A vibration measurement and control device and method based on a compliant drive multibody coupling structure

Abstract

This invention discloses a vibration measurement and control device and method based on a compliant drive multi-body coupling structure, comprising: a compliant structure body, including an integrated compliant structure, which is connected to four flexible cantilever beams via connecting plates, and connected to an actuator. The integrated compliant structure reciprocates on a slide rail via a slider, and the actuator is connected to an AC servo motor; the ends of the four flexible cantilever beams are provided with different structures; a vibration detection section for detecting the vibration signals of the flexible cantilever beams; and a drive control section for obtaining control signals based on the vibration signals from the vibration detection section to suppress the vibration of the flexible cantilever beams. By fixing multiple flexible beams together to form a complete integrated compliant mechanism and coupling them, the influence of other uncontrollable factors on the vibration control effect is effectively eliminated.

Description

Technical Field

[0001] This invention relates to the field of vibration measurement of flexible structures, and in particular to a vibration measurement and control device and method based on a compliant driven multi-body coupling structure. Background Technology

[0002] Flexible multibody systems emerged as a research area in the 1970s, sparking considerable interest among researchers in mechanical and control engineering. Theoretical research and structural control of lightweight robots, spacecraft, and other structures are important applications of flexible multibody theory. These have significant practical implications for the development of my country's aerospace industry and related sectors.

[0003] Compared to traditional rigid structures, flexible structures offer advantages such as light weight and low energy consumption, leading to their widespread application in aerospace, robotics, robotic arms, and various other research and development fields. Simultaneously, as the future development of mechanical systems increasingly favors lightweight designs, the use of flexible multibody structures is significantly increasing. However, structural vibration is a pervasive phenomenon and a common problem closely studied in numerous engineering fields. Flexible structures have low stiffness and low damping, making them more susceptible to prolonged and large-amplitude vibrations when subjected to external factors, which are difficult to decay freely. Structural vibration generally has more disadvantages than advantages; for example, vibration not only affects the working accuracy of flexible multibody coupled structures but also accelerates the fatigue damage of the overall structure due to prolonged vibration during motion.

[0004] For example, the flexible structures of spacecraft and multi-degree-of-freedom robotic arms are mostly flexible multibody structures, many of which exhibit dense modal characteristics. Furthermore, the vibrations of each flexible body can couple and influence each other, easily leading to beat frequency vibrations. The vibration measurement and control of such flexible multibody systems warrants further research.

[0005] In conclusion, to ensure the normal operation of various flexible devices, it is imperative to study the vibration mechanism and control strategies of flexible structures. Establishing a detection system for flexible structures and analyzing their vibration characteristics is of significant practical engineering importance for subsequent research on suppression. Summary of the Invention

[0006] 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 based on a compliant drive multibody coupling structure.

[0007] The objective of this invention is achieved through the following technical solution:

[0008] A vibration monitoring and control device based on a compliant drive multibody coupling structure includes:

[0009] The compliant structure body includes an integrated compliant structure, which is connected to four flexible cantilever beams via connecting plates. The integrated compliant structure is connected to an actuator, and the integrated compliant structure reciprocates on a slide rail via a slider. The actuator is connected to an AC servo motor.

[0010] The ends of the four flexible cantilever beams are designed with different structures, so that the interaction between the flexible cantilever beams and the air and the fluid coupling of the air are different during the movement, resulting in different forms of external disturbance.

[0011] The vibration detection section is used to detect the vibration signals of the flexible cantilever beam;

[0012] The drive control section is used to obtain control signals based on the vibration signals from the vibration detection section to suppress the vibration of the flexible cantilever beam.

[0013] Furthermore, the vibration detection section includes piezoelectric sensors and accelerometers, both of which are mounted on the four flexible cantilever beams.

[0014] Furthermore, the piezoelectric sensor is used to detect the vibration of each flexible cantilever beam. It is set on the center line of the width direction of each flexible cantilever beam and is attached to both sides, with two sensors attached to each flexible cantilever beam.

