A ground testing device for optical fiber vibration sensor of space camera

Abstract

A ground testing device for fiber optic vibration sensors used in space cameras includes a simulation installation system, a sensing system, and a detection system. The simulation installation system establishes the installation environment, incorporating typical optomechanical structural materials used in space cameras. Its structure is scalable, effectively amplifying strong vibration excitation to meet the required vibration measurement range. The sensing system includes the fiber optic vibration sensor under test and a calibrated standard high-precision electromagnetic vibration sensor. The surface of the fiber optic vibration sensor under test utilizes optical detection mirror characteristics, and a special installation layout allows for the assessment of sensor measurement accuracy and failure magnitude, as well as comparison of connection strength between the fiber optic vibration sensor and different materials and connection processes. The detection system measures whether each fiber optic vibration sensor has become disconnected or completely failed. This invention has a simple structure, is easy to install, and is suitable for testing fiber optic vibration sensors on space cameras.

Description

Technical Field

[0001] This invention belongs to the field of ground testing of sensors and relates to a ground testing device for a fiber optic vibration sensor for a space camera. Background Technology

[0002] As the requirements for lightweight space cameras become increasingly stringent, accurate knowledge of the optomechanical structural mechanical response during the actual launch and orbit insertion phase is crucial to providing effective parameter data for lightweighting and refining the structural design. Currently, ground-based high-vibration electromagnetic sensors each require a cable. Installing vibration sensors at various points on the camera for launch would create challenges for lightweighting and structural design due to cable weight and routing issues. Fiber optic vibration sensors, however, can simultaneously measure dozens of high-vibration points using a single fiber, eliminating the weight and routing difficulties of dozens of cables.

[0003] However, the application of novel fiber optic vibration sensors requires thorough evaluation and testing, including single-unit testing of their measurement mechanical magnitude and accuracy. Furthermore, since space optical cameras typically use over a dozen types of optomechanical materials, and this number continues to increase with the development of advanced materials, and because surface treatment processes and sensor connection processes for each material can alter connection strength, directly impacting the installation and use of fiber optic vibration sensors, ground-based testing of fiber optic vibration sensors for various optomechanical materials used in space cameras is urgently needed. Summary of the Invention

[0004] The technical problem solved by this invention is to overcome the shortcomings of the prior art and provide a ground testing device for fiber optic vibration sensors for space cameras, which solves the problems that the ground strong vibration test of fiber optic vibration sensors is difficult to adapt to various space camera materials and the sufficiency of the testing is insufficient.

[0005] The technical solution of this invention is: a ground testing device for a fiber optic vibration sensor for a space camera, comprising a simulation installation system, a sensing system, and a detection system, wherein:

[0006] Simulated mounting system: used to establish the mounting environment, including one or more mounting structures for vibration amplification made of optical-mechanical structural materials used in space cameras, the mounting structures being placed on a vibration table;

[0007] The sensing system includes a single fiber optic vibration sensor with multiple measurement points and a calibrated standard electromagnetic vibration sensor. Both sensors are mounted on the mounting structure. One fiber optic vibration sensor and one standard electromagnetic vibration sensor constitute a measurement group.

[0008] The detection system corresponds one-to-one with the measurement group and detects the connection strength of the single-fiber multi-point fiber vibration sensor by using the measurement data of the two types of sensors in the measurement group.

[0009] Furthermore, the installation structure is a single-plate configuration, or based on a single-plate configuration, local materials are removed in the thickness and width directions with central symmetry.

[0010] Furthermore, when there are two or more installation structures, each installation structure is distributed along a ring.

[0011] Furthermore, when there are two or more installation structures, the gap D between each installation structure satisfies the following relationship:

[0012]

[0013] In the formula, D is in mm and g. max The maximum acceleration response of the simulated space camera is given in units of 1 gravitational acceleration. f1 is the satellite baseband frequency, f2 is the camera baseband frequency, and M is the safety factor.

[0014] Furthermore, the measurement groups are placed side by side.

[0015] Furthermore, the side-by-side placement and installation layout satisfy the following conditions:

[0016]

[0017] In the formula, g1……g N-1 g N The mechanical response at each installation location is expressed in units of one gravitational acceleration, where g is the standard gravitational acceleration, G is the mechanical response difference (an integer multiple of one gravitational acceleration), and N is the number of measurement groups.

[0018] Furthermore, the fundamental frequency of the mounting structure is greater than 100Hz.

[0019] Furthermore, the surface of the packaging structure of the fiber optic vibration sensor is polished to a surface shape that is more than 1 / 10 of the visible light wavelength.

[0020] Furthermore, the detection system employs a laser interferometer or a theodolite.

[0021] Furthermore, the optical-mechanical structural materials used in the space camera include, but are not limited to, mirror materials, metallic materials, non-metallic materials, and metastructures.

