

As shown in fig. 1a, in the prior art, an incremental track (magnetic field generator) of a general magnetic encoder is formed by alternately arranging N magnetic poles (hereinafter abbreviated as N poles) and S magnetic poles (hereinafter abbreviated as S poles) with a fixed pole pitch p (the distance between the centers of the N poles and the S poles is p, and the width of the N poles and the S poles in the relative movement direction is also p), and the period of an amplitude curve of a component of a magnetic field generated by the incremental track is 2p; as shown in fig. 1, the magnetic sensor includes an a-phase bridge circuit (left half of fig. 1B) and a B-phase bridge circuit (right half of fig. 1B) each including MR elements, and the plurality of MR elements are arranged at intervals of p/2 distances in the direction of relative movement (i.e., the R1, R2, R3, and R4 are sequentially spaced at intervals of p/2 distances in the direction of relative movement), so that output waveforms of an amount of phase shift of p/2 (90 °) can be obtained from the a-phase bridge circuit and the B-phase bridge circuit, and the position detection can be realized after processing calculation of the output VA of the a-phase bridge circuit and the output VB of the B-phase bridge circuit.

Absolute encoders typically output absolute position. In an absolute encoder design employing PRBS (pseudo-random binary sequence) code tracks, the N-poles and S-poles of the PRBS code tracks are not alternately arranged, and the arrangement of the N-poles and S-poles is arranged according to a pseudo-random binary sequence, as shown in FIGS. 2 and 3. The amplitude profile of the component of the magnetic field generated by the PRBS code track in either direction is not a fixed periodic waveform and the arrangement of the sensor in fig. 1a is not suitable for the PRBS code track, which cannot be decoded efficiently.

The magnetic encoder may be affected by an external interference magnetic field in the use process, and the interference magnetic field may cause that the magnetic field sensed by the magnetic sensor is not a magnetic field generated by a real code channel, so that the magnetic field acquired by the magnetic sensor has larger deviation, for example, in the process of position detection, the problem of position error or position unaddressed easily occurs; for the PRBS code, it cannot decode the PRBS code more accurately.

Disclosure of Invention

Accordingly, the present invention is directed to overcoming the above-mentioned problems occurring in the prior art, and thus providing a magnetic encoder with anti-interference capability, which can realize the decoding of PRBS tracks in an absolute encoder in the presence of external magnetic field interference, and obtain a relatively accurate coded signal of PRBS.

The invention provides a magnetic encoder with anti-interference function, which comprises:

a magnetic field generator generating an object magnetic field including magnetic field components in a first direction, a second direction, and a third direction, the object magnetic field being a non-fixed periodic magnetic field, wherein the first direction, the second direction, and the third direction are perpendicular to each other;

a magnetic sensor configured to detect the object magnetic field in one of a first direction, a second direction, and a third direction;

the magnetic sensor is configured to include a first magnetic induction unit and a second magnetic induction unit, and generate a first potential and a second potential corresponding to the magnetic field component intensity, respectively;

the first magnetic induction unit and the second magnetic induction unit are configured in one of the first direction, the second direction or the third direction in a manner that the difference value between the first potential and the second potential is related to the intensity of the magnetic field component.

Further, the magnetic field generator is a double code channel which is arranged in parallel, and the magnetic field generator is composed of a plurality of groups of N poles and S poles, wherein one of the first direction, the second direction or the third direction is the extending direction of the code channel.

Further, the double code channels are PRBS code channels with N poles and S poles arranged according to pseudo-random binary sequences.

Further, the first magnetic induction unit and the second magnetic induction unit are respectively arranged at a first position and a second position, and a connecting line of the first position and the second position is parallel to the direction.

Further, the first position is a middle position of one of the double code channels, and the second position is a middle position of the other one of the double code channels.

Further, the first position is the middle position of one of the two code channels, and the second position is the middle position of the other of the two code channels.

