Device and Method for Measuring Transient Mechanical Characteristics of a Storage Tank under Variable Gravity Conditions

Abstract

The present invention relates to the technical field of determination of gravitational mechanical properties and equipment, and discloses a device for measuring the transient mechanical properties of a storage tank under variable gravity conditions, including an electric rotating device for providing a variable rotational speed for the storage tank; an electric displacement device for controlling the position of the storage tank; a slewing device for driving the storage tank to perform a slewing motion through a six-axis swing device to randomly change the attitude of the storage tank; and a six-axis swing device for realizing the attitude adjustment of the storage tank at a predetermined angle. The present invention also simultaneously provides a method for transient mechanical measurement, which is used for the research on the variable gravity transient conditions of a preset target and the research on the randomly variable gravity transient conditions. The test device and method of the present invention simulate the actual conditions through multi-dimensional regulation. During the measurement process, the rotational angular velocity, displacement, force, and tilt angle before and after the change in the attitude of the storage tank can be accurately measured, so as to quantitatively analyze the transient mechanical properties under variable gravity conditions, overcome the limitations of traditional liquid sloshing test methods, and be more adaptable to complex real environments.

Description

Technical Field

[0001] The present invention belongs to the technical field of determination of gravitational mechanical properties and equipment, and specifically relates to a device and method for determining the transient mechanical properties of a liquid storage tank under variable gravity conditions. Background Technique

[0002] Liquid sloshing refers to the phenomenon that the free liquid surface moves under the action of external disturbances in a partially filled liquid storage cavity. The research on liquid sloshing mainly includes characteristics such as the natural frequency of the liquid, modal vibration modes, wave height of the free liquid surface, dynamic sloshing force, and sloshing torque. Its behavioral characteristics and sloshing characteristics are affected by external complex working conditions (external excitation frequency and amplitude, liquid filling height, etc.), liquid properties, geometric shape of the storage tank, etc. This brings great difficulties to the analysis of the dynamic characteristics of the liquid in the storage cavity. However, the problem of liquid sloshing is a common phenomenon and widely exists in large liquid-filled spacecraft, liquid rockets and other carriers. Since the storage capacity of liquid energy is relatively large, when the liquid in the storage tank sloshes, a large amount of dynamic sloshing force and torque will seriously affect the task execution efficiency, control accuracy and overall stability of the carrier's control system or control system. Therefore, the research results of liquid sloshing can provide a theoretical basis for the design optimization of actual propellant storage equipment and systems, 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 are all signal-connected to the single-chip microcomputer; the single-chip microcomputer is respectively signal-connected to 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 simultaneously provides a method for transient mechanics measurement using the above-mentioned transient mechanics characteristic measurement device for a storage tank under variable gravity conditions, including the following steps:

[0021] S1. Initialize the device: Fill the storage tank with liquid so that the mass of the storage tank reaches m after filling, and adjust the storage tank to the vertical state;

[0022] S2. Move the slider to translate along the linear guide rail. When the displacement sensor measures the displacement of the storage tank as R, the storage tank reaches the target position;

[0023] S3. Preset the target variable gravity transient condition

[0024] S3.1. By constructing an equivalent gravity model of the transient mechanics characteristic measurement device for variable gravity conditions, determine the target of the variable gravity transient condition;

[0025] S3.2. Start the rotating table. When the acceleration sensor measures the centripetal acceleration as When, the rotating table enters the uniform rotation state, and the storage tank obtains the target rotational angular velocity ;

[0026] S3.3. Quantitatively adjust the telescopic lengths of the telescopic links of the six-axis swing device to drive the attitude of the storage tank to change transiently to achieve the target of the variable gravity transient condition;

[0027] S3.4. The multi-dimensional force sensor detects the force during the attitude change of the storage tank, and the three-axis inclinometer detects the tilt angle during the attitude change of the storage tank;

[0028] S4. Random variable gravity transient condition

[0029] S4.1. The rotating table rotates uniformly;

[0030] S4.2. The telescopic links of the six-axis swing device are in the free adjustment state; the turbine turntable rotates by a random rotation angle, so that the telescopic links of the six-axis swing device randomly extend and contract in length, driving the attitude of the storage tank to change randomly and transiently;

[0031] S4.3. Real-time monitor the tilt angle during each attitude change of the storage tank through the three-axis inclinometer, real-time monitor the force during each attitude change of the storage tank through the multi-dimensional force sensor, and real-time monitor the rotational angular velocity ω during each attitude change of the storage tank through the acceleration sensor.

