CN113834426A - Laser sail attitude measuring device based on cavendish torsion scale - Google Patents

Abstract

Translated fromChinese

本发明属于激光帆技术领域，具体为一种基于卡文迪什扭秤的激光帆姿态测量装置。本激光帆姿态测量装置真空箱、激光帆、钨丝、磁铁片、铝块、定位激光源、驱动激光源、风扇、铝架、刻度尺；其中，激光帆与钨丝一端相连接，挂在真空箱内部；磁铁片和两个铝块形成电磁阻尼，设置于激光帆两侧；驱动激光源用于向激光帆发射驱动激光，定位激光源用于向激光帆发射定位激光；钨丝的另一端固定在铝架上；刻度尺设置于激光帆的反射光路上，风扇安装在驱动激光后端，用于对驱动激光进行风冷处理。本发明可精确测量激光帆在激光光压激励下产生的偏转运动，加入电磁阻尼消除了实验中大部分噪声，具有较好的稳定性和可重复性。

The invention belongs to the technical field of laser sails, in particular to a laser sail attitude measurement device based on Cavendish torsion balance. This laser sail attitude measurement device is a vacuum box, a laser sail, a tungsten wire, a magnet sheet, an aluminum block, a positioning laser source, a driving laser source, a fan, an aluminum frame, and a scale; the laser sail is connected to one end of the tungsten wire and hangs on the Inside the vacuum box; the magnet sheet and two aluminum blocks form electromagnetic damping, which are arranged on both sides of the laser sail; the driving laser source is used to emit the driving laser to the laser sail, and the positioning laser source is used to emit the positioning laser to the laser sail; the other side of the tungsten wire One end is fixed on the aluminum frame; the scale is set on the reflected light path of the laser sail, and the fan is installed at the rear end of the driving laser for air-cooling the driving laser. The invention can accurately measure the deflection motion of the laser sail under the excitation of laser light pressure, and adding electromagnetic damping eliminates most of the noise in the experiment, and has good stability and repeatability.

Description

Laser sail attitude measuring device based on cavendish torsion scale

Technical Field

The invention belongs to the technical field of laser sails, and particularly relates to a laser sail attitude measuring device.

Background

Maxwell theoretically predicted the presence of optical pressure in the middle of the 19 th century. In the beginning of the 20 th century, the light pressure value is measured by the first experiment of the Dietzech, so that the scientific idea of driving space navigation by light pressure is initiated. In 2010, JAXA successfully launches the IKARAS laser sail to space and successfully completes various experiments, and further stimulates the enthusiasm of people for researching the laser sail spacecraft. In 2016, a 'break through shooting' Starshot plan was proposed in hokken, aiming to accelerate a laser sail to 20% of the light speed by using the huge light pressure generated by a laser array on the ground to realize interstellar navigation, target stars and sea to explore extraterrestrial civilization, search stars suitable for human living, search scarce metal resources of the earth and the like. In 2019, a research team of the american rensler has designed a prototype of such a laser sail. In contrast, the overall design of film structure spacecrafts such as laser sails and the like taking deep space exploration as missions is still in the starting stage in China. For the design scheme in the demonstration stage, the key technology of the design scheme also needs sufficient guidance and support of theoretical analysis, numerical calculation and physical or semi-physical simulation experiments. The accurate measurement of the motion attitude of the laser sail is a challenge, and directly influences the prediction and regulation of the navigation stability and other performances of the laser sail. The Kavindish torsion balance can be applied to the precise experimental measurement of various tiny physical quantities, such as universal gravitation constantGAnd coulomb's law, etc. The invention designs a laser sail attitude measurement experimental device based on a cavendish torsion scale, which can accurately measure the deflection motion of a laser sail under the excitation of laser light pressure, eliminates most noise in the experiment by adding electromagnetic damping, and has better stability and repeatability.

Disclosure of Invention

The invention aims to design a laser sail motion attitude measuring device based on a Kavindesi torsion balance with good stability and repeatability.