Further, the magnetic sensitivity directions of the first magnetic induction unit and the second magnetic induction unit are the same and are parallel to the direction of the detected magnetic field component.

Further, the first magnetic induction unit comprises a first magnetic induction element and a fourth magnetic induction element, and the second magnetic induction unit comprises a second magnetic induction element and a third magnetic induction element;

the first potential is a voltage value between the first magnetic induction element and the second magnetic induction element, and the second potential is a voltage value between the third magnetic induction element and the fourth magnetic induction element.

Further, the first magnetic induction unit comprises a fifth magnetic induction element, and the second magnetic induction unit comprises a sixth magnetic induction element;

the first potential is a voltage value between the fifth magnetic induction element and the sixth magnetic induction element, and the second potential is a reference voltage.

The technical scheme of the invention has the following advantages:

the invention provides a magnetic encoder with anti-interference function, wherein a first magnetic induction unit comprises a first magnetic induction element and a fourth magnetic induction element, and a second magnetic induction unit comprises a second magnetic induction element and a third magnetic induction element; the first potential is a voltage value between the first magnetic induction element and the second magnetic induction element, and the second potential is a voltage value between the third magnetic induction element and the fourth magnetic induction element. The first magnetic induction unit comprises a fifth magnetic induction element, and the second magnetic induction unit comprises a sixth magnetic induction element; the first potential is a voltage value between the fifth magnetic induction element and the sixth magnetic induction element, and the second potential is a reference voltage. Can make in the concrete operating mode, the interference ratio of this application is less than prior art's interference ratio, and this application interference killing feature is greater than prior art's interference killing feature promptly, therefore this application can be more accurate decodes PRBS code channel for follow-up central processing unit is in carrying out the position judgement and is difficult for makeing mistakes.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are needed in the description of the embodiments or the prior art will be briefly described, and it is obvious that the drawings in the description below are some embodiments of the present invention, and other drawings can be obtained according to the drawings without inventive effort for a person skilled in the art.

FIG. 1a is a schematic diagram of an incremental track and a magnetoresistive distribution in the prior art;

FIG. 1b is a schematic diagram of a circuit structure composed of a prior art magnetoresistive element;

FIG. 1c is a schematic diagram of a prior art output waveform;

FIG. 2 is a schematic diagram of a linear magnetic field generator according to the present invention;

FIG. 3 is a schematic diagram of a magnetic disk type magnetic field generator according to the present invention

FIG. 4 is a schematic diagram of a comparison of a magnetic field with and without interference;

FIG. 5 is a schematic diagram of an arrangement of magnetic sensor magnetic induction elements of the present invention with magnetic field components at different locations in a first direction;

FIG. 6 is a circuit diagram of a magnetic sensor of the present invention composed of four magnetic induction elements;

FIG. 7 is a schematic diagram of a differential operation circuit according to the present invention;

FIG. 8 is a comparative schematic diagram of the anti-jamming capability of the present invention and the prior art;

FIG. 9 is a schematic diagram of the magnetic sensor magnetic induction element arrangement of the present invention in a half-bridge configuration with magnetic field components at different locations in a first direction;

FIG. 10 is a circuit diagram of two magnetic induction elements of a magnetic sensor in a half-bridge configuration according to the present invention;

FIG. 11 is a schematic diagram of a magnetic sensor magnetic induction element arrangement in a full bridge configuration and a side view of magnetic field components at different locations in a first direction in accordance with the present invention;

FIG. 12 is a graph showing a magnetic field distribution of a dual code channel according to the present invention;

FIG. 13 shows magnetic field components in three directions at a first position and a second position of a dual track according to the present invention.

Reference numerals illustrate;

1. a magnetic field generator; 2. a magnetic sensor; 3. a first magnetic induction element; 4. a second magnetic induction element; 5. a third magnetic induction element; 6. and a fourth magnetic induction element.

