A method for resisting electromagnetic interference using moiré fringes in metrology

Abstract

This invention relates to the field of photoelectric displacement precision measurement technology, and particularly to a method for resisting electromagnetic interference (EMI) in metrology using moiré fringes. The method includes the following steps: S1, determining the signal acquisition time interval Δt; S2, acquiring a signal at time t1, denoted as S1; S3, after waiting for Δt, acquiring a signal at time t2, denoted as S2; S4, after waiting for Δt, acquiring a signal at time t3, denoted as S3; S5, calculating the value of S based on the values ​​of S1, S2, and S3 using a weighted voting method, thus obtaining the signal S and achieving EMI resistance. This method requires no changes to the original circuit design, does not add components for electromagnetic shielding, saves costs, and uses micro-processor software in the photoelectric encoder or grating ruler processing circuit to improve EMI resistance. This method also saves on electromagnetic shielding procedures and reduces workload.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of photoelectric displacement precision measurement, and in particular to a method for resisting electromagnetic interference of a Moiré fringe for metrology, a computer device capable of executing the method, and a computer readable storage medium. BACKGROUND

[0002] The main application form of the Moiré fringe technology for metrology is a grating ruler for length measurement and an optical encoder for angle measurement, which are measurement devices integrating light, machine and electricity, and are widely used due to high precision, stable and reliable operation and fast response speed. The optical encoder and the grating ruler are often used with high-power components such as servo motors, and such components are prone to generate short-period pulse electromagnetic interference, which seriously affects the Moiré fringe signal and causes the optical encoder or the grating ruler to output incorrect measurement data, so that the optical encoder or the grating ruler cannot be used.

[0003] Currently, there are two main methods for resisting electromagnetic interference: the first method is to keep away from high-power components, and the second method is to make electromagnetic shielding. The first method cannot be implemented due to limited space of the device, and the second method has problems of large volume, high cost, easy leakage and difficult maintenance. SUMMARY

[0004] To solve the above problems, the present application provides a method for resisting electromagnetic interference of a Moiré fringe for metrology, so as to solve the shortcomings of the prior art, such as limited space, large volume, high cost, easy leakage and difficult maintenance.

[0005] The present application provides a method for resisting electromagnetic interference of a Moiré fringe for metrology, which comprises the following steps:

[0006] S11, determining a time interval △t for signal acquisition;

[0007] S22, acquiring a signal at t1 and recording it as S1;

[0008] S33, waiting for △t, and then acquiring a signal at t2 and recording it as S2;

[0009] S44, waiting for △t, and then acquiring a signal at t3 and recording it as S3;

[0010] S55, calculating the value of S according to the values of S1, S2 and S3 in a voting weighted manner to obtain a signal S, and resisting electromagnetic interference.

[0011] Preferably, in S11, the time interval △t for signal acquisition is determined according to the maximum rotation speed of the optical encoder or the fastest running speed of the grating ruler.

[0012] Preferably, the formula for determining the acquisition time interval Δt according to the maximum rotation speed of the photoelectric encoder or the fastest running speed of the grating ruler is:

[0013]

[0014] ω max is the maximum rotation speed of the photoelectric encoder or the fastest running speed of the grating ruler; n is the number of fine code lines of the photoelectric encoder or the number of fine code lines of the grating ruler.

[0015] Preferably, the formula for determining the acquisition time interval Δt according to the maximum rotation speed of the photoelectric encoder or the fastest running speed of the grating ruler is:

[0016] Δt≥W N ;

[0017] W N is the pulse width of the noise.

[0018] Preferably, the formula for determining the acquisition time interval Δt according to the maximum rotation speed of the photoelectric encoder or the fastest running speed of the grating ruler is:

[0019]

[0020] ω max is the maximum rotation speed of the photoelectric encoder or the fastest running speed of the grating ruler; n is the number of fine code lines of the photoelectric encoder or the number of fine code lines of the grating ruler; W N is the pulse width of the noise.

[0021] Preferably, in the S55, the formula for calculating the value of S in the voting weighted manner is:

[0022]

[0023] In the formula, num represents the number of S1, S2 and S3 equal to 1.

[0024] The application further provides a computer device, comprising:

[0025] at least one processor; and

[0026] a memory in communication connection with the at least one processor; wherein

[0027] the memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor to enable the at least one processor to execute the electromagnetic interference resistant method for measuring Moire fringes.

[0028] The application further provides a non-transient computer readable storage medium storing computer instructions for causing a computer to execute the method for anti-electromagnetic interference of Moire fringes for metrology.

