CN110039190B - Laser cutting control method and device and computer readable storage medium - Google Patents
Laser cutting control method and device and computer readable storage medium Download PDFInfo
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- CN110039190B CN110039190B CN201910266907.5A CN201910266907A CN110039190B CN 110039190 B CN110039190 B CN 110039190B CN 201910266907 A CN201910266907 A CN 201910266907A CN 110039190 B CN110039190 B CN 110039190B
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K26/00—Working by laser beam, e.g. welding, cutting or boring
- B23K26/36—Removing material
- B23K26/38—Removing material by boring or cutting
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K26/00—Working by laser beam, e.g. welding, cutting or boring
- B23K26/70—Auxiliary operations or equipment
- B23K26/702—Auxiliary equipment
Abstract
The embodiment of the invention discloses a laser cutting control method, a laser cutting control device and a computer readable storage medium, wherein in the process of cutting a workpiece, an actual voltage value U fed back by a sensor based on the height of the bottom of a cutting head from the surface of the workpiece is obtainedACT(ii) a Calculate UACTAnd a target voltage value USETDifference value U betweenDIF(ii) a According to UDIFControlling the cutting head to move, and adjusting the height of the cutting head from the surface of the workpiece until the height is based on the real-time acquired UACTDetermining UDIFIs zero. By implementing the method, the height of the cutting head from the surface of the workpiece is controlled in a follow-up manner only by taking the pressure difference between the real-time feedback voltage of the sensor and the voltage corresponding to the target height as a control quantity in the laser cutting process, the algorithm complexity is low, the method does not need to depend on a corresponding curve of a voltage value and a distance and is not influenced by the degradation of a calibration curve, and the control stability and the safety are high.
Description
Technical Field
The present invention relates to the field of laser processing, and in particular, to a laser cutting control method and apparatus, and a computer-readable storage medium.
Background
Laser cutting is a non-contact process in which a laser is focused by a laser cutting head onto a surface of a workpiece for thermal processing, and the distance between the laser cutting head and the surface of the workpiece is an important control. The surface of the workpiece to be machined is often not perfectly flat and during the cutting process, the workpiece is prone to deformation, resulting in surface undulations of the workpiece. In order to ensure that the laser focus is kept focused on the surface of the workpiece, a specific distance between the laser cutting head and the surface of the plate is required to be kept unchanged in the whole machining process, so that the laser cutting head needs to be subjected to follow-up control on the Z axis according to feedback of the distance between the laser cutting head and the surface of the workpiece.
Currently, when the laser cutting head is controlled to follow up in the Z axis, a capacitance sensor is generally used to collect a voltage value related to a distance, and then a current distance is determined based on a corresponding relationship between the voltage value and the distance, and then a height of the laser cutting head from a surface of a workpiece is adjusted based on the determined distance. In the related art, a PID algorithm is usually adopted to dynamically compensate for the distance error, however, complex speed planning is required in algorithm implementation, and the involved parameters are more, so that the algorithm complexity is high; in addition, the control based on the PID algorithm belongs to a predictive control, and the current distance needs to be determined strictly depending on a corresponding curve of a voltage value and a distance, however, in practical application, the calibration curve can be degraded due to the fact that a sensor is heated, blown, slag spraying and the like, although the degraded distance and the voltage relation are still in direct proportion, the slope of the curve is changed, as shown in fig. 1, the calibration curve is a schematic diagram under normal conditions, as shown in fig. 2, the calibration curve is a schematic diagram after degradation, if the calibration curve is degraded, the degraded calibration curve is taken as a control reference, situations such as overshoot and collision between a laser cutting head and the surface of a workpiece can be caused, and the control stability and the safety are low.
Disclosure of Invention
The embodiments of the present invention mainly aim to provide a laser cutting control method, device and computer readable storage medium, which can at least solve the problems of high algorithm complexity, and low control stability and safety caused by the following control of the height of a laser cutting head from the surface of a workpiece based on a PID algorithm and a corresponding curve of a voltage value and a distance in the related art.
In order to achieve the above object, a first aspect of the embodiments of the present invention provides a laser cutting control method, including:
in the process of cutting a workpiece to be cut, acquiring an actual voltage value U fed back by a capacitance sensor based on the height of the bottom of a laser cutting head from the surface of the workpiece to be cutACT；
Calculating the UACTAnd a target voltage value USETDifference value U betweenDIF(ii) a The U isSETWhen the height from the bottom of the laser cutting head to the surface of the workpiece to be cut is a preset target height, the corresponding voltage value is obtained;
according to the UDIFControlling the laser cutting head to move, and adjusting the height of the laser cutting head from the surface of the workpiece to be cut until the U is acquired in real timeACTDetermining the UDIFIs zero.
In order to achieve the above object, a second aspect of embodiments of the present invention provides a laser cutting control apparatus, including:
an acquisition module used for acquiring an actual voltage value U fed back by the capacitance sensor based on the height of the bottom of the laser cutting head from the surface of the workpiece to be cut in the process of cutting the workpiece to be cutACT；
A calculation module for calculating the UACTAnd a target voltage value USETDifference value U betweenDIF(ii) a The U isSETWhen the height from the bottom of the laser cutting head to the surface of the workpiece to be cut is a preset target height, the corresponding voltage value is obtained;
a control module for controlling the current according to the UDIFControlling the laser cutting head to move, and adjusting the height of the laser cutting head from the surface of the workpiece to be cut until the U is acquired in real timeACTDetermining the UDIFIs zero.
