Vibration measurement and control device and method for double-coupled "convex" platform motion flexible structure

Abstract

The application discloses a vibration measurement and control device and method of a double-coupling 'convex' platform motion flexible structure, which comprises a mobile platform body part, a transmission part, a vibration detection part and a control part, wherein the mobile platform body part comprises a U-shaped mobile platform and a double-coupling 'convex' structure. The device can be used to study the influence of the U-shaped mobile platform with the double-coupling 'convex' structure on vibration motion under the structure of a multi-flexible body coupling and vibration control, and has certain application prospects in the field of vibration measurement and shock absorption control of a space flexible multi-layer structure.

Description

Technical Field

[0001] This invention relates to the field of vibration control of multi-body coupled structures, and particularly to a vibration measurement and control device and method for a dual-coupled "convex" shaped platform motion flexible structure. Background Technology

[0002] In the aerospace field, large size and low stiffness are important development trends for various aerospace structures. More and more structures are employing a coupling of rigid and flexible structures. Such structures can increase payload weight and improve the efficiency of launch vehicles. However, this also brings a series of new problems. These structures have low modal damping; if no measures are taken to suppress their vibrations, once subjected to a certain excitation force, their large-amplitude vibrations can persist for a long time, affecting not only operational accuracy but also causing premature fatigue failure. With the rapid advancement of aerospace technology, research on the rapid suppression of coupled vibrations of various structures is of great significance.

[0003] The mechanically amplified piezoelectric actuator utilizes an elliptical amplification mechanism design to amplify the linear displacement of the piezoelectric ceramic and output it in the direction perpendicular to the displacement. The elliptical mechanical amplification mechanism provides an easy-to-integrate mechanical interface. Summary of the Invention

[0004] In order to overcome the above-mentioned shortcomings and deficiencies of the prior art, the purpose of this invention is to provide a vibration measurement and control device and method for a dual-coupled "convex" shaped platform motion flexible structure.

[0005] The objective of this invention is achieved through the following technical solution:

[0006] A vibration monitoring and control device for a dual-coupled convex platform motion flexible structure includes:

[0007] The mobile platform body includes a U-shaped mobile platform. The base plate of the U-shaped mobile platform is provided with a double-coupled "convex" structure. The double-coupled "convex" structure includes a coupling frame and an upper structure. The upper structure includes a rigid plate. A top flexible beam is vertically placed on the upper end face of the rigid plate. The lower end face of the rigid plate is set on the coupling frame through a support beam. The rigid plates are coupled together and to the U-shaped mobile platform through springs. The springs are on the same horizontal plane.

[0008] Transmission system: Drives the U-shaped moving platform to move horizontally, and during the movement, the vertical side plate of the coupling frame vibrates;

[0009] Vibration detection section: used to detect vibration signals of the top flexible beam;

[0010] Control section: Used to suppress the vibration of the flexible beam based on the detected vibration signal of the top flexible beam.

[0011] Furthermore, the coupling frame is square, with an opening on the top surface of the square, and the sides of the coupling frame are treated with a ball end mill to form multiple concave semi-circular grooves.

[0012] Furthermore, there are eight support beams, and each coupled "convex" structure includes four beams. The four support beams are symmetrically arranged with openings about the top surface and are placed vertically.

[0013] Furthermore, the control section includes a piezoelectric fiber sheet driver and an amplified piezoelectric actuator. The piezoelectric fiber sheet driver is mounted on the top flexible beam, and the amplified piezoelectric actuator is mounted at the opening of the coupling frame. After the computer receives the vibration signal, it generates a corresponding control signal, inputs it into the motion control card, outputs it through the terminal board, and after being amplified by the piezoelectric amplifier circuit, it is input to the piezoelectric fiber sheet and the piezoelectric actuator to suppress the vibration of the top flexible beam and the coupling frame.

