A magnetic suspension micro-motion platform sensing system

Abstract

The present invention discloses a magnetic suspension micro-motion platform sensing system, comprising a composite light source; a coupler group, comprising one or more dichroic mirrors and at least one reference grating; one of the dichroic mirrors is used to separate the wide-band laser and the monochromatic laser generated by the composite light source, and the monochromatic laser forms diffracted light through the reference grating; the coupler group is relatively fixed to the base of the magnetic suspension micro-motion platform; a passive sensor group is fixedly mounted on the motion platform of the magnetic suspension platform; it comprises a fiber grating array and a plurality of scale gratings; the scale grating forms a moire fringe sensor with the corresponding reference grating, and the diffracted light of the reference grating forms moire fringe, which is received by the detector group and used for displacement and / or posture sensing of the motion platform. The present invention realizes comprehensive, real-time, and interference-free online monitoring of the micro-motion platform, and can perform high-precision real-time control of the magnetic suspension micro-motion working platform based on the monitoring data.

Description

Technical Field

[0001] The invention belongs to the field of precision machining, and more specifically, relates to a magnetic suspension micro-motion platform sensing system. Background Art

[0002] The magnetic suspension micro-motion workbench uses non-contact magnetic suspension drive technology for the motion platform and drive mechanism, eliminating the impact of friction and wear on motion accuracy, so it is easy to achieve large-scale high-precision micro-motion. The magnetic suspension micro-motion workbench has become a key equipment in the fields of precision manufacturing, micro-nano processing and high-precision measurement. Its unique non-contact control method and high sensitivity make it stand out in application scenarios that pursue high stability and high precision.

[0003] However, the performance of the magnetic levitation micro-motion workbench is deeply affected by the accuracy and reliability of its sensor system and position and posture measurement technology. Measuring the position, posture and stress distribution of the magnetic levitation micro-motion work platform is very necessary to evaluate the working state and environmental state of the magnetic levitation micro-motion work platform. However, the motion accuracy of the sub-suspension micro-motion work platform is at the micro-nano level. The current high-precision sensing system relies on electromagnetic signals, such as high-precision capacitive sensors and high-precision eddy current sensors. In a strong magnetic working environment, it may not only produce measurement errors, but also affect the control signal of the magnetic levitation work platform, introducing more electromagnetic influencing factors and increasing the difficulty of controlling the magnetic levitation work platform. Summary of the invention

[0004] In view of the above defects or improvement needs of the prior art, the present invention provides a magnetic levitation micro-motion platform sensing system, which aims to analyze the working parts and magnetic drive states respectively through passive fiber grating sensing and moiré fringe sensing, high-precision stress distribution measurement and posture sensing, so as to perform contact-free and interference-free sensing monitoring of the state of the magnetic levitation micro-motion platform, thereby solving the technical problems of contact interference and signal interference in the existing magnetic levitation micro-motion working platform sensing.

[0005] To achieve the above-mentioned object, according to one aspect of the present invention, a magnetic suspension micro-motion platform sensing system is provided, comprising a composite light source, a coupler group, a passive sensor group, and a detector group;

[0006] The composite light source is used to generate one or more monochromatic lasers and a wide-band composite collimated laser;

[0007] The coupler group includes one or more dichroic mirrors and at least one reference grating; one of the dichroic mirrors is used to separate the wide-band laser and the monochromatic laser generated by the composite light source, and the monochromatic laser forms diffracted light through the reference grating; the coupler group is relatively fixed to the base of the magnetic suspension micro-motion platform;

[0008] The passive sensor group is fixedly mounted on the motion platform of the magnetic levitation platform; it includes a fiber grating array and a plurality of scale gratings; the fiber grating array is used for vibration and / or stress sensing of the motion platform, receives a wide-band laser through spatial coupling, and its output light is spatially coupled to the detector group; the scale grating forms a moiré fringe sensor with a corresponding reference grating, and the diffracted light of the reference grating is formed into moiré fringe, which is received by the detector group and used for displacement and / or posture sensing of the motion platform;

[0009] The detector group receives the optical output signal of the passive sensor group and is relatively fixed to the base of the magnetic suspension micro-motion platform.

