Control method and device of electric trephine and electric trephine device

Abstract

The invention discloses a control method and device of an electric trephine and an electric trephine device.The control method comprises the steps that collected current signals of motor operation are stored in a sliding window with the length being M, and the current signals are cached; preprocessing the current signal cached in the sliding window to remove low-frequency interference and high-frequency interference; based on the preprocessed current signals, abrupt change effect characteristics used for representing sawtooth penetration are extracted; comparing the abrupt change effect characteristic with a preset threshold value, and determining whether the saw teeth are penetrated or not; when it is determined that the sawteeth penetrate, the current signal for motor operation is stopped from being output, and the motor stops operating; and when it is determined that the sawteeth are not penetrated, continuing to execute the previous steps. According to the control method of the electric trephine, the current signal in the trephine penetrating process is monitored in real time, whether the sawteeth penetrate the bone or not is accurately judged, and therefore the safety and accuracy of the operation process are effectively improved.

Description

Technical Field

[0001] The present invention relates to the field of medical technology, and in particular to a control method and device for an electric ring saw and an electric ring saw device. Background Art

[0002] Electric ring saws are used to make holes in bone tissue. Compared with traditional sawtooth drilling methods, electric ring saws can make large holes at one time. Moreover, the bone at the resected site is removed after ring cutting of the hole, and then the bone at the resected site is put back to the hole after the operation. This can reduce surgical trauma and help patients recover quickly.

[0003] The existing electric trephine can only realize the drilling function, but cannot realize closed-loop control. There is no safety reminder and protection for whether the hole is penetrated or whether the soft tissue on the opposite side will be damaged. In most cases, it can only be judged by the doctor's experience, which is not very safe. Summary of the invention

[0004] Based on this, it is necessary to provide a control method and device for an electric ring saw and an electric ring saw device to improve safety in order to address the problem that existing electric ring saws cannot stop after penetration and have poor safety.

[0005] A control method for an electric ring saw, used for controlling the operation or stopping of the electric ring saw, wherein the front end of the electric ring saw is provided with a plurality of saw teeth arranged at intervals along a circumferential direction, and the control method comprises:

[0006] S1: storing the collected current signal of the motor in a sliding window of length M to cache the current signal;

[0007] S2: preprocessing the current signal buffered in the sliding window to remove low-frequency interference and high-frequency interference;

[0008] S3: extracting a mutation effect feature for characterizing the sawtooth penetration based on the preprocessed current signal;

[0009] S4: comparing the mutation effect feature with a preset threshold to determine whether the sawtooth has penetrated; and,

[0010] S5: When it is determined that the sawtooth penetrates, the output of the current signal for the motor to run is stopped, and the motor stops running; when it is determined that the sawtooth does not penetrate, S1-S4 are continued.

[0011] In one embodiment, the process of extracting the mutation effect feature for characterizing the sawtooth penetration based on the preprocessed current signal includes:

[0012] Perform an M - point Fourier transform on the pre - processed current signal to convert the time - domain signal into a frequency - domain signal, and extract the modulus value X(f0) of the fundamental frequency f0 of the signal and the modulus values X(f1), X(f2),..., X(fn) of the multiple - frequency frequencies f1, f2,..., fn of the fundamental frequency f0.

[0013] In one embodiment, 1. The process of comparing the mutation effect feature with a preset threshold to determine whether the saw - tooth has penetrated includes:

[0014] Compare the modulus value X(f0) of the fundamental frequency f0, and the modulus values X(f1), X(f2),..., X(fn) of the multiple - frequency frequencies with the preset thresholds thread0, thread1, thread2,..., threadn respectively;

[0015] If X(f0) < thread0, and X(f1)>thread1, or X(f2)>thread2, or X(fn)>threadn, then determine that the saw - tooth has penetrated.

[0016] In one embodiment, the process of extracting the mutation effect feature for characterizing the penetration of the saw - tooth based on the pre - processed current signal includes:

[0017] Extract the maximum value max1 of the pre - processed current signal, perform data differentiation on the pre - processed current signal, calculate the current change rate, and extract the maximum current change rate max2.