To achieve the above object, a third aspect of embodiments of the present invention provides an electronic apparatus, including: a processor, a memory, and a communication bus;
the communication bus is used for realizing connection communication between the processor and the memory;
the processor is configured to execute one or more programs stored in the memory to implement the steps of any of the above-mentioned laser cutting control methods.
In order to achieve the above object, a fourth aspect of the embodiments of the present invention provides a computer-readable storage medium storing one or more programs, which are executable by one or more processors to implement the steps of any one of the above-mentioned laser cutting control methods.
According to the laser cutting control method and device and the computer-readable storage medium provided by the embodiment of the invention, in the process of cutting the workpiece to be cut, the actual voltage value U fed back by the capacitance sensor based on the height of the bottom of the laser cutting head from the surface of the workpiece to be cut is obtainedACT(ii) a Calculate UACTAnd a set target voltage value USETDifference value U betweenDIF(ii) a According to UDIFControlling the laser cutting head to move, and adjusting the height of the laser cutting head from the surface of the workpiece to be cut until the height is based on the real-time acquired UACTDetermining UDIFIs zero. By implementing the method, the height of the laser cutting head from the surface of the workpiece is controlled in a follow-up manner only by taking the voltage difference between the real-time feedback voltage of the capacitance sensor and the voltage corresponding to the target height as a control quantity in the laser cutting process, the algorithm complexity is low, the method does not need to depend on the corresponding curve of the voltage value and the distance, the influence of the degradation of a calibration curve is avoided, and the control stability and the safety are high.
Other features and corresponding effects of the present invention are set forth in the following portions of the specification, and it should be understood that at least some of the effects are apparent from the description of the present invention.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
FIG. 1 is a diagram illustrating a calibration curve of voltage value versus distance under normal conditions in the related art;
FIG. 2 is a schematic diagram of a calibration curve of voltage value and distance after curve degradation in the related art
Fig. 3 is a schematic basic flowchart of a laser cutting control method according to a first embodiment of the present invention;
FIG. 4 is a schematic view of a laser cutting process according to a first embodiment of the present invention;
FIG. 5 is a diagram illustrating a relationship between a Z-axis position curve and a speed curve of a laser cutting head according to a first embodiment of the present invention;
fig. 6 is a schematic structural diagram of a laser cutting control device according to a second embodiment of the present invention;
fig. 7 is a schematic structural diagram of an electronic device according to a third embodiment of the invention.
Detailed Description
In order to make the objects, features and advantages of the present invention more obvious and understandable, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is apparent that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The first embodiment:
in order to solve the technical problems of higher algorithm complexity, lower control stability and lower safety caused by the following control of the height of the laser cutting head from the surface of the workpiece based on the PID algorithm and the corresponding curve of the voltage value and the distance in the related art, the present embodiment provides a laser cutting control method, and as shown in fig. 3, the basic flow diagram of the laser cutting control method provided by the present embodiment is provided, and the laser cutting control method provided by the present embodiment includes the following steps:
301, in the process of cutting the workpiece to be cut, acquiring an actual voltage value U fed back by a capacitance sensor based on the height of the bottom of a laser cutting head from the surface of the workpiece to be cutACT。
As shown in fig. 4, which is a schematic view of laser cutting provided in this embodiment, the height of the focal point in this embodiment is a vertical distance between the laser focal point and a surface of a workpiece to be cut, the set height is a vertical distance between the bottom of the laser cutting head and the surface of the workpiece to be cut when the height of the focal point is maintained, and the set height is a target height meeting requirements of a laser cutting process. In an implementation manner of this embodiment, the capacitive sensor may be implemented by using a specific area at the bottom of the laser cutting head as an anode of a capacitor, and using a workpiece to be cut as a cathode of the capacitor, so as to form a capacitive sensor for measuring a distance, in practical applications, a measurement range of the capacitive sensor may be 0-20mm, and a voltage value fed back to the control system is correspondingly 0-10V, where the distance is positively correlated with the voltage value. In addition, it should be understood that the actual voltage value in this embodiment is a voltage value collected by the capacitance sensor in real time, and corresponds to a current real-time height of the bottom of the laser cutting head from the surface of the workpiece to be cut.
Optionally, the actual voltage value U fed back by the capacitance sensor based on the height of the bottom of the laser cutting head from the surface of the workpiece to be cut is obtainedACTBefore, still include: when the laser cutting is started to align the laser cutting head, the alignment adjustment process is planned to be an acceleration adjustment stage, a constant speed adjustment stage and a deceleration adjustment stage in sequence, and a starting point P2 and an end point P4 of the constant speed adjustment stage are determined; in the acceleration adjustment stage, the height from the bottom of the laser cutting head to the surface of the workpiece to be cut is larger than the range of the capacitance sensor; controlling the laser cutting head to perform acceleration adjustment between the starting points P1 and P2 of the alignment adjustment, controlling the laser cutting head to perform uniform speed adjustment between P2 and P4, and then controlling the laser cutting head to perform deceleration adjustment from P4 until the U is obtained in real timeACTDetermining UDIFAnd the zero value is reached, the end point P5 of the deceleration adjusting stage is reached, and the alignment adjustment is finished, so that the laser cutting head reaches the target height.
