Satellite-borne high-precision photoelectric encoder measurement result high fault-tolerance design method and system

Abstract

The application provides a kind of high-precision photoelectric encoder measurement result high fault-tolerant design method and system on satellite, comprising: by radial transceiving light path double-channel design, obtain two-way absolute angle data and two-way incremental data, four-way measurement data output angle data according to predetermined judgment rule, judgment rule is suitable for single point failure to output correct data, when multiple faults occur, according to the specific situation analysis, the judgment rule can be avoided to avoid the fault state and change to obtain correct angle data output, realize automatic fault-tolerant design.

Description

Technical Field

[0001] This invention relates to the field of spaceborne high-precision photoelectric encoder technology, specifically to a high-fault-tolerant design method and system for spaceborne high-precision photoelectric encoder measurement results. Background Technology

[0002] With the rapid development of satellite laser communication technology, the divergence angle of laser signal light is on the order of tens of microradians, which puts forward high requirements for the pointing accuracy of laser communication. The code resolution of high-precision photoelectric encoders can be within arcseconds, so they are widely used in the field of satellite laser communication or in fields with high-precision measurement or control requirements.

[0003] High-precision photoelectric encoders include absolute photoelectric encoders and incremental photoelectric encoders. Absolute photoelectric encoders can immediately acquire angular position data, making them convenient and reliable in application. Incremental photoelectric encoders, however, suffer from drawbacks such as loss of position information after power failure, requiring a reference point (zero mark) to be relied upon after power restoration and a zero-return operation to obtain the absolute position, and continuous accumulation of errors after incremental data anomalies. Therefore, absolute photoelectric encoders are now the primary application in the aerospace laser communication field.

[0004] The absolute photoelectric encoder has more than a dozen angle detection channels, which are intuitively divided into coarse code, medium code, fine code channels and a through-coil code channel. The light from the light source in the photoelectric encoder passes through the grating slits of each channel of the code disk to reach the photoelectric receiver and is converted into an electrical signal. This electrical signal is compared with the through-coil level to obtain digital signal data. After combining and logically processing the digital signal data of each channel, the angle information is obtained and the current absolute angle measurement data is directly output.

[0005] A fault in any channel of a high-precision absolute photoelectric encoder will cause errors in angle measurement results. A fault in the entire code track will also lead to incorrect angle measurement results. Furthermore, due to the size and weight limitations of satellite products, spaceborne high-precision photoelectric encoders are small in size and require high angle measurement accuracy. Therefore, the width of a single grating in the medium-precision and high-precision code channels reaches the range of 1mm to 0.1mm. Even tiny, invisible foreign objects adhering to the gratings on the channels can cause angle measurement errors. Therefore, foreign objects are strictly controlled throughout the entire product manufacturing and assembly process. However, if a small amount of uncleaned foreign objects are present, they may adhere to any code track on the optical code disk, seriously affecting the product's use. The optical code disk design should consider various failure modes, especially the potential for single-point failures that affect the accuracy of angle measurement, possessing fault tolerance and improving product reliability.

[0006] In the field of satellite high-precision photoelectric encoder technology, according to the patents retrieved, there are already photoelectric encoder design methods that carry out fault-tolerant design, but all of them currently have single-point failures. Given the technical characteristics of aerospace products that cannot be repaired on orbit, it is urgent to solve the technical problem of avoiding single-point failures that affect the accuracy of angle measurement function and improving product reliability.

[0007] Patent document CN110654573B (application number: 201910859072.4) discloses a single-point reliability redundancy method for satellite photoelectric encoders. This invention proposes acquiring absolute angle data, incremental angle data, and intermediate-precision code incremental data. If the absolute angle data equals the incremental angle data, the photoelectric encoder outputs the absolute angle data. If the absolute angle data does not equal the incremental angle data due to an anomaly in the precision code channel, the photoelectric encoder outputs intermediate-precision code incremental data. If the absolute angle data does not equal the incremental angle data due to an anomaly in the coarse code channel or intermediate-precision code channel, the photoelectric encoder outputs the incremental angle data. While the angle data output by this invention is correct after an anomaly in the precision code channel, its accuracy is reduced, failing to meet the requirements for high-precision angle measurement. Furthermore, this invention is limited to abnormal backups of individual code channels and does not identify anomalies in the entire code channel, still leaving a single point of failure affecting the accuracy of the angle measurement function.