[0010] Preferably, in the magnetic levitation micro-motion platform sensing system, the composite light source is relatively fixed to the base of the magnetic levitation micro-motion platform.

[0011] Preferably, in the magnetic suspension micro-motion platform sensing system, the fiber Bragg grating is used as a stress sensor for the motion platform, and the grating areas of the array are evenly arranged on the lower surface of the magnetic suspension platform, and the direction of the fiber Bragg grating is parallel to the diagonal direction of the magnetic suspension platform.

[0012] Preferably, in the magnetic suspension micro-motion platform sensing system, when there are multiple dichroic mirrors, other dichroic mirrors are used to separate multiple monochromatic lasers.

[0013] Preferably, in the magnetic suspension micro-motion platform sensing system, the fiber Bragg grating is used as a stress sensor for the motion platform, and the grating areas of the array are evenly arranged on the lower surface of the magnetic suspension platform, and the direction of the fiber Bragg grating is parallel to the diagonal direction of the magnetic suspension platform.

[0014] Preferably, the magnetic suspension micro-motion platform sensing system has a coupling lens upstream of the fiber grating array incident end, and the coupling lens focuses the wide-band laser and couples it to the fiber grating array incident end.

[0015] Preferably, in the magnetic suspension micro-motion platform sensing system, the light output end of the fiber grating array has a coupling lens or the tail end is processed into a lens to couple the light output of the fiber grating array to the detector group.

[0016] Preferably, the fiber grating array of the magnetic suspension micro-motion platform sensing system has a suspended temperature compensation grating area.

[0017] Preferably, in the magnetic levitation micro-motion platform sensing system, the scale grating includes a first grating and a second grating, which form a secondary moiré fringe sensor with the reference grating, and the first grating and the second grating respectively diffract the diffracted light of the monochromatic laser P light and the diffracted light of the S light to form secondary moiré fringes.

[0018] Preferably, the magnetic levitation micro-motion platform sensing system, its detector group includes a spectrum analyzer and an array photodetector, the spectrum analyzer receives the output light of the fiber grating array, and is used to analyze the vibration and / or stress distribution of the motion platform; the array photodetector is used to detect moiré fringes to analyze the displacement and / or posture of the motion platform.

[0019] In general, the above technical solutions conceived by the present invention can achieve the following beneficial effects compared with the prior art:

[0020] The magnetic levitation micro-motion platform sensing system provided by the present invention adopts a fiber grating array sensor to analyze the effect of the working parts on the motion platform, and adopts a stripe moiré sensor to analyze the effect of the stator winding on the platform. Both are passive optical devices, and non-contact measurement is achieved through spatial coupling, thereby realizing comprehensive, real-time, and non-interference online monitoring of the micro-motion platform. Based on the monitoring data, the magnetic levitation micro-motion working platform can be controlled in real time with high precision. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a schematic structural diagram of a magnetic suspension micro-motion platform sensing system provided in an embodiment;

[0022] Figure 2 It is a schematic diagram of the installation of a fiber grating array of a magnetic suspension micro-motion platform sensing system provided in an embodiment;

[0023] Figure 3 This is a schematic diagram of the secondary moiré fringe generation principle of the magnetic levitation micro-motion platform provided in the embodiment.

