Zero gravity environment simulation device and method compensating for additional mass inertia forces

Abstract

The application discloses a zero-gravity environment simulation device and method capable of compensating additional inertia force, and belongs to the field of micro-low gravity simulation test. The device comprises a near-zero stiffness supporting assembly, a motion following assembly, an adjustable air floating platform assembly and an inertia force compensation assembly. The near-zero stiffness supporting assembly and the motion following assembly realize vertical zero-gravity simulation, the air floating platform realizes horizontal zero-gravity simulation, and the inertia force compensation assembly comprises an inertia force compensation controller and a load acceleration sensor. The inertia force compensation controller is connected with the load acceleration sensor. The load acceleration sensor is responsible for monitoring the acceleration of a load device in x, y and z directions in real time, and transmits the acceleration signal to the inertia force compensation controller. Through the control of the motion following assembly and the adjustable air floating platform assembly, high-fidelity platform inertia force compensation is realized. The device and the method have fast response speed and high precision, and can realize high-fidelity zero-gravity simulation test in a large stroke.

Description

Technical Field

[0001] This invention belongs to the field of micro-low gravity simulation experiments in aerospace engineering, and more specifically, relates to a zero-gravity environment simulation device and method that can compensate for the inertial force of additional mass. Background Technology

[0002] The microgravity environment in outer space and on the surfaces of other celestial bodies can have unpredictable effects on the mechanical and control performance of spacecraft. Ground-based microgravity environment simulation technology is crucial to improving the safety and reliability of spacecraft performing missions in space.

[0003] Currently, there are two main configurations for microgravity simulation: one is the suspension simulation method based on a suspended pendulum mechanism, and the other is the support simulation method based on an air-bearing platform. Both methods can conduct long-term microgravity simulation experiments on large objects, and the cost per experiment is low and easy to implement. However, regardless of whether it is the suspension simulation method or the support simulation method, vertical gravity unloading is the key to achieving high-fidelity simulation with six degrees of freedom.

[0004] Literature indicates that the mainstream constant force support / suspension mechanisms currently include the counterweight method, the constant force cylinder method, and the rigid drive + elastic buffer element force feedback method. These methods can compensate for the gravity acting on spacecraft to varying degrees. However, the counterweight method leads to a significant increase in added mass, and the constant force cylinder method, due to the strong compressibility of gas, can cause nonlinear control and time delay problems. Currently, the rigid drive + elastic buffer element force feedback method is mainly used in China, but it is primarily limited by the accuracy of force sensors and cannot achieve Newton-level constant force control under ton-level loads.

[0005] Regardless of the mechanism used to unload gravity and release degrees of freedom, a portion of the support unit's structure is inevitably "bound" to the spacecraft. This added mass affects the accuracy of the spacecraft's microgravity simulation. In support methods based on air-bearing platforms, the added mass in translational degrees of freedom can sometimes exceed 50%, resulting in significant distortion in microgravity simulations.

[0006] Therefore, there is a need for a microgravity simulation device based on position control, with high precision and high response speed, and a method to compensate for its additional mass inertial force. Summary of the Invention

[0007] To address the shortcomings of existing technologies, the present invention aims to provide a zero-gravity environment simulation device and method that can compensate for the inertial force of additional mass. Through overall design, it is equipped with a near-zero stiffness support component, a motion following component, an adjustable air-float platform component, and an inertial force compensation component. It can compensate for the inertial force of additional mass, achieve position controllability, and has high precision and high response speed.

[0008] According to one aspect of the present invention, a zero-gravity environment simulation device capable of compensating for inertial forces in the X, Y, and Z translational directions is provided. The device includes a near-zero stiffness support assembly, a motion-following assembly, an adjustable air-float platform assembly, and an inertial force compensation assembly. The near-zero stiffness support assembly and the motion-following assembly are connected vertically to form a series structure. This series structure is floatingly mounted on the adjustable air-float platform assembly via air-float support. The inertial force compensation assembly is simultaneously mounted on both the near-zero stiffness support assembly and the motion-following assembly. During operation, external load equipment is fixed or hinged to the near-zero stiffness support assembly. The adjustable air-float platform assembly is used to adjust the device's tilt angle to compensate for the additional mass inertial forces in the two horizontal degrees of freedom. The inertial force compensation assembly is used to monitor the device's motion state and control the motion-following assembly and the adjustable air-float platform assembly to compensate for the additional mass inertial forces in all three degrees of freedom.