[0018] In one embodiment, the process of comparing the mutation effect feature with a preset threshold to determine whether the saw - tooth has penetrated includes:

[0019] Compare the maximum value max1 of the current signal and the maximum current change rate max2 with I_thread and I_diff_thread respectively;

[0020] If max1>I_thread and max2>I_diff_thread, then determine that the saw - tooth has penetrated.

[0021] In one embodiment, the motor is an AC motor, and the method further includes:

[0022] Collect the original current signal of the motor operation;

[0023] Convert the collected original current signal into a digital signal through a high - speed ADC chip.

[0024] In one embodiment, the motor is an AC brushless motor, and the original current signal collected in the step of collecting the original current signal of the motor is a current signal of any phase of the AC brushless motor.

[0025] In one embodiment, the preprocessing of the current signal cached in the sliding window to remove low-frequency interference and high-frequency interference includes:

[0026] The DC component in the current signal is filtered out through the FIR high-pass filter to remove low-frequency interference;

[0027] The high-frequency noise in the current signal is filtered out by a FIR low-pass filter to remove high-frequency interference.

[0028] A control device for an electric ring saw, used for controlling the operation or stopping of the electric ring saw, wherein the front end of the electric ring saw is provided with a plurality of saw teeth arranged at intervals along the circumferential direction, and the control device comprises:

[0029] A data cache module is used to store the collected current signal of the motor operation in a sliding window of length M for cache processing;

[0030] A signal preprocessing module, used for preprocessing the current signal cached in the sliding window by the data cache module to remove low-frequency interference and high-frequency interference;

[0031] A feature extraction module, used for extracting a mutation effect feature characterizing the sawtooth penetration based on the current signal preprocessed by the signal preprocessing module;

[0032] A comparison module, used to compare the mutation effect feature extracted by the feature extraction module with a preset threshold; and

[0033] A control signal output module is used to determine whether the sawtooth has penetrated according to the comparison result of the comparison module, and output the current signal of the motor operation or stop outputting the current signal of the motor operation; wherein,

[0034] When it is determined that the sawtooth penetrates, the output of the current signal of the motor operation is stopped and the motor stops running; when it is determined that the sawtooth does not penetrate, the caching, preprocessing and feature extraction of the current signal are continued until it is determined that the sawtooth penetrates.

[0035] An electric ring saw device comprises an electric ring saw and a driving handle, wherein the front end of the electric ring saw is provided with a plurality of saw teeth spaced apart in a circumferential direction, the driving handle comprises a motor, a motor driver and a controller, the motor driver is connected to the motor and the controller, the controller comprises a computer program, and the steps of the method are implemented when the computer program is executed by a processor.

[0036] The control method, device and electric ring saw device of the electric ring saw can accurately determine whether the saw teeth have penetrated the bone by real-time monitoring of the current signal during the penetration process of the ring saw, thereby effectively improving the safety and accuracy of the surgical process. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 is a cross-sectional view of an electric ring saw device in one embodiment of the present invention;

[0038] Figure 2 for Figure 1 A local enlarged schematic diagram of the middle A;

[0039] Figure 3 for Figure 1 A block diagram of a drive handle of an electric ring saw device as shown in;

[0040] Figure 4 The present invention is a flowchart of a control method of an electric ring saw in one embodiment of the present invention.

[0041] Description of reference numerals:

[0042] 100. Electric ring saw;

[0043] 110. Ring saw housing;

[0044] 120, outer ring saw unit; 121, outer saw teeth;

[0045] 130, inner ring saw unit; 131, inner saw teeth;

[0046] 140. Transmission parts;

[0047] 200, driving handle; 210, handle shell; 220, motor; 230, motor driver; 240, ADC module; 250, controller; 251, data cache module; 252, signal preprocessing module; 253, feature extraction module; 254, comparison and judgment module; 255, control signal output module. DETAILED DESCRIPTION

[0048] In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and understandable, the specific implementation methods of the present invention are described clearly and completely below in conjunction with the accompanying drawings. Obviously, the specific details described below are only part of the embodiments of the present invention, and the present invention can also be implemented in many other embodiments different from those described herein. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work belong to the protection scope of the present invention.

