An experimental device containing a uniform distribution of gyro truss structures

Abstract

The application discloses an experimental device containing a uniform distribution gyro truss structure, which comprises a first connecting piece, a first rod, a rotor, a brushless motor, a motor connecting plate and a truss fixing plate. The first connecting piece and the second connecting piece are both assembled into the end face of the free end of the gyro truss structure through interference fit with the first rod, the second rod and the third rod. The four interface nodes of the first connecting piece and the second connecting piece are connected respectively. The third connecting piece and the fourth connecting piece are assembled into the gyro truss unit through interference fit with the first rod, the second rod and the third rod for multiple times. Each gyro truss unit is connected into the main body structure of the truss in the form of module. The brushless motor adds angular momentum to the truss structure. The vibration of the truss is suppressed through the uniform distribution gyro truss structure, which belongs to passive control. Compared with the PID control mode, the application has the advantages of quick reaction, low cost and fast effect.

Description

Technical Field

[0001] This invention specifically relates to an experimental device containing a uniformly distributed gyroscope truss structure, belonging to the field of vibration control. Background Technology

[0002] In practical engineering applications, spatial deployable truss structures have become increasingly widely used in recent years due to their advantages such as large folding ratio, light weight, and high stiffness. However, the vibration problem of these large, flexible, deployable truss structures has always been a challenge in dynamics. Distributing processors and actuators on flexible structures is one of the commonly used vibration reduction methods. Flywheels possess unique mechanical properties such as fixed-axis stability, precession, and gyroscopic dynamic effects. Furthermore, they do not consume fuel and can provide continuous control torque, thus they have been chosen as a commonly used actuator in structural vibration stabilization devices. However, adding a flywheel to a spatial structure makes the dynamics of the entire system more complex. PMMA is an abbreviation for acrylic or plexiglass, and it is the material used in the truss of this experiment and simulation.

[0003] Therefore, it is essential to clarify the dynamic characteristics of truss structures containing gyroscopes and to explore their modes. Summary of the Invention

[0004] The purpose of this invention is to propose an experimental device for measuring the eddy current phenomenon of a truss structure with a uniformly distributed rotor. This device can measure the natural frequency and displacement trajectory of the truss, enabling in-depth research into the eddy current phenomenon of the truss structure. Currently, spacecraft employ actuators such as jet thrusters, magnetic torquers, and flywheels, which utilize angular momentum exchange mechanisms. Jet thrusters are widely used in spacecraft orbit and attitude control, offering good control performance. However, a drawback is the limited fuel capacity available for the thrusters; excessive fuel consumption can affect the spacecraft's on-orbit lifespan. Furthermore, the jet plume generated by the thrusters can impact the precision instruments carried on board. Magnetic torquers generate torque through interaction with the Earth's magnetic field, allowing for attitude and orbit control without fuel consumption. However, the generated control torque is relatively small, making it difficult to meet the control requirements of most spacecraft in high orbits with weak Earth magnetic fields. Flywheels achieve vibration and attitude control of spacecraft through momentum exchange, offering high control stability, maneuverability, and fuel-free operation, significantly reducing launch costs and extending service life.

[0005] However, the addition of angular momentum exchange devices such as flywheels can affect the inherent characteristics of flexible structures such as trusses. Previous literature has mentioned that the addition of angular momentum will have the following effects on beam structures: previously equal eigenvalues ​​will bifurcate as the angular momentum increases, and the trends of the eigenvalue curves of different orders will also be different; previously decoupled mode shapes will couple with the addition of angular momentum, causing the beam structure to vortex, and different order mode shapes will have two motion forms: forward vortex and backward vortex. However, the above analysis is based on theoretical derivation and lacks experimental verification. The purpose of this invention is to fill this research gap, verify the correctness of the theory through experiments, and illustrate the vortex of flexible structures in a more concrete form.

