Device and method for measuring transient mechanical characteristics of storage box under variable gravity working condition

Abstract

The invention relates to the technical field of gravity mechanical property measurement and equipment, and discloses a storage tank variable gravity working condition transient mechanical property measurement device, which comprises an electric rotating device, a gravity sensor and a control device, the electric displacement device controls the position of the storage tank; the rotating device drives the storage box to rotate through the six-axis swinging device so as to randomly change the posture of the storage box; and the six-axis swinging device realizes the posture adjustment of the storage box at a preset angle. The invention further provides a transient mechanical measurement method which is used for studying the variable gravity transient working condition of the preset target and studying the random variable gravity transient working condition. According to the testing device and method, the actual working condition is simulated through multi-dimensional regulation and control, in the measuring process, the rotation angular speed, displacement, stress and the inclination angle before and after the posture change of the storage tank can be accurately measured, therefore, quantitative analysis is conducted on the transient mechanical property of the variable gravity working condition, the limitation of a traditional liquid shaking testing method is overcome, and the testing efficiency is improved. And the method can better adapt to a complex real environment.

Description

Technical Field

[0001] The invention belongs to the technical field of gravity mechanical characteristics measurement and equipment, and specifically relates to a device and method for measuring transient mechanical characteristics of a tank under variable gravity conditions. Background Art

[0002] Liquid sloshing refers to the phenomenon that the free liquid surface of a partially liquid-filled storage cavity moves under the influence of external disturbances. The research on liquid sloshing mainly includes the natural frequency of the liquid, modal vibration type, wave height of the free liquid surface, dynamic sloshing force, sloshing torque and other characteristics. Its behavioral characteristics and sloshing characteristics are affected by complex external conditions (external excitation frequency and amplitude, filling height, etc.), liquid properties, tank geometry and other factors, which brings great difficulties to the analysis of the dynamic characteristics of the liquid in the storage cavity. However, liquid sloshing is a common phenomenon and is widely present in large liquid-filled spacecraft, liquid rockets and other vehicles. Due to the large carrying capacity of liquid energy, when the liquid in the tank sloshes, a large amount of dynamic sloshing force and torque are generated, which will seriously affect the mission execution efficiency, control accuracy and overall stability of the vehicle's control system or control system. Therefore, the research results of liquid sloshing can provide a theoretical basis for the optimization of actual propellant storage equipment and system design, and have important engineering application value.

[0003] At present, the methods for testing liquid sloshing mainly use optical measurement technology (such as particle image velocimetry), non-contact methods (such as installing accelerometers on tanks or containers), numerical simulation technology (computational fluid dynamics), fluid dynamics numerical simulation methods and laser ranging technology, etc. These methods and technologies have some common defects, such as measuring the surface of the liquid or the local flow field, it is difficult to reflect the overall mechanical performance (such as force and torque) under complex multi-dimensional motion, and it is more suitable for measurement under static or simple dynamic conditions. It has poor adaptability to complex three-dimensional motion and transient multiple working conditions, and can only indirectly obtain the impact of sloshing on the container structure, and cannot directly obtain the motion characteristics of the internal liquid. Moreover, these technologies usually work under fixed postures, it is difficult to dynamically adjust the working conditions, and it is impossible to simulate complex gravity and posture changes. They are mostly limited to surface measurements, local flow fields or static conditions, and it is difficult to achieve accuracy and wide applicability under dynamic and complex working conditions. Existing liquid sloshing test experimental devices, such as using ground transport vehicles to simulate the modal state of the tank and measure the transient change of the liquid level, only focus on the liquid level fluctuation and modal change on the horizontal plane, lack flexible control of the direction and magnitude of gravity, and are difficult to simulate the transient force and torque changes that the tank may encounter in a complex motion environment. For another example, application publication number CN119284213A "A space variable gravity fluid tank on-orbit motion simulation experimental device and method" can simulate the working condition of the change of gravity acceleration direction through the rotating mechanism, simulate the working condition of the experimental tank being subjected to low-frequency disturbance through the vibration mechanism, and use a fixed camera and a tracking camera to observe the gas-liquid interface of the experimental tank in three dimensions. However, during the experiment, it is impossible to accurately measure the rotation speed, force and torque of the experimental tank, and thus obtain accurate variable gravity working conditions, so it is necessary to improve the existing technology. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a device and method for measuring transient mechanical characteristics of a variable gravity tank, so as to realize the liquid level change of the tank in different gravity conditions and measure the transient mechanical characteristics of the variable gravity conditions.

