CN115570447A - A monitoring method, system, terminal and medium for anti-collision of CNC machine tools - Google Patents

Abstract

The application relates to the field of numerical control machines, in particular to a monitoring method for preventing collision of a numerical control machine, which comprises the following steps: acquiring an obstacle outline and a relative distance between a cutter and the obstacle outline based on a plurality of piezoelectric crystals preset at the cutter; and controlling the machine tool to stop acting in response to the relative distance being smaller than a preset safe distance. The method and the device can reduce the probability of cutter collision accidents, reduce the phenomenon of cutter damage caused by the collision of obstacles, and reduce the problem of the mechanical structure of the numerical control machine caused by the occurrence of serious cutter collision events.

Description

A monitoring method, system, terminal and medium for anti-collision of CNC machine tools

technical field

The invention relates to the field of numerically controlled machine tools, in particular to a monitoring method, system, terminal and medium for anti-collision of numerically controlled machine tools.

Background technique

Five-axis linkage CNC machine tool is a kind of machine tool specially used for processing complex curved surfaces. In five-axis linkage CNC machine tool, the machining of pentahedron can be completed by one clamping of the workpiece. Since the five-axis linkage CNC machine tool can process complex spatial surfaces with high precision, it is often used to process molds such as auto parts and aircraft structural parts.

In the process of processing, knife collision is a common accident with very serious consequences. The main reasons for knife collision accidents are:

1. When using the hand wheel for tool setting operation, because the operator is not skilled in the forward and reverse operation of the hand wheel, the tool often collides with the workpiece.

2. During tool setting, when the tool is controlled to touch the workpiece by operating the hand wheel, the improper selection of the rotation speed of the hand wheel will cause the tool to contact the workpiece at a relatively high feed rate, thereby causing the tool to collide with the workpiece.

3. The cutting height of the cutting tool is insufficiently reserved, so that the cutting tool collides with the fixture or the boss of the workpiece.

4. The establishment of the craftsman's coordinate system is wrong, resulting in a mismatch between the used coordinate system and the machining coordinate system. When the program is running, the tool and the workpiece will collide.

5. Improper manual programming, incorrect input of coordinate data or shape programming data, resulting in tool collision.

6. After the program is interrupted, the instruction to re-call the auxiliary function is neglected, causing the program to collide abnormally.

7. There is a problem with manual temporary tool change, such as changing a smaller tool to a larger tool or changing a short tool to a long tool.

Once the tool collision occurs, it will cause damage to the tool, resulting in a decrease in the machining accuracy of the machine tool, and the workpiece will also be damaged, greatly reducing the processing efficiency. What's more serious is that due to the material problems of each module of the CNC machine tool, the knife collision will even cause problems in the mechanical structure of the entire CNC machine tool, making it impossible to continue the processing work.

In the existing technology, by perfecting the operation process and program writing of CNC machine tools to avoid tool collision accidents during processing, the existing technology generally relies on program testing, simulation verification, etc. to check whether there is a tool collision, and the operation depends on the operator's own standardization Avoid knife collision, but in actual production and processing accidents occur from time to time, the prior art can not reduce the probability of knife collision accidents well.

Contents of the invention

In order to reduce the probability of tool collision accidents, the present application provides a monitoring method, system, terminal and medium for anti-collision of CNC machine tools.

A monitoring method for anti-collision of a CNC machine tool provided by the application adopts the following technical scheme:

A monitoring method for anti-collision of a CNC machine tool, comprising the following steps:

Obtaining the obstacle contour and the relative distance between the cutter and the obstacle contour based on a plurality of piezoelectric crystals preset at the tool; in response to the relative distance being less than a preset safety distance, controlling the machine tool to stop.

By adopting the above-mentioned technical scheme, by setting the piezoelectric crystal at the cutter, the obstacle contour and the relative distance between the cutter and the obstacle contour are obtained, and the relative distance is compared with the preset safety distance, and when the relative distance is smaller than the safety distance , to control the machine tool to stop, so as to reduce the occurrence of knife collision accidents.

By installing a detection device on the machine tool, during the machining operation of the CNC machine tool, the surrounding environment of the tool can be monitored in real time, the phenomenon of tool damage caused by obstacles colliding with the tool can be reduced, and the mechanical structure problems of the CNC machine tool caused by serious tool collision events can be reduced. The phenomenon.

