Ultrasonic jade grinding machine and amplitude self-adaptive control method thereof

Abstract

According to the ultrasonic jade grinding machine and the amplitude self-adaptive control method thereof, whether the current working frequency is in a risk frequency band with the maximum stress frequency center fc of a lock head as the center or not is judged, the maximum amplitude is actively limited, the frequency change rate criterion based on daily use data is introduced, and on the premise of not depending on a temperature sensor, the maximum stress frequency center fc of the lock head is judged to be in the risk frequency band; a short-time frequency change rate is calculated through a sliding window and is compared with a normal drift rate baseline of history learning, a hysteresis and continuous window threshold is adopted for triggering, power or duty ratio is temporarily reduced after triggering, a triggering frequency band is memorized as a limited frequency band, a time or frequency attenuation mechanism is set, long-term excessive conservative is avoided, and the time or frequency attenuation efficiency is improved. And when the change rate returns to normal, gradual recovery is carried out according to asymmetric speed limit, and the risks of overheat of the lock and out-of-control power are remarkably reduced in cooperation with self-learning dynamic updating and redundancy protection of fc, and serious frequency drift and oilstone burning are avoided.

Description

Technical Field

[0001] This application relates to the field of electronic digital data technology, specifically to an ultrasonic jade polishing machine and its amplitude adaptive control method. Background Technology

[0002] Ultrasonic jade polishing machines achieve efficient and precise polishing through ultrasonic longitudinal vibration. Fiber oilstones wear down and shorten during use, resulting in a reduction in the system's equivalent length and an increase in resonant frequency. When the lock cylinder is located near a mode node, stress concentration and micro-friction occur, leading to rapid heat generation. Due to the lack of effective monitoring of the lock cylinder temperature, users often have to passively reduce the amplitude after sensing overheating or the system reporting detuning, resulting in the following problems: Local overheating of the lock head leads to a vicious cycle of frequency drift and impedance changes; burns on the surface of the whetstone cause adhesion degradation and may trigger power runaway; and operators need to intervene frequently, affecting continuous processing efficiency and quality consistency. Therefore, there is an urgent need for a control scheme that actively limits the amplitude near the maximum stress position of the lock head and can adaptively update the risk frequency band as the oilstone shortens. This scheme is used to actively avoid the heating frequency band when the resonant frequency drifts due to changes in the length of the oilstone, thereby preventing the lock head from overheating, severe frequency drift, oilstone burnout, and power runaway, and achieving continuous and stable processing. Summary of the Invention

[0003] To address the problems existing in the prior art, this application aims to provide an ultrasonic jade polishing machine and its amplitude adaptive control method. By determining whether the current operating frequency is located in the risk band centered on the maximum stress frequency of the lock head, the amplitude is divided into bands and gradually managed to suppress overheating and power runaway of the lock head. At the same time, processing efficiency and user experience are taken into account. Furthermore, a frequency change rate criterion based on daily usage data is introduced to identify the operating state close to the heating frequency band without relying on temperature sensors. Adaptive adjustment of frequency and power output is then performed to achieve feedforward avoidance and online self-learning.

[0004] The ultrasonic jade polishing machine and its amplitude adaptive control method described in this application include: S101. Obtain the current operating frequency f and the user-defined upper limit of amplitude Au; S102. Determine the center of the maximum stress frequency of the lock head, fc, and define the first frequency band B1 and the second frequency band B2 based on the center frequency, wherein the bandwidth of the second frequency band B2 is greater than that of the first frequency band B1. S103. Based on the relationship between the current operating frequency f and the center of the maximum stress frequency fc of the lock head, calculate the upper limit of the system amplitude A(f): If f is located within the first frequency band B1, then A(f) is equal to the first amplitude value A1; If f is located in the second frequency band B2 and not in the first frequency band B1, then A(f) is monotonically interpolated between the first amplitude value A1 and the second amplitude value A2 according to the magnitude of the frequency difference, where A2 is greater than A1; If f is outside the second frequency band B2, then A(f) is equal to the second amplitude value A2; The user-defined upper limit of amplitude Au is compared with the upper limit of system amplitude A(f), and the smaller of the two values ​​is taken as the actual output amplitude Aout; S104. The actual output amplitude Aout is subjected to slope limiting and smoothing filtering, and then output to the power amplifier module to drive the transducer. S105. Based on statistical analysis of historical operating data, the center of the maximum stress frequency fc of the lock head is adaptively updated. S106. During operation, a sliding window is used to calculate the short-time frequency change rate, and the short-time frequency change rate is compared with the normal drift rate baseline learned based on historical operation data. When the short-time frequency change rate exceeds a preset threshold and meets the hysteresis and duration thresholds, the system is determined to be close to the lock head heating frequency band, and one or more countermeasures including output derating and cooling intervals are executed, and the frequency band that triggered the determination is recorded as a restricted frequency band. S107. Continuously monitor power or temperature parameters and execute redundant protection control when an abnormality is detected.