[0005] In order to solve the above technical problems, the present invention provides a device for measuring transient mechanical characteristics of a tank under variable gravity conditions, comprising: a rotating platform and a control unit, wherein a central spindle and a linear screw slide module are arranged on the rotating platform, wherein the upper portion of the central spindle is fixedly connected to the center of the rotating platform, and the lower portion is connected through a gear set, a first coupling and a first servo motor;

[0006] The linear screw slide module includes a second servo motor, a linear guide rail and a moving slider, the linear guide rail is arranged along the radial direction of the rotating table and is fixedly connected to the rotating table; a third servo motor and a turbine turntable are arranged on the moving slider, and the third servo motor and the turbine turntable are fixedly connected to the moving slider; a six-axis swing device, a tank clamping device and a tank are arranged above the turbine turntable, the six-axis swing device is fixedly connected to the turbine turntable, and the tank is fixedly connected to the six-axis swing device through the tank clamping device;

[0007] The control unit comprises a displacement sensor, an acceleration sensor, a three-axis inclinometer, a multi-dimensional force sensor and a single-chip microcomputer.

[0008] As an improvement of the device for measuring transient mechanical characteristics of a tank under variable gravity conditions of the present invention:

[0009] The third servo motor is connected to the turbine turntable through a worm gear mechanism;

[0010] The six-axis swing device comprises a fixed platform at the bottom, a telescopic connecting rod in the middle and a moving platform at the top, and the fixed platform is fixedly connected to the turbine turntable.

[0011] As a further improvement of the device for measuring transient mechanical characteristics of a tank under variable gravity conditions of the present invention:

[0012] The tank clamping device comprises a bracket base at the bottom, a supporting bracket in the middle and an annular gripping clamp at the top, and the bracket base is fixedly connected to the moving platform;

[0013] The annular gripping clamp is sleeved on the lower part of the storage tank to clamp and fix the storage tank;

[0014] The central axes of the turbine turntable, the six-axis swing device, the tank clamping device and the tank are colinear with the axis of the central spindle.

[0015] As a further improvement of the device for measuring transient mechanical characteristics of a tank under variable gravity conditions of the present invention:

[0016] The storage tank includes a filling port and a discharge port. The filling port is connected to the three-way valve through a flexible hose after passing through a first one-way valve and a gas-liquid separator in sequence. The discharge port is connected to the three-way valve through a flexible hose after passing through a second one-way valve. Then the three-way valve is connected to the liquid storage tank through a flexible hose after passing through a self-priming pump.

[0017] As a further improvement of the device for measuring transient mechanical characteristics of a tank under variable gravity conditions of the present invention:

[0018] The displacement sensor is arranged on the moving slider, the acceleration sensor and the three-axis inclinometer are arranged on the moving platform, and the acceleration sensor is located at the center of the moving platform; the multi-dimensional force sensor is installed at the bottom center of the tank;

[0019] The displacement sensor, acceleration sensor, three-axis inclinometer, multi-dimensional force sensor and single-chip microcomputer are all connected by signal; the single-chip microcomputer is respectively connected by signal with the first servo motor, the second servo motor, the third servo motor, the stepping motor of the six-axis swing device and the self-priming pump.

[0020] The present invention also provides a method for transient mechanical measurement using the above-mentioned device for measuring transient mechanical characteristics of a tank under variable gravity conditions, comprising the following steps:

[0021] S1, initialization device: add liquid into the tank so that the mass of the tank reaches m after the liquid is added, and adjust the tank to a vertical state;

[0022] S2, the moving slider translates along the linear guide rail, and when the displacement sensor measures the displacement of the tank as R, the tank reaches the target position;

[0023] S3, variable gravity transient working condition of preset target

[0024] S3.1. Determine the variable gravity transient working condition target by constructing an equivalent gravity model of the variable gravity working condition transient mechanical characteristics measuring device;

[0025] S3.2, start the rotating table, when the acceleration sensor measures the centripetal acceleration When the rotating table enters the uniform rotation state, the tank obtains the target rotation angular velocity ;

[0026] S3.3, quantitatively adjust the telescopic length of each telescopic link of the six-axis swing device to drive the attitude of the tank to change transiently to achieve the target of variable gravity transient working condition;

[0027] S3.4, a multi-dimensional force sensor detects the force applied during the tank posture change process, and a three-axis inclinometer detects the tilt angle during the tank posture change process;

[0028] S4, Random variable gravity transient condition

[0029] S4.1, the rotating table rotates at a constant speed;

[0030] S4.2. Each telescopic link of the six-axis swing device is in a free adjustment state; the turbine turntable rotates at a random rotation angle, so that each telescopic link of the six-axis swing device randomly extends and retracts the length, driving the attitude of the tank to undergo random transient changes;

[0031] S4.3. The tilt angle of the tank during each posture change is monitored in real time by a three-axis inclinometer, the force applied to the tank during each posture change is monitored in real time by a multi-dimensional force sensor, and the rotational angular velocity ω of the tank during each posture change is monitored in real time by an acceleration sensor.

[0032] As an improvement of the transient mechanical measurement method of the present invention:

[0033] The equivalent gravity model is:

[0034] (1)

[0035] in, is the gravitational acceleration of the tank’s initial attitude, is the gravity acceleration after variable gravity condition, ω is the rotation angular velocity of the tank, is the angle between the tank centerline and the X-axis, It is the angle between the center axis of the tank and the Z axis.

