CN111774915A - Machine tool positioning method and device and machine tool equipment - Google Patents
Machine tool positioning method and device and machine tool equipment Download PDFInfo
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- CN111774915A CN111774915A CN202010653968.XA CN202010653968A CN111774915A CN 111774915 A CN111774915 A CN 111774915A CN 202010653968 A CN202010653968 A CN 202010653968A CN 111774915 A CN111774915 A CN 111774915A
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23Q—DETAILS, COMPONENTS, OR ACCESSORIES FOR MACHINE TOOLS, e.g. ARRANGEMENTS FOR COPYING OR CONTROLLING; MACHINE TOOLS IN GENERAL CHARACTERISED BY THE CONSTRUCTION OF PARTICULAR DETAILS OR COMPONENTS; COMBINATIONS OR ASSOCIATIONS OF METAL-WORKING MACHINES, NOT DIRECTED TO A PARTICULAR RESULT
- B23Q5/00—Driving or feeding mechanisms; Control arrangements therefor
- B23Q5/22—Feeding members carrying tools or work
- B23Q5/34—Feeding other members supporting tools or work, e.g. saddles, tool-slides, through mechanical transmission
- B23Q5/38—Feeding other members supporting tools or work, e.g. saddles, tool-slides, through mechanical transmission feeding continuously
- B23Q5/40—Feeding other members supporting tools or work, e.g. saddles, tool-slides, through mechanical transmission feeding continuously by feed shaft, e.g. lead screw
Abstract
The invention discloses a machine tool positioning method and device and machine tool equipment. Wherein, the method comprises the following steps: acquiring current position data of a feed shaft of a target machine tool and a last detection filter value, wherein the last detection filter value is a filter basic value obtained in a last interval duration; determining an error accuracy in acquiring current position data of the feed shaft; based on the error precision and the detection filter value, carrying out filter processing on the current position data to obtain coordinate data of the feed shaft; based on the coordinate data of the feed axis, the current coordinates of the feed axis of the target machine tool are located. The invention solves the technical problem that the coordinate positioning precision of the machine tool feed shaft in the related technology is easy to suffer from accumulated errors of devices, so that unqualified products are produced.
Description
Technical Field
The invention relates to the technical field of machine tool control, in particular to a positioning method and device of a machine tool and machine tool equipment.
Background
In the related art, the coordinate positioning accuracy of the machine tool feed shaft is mainly related to the accuracy of the screw rod, the accuracy of the feed motor encoder, the minimum accuracy error of external measuring equipment such as a grating ruler and the like, and in the daily production process, the measurement data of a measuring device with smaller error accuracy is generally taken as the reference of motion control. Although the precision of the precision measurement device is high and the error is relatively small, the error is always present, and when the machine tool equipment performs a long-time continuous motion control operation (starting from a zero point and then does not return to zero), the errors are accumulated continuously, so that a large accumulated error is finally reflected on a later-stage workpiece, procedure or product, and an unqualified product is produced.
In view of the above problems, no effective solution has been proposed.
Disclosure of Invention
The embodiment of the invention provides a positioning method and device of a machine tool and machine tool equipment, which at least solve the technical problem that unqualified products are caused by accumulated errors of devices easily caused by the coordinate positioning precision of a machine tool feed shaft in related technologies.
According to an aspect of an embodiment of the present invention, there is provided a positioning method of a machine tool, including: acquiring current position data of a feed shaft of a target machine tool and a last detection filter value, wherein the last detection filter value is a filter basic value obtained in a last interval duration; determining an error accuracy in acquiring the current position data of the feed shaft; based on the error precision and the detection filtering value, filtering the current position data to obtain coordinate data of the feed shaft; and positioning the current coordinates of the feed shaft of the target machine tool based on the coordinate data of the feed shaft.
Optionally, the step of obtaining the current position data of the feed axis of the target machine tool and the last detection filter value includes: acquiring the position coordinate of the feed shaft of the target machine tool by adopting position detection equipment to obtain the current position data; and extracting the filtering data when the current position data of the feed shaft is obtained in the last interval duration to obtain the last detection filtering value.
Optionally, the step of determining the accuracy of the error in obtaining the current position data of the feed shaft comprises: determining the pitch and deviation parameters of each turn of a ball screw of a feed shaft on the target machine tool; and calculating the error precision of the feed shaft when the feed shaft runs to reach the preset distance length based on the screw pitch and the deviation parameter.