[0009] Furthermore, the near-zero stiffness support assembly includes a top plate, a bottom plate, a near-zero stiffness elastic element, an air-bearing guide rail, and a displacement sensor. The top plate and bottom plate are parallel to each other. The top plate is connected to an external load device to support the load device. The near-zero stiffness elastic element is disposed between the top and bottom plates and is composed of positive and negative stiffness elements connected in parallel, enabling high load-bearing capacity while achieving frictionless near-zero stiffness. The air-bearing guide rail is located at the center of the near-zero stiffness support assembly, between the top and bottom plates, to enable frictionless movement between the top and bottom plates and to restrict all degrees of freedom except the vertical degree of freedom. The displacement sensor is arranged between the top and bottom plates to monitor the height change of the near-zero stiffness elastic element.

[0010] Furthermore, the positive stiffness element is a metal helical spring; the negative stiffness element is a frictionless magnetic negative stiffness element; and the displacement sensor is a grating ruler displacement sensor, a laser displacement sensor, and / or an eddy current sensor.

[0011] Furthermore, one end of the positive stiffness element is connected to the top plate, and the other end is connected to one end of a height adjustment mechanism. The other end of the height adjustment mechanism is connected to the bottom plate. The height adjustment mechanism is used to adjust the initial preload of the near-zero stiffness support assembly, changing the support force provided by the near-zero stiffness elastic element, so as to adjust the buoyancy height of the top plate, thereby adjusting the working point of the negative stiffness element. The height adjustment mechanism is a nut and screw mechanism or a hydraulic mechanism.

[0012] Furthermore, the motion-following component includes a constant force controller and a linear motion mechanism. The linear motion mechanism is fixedly connected to the base plate. The constant force controller, by receiving feedback signals from the displacement sensor, drives and controls the linear motion mechanism to ensure a constant relative displacement between the top plate and the base plate, making the deformation of the near-zero stiffness elastic element near zero, thereby ensuring that the support force fluctuation of the top plate on the load equipment is near zero. The linear motion mechanism is a ball screw linear motion mechanism.

[0013] Furthermore, the adjustable air-bearing platform assembly is entirely mounted on an external foundation. This assembly includes an air-bearing bearing, an air-bearing platform, an attitude angle measurement unit, a cross-shaped flexible hinge, a linear flexible block, a piezoelectric actuator, and an attitude angle controller. The air-bearing bearing is mounted on the air-bearing platform and connects the adjustable air-bearing platform assembly and the motion-following assembly. The cross-shaped flexible hinge is connected to both the bottom of the air-bearing platform and the foundation, located between them and near the center of the air-bearing platform. This hinge restricts the air-bearing platform's degrees of freedom, except for rotation around the x and y axes. Similarly, the linear flexible block is positioned between the bottom of the air-bearing platform and the foundation, near the edge of the air-bearing platform. The linear flexible block has low longitudinal extension stiffness and low stiffness in rotation around the x and y axes; combined with the cross-shaped flexible hinge, it releases the air-bearing platform's degrees of freedom in rotation around the x and y axes. The piezoelectric actuator is also positioned between the air-floating platform and the foundation, parallel to the cross-shaped flexible hinge and the linear flexible block, and located between the cross-shaped flexible hinge and the linear flexible block. The attitude angle measurement unit is located at the edge of the air-floating platform. The attitude angle measurement unit is used to monitor the attitude angle signal of the air-floating platform in real time. The attitude angle controller is used to receive the attitude angle signal of the air-floating platform monitored and acquired in real time by the attitude angle measurement unit, and is also used to control the piezoelectric actuator to adjust the attitude angle of the air-floating platform in real time according to the attitude angle signal of the air-floating platform.

[0014] Furthermore, the combination of the cross-shaped flexible hinge, linear flexible block, piezoelectric actuator, and air-floating platform can be replaced by any air-floating platform capable of achieving high-precision tilt angle adjustment.

[0015] Furthermore, the attitude angle measurement unit is a laser tracker and / or a high-precision gyroscope.

[0016] Furthermore, the inertial force compensation component includes an inertial force compensation controller and a load acceleration sensor. The load acceleration sensor is installed on an external load device and is connected to the inertial force compensation controller. The load acceleration sensor is used to monitor the acceleration signal of the load device in real time and transmit the signal to the inertial force compensation controller. The inertial force compensation controller is also connected to the motion following component and the adjustable air flotation platform component.