Preferably, the step of obtaining the obstacle contour and the relative distance between the cutter and the obstacle contour based on several piezoelectric crystals preset at the cutter includes: applying an alternating voltage to the piezoelectric crystal , so that the piezoelectric crystal emits ultrasonic waves; obtain ultrasonic reflected waves based on the piezoelectric crystals, perform data processing on the ultrasonic reflected waves to obtain radio frequency signals; perform signal processing on the radio frequency signals to obtain baseband signals; A B-mode ultrasonic image is obtained from the baseband signal; based on the B-mode ultrasonic image, the position of the obstacle and the contour of the obstacle are calculated.

By adopting the above technical scheme, after the CNC machine tool starts normally, an alternating voltage is applied to the piezoelectric crystal, and the piezoelectric crystal alternately changes in elongation and compression according to its thickness direction, and vibration is generated through deformation, and the piezoelectric crystal vibrates when it deforms The frequency is the same as the frequency of the alternating voltage, if the frequency of the alternating voltage is set as the ultrasonic frequency, the medium around the piezoelectric crystal will also generate ultrasonic waves of the same frequency. Due to the high frequency and short wavelength of ultrasonic waves, the conditions for diffraction to occur are more difficult than those of ordinary sound waves, which usually propagate in a straight line. Therefore, a single piezoelectric crystal monitors obstacles in the same vertical direction as it, and responds to the received ultrasonic reflected waves. After the above processing and calculation, the purpose of calculating the obstacle position and obstacle contour is achieved. Moreover, as a high-frequency sound wave, ultrasonic waves have good stability, are less affected by the environment, and are not affected by factors such as poor light inside the CNC machine tool, making monitoring more accurate.

Preferably, the step acquires ultrasonic reflected waves based on the ultrasonic waves, performs data processing on the ultrasonic reflected waves, and obtains radio frequency signals, including: performing time gain compensation on the ultrasonic reflected waves; converting the ultrasonic reflected waves It is a digital signal; digital wave synthesis is performed on the digital signal to form scan line data and the scan line data is used as the radio frequency signal.

By adopting the above technical solution, due to the scattering and other losses of the ultrasonic wave on the transmitting and receiving paths, the received ultrasonic reflected wave increases with the receiving time, and its relative intensity is small. Therefore, the use of time gain compensation for the received ultrasonic reflection can weaken the subsequent processing problems caused by the decrease of signal strength with depth. In order to improve the signal processing efficiency and reduce the complexity of the upper computer, it is necessary to use analog-to-digital conversion to convert the ultrasonic reflected wave into a digital signal. The channel data after the analog-to-digital conversion is completed, according to the delay difference caused by the difference in the distance between the monitoring point and the receiving point of the ultrasonic reflected wave, digital beamforming scan line data is performed. Specifically, due to the different paths of the ultrasonic wave, the reflected back wave The wave time is different. Digital wave synthesis refers to obtaining the original information matrix of the target point, coherently superimposing the target echo signal corresponding to the target pixel point, and obtaining the synthesized echo signal corresponding to the target pixel point. The data obtained after completion Known as radio frequency signal data.

Preferably, the first time node is recorded, and the first time node is the time node when an alternating voltage is applied to the piezoelectric crystal; the second time node is recorded, and the second time node is the time when ultrasonic reflected waves are received; Calculate the difference between the first time node and the second time node as a time difference; calculate the relative distance, the obstacle position and the obstacle contour according to the time difference and the ultrasonic transmission speed.

By adopting the above technical solution, the propagation speed of ultrasonic wave is 340m/s, the relative distance between the obstacle and the piezoelectric crystal is equal to the propagation speed of ultrasonic wave multiplied by the above time difference, and the position of the obstacle is obtained by calculating the relative distance between the obstacle and the piezoelectric crystal , that is, when all piezoelectric crystals transmit and receive ultrasonic signals, the position and contour of the obstacle at the monitoring position can be obtained.

Preferably, in response to the relative distance being less than a preset safety distance, an alarm is performed and the dangerous area on the outline of the obstacle is displayed through a visual interface.

