A dual-sensor dual-actuator cooperative active vibration isolation system and method

Abstract

This invention provides an active vibration isolation system and method with dual sensors and dual actuators, relating to the field of active vibration isolation technology. The system includes a moving base, a vibration isolation platform, a relative displacement sensor, an acceleration sensor, an air spring actuator, a voice coil motor actuator, and a controller. The relative displacement sensor acquires the relative displacement signal between the vibration isolation platform and the moving base. The acceleration sensor acquires the vibration acceleration signal of the vibration isolation platform. The controller controls the air spring actuator to perform low-frequency position tracking based on the relative displacement signal, adjusting the low-frequency equilibrium position of the vibration isolation platform relative to the moving base. Based on the vibration feedback obtained from the acceleration sensor, the controller controls the voice coil motor actuator to output active control force to suppress the mid-to-high frequency vibration response of the vibration isolation platform. This avoids problems such as insufficient voice coil motor travel, control failure, or vibration amplification under moving base conditions.

Description

Technical Field

[0001] This invention relates to the field of active vibration isolation technology, and in particular to an active vibration isolation system and method with dual sensors and dual actuators working together. Background Technology

[0002] Active vibration isolation systems are typically used to reduce the transmission of external vibrations to precision loads, experimental platforms, or testing equipment. Most existing active vibration isolation systems are based on the assumption of a rigid foundation or a near-static base. A common active vibration isolation system structure consists of a single type of sensor and a single type of actuator. That is, a vibration sensor acquires vibration information of the isolation platform, and a single type of active actuator applies feedback control force to the isolation platform, thereby reducing the platform's vibration response.

[0003] Under rigid foundation conditions, the mounting base of an active vibration isolation system can be approximated as a static support foundation. In this case, the base itself does not generate significant low-frequency, large displacement motion. Accelerometers are primarily used to acquire vibration feedback signals from the isolation platform, while active actuators such as voice coil motors are mainly used to output short-stroke, high-response active control forces. Based on these conditions, traditional active vibration isolation systems can achieve vibration suppression within a certain frequency band.

[0004] However, in scenarios involving moving bases such as the working basket of a centrifuge operating at high gravity, the installation foundation for the active vibration isolation system is no longer a rigid, static foundation, but a moving base that experiences low-frequency displacement oscillations superimposed with mid-to-high-frequency mechanical vibrations during operation. This moving base generates low-frequency, large-stroke displacement changes and transmits mid-to-high-frequency vibrations caused by mechanical transmission, structural vibrations, or external disturbances to the isolation platform. The simultaneous presence of low-frequency displacement oscillations and mid-to-high-frequency mechanical vibrations presents traditional active vibration isolation systems with control challenges under combined disturbance conditions.

[0005] Traditional single-type sensor active vibration isolation systems suffer from unreliable low-frequency feedback under moving base conditions. Taking piezoelectric accelerometers as an example, they are suitable for measuring the dynamic vibration acceleration of vibration isolation platforms, especially for mid-to-high frequency vibration feedback. However, when the base experiences low-frequency oscillations or attitude changes, the accelerometer output signal is easily affected by insufficient low-frequency response, integral drift, attitude coupling, or changes in the gravitational component. If the accelerometer is still used as a full-frequency feedback element in this scenario, the controller will struggle to accurately distinguish between the low-frequency oscillations of the moving base and the mid-to-high frequency vibrations that need to be actively suppressed, thus affecting the closed-loop control performance.

[0006] Traditional single-actuator active vibration isolation systems suffer from insufficient actuator stroke under moving base conditions. Voice coil motors (VCOs) offer advantages such as fast response, continuously controllable output force, and suitability for mid-to-high frequency active vibration isolation, but their effective stroke is limited. When an active vibration isolation system is installed on a moving base, if the isolation platform is still required to remain nearly stationary relative to inertial space in the low-frequency range, the low-frequency displacement of the moving base will directly translate into a large relative displacement between the isolation platform and the actuator mounting reference. This relative displacement will occupy the effective stroke of the VCO, causing it to deviate from its optimal operating point, potentially leading to insufficient stroke, limited control force, operating point drift, or control saturation.

[0007] Furthermore, when a traditional controller mistakenly interprets the low-frequency oscillation of the moving base as a vibration input that should be directly suppressed by the voice coil motor, the voice coil motor may be forced to undertake a low-frequency, large-stroke compensation task that it is not suited to handle. In this case, the active vibration isolation system not only fails to achieve effective vibration isolation but may also introduce additional control effects to the vibration isolation platform, leading to a deterioration in vibration response or even vibration amplification.

[0008] Therefore, traditional active vibration isolation systems using a single type of sensor and a single type of actuator are difficult to directly apply to moving base conditions. For scenarios such as the working basket of a centrifuge operating under heavy gravity conditions, where low-frequency displacement oscillations coexist with medium- and high-frequency mechanical vibrations, an active vibration isolation system and method are needed that can simultaneously handle low-frequency large-stroke disturbances and medium- and high-frequency vibration disturbances. This allows the low-frequency operating point adjustment task and the medium- and high-frequency active vibration isolation task to be undertaken by suitable sensors and actuators, respectively, thereby avoiding active vibration isolation control failure and vibration isolation amplification under moving base conditions. Summary of the Invention

[0009] To address the problems existing in the prior art, the present invention aims to propose an active vibration isolation system and method with dual sensors and dual actuators working together. This system solves the problems that traditional active vibration isolation systems with single-type sensors and single-type actuators are prone to encounter under moving base conditions, such as unreliable sensor feedback, voice coil motor operating point offset, insufficient actuator stroke, control failure, or vibration isolation amplification.