Specifically, in this embodiment, before the laser cutting of the workpiece to be cut is started, the position of the laser cutting head needs to be initialized first, that is, the laser cutting head is aligned to the target positionTo a height that meets the process requirements, subsequent laser cutting is then initiated. In this embodiment, in order to ensure the efficiency and accuracy of laser cutting head alignment, the movement speed of the laser cutting head during the alignment adjustment process is planned, as shown in fig. 5, which is a schematic diagram of a corresponding relationship between a Z-axis position curve and a speed curve of the laser cutting head provided in this embodiment, the whole alignment adjustment stage of the laser cutting head is divided into an acceleration adjustment process of P1-P2, a uniform adjustment process of P2-P4, and a uniform adjustment process of P4-P5, which respectively correspond to the speed VzOr differential pressure UDIFIn three stages of curves P1 '-P2', P2 '-P4' and P4 '-P5', the following initial height in the figure is the height of the bottom of the laser cutting head from the workpiece to be cut before the laser cutting head is aligned, and the height of the laser cutting head moving in the alignment adjustment process is subtracted from the following initial height, namely the preset target height (set height). It should be noted that the position of point P2 in this embodiment is determined based on the maximum speed that the laser cutting head is to achieve during adjustment.
Optionally, determining P4 of the uniform speed adjustment phase includes: determining the minimum value (D) of the deceleration distance corresponding to the deceleration adjustment phaseDCC) min; to (D)DCC) min is subjected to allowance reservation processing to obtain a target deceleration distance DDCCThe margin reservation processing formula can be expressed as: dDCC＝(DDCC) min/alpha, alpha is more than 0 and less than 1; based on DDCCP4 for the uniform velocity adjustment phase is determined.
Specifically, the determination of the position of point P4 in this embodiment determines the effect of the deceleration stage, and if the position of the point is too high relative to the set height, the deceleration may be advanced, which may affect the adjustment efficiency. If set too low, the speed will not yet decrease to 0m/min when the target height is reached, causing an overshoot. As for the exact location of point P4, the deceleration distance D may be setDCC(distance from point P5 to point P4) as a parameter, set by the commissioning personnel. DDCCThe value can be related to factors such as Z-axis acceleration, Z-axis hysteresis value, interpolation period of a numerical control system, sensitivity of a capacitance sensor and the like, and can be measuredThe trial method, which is set a little bit first, is reduced appropriately as long as overshoot does not occur until a minimum value (D) is determinedDCC) min, then pair (D)DCC) min performs a margin reservation process, i.e. at (D)DCC) Weighting appropriately on the basis of min to obtain the final DDCCIn practical application, α can be 0.8, i.e. DDCC＝(DDCC) min/0.8 is the deceleration distance, and the margin of 20 percent is reserved to ensure the stability.
Optionally, the controlling the laser cutting head to perform acceleration adjustment between the start point P1 and the start point P2 of the alignment adjustment includes: based on a speed of movement D associated with the laser cutting headIPOThe continuous derivative function with the monotone increasing interval controls the laser cutting head to perform acceleration adjustment between the initial points P1 and P2 of the alignment adjustment; dIPOAccording to UDIFAnd determining the product of a preset adjusting factor K; k is UDIFEqual to 1V, the laser cutting head moves a distance in an interpolation period.
The acceleration phases P1-P2 refer to when the distance from the bottom surface of the nozzle to the surface of the sheet is greater than the maximum value of the span range of the capacitive sensor (if the span of the capacitive sensor is 0-20mm), i.e. the feedback voltage of the capacitive sensor is always kept at the maximum value, taking up the aforementioned distance, i.e. 10V. At the moment, the initial height of the laser cutting head which is adjusted to be started is higher, and if the voltage value U corresponding to the actually set height is subtracted from the actually fed back voltage maximum valueSETAs UDIFIt is imperative to reduce the speed of adjustment, so assume U at this stageSETIs 0, at this time UDIFAt a maximum of 10V. Adjusting the falling distance of the Z axis in the first interpolation period of starting to be DIPO＝K·UDIFAssuming that the interpolation period of the CNC (computer Numerical Control) is 2ms and the value of K is 100, the time corresponding to 2ms moves by 1mm, that is, the speed suddenly increases from 0m/min to 30m/min, so that the Z-axis instantaneously generates an excessive acceleration, thereby causing an overload alarm or Z-axis vibration in the servo drive. Based on this, the embodiment employs a relationship D in the acceleration stageIPOWith monotonically increasing intervalsAnd the derivative function controls the continuous and smooth transition of the acceleration of the laser cutting head in the acceleration adjusting stage.
As an embodiment of the present embodiment, the acceleration adjustment phase is performed by sinusoidal acceleration, which is related to the movement speed D of the laser cutting headIPOThe continuously derivable function with a monotonically increasing interval of (a) is expressed as:
wherein n is the total number of cycles of the interpolation cycle in the acceleration adjustment stage, that is, the number of cycles of acceleration, and can be set according to the performance of the machine tool, and the value is 5 under normal conditions; i is the cycle number, i.e. the cycle number of the acceleration process at the current cycle.
Thus, in the nth period, i.e. when i ═ n, DIPO＝K·UDIFThe speed is increased to the maximum and the acceleration adjustment is ended, 10K.
Optionally, controlling the laser cutting head to perform deceleration adjustment from P4 includes: based on association with DIPOThe laser cutting head is controlled to perform deceleration adjustment from P4 by a continuously-derivable function with a monotonically decreasing interval.