By adopting the above technical solution, the obstacle outline is displayed on a visual interface, and the position on the obstacle outline whose relative distance is less than the safety distance is marked as a dangerous area, which can be conveniently and intuitively displayed to the operator, and the obstacle outline at the monitoring position Hazardous area location for easy operator adjustments.

Preferably, an alarm-free timing operation is performed in response to obtaining the alarm-free instruction.

By adopting the above-mentioned technical scheme, in response to obtaining the alarm-free command, the alarm-free timing is performed, and within the alarm-free time range, when the relative distance between the obstacle and the piezoelectric crystal is less than the safe distance, the alarm signal will not be issued and the The machine tool moves, and at this time, it can be used by the operator to adjust the workpiece position and other operations.

Preferably, the step is in response to obtaining the alarm-free instruction, and executing the alarm-free timing operation includes: obtaining the alarm-free instruction; performing alarm-free timing based on the preset alarm-free time; within the alarm-free time, no alarm is issued Signal; when the alarm-free time is exceeded, and when the relative distance is less than the safety distance, an alarm signal is sent and the machine tool is controlled to stop.

By adopting the above technical scheme, the operator can stop the alarm after confirming the alarm-free on the interface that can perform human-computer interaction, and make the machine tool continue to work. At the same time, the alarm-free timing is performed. When the relative distance to the piezoelectric crystal is less than the safe distance, no alarm signal will be issued and the movement of the machine tool will not be prevented. At this time, the operator can adjust the workpiece position and other operations. Through the visual interface, the operation of the entire monitoring system is intuitive and clear.

In the second aspect, the present application discloses a monitoring system for anti-collision of CNC machine tools, which adopts the above-mentioned monitoring system for anti-collision of CNC machine tools, including: a detection module, used to detect obstacles based on a number of piezoelectric crystals preset at the tool The contour and the relative distance between the tool and the obstacle contour; a safety determination module, configured to control the machine tool to stop in response to the relative distance being less than a preset safety distance.

By adopting the above technical solution, the detection module obtains the obstacle contour and the relative distance between the tool and the obstacle contour to calculate the obstacle position and the obstacle contour; the safety judgment module is used to respond to the relative distance being less than the preset Safety distance, control the machine tool stop action, in order to achieve real-time monitoring of the surrounding environment of the tool during the machining operation of the CNC machine tool, reduce the phenomenon of tool damage caused by obstacles colliding with the tool, and reduce the damage caused by serious tool collision events. The situation where there is a problem with the mechanical structure of the CNC machine tool.

In the third aspect, the present application discloses a terminal device, including a memory, a processor, and a computer program stored in the memory and capable of running on the processor. When the processor loads and executes the computer program, the above-mentioned numerical control machine tool is used. Monitoring method for collision avoidance.

By adopting the above technical solution, the computer program is generated by the above-mentioned monitoring method for the anti-collision of CNC machine tools, and stored in the memory, to be loaded and executed by the processor, so that the terminal equipment is made according to the memory and the processor, which is convenient for users to use.

In a fourth aspect, the present application discloses a computer-readable storage medium, which adopts the following technical solution: a computer-readable storage medium, wherein a computer program is stored in the computer-readable storage medium, and the computer program is loaded by a processor And when it is executed, the above-mentioned monitoring method for anti-collision of the numerical control machine tool is adopted.

By adopting the above-mentioned technical solution, a computer program is generated by the above-mentioned monitoring method for anti-collision of a numerical control machine tool, and stored in a computer-readable storage medium, so as to be loaded and executed by a processor. read and store.

Description of drawings

Fig. 1 is a method flowchart of steps S1-S4 in a monitoring method for anti-collision of a numerically controlled machine tool in the present application.

Fig. 2 is a schematic cross-sectional structure diagram of a piezoelectric crystal shown in a monitoring method for anti-collision of a numerically controlled machine tool in the present application.

Fig. 3 is a method flowchart of steps S10-S14 in a monitoring method for anti-collision of a numerically controlled machine tool in the present application.

Fig. 4 is a method flowchart of steps S140-S143 in a monitoring method for anti-collision of a numerically controlled machine tool in the present application.

