CN120232331A - An absolute position detection system - Google Patents
An absolute position detection system Download PDFInfo
- Publication number
- CN120232331A CN120232331A CN202510394928.0A CN202510394928A CN120232331A CN 120232331 A CN120232331 A CN 120232331A CN 202510394928 A CN202510394928 A CN 202510394928A CN 120232331 A CN120232331 A CN 120232331A
- Authority
- CN
- China
- Prior art keywords
- magnetic
- absolute position
- grid
- field sensing
- sensing module
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Landscapes
- Measurement Of Length, Angles, Or The Like Using Electric Or Magnetic Means (AREA)
Abstract
本申请提供一种绝对位置检测系统，包括：以交替排列N‑S磁极形成的磁栅，磁场感测模块以及位置计算模块。在磁极排列方向上，所述磁栅的磁极的高度相同、宽度形成等差数列。磁场感测模块由四个在平行于所述磁栅平面上等间隔排列、感测系数大小相等、感测方向相同的磁阻构成。所述位置计算模块根据所述磁场感测模块正对所述磁栅的不同位置对应的输出信号的唯一性，确定所述磁场感测模块相对于磁栅起始点的位置。本申请提供的绝对位置检测系统配合相应的计算方法，实现以单一磁道实现绝对位置的测量，大大缩小了绝对位置检测系统的尺寸，能够很好的适应狭窄空间范围内的绝度位置检测的应用需求。
The present application provides an absolute position detection system, comprising: a magnetic grid formed by alternatingly arranging N‑S magnetic poles, a magnetic field sensing module and a position calculation module. In the direction of magnetic pole arrangement, the height of the magnetic poles of the magnetic grid is the same and the width forms an arithmetic progression. The magnetic field sensing module is composed of four magnetic resistors that are arranged at equal intervals parallel to the plane of the magnetic grid, have equal sensing coefficients and the same sensing direction. The position calculation module determines the position of the magnetic field sensing module relative to the starting point of the magnetic grid based on the uniqueness of the output signal corresponding to different positions of the magnetic field sensing module facing the magnetic grid. The absolute position detection system provided in the present application cooperates with the corresponding calculation method to realize the measurement of absolute position with a single magnetic track, which greatly reduces the size of the absolute position detection system and can well adapt to the application requirements of absolute position detection within a narrow space.
Description
Technical Field
The application relates to the technical field of position or distance measurement/sensing, in particular to an absolute position detection system based on magnetic field measurement.
Background
Along with the development of modern technology and the improvement of automation level, a large number of displacement sensors which truly and reliably reflect the position information of a measured object are required in the fields of aerospace, mechanical manufacturing, high-precision numerical control machine tools and the like, the displacement sensor system is required to be small in size, light in weight and high in response speed, is insensitive to a measuring environment (such as temperature, dust, light rays and electromagnetic interference) and can timely know the position of a target relative to a reference point at any time point of the starting and working processes of the measuring system.
The position detection system based on the magnetic field is insensitive to the factors such as temperature, dust, light and the like in the measuring environment, and electromagnetic interference can be counteracted by adopting redundant magnetic resistance and electric connection relation. The magnetic grating sensor is the most commonly used and basic one in the digital displacement sensor, is suitable for being applied in industrial environments such as water, oil, dust, high temperature and the like due to high vibration resistance and impact resistance, and has the advantages of simple structure, small volume and high precision, thus being widely applied.
The magnetic grating sensor is a displacement sensor for measuring displacement based on a magneto-resistance effect, and can measure displacement by utilizing the action of a magnetic field between a magnetic grating and a magnetic head. However, since the periodic arrangement of the magnetic poles of the magnetic grid causes the output signal of the magnetic head to be also in a periodic waveform, the existing magnetic grid sensing system cannot determine the absolute position (taking the starting point of the magnetic grid as a reference) of the magnetic head facing the magnetic grid at the first time when the detection system is started. To be able to measure absolute position at a first time, it is often necessary to add code channels, and to measure absolute position using the uniqueness of the spatially formed magnetic field between the code channels (e.g., using a multi-code channel position measurement system similar to the vernier caliper principle). But doing so increases the size of the position measurement system, which is unacceptable for application scenarios where the installation space of the position detection system is severely limited.
