Ion thruster grid assembly temperature and distortion in-situ measurement method and system

Abstract

The application provides a kind of ion thruster grid assembly temperature and deformation synchro measurement method and system, environmental chamber simulates experimental environment, probe leads out the three-dimensional deformation and temperature information of grid, image acquisition system collects the image of probe, through spectroscope, incident light is divided into two beams, respectively receives visible light and infrared light, using the visible light deformation image of probe collected by image acquisition system, then combining infrared light information can obtain the temperature information of corresponding position simultaneously, realize the accurate correspondence of temperature and deformation, and then realize the synchro measurement of temperature and deformation;Through vacuum pumping device, ensure that the vacuum degree of environmental chamber reaches the requirement of real working condition of grid, through the cooperation of annular heater and cooling system, the real thermal radiation is applied to grid, and the simulation experimental environment is simulated;Digital image processing system processes the image recorded by image acquisition system, obtains the three-dimensional deformation information and temperature information of grid, and accurately analyzes the influence of temperature change on grid thermal deformation.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of measurement, more particularly, to a method and system for measuring the temperature and deformation of a grid assembly of an ion thruster. BACKGROUND

[0002] An ion thruster is one of the most widely used and researched electric thrusters, which has the advantages of high specific impulse and wide thrust regulation range, and is mainly applied to the fields of geosynchronous orbit satellite position keeping, all-electric propulsion, deep space exploration main propulsion, and drag-free control. The grid ion thruster mainly uses electrostatic propulsion, the principle of which is to use electric energy to ionize the working substance, and accelerate the positive ions to be sprayed out under the action of the electrostatic field of the grid assembly, thereby generating thrust. The structure of the grid assembly directly determines the performance of the ion thruster, such as thrust and specific impulse. The common grid structure includes three parts of screen grid, acceleration grid, and deceleration grid, which are fixed through a grid mounting ring. During the operation of the ion thruster, the heat radiation and plasma deposition generated by the ionization of the working substance will heat the grid, and the heat flux density of the radiation received by different grids is different due to the shielding between the grids, which will cause the temperature distribution in the grid to be uneven, thereby causing the thermal deformation of the grid to be inconsistent, reducing the grid spacing, and changing the geometric parameters of the grid. In order to ensure the extraction performance of the ion beam, the installation spacing of the grid is generally only 0.5-1mm, leaving little space for thermal deformation. Therefore, the thermal deformation of the grid caused by temperature will cause the performance of the thruster to decrease, and in severe cases, will cause the thruster to shut down and fail. In order to improve the working life of the thruster, it is necessary to understand the thermal deformation law of the grid and make corresponding design of the grid structure, so the measurement of the temperature and grid spacing of the ion thruster grid is very important.

[0003] Currently, the measurement of grid temperature and grid spacing mainly includes two aspects: measurement method and measurement system. In terms of measurement method, for the measurement of grid temperature, it is divided into contact and non-contact. The existing technology (Yuan J, Liang D, Zhou S, et al. Development of thermal spacing measurement system for ion thruster grid assembly[J]. Journal of National University of Defense Technology, 2020, 42(1): 51-58.) and (MacRae G S, Zavesky R J, Gooder S T. Structural and thermal response of 30 cm diameter ion thruster optics[C] / / Proceedings of 25th Joint Propulsion Conference, 1989) measure the temperature of part of the position on the grid surface by pasting temperature sensors. Although the contact measurement method has high accuracy, it measures the temperature value of part of the position by pasting temperature sensors. This measurement method has low spatial resolution and cannot obtain the overall temperature distribution of the grid surface. Moreover, it cannot be measured under beam conditions. The non-contact infrared thermal imager field measurement method can solve the above two problems, but due to the shielding between multiple layers of grids, the temperature of the inner layer of the shielded grid cannot be measured. Currently, it is still not available. For the measurement of grid deformation, it is also divided into contact and non-contact. For contact measurement (MacRae G S, Zavesky R J, Gooder S T. Structural and thermal response of 30 cm diameter ion thruster optics[C] / / Proceedings of 25th Joint Propulsion Conference, 1989), sensors are installed on the grid surface for direct measurement. The contact measurement method can only obtain two-dimensional deformation information of part of the grid position, and has low spatial resolution. Moreover, this measurement method will have a certain impact on the thermal deformation of the grid itself (such as the shape and material of the contact measurement probe will directly affect the measurement accuracy, any mechanical vibration during contact measurement may cause the probe to vibrate and affect the measurement results, long-term contact measurement may cause the measured object to deform slightly, which may interfere with the measurement results), and cannot be measured under beam conditions. Non-contact measurement is an indirect measurement. (Yuan J, Liang D, Zhou S, et al. Development of thermal spacing measurement system for ion thruster grid assembly[J]. Journal of National University of Defense Technology, 2020, 42(1): 51-58.) pastes cooperation marks at different grid centers, heats the grid to cause deformation, and uses a high-resolution digital camera to record the deformation process. Finally, the thermal deformation of the grid is indirectly measured by analyzing the displacement of the cooperation marks in the image; this measurement method is optical camera measurement.Currently, the non-contact measurement method is mainly applied to the measurement of two-dimensional deformation of the position of the grid part, and the obtained grid deformation information is limited. More importantly, the current measurement of the grid temperature and deformation needs to obtain the overall temperature distribution and deformation information of the grid surface at the same time, and the temperature change and thermal deformation change of each point of the grid need to be corresponded in time and space, so that the influence of the temperature change of the grid on the thermal deformation can be more accurately obtained, and the structure of the grid can be designed accordingly to improve the working performance and service life of the grid. However, the current measurement of the grid temperature and deformation is a separate measurement, and cannot be measured in the same field, so the corresponding relationship between the grid temperature and deformation cannot be accurately obtained, and the influence of the temperature on the grid deformation cannot be accurately judged.

[0004] At present, there are mainly two kinds of measurement systems, one is to use a heating device to heat the grid in an atmospheric environment to simulate the deformation of the grid for measurement, and the other is to place the ion thruster in a vacuum chamber in a vacuum environment, and start the grid ion thruster to measure the deformation of the grid. For the measurement system of the grid deformation experiment, when the measurement is carried out in the atmospheric environment, heat is generated by the heating device to simulate the temperature field of the grid in the working process of the ion thruster, but the vacuum environment in the working process of the thruster is not considered. This will cause the grid to be oxidized in the atmospheric environment, and the experimental conditions are quite different from the real working conditions of the ion thruster, it is difficult to simulate the real working conditions of the thruster, and the accuracy of the measurement result is affected; when the measurement experiment is carried out in the vacuum chamber, in the vacuum system, the thruster needs to be placed in the real vacuum chamber, and there is an ion beam in the vacuum chamber. When the non-contact measurement of the grid deformation is carried out by using a camera, tin foil paper needs to be wrapped around the experimental equipment (such as a high-precision positioning platform and a long-distance microscope) to prevent ion sputtering, and the experimental process is complex. On the other hand, in the vacuum chamber, the temperature of the grid cannot be directly measured by using a temperature sensor due to the existence of the beam, and the temperature information of the grid cannot be obtained, which affects the experimental effect. In summary, the current grid temperature and deformation measurement system is still not perfect, and the measurement result cannot reflect the real thermal deformation behavior of the grid, and the design of the grid structure cannot play a good supporting role, and even may cause design risks.

[0005] Therefore, it is urgent to provide an ion thruster grid assembly temperature and deformation simultaneous measurement method and system which can realize temperature and deformation simultaneous measurement and the measurement result is more in line with the actual situation. SUMMARY

[0006] Therefore, the present application provides an ion thruster grid assembly temperature and deformation simultaneous measurement system, which comprises:

[0007] an environmental box;

[0008] The annular heater is fixedly connected with the inner wall of the environmental box through a fixing rod;

[0009] The grid is arranged in the environmental box, and the center of the grid is arranged opposite to the center of the annular heater in the left-right direction.