[0017] Furthermore, the load acceleration sensor is a triaxial acceleration sensor, having at least one, mounted on the top plate of the load device or the near-zero stiffness support assembly, for monitoring changes in the acceleration of the load device, thereby enabling the calculation of the inertial force of the additional mass that needs to be compensated.

[0018] Furthermore, the load acceleration sensor should use a flexible cable to avoid disturbing the zero-gravity or micro-low-gravity environment simulation of the load device.

[0019] Furthermore, the load acceleration sensor monitors the acceleration of the load device in three directions in real time and transmits the monitoring signals to the inertial force compensation controller. The inertial force compensation controller generates an inertial force compensation displacement signal based on the vertical acceleration signal. The constant force controller is connected to the inertial force compensation controller so that it can adjust the relative displacement between the top plate and the bottom plate according to the inertial force compensation displacement signal, thereby changing the supporting force of the top plate on the load device and thus compensating for the inertial force of the additional mass in the vertical direction. The inertial force compensation controller is also used to generate an inertial force compensation angle signal based on the horizontal acceleration signal. The attitude angle controller is connected to the inertial force compensation controller so that the attitude angle controller can adjust the tilt angle of the air-floating platform according to the inertial force compensation angle signal. In addition, the horizontal component of the gravity of the load device is used to compensate for the inertial force of the additional mass in the horizontal direction.

[0020] According to a second aspect of the present invention, the inertial force compensation method for zero-gravity environment simulation using the above-described device specifically includes the following steps:

[0021] S1: Fix or hinge the load device to be simulated to the top plate in the gravity environment of the ground surface;

[0022] S2: Start the attitude angle controller and adjust the air-floating platform to a horizontal state through the piezoelectric actuator;

[0023] S3: Air is supplied to the air-bearing guide rail and air-bearing bearing to release the degree of freedom of vertical movement of the near-zero stiffness support component, and at the same time release the degree of freedom of horizontal movement of all components on the air-bearing platform. All components on the air-bearing platform float on the air-bearing platform.

[0024] S4: Change the supporting force of the positive stiffness element through the height adjustment mechanism until the top plate is lifted. The supporting force is provided by the near-zero stiffness elastic element. Continue to adjust the height adjustment mechanism to make the top plate rise slowly until the negative stiffness element works near the design zero point.

[0025] S5: Start the linear motion mechanism. Based on the height change signal of the near-zero stiffness elastic element monitored by the displacement sensor, the constant force controller drives the linear motion mechanism to control the movement of the base plate, so that the height change of the near-zero stiffness elastic element converges, so that the supporting force on the load equipment is constant, and acceleration is obtained in a zero gravity environment.

[0026] S6: Start the inertial force compensation controller. Based on the acceleration change information of the load equipment monitored by the load acceleration sensor, the inertial force compensation controller sends displacement signal and angle signal respectively. The constant force controller controls the movement of the base plate according to the displacement signal. By changing the height of the near-zero stiffness elastic element, the magnitude of the support force is changed to compensate for the vertical inertial force. The adjustable air-floating platform adjusts the tilt angle of the air-floating platform according to the angle signal. The horizontal component of gravity is used to compensate for the horizontal inertial force, thereby realizing a high-fidelity zero-gravity simulation test.

[0027] Furthermore, the method for obtaining the height change of the near-zero stiffness elastic element in S6 is as follows: measure the height value of the near-zero stiffness elastic element and the force change curve, and obtain the height change of the near-zero stiffness elastic element through the force signal of the change curve.

[0028] In summary, compared with the prior art, the above-described technical solutions conceived by this invention have the following advantages:

[0029] Beneficial effects:

[0030] By utilizing a load acceleration sensor to monitor the acceleration of the load equipment in real time, and compensating for the additional inertial force caused by the load mass through a motion-following component and an adjustable air-float platform component, the accuracy of micro-low gravity simulation experiments is greatly improved. Specifically, the inertial force compensation component is simultaneously installed on the near-zero stiffness support component and the motion-following component. During operation, the adjustable air-float platform component is used to adjust the tilt angle of the device to compensate for the additional mass inertial force in the two horizontal degrees of freedom. The inertial force compensation component is used to monitor the motion state of the device and control the motion-following component and the adjustable air-float platform component to compensate for the additional mass inertial force in all three degrees of freedom, thereby achieving a high-fidelity zero-gravity simulation experiment. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the structure of a three-degree-of-freedom zero-gravity environment simulation device capable of compensating for additional mass inertial forces according to an embodiment of the present invention.