[0005] Preferably, the upper limit of the system amplitude A(f) varies linearly between the first amplitude value A1 and the second amplitude value A2 according to the magnitude of the frequency difference.

[0006] Preferably, the upper limit of the system amplitude A(f) varies nonlinearly between the first amplitude value A1 and the second amplitude value A2 according to the magnitude of the frequency difference, and the nonlinear variation is interpolated using a quadratic curve or an S-shaped curve.

[0007] Preferably, the rise rate and fall rate of the actual output amplitude Aout are respectively set with maximum change rates Rup and Rdown to limit the slope, and the limit value of the fall rate Rdown is greater than or equal to the limit value of the rise rate Rup.

[0008] Preferably, the first frequency band B1 and the second frequency band B2 are symmetrical bandwidths, with the center of the maximum stress frequency fc of the lock head as the center, and the first width Δ1 and the second width Δ2 extending to both sides respectively, wherein the second width Δ2 is greater than the first width Δ1.

[0009] Preferably, the first frequency band B1 and the second frequency band B2 are asymmetrical bandwidths, and different widths are defined on the left and right sides of the center fc of the maximum stress frequency of the lock head, wherein the left width Δ2- of the second frequency band is greater than the left width Δ1- of the first frequency band, and the right width Δ2+ of the second frequency band is greater than the right width Δ1+ of the first frequency band.

[0010] Preferably, the method for adaptively updating the center of the maximum stress frequency fc of the lock head includes: The mapping estimation is performed based on the calibration relationship between the length of the oilstone and the resonant frequency, or the frequency range corresponding to the peak value of the temperature rise slope is identified based on the frequency sweep test.

[0011] Preferably, the triggering condition for the determination system to approach the lock's heating frequency band is specifically as follows: The short-time frequency change rate continuously exceeds the preset threshold of the normal drift rate baseline learned from historical operating data for at least Tmin consecutive sliding windows.

[0012] Preferably, the redundancy protection control includes: performing additional derating when the detected temperature exceeds a first threshold T1; When the temperature exceeds the higher second threshold T2, shutdown protection is executed, and the output is actively limited when a sudden change in active power is detected to prevent power runaway.

[0013] The ultrasonic jade polishing machine and its amplitude adaptive control method described in this application have the following advantages: It actively limits the amplitude within the maximum stress frequency band of the locking head, significantly suppressing local heating and avoiding severe frequency drift and oilstone burnout. It employs feedforward protection based on frequency band identification and frequency change rate to avoid the hysteresis of "derating after overheating," resulting in high stability during continuous processing. Combined with gradual recovery and slope limitation, it avoids uneven processing textures or mechanical impacts caused by sudden amplitude changes. It supports superimposed constraints of user upper limits and system upper limits, balancing processing efficiency and equipment safety. It can dynamically update the fc (frequency control unit) through self-learning and memorize the limited frequency band, allowing for long-term adaptation to different oilstones, clamping methods, and working conditions. It has strong versatility and can still achieve early warning based on frequency change behavior even in temperature sensor-free solutions, reducing misjudgments and overly conservative approaches. Attached Figure Description

[0014] Figure 1 This application describes the process of an ultrasonic jade polishing machine and its amplitude adaptive control method. Figure 1 ; Figure 2 This application describes the process of an ultrasonic jade polishing machine and its amplitude adaptive control method. Figure 2 ; Figure 3 This application describes the process of an ultrasonic jade polishing machine and its amplitude adaptive control method. Figure 3 . Detailed Implementation

[0015] like Figures 1-3 As shown in this application, an ultrasonic jade polishing machine and its amplitude adaptive control method are described.

