Parameter intelligent adjustable inertial mass damper and control method thereof

Abstract

The application discloses a parameter intelligent adjustable inertial mass damper and a control method thereof, which are applied to efficient vibration control of super-long stay cables on large-span cable-stayed bridges in the field of civil engineering, and the damper is composed of an inertial mass element, a damping element, a self-power supply system and a heat dissipation system.The inertial mass element is combined with a conductor disc and a linear module through a ball screw, and the continuous adjustment of the equivalent inertial mass is realized by using a stepping motor to control the position of a sliding block; the damping element adopts an electric eddy current structure, a damping force is generated by cutting the magnetic field of a permanent magnet and an electromagnet by a rotating conductor disc, and the real-time regulation and control of the damping force are realized by adjusting the current of the electromagnet.The application realizes the real-time calculation and self-adaptive adjustment of optimal and suboptimal control parameters of a target mode by combining acceleration spectrum analysis and an optimization algorithm, and has the advantages of high power, high efficiency, compact structure, intelligent control, self-power supply and strong durability, and the vibration reduction effect of the stay cable is significantly improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of vibration control, and particularly relates to a parameter-intelligently-adjustable inertial mass damper and a control method thereof. BACKGROUND

[0002] With the rapid development of China's transportation industry, more and more long-span bridge structures are put into operation and use with the development of building materials and construction technology. Among them, cable-stayed bridges are widely used in long-span bridge construction due to their strong spanning capacity, beautiful appearance and good economy. As one of the important force members of cable-stayed bridges, the cable has the advantages of small self-weight, flexible arrangement, convenient construction and beautiful appearance. However, due to its large flexibility and small self-damping, it is easily affected by environmental excitation and vibrates. Large cable vibration may cause structural fatigue, damage to cable anchorage, induce cable corrosion and even bridge collapse, and affect the normal use of the bridge. Installing an external viscous damper is the most widely used cable vibration reduction scheme in engineering practice, but its maximum modal damping ratio is low and its damping effect is limited by the installation position, making it increasingly unable to meet the effective damping demand of the cable on the current and under-construction long-span cable-stayed bridge. In the process of research and exploration of high-efficiency dampers, inertial mass dampers with negative stiffness characteristics have been proven to be able to generate a large equivalent inertial mass through physical mechanisms such as ball screws and can provide a modal damping ratio up to 10 times that of traditional viscous dampers.

[0003] However, in the field of cable vibration reduction, the optimization design and experimental research of inertial mass dampers found that the optimal parameter values of each order that can make the cable-damper system obtain the highest modal damping ratio are quite different. Therefore, if the traditional passive damper design method commonly used at present is used, i.e., the damper parameters are set in advance for a low-order mode, the inertial mass damper cannot achieve the expected cable vibration control effect when the main vibration mode of the cable is not the pre-designed optimal mode in actual engineering application, and even lower than the traditional passive viscous damper. In recent years, intelligent dampers combined with semi-active intelligent control technology have been continuously proposed and used, which provide a new idea for cable vibration control by real-time feedback adjustment of damper parameters. Therefore, how to design and develop inertial mass and damping components with fast parameter self-adaptive adjustment, strong practicality, high output efficiency and good durability, and compact overall intelligent inertial mass damper; how to better utilize the health monitoring data of long-span bridge structures to design damper optimization control strategies and more effectively control the single-mode and multi-mode large amplitude vibration of super-long cables in engineering practice to ensure the safe service of cable-stayed bridges and cables are the current social focus and the research focus in bridge design.

[0004] Currently, some research teams have made the following attempts: the Chinese patent technology with publication number CN111576214B uses a ball screw as a motion conversion device, changes the rotational speed of the rotating mass by changing the current using the electromagnetic clutch principle, thereby changing the inertial mass. The Chinese patent application with publication number CN118793314A uses a ball screw rod to drive the nut to rotate, the nut is installed with a small ball connected to a sliding resistor and a conductor plate, the resistance is changed by the centrifugal force to change the current to generate variable eddy current damping force. The above-mentioned patent technologies only change the inertial mass or the damping coefficient, and cannot achieve the optimal design parameters of the inertial mass damper, and the damping force is limited. Therefore, the Chinese patent application with publication number CN119571938A uses the translation of the ball screw piston rod to rotate the screw shaft, the piston rod is connected to the nut, the mechanical properties of the magnetorheological fluid in the magnetorheological cavity are controlled by the current to change the damping coefficient, and the position of the slider on the rotating disc is controlled by the actuator to change the inertial mass, thereby realizing the simultaneous adjustment of the inertial mass and the damping coefficient; but the theoretical model of this type of damper is relatively complex, the actuator control parameter and the nonlinear calibration relationship between the damper physical and theoretical parameters are adjusted by the claw type rotating arm to adjust the position of the slider on the rotating disc; the damping element in the patent technology uses a magnetorheological damper, and the MR (magnetorheological) liquid needs to be adjusted to realize variable damping, and the mechanical model of the MR liquid is highly nonlinear, which is neither a linear viscous coefficient nor a stiffness effect, making it difficult to achieve efficient adjustment; moreover, for a specific type of MR liquid, the adjustable range of the equivalent viscous coefficient is limited, which cannot meet the requirements of continuous adjustment of the viscous coefficient and wide adjustment range; at the same time, the overall structure design is relatively long in the length direction, occupies a large space, and the structure is not compact, which limits the application of actual engineering structures. In addition, there are few invention design methods for cable multi-modal control dampers, such as the Chinese patent technology with publication number CN115387218B, which provides a cable multi-modal control adaptive damper and a parameter optimization method thereof. This design requires multiple element optimization to achieve multi-modal control, resulting in a large number of required optimization parameters, and the acquisition of optimal damping coefficients for each modal does not consider the mutual influence between elements, and the damping parameter obtained by only optimizing the multi-modal may not provide sufficient modal damping ratio when the cable experiences single-modal large amplitude vibration, limiting the vibration control effect.