Disclosure of Invention
Aiming at the existing absolute position measurement system based on the magnetic grating, a plurality of code channels are required to act together with the magnetic head, so that the manufacturing difficulty of the magnetic grating is increased, the absolute position measurement system is oversized, and the specific application scene is difficult to meet. Therefore, the application improves the structure of the magnetic grid, adaptively develops a corresponding position calculation method, and provides an absolute position detection system of a single magnetic pole code channel, wherein the magnetic grid in the absolute position system has small size and low manufacturing difficulty.
The absolute position detection system provided by the application comprises a magnetic grid formed by alternately arranging N-S magnetic poles, a magnetic field sensing module (magnetic head) and a position calculation module.
Wherein, the magnetic poles of the magnetic grid have the same height and the same width in the arrangement direction to form an arithmetic array. The magnetic field sensing module is composed of four magnetic resistances R 1、R2、R3、R4 which are arranged at equal intervals on a plane parallel to the magnetic grid and have equal sensing coefficients. The sense directions of the magnetic resistances R 1、R2、R3、R4 are the same, and are all parallel/antiparallel to the magnetic pole arrangement direction of the magnetic gate. Reluctance R 1、R3 forms a first sensing half bridge, reluctance R 2、R4 forms a second sensing half bridge, and reluctance R 4、R3 is the upper half bridge arm of the corresponding sensing half bridge or the lower half bridge arm of the corresponding sensing half bridge. The type of magneto-resistance is XMR, which includes GMR, TMR, AMR.
The position calculation module is used for calculating (including matching) the absolute position of the magnetic field sensing module, which is opposite to the magnetic grid, according to the leading-out signal V 1 in the middle of the magnetic resistance R 1、R3 and the leading-out signal V 2 in the middle of the magnetic resistance R 2、R4.
Preferably, the distance L between two adjacent magnetic resistances in the magnetic resistances R 1、R2、R3、R4 is smaller than the minimum value of the magnetic pole width in the magnetic gate.
In some embodiments, the position calculation module matches the absolute position of the magnetic field sensing module opposite to the magnetic grid according to the detected extraction signal V 1、V2 and a pre-stored relation curve of the extraction signal V 1、V2 and the absolute position. The advantage of this embodiment is that the position matching process is simple and computationally inexpensive, but requires sufficient memory space to store the relationship of the outgoing signal V 1、V2 to the absolute position points on the magnetic grid.
In another embodiment, the position calculation module is based on the detected extraction signal V 1、V2 and the ratio of the pre-stored spacing L between two adjacent magnetoresistors to the width of each pole on the magnetic gridAnd calculating the absolute position of the magnetic field sensing module, which is opposite to the magnetic grid, wherein W i is the width of the ith magnetic pole of the magnetic grid, and i is a positive integer. The calculating the absolute position of the magnetic field sensing module facing the magnetic grid comprises the following steps of based on a resistance magnetic angle formulaV 1、V2 is obtained:
wherein, the A, B are physical parameters corresponding to the magnetic resistance itself respectively, and θ is a magnetic angle corresponding to the accurate position of the magnetic resistance R 1 closest to the initial side of the magnetic grid in the opposite magnetic resistance. Constructing an intermediate variable V a、Vb and a reference quantity C:
Pre-storing one by one Substituting the value of C into the calculation formula in the reference quantity C to be closest to the value of CCorresponding to (a)As the currentValues to further determine the absolute position of the magnetic field sensing module facing the magnetic grid. Through the steps, at least the magnetic field sensing module is opposite to which magnetic pole or which two magnetic poles of the magnetic grid.