[0014] Furthermore, the vibration detection section includes a piezoelectric fiber sensor and an accelerometer. The piezoelectric fiber sensor and the accelerometer are mounted on the top flexible beam to detect the vibration signal of the top flexible beam. After being amplified by a charge amplifier, the signal is transmitted to the motion control card through a terminal board and then input into the computer.

[0015] Furthermore, the transmission part includes a servo motor driver, a servo motor, a guide rail, and a slider. The U-shaped moving platform is mounted on the guide rail via two sliders. The servo motor driver is connected to the servo motor to drive the U-shaped moving platform to move.

[0016] Furthermore, the two coupling frames in the dual-coupling "convex" structure are symmetrically arranged within the U-shaped moving platform, with a distance of 196mm between the two coupling frames.

[0017] Furthermore, the spring is connected to the center line of the rigid plate.

[0018] Furthermore, the enlarged piezoelectric actuator specifically comprises three.

[0019] A method based on the aforementioned vibration monitoring and control device includes the following steps:

[0020] Step 1: The computer sends control signals to the servo motor driver to drive the servo motor, which in turn moves the "U"-shaped moving platform, further pulling the double-coupled "convex" structure, thereby causing the coupled frame and the top flexible beam to vibrate.

[0021] Step 2: Use a piezoelectric fiber sensor to detect the vibration of the flexible beam placed at the top of the coupling frame to obtain a measurement signal. Use an accelerometer unit to detect the vibration signal of the flexible beam at the top to obtain a vibration signal.

[0022] Step 3: The piezoelectric sensor signal and accelerometer signal acquired in Step 2 are processed by the charge amplifier and then transmitted to the motion control card through the terminal board. The analog signal is then converted into a digital signal by the A / D conversion module inside the motion control card and transmitted to the computer.

[0023] Step 4: The vibration detection signal obtained in step 3 is used to obtain the corresponding vibration feedback signal through the computer. The signal is then output by the D / A converter of the motion control card, transmitted through the terminal board, and amplified by the piezoelectric amplifier circuit before being output to the piezoelectric fiber driver and the amplified piezoelectric actuator, thereby suppressing the vibration of the top flexible beam and the frame.

[0024] Step 5: Adjust the algorithm parameters multiple times, conduct repeated experiments, and analyze the experimental results to obtain the vibration characteristics and control effect of the flexible beam.

[0025] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0026] (1) In the coupled frame structure of this invention, there is a horizontally moving U-shaped moving platform and a treated frame side plate, which are coupled to the rigid plate by springs. There are multiple spring couplings and rigid-flexible couplings, which provides a hard condition for studying systems with a large number of rigid-flexible couplings and spring couplings.

[0027] (2) The present invention uses a lead screw drive mechanism, which has advantages such as closed-loop control and self-compensation error compared with other transmission mechanisms;

[0028] (3) The present invention is a multi-sensor system, which includes both an accelerometer and a piezoelectric fiber sheet sensor, which is beneficial to improving the accuracy of flexible beam measurement. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0030] Figure 2 yes Figure 1 A partial schematic diagram of the U-shaped mobile platform;

[0031] Figure 3 yes Figure 1 A schematic diagram of the coupling frame after the side panels have been treated;

[0032] Figure 4 yes Figure 1 Schematic diagram of the internal support structure of the centrally coupled frame;

[0033] Figure 5 yes Figure 1 Schematic diagram of a large-scale piezoelectric actuator;

[0034] Figure 6 yes Figure 1 A schematic diagram of the transmission part;

[0035] Figure 7 yes Figure 1 The main view;

[0036] Figure 8 yes Figure 1 The left view;

[0037] Figure 9 yes Figure 1 Top view;

[0038] Figure 10 This is a flowchart illustrating the process of inventing a control method. Detailed Implementation

[0039] The present invention will be further described in detail below with reference to the embodiments, but the implementation of the present invention is not limited thereto.

[0040] like Figures 1 to 9 As shown, a vibration monitoring and control device for a dual-coupled convex platform motion flexible structure includes a mobile platform body, a transmission part, a vibration detection part, and a control part.