[0029] Compared with the prior art, the application has the following beneficial effects:

[0030] The method for anti-electromagnetic interference of Moire fringes for metrology provided by the application does not change the original circuit design of the photoelectric encoder or the grating ruler, does not increase components for electromagnetic shielding, determines the sampling time interval of the microcontroller (DSP or FPGA) by using the highest rotating speed of the photoelectric encoder or the highest running speed of the grating ruler, respectively collects signal values at three sampling time points, and judges whether the signal is electromagnetic interference or a Moire fringe signal in a voting and weighting manner.

[0031] The method for anti-electromagnetic interference of Moire fringes for metrology provided by the application fully utilizes the highest rotating speed and running speed parameters of the photoelectric encoder or the grating ruler, does not need to change the original circuit design, does not increase components for electromagnetic shielding, saves costs, uses the single-chip microcomputer (or ARM), DSP and FPGA and other small processors in the photoelectric encoder or grating ruler processing circuit software, improves the anti-electromagnetic interference capability, and saves the electromagnetic shielding process and reduces the workload. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 It is a schematic diagram of a hardware circuit used in the embodiment of the application;

[0033] Figure 2 It is a comparison diagram of square wave signals and coarse code signals with and without short-period pulse electromagnetic noise interference in the embodiment of the application;

[0034] Figure 3 It is a schematic diagram of eliminating short-period pulse noise interference in the embodiment of the application;

[0035] Figure 4 It is a flowchart of the method for anti-electromagnetic interference of Moire fringes for metrology in the embodiment of the application;

[0036] Figure 5 It is a block diagram of an exemplary computer device suitable for implementing the embodiment of the application. DETAILED DESCRIPTION

[0037] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and do not constitute a limitation thereof.

[0038] like Figure 4 The diagram shown is a flowchart illustrating a method for resisting electromagnetic interference using moiré fringes in metrology, according to a specific embodiment of the present invention. As can be seen from the diagram, this invention provides a method for resisting electromagnetic interference using moiré fringes in metrology, the method comprising the following steps:

[0039] S11. Determine the signal acquisition time interval Δt; specifically, determine the signal acquisition time interval Δt based on the maximum speed of the photoelectric encoder or the fastest running speed of the grating ruler.

[0040] In a preferred embodiment, the formula for determining the acquisition time interval Δt based on the maximum speed of the photoelectric encoder or the fastest running speed of the grating ruler is Equation (2):

[0041]

[0042] ω max is the maximum speed of the photoelectric encoder, or the fastest operating speed of the grating ruler; n is the number of fine code lines on the photoelectric encoder, or the number of fine code lines on the grating ruler; W N The pulse width of the noise;

[0043] S22. Acquire the signal at time t1, and denote it as S1;

[0044] S33. After waiting for Δt, at time t2, the signal is collected and recorded as S2;

[0045] S44. After waiting for Δt, at time t3, the signal is collected and recorded as S3;

[0046] S55. Based on the values ​​of S1, S2 and S3, the value of S is calculated using a voting weighting method to obtain the signal S, thereby achieving electromagnetic interference resistance.

[0047] In a specific embodiment of the present invention, based on the different original markings and rotation speeds of each encoder and the different running speeds of the grating ruler, a specific sampling time interval Δt is creatively set, and a three-stage sampling voting method is used to process the signal to achieve electromagnetic interference suppression, thus providing a method for electromagnetic interference suppression of moiré fringes for measurement.

[0048] In specific implementation methods, such as Figure 1As shown in the figure, the circuit is the processing circuit of the optical encoder or grating ruler, without any component added.

[0049] In the circuit in the embodiment, the core components are the shaping circuit, AD and microprocessor (ARM, DSP or FPGA), wherein the shaping circuit and AD can be integrated in the microprocessor with comparator interruption and ADC collection. The light emitted by the light-emitting diode passes through the code disc and grating, and then passes through the photoelectric receiving diode to convert the coarse code and fine code (Moller fringe) into voltage through the digital potentiometer. The control of the digital potentiometer is realized by the microcontroller. For the absolute grating ruler and optical encoder, the electromagnetic interference mainly acts on the coarse code, and then the coarse code decoding causes functional error. For the incremental and quasi-absolute optical encoder, the electromagnetic interference mainly affects the fine code shaping square wave used for counting, thereby causing counting error and causing code skipping. And for the subdivided fine code signal, the sin+ and sin- data are differentiated, and the cos+ and cos- data are differentiated in the microprocessor, so that the electromagnetic interference mixed in the sin+, sin-, cos+ and cos- signals is reduced, and thus the subdivision result is not affected.

[0050] As shown in the figure, the circuit is the processing circuit of the optical encoder or grating ruler, without any component added. Figure 2 As shown in the figure, the circuit is the processing circuit of the optical encoder or grating ruler, without any component added.

