Precise VC standard micro-vibration environment simulation method based on ground-based feedforward
Through passive vibration isolation unit and feedforward control technology, combined with foundation vibration sensors and actuators, feedforward controllers and inverse model filters are designed, which solves the problem of traditional simulation platforms being affected by ground vibration, and realizes lower-level micro-vibration environment simulation, provides unified testing standards, and improves equipment reliability.
Patent Information
- Application Number
- CN202510356265.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-25
- Publication Date
- 2025-08-05
AI Technical Summary
Traditional micro-vibration simulation platforms are affected by ground vibration and are difficult to reach a lower level VC level, resulting in equipment meeting standards in laboratory but operating abnormally in actual applications.
The passive vibration isolation unit is combined with feedforward control, and the feedforward controller and inverse model filter are designed through the foundation vibration sensor and actuator, and the active excitation is used to simulate a lower-level micro-vibration environment.
It realizes lower-level micro-vibration environment simulation, provides unified vibration testing standards, and improves equipment reliability and environmental adaptability.
Smart Images
Figure CN120427207A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of vibration testing and debugging of precision equipment, and in particular to a precision VC standard micro-vibration environment simulation method based on ground-based feedforward. Background Art
[0002] To ensure the stable operation of precision instruments and equipment, environmental vibration conditions are one of the key influencing factors. The VC level vibration standard is a common evaluation system in engineering practice, which adopts a 1 / 3 octave band analysis method. In environmental vibration, ground vibration is the main factor, which will change significantly in different application scenarios. This will cause equipment that meets performance standards in laboratory environments to operate abnormally in actual industrial applications. In order to establish a unified vibration test standard, the micro-vibration environment simulation platform can effectively coordinate the consistency of vibration environment requirements between equipment manufacturers and users. The micro-vibration level that can be achieved by traditional micro-vibration simulation platforms is affected by ground vibration, which limits the lowest micro-vibration level that the simulation platform can achieve. In order to simulate lower levels of VC levels, additional measures are needed to suppress the impact of ground vibration. Summary of the Invention
[0003] In light of this, the present invention proposes a precise VC standard microvibration environment simulation method based on ground-based feedforward. This method employs passive vibration isolation units combined with feedforward control to further suppress ground vibration while supporting the platform, thereby achieving even lower microvibration levels. Furthermore, active excitation is used to simulate the microvibration environment, providing multiple levels of microvibration testing environments and establishing a unified standard for equipment production and delivery.
[0004] The technical solution of the present invention is specifically described as follows.
[0005] The present invention provides a method for simulating a precise VC standard micro-vibration environment based on ground-based feedforward, comprising the following steps:
[0006] 1) Construction of a micro-vibration environment simulation platform: The micro-vibration environment simulation platform adopts an active-passive combined design architecture, which includes a passive vibration isolation unit, a platform, a foundation vibration sensor, and an actuator. The passive vibration isolation unit serves as the foundation of the platform support, and the foundation vibration sensor is used to sense foundation vibration. The actuator is used to output feedforward control force and serve as an active excitation source for micro-vibration environment simulation.
[0007] 2) Assume that the transfer function from the force to the response of the micro-vibration environment simulation platform is Gp. According to the force part of the transfer function combined with the bandpass filter, the feedforward controller G is obtained. ff ; The foundation vibration signal S obtained by the foundation vibration sensor ground Through the feedforward controller G ff , get the real-time feedforward control signal Uff ;
[0008] 3) Based on the VC vibration level standard, the spectrum is quantized into a discrete spectrum through the spectrum conversion method, and the spectrum inversion method is used to reconstruct the time domain vibration excitation signal x(n) that conforms to the spectrum characteristics, where n = 0, 1, 2, ..., N-1, where N is the number of points in the spectrum;
[0009] 4) Assume that the transfer function from the force to the response of the micro-vibration environment simulation platform is Gp, and the inverse model filter Gpinv is obtained by inverting the segment. The time domain signal x(n) of the designed spectrum standard is passed through the filter to obtain the actual micro-vibration excitation control signal U used on the exciter. active (n) so that the simulation platform exhibits the target response;
[0010] 5) The current feedforward control signal U ff Compared with the actual micro-vibration excitation control signal U active The signals are added to obtain the final control signal U output to the actuator. out ; Using the decoupling matrix G decouple The control signal U out The solution is applied to each actuator so that the output of each actuator will eventually act equivalently at the center of mass of the simulation platform. Finally, the combined force of all actuator outputs will realize the simulation of the micro-vibration environment.