Specifically, after entering the deceleration section from P4 to P5, smooth transition of the adjusting speed, namely smooth change of the pressure difference, is ensured. At the beginning of the phase P4-P5, i.e. the pressure difference at point P4 is considered to be maximum, the aforesaid distance, i.e. U, continues to be taken upDIF10V, and further adjust the speed DIPO＝K·UDIFFor the purpose of smooth transition, the present embodiment adopts a relationship D of 10KIPOThe continuous derivative function with the monotone decreasing interval controls the acceleration of the laser cutting head in the deceleration adjusting stage to continuously and smoothly transit. It will be appreciated that at the end of the acceleration adjustment phase, U is nowACTAnd USETAre equal.
As an implementation manner of this embodiment, the deceleration adjusting phase is performed by using a sinusoidal deceleration method, which is related to DIPOHaving monotonically decreasing intervalsThe function is represented as:
wherein, m is the total number of cycles of the interpolation cycle in the deceleration adjustment stage, that is, the number of cycles of the sinusoidal deceleration duration, and may be set according to the performance of the machine tool, and in general, m is 5; j is the cycle number indicating that the current cycle is the second cycle of the sinusoidal deceleration process.
Thus, in the mth period, i.e., when j ═ m, UACTAnd USETAnd when the adjustment speed is 0, the laser cutting head is adjusted in place, and the process of performing laser cutting on the workpiece to be cut can be executed.
Specifically, the controlling the laser cutting head to perform uniform speed adjustment between P2 and P4 includes: controlling the laser cutting head to be adjusted from P2 to a sensor sensing point P3 between P2 and P4 at a constant speed; p3 is the point where the laser cutting head moves to the point where the capacitance sensor begins to enter the range of measurement; dynamically adjusting U starting from P3SETTo make UDIFThe constant value is the maximum feedback voltage value of the capacitance sensor, and the laser cutting head is controlled to continue to be adjusted to the constant speed from P3 to P4.
With reference to fig. 5, it should be noted that, in the uniform speed adjustment stage, during the uniform speed falling of the laser cutting head along the Z axis, the maximum speed is maintained until the deceleration point P4 is reached, the laser cutting head first passes through the sensing starting point of the capacitance sensor, the area behind the sensing starting point is the sensing area of the capacitance sensor, and at this time, the capacitance sensor enters the range of the measurement range to start the feedback voltage value change. As can be seen from FIG. 5, after entering the area, as the laser cutting head descends, the distance between the bottom of the nozzle and the plate becomes closer and closer, and the feedback voltage U of the capacitance sensorACTWill also get smaller and smaller when the set height is unchanged (i.e., U)SETConstant), pressure difference UDIF＝UACT-USETAnd also becomes smaller. If no processing is performed, the falling speed starts to decrease at the point P3, which is equivalent to early deceleration, thereby affecting the adjustment efficiency. In this embodiment, the setting can be dynamically adjusted in the stages P3-P4 so as not to cause the problemTarget voltage value USETThereby making the voltage difference UDIFThe maximum feedback voltage value of the capacitance sensor is constant, so that the laser cutting head continues to keep the speed of the stages P2-P3 descending along the Z axis at a constant speed in the stages P3-P4.
Specifically, in this embodiment, the voltage difference (U) between the real-time feedback voltage of the capacitive sensor and the target voltage corresponding to the target height is usedDIF＝UACT-USET) As an actual control quantity, the real-time feedback voltage does not need to be mapped to the height between the bottom of the laser cutting head and the surface of the workpiece to be cut, and then laser cutting control is carried out, so that overshoot and plate collision can not be caused even if a curve is degraded.
Specifically, in this embodiment, after the pressure difference is obtained, the laser cutting head is subjected to follow-up control, and in the process of controlling the movement of the laser cutting head, the actual voltage value is continuously collected in real time, and when the pressure difference between the actual voltage value and the target voltage value is 0, the laser cutting head is adjusted in place. The method can control the height of the bottom of the laser cutting head from the surface of a workpiece to be cut to be constant in real time in the plate cutting process, the problems of poor cutting such as cutting width change, slag on the bottom surface of the workpiece and the like caused by the height change of a laser focus due to the fact that the surface of the workpiece to be cut is uneven can be solved, and the situations of overshoot, plate collision and the like caused by the fact that the distance of a capacitance sensor and a voltage corresponding curve are degraded can be prevented.
Optionally, according to UDIFControlling the movement of the laser cutting head includes: according to UDIFDetermining the direction of movement of the laser cutting head and based thereonUDIFAnd determining the movement speed D of the laser cutting head by multiplying a preset adjusting factor KIPO(ii) a K is UDIFWhen the voltage is equal to 1V, the distance of the laser cutting head moving in one interpolation period; controlling the laser cutting head according to the direction of movement and DIPOAnd (6) moving.
Specifically, the voltage value U corresponding to the set height is calculated in real timeSETVoltage value U corresponding to actual height acquired by capacitance sensor in real timeACTDifference value U ofDIFThe difference is multiplied by a set regulation factor K (differential pressure U)DIFDistance moved by one interpolation period when the distance is 1V), namely the adjusting distance D of the cutting head along the Z axis in one interpolation periodIPO(sign stands for direction, in microns), expressed as: dIPO＝K·UDIF. According to this formula, it can be seen that the pressure difference U is given a certain value of K (depending on the performance of the machine and the servo motor itself, too small results in too slow a regulation speed, too large results in overshoot or vibration, an appropriate value must be set by calculation, set in the machine parameters, no longer dynamically set during cutting)DIFThe regulating speed is determined by the size of the pressure difference, so that the regulating speed can be controlled by controlling the pressure difference.