[0041] The main body of the mobile platform includes a U-shaped mobile platform 11 and a double-coupled "convex" structure. The U-shaped mobile platform includes two side plates and a bottom plate. The U-shaped mobile platform is formed by bending sheet metal. The double-coupled "convex" structure is set on the bottom plate and located inside the U-shaped mobile platform. The double-coupled "convex" structure includes two "convex" structures set at a distance from each other and set on the bottom plate by bolts.

[0042] Each "convex" shaped structure includes a coupling frame 10 and an upper structure. The coupling frame is internally supported by a special structure, and the vertical side plates of the coupling frame 10 are treated to vibrate during horizontal platform movement. To avoid hindering the sliding between the "U"-shaped moving platform and the guide rail, the base of the U-shaped moving platform with connecting bolts uses a countersunk hole structure. The frames are symmetrically arranged within the U-shaped moving platform, with a spacing of 196mm between them, and are located at the center line of the width of the U-shaped moving platform.

[0043] The coupling frame 10 is square, with a lower end face, an upper end face and two side faces. An opening is provided in the middle of the upper end face, and the side faces are specially treated so that they can vibrate when moving horizontally.

[0044] Furthermore, to increase the system's nonlinearity and facilitate rapid coupling of vibrations, a support structure 14 is used inside the coupling frame. This support structure is specifically constructed of bent steel plates, with both ends fixed to the side plates of the coupling frame via right-angle brackets 15. The dimensions of the unbent steel plate are 250mm × 80mm × 2mm, and the inner diameter of the bent steel plate is 8mm.

[0045] Furthermore, the sides of the coupling frame undergo special treatment, specifically: concave semi-circular grooves are created on the sides of the coupling frame using a ball end mill. The presence of these grooves causes a change in the stiffness of the coupling frame, thus allowing vibrations to be rapidly transmitted within the frame and between the coupling frames.

[0046] The upper structure includes a rigid plate 6, support beams 8, and a top flexible beam 2. There are eight support beams 8, with four beams on the upper surface of each coupling frame to support the rigid plate. These beams are symmetrically arranged about the opening on the upper surface, with a distance of 45mm between beams on the same side. Each of the eight support beams measures 170mm × 70mm × 2mm. The support beams are connected to the coupling frame using right-angle brackets and side plates, and secured with bolts and nuts.

[0047] The rigid plate 6 is vertically mounted with a top flexible beam 2, which measures 670mm × 200mm × 2mm. Two vertically placed flexible beams are each mounted on their respective rigid plates. The distance between the top flexible beam and the side plate of the U-shaped moving platform is 375mm. Right-angle brackets and side plates are used for fixing with bolts and nuts.

[0048] The two rigid plates are coupled by springs, and the rigid plates are coupled to the U-shaped moving platform. The connection points are all along the centerline of the width of the rigid plates, and all springs are arranged on the same horizontal plane.

[0049] The transmission part includes a lead screw drive mechanism, which includes a servo motor driver 24, a servo motor 12, a guide rail 17, and two sliders 16. The guide rail is located in the center of the experimental platform 18 and is arranged along the center line of the width direction of the experimental platform base. The U-shaped moving platform is located on the two sliders of the guide rail. The servo motor drives the sliders to drive the double-coupled "convex" structure to move in the horizontal direction.

[0050] The servo motor driver 24 is a product of THK, KR6525B_1340_1_10AV, with a ball screw lead of 25mm, a lead of 1340mm, and a total length of 1905mm.

[0051] Specifically, the servo motor 12 is a Mitsubishi Electric model HG-KN43 with a power of 400W, a maximum speed of 5000r / min, and a resolution of 131072 pulses / revolution. The servo motor driver 24 is a Mitsubishi MR-JE-40A driver.

[0052] The vibration detection section includes an accelerometer 1 and a piezoelectric fiber sensor 3.

