Device and method for detecting the motion trajectory of cylindrical target material under laser action

Abstract

The present invention relates to the field of photoelectric detection technology, and specifically to a detection device and method for the motion trajectory of a cylindrical target under the action of a laser, comprising a laser for projecting a detection beam, and a beam expander, an adjustable circular aperture, a concave-convex lens group, a beam splitter, a first adjustable optical slit, a second adjustable optical slit, a first focusing lens, a first interference filter, and a first photoelectric sensor are coaxially installed in sequence along the direction of the detection beam projected by the laser. Compared with the traditional method, the technical solution solves the problem that the motion trajectory of the cylindrical target cannot be accurately measured due to slight rotation of the cylindrical target during the movement. The detection beam is divided into two beams by a beam splitter at the receiving end, which are converted into electrical signals by a photoelectric sensor after passing through a series of optical elements and received by an oscilloscope; by analyzing and processing the two electrical signals received by the oscilloscope, the measurement error caused by the rotation of the cylindrical target can be corrected.

Description

Technical Field

[0001] The invention relates to the field of photoelectric detection technology, and in particular to a detection device and a detection method for a motion trajectory of a cylindrical target material under the action of laser. Background Art

[0002] In the field of laser propulsion research, it is necessary to measure the initial velocity of the target material under the action of the laser. The mainstream detection methods include photography, beam deflection, pendulum, torsion pendulum, etc.

[0003] The patent document with patent announcement number: CN104457564B discloses a high-precision target material measurement system and method, including: a detection platform, an optical detection unit, a data collection and processing unit and a control unit. A hollow cavity is arranged in the middle of the detection platform, and a detachable movable plate is arranged on the hollow cavity, and the movable plate can completely cover the hollow cavity. At least one group of limit assemblies are arranged inside the hollow cavity, and the limit assemblies fix the target material and can drive the target material to rotate. The limit assemblies are connected to a driving device and driven by it; the optical detection unit includes a lens and a grating projection device. Since the detection platform and the optical detection unit are both active, high-precision three-dimensional detection of any position of target materials of different specifications and shapes can be achieved by controlling the direction and distance of their movement, and the limit assemblies can drive the target material to rotate, so that the target material does not need to be flipped during the detection process, thereby improving the detection efficiency.

[0004] As mentioned above, it can be classified as a photographic method. The photographic method is relatively simple, but in order to obtain the precise initial velocity of the target material, a high-speed camera with a high frame rate is often required, which is relatively expensive.

[0005] The initial velocity measured by the beam deflection method is an estimate, which is not applicable in scenarios where high accuracy is required. Although the pendulum method and the torsion pendulum method solve the problem of target material suspension, they often need to be used in conjunction with a camera during the specific measurement process, which also has its limitations.

[0006] Moreover, the beam deflection method, pendulum method, and torsion pendulum method are not suitable for detecting the initial velocity of the target material under the action of laser in a liquid environment. This is because in this scenario, the cavitation generated during the interaction between the laser and the target material makes the initial motion trajectory of the target material complicated.

[0007] How to accurately detect the initial velocity of the target material at a lower cost has become a problem. In order to solve this problem, Han Bing and others improved the traditional beam deflection method in 2016 and proposed a sheet beam transmission method, which monitored the motion trajectory of the target material on the straight line in the direction of the laser action and accurately obtained the initial velocity of the target material. However, in the specific experimental research process, when the laser fails to focus accurately on the center position of the target material propulsion surface, the target material is often accompanied by a slight rotation while being propulsed, which leads to errors in the measured target material motion trajectory. Summary of the invention

[0008] In order to overcome the above technical problems, the purpose of the present invention is to provide a device and method for detecting the motion trajectory of a cylindrical target under the action of laser, which solves the problem that the cylindrical target rotates slightly during movement, making it impossible to accurately measure its motion trajectory.