[0005] Therefore, it is particularly important to develop an intelligent damper and a control method thereof which can adaptively adjust the damping parameters based on the real-time vibration characteristics (single-modal or multi-modal main vibration) of the cable, have fast response speed, compact structure, large output, and high output efficiency, to meet the cable vibration reduction requirements of large-span cable-stayed bridges in actual engineering. SUMMARY

[0006] In view of the above, the present application provides a parameter intelligent adjustable inertial mass damper and a control method thereof, which can provide a cable with a modal damping ratio several times that of a traditional viscous damper in actual engineering applications, and can also control damper parameters in real time according to cable vibration acceleration monitoring data, in combination with a single-mode optimal and multi-mode suboptimal damper parameter control algorithm, to achieve effective control of cable vibration, and has the characteristics of fast parameter self-adaptive adjustment, high output efficiency and good durability.

[0007] A parameter intelligent adjustable inertial mass damper, comprising a control system and an upper connecting frame and a lower connecting frame connected in the axial direction of the damper, wherein the upper connecting frame is connected to a bridge deck through a connecting piece, and the lower connecting frame contains an inertial mass element and a damping element.

[0008] The inertial mass element comprises a ball screw, a ball nut and a conductor disc, the ball screw penetrates the lower connecting frame, one end of the ball screw is deep into the upper connecting frame, and the other end of the ball screw is connected to the cable through a connecting piece; the ball nut is installed on the ball screw through a bearing; the conductor disc is fixed on the bottom of the ball nut through bolts; when the cable vibrates, the ball screw is driven to rotate, and the ball nut is also driven to rotate, and then the conductor disc is driven to rotate; four linear modules are installed on the conductor disc, and the linear modules are distributed in a cross-symmetric manner around the ball screw; each linear module comprises a guide rail, a sliding block and a stepping motor; during cable vibration, an acceleration sensor installed on the cable is used to collect vibration acceleration signals; the control system drives the stepping motor to control the sliding block to slide on the guide rail according to the collected vibration acceleration signals, and the rotation radius of the sliding block is adjusted to control the equivalent inertia mass of the damper.

[0009] The damping element is designed in an eddy current type, comprising two electromagnets and two permanent magnets, the electromagnets and the permanent magnets are installed on the inner side of the bottom plate of the lower connecting frame and are distributed in a cross-symmetric manner around the ball screw, the conductor disc is used to cut the magnetic induction lines generated by the permanent magnets and the electromagnets to generate eddy current damping force; the coil current of the electromagnet is controlled by the control system. The conductor disc can be used as a rotating inertia element of the inertial mass part and a conductor member for cutting the magnetic induction lines to generate eddy current damping force of the eddy current damping part, so that the structure of the damper is more compact.

[0010] Further, the conductor disc is made of a high-conductivity material (such as copper, aluminum, etc.), and the bottom of the electromagnet and the permanent magnet is provided with a back iron plate to ensure the closure of the magnetic field, reduce the magnetic flux leakage, and improve the magnetic flux density.

[0011] Further, a nylon sleeve is arranged at the upper and lower openings of the lower connecting frame through which the ball screw penetrates, which can not only play a force transmission role, but also play a buffering role to reduce the collision loss of the damper during work.

[0012] Further, the ball screw is provided with an electromagnetic slip ring to ensure that the wires between the stepper motor and the control system are not entangled when the inertial element rotates.

[0013] Further, the lower connecting frame further comprises a self-powered system, which is composed of two electromagnetic generators installed on the conductor disc. The electromagnetic generator comprises a plurality of permanent magnets and an electromagnetic coil wound around the core sleeve. In the daily vibration environment, the plurality of permanent magnets are driven by the conductor disc to rotate outside the electromagnetic coil to realize the electromagnetic generation of the outer rotor, so as to convert mechanical energy into electrical energy and collect energy. In the case of insufficient or damaged external power supply caused by extreme weather and extreme load, the electromagnetic generator supplies power to the control system by using the stored electrical energy.

[0014] Further, the lower connecting frame further comprises a heat dissipation system, which comprises heat dissipation fins welded to the back of the conductor disc, heat conductive copper columns arranged on the surface of the electromagnet shell, heat dissipation holes on the conductor disc, symmetrical holes on the lower connecting frame shell, heat conductive sheets arranged on the outside of the lower connecting frame bottom plate, and heat conductive gel. The heat dissipation system can effectively suppress the eddy current heating of the conductor disc and the heating problem of the electromagnetic coil caused by long-time power supply.