Fig. 5 is a method flowchart of steps S40-S41 in a monitoring method for anti-collision of a numerically controlled machine tool in the present application.

Reference signs:

1. Piezoelectric crystal; 2. Tool seat; 3. Spindle.

detailed description

The embodiment of the present application discloses a monitoring method for anti-collision of CNC machine tools. Referring to FIG. 1, the monitoring method for anti-collision of CNC machine tools includes:

S1: Obtain the relative distance between the obstacle contour and the cutter and the obstacle contour based on some piezoelectric crystals 1 preset at the cutter;

Referring to Figure 2, the tool seat 2 is arranged between the piezoelectric crystal 1 and the workpiece, the tool seat 2 is used to install the tool, and multiple piezoelectric crystals 1 are implanted in the main shaft 3 of the machine tool. axis of rotation.

Referring to Fig. 3, step S1 comprises the following steps,

S10: Apply an alternating voltage to the piezoelectric crystal 1, so that the piezoelectric crystal 1 emits ultrasonic waves;

Specifically, after the CNC machine tool starts up normally, it starts to execute normal processing instructions, and at the same time, an alternating voltage is applied to the piezoelectric crystal 1, and the piezoelectric crystal 1 undergoes alternate changes of elongation and compression according to its thickness direction, and vibration is generated through deformation. When the piezoelectric crystal 1 is deformed, the vibration frequency is the same as the frequency of the alternating voltage. If the frequency of the alternating voltage is set as the ultrasonic frequency, the medium around the piezoelectric crystal 1 will also generate ultrasonic waves of the same frequency.

Among them, due to the high frequency and short wavelength of ultrasonic waves, the conditions for diffraction to occur are more difficult than those of ordinary sound waves, which usually propagate in a straight line, so a single piezoelectric crystal 1 monitors obstacles in the same vertical direction as it.

At the same time, because the monitoring direction is the vertical direction, if the obstacle approaches the tool in the horizontal direction, the Doppler effect on the ultrasonic wave during the monitoring process is minimal. If the obstacle approaches the tool in the vertical direction, the wavelength of the reflected ultrasonic wave will be When the frequency of the alternating voltage fed back by the piezoelectric crystal 1 is abnormal, the preset monitoring system on the machine tool can respond faster.

When the ultrasonic waves are reflected back to the piezoelectric crystal 1, the piezoelectric crystal 1 generates a voltage, and the voltage intensity signal is uploaded to the preset host computer, and the host computer displays the voltage intensity signal as a light spot through a visual screen, and the intensity is represented by the brightness of the light spot , the greater the intensity, the stronger the photoelectric brightness, and the section image is composed according to the light spot and photoelectric intensity.

S11: Obtain ultrasonic reflected waves based on the piezoelectric crystal 1, perform data processing on the ultrasonic reflected waves, and obtain radio frequency signals;

S110: performing time gain compensation on the ultrasonic reflected wave;

Due to the scattering and other losses of ultrasonic waves in the transmission and reception paths, the received ultrasonic reflected waves increase with the receiving time, and their relative strength is small. Therefore, the use of time gain compensation for the received ultrasonic reflection can weaken the subsequent processing problems caused by the decrease of signal strength with depth.

S111: converting the ultrasonic reflected wave into a digital signal;

In order to improve the signal processing efficiency and reduce the complexity of the upper computer, it is necessary to use analog-to-digital conversion to convert the ultrasonic reflected wave into a digital signal.

S112: Perform digital wave synthesis on the digital signal to form scan line data and use the scan line data as a radio frequency signal.

Among them, through the channel data after the analog-to-digital conversion, according to the delay difference caused by the difference in the distance between the monitoring point and the receiving point of the ultrasonic reflected wave, the digital beamforming scan line data is carried out. Specifically, due to the different paths of the ultrasonic waves, so The time to receive reflected echoes is different. Digital wave synthesis refers to obtaining the original information matrix of the target point, coherently superimposing the target echo signal corresponding to the target pixel point, and obtaining the synthesized echo signal corresponding to the target pixel point. After completion The obtained data is called radio frequency signal data, also known as RF data. In this application, radio frequency signal refers to the signal with the probe receiving clock frequency, and the carrier frequency is just in the radio frequency band of the communication field, so it is called radio frequency signal.

