An active shock mitigation method and system

Abstract

This invention relates to the fields of safe construction and seismic isolation technology, and in particular to an active vibration reduction method and system. The invention first places a vibration generator between the seismic source location and the target protection area; the vibration generator is then driven to produce a canceling wave with a phase opposite to the seismic source vibration wave, thereby canceling part or all of the amplitude of the seismic source vibration wave transmitted to the target protection area. This invention overcomes the problem that strong vibration construction can easily cause vibration damage to surrounding buildings, and achieves precise vibration reduction by employing active seismic source cancellation technology.

Description

Technical Field

[0001] This invention relates to the fields of safe construction and vibration reduction and isolation technology, and in particular to an active vibration reduction method and system. Background Technology

[0002] Against the backdrop of the ongoing urban renewal strategy, the renovation of old urban areas and the upgrading of core area functions have become important vehicles for high-quality urban development. Construction projects, as a key component of urban renewal, face multiple stringent challenges in densely built-up areas. During the urban renewal process, through the investigation of existing civil defense projects and the application of key technologies for safety hazard management, some civil defense projects have been gradually identified as having safety hazards such as structural aging and insufficient load-bearing capacity. Meanwhile, environmental disturbances generated by building pile foundation construction are becoming a significant source of risk exacerbating these hazards.

[0003] As the core load-bearing component that transfers the superstructure load to the ground, pile foundations are a crucial part of building construction. Current mainstream pile foundation construction techniques, such as hammering and static pressure methods, not only generate strong vibration waves and soil displacement effects during operation, but also produce significant construction noise and energy consumption, contradicting the development requirements of energy conservation, carbon reduction, and green construction in the building industry. This type of vibration energy propagates widely through the soil. When the vibration intensity exceeds the structural tolerance threshold of adjacent existing buildings, it can easily cause shallow cracks or even through-cracks in the walls, plaster layer peeling off, and uneven settlement of the building foundation. For existing civil defense projects, the arches and arch feet are even more sensitive to vibration. Construction vibration may cause cracking of the lining structure and waterproofing failure, directly affecting the effectiveness of safety hazard mitigation after the survey of existing civil defense projects, threatening the safety of surrounding residents, the stable operation of existing urban infrastructure, and the wartime protective function of civil defense projects.

[0004] Traditional passive vibration isolation measures, such as vibration isolation trenches and rubber pads, which are commonly used in the engineering field at present, attempt to reduce the impact of construction vibration through physical isolation and buffering. However, in the context of urban renewal and dense building areas, they are not suitable for the technical requirements of existing civil defense engineering safety management, nor can they meet the development needs of energy conservation and noise reduction, and have significant limitations. First, in urban renewal areas, the buildings are close together, and underground pipe networks intersect with existing civil defense projects, resulting in extremely limited available construction space. Vibration isolation trenches are often difficult to excavate to the ideal depth and width, and the excavation process may disturb the surrounding original soil and the retaining structure of civil defense projects, exacerbating foundation settlement and safety hazards of civil defense projects. Second, the vibration isolation effect of rubber pads is unstable and easily affected by factors such as soil moisture content and geological strata changes, making it unable to continuously block vibration transmission. In addition, rubber materials are prone to aging and their vibration isolation performance deteriorates rapidly. Furthermore, traditional vibration isolation measures do not take into account energy conservation and consumption reduction design, failing to reduce energy consumption and noise pollution during construction. Third, traditional measures have not been coordinated with the key technologies for the general survey and safety hazard management of existing civil defense projects, and have not been able to develop specific vibration isolation schemes for the vibration tolerance threshold of civil defense projects, making it difficult to ensure the structural safety of civil defense projects after treatment. These shortcomings make traditional vibration isolation measures unsuitable for the stringent requirements of pile foundation construction in densely built-up areas under the background of urban renewal. They cannot fundamentally solve the adverse effects of construction vibration on surrounding buildings and existing civil defense projects, nor can they meet the green construction needs of energy saving and noise reduction. Summary of the Invention

[0005] In order to overcome the problem that strong vibration construction in the prior art can easily cause vibration damage to surrounding buildings, this invention proposes an active vibration reduction method that uses active vibration source cancellation technology to achieve precise vibration reduction.