[0016] The ultrasonic jade polishing machine and its amplitude adaptive control method described in this application include: S101. Obtain the current operating frequency f and the user-defined upper limit of amplitude Au; S102. Determine the center of the maximum stress frequency of the lock head, fc, and define the first frequency band B1 and the second frequency band B2 based on the center frequency, wherein the bandwidth of the second frequency band B2 is greater than that of the first frequency band B1. S103. Based on the relationship between the current operating frequency f and the center of the maximum stress frequency fc of the lock head, calculate the upper limit of the system amplitude A(f): If f is located within the first frequency band B1, then A(f) is equal to the first amplitude value A1; If f is located in the second frequency band B2 and not in the first frequency band B1, then A(f) is monotonically interpolated between the first amplitude value A1 and the second amplitude value A2 according to the magnitude of the frequency difference, where A2 is greater than A1; If f is outside the second frequency band B2, then A(f) is equal to the second amplitude value A2; The user-defined upper limit of amplitude Au is compared with the upper limit of system amplitude A(f), and the smaller of the two values ​​is taken as the actual output amplitude Aout; S104. The actual output amplitude Aout is subjected to slope limiting and smoothing filtering, and then output to the power amplifier module to drive the transducer. S105. Based on statistical analysis of historical operating data, the center of the maximum stress frequency fc of the lock head is adaptively updated. S106. During operation, a sliding window is used to calculate the short-time frequency change rate, and the short-time frequency change rate is compared with the normal drift rate baseline learned based on historical operation data. When the short-time frequency change rate exceeds a preset threshold and meets the hysteresis and duration thresholds, the system is determined to be close to the lock head heating frequency band, and one or more countermeasures including output derating and cooling intervals are executed, and the frequency band that triggered the determination is recorded as a restricted frequency band. S107. Continuously monitor power or temperature parameters and execute redundant protection control when an abnormality is detected.

[0017] like Figure 1 As shown, an ultrasonic jade polishing machine for use in this application includes: Transducer 10: Used to convert electrical signals into mechanical longitudinal ultrasonic vibration; Amplitude transformer 20 (optional): used for amplitude transformation and energy transfer; Lock head 30: connects the metal end to the fiber oilstone 40; Power amplification module 50: controlled output of excitation voltage or current, supporting constant amplitude or constant power operation modes; Controller 60: represented as MCU / DSP / FPGA + MCU, including ADC, PWM, DAC interfaces, and connected to the sensor group 70; Sensor group 70: includes current, voltage, phase, and amplitude sampling channels.

[0018] In the frequency band limiting strategy of an embodiment, the controller 60 periodically obtains the current operating frequency f, such as the resonant frequency tracked by the phase-locked loop or the operating frequency specified by the MCU / FPGA, and maintains the maximum stress frequency center fc of the lock head and the bandwidth parameters Δ1, Δ2 and the amplitude upper limits A1, A2, and defines the piecewise upper limit function A(f): If |f fc| ≤ Δ1: A(f) = A1; If Δ1 < |f fc| ≤ Δ2: A(f) = A1 + (A2 A1) · (|f fc| Δ1) / (Δ2 Δ1); If |f fc| > Δ2: A(f) = A2; The actual output amplitude Aout = min{Au, A(f)}, where Au is the upper limit set by the user or the factory default upper limit; To avoid shocks caused by rapid changes, a slope limit and first-order filtering are applied to Aout, including limiting the rising or falling rate not exceeding Rup, Rdown respectively; Typical parameter settings: fc = 25 kHz, Δ1 = 0.5 kHz, Δ2 = 1.0 kHz, A1 = 0.70 · Amax, A2 = 1.00 · Amax; When Au < A2, it does not exceed the user's upper limit; In addition, to improve adaptability, an asymmetric bandwidth Δ1 or Δ1 +, Δ2 or Δ2 + can be selected; At this time, when f < fc, it is calculated according to the left bandwidth, and when f > fc, it is calculated according to the right bandwidth, used to reflect the asymmetry of the actual heating area, and the linear / non-linear interpolation of the limiting function A(f) remains unchanged.

