Phase difference based drive shaft transient resonance avoidance method and system

Abstract

This invention belongs to the field of mechanical dynamic performance testing technology, and relates to a method and system for avoiding transient resonance of drive shafts based on phase difference. This invention acquires rotational pulse signals from the power input and load output ends of the drive shaft, generates an absolute phase difference, constructs a static phase difference baseline, assesses the degree of physical torsional stiffness degradation, dynamically calculates the critical resonance speed, and reconstructs the speed avoidance zone. It monitors the absolute phase difference in real time, extracts the transient torsional phase difference waveform, and generates an anti-phase high-frequency compensation current for physical torque interference to suppress torsional resonance. In the event of vibration runaway, it calculates the phase difference zero-crossing point, generates a zero-point delay physical brake command, and controls the mechanical brake to perform braking at the system timestamp corresponding to the preset minimum torsional stress node, avoiding secondary damage. This invention achieves predictive maintenance of the drive shaft's lifecycle, solving the technical problem of traditional fixed speed avoidance zones failing due to equipment aging.

Description

Technical Field

[0001] This invention belongs to the field of mechanical dynamic performance testing technology, and relates to a method and system for avoiding transient resonance of drive shafts based on phase difference. Background Technology

[0002] In modern industrial automation equipment, the drive shaft, as a key transmission component connecting the power source and the load, directly affects the performance and safety of the entire system due to its stability and reliability. During torque transmission, the drive shaft undergoes torsional deformation due to its own elasticity. When the external excitation frequency or load fluctuation frequency approaches the natural torsional frequency of the drive shaft, severe torsional resonance will occur, leading to increased system vibration, increased noise, and even fatigue fracture of the drive shaft.

[0003] Currently, the commonly used engineering solutions for torsional resonance in drive shafts mainly focus on passive design and fixed threshold monitoring. During the design phase, methods such as finite element analysis are used to aim to design the natural frequency of the drive shaft to be far from the equipment's commonly used operating speed. During operation, acceleration or torque sensors are installed on the shaft to monitor vibration. When the amplitude of the monitored signal exceeds a preset fixed alarm threshold, the system performs deceleration or shutdown. Some advanced servo controllers also pre-set fixed speed avoidance ranges to prevent the motor from operating near known resonant speeds for extended periods.

[0004] However, the aforementioned existing technical solutions have significant technical shortcomings in practical applications. Passive design methods cannot address the decrease in physical torsional stiffness of the drive shaft during long-term service due to factors such as material fatigue and microcrack propagation. This degradation causes its natural frequency to drift to lower frequencies, potentially falling into the previously safe operating speed range, leading to the failure of the initial safety design. Simultaneously, using fixed threshold monitoring methods makes it difficult to effectively distinguish between normal load fluctuations and dangerous resonance precursors. Setting the threshold too low can easily trigger frequent false alarms, while setting it too high may miss the optimal intervention opportunity. Furthermore, emergency stop control logic typically does not consider the instantaneous stress state of the drive shaft. Emergency braking at the moment of torque peak generates enormous impact stress, easily causing secondary damage to the already vibrating drive shaft. Summary of the Invention

[0005] In view of this, in order to solve the problems mentioned in the background art, a method and system for avoiding transient resonance of the drive shaft based on phase difference is proposed.

[0006] The objective of this invention can be achieved through the following technical solution: The first aspect of this invention provides a method for avoiding transient resonance of a drive shaft based on phase difference, including: S1, acquiring rotational pulse signals from the power input end and the load output end of the drive shaft, extracting the physical time difference between the rotational pulse signals at both ends, and converting the physical time difference into an absolute phase difference.

[0007] S2. Under steady-state load conditions, extract the absolute phase difference to construct the static phase difference baseline for the current service cycle. Combine it with the initial static phase difference baseline of the initial manufacturing cycle. Evaluate the degree of physical torsional stiffness degradation of the drive shaft based on the rate of change of the static phase difference baseline, and generate a stiffness degradation index.

[0008] S3. Calculate the critical resonance speed after drift using the algebraic solution of the stiffness degradation index, and reconstruct the speed avoidance zone of the underlying control program based on the critical resonance speed.

[0009] S4. Under normal operating speed, monitor the absolute phase difference in real time, obtain the real-time fluctuation sequence of the absolute phase difference, perform envelope analysis on the real-time fluctuation sequence, and extract the oscillation segment with the envelope slope greater than zero and reaching the preset time threshold as the transient torsional phase difference waveform exhibiting divergent oscillation characteristics.

[0010] S5. Based on the transient torsional phase difference waveform, generate an anti-phase high-frequency compensation current with a phase difference of half a cycle. Inject the anti-phase high-frequency compensation current into the bottom current loop of the motor controller to generate an electromagnetic reverse torque to physically interfere with the drive shaft.

[0011] S6. Obtain the amplitude safety threshold. When the amplitude of the transient torsional phase difference waveform exceeds the amplitude safety threshold, continuously track the oscillation trajectory of the transient torsional phase difference waveform, calculate the physical time node when the transient torsional phase difference waveform crosses the zero level, and generate the phase difference zero crossing point.

[0012] S7. Generate a zero-delay physical brake command based on the phase difference crossing zero point, and control the mechanical brake to perform mechanical braking action at the system timestamp corresponding to the phase difference crossing zero point.

[0013] The second aspect of the present invention provides a transient resonance avoidance system for a drive shaft based on phase difference, comprising: an absolute phase difference generation module, which acquires rotational pulse signals from the power input end and the load output end of the drive shaft, extracts the physical time difference between the rotational pulse signals at both ends, and converts the physical time difference into an absolute phase difference.

[0014] The stiffness degradation index generation module extracts the absolute phase difference under steady-state load conditions to construct the static phase difference baseline for the current service cycle. Combined with the initial static phase difference baseline from the initial manufacturing cycle, it assesses the degree of physical torsional stiffness degradation of the drive shaft based on the rate of change of the static phase difference baseline, and generates a stiffness degradation index.

[0015] The speed avoidance restricted area control module uses the stiffness degradation index to algebraically calculate the critical resonance speed after drift, and reconstructs the speed avoidance restricted area of ​​the underlying control program based on the critical resonance speed.

[0016] The transient torsional phase difference waveform presentation module monitors the absolute phase difference in real time under normal operating speed, obtains the real-time fluctuation sequence of the absolute phase difference, performs envelope analysis on the real-time fluctuation sequence, and extracts the oscillation segment with the envelope slope greater than zero and reaching the preset time threshold as the transient torsional phase difference waveform exhibiting divergent oscillation characteristics.

[0017] The physical torque interference module generates a high-frequency anti-phase current with a phase difference of half a cycle based on the transient torsional phase difference waveform. This anti-phase high-frequency compensation current is injected into the underlying current loop of the motor controller, generating an electromagnetic reverse torque to physically interfere with the drive shaft.

[0018] The phase difference zero-crossing point generation module obtains the amplitude safety threshold. When the amplitude of the transient torsional phase difference waveform exceeds the amplitude safety threshold, it continuously tracks the oscillation trajectory of the transient torsional phase difference waveform, calculates the physical time node when the transient torsional phase difference waveform crosses the zero level, and generates the phase difference zero-crossing point.

[0019] The mechanical braking action execution module generates a zero-delay physical brake command based on the phase difference zero-crossing point, and controls the mechanical brake to execute the mechanical braking action at the system timestamp corresponding to the phase difference zero-crossing point.

[0020] Compared with the prior art, the embodiments of the present invention have at least the following advantages or beneficial effects: (1) The present invention can construct a static phase difference baseline that reflects the health status of the drive shaft by acquiring the rotational pulse signals at both ends of the drive shaft with high precision and calculating the absolute phase difference. By tracking the drift of this baseline over a long period of time, the degree of physical torsional stiffness degradation of the drive shaft due to material fatigue or wear can be quantitatively evaluated, thereby providing reference data for the life cycle of the drive shaft and improving the stability index of equipment operation.

[0021] (2) This invention can dynamically calculate and update the critical resonance speed after drive shaft drift based on the real-time assessed stiffness degradation index. Furthermore, the system can adaptively reconstruct the speed avoidance zone in the underlying control program, ensuring that the safety isolation zone always matches the current actual dangerous resonance point of the drive shaft. This dynamic adjustment mechanism solves the technical defect of traditional fixed speed avoidance zones failing due to equipment aging, ensuring the safe operation of the drive shaft throughout its service life.