[0049] In this document, when an element is referred to as being "fixed to" another element, it may be directly on the other element or there may be an intermediate element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be an intermediate element at the same time. The directional words such as front, back, top, and bottom involved are defined by the positions of the parts in the drawings and the positions of the parts relative to each other, just for the clarity and convenience of expressing the technical solution. It should be understood that the use of the directional words should not limit the scope of protection claimed in the present invention.

[0050] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0051] like Figure 1 , 2 As shown, the electric ring saw device in one embodiment of the present invention includes an electric ring saw 100 and a driving handle 200. The front end of the electric ring saw 100 is provided with a plurality of saw teeth arranged at intervals along the circumferential direction, which are used to open holes in human bone tissue (such as the spine); the driving handle 200 is used to drive the electric ring saw 100 to work.

[0052] The electric ring saw 100 includes a ring saw housing 110, a ring saw body, and a transmission member 140. The rear end of the ring saw body is rotatably mounted in the front end of the ring saw housing 110. The front end of the ring saw body is provided with saw teeth. The transmission member 140 is rotatably mounted in the rear end of the ring saw housing 110. The rear end of the transmission member 140 is provided with a connection interface. The front end of the transmission member 140 is in transmission cooperation with the rear end of the ring saw body. As an example, the ring saw body includes an inner ring saw unit 130 and an outer ring saw unit 120. The rear end of the outer ring saw unit 120 is rotatably mounted in the front end of the ring saw housing 110. The front end is provided with a plurality of outer saw teeth 121 arranged in a circumferential direction. The inner ring saw unit 130 is located inside the outer ring saw unit 120 and can rotate and move axially relative to the outer ring saw unit 120. The front end of the inner ring saw unit 130 extends out of the outer ring saw unit 120 and is provided with a plurality of inner saw teeth 131 arranged in a circumferential direction. The inner serrations 131 and the outer serrations 121 are used to circumscribe bone tissue to penetrate it.

[0053] like Figure 1 , 3As shown, the driving handle 200 includes a handle housing 210 and a motor 220, a motor driver 230 and a control device 250 arranged in the handle housing 210, wherein the output end of the motor 220 is connected to the transmission member 140, the motor driver 230 is connected to the motor 220, and is used to control the operation (i.e., running or stopping) of the motor 220, and the control device 250 is used to process the current signal of the motor operation, determine whether the saw teeth penetrate the bone, and when penetrating the bone, stop sending the current signal to the motor driver 230 to stop the motor 220.

[0054] like Figure 3 As shown, the control device 250 in the embodiment of the present application includes a data cache module 251, a signal preprocessing module 252, a feature extraction module 253, a comparison and judgment module 254 and a control signal output module 255. The data cache module 251 is used to store the collected current signal of the motor operation in a sliding window with a length of M for cache processing; the signal preprocessing module 252 is used to preprocess the current signal cached in the sliding window by the data cache module 251 to remove low-frequency interference and high-frequency interference; the feature extraction module 253 is used to characterize the signal based on the signal preprocessed by the signal preprocessing module 252. The characteristics of the bone penetration mutation effect are extracted; the comparison module 254 is used to compare the mutation effect characteristics extracted by the feature extraction module 253 with a preset threshold; the control signal output module 255 is used to determine whether the sawtooth has penetrated according to the comparison result of the comparison module 254, and output the current signal of the motor operation or stop outputting the current signal of the motor operation; wherein, when it is determined that the sawtooth has penetrated, the output of the current signal of the motor operation is stopped, and the motor stops running; when it is determined that the sawtooth has not penetrated, the current signal caching, preprocessing and feature extraction are continued until the sawtooth is determined to have penetrated.

[0055] In one embodiment, the motor 220 is an AC motor, and the driving handle 200 further includes an ADC (Analog-to-Digital Converter) module 240, which is used to convert analog signals into digital signals. Further, the motor 220 is an AC brushless motor. The ADC module 240 collects the current signal of any phase of the AC brushless motor.