[0053] The piezoelectric fiber sensor 3 is used to detect the vibration signal of the top flexible beam 2. It converts the vibration signal into a corresponding electrical signal output by its own sensing characteristics. After being amplified by the charge amplifier 22, it is transmitted to the motion control card 20 through the terminal board 23. Then, the analog signal is converted into a digital signal by the internal A / D conversion module and transmitted to the computer 19.

[0054] Accelerometer 1 is used to detect the vibration signal of the top flexible beam. After being amplified by charge amplifier 22, it is transmitted to motion control card 20 through terminal board 23. Then, the analog signal is converted into a digital signal by the A / D conversion module inside motion control card 20 and transmitted to computer 19.

[0055] Specifically, the piezoelectric fiber sensor 3 is made of piezoelectric ceramic, with geometric dimensions of 40mm×10mm×2mm. It is placed on the centerline of the width direction of the vertically placed top flexible beam 2, 100mm away from the upper edge of the right-angle bracket at the fixed end.

[0056] The accelerometer sensor 1 is a 4370 piezoelectric accelerometer from HBK Bruel & Kjaer, which is commonly used for vibration measurement and has a nominal sensitivity of 10 pc / ms. -2 The measurement frequency range is 0.1 to 4800 Hz, and it is arranged at the center line of the width direction of the top flexible beam 2, 20 mm away from the free end of the flexible beam.

[0057] The control unit includes:

[0058] Piezoelectric fiber sheet actuator 4 and amplified piezoelectric actuator 13.

[0059] The collected vibration signals are transmitted to computer 19 for processing. The computer runs an active control algorithm to generate corresponding control signals. The control signals are output by the Gogo motion controller through the DA output module of the terminal board, transmitted to the piezoelectric amplifier circuit 21 to amplify the signals, and output to the piezoelectric driver 4 and the amplified piezoelectric actuator 13, thereby suppressing the vibration of the flexible beam and the frame.

[0060] Specifically, an initial force is applied to the top flexible beam 2, and then the servo motor driver 24 is used to make the vibration of the entire mechanism more closely resemble the vibration of a flexible mechanism in space.

[0061] Specifically, the bending and torsion of the top flexible beam 2 are controlled by the piezoelectric fiber sheet actuator 4.

[0062] Specifically, the piezoelectric fiber sheet actuator 4 is placed on the vertically positioned top flexible beam 2 of the coupling frame near the fixed end of the right-angle bracket; wherein each top flexible beam 2 has four piezoelectric fiber sheet actuators, two on each side, which are symmetrical with respect to the center of the width direction, 40mm away from the upper edge of the right-angle bracket at the fixed end, with an orientation of 90°, and 20mm away from the edge line in the length direction, in order to suppress the bending vibration of the top flexible beam 2.

[0063] Specifically, the piezoelectric fiber sheet actuator 4 is made of piezoelectric ceramic material, with geometric dimensions of 60mm × 25mm × 2mm, and the elastic modulus of the piezoelectric ceramic is E. p =63GPa, d 31 = -166pm / V.

[0064] Specifically, the enlarged piezoelectric actuator 13 is set to a pre-tightened state, meaning that a displacement is pre-given in the long axis direction of the actuator. When the coupling frame 10 vibrates, the enlarged piezoelectric actuator will experience both compression and tension in the short axis direction. When the frame is compressed in the short axis direction, the internal support structure of the frame can counteract a large amplitude vibration. When the frame is stretched in the short axis direction, due to the change in the displacement signal, a certain voltage is applied to the actuator, causing the actuator's open-loop curve to correspond to the corresponding displacement. This causes the actuator to displace in the long axis direction, achieving inward drive along the short axis for control, thereby pulling the frame to counteract the tensile displacement.

[0065] Specifically, actuators are arranged side by side at the opening of the coupling frame 10, generating corresponding displacements at different positions to control the bending and torsion combination mode of the frame.

[0066] Specifically, the enlarged piezoelectric actuators 13 are located at the opening on the upper end face of the frame, with three actuators arranged symmetrically in each coupling frame, positioned along the midline of the side width at the opening, and the distance between the actuators is 52mm. The actuators are fixed to both sides and the opening with screws.

