Pillar platform integrated Coriolis north seeker and north seeking method thereof

Abstract

The invention relates to the technical field of inertial navigation, and provides a pillow block integrated Coriolis north seeker and a north seeking method thereof. The plummer block integrated rotating table comprises a circular rotating table and a rotating shaft extending from the end face of the circular rotating table, and the rotating shaft is connected with the output end of the rotating motor; the acceleration sensor is fixed on the circular rotary table; the angle sensor is fixed on the rotating shaft; and the upper computer performs rotation period division by using the output signal of the angle sensor, and performs calculation according to the output signal of the acceleration sensor in a rotation period to obtain a north azimuth angle. The plummer block integrated rotating table is adopted, the mass of the rotating table is balanced, vibration interference during high-speed rotation is effectively restrained, and the precision of calculating the north azimuth angle is improved; the azimuth angle calculation is carried out on the rotation full-period data of the acceleration sensor, so that the random error caused by few data sample points can be reduced, and the north-seeking precision is greatly improved.

Description

Technical Field

[0001] The invention relates to the technical field of inertial navigation, and in particular to a pillow block integrated Coriolis north finder and a north finding method thereof. Background Art

[0002] North-seeking technology refers to the technology of determining the true north direction of the earth through various devices and methods. Inertial north-seeking technology is one of them, which uses inertial components such as gyroscopes and accelerometers to measure the north component of the earth's rotational angular velocity to determine the true north direction. Inertial devices are not affected by external environmental conditions such as magnetic field interference, weather changes, terrain obstructions and other factors. They have the advantages of long-term stable operation, high accuracy, full autonomy, and short measurement time. They are often used in the initial alignment of missiles, artillery aiming and launching, geophysical exploration, geodesy, coal mining and oil drilling.

[0003] The structure of the gyroscope system is complex, and different types of gyroscopes generally have contradictions between small size, high precision, high efficiency, strong anti-interference and low cost. Therefore, the research of high-precision, small size, high efficiency and low-cost north finder is still an important research topic in the field of inertial navigation.

[0004] In the 1980s, with the advancement of accelerometer manufacturing technology, a non-gyroscopic inertial measurement unit (NIMU) appeared abroad. It abandoned the expensive gyro and used three orthogonally placed and independently rotating accelerometers for north-seeking attitude settlement, which greatly reduced the manufacturing cost. It also adopted a dynamic working mode with fast response speed, avoiding the influence of gyro drift and other factors on orientation accuracy.

[0005] In the 1990s, some domestic scholars proposed a new idea of ​​using accelerometers to replace gyroscopes for north-seeking. Accelerometer north-seeking adopts a dynamic north-seeking method with potential advantages of fast response speed, high accuracy and low cost. In recent years, research on accelerometer north-seeking has gradually increased.

[0006] The existing accelerometer north-finding solution is to place the accelerometer symmetrically on a connecting rod symmetrical structure turntable, with the sensitive axis of the accelerometer pointing vertically upward. The connecting rod structure turntable moves at a uniform speed driven by a motor, and the accelerometer measures the absolute acceleration at four reference points to calculate the azimuth angle.

[0007] The existing north-seeking scheme belongs to a turntable with a symmetrical connecting rod structure. The connecting rod connection is a split structure, which is only suitable for low-speed rotation. It will produce large vibrations when rotating at high speed. In addition, this scheme does not perform mass balancing on the connecting rod, and places the accelerometer directly at both ends of the connecting rod. The unbalanced radial mass of the connecting rod will cause eccentricity, forcing the entire device to vibrate during rotation; the vibration acceleration generated by the vibration will significantly reduce the signal-to-noise ratio of the accelerometer output signal, which is not conducive to improving the accuracy of solving the north azimuth. Summary of the invention

[0008] In view of the deficiencies in the prior art, the present invention provides a pillow block integrated Coriolis north-finding instrument and a north-finding method thereof, aiming to solve at least some of the technical problems existing in the prior art.