[0015] Further, the control system integrates a composite optimization control algorithm of the damper parameter single-mode optimal and multi-mode suboptimal by code, and a mathematical relationship between the damper theoretical optimization parameters (inertial mass coefficient and damping coefficient), physical parameters (slider position and magnetic field size generated by the electromagnet), and control parameters (step motor input current and electromagnet coil current) calibrated in the laboratory. The control system realizes real-time adjustment of the damper inertial mass coefficient and damping coefficient by controlling the step motor and the electromagnet coil current.

[0016] Further, the control system comprises an information interaction device. The control parameters of the damper, the inertial mass coefficient, the damping coefficient, and the vibration acceleration signal and its frequency spectrum of the cable are transmitted to the upper computer for display, so that the user can view them.

[0017] The control method of the above-mentioned parameter-intelligently-adjustable inertial damper comprises the following steps:

[0018] (1) Determine the design parameters of the cable and the damper according to the vibration reduction requirements of the engineering project, including the design value of the cable force, the length of the cable, the arrangement position of the damper, and the vibration modal order of the cable to be controlled;

[0019] (2) Set the value interval of the damper parameters (i.e. the inertial mass coefficient and the damping coefficient), and calculate the damper parameters corresponding to each vibration modal order using the state space model of the cable-inertial damper, which are used as the damper optimization parameters of the single-mode control target;

[0020] (3) Similarly based on the cable-iner state space model, a plurality of groups of graphs (each group corresponds to a different value of the iner coefficient, and the iner coefficient value interval is related) are drawn within the range of values of the damper parameters, and each group of graphs shows the change of the damping ratio of each order vibration mode of the cable with the damping coefficient of the damper; for any graph, find the minimum value of the damping ratio of each order vibration mode at different damping coefficients and connect them into a curve, and further determine the maximum value point of the damping ratio and its corresponding damping coefficient on the minimum value curve;

[0021] (4) Find the global maximum value point from all the maximum value points of the graphs, and take the iner coefficient corresponding to the graph of the point and the damping coefficient corresponding to the point as the optimized parameters of the damper of the multi-modal control target;

[0022] (5) Calibrate the mathematical relationship between the theoretical optimized parameters, physical parameters and control parameters of the damper in the laboratory and embed it into the control system in the form of code writing;

[0023] (6) When the cable vibrates, the damper starts to work, and the initial state adopts the optimized parameters of the damper corresponding to the first order vibration mode of the cable, and at the same time the control system starts to acquire and process the vibration acceleration signal for vibration mode identification;

[0024] (7) When the cable vibrates abnormally, the vibration acceleration signal is subjected to fast Fourier transform to obtain the frequency spectrum information of the signal, and the control system classifies and identifies whether the single mode or the multi-modal vibration is dominant according to the frequency spectrum information, so as to adopt the optimized parameters of the damper corresponding to the control target, and calculate the control parameters according to the mathematical relationship calibrated in the laboratory to control the damper in real time.

[0025] Based on the above technical scheme, the iner and damping components in the damper are compact in structure, and are a damper combination with strong practical performance, which provides a practical and efficient external damper vibration reduction scheme for long-term vibration reduction of long-span cable-stayed bridge cables (especially super-long cables). Therefore, the creativity and beneficial technical effects of the present application mainly lie in the following aspects:

[0026] 1. The present application is applied to the field of vibration control of cables, and can provide a modal damping ratio several times that of a traditional viscous damper; compared with the prior art passive iner damper design or the single-parameter variable design in some iner dampers at present, the present application can provide more stable and efficient vibration reduction effect for cable vibration in actual engineering.

[0027] 2. The invention can provide a large equivalent inertia mass, while the damping element is designed as a large-tonnage eddy current damper, the overall combined damper structure is compact, high output and high output efficiency; in addition, the outstanding damping performance of the invention has been verified by experiments, so it is more suitable for damping control of long-span cable-stayed bridge cables in practical engineering.

[0028] 3. The invention is a single-mode optimal and multi-mode suboptimal optimization algorithm designed for the theoretical and experimental study of the cable-inertia mass damper system, which further calculates the theoretical optimization parameters, physical parameters and control parameters of the intelligent damper, calibrates them in the laboratory, uses the calibration curve to write the control algorithm and write it into the intelligent control system to realize the intelligent regulation and control of the damper parameters in practical applications; in addition, the control algorithm can still update and iterate the calibration parameters in practical applications, has strong autonomy, and is suitable for different engineering needs.

[0029] 4. The invention is based on the intelligent control system design to complete the real-time regulation and control of the damper based on the cable vibration signal, and the control principle is clear and explicit, and the realization is strong. The stepping motor control and electromagnetic input current control technology are mature and reliable; at the same time, compared with other types of adjustable dampers (such as magnetorheological dampers), the damper in the invention has continuous adjustable double parameters, a large adjustment range and high cost performance.