[0010] The present invention provides an active vibration isolation system and method with dual sensors and dual actuators working together, which adopts the following technical solution: An active vibration isolation system with dual sensors and dual actuators working together, comprising: A moving base located at the bottom position has low-frequency displacement oscillation and superimposed medium- and high-frequency mechanical vibration, the moving base being used to support the active vibration isolation system; A vibration isolation platform is disposed above the motion base, and the vibration isolation platform is used to support the object to be isolated from vibration; An air spring actuator is disposed between the moving base and the vibration isolation platform, and is used to adjust the low-frequency balance position of the vibration isolation platform relative to the moving base; A voice coil motor actuator is disposed between the motion base and the vibration isolation platform, and is used to apply active control force to the vibration isolation platform; A relative displacement sensor is disposed on the motion base to acquire the relative displacement signal between the vibration isolation platform and the motion base. The relative displacement signal is used to characterize the stroke or working point offset of the voice coil motor actuator. An accelerometer is mounted on the vibration isolation platform to acquire the vibration acceleration signal of the vibration isolation platform. The controller is electrically connected to the relative displacement sensor, the acceleration sensor, the air spring actuator, and the voice coil motor actuator.

[0011] By adopting the above technical solutions, an active vibration isolation system architecture suitable for moving base conditions was constructed. By introducing a relative displacement sensor to monitor the stroke or operating point offset of the voice coil motor, and an acceleration sensor to obtain platform vibration, the problem of unreliable feedback from a single sensor in scenarios where low-frequency oscillation and mid-to-high-frequency vibration coexist was solved. At the same time, the use of dual actuators, namely an air spring and a voice coil motor, provided a hardware foundation for subsequent division of labor and cooperation (low-frequency compensation + mid-to-high-frequency vibration suppression).

[0012] Preferably, one end of both the air spring actuator and the voice coil motor actuator is fixedly connected to the motion base, and the other end is fixedly connected to the vibration isolation platform.

[0013] By adopting the above technical solution, the air spring and voice coil motor are installed in parallel between the moving base and the vibration isolation platform, resulting in a stable and reliable structure.

[0014] Preferably, the controller includes a low-frequency position compensation control unit and a medium-to-high frequency active vibration isolation control unit; The low-frequency position compensation control unit is configured to control the air spring actuator according to the relative displacement signal, adjust the low-frequency balance position of the vibration isolation platform relative to the moving base, and keep the stroke or working point of the voice coil motor actuator within a preset working range. The mid-to-high frequency active vibration isolation control unit is configured to control the voice coil motor actuator to output active control force based on the vibration acceleration signal or the vibration feedback amount obtained by processing the vibration acceleration signal, so as to suppress the mid-to-high frequency vibration response of the vibration isolation platform.

[0015] By adopting the above technical solution, the low-frequency position compensation control unit and the mid-to-high frequency active vibration isolation control unit work together to achieve the functional division of "low-frequency operating point adjustment" and "mid-to-high frequency vibration isolation".

[0016] Preferably, both the low-frequency position compensation control unit and the medium-to-high frequency active vibration isolation control unit adopt PID controllers; the control parameters of the PID controllers are obtained by co-tuning the weighted performance indicators constructed based on the fixed structure robust tuning framework and the frequency domain weight function before the system is put into operation.

[0017] By adopting the above technical solution, and using a fixed-structure robust tuning framework and frequency domain weighting function to collaboratively optimize the parameters of the two PID controllers, it is possible to obtain globally optimal parameters that take into account low-frequency operating point adjustment, mid-to-high frequency vibration suppression, and dual actuator control quantity constraints before the system is put into operation, thereby improving the stability of the system under different operating conditions.

[0018] Preferably, the controller further includes a frequency division processing unit, which extracts the low-frequency components of the relative displacement signal and uses the extracted low-frequency travel error signal for the control of the air spring actuator; the frequency division processing unit also extracts the mid-to-high frequency components of the vibration feedback quantity and uses the extracted mid-to-high frequency vibration feedback quantity for the control of the voice coil motor actuator.

[0019] By adopting the above technical solution, low-frequency components of the relative displacement signal are extracted for air spring control, and mid-to-high frequency components of the vibration feedback are extracted for voice coil motor control. This achieves natural division of signal frequency bands, prevents low-frequency displacement signals from accidentally entering the voice coil motor control circuit, and also prevents mid-to-high frequency vibration signals from interfering with air spring control, significantly reducing coupling interference between circuits.

[0020] Preferably, the frequency division processing unit employs a low-pass filter and a high-pass filter; the low-pass filter is used to obtain the low-frequency components in the stroke or operating point offset of the voice coil motor actuator, and the high-pass filter is used to obtain the mid-to-high frequency components in the vibration feedback of the vibration isolation platform, so that the air spring actuator mainly operates in the low-frequency position compensation frequency band, and the voice coil motor actuator mainly operates in the mid-to-high frequency active vibration isolation frequency band.

[0021] By adopting the above technical solution, the air spring is mainly operated in the low-frequency position compensation frequency band by using a low-pass filter, and the voice coil motor is mainly operated in the mid-to-high frequency active vibration isolation frequency band by using a high-pass filter. The two complement each other in the frequency domain, which can ensure both the low-frequency large stroke compensation capability and the mid-to-high frequency fast response vibration suppression capability, and avoid control conflicts or energy waste caused by frequency band overlap.

