Vibration Measurement and Control Device and Method for Rigid-Flexible Coupled Structures with Multiple Flexible Bodies

Abstract

This invention discloses a vibration measurement and control device for a multi-flexible-body structure with rigid-flexible coupling, comprising a flexible hinge platform, a multi-flexible-body structure, a vibration detection section, a vibration excitation section, and a drive control section. The flexible platform is driven by a wire pull to generate vibrations in multiple directions. Four different flexible structure platforms are connected and coupled, forming a multi-flexible-body rigid-flexible coupling structure. The relative displacement between the flexible structure platforms is measured using flexoelectric displacement sensors and laser displacement sensors to obtain the vibration information of the flexible structure platforms. Vibration control of the flexible hinge platform is achieved using piezoelectric actuators. This device can be used to study the influence of rigid-flexible coupling motion in multi-flexible-body structures and corresponding vibration control methods. It is suitable for high-precision, short-distance measurements. The vibration control using a combination of support beams, bow-shaped beams, and piezoelectric actuators allows for more precise control of the vibration of the flexible platform in various directions.

Description

Technical Field

[0001] This invention relates to the field of vibration measurement of rigid-flexible coupled structures, and more specifically, to a non-contact measurement device and method for measuring and controlling the vibration of rigid-flexible coupled multi-body structures. Background Technology

[0002] Rigid-flexible coupled motion systems are widely used in aerospace, rotating machinery, vehicle engineering, and robotics. These systems involve flexible components exhibiting a wide range of rigid body motion while simultaneously undergoing elastic deformation due to external excitation. This raises the issue of the coupling between the rigid body motion and elastic deformation of structural components. As rigid-flexible coupled multibody systems become increasingly large and complex, and as their operating speed requirements increase, accurately controlling the system's operation under different constraints, forces, and control conditions has become a major challenge in engineering research and design.

[0003] In the aerospace field, most spacecraft are rigid-flexible coupled systems. Modern spacecraft are typically composed of flexible structures such as beams, plates, and trusses, and also incorporate complex structures like large-span solar panels and robotic arms. Their natural frequencies are low, and their low-frequency vibration modes are easily excited by disturbances. The various vibration effects exhibited during operation can severely impact the stability of the spacecraft. To expand the working range of the robotic arm, it is generally mounted on a mobile base that can move along guide rails. The mobile base has significant flexibility, and due to the inertial forces generated by its rigid body motion, the flexible components will experience substantial vibrations, which will have a significant impact on the end-effector tracking trajectory. Only through coupled analysis of elastic deformation and rigid body motion can high-precision control be achieved.

[0004] Non-contact measurement offers many advantages over traditional contact-based sensor measurements. It does not affect the dynamic performance of the object being measured, does not interfere with its normal operation due to added mass, is non-destructive, and has strong anti-interference capabilities. However, the accuracy of non-contact measurements is generally lower than that of contact measurements. Non-contact measurement is a simple and effective method for vibration measurement, commonly using laser vibrometers, laser sensors, binocular vision systems, and multi-view vision systems.

[0005] Flexural electrical sensors are designed based on the positive flexural effect, which generates polarization signals due to strain gradients. Compared to piezoelectric sensors, sensors based on the flexural effect have higher temperature stability and better low-frequency response performance, making them more widely used in sensor applications. The working mechanism of flexural electrical sensors involves applying uniform stress to the material through reasonable structural design, creating a strain gradient that generates polarization, i.e., producing an apparent piezoelectric effect. Sensors based on the flexural effect are now widely used in curvature monitoring, structural health monitoring, and crack detection. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings and deficiencies of the prior art and provide a multi-flexible body structure rigid-flexible coupling vibration measurement and control device. It uses a laser displacement sensor for non-contact measurement, which has high measurement accuracy. It adopts a combination of support beam, bow beam and piezoelectric actuator for vibration control, which can more accurately control the vibration of the flexible platform in all directions.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0008] A multi-flexible body structure rigid-flexible coupling vibration measurement and control device includes a multi-flexible body structure part, a vibration detection part, a vibration excitation part and a drive control part;

[0009] The multi-flexible structure includes a vibration isolation unit platform, a deployable flexible structure, a translational flexible structure, and a rotational flexible structure;

[0010] The vibration isolation unit platform includes a vibration isolation unit, which includes a main frame, a body-centered cubic support frame, and a vibration damping unit. The body-centered cubic support frame connects the main frame and the vibration damping unit.

[0011] The deployable flexible structure includes a drive platform, a first link, a deployable layer, a second link, and a drive spring. The two drive platforms are respectively installed on the flexible hinge platform and are coupled together by the drive spring. One end of the first link is hinged to the lower drive platform, and the other end of the first link is hinged to the midpoint of the second link. One end of the second link is hinged to the upper drive platform, and the other end of the second link is hinged to the deployable layer.