[0030] 5. The invention considers the problem that the semi-active control damper is easy to fail due to external power supply damage in practical engineering applications, especially in extreme weather conditions, in the overall design of the structure, the electromagnetic power generation is realized by reasonably using the rotating assembly, the vibration energy can be absorbed to store electric energy under normal vibration conditions, and the self-power supply system design can maintain the normal use of the damper control system when the external power supply fails, thereby ensuring the stable and efficient damping performance of the damper.

[0031] 6. The invention uses a combination of permanent magnets and electromagnets in the design of the damping element, which ensures that the damper will not completely lose its working ability even in the state of external power cut-off and self-power supply system energy depletion, while increasing the adjustable range of damping parameters. In addition, in view of the problem of heating caused by eddy current and electromagnetic coil caused by long-time power supply in the conductor disc of the eddy current damper, multiple heat dissipation designs including heat dissipation fins, symmetrical air holes, heat conduction copper columns and heat conduction gels are made, so that the invention always maintains high damping performance and high durability in continuous work. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 It is the overall structure diagram of the intelligent inertia damper of the invention.

[0033] Figure 2 Top view of the arrangement of the conductor disc and the linear module.

[0034] Figure 3 Arrangement diagram of the inside of the lower connecting frame bottom plate.

[0035] Figure 4 Arrangement diagram of the outside of the lower connecting frame bottom plate.

[0036] Figure 5 Wiring elevation view of the outer edge of the lower connecting frame.

[0037] Figure 6 Graph of the change of the target modal damping ratio of each order with the damping coefficient under a specific inertial mass.

[0038] Figure 7 Graph of the change of the target modal damping ratio of each order with the inertial mass under a specific damping coefficient.

[0039] Figure 8 Application flowchart of the intelligent inertial mass damper in the embodiment of the application.

[0040] Figure 9 Flowchart of the composite optimal control algorithm of the single modal optimization and the multi-modal suboptimization.

[0041] Figure 10 Time history signal diagram of the input control displacement of the loading machine and the output of the intelligent damper under the working condition 1 of the verification example of the application.

[0042] Figure 11 Hysteresis curve result diagram of the performance test of the intelligent damper under the working condition 1 of the verification example of the application.

[0043] Figure 12 Time history signal diagram of the input control displacement of the loading machine and the output of the intelligent damper under the working condition 2 of the verification example of the application.

[0044] Figure 13 Hysteresis curve result diagram of the performance test of the intelligent damper under the working condition 2 of the verification example of the application.

[0045] In the figure: 1 - first connecting part, 2 - second connecting part, 3 - upper connecting frame, 4 - lower connecting frame, 5 - ball screw, 6 - back iron plate, 7 - electromagnet, 8 - heat-conducting copper column, 9 - permanent magnet, 10 - heat dissipation fin, 11 - conductor disc, 12 - linear module, 12-1 - sliding block, 12-2 - guide rail, 12-3 - stepping motor, 13 - electromagnetic generator, 14 - bolt, 15 - electromagnetic slip ring, 16 - upper nylon sleeve, 17 - ball nut, 18 - gasket and ball bearing, 19 - lower nylon sleeve, 20 - heat-conducting fin and heat-conducting gel, 21 - acceleration sensor, 22 - wire groove and wire, 23 - heat dissipation hole, 24 - cable. DETAILED DESCRIPTION

[0046] To describe the present application more specifically, the technical solutions of the present application are described in detail below in combination with the drawings and specific embodiments.

[0047] In the preparation stage, the present application determines the design parameters of the cable to which the damper is arranged according to the vibration reduction requirements of the engineering project, including the design value of the cable force, the length of the cable and the arrangement position of the damper, etc. In the design stage, according to the cable parameters and installation position determined in the preparation stage, by setting the damper parameter value interval of the inertia mass and damping parameter, the damper single-mode optimal parameters corresponding to each order vibration mode of the cable are calculated according to the cable-inertia mass damper state space model (see the literature [Duan F, Deng N, Rao Y. Spectrum analysis of catenary cable with optimal viscous-inertia mass damper under random wind based on generalized state space formula. International Journal of Structural Stability and Dynamics 2024.]) For multi-modal control suboptimal parameter selection, also based on the state space model, a plurality of groups of curve graphs (each group corresponds to a different inertia mass value, related to the inertia mass parameter interval) are drawn within the damper parameter value interval, as shown in Figure 6 Each group of curve graphs shows the change of the damping ratio of each target order mode with the damping coefficient. For each curve graph, the following work is done: (1) find the minimum value of the damping ratio of each target mode under different damping coefficients, and connect them into a curve (i.e. the red star dotted line in Figure 6 ); (2) on the minimum value curve, further determine the maximum value point of the damping ratio and its corresponding damping coefficient (the intersection point in Figure 6 is the maximum value point of the damping ratio of the first four order modes under the current inertia mass coefficient), and then find the global maximum value point in each maximum value point in a plurality of curve graphs (related to the inertia mass parameter value interval). The inertia mass value corresponding to the curve graph of the point and the damping coefficient value corresponding to the point are the optimal parameter values of the damper corresponding to the set multi-modal control target.