Optionally, the step of performing filtering processing on the current position data to obtain coordinate data of the feed axis includes: predicting the running state value of the feed shaft of the target machine tool at the current moment based on the last detection filter value; determining the transfer relationship of a plurality of operation influence factors at the current moment; determining position observation data of the feeding shaft based on the running state value of the current moment and the coordinate data; calculating filter gain data based on the position observation data and the transfer relationship; calculating an estimated value of the running state of the feed shaft at the current moment and a covariance matrix based on the filter gain data and the position observation data; and determining the coordinate data of the feed shaft based on the covariance matrix and the estimated value of the running state at the current moment.
Optionally, the step of predicting the running state value of the feed axis of the target machine tool at the current time based on the last detected filtered value includes: acquiring a state transition matrix, a control matrix and a control vector of the target machine tool during operation, wherein the state transition matrix is used for indicating movement data of a feed shaft of the target machine tool in a preset distance length range, the control matrix is used for indicating control data for controlling the operation of the feed shaft of the target machine tool, and the control vector is used for indicating a vector parameter for controlling the movement direction and the movement coordinate of the feed shaft; determining process noise of the target machine tool while running based on the error accuracy; and predicting the running state value of the feed shaft of the target machine tool at the current moment based on the state transition matrix, the last detection filtering value, the control matrix, the control vector and the process noise.
Optionally, the step of determining a transfer relationship of the plurality of operational influencing factors at the current time includes: acquiring a covariance matrix of the last time and a covariance of the process noise; and determining the transfer relationship of a plurality of operation influence factors at the current moment based on the state transition matrix of the target machine tool in operation, the previous covariance matrix and the covariance of the process noise.
Optionally, the step of obtaining the covariance matrix of the last time and the covariance of the process noise includes: calculating a difference value between the last position observation value and the initial position prediction value to obtain a position difference value; taking the square operation result of the position difference value as the covariance of the last time; and constructing a previous covariance matrix based on the previous covariance and the covariance of the initial moment.
According to another aspect of the embodiments of the present invention, there is also provided a positioning apparatus of a machine tool, including: the device comprises an acquisition unit, a processing unit and a control unit, wherein the acquisition unit is used for acquiring current position data of a feed shaft of a target machine tool and a last detection filter value, and the last detection filter value refers to a filter basic value obtained in a last interval duration; a determination unit configured to determine an error accuracy in acquiring the current position data of the feed shaft; the filtering unit is used for carrying out filtering processing on the current position data based on the error precision and the detection filtering value to obtain coordinate data of the feed shaft; and the positioning unit is used for positioning the current coordinate of the feed shaft of the target machine tool based on the coordinate data of the feed shaft.
Optionally, the obtaining unit includes: the acquisition module is used for acquiring the position coordinates of the feed shaft of the target machine tool by adopting position detection equipment to obtain the current position data; and the extraction module is used for extracting the filtering data when the current position data of the feed shaft is acquired within the last interval duration to obtain the last detection filtering value.
Optionally, the determining unit includes: the first determination module is used for determining the thread pitch and deviation parameters of each turn of a ball screw of a feeding shaft on the target machine tool; and the first calculation module is used for calculating the error precision of the feed shaft when the feed shaft runs to reach the preset distance length based on the thread pitch and the deviation parameter.
Optionally, the filtering unit includes: the first prediction module is used for predicting the running state value of the feed shaft of the target machine tool at the current moment based on the last detection filter value; the second determining module is used for determining the transfer relationship of the multiple operation influence factors at the current moment; the third determination module is used for determining position observation data of the feeding shaft based on the running state value of the current moment and the coordinate data; a second calculation module for calculating filter gain data based on the position observation data and the transfer relationship; the third calculation module is used for calculating the running state estimated value and the covariance matrix of the feed shaft at the current moment based on the filter gain data and the position observation data; and the fourth determination module is used for determining the coordinate data of the feed shaft based on the covariance matrix and the running state estimated value at the current moment.
Optionally, the first prediction module comprises: the first obtaining submodule is used for obtaining a state transition matrix, a control matrix and a control vector of the target machine tool during operation, wherein the state transition matrix is used for indicating movement data of a feed shaft of the target machine tool in a preset distance length range, the control matrix is used for indicating control data for controlling the operation of the feed shaft of the target machine tool, and the control vector is used for indicating a vector parameter for controlling the movement direction and the movement coordinate of the feed shaft; a first determination submodule for determining process noise of the target machine tool when running based on the error accuracy; and the predicting sub-module is used for predicting the running state value of the feed shaft of the target machine tool at the current moment based on the state transition matrix, the last detection filtering value, the control matrix, the control vector and the process noise.
