阅读说明：本技术 一种小型飞行器的高精度质心惯量测量系统及测量方法 (High-precision mass center inertia measuring system and measuring method for small aircraft ) 是由 徐喆垚 张义超 解永锋 曹梦磊 孙戎 高骥 文艺 王利 陈益 周文勇 于 2019-09-29 设计创作，主要内容包括：一种小型飞行器的高精度质心惯量测量系统,属于飞行器质心惯量测量技术领域,包括被测物体安装盘1、速率陀螺2、球面轴承3、支持立柱4、配重悬挂装置(5、7、8、9)、配重质量块6、激励质量块10；球面轴承3分别与支持立柱4和被测物体安装盘1连接；配重悬挂装置(5、7、8、9)安装在被测物体安装盘1上靠近的支持立柱4的一侧；配重质量块6可拆卸的安装在配重悬挂装置(5、7、8、9)的不同位置；外部被测物体放置在被测物体安装盘1上；激励质量块10放置在被测物体安装盘1上；速率陀螺2用于测量被测物体安装盘1转动的角速度和姿态角。本发明系统可同时测量质心和惯量,测量周期短,系统简单。(A high-precision mass center inertia measurement system of a small aircraft belongs to the technical field of aircraft mass center inertia measurement, and comprises a measured object mounting disc 1, a rate gyro 2, a spherical bearing 3, a support upright post 4, a counterweight suspension device (5, 7, 8 and 9), a counterweight mass block 6 and an excitation mass block 10; the spherical bearing 3 is respectively connected with the supporting upright post 4 and the installation disc 1 of the object to be measured; the counterweight suspension devices (5, 7, 8 and 9) are arranged on one side of the measured object mounting plate 1 close to the supporting upright post 4; the counterweight mass block 6 is detachably arranged at different positions of the counterweight suspension devices (5, 7, 8, 9); an external object to be measured is placed on the object to be measured mounting plate 1; the excitation mass block 10 is placed on the installation plate 1 of the measured object; the rate gyro 2 is used for measuring the angular velocity and attitude angle of the rotation of the measured object mounting plate 1. The system can simultaneously measure the mass center and the inertia, and has short measurement period and simple system.)

1. A high-precision mass center inertia measurement system of a small aircraft is characterized by comprising a measured object mounting disc (1), a rate gyro (2), a spherical bearing (3), a support upright post (4), counterweight suspension devices (5, 7, 8 and 9), a counterweight mass block (6) and an excitation mass block (10);

the spherical bearing (3) is respectively connected with the supporting upright post (4) and the installation disc (1) of the object to be measured, so that the installation disc (1) of the object to be measured can swing around the spherical center of the spherical bearing (3); the counterweight suspension devices (5, 7, 8 and 9) are arranged on one side, close to the supporting upright post (4), of the installation plate (1) of the object to be measured; the counterweight mass block (6) is detachably arranged at different positions of the counterweight suspension devices (5, 7, 8, 9); an external object to be measured is placed on the object to be measured mounting plate (1); the excitation mass block (10) is arranged on the mounting disc (1) of the object to be measured;

the rate gyroscope (2) is used for measuring the rotating angular speed and attitude angle of the measured object mounting disc (1).

2. The system for measuring the high-precision centroid inertia of a small aircraft as claimed in claim 1, wherein the spherical bearing (3) is selected from an air-float spherical bearing or a micro-friction bearing.

3. The high-precision mass center inertia measurement system of the small aircraft according to claim 1, wherein the counterweight suspension devices (5, 7, 8, 9) are symmetrically arranged on the side, close to the support upright (4), of the measured object mounting plate (1) in a cross distribution manner.

4. A high precision centroid inertia measurement system for small aircraft according to claim 1, characterized in that said counterweight mass (6) comprises a plurality of masses of different weight specifications; the mounting position of each mass on the counterweight suspension device (5, 7, 8, 9) is adjustable.

5. A high precision centroid inertia measurement system for small aircraft according to claim 1, characterized in that said excitation mass (10) comprises a plurality of masses of different weight specifications.