According to the laser cutting control method provided by the embodiment of the invention, in the process of cutting the workpiece to be cut, the actual voltage value U fed back by the capacitance sensor based on the height of the bottom of the laser cutting head from the surface of the workpiece to be cut is obtainedACT(ii) a Calculate UACTAnd a set target voltage value USETDifference value U betweenDIF(ii) a According to UDIFControlling the laser cutting head to move, and adjusting the height of the laser cutting head from the workpiece to be cut until the height is based on the real-time acquired UACTDetermining UDIFIs zero. By implementing the method, the height of the laser cutting head from the surface of the workpiece is controlled in a follow-up manner only by taking the voltage difference between the real-time feedback voltage of the capacitance sensor and the voltage corresponding to the target height as a control quantity in the laser cutting process, the algorithm complexity is low, and the method does not need to depend on the corresponding curve of the voltage value and the distance and is not subjected to calibration curveThe influence of linear degradation, control stability and safety are high.
Second embodiment:
in order to solve the technical problems of higher algorithm complexity and lower control stability and safety caused by the following control of the height of the laser cutting head from the surface of the workpiece based on the PID algorithm and the corresponding curve of the voltage value and the distance in the related art, the present embodiment shows a laser cutting control device, and specifically refer to fig. 6, the laser cutting control device of the present embodiment includes:
an obtaining module 601, configured to obtain an actual voltage value U fed back by a capacitance sensor based on a height of a bottom of a laser cutting head from a surface of a workpiece to be cut in a process of cutting the workpiece to be cutACT；
A calculation module 602 for calculating UACTAnd a target voltage value USETDifference value U betweenDIF；USETWhen the height from the bottom of the laser cutting head to the surface of a workpiece to be cut is a preset target height, the corresponding voltage value is obtained;
a control module 603 for controlling according to UDIFControlling the laser cutting head to move, and adjusting the height of the laser cutting head from the surface of the workpiece to be cut until the height is based on the real-time acquired UACTDetermining UDIFIs zero.
Specifically, the height of the focal point in this embodiment is a vertical distance between the laser focal point and the surface of the workpiece to be cut, the set height is a vertical distance between the bottom of the laser cutting head and the surface of the workpiece to be cut when the height of the focal point is maintained, and the set height is a target height that meets the requirements of the laser cutting process. In this embodiment, the voltage difference (U) between the real-time feedback voltage of the capacitive sensor and the target voltage corresponding to the target height is usedDIF＝UACT-USET) And as an actual control quantity, performing follow-up control on the laser cutting head after acquiring the pressure difference, continuously acquiring an actual voltage value in real time in the process of controlling the movement of the laser cutting head, and adjusting the laser cutting head in place when the pressure difference between the actual voltage value and the target voltage value is 0. The method does not require thatAfter the real-time feedback voltage is mapped to the height between the bottom of the laser cutting head and the surface of a workpiece to be cut, laser cutting control is performed, the problems of poor cutting such as cutting joint width change, slag on the bottom surface of the workpiece and the like caused by the fact that the height of a laser focus is changed due to the fact that the surface of the workpiece to be cut is uneven are solved, and the situations of overshoot, plate collision and the like caused by the fact that the distance of a capacitance sensor and a voltage corresponding curve are degraded can be prevented.
In some embodiments of this embodiment, the laser cutting control device further comprises: an alignment module for obtaining the actual voltage value U fed back by the capacitance sensor based on the height of the bottom of the laser cutting head from the surface of the workpiece to be cutACTThe alignment module is used for planning the alignment adjustment process sequence into an acceleration adjustment stage, a constant speed adjustment stage and a deceleration adjustment stage when the laser cutting head is aligned when the laser cutting head is started, and determining a starting point P2 and a terminating point P4 of the constant speed adjustment stage; in the acceleration adjustment stage, the height from the bottom of the laser cutting head to the surface of the workpiece to be cut is larger than the range of the capacitance sensor; controlling the laser cutting head to perform acceleration adjustment between the starting points P1 and P2 of the alignment adjustment, controlling the laser cutting head to perform uniform speed adjustment between P2 and P4, and then controlling the laser cutting head to perform deceleration adjustment from P4 until the U is obtained in real timeACTDetermining UDIFAnd the zero value is reached, the end point P5 of the deceleration adjusting stage is reached, and the alignment adjustment is finished, so that the laser cutting head reaches the target height.
Further, in some embodiments of the present embodiment, when performing acceleration adjustment for controlling the laser cutting head between the start points P1 and P2 of the alignment adjustment, the alignment module is specifically configured to: based on a speed of movement D associated with the laser cutting headIPOThe continuous derivative function with the monotone increasing interval controls the laser cutting head to perform acceleration adjustment between the initial points P1 and P2 of the alignment adjustment; dIPOAccording to UDIFAnd determining the product of a preset adjusting factor K; k is UDIFWhen the voltage is equal to 1V, the distance of the laser cutting head moving in one interpolation period; and/or, controlling the laser cutting head to make a deceleration adjustment starting from P4 comprises: base ofIs associated with DIPOThe laser cutting head is controlled to perform deceleration adjustment from P4 by a continuously-derivable function with a monotonically decreasing interval.