[0009] The purpose of the present invention can be achieved through the following technical solutions:

[0010] A device for detecting the motion trajectory of a cylindrical target under the action of laser, comprising a laser for projecting a detection beam, a beam expander, an adjustable circular aperture, a concave-convex lens group, a beam splitter, a first adjustable optical slit, a second adjustable optical slit, a first focusing lens, a first interference filter and a first photoelectric sensor are coaxially installed in sequence along the direction of the detection beam projected by the laser;

[0011] The detection device also includes a second focusing lens, a second interference filter, a second photoelectric sensor and an oscilloscope, wherein the second focusing lens, the second interference filter and the second photoelectric sensor are coaxially mounted on the beam splitter prism in sequence, and the mounting direction of the second focusing lens, the second interference filter and the second photoelectric sensor is perpendicular to the direction of the detection beam projected by the laser;

[0012] The incident surface of the beam splitter prism is kept perpendicular to the direction of the detection beam projected by the laser. After being dispersed by the beam splitter prism, the detection beam is emitted as two mutually perpendicular beams, wherein the projection direction of one beam is the same as the emission direction of the laser, and the other beam is projected toward the second focusing lens;

[0013] The output ends of the first photoelectric sensor and the second photoelectric sensor are connected to the first channel and the second channel of the oscilloscope respectively;

[0014] A cylindrical target and a multi-dimensional translation stage are arranged between the concave-convex lens group and the beam splitter prism, and the cylindrical target is suspended above the multi-dimensional translation stage.

[0015] Furthermore, the light intensity distribution of the detection light beam projected by the laser is Gaussian distribution.

[0016] Furthermore, the laser power stability of the detection light beam projected by the laser is not less than ±2.5%.

[0017] Furthermore, the central wavelengths of the light that can be transmitted through the first interference filter and the second interference filter are consistent with the wavelength of the laser.

[0018] Furthermore, the slit centerline of the first adjustable optical slit, the slit centerline of the second adjustable optical slit and the axis of the detection light beam projected by the laser together constitute a three-dimensional space, in which every two lines are perpendicular to each other.

[0019] Furthermore, the straight line where the axial direction of the cylindrical target material is located is in a plane formed by the slit center line of the first adjustable optical slit and the emission direction of the detection light beam projected by the laser.

[0020] Based on the above detection device, this scheme also proposes a method for detecting the motion trajectory of a cylindrical target under the action of a laser, and the detection method includes the following steps:

[0021] S1. Use a beam expander to expand the detection beam projected by the laser;

[0022] S2. Under the premise that no optical diffraction occurs, adjust the adjustable circular aperture so that the diameter of the circular detection light beam passing through the adjustable circular aperture is as small as possible;

[0023] S3, using a concave-convex lens group to expand the laser beam passing through the adjustable circular aperture, so that the diameter of the circular detection beam after expansion is not less than three times the height of the cylindrical target material;

[0024] S4. While ensuring that the cylindrical target does not block the detection beam, adjust the components so that the laser, beam expander, adjustable circular aperture, concave-convex lens group, beam splitter, first adjustable optical slit, second adjustable optical slit, first focusing lens, first interference filter and first photoelectric sensor are coaxial and at the same height, and adjust the first adjustable optical slit and the second adjustable optical slit to the maximum gap;

[0025] S5. Adjust the position of the beam splitter prism so that the direction of the detection beam reflected by it is perpendicular to the direction of the detection beam emitted by the laser, and then place the second focusing lens, the second interference filter, and the second photoelectric sensor in the direction of the reflected detection beam, and ensure that these optical elements are coaxial and at the same height as the beam splitter prism;

[0026] S6, by adjusting the position of the first photoelectric sensor, the detection light beam passing through the first focusing lens is focused on the photosensitive element of the first photoelectric sensor, at which time the signal voltage value of a channel of the oscilloscope reaches a maximum;

[0027] S7. By adjusting the position of the second photoelectric sensor, the laser beam passing through the second focusing lens is focused on the photosensitive element of the second photoelectric sensor. At this time, the signal voltage value of the second channel of the oscilloscope reaches the maximum, which is recorded as V 2max ;

[0028] S8. On the premise of ensuring that no optical diffraction occurs, reduce the slit width of the first adjustable optical slit so that the detection beam passing through the adjustable optical slit is the thinnest. At this time, the slit centerline of the first adjustable optical slit should be in the radial direction of the circular detection beam, and the slit width of the slit centerline of the first adjustable optical slit should be smaller than the circular surface radius of the cylindrical target. At this time, the detection beam passing through the first adjustable optical slit is a "straight-shaped" beam with a relatively uniform light intensity distribution. The slit width of the first adjustable optical slit at this time point is recorded as S1;

[0029] S9, reduce the slit width of the second adjustable optical slit until it is smaller than the height of the cylindrical target. At this time, the slit centerline of the second adjustable optical slit should also be in the radial direction of the circular detection beam, and the slit centerline of the second adjustable optical slit should remain perpendicular to the slit centerline of the adjustable optical slit. The slit width of the second adjustable optical slit at this time point is recorded as S2, and the signal voltage value of the oscilloscope channel 1 at this time is recorded as V 1max ;