[0022] Preferably, the motion base is a working basket for a centrifuge, an installation base connected to the working basket for a centrifuge, or a suspended motion platform with low-frequency oscillation characteristics.

[0023] By adopting the above technical solutions, the typical motion base scenarios for which the system is applicable have been identified, providing a solution for vibration isolation of precision equipment in complex disturbance environments such as centrifuges under ultragravity conditions.

[0024] Preferably, the relative displacement sensor is a laser displacement sensor, used to measure the relative displacement of the vibration isolation platform relative to the moving base, or to measure the relative displacement between the structures at both ends of the voice coil motor actuator; The acceleration sensor is a piezoelectric acceleration sensor.

[0025] By adopting the above technical solution, specific sensor selection is given to ensure the accuracy of relative displacement measurement and the high-frequency response performance of vibration acceleration measurement.

[0026] An active vibration isolation method using dual sensors and dual actuators is applied to the aforementioned active vibration isolation system using dual sensors and dual actuators. The active vibration isolation method using dual sensors and dual actuators includes the following steps: S1. Both the air spring actuator and the voice coil motor actuator are positioned between the motion base and the vibration isolation platform; S2. Obtain the relative displacement signal between the vibration isolation platform and the moving base through a relative displacement sensor, and use the relative displacement signal as a feedback signal characterizing the stroke or working point offset of the voice coil motor actuator. S3. The controller calculates the stroke error or operating point deviation of the voice coil motor actuator based on the relative displacement signal, and extracts the low-frequency stroke error signal through the frequency division processing unit; the low-frequency position compensation control unit generates an air spring control input based on the low-frequency stroke error signal, and the air spring actuator adjusts the low-frequency position or low-frequency balance position of the vibration isolation platform relative to the moving base based on the air spring control input, so that the voice coil motor actuator is kept within the preset working stroke range; S4. Obtain the vibration acceleration signal of the vibration isolation platform through an accelerometer, and filter, integrate, and de-trend integrate the vibration acceleration signal to obtain the vibration feedback quantity for medium- and high-frequency active vibration isolation control. The vibration feedback quantity is the vibration velocity signal of the vibration isolation platform. ; S5. While the voice coil motor actuator is kept within the preset working stroke range, the frequency division processing unit extracts the mid-to-high frequency components of the vibration feedback quantity to obtain the mid-to-high frequency vibration feedback quantity; the mid-to-high frequency active vibration isolation control unit generates the voice coil motor control input according to the mid-to-high frequency vibration feedback quantity, and the voice coil motor actuator outputs the active control force according to the voice coil motor control input to suppress the mid-to-high frequency vibration response of the vibration isolation platform; S6. The air spring actuator and the voice coil motor actuator are controlled in a coordinated manner, so that the air spring actuator prioritizes to compensate for the offset of the voice coil motor operating point caused by the low-frequency displacement swing of the moving base, and the voice coil motor actuator performs mid-to-high frequency active vibration isolation while keeping the operating point within the preset operating range, thereby avoiding the failure of active vibration isolation control or vibration isolation amplification under the condition of the moving base.

[0027] By adopting the above technical solution, a complete process from sensor signal acquisition, frequency division processing, actuator control to collaborative work is provided, which avoids common problems such as control failure, insufficient stroke, and vibration isolation amplification under moving base conditions, and achieves effective vibration isolation under complex disturbance environment.

[0028] Preferably, the relative displacement signal is represented as: ; in, This refers to the stroke or operating point offset of the voice coil motor actuator. The location of the vibration isolation platform. The position of the moving base; set up If the voice coil motor actuator is in its preset working position or target working gap, then the low-frequency stroke error signal is expressed as: ; in, This is the stroke error signal after low-frequency component extraction. This is a low-frequency component extraction step. relative displacement signal Laplace transform, For the target work location The Laplace transform of; The air spring control input is represented as follows: ; in, This is the control input for the air spring actuator. For low-frequency position compensation controller of air spring; The mid-to-high frequency vibration feedback quantity is expressed as: ; in, This is the mid-to-high frequency vibration feedback quantity used for voice coil motor actuator control. This is the extraction stage for medium- and high-frequency components. Vibration velocity signal of the vibration isolation platform; The voice coil motor control input is represented as follows: ; in, It serves as the control input or active control force command for the voice coil motor actuator. It is a high-frequency active vibration isolation controller for voice coil motors.

[0029] By adopting the above technical solutions, clear mathematical definitions and transmission relationships of key signals such as relative displacement, low-frequency travel error, air spring control input, mid-to-high frequency vibration feedback, and voice coil motor control input are given. These expressions provide quantifiable design basis for engineering implementation, which facilitates controller design, parameter tuning, simulation verification, and code implementation, and ensures the reproducibility and engineering feasibility of the collaborative control strategy.

[0030] In summary, the present invention has at least one of the following beneficial technical effects: 1. By setting up a low-frequency position compensation channel for the air spring, the low-frequency oscillation of the moving base is no longer mainly borne by the voice coil motor actuator, thereby enabling the mid-to-high frequency active vibration isolation channel to maintain normal operation.

[0031] 2. This invention uses an air spring actuator to adjust the low-frequency position or low-frequency balance position of the vibration isolation platform relative to the moving base, so that the relative displacement between the mover and stator of the voice coil motor actuator is kept within a preset stroke range, creating stable working conditions for the voice coil motor actuator to perform mid-to-high frequency active vibration isolation.