Detailed Description

The following description of the embodiments of the present invention will be made apparent and fully in view of the accompanying drawings, in which some, but not all embodiments of the invention are shown. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

In the description of the present invention, it should be noted that the directions or positional relationships indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. are based on the directions or positional relationships shown in the drawings, are merely for convenience of describing the present invention and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the present invention, it should be noted that, unless explicitly specified and limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be either fixedly connected, detachably connected, or integrally connected, for example; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the above terms in the present invention will be understood in specific cases by those of ordinary skill in the art.

In addition, the technical features of the different embodiments of the present invention described below may be combined with each other as long as they do not collide with each other.

Examples

Magnetic encoders can be classified into absolute encoders and incremental encoders, and the present application is mainly directed to absolute encoders, but can also be applied to incremental encoders. The present application is primarily described in terms of an absolute encoder employing PRBS tracks. The PRBS code channel has the greatest advantage that decoding at a static position can be realized, and absolute position or absolute angle information can be obtained.

Fig. 1a, 1b and 1c are diagrams of incremental encoders in the background art.

A magnetic encoder embodiment with tamper resistance as shown in fig. 2 to 13, the magnetic encoder with tamper resistance comprising: a magnetic field generator 1 that generates an object magnetic field including magnetic field components in a first direction, a second direction, and a third direction, the object magnetic field being a non-fixed periodic magnetic field, wherein the first direction, the second direction, and the third direction are perpendicular to each other; a magnetic sensor 2 configured to detect the object magnetic field in one of a first direction, a second direction, and a third direction; if the magnetic field generator 1 is linear, as shown in fig. 2, the X direction, the Y direction and the Z direction are defined, in this embodiment, the extending direction of the magnetic field generator 1 is defined as the X direction, the direction perpendicular to the X direction in the horizontal plane is defined as the Y direction, and the direction perpendicular to the XY component plane is defined as the Z direction, but the present embodiment is not limited thereto. In this embodiment, the Z direction is set as the first direction, the Y direction is set as the second direction, and the X direction is set as the third direction. If the magnetic field generator 1 is a magnetic ring or a magnetic disk, as shown in fig. 3, the circumferential direction is defined as the X direction, the radial direction is defined as the Y direction, the direction perpendicular to the XY component plane is defined as the Z direction, and similarly, the Z direction is defined as the first direction, the Y direction is defined as the second direction, and the X direction is defined as the third direction.

As shown in fig. 4, the code track is a section of the PRBS code track, the binary code corresponding to the N pole is set to "1", the binary code corresponding to the S pole is set to "0", when the magnetic encoder works and the interference field has a component in the first direction, the magnetic field component in the first direction sensed by the magnetic sensor 2 has larger deviation, so that the comparison window fails or is partially failed, thus the obtained binary output has a problem of distortion, resulting in decoding error of the PRBS code track, and thus, the problem that the position error/position cannot be found when the subsequent central processing unit performs position judgment. Of course, it is also possible to set the binary code corresponding to the S pole to "1" and the binary code corresponding to the N pole to "0".

The disturbing magnetic field can be regarded as a constant quantity. The present application is directed to reading the gradient of the magnetic field at the location where the distance difference in the first direction is (d 2-d 1), as shown in fig. 5 and 11, which is basically true feedback and detection coding with respect to the coding of the PRBS tracks, but the gradient magnetic field of this distance difference is small and negligible with respect to the external disturbing magnetic field.

In addition, the magnetic field signal of the PRBS code channel is a magnetic field close to the magnetic sensor, the external interference magnetic field is a magnetic field far away from the magnetic sensor, and the square attenuation relation of the magnetic field can be intuitively obtained, so that the capability of resisting the external magnetic field of the gradient design is strong.

The magnetic sensor 2 includes a first magnetic induction unit and a second magnetic induction unit, which may be composed of magnetic induction elements that may be magneto-resistors or hall elements, and generate a first electric potential and a second electric potential corresponding to the intensity of the magnetic field component, respectively; and obtaining the codes of the positions on the PRBS code channels corresponding to the positions of the current magnetic sensor 2 by carrying out subsequent processing on the outputs of the first potential and the second potential, thereby realizing decoding.