[0012] The translational flexible structure includes a first ball joint platform, a spring steel plate, a translational platform, and a ball hinge. The first ball joint platform is installed on the flexible hinge platform. One end of the spring steel plate is connected to the first ball joint platform through the ball hinge, and the other end of the spring steel plate is hinged to the translational platform.

[0013] The rotating flexible structure includes a spring steel sheet, a spherical hinge, a second spherical hinge platform, and a rotating platform. The second spherical hinge platform is installed on the flexible hinge platform. One end of the spring steel sheet is connected to the second spherical hinge platform through the spherical hinge, and the other end of the spring steel sheet is hinged to the rotating platform.

[0014] The vibration detection section includes a flexible hinge, a flexural displacement sensor, a laser displacement sensor, and a charge amplifier. The flexural displacement sensor is mounted on the flexible hinge, the laser displacement sensor is fixed to the flexible hinge platform by a bracket, and the charge amplifier is connected to the flexible hinge. The flexural displacement sensor and the laser displacement sensor work together to detect the vibration between the flexible platforms.

[0015] The vibration excitation part includes a wire sleeve, a thin wire, a winch, a servo motor, a motor base, and a servo motor driver. The wire sleeve is fixed to the flexible hinge platform. The fixed end of the thin wire passes through the wire sleeve and is fixed to the flexible hinge platform. The driving end of the thin wire is fixed to the winch. The winch is connected to the servo motor. The servo motor is fixed to the base platform through the motor base. The servo motor driver is connected to the servo motor.

[0016] The drive control section includes a mass block, a support beam, an arc beam, a piezoelectric actuator, a piezoelectric amplifier circuit, a terminal block, a motion control card, and a computer. The piezoelectric actuator is mounted on a flexible hinge platform. An arc beam and a mass block are mounted on opposite sides of the piezoelectric actuator, respectively. The fixed ends of the support beam are mounted on the mass block, and the free ends of the support beam are connected to the flexible hinges. The piezoelectric amplifier circuit is connected to the piezoelectric actuator, and the terminal block is connected to the piezoelectric amplifier circuit. The laser displacement sensor, charge amplifier, and motion control card are connected to the terminal block, and the computer is connected to the motion control card.

[0017] Flexural displacement sensors and laser displacement sensors collect vibration signals from the support beam, the arched beam, and the flexible hinge. These vibration signals are transmitted to a computer via a terminal block and a motion control card. The computer generates corresponding control signals based on the vibration signals of the flexible structure. These control signals are then output to a piezoelectric amplifier circuit and a servo motor driver via the motion control card and the terminal block. The servo motor and thin wire control the vibration of the flexible hinge platform, while the piezoelectric actuator controls the vibration of the support beam and the arched beam. The deformation of the flexible hinge suppresses the vibration between the flexible platforms.

[0018] Preferably, the vibration isolation unit platform includes 16 vibration isolation units, which form a 4×4×1 array. The main frame is a conventional cubic lattice, and the body-centered cubic support frame includes 8 cross-shaped cross-section support plates. The vibration reduction unit includes support frames distributed in the X-axis, Y-axis, and Z-axis directions. The support frames are symmetrical multi-segment curved beams. A stud is installed at the center of the vibration isolation unit, and the stud is used to connect the cross-shaped cross-section support plates and the support frames.

[0019] Preferably, the unfolding layer is made of a flexible material, which contracts inward or expands outward when subjected to force; the drive spring has a wire diameter of 3mm, an original length of 80mm, and a stiffness coefficient of 125N / m.

[0020] Preferably, the spring steel sheet of the translational flexible structure is 60mm long, 10mm wide, and 0.2mm thick, and the radius of the first ball joint platform and the translational platform is 125mm.

[0021] Preferably, the spring steel sheet of the rotating flexible structure is 60mm long, 10mm wide, and 0.2mm thick, the radius of the second ball joint platform is 125mm, and the radius of the rotating platform is 65mm.

[0022] Preferably, the flexible hinge is made of a bending beam with quasi-zero stiffness characteristics, and positive and negative electrodes are installed on the bending beam. A charge amplifier is used to amplify the output charge when the bending beam bends.

[0023] Preferably, the height of the flexible hinge is 61.6 mm, the thickness of the bending beam is 0.2 mm, and the bending beam is formed by a smooth spline curve.

[0024] Preferably, each layer of the flexible hinge platform is equipped with four laser displacement sensors, which are used to acquire displacement information of four points on the flexible hinge platform.