[0030] S10. Use a shield to completely block the detection beam, and record the signal voltage value of the oscilloscope channel 1 as V 1min , remove the obstruction;

[0031] S11, by adjusting the multi-dimensional translation stage, the axial direction of the cylindrical target material is placed in the plane formed by the slit centerline of the first adjustable optical slit and the direction of the detection light beam emitted by the laser as much as possible;

[0032] Then move the cylindrical target along the straight line where the cylindrical axis is located, towards the direction close to the detection beam, and observe the signal voltage value of the first channel of the oscilloscope at the same time. When the cylindrical target begins to block the detection beam, the signal voltage value of the first channel of the oscilloscope should not change;

[0033] Continue to move the cylindrical target until the signal voltage value of the oscilloscope channel 1 begins to decrease. At this time, the cylindrical target should have completely entered the detection beam range. The signal voltage value of the oscilloscope channel 1 is recorded as V1, and the signal voltage value of the oscilloscope channel 2 is recorded as V2.

[0034] S12. Use an external high-energy laser transmitter to hit the cylindrical target material on the side of the circular surface away from the detection beam, so that it moves towards the detection beam. The height of the cylindrical target material is recorded as H, and the diameter of the circular surface is recorded as D. At this time, the signal voltage waveform of the oscilloscope channel 1 is recorded as V1(t), and the signal voltage waveform of the oscilloscope channel 2 is recorded as V2(t). Then the motion trajectory X(t) of the cylindrical target material can be expressed as:

[0035]

[0036] Furthermore, the beam expander expands the detection beam projected by the laser by no less than 8 times.

[0037] Furthermore, the concave-convex lens group can expand the detection light beam projected by the laser by n times, wherein n is a positive integer greater than 1.

[0038] Beneficial effects of the present invention:

[0039] Compared with the traditional method, the technical solution solves the problem that the motion trajectory of the cylindrical target cannot be accurately measured due to the slight rotation of the cylindrical target during the movement. A circular light beam with a relatively uniform light intensity distribution is formed by combining a laser and a series of optical elements as the detection light, and a beam splitter is used at the receiving end to divide the detection light beam into two beams, which are converted into electrical signals by a photoelectric sensor after passing through a series of optical elements and received by an oscilloscope; one beam of light is used to detect the motion trajectory of the cylindrical target, and the other beam of light is used to monitor whether the cylindrical target rotates during the movement; and by analyzing and processing the two electrical signals received by the oscilloscope, the measurement error caused by the rotation of the cylindrical target can be corrected, and then the motion trajectory of the target can be obtained, thereby realizing the measurement of the motion trajectory of the cylindrical target under the action of the laser with high time resolution of nanoseconds. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The present invention will be further described below in conjunction with the accompanying drawings.

[0041] Figure 1 is an exploded view of the detection device of the present invention;

[0042] Figure 2 It is a signal voltage waveform diagram obtained by a channel of the oscilloscope in the present invention for measuring the motion trajectory of the cylindrical target material under the action of laser;

[0043] Figure 3 It is a relationship diagram of the displacement of the cylindrical target material under the action of laser without correction in the present invention versus time;

[0044] Figure 4It is a signal voltage waveform diagram obtained by the second channel of the oscilloscope in the present invention for measuring the rotation of the cylindrical target;

[0045] Figure 5 This is a relationship diagram of the displacement of the cylindrical target material under the action of the laser after correction in the present invention versus time.

[0046] In the figure: 1. Laser; 2. Beam expander; 3. Adjustable circular aperture; 4. Concave and convex lens group; 5. Beam splitter; 6. First adjustable optical slit; 7. Second adjustable optical slit; 8. First focusing lens; 9. First interference filter; 10. First photoelectric sensor; 11. Second focusing lens; 12. Second interference filter; 13. Second photoelectric sensor; 14. Oscilloscope; 15. Cylindrical target; 16. Multi-dimensional translation stage. DETAILED DESCRIPTION

[0047] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0048] Figure 1 The exploded view shows a device for detecting the trajectory of a cylindrical target under the action of a laser, wherein: Figure 1 The inserts in Fig. a and b are cross-sectional views of the detection beam at the positions indicated by the corresponding arrows, and the line of sight of the cross-sectional view is along the y-axis direction.