Further, in order to determine the accurate position of the magnetic field sensing module at the opposite magnetic poles, the following process can be performed, namely, the value of C is closest to that of CCorresponding to (a)Respectively substituting each value of the (a) into an inverse trigonometric function: And determining the final value of theta according to the polarities of the two magnetic poles opposite to each other by the magnetic resistance in the magnetic field sensing module, thereby determining the accurate value of the absolute position. When the value of C is closest to Corresponding to (a)When the number of values of theta is two, and the number of values of theta is more than two, the correct value of theta can be screened according to the polarity of the magnetic pole of the magnetic grid opposite to the magnetic field sensing module determined in the previous part, and then the absolute position of the magnetic field sensing module taking the starting point of the magnetic grid as the reference point can be accurately obtained.
The absolute position measurement system provided by the application can realize absolute position detection based on the special arrangement of the magnetic poles in the single code channel and matching with a corresponding algorithm. The magnetic grid of the absolute position measuring system has a simple structure and a small size, and can well meet the application requirements of small installation space and low manufacturing cost of the absolute position measuring system.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are needed in the embodiments will be briefly described below, it being understood that the following drawings only illustrate some embodiments of the present application and therefore should not be considered as limiting the scope, and other related drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
Fig. 1 is a schematic structural diagram of an absolute position detecting system provided by the present application. .
Fig. 2a is a schematic waveform diagram of an output V 1、V2 of a two-way sensing half-bridge in an absolute position detecting system according to some embodiments of the present application.
FIG. 2b is a graph of the output of the two-way sense half-bridge at V 1、V2 two-dimensional coordinate plane corresponding to each absolute position point from FIG. 2 a.
Fig. 3 is a graph of the curve of fig. 2b after each point V 1、V2 is converted into a V a、Vb two-dimensional coordinate plane.
Detailed Description
For the purpose of making the objects, technical solutions and advantages of the embodiments of the present application more apparent, the technical solutions of the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application, and it is apparent that the described embodiments are only some embodiments of the present application, not all embodiments. The components of the embodiments of the present application generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations.
Thus, the following detailed description of the embodiments of the application, as presented in the figures, is not intended to limit the scope of the application, as claimed, but is merely representative of selected embodiments of the application. All other embodiments, which can be made by a person skilled in the art without making any inventive effort, are intended to be within the scope of the present application.
It should be noted that like reference numerals and letters refer to like items in the following figures, and thus once an item is defined in one figure, no further definition or explanation thereof is necessary in the following figures.
In the description of the present application, it should be noted that, directions or positional relationships indicated by terms such as "inner", "outer", "upper", "lower", "vertical", etc., are directions or positional relationships based on those shown in the drawings, or those that are conventionally put in use for the product of the application, are merely for convenience of describing the present application and simplifying the description, and do not indicate or imply that the apparatus or elements referred to must have a specific direction, be configured and operated in a specific direction, and thus should not be construed as limiting the present application. Furthermore, the terms "first," "second," "third," and the like are used merely to distinguish between descriptions and should not be construed as indicating or implying relative importance.
Some embodiments of the present application are described in detail below with reference to the accompanying drawings. Features of the embodiments described below may be combined with each other without conflict.
In the embodiment shown in fig. 1, the absolute position detection system provided by the present application includes a magnetic grid 1 formed by alternately arranging N-S magnetic poles, a magnetic field sensing module 2 (magnetic head), and a position calculating module 3 (not shown in fig. 1).
Wherein the magnetic poles (pitch) of the magnetic grid 1 have the same height and the same width in the arrangement direction to form an arithmetic array. As shown in fig. 1, the magnetic poles of the magnetic grid 1 have widths of 0.3mm, 0.32mm, 0.34mm, 0.36mm, respectively, from left to right, i.e., in this embodiment, the width difference between adjacent two magnetic poles is 0.02mm.
