An angle active control system based on mass damper

Abstract

The application discloses an angle active control system based on a mass damper in the technical field of active vibration control, which comprises a controlled structure, an angle vibration sensor arranged on the controlled structure, the angle vibration sensor being capable of detecting angle vibration information of the controlled structure, a mass damper arranged on the controlled structure, an internal vibration sensor arranged on a mass block of the mass damper, the internal vibration sensor being capable of detecting linear vibration information of the mass block in a control direction, and a controller, which is in electrical signal connection with the angle vibration sensor, the internal vibration sensor and the mass damper, and is capable of outputting a driving signal for controlling the action of the mass damper to the mass damper according to the received angle vibration information and linear vibration information. The application adopts an internal speed feedback method, improves the gain margin of external speed feedback, and reduces vibration amplification of the mass damper near the natural frequency, so that the active mass damper vibration reduction effect is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of active vibration control, and particularly relates to an angle active control system based on a mass damper. BACKGROUND

[0002] In the field of advanced light sources, the angle stability of optical elements has a very important influence on light beam transmission, which is mainly determined by the vibration of the corresponding optical element adjusting mechanism after being excited by external excitation.

[0003] In order to improve the stability of the device, the inherent frequency of the adjusting mechanism is generally improved by optimizing the mechanical structure design, or the excitation is reduced by passive damping to achieve it. The former has no damping effect on low-frequency vibration, and the latter has low damping efficiency and poor flexibility.

[0004] Active vibration control has good flexibility and high vibration isolation efficiency for modal vibration of the structure, and theoretically has low-frequency vibration isolation capability. Active vibration control relies on actuators to generate secondary excitation to offset the influence of primary excitation on the structure. Generally, active vibration control of precision equipment is carried out by active vibration isolation. There are two methods of arranging actuators for active vibration isolation. The first method is to arrange the actuators in the adjusting mechanism close to the optical element located on the upper layer of the system, and the second method is to arrange the actuators in the foundation support structure close to the ground located on the lower layer of the system. The former has low low-frequency damping efficiency due to the high inherent frequency of the adjusting mechanism, and the latter has high requirements for actuators due to the heavy load.

[0005] In addition, there is another method of active control, which is active mass damping. It generates a secondary force by arranging a mass actuator above the controlled structure. This method has a damping effect on the frequency band higher than the inherent frequency of the mass damper, and can control low-frequency vibration by designing a mass damper with low inherent frequency. However, active mass damping will amplify the vibration near the inherent frequency of the mass damper (i.e. overflow effect), and the degree of vibration amplification is related to the damping size of the mass damper.

[0006] Therefore, how to reduce the vibration amplification of active mass damping near the inherent frequency of the mass damper has become a technical problem to be solved by those skilled in the art. SUMMARY

[0007] Therefore, the purpose of the present application is to provide an angle active control system based on a mass damper to solve the technical problem of vibration amplification of existing active mass damping near the inherent frequency of the mass damper.

[0008] The technical solution adopted by the present application is: an angle active control system based on a mass damper, comprising:

[0009] controlled structure

[0010] an angular vibration sensor, which is arranged on the controlled structure and is capable of detecting angular vibration information of the controlled structure;

[0011] a mass damper, which is arranged on the controlled structure and is capable of outputting a secondary torque to the controlled structure;

[0012] an internal vibration sensor, which is arranged on a mass block of the mass damper and is capable of detecting linear vibration information of the mass block in a control direction;

[0013] a controller, which is electrically connected with the angular vibration sensor, the internal vibration sensor and the mass damper, and is capable of outputting a driving signal for controlling the action of the mass damper to the mass damper according to the received angular vibration information and linear vibration information.

[0014] Preferably, the mass damper comprises a mass block, a connecting frame, elastic sheets and an actuator, the connecting frame is fixedly arranged on the upper surface of the controlled structure, the mass block is arranged inside the connecting frame, in the vertical control direction, two sides of the mass block are fixedly connected with the connecting frame through the elastic sheets; in the control direction, the actuator is arranged between one end of the mass block and the connecting frame, the actuator comprises a moving connecting part and a static connecting part, the static connecting part is fixedly connected with the connecting frame, the moving connecting part is fixedly connected with the mass block, and the internal vibration sensor is installed on the other end of the mass block.

[0015] Preferably, the four elastic sheets are symmetrically arranged on the two sides of the mass block.

[0016] Preferably, the elastic sheet is a stainless steel sheet.

[0017] Preferably, the actuator is a voice coil motor.

[0018] Preferably, the mass damper is arranged at a position away from the center of mass of the controlled structure, and the line connecting the mass damper and the center of mass is perpendicular to the control direction.

[0019] Preferably, the internal vibration sensor is a speed sensor.