[0049] The detection device comprises a laser 1 for projecting a detection beam, and a beam expander 2, an adjustable circular aperture 3, a concave-convex lens group 4, a beam splitter prism 5, a first adjustable optical slit 6, a second adjustable optical slit 7, a first focusing lens 8, a first interference filter 9 and a first photoelectric sensor 10 are coaxially installed in sequence along the direction of the detection beam projected by the laser 1;

[0050] The detection device further includes a second focusing lens 11, a second interference filter 12, a second photoelectric sensor 13 and an oscilloscope 14. The second focusing lens 11, the second interference filter 12 and the second photoelectric sensor 13 are coaxially mounted on the beam splitter prism 5 in sequence, and the mounting directions of the second focusing lens 11, the second interference filter 12 and the second photoelectric sensor 13 are kept perpendicular to the direction of the detection beam projected by the laser 1.

[0051] The incident surface of the beam splitter prism 5 is perpendicular to the direction of the detection beam projected by the laser 1. After being dispersed by the beam splitter prism 5, the detection beam is emitted as two mutually perpendicular beams, wherein the projection direction of one beam is the same as the emission direction of the laser 1, and the other beam is projected toward the second focusing lens 11;

[0052] The output ends of the first photoelectric sensor 10 and the second photoelectric sensor 13 are respectively connected to the first channel and the second channel of the oscilloscope 14; a cylindrical target 15 and a multidimensional translation stage 16 are arranged between the concave-convex lens group 4 and the beam splitter prism 5, and the cylindrical target 15 is suspended above the multidimensional translation stage 16.

[0053] The device adopts a laser 1 and a series of optical elements to form a circular light beam with relatively uniform light intensity distribution as the detection light, and uses a beam splitter prism 5 at the receiving end to split the detection light beam into two beams of light, which are converted into electrical signals by two photoelectric sensors after passing through a series of optical elements respectively, and are received by an oscilloscope 14; wherein, one beam of light is used to detect the motion trajectory of the cylindrical target 15, and the other beam of light is used to monitor whether the cylindrical target 15 rotates during the motion; and by analyzing and processing the two electrical signals received by the oscilloscope 14, the measurement error caused by the rotation of the cylindrical target 15 can be corrected, and then the motion trajectory of the target can be obtained, thereby realizing the measurement of the motion trajectory of the cylindrical target 15 under the action of the laser with high time resolution of nanosecond level.

[0054] As an example, the light intensity distribution of the detection light beam projected by the laser 1 is a Gaussian distribution.

[0055] As an example, the laser power stability of the detection beam projected by the laser 1 is not less than ±2.5%.

[0056] As an example, the central wavelengths of the transmittable lights of the first interference filter 9 and the second interference filter 12 are both consistent with the wavelength of the laser 1 .

[0057] As an example, the slit centerline of the first adjustable optical slit 6, the slit centerline of the second adjustable optical slit 7, and the axis of the detection beam projected by the laser 1 together constitute a three-dimensional space, in which every two lines are perpendicular to each other. The relationship between these three lines can be understood as three coordinate axes, such as the x-axis, the y-axis, and the z-axis.

[0058] As an example, the straight line where the axial direction of the cylindrical target 15 is located is in the plane formed by the slit center line of the first adjustable optical slit 6 and the emission direction of the detection light beam projected by the laser 1 .

[0059] This scheme also proposes a method for detecting the motion trajectory of a cylindrical target under the action of a laser, which is applied to the above-mentioned detection device. The detection method includes the following steps:

[0060] S1, using a beam expander 2 to expand the detection beam projected by the laser 1, the beam expansion multiple being not less than eight times;

[0061] S2. Under the premise that no optical diffraction occurs, the adjustable circular aperture 3 is adjusted so that the diameter of the circular detection light beam passing through the adjustable circular aperture 3 is as small as possible;

[0062] S3, using the concave-convex lens group 4 to expand the laser beam passing through the adjustable circular aperture 3, so that the diameter of the circular detection beam after expansion is not less than three times the height of the cylindrical target material 15;

[0063] S4. While ensuring that the cylindrical target 15 does not block the detection beam, adjust the components so that the laser 1, the beam expander 2, the adjustable circular aperture 3, the concave-convex lens group 4, the beam splitter prism 5, the first adjustable optical slit 6, the second adjustable optical slit 7, the first focusing lens 8, the first interference filter 9 and the first photoelectric sensor 10 are coaxial and at the same height, and adjust the first adjustable optical slit 6 and the second adjustable optical slit 7 to the maximum gap;

[0064] S5. Adjust the position of the beam splitter prism 5 so that the direction of the detection beam reflected by it is perpendicular to the direction of the detection beam emitted by the laser 1. Then, place the second focusing lens 11, the second interference filter 12, and the second photoelectric sensor 13 in the direction of the reflected detection beam, and ensure that these optical elements are coaxial and at the same height as the beam splitter prism 5.

