Speed measurement system for laser-driven flyer

Abstract

The embodiment of the invention provides a speed measurement system for a laser-driven flyer. The speed measurement system for the laser-driven flyer comprises a driving laser, an illumination laser and a high-speed camera, the driving laser is used for emitting driving laser and generating a flyer through the driving laser; the illumination laser is used for generating a light curtain; wherein the light curtain covers the flight path of the flyer; the high-speed camera is used for shooting at least two flyer photos within the coverage range of the light curtain and sending the at least two flyer photos to the upper computer; and the upper computer determines flyer speed information based on the at least two flyer photos. A high-speed photographing device is matched with a continuous laser lighting device to photograph the flying piece launching process, the photographing time sequence is controlled through a trigger system, accurate measurement of the speed is achieved through position changes of flying pieces in different images, and therefore the accuracy of flying piece speed measurement is improved.

Description

Technical Field

[0001] The embodiments of this specification relate to the technical field of flying piece speed measurement, and in particular to a speed measurement system for laser driven flying pieces. Background Art

[0002] Laser-driven flyer technology uses a high-power pulsed laser beam to irradiate a metal film deposited on a substrate material. After the metal film absorbs the energy of the incident laser beam, it ablates and vaporizes to form a micro-ablation cavity, and generates high-temperature and high-pressure plasma on its inner surface. The plasma continues to absorb the energy of the laser beam and expands, eventually driving the remaining unevaporated film out to form flyers. After more than 20 years of development, laser-driven flyer technology has been successfully applied to the study of material equation of state, the study of dynamic response characteristics of materials under high strain rates, the study of explosive detonation technology, and the simulation of space debris.

[0003] The currently widely used speed measurement method is to deploy two lasers and photosensitive sensors on the flight path of the flying piece. When the flying piece passes through the two light curtains, it will block the light curtains and cause the photosensitive sensor signal output to change. The flying piece speed is calculated by the time when the two sensor signals change and the distance between the sensors.

[0004] This method requires accurate adjustment of the laser light curtain, the flying piece path and the position of the photosensitive sensor so that the flying piece can be effectively blocked. The size and shape of the flying piece have a great influence on the blocking effect and signal strength. In addition, the signal is read as a fluctuating curve on the oscilloscope, and the extreme value of the reading curve needs to be manually selected. In summary, this method is complex to operate and difficult to debug. In addition, data reading relies heavily on personal experience, and the flying piece speed measurement is not accurate enough.

[0005] Since the size of the flying piece is very small, the effect of blocking the laser is also small. If the laser is too thick, the change of the photosensitive sensor signal is not obvious; if the laser is too thin, the position accuracy of the flying piece and the photosensitive sensor is required to be high. In addition, the reading of the photosensitive sensor is easily affected by factors such as plasma during the laser driving process, resulting in abnormal signal fluctuations.

[0006] Therefore, a better solution is urgently needed. Summary of the invention

[0007] In view of this, the embodiments of this specification provide a speed measurement system for a laser-driven flyer to solve the technical defects existing in the prior art.

[0008] According to a first aspect of an embodiment of this specification, there is provided a speed measurement system for a laser-driven flying sheet, comprising: a driving laser, an illumination laser, and a high-speed camera;

[0009] The driving laser is used to emit driving laser, and the flying flakes are generated by the driving laser;

[0010] The illumination laser is used to generate a light curtain; wherein the light curtain covers the flight path of the flying sheet;

[0011] The high-speed camera is used to take at least two flying film photos within the coverage area of ​​the light curtain, and send at least two flying film photos to the host computer;

[0012] The host computer determines the flying film speed information based on at least two flying film photos.

[0013] In a possible implementation, it also includes a flying chip target;

[0014] Accordingly, the flying flakes are generated by driving the laser, including:

[0015] Flying flakes are generated by driving laser to irradiate a flying flake target, wherein the flying flake target is a metal film.

[0016] In a possible implementation, a beam control lens is also included;

[0017] Beam steering lenses are used to amplify the illumination laser to produce a light curtain.

[0018] In a possible implementation, a filter is also included;

[0019] The filter is used to filter out other light entering the high-speed camera; wherein the other light is light other than the illumination laser.

[0020] In a possible implementation, it also includes a signal trigger;

[0021] The signal trigger is used to control the driving laser to emit the driving laser, and at a target time after the driving laser emits the driving laser, control the high-speed camera to take at least two flying film photos within the coverage range of the light curtain.

