Marine main engine active vibration reduction method and device based on dual-threshold discrimination

Abstract

The invention provides an active vibration reduction method and device for a marine main engine based on dual-threshold discrimination, and the method comprises the steps: collecting a vibration signal of the marine main engine in real time, and converting the vibration signal into an electric signal; the electric signal is a voltage signal or a charge signal; performing analog-to-digital conversion and digital band-pass filtering processing on the electric signal, and separating out a vibration frequency band of host characteristics; based on the vibration frequency band, a double-threshold hysteresis judgment mechanism is adopted, and a vibration reduction mode for conducting vibration reduction on the marine main engine is determined; the vibration reduction mode comprises a passive vibration reduction mode and an active vibration reduction mode; when the active vibration reduction mode is started, the value of the dynamic reverse acting force opposite to the host vibration in phase is determined, and the host vibration is actively counteracted. According to the invention, the operation stability and safety of the marine main engine are obviously improved, and the problem that active vibration reduction is difficult to carry out under complex working conditions in the prior art is solved.

Description

Technical Field

[0001] This invention relates to the field of marine engineering technology, and in particular to a method and device for active vibration reduction of marine main engines based on dual threshold discrimination. Background Technology

[0002] Ships typically use high-power, low-speed diesel engines for main propulsion. Due to their long stroke and large reciprocating mass, these engines generate enormous periodic lateral thrust during operation. This lateral force excites complex transverse vibrations in the engine hull, primarily manifesting as H-mode and X-mode vibrations. Without effective control, these severe transverse vibrations can be transmitted to the hull structure through the double bottom, easily triggering harmful resonances in the superstructure, leading to malfunctions in bridge equipment and instruments, severely impacting the crew's working environment and living comfort. Prolonged high-amplitude vibrations can even cause structural damage such as broken engine tie rods and loose base bolts, jeopardizing the ship's navigational safety.

[0003] Currently, passive support systems are mainly used in engineering to suppress the lateral vibration of the main engine. Common types include friction plate supports and hydraulic supports. Friction supports utilize friction damping to dissipate vibration energy, but their damping force is greatly affected by the preload and the coefficient of friction. Furthermore, the friction pairs wear down over time, leading to increased clearance and a decline in vibration reduction efficiency over time, resulting in high maintenance costs. While hydraulic supports can provide greater stiffness and shift the main engine frequency out of the resonance zone, they are essentially still passive control systems, and their stiffness and damping parameters are difficult to change once set.

[0004] However, in order to meet environmental regulations such as EEDI, modern ships often need to operate under non-design conditions, resulting in a wider range of main engine excitation frequencies. Once the main engine's excitation frequency falls into the natural frequency range of the hull structure during speed changes, existing passive support systems often fail to provide optimal vibration reduction because they cannot adjust parameters in real time, and may even produce negative amplification effects at certain frequencies.

[0005] There is currently no effective solution to the problem that existing technologies are unable to perform active vibration reduction under complex working conditions. Summary of the Invention

[0006] This invention provides a method and apparatus for active vibration reduction of ship main engines based on dual threshold discrimination, which solves the shortcomings of existing technologies in performing active vibration reduction under complex working conditions.

[0007] This invention provides a method for active vibration reduction of ship main engines based on dual threshold discrimination, comprising: The vibration signal of the ship's main engine is acquired in real time and converted into an electrical signal; the electrical signal is a voltage signal or a charge signal. The electrical signal is subjected to analog-to-digital conversion and digital bandpass filtering to separate the vibration frequency band characteristic of the host. Based on the vibration frequency band, a dual-threshold hysteresis discrimination mechanism is used to determine the vibration reduction mode for the ship's main engine; the vibration reduction mode includes a passive vibration reduction mode and an active vibration reduction mode. When the active vibration reduction mode is activated, the value of the dynamic counterforce that is out of phase with the vibration of the host machine is determined, and the host machine vibration is actively counteracted.

[0008] According to the present invention, a method for active vibration reduction of a ship's main engine based on dual threshold discrimination is provided, which performs analog-to-digital conversion and digital bandpass filtering on the electrical signal to separate the vibration frequency band characteristic of the main engine, including: The electrical signal is converted into a high-precision digital signal using Delta-Sigma analog-to-digital conversion logic, differential integral modulation, and noise shaping techniques. Based on a linear time-invariant system, the vibration frequency band of the host machine is separated by a digital bandpass filter; the linearity of the linear time-invariant system satisfies superposition and scalarity.