[0065] S6, by adjusting the position of the first photoelectric sensor 10, the detection light beam passing through the first focusing lens 8 is focused on the photosensitive element of the first photoelectric sensor 10, at which time the signal voltage value of a channel of the oscilloscope 14 reaches the maximum;

[0066] S7, by adjusting the position of the second photoelectric sensor 13, the laser beam passing through the second focusing lens 11 is focused on the photosensitive element of the second photoelectric sensor 13. At this time, the signal voltage value of the second channel of the oscilloscope 14 reaches the maximum, which is recorded as V 2max ;

[0067] S8, under the premise of ensuring that no optical diffraction occurs, reduce the slit width of the first adjustable optical slit 6, so that the detection beam passing through the adjustable optical slit is the thinnest. At this time, the slit centerline of the first adjustable optical slit 6 should be in the radial direction of the circular detection beam, and the slit width of the slit centerline of the first adjustable optical slit 6 should be smaller than the circular surface radius of the cylindrical target 15. At this time, the detection beam passing through the first adjustable optical slit 6 is a "straight-shaped" beam with a relatively uniform light intensity distribution. The slit width of the first adjustable optical slit 6 at this time point is recorded as S1;

[0068] S9, reduce the slit width of the second adjustable optical slit 7 until it is smaller than the height of the cylindrical target 15. At this time, the slit centerline of the second adjustable optical slit 7 should also be in the radial direction of the circular detection beam, and the slit centerline of the second adjustable optical slit 7 is perpendicular to the slit centerline of the adjustable optical slit 6. The slit width of the second adjustable optical slit at this time point is recorded as S2. At this time, the signal voltage value of a channel of the oscilloscope 14 is recorded as V 1max ;

[0069] S10, use a shield to completely block the detection beam, and record the signal voltage value of a channel of the oscilloscope 14 at this time as V 1min , remove the obstruction;

[0070] S11, by adjusting the multi-dimensional translation stage 16, the axial direction of the cylindrical target 15 is placed as far as possible in the plane formed by the slit center line of the first adjustable optical slit 6 and the direction of the detection light beam emitted by the laser 1;

[0071] Then move the cylindrical target 15 along the straight line where the cylindrical axis is located, towards the direction close to the detection beam, and observe the signal voltage value of a channel of the oscilloscope 14 at the same time. When the cylindrical target 15 begins to block the detection beam, the signal voltage value of a channel of the oscilloscope 14 should not change;

[0072] Continue to move the cylindrical target 15 until the signal voltage value of the first channel of the oscilloscope 14 begins to decrease. At this time, the cylindrical target 15 should have completely entered the detection beam range. The signal voltage value of the first channel of the oscilloscope 14 is recorded as V1, and the signal voltage value of the second channel of the oscilloscope 14 is recorded as V2.

[0073] S12. Use an external high-energy laser transmitter to strike the cylindrical target 15 on the side of the circular surface away from the detection beam, so that it moves toward the detection beam. The height of the cylindrical target 15 is recorded as H, and the diameter of the circular surface is recorded as D. At this time, the signal voltage waveform of the first channel of the oscilloscope 14 is recorded as V1(t), and the signal voltage waveform of the second channel of the oscilloscope 14 is recorded as V2(t). Then the motion trajectory X(t) of the cylindrical target 15 can be expressed as:

[0074]

[0075] As an example, the concave-convex lens group 4 can expand the detection light beam projected by the laser 1 by n times, where n is a positive integer greater than 1.

[0076] Here, an example is presented to further describe the above detection method in detail, which specifically includes the following steps:

[0077] Step 1: According to Figure 1The detection device shown in the figure builds an optical detection system, wherein the laser 1 uses a He-Ne laser (wavelength 632.8nm, spot diameter 0.8mm, light intensity distribution is Gaussian distribution, power stability is ±2.5%); the beam expander 2 uses a 10x beam expander; the concave-convex lens group 4 uses a concave-convex lens group that can expand the detection beam by 30 times; the cylindrical target 15 is a titanium target (height H=4mm, circular surface diameter D=2mm), and is suspended on a multi-dimensional translation stage 16 by a wire;

[0078] Step 2, adjusting the adjustable circular aperture 3 so that the diameter of the circular detection light beam passing through the adjustable circular aperture 3 is reduced to 0.5 mm;