6. A method for measuring the high-precision centroid inertia of a small aircraft, which is characterized in that the measuring system of claim 1 is adopted, and comprises the following steps:

s1, measuring the mass of the measured object, and then placing the measured object on the measured object mounting plate (1);

s2, enabling the installation disc (1) of the object to be measured to move freely, and increasing and decreasing counterweight mass blocks (6) on counterweight suspension devices (5, 7, 8 and 9) according to the rotation direction of the installation disc (1) of the object to be measured so that the free swinging angular speed of the installation disc (1) of the object to be measured does not exceed 2 degrees/S;

s3, selecting two or four opposite counterweight suspension devices (5, 7, 8, 9), and adding the same counterweight mass block (6) at the same position on the selected counterweight suspension devices (5, 7, 8, 9) to enable the gravity center of the added counterweight mass block (6) to be lower than the spherical center of the spherical bearing (3);

s4, placing the excitation mass block (10) on the measured object mounting disc (1), measuring the rotating angular speed and attitude angle of the measured object mounting disc (1) by using the rate gyroscope (2), and calculating the mass center and the moment of inertia of the measured object.

7. The method for measuring the mass center inertia of a small aircraft as claimed in claim 6, wherein the weight of the excitation mass (10) in S4 is not more than one tenth of the weight of the object to be measured.

8. The method for measuring the mass center inertia of a small aircraft as claimed in claim 6, wherein the mass center r of the object to be measured is_bComprises the following steps:

wherein m is the total mass of the installation disc (1) of the measured object, the rate gyro (2), the counterweight suspension devices (5, 7, 8, 9) and the counterweight mass block (6), r is the mass center of m, and m is the mass center of m_aFor measuring the mass of the object mounting plate (1), r_aIn order to measure the mass center of the object mounting plate (1), i is a first ordinal number, n is the number of the counterweight mass blocks (6),

the moment of inertia of the measured object is as follows:

wherein I is the total moment of inertia including the measured object mounting plate (1), the rate gyro (2), the counterweight suspension devices (5, 7, 8, 9), the counterweight mass block (6) and the excitation mass block (10), I^aIs a measured objectThe moment of inertia of the tray (1), i is a first ordinal number, n is the number of the counterweight mass blocks (6),

9. The method for measuring the high-precision centroid inertia of a small aircraft according to any one of claims 6 to 8, wherein the method for increasing or decreasing the counterweight mass (6) on the counterweight suspending device (5, 7, 8, 9) to make the free swing angular velocity of the object mounting plate (1) not more than 2 °/S in S2 comprises:

s21, after the installation disc (1) of the object to be measured is rotated to the horizontal position, according to the inclination direction of the installation disc (1) of the object to be measured, the free swinging angular speed of the installation disc (1) of the object to be measured does not exceed 2 degrees/S by increasing the counterweight mass block (6) and adjusting the position of the counterweight mass block (6);

s22, inclining the mounting plate (1) of the object to be measured by no more than 25 degrees; according to the movement direction of the mounting disc (1) of the object to be measured, the free swinging angular speed of the mounting disc (1) of the object to be measured is not more than 2 degrees/s by increasing the counterweight mass block (6) and adjusting the position of the counterweight mass block (6);

s23, repeating the steps S21-S22 until the free swinging angular speed in S2 does not exceed 2 DEG/S.

10. The high-precision centroid inertia measurement method for the small aircraft as claimed in one of claims 6 to 8, wherein the counterweight suspension devices (5, 7, 8, 9) are symmetrically installed on the side of the object to be measured installation plate (1) close to the support upright (4) in a cross distribution manner.

Technical Field

The invention relates to a high-precision mass center inertia measuring system and method for a small aircraft, and belongs to the technical field of aircraft mass center inertia measurement.