[0011] In the present invention, in step 1), the elements of the passive vibration isolation unit are selected from any one or more of rubber pads, rubber springs or air springs, the foundation vibration sensor adopts any one of a displacement sensor, a velocity sensor or an acceleration sensor, and the actuator adopts an electromagnetic actuator.
[0012] In the present invention, in step 1), the actuators are arranged vertically, horizontally or longitudinally at the four corners or support positions of the platform.
[0013] In the present invention, in step 2) and step 4), the transfer function Gp from the force applied to the platform to the acceleration response of the platform is expressed as a second-order spring damping model.
[0014] In the present invention, in step 3), the VC level vibration standard is determined using 1 / 3 octave. According to the system's spectral resolution df and sampling frequency Fs, a complete spectrum standard X(f) corresponding to the 1 / 3 octave standard can be obtained by linear interpolation, where f = 0, 1, 2, ..., N-1, N is the number of points in the spectrum, and N = Fs / df.
[0015] In the present invention, in step 3), the spectrum inversion method is selected from any one of the trigonometric series method, the white noise filtering method, the quadratic function filtering method or the inverse Fourier transform method.
[0016] In the present invention, in step 2) and step 4), the transfer function Gp(s) from the force applied to the platform to the response of the platform is expressed as a second-order spring damping model; the response corresponds to an acceleration response, a displacement response, or a velocity response;
[0017] In the present invention, in step 5), the decoupling matrix G decouple The establishment of can be obtained by simply writing the actuator's position and force direction in the form of a matrix and then finding the inverse matrix.
[0018] Compared with the prior art, the present invention has the following advantages:
[0019] This invention utilizes passive vibration isolation units for platform support and utilizes feedforward control technology with a combination of ground-based vibration sensors and actuators to further suppress the effects of ground vibration, thereby achieving lower vibration levels. After converting the target vibration level into a spectral index and obtaining a time-domain excitation signal through inversion, the inverse model filter and decoupling matrix combine to achieve the target micro-vibration level on the platform by utilizing the output forces of actuators positioned around the platform or at its support locations.
[0020] The proposed precision VC standard micro-vibration environment simulation system based on foundation feedforward can further suppress the impact of foundation vibration, thereby providing a micro-vibration environment with lower vibration levels and establishing a unified vibration testing standard for equipment development and delivery. This invention is easy to implement and has universal applicability. BRIEF DESCRIPTION OF THE DRAWINGS
[0021] Figure 1 It is a schematic diagram of the composition framework of the present invention.
[0022] Figure 2 This is a schematic diagram of the VC vibration level and the corresponding spectrum standard used in Example 1 of the present invention.
[0023] Figure 3 This is a schematic diagram of the time domain excitation signal corresponding to the VC-D vibration level used in Example 1 of the present invention.
[0024] Figure 4 Schematic diagram of the micro-vibration simulation effect of the micro-vibration simulation experimental platform according to Example 1 of the present invention. DETAILED DESCRIPTION
[0025] The present invention will be described below with reference to specific embodiments.