[0036] As a further improvement of the transient mechanical measurement method of the present invention:

[0037] The variable gravity transient operating conditions target is:

[0038] When the angle between the tank centerline and the X-axis is the target value , the angle between the tank centerline and the Z axis is the target value When the force on the tank in the x-axis direction reaches the preset target , the force in the z-axis direction reaches the preset target :

[0039] (2)

[0040] (3)

[0041] in, is the target value of the gravity component in the x-axis direction after the variable gravity transient condition, It is the target value of the gravity component in the z-axis direction after the variable gravity transient condition.

[0042] As a further improvement of the transient mechanical measurement method of the present invention:

[0043] The target value , target value They are:

[0044] (4)

[0045] (5)

[0046] (6)

[0047] in, is the target centripetal acceleration, is the target rotation angular velocity.

[0048] The beneficial effects of the present invention are mainly reflected in:

[0049] 1. The present invention changes the centripetal acceleration by changing the rotation speed through an electric rotating device, changes the displacement value of the tank on the rotating table through an electric translation device, and adjusts the tilt angle of the tank by changing the motion posture of the tank through a slewing device and a six-axis swing device, so that the tank changes from the initial state of gravity working condition to another working condition within a transient time, thereby achieving the purpose of variable gravity, and then measuring the transient force and torque values ​​of the tank under the variable gravity working condition, which can better simulate the working conditions of the tank under actual complex conditions.

[0050] 2. The testing device and method of the present invention simulate actual working conditions through multi-dimensional control and directly measure force and torque, thus overcoming the limitations of traditional liquid sloshing testing methods and being more adaptable to complex real-world environments.

[0051] 3. During the measurement process, the testing device and method of the present invention can accurately measure the rotational angular velocity, displacement, force and tilt angle of the tank before and after the posture change, thereby quantitatively analyzing the transient mechanical characteristics of the variable gravity working condition.

[0052] 4. The testing device and method of the present invention can realize the research on random variable gravity transient working conditions and the research on variable gravity transient working conditions with preset targets, which is more flexible and scientific. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] The specific implementation modes of the present invention are further described in detail below with reference to the accompanying drawings.

[0054] Figure 1 It is a structural schematic diagram of a device for measuring transient mechanical characteristics of a tank under variable gravity conditions according to the present invention;

[0055] Figure 2 It is a structural schematic diagram of the tank clamping device of the present invention;

[0056] Figure 3 It is a schematic diagram of the structure of the rotary device of the present invention;

[0057] Figure 4 Transient force curve of variable gravity transient working condition experiment for preset target;

[0058] Figure 5 It is the transient force curve of the random variable gravity transient working condition experiment. DETAILED DESCRIPTION

[0059] The present invention is further described below in conjunction with specific embodiments, but the protection scope of the present invention is not limited thereto:

[0060] Embodiment 1, a device for measuring transient mechanical characteristics of a tank under variable gravity conditions, such as Figure 1As shown, it includes an electric rotating device, an electric displacement device, a slewing device, a six-axis swing device 40, a tank clamping device 50, a tank 8, a liquid circulation device and a control unit.

[0061] The electric rotating device is mainly composed of a first servo motor 11, a first coupling 12, a base 1, a rotating table 13 and a central spindle. The base 1 is used for the stability and support of the entire device. The first servo motor 11 is located on one side of the base 1, and the rotating table 13 is located on the base 1. Both are adjacent to the base 1 but not connected. A vertical central spindle is provided at the center of the rotating table 13. The upper part of the central spindle is fixedly connected to the rotating table 13, and the lower part is connected by a gear set, a first coupling 12 and a first servo motor 11, so that the first servo motor 11 can drive the rotating table 13 to rotate and start and stop on a horizontal plane to obtain a centripetal acceleration.

[0062] On the rotating table 13, an electric displacement device, a rotation device, a six-axis swing device 40 and a tank clamping device 50 are arranged in sequence from bottom to top. The tank clamping device 50 is sleeved on the lower part of the tank 8 to fix the tank 8.

[0063] The electric displacement device includes a linear screw slide module, which is arranged along the radial direction of the rotating table 13 and fixedly connected to the top surface of the rotating table 13 by bolts. The linear screw slide module can be purchased from the market, for example, the FSL series ball screw linear module of Chengdu Fuyu Technology Co., Ltd. can be used. The linear screw slide module includes a second servo motor 21, a ball screw 22, a linear guide 24 and a moving slider 25. The second servo motor 21 drives the ball screw 22 to rotate, so that the moving slider 25 performs reciprocating linear motion on the linear guide 24 (i.e., moves along the radial direction of the rotating table 13). The second servo motor 21 is also equipped with an electromagnetic brake device, which realizes the stopping and self-locking of the moving slider 25 during the translation process by changing the control signal of the motor and the electromagnetic brake device inside the motor.