[0008] Patent document CN108981765B (application number: 201810845722.5) discloses a fault-tolerant design method for the measurement channel of an absolute photoelectric encoder. This method can automatically correct errors within a full cycle and output correct angle data upon initial power-up, provided that the precision code channels J1 and J2, the intermediate precision code channel A13, and at least one of the channels A1 to A8 are functioning correctly. However, if any one of the precision code channels J1 and J2 or the intermediate code channel A13 fails, correct measurement data cannot be output. This design method suffers from a single point of failure that affects the accuracy of the angle measurement function.

[0009] Patent document CN204027519U (application number: 201420116688.5) discloses a photoelectric encoder position tester. It uses a photoelectric encoder signal processing module, a data conversion module, and an FPGA digital signal processing module to collaboratively complete the shaping, amplification, and subdivision of the data signal. The output LCD drive signal has high accuracy, and the electrical position of the photoelectric encoder is displayed in real time on an LCD screen. However, it does not mention measurement fault-tolerant design.

[0010] The 2009 paper "Design of Interface Circuit for High-Reliability Incremental Photoelectric Encoder" in Measurement and Control Technology addresses the poor pulse or jitter interference suppression capability of current incremental photoelectric encoder direction-discriminating counting circuits. It summarizes the normal changes in signal level during forward and reverse rotation, and utilizes a state machine to detect various valid, erroneous, and invalid states of the photoelectric encoder output signal. Through three signals—speed counting pulse, rotation direction, and error alarm—it meets the requirements of high accuracy and high fault tolerance counting. This scheme implements reliability and fault tolerance design for a single output signal; however, this design method still has a single point of failure and does not address multi-redundant output fault tolerance design.

[0011] The 2015 paper "Design of an Aerospace-Grade Dual-Readout Multi-Turn Absolute Optical Encoder" in *Advances in Lasers and Optoelectronics* describes a space-grade multi-turn absolute optical encoder based on a dual-readout system. Its dual-slit and dual-readout system enables cold backup of the signal processing circuitry. While this design provides simple cold backup of test results and can resolve single-point faults, it still requires human intervention and switching within the loop when a fault occurs. In contrast, the four-channel angle measurement data in this method features an automatic fault-tolerant design.

[0012] The 2009 paper "Design of an Aerospace-Grade Absolute Photoelectric Encoder with Dual Readout System" in the Optical Precision Engineering journal designed an aerospace-grade absolute photoelectric encoder with a dual readout system featuring cold backup. While this design provides simple cold backup of test results and can resolve single-point faults, it requires human intervention and switching within the loop when a fault occurs. In contrast, the four-channel angle measurement data in this method features an automatic fault-tolerant design.

[0013] To improve the reliability of absolute photoelectric encoders, incremental measurement processing has been implemented in recent years for the precision code data of these encoders. This helps determine the correctness of the absolute measurement results and provides some tolerance for coarse and medium precision code channels. However, if an anomaly occurs in the precision code channel, neither the absolute nor incremental measurement results will provide accurate and high-precision results. Therefore, the application of this type of encoder in the aerospace field still carries the risk of output anomalies.

[0014] Meanwhile, since the photoelectric encoder contains more than a dozen code track detection channels, if multiple fault modes such as two or more code track failures occur, for example, if foreign objects generated by other connection modules drift into the multiple code tracks of the photoelectric encoder's optical code disk in a vacuum environment, causing errors in both absolute and incremental measurement data when rotating to multiple angles, the judgment switching rules for unidirectional absolute to incremental data output cannot continuously output correct data, and the selection of single absolute data or single incremental data judgment rules also cannot continuously output correct data, resulting in limited fault tolerance of the product. Summary of the Invention

[0015] To address the shortcomings of existing technologies, the purpose of this invention is to provide a high-fault-tolerant design method and system for measuring the measurement results of a spaceborne high-precision photoelectric encoder.