The first magnetic induction unit and the second magnetic induction unit are configured in one of the first direction, the second direction or the third direction in a manner that the difference value between the first potential and the second potential is related to the intensity of the magnetic field component. If the first magnetic induction unit and the second magnetic induction unit are disposed along the first direction, it may be considered that the connecting line between the positions of the first magnetic induction unit and the second magnetic induction unit is parallel to the first direction. The first magnetic induction unit and the second magnetic induction unit are arranged along the second direction, and the connecting lines of the positions of the first magnetic induction unit and the second magnetic induction unit are considered to be parallel to the second direction in the same way. The first magnetic induction unit and the second magnetic induction unit are arranged along the third direction, and the connecting lines of the positions of the first magnetic induction unit and the second magnetic induction unit are considered to be parallel to the third direction in the same way. And under different magnetic field component intensities, the difference between the first potential and the second potential is different, and the PRBS code channel is decoded after processing operation is performed on the difference.

The magnetic field generator 1 is a double code channel which is arranged in parallel, the magnetic field generator 1 is composed of a plurality of groups of N poles and S poles, one of the first direction, the second direction or the third direction is the extending direction of the code channel, and the double code channel is a PRBS code channel in which the N poles and the S poles are arranged according to a pseudo-random binary sequence. At this time, the PRBS track has magnetic field components in the first direction, the second direction, and the third direction, and has a magnetic field difference in the first position and the second position, as shown in fig. 12 and 13. The code track shown in fig. 2 is a section of PRBS code track, which is not limited to this embodiment. Of course, a plurality of groups of incremental code tracks formed by alternately arranging N poles and S poles are also applicable.

Further, the first magnetic induction unit and the second magnetic induction unit are respectively arranged at a first position and a second position, and a connecting line of the first position and the second position is parallel to the direction. The first location is typically a distance from the bi-channel.

Further, the first position is a middle position of two code channels, and the second position is a middle position of one of the two code channels, as shown in fig. 5 and 11. At this time, the first position and the second position are one of the optimal positions, and more accurate detection can be achieved.

Further, the first position is the middle position of one of the two code channels, and the second position is the middle position of the other of the two code channels. In this case, the first position and the second position are one of the optimal positions, and are particularly used for detecting the magnetic field component in the first direction, so that more accurate detection can be realized.

In this embodiment, the first magnetic induction unit and the second magnetic induction unit are disposed in the second direction (i.e. the Y direction) and detect the magnetic field component in the second direction, as shown in fig. 5 and 11, the first position may be the d1 position in fig. 5, the second position may be the d2 position in fig. 5, and in this embodiment, the first position and the second position may be considered as a position point indicating the position.

Further, the magnetic sensitivity directions of the first magnetic induction unit and the second magnetic induction unit are the same and are parallel to the direction of the detected magnetic field component. If a magnetic field component in a first direction is detected, the magnetic sensitivity directions of the first magnetic induction unit and the second magnetic induction unit are parallel to the first direction. If the magnetic field component in the second direction is detected, the magnetic sensitivity directions of the first magnetic induction unit and the second magnetic induction unit are parallel to the second direction. If the magnetic field component in the third direction is detected, the magnetic sensitivity directions of the first magnetic induction unit and the second magnetic induction unit are parallel to the third direction. In this embodiment, the first magnetic induction unit and the second magnetic induction unit are disposed in the second direction (i.e. Y direction), and the magnetic sensor 2 detects the object magnetic field in the second direction, as shown in fig. 5, so that the magnetic sensitivity direction is parallel to the second direction when the first magnetic induction unit and the second magnetic induction unit are selected. According to the application, whether the object magnetic field in the first direction, the second direction or the third direction is detected is selected according to the requirements, and accordingly, the first magnetic induction unit and the second magnetic induction unit with the magnetic sensitivity direction consistent with the detection direction are selected.