[0006] The present invention proposes an active vibration reduction method, which first sets up a vibration generator between the source location and the target protection area; drives the vibration generator to generate a canceling wave with the opposite phase to the source vibration wave, so as to cancel out part or all of the amplitude of the source vibration wave transmitted to the target protection area.

[0007] Preferably, multiple vibration generators are installed between the earthquake source location and the target protection area along the direction of earthquake vibration wave transmission.

[0008] Preferably, the amplitude of the canceling wave emitted by each vibration generator decreases sequentially from the source location to the target protection area.

[0009] The present invention proposes a control system for implementing the aforementioned building construction vibration reduction method, comprising: a vibration acquisition module, a control module, and a reverse excitation module; The vibration acquisition module is used to monitor the vibration signal of the seismic source and the state of the vibration wave along the propagation path in real time; the reverse excitation module is used to transmit the antiphase vibration wave detected by the vibration acquisition module; the control module is connected to the vibration acquisition module and the reverse excitation module respectively, and generates control commands based on the analysis results of the detected vibration wave of the vibration acquisition module, which are used to drive the reverse excitation module to generate the reverse excitation module.

[0010] Preferably, the vibration acquisition module includes multiple vibration sensors, and the reverse excitation module includes multiple exciters; in the direction of vibration wave transmission from the source location to the target protection area, the vibration sensors and exciters are arranged alternately, and the control module generates control commands for the exciters adjacent to and following the vibration sensors based on the detection results of the vibration sensors.

[0011] Preferably, the control module includes: a signal acquisition and conditioning unit, an excitation drive unit, and a motherboard unit; The signal acquisition and conditioning unit is used to condition the vibration signals acquired by the vibration acquisition module; The motherboard unit is used to analyze the conditioned signal output by the signal acquisition and conditioning unit and calculate the control instructions for the reverse excitation module; The excitation drive unit converts the control commands output by the motherboard unit into drive signals for the reverse excitation module and sends them to the reverse excitation module.

[0012] Preferably, the signal acquisition and conditioning unit includes a preamplifier circuit, a filter circuit, a detector circuit, and a shaping circuit connected in sequence; the excitation drive unit includes a pulse modulation circuit (PWM) and a power amplifier circuit.

[0013] Preferably, the vibration acquisition module uses a three-component vibration sensor, and the reverse excitation module uses a three-component exciter.

[0014] Preferably, the control module further includes a power management unit, a storage unit, a communication unit, and an expandable unit, wherein the expandable unit is used to provide a function expansion interface.

[0015] The advantages of this invention are: (1) This invention proposes an active vibration reduction method, which breaks through the passive vibration isolation thinking and proposes an active vibration source cancellation technology of "real-time monitoring-reverse generation-dynamic control". Through the spatiotemporal superposition characteristics of vibration waves, a "vibration propagation gap" is formed in front of the protected area to achieve precise vibration reduction.

[0016] (2) By setting up multiple vibration generators, the present invention realizes multi-level vibration reduction in the vibration reduction direction, which is conducive to flexible control of the vibration reduction effect and is applicable to most vibration reduction scenarios.

[0017] (3) The control system proposed in this invention uses sensors and exciters to control the emitted wave of the exciter in real time according to the detected vibration wave, thereby realizing automated wave cancellation. Attached Figure Description