[0010] The probe comprises a rear end and a front end arranged opposite in the left-right direction, the front end is spherical, a mark point is arranged on a surface of the front end away from the center of the grid in the left-right direction, and the rear end is bonded with the surface of the grid.

[0011] An observation window is arranged on the box body of the environmental box opposite to the grid in the left-right direction.

[0012] The image acquisition system comprises a beamsplitter, a high-resolution camera group and an infrared thermal imager, the beamsplitter is arranged opposite to the observation window in the left-right direction, and the infrared thermal imager is arranged at one end of the beamsplitter away from the observation window; in the front-back direction, the high-resolution camera group comprises high-resolution cameras arranged opposite on both sides of the beamsplitter, and the front-back direction is perpendicular to the left-right direction.

[0013] The digital image processing system comprises an image processing software, and the digital image processing system is in communication connection with the image acquisition system.

[0014] In another aspect, the application provides a method for measuring the temperature and deformation of a grid assembly of an ion thruster in a same field, which is applied to the system for measuring the temperature and deformation of the grid assembly of the ion thruster in a same field and comprises the following steps:

[0015] A vacuumizing device connected with the environmental box is turned on to adjust the vacuum degree in the environmental box.

[0016] A cooling system arranged on the inner wall of the grid and the environmental box is turned on.

[0017] The annular heater is turned on.

[0018] The image acquisition system photographs the probe and records the photographing result.

[0019] The annular heater is turned off.

[0020] The image acquisition system photographs the probe and records the photographing result.

[0021] The cooling system and the vacuumizing device are turned off, and the image acquisition system stops photographing.

[0022] The digital image processing system processes the photographing result of the image acquisition system.

[0023] Compared with the prior art, the method and system for measuring the temperature and deformation of the grid assembly of the ion thruster in a same field provided by the application at least achieve the following beneficial effects:

[0024] The ion thruster grid assembly temperature and deformation simultaneous field measurement system provided by the application comprises an environment box, a ring heater is arranged in the environment box to simulate heat generated in the working process of the thruster, the center of the grid is opposite to the center of the ring heater to simulate the real working condition of the ion thruster as much as possible, a probe is introduced as an information carrier, the probe is bonded with the surface of the grid to facilitate observation and capture of the temperature and three-dimensional deformation information of the grid, an observation window is arranged on the environment box, an infrared thermal imager and a high-resolution camera group are designed to simultaneously shoot the thermal image and visible light image of the probe in one signal triggering through a designed beam splitter, the corresponding time of collection is realized, the temperature information of the grid is measured by the infrared thermal imager, the three-dimensional deformation information of the grid is measured by the high-resolution camera group by using the binocular vision ranging principle, then the corresponding of the infrared image and the visible light image is realized according to the probes bonded at different positions, the corresponding of the two images in space is completed, and finally the simultaneous field measurement of the temperature and deformation is realized.

[0025] Of course, it is not necessary for any product embodying the present application to achieve all of the above-listed technical effects simultaneously.

[0026] Other features of the present application, and their advantages, will become apparent in the non-limiting examples of the application described below with reference to the drawings. BRIEF DESCRIPTION OF DRAWINGS

[0027] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the application and, together with the description, serve to explain the principles of the application.

[0028] Figure 1 is a schematic view of an ion thruster grid assembly temperature and deformation simultaneous field measurement system provided by the application;

[0029] Figure 2 is a schematic view of an image acquisition system and a grid in an ion thruster grid assembly temperature and deformation simultaneous field measurement system provided by the application;

[0030] Figure 3 is a schematic view of another image acquisition system and a grid

[0031] Figure 4 is a structural diagram of a probe;

[0032] Figure 5 is a structural diagram of a probe and a grid bonding structure;

[0033] Figure 6 is a structural diagram of a circulating water tank;

[0034] Figure 7 is a structural diagram of a cooling pipe and a grid;

[0035] Figure 8 is a structural diagram of a temperature detection device;

[0036] Figure 9 is a flow chart of a temperature and deformation field measurement method of a grid assembly of an ion thruster provided by the present application;

[0037] Figure 10 is a flow chart of another temperature and deformation field measurement method of a grid assembly of an ion thruster provided by the present application;

[0038] Figure 11 is a flow chart of an experimental calibration process;

[0039] 100-experimental table, 1-environment box, 2-circular heater, 3-fixing rod, 4-grid, 41-screen grid, 42-accelerating grid, 5-probe, 51-rear end, 52-front end, 521-marking point, 6-image acquisition system, 61-dichroic mirror, 611-bisplitting dichroic mirror, 612-triplet, 62-high-resolution camera, 63-infrared thermal imager, 64-lens, 7-observation window, 8-first probe, 9-second probe, 10-circulating water tank, 101-water inlet pipe, 102-water outlet pipe, 14-cooling pipe, 141-water inlet, 142-water outlet, 15-screen grid probe ring group, 16-accelerating grid probe ring group, 17-temperature detection device, 171-thermocouple, 1711-grid thermocouple, 1712-probe thermocouple, 172-data logger, 18-vacuum pumping device, left-right direction-x, front-back direction-y. DETAILED DESCRIPTION

[0040] Various exemplary embodiments of the present application will now be described in detail with reference to the accompanying drawings. It should be noted that the relative arrangement of the components and steps set forth in the embodiments, numerical expressions, and numerical values are not limiting to the scope of the present application unless otherwise specifically stated.

[0041] The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way limiting to the scope of the application or its applications or uses.

[0042] Techniques, methods, and apparatus known to those of ordinary skill in the relevant art(s) can not be discussed in detail herein. However, where appropriate, the techniques, methods, and apparatus should be considered as being part of the description of the application.

[0043] In all of the examples shown and discussed herein, any specific values should be interpreted as merely exemplary and not limiting. Thus, other examples of the exemplary embodiments can have different values.

[0044] It should be noted that like reference numerals and letters refer to like items throughout the drawings, and once an item is defined in one drawing, it is not necessary to discuss it further in subsequent drawings.

[0045] Embodiment 1

[0046] With reference to Figures 1 to 8 The present application provides an ion thruster grid assembly temperature and deformation field measurement system, comprising:

[0047] An environmental box 1;

[0048] An annular heater 2 is fixedly connected to the inner wall of the environmental box 1 through a fixing rod 3;

[0049] A grid 4 is arranged in the environmental box 1, and the center of the grid 4 is arranged opposite to the center of the annular heater 2 along a left-right direction x;

[0050] A probe 5 includes a rear end 51 and a front end 52 arranged opposite along the left-right direction x, the front end 52 is spherical, a mark point 521 is arranged on the surface of the front end 52 away from the center of the grid 4 along the left-right direction x, and the rear end 51 is bonded to the surface of the grid 4;

[0051] An observation window 7 is arranged on the box body of the environmental box 1 opposite to the grid 4 along the left-right direction x;

[0052] An image acquisition system 6 includes a beam splitter 61, a high-resolution camera group, and an infrared thermal imager 63, the beam splitter 61 is arranged opposite to the observation window 7 along the left-right direction x, and the infrared thermal imager 63 is arranged at the end of the beam splitter 61 away from the observation window 7; along an front-back direction y, the high-resolution camera group includes high-resolution cameras 62 arranged opposite on both sides of the beam splitter 61, and the front-back direction y is perpendicular to the left-right direction x;

[0053] A digital image processing system (not shown in the figure) includes image processing software, and the digital image processing system is communicatively connected to the image acquisition system 6.

