CN112577407B - Method and system for correcting parameter drift of capacitive sensor - Google Patents
Method and system for correcting parameter drift of capacitive sensor Download PDFInfo
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- 238000003698 laser cutting Methods 0.000 claims abstract description 26
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- 238000012937 correction Methods 0.000 claims description 10
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- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B7/00—Measuring arrangements characterised by the use of electric or magnetic techniques
- G01B7/02—Measuring arrangements characterised by the use of electric or magnetic techniques for measuring length, width or thickness
- G01B7/04—Measuring arrangements characterised by the use of electric or magnetic techniques for measuring length, width or thickness specially adapted for measuring length or width of objects while moving
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B21/00—Measuring arrangements or details thereof, where the measuring technique is not covered by the other groups of this subclass, unspecified or not relevant
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Abstract
The embodiment of the application belongs to the technical field of laser cutting control, and relates to a method and a system for correcting parameter drift of a capacitive sensor. The technical scheme provided by the application comprises the following steps: after the calibration process is finished, the Z axis is far away from the calibration point, and a first frequency far away from the position is obtained; in the spare time after the cutting of the current graph is finished in a cutting period, the Z axis is far away from the calibration point, and a second frequency far away from the position is obtained; calculating the difference value between the first frequency and the second frequency, and adding the difference value to the frequency corresponding to each calibration point; a new frequency distance curve is constructed over the cutting cycle to compensate for distance changes caused by changes in the capacitive sensor parameters. The detection distance change caused by parameter drift of the oscillation circuit component in the capacitance sensor is compensated, the height measurement deviation caused by component parameter change is compensated, the effect of stabilizing distance detection is achieved, the processing quality is effectively guaranteed, and the processing efficiency cannot be influenced by correcting in the cutting process.
Description
Technical Field
The application relates to a laser cutting control technology, in particular to a method and a system for correcting parameter drift of a capacitive sensor.
Background
In laser cutting numerically controlled machine tools, a capacitive sensor is usually used for detecting the distance from the cutting nozzle to the plate workpiece, and an important component in the capacitive sensor is a preamplifier circuit, usually an LC oscillation circuit, which converts the capacitance into an oscillation frequency related thereto. Due to the fact that parameters of analog devices of the LC oscillating circuit change, such as triode junction capacitance, inductance capacitance of the frequency selection circuit and other parasitic capacitances, the values of oscillation frequencies change along with the changes of temperature, humidity and the like, measurement results are inaccurate, particularly when the distance between a nozzle and a plate is large, the measurement results are more obvious, and if the measurement distance is small, the follow-up falling deceleration distance is insufficient, so that the overshoot collision plate is caused.
Disclosure of Invention
The invention aims to provide a method and a system for correcting parameter drift of a capacitive sensor, which compensate the detection distance change caused by parameter drift of oscillation circuit components in the capacitive sensor, compensate height measurement deviation caused by component parameter change, achieve the effect of stable distance detection, stabilize the distance measurement function of the capacitive sensor in the whole processing process, effectively ensure the processing quality, complete the whole process within the vacant time in a cutting period, and correct in the cutting process without influencing the processing efficiency.
In order to solve the above-mentioned problems, embodiments of the present invention provide the following technical solutions:
a method for correcting parameter drift of a capacitive sensor comprises the following steps:
after the calibration process is finished, the Z axis is far away from the calibration point, and a first frequency far away from the position is obtained;
in the spare time after the cutting of the current graph is finished in a cutting period, the Z axis is far away from the calibration point, and a second frequency far away from the position is obtained;
calculating the difference between the first frequency and the second frequency, and adding the difference to the frequency corresponding to each calibration point;
a new frequency distance curve is constructed over the cutting cycle to compensate for distance changes caused by changes in the capacitive sensor parameters.