The magnetic field sensing module 2 (i.e., magnetic head) is located above the magnetic grid, separated from the plane of the magnetic grid 1 by an air gap (air gap). The magnetic field sensing module is composed of four magnetic resistances R 1、R2、R3、R4 which are arranged at equal intervals on a plane parallel to the magnetic grid and have equal sensing coefficients. In the embodiment shown in FIG. 1, the spacing between adjacent ones of the magnetoresistors R 1、R2、R3、R4 is 0.25mm. The sense directions of the magnetic resistances R 1、R2、R3、R4 are the same, and are all parallel/antiparallel to the magnetic pole arrangement direction of the magnetic gate. Reluctance R 1、R3 forms a first sensing half bridge, reluctance R 2、R4 forms a second sensing half bridge, and reluctance R 4、R3 is the upper half bridge arm of the corresponding sensing half bridge or the lower half bridge arm of the corresponding sensing half bridge. The type of magneto-resistance R 1、R2、R3、R4 in the magnetic field sensing module may be XMR, which includes GMR, TMR, AMR.
The position calculating module 3 is configured to calculate (or match) an absolute position of the magnetic field sensing module opposite to the magnetic grid according to the outgoing signal V 1 in the middle of the magnetic resistance R 1、R3 and the outgoing signal V 2 in the middle of the magnetic resistance R 2、R4.
Preferably, the distance L between two adjacent magnetic resistances in the magnetic resistances R 1、R2、R3、R4 is smaller than the minimum value of the magnetic pole width in the magnetic gate.
The waveforms of the outgoing signal V 1 in the middle of the reluctance R 1、R2, the outgoing signal V 2 in the middle of the reluctance R 3、R4 are shown in fig. 2a, corresponding to the embodiment shown in fig. 1. The outgoing signals V 1、V2 are "sine waves" with gradually increasing amplitudes, respectively, but are offset from each other. With the extraction signal V 1、V2 as two-dimensional coordinates of the plane, respectively, the extraction signal V 1、V2 exhibits a curve change as shown in fig. 2b (where the units of the abscissa and the ordinate are volts (V)) when the magnetic field sensing module 2 moves relative to the magnetic grid 1. Therefore, as long as the absolute positions of the coordinate points on the curve and the magnetic grid 1 corresponding to the magnetic field sensing modules 2 corresponding to the coordinate points are stored in advance, the absolute positions of the current magnetic field sensing modules 2 corresponding to the magnetic grid 1 can be directly matched according to the actually measured leading-out signals V 1、V2 by adopting a position calculation module in the follow-up process. Therefore, in some embodiments, the absolute position is obtained by the matching method, the process is simple, and the calculation amount is small.
In another embodiment, a slightly more computationally intensive algorithm may be used, based on the derived signal V 1、V2 in combination with the magnetic angle formulaThe absolute position of the magnetic field sensing module opposite to the magnetic grid is calculated, so that the situation that a large amount of storage space is needed to pre-store the leading-out signal V 1、V2 and the current magnetic field sensing module 2 opposite to the absolute position of the magnetic grid 1 under the condition that the length of the magnetic grid is longer and the number of magnetic poles is relatively large can be avoided.
In the other embodiment, the absolute position of the magnetic field sensing module facing the magnetic grid is calculated (or matched) according to the leading-out signal V 1 in the middle of the magnetic resistance R 1、R2 and the leading-out signal V 2 in the middle of the magnetic resistance R 3、R4, which is specifically implemented as follows:
The position calculation module is based on the detected leading-out signal V 1、V2 and the ratio of the pre-stored distance L between two adjacent magnetic resistances to the width of each magnetic pole on the magnetic grid And calculating the absolute position of the magnetic field sensing module, which is opposite to the magnetic grid. W i is the width of the ith magnetic pole of the magnetic grid, and i is a positive integer. Based on resistance magnetic angleV 1、V2 is obtained:
wherein, the A, B are physical parameters corresponding to the magnetic resistance itself respectively, and θ is a magnetic angle corresponding to the accurate position of the magnetic resistance R 1 closest to the initial side of the magnetic grid in the opposite magnetic resistance.