[0009] To achieve the above object, the present invention provides the following technical solutions:

[0010] In one aspect, the present invention provides a pillow block integrated Coriolis north finder, comprising:

[0011] Rotating electrical machines;

[0012] A pillow block integrated rotating platform, comprising a circular rotating platform and a rotating shaft extending from the end surface of the circular rotating platform, wherein the rotating shaft is connected to the output end of the rotating motor, and the pillow block integrated rotating platform performs rotating motion under the drive of the rotating motor;

[0013] An acceleration sensor, which is fixed on the circular turntable and is used to sense acceleration and output a signal;

[0014] An angle sensor, fixed on the rotating shaft, used to measure the rotation angle of the pillow block integrated rotating table and output a signal;

[0015] The host computer is used to receive the output signal of the acceleration sensor and the output signal of the angle sensor, divide the rotation period by the output signal of the angle sensor, and calculate the north azimuth according to the output signal of the acceleration sensor within one rotation period.

[0016] Preferably, the circular turntable is provided with two symmetrically arranged fixing holes, the acceleration sensors have two and are respectively fixed in the two fixing holes, and the mass of the material removed when the fixing holes are opened is consistent with the mass of the acceleration sensors.

[0017] Preferably, the rotating shaft includes an upper half shaft extending from the upper end surface of the circular turntable and a lower half shaft extending from the lower end surface of the circular turntable.

[0018] The rotating motor is a hollow shaft motor, the output end of which is a hollow rotor, and the lower half shaft is inserted into and fixed in the hollow rotor.

[0019] Preferably, a high-speed rotating electrical connector is provided at the top end of the upper half shaft, and the high-speed rotating electrical connector is electrically connected to the acceleration sensor for transmitting the output signal of the acceleration sensor to the host computer.

[0020] Preferably, a wire-passing hole is provided inside the upper half shaft, and the connecting wire passes through the wire-passing hole to be electrically connected to the acceleration sensor and the high-speed rotating electrical connector.

[0021] Preferably, the upper half shaft is connected to the first fixed platform via a bearing, and the lower half shaft is connected to the second fixed platform via a bearing, and the first fixed platform and the second fixed platform are symmetrically arranged relative to the circular turntable.

[0022] Preferably, the angle sensor is fixed on the lower half shaft and is located between the second fixed platform and the rotating motor.

[0023] On the other hand, the present invention further provides a Coriolis north-finding method, using the pillow block integrated Coriolis north-finding instrument as described in any one of the above items, the method comprising:

[0024] The rotary motor drives the pillow block integrated rotary table to rotate at a preset speed;

[0025] Synchronously collect the output signal of the acceleration sensor and the output signal of the angle sensor;

[0026] The output signal of the angle sensor is used to divide the rotation period, and the north azimuth is calculated based on the output signal of the acceleration sensor within one rotation period.

[0027] Preferably, the step of calculating the north azimuth according to the output signal of the acceleration sensor within one rotation cycle specifically includes:

[0028] (1) According to the principle of acceleration synthesis, the north-seeking equation of the acceleration sensor is determined:

[0029] a=-g+a0+2Ωrω N cos(Ωt+θ)

[0030] a is the output signal of the acceleration sensor, g is the gravity acceleration, a0 is the zero bias of the acceleration sensor, Ω is the rotation angular velocity of the integrated rotary table, r is the distance from the sensitive axis of the acceleration sensor to the axis center of the integrated rotary table, ω N =ωcosφ is the north component of the earth's rotation angular velocity at this location, ω is the earth's rotation angular velocity, φ is the latitude of the location of the axis-type integrated rotating platform, and θ is the north azimuth; g and a0 are constants;

[0031] According to the trigonometric function and the difference angle formula, the above formula is transformed into the following form:

[0032] a=q1sinΩt+q2cosΩt+q3

[0033] Where: q1 = -2Ωrω N sinθ,q2=2Ωrω N cosθ,q3=-g+a0

[0034] The mathematical model of the acceleration sensor output signal is constructed as follows:

[0035] a i =q1sinΩt i +q2cosΩt i +q3 (i=1,2,3,…,n)

[0036] Among them, a i is the output signal of the acceleration sensor corresponding to the i-th sampling point, Ωt i is the angle of rotation of the integrated rotating table of the shaft table at the i-th sampling point;

[0037] (2) Take n groups of acceleration sensor output signals in the same rotation cycle to construct a set of equations:

[0038]

[0039] Construct a matrix from a system of equations:

[0040]

[0041] Solving the equation gives the values ​​of q1, q2, and q3.

[0042] (3) Establish the azimuth angle solution equation:

[0043]

[0044] The north azimuth θ can be calculated.

