1. A laser ablation driven two dimensional momentum measurement device for irregular targets, comprising: the device comprises a laser emitting device (1) for emitting laser, a focusing lens (2) for focusing the laser, a target fixing tool (3) for placing a target sample, a suspension device for suspending the target fixing tool (3), a first displacement measuring device (4) arranged along the axis direction of the laser emission and a second displacement measuring device (5) arranged perpendicular to the axis direction of the laser emission;

the laser emitting device (1), the focusing lens (2) and the target fixing tool (3) are sequentially and transversely arranged along the same horizontal line; the target fixing tool (3) can freely swing under the action of impulse generated by laser ablation of the target sample; the first displacement measuring device (4) and the second displacement measuring device (5) are located on the same horizontal plane and are respectively used for measuring the swinging amount of the target fixing tool (3) in the direction of the first displacement measuring device and the second displacement measuring device.

2. The laser ablation driven irregular target two-dimensional impulse measuring device according to claim 1, characterized in that the target fixing tool (3) is a hollow cube structure; the target fixing tool (3) faces one side of the focusing lens (2) and is provided with a placing opening.

3. The laser ablation driven irregular target two-dimensional impulse measuring device of claim 1, characterized in that the suspension device comprises a hoisting bracket (6) and four suspension ropes (7) of equal length; the four suspension ropes (7) are respectively and fixedly connected to four corners of the top of the target fixing tool (3), and the free ends of the four suspension ropes (7) are fixed to the same point on the hoisting support (6).

4. The laser ablation driven irregular target two-dimensional impulse measuring device according to claim 2, characterized in that the outer surfaces of the three sides of the target fixing tool (3) without the placing opening are respectively smooth and flat.

5. The laser ablation driven irregular target two-dimensional impulse measurement device of claim 1, characterized in that the first displacement measurement device (4) and the second displacement measurement device (5) are laser displacement sensors, respectively.

6. A laser ablation driven irregular target two-dimensional impulse measurement method using the laser ablation driven irregular target two-dimensional impulse measurement device of any one of claims 1-5, the method comprising the steps of:

acquiring the maximum swinging amount dx of the target fixing tool in a first direction and the maximum swinging amount dy in a second direction through the first displacement measuring device and the second displacement measuring device;

calculating an impulse value Ix of the target sample in the first direction by adopting an impulse calculation algorithm according to the maximum oscillating quantity dx of the target fixing tool in the first direction;

and calculating the impulse value Iy of the target sample in the second direction by adopting an impulse calculation algorithm according to the maximum oscillating quantity dy of the target fixing tool in the second direction.

7. The laser ablation driven irregular target two-dimensional impulse measurement method according to claim 6, wherein the method for calculating the impulse value I of the target sample in a certain direction by adopting an impulse calculation algorithm according to the maximum oscillation d of the target fixing tool in the certain direction comprises the following steps:

calculating the swing angle theta of the target fixing tool along the direction:

θ＝arcsin(d/L)；

calculating the height change h of the target fixing tool in the vertical direction:

h＝L(1-cosθ)＝L(1-cos(arcsin(d/L)))；

according to the law of conservation of mechanical energy, calculating the speed v of the target fixing tool:

according to the momentum theorem, calculating the impulse I of the target sample in the direction:

wherein g is the acceleration of gravity; m is the total mass of the target sample and the target fixing tool; l is the suspension height of the target fixing tool; d is the maximum swing amount of the target fixing tool in a certain direction.

Background

The laser ablation driving technology is widely applied to the fields of laser propulsion, space debris removal and ultra-high-speed emission. The application of this technique relies on studies describing the law of generation of the impulse of interaction between laser and substance. Currently, research in this field drives micro-impulse measurement systems mainly by laser ablation. The existing measuring system can only measure one-dimensional impulse size, so that the expected impulse direction of the plane or regular-shaped target with known expected impulse direction can only be on the measuring axis of the measuring system. However, in the fields of space debris removal by laser ablation driving, asteroid defense by laser ablation driving deflection and the like, most targets with laser ablation driving effects are irregular-shaped targets, and the impulse direction of the targets cannot be predicted before impulse measurement is carried out on the targets, so that the impulse perpendicular to the measurement axis cannot be measured when the traditional one-dimensional measurement system is used for measurement, the experimental result is deviated, and the impulse condition of the targets obtained under the action of laser cannot be truly reflected. Therefore, the application provides a laser ablation driving irregular target two-dimensional impulse measuring device and method.