[0051]

[0052] Wherein, ω max is the maximum rotation speed of the optical encoder or the fastest running speed of the grating ruler, and n is the fine code line number of the optical encoder or grating ruler; the faster the running speed of the optical encoder or grating ruler, the denser the line, and the smaller the value of △t.

[0053] In the embodiment, △t is greater than or equal to the pulse width of the noise, that is: △t≥w N , w N is the pulse width of the noise; therefore, the value range of △t is preferably shown in the following formula (2):

[0054]

[0055] As shown in the figure, the circuit is the processing circuit of the optical encoder or grating ruler, without any component added. Figure 3The diagram shown is a schematic of eliminating short-period pulse noise interference in a specific embodiment of the present invention. In the specific embodiment, the value of signal S at time t1 is denoted as S1, the value at time t2 is denoted as S2, and the value at time t3 is denoted as S3; S1, S2, and S3 together determine the subsequent value of signal S.

[0056] In a specific implementation, the formula for calculating the value of S according to the voting weighting method is shown in equation (3):

[0057]

[0058] In the formula, num represents the number of S1, S2 and S3 that are equal to 1. For example, when S1 = 1, S2 = 0 and S3 = 1, according to the formula, num = 2 and S = 1.

[0059] Table 1

[0060] Serial number [S1] [S2] [S3] S 1 0 0 0 0 2 0 0 1 0 3 0 1 0 0 4 1 0 0 0 5 1 0 1 1 6 1 1 0 1 7 0 1 1 1 8 1 1 1 1

[0061] In the specific implementation, as shown in Table 1, the value of signal S is the weighted average of S1, S2, and S3, i.e., majority rule applies. The short-period pulse interference in signal S after processing by this method has been eliminated and can be used for subsequent processing.

[0062] Accordingly, according to embodiments of the present invention, the present invention also provides a computer device, a readable storage medium, and a computer program product.

[0063] Figure 5 This is a schematic diagram of the structure of a computer device 12 provided in an embodiment of the present invention. Figure 5 A block diagram of an exemplary computer device 12 suitable for implementing embodiments of the present invention is shown. Figure 5 The computer device 12 shown is merely an example and should not impose any limitation on the functionality and scope of use of the embodiments of the present invention.

[0064] like Figure 5 As shown, computer device 12 is represented in the form of a general-purpose computing device. Computer device 12 is intended to represent various forms of digital computers, such as laptop computers, desktop computers, workstations, personal digital assistants, servers, blade servers, mainframe computers, and other suitable computers. Electronic devices can also represent various forms of mobile devices, such as personal digital processors, cellular phones, smartphones, wearable devices, and other similar computing devices. The components shown herein, their connections and relationships, and their functions are merely illustrative and are not intended to limit the implementation of the invention described and / or claimed herein.

[0065] The components of the computer device 12 may include, but are not limited to: one or more processors or processing units 16, system memory 28, and bus 18 connecting different system components (including system memory 28 and processing unit 16).

[0066] Bus 18 represents one or more of several bus architectures, including a memory bus or memory controller, a peripheral bus, a graphics acceleration port, a processor, or a local bus using any of the various bus architectures. For example, these architectures include, but are not limited to, the Industry Standard Architecture (ISA) bus, the Micro Channel Architecture (MAC) bus, the Enhanced ISA bus, the Video Electronics Standards Association (VESA) local bus, and the Peripheral Component Interconnect (PCI) bus.

[0067] Computer device 12 typically includes a variety of computer system readable media. These media can be any available media that can be accessed by computer device 12, including volatile and non-volatile media, removable and non-removable media.

[0068] System memory 28 may include computer system readable media in the form of volatile memory, such as random access memory (RAM) 30 and / or cache memory 32. Computer device 12 may further include other removable / non-removable, volatile / non-volatile computer system storage media. By way of example only, storage system 34 may be used to read and write non-removable, non-volatile magnetic media (…). Figure 5 Not shown; usually referred to as a "hard drive"). Although Figure 5 Not shown, a disk drive for reading and writing to a removable non-volatile disk (e.g., a "floppy disk") and an optical disk drive for reading and writing to a removable non-volatile optical disk (e.g., a CD-ROM, DVD-ROM, or other optical media) may be provided. In these cases, each drive may be connected to bus 18 via one or more data media interfaces. Memory 28 may include at least one program product having a set (e.g., at least one) of program modules configured to perform the functions of the embodiments of the present invention.

[0069] A program / utility 40 having a set (at least one) of program modules 42 may be stored, for example, in memory 28. Such program modules 42 include, but are not limited to, an operating system, one or more application programs, other program modules, and program data. Each or some combination of these examples may include an implementation of a network environment. Program modules 42 typically perform the functions and / or methods described in the embodiments of the present invention.