[0056] Figure 4 A flow chart of a control method of an electric ring saw 100 provided in an embodiment of the present invention is shown. The control method of the electric ring saw 100 is used to control the operation or stop of the electric ring saw. The control method includes:

[0057] S1: Store the collected current signal of the motor in a sliding window of length M to cache the current signal. Sliding window is a data processing technology used to extract fixed-length data segments from continuous data for processing. The window size is fixed, and the data is updated each time the window is moved. The data cache is used to temporarily store data for subsequent processing. The function of the data cache is to store the collected current signal data in a sliding window of fixed length for real-time caching. The effect is to ensure the continuity and consistency of data processing and provide the latest valid data for subsequent processing.

[0058] S2: preprocessing the current signal buffered in the sliding window to remove low-frequency interference and high-frequency interference;

[0059] S3: extracting a mutation effect feature for characterizing the sawtooth penetration based on the preprocessed current signal;

[0060] S4: comparing the mutation effect feature with a preset threshold to determine whether the sawtooth has penetrated; and,

[0061] When it is determined that the sawtooth penetrates, the output of the current signal for the motor to run is stopped, and the motor stops running; when it is determined that the sawtooth does not penetrate, S1-S4 is continued to be executed.

[0062] During the process of drilling bone with the electric ring saw 100, its current signal has different characteristics at different stages. During the steady bone drilling process, the current signal is relatively stable. During the penetration process, its current signal will produce obvious mutation effects, and then produce obvious differences in time domain and frequency domain from the current signal during the steady bone drilling process. The control method of the embodiment of the present invention utilizes these differences to realize bone tissue penetration recognition and emergency stop control, thereby effectively improving the safety and accuracy of the surgical process.

[0063] In one embodiment, the collected current signal of the motor operation is stored in a sliding window of length M to cache the current signal. Specifically, the length of M is an exponent of 2, which can be 1024 bytes, 2048 bytes, etc.

[0064] In one embodiment, the steps of preprocessing the current signal cached in the sliding window to remove low-frequency interference and high-frequency interference are as follows:

[0065] (1) High-pass filtering: The DC component (low-frequency component) in the current signal is filtered out through a FIR (Finite Impulse Response filter) high-pass filter to remove low-frequency interference.

[0066] (2) Low-pass filtering: Use FIR low-pass filter to filter out high-frequency noise in the current signal and remove high-frequency interference.

[0067] By preprocessing the original current signal, the signal-to-noise ratio is improved, ensuring the accuracy of subsequent processing.

[0068] During the steady bone drilling process, the current signal is relatively stable. At the moment of penetration, due to the loss of resistance, the current signal will suddenly change, and the rate of change will increase sharply. Therefore, it can be judged whether it is penetrated by comparing the size and rate of change of the current signal. In addition, it is found through experiments that during the steady bone drilling process, only one outer sawtooth 121 and one inner sawtooth 131 among the plurality of outer sawtooths 121 and the plurality of inner sawtooths 131 are in contact with the bone tissue, that is, in a complete rotation cycle, only one sawtooth will contact the tissue. At this time, the harmonic frequency generated by the contact between the sawtooth and the tissue is the same as the basic frequency (the frequency of the main engine speed); during the penetration process, 2, 3 or more sawtooths will contact the tissue, and each sawtooth will generate a pulse when it contacts the tissue once. At this time, when multiple sawtooths contact the tissue, each sawtooth will cause a change in the current signal each time it contacts, resulting in the current signal containing not only the basic frequency of the main engine speed, but also the harmonic frequencies of its multiples. These harmonic frequencies are integer multiples of the basic frequency. By analyzing these frequency components and their energy changes, it can be judged whether the sawtooth has penetrated the tissue.

[0069] In one embodiment, based on the preprocessed current signal, the specific steps of extracting the mutation effect feature for characterizing the sawtooth penetration are as follows:

[0070] (1) Extracting the maximum value: Extract the maximum value max1 of the preprocessed signal.