[0032] Figure 2 yes Figure 1 Schematic diagram of the internal structure of the adjustable air flotation platform component;

[0033] Figure 3 This is a configuration diagram of the cross-shaped flexible hinge in an embodiment of the present invention;

[0034] Figure 4 This is a system block diagram of the additional mass inertial force compensation method of the device described in the embodiments of the present invention;

[0035] Figure 5 This is a schematic flowchart of the method for compensating for the additional mass inertial force of the device described in the embodiment of the present invention.

[0036] In the above figure reference numerals, the same reference numerals denote the same structure or component throughout, specifically:

[0037] 1-Negative stiffness element, 2-Top plate, 3-Positive stiffness element, 4-Air-bearing guide rail, 5-Height adjustment mechanism, 6-Load equipment, 7-Load acceleration sensor, 8-Displacement sensor, 9-Base plate, 10-Inertia force compensation controller, 11-Constant force controller, 12-High-pressure gas cylinder, 13-Air-bearing bearing, 14-Air-bearing platform, 15-Attitude angle controller, 16-Linear flexible block, 17-Piezoelectric actuator, 18-Attitude angle measurement unit, 19-Cross flexible hinge, 20-Linear motion mechanism, 21-Guide rail slider. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0039] Figure 1 This is a schematic diagram of a three-degree-of-freedom zero-gravity environment simulation device capable of compensating for additional mass inertial forces according to an embodiment of the present invention. It is a zero-gravity environment simulation device capable of compensating for inertial forces in the X, Y, and Z translational directions, including a near-zero stiffness support assembly, a motion-following assembly, an adjustable air-float platform assembly, and an inertial force compensation assembly. The near-zero stiffness support assembly and the motion-following assembly are connected vertically to form a series structure. This series structure is floating on the adjustable air-float platform assembly via air-float support. The inertial force compensation assembly is simultaneously mounted on both the near-zero stiffness support assembly and the motion-following assembly.

[0040] The near-zero stiffness support assembly includes a top plate 2, a positive stiffness element 3, a negative stiffness element 1, a height adjustment mechanism 5, a displacement sensor 8, an air-bearing guide rail 4, and a base plate 9. Specifically, the negative stiffness element 1 and the positive stiffness element 3 are connected in parallel to form a near-zero stiffness elastic element, which supports the mass of the simulated load equipment. The load-bearing capacity of the positive stiffness element 3 should be greater than the gravity of the simulated load equipment, and the absolute value of the stiffness of the negative stiffness element 1 should be slightly less than the stiffness of the positive stiffness element 3, so that the stiffness of the near-zero stiffness elastic element is positive and its stiffness is as small as possible. In this embodiment, the positive stiffness element is a metal helical spring, and the negative stiffness element is a frictionless magnetic negative stiffness component. The height adjustment mechanism 5 can adjust the installation height of the spring according to the mass of the load, thereby adapting to the simulation of different weights and gravity environments. The displacement sensor 8 is used to monitor the relative displacement of the near-zero stiffness elastic element, and the air-bearing guide rail 4 is used for frictionless guidance in the direction of gravity, ensuring that the relative displacement signal monitored by the displacement sensor 8 can be accurately converted into the supporting force on the load device 6 to be simulated. In this embodiment, the height adjustment mechanism 5 is a nut and screw mechanism, which can also be a hydraulic mechanism.

[0041] The motion-following assembly includes a constant force controller 11 and a linear motion mechanism 20. The linear motion mechanism 20 is fixedly connected to the base plate 9. Guide rail sliders 21 are arranged around the linear motion mechanism 20, serving to guide and resist some bending moments during operation. The constant force controller 11 receives feedback signals from the displacement sensor 8 and drives the linear motion mechanism 20 to ensure a constant relative displacement between the top plate 2 and the base plate 9. This results in near-zero deformation of the near-zero stiffness elastic element, thereby ensuring near-zero fluctuation in the supporting force of the top plate on the load equipment, achieving vertical micro-gravity simulation. The linear motion mechanism 20 can be a ball screw module or a linear motion module, which can be selected from commercially available mature products.