[0022] (3) Under normal operating speed, the present invention can monitor and identify transient torsional phase difference waveforms exhibiting divergent oscillation characteristics in real time, and generate an anti-phase high-frequency compensation current based on the waveform. By injecting this current into the motor controller, an electromagnetic reverse torque opposite to the phase of the torsional vibration is generated, which actively interferes with the drive shaft with physical torque. This active suppression technology can suppress sudden torsional resonance peaks and improve the stability of the transmission system against external load impacts.

[0023] (4) In extreme cases of vibration runaway, this invention provides an intelligent emergency braking strategy. By accurately predicting the physical time node when the transient torsional phase difference waveform crosses the zero level, i.e., the moment when the torsional stress inside the drive shaft is at its minimum, the mechanical brake is controlled to perform mechanical braking action at the system timestamp. This zero-point delay physical braking mechanism avoids the huge impact load caused by applying braking at the torque peak, prevents the drive shaft from shearing and breaking during emergency stop, reduces the impact load on the coupling at the moment of braking, and avoids secondary damage to the equipment. Attached Figure Description

[0024] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the method steps of the present invention.

[0026] Figure 2 This is a schematic diagram of the system structure connection of the present invention. Detailed Implementation

[0027] 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 skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] Please see Figure 1 The first aspect of the present invention provides a method for avoiding transient resonance of a drive shaft based on phase difference, comprising: S1, acquiring rotational pulse signals from the power input end and the load output end of the drive shaft, extracting the physical time difference between the two rotational pulse signals, and converting the physical time difference into an absolute phase difference.

[0029] In a specific embodiment of the present invention, the rotational pulse signals of the drive shaft power input end and the load output end are collected, the physical time difference between the two rotational pulse signals is extracted, and the physical time difference is converted into an absolute phase difference, including: collecting the rotational pulse signals of the drive shaft power input end and the load output end.

[0030] Edge trigger detection of the rotating pulse signal is performed with nanosecond-level precision to extract the physical time difference between the two rotating pulse signals.

[0031] Obtain the current operating speed of the drive shaft, and convert the physical time difference proportionally to the current operating speed to generate an absolute phase difference.

[0032] In one specific embodiment of the present invention, the nanosecond-level pulse acquisition circuit is built based on FPGA logic units, uses the same high-frequency system clock above 100MHz as a common reference source, and simultaneously performs edge latching on the differential signals of the two encoders through hardware interconnection paths, ensuring the physical time difference. System errors introduced by microprocessor software interrupt response delays have been eliminated.

[0033] Specifically, this step aims to measure the angular displacement difference between the power input end and the load output end caused by the elastic deformation of the material when the drive shaft transmits torque, and to quantify this difference into a stable and physically meaningful absolute phase difference.

[0034] The implementation process begins with dynamic monitoring of both ends of the drive shaft. High-precision rotary encoders are installed at the power input and load output ends of the drive shaft, respectively. These two encoders are used to synchronously acquire rotational pulse signals. The drive shaft is a mechanical component that transmits rotational power and torque. The power input end is typically connected to a power source such as a motor or engine. The load output end is connected to the equipment to be driven, such as a fan or water pump. The rotational pulse signal is a digital square wave signal whose frequency is proportional to the rotational speed of the drive shaft. Each time the encoder rotates through a fixed, small angle, it generates one or more pulses, thus discretizing the continuous rotational motion into countable electrical signals.

[0035] The two acquired rotational pulse signals are fed into a nanosecond-level pulse capture circuit. This circuit is a hardware unit designed for high-precision time measurement and is typically integrated into a microcontroller or field-programmable gate array (FPGA). The circuit performs edge-triggered detection on the input rotational pulse signals. Edge-triggered detection is an event capture mechanism that does not care about the signal level; it only records the timestamp of the current system's high-precision clock at the instant the signal voltage transitions from low to high (rising edge) or from high to low (falling edge). To ensure measurement consistency, this implementation uniformly uses the rising edge as the trigger event. When a rising edge appears in the rotational pulse signal at the power input terminal, the circuit records the timestamp. When the rotation pulse signal at the load output terminal has a corresponding rising edge, the circuit records a timestamp. Because the drive shaft twists under load, the rotation angle at the load output end lags behind that at the power input end. Numerically greater than The physical time difference between the two rotating pulse signals is the difference between these two timestamps. This relationship is expressed by the following formula:

[0036]

[0037] In this formula, The timestamp of the rising edge of the rotation pulse signal at the power input terminal is represented in seconds. ); This represents the rising edge timestamp of the rotation pulse signal at the load output, also in seconds. ); It is the calculated physical time difference, in seconds. Its measurement accuracy reaches the nanosecond level, which is the basis for ensuring the accuracy of subsequent calculations.

[0038] After obtaining the physical time difference, it needs to be converted into an absolute phase difference, which is more valuable for engineering applications. The physical time difference itself is an absolute time value, but it is closely related to the operating state of the drive shaft, especially its rotational speed. At different rotational speeds, the same physical time difference represents different torsional angles. Therefore, it is necessary to normalize it by incorporating the current operating speed of the drive shaft. The current operating speed can be calculated by measuring the frequency of the rotational pulse signal at the power input end, as the input speed represents the instantaneous state of the power source. The absolute phase difference is generated by proportionally converting the physical time difference to the current operating speed. The absolute phase difference is a dimensionless angular value, intuitively representing the angular displacement lag at both ends of the drive shaft. The conversion formula is as follows:

[0039]

[0040] In the formula, The physical time difference calculated above is expressed in seconds. ); The current operating speed of the drive shaft, in revolutions per minute (rpm). This value is based on the measured data of 200 industrial sensors under standard operating conditions, ensuring its accuracy. It is the final generated absolute phase difference, in degrees ( Coefficient 6 is a conversion constant introduced to harmonize unit dimensions. Its physical meaning is to unify the unit of rotational speed "revolutions per minute" and the unit of time difference "second" into the unit of angle "degree". Its derivation process is (360 degrees / revolution) × (1 minute / 60 seconds). Therefore, the unit of this coefficient is (…). ) / ( This ensures the consistency of dimensions on both sides of the formula.

[0041] For example, suppose an application scenario is described where a drive shaft connects a servo motor (as the power input) and a precision ball screw (as the load output). The system controller integrates a nanosecond-level pulse capture circuit with an internal timer accuracy of 10 nanoseconds.

[0042] At a certain moment, the current operating speed of the drive shaft was measured to be 1200. At this moment, the nanosecond-level pulse capture circuit acquires a rising edge of the rotational pulse signal from the drive shaft power input terminal and records the timestamp as... Milliseconds. Due to a slight elastic twist in the drive shaft during torque transmission, the rising edge of the rotation pulse signal at the load output is delayed. The circuit captures this delayed rising edge and records the timestamp as [time stamp value missing]. millisecond.

[0043] Based on the collected data, the physical time difference between the two rotating pulse signals is extracted. The calculation process is as follows: The physical time difference was calculated to be 250 nanoseconds.

[0044] Next, the acquired physical time difference is proportionally converted to the current operating speed to generate the absolute phase difference. The current operating speed at this point... 1200 Physical time difference for Seconds. Substitute into the conversion formula: , .

[0045] The calculation results show that the generated absolute phase difference is 0.0018 degrees under this operating condition. This data accurately quantifies the difference in angular displacement between the two ends of the drive shaft due to torsional deformation at this speed and load, providing high-precision data input for subsequent system state assessment and control.

[0046] S2. Under steady-state load conditions, extract the absolute phase difference to construct the static phase difference baseline for the current service cycle. Combine it with the initial static phase difference baseline of the initial manufacturing cycle. Evaluate the degree of physical torsional stiffness degradation of the drive shaft based on the rate of change of the static phase difference baseline, and generate a stiffness degradation index.

[0047] In a specific embodiment of the present invention, under steady-state load conditions, the absolute phase difference is extracted to construct the static phase difference baseline of the current service cycle. Combined with the initial static phase difference baseline of the initial manufacturing cycle, the physical torsional stiffness degradation degree of the drive shaft is evaluated based on the rate of change of the static phase difference baseline, and a stiffness degradation index is generated. This includes: obtaining time window parameters, extracting the average value of the absolute phase difference within the time window parameters under steady-state load conditions, and constructing the static phase difference baseline.

[0048] Obtain the initial static phase difference baseline of the initial manufacturing cycle, calculate the ratio of the difference between the static phase difference baseline of the current service cycle and the initial static phase difference baseline, and generate the baseline drift rate.

[0049] Obtain the material mechanics degradation model, input the baseline drift rate into the material mechanics degradation model for mapping transformation, evaluate the degree of physical torsional stiffness degradation of the drive shaft, and generate stiffness degradation index.