[0016] A high-fault-tolerant design method for measurement results of a spaceborne high-precision photoelectric encoder, provided by the present invention, includes: Step S1: Construct a radial dual-channel light-receiving path; Step S2: Obtain the first absolute angle data, the second absolute angle data, the first incremental angle data, and the second incremental angle data based on the radial receiving and transmitting optical paths dual channels; Step S3: Based on the acquired first-channel absolute angle data, second-channel absolute angle data, first-channel incremental angle data, and second-channel incremental angle data, obtain angle data that meets the preset requirements according to the preset judgment rules.

[0017] Preferably, step S1 includes: configuring two sets of light transmitting and receiving devices at radially symmetrical positions based on an optical code disk to construct two coarse code, medium-precision code, and fine code level channels and two through-loop level channels; and obtaining two coarse code, medium-precision code, and fine code level channels and two through-loop level channels based on the constructed two coarse code, medium-precision code, and fine code level channels and two through-loop level channels.

[0018] Preferably, step S2 includes: comparing the levels of the two coarse codes, intermediate codes, and fine codes with a reference level to obtain the first absolute angle data and the second absolute angle data; The reference level is based on two pass-through levels, which are selected as the reference level according to a preset rule or by an instruction.

[0019] Preferably, the reference level is based on two pass-through levels selected as the reference level according to a preset rule or by an instruction, including: The voltage value of the first pass-through coil is judged. When the voltage value exceeds the threshold, the first pass-through coil level is judged to be invalid, and the second pass-through coil level is switched to obtain the reference level; or the first pass-through coil level or the second pass-through coil level is forcibly selected as the reference level through an instruction.

[0020] Preferably, step S2 includes: obtaining a first incremental angle data and a second incremental angle data by incrementally accumulating the two channels of precision code signal data.

[0021] Preferably, step S3 includes: comparing the first-channel absolute angle data, the second-channel absolute angle data, the first-channel incremental angle data, and the second-channel incremental angle data; the default comparison rule is that when the first-channel absolute angle data and the second-channel absolute angle data are consistent, the absolute angle data is output; when they are inconsistent, the first-channel incremental angle data and the second-channel incremental angle data are compared; if they are consistent, the incremental angle data is output; if they are inconsistent, the default comparison rule or the non-default comparison rule is repeatedly triggered; wherein, the non-default comparison rule is to manually formulate a customized adjustment strategy based on the cause of the fault and output angle data that meets the preset requirements.

[0022] Preferably, the method further includes: when the two absolute angle data are consistent, assigning the absolute angle data to the two incremental angle data to achieve real-time correction when there is an error in the incremental angle data.

[0023] A high-fault-tolerant design system for measuring the measurement results of a spaceborne high-precision photoelectric encoder, provided by the present invention, includes: Module M1: Constructs a radial dual-channel light-receiving and receiving path; Module M2: Based on the radial receiving and transmitting optical path dual channel, it obtains the first channel absolute angle data, the second channel absolute angle data, the first channel incremental angle data, and the second channel incremental angle data; Module M3: Based on the acquired first-channel absolute angle data, second-channel absolute angle data, first-channel incremental angle data, and second-channel incremental angle data, angle data that meets preset requirements is obtained according to preset judgment rules.

[0024] Preferably, the module M1 includes: two sets of light transmitting and receiving devices configured radially symmetrically on an optical code disk to construct two coarse code, medium-precision code, and fine code level channels and two through-loop level channels; and obtaining two coarse code, medium-precision code, and fine code level channels and two through-loop level channels based on the constructed two coarse code, medium-precision code, and fine code level channels and two through-loop level channels respectively. The module M2 includes: after comparing and processing the levels of two coarse codes, medium-precision codes, and precision codes with a reference level, the first absolute angle data and the second absolute angle data are obtained; The first incremental angle data and the second incremental angle data are obtained by incrementally accumulating the two channels of precision code signal data.