[0079] Step 3, using a concave-convex lens group 4 that can expand the detection beam by 30 times, to expand the detection beam passing through the adjustable circular aperture 3, the diameter of the circular detection beam after expansion is 15 mm, which is greater than 3 times the height of the cylindrical target 15;

[0080] Step 4, while ensuring that the cylindrical target 15 does not block the detection beam, adjust each device so that the beam laser 1, the beam expander 2, the adjustable circular aperture 3, the concave-convex lens group 4, the beam splitter prism 5, the first adjustable optical slit 6, the second adjustable optical slit 7, the first focusing lens 8, the first interference filter 9 and the first photoelectric sensor 10 are coaxial and at the same height, and adjust the first adjustable optical slit 6 and the second adjustable optical slit 7 to the maximum gap;

[0081] Step 5, adjust the position of the beam splitter prism 5 so that the direction of the detection beam reflected by it is perpendicular to the emission direction of the detection beam emitted by the laser 1, and then place the second focusing lens 11, the second interference filter 12, and the second photoelectric sensor 13 in the direction of the reflected beam, and ensure that these optical elements are coaxial and at the same height as the beam splitter prism 5;

[0082] Step 6, by adjusting the position of the first photoelectric sensor 10, the detection light beam passing through the first focusing lens 8 is focused on the photosensitive element of the first photoelectric sensor 10, at which time the signal voltage value of a channel of the oscilloscope 14 reaches the maximum;

[0083] Step 7: By adjusting the position of the second photoelectric sensor 13, the detection beam passing through the second focusing lens 11 is focused on the photosensitive element of the second photoelectric sensor 13. At this time, the signal voltage value of the second channel of the oscilloscope 14 reaches the maximum, which is recorded as V 2max , read V 2max =6.20V;

[0084] Step 8: Under the premise of ensuring that no optical diffraction occurs, reduce the slit width of the first adjustable optical slit 6 so that the light beam passing through the adjustable optical slit is the thinnest. At this time, the slit centerline of the first adjustable optical slit 6 should be in the radial direction of the circular detection light beam, and its slit width should be smaller than the circular surface radius of the cylindrical target 15. In this example, the slit width S1 of the first adjustable optical slit 6 is 0.3 mm.

[0085] Step 9, reduce the slit width of the second adjustable optical slit 7 until it is slightly smaller than the height of the cylindrical target 15. At this time, the slit centerline of the second adjustable optical slit 7 should also be in the radial direction of the circular detection beam, and the slit centerline of the second adjustable optical slit 7 is perpendicular to the slit centerline of the adjustable optical slit 6. In this example, the slit width S2 of the second adjustable optical slit 7 is 3.5 mm. At this time, the signal voltage value of a channel of the oscilloscope 14 can be read, which is recorded as V 1max , at this time V 1max =1.30V;

[0086] Step 10: Use a shield to completely block the detection beam, and the signal voltage value V of a channel of the oscilloscope 14 can be read. 1min =0V, remove the obstruction;

[0087] Step 11, by adjusting the multi-dimensional translation stage 16, the axial position of the cylindrical target 15 is directly in the plane formed by the slit center line of the first adjustable optical slit 6 and the direction of the detection beam emitted by the laser 1 as much as possible; then the cylindrical target 15 is moved along the straight line where the axial direction of the cylinder is located and in the direction close to the detection beam, and the signal voltage value of the first channel of the oscilloscope 14 is observed at the same time. When the cylindrical target 15 begins to block the detection beam, the signal voltage value of the first channel of the oscilloscope 14 should not change; continue to move the cylindrical target 15 until the signal voltage value of the first channel of the oscilloscope 14 begins to decrease. At this time, the cylindrical target 15 should have completely entered the detection beam range, and the signal voltage value V1 of the first channel of the oscilloscope 14 can be read as V2 = 5.92V;

[0088] Step 12, use Nd:YAG high-energy laser to hit the circular surface of the cylindrical target 15 away from the detection beam, so that it moves towards the direction close to the detection beam, and record the signal voltage waveforms of the first channel and the second channel of the oscilloscope 14 at this time.

