A flexible joint-based multi-flexible L-shaped beam vibration measurement and control device and method

Abstract

The application discloses a kind of based on flexible joint's multi-flexible L-shaped beam vibration measurement and control device and method, including multi-flexible L-shaped beam body, vibration part, vibration detection part and vibration control part;The multi-flexible L-shaped beam body part includes two by torsion spring and is constituted flexible joint, two lower inclined convex arc L-shaped flexible beam, two lower inclined concave arc L-shaped flexible beam, two upper inclined convex arc L-shaped flexible beam, two upper inclined concave arc L-shaped flexible beam, eight flexible beams are installed on two flexible joints by clamping frame and are divided into upper and lower two layers, adjacent flexible beam is connected by tension spring, and flexible beam end is immersed in water in water tank.The measurement and control device of the application becomes more diversified and complex after adding flexible joint, tension spring and water tank propeller driving device, greatly increases the difficulty of vibration characteristic analysis and active control research, realizes the vibration characteristic analysis and active control of multi-rotation multi-flexible L-shaped beam.

Description

Technical Field

[0001] This invention relates to the field of vibration control of flexible cantilever beams, and particularly to a vibration measurement and control device and method for a multi-flexible L-shaped beam based on flexible joints. Background Technology

[0002] Underwater robots are extreme operational robots that work underwater. Given the harsh and dangerous underwater environment and the limited diving depth of humans, underwater robots have become crucial tools for ocean exploration. Flexible materials, with their lightweight, low energy consumption, and low load-bearing ratio, are widely used in robotics. Furthermore, to meet the demands of underwater operations, multi-flexible coupling structures, such as flexible robotic arms, are designed and applied to underwater robots. However, the low natural frequencies of flexible structures make them susceptible to low-frequency coupled vibrations, limiting their development. Therefore, to ensure the mission accuracy of underwater robots, the vibration characteristic analysis and active control research of multi-flexible coupling structures in underwater environments has become a global research hotspot.

[0003] Servo motors are characterized by high precision, fast response, and good dynamic characteristics. The output of a servo motor can both excite and suppress the vibration of a flexible beam.

[0004] Piezoelectric ceramic sheets are characterized by their simple structure, convenient installation, and long lifespan. Using piezoelectric ceramic sheets for vibration detection and control is the main choice for research on flexible beams. Summary of the Invention

[0005] 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 multi-flexible L-shaped beams based on flexible joints. After adding flexible joints, tension springs and water tank propeller drive devices, the measurement and control device of this invention becomes more diversified and complex, which greatly increases the difficulty of vibration characteristic analysis and active control research, and realizes the vibration characteristic analysis and active control of multi-rotation and multi-flexible L-shaped beams.

[0006] The objective of this invention is achieved through the following technical solution:

[0007] A vibration monitoring and control device for a multi-flexible L-shaped beam based on flexible joints includes a multi-flexible L-shaped beam body, a vibration part, a vibration detection part, and a vibration control part.

[0008] The main body of the multi-flexible L-shaped beam includes an upper flexible joint. The lower end of the upper flexible joint is connected to the upper clamping frame. The upper clamping frame is equipped with four flexible beams. The four flexible beams are installed horizontally, facing four different directions: front, back, left, and right. Specifically, they include two downward-sloping convex L-shaped flexible beams and two downward-sloping concave L-shaped flexible beams. One end of each of the four flexible beams is connected to the upper clamping frame through a clamping plate, which is called the fixed end. The other end is the free end.

[0009] It also includes a lower flexible joint, the upper end of which is connected to the upper clamping frame, and the lower end of which is connected to the lower clamping frame. The lower clamping frame is fixedly installed with four flexible beams. The four flexible beams are installed horizontally, facing four different directions: front, back, left, and right. Specifically, they include two upwardly inclined convex L-shaped flexible beams and two upwardly inclined concave L-shaped flexible beams. One end of each of the four flexible beams is connected to the lower clamping frame through a clamping plate, which is called the fixed end, and the other end is the free end.