[0019] In one embodiment of fc identification and adaptive update, to adapt to changes in oilstone length, the system provides one or more combinations of the following fc update methods: Among them, the calibration mapping method is to establish the relationship between the effective length L of the oilstone and the resonant frequency fres during factory or maintenance, and combine it with the position of the lock head structure to obtain the fc(L) mapping corresponding to the lock head node. During operation, fc is back-calculated based on the estimated L or fres. Among them, the no-load power method: Perform sonic tests under cold conditions at different lengths of the oilstone, record the relationship between no-load power and length or frequency, and estimate fc accordingly; The data accumulation and baseline learning used in adaptive criterion and response based on frequency change rate are represented as follows: During long-term operation, frequency-time series are recorded, short-term frequency change rate is calculated using a sliding window, and a statistical baseline for normal drift rate is established by median filtering or outlier removal. The system is self-updated according to environmental changes and oilstone replacement. During the cold start phase, a conservative threshold and small step strategy are adopted. Among them, the trigger determination is: when the short-term frequency change rate exceeds the threshold relative to the historical baseline and the duration exceeds the threshold, it is marked as "approaching the heat generation frequency band"; At the same time, the confidence level is improved by combining the small change trend of impedance or phase, and if available, cross-validation is carried out using power or temperature side information. Adaptive execution derating control: temporarily reduce power, duty cycle, or duty cycle pulse width, and introduce intermittent cooling if necessary; Among them, frequency band memory: the trigger location and its neighborhood are recorded as restricted frequency bands, which, together with the factory calibration data, are used as the FC derating frequency; Among them, gradual recovery: after the rate of change returns to normal, it performs smooth recovery by pressing Rup and Rdown to prevent repeated triggering.

[0020] In one implementation, power protection prevents power runaway by detecting sudden changes in active power; Mismatch detection automatically reduces the amplitude and performs a self-test when there is a sudden change in impedance or an abnormal phase. The user limit will be set to never exceed Au under any circumstances.

[0021] like Figure 3 As shown, the specific steps in the control process are as follows: The system samples voltage and current and calculates amplitude, or directly measures the operating amplitude through a ceramic plate to maintain constant amplitude control. Based on the latest fc, Δ1, and Δ2, it calculates the upper limit of constant amplitude control A(f), calculates Aout=min{Au,A(f)}, applies slope limits and filtering, and outputs PWM or drive commands to the power amplifier module to achieve the target amplitude. Based on the frequency change rate and historical baseline, as well as impedance or phase information, it assesses whether it is close to the heating frequency band. If the triggering condition is met, it performs amplitude derating and includes the triggering frequency band in the restricted frequency band record. If the update condition is met, it performs fc evaluation and fine-tuning, continuously monitors power or impedance, and performs redundancy protection.

[0022] Furthermore, the specific steps in the control process also include: The system samples voltage and current signals in real time and calculates the current operating amplitude, or directly measures the amplitude through a ceramic plate sensor, which is used to maintain a constant amplitude control closed loop. Based on the latest self-learned maximum stress frequency center fc of the lock head and its associated frequency band parameters Δ1 and Δ2, the upper limit of the system amplitude A(f) related to the current frequency is calculated. The user-defined upper limit of amplitude Au is compared with the above system upper limit A(f), and the smaller value between the two is taken as the actual output amplitude Aout. A slope limit and smoothing filter are applied to Aout to avoid sudden output changes. Based on the processed Aout, a corresponding PWM or drive command is generated and output to the power amplifier module; The system calculates the short-time frequency change rate based on a sliding window, and combines the normal drift rate baseline obtained from historical learning with real-time impedance or phase information to comprehensively assess whether it is close to the frequency band at which the latch is prone to overheating. If the preset triggering conditions are met, amplitude derating control is immediately executed, and the currently triggered frequency band is recorded in the restricted frequency band set for continued control of priority avoidance. Furthermore, if the system determines that the parameter update conditions have been met, it will initiate a re-evaluation and dynamic fine-tuning of fc. Throughout the operation, the system continuously monitors key power and impedance parameters, and executes a redundancy protection strategy once an anomaly is detected, thereby ensuring stable and reliable operation of the equipment.