[0025] Preferably, the four thin wires are fixed in pairs to the second and fourth flexible hinge platforms through wire sleeves, and the four thin wires are orthogonally distributed with a wire diameter of 2mm.

[0026] A vibration testing method for a rigid-flexible coupled system with multiple flexible bodies, applied to the aforementioned rigid-flexible coupled vibration measurement and control device for multiple flexible bodies, includes the following steps:

[0027] S1: The servo motor controls the thin wire to make the flexible structure and flexible platform vibrate. Through the coupling effect of multiple flexible structures, the flexible structure and flexible platform produce vibrations in different directions and frequencies.

[0028] S2: Flexural electrical effect displacement sensor and laser displacement sensor collect vibration signals from support beam, bow beam and flexible hinge, and transmit them to computer through terminal block and motion control card;

[0029] S3: The computer generates corresponding control signals based on the vibration signals of the support beam, the bow beam, and the flexible hinge. The control signals are output to the piezoelectric amplifier circuit and the servo motor driver through the motion control card and terminal board. The servo motor and thin wire control the vibration of the flexible hinge platform, the piezoelectric actuator controls the vibration of the support beam and the bow beam, and the deformation of the flexible hinge suppresses the vibration between the flexible platforms.

[0030] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0031] 1. This invention uses a laser displacement sensor for non-contact measurement, avoiding some drawbacks of traditional contact measurement methods, such as additional effects, sensitivity to noise, and low measurement accuracy; the laser displacement sensor uses laser triangulation, which is suitable for high-precision, short-distance measurement.

[0032] 2. Typical environmental vibrations are multi-frequency and multi-directional. This invention uses a wire-driven method to achieve vibrations of different frequencies in multiple directions, which can verify the vibration characteristics of rigid-flexible coupling of multiple flexible body structures under multiple direction and frequency conditions.

[0033] 3. This invention employs flexible structural platforms with different structures, which allows for a more comprehensive study of the vibration characteristics of rigid-flexible coupling in multi-flexible structures.

[0034] 4. This invention employs a displacement measurement method based on flexible electricity, providing a new approach for high-resolution sensing and flexible electric actuation.

[0035] 5. The present invention adopts a vibration control scheme combining a support beam, an arc-shaped beam, and a piezoelectric actuator, which can more accurately control the vibration of the flexible platform in all directions. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of the overall structure of a multi-flexible body structure rigid-flexible coupling vibration measurement and control device.

[0037] Figure 2 This is a front view of a rigid-flexible coupling vibration monitoring and control device for a multi-flexible body structure.

[0038] Figure 3 This is a schematic diagram of the vibration isolation unit.

[0039] Figure 4 A schematic diagram of the flexible structure.

[0040] Figure 5 This is a schematic diagram of a translational flexible structure.

[0041] Figure 6 This is a schematic diagram of a rotating flexible structure.

[0042] Figure 7 This is a schematic diagram of a flexible hinge.

[0043] Figure 8 This is a structural diagram of a PZT actuation device consisting of a mass block, a support beam, an arc-shaped beam, and a piezoelectric actuator.

[0044] Figure 9 This is a schematic diagram of a servo motor.

[0045] Figure 10This is a control flowchart for a rigid-flexible coupling vibration monitoring and control device for multiple flexible body structures.

[0046] Explanation of icon numbers:

[0047] 1-Vibration isolation unit; 101-Main frame; 102-Vibration damping unit; 103-Cross-shaped cross-section support plate; 2-Drive platform; 3-First connecting rod; 4-Expanding layer; 5-Second connecting rod; 6-Drive spring; 7-First ball joint platform; 8-Spring steel sheet; 9-Translation platform; 10-Spherical hinge; 11-Second ball joint platform; 12-Rotation platform; 13-Flexible hinge; 14-Flexural displacement sensor; 15-Laser displacement sensor; 16-Mass block; 17-Support beam; 18-Arch-shaped beam; 19-Piezoelectric actuator; 20-Wire sleeve; 21-Fine wire; 22-Windlass; 23-Servo motor; 24-Motor base; 25-Piezoelectric amplifier circuit; 26-Charge amplifier; 27-Terminal board; 28-Servo motor driver; 29-Motion control card; 30-Computer. Detailed Implementation

[0048] The following description, in conjunction with the accompanying drawings and specific embodiments, further illustrates the present invention's multi-flexible body structure rigid-flexible coupling vibration measurement and control device and method.

[0049] Please see Figure 1 and Figure 2 This invention discloses a multi-flexible-body structure rigid-flexible coupling vibration measurement and control device. The device includes a flexible hinge platform, a multi-flexible-body structure, a vibration detection part, a wire-driven part, and a drive control part. The multi-flexible-body structure includes a vibration isolation unit platform, an unfolding flexible structure, a translational flexible structure, and a rotational flexible structure.