[0042] The adjustable air-float platform assembly includes a high-pressure gas cylinder 12, an air-float bearing 13, an air-float platform 14, an attitude angle controller 15, a linear flexible block 16, a piezoelectric actuator 17, an attitude angle measurement unit 18, and a cross-shaped flexible hinge 19. The high-pressure gas cylinder 12 supplies air to the air-float guide rail 4 and the air-float bearing 13 via a two-stage pressurization valve. It is mounted on the frame of the motion-following assembly to avoid the influence of ground-based air supply pipes on the accuracy of zero-gravity simulation. The volume and number of high-pressure gas cylinders 12 are determined by the duration of the simulation test. The air-float bearing 13 is fixed to the bottom of the motion-following assembly. Throttled high-pressure air generates an air film on the air-float platform 14, supporting the entire motion-following assembly, the near-zero stiffness support assembly, and other components located on the adjustable air-float platform. This releases the two horizontal degrees of freedom, thereby enabling microgravity simulation tests in the two horizontal degrees of freedom directions.

[0043] Figure 2yes Figure 1 A schematic diagram of the internal structure of the adjustable air flotation platform component. Figure 3 This is a configuration diagram of the cross-shaped flexible hinge in an embodiment of the present invention. As can be seen from the two diagrams, the cross-shaped flexible hinge 19 is a Hooke's hinge, installed on the upper side of the foundation, and connected to the bottom surface of the air-floating platform and the foundation respectively. Its stiffness around the x-axis and y-axis is very low, thus restricting the degrees of freedom other than rotation around the x-axis and y-axis. The linear flexible blocks 16 are installed at the lower left and lower right corners of the foundation, respectively, and have very low longitudinal tensile stiffness and stiffness around the y-axis. Under the combined action of the cross-shaped flexible hinge 19 and the linear flexible blocks 16, the rotational degrees of freedom of the air-floating platform 14 around the x-axis and y-axis can be released.

[0044] The attitude angle controller 15 uses four attitude angle measurement units 18 arranged on the air-bearing platform 14 as control feedback. In this embodiment, the attitude angle measurement unit 18 is the tracking head of the laser tracker, which controls the movement of two piezoelectric actuators 17 to precisely adjust the attitude angle of the air-bearing platform. The center distance configuration of the two piezoelectric actuators needs to be set in advance according to the size of the added mass and the external forces acting on the spacecraft.

[0045] The inertial force compensation assembly includes a load acceleration sensor 7 and an inertial force compensation controller 10. The load acceleration sensor 7 is a triaxial acceleration sensor, mounted on the top plate 2 or the load 6, with a quantity of, for example, 2 or 4, used to monitor acceleration signals in three directions of the load equipment. The load acceleration sensor 7 should use a flexible cable to reduce the disturbance caused by the cable to the vertical microgravity simulation test of the load equipment.

[0046] Figure 4 This is a system block diagram of the additional mass inertial force compensation method of the device described in the embodiment of the present invention. As shown in the figure, the vertical upward direction is positive, the mass of the load device is M, the total mass of the top plate 2, the air float, and other structures fixedly connected to the load device in the zero gravity simulation device is M′, the total mass of the near-zero stiffness support assembly, the motion following assembly, and other structures on the air buoyancy platform other than the load device is M1, and the gravitational acceleration at the Earth's surface is g. Then:

[0047] When the device is in operation, the near-zero stiffness elastic element provides a supporting force F in the vertical direction. sup =F con +F ine , where F con = (M+M ′ g is a pre-set value that changes the pre-compression of the positive stiffness spring 3 through the height adjustment mechanism 5. When the load equipment moves, the mass M of the top plate 2, air float, and other structures fixedly connected to the load equipment... ′ This introduces additional inertial forces, therefore the near-zero stiffness elastic element needs to be further compressed by Δx to provide F. ineBy compensating for M′a, the supporting force F provided by the near-zero stiffness elastic element can be obtained. sup = (M+M′)g+M′a, where the acceleration of the load under the action of external force F is... This ensures that the dynamic behavior of the load equipment located on the Earth's surface, under the influence of Earth's gravity and the supporting force of the microgravity simulation device, is precisely consistent with that in a zero-gravity environment.

[0048] Before using the zero-gravity environment simulation device of the present invention that can compensate for additional mass inertia, it is necessary to accurately measure the variation curve of the near-zero stiffness elastic element with the relative height of the top plate and the bottom plate (hereinafter referred to as the support force curve). The support force curve can be determined based on F ine The compression amount Δx of a near-zero stiffness elastic element can be obtained quickly and accurately.

[0049] The inertial force compensation controller 10 monitors the vertical acceleration of the load in real time through the load acceleration sensor 7 to obtain the inertial force F that needs to be compensated. ine =M′a, which is converted into the height change Δx of the near-zero stiffness elastic element through the support force curve, and the signal is transmitted to the constant force controller 11 in real time.