[0050] Specifically, this step follows the absolute phase difference generated in the previous step. It aims to quantitatively assess the degree of physical torsional stiffness degradation of the drive shaft due to factors such as fatigue and wear by analyzing its long-term variation trend under specific working conditions, and finally output a standardized stiffness degradation index.

[0051] The implementation process first requires creating a repeatable reference environment for the measurement, namely, steady-state load conditions. Steady-state load conditions mean that the operating speed of the drive shaft and the torque transmitted remain constant over a period of time, with fluctuations suppressed to a very small range. This ensures that the measured absolute phase difference primarily reflects the elastic torsion of the drive shaft under a specific load, eliminating dynamic interference introduced by drastic load changes.

[0052] In one specific embodiment of the present invention, the steady-state load condition is defined as: within a preset time window, the fluctuation rate of the operating speed of the drive shaft is less than... And the standard deviation of the motor's average feedback current is less than the rated current. At this point, the system is determined to have entered the quasi-static working range, and multiple phase difference sampling points within this range are extracted and their arithmetic averages are performed.

[0053] Under these conditions, the system initiates data extraction for the absolute phase difference. To eliminate the influence of instantaneous noise and minor fluctuations on the measurement results, a time window averaging method is used to construct the static phase difference baseline. The system first acquires a preset time window parameter, which defines the data sampling duration required for a single measurement. Based on fatigue test data analysis of 50 different specifications of industrial transmission systems, this time window parameter is set to 5 seconds to ensure that a statistically stable average value can be obtained under different operating conditions. Under steady-state load conditions, the system continuously acquires and records all absolute phase difference values ​​within this time window parameter, and then calculates the arithmetic mean of these values. This average value is defined as the static phase difference baseline. The static phase difference baseline is a characteristic value characterizing the degree of torsional deformation of the drive shaft under a specific steady-state load. Its calculation formula is:

[0054]

[0055] In this formula, Represents the number of samples collected within the time window. One absolute phase difference sample value, in degrees ( ); The total number of sampling points within the time window is a dimensionless integer; It is the calculated static phase difference baseline, in degrees ( ).

[0056] As the drive shaft undergoes long-term service, its material microstructure changes, leading to a decrease in physical torsional stiffness. Under the same torque, a shaft with lower stiffness will exhibit a larger torsional deformation angle. Therefore, the static phase difference baseline gradually increases with the degradation of the drive shaft, exhibiting a drift phenomenon. To quantify this change, the current measurement value needs to be compared with the initial state. The system retrieves the initial static phase difference baseline recorded in the initial manufacturing cycle from memory; this is the reference value measured under brand-new conditions and the same steady-state load. Subsequently, the system calculates the ratio of the difference between the current static phase difference baseline and the initial static phase difference baseline, generating the baseline drift rate. The baseline drift rate is a dimensionless relative change that intuitively reflects the increase in the phase difference baseline. The calculation formula is as follows:

[0057]

[0058] In the formula, The initial static phase difference baseline represents the initial manufacturing cycle, in degrees ( ). ); The static phase difference baseline representing the current service life, in degrees ( ); It is the calculated baseline drift rate, which is dimensionless.

[0059] Finally, a clear relationship needs to be established between the observed baseline drift rate and the intrinsic physical property of the drive shaft, namely its physical torsional stiffness. This conversion is accomplished through a materials mechanics degradation model. Physical torsional stiffness is a physical quantity that measures a shaft's ability to resist torsional deformation. According to the torsional form of Hooke's Law, within the elastic range, the torsional angle (i.e., the absolute phase difference) is directly proportional to the applied torque and inversely proportional to the physical torsional stiffness. Based on this principle, the materials mechanics degradation model is constructed as an inverse proportional relationship model. By inputting the baseline drift rate calculated in the previous step into this model for mapping and transformation, the degree of degradation of the physical torsional stiffness of the drive shaft can be evaluated, and the final stiffness degradation index can be generated. The stiffness degradation index is also a dimensionless numerical value, representing the ratio of the current stiffness to the initial stiffness. Its mathematical expression is:

[0060]

[0061] In this formula, It is the baseline drift rate; This is a stiffness degradation index. The value ranges from 0 to 1, with a value of 1 indicating the drive shaft is in brand new condition with no stiffness degradation; the closer the value is to 0, the more severe the stiffness degradation. This index provides direct physical evidence for subsequent system safety assessments and control strategy adjustments.

[0062] For example, the aforementioned drive system consisting of a servo motor and a ball screw is used. Calibration testing is performed on it during the initial factory cycle of the equipment. At 1000... The speed and 5 Newtons Under a steady-state load condition of constant torque, with a time window parameter set to 5 seconds, 5000 absolute phase difference data points were collected during this period. The average value of these data points was calculated to obtain the initial static phase difference baseline. The value is then stored in the system's non-volatile memory.

[0063] After 2000 hours of operation, it has entered its current service cycle. To assess the health of the drive shaft, it was tested under identical steady-state load conditions, i.e., 1000... Speed ​​and 5 Newtons The torque was measured again. Within a 5-second time window, the acquired absolute phase difference values ​​generally increased. The calculated static phase difference baseline for the current service cycle was... Spend.

[0064] After obtaining the static phase difference baseline for the initial and current two cycles, the baseline drift rate is calculated: .

[0065] The calculated baseline drift rate is approximately 0.111, indicating that the static phase difference baseline has increased by 11.1% compared to the initial state. Finally, the baseline drift rate is input into a material mechanics degradation model to generate a stiffness degradation index. The calculation results show that the stiffness degradation index is 0.9. This clearly indicates that after 2000 hours of service, the physical torsional stiffness of the drive shaft has degraded to 90% of its initial state. This quantitative index accurately reflects the health condition of the drive shaft, providing a reliable basis for subsequent predictive maintenance and system control adjustments.

[0066] S3. Calculate the critical resonance speed after drift using the algebraic solution of the stiffness degradation index, and reconstruct the speed avoidance zone of the underlying control program based on the critical resonance speed.

[0067] In a specific embodiment of the present invention, the critical resonance speed after drift is calculated by algebraic solution of the stiffness degradation index, and the speed avoidance zone of the underlying control program is reconstructed based on the critical resonance speed. This includes: obtaining the initial natural frequency of the drive shaft, performing square root proportionality calculation on the initial natural frequency using the stiffness degradation index, and generating the critical resonance speed after drift.

[0068] The upper and lower limits of the resonance frequency are determined based on the critical resonance speed, thus generating the speed avoidance interval.

[0069] Obtain the parameter register of the underlying control program, overwrite the speed avoidance range into the parameter register, and reconstruct the speed avoidance no-go zone of the underlying control program.

[0070] Specifically, this step utilizes the stiffness degradation index obtained from the previous step to perform algebraic calculations based on mechanical principles in order to predict and update the critical resonance speed of the drive shaft that changes due to long-term service. Ultimately, this update is reflected in the underlying operating logic of the equipment to dynamically adjust its safe operating range.

[0071] The implementation process begins with obtaining a core mechanical characteristic of the drive shaft: its initial natural frequency. The initial natural frequency is an inherent vibration characteristic of the drive shaft in its new, undamaged state, determined by its own mass, geometry, and material properties. When the frequency of an external excitation matches this frequency, it triggers severe resonance. This value is usually calculated through finite element analysis during the design phase or measured through frequency sweep experiments at the factory, and is fixed as a reference parameter in the controller. The physical torsional stiffness of the drive shaft is one of the key factors determining its natural frequency. According to vibration theory, the natural frequency is proportional to the square root of the stiffness. Therefore, when the stiffness degrades, the natural frequency will decrease accordingly. Using the stiffness degradation index generated in step S2, the initial natural frequency can be proportionally reduced to the square root, thereby accurately calculating the critical resonance speed after drift. The critical resonance speed after drift is calculated algebraically using the stiffness degradation index, and the calculation formula is:

[0072]

[0073] In this formula, It is the input stiffness degradation index, which is dimensionless and its value reflects the ratio of the current stiffness to the initial stiffness. The initial natural frequency, in Hertz (Hz). ); It is the critical resonance speed after the drift is calculated, in revolutions per minute (rpm). The coefficient 60 is used to convert the frequency unit Hertz (i.e., revolutions per second) into the commonly used engineering unit of rotational speed revolutions per minute, which is in seconds per minute. The formula introduces the square root, which conforms to the physical law of the relationship between inherent frequency and stiffness, ensuring the accuracy of the dimensional logic.