[0022] In a possible implementation manner, before determining the flying film speed information based on at least two flying film photos, the method further includes:

[0023] Determine the estimated speed of the flying piece;

[0024] The field of view width and shooting frequency of the high-speed camera are determined based on the estimated speed of the flying pieces.

[0025] In a possible implementation, the field of view width and shooting frequency of the high-speed camera are determined based on the predicted flying piece speed, including:

[0026]

[0027] Among them, L represents the field of view width, N represents the shooting frequency, and V represents the estimated flying film speed.

[0028] In a possible implementation, determining the flying film velocity information based on at least two flying film photos includes:

[0029] Determining the flyer spacing based on at least two flyer photographs;

[0030] The flying piece speed information is determined based on the flying piece spacing and the shooting frequency.

[0031] In a possible implementation, the wavelength of the illumination laser is 532 nm.

[0032] In a possible implementation, the estimated flying speed is 3 km / s-15 km / s.

[0033] The embodiment of the present specification provides a speed measurement system for laser-driven flying films, wherein the speed measurement system for laser-driven flying films includes: a driving laser, an illumination laser, and a high-speed camera; the driving laser is used to emit the driving laser, and the flying films are generated by the driving laser; the illumination laser is used to generate a light curtain; wherein the light curtain covers the flight path of the flying films; the high-speed camera is used to take at least two photos of the flying films within the coverage of the light curtain, and send the at least two photos of the flying films to the host computer; the host computer determines the speed information of the flying films based on the at least two photos of the flying films. The flying film emission process is photographed by a high-speed photography device in conjunction with a continuous laser illumination device, and the shooting sequence is controlled by a trigger system, and the position change of the flying films in different images is used to achieve accurate speed measurement, thereby improving the accuracy of the flying film speed measurement. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 It is a schematic diagram of a speed measurement system for a laser-driven flying sheet provided in one embodiment of the present specification. DETAILED DESCRIPTION

[0035] Many specific details are described in the following description to facilitate a full understanding of this specification. However, this specification can be implemented in many other ways than those described herein, and those skilled in the art can make similar generalizations without violating the connotation of this specification, so this specification is not limited to the specific implementation disclosed below.

[0036] The terms used in one or more embodiments of this specification are only for the purpose of describing specific embodiments, and are not intended to limit one or more embodiments of this specification. The singular forms of "a" and "the" used in one or more embodiments of this specification and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings. It should also be understood that the term "and / or" used in one or more embodiments of this specification refers to and includes any or all possible combinations of one or more associated listed items.

[0037] It should be understood that although the terms first, second, etc. may be used to describe various information in one or more embodiments of this specification, this information should not be limited to these terms. These terms are only used to distinguish the same type of information from each other. For example, without departing from the scope of one or more embodiments of this specification, the first may also be referred to as the second, and similarly, the second may also be referred to as the first. Depending on the context, the word "if" as used herein may be interpreted as "at the time of" or "when" or "in response to determining".

[0038] In this specification, a speed measurement system for a laser-driven flying sheet is provided. This specification also relates to a **** device, a computing device, and a computer-readable storage medium, which are described in detail one by one in the following embodiments.

[0039] See also Figure 1 , Figure 1 A schematic diagram of a speed measurement system for a laser-driven flyer provided according to an embodiment of the present specification is shown, which specifically includes: a driving laser, an illumination laser and a high-speed camera.

[0040] Specifically, the driving laser is used to emit the driving laser to generate flying flakes; the illumination laser is used to generate a light curtain; wherein the light curtain covers the flight path of the flying flakes; the high-speed camera is used to take at least two photos of the flying flakes within the coverage area of ​​the light curtain, and send at least two photos of the flying flakes to the host computer; the host computer determines the flying flake speed information based on the at least two photos of the flying flakes.

[0041] The host computer may be a computer, a mobile phone, a tablet or other equipment with computing functions. The high-speed camera may be a high-speed photography camera.

[0042] In practical applications, see Figure 1 , 1 is the driving laser, 2 is the flying sheet target, 3 is the emitted flying sheets and their movement path, 4 is the continuous illumination laser, 5 is the beam control lens, 6 is the high-speed camera, 7 is the filter, 8 is the signal trigger, and 9 is the display computer.