[0026] As the sensitivity of precision equipment to vibration continues to increase, relevant testing standards are becoming increasingly stringent, and equipment manufacturers are in urgent need of a high-precision micro-vibration environment for testing. Common micro-vibration simulation systems are affected by foundation vibrations and it is difficult to achieve the high-precision micro-vibration environment required by ultra-precision equipment. For this reason, a precision VC standard micro-vibration environment test system based on foundation feedforward is proposed. It adopts a passive vibration isolation unit combined with a feedforward controller to suppress the influence of foundation vibrations, and uses active excitation to simulate the micro-vibration environment, which can achieve micro-vibration levels lower than the VC level of the ground, providing equipment manufacturers with a standardized micro-vibration environment, effectively solving the problem of inconsistent vibration environment requirements between equipment production and use, and avoiding the dilemma that the equipment meets the performance standards in the debugging site but cannot meet the technical indicators in the actual use environment, thereby significantly improving the reliability and environmental adaptability of the equipment. The present invention is based on the perspective of practical application needs, with clear ideas, easy implementation, and versatility and universality.
[0027] The present invention is a precise VC standard micro-vibration environment simulation system based on ground-based feedforward, such as Figure 1 As shown, the use of passive vibration isolation units combined with feedforward control further suppresses ground vibration while supporting the platform, thereby achieving lower micro-vibration levels. Furthermore, active excitation is used to simulate the micro-vibration environment, providing multiple levels of micro-vibration testing environments and resolving the issue of inconsistent environmental vibration during equipment testing.
[0028] Example 1
[0029] The present invention proposes a method for simulating a precise VC standard micro-vibration environment based on ground-based feedforward, comprising the following steps:
[0030] S1) The micro-vibration environment simulation platform utilizes a combined active and passive design architecture. Passive vibration isolation units serve as the platform's foundation, while ground vibration sensors are installed to sense ground vibrations. Actuators are installed on this foundation to output feedforward control forces to offset ground vibrations while also serving as active excitation sources for micro-vibration environment simulation.
[0031] S2) Design a feedforward controller G based on the system model ff , the foundation vibration signal S obtained by the foundation vibration sensor ground , calculate the control signal U ff ;
[0032] S3) Based on the VC vibration level standard, quantize it into a discrete spectrum X through a spectrum conversion algorithm, and use spectrum inversion technology to reconstruct a time domain vibration excitation signal x that conforms to the spectrum characteristics;
[0033] S4) Obtain an inverse model filter Gpinv according to the system model, and obtain the micro-vibration excitation control signal U through the filteractive ; The micro-vibration excitation signal U active and the feedforward control signal U ff After combining, the final control signal U out , using the actuator configured on the platform, the control signal U out Converted into the corresponding output force F.
[0034] Furthermore, in the above step S1), the vibration sensor can be any one of a displacement sensor, a velocity sensor or an acceleration sensor; the output direction of the actuator depends on the number of degrees of freedom that need to be simulated. If only micro-vibration of a single degree of freedom needs to be simulated, then the actuator with the output direction can be placed. The number of actuators is mainly determined by the required output size. When the test equipment is heavy and the vibration level to be simulated is high, it is preferred to place more. In addition, since the test equipment needs to be placed in the center of the platform, the actuators are usually installed around. For ease of installation, they can also be placed near the support position, so that they can form an integrated design with the support unit. A distributed layout is also possible. The influence of different positions is eliminated through the decoupling matrix, and ultimately the resultant force can be applied to the center.
[0035] In this example, step S1) is specifically as follows:
[0036] S1001) In this example, four rubber springs are selected as support elements and placed at the four corners of the marble platform to isolate ground vibrations. Accelerometers are selected as ground vibration sensors and installed on the platform's foundation. One vertical electromagnetic actuator and one transverse electromagnetic actuator are configured at each support position on the platform, for a total of eight electromagnetic actuators to simulate a six-degree-of-freedom microvibration environment. For ease of integrated design, the actuators and rubber springs are mounted on the same connector and then mounted on the platform.