[0015] Furthermore, the accelerometer is used to detect the vibration acceleration of each flexible cantilever beam. The accelerometer is set on the centerline of the width direction at the end of the flexible cantilever beam, and one is installed on each flexible cantilever beam.

[0016] Furthermore, the drive control section includes a piezoelectric actuator, a piezoelectric amplifier circuit, and a servo motor driver. The piezoelectric actuator is mounted on the flexible cantilever beam. The computer obtains the control quantities corresponding to the servo AC motor and the piezoelectric actuator based on the obtained vibration signal, and generates corresponding control signals. The control signals are output to the piezoelectric amplifier circuit and the servo motor driver through the motion control card and the terminal board, respectively, to further drive the AC servo motor and the piezoelectric actuator to control the vibration of the flexible cantilever beam.

[0017] Furthermore, different additional structures are provided at the ends of the four flexible cantilever beams, which are respectively the first flexible cantilever beam, the second flexible cantilever beam, the third flexible cantilever beam and the fourth flexible cantilever beam.

[0018] The end structure of the first flexible cantilever beam is as follows: the end edge of the first flexible cantilever beam is processed into a wave shape, the main body of the flexible cantilever beam and the wave shape form a T shape, and two rectangular thin plates are arranged parallel to each other at the upper and lower ends of the wave shape, and the rectangular thin plates are at an angle of 45 degrees to the flexible cantilever beam.

[0019] The end structure of the second flexible cantilever beam is specifically wavy. Compared with the end structure of the first flexible cantilever beam, its wavy shape has a smoother transition. Two rectangular thin plates extend from the upper and lower edges of the wavy shape. The two rectangular thin plates are arranged in parallel and form an angle of 45 degrees with the flexible cantilever beam.

[0020] The edge of the third flexible cantilever beam extends out a triangular structure, with all three corners of the triangle connected to a rectangular thin plate.

[0021] The edge of the fourth flexible cantilever beam extends into a triangular structure, which is rounded and connected to a rectangular thin plate at its three corners.

[0022] Furthermore, the first and second flexible cantilever beams are symmetrically arranged on both sides of the front end of the integrated compliant structure; the third and fourth flexible cantilever beams are symmetrically arranged on both sides of the rear end of the integrated compliant structure to form a compliant multi-body coupling structure.

[0023] Furthermore, the integrated compliant structure is connected to the slider via bearings and a stepped shaft.

[0024] A method based on the aforementioned vibration measurement and control device includes:

[0025] Step 1: Start and initialize each part of the device. The computer transmits data to the servo motor driver through the motion control card and terminal board, and finally drives the AC motor to produce the corresponding motion, causing the flexible beam to vibrate.

[0026] Step 2: Piezoelectric sensors and accelerometers detect the vibration and acceleration data of four flexible cantilever beams with different structures on the compliant structure.

[0027] Step 3: The piezoelectric sensor and accelerometer convert the detected information into vibration signals. The vibration signals collected by the vibration are amplified by the charge amplifier and transmitted to the terminal board. The terminal board then inputs the information into the motion control card. The A / D module inside the motion control card converts the analog signal into a digital signal for processing by the computer.

[0028] Furthermore, by controlling different movements of the AC servo motor, the working state of the vibration measurement and control device under different conditions can be simulated and the generated vibration can be controlled.

[0029] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0030] (1) Through reasonable mechanical structure design, the present invention fixes multiple flexible beams together to form a complete integrated compliant mechanism and couples them, effectively eliminating the influence of other uncontrollable factors on the vibration control effect;

[0031] (2) The present invention uses piezoelectric sensors and accelerometers to measure the strain information of flexible beams, which can quickly reflect the vibration information of multiple low-order modes of the robotic arm. Moreover, the structures of flexible cantilever beams are different, so the measured vibration information is richer and the measurement sensitivity is good.