Further, the step of acquiring a second frequency far from the position in the vacant time after the current graph is cut and when the Z axis is far from the calibration point includes:
after the cutting of the current graph is finished, judging whether a preset time interval far away from the calibration point is reached;
if the time interval is up, judging whether the difference value between the current Z-axis coordinate and the Z-axis positive limit coordinate is greater than the Z-axis preset lifting distance or not;
and if the difference value is greater than the preset lifting distance of the Z axis, executing a Z axis lifting command.
Further, if the difference is greater than a preset Z-axis lift distance, the step of executing a Z-axis lift command includes:
and after the preset lifting distance on the Z axis is lifted, sending a request of being far away from the calibration point to the lower computer.
Further, the step of obtaining the second frequency far from the position in the vacant time after the cutting of the current graph, in which the Z axis is far from the calibration point, further includes:
and receiving a request of keeping away from the calibration point, wherein the Z axis is kept away from the calibration point, and sampling the frequency of the current far position to be used as a second frequency of the current far position.
Further, the step of calculating a difference between the first frequency and the second frequency and adding the difference to the frequency corresponding to each calibration point includes:
calculating a difference between a first frequency and a second frequency, wherein the first frequency is f1, the second frequency is f2, and the difference df = f1-f2;
adding a difference df to the frequency corresponding to the index point of the current index to obtain a third frequency;
adding 1 to the index of the index point, and judging whether the index is finished;
if the indexing is finished, outputting the results of the third frequency of all the index points;
and if the index is not finished, returning to the step of adding the difference df to the frequency corresponding to the index point to obtain a third frequency.
Further, after the step of constructing a new frequency-distance curve in a cutting cycle to compensate for distance changes caused by parameter changes of the capacitive sensor, the method further includes:
and continuing to execute the cutting program of the next period and the rest periods.
Further, in the step of constructing a new frequency-distance curve in the cutting cycle, the frequency-distance curve is a curve of a distance from the laser cutting head to the workpiece to be machined and an oscillation frequency measured by the capacitive sensor.
Further, in the step of constructing a new frequency-distance curve in the cutting cycle, the frequency is an oscillation frequency, a capacitance value formed by the laser cutting head and the surface of the workpiece to be machined is detected by a capacitance sensor, the capacitance value is converted into the oscillation frequency, and the distance is the distance between the laser cutting head and the surface of the workpiece to be machined and is obtained according to the oscillation frequency.
Further, after the calibration process is finished, before the step of obtaining the first frequency of the far position by the Z axis far away from the calibration point, the method further includes:
controlling the laser cutting head to move towards the surface of the machined workpiece and waiting for a collision signal;
after detecting the collision signal, controlling the laser cutting head to move away from the surface of the processed workpiece, and waiting for the collision signal to disappear;
and setting a plurality of calibration points in the process of controlling the laser cutting head to move away from the surface of the machined workpiece, and recording the distance between the nozzle of the laser cutting head of each calibration point and the surface of the machined workpiece.
In order to solve the technical problem mentioned above, an embodiment of the present invention further provides a system for correcting parameter drift of a capacitive sensor, which adopts the following technical solutions:
a capacitive sensor parameter drift correction system, comprising:
the first acquisition module is used for acquiring a first frequency of a far position when the Z axis is far away from the calibration point after the calibration process is finished;
the second acquisition module is used for acquiring a second frequency far away from the position when the Z axis is far away from the calibration point in the spare time after the cutting of the current graph is finished in a cutting cycle;
the calculation module is used for calculating the difference value between the first frequency and the second frequency and adding the difference value to the frequency corresponding to each calibration point;
and the construction module is used for constructing a new frequency distance curve in the cutting period so as to compensate the distance change caused by the parameter change of the capacitive sensor.