[0023] In one embodiment, the system default parameters are fc=25kHz, Δ1=0.5kHz, Δ2=1.0kHz, A1=70%·Amax, A2=100%·Amax; When f∈[24.5,25.5]kHz, the maximum amplitude limit is 70%; It recovers linearly from 70% to 100% within the range of [24.0, 24.5) ∪ (25.5, 26.0] kHz; Beyond [24.0, 26.0] kHz, allow up to 100% (not exceeding Au); In actual operation, users can set Au to 80%, then the system will further limit A(f) to no more than 80%; In the same embodiment, the self-learning module updates the normal drift rate baseline with data from the past week of operation: If the short-term rate of change exceeds the baseline mean + 3σ within 3 consecutive windows and remains at least tmin, then amplitude derating is triggered. When the fc update obtained by the self-learning module causes the new restricted frequency band to overlap or split with the historical record, the bands are merged and the width is updated by weighted average. The derating is automatically lifted when the minimum weight threshold is exceeded.

[0024] In one specific embodiment, the ultrasonic jade polishing machine of the present invention and Figure 1 As shown, it includes a transducer 10, an optional amplitude transformer 20, a locking head 30, a fiber oilstone 40, a power amplifier module 50, a controller 60, and a sensor group 70. The amplitude adaptive control method is executed through the controller 60, and the process is consistent with... Figure 3 As shown, the specific implementation process is as follows: In this embodiment, the controller 60 is configured to perform the following operations: First, the current operating frequency f of the system is acquired in real time, and a key parameter is dynamically maintained during operation: the center of the maximum stress frequency of the lock head, fc. Centered on fc, two risk bands are defined: First frequency band B1=[fc Δ1,fc+Δ1] and the second frequency band B2=[fc Δ2,fc+Δ2], where Δ2>Δ1>0; Based on the relationship between the operating frequency f and the center frequency fc, the upper limit of the system's maximum output amplitude A(f) is set: If f is within the first frequency band B1, then A(f) is strictly limited to a lower preset value A1; If f is within the second frequency band B2 but not within B1, then A(f) lies between A1 and a higher preset value A2, based on the absolute value of the frequency difference |f fc| is used for monotonical interpolation calculation in the interval [Δ1, Δ2]; If f is outside the second frequency band B2, then A(f) is allowed to reach the maximum value A2, and satisfies A1. <A2; The calculated upper limit of system amplitude A(f) is compared with the upper limit of amplitude Au set by the user, and the smaller value of the two is taken as the final actual output amplitude Aout, that is, Aout=min{Au,A(f)}; To ensure smooth operation, a slope limit is applied to Aout, limiting its maximum rising rate Rup and maximum falling rate Rdown respectively. Typically, Rdown is set to be greater than or equal to Rup. The signal is then smoothed and filtered before being output to the power amplifier module 50 to drive the transducer. Based on historical operating data, the controller 60 establishes a statistical baseline for the normal drift rate of the operating frequency, including the mean and standard deviation. During operation, a sliding window is used to calculate the short-time frequency change rate in real time and compare it with the baseline. When the short-time frequency change rate exceeds "baseline mean + K times standard deviation" for at least Tmin consecutive time windows and meets a certain hysteresis threshold, it is determined that the system is close to the lock-head heating frequency band. After the trigger is determined, the controller 60 will temporarily reduce the amplitude output and record the frequency of the trigger position and its neighborhood as a "restricted frequency band". The restricted frequency band has a time or number of pass attenuation mechanism, which will automatically narrow the range of influence or remove it as time goes by or the number of normal passes increases. When the short-term frequency change rate falls back to the normal baseline range, the system will gradually restore to the target output according to the set slope limit.