[0022] The advantages of this invention compared to the prior art are:

[0023] (1) This invention uses a ring-shaped simulated installation system, a parallel-arranged sensing system and a detection system to accurately detect the loosening of the sensor connection before and after vibration with only one vibration. It effectively captures the different connection strength changes from loosening to detachment, thereby replacing the traditional method of judging the connection strength change by only vibration response. It can achieve mutual verification of multiple methods.

[0024] (2) Accordingly, the present invention can meet the connection firmness assessment of fiber optic vibration sensors with various typical space camera structural materials and different connection processes with a single vibration, avoiding dozens of vibration tests with a single material and a single process.

[0025] (3) Based on the distribution of vibration magnitude response differences, the present invention can locate the strong vibration magnitude of different materials and different connection processes in the first time if problems such as accuracy deviation failure, loosening and falling off occur. This provides an analytical basis for improvement and changes the traditional problem of relying on adjusting vibration excitation and multiple vibrations of multiple magnitudes. Attached Figure Description

[0026] Figure 1 This is a schematic diagram illustrating the composition principle of the device of the present invention;

[0027] Figure 2 This is a schematic diagram of the single-material simulation assembly structure and sensor installation of the present invention. Detailed Implementation

[0028] This invention takes a fiber optic vibration sensor for a space camera as the implementation object and conducts ground testing on it. For example... Figure 1 As shown, the device of the present invention mainly includes: a simulation assembly system, a sensing system, and a detection system, wherein:

[0029] Simulated mounting system: Used to establish the mounting environment, including a strong vibration amplification structure made of typical optomechanical structural materials used in space cameras, meeting the vibration measurement range. Typical optomechanical structural materials used in space cameras mainly include mirror materials, metallic materials, and non-metallic materials, and can also be expanded to include emerging structural materials such as metastructures. Mirror materials mainly include: fused silica glass, ULE glass, microcrystalline glass, silicon carbide ceramics, and beryllium mirrors. Other metallic materials are not assessed as single-mirror materials because the mirror body is metallic. Composite mirror bodies such as silicon carbide short-fiber mirrors are assessed according to non-metallic material standards. Metallic materials mainly include: aluminum alloys, titanium alloys, Invar steel, and aluminum-based silicon carbide of different volume fractions. Non-metallic materials mainly include: resin-based carbon fiber, ceramic carbon fiber, carbon fiber, and pitch-based carbon fiber.

[0030] The sensing system comprises a single-fiber multi-point fiber optic vibration sensor under test and a calibrated high-precision electromagnetic vibration sensor to verify the performance of the fiber optic vibration sensor. The single-fiber multi-point fiber optic vibration sensor eliminates the inherent inconsistencies of multi-fiber sensors. Both sensors are mounted on a structure made of optomechanical structural materials.

[0031] Testing system: Used to assess the connection strength of fiber optic vibration sensors.

[0032] like Figure 1 As shown, to improve testing efficiency, this invention arranges various materials in a ring. If it is necessary to apply emerging optomechanical structural materials such as metastructures to evaluate the installation performance of fiber optic vibration sensors, the arrangement can be extended along the ring. The entire simulation installation system is built on a vibration table.

[0033] To fully assess the adaptability of fiber optic vibration sensors to camera vibration ranges, the simulated mounting structures using different optomechanical materials must have a fundamental frequency greater than 100Hz. These structures utilize a single-plate (long plate) configuration with identical mode shapes, consistent edge heights to ensure consistent sensor detection height, and uniform mechanical responses at the edge ends. This allows for sufficient amplification of the strong vibration excitation from the ground-based simulated transmission section while maintaining consistent mechanical responses at the edge ends. For ease of testing, the simulated mounting structures for the optomechanical materials are modified by varying the width and thickness of the structural foundation. If necessary, local material dimensions can be removed from both sides (i.e., dimensions a and b, removed symmetrically at the center), ultimately adjusting the structural mechanical responses of different materials. Figure 2 As shown. This allows for a thorough evaluation of the fiber optic vibration sensor's adaptability to the camera's vibration range, while also meeting performance and pose detection requirements.

[0034] To avoid collisions between the edges of two adjacent structures during high-level vibrations, the distance between two adjacent simulated installation structures must meet the following requirements:

[0035]

[0036] In the formula, D is the distance between two adjacent simulated installation structures (from edge to edge, i.e., edge gap), in mm. max To simulate the maximum acceleration response of a space camera, the unit is 1 gravitational acceleration. The minimum frequency of the f1 satellite fundamental frequency and the f2 camera fundamental frequency is used, but other frequency points that cause the maximum response can also be considered. M is a safety factor (to avoid vibration interference and collisions; the safety factor can be greater than 2), leaving a margin for clearance distance.