[0070] Computer device 12 can also communicate with one or more external devices 14 such as a keyboard, a pointing device, a display 24, etc.; one or more devices that enable a user to interact with computer device 12; and / or any devices (e.g., network card, modem, etc.) that enable computer device 12 to communicate with one or more other computing devices. Such communication can occur via Input / Output (I / O) interface(s) 22. Still yet, computer device 12 can communicate with one or more networks, such as a local area network (LAN), a general wide area network (WAN), and / or a public network such as the Internet, via network adapter 20.

[0071] As shown, network adapter 20 communicates with the other components of computer device 12 via bus 18. It should be appreciated that although not shown, other hardware and / or software modules could be used in connection with computer device 12. These include, but are not limited to, microcode, device drivers, redundant processing units, external disk drive arrays, RAID systems, tape drives, and data archival storage systems, etc. Figure 5

[0072] Processing unit 16 can execute instructions stored in system memory 28 to perform various functions as described herein, including implementing the method for anti-electromagnetic interference of moire fringes for metrology.

[0073] The application also provides a non-transitory computer readable storage medium having stored thereon computer instructions, wherein the computer program is executed by a processor to implement the method for anti-electromagnetic interference of moire fringes for metrology.

[0074] The computer storage media of the present application can be any available media that can be accessed by a computer. By way of example, and not limitation, such computer readable media can comprise RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to carry or store desired computer program code in the form of instructions or data structures and that can be accessed by a computer. Also, any connection is properly termed a computer readable medium. For example, if the software is transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, or twisted pair, then the coaxial cable, fiber optic cable, or twisted pair are included in the definition of medium. Disk and disc, as used herein, includes compact disc (CD), laser disc, optical disc, Blu-ray® disc, etc. Thus, computer readable medium can now include a single medium, or multiple media (physical and / or logical), and / or transitory signals.

[0075] ​A computer readable signal medium can include a propagated data signal with computer executable prograrn code embodied therein, for example, in baseband or as part of a carrier wave. Such a propagated signal can take any of a variety of forms, including, but not limited to, electro-magnetic, optical, or any suitable combination thereof. A computer readable signal medium can be any computer readable medium that can be

[0076] Program code embodied on a computer readable medium can be transmitted using any appropriate medium, including but not limited to wireless, wire line, optical fiber cable, RF, etc., or any suitable combination of the foregoing. Computer program code for carrying out operations for aspects of the present application can be written in any suitable programming language including object oriented programming languages such as Java, Smalltalk, C++ or the like, conventional procedural programming languages, such as the "C" programming language or similar programming languages. The program code can execute entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer or entirely on the remote computer or server. In the latter scenario, the remote computer can be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or the connection can be made to an external computer (for example, through the Internet using an Internet Service Provider). These network connections are

[0077] An embodiment of the present application further provides a computer program product, comprising a computer program, which, when executed by a processor, implements the method for anti-electromagnetic interference of Moire fringes for metrology according to the above.

[0078] It should be understood that various forms of flow shown above can be used, with steps reordered, added, or removed. For example, steps recited in the present disclosure can be performed in parallel, in series, or in a different order, without limitation herein, so long as the desired results of the technical solutions of the present disclosure are achieved.

[0079] The above detailed description does not constitute a limitation on the protection scope of the present application. It should be understood by those skilled in the art that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modification, equivalent replacement, and improvement within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method of countering electromagnetic interference with Moire fringes for metrology, characterized in that, The anti-electromagnetic interference method comprises the steps of: S11. Determining a time interval for signal acquisition ; determining the acquisition time interval from the maximum rotational speed of the optical encoder or the fastest running speed of the grating scale The formula is: ； is the highest rotational speed of the optical encoder, or the fastest running speed of the grating ruler; is the number of fine code lines of the optical encoder, or the number of fine code lines of the grating ruler; is the pulse width of the noise; S22, in the moment, denoted as ; S33, waiting after a time duration, at a time, a signal is collected, denoted as ; S44, waiting after a time duration, at a time, a signal is collected, denoted as ; S55、according to 、 and the value of S is calculated by voting weighting, and the signal is obtained, and electromagnetic interference is resisted; in the S55, the formula for calculating the value of S by voting weighting is: In the formula, num represents the number of 1 in S1, S2 and S3.

2. A computer device, comprising: Comprise: At least one processor; And The memory is in communication connection with the at least one processor; wherein, The memory stores instructions executable by the at least one processor, and the instructions are executed by the at least one processor to enable the at least one processor to perform the anti-electromagnetic interference method for the moire fringe for metrology of claim 1.

3. A non-transitory computer-readable storage medium having stored thereon computer instructions, wherein, The computer instructions are used to enable the computer to perform the anti-electromagnetic interference method for the moire fringe for metrology of claim 1.

Images