[0018] Figure 1 This is based on the principle of multiple reductions of anti-phase vibration waves; Figure 2 This is a schematic diagram of an active damping system; Figure 3 This is a flowchart of a building construction vibration reduction method; Figure 4 This is a schematic diagram of the system modules; Figure 5 This describes the system's on-site layout in the embodiment. Figure 6 The vibration sensor in the embodiment monitors vibration waves; Figure 7 The amplitude of the vibration wave after multiple reductions in the embodiment; Figure 8 This is a signal comparison diagram from the embodiment. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0020] Unit Explanation: In this application, the units for each physical parameter are as follows: Amplitude, in centimeters; Time, in seconds; angular frequency of vibration, in rad / s; phase of the wave, in rad. According to the superposition principle of waves, when two vibration waves are staggered by a certain phase, their amplitudes can cancel each other out, thus achieving vibration reduction. For vibration waves during pile foundation construction, when the geological conditions of the pile foundation (source location) and the surrounding building complex (target protection area) are the same, the vibrations generated at the monitoring points by different sources are the same or similar. The construction vibration effect is as follows:

[0021] In the formula, A(t) is the amplitude at the monitoring point; A i (t) represents the amplitude generated by the i-th seismic source at the monitoring point; t is the time; i 1,2,3,...,n, where n is the total number of earthquake sources.

[0022] If we consider the seismic waves during pile foundation construction as simple harmonic waves, then:

[0023] In the formula, A i (t) represents the amplitude generated by the i-th seismic source at the monitoring point; ω represents the angular frequency of the vibration. t represents the phase of the wave; t represents time.

[0024] Considering only the superposition of two earthquake sources:

[0025] In the formula, A(t) is the combined amplitude of the simple harmonic wave. 1 represents the vibration phase generated by the first earthquake source; 2 represents the vibration phase generated by the second seismic source.

[0026] To ensure that the amplitude of the superimposed vibration is less than the amplitude of the pile foundation construction, we have:

[0027]

[0028] By superimposing multiple small-amplitude, opposite-phase vibration waves, the vibration impact generated during pile foundation construction is reduced. The principle is as follows: Figure 1 As shown.

[0029] The embodiment provided Figure 2 The construction vibration reduction method shown employs an active cancellation mechanism for construction vibration waves based on a control logic of "real-time monitoring - reverse generation - dynamic adjustment"; and utilizes... Figure 3 , Figure 4 The system shown includes a vibration acquisition module, a control module, and a reverse excitation module.

[0030] The vibration acquisition module is used to monitor the vibration signals generated by the pile driver and the vibration wave status along the propagation path in real time. The vibration acquisition module can be implemented using a three-component vibration sensor.

[0031] Specifically, the vibration acquisition module includes multiple three-component vibration sensors that act as vibration generators, forming a three-component vibration sensor array as the system's sensing input source. The vibration acquisition module acquires vibration acceleration / velocity / displacement signals of the controlled structure in the X / Y / Z directions in real time, converting the mechanical vibration into weak electrical signals at the mV level, providing raw feedback data for the system.

[0032] The reverse excitation module employs a three-component exciter array, comprising multiple three-component exciters arranged in a specific configuration. These three-component exciters emit antiphase vibration waves that are detected by the three-component vibration sensor, thereby interfering with and canceling out the original vibration detected by the sensor.

[0033] In practical implementation, a drive unit can be set at the front end of the three-component vibrator. The three-component vibrator serves as the system's execution output unit. It receives the high-power signal from the drive unit and outputs a force that is opposite in direction and matches the amplitude of the structural vibration, thereby counteracting the vibration of the controlled structure and achieving active vibration reduction.

[0034] The control module is connected to the vibration acquisition module and the reverse excitation module respectively. It acquires the vibration signal collected by the vibration acquisition module, analyzes the frequency, amplitude and phase of the vibration wave and other attributes, generates a vibration wave control command with specified amplitude and phase and sends it to the reverse excitation module, thereby driving the reverse excitation module to generate a force with the opposite direction and matching amplitude to the structural vibration.

[0035] The control module, acting as the system's synchronization and scheduling hub, is used to achieve unified scheduling of vibration acquisition and drive links. Specifically, the system employs a multi-channel approach. The vibration acquisition module on the acquisition side synchronously selects, controls the timing of, and switches channels for N sensor signals (i.e., structural vibrations acquired by N three-component vibration sensors), ensuring synchronous sampling of multi-channel signals and avoiding timing errors. The reverse excitation module on the drive side receives the master control commands from the control module and synchronously drives and distributes the N actuators (i.e., three-component vibrators), achieving coordinated output from the multi-channel actuators.