[0024] In all the drawings, the same figure marks are used to represent the same elements or structures, wherein: 1 is a motion platform, 2 is a permanent magnet array, 3 is a stator winding, 4 is a conformal light source, 01 is a plane reflector, 02 is a right-angle prism, 03 is a polarization splitter prism, 51 is a first dichroic mirror, 52 is a second dichroic mirror, 53 is a third dichroic mirror, 61 is a fiber grating array, 611 is a stress sensing grating area, 612 is a temperature compensation grating area, 71 is a spectrum analyzer, 7 is an array detector, 72 is a first array detector, 73 is a second array detector, 74 is a third array detector, 81 is a reference grating, 82 is a first grating of the scale grating, and 83 is a second grating of the scale grating. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0026] A magnetically suspended micro-motion platform comprises a motion platform and a base; the motion platform has a permanent magnet array; the base has a stator winding arranged corresponding to the permanent magnet array, and the motion platform is driven to move by controlling the current of the stator winding. Analysis of the state sources that affect the magnetically suspended micro-motion platform includes two aspects: on the one hand, the influence of the working parts carried on the motion platform on the motion platform, including vibration and stress; on the other hand, the driving of the permanent magnet array by the stator winding. In the passive optical signal sensor based on optical signals, the present invention selects a fiber grating array to measure vibration and stress, analyzes the effect of the working parts on the platform on the motion platform, selects a stripe moiré sensor for position and rotation posture, and analyzes the effect of the stator winding on the motion platform.

[0027] The magnetic suspension micro-motion platform sensing system provided by the present invention comprises a composite light source, a coupler group, a passive sensor group, and a detector group;

[0028] The composite light source is used to generate one or more monochromatic lasers and a wide-band composite collimated laser; preferably, the composite light source is relatively fixed to the base of the magnetic suspension micro-motion platform;

[0029] The coupler group includes one or more dichroic mirrors and at least one reference grating; one of the dichroic mirrors is used to separate the wide-band laser and the monochromatic laser generated by the composite light source, and the other dichroic mirrors are used to separate multiple monochromatic lasers; the monochromatic laser forms diffracted light through the reference grating; the coupler group is relatively fixed to the base of the magnetic suspension micro-motion platform; considering the interaction between the electromagnetic signal sensor and the strong magnetic environment of the magnetic suspension micro-motion platform, the measurement is affected by the strong magnetic environment and deviates from the true value and brings more uncontrollable factors to the control of the magnetic suspension micro-motion platform, so a passive sensor based on optical signals is used to ensure the accuracy of the measurement and reduce the control difficulty, and the reliability is strong without power supply. However, if the optical sensor adopts an all-fiber optical path, the laser light source and the detector are inevitably integrated in the motion platform, and the signal of the detector inevitably needs to be output and analyzed through optical fiber or wire. This physical connection affects the motion of the motion platform. Since the motion accuracy of the motion platform is nanometer / micrometer level, the influence of the physical connection on the motion platform cannot be ignored. Therefore, the present invention adopts spatial coupling to realize optical signal transmission.

[0030] The passive sensor group is fixedly mounted on the motion platform of the magnetic suspension platform, and includes a fiber grating array and a plurality of scale gratings;

[0031] The fiber grating array receives wide-band lasers through spatial coupling, and its outgoing light is spatially coupled to the detector group for vibration and / or stress sensing of the motion platform; in a preferred embodiment, the fiber grating is used as a stress sensor for the motion platform, and the grating area of ​​the array is evenly arranged on the lower surface of the magnetic levitation platform, and the direction of the fiber grating is parallel to the diagonal direction of the magnetic levitation platform. Specifically: upstream of the incident end of the fiber grating array, there is a coupling lens, which focuses the wide-band laser and couples it to the incident end of the fiber grating array; the light-emitting end of the fiber grating array has a coupling lens or the tail end is processed into a lens to couple the light output of the fiber grating array to the detector group. Preferably, the fiber grating array has a temperature compensation grating area that is suspended.

[0032] The scale grating forms a moiré fringe sensor with the corresponding reference grating, and the diffracted light of the reference grating forms moiré fringe, which is received by the detector group and used for displacement and / or posture sensing of the motion platform; in a preferred embodiment, the scale grating includes a first grating and a second grating, which form a secondary moiré fringe sensor with the reference grating, and the first grating and the second grating respectively diffract the diffracted light of the monochromatic laser P light and the diffracted light of the S light to form secondary moiré fringe;

[0033] The detector group receives the optical output signal of the passive sensor group and is relatively fixed to the base of the magnetic levitation micro-motion platform; specifically, the detector group includes a spectrum analyzer and a planar array photoelectric detector, the spectrum analyzer receives the output light of the fiber grating array and is used to analyze the vibration and / or stress distribution of the motion platform; the planar array photoelectric detector is used to detect moiré fringes to analyze the displacement and / or posture of the motion platform.