Compared with the prior art, the embodiment of the invention mainly has the following beneficial effects:
a method and a system for correcting parameter drift of a capacitance sensor are provided, wherein a second frequency far away from a position is obtained in the spare time of a cutting period, a difference value between a stored first frequency and a current second frequency is calculated, the difference value is added to the frequency corresponding to each calibration point, a new frequency distance curve is constructed in the cutting period, the detection distance change caused by parameter drift of an oscillation circuit component in the capacitance sensor is compensated, the compensation operation of parameter change is carried out on the frequency distance curve of the capacitance at the machining clearance of a machine tool, the height measurement deviation caused by element parameter change is compensated, the effect of stable distance detection is achieved, the distance measurement function of the capacitance sensor in the whole machining process is stable, the machining quality is effectively ensured, the whole process is completed in the spare time of the cutting period, and the machining efficiency is not influenced by the correction in the cutting process.
Drawings
In order to illustrate the solution of the invention more clearly, the drawings that are needed in the description of the embodiments will be briefly described below, it being obvious that the drawings in the following description are some embodiments of the invention, and that other drawings may be derived from these drawings by a person skilled in the art without inventive effort.
FIG. 1 is a flow chart of a method for correcting drift in capacitive sensor parameters according to an embodiment of the present invention;
FIG. 2 is a schematic diagram of a frequency distance curve according to an embodiment of the present invention;
FIG. 3 is a flow chart of acquiring a second frequency at a remote location in an embodiment of the present invention;
FIG. 4 is a flowchart illustrating obtaining a third frequency of the calibration point according to an embodiment of the present invention;
fig. 5 is a block diagram of a system for correcting parameter drift of a capacitive sensor according to an embodiment of the present invention.
Description of the reference numerals:
100. a first acquisition module; 200. a second acquisition module; 300. a calculation module; 400. and constructing a module.
Detailed Description
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The terms "comprising" and "having," and any variations thereof, in the description and claims of the present invention and the description of the above figures are intended to cover non-exclusive inclusions. The terms "first," "second," and the like in the description and in the claims, or in the drawings, are used for distinguishing between different objects and not necessarily for describing a particular sequential order.
Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the invention. The appearances of the phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. It is explicitly and implicitly understood by one skilled in the art that the embodiments described herein may be combined with other embodiments.
The embodiment of the application provides a method for correcting parameter drift of a capacitive sensor, which comprises the following steps:
after the calibration process is finished, the Z axis is far away from the calibration point, and a first frequency far away from the position is obtained;
in the spare time after the cutting of the current graph is finished in a cutting period, the Z axis is far away from the calibration point, and a second frequency far away from the position is obtained;
calculating the difference value between the first frequency and the second frequency, and adding the difference value to the frequency corresponding to each calibration point;
a new frequency distance curve is constructed over the cutting cycle to compensate for distance changes caused by changes in the capacitive sensor parameters.
Based on the foregoing method for correcting parameter drift of a capacitive sensor, an embodiment of the present application further provides a system for correcting parameter drift of a capacitive sensor, including:
the first acquisition module is used for acquiring a first frequency of a far position when the Z axis is far away from the calibration point after the calibration process is finished;
the second acquisition module is used for acquiring a second frequency far away from the position when the Z axis is far away from the calibration point in the spare time after the cutting of the current graph is finished in a cutting cycle;
the calculation module is used for calculating the difference value between the first frequency and the second frequency and adding the difference value to the frequency corresponding to each calibration point;
and the construction module is used for constructing a new frequency distance curve in the cutting period so as to compensate the distance change caused by the parameter change of the capacitive sensor.
In order to make the technical solutions of the present invention better understood by those skilled in the art, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the relevant drawings.
Examples
A method for correcting parameter drift of a capacitive sensor, as shown in fig. 1, includes the following steps:
s100, after the calibration process is finished, enabling the Z axis to be far away from the calibration point, and acquiring a first frequency far away from the position;
s200, in a vacant time after the cutting of the current graph is finished in a cutting period, the Z axis is far away from the calibration point, and a second frequency far away from the position is obtained;
s300, calculating the difference value between the first frequency and the second frequency, and adding the difference value to the frequency corresponding to each calibration point;
and S400, constructing a new frequency distance curve in a cutting period so as to compensate distance change caused by parameter change of the capacitive sensor.