[0043] In a possible implementation, a flyer target is also included; accordingly, generating flyers by driving the laser includes: generating flyers by driving the laser to irradiate the flyer target; wherein the flyer target is a metal film.

[0044] Specifically, laser-driven flying flake technology uses a high-power pulsed laser beam to irradiate a metal film deposited on a base material. After the metal film absorbs the energy of the incident laser beam, it undergoes ablation and vaporization to form a micro-ablation cavity, and generates high-temperature and high-pressure plasma on its inner surface. The plasma continues to absorb the energy of the laser beam and expands, eventually driving out the remaining unevaporated film to form flying flakes.

[0045] In a possible implementation, a beam control lens is also included; the beam control lens is used to amplify the illumination laser to generate a light curtain.

[0046] The illumination laser light may be generated by a laser for illumination.

[0047] In practical applications, the range of the light curtain on the flying sheet path is controlled by adjusting the distance between the laser and its control beam control lens, so that the light curtain covers as large a flying sheet path as possible and does not directly enter the lens of the high-speed camera 6.

[0048] In a possible implementation, a filter is also included; the filter is used to filter out other light entering the high-speed camera; wherein the other light is light other than the illumination laser.

[0049] In practical applications, the filter 7 is selected according to the wavelength of the continuous illumination laser to ensure that only the laser with this wavelength can enter the camera.

[0050] For example, if the wavelength of the illumination laser is 532 nm, the filter 7 can only pass the light with a wavelength of 532 nm.

[0051] In a possible implementation, a signal trigger is also included; the signal trigger is used to control the driving laser to emit the driving laser, and at a target moment after the driving laser emits the driving laser, control the high-speed camera to take at least two flying film photos within the coverage range of the light curtain.

[0052] In practical applications, the driving laser 1 and the high-speed camera 6 are synchronously triggered by the signal trigger 8. The time to reach the shooting range can also be calculated by the estimated speed of the flying piece, and after the time has passed, the high-speed camera 6 is triggered to continuously shoot.

[0053] In a possible implementation, before determining the flying film speed information based on at least two flying film photos, the method further includes: determining an estimated flying film speed; and determining a field of view width and a shooting frequency of a high-speed camera based on the estimated flying film speed.

[0054] The estimated flying flake speed is the flying flake speed predicted by the driving laser 1. The estimated flying flake speed is 3 km / s-15 km / s.

[0055] Specifically, the field of view width and shooting frequency of the high-speed camera are determined based on the predicted flying piece speed, including:

[0056]

[0057] Among them, L represents the field of view width, N represents the shooting frequency, and V represents the estimated flying film speed.

[0058] In actual applications, the high-speed camera 6 cannot capture any images when there are no flying flakes because it is equipped with a filter; when the flying flakes enter the range of the illuminating laser, they will be illuminated by the laser and captured by the high-speed camera; by adjusting the position relationship between the laser 4 and the high-speed camera 6, the path of the flying flakes illuminated by the laser is within the camera field of view, and the field of view width L of the high-speed camera, the shooting frequency N of the high-speed camera and the estimated speed range V of the flying flakes satisfy the following relationship, ensuring that more than two flying flake images can be captured.

[0059] In a possible implementation, determining the flying film speed information based on at least two flying film photos includes: determining the flying film spacing based on at least two flying film photos; and determining the flying film speed information based on the flying film spacing and the shooting frequency.

[0060] In practical applications, the entire process of using this solution can be to adjust the drive system according to the conventional requirements of the laser-driven flying sheet experiment and determine the flying sheet emission path; adjust the illumination laser, lens and high-speed camera position according to the above requirements; set the signal trigger time according to the estimated flying sheet speed range to ensure that the camera has started continuous shooting when the flying sheet reaches the camera field of view; start the signal trigger to start the experimental process; read the image taken by the high-speed camera through the computer, measure the distance S between the flying sheets in the pictures taken twice, and calculate the flying sheet speed in combination with the camera shooting frequency N, V=SN.

[0061] For example, using 532nm wavelength continuous illumination laser and corresponding filters, i-SPEED727 high-speed camera, shooting frequency 150,000 frames and adjusting the shooting width to 25cm, it can capture three flying film images to meet the needs of ultra-high-speed flying film speed measurement of about 10km / s.