[0089] like Figure 2 As shown, the signal voltage waveform obtained by the first channel of the oscilloscope 14 is the measurement of the motion trajectory of the cylindrical target 15 under the action of the laser, which is recorded as V1(t), wherein the part in the dotted box is caused by the radiation light of the optical breakdown. Since the light intensity distribution of the "straight" detection beam is relatively uniform; Figure 3As shown, the relationship between the displacement of the cylindrical target 15 and time under the action of the uncorrected laser L(t) can be expressed as:

[0090]

[0091] In this example, since the Nd:YAG high-energy laser failed to focus precisely on the center of the circular surface of the cylindrical target 15, the cylindrical target 15 rotated to a certain extent while moving along the direction of the laser action. Since the suspension wire exerted a pulling force on it, the rotation of the cylindrical target 15 was a simple harmonic motion similar to attenuation. Therefore, it can be seen that Figure 3 There are obvious fluctuations in the early stage of the curve.

[0092] For the sake of Figure 3 The motion trajectory of the lower cylindrical target 15 used by the laser is corrected to obtain the kinetic energy obtained by the cylindrical target 15 in the direction of the laser action, such as Figure 4 As shown, in this example, the rotation of the cylindrical target 15 during its movement under the action of the laser is monitored synchronously, that is, the signal voltage waveform obtained by the second channel of the oscilloscope 14 is recorded as V2(t).

[0093] It can be seen that due to the rotation of the cylindrical target 15, Figure 4 There is a similar trend of oscillation in the early stage of the curve. Therefore, combining V1(t) and V2(t), the motion trajectory X(t) of the cylindrical target 15 can be expressed as:

[0094]

[0095] Thus, the error caused by rotation during the movement of the cylindrical target 15 under the action of laser is corrected, and the relationship X(t) between the displacement of the cylindrical target 15 and the time after correction can be obtained from Figure 5 Summarize and conclude in the article.

[0096] In the description of this specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0097] The above contents are merely examples and explanations of the present invention. Those skilled in the art may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the invention or exceed the scope defined by the claims, they shall all fall within the protection scope of the present invention.

Claims

1. A device for detecting the motion trajectory of a cylindrical target under the action of a laser, comprising a laser for projecting a detection beam, characterized in that: A beam expander, an adjustable circular aperture, a concave-convex lens group, a beam splitter, a first adjustable optical slit, a second adjustable optical slit, a first focusing lens, a first interference filter, and a first photoelectric sensor are coaxially installed in sequence along the direction of the detection beam projected by the laser; The detection device also includes a second focusing lens, a second interference filter, a second photoelectric sensor and an oscilloscope, wherein the second focusing lens, the second interference filter and the second photoelectric sensor are coaxially mounted on the beam splitter prism in sequence, and the mounting direction of the second focusing lens, the second interference filter and the second photoelectric sensor is perpendicular to the direction of the detection beam projected by the laser; The incident surface of the beam splitter prism is kept perpendicular to the direction of the detection beam projected by the laser. After being dispersed by the beam splitter prism, the detection beam is emitted as two mutually perpendicular beams, wherein the projection direction of one beam is the same as the emission direction of the laser, and the other beam is projected toward the second focusing lens; The output ends of the first photoelectric sensor and the second photoelectric sensor are connected to the first channel and the second channel of the oscilloscope respectively; A cylindrical target and a multi-dimensional translation stage are arranged between the concave-convex lens group and the beam splitter prism, and the cylindrical target is suspended above the multi-dimensional translation stage.

2. The device for detecting the motion trajectory of a cylindrical target under the action of laser according to claim 1 is characterized in that: The light intensity distribution of the detection light beam projected by the laser is Gaussian distribution.

3. The device for detecting the motion trajectory of a cylindrical target under the action of laser according to claim 1 is characterized in that: The laser power stability of the detection light beam projected by the laser is not less than ±2.5%.

4. The device for detecting the motion trajectory of a cylindrical target under the action of laser according to claim 1 is characterized in that: The central wavelengths of the light that can be transmitted through the first interference filter and the second interference filter are both consistent with the wavelength of the laser.

5. The device for detecting the motion trajectory of a cylindrical target under the action of laser according to claim 1, characterized in that: The slit centerline of the first adjustable optical slit, the slit centerline of the second adjustable optical slit and the axis of the detection light beam projected by the laser together constitute a three-dimensional space, in which every two lines are perpendicular to each other.

6. The device for detecting the motion trajectory of a cylindrical target under the action of laser according to claim 1, characterized in that: The straight line where the axis of the cylindrical target material is located is in a plane formed by the slit center line of the first adjustable optical slit and the emission direction of the detection light beam projected by the laser.