[0048] Figure 7 Each group of curves in Figure 6 shows the change of the damping ratio of each target order mode with the inertia mass. For each curve graph, the same work as Figure 7 is done.The minimum value of the damping ratio of the first four target modes under different inertial mass coefficients is connected by a middle red star dashed line, and the intersection is the maximum point of the damping ratio of the first four modes under the current damping coefficient; meanwhile, the relationship between the theoretically optimized parameters (inertial mass coefficient and damping coefficient) of the damper, the physical parameters (slider position and the size of the magnetic field generated by the electromagnet) and the control parameters (step motor input current and electromagnet coil current) is calibrated in the laboratory and embedded in the step motor controller of the inertial mass element and the current controller of the electromagnet in the damping element to realize real-time regulation and control of the double parameters of the intelligent damper in the actual engineering process. During actual use, the characteristic relationship curve calibrated in the laboratory may deviate from the actual output, which can be updated and corrected regularly during actual use to ensure the reliability and efficiency of the damper control performance.

[0049] In the working phase, the designed intelligent damper is installed at the corresponding position of the cable 24, as shown in Figure 1 The first connecting part 1 is connected with the cable 24, and the second connecting part 2 is connected with the bridge deck. The intelligent damper proposed in the present application mainly has two parts of inertial mass element and damping element. When the cable 24 vibrates, it drives the ball screw 5 to move horizontally and converts the horizontal movement into the rotation of the ball nut 17. The ball nut 17 and the conductor disc 11 are fixedly connected by bolts. The conductor disc 11 is made of high-conductivity materials such as copper and aluminum and can rotate with the ball nut 17. As shown in Figure 2 Four cross-symmetric linear modules 12 are fixed on the conductor disc 11 connected to the ball nut 17. Each linear module 12 is composed of a slider 12-1, a guide rail 12-2 and a step motor 12-3. In the initial state, the slider 12-1 is at the root of the linear module 12, at which time the inertial mass is the smallest. During the rotation of the conductor disc 11 and the linear module 12 with the ball nut 17, the step motor 12-3 can be controlled by the controller according to the collected cable 24 vibration acceleration signal and using a preset optimization control algorithm to realize the position change of the slider 12-1 on the linear guide rail 12-2, so as to realize the regulation and control of the equivalent inertial mass through the adjustment of the rotating radius of the slider.

[0050] Meanwhile, the damping element is designed based on the principle of eddy current damper. The eddy current damping part is composed of an electromagnet 7, a permanent magnet 9, a back iron plate 6 and a conductor disc 11. The conductor disc 11 can serve as both a rotating inertia element of the inertial mass part and a conductor member for generating eddy current damping force by rotating to cut the magnetic induction lines, so that the structure of the entire damper is more compact. As shown in Figure 3As shown, the intelligent damper of this invention arranges two electromagnets 7 and two permanent magnets 9 in a cross-shaped, symmetrical arrangement on the base plate of the lower connecting frame 4. The iron core in the electromagnet magnetic field source is made of soft iron material with high magnetic permeability. A back iron plate 6 is provided below the magnet to ensure magnetic field closure, reduce magnetic leakage, and increase magnetic flux density. The vibration of the cable 24 drives the ball screw 5 to translate, which is then converted into the rotation of the ball nut 17 and the conductor disk 11. As the conductor disk 11 rotates, it cuts the magnetic field lines generated by the permanent magnets 9 and electromagnets 7, generating eddy current damping force.

[0051] To ensure reliable force transmission of the damper, such as Figure 1 As shown, the damper design uses an upper connecting frame 3 and a lower connecting frame 4 to transmit inertial force and damping force. Meanwhile, a washer and ball bearing 18 are installed along the ball screw axis on the lower connecting frame to vertically limit the ball nut 17, ensuring the conductor disk can only rotate. Upper nylon sleeves 16 and lower nylon sleeves 19 are installed at the openings of the upper and lower plates of the lower connecting frame 4, serving both force transmission and buffering functions to reduce collision losses during operation. Furthermore, to ensure smooth force transmission between the upper and lower connecting frames, the connecting plates must have sufficient thickness, and multiple bolts 14 can be used for connection.

[0052] This invention's intelligent damper enables adaptive control of different vibration modes during the vibration control of cable 24. The damper features an integrated structure: for both the inertial mass element and the damping element, a composite optimization control algorithm for single-mode optimal and multi-mode suboptimal damper parameters is designed; both the motor of the inertial mass element and the electromagnet 7 of the damping element are equipped with sensors capable of receiving and processing vibration acceleration data of cable 24 from the health monitoring system. This acceleration data can be obtained from the accelerometer 21 or other monitoring tools. Simultaneously, a pre-programmed optimized control algorithm and calibration relationship (i.e., matching the equivalent theoretical parameters of the damper, the physical parameters of the damper, and the control parameters of the controller are completed in the laboratory) are embedded in the controller to facilitate real-time adjustment of the damper's dual parameters. Since the linear module 12 requires connecting wires, an electromagnetic slip ring 15 is specifically configured to prevent the wires from tangling during rotation of the inertial mass component; the wires of the inertial mass element and the damping element are arranged in the wire groove 22 along the outer edge of the lower connecting frame, such as... Figure 4 As shown.