[0009] According to the active vibration reduction method for ship main engines based on dual threshold discrimination provided by the present invention, the following frequency band separation logic is executed during digital bandpass filtering: The high-pass filter removes extremely low-frequency interference, while the low-pass filter removes high-frequency noise.

[0010] According to the present invention, a method for active vibration reduction of ship main engines based on dual-threshold discrimination is provided, wherein the dual-threshold hysteresis discrimination mechanism is as follows: When the vibration intensity is within the stop threshold, the passive vibration reduction mode is executed; When the vibration intensity exceeds the start-up threshold, the active vibration reduction mode is executed; the active vibration reduction mode is implemented using a composite architecture of PID control algorithm based on feedforward compensation and FxLMS algorithm.

[0011] The present invention provides a method for active vibration reduction of ship main engines based on dual threshold discrimination, which is based on a PID control algorithm with feedforward compensation, including feedforward control and feedback control; The feedforward control is: determining the required compensation amount based on the known characteristics of the system input signal or external disturbance; The feedback control is to adjust the system error through proportional, integral, and derivative actions.

[0012] According to the present invention, a method for active vibration reduction of a ship's main engine based on dual-threshold discrimination, after determining the value of the dynamic counterforce that is out of phase with the main engine vibration, includes: The dynamic reverse force is converted into a digital control sequence through scaling and zero-position offset processing; Using Delta-Sigma( The modulation algorithm processes the digital control sequence to obtain an analog voltage signal, which is then sent to the hydraulic valve of the ship's main engine.

[0013] According to the present invention, a method for active vibration reduction of a ship's main engine based on dual threshold discrimination is provided to actively counteract main engine vibration, comprising: The high-pressure oil flow of the hydraulic actuator of the ship's main engine is adjusted according to the analog voltage signal to establish a dynamic pressure difference on both sides of the piston; Driven by the pressure difference, the piston rod of the hydraulic actuator generates an active counteracting force that is equal in magnitude and opposite in direction to the vibration force of the ship's main engine, thereby counteracting the vibration of the main engine.

[0014] According to the present invention, a method for active vibration reduction of a ship's main engine based on dual threshold discrimination is provided. When the system power terminal or chip of the ship's main engine fails and cannot output a signal, it enters a passive vibration reduction mode.

[0015] Secondly, the present invention also provides a ship main engine active vibration damping device based on dual threshold discrimination, which is installed between the ship main engine and the engine room sidewall via a mounting base, characterized in that it comprises: The sensor system is used to collect vibration signals, collect vibration signals of the ship's main engine in real time, and convert the vibration signals into electrical signals; An integrated controller system is used to perform analog-to-digital conversion and digital bandpass filtering on the electrical signal to separate the vibration frequency band of the main engine, and to determine the vibration reduction mode for the ship's main engine based on the vibration frequency band using a dual-threshold hysteresis discrimination mechanism. Vibration damping system is used to actively counteract the vibration of the host machine.

[0016] According to the present invention, a ship main engine active vibration reduction device based on dual threshold discrimination is provided, wherein the sensor system includes an acceleration sensor and a data transmission line; The integrated control system includes an integrated controller, a data storage and processing unit, a numerical control unit, and a power module; The vibration damping actuator includes a hydraulic servo module, an oil reservoir, an oil inlet valve, a piston rod, a sealing ring, a damping force valve, a coil spring, a connecting plate, a lubrication cylinder, an inner cylinder, and an outer cylinder.

[0017] Compared with the prior art, the present invention has the following beneficial effects: The dual-threshold discrimination method for active vibration reduction of ship main engines provided by this invention can accurately identify weak characteristic vibrations in the highly disturbed environment of a ship's engine room and output a highly linear continuous analog drive voltage. Combined with an adaptive algorithm to track frequency shifts in real time, it ensures that the device maintains extremely high cancellation accuracy even under complex operating conditions such as acceleration and deceleration. This method also introduces a dual-threshold hysteresis discrimination mechanism to avoid frequent start-stop cycles near the vibration critical point, protecting precision components such as hydraulic servo valves and significantly reducing the overall system power consumption. A low-latency signal link ensures that the reaction force output by the actuator is phase-opposite to the main engine vibration in real time, achieving optimal physical energy cancellation. It can simultaneously achieve strong adaptability and stability under dynamic operating conditions, as well as high efficiency and real-time performance of the control strategy. Furthermore, this method employs a failure protection and active-passive fusion design. When power is interrupted or the active control logic fails, it can automatically degrade to passive vibration reduction mode by utilizing the inherent damping characteristics and elastic support structure of the hydraulic device. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0019] Figure 1 This is a flowchart of the active vibration reduction method for ship main engines based on dual threshold discrimination provided by the present invention; Figure 2 This is a schematic diagram of the process of active vibration reduction of the ship's main engine in an embodiment of the present invention; Figure 3 This is a schematic diagram of the active vibration reduction device for ship main engines based on dual threshold discrimination provided by the present invention.