[0054] Specifically, the environmental box 1 is placed on the experimental table 100, the environmental box 1 is made of stainless steel material, the size is determined according to the size of the grid electrode 4, and the environmental box 1 is only exemplarily described as 60cm*60cm*60cm in size in the application; the annular heater 2 is fixedly connected with the inner wall of the environmental box 1 through the fixing rod 3, and provides a certain basis for realizing the simulation heating environment later; the grid electrode 4 is arranged in the environmental box 1, the center of the grid electrode 4 and the center of the annular heater 2 are oppositely arranged along the left-right direction x; the centering of the center of the grid electrode 4 and the center of the annular heater 2 is ensured, the centering means that the center of the grid electrode 4 and the center of the annular heater 2 are on the same straight line, and the real working condition of the ion thruster is simulated as much as possible; the probe 5 includes the rear end 51 and the front end 52 oppositely arranged along the left-right direction x, the front end 52 is spherical, the center of the rear end is provided with a mark point 521, and the rear end 51 is bonded with the surface of the grid electrode 4; the rear end 51 is bonded with the surface of the grid electrode 4, so that the probe 5 is convenient to replace in the experimental process, and the accuracy of the experimental results is ensured, the center position of the front end 52 is provided with a mark point 521, so that the deformed image of the front end 52 can be more clearly shot in the image acquisition system 6 in the subsequent measurement process; the probe 5 serves as an information carrier, and thermal conduction occurs between the probe 5 and the heated grid electrode 4, thereby providing a certain basis for measuring deformation and temperature; the observation window 7 is arranged on the box body of the environmental box 1 oppositely arranged with the grid electrode 4 along the left-right direction x; the observation window 7 is arranged on one hand to ensure the sealing property of the environmental box 1, and on the other hand to provide a certain position basis for subsequent measurement;

[0055] The image acquisition system 6 includes a beam splitter 61, a high-resolution camera group and an infrared thermal imager 63, the beam splitter 61 is oppositely arranged with the observation window 7 along the left-right direction x, and the infrared thermal imager 63 is arranged at the end of the beam splitter 61 away from the observation window 7; along the front-rear direction y, the high-resolution camera group includes high-resolution cameras 62 oppositely arranged on both sides of the beam splitter 61, and the front-rear direction y is perpendicular to the left-right direction x; through the arrangement of the beam splitter 61, the image of the grid electrode 4 observed through the observation window 7 in the measurement process can be successfully captured by the high-resolution cameras 62 and the infrared thermal imager 63 at the same time; the infrared thermal imager 63 can directly shoot the thermal image of the front end 52 of the probe 5, along the front-rear direction y, the high-resolution cameras 62 oppositely arranged at both ends of the beam splitter 61 shoot the deformed images of the front ends 52 on both sides, thereby providing a certain basis for realizing the same-field measurement of temperature and deformation;

[0056] The digital image processing system includes image processing software, and is in communication connection with the image acquisition system 6. The digital image processing system can analyze the shooting results recorded in the measurement process. The visible light images of the probes taken by the high-resolution camera group are used to calculate the two-dimensional coordinates of each probe 5 distributed on the grid 4 from the edge to the center and further obtain the three-dimensional spatial coordinate values, thereby obtaining the three-dimensional spatial coordinate changes of the probes 5, and accurately measuring the deformation information of the grid 4. The obtained deformation information can be combined with the temperature values obtained from the thermal images measured by the infrared thermal imager 63, and the relationship between the temperature and the deformation can be further analyzed.

[0057] It should be noted that the grid 4 is a multi-layer spherical structure, so the probe 5 at the center position of the grid 4 is vertically pasted on the surface of the grid 4 (the axis of the probe 5 at this position coincides with the center axis of the grid 4), and the probes 5 pasted at other positions of the grid 4 are parallel to the probe 5 at the center axis of the grid 4.

[0058] For the probe 5 pasted on the surface of the grid 4, after the image acquisition system 6 takes the image, the main processing of the image is to process the front end 52 (the spherical part) of the probe 5, because the imaging of the spherical region is approximately circular in the two-dimensional plane when taken at various angles, which is convenient for subsequent process of obtaining three-dimensional coordinates according to two-dimensional coordinates of the probe (i.e. the mark point 521 representing the probe 5 in the visible light image).

[0059] It should be noted that the image acquisition system 6 is a one-piece structure, including a beam splitter 61, an infrared thermal imager 63 and a high-resolution camera group; wherein the beam splitter 61 includes a two-split beam splitter 611 and a three-prism 612, the two-split beam splitter 611 can divide the incident light into two beams of visible light receiving and infrared waveband light receiving, and the visible light is divided into two beams after passing through the three-prism 612; for the size of the adopted beam splitter 61, the imaging size of the high-resolution camera 62, the size of the lens, the focal length and other information are determined. In the embodiment, the object distance, i.e. the distance between the lens 64 and the grid 4, is between 30cm and 35cm, and the distance between the lens 64 and the observation window is between 0cm and 5cm. The following takes the object distance = 30cm as an example for description: i.e. u = 300mm, the imaging target surface size of the high-resolution camera 62 is l = 30mm, the selected lens 64 focal length is f = 50mm, along the left and right direction x, the center distance of the lens 64 from one side of the two-split beam splitter 611 is X, taking the selected three-prism as an angle α = 60°, the distance x1 between the side of the two-split beam splitter 611 close to the lens and the center is 7.5mm, along the front and back direction y, the vertical distance x2 between the center of the two-split beam splitter 611 and the side of the three-prism 612 close to the two-split beam splitter 611 is 7.5mm, and the distance x3 between the center of the side of the three-prism 612 close to the two-split beam splitter 611 and the imaging target surface of the high-resolution camera 62 is approximately 20mm. The distance v = x + x1 + x2 + x3 is obtained according to the camera imaging relationship The value of X can be obtained, and in the experimental process, the clear imaging of the measured object on the phase plane can also be realized by adjusting the focal length. For the specific parameters encountered in the formal implementation process, such as object distance, focal length, etc., the corresponding beam splitter can be designed according to this method.

[0060] It should be noted that the optical glass material used in the beam splitter 61 requires good transmittance for visible light (such as ordinary quartz glass); optical thin film can be coated on the three-prism 612 or a filter is added at the front end of the three-prism 612 to achieve the filtering of infrared light and weaken the interference of infrared light on visible light. The filter can be a blue glass filter, or a blue light source can be set between the lens 64 and the observation window, and then a narrow-band filter is placed in front of 612 to filter out light of other wavebands, so as to weaken the interference of light of other wavebands and improve the accuracy of deformation measurement.

[0061] It should be noted that the high-resolution camera 62 can use a general industrial camera, and the purpose is to realize more convenient trigger control in the image acquisition process; in the embodiment, the ME2P-2621-15U3M camera of the second generation Pro series of Daheng is selected; the infrared thermal imager 63 requires: the temperature measurement can be realized, the temperature measurement range is 0-500℃ (wavelength is 8-14um), the temperature measurement accuracy is: ±1.5℃ (0-100℃) or ±2% (<0 and >100℃), and the refrigeration type infrared thermal imager is selected according to the requirement.

[0062] It should be noted that the heating element in the annular heater 2 is wound by a high-resistance alloy wire, and the front surface of the annular heater 2 is arranged opposite to the spherical surface of the grid 4 along the left-right direction x, so that the heating effect of the annular heater 2 on the grid 4 is improved.

[0063] It should be noted that the probe 5 is generally selected from a material with a small thermal deformation coefficient such as ceramic, because the probe 5 pasted on the surface of the grid 4 may be affected by the temperature during the heating process of the grid 4, so a material which does not deform or deforms little in this temperature range and does not affect the deformation measurement of the grid 4 is selected as much as possible.

[0064] It can be understood that the ion thruster grid 4 temperature and deformation simultaneous field measurement system and method provided by the application comprises an environment box 1, the annular heater 2 is arranged in the environment box 1 to simulate the heat generated in the working process of the thruster, the center of the grid 4 is opposite to the center of the annular heater 2, and the real working condition of the ion thruster is simulated as much as possible; the probe 5 is introduced as an information carrier, which is bonded with the surface of the grid 4, so as to facilitate the observation and capture of the temperature and deformation information of the grid 4; the environment box 1 is provided with an observation window 7, so that the infrared thermal imager 63 and the high-resolution camera group pass through the beam splitter 61 to shoot the probe 5 at the same time, the temperature information of the grid 4 is measured by using the infrared thermal imager 63, the deformation information of the grid 4 is measured by using the binocular vision ranging principle of the high-resolution camera 62, the infrared image and the visible light image are shot at the same time, the simultaneous field measurement of the temperature and the deformation is realized, the visible light image and the thermal image obtained are processed by the digital image processing system, so as to obtain the three-dimensional deformation information and the temperature information of the grid 4, finally the thermal deformation and the temperature change rule of the grid 4 are summarized, the influence of the temperature on the thermal deformation of the grid 4 is analyzed, and the corresponding structure modification and design of the grid 4 can be made according to the measured information.