[0050] The constant force controller 11 uses the displacement sensor 8 to monitor the relative displacement between the top plate 2 and the bottom plate 9 in real time, and drives the linear motion mechanism 20 to move the bottom plate 9, ensuring that the height change of the near-zero stiffness elastic element is Δx. This ensures that the supporting force of the near-zero stiffness elastic element accurately meets F. sup =F con +F ine This allows for precise compensation of the additional inertial force with mass M′, achieving a high-fidelity vertical zero-gravity environment.

[0051] The microgravity environment simulation in the horizontal direction is achieved through an adjustable air-bearing platform assembly. Air bearing 13 is mounted at the bottom of the motion-following assembly, and the generated high-pressure air film supports the motion-following assembly, the near-zero stiffness support assembly, and the load equipment together, effectively releasing the two degrees of freedom in the horizontal direction. During the simulation, the tilt angle of the air-bearing platform is controlled to provide a horizontal force to the device to compensate for the additional mass inertial force. The tilt angle requirement for generating the horizontal compensation force must meet the following conditions: This allows us to obtain the absolute tilt angle of the air flotation platform.

[0052] The inertial force compensation controller 10 monitors the horizontal (X, Y axis) acceleration of the load in real time through the load acceleration sensor 7 to obtain the absolute tilt angle θ of the air-floating platform, and transmits this signal to the attitude angle controller 15 in real time. The attitude angle controller 15 uses the attitude angle measurement unit 18 as control feedback and uses a two-degree-of-freedom attitude adjustment structure composed of two piezoelectric actuators to precisely adjust the attitude angle θ of the air-floating platform, thereby accurately compensating for the additional inertial force of mass M1 brought by the near-zero stiffness support component and motion follower component, thus ensuring high-fidelity micro-low gravity simulation in the two degrees of freedom in the horizontal direction.

[0053] In practical engineering applications, the method and process for simulating a zero-gravity environment using the aforementioned three-degree-of-freedom simulation device are as follows:

[0054] Step 1: Lock the motion follower component, fix the load device on top 2, start the attitude angle controller 15, control the two piezoelectric actuators to adjust the attitude angle of the air-floating platform, and adjust the air-floating platform to a horizontal state.

[0055] Step Two: Open the air valve to supply air to the air-bearing guide rail 4 and air-bearing bearing 13 from the high-pressure air cylinder 12. The air-bearing guide rail 4 ensures that the near-zero stiffness support assembly is unaffected by friction during vertical movement; the air-bearing bearing 13 levitates the entire device on the air-bearing platform 14. This ensures that the resultant force F experienced by the load equipment during horizontal movement is reduced. (t) ≈0, achieving zero gravity simulation in the two horizontal degrees of freedom.

[0056] Step 3: Adjust the height adjustment mechanism 14 in the near-zero stiffness support assembly to slowly raise the top plate 2, ensuring that the entire support force is provided by the near-zero stiffness elastic element, so that the support force of the near-zero stiffness elastic element is F. con = (M+M ′ g, so that the load equipment to be simulated reaches static equilibrium under the gravitational field; by continuing to adjust the height adjustment mechanism 14 in the near-zero stiffness support assembly, the top plate 2 continues to rise, ensuring that the negative stiffness element in the static equilibrium state works exactly near the midpoint of the stroke (design zero point), and the height of the top plate 2 relative to the bottom plate 9 in this state is x0.

[0057] Step 4: After the equipment stabilizes, the simulation test begins. The constant force controller 11 in the displacement following assembly sends a velocity signal to the linear motion mechanism 20 based on the height change signal Δx monitored by the displacement sensor 8, controlling the movement of the base plate 9 to cause the height change of the near-zero stiffness elastic element to converge, providing a supporting force F. sup = (M+M ′ This ensures that at any given moment during the simulation period, the resultant force of the gravity acting on the simulated load equipment (including rigid fixed structures such as top plate 2) and the supporting force of the simulation device satisfies F. (t)=0, meaning that the dynamic behavior of the load equipment on the Earth's surface under the support of the Earth's gravity and the microgravity environment simulation device is exactly the same as that in a zero-gravity environment.