[0064] The rotating device includes a third servo motor 31 and a turbine turntable 32. The third servo motor 31 and the turbine turntable 32 are both arranged on the moving slider 25, and the third servo motor 31 and the turbine turntable 32 are both fixedly connected to the moving slider 25. Figure 3 The third servo motor 31 is connected to the turbine turntable 32 through a worm gear mechanism, thereby driving the turbine turntable 32 to rotate on the horizontal plane, and changing the motion posture of the six-axis swing device 40 installed on the turbine turntable 32 through the rotary motion.

[0065] The six-axis swing device 40 includes a fixed platform at the bottom, six telescopic connecting rods in the middle and a moving platform at the top. The two ends of the telescopic connecting rod are fixedly connected to the fixed platform and the moving platform respectively. The six-axis swing device 40 can be obtained by commercial purchase or customization, for example, using the six-degree-of-freedom electric motion system of the ZY-PE series of Hangzhou Guochen Zhengyu Technology Co., Ltd. The fixed platform of the six-axis swing device 40 is fixed to the turbine turntable 32 through a flange. This connection method ensures that the six-axis swing device 40 can rotate with the rotating device, and can withstand various forces and motion inertia, maintaining the stability of the six-axis swing device 40 and the uniformity of force distribution. The six telescopic links of the six-axis swing device 40 are all equipped with stepper motors, and have two working states: one is that the stepper motors are controlled by the single-chip microcomputer to quantitatively adjust the telescopic lengths of the telescopic links respectively, so that the moving platform tilts at a preset angle; the other is that the stepper motor is not working, the telescopic links are in a free telescopic state, and the centrifugal force of the rotation of the turbine turntable 32 drives the telescopic links to randomly extend or shorten each other, so that the moving platform tilts at a random angle, so as to study the mechanical characteristics of the variable gravity working conditions of the tank under different tilt angles.

[0066] The tank clamping device 50 includes a support base 53 at the bottom, a support bracket 52 in the middle, and an annular clamp 51 at the top. The upper and lower ends of the support bracket 52 are fixedly connected to the annular clamp 51 and the support base 53. Figure 2 As shown. The tank 8 is a cylindrical shape with a small bottom and a large top. The annular clamp 51 is sleeved on the lower part of the tank 8. The inner ring of the annular clamp 51 is provided with a flexible pad to increase the friction force to fix the tank 8. Since the diameter of the lower part of the tank 8 is slightly smaller than the diameter of the upper part, the lower part of the tank 8 is clamped and fixed in the annular clamp 51 by gravity. The bracket base 53 is fixed to the moving platform of the six-axis swing device 40 by bolts. The central axis of the turbine turntable 32, the six-axis swing device 40, the tank clamping device 50 and the tank 8 is in the same straight line as the axis of the central main shaft, so that the tank 8 can change its posture together with the six-axis swing device 40. At the same time, the rotating table 13 is used to drive the tank 8 to rotate at a uniform speed on the horizontal plane, and the linear screw slide module is used to drive the tank 8 to move back and forth in a straight line.

[0067] The upper part of the storage tank 8 is provided with a filling port, and the bottom part is provided with a liquid discharge port. The liquid circulation device comprises a self-priming pump 86, a three-way valve 84, a gas-liquid separator 82 and a liquid storage tank 9. The filling port is connected to the three-way valve 84 after passing through the first one-way valve 83 and the gas-liquid separator 82 in sequence through a flexible hose 87, and the liquid discharge port is connected to the second one-way valve 85 and the three-way valve 84 in sequence through a flexible hose 87, and then the three-way valve 84 is connected to the self-priming pump 86 and the liquid storage tank 9 in sequence through the flexible hose 87. When the self-priming pump 86 rotates forward, the first one-way valve 83 is in a conducting state, and the second one-way valve 85 is in a closed state. The liquid in the liquid storage tank 9 is injected into the storage tank 8 through the self-priming pump 86, the three-way valve 84, the first one-way valve 83 and the gas-liquid separator 82. The gas-liquid separator 82 is used to remove the gas in the filling liquid and ensure the smooth progress of the liquid injection process.

[0068] When the liquid in the storage tank 8 needs to be discharged, the self-priming pump 86 reverses, the first one-way valve 83 is in a cut-off state, the second one-way valve 85 is in a conducting state, and the liquid in the storage tank 8 flows back to the liquid storage tank 9 through the second one-way valve 85, the three-way valve 84, and the self-priming pump 86.

[0069] The filling port, the gas-liquid separator 82, the first one-way valve 83, the three-way valve 84, the discharge port, the second one-way valve 85, the self-priming pump 86, and the liquid storage tank 9 are all connected to each other by a flexible hose 87, and are all quickly disassembled and connected by a snap-on quick connector or a threaded connection. During the experiment, the flexible hose 87 between the storage tank 8 and the liquid circulation device is removed so that the storage tank 8 is not restricted by the flexible hose 87 during rotation and movement and can move freely.