[0010] Tension springs are installed between adjacent flexible beams, and the free ends of the flexible beams extend into the water tank and are partially immersed in the liquid in the water tank;

[0011] The vibration section includes a first servo motor vibration section and an underwater propeller vibration section. The first servo motor vibration section is used to drive the upper flexible joint to move, and further drive the flexible beam to rotate. The underwater propeller vibration section is used to drive the vibration of a portion of the flexible beam immersed in the liquid in the tank.

[0012] The vibration detection section is used to detect the vibration signal of the flexible beam;

[0013] The vibration control section is used to suppress the vibration of the flexible beam.

[0014] Furthermore, the vibration excitation part of the first servo motor includes a first servo motor and a first reducer. The bottom ends of the first servo motor and the first reducer are connected to each other, and the output shaft of the reducer is connected to the upper flexible joint.

[0015] Furthermore, the upper and lower flexible joints have the same structure, including two torsion springs and a sleeve. The two torsion springs are set at the upper and lower ends of the reducer output shaft. One end of the torsion spring is connected to the reducer output shaft, and the other end is connected to the sleeve. The two torsion springs are installed in opposite directions. The sleeve and the reducer output shaft are connected to each other through the torsion springs and tapered roller bearings to form a flexible joint.

[0016] Furthermore, the underwater propeller vibration part includes a propeller, a reducer connecting platform, a second reducer, a second servo motor, and a mounting bracket. The propeller is installed at the bottom of the water tank, and the propeller is connected to the second reducer through the reducer connecting platform. The second servo motor is connected to the second reducer.

[0017] Furthermore, the included angle between identical flexible beams is 180 degrees, and the included angle between adjacent flexible beams is 90 degrees.

[0018] Furthermore, the vibration detection section includes a piezoelectric ceramic sensor, which is installed on the flexible beam. Each flexible beam has one piezoelectric ceramic sensor. The piezoelectric ceramic sensor detects the vibration signal, which is amplified by a charge amplifier and then input to a terminal board. The terminal board then inputs the signal to a motion control card. The A / D module in the motion control card converts the analog signal into a digital signal, which is finally input to the computer.

[0019] Furthermore, the vibration control section includes a piezoelectric actuator. The computer calculates the control quantities corresponding to the first servo motor, the second servo motor, and the piezoelectric actuator based on the vibration detection signal, generates corresponding control signals, and drives the first servo motor, the second servo motor, and the piezoelectric actuator to suppress the vibration of the flexible beam.

[0020] Furthermore, the propeller has eight blades, which are evenly distributed along a 360° circumference.

[0021] Furthermore, the piezoelectric actuator comprises 32 pieces, with 4 piezoelectric actuators installed on each flexible beam, two pieces on each side, symmetrically installed and connected in parallel.

[0022] A vibration monitoring and control device for a flexible L-shaped beam includes the following steps:

[0023] Step 1: The first servo motor drives the excitation part to cause the flexible beam to vibrate; the underwater propeller vibration excitation part stirs the water in the tank in a specified direction, thereby causing the flexible beam submerged in the water to vibrate.

[0024] Step 2: The vibration detection section inputs the vibration signal of the flexible beam into the computer;

[0025] Step 3: The computer receives the vibration signal and processes it. After running the control algorithm, it calculates the control quantities corresponding to the first and second servo motors and piezoelectric actuators, and generates corresponding control signals to further suppress the vibration of the flexible beam.

[0026] Step 4: By changing the control parameters of the control algorithm and conducting repeated experiments, multiple experimental results are obtained to determine the vibration characteristics and control effect of a flexible joint-driven multi-flexible L-shaped beam vibration measurement and control device and method.