[0025] Preferably, module M3 includes: comparing the first channel absolute angle data, the second channel absolute angle data, the first channel incremental angle data, and the second channel incremental angle data; the default comparison rule is that when the first channel absolute angle data and the second channel absolute angle data are consistent, the absolute angle data is output; when they are inconsistent, the first channel incremental angle data and the second channel incremental angle data are compared; if they are consistent, the incremental angle data is output; if they are inconsistent, the default comparison rule or the non-default comparison rule is repeatedly triggered; wherein, the non-default comparison rule is to manually formulate a customized adjustment strategy based on the cause of the fault and output angle data that meets the preset requirements; When the two absolute angle data are consistent, the absolute angle data is assigned to the two incremental angle data to achieve real-time correction when there is an error in the incremental angle data.

[0026] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention adopts a radial receiving and transmitting dual-channel design to realize two channels of absolute angle data, two channels of incremental data, and four channels of measurement data. The angle data is output according to a predetermined judgment rule. The judgment rule can correctly output the angle measurement data based on the specific situation of single-point fault or multiple faults and can be modified accordingly. 2. This invention incorporates comprehensive redundancy backup design and output measurement result auxiliary judgment design for photoelectric encoders. When any single point of failure occurs in the product, it can still output correct high-precision measurement results. It also has high fault tolerance for multiple failures of photoelectric encoders, greatly reducing the failure rate of photoelectric encoders, improving reliability, and providing a guarantee for the safe and stable operation of spaceborne laser communication. Attached Figure Description

[0027] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings: Figure 1 This is a side view diagram of the dual-channel, absolute, and incremental channels of a photoelectric encoder.

[0028] Figure 2 This is a front view of a photoelectric encoder with dual-channel, absolute, and incremental channels.

[0029] Figure 3 This diagram illustrates the selection of the reference comparison level for the photoelectric encoder.

[0030] Figure 4 Flowchart of default judgment rules for measuring angle data.

[0031] Figure 5 Flowchart of default judgment rules for measuring angle data. Detailed Implementation

[0032] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0033] Example 1 The high-fault-tolerant design method for spaceborne high-precision photoelectric encoder measurement results provided by the present invention, such as Figures 1 to 5 As shown, it includes: Step S1: Construct a radial dual-channel light-receiving path; Step S2: Obtain the first absolute angle data, the second absolute angle data, the first incremental angle data, and the second incremental angle data based on the radial receiving and transmitting optical paths dual channels; Step S3: Based on the acquired first-channel absolute angle data, second-channel absolute angle data, first-channel incremental angle data, and second-channel incremental angle data, obtain angle data that meets the preset requirements according to the preset judgment rules.

[0034] Specifically, the radial receiving and receiving dual-channel optical path in step S1 includes two absolute angle data channels and two incremental data channels. Two sets of light transmitting and receiving devices containing through-loop code channels are configured in a radially symmetrical position on an optical code disk to obtain two coarse code, medium-precision code, and fine code level channels as well as two through-loop level channels.

[0035] Specifically, step S2 includes: calculating the first channel absolute angle data and the second channel absolute angle data by comparing and processing the coarse code, intermediate code, and fine code levels with the reference level. The first channel incremental angle data and the second channel incremental angle data are obtained by incrementally accumulating the fine code signal data.

[0036] The reference level is used for comparison processing of each coarse, medium, and fine code channel. The reference level has two sources: a first pass-through level and a second pass-through level. The first and second pass-through levels are obtained from the level values ​​acquired by the receiving and transmitting devices at radially symmetrical positions on the code disk.

[0037] The two pass-through level channels can be selected as the reference level according to preset judgment rules or by instruction, so as to realize cross-backup of the coarse, medium and fine code channels and the pass-through code channel, thereby improving reliability.

[0038] Specifically, the reference level is selected from the first pass-through level and the second pass-through level. The first pass-through level is selected as the reference level by default. When the first pass-through level channel fails, the second pass-through level is switched as the reference level.

[0039] In this embodiment, the voltage value of the first pass-through coil is judged. If it exceeds a threshold, the first pass-through coil level is deemed invalid, and the system automatically switches to the second pass-through coil level. Simultaneously, either the first or second pass-through coil level can be forcibly selected as the reference comparison level via command. The upper and lower thresholds are taken as the maximum voltage level range fluctuating under environmental adaptability conditions of the optical path; specifically, as shown... Figure 3 As shown in Table 1, the comparison results are as follows; Table 1

[0040] Step S3 includes comparing the first-channel absolute angle data, the second-channel absolute angle data, the first-channel incremental angle data, and the second-channel incremental angle data. The default comparison rule is to output the absolute angle data when the first-channel and second-channel absolute angle data are consistent; if they are inconsistent, it is to determine whether the first-channel and second-channel incremental angle data are consistent. If they are consistent, the incremental angle data is output; if they are inconsistent, the default comparison rule or a non-default comparison rule is repeated. The non-default comparison rule is to manually formulate a customized adjustment strategy based on the cause of the fault to output angle data that meets preset requirements.