Further, as shown in fig. 5, the first magnetic induction unit includes a first magnetic induction element 3 and a fourth magnetic induction element 6, and the second magnetic induction unit includes a second magnetic induction element 4 and a third magnetic induction element 5; the first potential is a voltage value between the first magnetic induction element 3 and the second magnetic induction element 4, and the second potential is a voltage value between the third magnetic induction element 5 and the fourth magnetic induction element 6. In this case it can be considered a full bridge structure of the present embodiment.

The distance between the first magnetic induction element 3 and the fourth magnetic induction element 6 and the XZ plane is set to be d1, the distance between the second magnetic induction element 4 and the third magnetic induction element 5 and the XZ plane is set to be d2, fig. 5 shows the distribution of the first magnetic induction element 3, the second magnetic induction element 4, the third magnetic induction element 5 and the fourth magnetic induction element 6, and fig. 12 shows the magnetic field component in the X, Y, Z direction at the positions d1 and d2, respectively, wherein the first magnetic induction element 3, the second magnetic induction element 4, the third magnetic induction element 5 and the fourth magnetic induction element 6 may use magneto-resistors or hall elements. It should be noted that if the Y direction is the first direction, or the X direction is the first direction, the derivation process is the same.

It should be noted that, the magnetic sensor 2 further includes a Vcc port, a GND port, a v+ port, and a V-port;

the first magnetic induction element 3 is arranged on a path for connecting a Vcc port and a V-port, the second magnetic induction element 4 is arranged on a path for connecting a V-port and a GND port, the third magnetic induction element 5 is arranged on a path for connecting a Vcc port and a V+ port, and the fourth magnetic induction element 6 is arranged on a path for connecting a V+ port and a GND port;

the potential signal of the V+ port is a first potential, and the potential signal of the V-port is a second potential. Further, as shown in fig. 7, the magnetic sensor 2 further includes a differential operation circuit, a v+ input end of the differential operation circuit is connected with the v+ port, a V-input end of the differential operation circuit is connected with the V-port, and an output of the differential operation circuit is:

typically, ra=rb=rd, vout=v+ -V-.

Let the resistances of the first magnetic induction element 3, the second magnetic induction element 4, the third magnetic induction element 5, and the fourth magnetic induction element 6 be R1, R2, R3, and R4.

In this application, R1, R2, R3, and R4 in the presence of an interfering magnetic field can be expressed as formulas 1, 2, 3, and 4, respectively:

R1＝R+S*(H1+H0)……(1)

R2＝R+S*(H2+H0)……(2)

R3＝R+S*(H2+H0)……(3)

R4＝R+S*(H1+H0)……(4)

wherein R is the resistance of the first magnetic induction element 3, the second magnetic induction element 4, the third magnetic induction element 5 and the fourth magnetic induction element 6 without an externally applied magnetic field, the unit is ohm (Ω), H1 is the second-direction magnetic field component of the object magnetic field at the first magnetic induction element 3 and the fourth magnetic induction element 6, H2 is the second-direction magnetic field component of the object magnetic field at the second magnetic induction element 4 and the third magnetic induction element 5, H0 is the magnetic field component of the disturbing magnetic field in the second direction, the unit is gauss (Gs), S is the sensitivity coefficient of the first to fourth magnetic induction elements, and the unit is Ω/Gs.

Then: v+=vcc R4/(r3+r4)

＝Vcc*(R+S(H1+H0))/(R+S(H2+H0)+R+S(H1+H0))

＝Vcc*(R+S*H1+S*H0)/(2R+S*H2+S*H1+2S*H0)

V-＝Vcc*R2/(R1+R2)

＝Vcc*(R+S*H2+S*H0)/(2R+S*H1+S*H2+2S*H0)

Wherein, H1 is greater than H2, for convenience of calculation, H2 can be regarded as 0, without affecting the subsequent processing result.