[0071] (2) Data differentiation: Differentiate the preprocessed current signal, calculate the current change rate, and extract the maximum current change rate max2. Data differentiation is a method for calculating the signal change rate. By differentiating the signal, the signal change rate is obtained. The function of data differentiation is to calculate the change rate of the current signal and detect the sudden change of the current signal. The maximum current change rate max2 is the maximum value of the current change rate within a certain time window, reflecting the sudden change characteristics of the current signal during the penetration process.

[0072] (3) Fourier transform: Perform an M-point Fourier transform on the preprocessed signal to convert the time domain signal into a frequency domain signal, and extract the modulus value X(f0) of the signal's fundamental frequency f0 and the modulus values ​​X(f1), X(f2), ..., X(fn) of the multiple frequencies f1, f2, ..., fn of the fundamental frequency f0.

[0073] The fundamental frequency f0 is the main frequency component in the signal, that is, the rotational speed frequency of the motor 220, which can be calculated from the rotational speed of the motor 220. The multiple frequencies f1, f2,..., fn are the integer multiple frequency components of the fundamental frequency. The modulus value is the amplitude of the frequency component, representing the intensity of the frequency component.

[0074] Among the maximum value max1, the maximum current change rate max2, the modulus value X(f0) of the fundamental frequency f0, and the modulus values of the multiple frequencies f1, f2,..., fn of the fundamental frequency f0, a single condition can be used alone as the basis for judging whether the sawtooth penetrates, or any two conditions can be combined as the basis for judging whether the sawtooth penetrates, or three conditions can be combined as the basis for judging whether the sawtooth penetrates.

[0075] In one embodiment, comparing the mutation effect feature with a preset threshold to determine whether the sawtooth has penetrated specifically includes the following steps:

[0076] (1) Comparison of the maximum value current: Compare the maximum value max1 with the peak threshold value I_thread obtained from the look-up table. If max1 > I_thread, it means that the bone has been penetrated.

[0077] (2) Comparison of the maximum current change rate: Compare the maximum current change rate max2 with the current differential threshold value I_diff_thread obtained from the look-up table. If max2 > I_diff_thread, it means that the bone has been penetrated. I_diff_thread is an empirical value.

[0078] (3) Comparison of frequency components: Compare X(f0), X(f1), X(f2),..., X(fn) with thread0, thread1, thread2,..., threadn respectively; if X(f0) < thread0 and X(f1) > thread1, or X(f0) < thread0, X(f2) > thread2,..., or X(f0) < thread0, X(fn) > threadn, it means that the bone has been penetrated. thread0, thread1, thread2,..., threadn are empirical values.

[0079] I_thread, I_diff_thread, thread0, thread1, thread2,..., threadn are empirical values, and these thresholds are obtained by analyzing and statistically processing a large amount of experimental data. The specific implementation method is as follows:

[0080] 1. Data acquisition:

[0081] A large amount of motor current signal data is collected in the actual operating environment, including the current signal of the ring saw during normal drilling, the current signal of the ring saw at the moment of penetrating the bone and after, and the current signal of the ring saw at different gears and different drilling speeds.

[0082] 2. Data preprocessing:

[0083] (1) Preprocess the collected current signal, including filtering out the DC component and high-frequency noise, and extracting the effective signal.

[0084] (2) Differentiate the current signal and calculate the current change rate.

[0085] (3) Perform Fourier transform on the current signal and extract the frequency component.

[0086] 3. Feature extraction:

[0087] (1) Maximum current: The maximum current value I_max under different states.

[0088] (2) Maximum current change rate: The maximum current change rate I_diff_max obtained by differentiation.

[0089] (3) Frequency component energy: The energy of the main engine speed frequency f3 and its multiple frequency f4 after Fourier transform.

[0090] 4. Threshold setting:

[0091] (1) Setting of I_thread: During normal drilling, record the peak value of the current signal I_max'. At the moment of penetrating the bone, the current signal will have a significant mutation. Statistically analyze these data and set the threshold value of the current peak value I_thread. The maximum value of the current peak value during normal drilling plus a safety margin can be taken, and I_thread is 1.3-1.6 times I_max'.