[0025] Preferably, the implementation method is as follows: The monotonic interpolation can be linear interpolation, specifically A(f) = A1 + (A2) A1)·(|f fc| Δ1) / (Δ2 Δ1); The monotonic interpolation can also employ nonlinear interpolation, such as quadratic interpolation or S-curve interpolation, to optimize the smoothness of the amplitude recovery process; Controller 60 supports multi-risk frequency band configuration, meaning multiple groups of {fc} can be defined. i ,Δ1 i ,Δ2 i A1 i The parameter set is designed to address the multiple vibration modes that the system may have or the multiple sensitive frequency regions that may appear after replacing parts. The first and second frequency bands can be configured with asymmetric bandwidths, that is: B1=[fc Δ1 ,fc+Δ1+]; B2=[fc Δ2 ,fc+Δ2+], where Δ2 >Δ1 >0, Δ2+>Δ1+>0; When f < fc, calculate according to the left bandwidth; when f > fc, calculate according to the right bandwidth, so as to more accurately match the asymmetry characteristics of the actual heating area; The memory of the restricted frequency band adopts a decay update mechanism based on time or the number of passes, and is automatically released when the decay reaches the preset weight threshold; If the same area is triggered multiple times, record it by merging according to the union, and update the width of this frequency band in a weighted average manner; As a further redundant protection, when the controller 60 detects that the temperature exceeds the threshold T1, it can perform additional derating operations, and when the temperature exceeds a higher threshold T2, it executes shutdown protection. At the same time, it continuously monitors the power, and actively limits the output when detecting a sudden change in the active power to prevent power out-of-control.

[0026] Furthermore, in the parameter example: In a specific working scenario, the system preset parameters are: fc = 25 kHz, Δ1 = 0.5 kHz, Δ2 = 1.0 kHz, A1 = 0.70 × Amax, A2 = 1.00 × Amax; When the working frequency f is within the range of [24.5, 25.5] kHz, the upper limit of the amplitude is limited to 70% of the maximum amplitude; Within the ranges of [24.0, 24.5 kHz and 25.5, 26.0] kHz, the upper limit of the amplitude linearly recovers from 70% to 100%; When the frequency exceeds [24.0, 26.0] kHz, the upper limit of the amplitude is allowed to reach 100%; If the user sets the upper limit Au to 80%, the final output amplitude of the system will not exceed 80%; The self-learning module updates the baseline according to the recent operation data. If the short-term frequency change rate exceeds "baseline mean + 3 times standard deviation" within 3 consecutive windows and lasts for at least the shortest time Tmin, trigger derating protection and update the relevant restricted frequency band records.