[0027] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0028] (1) This invention designs a flexible beam structure with different shapes clamped in two layers. Flexible joints are designed between the servo motor and the upper clamping layer, and between the upper and lower clamping layers. The nonlinearity of these flexible joints results in nonlinear and time-delayed transmission of rotational force between the servo motor and the upper and lower clamping layers, leading to a nonlinear relationship in rotational speed. The flexible joints give the entire system stronger nonlinearity, time-delay, and coupling characteristics.

[0029] (2) The present invention designs a spring connection between the adjacent flexible beams of the upper and lower clamping layers. The flexible joint makes the upper and lower clamping layers have a strong nonlinear and coupling relationship in terms of rotation speed. The tension spring connects the adjacent flexible beams, making all the flexible beams have a more direct and stronger coupling relationship, which makes the vibration characteristics of the system more complex and increases the difficulty of active vibration control.

[0030] (3) This invention designs a water tank and an underwater propeller drive device. A servo motor drives a propeller installed in the water tank to rotate. The propeller stirs the water in the tank, generating waves, which in turn excites the vibration of the flexible beam. Simultaneously, during the vibration of the flexible beam, the water generates nonlinear fluid resistance on the submerged flexible beam, further increasing the nonlinearity and uncertainty of the system. Furthermore, the immersion depth of the flexible beam can be adjusted by changing the water level in the tank, thereby studying the influence of different immersion depths on the system's vibration characteristics and active control effect. The type of liquid in the tank can be changed to study the vibration characteristics and active control effect of the entire system immersed in liquids with different properties.

[0031] (4) This invention improves the overall stability of the structure by designing and optimizing the trajectory of the servo motor;

[0032] (5) The present invention optimizes the installation position of the piezoelectric ceramic sensor and the piezoelectric actuator based on the basic shape and size of the flexible beam, thereby improving the measurement effect of the piezoelectric ceramic sensor and the control effect of the piezoelectric actuator. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the overall structure of the device of the present invention.

[0034] Figure 2 yes Figure 1 The main view;

[0035] Figure 3 yes Figure 1 The left view;

[0036] Figure 4 yes Figure 1 Top view;

[0037] Figure 5yes Figure 1 Schematic diagram of the upper and middle layer clamping frames and the lower layer clamping frame clamping the flexible beam;

[0038] Figure 6 yes Figure 1 Schematic diagram of the mid-water tank and underwater propeller drive device;

[0039] Figure 7 yes Figure 1 Schematic diagram of a moderately flexible joint;

[0040] Figure 8 yes Figure 1 Schematic diagram of a medium-sized propeller;

[0041] Figure 9 This is a schematic diagram of the sleeve;

[0042] Figure 10 This is the control flowchart of the present invention. Detailed Implementation

[0043] 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.

[0044] like Figures 1-9 As shown, a vibration measurement and control device for a multi-flexible L-shaped beam based on flexible joints includes a multi-flexible L-shaped beam body, a vibration part, a vibration detection part, and a vibration control part.

[0045] The multi-flexible L-shaped beam body includes an upper flexible joint 4, an upper clamping frame 5, a small clamping plate 6, a tension spring 7, a lower flexible joint 10, a lower clamping frame 11, a small clamping plate 12, a downward convex L-shaped flexible beam 19, a downward concave L-shaped flexible beam 20, a downward convex L-shaped flexible beam 21, a downward concave L-shaped flexible beam 22, an upward convex L-shaped flexible beam 23, an upward concave L-shaped flexible beam 24, an upward convex L-shaped flexible beam 25, and an upward concave L-shaped flexible beam 26.

[0046] like Figure 5 As shown, it includes an upper flexible joint 4. The lower end of the upper flexible joint 4 is connected to the upper clamping frame 5. The upper clamping frame 5 is equipped with four flexible beams. The four flexible beams are installed horizontally, facing four different directions: front, back, left, and right. Specifically, it includes two downward convex L-shaped flexible beams 19 and 21 and two downward concave L-shaped flexible beams 20 and 22. One end of the four flexible beams is connected to the upper clamping frame 5 through a small clamping plate 6, which is called the fixed end, and the other end is the free end.