[0092] (2) Setting of I_diff_thread: Record the maximum value of the current change rate I_diff_max' under different states. At the moment of penetration, the current change rate will increase sharply. Statistically analyze these data and set the threshold value of the current change rate I_diff_thread. The maximum value of the current change rate under normal conditions plus a safety margin can be taken. I_diff_thread can be 1.3-1.6 times I_diff_max'.

[0093] (4) Setting of thread0, thread1, thread2, ..., threadn: Extract the modulus values ​​X(f0)', X(f1)', X(f2)', ..., X(fn)' of the frequency components f0, f1, f2, ..., fn through Fourier transform. Statistically analyze the energy changes of the frequency components during and after normal drilling and penetration. Thread0 can be set to the minimum energy value of the main engine speed frequency f0 under normal conditions minus a safety margin, and Thread0 can be 0.3-0.6 times X(f0)'. thread1, thread2, ..., threadn can be set to the maximum value of the modulus X(f0)', X(f1)', X(f2)', ..., X(fn)' of the multiplied frequencies f0, f1, f2, ..., fn in the normal state plus a safety margin. thread1 can be 1.3-1.6 times X(f1)', thread2 can be 1.3-1.6 times X(f2)', ..., threadn can be 1.3-1.6 times X(fn)'.

[0094] 6. Experimental verification:

[0095] Verify whether the set threshold is reasonable in actual operation to ensure accurate judgment when penetrating the bone.

[0096] According to the verification results, adjust the threshold to achieve the best effect.

[0097] Through the above steps and methods, the thresholds of I_thread, I_diff_thread, thread1, thread2, ..., threadn can be reasonably set to ensure accurate judgment when the trephine penetrates the bone.

[0098] S5. When it is determined that the sawtooth penetrates, the output of the current signal for the motor to run is stopped, and the motor stops running; when it is determined that the sawtooth does not penetrate, S1-S4 are continued.

[0099] When the judgment condition is met, a stop signal is output to stop the motor to ensure safety. If the judgment condition is not met, data collection and processing will continue until the judgment condition is met. That is, the window slides according to the set step size, the data M point cache is updated, the newly sampled data points enter the cache, and the old data points are removed.

[0100] By using the method of the present invention, the current signal during the penetration process of the ring saw can be monitored in real time, and it can be accurately determined whether the saw teeth have penetrated the bone, thereby effectively improving the safety and accuracy of the surgical process.

[0101] In one embodiment, the motor is an AC motor, and the control method of the electric ring saw further includes:

[0102] S01: Collecting the original current signal of the motor operation. When the electric ring saw is working, the original current signal of the motor is collected in real time. In another embodiment, the motor is an AC brushless motor, and the collected original current signal is the current signal of any phase of the AC brushless motor. Since the brushless motor has no contact between the brush and the commutator, no brush sparks will be generated during operation, and therefore no electromagnetic interference will be generated. Therefore, no interference current will be generated when the motor is running, thereby avoiding the problem of misjudgment caused by the interference current and improving the accuracy of the control method.

[0103] S02: Convert the collected raw current signal into a digital signal through a high-speed ADC chip. The high-speed ADC chip has the characteristics of high sampling rate and high precision, and can accurately convert analog signals into digital signals in a short time, thereby providing basic data for subsequent signal processing and motor control.

[0104] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. A control method for an electric ring saw, used for controlling the operation or stopping of the electric ring saw, wherein the front end of the electric ring saw is provided with a plurality of saw teeth arranged at intervals along the circumferential direction, characterized in that: The control method includes: S1: Store the collected current signal of the motor operation in a sliding window with a length of M to perform caching processing on the current signal; S2: Preprocess the current signal cached in the sliding window to remove low-frequency interference and high-frequency interference; S3: Based on the preprocessed current signal, extract the mutation effect characteristics used to characterize the sawtooth penetration; S4: Compare the mutation effect characteristics with a preset threshold to determine whether the sawtooth has penetrated; and, S5: When it is determined that the sawtooth has penetrated, stop outputting the current signal of the motor operation, and the motor stops running; when it is determined that the sawtooth has not penetrated, continue to execute S1-S4.