[0053] Meanwhile, in order to ensure that the intelligent damper setting can be more suitable for the engineering practical application of the long-span cable-stayed bridge, a self-powered system is designed, which is composed of an electromagnetic generator 13 installed on the conductor disc 11, including a plurality of permanent magnets, an electromagnetic coil wound around the core sleeve, and is used to collect energy in the daily vibration environment. In the case of daily small amplitude vibration, the electromagnetic generator 13 in the self-powered system is in a charging state, and in the case of extreme weather and extreme load leading to insufficient or damaged external power supply, the stored energy can be used for power supply of the controller of the inertial mass and the damping element.

[0054] On the other hand, since the eddy current damper part generates a large amount of heat during operation, in order to solve the problem of heat generation of the conductor disc 11 due to eddy current and heat generation of the electromagnetic coil resistance temperature rise in the eddy current damper, an integrated heat dissipation structure system is designed, which includes an aluminum heat dissipation fin 10 welded on the back of the conductor disc 11, a heat-conducting copper column 8 on the surface of the electromagnet 7 shell, a heat dissipation hole 23 on the frame shell above the conductor disc 11 and the electromagnet 7 and the permanent magnet 9, and a heat-conducting sheet and heat-conducting gel 20 (as shown in Figure 5 When the intelligent damper works, the eddy current damper part generates a large amount of heat under the effect of eddy current, and the aluminum heat dissipation fin 10 fixed on the back of the conductor disc 11 also rotates, and the fan blades are driven to rotate and dissipate heat by the airflow; at the same time, the heat-conducting copper column 8 can efficiently transfer the heat generated by the electromagnet 7 through the fan blades to be discharged through the air hole 23.

[0055] In the actual application process, the intelligent inertial mass damper further includes an information interaction device, and the controller can transmit the control physical parameters (current input) and equivalent theoretical parameters (inertial mass and damping coefficient) of the damper, as well as the vibration acceleration and frequency spectrum information of the cable 24 to the upper computer for display, so as to be viewed by the user.

[0056] Embodiment

[0057] The embodiment provides a parameter-intelligent-adjustable inertial mass damper and a control method thereof, which is suitable for single-mode and multi-mode vibration control of an ultra-long cable, and has stable and significant damping effect, and the specific implementation and process are as shown in Figure 8

[0058] Firstly, the target cable parameters of the intelligent damper to be arranged are determined according to the vibration reduction demand of the engineering project, including the design value of the cable force, the length of the cable and the arrangement position of the damper; then, according to the determined cable parameters and the installation position of the damper, the application is as shown in Figure 9 ​The single-mode optimal multi-mode sub-optimal damper parameter optimization control algorithm determines the damper size and motor model, calibrates the relationship between the theoretical optimization parameters (inertia mass coefficient and damping coefficient) of the damper, the physical parameters (slider position and the magnetic field generated by the electromagnet) and the control parameters (step motor input current and electromagnet coil current) in the laboratory and embeds the algorithm into the step motor controller of the inertia mass element and the current controller of the electromagnet in the damping element to realize the real-time regulation and control of the double parameters of the intelligent damper in the actual engineering work process.

[0059] After the above steps are completed, the damper is installed at the corresponding position of the cable 24, as shown in the figure. Figure 1 As shown, the first connecting part 1 is connected with the cable 24, and the second connecting part 2 is connected with the bridge deck. When initially installed, the parameters of the damper are the optimal parameters for controlling a certain pre-designed low-order vibration mode of the cable 24, at this time the slider 12-1 on the linear module 12 of the inertia mass part is located at the root of the module; when the cable 24 vibrates, its vibration will be converted into the translation of the ball screw lever 5, and then converted into the rotation of the ball nut 17, the conductor disc 11 and the linear module 12 fixed thereon, thereby generating a huge equivalent inertia mass; at the same time, the rotation of the conductor disc 11 will cut the magnetic induction lines generated by the electromagnet 7 and the permanent magnet 9 fixed on the bottom plate of the lower connecting frame, thereby generating an eddy current damping force on the conductor disc 11, and the resultant force of the inertia force and the eddy current damping force is the final output of the damper.

[0060] In order to ensure the reliable transmission of force of the damper, the upper connecting frame 3 and the lower connecting frame 4 are designed to transmit the inertia mass and damping force, and at the same time, the gasket and the ball bearing 18 are arranged on the lower connecting frame 4 to complete the vertical limiting of the ball nut 17, and the upper nylon sleeve 16 and the lower nylon sleeve 19 are arranged at the opening of the upper and lower plates of the lower connecting frame 4, which can not only play a role in transmitting force, but also reduce the collision loss of the damper during work. At the same time, in order to ensure the force transmission effect of the upper and lower connecting frames, the thickness of the connecting plate is sufficient and at the same time multiple bolts 14 are used for connection.