Then, calculating the absolute position of the magnetic field sensing module, which is opposite to the magnetic grid, by using the constructed intermediate variable V a、Vb and the constructed reference quantity C:
For the embodiment of fig. 2b, with the intermediate variable V a、Vb as two coordinate axes of the two-dimensional plane coordinate, V a、Vb exhibits a curve change as shown in fig. 3 (the coordinate units are volts (V)) when the magnetic field sensing module 2 moves relative to the magnetic grid 1.
Then, pre-stored one by oneSubstituting the value of C into the calculation formula in the reference quantity C to be closest to the value of CCorresponding to (a)As the currentValues to further determine the absolute position of the magnetic field sensing module facing the magnetic grid. At least which magnetic pole or which two magnetic poles of the magnetic grid are opposite to the magnetic field sensing module can be realized through the processing steps.
Further, to determine the exact location of the magnetic field sensing module at its facing pole, the following additional calculations may be performed:
The value of C is closest to Corresponding to (a)Respectively substituting each value of the (a) into an inverse trigonometric function: And determining the final value of theta according to the polarities of the two magnetic poles opposite to each other by the magnetic resistance in the magnetic field sensing module, thereby determining the accurate value of the absolute position. When the value of C is closest to Corresponding to (a)When the number of values of theta is two, and the number of values of theta is more than two, the correct value of theta can be screened according to the polarity of the magnetic pole of the magnetic grid opposite to the magnetic field sensing module determined in the previous part, and then the absolute position of the magnetic field sensing module taking the starting point of the magnetic grid as the reference point can be accurately obtained.
From the above, the absolute position measurement system provided by the application can realize absolute position detection on the premise of not adopting multiple magnetic code channels based on the special arrangement of the magnetic poles in the magnetic grid and the corresponding matching algorithm. The magnetic pole of the magnetic grid of the absolute position measuring system is simple in manufacturing process, the whole size of the magnetic grid is small, and the application requirements of small installation space and low manufacturing cost of the absolute position measuring system can be well met.
The above description is only of the preferred embodiments of the present application and is not intended to limit the present application, but various modifications and variations can be made to the present application by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the protection scope of the present application. It should be noted that like reference numerals and letters in the following figures denote like items, once an item is defined in one figure, no further definition or explanation thereof is necessary in the following figures.
Claims (7)
1. An absolute position detecting system comprises a magnetic grid formed by alternately arranging N-S magnetic poles, a magnetic field sensing module and a position calculating module, and is characterized in that,
The magnetic field sensing module consists of four magnetic resistances R 1、R2、R3、R4 which are arranged at equal intervals on a plane parallel to the magnetic grid and have equal sensing coefficients, the sensing directions of the magnetic resistances R 1、R2、R3、R4 are the same and are parallel/antiparallel to the arrangement direction of the magnetic grid magnetic poles, the magnetic resistance R 1、R3 forms a first sensing half bridge, the magnetic resistance R 2、R4 forms a second sensing half bridge, and the magnetic resistance R 4、R3 is the upper half bridge arm of the corresponding sensing half bridge or the lower half bridge arm of the corresponding sensing half bridge;
The position calculation module is used for calculating the absolute position of the magnetic field sensing module, which is opposite to the magnetic grid, according to the leading-out signal V 1 in the middle of the magnetic resistance R 1、R3 and the leading-out signal V 2 in the middle of the magnetic resistance R 2、R4.
2. The absolute position detecting system of claim 1, wherein a spacing L between adjacent ones of said magnetic resistances R 1、R2、R3、R4 is less than a minimum of a pole width in said magnetic grid.
3. The absolute position detection system according to claim 1 or 2, wherein the position calculation module matches the absolute position of the magnetic field sensing module facing the magnetic grid according to the detected extraction signal V 1、V2 and the pre-stored correspondence between the extraction signal V 1、V2 and the absolute position.
4. The absolute position detecting system according to claim 1 or 2, wherein said position calculating module is based on the detected extraction signal V 1、V2 and a ratio of a pre-stored spacing L between adjacent two magnetic resistances to a width of each magnetic pole on said magnetic gridAnd calculating the absolute position of the magnetic field sensing module, which is opposite to the magnetic grid, wherein W i is the width of the ith magnetic pole of the magnetic grid, and i is a positive integer.