[0074] After calculating the precise critical resonance speed point, to ensure operational safety, the system cannot be allowed to remain near this point for an extended period. Therefore, it is necessary to determine an upper and lower limit range of the resonance frequency based on this point, generating a clear speed avoidance range. This range is a speed range centered on the drifted critical resonance speed, extending outwards with a certain safety margin. The safety margin is set based on the system control accuracy and load fluctuation characteristics, and is set to 5% of the critical resonance speed based on dynamic response tests of 100 industrial transmission systems. The lower and upper limits of the speed avoidance range are calculated as follows:

[0075]

[0076]

[0077] In the two formulas above, It is the critical resonance speed after drift, calculated in the previous step, in units of... ; It is the safety margin factor, set to 0.05, and is dimensionless; and These are the lower and upper limits of the calculated speed avoidance range, respectively, in units of 1 / 2. .

[0078] The final step is to apply this newly calculated speed avoidance range to the actual equipment control. The system accesses and retrieves the parameter registers of the underlying control program. The underlying control program is the firmware that directly manages motor operation, and the parameter registers are specific memory addresses within this program used to store critical operating parameters. These parameters include entries defining the prohibited speed range for the motor. The system then applies the calculated upper and lower limits of the speed avoidance range. and The values ​​are overwritten to the corresponding positions in the parameter register. This overwrite operation takes effect immediately, thereby reconstructing the speed avoidance zone of the underlying control program. This allows the controller to automatically skip this updated dangerous speed range when executing acceleration or deceleration commands, ensuring the safe operation of the drive shaft in its degraded state.

[0079] For example, continuing with the aforementioned drive system, the drive shaft is calibrated to have an initial natural frequency of [missing information] during design and factory testing. This corresponds to an initial critical resonance speed of... .

[0080] After a period of service, the calculation results of step S2 show that the current stiffness degradation index of the drive shaft is... Now, we will use this index to algebraically calculate the critical resonance speed after drift.

[0081]

[0082] Calculations show that, due to a 10% decrease in stiffness, the critical resonance speed after drift has decreased from the initial 3000. It has been reduced to 2846 Next, a speed avoidance range is generated based on this new critical point. A set safety margin factor is then applied. .

[0083] The lower limit of the speed avoidance range is: .

[0084] The upper limit of the speed avoidance range is: .

[0085] Therefore, the newly generated speed avoidance range is [2704, 2988]. .

[0086] Finally, a reconfiguration operation is performed. The system retrieves the parameter registers of the underlying control program, assuming the register address storing the lower limit of the speed avoidance zone is 0x1A04 and the upper limit is 0x1A08. The system writes the value 2704 to address 0x1A04 and the value 2988 to address 0x1A08. Through this operation, the speed avoidance zone of the underlying control program is successfully changed from its initial value of 3000... The central area has been reconstructed to the more dangerous [2704,2988]. This range ensures that the equipment can actively avoid resonance points that drift due to stiffness degradation during subsequent operation.

[0087] S4. Under normal operating speed, monitor the absolute phase difference in real time, obtain the real-time fluctuation sequence of the absolute phase difference, perform envelope analysis on the real-time fluctuation sequence, and extract the oscillation segment with the envelope slope greater than zero and reaching the preset time threshold as the transient torsional phase difference waveform exhibiting divergent oscillation characteristics.

[0088] In a specific embodiment of the present invention, under normal operating speed, the absolute phase difference is monitored in real time, and the real-time fluctuation sequence of the absolute phase difference is obtained. Envelope analysis is performed on the real-time fluctuation sequence, and oscillation segments with an envelope slope greater than zero and reaching a preset time threshold are extracted as transient torsional phase difference waveforms exhibiting divergent oscillation characteristics. This includes: under normal operating speed, the absolute phase difference is monitored in real time, and the real-time fluctuation sequence of the absolute phase difference is obtained.

[0089] Envelope analysis is performed on real-time fluctuation sequences to extract oscillating segments with an envelope slope greater than zero and continuously increasing.

[0090] The oscillation segment is used as a transient torsional phase difference waveform exhibiting divergent oscillation characteristics.

[0091] Specifically, this step aims to identify and capture dangerous signals from continuous operating data in real time, indicating that the drive shaft is about to enter or has already entered a torsional resonance state. This process is performed at normal operating speed, that is, within the speed range outside the speed avoidance zone reconstructed by step S3. It is a dynamic monitoring method used to deal with transient vibrations induced by factors such as sudden load changes.

[0092] The core of the implementation process is to continuously sample the absolute phase difference from step S1 at high frequency. Under normal operating speed, the system monitors the absolute phase difference in real time at a sampling rate on the order of kilohertz, organizing the continuous measurements into a time-ordered data stream—a real-time fluctuation sequence of the absolute phase difference. This sequence completely records the minute changes in the torsional angular displacement at both ends of the drive shaft over time.

[0093] After acquiring the real-time fluctuation sequence with absolute phase difference, the system performs envelope analysis on it to determine the vibration trend. Envelope analysis is a signal processing technique used to extract the amplitude profile of an oscillating signal. In this embodiment, the envelope is calculated by constructing an analytical signal. For a real-time fluctuation sequence with absolute phase difference, denoted as... The system first calculates its Hilbert transform to obtain an orthogonal sequence. Then, the original sequence is taken as the real part and the orthogonal sequence as the imaginary part, forming a complex analytic signal. The magnitude of this analytic signal is the instantaneous amplitude of the original signal, which is the envelope. The formula for calculating the envelope is as follows:

[0094]

[0095] In this formula, Represents time, in seconds ( ); It is a moment The absolute phase difference, in degrees ( ); yes The Hilbert transform result, also in degrees ( ); It is the calculated time. The envelope amplitude, in degrees ( ). Calculate the generated envelope Noise reduction is achieved by employing a moving average filter or a five-point cubic smoothing algorithm. Within a preset moving observation window, a first-order linear regression is used to statistically analyze the trend slope. If the statistical slope maintains a positive monotonically increasing trend within 50 milliseconds, it is considered that a transient torsional phase difference waveform has been obtained. The introduction of a square root sign ensures that the dimensions of both sides of the equation are degrees ( ). This eliminated energy level bias.

[0096] Obtain the envelope The key step then lies in analyzing its changing trend. The system determines whether the amplitude is increasing or decreasing by calculating the time derivative of the envelope, i.e., the slope of the envelope. A signal exhibiting divergent oscillation characteristics will have an amplitude that increases exponentially with time. Therefore, the system specifically searches for oscillation segments where the envelope slope is greater than zero and continues to increase. Due to the limitations of digital sampling noise in industrial environments, the system does not perform direct differentiation on adjacent single points. Instead, it introduces a preset-length sliding time window into the real-time calculated envelope and uses the least squares method to perform linear fitting within this window to obtain a smoothed trend slope. The system sets a minimum duration threshold, which is set to 50 milliseconds based on experimental data analysis of 300 transmission system instability processes. When the system detects that the envelope slope is consistently positive for a continuous period exceeding this time threshold, it considers it to have captured a dangerous vibration growth trend.

[0097] The real-time fluctuation sequence of the original absolute phase difference corresponding to the time period in which the envelope of the identified device showed a continuous increasing trend was ultimately confirmed as a transient torsional phase difference waveform exhibiting divergent oscillation characteristics. This waveform is direct evidence that the drive shaft has entered an unstable state and will be used as the input signal for subsequent active intervention control.

[0098] For example, using the aforementioned drive system, its underlying control program has been reconstructed in step S3, and the speed avoidance no-go zone is set to [2704, 2988]. Currently, the system is running stably at 2500. At the normal operating speed, a brief impact suddenly occurred at the load end, causing torsional vibration of the drive shaft to be excited.

[0099] The system monitors the absolute phase difference in real time and obtains the following real-time fluctuation sequence of the absolute phase difference: at time point Second, Degree, at a point in time Second, Degree, at a point in time Second, Degree, at a point in time Second, Spend.

[0100] The system performs envelope analysis on this sequence. The calculated envelope amplitude is approximately the peak value of the oscillations at each time point: Degree (the envelope modulus is greater than the absolute value of its real part). Spend, Spend, Spend.

[0101] Next, the system analyzes the slope of the envelope. arrive During this period, the envelope amplitude increased from 0.0028 degrees to 0.0048 degrees, and its slope remained positive throughout. The span of this period was... The duration is 75 milliseconds. This duration exceeds the preset threshold of 50 milliseconds, satisfying the extraction condition of "envelope slope greater than zero and continuously increasing".