[0065] Embodiment 2

[0066] The following Figures 1 to 8 will be described to illustrate a specific embodiment of the ion thruster grid 4 temperature and deformation simultaneous field measurement system provided by the application, and the embodiment will be described in detail on the basis of the bonding mode of the grid 4 and the probe 5 in embodiment 1.

[0067] The grid 4 comprises a screen grid 41 and an accelerating grid 42, referring to Figure 1 , the screen grid 41 and the accelerating grid 42 are overlapped along the left-right direction x; referring to Figure 4 , the probe 5 comprises a screen grid probe 8 and an accelerating grid probe 9; a plurality of screen grid probes 8 are adhered to the screen grid 41 to form a screen grid probe annular group 15, and a plurality of accelerating grid probes 9 are adhered to the accelerating grid 42 to form an accelerating grid probe annular group 16; along the front-back direction y, the first annular group and the second annular group are alternately arranged on the grid 4.

[0068] It should be noted that, referring to Figure 1 , the screen grid 41 and the accelerating grid 42 are in a stacked structure along the left-right direction x, and there is an obstruction between the screen grid 41 and the accelerating grid 42, so a plurality of screen grid probes 8 are adhered to the screen grid 41 to form a screen grid probe annular group 15, and a plurality of accelerating grid probes 9 are adhered to the accelerating grid 42 to form an accelerating grid probe annular group 16; along the front-back direction y, the screen grid probe annular group 15 and the accelerating grid probe annular group 16 are alternately arranged on the grid 4, and the adhering layout of the screen grid probe annular group 15 and the accelerating grid probe annular group 16 on the grid 4 can reflect the deformation amount of each layer of the grid 4 along the radial direction from the center of the grid 4 to the edge as much as possible during the measurement, thereby providing a certain structural basis for obtaining three-dimensional deformation information of the grid 4.

[0069] Embodiment 3

[0070] The following Figures 1 to 6 will illustrate a specific embodiment of the ion thruster grid 4 temperature and deformation field measurement system provided by the present application, comprising

[0071] Referring to Figures 1 to 8 , the present application provides an ion thruster grid assembly temperature and deformation field measurement system, comprising:

[0072] An environmental box 1;

[0073] A ring-shaped heater 2, the ring-shaped heater 2 is fixedly connected to the inner wall of the environmental box 1 through a fixing rod 3;

[0074] A grid 4, the grid 4 is arranged in the environmental box 1, and the center of the grid 4 and the center of the ring-shaped heater 2 are oppositely arranged along the left-right direction x;

[0075] A probe 5, the probe 5 comprises a rear end 51 and a front end 52 oppositely arranged along the left-right direction x, the front end 52 is spherical, a mark point 521 is arranged on the surface of the front end 52 away from the center of the grid 4 along the left-right direction x, and the rear end 51 is adhered to the surface of the grid 4;

[0076] An observation window 7 is arranged on the box body of the environmental box 1 opposite to the grid 4 along the left-right direction x;

[0077] An image acquisition system 6, the image acquisition system 6 includes a beam splitter 61, a high-resolution camera group and an infrared thermal imager 63, the beam splitter 61 is opposite to the observation window 7 along the left-right direction x, the infrared thermal imager 63 is arranged at the end of the beam splitter 61 away from the observation window 7; along the front-back direction y, the high-resolution camera group includes high-resolution cameras 62 arranged opposite to both sides of the beam splitter 61, and the front-back direction y is perpendicular to the left-right direction x;

[0078] A digital image processing system (not shown in the figure), the digital image processing system includes image processing software, and the digital image processing system is in communication connection with the image acquisition system 6.

[0079] Specifically, the environmental box 1 is placed on the experimental table 100, the environmental box 1 is made of stainless steel material, the size is determined according to the size of the grid electrode 4, and the environmental box 1 is only exemplarily described as 60cm*60cm*60cm in size in the present application; The annular heater 2 is fixedly connected with the inner wall of the environmental box 1 through the fixing rod 3, and provides a certain basis for realizing the simulation heating environment later; The grid electrode 4 is arranged in the environmental box 1, the center of the grid electrode 4 and the center of the annular heater 2 are opposite to each other along the left-right direction x; The centering of the center of the grid electrode 4 and the center of the annular heater 2 is guaranteed, the centering means that the center of the grid electrode 4 and the center of the annular heater 2 are on the same straight line, and the real working condition of the ion thruster is simulated as much as possible; The probe 5 includes a rear end 51 and a front end 52 opposite to each other along the left-right direction x, the front end 52 is spherical, a mark point 521 is arranged at the center of the rear end, and the rear end 51 is bonded with the surface of the grid electrode 4; The rear end 51 is bonded with the surface of the grid electrode 4, so that the probe 5 can be replaced during the experiment, and the accuracy of the experimental results is guaranteed, the center of the front end 52 is provided with a mark point 521, so that the deformed image of the front end 52 can be clearly photographed by the image acquisition system 6 during the subsequent measurement process; The probe 5 serves as an information carrier, and heat conduction occurs between the probe 5 and the heated grid electrode 4, thereby providing a basis for measuring deformation and temperature; The observation window 7 is arranged on the box body of the environmental box 1 opposite to the grid electrode 4 along the left-right direction x; The observation window 7 is arranged to ensure the sealing of the environmental box 1, and to provide a position basis for subsequent measurement;

[0080] The image acquisition system 6 includes a beamsplitter 61, a high-resolution camera group, and an infrared thermal imager 63. The beamsplitter 61 is arranged opposite to the observation window 7 along the left-right direction x, and the infrared thermal imager 63 is arranged at the end of the beamsplitter 61 away from the observation window 7. Along the front-back direction y, the high-resolution camera group includes high-resolution cameras 62 arranged opposite to each other at both ends of the beamsplitter 61, and the front-back direction y is perpendicular to the left-right direction x. Through the arrangement of the beamsplitter 61, the image of the grid 4 during the measurement process that can be observed through the observation window 7 can be successfully captured by the high-resolution cameras 62 and the infrared thermal imager 63 at the same time. The infrared thermal imager 63 can directly capture the thermal image of the front end 52 of the probe 5. Along the front-back direction y, the high-resolution cameras 62 arranged opposite to each other at both ends of the beamsplitter 61 capture the deformation images of the front ends 52 on both sides, thereby providing a basis for realizing the same-field measurement of temperature and deformation.

[0081] The digital image processing system includes image processing software, is in communication connection with the image acquisition system 6, can analyze the shooting results recorded during the measurement process, calculates the two-dimensional coordinates of each probe 5 distributed on the grid 4 from the edge to the center and further obtains the three-dimensional spatial coordinate values through the visible light images of the probes captured by the high-resolution camera group, thereby obtaining the three-dimensional spatial coordinate changes of the probes 5, accurately measuring the deformation information of the grid 4, combining the temperature values obtained from the thermal images measured by the infrared thermal imager 63, and further analyzing to obtain the relationship between temperature and deformation.

[0082] It should be noted that the grid 4 is a multi-layer spherical structure, so the probe 5 at the center position of the grid 4 is vertically pasted to the surface of the grid 4 (the axis of the probe 5 at this position coincides with the central axis of the grid 4), and the probes 5 pasted at other positions of the grid 4 remain parallel to the probe 5 at the central axis of the grid 4.

[0083] For the probe 5 pasted on the surface of the grid 4, after the image acquisition system 6 captures the image, the processing of the image mainly processes the front end 52 (the spherical part) of the probe 5, because the imaging of the spherical region is approximately circular in the two-dimensional plane when captured at various angles, which facilitates the subsequent process of obtaining the three-dimensional coordinates according to the two-dimensional coordinates of the probe (i.e., the mark point 521 representing the probe 5 in the visible light image).