Optionally, the second determining module includes: the second obtaining submodule is used for obtaining the covariance matrix of the last time and the covariance of the process noise; and the second determining submodule is used for determining the transfer relationship of a plurality of operation influence factors at the current moment based on the state transition matrix of the target machine tool in operation, the previous covariance matrix and the covariance of the process noise.
Optionally, the second obtaining sub-module is configured to include: the calculation submodule is used for calculating the difference value between the last position observation value and the initial position prediction value to obtain a position difference value; a third determining submodule, configured to use a result of a square operation of the position difference as the previous covariance; and the construction submodule is used for constructing a covariance matrix of the last time based on the covariance of the last time and the covariance of the initial moment.
According to another aspect of the embodiments of the present invention, there is also provided a machine tool apparatus including: a processor; and a memory for storing executable instructions of the processor; wherein the processor is configured to perform the method of positioning a machine tool of any of the above via execution of the executable instructions.
According to another aspect of the embodiments of the present invention, there is also provided a computer-readable storage medium, which includes a stored computer program, wherein when the computer program runs, the apparatus on which the computer-readable storage medium is located is controlled to execute the positioning method of the machine tool described in any one of the above.
In the embodiment of the invention, the current position data and the last detection filter value of the feed shaft of the target machine tool are obtained, then the error precision when the current position data of the feed shaft is obtained is determined, the current position data is filtered based on the error precision and the detection filter value to obtain the coordinate data of the feed shaft, and finally the current coordinate of the feed shaft of the target machine tool is positioned based on the coordinate data of the feed shaft. In the embodiment, the detected position data can be subjected to filtering processing in real time, and in combination with the last detection filtering value, more accurate position data closer to an actual state can be further obtained on the error precision of the detection equipment, the current coordinate of the feed shaft is determined by using the filtered coordinate data, the accumulated error of long-time continuous work of the feed shaft is reduced, and the control precision of the feed shaft is further improved, so that the technical problem that unqualified products are caused due to the fact that the accumulated error of components is easily received by the coordinate positioning precision of the machine tool feed shaft in the related technology is solved.
Drawings
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the invention without limiting the invention. In the drawings:
FIG. 1 is a flow chart of an alternative method of positioning a machine tool according to an embodiment of the invention;
FIG. 2 is a schematic diagram of an alternative filtering process for location data in accordance with an embodiment of the present invention;
FIG. 3 is a schematic view of an alternative positioning apparatus for a machine tool according to an embodiment of the present invention.
Detailed Description
In order to make the technical solutions of the present invention better understood, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious 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.
It should be noted that the terms "first," "second," and the like in the description and claims of the present invention and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the invention described herein are capable of operation in sequences other than those illustrated or described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.
The following embodiments of the present invention may be applied to various machine tool devices of types including, but not limited to: digit control machine tool, automatic machine tool. When the positioning coordinate of the feeding shaft of the numerical control machine tool is determined, the current position data is obtained by utilizing a plurality of external measuring devices (such as a screw rod, a feeding motor encoder and a grating ruler), and the current position data is filtered based on the last basic filtering value, so that the accumulated error of long-time continuous work of the feeding shaft can be reduced, the unnecessary zero returning times are reduced to reduce the processing time, the working efficiency is improved, and the control precision of the feeding shaft is improved. The present invention will be described in detail with reference to examples.
Example one
In accordance with an embodiment of the present invention, there is provided an embodiment of a method for positioning a machine tool, it being noted that the steps illustrated in the flowchart of the drawings may be performed in a computer system, such as a set of computer-executable instructions, and that while a logical order is illustrated in the flowchart, in some cases the steps illustrated or described may be performed in an order different than presented herein.
Fig. 1 is a flow chart of an alternative method of positioning a machine tool according to an embodiment of the invention, as shown in fig. 1, the method comprising the steps of:
step S102, obtaining current position data of a feed shaft of a target machine tool and a last detection filter value, wherein the last detection filter value is a filter basic value obtained in a last interval duration;
step S104, determining the error precision when the current position data of the feed shaft is obtained;
step S106, filtering the current position data based on the error precision and the detection filtering value to obtain the coordinate data of the feed shaft;
and step S108, positioning the current coordinate of the feed shaft of the target machine tool based on the coordinate data of the feed shaft.