[0037] Furthermore, the above step S2 is specifically as follows:
[0038] S2001) For the micro-vibration simulation platform in this example, the transfer function Gp(s) from the force applied to the platform to the platform's acceleration response can be expressed as a second-order spring-damper model, where s represents a complex variable and represents the frequency in the Laplace transform domain. The platform mass m, the rubber spring damping coefficient c, and the rubber spring stiffness coefficient k are inherent characteristics of the platform and are all known quantities. The transfer function is expressed as follows:
[0039] m=1740kg
[0040] c=1.09×10 5 Ns / m
[0041] k=1.011×10 7 Ns / m
[0042]
[0043] The frequency range of interest in the VC standard is 1-100Hz, so a second-order low-pass filter and a high-pass filter are designed to limit the feedforward action frequency. Since the foundation vibration sensor uses an acceleration sensor, in order to convert the sensed vibration into the corresponding offset control force, the designed feedforward controller G ff (s) is expressed as follows:
[0044]
[0045] ζ=0.707
[0046] ω0=2π×0.1rad / s
[0047] ω h =2π×1rad / s
[0048] ω l =2π×100rad / s
[0049] In this example, an accelerometer is selected as the ground vibration sensor. The sensor collects a real-time signal, Sground. After digitizing the feedforward controller Gff(s) designed above, the sensor signal Sground passes through the feedforward controller to generate a real-time signal, Uff, for feedforward control.
[0050] In this example, the denominator cs+k in the system model is the feedforward force caused by the ground displacement; for the transfer function Gp(s) of the acceleration response in this example, its numerator is s 2 In other cases, if the transfer function is velocity response, the numerator is s, and if the transfer function is displacement response, the numerator is 1. The denominator of the corresponding feedforward controller is also related to the sensor type. The denominator of the acceleration is (s+ω0) 2 , the denominator of velocity is (s+ω0), and the displacement is 1; however, for low-frequency and micro-vibration scenarios, extremely high requirements are placed on displacement sensors, and acceleration or velocity is usually used.
[0051] Furthermore, the above step S3) is specifically as follows:
[0052] S3001) Considering the hardware limitations of this example, a spectrum resolution of df = 0.01 Hz and a sampling frequency of Fs = 5000 Hz are used in this example. Since the vibration level standard VC level is established by 1 / 3 octave bands, linear interpolation is required to obtain a complete spectrum. Finally, the spectrum standard X corresponding to the vibration levels of VC-A, VC-B, VC-C, and VC-D is obtained. A(f), X B (f), X C (f) and X D (f), such as Figure 2 As shown, where k = 0, 1, 2, ..., N-1, N is the number of points in the spectrum, N = Fs / df = 500000;
[0053] S3002) Taking the VC-D level micro-vibration simulation requirements as an example, based on the measured vibration spectrum X D (f) The spectrum is reconstructed using the inverse Fourier transform method, and its mathematical expression is:
[0054]
[0055] The time domain signal x that meets the spectrum standard can be obtained D (n), such as Figure 3 As shown, where n = 0, 1, 2,…, 499999.
[0056] Furthermore, the above step S4) is specifically as follows:
[0057] S4001) In order to make the platform exhibit the target acceleration response, it is necessary to consider the influence of the transfer function Gp(s) from the force to the acceleration response of the experimental platform. Therefore, the inverse model filter Gpinv(s) of Gp(s) is designed. The expression is as follows:
[0058]
[0059] After digitizing the filter, the designed spectrum standard time domain signal x D (n) After filtering, the actual force time domain signal U is obtained active (n), where n = 0, 1, 2, ..., 499999. D (n) is the ideal excitation signal, which does not consider the platform characteristics, U active (n) is the excitation signal used on the real exciter, so it is called the actual micro-vibration excitation control signal.
[0060] S4002) In this example, 8 electromagnetic actuators are used as actuators. Since they are installed at different positions on the experimental platform, there is a deviation between the actuator force position and the center of mass of the platform. It is necessary to use the decoupling matrix G decouple Distribute the output of each actuator, and finally act equivalently on the center of mass of the platform. The obtained control signal sequence U active (n) is added to the real-time feedforward signal Uff to obtain the real-time control signal U out , is solved on each actuator through the decoupling matrix, so that the final resultant force of all actuator output forces is F.