[0020] The beneficial effects of the present application are as follows:

[0021] This invention improves the gain margin of external velocity feedback by introducing internal velocity feedback into the mass damper, thereby enhancing the vibration reduction effect near the natural frequency of the main mode of the controlled structure. At the same time, it suppresses the vibration amplification near the natural frequency of the mass damper, thus achieving the vibration reduction effect of active mass damping and improving the angular stability of the device. Attached Figure Description

[0022] Figure 1 This is a top view of the active angle control system based on a mass damper according to the present invention.

[0023] Figure 2 A top view schematic diagram of the mass damper;

[0024] Figure 3 This is a schematic diagram of active mass damping feedback control.

[0025] Figure 4 The frequency response logic diagram for an active mass damping system with internal velocity feedback;

[0026] Figure 5 Example diagram of unity-gain open-loop frequency response for active mass damping with external velocity feedback;

[0027] Figure 6 An example diagram illustrating the control effect of active mass damping with internal velocity feedback.

[0028] Explanation of the reference numerals in the figure:

[0029] 100. Controlled structure;

[0030] 200. Angle vibration sensor;

[0031] 300. Mass damper;

[0032] 310. Mass block; 320. Connecting frame; 330. Elastic sheet; 340. Actuator; 341. Moving connection; 342. Static connection;

[0033] 400. Internal vibration sensor;

[0034] 500, Controller;

[0035] 600. Optical components. Detailed Implementation

[0036] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings. These embodiments are for illustrative purposes only and are not intended to limit the scope of the invention.

[0037] In the description of the present application, it should be noted that the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first", "second" are only for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0038] In the description of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connecting" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0039] In addition, in the description of the present application, unless otherwise specified, the meaning of "multiple" is two or more.

[0040] As shown in the embodiment, an angle active control system based on a mass damper includes: Figures 1-6

[0041] A controlled structure 100, the optical element 600 is fixed on the controlled structure 100.

[0042] An angle vibration sensor 200, the angle vibration sensor 200 is fixedly installed on the controlled structure 100, and the angle vibration sensor 200 can detect the angle vibration information of the controlled structure 100 in the horizontal direction, and the angle vibration information is the feedback error signal of the active mass damper.

[0043] A mass damper 300, the mass damper 300 is installed on the controlled structure 100, and the mass damper 300 can output a secondary torque to the controlled structure 100 under the driving of an external driving signal to control the angle vibration of the controlled structure 100.

[0044] An internal vibration sensor 400, the internal vibration sensor 400 is arranged on the mass block 310 of the mass damper 300, and the internal vibration sensor 400 can detect the linear vibration information of the mass block 310 in the control direction.

[0045] ​a controller 500 electrically connected with the angular vibration sensor 200, the internal vibration sensor 400 and the mass damper 300, and the controller 500 is capable of calculating and outputting a driving signal for controlling the mass damper 300 to act according to the received angular vibration information and linear vibration information.

[0046] The controller 500 in the present application can realize closed-loop feedback control of two error inputs at the same time, wherein the error signal of the first closed-loop feedback control is the angular vibration of the controlled structure 100, and the external velocity feedback can realize the effect of active damping near the natural frequency of the main mode of the controlled structure 100, thereby reducing the vibration near the natural frequency of the main mode of the controlled structure 100. The error signal of the second closed-loop feedback control is the linear vibration of the mass block 310 along the action direction of the actuator 340, and the internal velocity feedback can realize the effect of active damping near the natural frequency of the mass damper 300, thereby increasing the damping of the mass damper 300. The unit gain open-loop response amplitude of the external velocity feedback at the natural frequency of the mass damper 300 will decrease with the increase of the damping of the mass damper 300, and the gain margin of the external velocity feedback is inversely proportional to the open-loop response amplitude, so the internal velocity feedback will improve the gain margin of the external velocity feedback. Under appropriate internal active damping of the mass damper 300, the unit gain open-loop response amplitude of the external velocity feedback near the natural frequency of the main mode of the controlled structure 100 is basically unchanged, and the damping effect near the natural frequency of the main mode of the controlled structure 100 is proportional to the open-loop response amplitude when the gain of the external velocity feedback is the same, so the maximum damping effect of the active mass damper near the natural frequency of the main mode of the controlled structure 100 will increase with the improvement of the gain margin of the external velocity feedback. At the same time, under the condition of larger internal velocity feedback gain and appropriate external velocity feedback gain, the vibration amplification near the natural frequency of the mass damper 300 caused by the active mass damper will be suppressed, thereby improving the damping effect near the natural frequency of the main mode of the controlled structure 100 and suppressing the vibration amplification near the natural frequency of the mass damper 300.