[0050] Please see Figure 2 and Figure 3 The vibration isolation unit platform includes vibration isolation units 1, which are arranged in a 4×4×1 array of 16 vibration isolation units 1. Each vibration isolation unit 1 includes a main frame 101, a damping unit 102, and a body-centered cubic support frame. The main frame 101 is a conventional cubic lattice, and the body-centered cubic support frame consists of eight cross-shaped cross-section support plates 103, which are used to connect the outer main frame 101 and the inner damping unit 102. The damping unit 102 consists of support frames along the X, Y, and Z directions, referred to as the X-axis, Y-axis, and Z-axis support frames, respectively. Each support frame is a symmetrical multi-segment curved beam, and a stud is installed at the center of the main body of the vibration isolation unit 1, which is used to connect the cross-shaped cross-section support plates 103 and the support frames.

[0051] In this embodiment, the main frame 101 has dimensions of 60mm × 60mm, the width of the support column cross section of the main frame 1 is 3mm × 3mm, the thickness of the cross-shaped cross section support plate 103 is 0.2mm, and the thickness of the support frame is 0.5mm. The vibration isolation unit 1 can generate vibration isolation effects in the X, Y, and Z directions, forming a 4×4×1 array vibration isolation platform.

[0052] Please see Figure 1 and Figure 4 The deployable flexible structure includes a drive platform 2, a first connecting rod 3, a deployable layer 4, a second connecting rod 5, and a drive spring 6. Two drive platforms 2 are respectively mounted to the first and second flexible hinge platforms using screws, and are connected and coupled by the drive spring 6. One end of the first connecting rod 3 is hinged to the lower drive platform 2, and the other end is hinged to the midpoint of the second connecting rod 5, ensuring that the center plane of the deployable layer 4 and the lower drive platform 2 are always on the same plane. One end of the second connecting rod 5 is hinged to the upper drive platform 2, and the other end is hinged to the deployable layer 4. The deployable layer 4 is made of flexible material and can contract inward or expand outward under stress.

[0053] In this embodiment, the dimensions of the drive platform 2 are 120mm × 120mm × 16mm. The drive spring 6 has a wire diameter of 3mm, an original length of 80mm, and a stiffness coefficient of 125N / m. The maximum deformation dimension of the unfolding layer 4 is 299mm × 299mm × 20mm. The flexible unfolding mechanism has a single degree of freedom. The upper and lower drive platforms 2 are connected and coupled through the drive spring 6, causing the drive platform 2 to vibrate in the vertical direction. By controlling the deformation of the flexible unfolding layer 4, the vibration of the drive platform 2 can be controlled.

[0054] Please see Figure 1 , Figure 2 and Figure 5 The translational flexible structure includes a first ball joint platform 7, a spring steel plate 8, a translational platform 9, and a ball hinge 10. The first ball joint platform 7 is installed on the second flexible hinge platform by screws. One end of the spring steel plate 8 is connected to the first ball joint platform 7 through the ball hinge 10, and the other end of the spring steel plate 8 is hinged to the translational platform 9 by screws, ensuring that the spring steel plate 8 can rotate around the axis.

[0055] In this embodiment, the spring steel sheet 8 of the translational flexible structure is 60mm long, 10mm wide, and 0.2mm thick. The radius of the first ball joint platform 7 and the translational platform 9 is 125mm. On the one hand, the bending at both ends of the spring steel sheet 8 can be equivalent to the rotation of the flexible joints of the two platforms. At the same time, the reduction in vertical length caused by bending can be equivalent to the contraction of the flexible joints. On the other hand, the torsion of the spring steel sheet 8 can be equivalent to the rotation of the flexible joints in the vertical axis direction, giving the platform translational characteristics.

[0056] Please see Figure 1 , Figure 2 and Figure 6 The rotating flexible structure includes a spring steel sheet 8, a spherical hinge 10, a second spherical hinge platform 11, and a rotating platform 12. The second spherical hinge platform 11 is installed on the third flexible hinge platform by screws. One end of the spring steel sheet 8 is connected to the second spherical hinge platform 11 through the spherical hinge 10, and the other end of the spring steel sheet 8 is hinged to the rotating platform 12 by screws, ensuring that the spring steel sheet 8 can rotate around the screw axis.

[0057] In this embodiment, the spring steel sheet 8 of the rotating flexible structure is 60mm long, 10mm wide, and 0.2mm thick. The radius of the second ball joint platform 11 is 125mm, and the radius of the rotating platform 12 is 65mm. The different positions of the fixed ends of the platforms give them rotational characteristics.