[0032] 3. This invention divides the functions of air spring actuators and voice coil motor actuators according to their physical characteristics, so that different actuators can play their roles in their respective suitable frequency bands and working ranges, thus realizing the functional division of low-frequency large-stroke compensation and mid-to-high frequency active vibration isolation.

[0033] 4. This invention uses a relative displacement sensor to obtain the travel or operating point offset information of the voice coil motor, and an acceleration sensor to obtain the vibration information of the vibration isolation platform. Low-frequency compensation and mid-to-high-frequency vibration suppression are performed through air spring actuators and voice coil motor actuators, respectively, which can better adapt to complex disturbance environments.

[0034] 5. This invention independently compensates for the low-frequency operating point offset by using a relative displacement sensor and an air spring actuator, reducing the interference of low-frequency oscillation on the mid-to-high frequency active vibration isolation channel, thereby reducing the risk of vibration isolation performance deterioration and vibration isolation amplification.

[0035] 6. The system provided by this invention can be used for the working basket of a centrifuge with high gravity, the mounting base connected to the working basket of a centrifuge with high gravity, and the suspended motion platform with low-frequency oscillation characteristics, providing a new system architecture and control method for vibration isolation of precision experimental equipment under motion base conditions. Attached Figure Description

[0036] To more clearly illustrate the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below. Obviously, the drawings described below are only preferred embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0037] Figure 1 This is a schematic diagram of the overall structure of the active vibration isolation system with dual sensors and dual actuators in cooperation according to the present invention; Figure 2 This is a block diagram of the dual-channel control of the low-frequency position compensation channel of the air spring and the high-frequency active vibration isolation channel of the voice coil motor in this invention. Figure 3 This is a flowchart of the active vibration isolation method of the present invention, which uses dual sensors and dual actuators in coordination.

[0038] Explanation of reference numerals in the attached drawings: 1. Motion base; 2. Vibration isolation platform; 3. Relative displacement sensor; 4. Acceleration sensor; 5. Air spring actuator; 6. Voice coil motor actuator; 7. Controller; 71. Low-frequency position compensation control unit; 72. Medium- and high-frequency active vibration isolation control unit; 73. Frequency division processing unit; 8. Object to be isolated. Detailed Implementation

[0039] The specific embodiments of the present invention will be further described below with reference to the accompanying drawings. It should be understood that the following embodiments are only for illustrating the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. For those skilled in the art, equivalent substitutions or conventional modifications made to related structures, connection methods, control parameters, or execution steps without departing from the concept of the present invention should all fall within the scope of protection of the present invention.

[0040] like Figure 1 and Figure 2 As shown, this embodiment discloses an active vibration isolation system with dual sensors and dual actuators working together, including: The motion base 1 located at the bottom has low-frequency displacement oscillation and superimposed medium- and high-frequency mechanical vibration. The motion base 1 can be the working basket of the centrifuge or the installation base connected to the working basket of the centrifuge. The motion base 1 is used to support the active vibration isolation system. Vibration isolation platform 2 is disposed above the motion base 1. The vibration isolation platform 2 is used to support the object to be isolated from vibration 8. The object to be isolated from vibration 8 can be a precision experimental device, a precision measuring device, a microscopic imaging device, or other loads that are sensitive to vibration. An air spring actuator 5 is disposed between the moving base 1 and the vibration isolation platform 2, and is used to adjust the low-frequency balance position of the vibration isolation platform 2 relative to the moving base 1. Specifically, the air spring actuator 5 can change the position state of the vibration isolation platform 2 relative to the moving base 1 by adjusting its air chamber pressure, equivalent output force, equivalent stiffness or low-frequency balance position, thereby compensating for the offset of the voice coil motor operating point caused by the low-frequency displacement oscillation of the moving base 1. A voice coil motor actuator 6 is disposed between the motion base 1 and the vibration isolation platform 2, and is used to apply active control force to the vibration isolation platform 2. Specifically, after the air spring actuator 5 completes low-frequency position compensation and operating point adjustment, the relative displacement between the mover and stator of the voice coil motor actuator 6 is maintained within a preset working stroke range, so that the voice coil motor actuator 6 can output active control force near a reasonable operating point. The preset working range refers to the allowable working interval in which the voice coil motor actuator 6 can normally output active control force. It includes the preset working position and the allowable stroke offset range set around the preset working position. The preset working position is the position of the moving part and the stator of the voice coil motor actuator 6 when the active vibration isolation system is in a static base state or in a calibrated state after low-frequency displacement oscillation is compensated, and the position is relatively centered or close to the optimal force output state. The allowable stroke offset range is determined according to the rated effective stroke, linear output force range, mechanical non-interference condition and safety margin of the voice coil motor actuator 6. A relative displacement sensor 3 is disposed on the moving base 1 and is used to acquire the relative displacement signal between the vibration isolation platform 2 and the moving base 1. The relative displacement signal is used to characterize the stroke or operating point offset of the voice coil motor actuator 6. The relative displacement sensor 3 can be a laser displacement sensor. In other embodiments, an eddy current displacement sensor or other sensors capable of measuring relative displacement can also be considered. It is mainly used to measure the relative displacement of the vibration isolation platform relative to the moving base, or to measure the relative displacement between the structures at both ends of the voice coil motor actuator. Accelerometer 4 is disposed on the vibration isolation platform 2 and is used to acquire the vibration acceleration signal of the vibration isolation platform 2. The acceleration sensor 4 may be a piezoelectric acceleration sensor. The controller 7 is electrically connected to the relative displacement sensor 3, the acceleration sensor 4, the air spring actuator 5, and the voice coil motor actuator 6.