[0006] The present invention adopts the following technical solution:

[0007] An experimental device containing a uniformly distributed gyroscope truss structure includes a first connector (1), a first rod (5), a rotor (8), a brushless motor (9), a motor connecting plate (10), and a truss fixing plate (11); the first connector (1) and the second connector (2) are assembled with the first rod (5), the second rod (6), and the third rod (7) through an interference fit to form the end faces of the free ends of the gyroscope truss structure; the first connector (1) and the second connector (2) The structure consists of four interface nodes: rod 1 (5) is a diagonal rod, rod 2 (6) is a horizontal rod, and rod 3 (7) is a vertical rod. The four interface nodes of connector 1 (1) and connector 2 (2) are connected respectively. Connector 3 (3) and connector 4 (4) are assembled with rod 1 (5), rod 2 (6), and rod 3 (7) through interference fits to form a gyro truss unit cell. Each gyro truss unit cell forms the main truss structure in modular form. The motor connecting plate (10) itself has four through holes and is fixedly connected to the truss unit cell. The brushless motor (9) is connected to the motor connecting plate (10) by bolts, and the rotor (8) and the brushless motor (9) are connected together by bolts. The truss fixing plate (11) is fixedly connected to the main truss structure through interference fits. The brushless motor (9) adds angular momentum to the truss structure.

[0008] According to the principle of gyro precession, when a uniformly distributed gyro truss structure rotates at high speed around its axis of symmetry with an angular velocity ω, if it simultaneously precesses with an angular velocity Ω, and the gyro torque is M... G =M0=J Z ω×Ω. Where J Z It is the rotational inertia of the gyroscope about its rotation axis z. The gyroscope torque will cause the mode of the uniformly distributed gyroscope truss structure to change, thus the mode of the uniformly distributed gyroscope truss structure exhibits vortex phenomenon.

[0009] Excitation was applied to one side of the bottommost gyro truss unit cell using a vibrator. Measurement points were the top connectors of the sixth and topmost gyro truss units. The uniformly distributed gyro truss structure was placed vertically on a plane to eliminate the influence of its own weight on the experimental results, and its bottom was fixed to the ground with bolts. A simple harmonic excitation was applied to the uniformly distributed gyro truss structure, and the collected acceleration signals were expanded using Fourier calculations. To verify the vortex phenomenon caused by the addition of angular momentum, a motion trajectory experiment was added to the fixed points of the straight truss. This experiment used a vibrator to excite the fixed points, applying a unidirectional excitation in a fixed direction.

[0010] With the increasing importance placed on deep space exploration and other engineering projects, the use of deployable trusses is also growing. However, these structures inevitably experience vibration during deployment and operation, the root cause of which is resonance at the same frequency. Adding a rotor to the deployable truss structure transforms it into a gyroscopic flexible body. When the rotor's rotational speed varies, the gyroscopic torque generated by the coupling between the structure and the rotor alters the structure's inherent properties, causing a change in its natural frequency and resulting in frequency bifurcation. This allows for the selection of an appropriate rotational speed to match the corresponding frequency, thereby reducing structural vibration. Furthermore, the gyroscopic torque generated by the coupling of structural vibration and rotor angular momentum itself acts as a resistance force, reducing the vibration amplitude of the truss structure to some extent. Suppressing truss vibration through a uniformly distributed gyroscopic truss structure is a form of passive control. Compared to control methods such as PID control, its advantages include rapid response, lower cost, and faster effect. Attached Figure Description

[0011] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative examples and descriptions of the invention are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0012] Figure 1 This is a schematic diagram of the overall experimental apparatus for the uniformly distributed gyroscope truss structure described in this invention;

[0013] Figure 2 This is a schematic diagram of a unit cell of the truss structure with a rotor according to the present invention;

[0014] Figure 3 This is a schematic diagram of the rotor system described in this invention;

[0015] Figure 4 These are schematic diagrams of the four types of connectors described in this invention;

[0016] Figure 5 This is a diagram of the signal analysis system architecture.

[0017] The diagram is labeled as follows: 1-Connector No. 1, 2-Connector No. 2, 3-Connector No. 3, 4-Connector No. 4, 5-Pole No. 1, 6-Pole No. 2, 7-Pole No. 3, 8-Rotor, 9-Brushless Motor, 10-Motor Connecting Plate, 11-Truss Fixing Plate. Detailed Implementation

[0018] The technical solution of the present invention will be further described below with reference to the accompanying drawings:

[0019] like Figures 1 to 4 As shown, the experimental device for a uniformly distributed gyroscope truss structure of the present invention mainly includes a first connector (1), a first rod (5), a rotor (8), a brushless motor (9), a motor connecting plate (10), and a truss fixing plate (11); the first connector (1) and the second connector (2) are assembled with the first rod (5), the second rod (6), and the third rod (7) through an interference fit to form the end face of the free end of the truss structure; the first connector (1) and the second connector (2) are four-interface nodes, the first rod (5) is a diagonal rod, the second rod (6) is a horizontal rod, and the third rod (7) is a vertical rod; the four-interface nodes of the first connector (1) and the second connector (2) are connected respectively, and the third connector (3) and the fourth connector (4) are assembled with the first rod (5), the second rod (6), and the third rod (7) through an interference fit to form the unit cell of the truss, and the entire truss main structure is composed of the same structure. The motor connecting plate (10) has four through holes and is fixedly connected to the truss unit cell. The brushless motor (9) is connected to the motor connecting plate (10) by bolts, and the rotor (8) and the brushless motor (9) are also connected by bolts. The truss fixing plate (11) is fixedly connected to the main truss structure by an interference fit. The overall structure is a cuboid with a length, width, and height of 100mm × 100mm × 1100mm. In subsequent experiments, the brushless motor is powered by a battery and an ESC to increase the angular momentum of the truss structure.

[0020] According to the principle of gyroscope precession, when a gyroscope rotates at high speed around its axis of symmetry with an angular velocity ω, if it simultaneously precesses with an angular velocity Ω, and the gyroscope torque M... G =M0=J Z ω×Ω. Where J Z This is the moment of inertia of the gyroscope about its rotation axis z. Ultimately, the gyroscopic torque will cause changes in the modes of the truss structure, resulting in vortex phenomena in the truss modes.

[0021] In this experiment, excitation was applied to one side of the bottommost unit cell of the truss using a vibrator. Measurement points were the top connectors of the sixth and top unit cells. The main truss structure was placed vertically on a plane to eliminate the influence of its own weight on the experimental results, and its base was secured to the ground with bolts. Simple harmonic excitation was applied to the truss, and the collected acceleration signals were expanded using Fourier transform calculations. To verify the vortex phenomenon in the truss structure due to the addition of angular momentum, a motion trajectory experiment was added to the fixed points of the straight truss. This experiment used a vibrator to excite the fixed points, applying a unidirectional excitation in a fixed direction.

[0022] Example

[0023] An experimental apparatus for measuring eddy current phenomena in a truss structure with a uniformly distributed rotor mainly includes an external rotor brushless motor, a PMMA motor connecting cross plate and protective shell, a steel rotor, and a PMMA truss.

[0024] The truss structure described in this patent is a linear deployable truss structure. The horizontal, vertical, and diagonal bars of this structure are all round bars made of PMMA. The connectors of the linear truss are made of PVC. The external rotor brushless motor is connected to the truss through a PMMA cross-shaped square plate, and an outer protective shell is added to prevent the rotor from falling off. The external rotor brushless motor is fixed to the truss through a motor connecting plate. The rotor is made of structural steel based on the maximum power of the external rotor brushless motor.

[0025] First, the linear truss structure described in this invention is constructed. Solid PMMA round bars with a diameter of 6mm are selected as the horizontal, vertical, and diagonal bars of the linear truss structure, with lengths of 70mm, 70mm, and 93mm, respectively. The connectors are 20mm long and high, 30mm wide, and 2mm thick. The four different connectors are connected to the bars by interference fit, and are then secondary fixed with resin adhesive after the assembly is completed.

[0026] The gyroscope rotor system of the present invention includes a brushless motor and a rotor. The rotor and the brushless motor are connected by bolts. The mass block and the brushless motor are combined into a rotor system after high-precision dynamic balancing. The motor connecting plate is bonded to the motor protective shell with resin glue and fixed to the crossbars and vertical bars of the truss through the holes on the motor connecting plate.

[0027] Furthermore, the rotor and the brushless motor described in this invention are connected using M2 screws through a through hole on the rotor and a threaded hole on the top of the brushless motor.

[0028] The gyroscope rotor system also includes a signal analysis system, which comprises: a signal receiver, a signal amplifier, an exciter, a truss main structure, a computer, sensors, and signal analysis software. First, the signal generator selects and sets a suitable signal. The signal amplifier amplifies the electrical signal to a level compatible with the exciter and the experimental environment. This signal is then connected to the deployable truss structure via a threaded hole at the top of the exciter, providing corresponding excitation to the truss main structure. The sensors are connected to the truss main structure using hot melt adhesive. Various signals, such as acceleration magnitude, force magnitude, and velocity magnitude, are collected. The signal receiver collects signals through the sensors and sends them to the computer. Using the computer's internal analysis software, signal processing methods such as Fourier transform are applied to process the collected signals into the required data, enabling analysis of the truss main structure in the experiment and subsequent structural optimization.