[0084] It should be noted that the image acquisition system 6 is a one-piece structure, including a beam splitter 61, an infrared thermal imager 63 and a high-resolution camera group; wherein the beam splitter 61 includes a two-split beam splitter 611 and a three-prism 612, the two-split beam splitter 611 can divide the incident light into two beams of visible light receiving and infrared waveband light receiving, and the visible light is divided into two beams after passing through the three-prism 612; for the size of the adopted beam splitter 61, the imaging size of the high-resolution camera 62, the size of the lens, the focal length and other information are determined. In the embodiment, the object distance, i.e. the distance between the lens 64 and the grid 4, is between 30cm and 35cm, and the distance between the lens 64 and the observation window is between 0cm and 5cm. The following takes the object distance = 30cm as an example for description: i.e. u = 300mm, the imaging target surface size of the high-resolution camera 62 is l = 30mm, the selected lens 64 focal length is f = 50mm, along the left and right direction x, the center distance of the lens 64 from one side of the two-split beam splitter 611 is X, taking the selected three-prism as an angle a = 60°, the distance x1 between the side of the two-split beam splitter 611 close to the lens and the center is 7.5mm, along the front and back direction y, the vertical distance x2 between the center of the two-split beam splitter 611 and the side of the three-prism 612 close to the two-split beam splitter 611 is 7.5mm, the distance x3 between the center of the side of the three-prism 612 close to the two-split beam splitter 611 and the imaging target surface of the high-resolution camera 62 is approximately 20mm, the distance v = x + x1 + x2 + x3, according to the camera imaging relationship 1 / f = 1 / u + 1 / v, the value of X can be obtained, and in the experimental process, the clear imaging of the measured object on the surface can also be realized by adjusting the focal length. For the specific parameters encountered in the formal implementation process, such as object distance, focal length, etc., the corresponding beam splitter 61 can be designed according to this method.

[0085] It should be noted that the optical glass material used in the beam splitter 61 requires good transmittance for visible light (such as ordinary quartz glass); optical thin film can be coated on the three-prism 612 or a filter can be added at the front end of the three-prism 612 to achieve the filtering of infrared light and reduce the interference of infrared light on visible light; the filter can be a blue glass filter or a blue light source can be set between the lens 64 and the observation window 7, and then a narrow-band filter is placed in front of 612 to filter out light of other wavebands, so that more visible light information is obtained and the accuracy of deformation measurement is improved.

[0086] It should be noted that the high-resolution camera 62 can use a general industrial camera, the purpose is to achieve more convenient trigger control in the image acquisition process; in the embodiment, the ME2P-2621-15U3M camera of the second generation of the Haichen Water Star Pro series is selected; the infrared thermal imager 63 requires: the temperature measurement can be realized, the temperature measurement range is 0-500℃ (wavelength is 8-14um), the temperature measurement accuracy is: ±1.5℃ (0~100℃) or ±2% (<0 and >100℃), and the refrigeration type infrared thermal imager is selected according to the requirement.

[0087] It should be noted that the heating element inside the annular heater 2 is wound by a high-resistance alloy wire, and the front surface of the annular heater 2 is arranged opposite to the spherical surface of the grid 4 along the left-right direction x, so as to improve the heating effect of the annular heater 2 on the grid 4.

[0088] It should be noted that the probe 5 is generally selected from a material with a small thermal deformation coefficient such as ceramic, because the probe 5 pasted on the surface of the grid 4 may be affected by the temperature during the heating process of the grid 4, so a material which does not deform or deforms little in this temperature range and does not affect the deformation measurement of the grid 4 is selected as much as possible.

[0089] The grid 4 includes a screen grid 41 and an accelerating grid 42, and the screen grid 41 and the accelerating grid 42 are arranged in a staggered manner along the left-right direction x. Figure 1 The probe 5 includes a screen grid probe 8 and an accelerating grid probe 9; a plurality of screen grid probes 8 are bonded with the screen grid 41 to form a screen grid probe annular group 15, and a plurality of accelerating grid probes 9 are bonded with the accelerating grid 42 to form an accelerating grid probe annular group 16; the first annular group and the second annular group are arranged alternately on the grid 4 along the front-back direction y.

[0090] It should be noted that the screen grid 41 and the accelerating grid 42 are in a stacked structure, and there is an obstruction between the screen grid 41 and the accelerating grid 42, so a plurality of screen grid probes 8 are bonded with the screen grid 41 to form a screen grid probe annular group 15, and a plurality of accelerating grid probes 9 are bonded with the accelerating grid 42 to form an accelerating grid probe annular group 16; the screen grid probe annular group 15 and the accelerating grid probe annular group 16 are arranged alternately on the grid 4 along the front-back direction y, which can reflect the deformation amount of each layer of the grid 4 from the center to the edge of the grid 4 along the radial direction as much as possible during the measurement process, and provide a certain structural basis for obtaining three-dimensional deformation information of the grid 4.

[0091] It also includes a vacuum pumping device 18 connected with the environment box 1; the vacuum pumping device 18 includes a vacuum pump and a molecular pump.

[0092] It should be noted that the vacuum device 18 ensures the vacuum degree in the environment box 1, and as much as possible to simulate the vacuum environment of the ion thruster working state; during the measurement process, the vacuum pump realizes the extraction of the vacuum in the environment box 1, and the molecular pump is used to maintain the vacuum degree in the environment box 1.

[0093] It should be noted that along the left-right direction, the vacuum device 18 can be arranged opposite to the observation window 7, and connected with the environment box 1 by using a vacuum flange. The vacuum flange connection can not only ensure the safety of the environment box 1 and the vacuum device 18, but also ensure the air tightness of the environment box 1 after installation, and ensure the vacuum degree of the experimental environment.

[0094] Further comprising a cooling system, the cooling system comprises a circulating water tank 10 arranged on the inner wall of the environment box 1 and a cooling pipe 14 or a cooling fin arranged at the edge of the grid electrode 4.

[0095] It should be noted that the circulating water tank 10 is uniformly arranged on the inner wall of the environment box 1, and the water inlet pipe 101 and the water outlet pipe 102 are arranged to circulate water and complete the circulating cooling in the environment box 1 during the measurement process; the cooling pipe 14 or the cooling fin at the edge of the grid electrode 4 is only schematically illustrated by taking the cooling pipe 14 as an example in the drawing, the cooling pipe 14 is arranged around the edge of the grid electrode 4, one end of the cooling pipe 14 is a water inlet 141, and the other end is a water outlet 142, realizing the circulating cooling of the grid electrode 4, and providing a certain basis for measuring the temperature and deformation of the grid electrode 4 during the cooling process.

[0096] It can be understood that the cooling system comprises the circulating water tank 10 arranged on the inner wall of the environment box 1 and the cooling pipe 14 or the cooling fin arranged at the edge of the grid electrode 4, after the annular heater 2 is turned on, the cooling device is turned on, and cooperates with the annular heater 2 to simulate the real environment of the grid electrode 4 in the ion thruster working environment.

[0097] It can be understood that the ion thruster grid 4 temperature and deformation field measurement system and method provided by the application includes an environmental box 1, a ring heater 2 is arranged in the environmental box 1 to simulate heat generated in the working process of the thruster, the center of the grid 4 is opposite to the center of the ring heater 2 to simulate the real working condition of the ion thruster as much as possible; a probe 5 is introduced as an information carrier, which is bonded with the surface of the grid 4 to facilitate observation and capture of temperature and deformation information of the grid 4; the environmental box 1 is provided with an observation window 7, so that the infrared thermal imager 63 and the high-resolution camera group pass through the beam splitter 61 to simultaneously shoot the probe 5, the temperature information of the grid 4 is measured by using the infrared thermal imager 63, the deformation information of the grid 4 is measured by using the binocular vision ranging principle of the high-resolution camera 62, the infrared image and the visible light image are simultaneously shot, and the temperature and deformation field measurement are realized; the visible light image and the thermal image obtained are processed by the digital image processing system, so that the three-dimensional deformation information and the temperature information of the grid 4 are obtained, finally the thermal deformation and the temperature change rule of the grid 4 are summarized, the influence of temperature on the thermal deformation of the grid 4 is analyzed, and the grid 4 can be correspondingly structurally modified and designed according to the measured information.