[0062] It should be noted that the parameters of the high-speed camera can be determined according to specific requirements, and the embodiments of this specification do not limit this.

[0063] The embodiment of the present specification provides a speed measurement system for laser-driven flying films, wherein the speed measurement system for laser-driven flying films includes: a driving laser, an illumination laser, and a high-speed camera; the driving laser is used to emit the driving laser, and the flying films are generated by the driving laser; the illumination laser is used to generate a light curtain; wherein the light curtain covers the flight path of the flying films; the high-speed camera is used to take at least two photos of the flying films within the coverage of the light curtain, and send the at least two photos of the flying films to the host computer; the host computer determines the speed information of the flying films based on the at least two photos of the flying films. The flying film emission process is photographed by a high-speed photography device in conjunction with a continuous laser illumination device, and the shooting sequence is controlled by a trigger system, and the position change of the flying films in different images is used to achieve accurate speed measurement, thereby improving the accuracy of the flying film speed measurement.

[0064] It should be noted that, for the above-mentioned method embodiments, for the sake of simplicity of description, they are all expressed as a series of action combinations, but those skilled in the art should be aware that the embodiments of this specification are not limited by the order of the actions described, because according to the embodiments of this specification, some steps can be performed in other orders or simultaneously. Secondly, those skilled in the art should also be aware that the embodiments described in the specification are all preferred embodiments, and the actions and modules involved are not necessarily required by the embodiments of this specification.

[0065] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0066] The preferred embodiments of this specification disclosed above are only used to help explain this specification. The optional embodiments do not describe all the details in detail, nor do they limit the invention to only the specific implementation methods described. Obviously, many modifications and changes can be made according to the content of the embodiments of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the embodiments of this specification, so that technicians in the relevant technical field can well understand and use this specification. This specification is only limited by the claims and their full scope and equivalents.

Claims

1. A speed measurement system for a laser driven flyer, characterized in that: include: driving lasers, illumination lasers, and high-speed cameras; The driving laser is used to emit driving laser light, and the flying flakes are generated by the driving laser light; The illumination laser is used to generate a light curtain; wherein the light curtain covers the flight path of the flying sheet; The high-speed camera is used to take at least two flying film photos within the coverage area of ​​the light curtain, and send the at least two flying film photos to the host computer; The host computer determines the flying film speed information based on the at least two flying film photos.

2. The speed measurement system for laser driven flyer according to claim 1, characterized in that: Also included is a flying chip target; Accordingly, the generating of flying flakes by the driving laser comprises: The flying flake target is irradiated by the driving laser to generate flying flakes; wherein the flying flake target is a metal film.

3. The speed measurement system for laser driven flyer according to claim 1, characterized in that: Also included is a beam steering lens; The beam control lens is used to amplify the illumination laser to generate the light curtain.

4. The speed measurement system for laser driven flyer according to claim 1, characterized in that: Also includes filters; The filter is used to filter out other light incident on the high-speed camera; wherein the other light is light other than the illumination laser.

5. The speed measurement system for laser driven flyer according to claim 1, characterized in that: Also includes signal triggers; The signal trigger is used to control the driving laser to emit the driving laser, and to control the high-speed camera to take at least two flying film photos within the coverage range of the light curtain at a target time after the driving laser emits the driving laser.

6. The speed measurement system for laser driven flyer according to claim 1, characterized in that: Before determining the flying film speed information based on the at least two flying film photos, the method further includes: Determine the estimated speed of the flying piece; The field of view width and shooting frequency of the high-speed camera are determined based on the estimated flying piece speed.

7. The speed measurement system for laser driven flyer according to claim 6, characterized in that: The method of determining the field of view width and shooting frequency of the high-speed camera based on the predicted flying piece speed includes: Wherein, L represents the field of view width, N represents the shooting frequency, and V represents the estimated flying film speed.

8. The speed measurement system for laser driven flyer according to claim 6, characterized in that: The determining of the flying film speed information based on the at least two flying film photos includes: Determining a flyer sheet spacing based on the at least two flyer sheet photos; Flying film speed information is determined based on the flying film interval and the shooting frequency.

9. The speed measurement system for laser driven flyer according to claim 8, characterized in that: The wavelength of the illumination laser is 532 nm.

10. The speed measurement system for laser driven flyer according to claim 6, characterized in that: The estimated speed of the flying piece is 3km / s-15km / s.

Images