[0041] One end of both the air spring actuator 5 and the voice coil motor actuator 6 is fixedly connected to the motion base 1, and the other end is fixedly connected to the vibration isolation platform 2. The air spring actuator 5 and the voice coil motor actuator 6 form a parallel or equivalent parallel dual actuator structure. The air spring actuator 5 mainly undertakes the tasks of low-frequency large-stroke position compensation and voice coil motor operating point adjustment, while the voice coil motor actuator 6 mainly undertakes the tasks of mid-to-high frequency active vibration isolation.

[0042] The controller 7 includes a low-frequency position compensation control unit 71 and a medium-to-high frequency active vibration isolation control unit 72; The low-frequency position compensation control unit 71 is configured to control the air spring actuator 5 according to the relative displacement signal, adjust the low-frequency balance position of the vibration isolation platform 2 relative to the moving base 1, so that the stroke or working point of the voice coil motor actuator 6 is kept within a preset working range. The mid-to-high frequency active vibration isolation control unit 72 is configured to control the voice coil motor actuator 6 to output active control force based on the vibration acceleration signal or the vibration feedback amount obtained by processing the vibration acceleration signal, so as to suppress the mid-to-high frequency vibration response of the vibration isolation platform 2.

[0043] Both the low-frequency position compensation control unit 71 and the medium-high frequency active vibration isolation control unit 72 adopt PID controllers; the control parameters of the PID controllers are obtained by co-tuning the weighted performance indicators constructed based on the fixed structure robust tuning framework and frequency domain weight function before the system is put into operation.

[0044] The controller 7 further includes a frequency division processing unit 73, which extracts the low-frequency components of the relative displacement signal and uses the extracted low-frequency travel error signal for the control of the air spring actuator 5; the frequency division processing unit 73 also extracts the mid-to-high frequency components of the vibration feedback quantity and uses the extracted mid-to-high frequency vibration feedback quantity for the control of the voice coil motor actuator 6.

[0045] The frequency division processing unit 73 employs a low-pass filter and a high-pass filter; the low-pass filter is used to obtain the low-frequency components in the stroke or working point offset of the voice coil motor actuator 6, and the high-pass filter is used to obtain the mid-to-high frequency components in the vibration feedback of the vibration isolation platform 2, so that the air spring actuator 5 mainly operates in the low-frequency position compensation frequency band, and the voice coil motor actuator 6 mainly operates in the mid-to-high frequency active vibration isolation frequency band.

[0046] like Figure 3As shown, an active vibration isolation method using dual sensors and dual actuators is applied to the aforementioned active vibration isolation system. The active vibration isolation method using dual sensors and dual actuators includes the following steps: S1. Both the air spring actuator 5 and the voice coil motor actuator 6 are positioned between the moving base 1 and the vibration isolation platform 2, so that the air spring actuator 5 is used to adjust the low-frequency position of the vibration isolation platform 2 relative to the moving base 1, and the voice coil motor actuator 6 is used to apply active control force to the vibration isolation platform 2.

[0047] S2. The relative displacement signal between the vibration isolation platform 2 and the motion base 1 is obtained by the relative displacement sensor 3, and the relative displacement signal is used as a feedback signal to characterize the stroke or working point offset of the voice coil motor actuator 6. To facilitate the explanation of the synergistic relationship between the low-frequency position compensation channel and the mid-to-high-frequency active vibration isolation channel, the relative displacement signal can be expressed as: ; in, This indicates the stroke or operating point offset of the voice coil motor actuator 6. This indicates the location of vibration isolation platform 2. Indicates the position of the motion base 1; After the relative displacement sensor 3 acquires the relative displacement signal, it sends it to the controller 7. The controller 7 determines whether the voice coil motor actuator 6 deviates from the preset working range based on the relative displacement signal, and adjusts the low-frequency position or low-frequency balance position of the vibration isolation platform 2 relative to the moving base 1 through the air spring actuator 5.

[0048] S3. In the low-frequency position compensation channel, the controller 7 calculates the stroke error or operating point deviation of the voice coil motor actuator 6 based on the relative displacement signal, and extracts the low-frequency stroke error signal through the frequency division processing unit 73; assuming If the preset working position or target working gap of the voice coil motor actuator 6 is the setting, then the low-frequency stroke error signal can be expressed as: ; in, This represents the stroke error signal after low-frequency component extraction. This is a low-frequency component extraction step. relative displacement signal Laplace transform, For the target work location Laplace transform; The low-frequency position compensation control unit 71 generates an air spring control input based on the low-frequency travel error signal. The air spring actuator 5 adjusts the low-frequency position or low-frequency balance position of the vibration isolation platform 2 relative to the moving base 1 according to the air spring control input, so that the voice coil motor actuator 6 is kept within a preset working travel range. The air spring control input can be expressed as: ; in, This indicates the control input for the air spring actuator 5. This refers to a low-frequency position compensation controller for air springs. The above expression is used to describe the control relationship of the air spring actuator 6 for position compensation based on low-frequency relative displacement error, without limiting the specific pneumatic model, valve control structure, gas flow model or specific control parameters of the air spring actuator 6.