[0058] Please see Figure 1 , Figure 2 and Figure 7 The vibration detection section includes a flexible hinge 13, a flexural electrical displacement sensor 14, a laser displacement sensor 15, and a charge amplifier 26. The laser displacement sensor 15 is fixed to each flexible hinge platform via a bracket. The flexural electrical displacement sensor 14 is mounted on two planes of the flexible hinge 13. The flexural electrical displacement sensor 14 and the laser displacement sensor 15 together detect the relative displacement between the flexible platforms. The flexible hinge 13 is composed of a centrally symmetrical bending beam with quasi-zero stiffness characteristics. Positive and negative electrodes are mounted on the bending beam. The charge amplifier 26 is connected to a terminal plate 27 to amplify the output charge when the bending beam bends. The flexible hinge 13 can bend in two directions and achieve a certain degree of torsion.

[0059] The vibration detection section can adjust the detection area of ​​the flexible structure by adjusting the position between the support and the flexible hinge platform. It can also adapt to vibration detection within the sensor range by adjusting the relative positional relationship between the laser displacement sensor 15 and the support. Four laser displacement sensors 15 are evenly distributed on each flexible hinge platform to obtain the displacement information of four points on the flexible hinge platform.

[0060] The flexible hinge 13 has a height of 61.6 mm and a bending beam thickness of 0.2 mm. Each bending beam is composed of a smooth spline curve transition, and the two bending beams are centrally symmetrical.

[0061] The laser displacement sensor 15 can accurately measure the position and displacement of an object without contact. It employs laser triangulation, a method generally suitable for high-precision, short-distance measurements. The laser emitter projects a visible red laser beam onto the surface of a flexible structure through a lens. The laser beam scattered by the surface passes through a receiver lens and is captured by an internal CCD linear camera. Depending on the distance, the CCD linear camera can capture this light spot at different angles. Based on this angle and the known distance between the laser and the camera, a digital signal processor calculates the distance between the sensor and the object being measured.

[0062] Please see Figure 1 , Figure 2 and Figure 9 The vibration excitation section includes a cable sleeve 20, thin wires 21, a winch 22, a servo motor 23, a motor base 24, and a servo motor driver 26. Four thin wires 21 are fixed in pairs to the second and fourth flexible hinge platforms via the cable sleeves 20, and are orthogonally distributed. The fixed ends of the thin wires 21 pass through the cable sleeves 20 and are fixed to the flexible hinge platform by set screws. The driving ends of the thin wires 21 pass around guide wheels and are fixed to the winch 22 to ensure tension of the wires during operation. The winch 22 is directly connected to the motor shaft of the servo motor 23 to drive and control the length of each wire. The four servo motors 23 are evenly distributed and fixed to the base platform via the motor base 24. The vibration excitation section causes the flexible platform to vibrate, and vibrations of different directions and frequencies can be generated by controlling the rotational speed of the servo motors 23.

[0063] In this embodiment, the diameter of the thin wire 21 is 2mm.

[0064] The working principle of the vibration excitation part is as follows: the computer 30 outputs a control signal, which passes through the motion control card 29 and the terminal board 27 in sequence, and outputs a control signal to the servo motor driver 28 to drive the servo motor 23. The servo motor 23 controls the length of each wire, so that the thin wire 21 fixed platform vibrates in multiple directions. Through the mutual coupling of each flexible structure platform and the flexible hinge 13, each platform vibrates in multiple directions. The vibration frequency of the experimental system is controlled by controlling the difference in the speed of the motor.

[0065] The working principle of the flexural electrical effect displacement sensor 14 is as follows: when vibration occurs, the bending beam generates a large strain and strain gradient, and outputs flexible charge. During the oscillation process, the total charge collected on the four parallel electrodes is amplified by the charge amplifier 26. The magnitude of the output charge can directly reflect the magnitude of the deformation. By correlating the charge response and mechanical response of the measured structure, the output of the flexible electrode charge and the corresponding load and displacement are extracted.

[0066] Please see Figure 1 , Figure 2and Figure 8 The drive control section includes a mass block 16, support beams 17, an arched beam 18, a piezoelectric actuator 19, a piezoelectric amplifier circuit 25, a terminal block 27, a motion control card 29, and a computer 30. The arched beam 18 and mass block 16 are symmetrically mounted on both sides of the piezoelectric actuator 19. The fixed ends of the two support beams 17 are symmetrically mounted on the mass block 16, and the free ends of the two support beams 17 are respectively connected to two symmetrical flexible hinges 13. The piezoelectric amplifier circuit 25 is connected to the piezoelectric actuator 19, and the piezoelectric amplifier circuit 25 and motion control card 29 are respectively connected to the terminal block 27. The computer 30 is connected to the motion control card 29.