[0047] It also includes a lower flexible joint 10, the upper end of which is connected to the upper clamping frame 5, and the lower end of which is connected to the lower clamping frame 11. The lower clamping frame 11 is fixedly equipped with four flexible beams, which are installed horizontally and face four different directions: front, back, left, and right. Specifically, it includes two upwardly inclined convex L-shaped flexible beams 23 and 25 and two upwardly inclined concave L-shaped flexible beams 24 and 26. One end of the four flexible beams is connected to the lower clamping frame 11 through a small clamping plate 12, which is called the fixed end, and the other end is the free end.

[0048] Eight flexible beams form a propeller shape, and tension springs 7 are installed between adjacent flexible beams. The free ends of the flexible beams extend into the water tank 27 and are partially immersed in the liquid in the water tank.

[0049] Furthermore, all the flexible beams are L-shaped beams, including a vertical portion and a horizontal portion, with the vertical portion extending into the water tank. The four flexible beams mounted on the upper clamping frame intersect perpendicularly with the four flexible beams mounted on the lower clamping frame, specifically, the concave and convex shapes of the vertical portions intersect each other.

[0050] Specifically, the horizontal portion of the L-shaped beam is a rectangular beam, while the vertical portion is either concave or convex, which corresponds to the shape of the free-end blades. The concave shape refers to cutting inwards to form a concave arc, while the convex shape refers to cutting outwards to form a convex arc. The upward angle of the upward-sloping convex flexible beam and the upward-sloping concave flexible beam is 20°, and the distance from the upper end to the lower end is 526mm. The radius of the arc corresponding to the convex portion of the upward-sloping convex flexible beam is 400mm, and the central angle is 61°. The radius of the arc corresponding to the convex portion of the upward-sloping concave flexible beam is 1795mm, and the central angle is 13°. The upward inclination angle of the downward convex flexible beam and the downward concave flexible beam is 20°, and the distance from the upper end point to the lower end point is 400mm. The radius of the arc corresponding to the convex part of the downward convex flexible beam is 347mm, and the central angle is 60°. The radius of the arc corresponding to the convex part of the downward concave flexible beam is 958mm, and the central angle is 20°.

[0051] Furthermore, the two identical flexible beams have an included angle of 180 degrees.

[0052] Furthermore, the upper and lower adjacent flexible beams are connected by tension springs 7. The tension springs are fixedly connected to the flexible beams by lifting rings. The fixed position is on the centerline of the flexible beam installation section. For the upper inclined convex arc L-shaped flexible beam and the upper inclined concave arc L-shaped flexible beam, the distance from the uppermost vertex of the fixed end edge of the flexible beam is 398mm. For the lower inclined convex arc L-shaped flexible beam and the lower inclined concave arc L-shaped flexible beam, the distance from the uppermost vertex of the fixed end edge of the flexible beam is 365mm.

[0053] The vibration components include a first servo motor vibration component and an underwater propeller vibration component.

[0054] The vibration part of the first servo motor includes a first reducer 3 and a first servo motor 2. The first reducer 3 is fixedly installed on the support frame 1. The bottom ends of the first servo motor and the first reducer 3 are connected to each other. The output shaft 18 of the reducer is connected to the upper flexible joint 4.

[0055] The upper flexible joint 4 and the lower flexible joint 10 have the same structure, specifically:

[0056] Torsion springs 14 and 17 are respectively installed at the upper and lower ends of the reducer output shaft 18. One end of the torsion spring is fixedly connected to the slot on the reducer output shaft 18, and the other end is fixedly connected to the hole on the sleeve 13. The upper and lower ends of the torsion spring are installed in opposite directions. Tapered roller bearings 15 and 16 are installed at both ends of the shoulder at the middle position of the reducer output shaft 18. The two tapered roller bearings are positioned and installed through the boss on the inner wall of the sleeve 13 and the shoulder of the reducer output shaft 18. The sleeve and the reducer output shaft are connected to each other through the torsion spring and the tapered roller bearing to form a flexible joint.