[0047] In a specific embodiment, as Figure 2As shown, the mass damper 300 comprises a mass block 310, a connecting frame 320, elastic sheets 330 and an actuator 340; wherein the connecting frame 320 is in the shape of a mouth word as a whole, and is fixedly installed on the upper surface of the controlled structure 100; the mass block 310 is in the shape of a cuboid as a whole, and is accommodated in the interior of the connecting frame 320; in the vertical control direction, the two sides of the mass block 310 are fixedly connected with the connecting frame 320 through the elastic sheets 330, that is, the elastic sheets 330 are arranged on the left and right sides of the mass block 310, the elastic sheets 330 are arranged along the left and right directions, one end of the elastic sheets 330 is fixedly connected with the mass block 310, and the other end of the elastic sheets 330 is fixedly connected with the connecting frame 320, so as to make the mass block 310 linearly vibrate in the control direction through the elastic deformation of the elastic sheets 330, and to exert a secondary torque on the controlled structure 100 through the connecting frame 320.

[0048] In the control direction, the actuator 340 is arranged between the mass block 310 and the connecting frame 320, that is, in the front and back direction, the actuator 340 is arranged at the front end of the mass block 310 and is located between the mass block 310 and the connecting frame 320; the actuator 340 comprises a dynamic connecting part 341 and a static connecting part 342, the static connecting part 342 is fixedly connected with the connecting frame 320, and the dynamic connecting part 341 is fixedly connected with the mass block 310; the internal vibration sensor 400 is installed at the other end of the mass block 310, that is, the internal vibration sensor 400 is installed at the rear end of the mass block 310.

[0049] Preferably, the number of the elastic sheets 330 is four, and the four elastic sheets 330 are symmetrically arranged on the left and right sides of the mass block 310, so as to make the vibration direction of the mass block 310 consistent with the control direction of the mass damper 300; the connecting frame 320, the mass block 310 and the elastic sheets 330 constitute a single degree of freedom system, and the natural frequency should be lower than the first order natural frequency of the controlled structure 100.

[0050] More preferably, the elastic sheets 330 are stainless steel sheets, so as to ensure higher rigidity in other directions except the control force direction of the mass damper 300.

[0051] Still more preferably, the actuator 340 is a voice coil motor, which is used to exert an interaction force between the controlled structure 100 and the mass block 310, and the action direction of the force is consistent with the control direction of the mass damper 300.

[0052] In a specific embodiment, the mass damper 300 is arranged at a position far away from the mass center of the controlled structure 100, and the connecting line between the mass damper 300 and the mass center is perpendicular to the control direction.

[0053] Preferably, the internal vibration sensor 400 is a velocity sensor, which can measure the vibration of the mass block 310 in the control direction of the mass damper 300, and is used to realize internal velocity feedback.

[0054] In one specific embodiment, the controlled structure 100 can be a single-degree-of-freedom structure or a multi-degree-of-freedom structure.

[0055] The mass damper 300 has a single degree of freedom structure, and the natural frequency of the mass damper 300 is lower than the first natural frequency of the controlled structure 100.

[0056] The angular vibration sensor 200 is achieved by subtracting the signals from two parallel linear sensors.

[0057] In this application, the controller 500 can simultaneously receive angular vibration information from the angular vibration sensor 200 and linear vibration information from the internal vibration sensor 400, and calculate the driving voltage of the actuator 340 based on the angular vibration information and the linear vibration information. Under the drive of the driving voltage, the actuator 340 generates a pair of forces of equal magnitude and opposite direction on the mass block 310 and the connecting frame 320, and the direction of the force is consistent with the direction of the control force of the mass damper 300.

[0058] This application employs an internal velocity feedback method to improve the vibration reduction effect of active mass damping, and achieves this by increasing the gain margin of external velocity feedback and reducing the vibration amplification of the mass damper near its natural frequency.

[0059] The active mass damping feedback control in this application is as follows: Figure 3 As shown, the angular velocity of the controlled structure 100 and the internal velocity of the mass damper 300 The response under the combined action of external excitation and feedback control is measured by a vibration sensor and then acquired by the controller 500, serving as the error for both external and internal velocity feedback. The controller 500 applies gain p to both signals. v1 and p v2 The external speed feedback output signal U′ and the internal speed feedback output signal U″ are then obtained and combined as the actual drive signal U of the actuator 340.

[0060] To explain in detail the principles and effects of active mass damping and internal velocity feedback, Figure 4 The system's frequency response and signal flow graph are defined, with the main transfer functions defined as follows:

[0061]

[0062]

[0063]

[0064]

[0065] It should be noted that the internal speed feedback gain p v2 The above transfer function at the modal natural frequency ω of the controlled structure n The values ​​in the vicinity are not significantly affected, but the natural frequency ω of the mass damper is affected. a The values ​​in the vicinity have a greater impact.