Background

In the fields of industrial control and aerospace control, particularly aircrafts and spacecrafts, the mass center and the rotational inertia parameters of a control object have important significance for the design of a control system. Measurements of the primary mass center and moment of inertia are typically made after the aircraft is assembled as important input parameters to the control system. The accurate parameters of the mass center and the rotational inertia are significant for improving the control precision of the aircraft. The traditional method of multi-point weighing is mostly adopted for measuring the mass center, a plurality of force sensors are distributed under a measuring table, the position of the mass center in a plane can be determined by one-time measurement, and for the position of the mass center in a three-dimensional space, the position of a measured object in the space at least needs to be adjusted twice to measure the mass center of the object. The traditional inertia measuring method adopts a torsional pendulum method, a vibration starting device is needed to be used for measuring each time, the platform generates vibration pendulum, the rotational inertia is calculated by measuring the swing period, and the measuring time is long. For some precise objects to be measured, the vibration impact may damage the precise objects to be measured. In addition, in order to measure the rotational inertia matrix of the object, a plurality of postures need to be arranged, and all rotational inertia can be solved through multiple measurements. The method has higher requirements on the transformation of the installation position of the measured object on the platform and the fixing mode of the measured object, and particularly, the fixing mode of the aircraft with special appearance can only provide installation under one posture, so that the installation position cannot be transformed. Another disadvantage is that the traditional method is that the moment of inertia and the mass center measurement are two independent measurement processes, and cannot simultaneously measure, so that the measurement period is long.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: the system comprises a measured object mounting disc, a rate gyro, a spherical bearing, a supporting upright post, a counterweight suspension device, a counterweight mass block and an excitation mass block; the spherical bearing is respectively connected with the supporting upright post and the mounting disc of the measured object; the counterweight suspension device is arranged on one side of the measured object mounting plate close to the supporting upright post; the counterweight mass block is detachably arranged at different positions of the counterweight suspension device; an external object to be measured is placed on the object to be measured mounting plate; the excitation mass block is arranged on the installation disc of the measured object; the rate gyroscope is used for measuring the angular speed and attitude angle of the rotation of the mounting disc of the measured object.

The purpose of the invention is realized by the following technical scheme:

a high-precision mass center inertia measuring system of a small aircraft comprises a measured object mounting disc, a rate gyro, a spherical bearing, a supporting upright post, a counterweight suspension device, a counterweight mass block and an excitation mass block;

the spherical bearing is respectively connected with the supporting upright post and the installation disc of the object to be measured, so that the installation disc of the object to be measured can swing at the spherical center of the spherical bearing; the counterweight suspension device is arranged on one side, close to the supporting upright post, of the installation disc of the measured object; the counterweight mass block is detachably arranged at different positions of the counterweight suspension device; an external object to be measured is placed on the object to be measured mounting plate; the excitation mass block is placed on the installation plate of the measured object;

and the rate gyroscope is used for measuring the rotating angular speed and attitude angle of the mounting disc of the measured object.

Preferably, the spherical bearing is an air-floating spherical bearing or a micro-friction bearing.

Preferably, the counterweight suspension device is symmetrically arranged on one side of the supporting upright column close to the installation disc of the measured object in a cross-shaped distribution manner.

Preferably, the counterweight mass block comprises a plurality of mass blocks with different weight specifications; the mounting position of each mass block on the counterweight suspension device can be adjusted.

Preferably, the excitation mass comprises a plurality of masses of different weight specifications.

A high-precision centroid inertia measurement method of a small aircraft adopts the measurement system, and comprises the following steps:

s1, measuring the mass of the measured object, and then placing the measured object on the measured object mounting plate;

s2, enabling the installation disc of the object to be measured to move freely, and increasing and decreasing counterweight mass blocks on a counterweight suspension device according to the rotation direction of the installation disc of the object to be measured so that the free swinging angular speed of the installation disc of the object to be measured does not exceed 2 degrees/S;

s3, selecting two or four opposite counterweight suspension devices, and adding the same counterweight mass block at the same position on the selected counterweight suspension device to enable the gravity center of the added counterweight mass block to be lower than the spherical center of the spherical bearing;

and S4, placing the excitation mass block on the measured object mounting disc, measuring the rotating angular speed and attitude angle of the measured object mounting disc by using a rate gyroscope, and calculating the mass center and the rotational inertia of the measured object.

Preferably, the weight of the excitation mass in S4 is no more than one tenth of the weight of the object to be measured.