[0098] Embodiment 4

[0099] The following Figures 1 to 8 A specific embodiment of the ion thruster grid 4 temperature and deformation field measurement system provided by the application is described below.

[0100] The temperature detection device 17 includes a thermocouple 171 and a data recorder 172 connected electrically, the thermocouple 171 includes a grid thermocouple 1711 and a probe thermocouple 1712, the grid thermocouple 1711 is bonded with the surface of the grid 4, the probe thermocouple 1712 is bonded with the front end 52, and the grid thermocouple 1711 and the probe thermocouple 1712 are alternately arranged along the left-right direction x.

[0101] It can be understood that the temperature detection device 17 provides a basis for the experimental calibration process of measuring the temperature of the front end 52 of the probe 5 and the surface of the grid 4 before measurement, the grid thermocouple 1711 is bonded with the surface of the grid 4, the probe thermocouple 1712 is bonded with the front end 52, and the grid thermocouple 1711 and the probe thermocouple 1712 are alternately arranged along the left-right direction x, so that the temperature of the front end 52 of the probe 5 and the temperature of different positions of the grid 4 from the center to the edge in the radial direction can be measured in the experimental calibration process, more accurate analysis is ensured, and the comprehensiveness of measurement and the accuracy of the experiment are improved.

[0102] Embodiment 5

[0103] Referring to Figures 1 to 11The application provides a temperature and deformation field measurement method for a grid assembly of an ion thruster, which is applied to the temperature and deformation field measurement system for the grid assembly of the ion thruster and comprises the following steps:

[0104] S2: a vacuumizing device 18 connected with the environment box 1 is turned on to adjust the vacuum degree in the environment box 1;

[0105] S3: a cooling system arranged on the inner wall of the grid 4 and the environment box 1 is turned on;

[0106] S4: the annular heater 2 is turned on;

[0107] S5: the image acquisition system 6 photographs the probe 5 and records the photographing result;

[0108] S6: the annular heater 2 is turned off;

[0109] S7: the image acquisition system 6 photographs the probe 5 and records the photographing result;

[0110] S8: the cooling system and the vacuumizing device 18 are turned off, and the image acquisition system 6 stops photographing;

[0111] S9: a digital image processing system processes the photographing result of the image acquisition system 6.

[0112] Specifically, the temperature and deformation field measurement method for the grid 4 of the ion thruster comprises the following steps: S2: a vacuumizing device 18 connected with the environment box 1 is turned on to adjust the vacuum degree in the environment box 1;

[0113] It should be noted that the vacuumizing device 18 is turned on, and the vacuum pump is used to vacuumize the environment in the environment box 1 to reach the required vacuum degree (1*10-4 Pa), so as to simulate the real working environment of the ion thruster and provide an environmental basis for the subsequent measurement process; the molecular pump is used to keep the pressure in the cabin, so as to avoid some measurement errors caused by unstable environment.

[0114] S3: a cooling system arranged on the inner wall of the grid 4 and the environment box 1 is turned on;

[0115] It should be noted that after the vacuum degree in the environment box 1 reaches the requirement, the cooling system is immediately turned on to continuously add cold water to the water inlet pipe 101 of the circulating water tank 10 and the water inlet pipe 141 of the cooling pipe 14, so as to cool the environment box 1 and the grid 4, further maintain the stability of the environment in the environment box 1, and reduce the influence of environmental factors on the subsequent measurement process.

[0116] S4: the annular heater 2 is turned on;

[0117] It should be noted that the annular heater 2 is turned on to further simulate the thermal radiation environment in which the grid 4 is located when the ion thruster works.

[0118] S5: The image acquisition system 6 photographs and records the results of the photographing of the probe 5;

[0119] It should be noted that after the image acquisition system 6 is turned on, the phenomenon that the displacement of the probe 5 suddenly increases from zero will be photographed. After the vacuum degree in the environmental box 1 remains stable, the displacement of the probe 5 in the two-dimensional plane will also remain stable. After the measurement is completed, the image in the stable state in the environmental box 1 is selected for image processing and digital analysis, so as to ensure the accuracy of the experimental results.

[0120] It should be noted that the image acquisition system 6 uses a high-resolution camera 62, which is a large constant water star second generation Pro series ME2P-2621-15U3M camera, and the image recording software used in cooperation is Galaxy Viewer. Therefore, the image acquisition system 6 can record the results of the photographing, so as to ensure the comprehensiveness of the statistics in the measurement process.

[0121] S6: Turn off the annular heater 2;

[0122] S7: The image acquisition system 6 photographs and records the results of the photographing of the probe 5;

[0123] It should be noted that after S6: the annular heater 2 is turned off, the image acquisition system 6 continues to photograph and record the results of the photographing of the probe 5, so as to collect the thermal images of the temperature changes of the grid 4 and the visible light images of the deformation in the cooling process, ensure the integrity of the measurement process, reduce the experimental error, and ensure the scientificity of the measurement.

[0124] S8: Turn off the cooling system and the vacuumizing device 18, and stop the photographing of the image acquisition system 6;

[0125] It should be noted that the opening time of the annular heater 2 is expected to be within 10 minutes. The image acquisition system 6 continuously photographs the images of the grid 4 in the measurement process. When the measured deformation amount of the grid 4 remains stable, it can be determined that the deformation process of the grid 4 is completed, the annular heater 2 can be turned off, and the deformation images and temperature change images of the grid 4 in the running process of the cooling system are continuously collected. After the deformation amount remains stable again, it can be determined that the entire measurement process is completed.

[0126] S9: The digital image processing system processes the results of the photographing of the image acquisition system 6.

[0127] It should be noted that the present application does not make specific limitation to the specific image processing software used, and in the present embodiment, only the image processing software based on Matlab is used for illustrative purposes. The shooting results of the probe 5 shot and recorded by the image acquisition system 6 are processed by the image processing software based on Matlab to obtain the changes of the two-dimensional coordinate information of the mark point 521 of the probe 5 in the measurement process, and the three-dimensional space coordinates of the mark point 521 can be solved by using the "solution" command of Matlab according to the obtained two-dimensional coordinates, that is, the three-dimensional deformation of the grid electrode 4 in the measurement process is obtained.

[0128] It should be noted that first, the high-resolution camera 62 is used to collect the pictures of the probe 5 pasted on the grid electrode 4, and then the image processing algorithm (such as binarization, region division, etc.) is used to obtain the center coordinates of the mark point 521 of the front end 52 of the corresponding probe 5 imaged by the high-resolution camera 62 on the left and right sides, assuming that the coordinates of one of the probes 5 imaged by the high-resolution camera 62 are (xL, yL), and the coordinates of the corresponding symmetric high-resolution camera 63 are (xR, yR), and then the three-dimensional coordinates (X, Y, Z) of the probe point in space are obtained by using the "solution" command in Matlab. It should be noted that during the measurement process, the infrared thermal imager 63 of the image acquisition system 6 shoots the thermal image of the front end 52 of the probe 5 to obtain the temperature value of the front end 52 of the probe 5.

[0129] It should be noted that the infrared thermal imager 63 mainly based on the infrared radiation energy distribution image emitted by the object, when the object absorbs or reflects the infrared radiation energy, these energies will produce corresponding strong and weak electric signals in the detector. These signals are amplified and shaped by the amplifier and shaping circuit, and then input to the integrator for integration processing. After being processed by the microprocessor, these signals are converted into corresponding temperature values.

[0130] It should be noted that the images shot by the infrared thermal imager 63 can be saved in the form of thermal images and ASCII codes respectively, the form of thermal images can more intuitively judge the temperature of each region in the image, and the stored ASCII code form saves the temperature value of each pixel point in the image, so when the specific temperature value is obtained, the ASCII code of the corresponding pixel point can be directly read.