[0058] Step 5: The load equipment begins to move. The inertial force compensation controller generates displacement and angle signals based on the acceleration signal monitored by the load acceleration sensor 7. The displacement signal is obtained from the support force curve, specifically by calculating the inertial force F of the added mass. ine = ′ a. Based on the support force curve, the corresponding displacement magnitude is obtained. The constant force controller 11 controls the movement of the base plate 2 according to this displacement signal, changing the height of the near-zero stiffness elastic element, so that F sup = (M+M ′ )g+M ′ This compensates for the additional inertial force in the vertical direction. The angular velocity signal is received by the attitude angle controller 15, and the tilt angle of the air-bearing platform is adjusted via the piezoelectric actuator 17. This compensates for the additional inertial force in the horizontal direction.

[0059] The combined effect of the above operations can more accurately simulate a zero-gravity environment.

[0060] Those skilled in the art will readily understand that the above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A zero-gravity environment simulation device which can compensate for the added mass inertial force, characterized by, It includes a near-zero stiffness support assembly, a motion following assembly, an adjustable air floating platform assembly and an inertial force compensation assembly, wherein the near-zero stiffness support assembly is connected with the motion following assembly in series to form a series structure, the series structure is floatingly arranged on the adjustable air floating platform assembly by an air floating support mode, and the inertial force compensation assembly is arranged on the near-zero stiffness support assembly and the motion following assembly, The adjustable air floating platform assembly is arranged on a foundation in an external environment as a whole, and comprises an air floating bearing, an air floating platform, an attitude angle measuring unit, a cross flexible hinge, a linear flexible block, a piezoelectric actuator and an attitude angle controller. The air floating bearing is arranged above the air floating platform and is used to connect the adjustable air floating platform assembly and the motion following assembly. The cross flexible hinge is connected with the bottom of the air floating platform and the foundation and is located between the air floating platform and the foundation and at the center of the air floating platform. The cross flexible hinge is used to limit the degrees of freedom of the air floating platform except the rotation around the x-axis and the y-axis. The linear flexible block is also arranged between the bottom of the air floating platform and the foundation and is located at the edge of the air floating platform. The piezoelectric actuator is also arranged between the air floating platform and the foundation and is parallel to the cross flexible hinge and the linear flexible block. The attitude angle measuring unit is arranged at the edge of the air floating platform and is used to monitor the attitude angle signal of the air floating platform in real time. The attitude angle controller is used to receive the attitude angle signal of the air floating platform monitored by the attitude angle measuring unit in real time and is also used to control the piezoelectric actuator to adjust the attitude angle of the air floating platform in real time according to the attitude angle signal of the air floating platform. In operation, the load device in the external environment is fixed or hinged on the near-zero stiffness support assembly. The adjustable air floating platform assembly is used to adjust the inclination angle and compensate the inertial force of the additional mass in two degrees of freedom in the horizontal direction. The inertial force compensation assembly is used to monitor the motion state and control the motion following assembly and the adjustable air floating platform assembly to compensate the inertial force of the additional mass in three degrees of freedom.

2. A zero-gravity environment simulation device capable of compensating for added mass inertia forces according to claim 1, characterized in that, The near-zero stiffness support assembly comprises a top plate, a bottom plate, a near-zero stiffness elastic element, an air floating guide rail and a displacement sensor. The top plate and the bottom plate are parallel to each other. The top plate is connected with the load device in the external environment to support the load device. The near-zero stiffness elastic element is arranged between the top plate and the bottom plate and is composed of a positive stiffness element and a negative stiffness element in parallel. The air floating guide rail is arranged at the center of the near-zero stiffness support assembly and is located between the top plate and the bottom plate and is used to realize the frictionless motion between the top plate and the bottom plate and limit other degrees of freedom except the vertical degree of freedom. The displacement sensor is arranged between the top plate and the bottom plate and is used to monitor the height change of the near-zero stiffness elastic element.

3. A zero gravity environment simulation device compensating for added mass inertia forces according to claim 2, characterized in that The positive stiffness element is a metal coil spring. The negative stiffness element is a frictionless magnetic negative stiffness element. The displacement sensor is a grating ruler displacement sensor, a laser displacement sensor or / and an eddy current sensor. It also includes a height adjusting mechanism, one end of the positive stiffness element is connected to the top plate, the other end is connected to one end of the height adjusting mechanism, the other end of the height adjusting mechanism is connected to the bottom plate, the height adjusting mechanism is used to adjust the initial pre-tightening force of the near-zero stiffness supporting assembly, change the supporting force provided by the near-zero stiffness elastic element, and adjust the floating height of the top plate, so as to adjust the working point of the negative stiffness element, the height adjusting mechanism is a nut screw mechanism or a hydraulic mechanism.