Preferably, the center of mass r of the object to be measured_bComprises the following steps:

wherein m is the total mass including the measured object mounting plate, the rate gyroscope, the counterweight suspension device and the counterweight mass block, r is the mass center of m, m is_aFor measuring the mass of the object mounting plate, r_aIn order to measure the mass center of the object mounting plate, i is a first ordinal number, n is the number of the counterweight mass blocks,

is the mass of the ith counterbalance mass,

is the centroid position of the ith counterweight mass block, m_bThe mass of the object to be measured;

the moment of inertia of the measured object is as follows:

wherein I is the total moment of inertia including the measured object mounting plate, rate gyroscope, counterweight suspension device, counterweight mass block and excitation mass block, I^aI is a first ordinal number, n is the number of the counterweight mass blocks,is the mass of the ith counterbalance mass,

is the position of the mass center of the ith counterweight mass,

is the moment of inertia, m, of the ith counterbalance mass^jFor the mass of the selected excitation mass, r^jFor exciting the centre of mass of the mass, I^jTo excite the moment of inertia of the mass.

Preferably, in S2, the method for increasing or decreasing the counterweight mass on the counterweight suspending device so that the free swing angular velocity of the measured object mounting plate does not exceed 2 °/S includes:

s21, after the installation disc of the object to be measured is rotated to the horizontal position, according to the inclination direction of the installation disc of the object to be measured, the free swinging angular speed of the installation disc of the object to be measured is enabled to be not more than 2 degrees/S by increasing the counterweight mass block and adjusting the position of the counterweight mass block;

s22, inclining the mounting plate of the object to be measured by no more than 25 degrees; according to the movement direction of the mounting disc of the object to be measured, the free swinging angular speed of the mounting disc of the object to be measured is not more than 2 degrees/s by increasing the counterweight mass block and adjusting the position of the counterweight mass block;

s23, repeating the steps S21-S22 until the free swinging angular speed in S2 does not exceed 2 DEG/S.

Preferably, the counterweight suspension device is symmetrically arranged on one side of the supporting upright column close to the installation disc of the measured object in a cross-shaped distribution manner.

Compared with the prior art, the invention has the following beneficial effects:

the method has the advantages that the traditional inertia measuring method needs to generate torsional pendulum vibration according to the vibration principle, and the measuring process of the method has no high-frequency oscillation impact and does not need to be provided with an oscillation starting device, so that the influence of the oscillation impact is reduced. The traditional method for measuring the rotational inertia and the mass center of the three-dimensional space needs to adjust the fixed position of the measured object for multiple times of measurement, and the measurement process cannot be carried out simultaneously.

Drawings

FIG. 1 is a schematic diagram of the composition of the measurement system of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

A high-precision mass center inertia measuring system of a small aircraft comprises a measured object mounting disc 1, a rate gyro 2, a spherical bearing 3, a supporting upright post 4, a counterweight suspension device (5, 7, 8 and 9), a counterweight mass block 6 and an excitation mass block 10. The spherical bearing 3 is respectively connected with the supporting upright post 4 and the installation disc 1 of the object to be measured, so that the installation disc 1 of the object to be measured can swing at the center of the sphere of the spherical bearing 3; the counterweight suspension devices (5, 7, 8 and 9) are arranged on one side, close to the supporting upright post 4, of the installation plate 1 of the object to be measured; the counterweight mass block 6 is detachably arranged at different positions of the counterweight suspension devices (5, 7, 8, 9); an external object to be measured is placed on the object to be measured mounting plate 1; an excitation mass 10 is mounted on the measured object mounting plate 1, and the excitation mass 10 includes a plurality of masses of different weight specifications. The counterweight suspension devices (5, 7, 8 and 9) are symmetrically arranged on one side of the measured object mounting plate 1 close to the supporting upright post 4 in a cross-shaped distribution manner. The counterweight mass 6 comprises a plurality of masses of different weight specifications; the mounting position of each mass on the counterweight suspension device (5, 7, 8, 9) is adjustable. As shown in fig. 1.

A high-precision mass center inertia measuring method for a small aircraft comprises the following specific processes,

the method comprises the following steps: before installation, the mass of the measured object is measured, the friction torque of the spherical bearing 3 is calibrated, and the rotational inertia, the mass and the mass center of the measured object mounting disc 1 are calibrated.