Specifically, a plurality of calibration points are set, in the embodiment of the present invention, 16 calibration points are set, after 16 calibration points are calibrated, the Z axis is far away from the calibration points, the Z axis is lifted to a point 0, that is, a far position, and whether the calibration process and the result are normal is determined, if the calibration process and the result are normal, the frequency at the point 0, that is, the first frequency is obtained, and the first frequency is stored in the flying wing type storage medium.
In a cutting cycle, within the spare time after the cutting of the current graph is completed, the Z axis is far away from the calibration point, the spare time in the cutting cycle is the time when a graph is cut and the lifting action is executed, at the moment, the Z axis is lifted for a certain distance, for example, lifted by 50mm, the operation of the request far away from the calibration point is executed, then the frequency of the current position is sampled, and the second frequency far away from the position is obtained.
And then calculating the difference value between the stored first frequency and the current second frequency, adding the difference value to the frequency corresponding to each calibration point, and constructing a new frequency distance curve in a cutting period to compensate the detection distance change caused by parameter drift of oscillation circuit components in the capacitive sensor.
According to the parameter drift correction method for the capacitive sensor, provided by the embodiment of the invention, the second frequency far away from the position is obtained in the spare time of a cutting cycle, the difference value between the stored first frequency and the current second frequency is calculated, the difference value is added to the frequency corresponding to each calibration point, a new frequency distance curve is constructed in the cutting cycle, the detection distance change caused by parameter drift of an oscillation circuit component in the capacitive sensor is compensated, the compensation operation of parameter change is carried out on the frequency distance curve of the capacitor at the machining clearance of a machine tool, the height measurement deviation caused by element parameter change is compensated, the effect of stable distance detection is achieved, the distance measurement function of the capacitive sensor in the whole machining process is stable, the machining quality is effectively ensured, the whole process is completed in the spare time of the cutting cycle, and the machining efficiency is not influenced by the correction in the cutting process.
An LC oscillating circuit is adopted in a front-end circuit for measuring capacitance in the capacitance sensor, and the frequency stability of the LC oscillating circuit is not too high due to the limitation of loop standard, and is generally 10 -4 In particular, in a laser cutting working place, the environment where the capacitance sensor is located is generally harsh, and when the environmental temperature, humidity and the like change, the capacitance sensor sensesThe required frequency stability is worse.
As shown in fig. 2, the distance between the nozzle of the laser cutting head and the surface of the workpiece to be machined and the oscillation frequency are plotted, when the circuit parameters drift, the oscillation frequency changes, the frequency value at the same distance is different, and the overall plot moves up and down.
Because the same frequency value is changed in the curve, the corresponding distance is changed, and adverse effects such as cutting height change are caused. In order to compensate for a change in distance detection due to parameter drift, it is necessary to correct the frequency-distance curve.
As shown in fig. 3, in S200, in a free time after the cutting of the current graph is completed in a cutting cycle, the step of obtaining the second frequency of the far position includes:
s210: after the cutting of the current graph is finished, judging whether a preset time interval far away from the calibration point is reached;
s220: if the time interval is up, judging whether the difference value between the current Z-axis coordinate and the Z-axis positive limit coordinate is greater than the Z-axis preset lifting distance or not;
and S230, if the difference value is greater than the preset lifting distance of the Z axis, executing a Z axis lifting command.
Specifically, after the cutting of the current graph is completed, before the step of determining whether a preset time interval is reached after the current graph is cut, the method further includes: and in the cutting process, judging whether the current cutting graph is cut completely. If the cutting is finished, judging whether a preset time interval away from the calibration point is reached, wherein the preset time interval is a configurable parameter, if the time interval is reached, judging whether the lifting distance is enough, and judging whether the difference value between the current Z-axis coordinate and the Z-axis positive limit coordinate is larger than the distance to be lifted, in the embodiment, the preset lifting distance is 50mm, and if the difference value is larger than 50mm, executing the operation of lifting the Z axis by 50 mm.