The invention relates to a laser sail motion attitude measuring device based on a cavendish steelyard, which is shown in figure 1 and has the following principle: after laser irradiates one side of the laser sail, the light pressure can generate a tiny torque to deflect the torsion balance system; after the positioning laser irradiates the laser sail and is reflected by the laser sail, the micro deflection can be amplified into observable light spot displacement, and the deflection angle and the displacement of the torsion balance can be calculated by measuring the light spot displacement.

The invention relates to a laser sail motion attitude measuring device based on a cavendish torsion scale, as shown in figure 1, comprising: the device comprises a vacuum box, a laser sail, a tungsten wire, a magnet piece, an aluminum block, a positioning laser source, a driving laser source, a fan, an aluminum frame and a graduated scale; wherein:

the laser sail is connected with one end of the tungsten wire through a clamp and hung in the vacuum box; the magnet pieces are adhered to the lower end of the laser sail, the two aluminum blocks are vertically arranged on two sides of the laser sail in a close range, and the magnet pieces and the two aluminum blocks form electromagnetic damping; the positioning laser and the driving laser are arranged outside the vacuum box;

the driving laser source is used for emitting driving laser to the laser sail to enable the laser sail to deflect. The area of a light spot irradiated on the laser sail is adjusted by adjusting the focal length of the driving laser source, so that the laser sail is prevented from being burnt out due to energy concentration caused by over-small irradiation area;

the positioning laser source is used for emitting positioning laser to the laser sail, and the deflection of the laser sail can be amplified after the positioning laser is reflected;

a clamping groove is designed in the vacuum box, and the aluminum frame can be stably clamped in the vacuum box through the clamping groove.

One end of the tungsten wire is connected with the laser sail, and the other end of the tungsten wire is fixed on the aluminum frame through screws and nuts. The reason for using tungsten filaments is that the raw material is readily available and the torsional stiffness of the tungsten filament is also lower, i.e. a larger deflection can be observed.

The graduated scale is arranged on a reflected light path of the laser sail at a distanceAt a distance from the laser sail ofW(ii) a After the positioning laser irradiates on the laser sail, the laser is reflected to the graduated scale and is used for amplifying the deflection of the laser sail.

And the fan is arranged at the rear end of the driving laser by using a screw nut and is used for carrying out air cooling treatment on the driving laser.

In the invention, the laser sail is preferably a square with a side length of 8-12cm (for example, a square with a side length of 10 cm).

According to the invention, the vacuum box is made of acrylic materials, so that the interference of air can be eliminated to the maximum extent by using the vacuum box, and the system error of an experiment is reduced.

In the invention, the clamp is two sheets prepared by 3D printing, the size of the clamp is 1cm x 0.5cm x 0.1cm, and the laser sail and the tungsten wire are connected through a screw nut.

In the invention, the PET aluminized film is arranged on the surface of the laser sail, and the reason for using the aluminized film is that the reflectivity is higher and is not sensitive to the laser wavelength. To provide structural support, a PET aluminum film was bonded to a forked PVC film.

In the invention, the magnet pieces on the laser sail and the aluminum blocks arranged at two sides of the laser sail form electromagnetic damping, so that disturbance caused by uneven air flow and temperature can be effectively restrained. Meanwhile, the whole system can be quickly stabilized after being subjected to micro vibration through electromagnetic damping, and the efficiency of the whole system is improved.

In the invention, the driving laser can be selected to have the wavelength of 450nm and the power of 10w, and the power of the driving laser actually irradiated on the laser sail is about 8.48w after the driving laser is partially absorbed, reflected and refracted by the acrylic vacuum box. The laser cooling mode is air cooling, and the micro vibration generated by the fan can be eliminated by cushioning a rubber pad at the lower part of the vacuum box and electromagnetic damping.

In the invention, a camera with a delayed photographing function is also adopted and placed right in front of the graduated scale to photograph the moving process of the light spots.

The invention can accurately measure the deflection motion of the laser sail under the excitation of laser light pressure, eliminates most of noise in an experiment by adding electromagnetic damping, and has better stability and repeatability.

Drawings

Fig. 1 is a schematic illustration of the device.

Figure 2 is a schematic representation of the device structure.

Fig. 3 shows the experimental result of the movement of the light spot on the scale after the laser is turned on and off, respectively.

Reference numbers in the figures: 1 is the vacuum chamber, 2 is the aluminium frame, 3 is the draw-in groove, 4 is the tungsten filament, 5 is the laser sail, 6 is the aluminium block, 7 is magnet, 8 is the drive laser source, 9 is the location laser source, 10 is the camera, 11 is the scale.

Detailed Description

The invention is further illustrated by the following examples.

Example 1:

the materials used and their parameters are as follows: the suspension wire is tungsten wire with diameterd30 μm in lengthL5.1cm, coefficient of torsionGIs 36 GPa; the laser sail is square with 10cm side length, the surface is PET aluminized film, and the reflectivity thereofRAbout 0.9, equivalent moment armlIs 3.5 cm; the vacuum box is made of acrylic materials, the size is that the outer diameter is 36cm x 36cm, the inner diameter is 30cm x 30cm, the thickness is 3cm, and the limit vacuum is-29.5 inhg; drive laser power 10w, effective PowerP8.48w, wavelength 450nm, incident angleθIs 90 degrees; positioning laser power of 20 mw; reflection distanceWIt was 144.5 cm.

The operation steps of the device are as follows:

(1) the distance between the aluminum block and the magnet is adjusted, so that the vibration of the laser sail can be well inhibited, and the deflection of the laser sail cannot be influenced. The vacuum box was closed and vacuum was drawn using a vacuum pump.

(2) And starting the driving laser to confirm that the irradiation area of the driving laser is large enough and the laser sail cannot be burnt. And after the completion, closing the driving laser, adjusting the position of the camera, and finishing the preparation work.

(3) The driving laser is started and irradiates the left end of the laser sail, so that the displacement of the light spot emitted by the graduated scale can be observed, the laser sail deflects, and the light spot returns to the initial position after the driving laser is turned off.

(4) And (4) after repeating the step (3) for 3 times, adjusting the irradiation position of the driving laser to irradiate the laser sail at the right end of the laser sail, observing that the light spot on the graduated scale moves in the opposite direction at the moment, closing the driving laser, returning the light spot to the initial position, and finishing the experiment after repeating the step (3) for 3 times.

(5) The experimental video was processed into an experimental data map, as shown in fig. 3, with an experimental measurement of about 8.69 cm.

(6) The theoretical value is calculated by the formula

Wherein

. In the formulaWIn order to be the reflection distance,Pin order to drive the effective power of the laser,Rin order to be the reflectivity of the laser sail,θin order to drive the laser light at an angle of incidence,lis an equivalent force arm,cin order to be the speed of light,Gis the torsion coefficient of the tungsten filament and is,dthe diameter of the tungsten wire is the diameter of the tungsten wire,Lis the length of the tungsten filament. The theoretical calculation result is 9.68 cm, which is similar to the experimental measurement value, and the error is 10.2%.

Example 2:

the suspension wire is tungsten wire with diameterd30 μm in lengthL12.0cm, coefficient of torsionGIs 36 GPa; the laser sail is square with 10cm side length, the surface is PET aluminized film, and the reflectivity thereofRAbout 0.9, equivalent moment armlIs 4.0 cm; the vacuum box is made of acrylic materials, the size is that the outer diameter is 36cm x 36cm, the inner diameter is 30cm x 30cm, the thickness is 3cm, and the limit vacuum is-29.5 inhg; laser power 10w, effective powerP8.48w, wavelength 450nm, incident angleθIs 90 degrees; positioning laser power of 20 mw; reflection distanceWIs 284.5 cm.

The procedure of example 1 was repeated to obtain an experimental spot deviation of about 44.8cm, a theoretical spot deviation of 51.3cm, and a deviation of 12.7%.

Claims (6)

Translated fromChinese

1.一种基于卡文迪什扭秤的激光帆姿态测量装置，其特征在于，包括：真空箱、激光帆、钨丝、磁铁片、铝块、定位激光源、驱动激光源、风扇、铝架、刻度尺；其中：1. a laser sail attitude measuring device based on Cavendish torsion balance, is characterized in that, comprises: vacuum box, laser sail, tungsten wire, magnet sheet, aluminum block, positioning laser source, driving laser source, fan, aluminum racks, scales; of which:所述激光帆通过夹具与钨丝的一端相连接，并挂在真空箱内部；所述磁铁片粘贴在激光帆下端，所述铝块为两个，垂直设置于激光帆近距离两侧，磁铁片和两个铝块形成电磁阻尼；所述定位激光及驱动激光设置于真空箱外部；The laser sail is connected with one end of the tungsten wire through a clamp and hangs inside the vacuum box; the magnet sheet is pasted on the lower end of the laser sail, and there are two aluminum blocks, which are vertically arranged on both sides of the laser sail at a short distance. The sheet and two aluminum blocks form electromagnetic damping; the positioning laser and the driving laser are arranged outside the vacuum box;所述驱动激光源用于向激光帆发射驱动激光，使激光帆发生偏转；The driving laser source is used for emitting driving laser to the laser sail to deflect the laser sail;通过调整驱动激光源的焦距来调节照射在激光帆上的光斑的面积，避免照射面积过小导致能量集中烧毁激光帆；Adjust the area of the light spot irradiated on the laser sail by adjusting the focal length of the driving laser source, so as to prevent the laser sail from being burnt due to concentrated energy due to too small irradiation area;所述定位激光源用于向激光帆发射定位激光，经反射后可放大激光帆的偏转；The positioning laser source is used to emit the positioning laser to the laser sail, which can amplify the deflection of the laser sail after being reflected;所述真空箱内部设计有一个卡槽，所述铝架通过卡槽卡在真空箱内部；A card slot is designed inside the vacuum box, and the aluminum frame is locked inside the vacuum box through the card slot;所述钨丝的一端与激光帆连接，另一端通过螺丝螺母固定在所述铝架上；One end of the tungsten wire is connected with the laser sail, and the other end is fixed on the aluminum frame by screws and nuts;所述刻度尺设置于激光帆的反射光路上，距离激光帆的距离为W；当定位激光照射在激光帆上后，激光被反射到刻度尺上，用于放大激光帆的偏转；The scale is arranged on the reflected light path of the laser sail, and the distance from the laser sail isW ; when the positioning laser is irradiated on the laser sail, the laser is reflected on the scale for amplifying the deflection of the laser sail;所述风扇安装在驱动激光后端 ，用于对驱动激光进行风冷处理。The fan is installed at the rear end of the driving laser, and is used for air-cooling the driving laser.2.根据权利要求1所述的基于卡文迪什扭秤的激光帆姿态测量装置，其特征在于，所述驱动激光源,通过调整驱焦距来调节照射在激光帆上的光斑的面积，避免照射面积过小导致能量集中烧毁激光帆。2. The laser sail attitude measurement device based on Cavendish torsion balance according to claim 1, wherein the drive laser source adjusts the area of the light spot irradiated on the laser sail by adjusting the drive focal length to avoid If the irradiation area is too small, the concentrated energy will burn the laser sail.3.根据权利要求1所述的基于卡文迪什扭秤的激光帆姿态测量装置，其特征在于，所述激光帆为边长8-12cm的正方形。3 . The laser sail attitude measurement device based on Cavendish torsion balance according to claim 1 , wherein the laser sail is a square with a side length of 8-12 cm. 4 .4.根据权利要求1所述的基于卡文迪什扭秤的激光帆姿态测量装置，其特征在于，所述激光帆表面有PET镀铝膜。4 . The laser sail attitude measurement device based on Cavendish torsion balance according to claim 1 , wherein the laser sail has a PET aluminized film on the surface. 5 .5.根据权利要求1所述的基于卡文迪什扭秤的激光帆姿态测量装置，其特征在于，所述驱动激光，其波长为450nm，功率为10w。5 . The laser sail attitude measurement device based on Cavendish torsion balance according to claim 1 , wherein the driving laser has a wavelength of 450 nm and a power of 10 W. 6 .6.根据权利要求1所述的基于卡文迪什扭秤的激光帆姿态测量装置，其特征在于，刻度尺正前方放置具有延迟摄影功能的相机，用于将光斑移动的过程拍摄下来。6 . The laser sail attitude measurement device based on Cavendish torsion balance according to claim 1 , wherein a camera with a delay photography function is placed in front of the scale to photograph the process of moving the light spot. 7 .

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