Step two: and after the measured object is arranged on the measured object mounting plate, calibrating the mounting position of the measured object. The method for increasing or decreasing the counterweight mass block 6 on the counterweight suspension device (5, 7, 8, 9) to ensure that the free swing angular velocity of the measured object mounting disc 1 does not exceed 2 DEG/s comprises the following steps:

1) after the installation disc 1 of the object to be measured is rotated to the horizontal position, according to the inclination direction of the installation disc 1 of the object to be measured, the free swinging angular speed of the installation disc 1 of the object to be measured is enabled to be not more than 2 degrees/s by increasing the counterweight mass block 6 and adjusting the position of the counterweight mass block 6;

2) inclining the installation disc 1 of the object to be measured by no more than 25 degrees; according to the movement direction of the mounting disc 1 of the object to be measured, the free swinging angular speed of the mounting disc 1 of the object to be measured is not more than 2 degrees/s by increasing the counterweight mass block 6 and adjusting the position of the counterweight mass block 6; repeating the steps 1) to 2) until the free oscillation angular speed does not exceed 2 degrees/s.

Step three: selecting two or four opposite counterweight suspensions (5, 7, 8, 9), and adding the same counterweight mass block 6 at the same position on the selected counterweight suspension (5, 7, 8, 9), so that the gravity center of the added counterweight mass block 6 is lower than the spherical center of the spherical bearing 3; recording and measuring the mass of all the counterweight mass blocks added in the second step and the third step

Position of center of mass

Step four: and selecting an excitation mass block 10, and placing the excitation mass block 10 on the mounting plate 1 of the object to be tested. The excitation mass 10 acts as an excitation source and the gravitational moment of the excitation mass 10 will cause the platform to rotate. m is^jFor a selected mass of the excitation mass 10, r^jIs the center of mass of the excitation mass 10.

Step five: the platform is kept static at the initial moment, then the platform moves under the action of the gravity moment of the excitation mass block 10, and the angular speed and the attitude angle of the rotation of the measured object mounting disc 1 are measured by using the rate gyroscope 2.

Step six: the total moment of inertia I, m of the platform including the measured object mounting disc 1, the rate gyro 2, the counterweight suspension device (5, 7, 8, 9), the counterweight mass 6 and the excitation mass 10 is the total mass (excluding the excitation mass 10) including the measured object mounting disc 1, the rate gyro 2, the counterweight suspension device (5, 7, 8, 9) and the counterweight mass 6, and r is the mass center of m. The calculation formula is (formula I) to (formula V), whereinTo measure the matrix, r^j×m^jg is measured, and the moment of inertia I and the center of mass r can be obtained by a parameter estimation method. T is_{Friction of}The friction torque of the spherical bearing 3 is calibrated before measurement.

ω＝[ω_xω_yω_z]^T(formula three)

In the formula of omega_xAngular velocity, ω, of the platform about the x-axis_yAngular velocity, ω, of the platform about the y-axis_zAngular velocity, attitude angle of the platform about the z-axis

Theta, psi are the pitch angle, roll angle and yaw angle of the platform, respectively, and g is the gravitational acceleration.

Step seven: calculating the rotational inertia I and the mass center r by a recursive least square method, and then calculating the mass center r of the measured object_bAnd moment of inertia I_bComprises the following steps:

in the formula m_aFor measuring the mass of the object mounting plate 1, r_aMounting the centre of mass, I, of the disk 1 for measuring objects^aI is the moment of inertia of the measured object mounting disc 1, i is a first ordinal number, n is the number of the counterweight mass blocks 6,

is the mass of the ith counterbalance mass,

is the position of the mass center of the ith counterweight mass,

is the moment of inertia, m, of the ith counterbalance mass^jFor a selected mass of the excitation mass 10, r^jFor exciting the center of mass, I, of the mass 10^jTo excite the moment of inertia of the mass 10.

Those skilled in the art will appreciate that those matters not described in detail in the present specification are well known in the art.

Although the present invention has been described with reference to the preferred embodiments, it is not intended to limit the present invention, and those skilled in the art can make variations and modifications of the present invention without departing from the spirit and scope of the present invention by using the methods and technical contents disclosed above.