[0131] It should be noted that before measuring the temperature and deformation of the grid electrode 4, the high-resolution camera 62 and the infrared thermal imager 63 of the image acquisition system 6 need to be calibrated to obtain their internal and external parameters. The internal parameters include the focal length, principal point coordinates and distortion coefficient of the camera; the camera external parameters include the rotation matrix and translation matrix, which are used for image processing software to process the collected visible light images and thermal images.

[0132] It should be noted that in order to quantitatively extract and measure the geometric information and motion information of the space object from the image in the camera measurement, the mutual correspondence between the image point position in the image and the space object point position must be established, and the correspondence is determined by the imaging model of the camera system and the spatial position of the camera, that is, the internal and external parameters of the camera. Since the optical center, optical axis and focal length of the camera are parameters of the mathematical analysis model, the parameters of the camera measurement system need to be determined through experiment and calculation, which is the camera measurement system calibration. Camera system calibration is one of the most basic and important works of camera measurement. Since the object distance is tens or even thousands of times the focal length for most camera measurements, a small error in the internal and external system parameters of the camera system may be magnified thousands of times in the measurement results. Therefore, in order to improve the precision of measurement, the camera system must be calibrated with high precision.

[0133] Before using the high-resolution camera 62 to shoot the probe 5 image for solving, the internal and external parameters of the high-resolution camera 62 must be calibrated first. The calibration can be performed by various software programming, and the specific software is not limited in this specification. In this embodiment, only the calibration using the Matlab self-contained calibration toolbox is exemplarily described. When using, only the two-dimensional checkerboard images shot at different angles need to be imported, and the toolbox can automatically complete the checkerboard recognition and internal and external parameter calibration. The internal and external parameters obtained after calibration are stored in a file, and when the two-dimensional coordinates of the left and right images are used to solve the three-dimensional coordinates, the data in the file need to be inputted to solve the three-dimensional space coordinates. The internal parameters obtained by calibration are mainly used for image correction and optimization to eliminate the influence of image distortion on the measurement results; the external parameters describe the relative position and direction of the two cameras, that is, the position and attitude of the camera in the world coordinate system. Through the external parameters, the image information observed by the camera can be converted to the real world coordinate system, so as to realize the accurate measurement and reconstruction of the spatial position and shape of the object.

[0134] It can be understood that the ion thruster grid 4 temperature and deformation field measurement system and method provided by the application includes an environmental box 1, a ring heater 2 is arranged in the environmental box 1 to simulate heat generated in the working process of the thruster, the center of the grid 4 is opposite to the center of the ring heater 2 to simulate the real working condition of the ion thruster as much as possible; a probe 5 is introduced as an information carrier, which is bonded with the surface of the grid 4 to facilitate observation and capture of temperature and deformation information of the grid 4; the environmental box 1 is provided with an observation window 7, so that the infrared thermal imager 63 and the high-resolution camera group pass through the beam splitter 61 to simultaneously shoot the probe 5, the temperature information of the grid 4 is measured by using the infrared thermal imager 63, the deformation information of the grid 4 is measured by using the binocular vision ranging principle of the high-resolution camera, the thermal image and the visible light image are simultaneously shot, and the temperature and deformation field measurement are realized; the visible light image and the thermal image obtained are processed by the digital image processing system, so that the three-dimensional deformation information and the temperature information of the grid 4 are obtained, finally the thermal deformation and the temperature change rule of the grid 4 are summarized, the influence of temperature on the thermal deformation of the grid 4 is analyzed, and the grid 4 can be correspondingly structurally modified and designed according to the measured information.

[0135] Embodiment 6

[0136] The following Figures 1 to 11 A specific embodiment of the ion thruster grid 4 temperature and deformation field measurement method provided by the application is described below.

[0137] Before S2: the vacuumizing device is opened, S1: experimental calibration is further included, S1: experimental calibration includes the following steps:

[0138] S11: the ring heater 2 is opened;

[0139] S12: the grid temperature value measured by the grid thermocouple connected to the surface of the grid 4 and the probe temperature value measured by the probe thermocouple connected to the front end 52 are recorded by using the data recorder;

[0140] S13: the ring heater 2 is closed;

[0141] S14: the grid temperature value and the probe temperature value are analyzed by using the digital image processing system, and the functional relationship between the grid temperature value and the probe temperature value is obtained.

[0142] It should be noted that after the surface temperature value of the grid 4 and the temperature value of the front end 52 of the probe 5 are obtained by using the data recorder, the parameters of the heat conduction model can be solved by using the Matlab software according to the heat conduction equation (i.e. Fourier equation) and the measured temperature data, so that the heat conduction relationship between the temperature of the front end 52 of the probe 5 and the temperature of the grid 4 is obtained.

[0143] It can be understood that the experimental calibration process first starts the heater, uses the data logger to record the temperature values of the grid 4 and the front end 52 of the probe 5 during the heating process; the function relationship between the two is fitted through Matlab software or other programming software; finally, after obtaining the temperature of the front end 52 of the probe 5 using the infrared thermal imager 63, the fitted function can accurately obtain the temperature value of the surface of the grid 4 during the measurement process.

[0144] Embodiment 7

[0145] The following Figures 1 to 11 to illustrate a specific embodiment of the ion thruster grid 4 temperature and deformation field measurement method provided by the present application, which is based on embodiment 6 and details S5 / S7: The image acquisition system 6 shoots and records the shooting results of the probe 5, and S9: The image processing system processes the shooting results of the image acquisition system 6:

[0146] S5 / S7: The image acquisition system 6 shoots and records the shooting results of the probe 5, including:

[0147] The infrared thermal imager 63 shoots the probe 5, obtains the thermal image of the front end 52, and records it;

[0148] The high-resolution camera 62 shoots the visible light image of the probe 5 through the beam splitter 61 and records it.

[0149] It should be noted that during the measurement process, the infrared thermal imager 63 of the image acquisition system 6 shoots the thermal image of the front end 52 of the probe 5, and obtains the temperature value of the front end 52 of the probe 5.

[0150] It should be noted that the infrared thermal imager 63 mainly based on the infrared radiation energy distribution image emitted by the object, when the object absorbs or reflects the infrared radiation energy, these energies will produce corresponding strong and weak electric signals in the detector. These signals are amplified and shaped through an amplifier and a shaping circuit, and then input to an integrator for integration processing. After being processed by a microprocessor, these signals are converted into corresponding temperature values, and finally displayed in the form of visible thermal images, so the infrared thermal imager 63 can convert the invisible infrared energy emitted by the object into visible thermal images, and different colors on the above represent different temperatures of the measured object.

[0151] It should be noted that while collecting the infrared thermal image of the probe 5, through the designed beam splitter 61 system, after triggering the collection control, the synchronous collection of the visible light image of the probe 5 in different light paths can be realized, so as to obtain the deformation information of the grid 4;

[0152] According to the temperature image of the probe 5 pasted on the surface of the grid 4 and the displacement image of the probe 5 in the measurement process, the temperature and deformation of the corresponding position of the grid 4 can be matched and corresponded, so that the temperature and deformation of the grid 4 correspond in time and space, and finally the same field measurement is realized, and the measurement accuracy is improved.

[0153] S9: The digital image processing system processes the shooting result of the image acquisition system 6, which includes:

[0154] The thermal image is analyzed by using the image processing software, and the temperature change information of the grid 4 is obtained.

[0155] It should be noted that in the present example, the image processing software based on Matlab is used to solve the heat conduction function of the temperature value of the front end 52 of the probe 5 collected by the infrared thermal imager 63 on the basis of experimental calibration, and the temperature value of the grid 4 in the measurement process is obtained.