[0070] The control unit includes a displacement sensor 61, an acceleration sensor 62, a three-axis inclinometer 63 and a single-chip microcomputer; the displacement sensor 61 is arranged on the moving slider 25 and is fixedly connected to the moving slider 25. When the moving slider 25 reciprocates on the linear guide rail 24, the displacement measured by the displacement sensor 61 is equivalent to the displacement of the tank 8. The acceleration sensor 62 and the three-axis inclinometer 63 are both arranged on the moving platform. The acceleration sensor 62 is located on the axis of the six-axis swing device 40 (i.e., the center of the moving platform of the six-axis swing device 40), and is used to measure the centripetal acceleration of the tank 8 when the rotating table 13 and the turbine turntable 32 rotate at a uniform speed. The three-axis inclinometer 63 is located at any position on the moving platform of the six-axis swing device 40, and is used to measure the inclination angle of the tank 8 as the six-axis swing device 40 deflects. The acceleration sensor 62 and the three-axis inclinometer 63 are both fixedly connected to the moving platform.

[0071] The single chip microcomputer is signal-connected to the first servo motor 11 , the second servo motor 21 , the third servo motor 31 , and the self-priming pump 86 to control the start and stop and speed of the first servo motor 11 , the second servo motor 21 , the third servo motor 31 , and the self-priming pump 86 .

[0072] A multi-dimensional force sensor is installed at the bottom center of the tank 8 to measure the force generated during the experiment. and torque value And the weight of the tank 8 after filling with liquid. The multi-dimensional force sensor is connected with the single chip microcomputer signal to transmit the measured data.

[0073] The single chip microcomputer is connected to the host computer by signals to transmit the data collected by the displacement sensor 61, the acceleration sensor 62, the three-axis inclinometer 63 and the multi-dimensional force sensor to the host computer, and receive the instructions of the host computer.

[0074] The implementation principle of the device for measuring transient mechanical characteristics under gravity conditions of the present invention is specifically as follows:

[0075] 1. The electric rotating device provides a variable speed to the rotating table 13, thereby achieving the condition of variable acceleration;

[0076] 2. The electric displacement device controls the position of the movable slider 25, and the displacement of the storage tank 8 is measured by the displacement sensor 61;

[0077] 3. The rotary device drives the six-axis swing device 40 to perform a rotary motion, thereby changing the length of each telescopic connecting rod of the six-axis swing device 40 to achieve random tilting of the storage tank 8;

[0078] The stepping motors of the six-axis swing device 40 quantitatively adjust the telescopic length of the telescopic connecting rods respectively, so that the dynamic storage tank 8 is tilted at a preset angle;

[0079] 4. The adjustment range of the angle between the axis of the tank 8 and the X-axis and the Y-axis after the posture is changed is , the adjustment range of the angle with the Z axis is ;because Axis and The rotation parameters of the shaft rotation are basically the same. To simplify the test workload, during the experiment in which the tank 8 is placed vertically, only Axis and Axis rotation experiment;

[0080] 5. When the six-axis swing device 40 is in the initial posture (the tank 8 is along the The gravitational acceleration when the axis is placed vertically is When the posture of the tank 8 changes (i.e., the variable gravity condition), the gravity component on each axis will also change accordingly. At this time, it can be considered that the gravity component on each axis after the posture of the tank 8 changes is obtained after the initial component rotates around the axis. According to the gravity component of the initial posture and the gravity component after the posture change (i.e., the variable gravity condition), the inclination angle of each axis of the tank 8 from the initial posture to the variable gravity condition is solved, which is used as the input data of the six-axis swing device 40 to achieve the purpose of variable gravity.

[0081] The method for performing transient mechanical measurement using the device for measuring transient mechanical characteristics of a tank under variable gravity conditions of the present invention is specifically as follows: 1. The equivalent gravity model of the device for measuring transient mechanical characteristics of tank under variable gravity conditions is:

[0082] (1)

[0083] in, is the gravitational acceleration of the initial posture of the tank 8, is the gravity acceleration after the variable gravity condition, ω is the rotation angular velocity of the tank 8, is the angle between the central axis of the tank 8 and the X axis, is the angle between the center axis of the tank 8 and the Z axis, R is the displacement of the tank 8, Take values ​​within the range of

[0084] 2. Study on transient working conditions of variable gravity with preset targets

[0085] 2.1. Setting variable gravity transient working condition targets:

[0086] (1) After the gravity changes in the transient state, the preset target force in the x-axis direction is , the preset target force in the z-axis direction is :

[0087] (2)

[0088] (3)

[0089] Wherein, m is the mass of the tank 8 after being filled with liquid, which is measured by the multi-dimensional force sensor; is the target value of the gravity component in the x-axis direction after the variable gravity transient condition, It is the target value of the gravity component in the z-axis direction after the variable gravity transient condition.