[0045] In summary, the present invention has the following beneficial effects compared with the prior art:

[0046] The present invention adopts a shaft-type integrated rotating table, and the acceleration sensor is fixed on the circular turntable of the shaft-type integrated rotating table. Compared with the traditional connecting rod turntable, the mass of the turntable is more balanced, and the circular turntable and the rotating shaft are arranged in an integrated manner, which effectively suppresses vibration interference during high-speed rotation, and is beneficial to improving the accuracy of solving the north azimuth angle; and the output signal of the angle sensor is used to divide the rotation cycle, and the north azimuth angle is solved according to the output signal of the acceleration sensor within a rotation cycle. By solving the azimuth angle of the full rotation cycle data of the acceleration sensor, the random error caused by the small number of data sample points can be reduced, and the north-seeking accuracy can be greatly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 A structural diagram of a pillow block integrated Coriolis north finder provided in this embodiment;

[0048] Figure 2 A schematic diagram of a pillow block integrated rotating table provided in this embodiment;

[0049] Figure 3 The Coriolis north-seeking principle diagram provided for this embodiment. DETAILED DESCRIPTION

[0050] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0051] Embodiment 1:

[0052] like Figure 1 and Figure 2 As shown, an embodiment of the present invention provides a pillow block integrated Coriolis north finder, comprising:

[0053] A rotating motor 6 having a speed output terminal;

[0054] The pillow block integrated rotating platform 2 comprises a circular rotating platform and a rotating shaft extending from the end surface of the circular rotating platform, wherein the rotating shaft is connected to the output end of the rotating motor 6, and the pillow block integrated rotating platform 2 performs rotating motion under the drive of the rotating motor 6;

[0055] An acceleration sensor 3, which is fixed on the circular turntable and is used to sense acceleration and output a signal;

[0056] An angle sensor 5, fixed on the rotating shaft, used to measure the rotation angle of the pillow block integrated rotating table and output a signal, and the rotation period of the pillow block integrated rotating table 2 can be divided according to the rotation angle measured by the angle sensor 5;

[0057] The host computer is used to receive the output signal of the acceleration sensor 3 and the output signal of the angle sensor 5, divide the rotation period by the output signal of the angle sensor 5, and calculate the north azimuth according to the output signal of the acceleration sensor 3 within one rotation period.

[0058] The present invention adopts a shaft-type integrated rotating table 2, and the acceleration sensor 3 is fixed on the circular turntable of the shaft-type integrated rotating table 2. Compared with the traditional connecting rod turntable, the turntable has a more balanced mass, and the circular turntable and the rotating shaft are arranged as an integrated body, which effectively suppresses vibration interference during high-speed rotation, and is beneficial to improve the accuracy of solving the north azimuth angle; and the output signal of the angle sensor 5 is used to divide the rotation period, and the north azimuth angle is solved according to the output signal of the acceleration sensor 3 within a rotation period. By solving the azimuth angle of the full rotation period data of the acceleration sensor 3, the random error caused by the small number of data sample points can be reduced, and the north-seeking accuracy can be greatly improved.

[0059] Preferably, the circular turntable is provided with two symmetrically arranged fixing holes 201, the acceleration sensor 3 has two and is respectively fixed in the two fixing holes 201, and the mass of the material removed when the fixing holes 201 are opened is consistent with the mass of the acceleration sensor 3, further ensuring the mass balance of the turntable and improving the accuracy of solving the north azimuth.

[0060] In a specific embodiment, the rotating shaft includes an upper half shaft extending from the upper end surface of the circular turntable and a lower half shaft extending from the lower end surface of the circular turntable, and both the upper half shaft and the lower half shaft are integrally arranged with the circular turntable. The rotating motor 6 is a hollow shaft motor, and its output end is a hollow rotor. The lower half shaft is inserted and fixed in the hollow rotor, so that the pillow block integrated rotating table 2 rotates under the drive of the hollow rotor. By inserting and fixing the lower half shaft of the pillow block integrated rotating table 2 in the hollow rotor of the rotating motor 6, the rotating shaft of the rotating motor 6 is omitted, and the connection between the two is more stable, and the overall structure is more compact.

[0061] Furthermore, a high-speed rotating electrical connector 1 is provided at the top of the upper half shaft, and the high-speed rotating electrical connector 1 is electrically connected to the acceleration sensor 3, and is used to transmit the output signal of the acceleration sensor 3 to the host computer. Specifically, the electrical connector 1 includes a rotor, and the rotor is coaxially connected to the top of the upper half shaft. A wire hole 202 is provided inside the upper half shaft, and the connecting wire passes through the wire hole 202 to be electrically connected to the acceleration sensor 3 and the high-speed rotating electrical connector 1, and the connecting wire will not be entangled during rotation. Preferably, it also includes a data acquisition module, and the data acquisition module is preferably a high-speed precision ADC module, which is used to synchronously collect the output signal of the acceleration sensor 3 and the output signal of the angle sensor 5, and transmit them to the host computer for processing.