[0049] S4. In the mid-to-high frequency active vibration isolation channel, the vibration acceleration signal of the vibration isolation platform 2 is acquired through the acceleration sensor 4, and the vibration acceleration signal is filtered, integrated, and de-trended integrated to obtain the vibration feedback quantity for mid-to-high frequency active vibration isolation control. The vibration feedback quantity can be the vibration velocity signal of the vibration isolation platform 2. .

[0050] S5. While the voice coil motor actuator 6 remains within a preset working stroke range, the frequency division processing unit 73 extracts the mid-to-high frequency components of the vibration feedback quantity to obtain the mid-to-high frequency vibration feedback quantity; the mid-to-high frequency vibration feedback quantity can be expressed as: ; in, This represents the mid-to-high frequency vibration feedback quantity used for controlling the voice coil motor actuator 6. This is the extraction stage for medium- and high-frequency components. This represents the vibration velocity signal of vibration isolation platform 2; The mid-to-high frequency active vibration isolation control unit 72 generates a voice coil motor control input based on the mid-to-high frequency vibration feedback, and the voice coil motor actuator 6 outputs an active control force based on the voice coil motor control input to suppress the mid-to-high frequency vibration response of the vibration isolation platform 2; the voice coil motor control input can be expressed as: ; in, This serves as the control input or active control force command for the voice coil motor actuator 6. For high-frequency active vibration isolation controllers of voice coil motors; The above expression is used to describe the control relationship of the voice coil motor actuator 6 for active vibration isolation based on the mid-to-high frequency vibration feedback, without limiting the specific electrical model, current loop model, drive circuit structure or specific control parameters of the voice coil motor actuator 6.

[0051] In this embodiment, the low-frequency component extraction step and the extraction of medium and high frequency components Low-pass filters, high-pass filters, complementary filters, or other signal processing steps capable of frequency band division can be used. For example, the two can satisfy the following frequency division relationship: ; Through the above frequency division processing, the air spring actuator 5 mainly receives the low-frequency components in the stroke or working point offset of the voice coil motor actuator 6, and the voice coil motor actuator 6 mainly receives the mid-to-high frequency components in the vibration feedback of the vibration isolation platform 2. Therefore, the air spring actuator 5 does not undertake the mid-to-high frequency active vibration isolation task, and the voice coil motor actuator 6 does not undertake the main stroke compensation task corresponding to the low-frequency displacement swing of the moving base 1, thereby realizing the collaborative division of labor between low-frequency position compensation and mid-to-high frequency active vibration isolation.

[0052] S6 and controller 7 coordinate control of the air spring actuator and the voice coil motor actuator through frequency band division, signal filtering and pre-tuned control parameters. This allows the air spring actuator to prioritize compensation for the shift in the operating point of the voice coil motor caused by the low-frequency displacement oscillation of the moving base. This enables the voice coil motor actuator to perform active vibration isolation at medium and high frequencies while keeping the operating point within the preset operating range, thereby avoiding failure of active vibration isolation control or amplification of vibration isolation under moving base conditions.

[0053] Furthermore, before the system is put into operation, the control parameters of the low-frequency position compensation control unit 81 and the medium-to-high frequency active vibration isolation control unit 72 in controller 7 can be pre-tuned under a fixed structure robust tuning framework. Assume an air spring low-frequency position compensation controller... High-frequency active vibration isolation controller for voice coil motors The set of parameters to be tuned is: ; in, The parameters for the low-frequency position compensation controller for the air spring are... These are the parameters for the high-frequency active vibration isolation controller in a voice coil motor.

[0054] To simultaneously consider the stroke error of the voice coil motor actuator 6, the mid-to-high frequency vibration response of the vibration isolation platform 2, the control input of the air spring actuator 5, and the control input of the voice coil motor actuator 6, the following weighted performance output can be constructed: ; in, The frequency domain weighting function is the one corresponding to the travel error or operating point offset. The frequency domain weighting function is the function corresponding to the high-frequency vibration response in vibration isolation platform 2. The frequency domain weighting function corresponding to the control input of the air spring actuator 5. The frequency domain weighting function is the control input for the voice coil motor actuator 6.

[0055] By configuring weights within different frequency bands, the constraint weight on the operating point offset of the voice coil motor actuator 6 in the low-frequency band can be increased, the suppression weight on the vibration response of the vibration isolation platform 2 in the mid-to-high frequency band can be increased, and the control input of the air spring actuator 5 and the voice coil motor actuator 6 can be limited. Thus, the weighted performance index can simultaneously address low-frequency operating point adjustment, mid-to-high frequency vibration suppression, and dual-actuator control quantity constraints within the same tuning framework.

[0056] In this embodiment, the control parameters can be pre-tuned based on the following general objective: ; in, This represents the process from external disturbance input to weighted performance output. The closed-loop transmission relationship. This indicates the selectable range of parameters for the fixed structure controller. This represents the control parameters obtained through pre-tuning. The above tuning objective is used to express the idea of ​​co-tuning the parameters of a fixed-structure controller under the constraints of frequency domain weighting functions and weighted performance indicators. It does not limit the use of a specific tuning algorithm, a specific weighting function form, a specific frequency division, or a specific parameter value.

[0057] During system operation, the low-frequency position compensation control unit 71 and the medium-to-high frequency active vibration isolation control unit 72 operate according to the pre-tuned parameters. Execution control. The control parameters are tuned before the system is put into operation and are used as fixed control parameters during operation. During operation, the controller 7 calculates the control inputs of the air spring actuator 5 and the voice coil motor actuator 6 based on the real-time collected relative displacement signal and vibration feedback, but it does not need to set up an online parameter tuning unit during operation, nor does it need to change the frequency domain weighting function or re-solve the weighted performance index during operation.