[0020] Figure label: 1: Piston rod; 2: Helical spring; 3: Accelerometer; 4: Oil reservoir; 5: Sealing ring; 6: Damping force valve; 7: Hydraulic servo module; 8: Marine main engine; 9: Integrated controller; 10: Engine room sidewall; 11: Oil inlet valve; 12: Lubrication cylinder; 13: Inner cylinder; 14: Outer cylinder; 15: Data storage and processing unit; 16: CNC unit; 17: Mounting base; 18: Data transmission line; 19: Connecting plate; 20: Power module. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0022] This invention provides a method for active vibration reduction of ship main engines based on dual threshold discrimination. Figure 1 This is a flowchart of the active vibration reduction method for ship main engines based on dual threshold discrimination provided by the present invention, as follows: Figure 1 As shown, the method includes the following steps: Step S101: Real-time acquisition of vibration signals from the ship's main engine, and conversion of the vibration signals into electrical signals; the electrical signals are voltage signals or charge signals. Step S102: Perform analog-to-digital conversion and digital bandpass filtering on the electrical signal to separate the vibration frequency band characteristic of the host. Step S103: Based on the vibration frequency band, a dual-threshold hysteresis discrimination mechanism is used to determine the vibration reduction mode for the ship's main engine; the vibration reduction mode includes passive vibration reduction mode and active vibration reduction mode. In step S104, when the active vibration reduction mode is activated, the value of the dynamic counterforce that is out of phase with the vibration of the host machine is determined, and the host machine vibration is actively counteracted.

[0023] In this method, firstly, the vibration signal of the ship's main engine is acquired in real time and converted into a charge signal or voltage signal. Then, the electrical signal undergoes analog-to-digital conversion and digital bandpass filtering to separate the vibration frequency band characteristic of the main engine. Next, a dual-threshold hysteresis discrimination mechanism is employed to determine whether to enter active vibration reduction mode. When active vibration reduction mode is activated, the value of the dynamic counterforce opposite to the main engine vibration is determined, and a corresponding counterforce is generated to actively counteract the main engine vibration. Compared to traditional passive vibration reduction, which relies solely on fixed stiffness and damping parameters to passively absorb energy, this process can dynamically adjust the suppression force in real time according to complex and changing operating conditions. This effectively overcomes the inherent limitations of passive vibration reduction, such as its inability to simultaneously meet high and low frequency vibration isolation requirements and the potential for excessive main engine vibration to damage equipment. It significantly improves the operational stability and safety of the ship's main engine and solves the problem of existing technologies struggling to perform active vibration reduction under complex conditions.

[0024] The above method will now be explained in detail through specific embodiments: Figure 2 This is a schematic diagram illustrating the process of active vibration reduction of a ship's main engine in an embodiment of the present invention, as shown below. Figure 2As shown, firstly, a sensor is used to collect vibration signals. For example, the sensor used in this embodiment has a sensing element consisting of two piezoelectric plates, on which an inertial mass block made of heavy metal is placed. A pre-tensioned rigid spring plate clamps the inertial mass block and the piezoelectric plates onto a base. The entire assembly constitutes an accelerometer. If the natural frequency of the accelerometer is... Obviously:

[0025] in, This represents the combined elastic modulus of the spring plate, piezoelectric element, and base stud. This represents the mass of the inertial mass block. It represents pi (π).