[0062] In a preferred embodiment, the upper half shaft is connected to the first fixed platform through a bearing 4, and the lower half shaft is connected to the second fixed platform through a bearing 4. The first fixed platform and the second fixed platform are symmetrically arranged relative to the circular turntable, further ensuring the stability of the circular turntable during rotation.

[0063] Further preferably, the angle sensor 5 is fixed on the lower half shaft and is located between the second fixed platform and the rotating motor 6 to reduce the influence on the stability of the pillow block integrated rotating platform 2 during rotation.

[0064] Embodiment 2:

[0065] The embodiment of the present invention further provides a Coriolis north-finding method, using the pillow block integrated Coriolis north-finding instrument as described in the above embodiment 1, the method comprising:

[0066] The rotary motor drives the pillow block integrated rotary table to rotate at a preset speed, which is adjustable;

[0067] The host computer controls the data acquisition module to synchronously collect the output signal of the acceleration sensor and the output signal of the angle sensor;

[0068] The output signal of the angle sensor is used to divide the rotation period, and the north azimuth is calculated based on the output signal of the acceleration sensor within one rotation period.

[0069] Preferably, the step of calculating the north azimuth according to the output signal of the acceleration sensor within one rotation cycle specifically includes:

[0070] (1) According to the principle of acceleration synthesis, the north-seeking equation of the acceleration sensor is determined:

[0071] a=-g+a0+2Ωrω N cos(Ωt+θ)

[0072] a is the output signal of the acceleration sensor, g is the acceleration of gravity, a0 is the zero bias of the acceleration sensor, Ω is the rotation angular velocity of the integrated rotary table of the pillow block, the unit is degree / second or radian / second, r is the distance from the sensitive axis of the acceleration sensor to the axis center of the integrated rotary table of the pillow block, ω N =ωcosφ is the north component of the earth's rotation angular velocity at this location, ω is the earth's rotation angular velocity, φ is the latitude of the location of the axis-type integrated rotating platform, and θ is the north azimuth; g and a0 are constants;

[0073] According to the trigonometric function and the difference angle formula, the above formula is transformed into the following form:

[0074] a=q1sinΩt+q2cosΩt+q3

[0075] Where: q1 = -2Ωrω N sinθ,q2=2Ωrω N cosθ,q3=-g+a0

[0076] The mathematical model of the acceleration sensor output signal is constructed as follows:

[0077] a i =q1sinΩt i +q2cosΩt i +q3 (i=1,2,3,…,n)

[0078] Among them, t is time in seconds; i is the mathematical model sampling point, and one sampling point i corresponds to one time t i ; a iis the output signal of the acceleration sensor corresponding to the i-th sampling point; Ωt i It is the angle of rotation of the integrated rotating table of the shaft table at the i-th sampling point; the meanings of other letters are the same as above.

[0079] (2) Take n groups of acceleration sensor output signals in the same rotation cycle to construct a set of equations:

[0080]

[0081] Construct a matrix from a system of equations:

[0082]

[0083] Solving the equation gives the values ​​of q1, q2, and q3.

[0084] (3) Establish the azimuth angle solution equation:

[0085]

[0086] The north azimuth θ can be calculated.

[0087] The north-seeking method of the present invention simplifies the north-seeking equation and can reduce the random error caused by the small number of data sample points by solving the azimuth angle of the full-cycle rotation data of the acceleration sensor, thereby greatly improving the north-seeking accuracy.

[0088] Those skilled in the art will appreciate that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage and optical storage, etc.) containing computer-usable program code.

[0089] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0090] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0091] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0092] It is to be understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of the present invention, but the present invention is not limited thereto. For those of ordinary skill in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A pillow block integrated Coriolis north finder, characterized in that: include: Rotating electrical machines; A pillow block integrated rotating platform, comprising a circular rotating platform and a rotating shaft extending from the end surface of the circular rotating platform, wherein the rotating shaft is connected to the output end of the rotating motor, and the pillow block integrated rotating platform performs rotating motion under the drive of the rotating motor; An acceleration sensor, which is fixed on the circular turntable and is used to sense acceleration and output a signal; An angle sensor, fixed on the rotating shaft, used to measure the rotation angle of the pillow block integrated rotating table and output a signal; The host computer is used to receive the output signal of the acceleration sensor and the output signal of the angle sensor, divide the rotation period by the output signal of the angle sensor, and calculate the north azimuth according to the output signal of the acceleration sensor within one rotation period.