[0067] Flexural displacement sensor 14 and laser displacement sensor 15 collect vibration signals from the flexible structure and transmit them through terminal block 27. The signals are then converted into digital signals by the A / D conversion module of motion control card 29 and transmitted to computer 30. Computer 30 uses the vibration signals of the platform collected by laser displacement sensor 15 and the displacement data of the output flexible charge response to run a corresponding vibration control algorithm to generate corresponding vibration control signals. These signals are converted into analog signals by the D / A conversion module of motion control card 29 and output from terminal block 27 to piezoelectric amplifier circuit 25. The piezoelectric amplifier circuit 25 amplifies the analog signals and uses piezoelectric actuator 19 to control the vibration of each support beam 17. The deformation of the support beams 17 suppresses vibration between platforms.

[0068] In this embodiment, the flexible hinge 13 is 3D printed using photopolymerization. The material is VisiJet M3 Crystal, with a Poisson's ratio of 0.33, an elastic modulus of Ep = 1.47 GPa, and a density of ρ = 1.02 g / cm3.

[0069] The laser displacement sensor 15 is a Keyence product, model IL-030, with a reference distance of 30mm and a measurement distance of 20 to 45mm. The light source is a red semiconductor laser with a wavelength of 655nm. The measurement linearity is ±0.05%FS, the repeatability is 1μm, and the sampling period is 0.33 / 1 / 2 / 5ms (4 levels of variable). The support beam 17 is made of epoxy resin sheet with dimensions of 104mm × 10mm × 0.5mm, a Poisson's ratio of 0.33, an elastic modulus of Ep = 26.8Gpa, and a density of ρ =

[0070] 1980kg / m 3 The piezoelectric actuator 19 is a product of ChipTomorrow Technology Co., Ltd., model NAC2228, with geometric dimensions of 50mm×7.8mm×1.3mm, weight of 4g, stiffness of 0.0019N / μm, resonant frequency of 180Hz, maximum driving voltage of ±100V, displacement of ±1000μm, and output force of 1.90N.

[0071] The base platform is assembled from three aluminum profiles of 600mm, 520mm, and 150mm lengths using angle iron. The end face of the base platform is a 600mm×600mm×8mm aluminum alloy plate, connected to the aluminum profiles with screws. The drive platform 2, first connecting rod 3, first ball joint platform 7, second ball joint platform 11, motor mount 24, etc., are 3D printed using FDM with PLA as the material. The servo motor 23 is a DJI product, model M3508, with a maximum power of 220W, maximum torque of 5N·m, continuous torque of 2.8N·m, rated voltage of 24V, weight of 35g, and maximum continuous current of 20A.

[0072] The piezoelectric amplifier circuit 25 uses the APEX-PA241DW model, developed by South China University of Technology. Its amplification factor reaches 52 times, amplifying -5V to +5V to -260V to +260V. The charge amplifier 26 uses the YE5850 model from Jiangsu Lianeng Electronics Co., Ltd. The motion control card 29 is the GUC-800-TPV-M23-L2-F8G model from Googol Technology Co., Ltd., providing 8 controllable axes and analog input and output ranging from -10V to +10V. The selected computer 30 has a Pentium G620 2.6GHz CPU, 4GB of memory, and a PCI interface on its motherboard, allowing for the installation of the motion control card 29.

[0073] Please see Figure 10 The present invention also discloses a method for measuring and controlling the rigid-flexible coupling vibration of a multi-flexible structure, applied to the aforementioned device for measuring and controlling the rigid-flexible coupling vibration of a multi-flexible structure, comprising the following steps:

[0074] S1: Four servo motors 23 control the thin wires 21 to make the flexible structure and flexible platform vibrate. Through the coupling effect of multiple flexible structures, the flexible structure and flexible platform vibrate in different directions and frequencies.

[0075] S2: The flexural electrical effect displacement sensor 14 and the laser displacement sensor 15 collect vibration signals from the support beam 17, the bow beam 18 and the flexible hinge 13, and transmit them to the computer 30 through the terminal block 27 and the motion control card 29.

[0076] S3: Based on the vibration signals of the support beam 17, the bow beam 18, and the flexible hinge 13, the computer 30 runs the corresponding vibration control algorithm to generate corresponding control signals. These signals are then converted into analog signals by the D / A conversion module of the motion control card 29 and output to the piezoelectric amplifier circuit 25 via the terminal board 27. The piezoelectric amplifier circuit 25 amplifies the analog signals and controls the vibration of the bow beam 18 and the support beam 17 via the piezoelectric actuator 19. The vibration of the flexible platform is controlled by the action of the support beam 17 on the flexible hinge 13.