[0026] When using an accelerometer, its sensitivity must be considered. Sensitivity can be expressed in two ways: one is voltage sensitivity. The other is charge sensitivity. The pressure exerted on the piezoelectric element is the inertial force of the pull. From the formula:

[0027] in, Indicates the piezoelectric coefficient. This indicates the amount of charge generated when a piezoelectric element is compressed. This indicates the pressure-bearing area of ​​the piezoelectric element. This represents the dynamic pressure acting on the piezoelectric element. It can be seen that the charge generated on the working surface of the piezoelectric element... With the acceleration of the measured vibration Proportional:

[0028] Among them, the proportionality coefficient This refers to the charge sensitivity of a piezoelectric accelerometer; the open-circuit voltage of the sensor is:

[0029] in, Indicates open-circuit voltage. This indicates the internal capacitance of the sensor; for a specific sensor, It is a definite value. Therefore, the following relationship exists:

[0030] in, This indicates charge sensitivity. In other words, it's the open-circuit voltage of the accelerometer. Also related to the measured acceleration Proportional, proportionality coefficient It refers to voltage sensitivity.

[0031] In actual testing, the vibration frequency of the host computer... It is much lower than the natural frequency of the accelerometer. ,Right now It is obvious that, due to the relative motion between the inertial mass and the base, Since it is also an acceleration sensor, the piezoelectric element is subjected to corresponding alternating pressure, so the acceleration sensor can output a charge proportional to the vibration acceleration being measured.

[0032] In some embodiments, step S102, which involves performing analog-to-digital conversion and digital bandpass filtering on the electrical signal to separate the vibration frequency band characteristic of the host, includes: using Delta-Sigma analog-to-digital conversion logic, differential integral modulation, and noise shaping technology to convert the electrical signal into a high-precision digital signal; and separating the vibration frequency band characteristic of the host through a digital bandpass filter based on a linear time-invariant system; the linearity of the linear time-invariant system satisfies superposition and scalarity.

[0033] When performing digital bandpass filtering, the following band separation logic is executed: the high-pass portion filters out extremely low-frequency interference, and the low-pass portion filters out high-frequency noise.

[0034] For example, the electrical signal is transmitted to the integrated controller via the data transmission line. The data storage and processing unit and the numerical control system in the integrated controller are processed by analog-to-digital conversion and digital bandpass filtering to separate the characteristic vibration frequency band of the host machine.

[0035] Specifically, the processing unit within the integrated controller employs Delta-Sigma analog-to-digital conversion logic, differential integral modulation, and noise shaping techniques to convert the analog vibration voltage acquired by the sensor into a high-precision digital signal. This signal is then filtered by a digital bandpass filter, primarily used to accurately separate the vibration frequency band requiring processing. Its algorithm design is based on the concept of a linear time-invariant system.

[0036] Considering the nonlinear and time-varying characteristics of the ship's main engine during operation due to speed fluctuations, load adjustments, and wave loads, this embodiment does not limit the entire physical system to a linear time-invariant model. Instead, it utilizes the high-frequency sampling characteristics of the integrated controller to discretize the continuous variable operating conditions of the ship's main engine on a microscale along the time axis. Within the micro-control cycle, the system is regarded as a quasi-time-invariant system, thus enabling the linear processing logic to hold.

[0037] To ensure the digital bandpass filter can stably execute the following band separation logic: the high-pass section filters out extremely low-frequency interference, and the low-pass section filters out high-frequency noise, ensuring that the input to the algorithm is a pure host characteristic vibration signal. That is, when the host speed changes, the filter automatically updates its coefficients to ensure that it always locks onto the host characteristic vibration frequency band.

[0038] A linear time-invariant system is a system that simultaneously satisfies linearity and time invariance, where linearity requires both superposition and superposition.

[0039] The secondary expression is as follows: any have

[0040] in, Indicates the system input signal. Indicates the system's output signal. Represents a real constant (gain coefficient).

[0041] The superposition property is expressed as:

[0042] in, Indicates the number of signal sources or subsystems. This represents a continuous-time variable. A time-invariant system is a system that retains its form under time-shift transformations, and its expression is as follows: like but

[0043] in, This represents the time offset (time shift constant).

[0044] In some embodiments, the dual-threshold hysteresis discrimination mechanism is as follows: when the vibration intensity is within the stop threshold, a passive vibration reduction mode is executed, relying solely on the inherent damping and elastic support structure of the hydraulic servo module to absorb minor vibrations; when the vibration intensity exceeds the start threshold, an active vibration reduction mode is executed, and the control chip calculates the canceling force opposite to the host vibration in real time based on a composite strategy of feedforward compensated PID and adaptive algorithm, and outputs the corresponding analog voltage signal to the hydraulic servo valve; the active vibration reduction mode is implemented using a composite architecture of feedforward compensated PID control algorithm and FxLMS algorithm.