[0027] As Figures 1-3 As described above, this application determines whether the current working frequency is in the risk frequency band centered on the maximum stress frequency of the chuck, implements zoned amplitude limiting and gradual change management for the amplitude, suppresses chuck overheating and power out-of-control, takes into account processing efficiency and user experience, and introduces a frequency change rate criterion based on daily usage data. The specific implementation process of identifying the operating state close to the heating frequency band without relying on the temperature sensor and performing adaptive adjustment on the frequency and power output is as follows: The ultrasonic jade polishing machine of this embodiment, referring to Figure 1 , includes a transducer 10, a horn 20 (optional), a chuck 30, a fiber oilstone 40, a power amplification module 50, a controller 60, and a sensor group 70. The controller 60 uses an MCU and is responsible for executing the core control algorithm; The specific implementation process is as follows: This embodiment sets a set of typical control parameters: The center of the maximum stress frequency of the lock head is fc = 25kHz; The first frequency band bandwidth Δ1 = 0.5 kHz, and the second frequency band bandwidth Δ2 = 1.0 kHz; The corresponding upper limit of amplitude is A1 = 0.70 × Amax (Amax is the maximum amplitude capability of the system), and A2 = 1.00 × Amax; The user-defined amplitude limit Au is A2 by default, but users are allowed to adjust it downwards according to operating conditions. In the implementation of amplitude segmentation limiting and gradual control, the specific steps are as follows: The controller 60 continuously monitors and acquires the current operating frequency f of the system, and calculates and executes the following amplitude limiting strategy based on the relationship between f and fc: If f falls within the first frequency band B1 ([24.5, 25.5] kHz); The maximum allowable output amplitude A(f) of the system is then limited to A1 (70% of Amax); If f falls in the second frequency band B2 but does not belong to B1 [24.0, 24.5 kHz or 25.5, 26.0] kHz; Then A(f) is calculated by linear interpolation in the interval [0.5, 1.0] kHz based on |f-fc|; Specifically: A(f) = A1 + (A2 - A1) × (|f - fc| - Δ1) / (Δ2 - Δ1), so that the upper limit of the amplitude changes smoothly from A1 to A2; If f falls outside B2 (below 24.0kHz or above 26.0kHz), then A(f) equals A2; The controller compares the calculated system upper limit A(f) with the user-defined upper limit Au; The smaller of the two values ​​is taken as the final actual output amplitude command Aout, Aout=min{Au,A(f)}; To ensure smooth output, a slope limit is applied to Aout, including a rise rate not exceeding Rup and a fall rate not exceeding Rdown. Typically, Rdown is set to be greater than or equal to Rup. A first-order low-pass filter is then applied, and the processed command is output to the power amplifier module 50 to drive the transducer. The specific implementation of feedforward avoidance and self-learning based on the rate of frequency change is as follows: During the daily operation of the equipment, the controller 60 continuously records sequence data whose frequency changes over time; The sliding window algorithm is used to calculate the short-term frequency change rate, and a "normal drift rate baseline" is established through self-learning by statistical analysis (median filtering to exclude outliers). This baseline includes statistical features such as mean and standard deviation (σ). In the real-time control loop, the controller continuously calculates the current short-term frequency change rate and compares it with the above historical baseline. When the preset trigger criteria are met, for example, if the short-term frequency change rate exceeds "baseline mean + Kσ" (mean + 3σ) for Tmin consecutive calculation windows (3 windows), it is determined that the system operating frequency is approaching the risk band that causes the lock head to heat up significantly. Once the determination is successful, the controller immediately executes feedforward adaptive adjustment: In active derating and avoidance: temporarily reduce the drive power duty cycle or output amplitude, and introduce a brief intermittent pause to assist cooling, while attempting to shift the operating frequency in small steps in a safe direction; In frequency band memory and update: the frequency point that triggered the judgment and its surrounding area are recorded as a "restricted frequency band". This record will be integrated with the factory calibration data and used for the prediction and avoidance of risky frequency bands in subsequent control. This "restricted frequency band" is assigned a weight and has an attenuation mechanism. For example, its weight will decrease over time or the number of times the frequency band is passed normally will increase. When the weight is lower than the preset threshold, the record will be automatically released, thereby avoiding the control strategy from being overly conservative due to historical data. During gradual recovery: When the short-term frequency change rate is detected to fall back to the normal baseline range, the controller controls the output amplitude to smoothly and gradually recover to the target value according to the set slope limit (Rup / Rdown), ensuring the continuity of processing; The system also uses the frequency change rate data and trigger records, combined with the oilstone length estimation information, to dynamically fine-tune and update the estimated value of the maximum stress frequency center fc of the lock head for adaptive learning of parameters. Throughout the process, the controller 60 continuously monitors the system's active power, impedance, and phase (via the sensor group 70). If a power surge, severe impedance mismatch, or phase anomaly is detected, redundant protection control will be immediately executed, such as forcibly reducing the amplitude or initiating a system self-test to ensure equipment safety. Through the implementation of this embodiment, the system can intelligently identify and actively avoid the frequency band at risk of overheating of the lock head without the need for additional temperature sensors. It effectively suppresses overheating and power runaway through band limiting and gradual management, while taking into account processing efficiency and user experience, and achieves stable and adaptive ultrasonic polishing control.

[0028] For those skilled in the art, various other corresponding changes and modifications can be made based on the technical solutions and concepts described above, and all such changes and modifications should fall within the protection scope of the claims of this application.