S12: Carry out signal processing to the radio frequency signal, obtain baseband signal;

Specifically, the signal carrier in the radio frequency signal is removed through IQ demodulation, and tissue structure information contained in the radio frequency signal is extracted; the tissue structure information is filtered to remove noise, and a baseband signal is obtained.

S13: Obtaining a B-mode ultrasonic image based on the baseband signal;

Calculate the intensity of the baseband signal and logarithmically compress the gray level of the baseband signal to the range that the human eye can adapt to, and then a frame of B-mode ultrasonic image that can be displayed can be obtained.

S14: Calculate obstacle position and obstacle outline based on B-mode ultrasonic image;

With reference to Fig. 4, step S14 comprises the following steps:

S140: record the first time node, the first time node is the time node when the alternating voltage is applied to the piezoelectric crystal 1;

S141: record the second time node, the second time node is the time of receiving the ultrasonic reflected wave;

S142: Calculate the difference between the first time node and the second time node as the time difference;

S143: Calculate the relative distance, obstacle position and obstacle contour according to the time difference and the ultrasonic transmission speed.

Wherein, the ultrasonic propagation velocity is 340m/s, the relative distance between the obstacle and the piezoelectric crystal 1 = the ultrasonic propagation velocity × the above-mentioned time difference, and the position of the obstacle is obtained by calculating the relative distance between the obstacle and the piezoelectric crystal 1, that is, when All piezoelectric crystals 1 transmit and receive ultrasonic signals, and the position and outline of the obstacle at the monitoring position can be obtained.

S2: controlling the machine tool to stop in response to the relative distance being less than the preset safety distance;

S3: In response to the relative distance being less than the preset safety distance, perform alarm work and display the dangerous area on the outline of the obstacle through a visual interface;

Specifically, the outline of the obstacle is displayed on a visual interface; the position on the outline of the obstacle whose relative distance is smaller than the safety distance is marked as a dangerous area to be highlighted. The marking method in this application is to mark the dangerous area of the obstacle in red .

S4: Execute an alarm-free timing operation in response to obtaining the alarm-free instruction.

With reference to Fig. 5, step S4 comprises the following steps:

S40: Obtaining from obtaining an alarm-free instruction;

S41: Perform alarm-free timing based on the preset alarm-free time;

During the alarm-free time, no alarm signal is issued;

Specifically, after the alarm signal occurs, the operator will stop the alarm after confirming the alarm-free status on the man-machine interface, and the CNC machine tool can continue to complete the action. At the same time, it will start counting based on the preset alarm-free time. , when the relative distance between an obstacle and the piezoelectric crystal 1 is less than the safety distance, no alarm signal will be issued and the movement of the machine tool will not be prevented. At this time, it can be used by the operator to adjust the workpiece position and other operations.

When the alarm-free time is exceeded, and when the relative distance is less than the safety distance, an alarm signal is sent and the machine tool is controlled to stop.

The implementation principle of a monitoring method for anti-collision of a numerically controlled machine tool in the embodiment of the present application is as follows: a plurality of piezoelectric crystals 1 are implanted in the main shaft 3 of the machine tool, and an alternating voltage is applied to the piezoelectric crystal 1 to generate ultrasonic waves. Propagate along a straight line, and the ultrasonic wave is reflected after encountering an obstacle to form an ultrasonic reflected wave. Data and signal processing are performed on the ultrasonic reflected wave, and the relative distance, obstacle position and obstacle contour are calculated according to the time difference and ultrasonic transmission speed. When the relative distance between the contour of the obstacle and the piezoelectric crystal 1 is less than the preset safety distance, the machine tool is controlled to stop and give an alarm.

During the machining operation of the CNC machine tool, monitor the environment around the tool in real time, reduce the phenomenon of tool damage caused by obstacles colliding with the tool, and the application can reduce the phenomenon of mechanical structure problems of the CNC machine tool caused by serious tool collision events;

The shape of the piezoelectric crystal 1 is small, and multiple piezoelectric crystals 1 are implanted into the spindle 3 at the same time without occupying the machining space of the machine tool, affecting the shape of the machine tool, and not damaging the mechanical stability;

At the same time, as a high-frequency sound wave, ultrasonic waves have good stability, are less affected by the environment, and are not affected by factors such as poor light inside the CNC machine tool, making monitoring more accurate.