[0045] For example, the core processing chip of the CNC system performs calculations and analyses on the filtered signal and uses a built-in "dual-threshold hysteresis" discrimination module to achieve seamless switching between active control and passive vibration reduction. The specific logic is as follows: 1. RMS Value Determination: The processing chip calculates the RMS value in real time. ; 2. Dual threshold discrimination logic: preset start threshold and stopping threshold ,and .

[0046] The passive vibration reduction mode is activated when the real-time vibration intensity is... The chip determines that the current vibration is within the allowable range for normal operation of the ship's main engine. At this time, the chip does not output a voltage drive signal, and the vibration damping actuator does not generate active thrust. Due to the inherent damping characteristics between the hydraulic cylinder piston and the pipeline, and the system having a certain elastic support structure, the entire device relies on its own physical structure to act as a passive vibration damper, absorbing minute vibration energy.

[0047] The active vibration reduction mode is activated when the real-time vibration intensity is... The chip calculates the reaction force required to counteract the current vibration based on its built-in control algorithm. The core processing chip adopts a composite architecture of a PID control algorithm based on feedforward compensation and an FxLMS algorithm. This composite algorithm predicts the vibration phase in advance through an adaptive control algorithm, compensates for the response lag of the hydraulic system, and ensures real-time matching between the physical output force and the vibration waveform.

[0048] The PID control algorithm based on feedforward compensation includes feedforward control and feedback control. Feedforward control determines the required compensation amount based on the known characteristics of the system input signal or external disturbance. Feedback control adjusts the system error through proportional, integral, and derivative actions.

[0049] Specifically, the feedforward-compensated PID control algorithm is an improved control method combining feedforward control and feedback control. It introduces a feedforward compensation channel into traditional PID control to compensate for known disturbances or input signals in advance, thereby enhancing the control system's response speed and disturbance rejection capability. The feedback controller adjusts the system error through proportional, integral, and derivative actions, maintaining the system's accuracy and stability.

[0050] in, This represents the output control quantity of the PID controller. Represents the proportional gain coefficient. Represents the integral gain coefficient. Indicates time The instantaneous error of the system at that point, Represents the differential gain coefficient. It's an error. Indicates the system input signal. This represents the actual output feedback signal of the system.

[0051] The feedforward controller is based on the system input signal. or external disturbances Based on the known characteristics, the required compensation amount is calculated in advance, and the specific formula is as follows:

[0052] in, The compensation amount represents the calculation model of the feedforward compensation, which is usually based on the mathematical model design of the system. It can be the proportion, derivative, or model calculation output of the input signal.

[0053] The calculation formula for the controller output is as follows:

[0054] in, This indicates the controller output. The chip superimposes the optimal reaction force commands calculated by the two algorithms to obtain the total reaction force.

[0055] In some embodiments, after determining the value of the dynamic counterforce that is out of phase with the host vibration in step S103, the method includes: converting the dynamic counterforce into a digital control sequence by scaling and zero-position offset; and utilizing Delta-Sigma ( The modulation algorithm processes the digital control sequence to obtain an analog voltage signal, which is then sent to the hydraulic valves of the ship's main engine.

[0056] For example, the reaction force is converted into a digital sequence by scaling and zero-point offset; subsequently, Delta-Sigma is used. The modulation algorithm processes the digital control sequence. This algorithm uses sampling techniques to shift quantization noise to a higher frequency band, and, in conjunction with a low-pass filter circuit on the chip's periphery, restores the digital quantity to a highly linear continuous analog voltage signal, which is then sent to the hydraulic valve.

[0057] This design avoids frequent start-stop of the vibration damping system under slight vibrations, extends the service life of hydraulic components and servo valves, and reduces system power consumption. In addition, when the system power terminal or chip of the ship's main engine fails and cannot output a signal, it enters passive vibration damping mode to ensure that the connection between the ship's main engine and the hull still has basic flexible support and vibration damping capabilities, and will not cause structural damage due to failure of the active system.

[0058] In some embodiments, step S104, actively counteracting the main engine vibration, includes: adjusting the high-pressure oil flow of the hydraulic actuator of the ship's main engine according to the analog voltage signal to establish a dynamic pressure difference on both sides of the piston; the piston rod of the hydraulic actuator, driven by the pressure difference, generates an active counteracting force that is equal in magnitude and opposite in direction to the vibration force of the ship's main engine, thereby counteracting the main engine vibration.