2. A pillow block integrated Coriolis north finder as claimed in claim 1, characterized in that: The circular turntable is provided with two symmetrically arranged fixing holes, the acceleration sensors have two and are respectively fixed in the two fixing holes, and the mass of the removed material when the fixing holes are opened is consistent with the mass of the acceleration sensors.

3. A pillow block integrated Coriolis north finder as claimed in claim 1, characterized in that: The rotating shaft includes an upper half shaft extending from the upper end surface of the circular turntable and a lower half shaft extending from the lower end surface of the circular turntable.

4. A pillow block integrated Coriolis north finder as claimed in claim 3, characterized in that: The rotating motor is a hollow shaft motor, the output end of which is a hollow rotor, and the lower half shaft is inserted into and fixed in the hollow rotor.

5. A pillow block integrated Coriolis north finder as claimed in claim 3, characterized in that: A high-speed rotating electrical connector is arranged at the top end of the upper half shaft, and the high-speed rotating electrical connector is electrically connected to the acceleration sensor and is used for transmitting the output signal of the acceleration sensor to the host computer.

6. A pillow block integrated Coriolis north finder as claimed in claim 5, characterized in that: A wire passing hole is provided inside the upper half shaft, and a connecting wire passes through the wire passing hole to be electrically connected to the acceleration sensor and the high-speed rotating electrical connector.

7. A pillow block integrated Coriolis north finder as claimed in claim 3, characterized in that: The upper half shaft is connected to the first fixed platform through a bearing, and the lower half shaft is connected to the second fixed platform through a bearing. The first fixed platform and the second fixed platform are symmetrically arranged relative to the circular turntable.

8. A pillow block integrated Coriolis north finder as claimed in claim 7, characterized in that: The angle sensor is fixed on the lower half shaft and is located between the second fixed platform and the rotating motor.

9. A Coriolis north-finding method, using the pillow block integrated Coriolis north-finding instrument as claimed in any one of claims 1 to 8, characterized in that: The method includes: The rotary motor drives the pillow block integrated rotary table to rotate at a preset speed; Synchronously collect the output signal of the acceleration sensor and the output signal of the angle sensor; The output signal of the angle sensor is used to divide the rotation period, and the north azimuth is calculated based on the output signal of the acceleration sensor within one rotation period.

10. A Coriolis north-finding method as claimed in claim 9, characterized in that: The method of calculating the north azimuth according to the output signal of the acceleration sensor within one rotation cycle specifically includes: (1) According to the principle of acceleration synthesis, the north-seeking equation of the acceleration sensor is determined: a=-g+a0+2Ωrω N cos(Ωt+θ) a is the output signal of the acceleration sensor, g is the gravity acceleration, a0 is the zero bias of the acceleration sensor, Ω is the rotation angular velocity of the integrated rotary table, r is the distance from the sensitive axis of the acceleration sensor to the axis center of the integrated rotary table, ω N =ωcosφ is the north component of the earth's rotation angular velocity at this location, ω is the earth's rotation angular velocity, φ is the latitude of the location of the axis-type integrated rotating platform, and θ is the north azimuth; g and a0 are constants; According to the trigonometric function and the difference angle formula, the above formula is transformed into the following form: a=q1sinΩt+q2cosΩt+q3 where: q1 = -2Ωrω N sinθ, q2 = 2Ωrω N cosθ, q3 = -g + a0 The mathematical model of the acceleration sensor output signal is constructed as follows: a i =q1sinΩt i +q2cosΩt i +q3 (i=1,2,3,…,n) Among them, a i is the output signal of the acceleration sensor corresponding to the i-th sampling point, Ωt i is the angle of rotation of the integrated rotating table of the shaft table at the i-th sampling point; (2) Take n groups of acceleration sensor output signals in the same rotation cycle to construct a set of equations: Construct a matrix from a system of equations: Solving the equation gives the values ​​of q1, q2, and q3. (3) Establish the azimuth angle solution equation: The north azimuth θ can be calculated.

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