If the difference value is greater than the preset lifting distance of the Z axis, the step of executing the Z axis lifting command comprises the following steps: and after the preset uplifting distance is uplifted on the Z axis, sending a request of being far away from the calibration point to the lower computer.
And sending a request far away from calibration to the lower computer, finishing curve reconstruction by the lower computer in a cutting period after the request is sent, and then continuously executing the rest cutting programs. And in the step of acquiring a second frequency of a far position when the Z axis is far away from the calibration point within the vacant time after the current graph is cut, if the time interval is not reached or the difference value is not greater than the preset lifting distance of the Z axis, the operation of sending the far calibration request by lifting is not executed, and the cutting program is continuously executed.
S200, in the spare time after the current graph is cut, the Z axis is far away from the calibration point, and the step of obtaining the second frequency far away from the position further comprises the following steps:
and receiving a request of keeping away from the calibration point, wherein the Z axis is far away from the calibration point, and sampling the frequency of the current far position as a second frequency of the current far position.
After the Z axis is far away from the calibration point, the lower computer receives the compensation request, and firstly samples the frequency value of the current position as a second frequency of the current far position.
As shown in fig. 4, in S300, the step of calculating a difference between the first frequency and the second frequency and adding the difference to the frequency corresponding to each calibration point includes:
s310, calculating a difference value between a first frequency and a second frequency, wherein the first frequency is f1, the second frequency is f2, and the difference value df = f1-f2;
s320, adding a difference df to the frequency corresponding to the index point of the current index to obtain a third frequency;
s330, adding 1 to the index of the index point, and judging whether the index is finished;
s340, if the indexing is finished, outputting the results of the third frequency of all the index points;
and S350, if the indexing is not finished, returning to the step of adding the difference df to the frequency corresponding to the index point to obtain a third frequency.
And constructing a new frequency distance curve in a cutting period according to the third frequency of all the calibration points so as to compensate the distance change caused by the parameter change of the capacitive sensor.
In the step of constructing a new frequency distance curve in the cutting period, the frequency distance curve is a curve of the distance from the laser cutting head to the processed workpiece and the oscillation frequency measured by the capacitance sensor.
In S400, after a new frequency-distance curve is constructed in a cutting cycle to compensate for a distance change caused by a parameter change of the capacitive sensor, the method further includes:
and continuing to execute the cutting program of the next period and the rest periods.
In the step of constructing a new frequency-distance curve in the cutting period, the frequency is oscillation frequency, a capacitance value formed by the laser cutting head and the surface of the workpiece to be machined is detected through a capacitance sensor, the capacitance value is converted into oscillation frequency, and the distance is the distance between the laser cutting head and the surface of the workpiece to be machined and is obtained according to the oscillation frequency.
The S100, after the calibration process is finished, before the step of obtaining the first frequency of the far position when the Z axis is far from the calibration point, further includes:
controlling the laser cutting head to move towards the surface of the machined workpiece and waiting for a collision signal;
after detecting the collision signal, controlling the laser cutting head to move away from the surface of the processed workpiece, and waiting for the collision signal to disappear;
and setting a plurality of calibration points in the process of controlling the laser cutting head to move away from the surface of the machined workpiece, and recording the distance between the nozzle of the laser cutting head of each calibration point and the surface of the machined workpiece.
Specifically, firstly, the numerical control unit controls the height adjusting shaft to slowly move downwards to wait for a collision signal, when the collision signal is received, the numerical control unit slowly moves upwards to wait for the collision signal to disappear, then according to the set 16 calibration points, the numerical control unit sends a calibration request signal to the signal conditioner when moving the height adjusting shaft to one calibration point, the signal conditioner sends a calibration confirmation signal to the numerical control unit after recording the numerical value (the distance between the nozzle of the laser cutting head and the surface of the processed workpiece) of the calibration point, the numerical control unit controls the height adjusting shaft to move towards the next calibration point, and the signal conditioner checks the calibrated data after the calibration is finished.