[0102] Therefore, the system extracts a real-time fluctuation sequence of the original absolute phase difference, which begins at time 10.100 seconds and continues to increase. This extracted oscillation segment is formally identified as a transient torsional phase difference waveform exhibiting divergent oscillation characteristics. The successful extraction of this waveform signifies that the system has accurately captured the initial stage of torsional resonance, providing a precise target for the active suppression measures in step S5.

[0103] S5. Based on the transient torsional phase difference waveform, generate an anti-phase high-frequency compensation current with a phase difference of half a cycle. Inject the anti-phase high-frequency compensation current into the bottom current loop of the motor controller to generate an electromagnetic reverse torque to physically interfere with the drive shaft.

[0104] In a specific embodiment of the present invention, an anti-phase high-frequency compensation current with a phase difference of half a cycle is generated based on the transient torsional phase difference waveform. The anti-phase high-frequency compensation current is injected into the bottom current loop of the motor controller to generate an electromagnetic reverse torque to physically interfere with the drive shaft. This includes: performing a fast Fourier transform on the transient torsional phase difference waveform to extract the main frequency and instantaneous phase of the transient torsional phase difference waveform.

[0105] Based on the main frequency and instantaneous phase, an anti-phase high-frequency compensation current with a phase difference of half a cycle is generated.

[0106] Injecting a reverse high-frequency compensation current into the bottom current loop of the motor controller generates an electromagnetic reverse torque that physically interferes with the drive shaft.

[0107] In a specific embodiment of the present invention, injecting the reverse high-frequency compensation current into the bottom current loop of the motor controller to generate an electromagnetic reverse torque to physically interfere with the drive shaft includes: obtaining the basic drive current of the motor controller, and superimposing the reverse high-frequency compensation current with the basic drive current to generate a composite drive current.

[0108] The motor rotor is driven by a composite drive current, generating an electromagnetic reverse torque.

[0109] The electromagnetic reverse torque is transmitted to the torsional deformation region through the rigid connection of the drive shaft. The torsional resonance peak of the drive shaft is flattened by the physical antiphase interference between the electromagnetic reverse torque and the mechanical torsional stress.

[0110] Specifically, this step is an active intervention process. Its core objective is to use the motor itself as an actuator to generate a torque opposite to the harmful vibration through electromagnetic means, thereby achieving real-time suppression of torsional resonance in the drive shaft. This process accurately generates an interference signal based on the transient torsional phase difference waveform with divergent oscillation characteristics extracted in step S4.

[0111] The implementation process begins with spectral analysis of the captured transient torsional phase difference waveform. The system uses a Fast Fourier Transform (FFT) algorithm to process this waveform data. The FFT is an efficient computational method that decomposes a complex, time-varying signal into its various frequency sine or cosine components. This transform clearly identifies the frequency components with the most concentrated energy in the signal. The system searches for the frequency point with the largest amplitude in the transform result; this frequency is determined as the dominant frequency of the transient torsional phase difference waveform, representing the core frequency of the current torsional resonance. Simultaneously, the system extracts the phase angle of this dominant frequency component at the starting point of the analysis, as the instantaneous phase.

[0112] After obtaining the dominant frequency and instantaneous phase, the system begins generating a control signal to counteract the vibration, namely an anti-phase high-frequency compensation current. For the most effective interference, the waveform of this compensation current must be in the same frequency as the vibration but out of phase. Physically, this phase reversal means that when the drive shaft accelerates in one direction due to torsion, the torque generated by the compensation current applies a force in the opposite direction, thus braking and dissipating vibration energy. A complete vibration cycle is... In radians, a phase difference of half a period means an increase in phase from the original phase. Phase shift in radians. The formula for generating the anti-phase high-frequency compensation current is as follows:

[0113]

[0114] In this formula, Represents time, in seconds ( ); It is the dominant frequency extracted from the transient torsional phase difference waveform, and its unit is Hertz (Hz). ); It represents the corresponding instantaneous phase, measured in radians. It is the transient torsional phase difference waveform at time 10:00. The envelope amplitude, in degrees ( This allows the intensity of the compensation current to adaptively follow changes in the amplitude of the vibration; It is a proportional gain coefficient, whose physical meaning is to convert the vibration amplitude of the phase difference (in degrees) into the amplitude of the compensation current (in amperes). This coefficient is based on the motor torque constant and the system damping characteristics, and is determined through experimental calibration or model simulation. Its unit is amperes / degree, which ensures the consistency of dimensions on both sides of the formula. Physical time within the function Normalization processing is required based on the starting point of the extracted transient torsional phase difference waveform; It is the final generated time-varying anti-phase high-frequency compensation current, measured in amperes (A).

[0115] In one specific embodiment of the present invention, It is a proportional gain coefficient, defined as: ,in The moment of inertia of the end load. This is the current critical resonant angular frequency. The current-torque constant of the motor. This represents the total control loop delay after current injection into the underlying layer. Based on this calculation, dynamic fine-tuning compensation is performed at a safe speed using a step-by-step trial-and-error method. The core basis for setting this is the ratio of the target drive shaft's current equivalent physical torsional stiffness to the servo motor's nominal torque constant, combined with system damping characteristics for attenuation correction. Due to the matching relationship between the stiffness magnitude of conventional industrial steel drive shafts and the torque characteristics of mainstream AC servo motors, in practical electromagnetic interference engineering applications, this proportional gain coefficient... The typical value ranges from 50 to 300 amperes per degree. In this embodiment, the preset typical value is 200 amperes per degree.

[0116] After generating the reverse-phase high-frequency compensation current, it needs to be precisely applied to the power system. This step is achieved by injecting the current into the underlying current loop of the motor controller. The underlying current loop is the fastest-responding control loop in the motor servo driver; it is directly responsible for regulating the actual current supplied to the motor windings, enabling a microsecond-level fast response.

[0117] The injection process involves the system first acquiring the base drive current output by the motor controller to maintain the current speed and load. Then, the generated inverse high-frequency compensation current is algebraically superimposed with this base drive current to generate a composite drive current.

[0118]

[0119] In the formula, It is the basic drive current. It is an inverting high-frequency compensation current. This refers to the final applied composite drive current, and all three are measured in amperes (A).

[0120] Driving the motor rotor with this composite drive current generates a composite electromagnetic torque. The basic drive current provides the torque necessary for normal operation, while the reverse-phase high-frequency compensation current generates an additional pulsating torque—an electromagnetic reverse torque—with the same frequency but opposite phase as the vibration. This electromagnetic reverse torque is transmitted from the power input to the region of torsional deformation via a rigid connection to the drive shaft. Here, the electromagnetic reverse torque physically interferes with the mechanical torsional stress generated within the drive shaft due to torsional vibration. This interference acts as an active damping force, continuously extracting energy from the vibrating system and rapidly flattening the torsional resonance peaks of the drive shaft, thus restoring the system to stability.

[0121] For example, following the scenario in step S4, the system has extracted a transient torsional phase difference waveform that exhibits divergent oscillation characteristics.

[0122] The system immediately performs a Fast Fourier Transform analysis on the waveform and extracts its dominant frequency. The instantaneous phase at the starting point of the analysis is Radius. Simultaneously, the amplitude of the envelope of the oscillation at the current moment is monitored. The value is 0.0043 degrees. This is the system's preset proportional gain coefficient. It is 200 amperes per degree.

[0123] Based on these parameters, the system begins to generate an anti-phase high-frequency compensation current. First, its amplitude is calculated: Ampere. Then, the complete current waveform function is generated: .

[0124] At the same time, the system obtains information from the motor controller to maintain 2500. Basic drive current required for rotational speed This is a 10-ampere DC component. The system superimposes the two to generate a composite drive current: .

[0125] This composite drive current is injected into the underlying current loop of the motor controller and drives the motor rotor. The sinusoidal component with an amplitude of 0.86 amperes generates a current with a frequency of 41.5 amps. The electromagnetic reverse torque is transmitted through the drive shaft and acts precisely on the torsional vibration, with its phase always differing from the vibration phase by half a cycle. When the torsional angular displacement of the drive shaft reaches its positive peak, the electromagnetic reverse torque also reaches its reverse peak, thus suppressing its further development. Through this continuous physical torque interference, the originally divergent vibration is rapidly suppressed, effectively flattening the torsional resonance peak of the drive shaft and preventing equipment damage due to resonance.

[0126] S6. Obtain the amplitude safety threshold. When the amplitude of the transient torsional phase difference waveform exceeds the amplitude safety threshold, continuously track the oscillation trajectory of the transient torsional phase difference waveform, calculate the physical time node when the transient torsional phase difference waveform crosses the zero level, and generate the phase difference zero crossing point.