5. The absolute position detection system of claim 4, wherein said calculating an absolute position of said magnetic field sensing module opposite said magnetic grid comprises a magnetoresistive-based magnetic angle formulaV 1、V2 is obtained:
wherein, the A, B is a physical parameter corresponding to the magnetic resistance itself, and θ is a magnetic angle corresponding to the accurate position of the magnetic resistance R 1 closest to the initial side of the magnetic grid in the opposite magnetic resistance;
Constructing an intermediate variable V a、Vb and a reference quantity C:
Pre-storing one by one Substituting the value of C into the calculation formula in the reference quantity C to be closest to the value of CCorresponding to (a)As the currentValues to further determine the absolute position of the magnetic field sensing module facing the magnetic grid.
6. The absolute position detecting system of, wherein said further determining the absolute position of said magnetic field sensing module facing said magnetic grid comprises causing C to take a value closest to when the number of poles of said magnetic field sensing module facing said magnetic grid is twoCorresponding to (a)When there are two values, byThe corresponding two values are respectively substituted into the inverse trigonometric function: And determining the final value of theta according to the polarities of the two magnetic poles opposite to each other by the magnetic resistance in the magnetic field sensing module, thereby accurately determining the absolute position.
7. Absolute position detecting system according to any of claims 1-6, wherein the type of magneto resistance is XMR, which XMR comprises GMR, TMR, AMR.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202510394928.0A CN120232331A (en) | 2025-03-31 | 2025-03-31 | An absolute position detection system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202510394928.0A CN120232331A (en) | 2025-03-31 | 2025-03-31 | An absolute position detection system |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN120232331A true CN120232331A (en) | 2025-07-01 |
Family
ID=96165820
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202510394928.0A Pending CN120232331A (en) | 2025-03-31 | 2025-03-31 | An absolute position detection system |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN120232331A (en) |
-
2025
- 2025-03-31 CN CN202510394928.0A patent/CN120232331A/en active Pending
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US6690159B2 (en) | Position indicating system | |
| JP6926209B2 (en) | Distance sensor | |
| CN112504305B (en) | Encoder, motor and method for detecting absolute position of encoder | |
| US11092461B2 (en) | Magnetic position sensor system and method | |
| CN108692743B (en) | Redundant fault detection apparatus and method | |
| CN109075690B (en) | Position encoder | |
| US7119534B2 (en) | Magnetic position sensor | |
| CN1940472B (en) | Absolute liner encoder | |
| US8290732B2 (en) | Absolute type linear encoder and method for adjusting position thereof | |
| JP6377817B2 (en) | Non-contact magnetic linear position sensor | |
| US10989566B2 (en) | Magnetic sensor system for measuring linear position | |
| WO2010124580A1 (en) | Position detecting device and signal processing device and method thereof | |
| CN101846487A (en) | Magnetic array position sensing device and positioning method thereof | |
| CN208399786U (en) | A kind of zoom lens controlled using voice coil motor | |
| Taghvaeeyan et al. | Magnetic sensor-based large distance position estimation with disturbance compensation | |
| CN120232331A (en) | An absolute position detection system | |
| CN108871248A (en) | A kind of absolute-type position detection device can be applied to super large stroke detection | |
| US10859399B2 (en) | Method and apparatus for magnetically sensing the position of a magnetic target | |
| CN110579224A (en) | A method and system for accurately measuring the displacement of a motor mover using a Hall sensor | |
| CN211346838U (en) | High-precision absolute position measuring system | |
| JP2003035564A (en) | Absolute position detection encoder and its origin detection method | |
| US7948230B2 (en) | Magnetic type digital-analogic position-sensing device | |
| CN120160519A (en) | A system for measuring absolute position | |
| US20250093144A1 (en) | Inductive position determination system with varying coil geometry, and corresponding position determination method | |
| CN109405725B (en) | Planar two-degree-of-freedom displacement measurement method based on magnetic field information |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |