CN111538100A - Posture adjusting device and method for cold atom interference type gravity meter probe - Google Patents
Posture adjusting device and method for cold atom interference type gravity meter probe Download PDFInfo
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Abstract
The invention discloses an attitude adjusting device and method for a cold atom interference type gravity meter probe, and relates to the field of cold atom interference precision measurement. The device is as follows: the supporting surface is provided with a supporting plate, 3 electric supporting legs or 2 electric supporting legs and 1 common supporting leg; the supporting plate is provided with a probe, and the inclinometer is arranged on the probe or the supporting plate; the electric supporting leg, the circuit and the computer are sequentially connected; the inclinometer is connected with the computer. The method comprises the following steps: the calibration process includes: A. changing the posture of the probe point by point; B. recording inclination angle data and simultaneously recording probe output; C. fitting; the adjusting process comprises the following steps: a. placing a probe; b. reading the inclination angle; a PID algorithm; d. the electric supporting leg stretches out and draws back; e. the tilt value is equal to the calibrated tilt value. The invention can quickly and automatically adjust the posture of the gravity instrument probe, so that the direction of the operating laser wave vector is parallel to the gravity direction; enough data points can be obtained, the calibration inclination angle value can be accurately determined, and the system error of the gravimeter is reduced.
Description
Technical Field
The invention relates to the field of cold atom interference precision measurement, in particular to an attitude adjusting device and method for a cold atom interference type gravity meter probe.
Background
Gravity measurement has important application in the fields of geophysics, geodesic, metrology, inertial navigation, resource exploration and the like; the cold atom interference type gravimeter is a novel high-precision absolute gravimeter. The cold atom interference type gravimeter takes cold atomic groups as a test substance, and utilizes laser phases as scales to record atomic positions, so that the gravity acceleration is measured with high precision. The gravity checking material is a cold atomic group rather than a macroscopic object, so that no mechanical abrasion is generated in the working process, and the gravity can be continuously measured for a long time, which is an advantage that the traditional high-precision absolute gravimeter (FG5 gravimeter) does not have.
Cold atom interference gravimeters are based on atom interference technology, which uses laser to split, reflect and combine cold atomic groups, so that atoms interfere like light. In the cold atom interference type gravimeter, the angle between the direction of the operating laser wave vector and the gravity direction is an important factor influencing the gravity measurement accuracy. If the included angle between two straight lines along the wave vector direction of the operating laser and the gravity direction is theta, the gravity measurement deviation caused by the included angle theta of 1mrad can reach 500 mu Gal (1 mu Gal is 10)-8m/s2≈10-9g). In high-precision gravity measurement, this is a large systematic error. The operation laser wave vector direction is directly related to the posture of the gravity meter probe, and the operation laser wave vector direction can be changed by adjusting the posture of the gravity meter probe, so that the operation laser wave vector direction is parallel to the gravity direction (namely the included angle theta approaches to 0), and the system error caused by the included angle theta is restrained.
At present, the method for adjusting the posture of a cold atom interference type gravity meter probe and inhibiting the system error caused by an included angle theta mainly comprises the following 3 methods:
1. manually adjusting the posture of the gravity meter probe, recording the inclination angle value of the gravity meter probe by using an inclinometer, and recording the gravity acceleration (or the phase value of the interference fringe) output by the gravity meter. Fitting a relation between the inclination angle value and the gravity acceleration (or the interference fringe phase value), determining a calibration inclination angle value when the operating laser wave vector direction is parallel to the gravity direction, and then adjusting the inclination angle of the gravimeter probe to the calibration inclination angle value (ArnaudLandagin, et al-9g with a transportable absolute quantum gravimeter.Scientific Reports,2018,8:12300)。
2. Manually adjusting the posture of a probe of the gravimeter, recording the inclination angle value of the probe of the gravimeter by using an inclinometer, recording the gravity acceleration (or the phase value of interference fringes) output by the gravimeter, and fitting a relational expression between the inclination angle and the gravity acceleration (or the phase value of the interference fringes); and then, the inclination angle of the gravity meter probe is monitored in real time, and the system error caused by the included angle theta is compensated. (Holger Muller, et al, gradient users using a mobile atom interferometer, science Advance,2019,5: eaax 0800; Qiang Lin, et al, A new type of compact mapper for long-term absorption sensitivity monitoring. Metalogia, 2019,56: 025001).
3. The posture of the gravimeter probe is adjusted in real time by adopting a gyro stabilization platform, so that the direction of the operating laser wave vector is parallel to the gravity direction (A.Bresson, et al. Absolute white gravity with a signal-wave interaction.
The method can adjust the posture of the cold atom interference type gravity meter probe and inhibit the system error caused by the included angle theta, but the method still has the following problems:
firstly, in the methods 1 and 2, the posture of the gravity meter probe needs to be manually adjusted for many times, the adjustment process is time-consuming and labor-consuming, and the manual adjustment precision is low.
Secondly, the method 3 adopts a gyro stabilizing platform to adjust the posture of the gravity meter probe in real time, but the method has great limitation on the size and the weight of the gravity meter probe, and the gyro stabilizing platform is complex and expensive.
Disclosure of Invention
The invention aims to overcome the defects and shortcomings of the prior art and provides a posture adjusting device and method for a cold atom interference type gravimeter probe, which can quickly and automatically adjust the posture of the gravimeter probe so that the direction of an operating laser wave vector is parallel to the gravity direction.
The object of the invention is achieved by:
attitude adjusting device (device for short) for cold atom interference type gravity meter probe
The device comprises a probe, an inclinometer, an electric supporting leg, a common supporting leg, a supporting plate, a supporting surface, a circuit and a computer;
the connection relation is as follows:
1 supporting plate, 3 electric supporting feet or 2 electric supporting feet and 1 common supporting foot are arranged on the supporting surface; the supporting plate is provided with a probe, and the inclinometer is arranged on the probe or the supporting plate; the electric supporting leg, the circuit and the computer are sequentially connected; the inclinometer is connected with the computer.
Second, posture adjustment method (method for short) for cold atom interference type gravity meter probe
The cold atom interference type gravity meter probe posture adjusting device has the main function of carrying out posture adjustment on the cold atom interference type gravity meter probe, so that the cold atom interference type gravity meter operation laser wave vector direction is parallel to the gravity direction, and the gravity measurement system error is reduced to the maximum extent.
The method includes a calibration process and an adjustment process.
The calibration process includes:
A. changing the posture of the probe point by point;
B. recording inclination angle data and simultaneously recording probe output;
C. fitting;
the adjusting process comprises the following steps:
a. placing a probe;
b. reading the inclination angle;
a PID algorithm;
d. the electric supporting leg stretches out and draws back;
e. the tilt value is equal to the calibrated tilt value.
Compared with the prior art, the invention has the following advantages and positive effects:
firstly, the invention can quickly and automatically adjust the posture of the gravity instrument probe, so that the direction of the operating laser wave vector is parallel to the gravity direction;
secondly, the posture adjusting device is simple in structure and low in overall cost;
the motor is a stepping motor, and a harmonic speed reduction mode is adopted, so that the torque is large, the installation size is small, the power consumption is low, and the vibration noise is low;
the electric telescopic rod of the electric supporting leg has long stroke and high thread density, and can realize large-range high-precision inclination angle adjustment;
by adopting the attitude adjusting device and the method thereof, enough data points can be obtained, the calibration inclination angle value can be accurately determined, and the system error of the gravimeter is reduced.
Drawings
FIG. 1 is a schematic structural view of the apparatus;
FIG. 2 is a schematic structural view of the probe 1;
fig. 3 is a schematic structural view of the electric supporting foot 3;
fig. 4 is a schematic structural view of a common supporting foot 4;
FIG. 5 is a diagram of the steps of the method;
FIG. 6 is a schematic of data points and fitted curves according to the present invention.
Wherein:
1-a probe;
1-a reflector, wherein,
1-2-a vacuum cavity,
1-3-a bias magnetic field coil,
1-4-a microwave emitter,
1-5-an anti-Helmholtz coil,
1-6-1 st laser transmitter,
1-7-2 nd laser transmitter,
1-8-a photo-detector,
1-9-a source of atoms,
1-10-magnetic shield;
2-inclinometer;
3-an electric supporting foot,
3-1-a fixed sleeve,
3-1-a limiting hole,
3-2-a bearing, wherein the bearing is provided with a bearing,
3-3, an electric telescopic rod,
3-4-the 1 st support block,
3-5-the motor is driven by the motor,
3-5-1-motor rotating shaft,
3-6-coupling means;
4-common supporting feet;
4-1-a telescopic rod, wherein,
4-2-a threaded sleeve,
4-3-2 nd support block;
5, a support plate;
6-a support surface;
7-a circuit;
8, a computer.
Detailed Description
The following detailed description is made with reference to the accompanying drawings and examples:
first, posture adjusting device (device for short)
1. The method comprises the following steps:
as shown in fig. 1, the device comprises a probe 1, an inclinometer 2, an electric supporting leg 3, a common supporting leg 4, a supporting plate 5, a supporting surface 6, a circuit 7 and a computer 8;
the connection relation is as follows:
1 supporting plate 5, 3 electric supporting legs 3 or 2 electric supporting legs 3 and 1 common supporting leg 4 are arranged on the supporting surface 6; a probe 1 is arranged on the supporting plate 5, and an inclinometer 2 is arranged on the probe 1 or the supporting plate 5; the electric supporting leg 3, the circuit 7 and the computer 8 are connected in sequence; the inclinometer 2 is connected with the computer 8.
The working mechanism is as follows:
in the device, a probe 1 is fixed on a support plate 5, and the support plate 5 is supported by 3 electric support legs 3 or 2 electric support legs 3 and 1 common support leg 4; the computer 8 can control the extension and contraction of the electric supporting legs 3 through the circuit 7; when the electric supporting legs 3 extend and contract, the inclination angles of the supporting plate 5 and the probe 1 fixed on the supporting plate 5 on the horizontal plane correspondingly change; the inclinometer 2 is used for monitoring the inclination angle of the probe 1 on the horizontal plane, and the inclination angle can reflect the posture of the probe 1.
2. Functional unit
1) Probe 1
The probe 1 is a cold atom interference type gravimeter probe, which can output the acceleration of gravity and the phase of the atomic interference fringes.
Referring to FIG. 2, the probe 1 comprises a reflector 1-1, a vacuum chamber 1-2, a bias magnetic field coil 1-3, a microwave emitter 1-4, an anti-Helmholtz coil 1-5, a 1 st laser emitter 1-6, a 2 nd laser emitter 1-7, a photoelectric detector 1-8, an atom source 1-9 and a magnetic shielding cover 1-10.
The position and connection relation is as follows:
a reflector 1-1, a vacuum cavity 1-2 and a 2 nd laser emitter 1-7 are sequentially arranged in the magnetic shield 1-10 from top to bottom;
a bias magnetic field coil 1-3 is arranged at the upper part of the vacuum cavity 1-2 in a surrounding way;
the left side and the right side of the middle part of the vacuum cavity 1-2 are respectively provided with a microwave emitter 1-4 and a photoelectric detector 1-8;
an anti-Helmholtz coil 1-5, 6 first laser transmitters 1-6 which are spatially symmetrical and an atom source 1-9 are arranged at the lower part of the vacuum cavity 1-2; the anti-Helmholtz coil 1-5 surrounds the lower part of the vacuum cavity 1-2, 3 pairs of mutually vertical opposite lasers are formed by the 61 st laser emitter 1-6 at the lower part of the vacuum cavity 1-2, and the intersection of the lasers is positioned at the central position of the lower part of the vacuum cavity 1-2; the atom source 1-9 is connected with the lower part of the vacuum cavity 1-2.
The working mechanism is as follows:
the working process of the probe 1 roughly comprises five stages of atom cooling and trapping, atom group polishing, atom initial state preparation, atom interference and atom final state detection. During the cooling and confinement of atoms, the laser light emitted by the 61 st laser emitters 1-6 and the magnetic field generated by the anti-Helmholtz coils 1-5 form a three-dimensional magneto-optical trap at the center of the lower portion of the vacuum chamber 2. In a three-dimensional magneto-optical trap, atoms are subjected to a force directed towards the center of the magneto-optical trap, and atoms released by atom sources 1-9 are slowed and trapped. In a three-dimensional magneto-optical trap, cold radicals will be obtained. In the stage of throwing the clusters, the magnetic field generated by the anti-Helmholtz coil 1-5 is closed, the frequency of laser emitted by the 61 st laser emitter 1-6 is controlled, so that the cold clusters prepared in the magnetic light trap obtain an initial velocity in the vertical upward direction, and the cold clusters move in the vertical upward direction. In the vertical upward movement process, the detuning amount of the laser frequency emitted by the 61 st laser emitters 1-6 is increased, the laser power is reduced, the polarization gradient cooling is carried out, and the temperature of cold radicals is further reduced. And the laser emitted by the 2 nd laser emitter 1-7 is used for realizing the Raman speed selection and obtaining the cold atomic group with narrower speed distribution. In the initial state preparation stage of atoms, cold atoms are prepared to be a magnetic insensitive state (| m) of a ground state energy levelF＝0>State), the effect of the first order zeeman effect on the process of atomic interference is avoided. Assuming atomic ground state exists |1>And |2>Two energy levels, microwave emitters 1-4 emit microwaves that can transit atoms between two magnon levels of the ground state energy levels, with which the atoms can be made to |1, mF＝0>(or |2, m)F＝0>) Attitude, | mF＝0>States are first order insensitive to magnetic fields.
In the atomic interference stage, the 2 nd laser emitter 1-7 emits laser upwards, the laser is reflected by the reflector 1-1 to generate downward laser, and two beams of laser which are transmitted upwards and downwards form Raman laser. And controlling the opening and closing of the 2 nd laser emitter 1-7 to generate three Raman light pulses, wherein the three Raman light pulses respectively enable the atomic groups to split, reflect and combine, and the atomic groups evolve along two paths. After the third beam of Raman light pulse acts, atoms interfere. After the interference, the atom will be in the superposition state of |1> and |2> with a certain probability distribution. In the atomic final state detection stage, the fluorescence signal of the interfered atom is detected by using the photodetectors 1-8, and the probability that the atom is in the ground state |1> or |2> is measured. The frequency of the chirped raman light will observe interference fringes of atoms. Since the atomic interference process is influenced by gravity, the interference fringe phase will contain gravity information. By measuring the phase of the interference fringes, the magnitude of the gravitational acceleration can be measured. The magnetic shields 1-10 are used to suppress the influence of the ambient magnetic field on the atomic interference process and the gravity measurement results.
Reflecting mirror 1-1
The reflecting mirror 1-1 is a plane reflecting mirror, and is a commercially available part.
② vacuum cavity 1-2
The vacuum cavity 1-2 is a cavity with vacuum inside, the upper part and the middle part are cylinders, and the lower part is a 10-18 surface body; the top of the device is provided with 1 light-transmitting window, the middle part is provided with 2-4 light-transmitting windows, and the lower part is provided with 10-18 light-transmitting windows.
③ bias magnetic field coil 1-3
The bias magnetic field coils 1-3 are coils wound by copper wires or other conducting wires.
Fourthly, microwave emitter 1 to 4
The microwave launcher 1-4 is a microwave launcher composed of microwave source, microwave power amplifier and microwave adapter, and the microwave adapter is at the end.
Reverse Helmholtz coil 1-5
The anti-Helmholtz coils 1-5 are coils formed by winding copper wires or other conducting wires and comprise 2 groups of coils, and the current directions in the 2 groups of coils are opposite.
Sixthly, 1 to 6 th laser transmitter and 1 to 7 th laser transmitter of 1 to 6
The 1 st laser emitter 1-6 and the 2 nd laser emitter 1-7 are laser emitting devices composed of general optical devices such as lasers, lenses, optical fibers, acousto-optic modulators and electro-optic modulators, and the tail ends of the laser emitting devices can be optical fiber collimating lenses or reflectors.
Seventhly, photoelectric detectors 1-8
The photodetectors 1 to 8 are devices for converting optical signals into electrical signals, and are external members, such as silicon photodetectors available from hamamatsu corporation.
Source of atoms 1-9
The atom source 1-9 is an alkali metal element releasing device, which is a commercially available device and can release one or more atom vapors of alkali metal elements such as lithium, sodium, potassium, rubidium, cesium and the like, for example, an alkali metal releasing agent from Seas company is selected.
Ninthly magnetic shielding cover 1-10
The magnetic shield 1-10 is a cylindrical shield made of permalloy material, which can largely shield the environmental magnetic field.
2) Inclinometer 2
The inclinometer 2 is a biaxial inclinometer, which is a commercially available part, such as an inclinometer of model ACA826T-03-232 of Raffing company; the inclinometer 2 can measure the inclination angles of the probe 1 in the directions of an x axis and a y axis of a horizontal plane, wherein the x axis and the y axis are two mutually vertical axes of the horizontal plane; the inclination data output by the inclinometer 2 can be recorded or collected by the computer 8.
3) Electric supporting foot 3
As shown in fig. 3, the electric supporting foot 3 comprises a fixed sleeve 3-1, a limiting hole 3-1-1, a bearing 3-2, an electric telescopic rod 3-3, a first supporting block 3-4, a motor 3-5, a motor rotating shaft 3-5-1 and a coupling device 3-6;
the connection relation is as follows:
the upper part in the fixed sleeve 3-1 is provided with a motor 3-5, the middle part is provided with a coupling device 3-6 and a bearing 3-2, and the lower part is provided with an electric telescopic rod 3-3; the motor rotating shaft 3-5-1 is connected with the upper part of the coupling device 3-6, the outer side of the coupling device 3-6 is connected with the inner side of the bearing 3-2, the outer side of the bearing 3-2 is connected with the fixed sleeve 3-1, the lower part of the coupling device 3-6 is connected with the electric telescopic rod 3-3, the electric telescopic rod 3-3 penetrates through the limiting hole 3-1-1 in the fixed sleeve 3-1, and the bottom of the electric telescopic rod 3-3 is connected with the 1 st supporting block 3-4.
Firstly, fixing sleeve 3-1
The fixed sleeve 3-1 is a cylinder with a bottom, the bottom of the fixed sleeve is provided with a limiting hole 3-1-1 with 3-12 edges, and a groove is arranged in the fixed sleeve 3-1 and used for fixing the bearing 3-2; the fixing sleeve 3-1 is also provided with a screw hole and a through hole for fixing the motor 3-5 to the fixing sleeve 3-1 and fixing the fixing sleeve 3-1 to the supporting plate 5.
② bearings 3-2
The bearing 3-2 is a commercially available part for reducing friction.
③ electric telescopic rod 3-3
The electric telescopic rod 3-3 is a threaded rod, and a cylinder body matched with the limiting hole 3-1-1 is arranged at the lower part of the threaded rod to prevent the electric telescopic rod 3-3 from rotating.
Fourthly, the 1 st supporting block 3 to 4
The 1 st supporting block 3-4 can be a cone, and the bottom material of the cone is silicon nitride ceramics or other high-hardness wear-resistant materials.
Motor 3-5
The motor 3-5 is a stepping motor, adopts a harmonic speed reduction mode, is a purchased part and comprises a motor rotating shaft 3-5-1, and the rotating direction and the number of turns of the motor rotating shaft can be controlled by a circuit 7. The connection mode of the motor rotating shaft 3-5-1 and the coupling device 3-6 adopts a fastening or looping connection mode.
Sixth, coupling device 3-6
The coupling device 3-6 can be a cylinder, the upper part of the coupling device is provided with a long hole matched with the motor rotating shaft 3-5-1, the bottom of the coupling device is provided with a long hole matched with the electric telescopic rod 3-3, the side surface of the coupling device is provided with a screw hole for fixing the motor rotating shaft 3-5-1 and the electric telescopic rod 3-3, and the interior of the coupling device is hollow. The coupling device 3-6 can rotate along with the motor 3-5, and when the coupling device 3-6 rotates along with the motor 3-5, the electric telescopic rod 3-3 stretches up and down in the coupling device 3-6.
4) Common supporting foot 4
Referring to fig. 4, the common supporting foot 4 comprises a telescopic rod 4-1, a threaded sleeve 4-2 and a 2 nd supporting block 4-3 which are connected in sequence from top to bottom.
Extension rod 4-1
The telescopic rod 4-1 is a threaded rod and is a purchased part.
② thread sleeve 4-2
The threaded sleeve 4-2 is a cylinder, the interior of the threaded sleeve is hollow, threads matched with the telescopic rod 4-1 are arranged on the threaded sleeve, and a bulge is arranged on the outer side of the threaded sleeve and connected with the supporting plate 5.
Third 2 support Block 4-3
The No. 2 supporting block 4-3 can be a cone, and the bottom material of the cone is silicon nitride ceramics or other high-hardness wear-resistant materials.
The effect of the common supporting leg 4 is:
when the telescopic rod 4-1 is manually rotated, the telescopic rod 4-1 can be vertically stretched relative to the threaded sleeve 4-2 and the supporting plate 5, namely, when the telescopic rod 4-1 is manually rotated, the common supporting rod 4 can be vertically stretched.
5) Supporting plate 5
The supporting plate 5 can be a circular plate with 3 symmetrical protrusions, and the protrusions are provided with through holes matched with the electric supporting legs 3 or the common supporting legs 4. When the electric supporting legs 3 or the common supporting legs 4 extend and contract, the inclination angles of the supporting plate 5 and the probe 1 fixed on the supporting plate 5 in the horizontal plane change.
5) Support surface 6
The support surface 6 is the ground or other support plane at the point of gravity measurement.
6) Circuit 7
The circuit 7 is a circuit matched with the motors 3-5 and is a purchased part, such as a circuit selected from a model of CRD5103PB of Oriental Motor company. The output signal of the circuit 7 is controlled by a computer 8, and the output signal can control the rotating direction and the rotating number of turns of the motors 3-5.
7) Computer 8
The computer 8 is a purchased part and is embedded with control software, such as LabVIEW software.
The control flow is as follows:
firstly, control software in the computer 8 generates control signals, and the control signals comprise information such as the rotation direction and the rotation number of turns of the motor.
And the control signal is transmitted to the circuit 7, and the circuit 7 converts the control signal into a signal which can be identified by the motor 3-5.
And the circuit 7 outputs signals to the motors 3-5, the motors 3-5 correspondingly rotate, and the electric supporting legs 3 stretch up and down.
Second, attitude adjusting method (method for short)
Referring to fig. 5, the main function of the method is to perform attitude adjustment on the cold atom interference type gravity meter probe 1, so that the direction of the operating laser wave vector of the cold atom interference type gravity meter is parallel to the gravity direction, thereby reducing the error of the gravity measurement system to the maximum extent.
The method includes a calibration process and an adjustment process.
The calibration process includes:
A. changing the probe attitude-301 point by point
By using a computer 8, the posture of the probe 1 is changed point by point within a certain angle range by controlling the extension and retraction of the electric supporting legs 3;
B. record Tilt data-302, while recording Probe output-303
At each attitude point, recording the dip angle value output by the inclinometer 2; simultaneously, recording the gravity acceleration or the atomic interference fringe phase output by the probe 1;
C. fitting-304
Fitting the recorded dip angle value and the gravity acceleration (or the atomic interference fringe phase), determining the dip angle value output by the inclinometer 2 when the operation laser wave vector direction is parallel to the gravity direction, and taking the dip angle value as the calibration dip angle value of the probe 1;
the adjusting process comprises the following steps:
a. probe 1 Placement-305
Placing the device at a gravity measurement point;
b. reading Tilt-306
Reading the dip angle value output by the inclinometer 2;
PID Algorithm-307
Comparing the inclination angle value output by the inclinometer 2 with the calibration inclination angle value, and calculating by using a PID algorithm to obtain a feedback signal;
d. electric support leg expansion-308
The feedback signal is output to a circuit 7 to control the expansion of the electric supporting leg 3;
e. the value of the inclination angle is equal to the value of the calibrated inclination angle-309
The posture of the probe 1 is adjusted by controlling the extension and contraction of the electric supporting legs 3 until the dip angle value output by the inclinometer 2 is equal to the calibration dip angle value.
The posture of the probe 1 is changed point by point in a mode that the posture of the probe 1 rotates around an x axis and a y axis independently or rotates around the x axis and the y axis in a linkage mode, and the x axis and the y axis are two mutually vertical axes of a horizontal plane.
When the mode of independently rotating around the x axis and the y axis is adopted, firstly, the posture of the probe 1 rotates around the x axis, the inclination angle of the probe 1 in the y axis direction is changed, meanwhile, the inclination angle in the x axis direction is kept unchanged, and the calibration inclination angle value in the y axis direction is determined in a fitting mode. And then adjusting the inclination angle of the probe 1 in the y-axis direction to be a calibration inclination angle value in the y-axis direction, rotating the posture of the probe 1 around the y-axis, and determining the calibration inclination angle value in the x-axis direction. The order of rotation of the probe 1 about the x-axis and y-axis may be switched.
When the mode of linkage rotation around the x axis and the y axis is adopted, the posture of the probe 1 rotates around the x axis and the y axis simultaneously.
The method can quickly and automatically determine the calibration inclination angle value, and automatically adjust the posture of the probe 1 to the calibration inclination angle value, so that the operation laser wave vector direction is parallel to the gravity direction.
Third, the working mechanism
The cold atom interference type gravity meter probe 1 has the main function of carrying out posture adjustment on the cold atom interference type gravity meter probe 1, so that the operation laser wave vector direction is parallel to the gravity direction, and the error of a gravity measurement system is reduced to the greatest extent.
The cold atom interference type gravimeter is a high-precision absolute gravimeter based on atom interference technology, and in a uniform gravity field, the phase of atom interference fringes output by a probe 1 is
Wherein k iseffIs the effective wave vector of the Raman laser (operating laser), T is the time interval of the Raman light pulse, and g is the gravity acceleration. As shown in the formula (1), the phase of the atomic interference fringe is measured
The magnitude of the gravitational acceleration can be measured. However, when the probe is used1 is placed at a gravity measurement point for measurement, and the Raman laser effective wave vector k is caused by the posture inclination of the probe 1 and the likeeffThe direction is not parallel to the gravity direction, and the actually measured phase of the interference fringe is
In the formula, theta is an included angle between two straight lines along the effective wave vector direction of the Raman laser and the gravity direction. When the posture of the probe of the gravimeter is inclined slightly, Taylor expansion can be carried out on the cos function, and the formula (2) can be written as
As can be seen from the equations (2) and (3), the included angle θ changes the phase
Resulting in systematic errors in the gravity measurements.
The Raman laser comprises laser emitted by the 2 nd laser emitter 1-7 and laser reflected by the reflector 1-1, and the wave vectors of the two laser beams are respectively k1And k2Then the effective wave vector of the Raman laser is keff＝k1-k2. In general, when a cold atom interference type gravity meter is built, the wave vector k is adjusted1And k2In such a way that they are approximately parallel, e.g. along wave vector k1And k2The angle η between two straight lines of direction can be controlled below1 μ rad in gravity measurement of μ Gal, the systematic error caused by the angle η is small and negligibleeff、k1And k2Compared with the included angle η, if the posture of the probe 1 is not adjusted, the included angle theta is larger and can reach the mrad magnitude, and the included angle theta can cause a large system error.
The invention can adjust the posture of the probe 1, so that the wave vector direction of the Raman laser (operation laser) is parallel to the gravity direction, namely the included angle theta approaches to 0. The attitude of the probe 1 can be characterized by the value of the inclination angle output by the inclinometer 2. Firstly, when determining which value the inclination angle takes, the direction of the wave vector of the operation laser is parallel to the gravity direction. And taking the inclination angle value when the operating laser wave vector direction is parallel to the gravity direction as a calibration inclination angle value, wherein the calibration inclination angle value comprises an x-axis direction calibration inclination angle value and a y-axis direction calibration inclination angle value. The process of determining the value of the calibration inclination is called the calibration process. In the calibration process, the computer 8 controls the stretching of the electric supporting legs 3, the posture of the probe 1 is changed in a certain angle range, the included angle theta is scanned, the inclination angle of each posture point is recorded, and the gravity acceleration or the interference fringe phase outputted by the probe 1 is recorded. From equation (3), a calibration tilt value can be determined by fitting the recorded data.
And after the calibration inclination angle value is determined, comparing the real-time inclination angle value and the calibration inclination angle value of the probe 1, adjusting the posture of the probe 1, and adjusting the inclination angle of the probe 1 to the calibration inclination angle value, wherein the operation laser wave vector direction is parallel to the gravity direction.
1. Example 1
The probe 1 is85An Rb cold atom interference type gravimeter probe, wherein the weight of a probe 1 is about 50 kg; the inclinometer 2 is a Rifen ACA826T-03-232 model biaxial inclinometer, and the inclination angle measurement range is +/-3 degrees; the limiting hole 3-1-1 on the fixed sleeve 3-1 in the electric supporting foot 3 is a 6-sided polygon, the bearing 3-2 is a thrust ball bearing of model 51101 of Skaifu corporation, the diameter of the electric telescopic rod 3-3 is 8mm, an area of 50mm in the vertical direction of the electric telescopic rod is distributed with a superfine thread with a thread pitch of 0.5mm, the 1 st supporting block 3-4 is a cone, the bottom of the cone is made of chrome steel, the motor 3-5 is a motor of model PK513PB-H100S of the eastern motor company, the maximum static torque of excitation can reach 0.6 N.m, the long holes at the upper end and the lower end of the coupling device 3-6 are respectively matched with the sizes of the motor rotating shaft 3-5-1 and the electric telescopic rod 3-3, and the connection mode between the motor rotating shaft 3-5-1 and the; the diameter of a telescopic rod 4-1 in the common supporting leg 4 is 8mm, superfine threads with the thread pitch of 0.5mm are distributed on a region 50mm in the vertical direction of the telescopic rod 4-1, the threads in a thread sleeve 4-2 are matched with the threads of the telescopic rod 4-1, a second supporting block 4-3 is a cone, and the bottom of the cone is made of chromium steel; the supporting plate 5 is a circular plate with the diameter of 450mm, and 3 bulges are symmetrically distributed on the outer side of the circular plateWherein 2 bulges are fixed with electric supporting feet 3, and 1 bulge is fixed with a common supporting foot 4; the supporting surface 6 is the ground at the gravity measuring point, the circuit 7 is a circuit matched with the motor 3-5, and a circuit of the model of CRD5103PB of eastern motor company is selected; the computer 8 is a 610L model computer of the Hua technology, and LabVIEW software is installed in the computer 8.
In this embodiment, the tilt angle value output by the inclinometer 2 can be collected by the computer 8 in real time, and the computer 8 outputs a control signal to the circuit 7. The circuit 7 outputs signals to the electric supporting legs 3, controls the extension and retraction of the 2 electric supporting legs, and adjusts the inclination angles of the probe 1 in the directions of the x axis and the y axis of the horizontal plane. First, the electric support legs 3 are controlled to rotate the probe 1 around the x-axis, and the tilt angle of the probe 1 in the y-axis direction is changed point by point within a certain angle range (for example, -2mrad to 2mrad) while keeping the tilt angle of the probe 1 in the x-axis direction constant. The tilt angle value at each attitude point is recorded, and the gravity acceleration (or interference fringe phase) output by the probe 1, and the recorded data points will be as shown in fig. 6. In fig. 6, the abscissa is the tilt angle value in the y-axis direction output by the inclinometer, the ordinate is the gravitational acceleration (or the phase of the interference fringes) output by the probe 1, and the black point is the data point at each attitude point. As can be seen from the formula (3), a unitary quadratic function can be used to fit the data points, and the black curve in fig. 6 is the quadratic curve obtained by fitting. When the angle theta is equal to 0, the phase of the interference fringe
And taking an extreme value. Therefore, the inclination angle value corresponding to the extreme value of the unitary quadratic function is the calibration inclination angle value in the y-axis direction. The calibration tilt value in the x-axis direction can also be determined in the same way.
After the calibration inclination angle value is determined, the real-time inclination angle value and the calibration inclination angle value of the probe 1 are compared, a PID algorithm is utilized to calculate a feedback signal, the stretching of the electric supporting leg 3 is controlled, and the posture of the probe 1 is adjusted until the inclination angle value output by the inclinometer 2 is equal to the calibration inclination angle value.
2. Example 2
The probe 1 is87The weight of the probe 1 of the Rb cold atom interference type gravimeter is about 40 kg; the inclinometer 2 is a Raffing company ACA620T-05-v1 model biaxial inclinationThe inclination angle measuring range of the angle instrument is +/-5 degrees, a limiting hole 3-1-1 on a fixing sleeve 3-1 in an electric supporting leg 3 is 8-sided, a bearing 3-2 is a thrust ball bearing of 51100 model of Skaifu corporation, the diameter of an electric telescopic rod 3-3 is 6mm, an ultrafine thread with the thread pitch of 0.25mm is distributed on a region 35mm in the vertical direction of the electric telescopic rod 3-3, a first supporting block 3-4 is in a spherical shape and made of silicon nitride ceramics, a motor 3-5 is a PK 513-PB-H50S model motor of Oriental Motor corporation, the maximum excitation static torque of the motor can reach 0.4 N.m, long holes at the upper end and the lower end of a coupling device 3-6 are respectively matched with the sizes of a motor rotating shaft 3-5-1 and the electric telescopic rod 3-3, the connection mode between the motor rotating shaft 3-5-1 and the coupling device 3-6 is a loose joint connection mode, a supporting plate 5 is a rectangular flat plate of × mm, 3-5 is fixed with 3, a supporting plate 5 is an isolation platform, a circuit of a DEL368 computer is 5000 CRLD circuit, and a notebook computer is installed in a DEL 368 computer.
In this embodiment, 3 electric support legs 3 are included, and the posture of the probe 1 in the x-axis and y-axis directions is changed in a linked manner within a certain angle range by controlling the extension and retraction of the electric support legs 3, and the tilt angle value output by the inclinometer 2 and the gravitational acceleration (or the interference fringe phase) output by the probe 1 are recorded. And fitting the recorded data points by using a binary function, and determining the calibration inclination angle values of the horizontal plane in the directions of the x axis and the y axis through the function obtained by fitting. After the calibration inclination angle value is determined, the stretching of the electric supporting legs 3 is controlled, and the posture of the probe 1 is adjusted to a calibration state.
Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.
Fourth, application
The cold atom interference type gravimeter has wide application prospect in the fields of geophysics, geodesic survey, metrology, inertial navigation, resource exploration and the like.
Claims (5)
1. The utility model provides an attitude adjusting device for cold atom interference type gravimeter probe which characterized in that:
comprises a probe (1), an inclinometer (2), an electric supporting leg (3), a common supporting leg (4), a supporting plate (5), a supporting surface (6), a circuit (7) and a computer (8);
the connection relation is as follows:
1 support plate (5), 3 electric support legs (3) or 2 electric support legs (3) and 1 common support leg (4) are arranged on the support surface (6); a probe (1) is arranged on the supporting plate (5), and the inclinometer (2) is arranged on the probe (1) or the supporting plate (5); the electric supporting leg (3), the circuit (7) and the computer (8) are connected in sequence; the inclinometer (2) is connected with the computer (8).
2. The attitude adjustment device according to claim 1, wherein:
the electric supporting leg (3) comprises a fixed sleeve (3-1), a limiting hole (3-1-1), a bearing (3-2), an electric telescopic rod (3-3), a 1 st supporting block (3-4), a motor (3-5), a motor rotating shaft (3-5-1) and a coupling device (3-6);
the connection relation is as follows:
a motor (3-5) is arranged at the upper part in the fixed sleeve (3-1), a coupling device (3-6) and a bearing (3-2) are arranged at the middle part, and an electric telescopic rod (3-3) is arranged at the lower part; the motor rotating shaft (3-5-1) is connected with the upper part of the coupling device (3-6), the outer side of the coupling device (3-6) is connected with the inner side of the bearing (3-2), the outer side of the bearing (3-2) is connected with the fixed sleeve (3-1), the lower part of the coupling device (3-6) is connected with the electric telescopic rod (3-3), the electric telescopic rod (3-3) penetrates through the limiting hole (3-1-1) in the fixed sleeve (3-1), and the bottom of the electric telescopic rod (3-3) is connected with the 1 st supporting block (3-4);
the limiting hole (3-1-1) is designed to be hexagonal;
the lower part of the electric telescopic rod (3-3) is provided with a column body matched with the limiting hole (3-1-1) to prevent the electric telescopic rod (3-3) from rotating;
the motor (3-5) is a stepping motor, the motor adopts a harmonic speed reduction mode, and the connection between the motor rotating shaft (3-5-1) and the coupling device (3-6) adopts a fastening or looping connection mode.
3. The attitude adjustment device according to claim 1, wherein:
the common supporting leg (4) comprises a telescopic rod (4-1), a threaded sleeve (4-2) and a No. 2 supporting block (4-3) which are sequentially connected from top to bottom; the extension of the common supporting leg (4) can be adjusted only manually.
4. A posture adjustment method of a posture adjustment apparatus as claimed in claim 1, 2 or 3, characterized by comprising a calibration process and an adjustment process:
the calibration process includes:
A. changing the posture of the probe point by point;
B. recording inclination angle data and simultaneously recording probe output;
C. fitting;
the adjusting process comprises the following steps:
a. placing a probe;
b. reading the inclination angle;
a PID algorithm;
d. the electric supporting leg stretches out and draws back;
e. the tilt value is equal to the calibrated tilt value.
5. The attitude adjustment method according to claim 4, characterized in that:
the mode of changing the posture of the probe (1) point by point is as follows: the posture of the probe (1) rotates around an x axis and a y axis independently or rotates around the x axis and the y axis in a linkage manner, and the x axis and the y axis are two mutually vertical axes of a horizontal plane;
when the mode of independently rotating around the x axis and the y axis is adopted, firstly, the posture of the probe (1) rotates around the x axis, the inclination angle of the probe (1) in the y axis direction is changed, meanwhile, the inclination angle in the x axis direction is kept unchanged, and the calibration inclination angle value in the y axis direction is determined in a fitting mode; then adjusting the inclination angle of the probe (1) in the y-axis direction to be a calibration inclination angle value in the y-axis direction, rotating the posture of the probe (1) around the y-axis, and determining the calibration inclination angle value in the x-axis direction; the order of rotation of the probe (1) about the x-axis and the y-axis can be interchanged;
when the mode of linkage rotation around the x axis and the y axis is adopted, the posture of the probe (1) rotates around the x axis and the y axis simultaneously.
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Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112683257A (en) * | 2020-12-07 | 2021-04-20 | 华中光电技术研究所（中国船舶重工集团公司第七一七研究所） | Active tilt control system and method for four-pulse cold atom interference gyroscope |
| CN112698417A (en) * | 2020-12-16 | 2021-04-23 | 华中光电技术研究所（中国船舶重工集团公司第七一七研究所） | Cold atom absolute gravimeter capable of being used for dynamic measurement |
| CN112729355A (en) * | 2020-12-24 | 2021-04-30 | 华中光电技术研究所（中国船舶重工集团公司第七一七研究所） | Method for calibrating Raman light incidence angle suitable for atomic interferometer |
| CN113466958A (en) * | 2021-06-23 | 2021-10-01 | 天水师范学院 | Single-beam atomic gravity gradient sensor based on complementary reflector |
| CN115469369A (en) * | 2022-07-08 | 2022-12-13 | 哈尔滨工业大学 | Cold atom Raman reflector installation error angle correction method |
| CN116538402A (en) * | 2023-07-07 | 2023-08-04 | 广东威纳格科技有限公司 | Foundation device and method for adjusting attitude of atomic interferometer |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112683257A (en) * | 2020-12-07 | 2021-04-20 | 华中光电技术研究所（中国船舶重工集团公司第七一七研究所） | Active tilt control system and method for four-pulse cold atom interference gyroscope |
| CN112698417A (en) * | 2020-12-16 | 2021-04-23 | 华中光电技术研究所（中国船舶重工集团公司第七一七研究所） | Cold atom absolute gravimeter capable of being used for dynamic measurement |
| CN112729355A (en) * | 2020-12-24 | 2021-04-30 | 华中光电技术研究所（中国船舶重工集团公司第七一七研究所） | Method for calibrating Raman light incidence angle suitable for atomic interferometer |
| CN113466958A (en) * | 2021-06-23 | 2021-10-01 | 天水师范学院 | Single-beam atomic gravity gradient sensor based on complementary reflector |
| CN115469369A (en) * | 2022-07-08 | 2022-12-13 | 哈尔滨工业大学 | Cold atom Raman reflector installation error angle correction method |
| CN116538402A (en) * | 2023-07-07 | 2023-08-04 | 广东威纳格科技有限公司 | Foundation device and method for adjusting attitude of atomic interferometer |
| CN116538402B (en) * | 2023-07-07 | 2023-09-19 | 广东威纳格科技有限公司 | Foundation device and method for adjusting attitude of atomic interferometer |
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Inventor after: Li Jinting Inventor after: Wang Jin Inventor after: Zhan Mingsheng Inventor after: Fang Jie Inventor after: Ge Guiguo Inventor after: He Meng Inventor after: Zhang Danfang Inventor after: Chen Xi Inventor after: Zhong Jiaqi Inventor after: Tang Biao Inventor after: Li Runbing Inventor before: Li Jinting Inventor before: Wang Jin Inventor before: Zhan Mingsheng Inventor before: Fang Jie Inventor before: Ge Guiguo Inventor before: He Meng Inventor before: Zhang Danfang Inventor before: Chen Xi Inventor before: Zhong Jiaqi Inventor before: Tang Biao Inventor before: Li Runbing |