Further, in some embodiments of the present embodiments, a speed of movement D associated with the laser cutting head isIPOThe continuously derivable function with a monotonically increasing interval of (a) is expressed as:
wherein n is the total number of periods of the interpolation period in the acceleration adjustment stage, and i is the period number;
is associated with DIPOThe continuously derivable function with a monotonically decreasing interval of (a) is expressed as:
wherein m is the total number of the interpolation periods in the deceleration adjusting stage, and j is the period number.
Further, in some embodiments of the present embodiment, when performing control of the laser cutting head to perform uniform adjustment between P2 and P4, the alignment module is specifically configured to control the laser cutting head to perform uniform adjustment from P2 to a sensor sensing point P3 between P2 and P4; p3 is the point where the laser cutting head moves to the point where the capacitance sensor begins to enter the range of measurement; dynamically adjusting U starting from P3SETTo make UDIFThe constant value is the maximum feedback voltage value of the capacitance sensor, and the laser cutting head is controlled to continue to be adjusted to the constant speed from P3 to P4. .
Further, in some embodiments of the present embodiment, when the step P4 of determining the uniform speed adjustment stage is executed, the alignment module is specifically configured to determine a minimum value (D) of the deceleration distance corresponding to the deceleration adjustment stageDCC) min; to (D)DCC) min is subjected to allowance reservation processing to obtain a target deceleration distance DDCCThe margin reservation processing formula can be expressed as: dDCC＝(DDCC) min/alpha, alpha is more than 0 and less than 1; based on DDCCP4 for the uniform velocity adjustment phase is determined.
In some embodiments of this embodiment, the performing is according to UDIFControl module 603 is specifically configured to control laser cutting head movement according to UDIFDetermining the movement direction of the laser cutting head and according to UDIFAnd determining the movement speed D of the laser cutting head by multiplying a preset adjusting factor KIPO(ii) a K is UDIFWhen the voltage is equal to 1V, the distance of the laser cutting head moving in one interpolation period; controlling the laser cutting head according to the direction of movement and DIPOAnd (6) moving.
It should be noted that, the laser cutting control method in the foregoing embodiments can be implemented based on the laser cutting control device provided in this embodiment, and it can be clearly understood by those skilled in the art that, for convenience and simplicity of description, the specific working process of the laser cutting control device described in this embodiment may refer to the corresponding process in the foregoing method embodiments, and is not described herein again.
By adopting the laser cutting control device provided by the embodiment, in the process of cutting the workpiece to be cut, the actual voltage value U fed back by the capacitance sensor based on the height of the bottom of the laser cutting head from the surface of the workpiece to be cut is obtainedACT(ii) a Calculate UACTAnd a set target voltage value USETDifference value U betweenDIF(ii) a According to UDIFControlling the laser cutting head to move, and adjusting the height of the laser cutting head from the surface of the workpiece to be cut until the height is based on the real-time acquired UACTDetermining UDIFIs zero. By implementing the method, the height of the laser cutting head from the surface of the workpiece is controlled in a follow-up manner only by taking the voltage difference between the real-time feedback voltage of the capacitance sensor and the voltage corresponding to the target height as a control quantity in the laser cutting process, the algorithm complexity is low, the method does not need to depend on the corresponding curve of the voltage value and the distance and is not influenced by the degradation of a calibration curve, and the control stability and the safety are high.
The third embodiment:
the present embodiment provides an electronic apparatus, as shown in fig. 7, which includes a processor 701, a memory 702, and a communication bus 703, wherein: the communication bus 703 is used for realizing connection communication between the processor 701 and the memory 702; the processor 701 is configured to execute one or more computer programs stored in the memory 702 to implement at least one step of the laser cutting control method in the first embodiment.
The present embodiments also provide a computer-readable storage medium including volatile or non-volatile, removable or non-removable media implemented in any method or technology for storage of information such as computer-readable instructions, data structures, computer program modules or other data. Computer-readable storage media include, but are not limited to, RAM (Random Access Memory), ROM (Read-Only Memory), EEPROM (Electrically Erasable Programmable Read-Only Memory), flash Memory or other Memory technology, CD-ROM (Compact disk Read-Only Memory), Digital Versatile Disks (DVD) or other optical disk storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other medium which can be used to store the desired information and which can be accessed by a computer.
The computer-readable storage medium in this embodiment may be used for storing one or more computer programs, and the stored one or more computer programs may be executed by a processor to implement at least one step of the method in the first embodiment.
The present embodiment also provides a computer program, which can be distributed on a computer readable medium and executed by a computing device to implement at least one step of the method in the first embodiment; and in some cases at least one of the steps shown or described may be performed in an order different than that described in the embodiments above.
The present embodiments also provide a computer program product comprising a computer readable means on which a computer program as shown above is stored. The computer readable means in this embodiment may include a computer readable storage medium as shown above.
It will be apparent to those skilled in the art that all or some of the steps of the methods, systems, functional modules/units in the devices disclosed above may be implemented as software (which may be implemented in computer program code executable by a computing device), firmware, hardware, and suitable combinations thereof. In a hardware implementation, the division between functional modules/units mentioned in the above description does not necessarily correspond to the division of physical components; for example, one physical component may have multiple functions, or one function or step may be performed by several physical components in cooperation. Some or all of the physical components may be implemented as software executed by a processor, such as a central processing unit, digital signal processor, or microprocessor, or as hardware, or as an integrated circuit, such as an application specific integrated circuit.