4. A zero gravity environment simulation device capable of compensating for added mass inertia forces according to claim 2 or 3, characterized in that, The motion following assembly includes a constant force controller and a linear motion mechanism, the linear motion mechanism is fixedly connected to the bottom plate, the constant force controller drives and controls the linear motion mechanism by receiving the feedback signal of the displacement sensor, ensures that the relative displacement between the top plate and the bottom plate is constant, makes the deformation of the near-zero stiffness elastic element near zero, and thus ensures that the supporting force of the top plate to the load device fluctuates near zero, and the linear motion mechanism is a ball screw linear motion mechanism.

5. A zero gravity environment simulation device compensating for added mass inertia forces according to claim 4, characterized in that The attitude angle measuring unit is a laser tracker or / and a high-precision gyroscope.

6. A zero gravity environment simulation device compensating for added mass inertia forces according to claim 5, characterized in that The inertial force compensation assembly includes an inertial force compensation controller and a load acceleration sensor, the load acceleration sensor is installed on the load device in the external environment, is connected to the inertial force compensation controller, is used to monitor the acceleration signal of the load device in real time, and transmits the signal to the inertial force compensation controller, and the inertial force compensation controller is connected to the motion following assembly and the adjustable air floating platform assembly.

7. A zero gravity environment simulation device compensating for added mass inertia forces according to claim 6, characterized in that The load acceleration sensor is a three-axis acceleration sensor, and the number is at least one, which is installed on the load device or the top plate of the near-zero stiffness supporting assembly, and is used to monitor the acceleration change of the load device, so as to calculate the inertial force of the additional mass which needs to be compensated, The load acceleration sensor adopts a light and soft cable to avoid disturbance to the zero gravity or micro-low gravity environment simulation of the load device, In operation, the load acceleration sensor monitors the acceleration in three directions of the load device in real time, and transmits the monitoring signal to the inertial force compensation controller, the inertial force compensation controller generates an inertial force compensation displacement signal according to the acceleration signal in the vertical direction, the constant force controller is connected to the inertial force compensation controller, so as to adjust the relative displacement between the top plate and the bottom plate according to the inertial force compensation displacement signal, thereby changing the supporting force of the top plate to the load device to compensate the inertial force of the additional mass in the vertical direction, The inertial force compensation controller is also used to generate an inertial force compensation angle signal according to the acceleration signal in the horizontal direction, and the attitude angle controller is connected to the inertial force compensation controller, so as to adjust the inclination angle of the air floating platform according to the inertial force compensation angle signal.

8. Inertial force compensation method for the simulation of a zero-gravity environment using a device according to any one of claims 1 to 7, characterized in that, Specifically, the following steps are included: S1: fixing or hinging the load device to be simulated on the top plate in the surface gravity environment; S2: starting the attitude angle controller, adjusting the air floating platform to the horizontal state through the piezoelectric actuator; S3: supplying air to the air floating guide rail and the air floating bearing, releasing the vertical motion degree of freedom of the near-zero stiffness supporting assembly, and releasing the horizontal motion degree of freedom of all components on the air floating platform, and floating all components on the air floating platform. S4: Change the supporting force of the positive stiffness element by the height adjusting mechanism, so that the top plate is lifted up, continue to adjust the height adjusting mechanism, further make the top plate slowly rise, until the negative stiffness element works near the design zero point; S5: Start the linear motion mechanism, according to the height change signal of the near-zero stiffness elastic element monitored by the displacement sensor, the constant force controller drives the linear motion mechanism to control the bottom plate movement, so that the height change of the near-zero stiffness elastic element converges, the supporting force of the load device is constant, and the acceleration under the zero gravity environment is obtained; S6: Start the inertia force compensation controller, according to the acceleration change information of the load device monitored by the load acceleration sensor, the inertia force compensation controller sends displacement signal and angle signal respectively, the constant force controller controls the bottom plate movement according to the displacement signal, changes the height of the near-zero stiffness elastic element to change the supporting force to compensate the vertical inertia force, and the adjustable air floating platform adjusts the inclination angle of the air floating platform according to the angle signal, so as to compensate the horizontal inertia force through the component force of the gravity in the horizontal direction, so as to realize the high-fidelity zero gravity simulation test.

9. The method of inertia force compensation according to claim 8, wherein, In S6, the height change amount of the near-zero stiffness elastic element is obtained by measuring the height value and the force change curve of the near-zero stiffness elastic element, and the height change amount of the near-zero stiffness elastic element is obtained through the force signal of the change curve.

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