[0032] Improvement to the method for transient mechanics measurement of the present invention:

[0033] The equivalent gravity model is:

[0034] (1)

[0035] Wherein, is the gravitational acceleration of the initial attitude of the storage tank, is the gravitational acceleration after the variable gravity working condition, ω is the rotational angular velocity of the storage tank, is the angle between the central axis of the storage tank and the X-axis, is the angle between the central axis of the storage tank and the Z-axis.

[0036] Further improvement to the method for transient mechanics measurement of the present invention:

[0037] The target of the variable gravity transient working condition is:

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

[0039] (2)

[0040] (3)

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

[0042] Further improvement to the method for transient mechanics measurement of the present invention:

[0043] The target value and the target value are respectively:

[0044] (4)

[0045] (5)

[0046] (6)

[0047] Wherein, is the target centripetal acceleration, is the target rotational 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 rotational speed through an electric rotating device, changes the displacement value of the storage tank on the rotating table through an electric translation device, and changes the motion posture of the storage tank through a slewing device and a six-axis swing device to adjust the tilt angle of the storage tank, so that the storage tank changes from the gravity condition in the initial state to another working condition within a transient time, achieving the purpose of variable gravity, and further measuring the transient force and moment values of the storage tank under the variable gravity working condition, which can better simulate the working conditions of the storage tank in actual complex situations.

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

[0051] 3. During the measurement process, the test device and method of the present invention can accurately measure the rotational angular velocity, displacement, force, and tilt angle before and after the change of the storage tank posture, so as to quantitatively analyze the transient mechanical characteristics under the variable gravity working condition.

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

[0053] The following further describes the specific embodiments of the present invention in conjunction with the drawings.

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

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

[0056] Figure 3 is a schematic structural diagram of the slewing device of the present invention;

[0057] Figure 4 is the transient force curve of the variable gravity transient working condition experiment with preset targets;

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

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

[0060] Example 1. Device for measuring the transient mechanical characteristics of the storage tank under variable gravity conditions, 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 linkages in the middle, and a moving platform at the top. The two ends of the telescopic linkages are respectively fixedly connected to the fixed platform and the moving platform. The six-axis swing device 40 can be obtained through commercial purchase or customization. For example, the six-degree-of-freedom electric motion system of the ZY-PE series of Hangzhou Guochen Zhengyu Technology Co., Ltd. is adopted. The fixed platform of the six-axis swing device 40 is fixed on the turbine turntable 32 through a flange. This connection method ensures that the six-axis swing device 40 can rotate with the slewing device, and can withstand the forces and motion inertia in all directions, maintaining the stability of the six-axis swing device 40 and the uniformity of the force distribution. Each of the six telescopic linkages of the six-axis swing device 40 is equipped with a stepper motor and has two working states: one is to control the stepper motor through a single-chip microcomputer to respectively and quantitatively adjust the telescopic length of the telescopic linkages, so that the moving platform tilts at a preset angle; the other is that the stepper motor does not work, and the telescopic linkages are in a free telescopic state. The centrifugal force of the rotary motion of the turbine turntable 32 drives the telescopic linkages to extend or contract randomly, so that the moving platform tilts at a random angle, thereby being used to study the mechanical characteristics of the variable gravity working conditions of the storage tank at different tilt angles.

[0066] The storage tank clamping device 50 includes a support base 53 at the bottom, a support bracket 52 in the middle, and an annular gripper 51 at the top. Both the upper and lower ends of the support bracket 52 are fixedly connected to the annular gripper 51 and the support base 53, as Figure 2 shown. The storage tank 8 is a cylindrical shape with a smaller bottom and a larger top. The annular gripper 51 is sleeved on the lower part of the storage tank 8. A flexible pad is provided on the inner circle of the annular gripper 51 to increase the friction force to fix the storage tank 8. Since the diameter of the lower part of the storage tank 8 is slightly smaller than that of the upper part, the lower part of the storage tank 8 is clamped and fixed in the annular gripper 51 by gravity. The support base 53 is fixed on the moving platform of the six-axis swing device 40 through bolts. The central axes of the turbine turntable 32, the six-axis swing device 40, the storage tank clamping device 50, and the storage tank 8 are on the same straight line as the axis of the central main shaft, so that the storage tank 8 can change its attitude along with the six-axis swing device 40. At the same time, the rotary table 13 is used to drive the storage tank 8 to rotate uniformly on the horizontal plane, and the linear screw slide module is used to drive the linear reciprocating movement of the storage tank 8.