According to the parameter drift correction method for the capacitive sensor, provided by the embodiment of the invention, the second frequency f2 far away from the position is obtained in the vacant time of a cutting period, the difference df between the stored first frequency f1 and the current second frequency f2 is calculated, the difference df is added to the frequency corresponding to each calibration point to obtain a third frequency, a new frequency distance curve is constructed according to the third frequencies of all the calibration points in the cutting period, the detection distance change caused by parameter drift of an oscillating circuit component in the capacitive sensor is compensated, the compensation operation of parameter change is carried out on the frequency distance curve of the capacitor in a machining gap of a machine tool, the height measurement deviation caused by component parameter change is compensated, the effect of stable distance detection is achieved, the distance measurement function of the capacitive sensor in the whole machining process is stable, the machining quality is effectively ensured, the whole process is completed in the vacant time of the cutting period, and the correction in the cutting process does not influence the machining efficiency.
In order to solve the technical problem mentioned above, an embodiment of the present invention further provides a system for correcting parameter drift of a capacitive sensor, which adopts the following technical solutions:
a capacitive sensor parameter drift correction system, as shown in fig. 5, comprising:
the first obtaining module 100 is configured to, after the calibration process is finished, obtain a first frequency of a far position by the Z axis being far from the calibration point;
the second obtaining module 200 is configured to obtain a second frequency of a position far away from the calibration point in a vacant time after the cutting of the current graph is completed in a cutting cycle, where the Z axis is far away from the calibration point;
a calculating module 300, configured to calculate a difference between the first frequency and the second frequency, and add the difference to the frequency corresponding to each calibration point;
a construction module 400 for constructing a new frequency distance curve during a cutting cycle to compensate for distance changes caused by changes in capacitive sensor parameters.
According to the parameter drift correction system for the capacitive sensor, provided by the embodiment of the invention, the second frequency far away from the position is obtained in the spare time of a cutting cycle, the difference value between the stored first frequency and the current second frequency is calculated, the difference value is added to the frequency corresponding to each calibration point, a new frequency distance curve is constructed in the cutting cycle, the detection distance change caused by parameter drift of an oscillation circuit component in the capacitive sensor is compensated, the compensation operation of parameter change is carried out on the frequency distance curve of the capacitor at the machining clearance of a machine tool, the height measurement deviation caused by element parameter change is compensated, the effect of stable distance detection is achieved, the distance measurement function of the capacitive sensor in the whole machining process is stable, the machining quality is effectively ensured, the whole process is completed in the spare time of the cutting cycle, and the machining efficiency is not influenced by the correction in the cutting process.
It is to be understood that the above-described embodiments are merely illustrative of some, but not restrictive, of the broad invention, and that the appended drawings illustrate preferred embodiments of the invention without limiting its scope. This invention may be embodied in many different forms and, on the contrary, these embodiments are provided so that this disclosure will be thorough and complete. Although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that various changes in the embodiments and modifications can be made, and equivalents may be substituted for elements thereof. All equivalent structures made by using the contents of the specification and the attached drawings of the invention can be directly or indirectly applied to other related technical fields, and are also within the protection scope of the patent of the invention.
Claims (10)
1. A method for correcting parameter drift of a capacitive sensor is characterized by comprising the following steps:
after the calibration process is finished, the Z axis is far away from the calibration point, and a first frequency far away from the position is obtained;
in the spare time after the cutting of the current graph is finished in a cutting period, the Z axis is far away from the calibration point, and a second frequency far away from the position is obtained;
calculating the difference between the first frequency and the second frequency, and adding the difference to the frequency corresponding to each calibration point;
a new frequency-distance curve is constructed over the cutting cycle to compensate for distance changes caused by changes in the capacitive sensor parameters.