[0034] It should be noted that when spatial coupling is used for optical signal transmission, when the number of sensors is large, the difficulty of optical coupling between the light source and the sensor increases sharply. Therefore, the present invention adopts a composite laser light source, and the optical device integrated on the motion platform is calibrated with the composite laser light source. Only one calibration is required to achieve the coupling of all optical signals, thereby reducing the difficulty of coupling. The preferred solution is to use a coupler group as a coupling with the composite laser light source, and a dichroic mirror is used to separate the input light sources of different sensors. The dichroic mirror is calibrated with the reference grating, and the relative positions of the passive sensor groups integrated on the motion platform are pre-calibrated, and a one-to-many coupling between the laser light source and the sensor group is achieved through the coupler. Since the detector group does not need to be fixed to the motion platform, a larger detection range can be used, and the requirements for spatial coupling accuracy are low. Therefore, the spatial coupling between the detector group and the sensor group of the present invention adopts a one-to-one corresponding coupling.

[0035] The following are examples:

[0036] The magnetic suspension micro-motion platform sensing system provided in this embodiment is as follows: Figure 1As shown, it is applied to the magnetic suspension micro-motion working platform, and four groups of permanent magnet arrays are respectively embedded in the middle of the four sides of the bottom surface of the motion platform, and four groups of stator windings are arranged correspondingly, including: a composite light source, a coupler group, a passive sensor group, and a detector group;

[0037] The composite light source is used to generate three short-wave monochromatic lasers and a long-wave wide-band composite collimated laser; the composite light source is relatively fixed to the base of the magnetic suspension micro-motion platform;

[0038] The coupler group is relatively fixed to the base of the magnetic suspension micro-motion platform, and includes three dichroic mirrors and three reference gratings; wherein the first dichroic mirror is used to separate the wide-band laser and the monochromatic laser generated by the composite light source, the second dichroic mirror is used to separate the blue light from the other two short-wave monochromatic lasers, and the third dichroic mirror is used to separate the cyan light from the violet light;

[0039] The wide-band laser is irradiated on the plane reflector; the blue light forms diffraction light through the first reference grating; the cyan light forms diffraction light through the second reference grating; and the purple light forms diffraction light through the right-angle prism and the third reference grating.

[0040] The passive sensor group is fixedly mounted on the motion platform of the magnetic suspension platform, and includes a fiber grating array and three scale gratings;

[0041] The wide-band laser is reflected by a plane mirror and enters a coupling lens, and the coupling lens focuses the wide-band laser on the incident end of the fiber grating array; the fiber grating array is glued and fixed on the bottom surface of the motion platform, such as Figure 2 As shown, the stress sensing grating area of ​​the fiber Bragg grating is arranged along the diagonal and in parallel with the diagonal, the temperature compensation grating area connected in series with the fiber Bragg grating array is suspended, the light end of the fiber Bragg grating array is ground into a focusing lens, and is connected to the detection light source through spatial coupling and coupled to the spectrum analyzer; a stress sensor for a motion platform.

[0042] The scale grating and the corresponding reference grating form a moiré fringe sensor, and the diffracted light of the reference grating is formed into moiré fringes, which are respectively arranged at the two ends of one side of the motion platform and in the middle of the opposite side. The blue moiré fringes are received by the first array detector and the detector group for analyzing the motion displacement of the scale grating; the cyan moiré fringes are received by the second array detector for analyzing the motion displacement of the scale grating; and the purple moiré fringes are received by the third array detector for analyzing the rotation angle of the scale grating.