The operator can stop the alarm after confirming the alarm-free on the human-computer interaction interface, and make the machine tool continue to work, and at the same time perform the alarm-free timing. When the distance is less than the safety distance, no alarm signal will be issued and the movement of the machine tool will not be prevented. At this time, it can be used by the operator to adjust the workpiece position and other operations. And the alarm signal is uploaded to the upper computer, and the on-site operators can perform remote operations, and through the visual interface, the operation of the entire monitoring system is intuitive and clear.

The embodiment of the present application also discloses a monitoring system for anti-collision of CNC machine tools, including: a detection module, which is used to obtain the contour of obstacles and the relative relationship between the contour of the tool and the obstacle based on a number of piezoelectric crystals 1 preset at the tool. distance; a safety judgment module, configured to control the machine tool to stop in response to the relative distance being less than a preset safety distance.

The implementation principle of a monitoring system for anti-collision of CNC machine tools in the embodiment of the present application is: through the detection module, obtain the obstacle contour and the relative distance between the tool and the obstacle contour to calculate the obstacle position and obstacle contour; The module is used to control the stop of the machine tool in response to the relative distance being less than the preset safety distance, so as to achieve the function of real-time monitoring of the surrounding environment of the tool during the machining operation of the CNC machine tool, and reduce the phenomenon of tool damage caused by obstacles colliding with the tool , and can reduce the occurrence of problems in the mechanical structure of the CNC machine tool due to serious tool collision events.

The embodiment of the present application also discloses a terminal device, including a memory, a processor, and a computer program stored in the memory and capable of running on the processor, wherein, when the processor executes the computer program, the CNC machine tool anti-collision of the above-mentioned embodiment is used Use monitoring methods.

Wherein, the terminal device may be a computer device such as a desktop computer, a notebook computer, or a cloud server, and the terminal device includes but is not limited to a processor and a memory, for example, the terminal device may also include an input and output device, a network access device, and a bus.

Wherein, processor can adopt central processing unit (CPU), certainly, also can adopt other general-purpose processor, digital signal processor (DSP), application-specific integrated circuit (ASIC), off-the-shelf programmable gate array ( FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc., general-purpose processors can be microprocessors or any conventional processors, etc., and this application does not limit this.

Wherein, the memory may be an internal storage unit of the terminal device, for example, a hard disk or internal memory of the terminal device, or may be an external storage device of the terminal device, for example, a plug-in hard disk, a smart memory card (SMC), A secure digital card (SD) or a flash memory card (FC), etc., and the memory can also be a combination of an internal storage unit of the terminal device and an external storage device, and the memory is used to store computer programs and other programs and data required by the terminal device. The memory can also be used to temporarily store outputted or to-be-outputted data, which is not limited in the present application.

Wherein, through this terminal device, the monitoring method for anti-collision of CNC machine tools in the above embodiments is stored in the memory of the terminal device, and is loaded and executed on the processor of the terminal device for the convenience of users.

The embodiment of the present application also discloses a computer-readable storage medium, and the computer-readable storage medium stores a computer program, wherein, when the computer program is executed by a processor, the method for monitoring the collision avoidance of a CNC machine tool in the above-mentioned embodiment is adopted.

Among them, the computer program can be stored in a computer-readable medium, the computer program includes computer program code, and the computer program code can be in the form of source code, object code, executable file or some middleware, etc. Any entity or device carrying computer program code, recording medium, USB flash drive, removable hard disk, magnetic disk, optical disk, computer memory, read-only memory (ROM), random-access memory (RAM), electrical carrier signal, telecommunication signal and software It should be noted that the computer-readable medium includes but is not limited to the above components.

Wherein, the computer-readable storage medium stores the anti-collision monitoring method of the numerical control machine tool in the above-mentioned embodiment in the computer-readable storage medium, and is loaded and executed on the processor to facilitate the anti-collision monitoring of the numerical control machine tool Method storage and application.