[0032] (3) The present invention detects by measuring multiple positions of multi-mode. Compared with the prior art, its advantages are: simple system structure, easy to operate; multi-point detection, reducing experimental error, and improving measurement accuracy. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the vibration measurement and control device based on a compliant drive multibody coupling structure according to the present invention.

[0034] Figure 2 This is a side view of a vibration measurement and control device based on a compliant drive multibody coupling structure.

[0035] Figure 3 This is a top view of a vibration measurement and control device based on a compliant drive multibody coupling structure.

[0036] Figure 4 This is a front view of a vibration measurement and control device based on a compliant drive multibody coupling structure.

[0037] Figure 5 yes Figure 1 Schematic diagram of the motor and actuator;

[0038] Figure 6 yes Figure 1 A schematic diagram of the integrated flexible structure;

[0039] Figures 7(a)-7(d) are Figure 1 Schematic diagrams of four types of flexible cantilever beams;

[0040] Figure 8 This is the control flowchart of the present invention. Detailed Implementation

[0041] 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.

[0042] like Figures 1-6 As shown, a vibration measurement and control device based on a compliant drive multibody coupling structure includes:

[0043] The compliant structure body includes an integrated compliant structure 3, which is connected to four flexible cantilever beams 7 via connecting plates. The integrated compliant structure is connected to the actuator via bolts. The integrated compliant structure reciprocates on the slide rail 4 via a slider. The actuator is connected to an AC servo motor 2.

[0044] The actuator is driven by an AC servo motor and directly connected to an integrated compliant mechanism by bolts. The AC servo motor and the corresponding slide rails of the slider are fixedly connected to the experimental platform by bolts. This connection ensures that the main vibration detection area of ​​the cable-connected flexible structure is perpendicular to the experimental platform 1. The experimental platform is constructed of aluminum profiles and corner pieces, and the experimental platform plate is installed by screws.

[0045] An AC servo motor converts motion into linear motion via an actuator, thereby driving the device and providing a foundation for further vibration monitoring and control. The compliant structure is connected to the slider via bearings and a stepped shaft; during vibration monitoring and control, the compliant mechanism reciprocates on the slide rail via the connected slider.

[0046] Furthermore, the four flexible cantilever beams are connected at their initial ends to an integrated compliant structure, with different structures at their end edges. This causes each flexible cantilever beam to vibrate differently due to varying air resistance, enabling the study of vibration control in multiple shapes through a single experiment. This reduces the number of experiments, saving time and materials.

[0047] The four flexible cantilever beams 7 are the first flexible cantilever beam, the second flexible cantilever beam, the third flexible cantilever beam, and the fourth flexible cantilever beam.

[0048] As shown in Figures 7(a)-7(d), the end structure of the first flexible cantilever beam is specifically as follows: the end edge of the first flexible cantilever beam is processed into a wave shape, the main body of the flexible cantilever beam and the wave shape form a T-shape, and two rectangular thin plates are arranged parallel to each other at the upper and lower ends of the wave shape, with the rectangular thin plates forming an angle of 45 degrees with the flexible cantilever beam.

[0049] The end structure of the second flexible cantilever beam is specifically wavy. Compared with the end structure of the first flexible cantilever beam, its wavy shape has a smooth transition. Two rectangular thin plates extend from the upper and lower edges of the wavy shape. The two rectangular thin plates are arranged in parallel and have an angle of 45 degrees with the flexible cantilever beam.

[0050] The edge of the third flexible cantilever beam extends into a triangular structure, with all three corners of the triangle connected to a rectangular thin plate.

[0051] The edge of the fourth flexible cantilever beam extends into a triangular structure, which is rounded and connected to a rectangular thin plate at its three corners.

[0052] Further explanation: Compliant mechanisms accomplish specific tasks by storing and releasing energy through compliant units. They are novel mechanisms that utilize the elasticity of their components to transmit and convert motion and force. Unlike traditional rigid mechanisms that rely on kinematic pairs to achieve all motion and kinetic energy, they primarily rely on the deformation of flexible components within the mechanism to achieve its main motion and function. Because they actively utilize deformation to improve and enhance the mechanism's performance, they offer advantages such as reducing the number of components and assembly time, simplifying processing steps, eliminating friction and wear, and reducing transmission backlash, making them a hot topic in the field of mechanism research.