[0036] The control module in this embodiment includes: a signal acquisition and conditioning unit, an excitation drive unit, and a motherboard unit.

[0037] The signal acquisition and conditioning unit, as the core of signal preprocessing in the acquisition link, conditions the weak signal output by the sensor (i.e., the three-component vibration sensor) into a standard signal that meets the requirements of the main control input.

[0038] The signal acquisition and conditioning unit comprises a preamplifier circuit, a filter circuit, a detector circuit, and a shaping circuit connected in sequence. The weak mV-level electrical signals from each sensor (three-component vibration sensor) in the vibration acquisition module are first amplified by the preamplifier circuit with high gain and low noise to match the input range of the main control ADC (typically ±5V / ±10V). The amplified signal output from the preamplifier circuit is filtered by the filter circuit and then enters the detector circuit to extract the amplitude / envelope information of the vibration signal, adapting it to the time-domain / frequency-domain vibration analysis and control algorithm requirements of the system. The signal extracted by the detector circuit undergoes level conversion, noise reduction, and waveform shaping by the shaping circuit to obtain a stable digital / analog signal, which is then sent to the active mainboard unit.

[0039] The core of the filtering circuit is an anti-aliasing low-pass filter, which filters out high-frequency noise and interference signals, ensures that the sampled signal satisfies the Nyquist sampling theorem, and avoids spectral distortion.

[0040] The motherboard unit includes a CPLD controller and an embedded MCU.

[0041] As the core of the system's computation and management, the embedded MCU is responsible for algorithm execution and global scheduling, and mainly supports the following functions: a. Run active vibration reduction control algorithms (such as PID, adaptive control, LMS adaptive filtering, feedforward control, etc.) and calculate and generate reverse control commands based on the vibration signals collected by the sensors; b. System status management: such as fault diagnosis, parameter tuning, data storage, communication interaction, power management, etc. c. It can work in high-speed collaboration with CPLD to issue control commands, receive collected data, and realize the logical scheduling of closed-loop control.

[0042] As the high-speed logic hub of the system, the CPLD controller compensates for the real-time limitations of the MCU, handling hardware timing and logic control. The CPLD controller primarily supports the following functions: a. Timing control of the signal acquisition and conditioning unit / excitation drive unit to achieve synchronous sampling and synchronous driving of multi-channel signals; b. Logic control of the signal acquisition and conditioning unit to realize the timing scheduling of filtering, detection and shaping; c. High-speed interaction with embedded MCU to achieve coordination between algorithm instructions and hardware logic, ensuring system real-time response at the μs level.

[0043] The excitation drive unit is the core of the execution link's power amplification, converting the weak control signals output by the motherboard unit into high-power signals that can drive the actuators (three-class exciters).

[0044] The excitation drive unit includes a pulse modulation circuit (PWM) and a power amplifier circuit.

[0045] The pulse modulation circuit (PWM) acquires the digital control commands output by the MCU and converts them into high-frequency pulse modulation signals to match the input requirements of the power amplifier circuit. The power amplifier circuit amplifies the voltage / current of the PWM signal output by the pulse modulation circuit and outputs sufficient power (high current / high voltage) to drive the actuator to output a reverse canceling force.

[0046] The control module also includes a power management unit, a storage unit, a communication unit, and an expansion unit.

[0047] The power management unit acts as the system's energy hub, providing a stable and reliable power supply to the entire system. It supports both power adapters (fixed AC power) and lithium batteries (portable / power-off backup), and can automatically switch between power supply modes.

[0048] The storage unit is used to store detection data, system configuration parameters, algorithm programs, and other information, enabling local caching and backtracking of data.

[0049] The communication unit serves as the system's interactive interface, establishing connections with remote terminals (PCs, data centers, handheld devices, etc.) to upload detection data, receive remote control commands, and support data sharing and remote operation and maintenance.