[0066] Figure 5 Without loss of generality, it describes Figure 4 China G s1 (s) varies with the internal velocity feedback coefficient p v2 Changes: with p v2 With the increase of ω, the natural frequency ω of the mass damper a The amplitude of the unity-gain open-loop response in the vicinity decreases significantly, while the natural frequency ω of the controlled structure... n The amplitude of the unity-gain open-loop response remains essentially constant in the vicinity. In a practical system, the curve in the figure can be used as the output signal U′ of external velocity feedback by applying a sinusoidal excitation signal with controllable amplitude and frequency, while simultaneously acquiring the angular velocity of the controlled structure. And perform FFT on it to adjust the excitation frequency. Divide the amplitude by the amplitude of the driving voltage, and then divide the excitation frequency. The phase is obtained by subtracting the phase of the driving voltage.

[0067] Figure 6 The change in vibration transmissivity of a controlled structure under active mass damping control is described, and its calculation method is as follows:

[0068]

[0069] The curves in the figure include:

[0070]

[0071]

[0072]

[0073] The three curves above represent the transmissivity under conditions of no feedback control, maximum gain with only external velocity feedback, and maximum gain with internal velocity feedback, respectively. It can be seen that by adding internal velocity feedback, the active mass damping achieves the same vibration reduction effect near the natural frequency of the controlled structure while effectively suppressing vibration amplification near the natural frequency of the mass damper. Further increasing the external velocity feedback gain (by increasing p) further enhances this effect. v1The damping effect near the natural frequency of the controlled structure will be further improved.

[0074] Compared with the prior art, the present application has at least the following beneficial technical effects:

[0075] The present application measures the angular vibration feedback of the controlled structure to the controller through the vibration sensor, carries out the active mass damper control of the speed feedback, increases the active damping of the mass damper by introducing the internal speed feedback of the mass damper, improves the gain margin of the main feedback, and further improves the damping effect near the natural frequency of the controlled structure, while suppressing the resonance of the mass damper.

[0076] The above only describes the preferred embodiments of the present application, and it should be noted that for ordinary skilled persons in the art, without departing from the technical principles of the present application, a number of improvements and replacements can be made, and these improvements and replacements should also be considered as the protection scope of the present application.

Claims

1. A mass-damper-based active control system for angles, characterized by, include: Controlled structure (100); An angle vibration sensor (200) is disposed on the controlled structure (100) and the angle vibration sensor (200) is capable of detecting the angle vibration information of the controlled structure (100); A mass damper (300) is disposed on the controlled structure (100) and the mass damper (300) is capable of outputting a secondary torque to the controlled structure (100). An internal vibration sensor (400) is disposed on the mass block (310) of the mass damper (300), and the internal vibration sensor (400) is capable of detecting linear vibration information of the mass block (310) in the control direction; The controller (500) is electrically connected to the angular vibration sensor (200), the internal vibration sensor (400) and the mass damper (300), and the controller (500) can output a drive signal to the mass damper (300) for controlling the action of the mass damper (300) according to the received angular vibration information and linear vibration information.

2. The mass damper based active control system for angle according to claim 1, characterized in that, The mass damper (300) includes a mass block (310), a connecting frame (320), an elastic plate (330), and an actuator (340). The connecting frame (320) is fixedly mounted on the upper surface of the controlled structure (100). The mass block (310) is disposed inside the connecting frame (320). In the vertical control direction, both sides of the mass block (310) are fixedly connected to the connecting frame (320) through the elastic plate (330). In the control direction, the actuator (340) is disposed between one end of the mass block (310) and the connecting frame (320). The actuator (340) includes a moving connection part (341) and a stationary connection part (342). The stationary connection part (342) is fixedly connected to the connecting frame (320), and the moving connection part (341) is fixedly connected to the mass block (310). The internal vibration sensor (400) is installed at the other end of the mass block (310).

3. The mass damper based active control system for angle according to claim 2, characterized in that, The four elastic plates (330) are symmetrically arranged on both sides of the mass block (310).

4. The angle active control system based on a mass damper according to claim 3, characterized in that, The elastic sheet (330) is a stainless steel sheet.

5. The angle active control system based on a mass damper according to claim 2, characterized in that, The actuator (340) is a voice coil motor.

6. The active angle control system based on a mass damper according to claim 1, characterized in that, The mass damper (300) is positioned away from the center of mass of the controlled structure (100), and the line connecting the mass damper (300) and the center of mass is perpendicular to the control direction.

7. The active angle control system based on a mass damper according to claim 1, characterized in that, The internal vibration sensor (400) is a velocity sensor.

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