[0053] Specifically, the actuator is driven by the AC servo motor 2 and directly connected to the integrated compliant mechanism 3 by bolts. The AC servo motor 2 and the corresponding slide rail 4 of the slider are fixedly connected to the experimental platform 1 by bolts. This connection ensures that the main vibration detection area of ​​the cable-connected flexible structure is perpendicular to the experimental platform. The experimental platform 1 is constructed of aluminum profiles and corner pieces, and the experimental platform plate is installed by screws.

[0054] The four flexible cantilever beams 7, each with a different design shape, are symmetrically connected at different positions via L-shaped plates and an integrated compliant mechanism, forming a compliant multi-body coupled structure. When the overall experimental setup measures and controls vibration, an AC servo motor drives the movement of the entire compliant structure via an actuator.

[0055] The vibration detection section detects the vibration signals of the flexible beams and includes a piezoelectric sensor 6, an accelerometer 8, a charge amplifier 10, a terminal block 12, a motion control card 13, and a computer 14. The computer is interconnected with the motion control card, and the motion control card is interconnected with the terminal block. The piezoelectric sensor and the accelerometer are mounted on the four flexible cantilever beams of the integrated structure. The piezoelectric sensor detects the vibration of each flexible cantilever beam, and the accelerometer detects the vibration acceleration of each flexible cantilever beam. The signals from the piezoelectric sensor and the accelerometer are transmitted to the motion control card through the charge amplifier and the terminal block. The A / D module in the motion control card converts the analog signals into digital signals, which are then input to the computer.

[0056] Specifically, the piezoelectric sensors 6 are installed on the center lines of the width direction of the four flexible cantilever beams at different positions on the integrated structure, and are glued on both sides. Two sensors are glued to each flexible cantilever beam, for a total of 8 piezoelectric sensors.

[0057] Specifically, the accelerometer 8 is installed on the center line of the width direction of the four flexible cantilever beams at different positions on the integrated structure, and is connected by washers and nuts. One accelerometer is installed on each flexible cantilever beam, for a total of 4 accelerometer sensors.

[0058] The drive control section is used to suppress the vibration of the flexible beam and compliant structure based on the vibration signal from the detection section. The drive control section includes a piezoelectric actuator 5, a piezoelectric amplifier circuit 9, and a servo motor driver 11. The piezoelectric actuator is installed on the flexible beam. The computer obtains the control quantities corresponding to the servo AC motor and the piezoelectric actuator based on the obtained vibration signal, and generates corresponding control signals. The control signals are output to the piezoelectric amplifier circuit and the servo motor driver through the motion control card and the terminal board, respectively, to further drive the motor and the piezoelectric actuator to control the vibration of the flexible cantilever beam.

[0059] Specifically, the piezoelectric actuators are mounted on the center lines of the width direction of four flexible cantilever beams at different positions on the integrated structure, and are glued on both sides. Two piezoelectric actuators are glued to each flexible cantilever beam, for a total of eight piezoelectric actuator sensors.

[0060] like Figure 8 As shown, a control method for a vibration monitoring and control device of a multi-structure, multi-flexible beam coupled structure includes the following steps:

[0061] Step 1: Start and initialize each part of the device. The computer transmits data to the servo motor driver through the motion control card and terminal board, and finally drives the AC motor to produce the corresponding motion, causing the flexible beam to vibrate.

[0062] Step 2: Piezoelectric sensors and accelerometers detect the vibration and acceleration data of four flexible cantilever beams with different structures on the compliant structure.

[0063] Step 3: The piezoelectric sensor and accelerometer convert the detected information into vibration signals. The vibration signals collected by the vibration are amplified by the charge amplifier and transmitted to the terminal board. The terminal board then inputs the information into the motion control card. The A / D module inside the motion control card converts the analog signal into a digital signal for processing by the computer.