Disclosure of Invention

The invention aims to solve the problems and provides a laser ablation driving irregular target two-dimensional impulse measuring device and method.

In a first aspect, the present application provides a laser ablation driven irregular target two-dimensional impulse measurement device, including: the device comprises a laser emitting device for emitting laser, a focusing lens for focusing the laser, a target fixing tool for placing a target sample, a suspension device for suspending the target fixing tool, a first displacement measuring device arranged along the axis direction of the laser emission and a second displacement measuring device arranged perpendicular to the axis direction of the laser emission;

the laser emitting device, the focusing lens and the target fixing tool are sequentially and transversely arranged along the same horizontal line; the target fixing tool can freely swing under the action of impulse generated by laser ablation of the target sample; the first displacement measuring device and the second displacement measuring device are located on the same horizontal plane and are respectively used for measuring the swinging amount of the target fixing tool in the direction of the first displacement measuring device and the second displacement measuring device.

According to the technical scheme provided by some embodiments of the application, the target fixing tool is of a hollow cube structure; the target fixing tool faces one side of the focusing lens and is provided with a placing opening.

According to the technical scheme provided by some embodiments of the application, the suspension device comprises a hoisting bracket and four suspension ropes with equal length; the four suspension ropes are respectively and fixedly connected to four corners of the top of the target fixing tool, and the free ends of the four suspension ropes are fixed to the same point on the hoisting support.

According to the technical scheme provided by some embodiments of the application, the outer surfaces of the three sides of the target fixing tool without the placing opening are respectively smooth and flat.

According to the technical scheme provided by some embodiments of the present application, the first displacement measuring device and the second displacement measuring device are laser displacement sensors respectively.

In a second aspect, the present application provides a laser ablation driven irregular target two-dimensional impulse measurement method using the laser ablation driven irregular target two-dimensional impulse measurement device as described above, the method comprising the steps of:

acquiring the maximum swinging amount dx of the target fixing tool in a first direction and the maximum swinging amount dy in a second direction through the first displacement measuring device and the second displacement measuring device;

calculating an impulse value Ix of the target sample in the first direction by adopting an impulse calculation algorithm according to the maximum oscillating quantity dx of the target fixing tool in the first direction;

and calculating the impulse value Iy of the target sample in the second direction by adopting an impulse calculation algorithm according to the maximum oscillating quantity dy of the target fixing tool in the second direction.

According to the technical scheme provided by some embodiments of the present application, the method for calculating the impulse value I of the target sample in a certain direction by using an impulse calculation algorithm according to the maximum oscillation d of the target fixing tool in the certain direction comprises:

calculating the swing angle theta of the target fixing tool along the direction:

θ＝arcsin(d/L)；

calculating the height change h of the target fixing tool in the vertical direction:

h＝L(1-cosθ)＝L(1-cos(arcsin(d/L)))；

according to the law of conservation of mechanical energy, calculating the speed v of the target fixing tool:

according to the momentum theorem, calculating the impulse I of the target sample in the direction:

wherein g is the acceleration of gravity; m is the total mass of the target sample and the target fixing tool; l is the suspension height of the target fixing tool; d is the maximum swing amount of the target fixing tool in a certain direction.

Compared with the prior art, the beneficial effect of this application: the laser ablation driving irregular target two-dimensional impulse measuring device is characterized in that a laser emitting device, a focusing lens and a target fixing tool are sequentially arranged along the same horizontal line, and the target fixing tool is suspended on a suspension device, so that a target sample placed in the target fixing tool can freely swing under the action of impulse generated by laser ablation of the target sample to generate displacement; the first displacement measuring device is arranged along the axis direction of laser emission, and the second displacement measuring device is arranged along the axis direction perpendicular to the laser emission, so that when the target fixing tool swings freely, the displacement of the target fixing tool in the laser action direction and the displacement perpendicular to the laser action direction can be measured in real time, the impulse obtained by the target fixing tool in the two directions can be calculated, and the two-dimensional impulse of the target sample under the action of laser ablation driving can be obtained.

Drawings

Fig. 1 is a schematic structural diagram of a laser ablation driven irregular target two-dimensional impulse measurement device provided in embodiment 1 of the present application;

fig. 2 is a schematic structural diagram of a suspension device for driving an irregular target two-dimensional impulse measuring device through laser ablation provided in embodiment 1 of the present application;

fig. 3 is a test schematic diagram of a laser ablation-driven irregular target two-dimensional impulse measurement method provided in embodiment 2 of the present application.