[0090] (2) When the displacement of the tank 8 is preset to R, the target inclination angle after the variable gravity transient condition (including the angle between the center axis of the tank 8 and the X-axis) , Angle between the center axis of tank 8 and Z axis )for:

[0091] (4)

[0092] (5)

[0093] in, is the target rotation angular velocity:

[0094] (6)

[0095] in, is the target centripetal acceleration;

[0096] (3) The target of variable gravity transient condition is:

[0097] The distance between the tank 8 and the center of the rotating platform 13 is R, and the target rotation angular velocity is When rotating at a constant speed, when the angle between the center axis of the tank 8 and the X axis is the target value , the angle between the center axis of the tank 8 and the Z axis is the target value When the force on the tank 8 in the x-axis direction reaches the preset target , the force in the z-axis direction reaches the preset target , thereby achieving the purpose of variable gravity.

[0098] 2.2. Implementation process of variable gravity transient working condition

[0099] 2.2.1. Initialize the device

[0100] Fill the tank 8 with liquid through the liquid circulation device so that the mass of the tank 8 reaches m after the liquid is filled; then disconnect the flexible hose 87 from the drain port and the filling port;

[0101] The switches of the multi-dimensional force sensor, the displacement sensor 61, the acceleration sensor 63 and the three-axis angle calibrator 62 are turned on, and the posture of the six-axis swing device 40 is reset and adjusted so that the tank 8 is in the initial state, that is, the vertical state.

[0102] 2.2.2. Tank 8 moves to target position

[0103] The second servo motor 21 is started, and the moving slider 25 moves along the linear guide rail 24 . When the displacement of the tank 8 is measured to be R by the displacement sensor 61 , the tank 8 reaches the target position, and the second servo motor 21 locks the position of the moving slider 25 .

[0104] 2.2.3. The tank 8 rotates at the target angular velocity Uniform rotation

[0105] The first servo motor 11 is started, the rotating platform 13 starts to rotate, and the centripetal acceleration is measured by the acceleration sensor 62. When the rotating platform 13 enters a uniform rotation state, the tank 8 obtains the target rotation angular velocity .

[0106] 2.2.4. Start the six-axis swing device 40. The stepping motor of the six-axis swing device 40 quantitatively adjusts the telescopic length of each telescopic link so that the moving platform changes its posture and the tank 8 tilts toward the target angle (preset by formula (5)). Value, formula (4) preset value) tilted.

[0107] 2.2.5. The tilt angle of the tank 8 during the posture change is monitored in real time by the three-axis inclinometer 63, and the force applied to the tank 8 during the posture change is monitored in real time by the multi-dimensional force sensor, including the force applied in the x-axis direction. and the force in the z-axis direction .

[0108] 2.2.6. When the angle between the center axis of the tank 8 and the X axis is equal to the preset angle of formula (5): The value, the angle between the central axis of the tank 8 and the Z axis is equal to the preset value of formula (4). value, the attitude of the tank 8 is adjusted to the target position, achieving the gravity target after the variable gravity transient condition and At this time (when the posture of the tank 8 is adjusted to the target position) The value should be equal to or close to the preset target , similarly, The value should be equal to or close to the preset target .

[0109] 3. Study on transient working conditions of random variable gravity

[0110] 3.1. Objectives of the transient working condition of random variable gravity: The slewing device randomly rotates to measure the transient forces and moments during the change of the attitude of the tank 8;

[0111] 3.2. Implementation process of random variable gravity transient working condition

[0112] 3.2.1. Initialize the device, same as step 2.2.1.

[0113] 3.2.2. The tank 8 is moved to the target position, as in step 2.2.2.

[0114] 3.2.3. Start the first servo motor 11, and the rotating platform 13 starts to rotate and enters a uniform speed rotation state.

[0115] 3.2.4. The six-axis swing device 40 is closed, and each telescopic connecting rod of the six-axis swing device 40 is in a free adjustment state;

[0116] The third servo motor 31 is started, and the turbine turntable 32 rotates at a random rotation angle. The rotation of the turbine turntable 32 drives the six-axis swing device 40 to perform a rotary motion. Each telescopic link of the six-axis swing device 40 randomly extends and retracts its length to change the posture of the moving platform.

[0117] 3.2.5. The tilt angle of the tank 8 during each posture change is monitored in real time by the three-axis inclinometer 63, and the force applied to the tank 8 during each posture change is monitored in real time by the multi-dimensional force sensor, including the force applied in the x-axis direction. and the force in the z-axis direction The centripetal acceleration of the tank 8 is measured by the acceleration sensor 62 to obtain the rotational angular velocity ω, which is used for the study of random variable gravity transient working conditions.

[0118] experiment:

[0119] The effectiveness of the present invention is verified by simulating a device and method for measuring transient mechanical characteristics of a tank under variable gravity conditions proposed in Example 1 in a laboratory environment.

[0120] The volume of the storage tank 8 used in the experimental device is , the total weight after filling with liquid is , the initial state of the tank 8 is in a vertical state, and the gravity component of the initial posture is .

[0121] (1) Variable gravity transient condition experiment with preset targets

[0122] The experiment presets five sets of variable gravity transient working condition targets, as shown in Table 1.