[0067] Specifically, the enlarged piezoelectric actuator 13 is the 115A10 product of Harbin Xinmingtian Technology Co., Ltd., with a length of 78.8mm, a width of 45mm, a thickness of 22.5mm, a driving voltage of 0~150V, and a nominal stroke range of 115μm±20%.

[0068] In this embodiment, the flexible beams are made of identical materials, all being thin sheets of epoxy resin. The dimensions of the top flexible beam 2 are 670mm × 200mm × 2mm, and the dimensions of the support beam 12 used to connect the rigid plate are 170mm × 70mm × 2mm. The elastic modulus of the epoxy resin is E. p =34.64 GPa, density is ρ = 1840 kg / m³ 3 .

[0069] The experimental table 18 is assembled from two aluminum profiles with lengths of 1996mm and 600mm respectively. The tabletop is a stainless steel plate of 2116mm×1906mm, which is connected to the profiles by screws. Each connection of the profiles is fixed with angle iron.

[0070] The charge amplifier 22 is the YE5850 charge amplifier from Jiangsu Lianeng Electronics Co., Ltd.; the motion control card 20 is the DMC-2x digital motion controller manufactured by GALIL Corporation of the United States, which provides a standard PCI bus interface; the selected computer 19 has a CPU model of Core 7 6650U 22.2GHz, 4G of memory, and a PCI-e slot on the motherboard, which can be used to install the motion control card.

[0071] The piezoelectric amplifier circuit 21 can be composed of components such as APEX-PA241DW or APEX-PA240CX piezoelectric amplifiers. It was developed by South China University of Technology and is described in detail in the applicant's patent application titled "Active Control Device and Method for Simulating Bending and Torsional Modal Vibration of Space Solar Panels," application number 200810027186.4. The amplification factor reaches 52 times, that is, amplifying -5V to +5V to -260V to +260V.

[0072] like Figure 10 As shown, a vibration measurement and control method for a dual-coupled convex platform moving flexible structure includes:

[0073] Step 1: The computer sends control signals to the servo motor driver to drive the servo motor, which in turn moves the "U"-shaped moving platform, further pulling the double-coupled "convex" structure, thereby causing the coupled frame and the top flexible beam to vibrate.

[0074] Step 2: Use a piezoelectric fiber sensor to detect the vibration of the flexible beam placed at the top of the coupling frame and obtain its measurement signal. Use an accelerometer unit to detect the vibration signal of the flexible beam at the top and obtain its vibration signal.

[0075] Step 3: The piezoelectric sensor signal and accelerometer signal acquired in Step 2 are processed by the charge amplifier and then transmitted to the motion control card through the terminal board. The analog signal is then converted into a digital signal by the A / D conversion module inside the motion control card and transmitted to the computer.

[0076] Step 4: The vibration detection signal obtained in step 3 is used to obtain the corresponding vibration feedback signal through the computer. The signal is then output by the D / A converter of the motion control card, transmitted through the terminal board, and amplified by the piezoelectric amplifier circuit before being output to the piezoelectric fiber driver and the amplified piezoelectric actuator, thereby suppressing the vibration of the flexible beam and frame.

[0077] Step 5: Adjust the algorithm parameters multiple times, conduct repeated experiments, and analyze the experimental results to obtain the vibration characteristics and control effect of the flexible beam.