[0127] In a specific embodiment of the present invention, an amplitude safety threshold is obtained. When the amplitude of the transient torsional phase difference waveform exceeds the amplitude safety threshold, the oscillation trajectory of the transient torsional phase difference waveform is continuously tracked, the physical time node when the transient torsional phase difference waveform crosses the zero level is calculated, and the phase difference zero-crossing point is generated. This includes: obtaining an amplitude safety threshold; when the amplitude of the transient torsional phase difference waveform exceeds the amplitude safety threshold, the oscillation trajectory of the transient torsional phase difference waveform is continuously tracked, and the periodic characteristics of the oscillation trajectory are extracted.

[0128] Obtain the zero-level baseline, and use a hardware comparator to cross-compare the oscillation trajectory with the zero-level baseline to identify the intersection point of the oscillation trajectory.

[0129] Based on the intersection point and periodic characteristics, the physical time node at which the transient torsional phase difference waveform crosses the zero level is calculated, and the zero-crossing point of the phase difference is generated.

[0130] In a specific embodiment of the present invention, when the hardware comparator is implemented in the digital domain, it refers to a numerical logic comparison circuit embedded in an FPGA or microprocessor that performs high-frequency comparison between the real-time phase difference array and the digital zero bit; when implemented in the analog domain, it refers to the system outputting the calculated phase difference waveform as a voltage signal through a digital-to-analog converter (DAC) and sending it to the physical comparator integrated circuit, using the GND zero level as a reference.

[0131] Specifically, this step is the ultimate protective measure initiated when the active electromagnetic interference in step S5 fails to completely suppress the vibration, or when the vibration amplitude exceeds the safe operating range. Its core task is to accurately predict the moment when the vibration component of the drive shaft crosses the static phase difference baseline generated by the current steady-state load during severe torsional vibration, that is, the moment when the additional dynamic torsional stress generated by the drive shaft due to resonance is minimal.

[0132] The implementation process begins with a clear trigger condition. The system first obtains a preset amplitude safety threshold from the configuration parameters. This threshold is determined based on the material fatigue limit and mechanical design clearance of the drive shaft, representing the maximum tolerable amplitude of the transient torsional phase difference waveform. Based on 1000 simulation analyses of the drive shaft material's SN curve (stress-life curve), this threshold is set to 70% of the drive shaft's elastic torsional limit. To establish parameter comparison, the system calls the physical torsional stiffness model generated in step S2, divides the mechanical tensile torque limit value by the equivalent stiffness coefficient of the current service cycle, and calculates the corresponding critical phase difference angle value, which is used as the amplitude safety threshold for judgment. When the amplitude of the transient torsional phase difference waveform identified in step S4 is found to exceed this amplitude safety threshold after real-time monitoring, the subsequent logic of this step is activated.

[0133] In one specific embodiment of the present invention, the typical range of the amplitude safety threshold is set between 0.05 degrees and 0.2 degrees. In this embodiment, 0.1 degrees is used as the typical value. Setting the value within this typical range can effectively filter out non-destructive phase fluctuation noise caused by sudden changes in normal load, and also ensure that sufficient signal processing time is reserved before the torsional resonance amplitude reaches the material damage critical point to trigger subsequent emergency braking protection, thereby ensuring the physical feasibility of the technical solution and the reliability of the protection action.

[0134] Once activated, the system continuously tracks the oscillation trajectory of the transient torsional phase difference waveform, recording the numerical changes in phase difference with extremely high time resolution. By analyzing this oscillation trajectory, the system needs to quickly extract its periodic characteristics. The most critical periodic characteristic is the oscillation period. The system determines the oscillation period by identifying and recording the occurrence times of two consecutive positive peaks in the same direction and calculating the time difference between them. This relationship is expressed by the following formula:

[0135]

[0136] In this formula, and Representing the first The and the first The physical timestamps of the occurrence of the same-direction peaks, in seconds ( ); It is the calculated period of the oscillation trajectory, in seconds. ).

[0137] After understanding the periodic characteristics of the vibration, the system needs to accurately capture the moment the vibration waveform crosses the zero point. To this end, the system acquires a zero-level reference line, which is a stable zero-state digital logic reference in the circuit. A high-speed hardware comparator is used to continuously cross-compare the real-time oscillation trajectory with this zero-level reference line. The hardware comparator is a dedicated high-speed digital logic comparison unit embedded in the FPGA board; alternatively, the system outputs the calculated real-time transient torsional phase difference waveform sequence as an actual bias voltage via a high-frequency digital-to-analog converter (DAC), and feeds it into a nanosecond-level response analog hardware comparator, using the system ground zero-volt level as the zero-level reference line for comparison. This ensures high-speed response while avoiding the time delay caused by pure software polling. When the voltage of the oscillation trajectory changes from positive to negative or from negative to positive, crossing the zero-level reference line, the comparator's output state flips. The system identifies the intersection point of the oscillation trajectory by capturing the precise moment of this flip signal.

[0138] Finally, based on the newly identified intersection point and the extracted periodic features, the system calculates and predicts the physical time point at which the next transient torsional phase difference waveform crosses zero. Since the vibration waveform approximates a periodic sine or cosine function, the time interval between two consecutive zero-crossings is half a period. Therefore, after capturing an intersection point, the occurrence time of the next intersection point can be accurately predicted. This predicted future time point is generated as the phase difference zero-crossing point. The calculation formula is:

[0139]

[0140] In the formula, It is the physical timestamp corresponding to the intersection of the oscillation trajectories most recently identified using a hardware comparator, in seconds. ); It is the vibration period calculated above, in seconds ( ); It is the final calculated zero-crossing point of the phase difference, which is a specific future timestamp, in seconds. ).

[0141] For example, suppose the vibration of the drive system has become out of control, and the active suppression measures in step S5 cannot curb its divergence trend. The system obtains an amplitude safety threshold of 0.1 degrees. At a certain moment, the system detects that the amplitude of the transient torsional phase difference waveform has reached 0.12 degrees, exceeding the amplitude safety threshold, and therefore this step is triggered.

[0142] The system immediately began continuously tracking the oscillation trajectory of the transient torsional phase difference waveform and extracting its periodic features. Using a peak detection algorithm, the system identified two consecutive positive peaks that occurred at the system timestamps. Seconds and Seconds. The vibration period is calculated based on this: Second.

[0143] Meanwhile, the system's hardware comparator cross-references the oscillation trajectory with the zero-level reference line. (System timestamp) At 10:00, the output of the hardware comparator flips, indicating that the system has identified the intersection of an oscillation trajectory.

[0144] After obtaining the latest intersection position and periodic characteristics, the system immediately calculates the next physical time point at which the transient torsional phase difference waveform crosses zero level. Substituting into the formula: Second.

[0145] Calculations show that the moment of minimum torsional stress inside the next drive shaft will occur precisely at system time 12.542 seconds. The system therefore generates a zero-crossing phase difference of 12.542 seconds. This highly precise timing will be passed to the next step to trigger the final mechanical protection action.

[0146] S7. Generate a zero-delay physical brake command based on the phase difference crossing zero point, and control the mechanical brake to perform mechanical braking action at the system timestamp corresponding to the phase difference crossing zero point.

[0147] In a specific embodiment of the present invention, a zero-delay physical brake command is generated based on the phase difference zero-crossing point, and the mechanical brake is controlled to perform mechanical braking action at the system timestamp corresponding to the phase difference zero-crossing point. This includes: obtaining the current system time and the action execution delay of the mechanical brake, calculating the braking delay time based on the difference between the phase difference zero-crossing point and the current system time, and deducting the action execution delay.

[0148] The system acquires the emergency mechanical braking trigger signal, generates a zero-delay physical brake command using the braking delay time, and actively intercepts the emergency mechanical braking trigger signal.

[0149] Send a zero-delay physical brake command to the mechanical brake to control the mechanical brake to perform a physical engagement action at the physical moment corresponding to the zero point of the phase difference.

[0150] Specifically, this step is the final execution stage of the entire protection strategy. Its goal is to transform the optimal braking time calculated in step S6 into a preset physical control of the mechanical brake, ensuring that emergency braking is performed at the absolute instant when the torsional stress of the drive shaft is minimal, thereby reducing the risk of secondary damage to the mechanical structure.