[0061] Finally, the designed force is applied to the platform to simulate the micro-vibration environment of the specified VC standard. The vibration test results of the micro-vibration simulation platform designed according to the VC-A, VC-B, VC-C and VC-D vibration levels are verified by third-party sensors. Figure 4 As shown in the figure, the vibration spectrum on the experimental platform closely matches the ideal VC vibration level standard spectrum, simulating the target vibration level. Furthermore, due to the addition of foundation feedforward to suppress the influence of ground vibration, it can simulate even lower VC-D micro-vibration levels, thus meeting the testing requirements of precision equipment.
Claims
1. A precision VC standard micro-vibration environment simulation method based on ground-based feedforward, characterized in that: The following steps are involved: 1) Construction of a micro-vibration environment simulation platform: The micro-vibration environment simulation platform adopts an active-passive combined design architecture, which includes a passive vibration isolation unit, a platform, a foundation vibration sensor, and an actuator. The passive vibration isolation unit serves as the foundation of the platform support, and the foundation vibration sensor is used to sense foundation vibration. The actuator is used to output feedforward control force and serve as an active excitation source for micro-vibration environment simulation. 2) Assume that the transfer function from the force to the response of the micro-vibration environment simulation platform is Gp. According to the force part of the transfer function combined with the bandpass filter, the feedforward controller G is obtained. ff ; The foundation vibration signal S obtained by the foundation vibration sensor ground Through the feedforward controller G ff , get the real-time feedforward control signal U ff ; 3) Based on the VC vibration level standard, the spectrum is quantized into a discrete spectrum through the spectrum conversion method, and the spectrum inversion method is used to reconstruct the time domain vibration excitation signal x(n) that conforms to the spectrum characteristics, where n = 0, 1, 2, ..., N-1, where N is the number of points in the spectrum; 4) Assume that the transfer function from the force to the response of the micro-vibration environment simulation platform is Gp, and the inverse model filter Gpinv is obtained by inverting the segment. The time domain signal x(n) of the designed spectrum standard is passed through the filter to obtain the actual micro-vibration excitation control signal U active (n) so that the simulation platform exhibits the target response; 5) The current feedforward control signal U ff Compared with the actual micro-vibration excitation control signal U active The signals are added to obtain the final control signal U output to the actuator. out ; Using the decoupling matrix G decouple The control signal U out The solution is applied to each actuator so that the output of each actuator will eventually act equivalently at the center of mass of the simulation platform. Finally, the combined force of all actuator outputs will realize the simulation of the micro-vibration environment.
2. The method for simulating precise VC standard micro-vibration environment based on ground-based feedforward according to claim 1, characterized in that: In step 1), the components of the passive vibration isolation unit are selected from any one or more of rubber pads, rubber springs or air springs, the foundation vibration sensor adopts any one of a displacement sensor, a velocity sensor or an acceleration sensor, and the actuator adopts an electromagnetic actuator.
3. The method for simulating precise VC standard micro-vibration environment based on ground-based feedforward according to claim 1, characterized in that: In step 1), the actuators are arranged vertically, horizontally or longitudinally at the four corners or support positions of the platform.
4. The method for simulating precise VC standard micro-vibration environment based on ground-based feedforward according to claim 1, characterized in that: In step 2) and step 4), the transfer function Gp from the force applied to the platform to the response of the platform is expressed as a second-order spring damping model; the response corresponds to an acceleration response, a displacement response, or a velocity response.
5. The method for simulating precise VC standard micro-vibration environment based on ground-based feedforward according to claim 1, characterized in that: In step 3), the VC level vibration standard is determined using 1 / 3 octave. Based on the system's spectral resolution df and sampling frequency Fs, linear interpolation can be used to obtain the complete spectrum standard X(f) corresponding to the 1 / 3 octave standard, where f = 0, 1, 2, ..., N-1, N is the number of points in the spectrum, and N = Fs / df.
6. The method for simulating precise VC standard micro-vibration environment based on ground-based feedforward according to claim 1, characterized in that: In step 3), the spectrum inversion method is selected from any one of a trigonometric series method, a white noise filtering method, a quadratic function filtering method or an inverse Fourier transform method.