In addition, communication media typically embodies computer readable instructions, data structures, computer program modules or other data in a modulated data signal such as a carrier wave or other transport mechanism and includes any information delivery media as known to one of ordinary skill in the art. Thus, the present invention is not limited to any specific combination of hardware and software.
The foregoing is a more detailed description of embodiments of the present invention, and the present invention is not to be considered limited to such descriptions. For those skilled in the art to which the invention pertains, several simple deductions or substitutions can be made without departing from the spirit of the invention, and all shall be considered as belonging to the protection scope of the invention.
Claims (8)
1. A laser cutting control method, comprising:
in the process of cutting a workpiece to be cut, acquiring an actual voltage value U fed back by a capacitance sensor based on the height of the bottom of a laser cutting head from the surface of the workpiece to be cutACT；
Calculating the UACTAnd the targetVoltage value USETDifference value U betweenDIF(ii) a The U isSETWhen the height from the bottom of the laser cutting head to the surface of the workpiece to be cut is a preset target height, the corresponding voltage value is obtained;
according to the UDIFControlling the laser cutting head to move, and adjusting the height of the laser cutting head from the surface of the workpiece to be cut until the U is acquired in real timeACTDetermining the UDIFIs zero;
acquiring an actual voltage value U fed back by a capacitance sensor based on the height of the bottom of the laser cutting head from the surface of the workpiece to be cutACTBefore, still include:
when the laser cutting is started to align the laser cutting head, the alignment adjustment process is planned to be an acceleration adjustment stage, a constant speed adjustment stage and a deceleration adjustment stage, and a starting point P2 and an end point P4 of the constant speed adjustment stage are determined; in the acceleration adjustment stage, the height from the bottom of the laser cutting head to the surface of the workpiece to be cut is larger than the range of the capacitance sensor;
controlling the laser cutting head to perform acceleration adjustment between a starting point P1 of alignment adjustment and the P2, controlling the laser cutting head to perform uniform speed adjustment between the P2 and the P4, and then controlling the laser cutting head to perform deceleration adjustment from the P4 until the U is obtained in real timeACTDetermining the UDIFWhen the target height is zero, the target height reaches a termination point P5 of the deceleration adjusting stage, and the alignment adjustment is finished, so that the laser cutting head reaches the target height;
and the controlling the laser cutting head to perform uniform speed adjustment between the P2 and the P4 comprises the following steps:
controlling the laser cutting head to adjust from the P2 to a sensor sensing point P3 between the P2 and the P4 at a constant speed; the P3 is the point at which the laser cutting head moves to the point at which the capacitive sensor begins to enter the span range;
dynamically adjusting the U starting from the P3SETSo that the U isDIFIs constant atAnd controlling the laser cutting head to continuously adjust from the P3 to the P4 at a constant speed according to the maximum feedback voltage value of the capacitance sensor.
2. The laser cutting control method of claim 1, wherein the U is based on the UDIFControlling the laser cutting head to move comprises:
according to the UDIFDetermining the movement direction of the laser cutting head and according to the UDIFAnd determining the movement speed D of the laser cutting head by multiplying a preset adjusting factor KIPO(ii) a K is UDIFWhen the value is equal to 1V, the distance of the laser cutting head moving in one interpolation period;
controlling the laser cutting head according to the movement direction and DIPOAnd (6) moving.
3. The laser cutting control method of claim 1, wherein the controlling the laser cutting head to perform acceleration adjustment between a starting point P1 of the alignment adjustment and the P2 comprises:
based on a speed of movement D associated with the laser cutting headIPOThe laser cutting head is controlled to perform acceleration adjustment between a starting point P1 of alignment adjustment and the P2; said DIPOAccording to the UDIFAnd determining the product of a preset adjusting factor K; k is UDIFWhen the value is equal to 1V, the distance of the laser cutting head moving in one interpolation period;
and/or the controlling the laser cutting head to perform deceleration adjustment from the P4 comprises:
based on association with said DIPOThe laser cutting head is controlled to perform deceleration adjustment from the P4 by a continuous derivative function with a monotonically decreasing interval.
4. Laser cutting control method according to claim 3, characterized in that said speed D related to the movement of the laser cutting headIPOThe continuously derivable function with a monotonically increasing interval of (a) is expressed as:
wherein n is the total number of periods of the interpolation period in the acceleration adjustment stage, and i is a period number;
said association with said DIPOThe continuously derivable function with a monotonically decreasing interval of (a) is expressed as:
wherein, m is the total number of periods of the interpolation period in the deceleration adjusting stage, and j is a period number.
5. The laser cutting control method according to claim 1, wherein the determining P4 of the constant speed adjustment phase comprises:
determining the minimum value (D) of the deceleration distance corresponding to the deceleration adjustment phaseDCC)min；
To the (D)DCC) min is subjected to allowance reservation processing to obtain a target deceleration distance DDCCThe margin reservation processing formula is expressed as: dDCC＝(DDCC) min/a, wherein a is more than 0 and less than 1;
based on the DDCCAnd determining P4 of the uniform speed adjusting stage.