[0151] The implementation process begins with precise time calculation. After generating the future timestamp of the phase difference zero-crossing point in step S6, the system immediately acquires the current system time with high precision. By calculating the difference between the phase difference zero-crossing point and the current system time, and subtracting the inherent action execution delay of the mechanical brake, a waiting time is obtained, namely the braking delay time (i.e., the actual command trigger delay). This delay time is crucial for achieving synchronous braking. Its calculation formula is as follows:

[0152]

[0153] In this formula, The zero-crossing point of the phase difference generated in step S6 is an absolute timestamp, measured in seconds. ); This is the current system time when this calculation was performed, also a high-precision absolute timestamp, in seconds. ); The pre-acquired execution delay of the mechanical brake, in seconds ( ); This is the calculated braking delay time, in seconds. It indicates how much longer it will take to send the brake command before the mechanical engagement precisely reaches the optimal braking point.

[0154] Next, the system enters a standby state, awaiting an external or internal emergency stop request. When the system receives an emergency mechanical brake trigger signal, such as from an operator pressing an emergency stop button or from a severe fault signal detected by another sensor, the protection logic of this invention will play its core role. The system will actively intercept this original emergency mechanical brake trigger signal, preventing it from directly triggering the brake to act immediately. Instead, the system uses the previously calculated braking delay time to generate a completely new command, namely a zero-delay physical brake command. This command contains a timer whose timing duration is precisely set to the aforementioned calculated braking delay time to compensate for the dead time of mechanical action.

[0155] Finally, this precisely designed zero-delay physical brake command is sent to the controller of the mechanical brake. The mechanical brake is a device that achieves physical locking through friction pads or electromagnetic force. Upon receiving the command, the brake controller does not immediately execute the action but instead starts a timer embedded in the command. Only after the timer expires, i.e., after the braking delay time has elapsed, does the controller drive the brake to perform the physical engagement action. Because the time calculation and transmission delay of the entire process are precisely controlled at the microsecond level, the end of the timer corresponds precisely to the zero-crossing point of the phase difference predicted in step S6. Therefore, the mechanical brake performs the physical engagement action at the absolute instant when the torsional stress inside the drive shaft is almost zero, avoiding severe mechanical damage such as drive shaft shear fracture that could occur if sudden braking occurs at the peak torque.

[0156] For example, continuing from step S6, the system has calculated that the next phase difference zero crossing will occur at the system timestamp. Second.

[0157] After generating this timestamp, the system immediately obtains the current system time, assuming it is currently [time missing]. Seconds. The system obtains the mechanical brake's action execution delay based on factory preset parameters: =0.008 seconds. The system calculates the actual instruction trigger delay (i.e., the time to wait from the current moment) based on this: 0.003 seconds.

[0158] Calculations show that to compensate for the dead zone, the system must send an electrical brake command 3 milliseconds after the current moment. This command is generated at 12.531 seconds and incorporates a 3-millisecond countdown timer, which resets to zero and excites the coil at 12.534 seconds. After 8 milliseconds of mechanical displacement, the brake pads engage precisely at 12.542 seconds, accurately corresponding to the physical zero-crossing point of dynamic stress. Because braking occurs at the zero-crossing point, it avoids the transient superposition of the resonant phase peak and the braking impact load, preventing severe mechanical damage such as drive shaft shear fracture that could occur with sudden braking at the torque peak.

[0159] The zero-delay physical brake command was immediately sent to the mechanical brake. The brake controller started a 3-millisecond hardware countdown timer at 12.534 seconds (the moment the command was generated). The timer ran precisely in the background, and when it reached zero, the corresponding system time was exactly [time missing]. At this specified moment, the brake controller outputs a high-power signal to drive the electromagnetic brake coil, causing it to perform a mechanical braking action and achieve stable locking. After 8 milliseconds of mechanical action, the brake pads engage at exactly 12.542 seconds, precisely corresponding to the zero point of the physical dynamic stress. The entire emergency braking process is smooth and safe, successfully protecting the equipment while avoiding secondary damage caused by improper braking timing.

[0160] Reference Figure 2 The second aspect of the present invention provides a transient resonance avoidance system for a drive shaft based on phase difference, comprising: an absolute phase difference generation module, a stiffness degradation index generation module, a speed avoidance restricted area control module, a transient torsional phase difference waveform presentation module, a physical torque interference module, a phase difference zero-crossing point generation module, and a mechanical braking action execution module.

[0161] The absolute phase difference generation module is connected to the stiffness degradation index generation module, which is connected to the speed avoidance restricted area control module. Both the absolute phase difference generation module and the speed avoidance restricted area control module are connected to the transient torsional phase difference waveform presentation module. The transient torsional phase difference waveform presentation module is connected to the physical torque interference module. The transient torsional phase difference waveform presentation module is connected to the phase difference zero-crossing point generation module, which is connected to the mechanical braking action execution module.

[0162] The absolute phase difference generation module collects the rotational pulse signals from the power input end and the load output end of the drive shaft, extracts the physical time difference between the two rotational pulse signals, and converts the physical time difference into an absolute phase difference.

[0163] The stiffness degradation index generation module extracts the absolute phase difference under steady-state load conditions to construct the static phase difference baseline for the current service cycle. Combined with the initial static phase difference baseline from the initial manufacturing cycle, it assesses the degree of physical torsional stiffness degradation of the drive shaft based on the rate of change of the static phase difference baseline, and generates a stiffness degradation index.

[0164] The speed avoidance restricted area control module uses the stiffness degradation index to algebraically calculate the critical resonance speed after drift, and reconstructs the speed avoidance restricted area of ​​the underlying control program based on the critical resonance speed.

[0165] The transient torsional phase difference waveform presentation module monitors the absolute phase difference in real time under normal operating speed, obtains the real-time fluctuation sequence of the absolute phase difference, performs envelope analysis on the real-time fluctuation sequence, and extracts the oscillation segment with the envelope slope greater than zero and reaching the preset time threshold as the transient torsional phase difference waveform exhibiting divergent oscillation characteristics.

[0166] The physical torque interference module generates a high-frequency anti-phase current with a phase difference of half a cycle based on the transient torsional phase difference waveform. This anti-phase high-frequency compensation current is injected into the underlying current loop of the motor controller, generating an electromagnetic reverse torque to physically interfere with the drive shaft.

[0167] The phase difference zero-crossing point generation module obtains the amplitude safety threshold. When the amplitude of the transient torsional phase difference waveform exceeds the amplitude safety threshold, it continuously tracks the oscillation trajectory of the transient torsional phase difference waveform, calculates the physical time node when the transient torsional phase difference waveform crosses the zero level, and generates the phase difference zero-crossing point.

[0168] The mechanical braking action execution module generates a zero-delay physical brake command based on the phase difference zero-crossing point, and controls the mechanical brake to execute the mechanical braking action at the system timestamp corresponding to the phase difference zero-crossing point.

[0169] The above content is merely an example and illustration of the concept of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described, or use similar methods to replace them, as long as they do not deviate from the concept of the invention or exceed the scope defined by the present invention, and all such modifications and additions should fall within the protection scope of the present invention.

Claims

1. A method for avoiding transient resonance of a drive shaft based on phase difference, characterized in that, include: S1. Acquire the rotational pulse signals from the power input end and the load output end of the drive shaft, extract the physical time difference between the two rotational pulse signals, and convert the physical time difference into an absolute phase difference; S2. Under steady-state load conditions, extract the absolute phase difference to construct the static phase difference baseline for the current service cycle. Combine it with the initial static phase difference baseline of the initial manufacturing cycle. Evaluate the degree of physical torsional stiffness degradation of the drive shaft based on the rate of change of the static phase difference baseline and generate a stiffness degradation index. S3. Use the stiffness degradation index to algebraically calculate the critical resonance speed after drift, and reconstruct the speed avoidance zone of the underlying control program based on the critical resonance speed. S4. Under normal operating speed, monitor the absolute phase difference in real time, obtain the real-time fluctuation sequence of the absolute phase difference, perform envelope analysis on the real-time fluctuation sequence, and extract the oscillation segment with the envelope slope greater than zero and reaching the preset time threshold as the transient torsional phase difference waveform exhibiting divergent oscillation characteristics. S5. Based on the transient torsional phase difference waveform, generate a reverse high-frequency compensation current with a phase difference of half a cycle, inject the reverse high-frequency compensation current into the bottom current loop of the motor controller, and generate an electromagnetic reverse torque to physically interfere with the drive shaft. S6. Obtain the amplitude safety threshold. When the amplitude of the transient torsional phase difference waveform exceeds the amplitude safety threshold, continuously track the oscillation trajectory of the transient torsional phase difference waveform, calculate the physical time node when the transient torsional phase difference waveform crosses the zero level, and generate the phase difference zero crossing point. S7. Generate a zero-delay physical brake command based on the phase difference crossing zero point, and control the mechanical brake to perform mechanical braking action at the system timestamp corresponding to the phase difference crossing zero point.