[0156] It should be noted that in the formal measurement, the probe 5 and the grid 4 do not need to be pasted with thermocouples, and the image data of the front end 52 of the probe 5 obtained from the infrared thermal imager 63 and the corresponding saved temperature data can be directly obtained. The temperature value of the front end 52 of the probe 5, and then according to the temperature heat conduction relationship between the front end 52 of the probe 5 and the surface of the grid 4 obtained in S1: experimental calibration, the temperature information of the surface of the grid 4 can be directly solved.

[0157] The visible light image is analyzed by using the image processing software, and the deformation information of the grid 4 in the three-dimensional space is obtained.

[0158] It should be noted that the analysis of the visible light image by the image processing software can be performed by various software, and the specific software is not limited in the present specification. In the present embodiment, only the analysis of the visible light image by the image processing software based on Matlab is used as an exemplary description. The shooting result recorded by the image acquisition system 6 on the probe 5 is processed by the image processing technology based on Matlab, and the left and right direction pictures of the probe 5 are processed, so as to obtain the change of the two-dimensional coordinate information of the mark point 521 of the probe 5 in the measurement process. According to the obtained two-dimensional coordinates, the three-dimensional space coordinates of the mark point 521 can be solved, that is, the three-dimensional deformation of the grid 4 in the measurement process is obtained.

[0159] From the above embodiment, it can be known that the ion thruster grid temperature and deformation same field measurement system and method provided by the present application at least realizes the following beneficial effects:

[0160] The application provides a grid temperature and deformation simultaneous field measurement system and method of an ion thruster, which comprises an environmental box 1, a ring heater 2 arranged in the environmental box 1 to simulate heat generated in the working process of the thruster, and a grid 4, the center of which is opposite to the center of the ring heater 2, so that each part of the grid 4 is uniformly heated when heated, and the grid 4 is better simulated in the actual situation; a probe 5 is introduced as an information carrier, which is bonded to the surface of the grid 4, so as to facilitate observation and capture of temperature and deformation information of the grid 4; the environmental box 1 is provided with an observation window 7, so that an infrared thermal imager 63 and a high-resolution camera group pass through a beam splitter 61 to simultaneously shoot the probe 5, the temperature information of the grid 4 is measured by the infrared thermal imager 63, the deformation information of the grid 4 is measured by the high-resolution camera group by using the binocular vision ranging principle, the infrared image and the visible light image are simultaneously shot, and the temperature and deformation are simultaneously measured; the vacuum degree of the environmental box 1 is guaranteed to reach the vacuum degree requirement of the actual working condition of the grid 4 by maintaining the vacuum environment during measurement, so that the simulation experiment environment is realized; the real thermal radiation is applied to the grid 4 by cooperation of the ring heater 2 and a cooling system, a temperature change thermal image and a visible light image of deformation of the grid 4 are shot and recorded by an image acquisition system 6, visible light images and thermal images obtained are processed by a digital image processing system, so that three-dimensional deformation information and temperature information of the grid 4 are obtained, finally, the thermal deformation and temperature change rule of the grid 4 are summarized, the influence of temperature on the thermal deformation of the grid 4 is analyzed, and the grid 4 can be correspondingly reformed and designed according to the measured information.

[0161] Although some specific embodiments of the application have been described in detail by examples, those skilled in the art should understand that the above examples are only for illustration, but not for limiting the scope of the application. Those skilled in the art should understand that the above embodiments can be modified without departing from the scope and spirit of the application. The scope of the application is defined by the appended claims.

Claims

1. A temperature and deformation co-field measurement system of ion thruster grid assembly, comprising: an environmental box; a ring heater fixedly connected with the inner wall of the environmental box through a fixed rod; a grid arranged in the environmental box, the center of the grid and the center of the ring heater being oppositely arranged along a left-right direction; a probe comprising a rear end and a front end oppositely arranged along the left-right direction, the front end being spherical, a mark point being arranged on the front end away from the center of one side of the grid along the left-right direction, and the rear end being bonded with the surface of the grid; a viewing window arranged on the box body of the environmental box opposite to the grid along the left-right direction; an image acquisition system comprising a beam splitter, a high-resolution camera group and an infrared thermal imager, the beam splitter being oppositely arranged with the viewing window along the left-right direction, and the infrared thermal imager being arranged at the end of the beam splitter away from the viewing window; along a front-rear direction, the high-resolution camera group comprises high-resolution cameras oppositely arranged on both sides of the beam splitter, and the front-rear direction is perpendicular to the left-right direction; a temperature detection device, which is an experimental calibration for measuring the surface temperature of the grid and the front end of the probe before measurement, the temperature detection device comprising a thermocouple and a data logger connected electrically, the thermocouple comprising a grid thermocouple and a probe thermocouple, the grid thermocouple being bonded with the surface of the grid, and the probe thermocouple being bonded with the front end, the grid thermocouple and the probe thermocouple being alternately arranged along the left-right direction; the temperature value of the front end of the probe acquired by the infrared thermal imager is solved based on the experimental calibration by a heat conduction function to obtain the temperature value of the grid in the measurement process; a digital image processing system comprising image processing software, the digital image processing system being communicatively connected with the image acquisition system.

2. The ion thruster grid assembly temperature and distortion co-simulation system of claim 1, wherein, The beam splitter comprises lenses, a dichroic beam splitter and a triangular prism arranged in sequence along the left-right direction.

3. The ion thruster grid assembly temperature and distortion co-field measurement system of claim 1, wherein, The grid comprises a screen grid and an acceleration grid, the screen grid and the acceleration grid being overlapped along the left-right direction; the probe comprises a screen grid probe and an acceleration grid probe; a plurality of screen grid probes are bonded with the screen grid to form a screen grid probe ring group; a plurality of acceleration grid probes are bonded with the acceleration grid to form an acceleration grid probe ring group; along the front-rear direction, the screen grid probe ring group and the acceleration grid probe ring group are alternately arranged on the grid.

4. The ion thruster grid assembly temperature and distortion co-simulation system of claim 1, wherein, Further comprising a vacuum pumping device flange-connected with the environmental box, the vacuum pumping device comprising a vacuum pump and a molecular pump.

5. The ion thruster grid assembly temperature and distortion co-field measurement system of claim 1, wherein, Further comprising a cooling system comprising a circulating water tank arranged on the inner wall of the environmental box and a cooling pipe or a heat sink arranged at the edge of the grid. 6.A temperature and deformation co-field measurement method of ion thruster grid assembly, applied to the temperature and deformation co-field measurement system of ion thruster grid assembly according to any one of claims 1-5, comprising the steps of: turning on the vacuum pumping device connected with the environmental box to adjust the vacuum degree in the environmental box. Turning on a cooling system arranged on the inner wall of the gate and the environmental box; Turning on the annular heater; The image acquisition system takes a picture of the probe and records the picture result; Turning off the annular heater; The image acquisition system takes a picture of the probe and records the picture result; Turning off the cooling system and the vacuum device, and the image acquisition system stops taking pictures; The digital image processing system processes the picture result of the image acquisition system.

7. The ion thruster grid assembly temperature and distortion co-simulation method of claim 6, wherein, Before the vacuum device is turned on, the method further comprises an experimental calibration, which comprises the following steps: Turning on the annular heater; Using a data recorder to record the gate temperature value measured by the gate thermocouple connected to the surface of the gate and the probe temperature value measured by the probe thermocouple connected to the front end; Turning off the annular heater; The digital image processing system analyzes the gate temperature value and the probe temperature value to obtain the functional relationship between the gate temperature value and the probe temperature value.

8. The ion thruster grid assembly temperature and distortion co-simulation method of claim 6, wherein, The image acquisition system takes a picture of the probe and records the picture result, which comprises: The infrared thermal imager takes a picture of the probe to obtain the thermal image of the front end and records it; The high-resolution camera takes a visible light image of the probe through the beam splitter and records it.

9. The ion thruster grid assembly temperature and distortion co-simulation method of claim 6, wherein, The digital image processing system processes the picture result of the image acquisition system, which comprises: Using the image processing software to analyze the thermal image to obtain the temperature change information of the gate; Using the image processing software to analyze the visible light image to obtain the deformation information of the gate in the three-dimensional space.

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