[0050] The expandable unit serves as the system's functional expansion interface, adapting to local human-computer interaction and peripheral device expansion needs. The expandable unit supports the following device connections: 1) Buttons: Enable manual operations such as local parameter settings, system start / stop, and mode switching; 2) Display screen: Real-time display of vibration data, system status, and vibration reduction effect; supports local monitoring. 3) I / O ports: Expand external sensors, actuators, alarm devices, etc., to adapt to different application scenarios; 4) Alarm: When the system malfunctions, vibration exceeds the limit, or power supply is abnormal, an audible and visual alarm will be issued to ensure system safety.

[0051] This embodiment proposes a method for vibration reduction during building construction, which includes the following steps.

[0052] Step 1: Deploy the exciter array: Between the building protection area and the pile foundation construction area, deploy n three-component exciters along the vibration wave propagation direction, denoted as N1, N2, ..., N... n .

[0053] The number and location of vibrators can be determined based on the location of the protected building area and the vibration reduction target. A possible arrangement is a combination of small amplitude and numerous vibrators (a larger number of vibrators, each with a smaller amplitude); a combination of large amplitude and a smaller number of vibrators (a smaller number of vibrators, each with a larger amplitude); or a combination of large amplitude and small amplitude, where vibrators closer to the construction piles have larger amplitudes and those farther away have smaller amplitudes. The arrangement can be flexibly applied based on site conditions and the desired vibration reduction target. Step 2: Deploy real-time vibration monitoring sensors: Install m sensors at the construction pile foundation, between vibrators, and within the building area to collect vibration data from the seismic source in real time. The sensors can be buried 1-2m deep to avoid surface interference. For example... Figure 5 As shown, sensor M1 is installed at the construction pile foundation, sensor M2 is installed between the first vibrator N1 and the second vibrator N2, sensor M3 is installed between the second vibrator N2 and the third vibrator N3, and so on. Step 3: Waveform Data Analysis and Opposite-Phase Vibration Generation: Vibration signals are monitored in real time. During pile foundation construction, the pile foundation vibration wave propagates along the surrounding soil layers, first reaching the nearest sensor M1. Sensor M1 feeds back the monitored vibration signal to the system. The system calculates and analyzes key elements such as the vibration wave waveform, propagation velocity, and amplitude generated by the pile foundation, and calculates the time T1 it takes for the vibration wave to reach the exciter N1. The system then controls the main computer to issue a command, and at time T1, the exciter N1 emits a vibration signal with the same waveform, amplitude (which can be specified, and should be less than or equal to the vibration amplitude monitored by the sensor), and opposite phase to the vibration wave, performing the first reduction. According to the principle of wave superposition, when two vibration waves are out of phase, their amplitudes can cancel each other out. In practice, considering various interferences and site conditions, multiple reductions are required to achieve vibration reduction. After the vibration wave is reduced once, it propagates to sensor M2. Sensor M2 feeds back the monitored vibration signal to the control system. The control system calculates and analyzes the key elements of the vibration wave, such as waveform, propagation speed, and amplitude. Based on this, it calculates the time T2 when the vibration wave after the first reduction propagates to exciter N2. The control computer issues a command, and exciter N2 emits a vibration signal at time T2 that has the same waveform, the same amplitude, and the opposite phase as the vibration wave after the first reduction, to perform the second reduction. Repeat the above steps continuously. As needed, the vibration waves are reduced sequentially. The repeatedly weakened pile foundation vibration forms a vibration blind zone in the building complex area (i.e., the target protection area), where the amplitude is smaller than the original amplitude.

[0054] The above system and method are verified in conjunction with specific embodiments below.

[0055] A specific implementation case, such as Figure 6 As shown, there is a building complex 100m east of the pile foundation construction site. Two vibrators, A and B, are installed at 30m and 50m respectively on the pile foundation. Multiple sensors are deployed within the building protection area to monitor the vibration in different areas in real time. When the vibration waveform of the pile foundation is detected, the propagation speed of the vibration wave is calculated to be 2000m / s, and the relative amplitude is 0.25. Vibrator A emits a vibration wave with the same waveform as the pile foundation but opposite phase at 50ms, with a relative amplitude of 0.25. Vibrator B emits a vibration wave with the same waveform as the pile foundation but opposite phase at 80ms, with a relative amplitude of 0.15.