[0123] Table 1. Preset targets for variable gravity transient conditions

[0124] The rotating table 13 rotates at a target angular velocity After the uniform rotation, the multi-dimensional force sensor continuously outputs the force of the tank 8 during the movement in real time. The force results of the tank 8 after the posture change measured based on the preset target in Table 1 are shown in Table 2.

[0125] Table 2. Comparison of the force after the tank posture changes and the target force

[0126] From Table 1 and Table 2, we can see that the force output by the multi-dimensional force sensor is With preset goals between, With preset goals The error between them is within ±2%, and by determining each group of adjustable parameters, including the rotation angular velocity of the rotating table 13 When the tank 8 changes its posture, the included angle α between the axis and the X axis and the included angle γ between the axis and the Z axis can stably obtain the preset target and preset goals , reaching the preset target of gravity component after attitude change and .

[0127] The device has significant advantages in measuring the force and torque characteristics of the tank 8 under variable gravity conditions. Through the combination of the electric displacement device, the rotation device, and the six-axis swing device 40, the device of the present invention can comprehensively measure the transient force and torque characteristics of the tank 8 under different gravity conditions and postures. This not only simulates a complex space environment, but also can accurately adjust the tilt angle and acceleration of the tank 8, thereby obtaining data with more reference value in practical applications.

[0128] In contrast, the traditional ground transport vehicle tank test device only focuses on the level fluctuation and modal changes on the horizontal plane, and fails to consider the influence of gravity field changes, so it cannot accurately reflect the response characteristics of the tank in multi-dimensional postures and different gravity environments. In addition, due to the lack of flexible control of the direction and magnitude of gravity, it is difficult to simulate the transient force and torque changes that the tank may encounter in a complex motion environment, which limits the applicability of experimental data in a wider range of engineering applications.

[0129] (2) Visual output of variable gravity transient condition experiment with preset target

[0130] When the preset target , preset goals When the tank 8 changes its posture, the preset value of the angle between the central axis of the tank 8 and the X axis is , the preset value of the angle between the central axis of the tank 8 and the Z axis The tilt angle of the dynamic platform of the six-axis swing device 40 is precisely controlled by the single-chip microcomputer. The transient force curve during the variable gravity transient working condition is as follows: Figure 4 shown.

[0131] (3) Visualization output of random variable gravity transient condition experiment

[0132] The speed of the turbine turntable 32 is 2 rad / s, and the speed of the rotating table 13 is 4.5 rad / s, which is used to drive the tilt angle of the moving platform of the six-axis swing device 40 to change. The transient force curve during the variable gravity transient working condition is as follows: Figure 5 As shown, after the tank 8 changes its posture , .

[0133] pass Figure 4 and Figure 5 It can be seen that during the rotation of the storage tank 8, the forces generated by the x-axis and the z-axis are gradually decreasing. This is because the liquid inside the storage tank 8 shakes when it starts to rotate, and finally as the rotation ends, the internal liquid gradually becomes flat, causing the force to gradually decrease and finally become flat.

[0134] Finally, it should be noted that the above examples are only some specific embodiments of the present invention. Obviously, the present invention is not limited to the above embodiments, and there are many variations. All variations that can be directly derived or associated with the content disclosed by a person skilled in the art should be considered as the protection scope of the present invention.

Claims

1. A device for measuring transient mechanical characteristics of a tank under variable gravity conditions, characterized in that: It comprises a rotating platform (13) and a control unit. A central spindle and a linear screw slide module are arranged on the rotating platform (13). The upper part of the central spindle is fixedly connected to the center of the rotating platform (13), and the lower part is transmission-connected via a gear set, a first coupling (12) and a first servo motor (11). The linear screw slide module comprises a second servo motor (21), a linear guide rail (24) and a movable slider (25), wherein the linear guide rail (24) is arranged along the radial direction of the rotating platform (13) and is fixedly connected to the rotating platform (13); a third servo motor (31) and a turbine turntable (32) are arranged on the movable slider (25), and the third servo motor (31) and the turbine turntable (32) are both fixedly connected to the movable slider (25); a six-axis swing device (40), a tank clamping device (50) and a tank (8) are arranged above the turbine turntable (32), the six-axis swing device (40) is fixedly connected to the turbine turntable (32), and the tank (8) is fixedly connected to the six-axis swing device (40) through the tank clamping device (50); The control unit comprises a displacement sensor (61), an acceleration sensor (62), a three-axis inclinometer (63), a multi-dimensional force sensor and a single-chip microcomputer.

2. The device for measuring transient mechanical characteristics of a tank under variable gravity conditions according to claim 1, characterized in that: The third servo motor (31) is transmission-connected to the turbine turntable (32) via a worm gear mechanism; The six-axis swing device (40) comprises a fixed platform at the bottom, a telescopic connecting rod in the middle and a movable platform at the top, and the fixed platform is fixedly connected to the turbine turntable (32).