[0057] The first servo motor 2 drives the first reducer 3 to rotate, which in turn drives the flexible joint 4 connected to the first reducer to rotate. The sleeve 13 in the flexible joint is connected to the output shaft 18 of the reducer through torsion springs 14 and 17. The output shaft drives the sleeve to rotate through the torsion springs. The sleeve 13 drives the upper clamping frame 5 and the four flexible beams fixedly installed on it to rotate. The lower flexible joint 10 rotates through the drive of the upper clamping frame 5, which in turn drives the lower clamping frame 11 and the four flexible beams fixed on it to rotate.

[0058] The underwater propeller vibration component includes:

[0059] Water tank 27, propeller 28, reducer connection platform 29, second reducer 30, second servo motor 31, mounting bracket 32, and water tank support platform 33.

[0060] The water tank 27 is placed on the water tank support platform 33, the second reducer 30 is fixedly installed on the mounting bracket 32, the second servo motor 31 is connected to the second reducer 30, the propeller 28 is connected to the second reducer 30 through the reducer connection platform 29, and the propeller 28 is installed at the bottom of the water tank 27.

[0061] The second servo motor 31 drives the second reducer 30 to rotate. The second reducer 30 drives the propeller 28 to rotate via the reducer connecting platform 29. The propeller 28 rotates in the water, thus agitating the water. The free ends of the eight flexible beams are submerged in the water tank 27. The water ripples due to the agitation of the propeller 28, thereby exciting the submerged flexible beams to vibrate. The water level in the tank 27 can be adjusted to achieve different immersion heights for the flexible beams, allowing for the study of the vibration characteristics and control methods of the flexible beams submerged at different depths of water. Furthermore, the water in the tank 27 can be replaced with other liquids to study the vibration characteristics and control methods of the flexible beams submerged in liquids with different properties.

[0062] Furthermore, such as Figure 6 As shown, the water tank 27 is a circular water tank with a diameter of 1140mm. The center line of the water tank 27 coincides with the center line of the lower clamping frame 11. The water tank is placed on the water tank support platform 33.

[0063] Furthermore, such as Figure 7 As shown, the two torsion springs 14 and 17 are installed in opposite directions and are horizontally pre-tightened. The upper torsion spring 14 is installed 8mm away from the free end of the output shaft, and the lower torsion spring 17 is installed 43mm away from the free end of the output shaft. The lower end connecting hole of the sleeve 13 is 5mm away from the bottom end of the sleeve, and the upper end connecting hole of the sleeve is 58mm away from the bottom end of the sleeve. The diameter of the connecting hole is 1mm.

[0064] like Figure 8 As shown, the propeller has 8 blades, evenly distributed along a 360° circumference. The propeller is installed at the center of the water tank, with the bottom of the propeller 60mm from the bottom of the water tank.

[0065] like Figure 9 As shown, the complete sleeve is composed of two half sleeves spliced ​​together. The lower end connecting hole of sleeve 6 is 3mm from the bottom end of the sleeve, and the upper end connecting hole is 56mm from the bottom end of the sleeve. The diameter of the connecting hole is 1mm. The top of the sleeve has 4 M6 threaded holes.

[0066] The vibration detection section includes:

[0067] 9. Piezoelectric ceramic sensor, 36. Charge amplifier, 37. Terminal board, 38. Motion control card, and 39. Computer.

[0068] The computer 39 is interconnected with the motion control card 38, and the motion control card 38 is interconnected with the terminal board 37. The piezoelectric ceramic sensor 9 is installed on the flexible beam. The piezoelectric ceramic sensor 9 detects vibration signals, which are amplified by the charge amplifier 36 and then input to the terminal board 37. The signal is then input to the motion control card 38 through the terminal board 37. The A / D module in the motion control card converts the analog signal into a digital signal, which is then input to the computer 39.