[0077] Finally, by changing the control parameters and conducting repeated experiments, multiple experimental results were obtained to determine the vibration characteristics and control effect of the rigid-flexible coupling of the multi-flexible body structure.

[0078] In summary, the present invention has the following advantages and beneficial effects:

[0079] 1. This invention uses a laser displacement sensor 15 for non-contact measurement, avoiding some drawbacks of traditional contact measurement methods, such as additional effects, sensitivity to noise, and low measurement accuracy; the laser displacement sensor uses laser triangulation measurement method, which is suitable for high-precision, short-distance measurement.

[0080] 2. Typical environmental vibrations are multi-frequency and multi-directional. This invention uses a wire-driven method to achieve vibrations of different frequencies in multiple directions, which can verify the vibration characteristics of rigid-flexible coupling of multiple flexible body structures under multiple direction and frequency conditions.

[0081] 3. This invention employs flexible structural platforms with different structures, which allows for a more comprehensive study of the vibration characteristics of rigid-flexible coupling in multi-flexible structures.

[0082] 4. This invention employs a displacement measurement method based on flexible electricity, providing a new approach for high-resolution sensing and flexible electric actuation.

[0083] 5. The present invention adopts a vibration control scheme combining support beam 17, bow-shaped beam 18 and piezoelectric actuator 19, which can more accurately control the vibration of the flexible platform in all directions.

[0084] The above description is a detailed description of the preferred embodiments of the present invention. However, the embodiments are not intended to limit the scope of the patent application of the present invention. All equivalent changes or modifications made under the technical spirit disclosed in the present invention should fall within the patent scope covered by the present invention.

Claims

1. A vibration monitoring and control device for a multi-flexible body structure with rigid-flexible coupling, characterized in that, It includes a flexible body structure, a vibration detection system, a vibration excitation system, and a drive control system. The multi-flexible structure includes a vibration isolation unit platform, a deployable flexible structure, a translational flexible structure, and a rotational flexible structure; The vibration isolation unit platform includes a vibration isolation unit, which includes a main frame, a body-centered cubic support frame, and a vibration damping unit. The body-centered cubic support frame connects the main frame and the vibration damping unit. The deployable flexible structure includes a drive platform, a first link, a deployable layer, a second link, and a drive spring. The two drive platforms are respectively installed on the first flexible hinge platform and the second flexible hinge platform. The two drive platforms are coupled and connected by the drive spring. One end of the first link is hinged to the lower drive platform, and the other end of the first link is hinged to the midpoint of the second link. One end of the second link is hinged to the upper drive platform, and the other end of the second link is hinged to the deployable layer. The translational flexible structure includes a first ball joint platform, a spring steel plate, a translational platform, and a ball hinge. The first ball joint platform is installed on the second flexible hinge platform. One end of the spring steel plate is connected to the first ball joint platform through the ball hinge, and the other end of the spring steel plate is hinged to the translational platform. The rotating flexible structure includes a spring steel sheet, a spherical hinge, a second spherical hinge platform, and a rotating platform. The second spherical hinge platform is installed on the third flexible hinge platform. One end of the spring steel sheet is connected to the second spherical hinge platform through the spherical hinge, and the other end of the spring steel sheet is hinged to the rotating platform. The vibration detection section includes a flexible hinge, a flexural electrical effect displacement sensor, a laser displacement sensor, and a charge amplifier. The flexural electrical effect displacement sensor is installed on the flexible hinge, the laser displacement sensor is fixed to each layer of the flexible hinge platform by a bracket, and the charge amplifier is connected to the flexible hinge. The flexural electrical effect displacement sensor and the laser displacement sensor work together to detect the vibration between the flexible platforms. The vibration excitation part includes a wire sleeve, a thin wire, a winch, a servo motor, a motor base, and a servo motor driver. The wire sleeve is fixed to the second layer flexible hinge platform and the fourth layer flexible hinge platform. The fixed end of the thin wire passes through the wire sleeve and is fixed to the second layer flexible hinge platform and the fourth layer flexible hinge platform. The driving end of the thin wire is fixed to the winch. The winch is connected to the servo motor. The servo motor is fixed to the base platform through the motor base. The servo motor driver is connected to the servo motor. The drive control section includes a mass block, a support beam, an arc beam, a piezoelectric actuator, a piezoelectric amplifier circuit, a terminal block, a motion control card, and a computer. The piezoelectric actuator is installed on each layer of the flexible hinge platform. The arc beam and the mass block are installed on opposite sides of the piezoelectric actuator, respectively. The fixed ends of the support beam are installed on the mass blocks, and the free ends of the support beam are connected to the flexible hinges. The piezoelectric amplifier circuit is connected to the piezoelectric actuator, and the terminal block is connected to the piezoelectric amplifier circuit. The laser displacement sensor, charge amplifier, and motion control card are connected to the terminal block, and the computer is connected to the motion control card. Flexural displacement sensors and laser displacement sensors collect vibration signals from the support beam, the arched beam, and the flexible hinge. These vibration signals are transmitted to a computer via a terminal block and a motion control card. The computer generates corresponding control signals based on the vibration signals of the flexible structure. These control signals are then output to a piezoelectric amplifier circuit and a servo motor driver via the motion control card and terminal block. The servo motor and thin wire control the vibration of the second and fourth flexible hinge platforms, while the piezoelectric actuator controls the vibration of the support beam and the arched beam. The deformation of the flexible hinge suppresses the vibration between the flexible platforms.