2. The method according to claim 1, wherein the step of acquiring the second frequency of the distant position when the Z-axis is distant from the calibration point within the free time after the cutting of the current pattern is completed comprises:
after the cutting of the current graph is finished, judging whether a preset time interval far away from the calibration point is reached;
if the time interval is up, judging whether the difference value of the current Z-axis coordinate and the Z-axis positive limit coordinate is greater than the preset lifting distance of the Z axis;
and if the difference value is greater than the preset lifting distance of the Z axis, executing a Z axis lifting command.
3. The method of claim 2, wherein if the difference is greater than a predetermined Z-axis lift-off distance, the step of executing a Z-axis lift-off command comprises:
and after the preset uplifting distance is uplifted on the Z axis, sending a request of being far away from the calibration point to the lower computer.
4. The method of claim 3, wherein the step of acquiring a second frequency of the distant location within the free time after the cutting of the current pattern, wherein the Z-axis is distant from the calibration point, further comprises:
and receiving a request of keeping away from the calibration point, wherein the Z axis is far away from the calibration point, and sampling the frequency of the current far position as a second frequency of the current far position.
5. The method of claim 1, wherein the step of calculating a difference between the first frequency and the second frequency and adding the difference to the frequency corresponding to each calibration point comprises:
calculating a difference between a first frequency and a second frequency, wherein the first frequency is f1, the second frequency is f2, and the difference df = f1-f2;
adding a difference df to the frequency corresponding to the index point of the current index to obtain a third frequency;
adding 1 to the index of the index point, and judging whether the index is finished;
if the indexing is finished, outputting the results of the third frequency of all the index points;
and if the index is not finished, returning to the step of adding the difference df to the frequency corresponding to the index point to obtain a third frequency.
6. The method for correcting parameter drift of a capacitive sensor according to claim 1, wherein after the step of constructing a new frequency-distance curve during a cutting cycle to compensate for distance variation caused by parameter variation of the capacitive sensor, the method further comprises:
and continuing to execute the cutting program of the next period and the rest periods.
7. The method of claim 1, wherein the step of constructing a new frequency-distance curve during the cutting cycle is a curve of a distance from the laser cutting head to the workpiece to be machined and an oscillation frequency measured by the capacitive sensor.
8. The method according to claim 7, wherein in the step of constructing a new frequency-distance curve during the cutting cycle, the frequency is an oscillation frequency, a capacitance value formed by the laser cutting head and the surface of the workpiece to be machined is detected by the capacitive sensor and converted into the oscillation frequency, and the distance is obtained according to the oscillation frequency.
9. The method according to claim 1, wherein before the step of obtaining the first frequency of the remote location after the calibration process with the Z-axis away from the calibration point, the method further comprises:
controlling the laser cutting head to move towards the surface of the machined workpiece and waiting for a collision signal;
after detecting the collision signal, controlling the laser cutting head to move away from the surface of the processed workpiece, and waiting for the collision signal to disappear;
and setting a plurality of calibration points in the process of controlling the laser cutting head to move away from the surface of the machined workpiece, and recording the distance between the nozzle of the laser cutting head of each calibration point and the surface of the machined workpiece.
10. A capacitive sensor parameter drift correction system, comprising:
the first acquisition module is used for acquiring a first frequency of a far position when the Z axis is far away from the calibration point after the calibration process is finished;
the second acquisition module is used for acquiring a second frequency far away from the position when the Z axis is far away from the calibration point in the spare time after the cutting of the current graph is finished in a cutting cycle;
the calculation module is used for calculating the difference value between the first frequency and the second frequency and adding the difference value to the frequency corresponding to each calibration point;
and the construction module is used for constructing a new frequency distance curve in the cutting period so as to compensate the distance change caused by the parameter change of the capacitive sensor.
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