[0069] Furthermore, the piezoelectric ceramic sensor comprises 8 pieces, with one piezoelectric ceramic sensor 9 installed near the fixed end of each flexible beam. The sensor is installed on one side of the centerline of the flexible beam installation section, with the installation position 120mm away from the uppermost vertex of the edge line of the fixed end of the flexible beam. The installation direction is parallel to the centerline of the flexible beam installation section, and it is used to detect the vibration of the flexible beam.

[0070] The vibration control section includes:

[0071] The components include: a piezoelectric actuator 8, a first servo motor 2, a second servo motor 31, a piezoelectric amplifier 34, a servo driver 35, a charge amplifier 36, a terminal block 37, a motion control card 38, and a computer 39.

[0072] The computer 39 is interconnected with the motion control card 38, and the motion control card 38 is interconnected with the terminal board 37. The piezoelectric actuator 8 is mounted on the flexible beam. Vibration excitation can be performed in two ways: First, the first servo motor 2 drives the upper flexible joint 4 to rotate via the first reducer 3. The upper flexible joint 4 then drives the upper clamping frame 5, the flexible beam mounted on the upper clamping frame 5, and the lower flexible joint 10 connected to the upper clamping frame 5 to rotate, thereby driving the clamping frame and the flexible beam mounted on the upper clamping frame 5 to rotate. The flexible beam rotates, generating vibration. Second, the second servo motor 31 drives the propeller to rotate via the reducer. The rotating propeller agitates the water in the water tank 27, thereby causing the flexible beam, whose free end is submerged in the water, to vibrate. Based on the vibration signals detected by the vibration detection unit, the computer runs a control algorithm to calculate the control quantities corresponding to the first servo motor 2, the second servo motor 31, and the piezoelectric actuator 8, and generates corresponding control signals. The control signals corresponding to the first servo motor 2 and the second servo motor 31 are output to the motion control card 38 through the computer, then to the terminal board 37, and finally to the servo driver 35 to drive the first servo motor 2 and the second servo motor 31 to control the vibration of the flexible beam. The control signal corresponding to the piezoelectric actuator 8 is output to the motion control card through the computer 39, then to the terminal board 37 and the piezoelectric amplifier 34, and finally to the piezoelectric actuator 8, which controls the vibration of the flexible beam.

[0073] Specifically, the piezoelectric actuator 8 comprises 32 pieces, with 4 pieces of piezoelectric actuator 8 installed on each flexible beam, two pieces on each side, symmetrically installed and connected in parallel. The installation position is 50mm away from the uppermost vertex of the fixed end edge of the flexible beam. The two piezoelectric actuators 8 on each side are symmetrically installed 20mm away from the center line, and the installation direction is parallel to the center line of the flexible beam installation section, which is used to suppress the vibration of the flexible beam.

[0074] like Figure 10As shown, a control method for a flexible L-shaped beam vibration monitoring and control device driven by a flexible joint includes the following steps:

[0075] Step 1: Computer 39 outputs the designed trajectory signal I, which is transmitted to servo driver 35 via motion control card 38 and terminal board 37. This drives the first servo motor 2 to rotate, causing the entire flexible beam coupling structure to rotate and vibrate. Computer 39 also outputs the designed trajectory signal II, which is transmitted to servo driver 35 via motion control card 38 and terminal board 37. This drives the second servo motor 31 to rotate, causing propeller 28 to move. Propeller 28 stirs the water in tank 27 in a specified direction, thereby causing the flexible beam submerged in the water to vibrate.

[0076] Step 2: The vibration information of the flexible beam is collected by the piezoelectric ceramic sensor 9 attached to the flexible beam, and the vibration signal is output. The collected vibration signal is transmitted to the motion control card 38 through the charge amplifier 36 and the terminal board 37. The A / D conversion module inside the motion control card 38 converts the analog signal into a digital signal and inputs it into the computer 39.