The text labels in the figures are represented as:

1. a laser emitting device; 2. a focusing lens; 3. fixing a target; 4. a first displacement measuring device; 5. a second displacement measuring device; 6. hoisting a support; 7. a suspension rope.

Detailed Description

The following detailed description of the present application is given for the purpose of enabling those skilled in the art to better understand the technical solutions of the present application, and the description in this section is only exemplary and explanatory, and should not be taken as limiting the scope of the present application in any way.

Example 1

Referring to fig. 1, the present embodiment provides a two-dimensional impulse measurement device for driving an irregular target by laser ablation, including: the device comprises a laser emitting device 1 for emitting laser, a focusing lens 2 for focusing the laser, a target fixing tool 3 for placing a target sample, a suspension device for suspending the target fixing tool 3, a first displacement measuring device 4 arranged along the axis direction of the laser emission, and a second displacement measuring device 5 arranged perpendicular to the axis direction of the laser emission.

The laser emitting device 1, the focusing lens 2 and the target fixing tool 3 are sequentially and transversely arranged along the same horizontal line; as shown in fig. 1, the axis direction of laser emission is set to the x direction, and the axis direction perpendicular to the laser emission is set to the y direction; the laser emitting device 1, the focusing lens 2 and the target fixing tool 3 are sequentially arranged along the positive direction of an x axis; the laser emitted by the laser emitting device 1 is focused by the focusing lens 2 and then is irradiated on a target sample in the target fixing tool 3; the target fixing tool 3 can freely swing under the action of impulse generated by laser ablation of the target sample; the first displacement measuring device 4 and the second displacement measuring device 5 are located on the same horizontal plane, as shown in fig. 1, the first displacement measuring device 4 is disposed on the x-axis and located on one side of the target fixing tool 3 away from the focusing lens 2; the second displacement measuring device 5 is arranged on the y-axis; the first displacement measuring device 4 and the second displacement measuring device 5 are respectively used for measuring the swing amount of the target fixing tool 3 in the x-axis direction and the y-axis direction.

Further, the target fixing tool 3 is a hollow cube structure; a placing opening is formed in one side, facing the focusing lens 2, of the target fixing tool 3; the placing port is used for placing a target sample into the target fixing tool 3 and also provides an irradiation inlet for focused laser.

With further reference to fig. 2, the suspension device includes a hoisting bracket 6 and four suspension ropes 7 with equal length; the hoisting bracket 6 comprises an upright column arranged perpendicular to the horizontal plane and a cross column vertically arranged at the top of the upright column; the four suspension ropes 7 are respectively and fixedly connected to four corners of the top of the target fixing tool 3, and the free ends of the four suspension ropes 7 are fixed to the same point on the cross column of the hoisting bracket 6; the method of suspending the target fixing tool 3 by using the rope system composed of the four suspension ropes 7 enables the target fixing tool 3 to swing freely in all directions and not to rotate easily when laser ablation drive test is performed.

Further, the target fixing tool 3 of a cube structure has a top surface, a bottom surface and four side surfaces, wherein the side surface facing the focusing lens 2 is the side surface having the placing opening, and the outer surfaces of the other three side surfaces are smooth and clean planes respectively, so as to facilitate displacement measurement of the first displacement measuring device 4 and the second displacement measuring device 5.

Further, the first displacement measuring device 4 and the second displacement measuring device 5 are laser displacement sensors respectively; the first displacement measuring device 4 and the second displacement measuring device 5 are respectively connected with a controller; the controller is used for transmitting the measured data to the controller, and the controller calculates the impulse in the corresponding direction according to the received displacement measurement data.

When the device for measuring the two-dimensional impulse of the irregular target driven by laser ablation provided by the embodiment is used, a target sample is placed in the target fixing tool 3, the laser emitting device 1 is controlled to emit laser, the emitted laser passes through the focusing lens 2 and then is focused on the target sample, and plasma plume is generated by ablating the surface of the target sample, namely, driving impulse is generated, so that the target fixing tool 3 drives the four suspension ropes 7 to swing freely under the action of the impulse, and displacement is generated in the directions of an x axis and a y axis; the displacement change processes of the target fixing tool 3 in the x-axis direction and the y-axis direction are respectively recorded through the first displacement measuring device 4 and the second displacement measuring device 5, the maximum offset distance of the target fixing tool in the x-axis direction and the maximum offset distance of the target fixing tool in the y-axis direction are selected, and finally, the impulse in the x-axis direction and the impulse in the y-axis direction are calculated.