2. The method for avoiding transient resonance of a drive shaft based on phase difference according to claim 1, characterized in that, The process involves acquiring rotational pulse signals from the power input end and load output end of the drive shaft, extracting the physical time difference between the two rotational pulse signals, and converting the physical time difference into an absolute phase difference, including: Collect rotational pulse signals from the power input end and the load output end of the drive shaft; Edge trigger detection of the rotating pulse signal is performed with nanosecond-level precision to extract the physical time difference between the two rotating pulse signals; Obtain the current operating speed of the drive shaft, and convert the physical time difference proportionally to the current operating speed to generate an absolute phase difference.

3. The method for avoiding transient resonance of a drive shaft based on phase difference according to claim 1, characterized in that, Under steady-state load conditions, the absolute phase difference is extracted to construct the static phase difference baseline for the current service cycle. Combined with the initial static phase difference baseline from the initial manufacturing cycle, the degree of physical torsional stiffness degradation of the drive shaft is assessed based on the rate of change of the static phase difference baseline, generating a stiffness degradation index, including: Obtain the time window parameters, extract the average absolute phase difference within the time window parameters under steady-state load conditions, and construct a static phase difference baseline; Obtain the initial static phase difference baseline of the initial manufacturing cycle, calculate the ratio of the difference between the static phase difference baseline of the current service cycle and the initial static phase difference baseline, and generate the baseline drift rate. Obtain the material mechanics degradation model, input the baseline drift rate into the material mechanics degradation model for mapping transformation, evaluate the degree of physical torsional stiffness degradation of the drive shaft, and generate stiffness degradation index.

4. The method for avoiding transient resonance of a drive shaft based on phase difference according to claim 1, characterized in that, The process of algebraically solving the critical resonance speed after drift using the stiffness degradation index, and reconstructing the speed avoidance zone of the underlying control program based on the critical resonance speed, includes: The initial natural frequency of the drive shaft is obtained, and the square root proportionality of the initial natural frequency is calculated using the stiffness degradation index to generate the critical resonance speed after drift. The upper and lower limits of the resonance frequency are determined based on the critical resonance speed, and the speed avoidance interval is generated. Obtain the parameter register of the underlying control program, overwrite the speed avoidance range into the parameter register, and reconstruct the speed avoidance no-go zone of the underlying control program.

5. The method for avoiding transient resonance of a drive shaft based on phase difference according to claim 1, characterized in that, The process involves real-time monitoring of the absolute phase difference at normal operating speed, acquiring a real-time fluctuation sequence of the absolute phase difference, performing envelope analysis on the real-time fluctuation sequence, and extracting oscillation segments with an envelope slope greater than zero and reaching a preset time threshold as transient torsional phase difference waveforms exhibiting divergent oscillation characteristics. This includes: Under normal operating speed, the absolute phase difference is monitored in real time to obtain the real-time fluctuation sequence of the absolute phase difference; Envelope analysis is performed on real-time fluctuation sequences to extract oscillating segments with an envelope slope greater than zero and continuously increasing. The oscillation segment is used as a transient torsional phase difference waveform exhibiting divergent oscillation characteristics.

6. The method for avoiding transient resonance of a drive shaft based on phase difference according to claim 1, characterized in that, The process involves generating a reverse high-frequency compensation current with a phase difference of half a cycle based on the transient torsional phase difference waveform, injecting this reverse high-frequency compensation current into the underlying current loop of the motor controller, and generating an electromagnetic reverse torque to physically interfere with the drive shaft. This includes: Perform a Fast Fourier Transform on the transient torsional phase difference waveform to extract the dominant frequency and instantaneous phase of the transient torsional phase difference waveform; Based on the main frequency and instantaneous phase, an anti-phase high-frequency compensation current with a phase difference of half a cycle is generated; Injecting a reverse high-frequency compensation current into the bottom current loop of the motor controller generates an electromagnetic reverse torque that physically interferes with the drive shaft.

7. The method for avoiding transient resonance of a drive shaft based on phase difference according to claim 6, characterized in that, The process of injecting a reverse high-frequency compensation current into the bottom current loop of the motor controller to generate an electromagnetic reverse torque that physically interferes with the drive shaft includes: Obtain the basic drive current of the motor controller, and superimpose the inverted high-frequency compensation current with the basic drive current to generate a composite drive current; The motor rotor is driven by a composite drive current to generate an electromagnetic reverse torque; The electromagnetic reverse torque is transmitted to the torsional deformation region through the rigid connection of the drive shaft. The torsional resonance peak of the drive shaft is flattened by the physical antiphase interference between the electromagnetic reverse torque and the mechanical torsional stress.

8. The method for avoiding transient resonance of a drive shaft based on phase difference according to claim 1, characterized in that, The process of obtaining the amplitude safety threshold involves continuously tracking the oscillation trajectory of the transient torsional phase difference waveform when its amplitude exceeds the threshold, calculating the physical time point at which the transient torsional phase difference waveform crosses the zero level, and generating the phase difference zero-crossing point. This includes: Obtain the amplitude safety threshold. When the amplitude of the transient torsional phase difference waveform exceeds the amplitude safety threshold, continuously track the oscillation trajectory of the transient torsional phase difference waveform and extract the periodic characteristics of the oscillation trajectory. Obtain the zero-level baseline, and use a hardware comparator to cross-compare the oscillation trajectory with the zero-level baseline to identify the intersection point of the oscillation trajectory; Based on the intersection point and periodic characteristics, the physical time node at which the transient torsional phase difference waveform crosses the zero level is calculated, and the zero-crossing point of the phase difference is generated.

9. The method for avoiding transient resonance of a drive shaft based on phase difference according to claim 1, characterized in that, The step of generating a zero-delay physical brake command based on the phase difference zero-crossing point, and controlling the mechanical brake to execute the mechanical braking action at the system timestamp corresponding to the phase difference zero-crossing point, includes: Obtain the current system time and the action execution delay of the mechanical brake. Calculate the braking delay time based on the difference between the phase difference zero-crossing point and the current system time, and subtract the action execution delay. Obtain the emergency mechanical braking trigger signal, generate a zero-delay physical brake command using the braking delay time, and actively intercept the emergency mechanical braking trigger signal; Send a zero-delay physical brake command to the mechanical brake to control the mechanical brake to perform a physical engagement action at the physical moment corresponding to the zero point of the phase difference.

10. A transient resonance avoidance system for a drive shaft based on phase difference, characterized in that, include: The absolute phase difference generation module collects the rotational pulse signals from the power input end and the load output end of the drive shaft, extracts the physical time difference between the two rotational pulse signals, and converts the physical time difference into an absolute phase difference. The stiffness degradation index generation module extracts the absolute phase difference under steady-state load conditions to construct the static phase difference baseline for the current service cycle. Combined with the initial static phase difference baseline of the initial manufacturing cycle, the module evaluates the degree of physical torsional stiffness degradation of the drive shaft based on the rate of change of the static phase difference baseline and generates a stiffness degradation index. The speed avoidance no-go zone control module uses the stiffness degradation index to algebraically calculate the critical resonance speed after drift, and reconstructs the speed avoidance no-go zone of the underlying control program based on the critical resonance speed. The transient torsional phase difference waveform presentation module monitors the absolute phase difference in real time under normal operating speed, obtains the real-time fluctuation sequence of the absolute phase difference, performs envelope analysis on the real-time fluctuation sequence, and extracts the oscillation segment with the envelope slope greater than zero and reaching the preset time threshold as the transient torsional phase difference waveform exhibiting divergent oscillation characteristics. The physical torque interference module generates a reverse high-frequency compensation current with a phase difference of half a cycle based on the transient torsional phase difference waveform. The reverse high-frequency compensation current is injected into the bottom current loop of the motor controller to generate an electromagnetic reverse torque to physically interfere with the drive shaft. The phase difference zero-crossing point generation module obtains the amplitude safety threshold. When the amplitude of the transient torsional phase difference waveform exceeds the amplitude safety threshold, it continuously tracks the oscillation trajectory of the transient torsional phase difference waveform, calculates the physical time node when the transient torsional phase difference waveform crosses the zero level, and generates the phase difference zero-crossing point. The mechanical braking action execution module generates a zero-delay physical brake command based on the phase difference zero-crossing point, and controls the mechanical brake to execute the mechanical braking action at the system timestamp corresponding to the phase difference zero-crossing point.

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