[0061] Under the condition of daily small amplitude, the rotation of the conductor disc 11 caused by vibration will charge the electromagnet generator 13 fixed thereon and store electric energy, and when the external power supply fails, the self-powered system can maintain the normal use of the damper controller, thereby ensuring the high-efficiency and stable damping performance of the damper.

[0062] When the bridge cable 24 occurs non-prescribed single mode or multi-mode large amplitude vibration, the acceleration sensor 21 on the cable 24 measures the acceleration signal, and the frequency spectrum information of the time history data is obtained by performing fast Fourier transform (FFT) on the measured acceleration time history signal. After the controller algorithm of the inertial mass and damping element automatically identifies and classifies the information as a single mode or multi-mode dominant vibration condition, the control signal containing the target control information is transmitted to the linear module 12 and the damping element respectively, and the parameter adaptive adjustment is completed. At this time, the slider 12-1 in the linear module 12 will move to the corresponding position according to the set program, realizing the real-time change of the inertial mass in the working process; at the same time, the current in the coil of the electromagnet 7 will also change accordingly to achieve the single mode optimal or multi-mode suboptimal control parameter, so as to form a closed loop control and realize the real-time control of the abnormal large amplitude vibration of the cable 24.

[0063] Since a large amount of heat is generated in the process of large amplitude cable vibration control, in order to prevent the damping element from affecting its performance and service life due to overheating, the embodiment is provided with a heat dissipation system, which includes an aluminum heat dissipation fin 10 welded on the back of the conductor disc 11, a heat conductive copper column 8 on the surface of the electromagnet 7 shell, a heat dissipation air hole 23 on the frame shell, and a heat conductive sheet and heat conductive gel 20 arranged below the electromagnet 7 and the permanent magnet 9. When the intelligent damper works, a large amount of heat is generated in the eddy current damping part under the effect of eddy current effect, and the aluminum heat dissipation fin 10 fixed on the back of the conductor disc 11 also rotates, and the fan blades are driven by the airflow to start rotating and dissipating heat; at the same time, the heat conductive copper column 8 can efficiently transfer the heat generated by the electromagnet 7 through the fan blades to the air hole 23 to achieve the effect of heat dissipation.

[0064] Verification example

[0065] In order to verify that the parameter intelligent adjustable inertial mass damper and its control method of the present application can effectively continuously regulate and control the damper parameters, we designed and manufactured a damper prototype in the laboratory. Since the damping element, i.e. the eddy current damper technology, is relatively mature, and its reliable regulation and control of damping force have been widely recognized by technicians in this technical field, therefore the verification example prototype only contains the adaptive inertial mass element. After the host computer sets the loading displacement instruction, the lower end of the fatigue testing machine moves according to the pre-set loading displacement, and the pre-set force sensor on the upper end of the fatigue testing machine collects the output signal of the inertial mass element. During the loading process, the frequency of the loading machine increases from small to large; at the same time, the optimized control algorithm pre-written in the intelligent controller will adjust the slider position in real time with the change of the loading frequency, so as to regulate and control the equivalent inertia mass. Two test conditions are designed for this purpose:

[0066] Working condition 1: under the action of a sine displacement excitation with an amplitude of 1mm and a frequency varying from 0.5Hz to 1Hz, the slider position is adjusted from the root to the middle by the corresponding inertia element prototype controller.

[0067] Working condition 2: under the action of a sine displacement excitation with an amplitude of 1mm and a frequency varying from 0.5Hz to 1Hz and 1.5Hz, the slider position is adjusted from the root to the middle and the end by the corresponding inertia element prototype controller.

[0068] Figure 10 and Figure 11 The loading machine input control displacement and the output time history signal of the intelligent damper and the corresponding intelligent damper performance test hysteresis curve results under working condition 1 are given; Figure 12 and Figure 13 The loading machine input control displacement and the output time history signal of the intelligent damper and the corresponding intelligent damper performance test hysteresis curve results under working condition 2 are given.

[0069] As can be seen from the results of the two working conditions shown in the figures, the intelligent inertia damper and the control algorithm thereof can effectively adjust the slider position in real time according to the change of the vibration characteristics, so that the adaptive inertia element can accurately adjust the equivalent inertia mass, and the reliability and practicability of the present application are verified.

[0070] The above description of the embodiments is for facilitating the understanding and application of the present application by those skilled in the art, and those skilled in the art can easily make various modifications to the above embodiments, and apply the general principles described herein to other embodiments without creative labor. Therefore, the present application is not limited to the above embodiments, and the improvements and modifications of the present application made by those skilled in the art according to the disclosure of the present application should be within the protection scope of the present application.