[0078] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the embodiments described above. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A vibration monitoring and control device for a dual-coupled "convex" shaped platform motion flexible structure, characterized in that, include: The mobile platform body includes a U-shaped mobile platform. The base plate of the U-shaped mobile platform is provided with a double-coupled "convex" structure. The double-coupled "convex" structure includes a coupling frame and an upper structure. The upper structure includes a rigid plate. A top flexible beam is vertically placed on the upper end face of the rigid plate. The lower end face of the rigid plate is set on the coupling frame through a support beam. The rigid plates are coupled to each other and to the U-shaped mobile platform through springs. The springs are on the same horizontal plane. Transmission system: Drives the U-shaped moving platform to move horizontally, and during the movement, the vertical side plate of the coupling frame vibrates; Vibration detection section: used to detect vibration signals of the top flexible beam; Control section: Used to suppress the vibration of the flexible beam based on the detected vibration signal of the top flexible beam; The coupling frame is square, with an opening on the top surface. The sides of the coupling frame are treated with a ball end mill to form multiple concave semi-circular grooves. When moving horizontally, vibration is generated. The presence of the semi-circular grooves causes a change in the stiffness of the coupling frame, allowing the vibration to be transmitted within the frame and between the coupling frames. The coupling frame is internally supported by a support structure, which is specifically made of bent steel plate and fixed to the side plate of the coupling frame at both ends by right-angle brackets. The support beams consist of eight pieces, with each coupled "convex" structure comprising four pieces. The four support beams are symmetrically arranged with openings about the top surface and are placed vertically.

2. The vibration measurement and control device according to claim 1, characterized in that, The control unit includes a piezoelectric fiber sheet driver and an amplified piezoelectric actuator. The piezoelectric fiber sheet driver is mounted on the top flexible beam, and the amplified piezoelectric actuator is mounted at the opening of the coupling frame. After the computer receives the vibration signal, it generates a corresponding control signal, inputs it into the motion control card, outputs it through the terminal board, and after being amplified by the piezoelectric amplifier circuit, it is input to the piezoelectric fiber sheet and the piezoelectric actuator to suppress the vibration of the top flexible beam and the coupling frame.

3. The vibration measurement and control device according to claim 1, characterized in that, The vibration detection section includes a piezoelectric fiber sensor and an accelerometer. The piezoelectric fiber sensor and the accelerometer are installed on the top flexible beam to detect the vibration signal of the top flexible beam. After being amplified by a charge amplifier, the signal is transmitted to the motion control card through the terminal board and then input into the computer.

4. The vibration measurement and control device according to claim 1, characterized in that, The transmission component includes a servo motor driver, a servo motor, a guide rail, and sliders. The U-shaped moving platform is mounted on the guide rail via two sliders. The servo motor driver is connected to the servo motor to drive the U-shaped moving platform to move.

5. The vibration measurement and control device according to claim 1, characterized in that, The two coupling frames in the dual-coupling "convex" structure are symmetrically arranged inside the U-shaped moving platform, with a distance of 196mm between the two coupling frames.

6. The vibration measurement and control device according to claim 1, characterized in that, The spring is connected to the center line of the rigid plate.

7. The vibration measurement and control device according to claim 2, characterized in that, The enlarged piezoelectric actuators consist of three units.

8. A method based on the vibration measurement and control device according to any one of claims 1-7, characterized in that, Includes the following steps: Step 1: The computer sends control signals to the servo motor driver to drive the servo motor, which in turn moves the "U"-shaped moving platform, further pulling the double-coupled "convex" structure, thereby causing the coupled frame and the top flexible beam to vibrate. Step 2: Use a piezoelectric fiber sensor to detect the vibration of the flexible beam placed at the top of the coupling frame to obtain a measurement signal. Use an accelerometer unit to detect the vibration signal of the flexible beam at the top to obtain a vibration signal. Step 3: The collected piezoelectric sensor signals and accelerometer signals are processed by charge amplifiers and then transmitted to the motion control card through the terminal board. The analog signals are then converted into digital signals by the A / D conversion module inside the motion control card and transmitted to the computer. Step 4: The obtained vibration detection signal is processed by the computer to obtain the corresponding vibration feedback signal. The signal is then output by the D / A converter of the motion control card, transmitted through the terminal board, and amplified by the piezoelectric amplifier circuit before being output to the piezoelectric fiber driver and the amplified piezoelectric actuator, thereby suppressing the vibration of the top flexible beam and the frame. Step 5: Adjust the algorithm parameters multiple times, conduct repeated experiments, and analyze the experimental results to obtain the vibration characteristics and control effect of the flexible beam.

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