[0067] An upper part of the storage tank 8 is provided with a filling port, and a bottom part thereof is provided with a liquid discharge port. The liquid circulation device includes 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 through a flexible hose 87 in sequence after passing through a first one-way valve 83 and the gas-liquid separator 82. The liquid discharge port is connected to the three-way valve 84 through a flexible hose 87 in sequence after passing through a second one-way valve 85, and then the three-way valve 84 is connected to the self-priming pump 86 and the liquid storage tank 9 through a flexible hose 87 in sequence. 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 cut-off 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 rotates reversely. The first one-way valve 83 is in a cut-off state, and the second one-way valve 85 is in a conducting state. 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 liquid 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-fast 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 can move freely without being restricted by the flexible hose 87 during rotation and movement.

[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 fixedly connected to the moving slider 25. When the moving slider 25 reciprocates on the linear guide 24, the displacement measured by the displacement sensor 61 is equivalent to the displacement of the storage 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 storage tank 8 when the rotating table 13 and the turbine turntable 32 rotate at a constant 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 tilt angle of the storage tank 8 deflected with the six-axis swing device 40. 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, stop and rotation 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 central position of the bottom of the storage tank 8 to measure the forces generated during the experiment and moment values as well as the weight of the storage tank 8 after filling with liquid. The multi - dimensional force sensor is signal - connected to the single - chip microcomputer for transmitting the measured data

[0073] The single - chip microcomputer is signal - connected to the upper computer 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 upper computer, and at the same time receive the instructions from the upper computer

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

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

[0076] 2. The electric displacement device controls the position of the moving slider 25, and measures the displacement of the storage tank 8 through the displacement sensor 61

[0077] 3. The slewing device drives the six - axis swing device 40 to perform a slewing motion, thereby changing the rod lengths of the telescopic connecting rods of the six - axis swing device 40 to achieve the random inclination of the storage tank 8

[0078] The stepping motors of the six - axis swing device 40 respectively quantitatively adjust the telescopic lengths of the telescopic connecting rods, so that the moving storage tank 8 inclines at a preset angle

[0079] 4. The adjustment ranges of the angles between the axis of the storage tank 8 after the attitude change and the X - axis and the Y - axis are both , and the adjustment range of the angle with the Z - axis is ; Since the rotational parameter situations of the axis and the axis are basically the same, to simplify the test workload, during the experiment when the storage tank 8 is vertically placed, only the rotational experiments of the axis and the

[0080] axis are carried out 5. When the gravitational acceleration at the initial attitude of the six - axis swing device 40 (the storage tank 8 is vertically placed along the axis) is , when the attitude of the storage tank 8 changes (i.e., variable gravity condition), the components of gravity on each axis will also change accordingly. At this time, it can be considered that the gravity components on each axis after the attitude change of the storage tank 8 are obtained after the initial components rotate around each axis. According to the gravity components at the initial attitude and the gravity components after the attitude change (i.e., variable gravity condition), the inclination angles of each axis of the storage tank 8 from the initial attitude to the variable gravity condition are solved, and 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 storage tank under variable gravity conditions of the present invention is specifically as follows:

[0082] 1. Construct an equivalent gravity model of the device for measuring transient mechanical characteristics of a storage tank under variable gravity conditions as:

[0083] (1)

[0084] Wherein, is the gravitational acceleration of the initial attitude of the storage tank 8, is the gravitational acceleration after the variable gravity condition, ω is the rotational angular velocity of the storage tank 8, is the angle between the central axis of the storage tank 8 and the X-axis, is the angle between the central axis of the storage tank 8 and the Z-axis, R is the displacement of the storage tank 8, and the value is taken within the range of ;

[0085] 2. Preset the research on the variable gravity transient condition of the target

[0086] 2.1 Set the target of the variable gravity transient condition:

[0087] (1) After the gravity changes transiently, the preset target force in the x-axis direction is , and the preset target force in the z-axis direction is :

[0088] (2)

[0089] (3)

[0090] Wherein, m is the mass of the storage tank 8 after filling with liquid, measured by a multi-dimensional force sensor; is the target value of the gravity component in the x-axis direction after the variable gravity transient condition, is the target value of the gravity component in the z-axis direction after the variable gravity transient condition.