All of the above are preferred embodiments of the present application, and are not intended to limit the protection scope of the present application. Any feature disclosed in this specification (including the abstract and accompanying drawings), unless specifically stated, can be used by other equivalents or similar Alternative features for the purpose are replaced. That is, unless expressly stated otherwise, each feature is one example only of a series of equivalent or similar features.

Claims (10)

1. The anti-collision monitoring method for the numerical control machine tool is characterized by comprising the following steps of:

acquiring an obstacle profile and a relative distance between a cutter and the obstacle profile based on a plurality of piezoelectric crystals (1) preset at the cutter;

and controlling the machine tool to stop acting in response to the relative distance being smaller than a preset safe distance.

2. The monitoring method for collision avoidance of numerical control machine according to claim 1, wherein said step of obtaining the obstacle profile and the relative distance between the tool and the obstacle profile based on a plurality of piezoelectric crystals (1) preset at the tool comprises:

applying an alternating voltage to the piezoelectric crystal (1) to cause the piezoelectric crystal (1) to emit ultrasonic waves;

acquiring ultrasonic reflected waves based on the piezoelectric crystal (1), and performing data processing on the ultrasonic reflected waves to obtain radio frequency signals;

performing signal processing on the radio frequency signal to obtain a baseband signal; obtaining a B-mode ultrasonic image based on the baseband signal;

calculating the obstacle position and the obstacle contour based on the B-mode ultrasonic image.

3. The anti-collision monitoring method for the numerical control machine tool according to claim 2, wherein the step of obtaining the ultrasonic reflection waves based on the ultrasonic waves and performing data processing on the ultrasonic reflection waves to obtain radio frequency signals comprises:

performing time gain compensation on the ultrasonic reflected wave;

converting the ultrasonic reflected wave into a digital signal;

and carrying out digital wave synthesis on the digital signals to form scanning line data and using the scanning line data as the radio frequency signals.

4. The collision avoidance monitoring method for a numerically controlled machine tool according to claim 2 or 3, wherein said step of calculating said obstacle location from said plurality of frames of said B-mode ultrasound images comprises:

recording a first time node, the first time node being a time node of an alternating voltage applied to the piezoelectric crystal (1);

recording a second time node, wherein the second time node is the time for receiving the ultrasonic reflected wave;

calculating a difference between the first time node and the second time node as a time difference;

and calculating the relative distance, the position of the obstacle and the outline of the obstacle according to the time difference and the ultrasonic transmission speed.

5. The collision avoidance monitoring method for the numerical control machine tool according to claim 1, further comprising performing an alarm operation and displaying a danger area on the obstacle contour through a visual interface in response to the relative distance being less than a preset safety distance.

6. The anti-collision monitoring method for the numerical control machine tool according to claim 5, further comprising: and executing the alarm-free timing operation in response to obtaining the alarm-free instruction.

7. The anti-collision monitoring method for the numerical control machine tool according to claim 6, wherein the step of executing the alarm-free timing operation in response to obtaining the alarm-free command comprises:

obtaining an alarm-free instruction;

performing alarm-free timing based on preset alarm-free time;

in the alarm-free time, no alarm signal is sent out;

and when the alarm-free time is exceeded and the relative distance is smaller than the safe distance, sending an alarm signal and controlling the machine tool to stop acting.

8. A monitoring system for collision prevention of a numerically-controlled machine tool, wherein the monitoring method for collision prevention of the numerically-controlled machine tool according to any one of claims 1 to 7 is used, and comprises:

the detection module is used for acquiring an obstacle outline and a relative distance between a cutter and the obstacle outline based on a plurality of piezoelectric crystals (1) preset at the cutter;

and the safety judgment module is used for responding to the condition that the relative distance is smaller than the preset safety distance and controlling the machine tool to stop acting.

9. A terminal device comprising a memory, a processor and a computer program stored in the memory and capable of running on the processor, wherein the processor loads and executes the computer program, and the method for monitoring collision avoidance of a numerical control machine according to any one of claims 1 to 7 is used.

10. A computer-readable storage medium, in which a computer program is stored, wherein the computer program is loaded by a processor and executed, and the method for monitoring collision avoidance of a numerically controlled machine tool according to any one of claims 1 to 7 is used.

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