[0037] When installing the sensing system, spot welders, ultrasonic welders, polymer adhesive bonding devices, and standard electromagnetic vibration sensors should be placed side-by-side at the same height and response position. Figure 2As shown, the combined annular simulated installation structure system using different materials facilitates the horizontal detection of positional changes in each fiber optic vibration sensor. Fiber optic vibration sensors with different connection technologies and standard electromagnetic vibration sensors placed side-by-side are considered a group. The installation layout of each group within a single material simulated installation structure must meet the following requirements:

[0038]

[0039] In the formula, g1……g N-1 g N The mechanical response at each installation location is represented by 1 gravitational acceleration; g is the standard gravitational acceleration; G is the difference in mechanical response, which is an integer multiple of 1 gravitational acceleration. The specific multiple is determined comprehensively based on the single-material simulation structure and sensor size, as well as the required precision of the failure mechanical magnitude.

[0040] The surface of the fiber optic vibration sensor packaging structure needs to be polished to a shape that is more than 1 / 10 of the visible light wavelength to facilitate high-precision detection of the attitude changes of each sensor before and after vibration.

[0041] By adopting a special installation layout, it is possible to determine the measurement accuracy and failure level of the sensor, and to compare the connection strength of the fiber optic vibration sensor with different structural materials and different connection processes.

[0042] The detection system, corresponding to the ring-shaped simulated installation system, is also arranged in a ring-shaped circumferential array, each corresponding to one of the fiber optic vibration sensors to detect attitude changes, such as... Figure 1 As shown. The system measures whether each fiber optic vibration sensor has become disconnected or completely failed. A high-precision laser interferometer is preferred for the detection system; however, a high-precision theodolite can also be considered if the foundation provides vibration isolation.

[0043] Once all the equipment is set up and in place, the performance and mechanical adaptability of the fiber optic vibration sensors in the simulated installation environment of a space camera can be evaluated. During strong vibration, the mechanical response data of each sensor is monitored: the mechanical response is compared with that of a standard high-precision ground electromagnetic sensor to determine if there are any performance deviations; the mechanical responses of different materials and connection processes are compared to determine if there are any relative anomalies and to pinpoint the material, process, and vibration magnitude at which the problem occurs; after vibration, the positional changes of each fiber optic vibration sensor are acquired through the detection system, especially whether sensors with abnormal mechanical responses undergo attitude changes exceeding seconds, thus pinpointing whether the anomaly is due to the connection process or the internal components of the fiber optic vibration sensor's casing. This allows for the evaluation of the functional performance and mechanical adaptability of the fiber optic vibration sensors in the simulated installation environment of a space camera. If anomalies are found, the problem can be quickly identified as either a sensor design issue or a connection process problem, as well as the material, process, and magnitude of the connection process issue, allowing for subsequent improvements and adjustments.

[0044] The contents not described in detail in this specification are common knowledge to those skilled in the art.

Claims

1. A ground testing device for a fiber optic vibration sensor used in a space camera, characterized in that: This includes a simulation installation system, a sensing system, and a detection system, among which: Simulated mounting system: used to establish the mounting environment, including one or more mounting structures for vibration amplification made of optical-mechanical structural materials used in space cameras, the mounting structures being placed on a vibration table; The sensing system includes a single fiber optic vibration sensor with multiple measurement points and a calibrated standard electromagnetic vibration sensor. Both sensors are mounted on the mounting structure. One fiber optic vibration sensor and one standard electromagnetic vibration sensor constitute a measurement group. The detection system corresponds one-to-one with the measurement group and detects the connection strength of the single-fiber multi-point fiber vibration sensor by using the measurement data of the two types of sensors in the measurement group. The installation structure is a single-plate configuration, or a single-plate configuration in which local materials are removed in the thickness and width directions with central symmetry. When there are two or more installation structures, each installation structure is distributed along a ring. The surface of the packaging structure of the fiber optic vibration sensor is polished to a shape that is more than 1 / 10 of the visible light wavelength. The detection system described above uses a laser interferometer or a theodolite; When there are two or more installation structures, the gap distance D between each installation structure satisfies the following relationship: In the formula, D is in mm and g. max The maximum acceleration response of the simulated space camera is given in units of 1 gravitational acceleration. f1 is the satellite baseband frequency, f2 is the camera baseband frequency, and M is the safety factor. The measurement groups are placed side by side; The side-by-side placement and installation layout satisfy the following conditions: In the formula, g1……g N-1 g N The mechanical response at each installation location is expressed in units of one gravitational acceleration, where g is the standard gravitational acceleration, G is the mechanical response difference (an integer multiple of one gravitational acceleration), and N is the number of measurement groups.

2. The ground testing device for a fiber optic vibration sensor for a space camera according to claim 1, characterized in that: The fundamental frequency of the installation structure is greater than 100Hz.

3. The ground testing device for a fiber optic vibration sensor for a space camera according to claim 1, characterized in that: The optical-mechanical structural materials used in the space camera include mirror materials, metallic materials, non-metallic materials, and metastructures.

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