[0091] (2) When the displacement of the storage tank 8 is preset as R, the target tilt angle after the variable gravity transient condition (including the angle between the central axis of the storage tank 8 and the X-axis, the angle between the central axis of the storage tank 8 and the Z-axis) is:

[0092] (4)

[0093] (5)

[0094] Wherein, is the target rotational angular velocity:

[0095] (6)

[0096] Wherein, is the target centripetal acceleration;

[0097] (3) The target of the variable gravity transient working condition is:

[0098] When the distance between the storage tank 8 and the center of the rotating table 13 is R and it rotates at a uniform speed with the target rotational angular velocity when the angle between the central axis of the storage tank 8 and the X-axis is the target value and the angle between the central axis of the storage tank 8 and the Z-axis is the target value the force on the storage tank 8 in the x-axis direction reaches the preset target and the force on the storage tank 8 in the z-axis direction reaches the preset target so as to achieve the purpose of variable gravity.

[0099] 2.2 Realization process of variable gravity transient working condition

[0100] 2.2.1 Initializing the device

[0101] Inject liquid into the storage tank 8 through the liquid circulation device so that the mass of the storage tank 8 reaches m after the injection; then disconnect the flexible hose 87 from the liquid discharge port and the filling port;

[0102] Turn on the switches of the multi-dimensional force sensor, displacement sensor 61, acceleration sensor 63 and three-axis angle calibrator 62, and reset and adjust the attitude of the six-axis swing device 40 so that the storage tank 8 is in the initial state, that is, the vertical state.

[0103] 2.2.2 Moving the storage tank 8 to the target position

[0104] Start the second servo motor 21, move the slider 25 to perform a translational motion along the linear guide 24. When the displacement of the storage tank 8 measured by the displacement sensor 61 is R, the storage tank 8 reaches the target position, and the second servo motor 21 locks the position of the slider 25.

[0105] 2.2.3 The storage tank 8 rotates at a uniform speed with the target rotational angular velocity at a uniform speed

[0106] Start the first servo motor 11, the rotating table 13 starts to rotate. When the centripetal acceleration measured by the acceleration sensor 62 is the rotating table 13 enters the uniform rotation state, and the storage tank 8 obtains the target rotational angular velocity .

[0107] 2.2.4. Start the six-axis swing device 40. The stepping motor of the six-axis swing device 40 quantitatively adjusts the telescopic lengths of the respective telescopic linkages so that the moving platform changes its attitude, and the storage tank 8 tilts towards the target tilt angle (the value preset by formula (5), the value preset by formula (4)). The value preset by formula (4). tilts.

[0108] 2.2.5. Real-time monitor the tilt angle during the attitude change of the storage tank 8 through the three-axis inclinometer 63, and real-time monitor the forces on the storage tank 8 during the attitude change through the multi-dimensional force sensor, including the force in the x-axis direction and the force in the z-axis direction .

[0109] 2.2.6. When the angle between the central axis of the storage tank 8 and the X-axis is equal to the value preset by formula (5), and the angle between the central axis of the storage tank 8 and the Z-axis is equal to the value preset by formula (4), the attitude of the storage tank 8 is adjusted to the target position, achieving the gravity target after the variable gravity transient condition and . At this time (when the attitude of the storage tank 8 is adjusted to the target position), the value should be equal to or close to the preset target , and similarly, the value should be equal to or close to the preset target . value should be equal to or close to the preset target .

[0110] 3. Research on random variable gravity transient conditions

[0111] 3.1. Objectives of random variable gravity transient conditions: The slewing device rotates randomly, and the transient forces and torques are measured during the attitude change of the storage tank 8;

[0112] 3.2. Implementation process of random variable gravity transient conditions

[0113] 3.2.1. Initialize the device, same as step 2.2.1.

[0114] 3.2.2. Move the storage tank 8 to the target position, same as step 2.2.2.

[0115] 3.2.3. Start the first servo motor 11, and the rotating table 13 starts to rotate and enters a uniform rotation state.