[0041] The judgment rule is not a one-way switch, that is, the absolute angle data and the incremental angle data can automatically switch the priority output, with the absolute angle data taking priority when the data is relatively consistent.

[0042] The first and second incremental angle data are obtained by incrementally accumulating the precise code signal data. When the two absolute measurement data are consistent, the absolute measurement data is assigned to the two incremental data, realizing real-time correction in case of errors in the incremental data. This assignment function can be either enabled or disabled. Preferred, this assignment function is enabled.

[0043] The comparison and judgment rules can be modified as needed based on the actual photoelectric encoder fault modes. For the four sets of data, only two sets with consistent comparison results are output, or only one set can be selected for output. Under the default comparison and judgment rules, single-point reliability redundancy is achieved for satellite photoelectric encoders. In multiple fault states, the judgment rules are modified by modification to achieve fault tolerance for multiple faults, thus improving product reliability.

[0044] This invention adopts a radial receiving and transmitting dual-channel design to realize two channels of absolute angle data, two channels of incremental data, and four channels of measurement data. The angle data is output according to a predetermined judgment rule. The judgment rule can correctly output the angle measurement data based on the specific situation of single-point fault or multiple faults and can be modified accordingly.

[0045] The present invention also provides a high-fault-tolerant design system for the measurement results of a spaceborne high-precision photoelectric encoder. The high-fault-tolerant design system for the measurement results of a spaceborne high-precision photoelectric encoder can be implemented by executing the process steps of the high-fault-tolerant design method for the measurement results of a spaceborne high-precision photoelectric encoder. That is, those skilled in the art can understand the high-fault-tolerant design method for the measurement results of a spaceborne high-precision photoelectric encoder as a preferred embodiment of the high-fault-tolerant design system for the measurement results of a spaceborne high-precision photoelectric encoder.

[0046] Those skilled in the art will understand that, in addition to implementing the system, apparatus, and their modules provided by this invention in purely computer-readable program code, the same program can be implemented in the form of logic gates, switches, application-specific integrated circuits, programmable logic controllers, and embedded microcontrollers by logically programming the method steps. Therefore, the system, apparatus, and their modules provided by this invention can be considered a hardware component, and the modules included therein for implementing various programs can also be considered structures within the hardware component; alternatively, modules for implementing various functions can be considered both software programs implementing the method and structures within the hardware component.

[0047] Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. Unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.

Claims

1. A high-fault-tolerant design method for measurement results of a spaceborne high-precision photoelectric encoder, characterized in that, include: Step S1: Construct a radial dual-channel light-receiving path; Step S2: Obtain the first absolute angle data, the second absolute angle data, the first incremental angle data, and the second incremental angle data based on the radial receiving and transmitting optical paths dual channels; Step S3: Based on the acquired first-channel absolute angle data, second-channel absolute angle data, first-channel incremental angle data, and second-channel incremental angle data, obtain angle data that meets the preset requirements according to the preset judgment rules.

2. The high-fault-tolerant design method for spaceborne high-precision photoelectric encoder measurement results according to claim 1, characterized in that, Step S1 includes: configuring two sets of light transmitting and receiving devices at radially symmetrical positions based on an optical code disk to construct two coarse code, medium-precision code, and fine code level channels and two through-loop level channels; and obtaining two coarse code, medium-precision code, and fine code level channels and two through-loop level channels based on the constructed two coarse code, medium-precision code, and fine code level channels and two through-loop level channels.

3. The high-fault-tolerant design method for spaceborne high-precision photoelectric encoder measurement results according to claim 1, characterized in that, Step S2 includes: comparing the levels of the two coarse codes, intermediate codes, and fine codes with the reference level to obtain the first absolute angle data and the second absolute angle data. The reference level is based on two pass-through levels, which are selected as the reference level according to a preset rule or by an instruction.