According to the laser ablation drive irregular target two-dimensional impulse measuring device provided by the embodiment, the laser emitting device, the focusing lens and the target fixing tool are sequentially arranged along the same horizontal line, and the target fixing tool is suspended on the suspension device, so that a target sample placed in the target fixing tool can freely swing to generate displacement under the action of impulse generated by laser ablation of the target sample; the first displacement measuring device is arranged along the axis direction of laser emission, and the second displacement measuring device is arranged along the axis direction perpendicular to the laser emission, so that when the target fixing tool swings freely, the displacement of the target fixing tool in the laser action direction and the displacement perpendicular to the laser action direction can be measured in real time, the impulse obtained by the target fixing tool in the two directions can be calculated, and the two-dimensional impulse of the target sample under the action of laser ablation driving can be obtained.

Example 2

The embodiment provides a method for measuring two-dimensional impulse of an irregular target driven by laser ablation, which adopts the device for measuring two-dimensional impulse of an irregular target driven by laser ablation described in embodiment 1, and the method includes the following steps:

acquiring the total mass of a target sample and a target fixing tool, and recording the total mass as m;

acquiring the suspension height of the target fixing tool, and recording the suspension height as L;

starting the test: controlling a laser emitting device to emit laser, and focusing the laser on a target sample after passing through a focusing lens to generate a driving impulse so as to enable a target fixing tool to swing freely;

recording displacement changes of the target fixing tool in a first direction (namely, an x-axis direction) and a second direction (namely, a y-axis direction) in real time through the first displacement measuring device and the second displacement measuring device, and acquiring a maximum swinging amount dx of the target fixing tool in the x-axis direction and a maximum swinging amount dy of the target fixing tool in the y-axis direction;

calculating the impulse value Ix of the target sample in the x-axis direction by adopting an impulse calculation algorithm according to the maximum oscillating quantity dx of the target fixing tool in the x-axis direction;

and calculating the impulse value Iy of the target sample in the y-axis direction by adopting an impulse calculation algorithm according to the maximum oscillation dy of the target fixing tool in the y-axis direction.

Next, the calculation process of the impulse calculation algorithm will be specifically described.

Referring to fig. 3, if the maximum swing amount d of the target fixing tool in a certain direction is set, the method for calculating the impulse value I of the target sample in the certain direction by using the impulse calculation algorithm according to the maximum swing amount d of the target fixing tool in the certain direction includes:

(1) calculating a swing angle theta of the target fixing tool along the direction, and obtaining the following result according to a sine formula sin theta which is d/L:

θ＝arcsin(d/L)；

(2) calculating the height change h of the target fixing tool in the vertical direction, and obtaining the height change h according to a cosine formula cos θ ═ L-h)/L:

h＝L(1-cosθ)＝L(1-cos(arcsin(d/L)))；

(3) according to the law of conservation of mechanical energy, only in the case of acting by gravity (or the elastic force of a spring), the gravitational potential energy (or the elastic potential energy) and the kinetic energy of the object are mutually converted, but the total mechanical energy is kept unchanged, i.e. the total mechanical energy is constantObtaining the speed v of the target fixing tool:

(4) according to the law of momentum, the momentum change of an object at the beginning and end of a process is equal to the impulse of the force it is subjected to during the process, the impulse of the target sample in that direction I:

wherein g is the acceleration of gravity; m is the total mass of the target sample and the target fixing tool; l is the suspension height of the target fixing tool; d is the maximum swing amount of the target fixing tool in a certain direction.

Substituting the maximum swinging amount dx of the target fixing tool in the x-axis direction into the impulse calculation formula to obtain the impulse value Ix of the target sample in the x-axis direction, namely

Substituting the maximum swinging amount dy of the target fixing tool in the y-axis direction into the impulse calculation formula to obtain the impulse value Iy of the target sample in the y-axis direction, namely

The principles and embodiments of the present application are explained herein using specific examples, which are provided only to help understand the method and the core idea of the present application. The foregoing is only a preferred embodiment of the present application, and it should be noted that there are no specific structures which are objectively limitless due to the limited character expressions, and it will be apparent to those skilled in the art that a plurality of modifications, decorations or changes can be made without departing from the principle of the present invention, and the technical features mentioned above can be combined in a suitable manner; such modifications, variations, combinations, or adaptations of the invention in other instances, which may or may not be practiced, are intended to be within the scope of the present application.