[0077] Step 3: The computer 39 receives and processes the vibration signal, runs the control algorithm, calculates the control quantities corresponding to the first servo motor 2 and the piezoelectric actuator 8, and generates corresponding control signals. The control signals are output to the motion control card 38 through the computer 39. The D / A conversion module in the motion control card 38 converts the digital signal into an analog signal. The control signal of the first servo motor 2 is transmitted through the terminal board 37 and the servo driver 35, and finally acts on the first servo motor 2 to suppress the vibration of the flexible beam. The control signal of the piezoelectric actuator 8 is transmitted through the terminal board 37 and the piezoelectric amplifier 34, and finally to the piezoelectric actuator 8, which suppresses the vibration of the flexible beam.

[0078] Step 4: By changing the control parameters of the control algorithm and conducting repeated experiments, multiple experimental results are obtained to determine the vibration characteristics and control effect of a flexible joint-driven multi-flexible L-shaped beam vibration measurement and control device and method.

[0079] Figure 1 The dashed lines and arrows in the diagram indicate the signal transmission direction and the connection relationship between devices.

[0080] In this embodiment, the eight flexible beams are made of epoxy resin sheets with an elastic modulus of Ep = 26.8 GPa and a density of ρ = 1980 kg / m³. 3 .

[0081] The piezoelectric ceramic sensor and piezoelectric actuator are both made of piezoelectric ceramic. The piezoelectric ceramic sensor measures 25mm × 10mm × 1mm, and the piezoelectric actuator measures 50mm × 20mm × 1mm. Both are sheet-like and bonded to the flexible beam. The elastic modulus and piezoelectric strain constant of the piezoelectric ceramic are Ep = 63 GPa and d31 = 166 pm / V, respectively.

[0082] The servo motor is a Mitsubishi Electric HC-KFS43 AC servo motor with a power of 400W and a maximum speed of 3000r / min; the servo motor driver is a Mitsubishi MR-J2S-40A servo driver; and the reducer is a Japanese Lixinbao VRSF-25C-14BB14 reducer with a reduction ratio of 1:25 and a backlash of 15 minutes.

[0083] The tapered roller bearing is model number 32004, with an outer diameter of 42mm, an inner diameter of 20mm, and a width of 15mm.

[0084] The charge amplifier selected is the YE5850 type charge amplifier from Jiangsu Lianeng Electronics Co., Ltd.; the piezoelectric amplifier circuit uses the APEX-PA241DW model piezoelectric amplifier, which has a magnification factor of up to 52 times and can amplify -5V to +5V to -260V to +260V.

[0085] 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 2.6Hz, with 4G of memory, and the motherboard has a PCI interface to install the motion control card.

[0086] 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 multi-flexible L-shaped beam based on flexible joints, characterized in that, It includes a flexible L-shaped beam body, a vibration section, a vibration detection section, and a vibration control section; The main body of the multi-flexible L-shaped beam includes an upper flexible joint. The lower end of the upper flexible joint is connected to the upper clamping frame. The upper clamping frame is equipped with four flexible beams. The four flexible beams are installed horizontally, facing four different directions: front, back, left, and right. Specifically, they include two downward-sloping convex L-shaped flexible beams and two downward-sloping concave L-shaped flexible beams. One end of each of the four flexible beams is connected to the upper clamping frame through a clamping plate, which is called the fixed end. The other end is the free end. It also includes a lower flexible joint, the upper end of which is connected to the upper clamping frame, and the lower end of which is connected to the lower clamping frame. The lower clamping frame is fixedly installed with four flexible beams. The four flexible beams are installed horizontally, facing four different directions: front, back, left, and right. Specifically, they include two upwardly inclined convex L-shaped flexible beams and two upwardly inclined concave L-shaped flexible beams. One end of each of the four flexible beams is connected to the lower clamping frame through a clamping plate, which is called the fixed end, and the other end is the free end. Tension springs are installed between adjacent flexible beams, and the free ends of the flexible beams extend into the water tank and are partially immersed in the liquid in the water tank; The vibration section includes a first servo motor vibration section and an underwater propeller vibration section. The first servo motor vibration section is used to drive the upper flexible joint to move, and further drive the flexible beam to rotate. The underwater propeller vibration section is used to drive the vibration of a portion of the flexible beam immersed in the liquid in the tank. The vibration detection section is used to detect the vibration signal of the flexible beam; The vibration control section is used to suppress the vibration of the flexible beam.