The output voltage of the application under the interference magnetic field is as follows:

V1＝V+-V-＝Vcc*S*H1/(2R+S*H1+2S*H0)……(5)

the output voltage under the undisturbed magnetic field (i.e. h0=0) is:

V0＝V+-V-＝Vcc*S*H1/(2R+S*H1)……(6)

it is thus possible to obtain a solution,

interference ratio = V1-V0 i/V0 in the present application

＝2*S*H0/(2*R+S*H1+2*S*H0)……(7)

In decoding the conventional object magnetic field with a non-fixed period, four magnetoresistors are located at the same position, and as a comparison, it can be considered that the four magnetoresistors are located at d1, where the magnetic field component of the object magnetic field is H1, the magnetic sensitivity directions of the first magnetic induction element 3 and the fourth magnetic induction element 6 are identical (along the positive Y-axis direction), the magnetic sensitivity directions of the second magnetic induction element 4 and the third magnetic induction element 5 are identical (along the negative Y-axis direction) and opposite to the sensitivity directions of the first magnetic induction element 3 and the fourth magnetic induction element 6, respectively (if the magnetic sensitivity directions are identical, vout is always 0, meaning that the magnetic sensitivity directions are completely identical), so it can be assumed that the resistance values of R1, R2, R3, and R4 are r1=r4=r+s (h1+h0), r2=r3=r-S (h1+h0), respectively.

In the case of the prior art, it is known,

V′+＝Vcc*R4/(R3+R4)

＝Vcc*(R+S*(H1+H0))/(2*R)

V′-＝Vcc*R2/(R1+R2)

＝Vcc*(R-S*(H1+H0))/(2*R)

therefore, the output voltage under the disturbing magnetic field in the prior art is:

V2＝V′+-V′-＝Vcc*S*(H1+H0)/R……(8)

the output voltage under the undisturbed magnetic field (i.e. h0=0) is:

V′0＝Vcc*S*H1/R……(9)

it is thus possible to obtain a solution,

prior art interference ratio = V2-V '0 i/V' 0

＝H0/H1……(10)

Comparing the magnitudes of equation 7 and equation 10, it can be seen that:

the interference ratio of the present application is smaller than the interference ratio of the prior art when s×h1 < 2r+2s×h0.

In typical applications, R is typically several kiloohms, H1 is typically zero to several hundred Gs, H0 < H1, S is typically several Ω/Gs, specifically, R is 7500 Ω, H1 is 300Gs, S is 8 Ω/Gs, and H0 is valued from 0 to 300 Gs. As shown in fig. 8, the horizontal axis represents interference field to signal field ratio, i.e., H0/H1, and the vertical axis represents interference degree (interference ratio), and the smaller the interference degree (the smaller the interference ratio), the stronger the anti-interference capability is. The prior art design of fig. 8 is specifically a curve corresponding to the assigned formula 10; the present application in fig. 8, specifically, the curve corresponding to the assigned formula 7, can be obviously shown in fig. 8, where the interference degree of the existing design is always greater than that of the present application, that is, the anti-interference capability of the existing design is always less than that of the present application.

In addition, the magnetic sensor 2 may further include a signal processing circuit, which may be implemented by an Application Specific Integrated Circuit (ASIC) or a microcomputer, for obtaining the magnitude of the magnetic field induced by the magnetic sensor 2 based on the first potential output and the second potential output and deriving therefrom the code of the corresponding position on the PRBS code track corresponding to the current position.

It should be noted that in other embodiments, the plurality of magnetic sensors 2 may be arranged at intervals m in sequence along the extending direction of the code channel (m is the width of each coding region, that is, the width of each N pole and each S pole along the extending direction of the code channel), and assuming that N is greater than or equal to 1, each magnetic sensor 2 obtains a potential difference, and after subsequent processing, the codes "0" or "1" at the positions on the PRBS code channel corresponding to the magnetic sensor 2 at the current position are obtained, so that a group of binary codes of N bits are obtained, and accordingly, the specific position is confirmed, and position detection is implemented.