[0064] Step 4: After processing the vibration signal, the computer generates the required vibration control signal. The control signal is then output in reverse through the motion control card and terminal board to the piezoelectric amplifier circuit and servo motor driver, which further drive the AC servo motor and piezoelectric driver to control the vibration of the flexible cantilever beam.

[0065] Step 5: Control the movement of the AC servo motor by continuously changing the parameters. Through repeated experiments, obtain multiple experimental results to find the optimal control parameters required for the experimental device.

[0066] By controlling different movements of the AC motor, the working state of the vibration measurement and control device under different conditions can be simulated and the generated vibration can be controlled.

[0067] In this embodiment,

[0068] Specifically, in this embodiment, the experimental platform is assembled from two aluminum profiles with lengths of 6000mm and 200mm respectively. The platform is a stainless steel plate of 1400mm×500mm×10mm, which is connected to the profiles by screws. Each connection of the profiles is fixed with angle iron.

[0069] Specifically, regarding the selection of the motor, the Mitsubishi Electric HF-KN13 low-inertia, small-capacity motor is used in this device, with a rated output power of 100W and a maximum speed of 4500r / min.

[0070] Specifically, the actuator selected is a THK KSF4 electric actuator with a ball screw lead of 10mm and a travel distance of 50mm.

[0071] Specifically, in this embodiment, the four flexible beams are made of epoxy resin sheets with geometric dimensions of 500mm×50mm×2mm, an elastic modulus of Ep=26.8Gpa, and a density of ρ=1980kg / m3.

[0072] Specifically, in this embodiment, an MFC actuator and sensor are selected. This is a piezoelectric macrofiber composite material, composed of interdigitated electrodes, a polyimide film, structural epoxy resin, and rectangular piezoelectric fibers bonded together. The model used here is MFC2814-P1, with overall geometric dimensions of 38mm × 20mm × 0.6mm and actuation dimensions of 28mm × 14mm × 0.3mm. It is bonded in sheet form to the flexible cantilever beam, and is symmetrical about the centerline of the flexible cantilever beam's width direction. The elastic modulus of the MFC material is Em = 48.3 GPa, and d33 = 436 pm / V.

[0073] Specifically, in this embodiment, the accelerometer selected is the HBK Bruel & Kjaer vibration sensor model 4370 piezoelectric charge accelerometer, which is used for vibration measurement, has a nominal sensitivity of 10 pc / ms^(-2), and a measurement frequency range of 0.1~4800Hz.

[0074] Specifically, the sliders and guide rails are THK's LM wide guide rails with ball bearing grease rings, model SHW21CA3SS+780L. All four sliders are SHW model, size 21, type CA; they have flanges, a rail length of 780mm, and use AFF (lithium-based) grease for clean environments. The slider bolts are M5, the guide rail bolts are M4, and the total weight is 2.98kg.

[0075] Specifically, the charge amplifier selected is the YE5850 charge amplifier from Jiangsu Lianeng Electronics Co., Ltd.; the piezoelectric amplifier circuit uses the APEX-PA241DW piezoelectric amplifier, which has a magnification factor of up to 52 times and can amplify -5V to +5V to -260V to +260V.

[0076] Specifically, the motion control card selected is the GUC-800-TPV-M23-L2-F8G model from Googol Technology, which can provide analog input and output with a range of -10V to +10V for 8 controllable axes; the selected computer CPU is Pentium G620 2.6GHz, with 4G of memory, and the motherboard has a PCI interface to install the motion control card.

[0077] Figure 1 The dashed lines indicate the connections between the various devices, and the directional arrows indicate the direction of transmission of detection and control signal flows.