2. The vibration monitoring and control device for a multi-flexible L-shaped beam according to claim 1, characterized in that, The vibration part of the first servo motor includes a first servo motor and a first reducer. The bottom ends of the first servo motor and the first reducer are connected to each other, and the output shaft of the reducer is connected to the upper flexible joint.

3. The vibration monitoring and control device for a multi-flexible L-shaped beam according to claim 2, characterized in that, The upper and lower flexible joints have the same structure, including two torsion springs and a sleeve. The two torsion springs are set at the upper and lower ends of the reducer output shaft. One end of the torsion spring is connected to the reducer output shaft, and the other end is connected to the sleeve. The two torsion springs are installed in opposite directions. The sleeve and the reducer output shaft are connected to each other through the torsion springs and tapered roller bearings to form a flexible joint.

4. The vibration monitoring and control device for a multi-flexible L-shaped beam according to any one of claims 1-3, characterized in that, The underwater propeller vibration section includes a propeller, a reducer connection platform, a second reducer, a second servo motor, and a mounting bracket. The propeller is installed at the bottom of the water tank. The propeller is connected to the second reducer through the reducer connection platform, and the second servo motor is connected to the second reducer.

5. The vibration monitoring and control device for a multi-flexible L-shaped beam according to claim 4, characterized in that, The included angle between identical flexible beams is 180 degrees, and the included angle between adjacent flexible beams is 90 degrees.

6. The vibration monitoring and control device for a multi-flexible L-shaped beam according to claim 1, characterized in that, The vibration detection section includes a piezoelectric ceramic sensor, which is installed on the flexible beam. Each flexible beam has one piezoelectric ceramic sensor. The piezoelectric ceramic sensor detects the vibration signal, which is amplified by a charge amplifier and then input to a terminal board. The terminal board then inputs the signal to a motion control card. The A / D module in the motion control card converts the analog signal into a digital signal, which is finally input to the computer.

7. The vibration monitoring and control device for a multi-flexible L-shaped beam according to claim 6, characterized in that, The vibration control section includes a piezoelectric actuator. The computer calculates the control quantities corresponding to the first servo motor, the second servo motor, and the piezoelectric actuator based on the vibration detection signal, generates corresponding control signals, and drives the first servo motor, the second servo motor, and the piezoelectric actuator to suppress the vibration of the flexible beam.

8. The vibration monitoring and control device for a multi-flexible L-shaped beam according to claim 1, characterized in that, The propeller has eight blades, which are evenly distributed along a 360° circumference.

9. The vibration monitoring and control device for a multi-flexible L-shaped beam according to claim 7, characterized in that, The piezoelectric actuator comprises 32 pieces, with 4 pieces installed on each flexible beam, two pieces on each side, symmetrically installed and connected in parallel.

10. A method for measuring and controlling the vibration of a multi-flexible L-shaped beam according to any one of claims 1-9, characterized in that, Includes the following steps: Step 1: The first servo motor drives the excitation part to cause the flexible beam to vibrate; the underwater propeller vibration excitation part stirs the water in the tank in a specified direction, thereby causing the flexible beam submerged in the water to vibrate. Step 2: The vibration detection section inputs the vibration signal of the flexible beam into the computer; Step 3: The computer receives the vibration signal and processes it. After running the control algorithm, it calculates the control quantities corresponding to the first and second servo motors and piezoelectric actuators, and generates corresponding control signals to further suppress the vibration of the flexible beam. Step 4: By changing the control parameters of the control algorithm, repeated experiments are conducted to obtain multiple experimental results.

Images