[0029] The main process of modal analysis is as follows: the exciter provides a predetermined excitation to the main truss structure, the response and time mileage of the main truss structure are measured through the data acquisition system, and the physical parameters of the system are determined after processing the obtained response data.

[0030] The above description is only one embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiment, but it can be considered that various ways of disclosing the principle herein are still within the scope of the claims.

Claims

1. An experimental device comprising a uniformly distributed gyro truss structure, characterized by: The application relates to a uniform distribution gyro truss structure, which comprises a first connecting piece (1), a first rod (5), a rotor (8), a brushless motor (9), a motor connecting plate (10), a truss fixed plate (11), and the first connecting piece (1) and the second connecting piece (2) are both connected with the first rod (5), the second rod (6) and the third rod (7) through interference fit to assemble the end face of the free end of a gyro truss structure, the first connecting piece (1) and the second connecting piece (2) are four-interface nodes, the first rod (5) is an inclined rod, the second rod (6) is a horizontal rod, and the third rod (7) is a vertical rod, the four-interface nodes of the first connecting piece (1) and the second connecting piece (2) are connected respectively, the third connecting piece (3) and the fourth connecting piece (4) are connected with the first rod (5), the second rod (6) and the third rod (7) through interference fit and are assembled into a gyro truss unit cell for multiple times, the gyro truss unit cells are connected in a modular form to form a truss main body structure, the motor connecting plate (10) is provided with four through holes and is fixedly connected with the truss unit cell, the brushless motor (9) is connected with the motor connecting plate (10) through bolts, the rotor (8) and the brushless motor (9) are connected through bolts, and the truss fixed plate (11) is fixedly connected with the truss main body structure through interference fit; and the brushless motor (9) increases angular momentum for the truss main body structure. According to the precession principle of gyro, when the truss main structure rotates around its symmetry axis with angular velocity ω, if it precesses with angular velocity Ω at the same time, the gyro torque is ; in the formula is the rotational inertia of the gyro around the rotation axis z, the gyro torque will change the mode of the truss main structure, thus the vortex phenomenon occurs in the uniform gyro truss structure mode; A vibration exciter is used to apply excitation to one side of the bottom gyro truss unit cell, and the measuring points are the sixth gyro truss unit cell top connecting piece and the top connecting piece of the top unit cell in the gyro truss; the uniform distribution gyro truss structure is vertically placed on a plane to eliminate the influence of the self weight of the uniform distribution gyro truss structure on the experimental results, and the bottom ground of the uniform distribution gyro truss structure is fixed by bolts; the uniform distribution gyro truss structure is subjected to simple harmonic excitation, and the collected acceleration signals are subjected to Fourier calculation and expansion; in order to verify the vortex phenomenon of the truss structure due to the addition of angular momentum, the motion trajectory experiment of the straight truss fixed point is increased, the motion trajectory experiment of the truss fixed point is carried out by the vibration exciter excitation method, and single-direction excitation is applied in the fixed direction.

2. The experimental device containing the uniform distribution of the gyro truss structure according to claim 1, characterized in that: The experimental device further comprises a signal analysis system, and the signal analysis system comprises a signal generator, a signal amplifier, a vibration exciter, a truss main body structure, a computer, a signal receiver, a sensor and signal analysis software; firstly, an electric signal is selected and set by the signal generator, the electric signal is amplified to an electric signal suitable for the vibration exciter and the experimental environment through the signal amplifier, and the vibration exciter is connected with the uniform distribution gyro truss structure through the threaded hole at the top of the vibration exciter; the sensor is connected with the uniform distribution gyro truss structure through hot melt adhesive, and the acceleration size, force size and speed size signals are collected; the signal receiver collects signals through the sensor and sends the signals to the computer end, the signal analysis software of the computer end is used, the signal analysis software is subjected to signal processing, the uniform distribution gyro truss structure in the experiment is analyzed, and subsequent structure optimization is carried out.

3. The experimental device containing the uniform distribution of the gyro truss structure according to claim 1, characterized in that: The analysis process of the uniform distribution gyro truss structure mode is that the vibration exciter gives a predetermined excitation to the uniform distribution gyro truss structure, the response and time mileage of the uniform distribution gyro truss structure are measured, and the physical parameters of the uniform distribution gyro truss structure are determined after the obtained response data are processed.

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