[0059] An analog voltage signal is input to the hydraulic servo module. The amplitude and polarity of the analog voltage signal directly correspond to the displacement and direction of movement of the servo valve spool. Based on the received voltage signal, the servo valve precisely adjusts the flow rate of high-pressure oil entering the left and right chambers of the hydraulic actuator, thereby establishing a dynamic pressure difference on both sides of the piston. Driven by this pressure difference, the piston rod of the hydraulic actuator generates an active counteracting force equal in magnitude and opposite in direction to the vibration force of the ship's main engine. In passive mode, the vibration intensity... At this time, the hydraulic oil in the hydraulic actuator generates inherent damping force through damping and piston clearance, which, together with the elastic support structure of the hydraulic servo module, fundamentally dissipates the energy of minor vibrations.

[0060] The present invention also provides an active vibration reduction device for ship main engines based on dual threshold discrimination. The active vibration reduction device for ship main engines based on dual threshold discrimination provided by the present invention will be described below. The active vibration reduction device for ship main engines based on dual threshold discrimination described below can be referred to in correspondence with the active vibration reduction method for ship main engines based on dual threshold discrimination described above. Figure 3 This is a schematic diagram of the active vibration reduction device for ship main engines based on dual threshold discrimination provided by the present invention, as shown below. Figure 3 As shown, the device is mounted between the ship's main engine 8 and the engine room sidewall 10 via a mounting base 17, and is characterized by comprising: The sensor system is used to collect vibration signals, including real-time vibration signals from the ship's main engine, and convert the vibration signals into electrical signals. An integrated controller system is used to perform analog-to-digital conversion and digital bandpass filtering on electrical signals, separate the vibration frequency band of the main engine, and determine the vibration reduction mode for the ship's main engine based on the vibration frequency band using a dual-threshold hysteresis discrimination mechanism. Vibration damping system is used to actively counteract the vibration of the host machine.

[0061] Specifically, the sensor system includes an accelerometer 3 and a data transmission line 18; the integrated control system includes an integrated controller 9, a data storage and processing unit 15, a numerical control unit 16, and a power supply module 20; the vibration damping actuator includes a hydraulic servo module 7, an oil reservoir 4, an oil inlet valve 11, a piston rod 1, a sealing ring 5, a damping force valve 6, a coil spring 2, a connecting plate 19, a lubrication cylinder 12, an inner cylinder 13, and an outer cylinder 14.

[0062] Accelerometer 3 collects vibration signals in real time by being attached to the ship's main engine 8 and converts them into charge or voltage signals. The signals are transmitted to the integrated controller 9 via data transmission line 18. The data storage and processing unit 15 and the numerical control unit 16 in the integrated controller 9 separate the characteristic vibration frequency band of the main engine after analog-to-digital conversion and digital bandpass filtering.

[0063] The 16-core CNC unit adopts a "dual threshold hysteresis" discrimination mechanism: when the vibration intensity is lower than the stop threshold, the system is in passive vibration reduction mode, relying solely on the inherent damping of the hydraulic actuator and the elastic support structure to absorb minor vibrations; when the vibration intensity exceeds the start threshold, the system switches to active vibration reduction mode. The control chip, based on a composite strategy of feedforward compensation PID and adaptive algorithm, calculates the counteracting force that is out of phase with the host vibration in real time and outputs the corresponding analog voltage signal to the hydraulic servo valve.

[0064] The vibration damping system precisely adjusts the hydraulic pressure of the hydraulic servo module 7 based on the voltage signal, driving the piston rod 1 to generate a dynamic counterforce, thereby actively counteracting the vibration of the main engine. In the event of a power outage or control failure, the device automatically degrades to a purely passive vibration damping mode, ensuring that basic vibration damping functions are always available and protecting the safety of the ship's main engine and hull structure.

[0065] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0066] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0067] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for active vibration reduction of ship main engines based on dual threshold discrimination, characterized in that, include: The vibration signals of the ship's main engine are collected in real time and converted into electrical signals; The electrical signal is a voltage signal or a charge signal; The electrical signal is subjected to analog-to-digital conversion and digital bandpass filtering to separate the vibration frequency band characteristic of the host. Based on the vibration frequency band, a dual-threshold hysteresis discrimination mechanism is used to determine the vibration reduction mode for the ship's main engine; the vibration reduction mode includes a passive vibration reduction mode and an active vibration reduction mode. When the active vibration reduction mode is activated, the value of the dynamic counterforce that is out of phase with the vibration of the host machine is determined, and the host machine vibration is actively counteracted.