7. A method for detecting the motion trajectory of a cylindrical target under the action of laser, characterized in that: Applied to the detection device according to any one of claims 1 to 6, the detection method comprises the following steps: S1. Use a beam expander to expand the detection beam projected by the laser; S2. Under the premise that no optical diffraction occurs, adjust the adjustable circular aperture so that the diameter of the circular detection beam passing through the adjustable circular aperture is as small as possible; S3, using a concave-convex lens group to expand the laser beam passing through the adjustable circular aperture, so that the diameter of the circular detection beam after the expansion is not less than three times the height of the cylindrical target material; S4. While ensuring that the cylindrical target does not block the detection beam, adjust the components so that the laser, beam expander, adjustable circular aperture, concave-convex lens group, beam splitter, first adjustable optical slit, second adjustable optical slit, first focusing lens, first interference filter and first photoelectric sensor are coaxial and at the same height, and adjust the first adjustable optical slit and the second adjustable optical slit to the maximum gap; S5. Adjust the position of the beam splitter prism so that the direction of the detection beam reflected by it is perpendicular to the direction of the detection beam emitted by the laser, and then place the second focusing lens, the second interference filter, and the second photoelectric sensor in the direction of the reflected detection beam, and ensure that these optical elements are coaxial and at the same height as the beam splitter prism; S6, by adjusting the position of the first photoelectric sensor, the detection light beam passing through the first focusing lens is focused on the photosensitive element of the first photoelectric sensor, at which time the signal voltage value of a channel of the oscilloscope reaches a maximum; S7. By adjusting the position of the second photoelectric sensor, the laser beam passing through the second focusing lens is focused on the photosensitive element of the second photoelectric sensor. At this time, the signal voltage value of the second channel of the oscilloscope reaches the maximum, which is recorded as V 2max ; S8. On the premise of ensuring that no optical diffraction occurs, reduce the slit width of the first adjustable optical slit so that the detection beam passing through the adjustable optical slit is the thinnest. At this time, the slit centerline of the first adjustable optical slit should be in the radial direction of the circular detection beam, and the slit width of the slit centerline of the first adjustable optical slit should be smaller than the circular surface radius of the cylindrical target. At this time, the detection beam passing through the first adjustable optical slit is a "straight-shaped" beam with a relatively uniform light intensity distribution. The slit width of the first adjustable optical slit at this time point is recorded as S1; S9, reduce the slit width of the second adjustable optical slit until it is smaller than the height of the cylindrical target. At this time, the slit centerline of the second adjustable optical slit should also be in the radial direction of the circular detection beam, and the slit centerline of the second adjustable optical slit should remain perpendicular to the slit centerline of the adjustable optical slit. The slit width of the second adjustable optical slit at this time point is recorded as S2, and the signal voltage value of the oscilloscope channel 1 at this time is recorded as V 1max ; S10. Use a shield to completely block the detection beam, and record the signal voltage value of the oscilloscope channel 1 as V 1min , remove the obstruction; S11, by adjusting the multi-dimensional translation stage, the axial direction of the cylindrical target material is placed in the plane formed by the slit centerline of the first adjustable optical slit and the direction of the detection light beam emitted by the laser as much as possible; Then move the cylindrical target along the straight line where the cylindrical axis is located, towards the direction close to the detection beam, and observe the signal voltage value of the first channel of the oscilloscope at the same time. When the cylindrical target begins to block the detection beam, the signal voltage value of the first channel of the oscilloscope should not change; Continue to move the cylindrical target until the signal voltage value of the oscilloscope channel 1 begins to decrease. At this time, the cylindrical target should have completely entered the detection beam range. The signal voltage value of the oscilloscope channel 1 is recorded as V1, and the signal voltage value of the oscilloscope channel 2 is recorded as V2. S12. Use an external high-energy laser transmitter to hit the cylindrical target material on the side of the circular surface away from the detection beam, so that it moves towards the detection beam. The height of the cylindrical target material is recorded as H, and the diameter of the circular surface is recorded as D. At this time, the signal voltage waveform of the first channel of the oscilloscope is recorded as V1(t), and the signal voltage waveform of the second channel of the oscilloscope is recorded as V2(t). Then the motion trajectory X(t) of the cylindrical target material is expressed as:

8. The method for detecting the motion trajectory of a cylindrical target under the action of laser according to claim 7, characterized in that: The beam expander expands the detection beam projected by the laser by no less than 8 times.

9. The method for detecting the motion trajectory of a cylindrical target under the action of laser according to claim 7, characterized in that: The concave-convex lens group can expand the detection light beam projected by the laser by n times, wherein n is a positive integer greater than 1.

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