Further, as shown in fig. 9 and 10, the first magnetic induction unit includes a fifth magnetic induction element 7, and the second magnetic induction unit includes a sixth magnetic induction element 8; the first potential is a voltage value between the fifth magnetic induction element 7 and the sixth magnetic induction element 8, the fifth magnetic induction element 7 and the sixth magnetic induction element 8 may be magneto-resistors or hall elements, and the second potential is a reference voltage. In this case it can be considered a half-bridge structure of the present embodiment. The deduction steps are similar to the full-bridge structure, and the deduction steps are not repeated, so that the anti-interference capability of the method is higher than that of the prior art under the half-bridge structure.

It is apparent that the above examples are given by way of illustration only and are not limiting of the embodiments. Other variations or modifications of the above teachings will be apparent to those of ordinary skill in the art. It is not necessary here nor is it exhaustive of all embodiments. While still being apparent from variations or modifications that may be made by those skilled in the art are within the scope of the invention.

Claims (9)

1. A magnetic encoder with tamper resistance, comprising:

a magnetic field generator (1) for generating an object magnetic field containing magnetic field components in a first direction, a second direction and a third direction, wherein the object magnetic field is a non-fixed periodic magnetic field, and the first direction, the second direction and the third direction are mutually perpendicular;

a magnetic sensor (2) configured to detect the object magnetic field in one of a first direction, a second direction, and a third direction;

the magnetic sensor (2) is configured to include a first magnetic induction unit and a second magnetic induction unit, and to generate a first potential and a second potential corresponding to the magnetic field component intensity, respectively;

the first magnetic induction unit and the second magnetic induction unit are configured in one of the first direction, the second direction or the third direction in a manner that the difference value between the first potential and the second potential is related to the intensity of the magnetic field component.

2. The magnetic encoder with interference resistance according to claim 1, wherein the magnetic field generator (1) is a double code track arranged in parallel, the magnetic field generator (1) is composed of a plurality of sets of N poles and S poles, wherein one of the first direction, the second direction or the third direction is an extension direction of the code track.

3. The magnetic encoder with interference resistance of claim 2, wherein the dual tracks are PRBS tracks arranged in a pseudo-random binary sequence for the N-pole and S-pole.

4. The magnetic encoder of claim 1, wherein the first magnetic induction unit and the second magnetic induction unit are disposed at a first position and a second position, respectively, and a connecting line of the first position and the second position is parallel to the direction.

5. The tamper-resistant magnetic encoder of claim 4, wherein the first position is a double track intermediate position and the second position is a double track intermediate position.

6. The tamper-resistant magnetic encoder of claim 4, wherein the first position is a middle position of one of the dual tracks and the second position is a middle position of the other of the dual tracks.

7. The magnetic encoder with interference resistance according to claim 4, wherein the magnetic sensitivity directions of the first magnetic induction unit and the second magnetic induction unit are the same and parallel to the detected magnetic field component direction.

8. The magnetic encoder with immunity to interference according to claim 1, characterized in that the first magnetic induction unit comprises a first magnetic induction element (3) and a fourth magnetic induction element (6), the second magnetic induction unit comprises a second magnetic induction element (4) and a third magnetic induction element (5);

wherein the first potential is a voltage value between the first magnetic induction element (3) and the second magnetic induction element (4), and the second potential is a voltage value between the third magnetic induction element (5) and the fourth magnetic induction element (6).

9. The magnetic encoder with immunity to interference according to claim 1, characterized in that the first magnetic induction unit comprises a fifth magnetic induction element (7) and the second magnetic induction unit comprises a sixth magnetic induction element (8);

wherein the first potential is the voltage value between the fifth magnetic induction element (7) and the sixth magnetic induction element (8), and the second potential is the reference voltage.