4. The high-fault-tolerant design method for spaceborne high-precision photoelectric encoder measurement results according to claim 3, characterized in that, The reference level is based on two pass-through levels, selected as the reference level according to a preset rule or by instruction, including: The voltage value of the first pass-through coil is judged. When the voltage value exceeds the threshold, the first pass-through coil level is judged to be invalid, and the second pass-through coil level is switched to obtain the reference level; or the first pass-through coil level or the second pass-through coil level is forcibly selected as the reference level through an instruction.

5. The high-fault-tolerant design method for spaceborne high-precision photoelectric encoder measurement results according to claim 1, characterized in that, Step S2 includes: obtaining the first incremental angle data and the second incremental angle data by incrementally accumulating the two channels of precision code signal data.

6. The high-fault-tolerant design method for spaceborne high-precision photoelectric encoder measurement results according to claim 1, characterized in that, Step S3 includes: comparing the first channel absolute angle data, the second channel absolute angle data, the first channel incremental angle data, and the second channel incremental angle data; the default comparison rule is that when the first channel absolute angle data and the second channel absolute angle data are consistent, the absolute angle data is output; when they are inconsistent, the first channel incremental angle data and the second channel incremental angle data are compared; if they are consistent, the incremental angle data is output; if they are inconsistent, the default comparison rule or the non-default comparison rule is repeatedly triggered; wherein, the non-default comparison rule is to manually formulate a customized adjustment strategy based on the cause of the fault and output angle data that meets the preset requirements.

7. The high-fault-tolerant design method for measurement results of a spaceborne high-precision photoelectric encoder according to claim 1, characterized in that, The method further includes: when the two absolute angle data are consistent, assigning the absolute angle data to the two incremental angle data to achieve real-time correction when there is an error in the incremental angle data.

8. A high-fault-tolerant design system for measuring the measurement results of a spaceborne high-precision photoelectric encoder, characterized in that, include: Module M1: Constructs a radial dual-channel light-receiving and receiving path; Module M2: Based on the radial receiving and transmitting optical path dual channel, it obtains the first channel absolute angle data, the second channel absolute angle data, the first channel incremental angle data, and the second channel incremental angle data; Module M3: Based on the acquired first-channel absolute angle data, second-channel absolute angle data, first-channel incremental angle data, and second-channel incremental angle data, angle data that meets preset requirements is obtained according to preset judgment rules.

9. The high-fault-tolerant design system for spaceborne high-precision photoelectric encoder measurement results according to claim 8, characterized in that, The module M1 includes: two sets of light transmitting and receiving devices configured radially symmetrically on an optical code disk to construct two coarse code, medium-precision code, and fine code level channels and two through-loop level channels; and to obtain two coarse code, medium-precision code, and fine code level channels and two through-loop level channels based on the constructed two coarse code, medium-precision code, and fine code level channels and two through-loop level channels respectively. The module M2 includes: after comparing and processing the levels of two coarse codes, medium-precision codes, and precision codes with a reference level, the first absolute angle data and the second absolute angle data are obtained; The first incremental angle data and the second incremental angle data are obtained by incrementally accumulating the two channels of precision code signal data.

10. The high-fault-tolerant design system for spaceborne high-precision photoelectric encoder measurement results according to claim 8, characterized in that, The module M3 includes: comparing the first channel absolute angle data, the second channel absolute angle data, the first channel incremental angle data, and the second channel incremental angle data; the default comparison rule is that when the first channel absolute angle data and the second channel absolute angle data are consistent, the absolute angle data is output; if they are inconsistent, the first channel incremental angle data and the second channel incremental angle data are compared; if they are consistent, the incremental angle data is output; if they are inconsistent, the default comparison rule or the non-default comparison rule is repeatedly triggered; wherein, the non-default comparison rule is to manually formulate a customized adjustment strategy based on the cause of the fault and output angle data that meets the preset requirements; When the two absolute angle data are consistent, the absolute angle data is assigned to the two incremental angle data to achieve real-time correction when there is an error in the incremental angle data.

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