[0043] The scale grating, such as Figure 3 As shown, it includes a first grating and a second grating, which form a secondary moiré fringe sensor with a reference grating, wherein the first grating and the second grating respectively diffract the diffracted light of the monochromatic laser P light and the diffracted light of the S light to form secondary moiré fringes;

[0044] The detector group includes a spectrum analyzer, a first array photoelectric detector, a second array photoelectric detector, and a third array detector. The spectrum analyzer receives the output light of the fiber grating array to analyze the stress distribution of the motion platform; the array photoelectric detector is used to detect moiré fringes to analyze the displacement or posture of the motion platform.

[0045] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A magnetic suspension micro-motion platform sensing system, characterized in that: It includes a composite light source, a coupler group, a passive sensor group, and a detector group; The composite light source is used to generate one or more monochromatic lasers and a wide-band composite collimated laser; The coupler group includes one or more dichroic mirrors and at least one reference grating; one of the dichroic mirrors is used to separate the wide-band laser and the monochromatic laser generated by the composite light source, and the monochromatic laser forms diffracted light through the reference grating; the coupler group is relatively fixed to the base of the magnetic suspension micro-motion platform; The passive sensor group is fixedly mounted on the motion platform of the magnetic levitation platform; it includes a fiber grating array and a plurality of scale gratings; the fiber grating array is used for vibration and / or stress sensing of the motion platform, receives a wide-band laser through spatial coupling, and its output light is spatially coupled to the detector group; the scale grating forms a moiré fringe sensor with a corresponding reference grating, and the diffracted light of the reference grating is formed into moiré fringe, which is received by the detector group and used for displacement and / or posture sensing of the motion platform; The detector group receives the optical output signal of the passive sensor group and is relatively fixed to the base of the magnetic suspension micro-motion platform.

2. The magnetic suspension micro-motion platform sensing system according to claim 1, characterized in that: The composite light source is relatively fixed to the base of the magnetic suspension micro-motion platform.

3. The magnetic suspension micro-motion platform sensing system according to claim 1, characterized in that: The fiber grating is used as a stress sensor for a motion platform, and the grating areas of its array are evenly arranged on the lower surface of the magnetic suspension platform, and the direction of the fiber grating is parallel to the diagonal direction of the magnetic suspension platform.

4. The magnetic suspension micro-motion platform sensing system according to claim 1, characterized in that: When multiple dichroic mirrors are present, other dichroic mirrors are used to separate multiple monochromatic lasers.

5. The magnetic suspension micro-motion platform sensing system according to claim 1, characterized in that: The fiber grating is used as a stress sensor for a motion platform, and the grating areas of its array are evenly arranged on the lower surface of the magnetic suspension platform, and the direction of the fiber grating is parallel to the diagonal direction of the magnetic suspension platform.

6. The magnetic suspension micro-motion platform sensing system according to claim 1, characterized in that: A coupling lens is disposed upstream of the incident end of the fiber grating array, and the coupling lens focuses the broadband laser and couples the laser to the incident end of the fiber grating array.

7. The magnetic suspension micro-motion platform sensing system according to claim 1, characterized in that: The light output end of the fiber grating array has a coupling lens or the tail end is processed into a lens to couple the light output of the fiber grating array to the detector group.

8. The magnetic suspension micro-motion platform sensing system according to claim 1, characterized in that: The fiber grating array has a suspended temperature compensation grating area.

9. The magnetic suspension micro-motion platform sensing system according to claim 1, characterized in that: The scale grating includes a first grating and a second grating, which form a secondary moiré fringe sensor with a reference grating. The first grating and the second grating respectively diffract the diffracted light of the monochromatic laser P light and the diffracted light of the S light to form secondary moiré fringes.

10. The magnetic suspension micro-motion platform sensing system according to claim 1, characterized in that: The detector group includes a spectrum analyzer and a planar array photoelectric detector. The spectrum analyzer receives the output light of the fiber grating array and is used to analyze the vibration and / or stress distribution of the motion platform; the planar array photoelectric detector is used to detect moiré fringes to analyze the displacement and / or posture of the motion platform.

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