2. The control method of the electric ring saw according to claim 1, characterized in that: The process of extracting the mutation effect characteristics used to characterize the sawtooth penetration based on the preprocessed current signal includes: Perform M-point Fourier transform on the preprocessed current signal to convert the time-domain signal into a frequency-domain signal, and extract the modulus value X(f0) of the fundamental frequency f0 of the signal and the modulus values X(f1), X(f2),..., X(fn) of the multiple frequencies f1, f2,..., fn of the fundamental frequency f0.

3. The control method of the electric ring saw according to claim 2, characterized in that: The process of comparing the mutation effect characteristics with a preset threshold to determine whether the sawtooth has penetrated includes: Compare the modulus value X(f0) of the fundamental frequency f0, the modulus values X(f1), X(f2),..., X(fn) of the multiple frequencies with the preset thresholds thread0, thread1, thread2,..., threadn respectively; If X(f0) < thread0 and X(f1) > thread1, or X(f2) > thread2, or X(fn) > threadn, it is determined that the sawtooth has penetrated.

4. The control method of the electric ring saw according to claim 1, characterized in that: The process of extracting the mutation effect characteristics used to characterize the sawtooth penetration based on the preprocessed current signal includes: Extract the maximum value max1 of the preprocessed current signal, perform data differentiation on the preprocessed current signal, calculate the current change rate, and extract the maximum current change rate max2.

5. The control method of the electric ring saw according to claim 4, characterized in that: The process of comparing the mutation effect characteristics with a preset threshold to determine whether the sawtooth has penetrated includes: Compare the maximum value max1 of the current signal and the maximum current change rate max2 with I_thread and I_diff_thread respectively; If max1 > I_thread and max2 > I_diff_thread, it is determined that the sawtooth has penetrated.

6. The control method of the electric ring saw according to claim 1, characterized in that: The motor is an AC motor, and the method further includes: Collect the original current signal of the motor operation; Convert the collected original current signal into a digital signal through a high-speed ADC chip.

7. The control method of the electric ring saw according to claim 6, characterized in that: The motor is a brushless AC motor, and the collected original current signal is the current signal of any phase of the brushless AC motor.

8. The control method of the electric ring saw according to claim 1, characterized in that: The preprocessing of the current signal cached in the sliding window to remove low-frequency interference and high-frequency interference includes: Filter out the DC component in the current signal through a FIR high-pass filter to remove low-frequency interference; The high-frequency noise in the current signal is filtered out by a FIR low-pass filter to remove high-frequency interference.

9. A control device for an electric ring saw, used for controlling the operation or stopping of the electric ring saw, wherein the front end of the electric ring saw is provided with a plurality of saw teeth arranged at intervals along the circumferential direction, characterized in that: The control device comprises: A data cache module is used to store the collected current signal of the motor operation in a sliding window of length M for cache processing; A signal preprocessing module, used for preprocessing the current signal cached in the sliding window by the data cache module to remove low-frequency interference and high-frequency interference; A feature extraction module, used for extracting a mutation effect feature characterizing the sawtooth penetration based on the current signal preprocessed by the signal preprocessing module; A comparison module, used to compare the mutation effect feature extracted by the feature extraction module with a preset threshold; and A control signal output module is used to determine whether the sawtooth has penetrated according to the comparison result of the comparison module, and output the current signal of the motor operation or stop outputting the current signal of the motor operation; wherein, When it is determined that the sawtooth penetrates, the output of the current signal of the motor operation is stopped and the motor stops running; when it is determined that the sawtooth does not penetrate, the caching, preprocessing and feature extraction of the current signal are continued until it is determined that the sawtooth penetrates.

10. An electric ring saw device, characterized in that: It comprises an electric ring saw and a driving handle, wherein the front end of the electric ring saw is provided with a plurality of saw teeth spaced apart in a circumferential direction, the driving handle comprises a motor, a motor driver and the control device of the electric ring saw as claimed in claim 9, and the motor driver is connected to the motor and the control device of the electric ring saw.

Images