[0058] In this manner, the air spring actuator 5 prioritizes the task of adjusting the operating point of the voice coil motor caused by the low-frequency displacement oscillation of the moving base 1, while the voice coil motor actuator 6 undertakes the task of active vibration isolation in the mid-to-high frequency range within its preset operating range. Thus, this invention allocates the low-frequency large-stroke position compensation task and the mid-to-high frequency active vibration isolation task to different actuators, avoiding problems such as insufficient stroke, operating point drift, control failure, or vibration amplification caused by a single actuator simultaneously undertaking full-frequency control tasks.

[0059] In other embodiments, the low-frequency position compensation of the air spring actuator 5 is not limited to being achieved through a specific valve-controlled inflation / deflation mechanism, but can also be achieved through a proportional valve, a switching valve, a pressure regulating component, an air source regulating component, or other pneumatic regulating mechanisms capable of changing the output state of the air spring. Any invention that can adjust the low-frequency position or low-frequency equilibrium position of the vibration isolation platform 2 relative to the moving base 1 according to the relative displacement signal, and keep the voice coil motor actuator 6 within a preset working stroke range, falls within the technical concept of this invention.

[0060] In other embodiments, the low-frequency large-stroke compensation actuator is not limited to the air spring actuator 5, but can also be a pneumatic actuator, hydraulic actuator, electric linear actuator, or other actuator suitable for low-frequency large-stroke compensation; the medium- and high-frequency active vibration isolation actuator is not limited to the voice coil motor actuator 6, but can also be an electromagnetic actuator, piezoelectric actuator, or other actuator suitable for medium- and high-frequency active control. The relative displacement sensor 3 is not limited to a laser displacement sensor, and the acceleration sensor 4 is not limited to a piezoelectric acceleration sensor.

[0061] In other embodiments, the active vibration isolation system can employ a single-degree-of-freedom vibration isolation unit, or it can be expanded into a multi-degree-of-freedom vibration isolation system according to the support requirements of the object being isolated 8. When expanded into a multi-degree-of-freedom vibration isolation system, corresponding relative displacement sensors 3, acceleration sensors 4, air spring actuators 5, and voice coil motor actuators 6 can be respectively set in multiple degrees of freedom directions, or the multi-degree-of-freedom motion control problem can be decomposed into several equivalent single-degree-of-freedom control channels through motion state synthesis and control force distribution. Each equivalent single-degree-of-freedom control channel can adopt the above-mentioned low-frequency position compensation and mid-to-high-frequency active vibration isolation coordinated control method.

[0062] The above are all preferred embodiments of this application and are not intended to limit the scope of protection of this application. Any equivalent substitutions, conventional modifications, or combinations made within the technical concept of this invention to the system structure, sensor type, actuator type, controller structure, frequency division method, weighting function form, or control parameter tuning method shall fall within the scope of protection of this invention.

Claims

1. An active vibration isolation system with dual sensors and dual actuators working in concert, characterized in that, include: A motion base (1) located at the bottom position has low-frequency displacement oscillation and superimposed medium- and high-frequency mechanical vibration, the motion base (1) is used to support the active vibration isolation system; Vibration isolation platform (2) is disposed above the motion base (1) and is used to support the object to be isolated (8). An air spring actuator (5) is disposed between the motion base (1) and the vibration isolation platform (2) for adjusting the low-frequency balance position of the vibration isolation platform (2) relative to the motion base (1); A voice coil motor actuator (6) is disposed between the motion base (1) and the vibration isolation platform (2) and is used to apply active control force to the vibration isolation platform (2); A relative displacement sensor (3) is disposed on the motion base (1) to obtain the relative displacement signal between the vibration isolation platform (2) and the motion base (1). The relative displacement signal is used to characterize the stroke or working point offset of the voice coil motor actuator (6). An acceleration sensor (4) is disposed on the vibration isolation platform (2) and is used to acquire the vibration acceleration signal of the vibration isolation platform (2); The controller (7) is electrically connected to the relative displacement sensor (3), the acceleration sensor (4), the air spring actuator (5), and the voice coil motor actuator (6).

2. The active vibration isolation system with dual sensors and dual actuators as described in claim 1, characterized in that: One end of the air spring actuator (5) and the voice coil motor actuator (6) are fixedly connected to the motion base (1), and the other end is fixedly connected to the vibration isolation platform (2).

3. The active vibration isolation system with dual sensors and dual actuators as described in claim 1, characterized in that: The controller (7) includes a low-frequency position compensation control unit (71) and a medium- and high-frequency active vibration isolation control unit (72). The low-frequency position compensation control unit (71) is configured to control the air spring actuator (5) according to the relative displacement signal, adjust the low-frequency balance position of the vibration isolation platform (2) relative to the moving base (1), and keep the stroke or working point of the voice coil motor actuator (6) within a preset working range; The mid-to-high frequency active vibration isolation control unit (72) is configured to control the voice coil motor actuator (6) to output active control force based on the vibration acceleration signal or the vibration feedback amount obtained by processing the vibration acceleration signal, so as to suppress the mid-to-high frequency vibration response of the vibration isolation platform (2).

4. The active vibration isolation system with dual sensors and dual actuators as described in claim 3, characterized in that: Both the low-frequency position compensation control unit (71) and the medium-high frequency active vibration isolation control unit (72) adopt PID controllers; the control parameters of the PID controllers are obtained by co-tuning the weighted performance index constructed based on the fixed structure robust tuning framework and frequency domain weight function before the system is put into operation.