Claims

1. A mass-inertial damper with intelligently adjustable parameters, characterized in that, It includes a control system and an upper connecting frame and a lower connecting frame connected along the axial direction of the damper. The upper connecting frame is connected to the bridge deck via a connector, and the lower connecting frame contains an inertial mass element and a damping element. The inertial mass element includes a ball screw, a ball nut, and a conductor disk. The ball screw passes through the lower connecting frame, with one end extending into the upper connecting frame and the other end connected to the cable via a connector. The ball nut is mounted on the ball screw via a bearing, and the conductor disk is fixed to the bottom of the ball nut with bolts. When the cable vibrates, it drives the ball screw, which in turn rotates the ball nut, thereby driving the conductor disk to rotate. Four linear modules are mounted on the conductor disk, arranged in a cross-shaped symmetrical pattern around the ball screw. Each linear module includes a guide rail, a slider, and a stepper motor. During cable vibration, an accelerometer mounted on the cable collects vibration acceleration signals. The control system uses a control algorithm based on the collected vibration acceleration signals to drive the stepper motor to control the slider to slide on the guide rail. The equivalent inertial mass of the damper is adjusted by regulating the rotation radius of the slider. The damping element adopts an eddy current design, including two electromagnets and two permanent magnets. The electromagnets and permanent magnets are installed on the inner side of the bottom plate of the lower connecting frame and are symmetrically distributed in a cross shape with the ball screw as the axis. The eddy current damping force is generated by the rotation of the conductor disk cutting the magnetic field lines generated by the permanent magnets and electromagnets. The coil current of the electromagnet is controlled by the control system. The lower connecting frame also includes a self-powered system, which consists of two electromagnetic generators mounted on a conductor disk. Each electromagnetic generator includes a multi-stage permanent magnet and an electromagnetic coil wound with an iron core sleeve. Under normal vibration conditions, the conductor disk drives the multi-stage permanent magnet to rotate outside the electromagnetic coil, thereby realizing external rotor electromagnetic power generation, converting mechanical energy into electrical energy and collecting energy. In the event of insufficient or damaged external power supply due to extreme weather or extreme loads, the electromagnetic generator will use the stored electrical energy to power the control system. The control system integrates a composite optimization control algorithm for single-mode optimal and multi-mode suboptimal damper parameters, as well as mathematical relationships between theoretical optimization parameters, physical parameters, and control parameters of the damper, calibrated in the laboratory. It achieves real-time adjustment of the damper's mass inertia coefficient and damping coefficient by controlling the stepper motor and the current of the electromagnet coil.

2. The intelligently adjustable inertial-mass damper according to claim 1, characterized in that: The conductor disk is made of a high conductivity material, and the electromagnet and permanent magnet are provided with a back iron plate at the bottom.

3. The intelligently adjustable inertial-mass damper according to claim 1, characterized in that: The lower connecting frame has nylon sleeves at the upper and lower openings through which the ball screw passes.

4. The intelligently adjustable inertial-mass damper according to claim 1, characterized in that: The ball screw is equipped with an electromagnetic slip ring.

5. The intelligently adjustable inertial-mass damper according to claim 1, characterized in that: The lower connecting frame also includes a heat dissipation system, which includes heat dissipation fins welded to the back of the conductor disk, heat-conducting copper pillars disposed on the surface of the electromagnet housing, heat dissipation vents on the conductor disk, symmetrical vents on the lower connecting frame housing, heat-conducting sheets and thermal conductive gel disposed on the outer side of the bottom plate of the lower connecting frame.

6. The intelligently adjustable inertial-mass damper according to claim 1, characterized in that: The control system includes an information interaction device, which transmits the control parameters of the damper, the mass coefficient, the damping coefficient, and the vibration acceleration signal and spectrum of the cable to the host computer for display by the user.

7. A control method for an intelligently adjustable inertial mass damper as described in any one of claims 1 to 6, comprising the following steps: (1) Determine the relevant design parameters of cables and dampers according to the vibration reduction requirements of the project, including cable force design value, cable length, damper arrangement position and the order of cable vibration mode to be controlled; (2) Set the value interval of the damper parameters, and use the state space model of the cable-mass damper to calculate the damper parameters corresponding to each vibration mode as the damper optimization parameters for the single-mode control target. (3) Based on the state space model of the cable-mass damper, multiple sets of curves are plotted within the range of damper parameter values. Each set of curves shows the change of the damping ratio of each vibration mode of the cable with the damping coefficient of the damper. For any curve, the minimum value of the damping ratio of each vibration mode under different damping coefficients is found and connected into a curve. The maximum value point of the damping ratio and its corresponding damping coefficient are further determined on the minimum value curve. (4) Find the global maximum point from the maximum points corresponding to all curves, and use the inertia coefficient and damping coefficient corresponding to the curve to which the point belongs as the damper optimization parameters of the multimodal control target. (5) In the laboratory, the mathematical relationship between the theoretical optimization parameters, physical parameters and control parameters of the damper is calibrated and embedded into the control system in the form of code writing; (6) When the cable vibrates, the damper starts to work. The initial state adopts the damper optimization parameters corresponding to the first-order vibration mode of the cable. At the same time, the control system starts to acquire and process the vibration acceleration signal for vibration mode identification. (7) When the cable experiences abnormal large-amplitude vibration, the vibration acceleration signal is subjected to fast Fourier transform to obtain the signal spectrum information. The control system classifies and identifies whether the vibration is dominated by a single mode or multiple modes based on the spectrum information, thereby adopting the damper optimization parameters corresponding to the control target, and calculating the control parameters based on the mathematical relationship calibrated in the laboratory to control the damper in real time.

Images