[0116] 3.2.4. Turn off the six-axis swing device 40, and the respective telescopic linkages of the six-axis swing device 40 are in a free adjustment state;

[0117] Start the third servo motor 31, 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, and the telescopic linkages of the six-axis swing device 40 randomly extend and contract in length to change the attitude of the moving platform;

[0118] 3.2.5. Real-time monitor the tilt angle of the storage tank 8 during each attitude change process through the three-axis inclinometer 63, and real-time monitor the force on the storage tank 8 during each attitude change process through the multi-dimensional force sensor, including the force in the x-axis direction and the force in the z-axis direction , and measure the centripetal acceleration of the storage tank 8 through the acceleration sensor 62 to obtain the rotational angular velocity ω, which is used for the research of the random variable gravity transient working condition.

[0119] Experiment:

[0120] Verify the effectiveness of the present invention by simulating the device and method for measuring the transient mechanical characteristics of the variable gravity working condition of the storage tank proposed in Embodiment 1 in a laboratory environment.

[0121] The volume of the storage tank 8 used in the experimental device is , and the total weight after filling with liquid is . The initial state of the storage tank 8 is in a vertical state, and the gravity component of the initial attitude is .

[0122] (1). Variable gravity transient working condition experiment with preset targets

[0123] Five groups of variable gravity transient working condition targets are preset for the experiment, as shown in Table 1.

[0124] Table 1. Preset targets of variable gravity transient working conditions

[0125]

[0126] After the rotary table 13 rotates at a constant speed with the target rotational angular velocity , the multi-dimensional force sensor continuously outputs the force during the movement of the storage tank 8 in real time . The force results after the attitude change of the storage tank 8 measured based on the preset targets in Table 1 are shown in Table 2.

[0127] Table 2. Comparison of the force after the attitude change of the storage tank and the target force

[0128]

[0129] As can be seen from Table 1 and Table 2, the force output by the multi-dimensional force sensor and the preset target between, and the preset target The errors between them are all within ±2%. By determining the adjustable parameters of each group, including the rotational angular velocity of the rotary table 13 , the angle α between the axis and the X-axis and the angle γ between the axis and the Z-axis when the attitude of the storage tank 8 changes, the preset target and the preset target can be stably obtained, and the preset target of the gravity component after the attitude change and .

[0130] This device has significant advantages in measuring the force and moment characteristics of the storage tank 8 under variable gravity conditions. Through the combination of the electric displacement device, the rotary device, and the six-axis swing device 40, the device of the present invention can comprehensively measure the transient force and moment characteristics of the storage tank 8 under different gravity conditions and attitudes. This not only simulates the complex space environment but also can accurately adjust the tilt angle and acceleration of the storage tank 8, thereby obtaining more valuable data for practical applications.

[0131] In contrast, the traditional experimental device for the storage tank of a ground transport vehicle only focuses on the liquid level fluctuation and modal change on the horizontal plane and fails to consider the influence of the change of the gravity field. Therefore, it cannot accurately reflect the response characteristics of the storage tank under multi-dimensional attitudes and different gravity environments. In addition, due to the lack of flexible control of the direction and magnitude of gravity, it is difficult for a ground transport vehicle to simulate the transient force and moment changes that the storage tank may encounter in a complex motion environment, which limits the applicability of the experimental data in a wider range of engineering applications.

[0132] (2) Visual output of the variable gravity transient condition experiment of the preset target

[0133] When the preset target , the preset target , the preset value of the angle between the central axis of the storage tank 8 and the X-axis after the attitude change of the storage tank 8 , the preset value of the angle between the central axis of the storage tank 8 and the Z-axis , through the single-chip microcomputer to accurately control the tilt angle of the moving platform of the six-axis swing device 40, the transient force curve during the variable gravity transient condition is as shown in Figure 4 .

[0134] (3) Visual output of the random variable gravity transient condition experiment

[0135] The rotational speed of the turbine turntable 32 is 2 rad / s, and the uniform rotational speed of the rotary 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 condition is as shown in Figure 5 , and after the attitude change of the storage tank 8 , .

[0136] ByFigure 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.

[0137] 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 slide block (25), wherein the linear guide rail (24) is arranged along the radial direction of the rotary table (13) and is fixedly connected to the rotary table (13); a third servo motor (31) and a turbine turntable (32) are arranged on the movable slide block (25), and the third servo motor (31) and the turbine turntable (32) are both fixedly connected to the movable slide block (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) via 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.

Images