Claims

1. An ultrasonic jade polishing machine and its amplitude adaptive control method, characterized in that, include: S101. Obtain the current operating frequency f and the user-defined upper limit of amplitude Au; S102. Determine the center of the maximum stress frequency fc of the lock head and use it as a reference. Define the first frequency band B1 and the second frequency band B2 respectively, wherein the bandwidth of the second frequency band B2 is greater than that of the first frequency band B1. S103. Calculate the upper limit of system amplitude A(f) based on the current operating frequency f and the center of the maximum stress frequency fc of the lock head: If f is located within the first frequency band B1, then A(f) is equal to the first amplitude value A1; If f is located in the second frequency band B2 and not in the first frequency band B1, then A(f) is monotonically interpolated between the first amplitude value A1 and the second amplitude value A2 according to the magnitude of the frequency difference, where A2 is greater than A1; If f is outside the second frequency band B2, then A(f) is equal to the second amplitude value A2; The user-defined upper limit of amplitude Au is compared with the upper limit of system amplitude A(f), and the smaller of the two values ​​is taken as the actual output amplitude Aout; S104. The actual output amplitude Aout is subjected to slope limiting and smoothing filtering, and then output to the power amplifier module. S105. Based on statistical analysis of historical operating data, the center of the maximum stress frequency fc of the lock head is adaptively updated. S106. During operation, a sliding window is used to calculate the short-time frequency change rate, and the short-time frequency change rate is compared with the normal drift rate baseline learned based on historical operation data. When the short-time frequency change rate exceeds the preset threshold and meets the hysteresis and duration thresholds, the system is determined to be close to the lock head heating frequency band, that is, to execute one or more countermeasures including output derating and cooling intervals, and to record the frequency band that triggered the determination as a restricted frequency band. S107. Continuously monitor power or temperature parameters and execute redundant protection control when an abnormality is detected.

2. The ultrasonic jade polishing machine and its amplitude adaptive control method according to claim 1, characterized in that, In S103, the upper limit of the system amplitude A(f) is linearly interpolated between the first amplitude value A1 and the second amplitude value A2 based on the magnitude of the frequency difference.

3. The ultrasonic jade polishing machine and its amplitude adaptive control method according to claim 1, characterized in that, In step S103, the upper limit of system amplitude A(f) is nonlinearly interpolated between the first amplitude value A1 and the second amplitude value A2 based on the magnitude of the frequency difference. The nonlinear interpolation is a quadratic interpolation or an S-curve interpolation.

4. The ultrasonic jade polishing machine and its amplitude adaptive control method according to claim 1, characterized in that, In step S104, the maximum change rates Rup and Rdown are set for the rise rate and fall rate of the actual output amplitude Aout, respectively, and the limit Rdown of the fall rate is greater than or equal to the limit Rup of the rise rate.

5. The ultrasonic jade polishing machine and its amplitude adaptive control method according to claim 1, characterized in that, In S102, the first frequency band B1 and the second frequency band B2 are symmetrical bandwidths, B1=[fc-Δ1, fc+Δ1], B2=[fc-Δ2, fc+Δ2], where Δ2>Δ1>0.

6. The ultrasonic jade polishing machine and its amplitude adaptive control method according to claim 1, characterized in that, In S102, the first frequency band B1 and the second frequency band B2 are asymmetric bandwidths, B1=[fc-Δ1-,fc+Δ1+], B2=[fc-Δ2-,fc+Δ2+], where Δ2->Δ1->0, Δ2+>Δ1+>0.

7. The ultrasonic jade polishing machine and its amplitude adaptive control method according to claim 1, characterized in that, In S105, the adaptive update of the maximum stress frequency center fc of the lock head includes: mapping estimation based on the oilstone length-frequency calibration curve, or frequency band corresponding to the peak temperature rise slope detected by frequency sweep test.

8. The ultrasonic jade polishing machine and its amplitude adaptive control method according to claim 1, characterized in that, In step S106, the specific triggering condition for the determination system to approach the lock's heating frequency band is as follows: The short-time frequency change rate exceeds the sum of the mean and K times the standard deviation of the normal drift rate baseline within at least Tmin consecutive sliding windows.

9. The ultrasonic jade polishing machine and its amplitude adaptive control method according to claim 1, characterized in that, In S106, the recorded restricted frequency band has a time decay mechanism or a number decay mechanism. As time goes by or the number of normal passes increases, its weight or influence range automatically decays. When the decay is lower than a preset threshold, it is automatically released.

10. An ultrasonic jade polishing machine and its amplitude adaptive control method according to claim 1, characterized in that, In S107, the redundancy protection control includes: An additional derating is applied when the detected temperature exceeds the first threshold T1; The system shuts down when the temperature exceeds a higher second threshold T2, and limits the output when a sudden change in active power is detected to prevent power runaway.

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