6. A laser cutting control apparatus, comprising:
an acquisition module used for acquiring an actual voltage value U fed back by the capacitance sensor based on the height of the bottom of the laser cutting head from the surface of the workpiece to be cut in the process of cutting the workpiece to be cutACT；
A calculation module for calculating the UACTAnd a target voltage value USETDifference value U betweenDIF(ii) a The U isSETWhen the height from the bottom of the laser cutting head to the surface of the workpiece to be cut is a preset target height, the corresponding voltage value is obtained;
a control module for controlling the current according to the UDIFControlling the laser cutting head to move, and adjusting the height of the laser cutting head from the surface of the workpiece to be cut until the U is acquired in real timeACTDetermining the UDIFIs zero;
the alignment module is used for acquiring an actual voltage value U fed back by the capacitance sensor based on the height of the bottom of the laser cutting head from the surface of the workpiece to be cutACTBefore, when laser cutting is started to align the laser cutting head, the alignment adjustment process is planned to be an acceleration adjustment stage, a constant speed adjustment stage and a deceleration adjustment stage, and a starting point P2 and a terminating point P4 of the constant speed adjustment stage are determined; in the acceleration adjustment stage, the height from the bottom of the laser cutting head to the surface of the workpiece to be cut is larger than the range of the capacitance sensor; controlling the laser cutting head to perform acceleration adjustment between a starting point P1 of alignment adjustment and the P2, controlling the laser cutting head to perform uniform speed adjustment between the P2 and the P4, and then controlling the laser cutting head to perform deceleration adjustment from the P4 until the U is obtained in real timeACTDetermining the UDIFWhen the target height is zero, the target height reaches a termination point P5 of the deceleration adjusting stage, and the alignment adjustment is finished, so that the laser cutting head reaches the target height;
when the alignment module performs the uniform speed adjustment of the laser cutting head between P2 and P4, the alignment module is specifically configured to: controlling the laser cutting head to adjust from the P2 to a sensor sensing point P3 between the P2 and the P4 at a constant speed; the P3 is the point at which the laser cutting head moves to the point at which the capacitive sensor begins to enter the span range; dynamically adjusting the U starting from the P3SETSo that the U isDIFThe value of the maximum feedback voltage of the capacitance sensor is constant, and the laser cutting head is controlled to continue to be leveled from the P3The speed is adjusted to the P4.
7. An electronic device, comprising: a processor, a memory, and a communication bus;
the communication bus is used for realizing connection communication between the processor and the memory;
the processor is configured to execute one or more programs stored in the memory to implement the steps of the laser cutting control method according to any one of claims 1 to 5.
8. A computer-readable storage medium storing one or more programs, the one or more programs being executable by one or more processors to implement the steps of the laser cutting control method according to any one of claims 1 to 5.
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| CN111745311B (en) * | 2020-06-30 | 2022-03-25 | 大族激光科技产业集团股份有限公司 | Laser perforation method, multi-stage perforation method and continuous perforation method |
| CN112212787B (en) * | 2020-10-13 | 2022-03-25 | 上海柏楚数控科技有限公司 | Method, device and equipment for detecting focus offset of laser equipment and storage medium |
| CN115916451B (en) * | 2020-10-16 | 2024-02-20 | 百超激光有限公司 | Method, control unit and laser cutting system for calculating spatially and temporally resolved, combined setpoint data sets |
| CN112643228A (en) * | 2021-01-21 | 2021-04-13 | 上海维宏电子科技股份有限公司 | Method, system, device, processor and storage medium for realizing capacitance compensation control on cutting head temperature drift in laser cutting system |
| CN113231735B (en) * | 2021-04-15 | 2023-06-23 | 大族激光科技产业集团股份有限公司 | Cutting head obstacle avoidance method, device, computer equipment and medium |
| CN113909683B (en) * | 2021-10-13 | 2022-06-14 | 华中科技大学 | Three-laser-head collaborative cutting blanking path planning method and system with delta-shaped layout |
| CN113857695A (en) * | 2021-11-08 | 2021-12-31 | 武汉威士登智能控制技术有限公司 | CNC _ Z-axis laser cutting follow-up control algorithm |
| CN113977332A (en) * | 2021-12-02 | 2022-01-28 | 上海维宏智能技术有限公司 | Method, device, processor and storage medium for realizing obstacle detection and active obstacle avoidance control based on capacitive sensor |
| CN114535827A (en) * | 2022-02-16 | 2022-05-27 | 深圳市小步数控有限公司 | Laser head motion control method, motion control system, and laser processing machine |
| CN114535844B (en) * | 2022-03-31 | 2024-03-19 | 华工法利莱切焊系统工程有限公司 | Laser cutting head working distance monitoring system and method |
| CN117655563A (en) * | 2024-01-31 | 2024-03-08 | 成都沃特塞恩电子技术有限公司 | Laser cutting path planning method and device, electronic equipment and storage medium |
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| EP2480859B1 (en) * | 2009-09-22 | 2018-07-18 | Laser Mechanisms, Inc. | Fast response capacitive sensing system featuring steep slope filter discrimination circuit |
| CN202591845U (en) * | 2012-05-09 | 2012-12-12 | 武汉奥森迪科智能电控科技有限公司 | Automatic control system for nozzles of laser cutting heads |
| JP5897233B1 (en) * | 2015-03-13 | 2016-03-30 | 三菱電機株式会社 | Laser processing apparatus, calibration data generation method and program |
| CN105446366B (en) * | 2015-12-29 | 2018-03-06 | 武汉嘉铭激光有限公司 | A kind of position control system and its control method based on capacitance type sensor |
| CN105945420A (en) * | 2016-06-28 | 2016-09-21 | 善测（天津）科技有限公司 | Active shielding type capacitor height-following measuring device |
| CN108422079B (en) * | 2016-11-08 | 2020-04-10 | 中国人民解放军空军工程大学航空机务士官学校 | Control device of laser cutting system |
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