[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 measurement and control device based on a compliant drive multi-body coupling structure, characterized in that, include: The compliant structure body includes an integrated compliant structure, which is connected to four flexible cantilever beams via connecting plates. The integrated compliant structure is connected to an actuator, and the integrated compliant structure reciprocates on a slide rail via a slider. The actuator is connected to an AC servo motor. The ends of the four flexible cantilever beams are designed with different structures, so that the interaction between the flexible cantilever beams and the air and the fluid coupling of the air are different during the movement, resulting in different forms of external disturbance. The vibration detection section is used to detect the vibration signals of the flexible cantilever beam; The drive control section is used to obtain control signals based on the vibration signals from the vibration detection section to suppress the vibration of the flexible cantilever beam. The ends of the four flexible cantilever beams are provided with different additional structures. The four flexible cantilever beams are the first flexible cantilever beam, the second flexible cantilever beam, the third flexible cantilever beam and the fourth flexible cantilever beam. The end edge of the first flexible cantilever beam is processed into a wave shape, and the main body of the flexible cantilever beam and the wave shape form a T-shape. Two rectangular thin plates are arranged parallel to each other at the upper and lower ends of the wave shape, and the rectangular thin plates are at an angle of 45 degrees to the flexible cantilever beam. The end structure of the second flexible cantilever beam is wavy. Compared with the end structure of the first flexible cantilever beam, its wavy shape has a smooth transition. Two rectangular thin plates extend from the upper and lower edges of the wavy shape. The two rectangular thin plates are arranged in parallel and have an angle of 45 degrees with the flexible cantilever beam. The edge of the third flexible cantilever beam extends out a triangular structure, with all three corners of the triangle connected to a rectangular thin plate. The edge of the fourth flexible cantilever beam extends into a triangular structure, which is rounded and the three corners of the triangular structure are connected to a rectangular thin plate. The first and second flexible cantilever beams are symmetrically arranged on both sides of the front end of the integrated compliant structure; the third and fourth flexible cantilever beams are symmetrically arranged on both sides of the rear end of the integrated compliant structure to form a compliant multi-body coupling structure. The integrated compliant structure is connected to the slider via bearings and a stepped shaft.

2. The vibration measurement and control device according to claim 1, characterized in that, The vibration detection section includes piezoelectric sensors and accelerometers, both of which are mounted on four flexible cantilever beams. The piezoelectric sensor is used to detect the vibration of each flexible cantilever beam. It is set on the center line of the width direction of each flexible cantilever beam and is attached to both sides. Two piezoelectric sensors are attached to each flexible cantilever beam. The accelerometer is used to detect the vibration acceleration of each flexible cantilever beam. The accelerometer is set on the centerline of the width direction at the end of the flexible cantilever beam, and one is installed on each flexible cantilever beam.

3. The vibration measurement and control device according to claim 1, characterized in that, The drive control section includes a piezoelectric actuator, a piezoelectric amplifier circuit, and a servo motor driver. The piezoelectric actuator is mounted on the flexible cantilever beam. The computer obtains the control quantities corresponding to the AC servo motor and the piezoelectric actuator based on the obtained vibration signal, and generates corresponding control signals. The control signals are output to the piezoelectric amplifier circuit and the servo motor driver through the motion control card and terminal board, respectively, to further drive the AC servo motor and the piezoelectric actuator and control the vibration of the flexible cantilever beam.

4. A method based on the vibration measurement and control device according to any one of claims 1-3, characterized in that, include: Step 1: Start and initialize each part of the device. The computer's control signal is transmitted to the servo motor driver through the motion control card and terminal board, and finally drives the AC servo motor to produce the corresponding motion, causing the flexible beam to vibrate. Step 2: Piezoelectric sensors and accelerometers detect the vibration and acceleration data of four flexible cantilever beams with different structures on the compliant structure. Step 3: The piezoelectric sensor and accelerometer convert the detected information into vibration signals. The vibration signals are amplified by the charge amplifier and transmitted to the terminal board. The terminal board then inputs the information into the motion control card. The A / D module inside the motion control card converts the analog signal into a digital signal for processing by the computer.

5. The method according to claim 4, characterized in that, By controlling different movements of the AC servo motor, the working state of the vibration measurement and control device under different conditions can be simulated and the generated vibration can be controlled.

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