3. The device for measuring transient mechanical characteristics of a tank under variable gravity conditions according to claim 2, characterized in that: The tank clamping device (50) comprises a lower support base (53), a middle support bracket (52) and an upper annular gripping clamp (51), and the support base (53) is fixedly connected to the moving platform; The annular gripping clamp (51) is sleeved on the lower part of the storage box (8) to clamp and fix the storage box (8); The central axes of the turbine turntable (32), the six-axis swing device (40), the tank clamping device (50) and the tank (8) are colinear with the axis of the central main shaft.

4. The device for measuring transient mechanical characteristics of a tank under variable gravity conditions according to claim 3, characterized in that: The storage tank (8) comprises a filling port and a liquid discharge port. The filling port is connected to a three-way valve (84) through a flexible hose (87) and passes through a first one-way valve (83) and a gas-liquid separator (82) in sequence. The liquid discharge port is connected to a three-way valve (84) through a flexible hose (87) and passes through a second one-way valve (85). Then, the three-way valve (84) is connected to a liquid storage tank (9) through a flexible hose (87) and passes through a self-priming pump (86).

5. The device for measuring transient mechanical characteristics of a tank under variable gravity conditions according to claim 4, characterized in that: The displacement sensor (61) is arranged on the moving slider (25), the acceleration sensor (62) and the three-axis inclinometer (63) are both arranged on the moving platform, and the acceleration sensor (62) is located at the center of the moving platform; the multi-dimensional force sensor is installed at the bottom center of the tank (8); The displacement sensor (61), the acceleration sensor (62), the three-axis inclinometer (63), and the multi-dimensional force sensor are all signal-connected to the single-chip microcomputer; the single-chip microcomputer is signal-connected to the first servo motor (11), the second servo motor (21), the third servo motor (31), the stepping motor of the six-axis swing device (40), and the self-priming pump (86).

6. A method for measuring transient mechanical properties of a tank under variable gravity conditions using the device for measuring transient mechanical properties of a tank under variable gravity conditions as claimed in any one of claims 1 to 5, characterized in that The steps include: S1, initialization device: filling liquid into the storage tank (8) so that the mass of the storage tank (8) reaches m after the filling, and adjusting the storage tank (8) to a vertical state; S2, the moving slider (25) moves along the linear guide rail (24), and when the displacement sensor (61) measures that the displacement of the storage tank (8) is R, the storage tank (8) reaches the target position; S3, variable gravity transient working condition of preset target S3.

1. Determine the variable gravity transient working condition target by constructing an equivalent gravity model of the variable gravity working condition transient mechanical characteristics measuring device; S3.2, start the rotating platform (13), when the acceleration sensor (62) measures the centripetal acceleration When the rotating platform (13) enters a uniform rotation state, the tank (8) obtains the target rotation angular velocity ; S3.3, quantitatively adjusting the telescopic length of each telescopic link of the six-axis swing device (40), driving the attitude of the tank (8) to undergo a transient change to achieve the target of a variable gravity transient working condition; S3.4, a multi-dimensional force sensor detects the force applied to the tank (8) during the posture change process, and a three-axis inclinometer (63) detects the tilt angle of the tank (8) during the posture change process; S4, Random variable gravity transient condition S4.1, the rotating table (13) rotates at a constant speed; S4.2, each telescopic link of the six-axis swing device (40) is in a free adjustment state; the turbine turntable (32) rotates at a random rotation angle, so that each telescopic link of the six-axis swing device (40) is randomly extended and retracted, driving the posture of the tank (8) to undergo random transient changes; S4.

3. The tilt angle of the tank (8) during each posture change is monitored in real time by a three-axis inclinometer (63), the force applied to the tank (8) during each posture change is monitored in real time by a multi-dimensional force sensor, and the rotational angular velocity ω of the tank (8) during each posture change is monitored in real time by an acceleration sensor (62).

7. The method for transient mechanical measurement according to claim 6, characterized in that: The equivalent gravity model is: （1） in, is the gravitational acceleration of the tank (8) at its initial position, is the gravitational acceleration after the variable gravity condition, ω is the rotational angular velocity of the tank (8), is the angle between the center axis of the tank (8) and the X-axis, It is the angle between the center axis of the tank (8) and the Z axis.

8. The method for transient mechanical measurement according to claim 7, characterized in that: The variable gravity transient operating conditions target is: When the angle between the center axis of the tank (8) and the X-axis is the target value , the angle between the center axis of the tank (8) and the Z axis is the target value When the force on the tank (8) in the x-axis direction reaches the preset target , the force in the z-axis direction reaches the preset target : （2） （3） in, is the target value of the gravity component in the x-axis direction after the variable gravity transient condition, It is the target value of the gravity component in the z-axis direction after the variable gravity transient condition.

9. The method for transient mechanical measurement according to claim 8, characterized in that: The target value , target value They are: （4） （5） （6） in, is the target centripetal acceleration, is the target rotation angular velocity.

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