2. The active vibration reduction method for ship main engines based on dual threshold discrimination according to claim 1, characterized in that, The electrical signal is subjected to analog-to-digital conversion and digital bandpass filtering to separate the vibration frequency band characteristic of the host, including: The electrical signal is converted into a high-precision digital signal using Delta-Sigma analog-to-digital conversion logic, differential integral modulation, and noise shaping techniques. Based on a linear time-invariant system, the vibration frequency band of the host machine is separated by a digital bandpass filter; the linearity of the linear time-invariant system satisfies superposition and scalarity.

3. The active vibration reduction method for ship main engines based on dual threshold discrimination according to claim 2, characterized in that, When performing digital bandpass filtering, the following band separation logic is executed: The high-pass filter removes extremely low-frequency interference, while the low-pass filter removes high-frequency noise.

4. The active vibration reduction method for ship main engines based on dual threshold discrimination according to claim 1, characterized in that, The dual-threshold hysteresis discrimination mechanism is as follows: When the vibration intensity is within the stop threshold, the passive vibration reduction mode is executed; When the vibration intensity exceeds the start-up threshold, the active vibration reduction mode is executed; the active vibration reduction mode is implemented using a composite architecture of PID control algorithm based on feedforward compensation and FxLMS algorithm.

5. The active vibration reduction method for ship main engines based on dual threshold discrimination according to claim 4, characterized in that, PID control algorithms based on feedforward compensation include feedforward control and feedback control; The feedforward control is: determining the required compensation amount based on the known characteristics of the system input signal or external disturbance; The feedback control is to adjust the system error through proportional, integral, and derivative actions.

6. The active vibration reduction method for ship main engines based on dual threshold discrimination according to claim 1, characterized in that, After determining the value of the dynamic counterforce that is out of phase with the host vibration, the following steps are taken: The dynamic reverse force is converted into a digital control sequence through scaling and zero-position offset processing; Using Delta-Sigma( The modulation algorithm processes the digital control sequence to obtain an analog voltage signal, which is then sent to the hydraulic valve of the ship's main engine.

7. The active vibration reduction method for ship main engines based on dual threshold discrimination according to claim 6, characterized in that, Actively counteracting host vibration, including: The high-pressure oil flow of the hydraulic actuator of the ship's main engine is adjusted according to the analog voltage signal to establish a dynamic pressure difference on both sides of the piston; Driven by the pressure difference, the piston rod of the hydraulic actuator generates an active counteracting force that is equal in magnitude and opposite in direction to the vibration force of the ship's main engine, thereby counteracting the vibration of the main engine.

8. The active vibration reduction method for ship main engines based on dual threshold discrimination according to claim 1, characterized in that, When the system power terminal or chip of the ship's main engine fails and cannot output a signal, it enters passive vibration reduction mode.

9. A ship main engine active vibration damping device based on dual threshold discrimination, installed between the ship main engine (8) and the engine room sidewall (10) via a mounting base (17), characterized in that, include: The sensor system is used to collect vibration signals, collect vibration signals of the ship's main engine in real time, and convert the vibration signals into electrical signals; An integrated controller system is used to perform analog-to-digital conversion and digital bandpass filtering on the electrical signal to separate the vibration frequency band of the main engine, and to determine the vibration reduction mode for the ship's main engine based on the vibration frequency band using a dual-threshold hysteresis discrimination mechanism. Vibration damping system is used to actively counteract the vibration of the host machine.

10. The active vibration reduction device for ship main engines based on dual threshold discrimination according to claim 9, characterized in that, The sensor system includes an accelerometer (3) and a data transmission line (18). The integrated control system includes an integrated controller (9), a data storage and processing unit (15), a numerical control unit (16), and a power supply module (20). The vibration damping actuator includes a hydraulic servo module (7), an oil reservoir (4), an oil inlet valve (11), a piston rod (1), a sealing ring (5), a damping force valve (6), a helical spring (2), a connecting plate (19), a lubrication cylinder (12), an inner cylinder (13), and an outer cylinder (14).

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