[0056] like Figure 7 As shown, the vibration waves of the pile foundation are canceled out by the vibration waves emitted by the vibrator, resulting in a weakened amplitude. The repeatedly weakened pile foundation vibrations create a vibration blind zone in the building complex area, where the amplitude is smaller than the original amplitude.

[0057] Compare the vibrations within the building area, such as Figure 8As shown, the green signal is the original signal without vibration cancellation emitted by the exciter, with a peak relative amplitude of 0.25, and the red signal is the signal with vibration cancellation emitted by the exciter, with a peak relative amplitude of 0.1. It can be seen that the vibration peak amplitude is reduced by 60%, demonstrating the effectiveness of the present invention.

[0058] Of course, those skilled in the art will recognize that the present invention is not limited to the details of the exemplary embodiments described above, but also includes the same or similar structures that can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0059] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

[0060] The technologies, shapes, and structures not described in detail in this invention are all known technologies.

Claims

1. An active vibration damping method, characterized in that, First, a vibration generator is installed between the epicenter and the target protection area; the vibration generator is driven to produce a canceling wave that is out of phase with the epicenter vibration wave, so as to cancel out part or all of the amplitude of the epicenter vibration wave transmitted to the target protection area.

2. The construction vibration reduction method as described in claim 1, characterized in that, Multiple vibration generators are installed between the earthquake source location and the target protection area, along the direction of the earthquake vibration wave transmission.

3. The construction vibration reduction method as described in claim 2, characterized in that, From the epicenter location to the target protection area, the amplitude of the canceling waves emitted by each vibration generator decreases sequentially.

4. A control system for implementing the building construction vibration reduction method as described in any one of claims 1-3, characterized in that, include: Vibration acquisition module, control module, and reverse excitation module; The vibration acquisition module is used to monitor the vibration signal of the seismic source and the state of the vibration wave along the propagation path in real time; the reverse excitation module is used to transmit the antiphase vibration wave detected by the vibration acquisition module; the control module is connected to the vibration acquisition module and the reverse excitation module respectively, and generates control commands based on the analysis results of the detected vibration wave of the vibration acquisition module, which are used to drive the reverse excitation module to generate the reverse excitation module.

5. The control system as described in claim 4, characterized in that, The vibration acquisition module includes multiple vibration sensors, and the reverse excitation module includes multiple exciters. In the direction of vibration wave transmission from the source location to the target protection area, the vibration sensors and exciters are arranged alternately. The control module generates control commands for the exciters that are adjacent to and follow the vibration sensors based on the detection results of the vibration sensors.

6. The control system as described in claim 5, characterized in that, The control module includes: a signal acquisition and conditioning unit, an excitation drive unit, and a mainboard unit; The signal acquisition and conditioning unit is used to condition the vibration signals acquired by the vibration acquisition module; The motherboard unit is used to analyze the conditioned signal output by the signal acquisition and conditioning unit and calculate the control instructions for the reverse excitation module; The excitation drive unit converts the control commands output by the motherboard unit into drive signals for the reverse excitation module and sends them to the reverse excitation module.

7. The control system as described in claim 6, characterized in that, The signal acquisition and conditioning unit includes a preamplifier circuit, a filter circuit, a detector circuit, and a shaping circuit connected in sequence; the excitation drive unit includes a pulse modulation circuit (PWM) and a power amplifier circuit.

8. The control system as described in claim 4, characterized in that, The vibration acquisition module uses a three-component vibration sensor, and the reverse excitation module uses a three-component exciter.

9. The control system as described in claim 4, characterized in that, The control module also includes a power management unit, a storage unit, a communication unit, and an expansion unit, which provides an interface for expanding functionality.

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