2. The multi-flexible body structure rigid-flexible coupling vibration measurement and control device according to claim 1, characterized in that, The vibration isolation unit platform includes 16 vibration isolation units, which form a 4×4×1 array. The main frame is a conventional cubic lattice, and the body-centered cubic support frame includes 8 cross-shaped cross-section support plates. The vibration reduction unit includes support frames distributed in the X-axis, Y-axis, and Z-axis directions. The support frames are symmetrical multi-segment curved beams. A stud is installed at the center of the vibration isolation unit, which is used to connect the cross-shaped cross-section support plates and the support frames.

3. The multi-flexible body structure rigid-flexible coupling vibration measurement and control device according to claim 1, characterized in that, The unfolding layer is made of flexible material, which contracts inward or expands outward when subjected to force; the drive spring has a wire diameter of 3mm, an original length of 80mm, and a stiffness coefficient of 125N / m.

4. The multi-flexible body structure rigid-flexible coupling vibration measurement and control device according to claim 1, characterized in that, The spring steel sheet of the translational flexible structure is 60mm long, 10mm wide, and 0.2mm thick. The radius of the first ball joint platform and the translational platform is 125mm.

5. The multi-flexible body structure rigid-flexible coupling vibration measurement and control device according to claim 1, characterized in that, The spring steel sheet of the rotating flexible structure is 60mm long, 10mm wide, and 0.2mm thick. The radius of the second ball joint platform is 125mm, and the radius of the rotating platform is 65mm.

6. The multi-flexible body structure rigid-flexible coupling vibration measurement and control device according to claim 1, characterized in that, The flexible hinge is made of a bending beam with quasi-zero stiffness characteristics. Positive and negative electrodes are installed on the bending beam, and a charge amplifier is used to amplify the output charge when the bending beam bends.

7. The multi-flexible body structure rigid-flexible coupling vibration measurement and control device according to claim 6, characterized in that, The flexible hinge has a height of 61.6 mm, and the bending beam has a thickness of 0.2 mm. The bending beam is formed by a smooth spline curve.

8. The multi-flexible body structure rigid-flexible coupling vibration measurement and control device according to claim 1, characterized in that, Each layer of the flexible hinge platform is equipped with four laser displacement sensors, which are used to acquire displacement information of four points on the flexible hinge platform.

9. The multi-flexible body structure rigid-flexible coupling vibration measurement and control device according to claim 1, characterized in that, Four thin wires are fixed in pairs to the second and fourth flexible hinge platforms through wire sleeves. The four thin wires are orthogonally distributed and the diameter of the wires is 2mm.

10. A vibration testing method for a multi-flexible body structure in a rigid-flexible coupling system, applied to the rigid-flexible coupling vibration measurement and control device for multi-flexible body structures as described in any one of claims 1 to 9, characterized in that, Includes the following steps: S1: The servo motor controls the thin wire to make the flexible structure and flexible platform vibrate. Through the coupling effect of multiple flexible structures, the flexible structure and flexible platform produce vibrations in different directions and frequencies. S2: Flexural electrical effect displacement sensor and laser displacement sensor collect vibration signals from support beam, bow beam and flexible hinge, and transmit them to computer through terminal block and motion control card; S3: The computer generates corresponding control signals based on the vibration signals of the support beam, the bow beam, and the flexible hinge. The control signals are output to the piezoelectric amplifier circuit and the servo motor driver through the motion control card and terminal board. The vibration of the second and fourth flexible hinge platforms is controlled by the servo motor and the thin wire. The vibration of the support beam and the bow beam is controlled by the piezoelectric actuator. The vibration between the flexible platforms is suppressed by the deformation of the flexible hinge.

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