5. The active vibration isolation system with dual sensors and dual actuators as described in claim 3, characterized in that: The controller (7) further includes a frequency division processing unit (73), which extracts the low-frequency components of the relative displacement signal and uses the extracted low-frequency stroke error signal for the control of the air spring actuator (5); the frequency division processing unit (73) also extracts the mid-to-high frequency components of the vibration feedback quantity and uses the extracted mid-to-high frequency vibration feedback quantity for the control of the voice coil motor actuator (6).

6. The active vibration isolation system with dual sensors and dual actuators as described in claim 5, characterized in that: The frequency division processing unit (73) employs a low-pass filter and a high-pass filter; the low-pass filter is used to obtain the low-frequency components in the stroke or working point offset of the voice coil motor actuator (6), and the high-pass filter is used to obtain the mid-to-high frequency components in the vibration feedback of the vibration isolation platform (2), so that the air spring actuator (5) mainly works in the low-frequency position compensation frequency band, and the voice coil motor actuator (6) mainly works in the mid-to-high frequency active vibration isolation frequency band.

7. The active vibration isolation system with dual sensors and dual actuators as described in claim 1, characterized in that: The motion base (1) is a working basket for a centrifuge, an installation base connected to the working basket for a centrifuge, or a suspended motion platform with low-frequency oscillation characteristics.

8. The active vibration isolation system with dual sensors and dual actuators as described in claim 1, characterized in that: The relative displacement sensor (3) is a laser displacement sensor, used to measure the relative displacement of the vibration isolation platform relative to the moving base, or to measure the relative displacement between the two ends of the voice coil motor actuator; The acceleration sensor (4) is a piezoelectric acceleration sensor.

9. A method for active vibration isolation using dual sensors and dual actuators in coordination, characterized in that, The dual-sensor, dual-actuator cooperative active vibration isolation method is applied to the dual-sensor, dual-actuator cooperative active vibration isolation system according to any one of claims 1-8, and the dual-sensor, dual-actuator cooperative active vibration isolation method includes the following steps: S1. The air spring actuator (5) and the voice coil motor actuator (6) are both placed between the motion base (1) and the vibration isolation platform (2); S2. Obtain the relative displacement signal between the vibration isolation platform (2) and the motion base (1) through the relative displacement sensor (3), and use the relative displacement signal as a feedback signal characterizing the stroke or working point offset of the voice coil motor actuator (6); S3. The controller (7) calculates the stroke error or working point deviation of the voice coil motor actuator (6) according to the relative displacement signal, and extracts the low-frequency stroke error signal through the frequency division processing unit (73); the low-frequency position compensation control unit (71) generates the air spring control input according to the low-frequency stroke error signal, and the air spring actuator (5) adjusts the low-frequency position or low-frequency balance position of the vibration isolation platform (2) relative to the moving base (1) according to the air spring control input, so that the voice coil motor actuator (6) is kept within the preset working stroke range; S4. Obtain the vibration acceleration signal of the vibration isolation platform (2) through the accelerometer (4), and filter, integrate, and de-trend integrate the vibration acceleration signal to obtain the vibration feedback quantity for medium- and high-frequency active vibration isolation control. The vibration feedback quantity is the vibration velocity signal of the vibration isolation platform (2). ; S5. While the voice coil motor actuator (6) is kept within the preset working stroke range, the frequency division processing unit (73) extracts the mid-to-high frequency components of the vibration feedback quantity to obtain the mid-to-high frequency vibration feedback quantity; the mid-to-high frequency active vibration isolation control unit (72) generates the voice coil motor control input according to the mid-to-high frequency vibration feedback quantity, and the voice coil motor actuator (6) outputs the active control force according to the voice coil motor control input to suppress the mid-to-high frequency vibration response of the vibration isolation platform (2); S6. The air spring actuator and the voice coil motor actuator are controlled in a coordinated manner, so that the air spring actuator prioritizes to compensate for the offset of the voice coil motor operating point caused by the low-frequency displacement swing of the moving base, and the voice coil motor actuator performs mid-to-high frequency active vibration isolation while keeping the operating point within the preset operating range, thereby avoiding the failure of active vibration isolation control or vibration isolation amplification under the condition of the moving base.

10. The active vibration isolation method with dual sensors and dual actuators as described in claim 9, characterized in that: The relative displacement signal is represented as: ； in, This refers to the stroke or operating point offset of the voice coil motor actuator (6). The location of the vibration isolation platform (2) is shown. The position of the motion base (1); set up If the voice coil motor actuator (6) is in its preset working position or target working gap, then the low-frequency stroke error signal is expressed as: ； in, This is the stroke error signal after low-frequency component extraction. This is a low-frequency component extraction step. relative displacement signal Laplace transform, For the target work location The Laplace transform of; The air spring control input is represented as follows: ； in, For the control input of the air spring actuator (5), For low-frequency position compensation controller of air spring; The mid-to-high frequency vibration feedback quantity is expressed as: ； in, For the mid-to-high frequency vibration feedback quantity used in the control of the voice coil motor actuator (6), This is the extraction stage for medium- and high-frequency components. Vibration velocity signal of the vibration isolation platform (2); The voice coil motor control input is represented as follows: ； in, For the control input or active control force command of the voice coil motor actuator (6), It is a high-frequency active vibration isolation controller for voice coil motors.

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