Through the steps, the current position data and the last detection filter value of the feed shaft of the target machine tool can be obtained, then the error precision when the current position data of the feed shaft is obtained is determined, the current position data is subjected to filtering processing based on the error precision and the detection filter value to obtain the coordinate data of the feed shaft, and finally the current coordinate of the feed shaft of the target machine tool is positioned based on the coordinate data of the feed shaft. In the embodiment, the detected position data can be subjected to filtering processing in real time, and in combination with the last detection filtering value, more accurate position data closer to an actual state can be further obtained on the error precision of the detection equipment, the current coordinate of the feed shaft is determined by using the filtered coordinate data, the accumulated error of long-time continuous work of the feed shaft is reduced, and the control precision of the feed shaft is further improved, so that the technical problem that unqualified products are caused due to the fact that the accumulated error of components is easily received by the coordinate positioning precision of the machine tool feed shaft in the related technology is solved.
The following describes embodiments of the present invention with reference to the above steps.
Before acquiring the current position data, the positioning method further comprises: detecting whether a target machine tool is powered on; if the target machine tool is determined to be electrified, controlling a servo motor of the feed shaft to prepare for work; setting an initial value of covariance, an initial value of measurement noise and an initial value of process noise; and obtaining first current position data by using position detection equipment, and taking the current position data as a filtering initial value.
And S102, acquiring current position data of a feed shaft of the target machine tool and a last detection filter value, wherein the last detection filter value is a filter basic value obtained in a last interval duration.
Optionally, the step of obtaining the current position data of the feed axis of the target machine tool and the last detection filter value includes: acquiring the position coordinate of a feed shaft of a target machine tool by adopting position detection equipment to obtain current position data; and extracting the filtering data when the current position data of the feed shaft is obtained in the last interval duration to obtain the last detection filtering value.
One or more position sensing devices for a feed axis operating on a target machine tool apparatus, including but not limited to: the embodiment of the invention relates to a grating ruler and an encoder, wherein the grating ruler is used as position detection equipment, and the grating ruler detects that data has self errors and precision errors. The position detection equipment collects the position coordinates of the feed shaft of the target machine tool once every time the servo motor rotates for one circle.
In step S104, the error accuracy in acquiring the current position data of the feed shaft is determined.
Alternatively, the step of determining the accuracy of the error in acquiring the current position data of the feed shaft includes: determining the pitch and deviation parameters of each turn of a ball screw of a feed shaft on a target machine tool; and calculating the error precision of the feed shaft when the feed shaft runs to reach the preset distance length based on the screw pitch and the deviation parameter.
By inquiring the pitch of a ball screw on a machine tool (for example, arranged on an X feed shaft of the machine tool) and the deviation parameter of each turn of the screw, the error precision is further obtained, taking a GA-Z4060 three-shaft machining center X feed shaft as an example, the pitch of the X feed shaft ball screw on the machine tool is 16mm through inquiry, and the deviation of the screw in one turn is +/-0.1 um. Namely, the error precision of running the preset distance with the length of 1 meter is as follows: 1000/16 (± 0.1) ± 6.25um, the error accuracy can be regarded as the inherent noise of the ball screw, which is a normal distribution following a mean value (μ) of 0 in the pitch unit.
And S106, filtering the current position data based on the error precision and the detection filtering value to obtain the coordinate data of the feed shaft.
In the embodiment of the present invention, the step of performing filtering processing on the current position data to obtain the coordinate data of the feed axis includes: predicting the running state value of the feed shaft of the target machine tool at the current moment based on the last detection filter value; determining the transfer relationship of a plurality of operation influence factors at the current moment; determining position observation data of the feeding shaft based on the running state value and the coordinate data at the current moment; calculating filter gain data based on the position observation data and the transfer relationship; calculating an estimated value of the running state of the feed shaft at the current moment and a covariance matrix based on the filter gain data and the position observation data; and determining the coordinate data of the feed shaft based on the covariance matrix and the estimated value of the running state at the current moment.
The filtering algorithm used in the embodiment of the invention can be Kalman filtering, and the current position data is filtered through the Kalman filtering algorithm.
When the Kalman filtering algorithm is used, the operation state value at the current moment can be predicted according to the last filtering value. Optionally, the step of predicting the running state value of the feed axis of the target machine tool at the current time based on the last detection filter value includes: acquiring a state transition matrix, a control matrix and a control vector of a target machine tool during operation, wherein the state transition matrix is used for indicating movement data of a feed shaft of the target machine tool in a preset distance length range, the control matrix is used for indicating control data for controlling the feed shaft of the target machine tool in operation, and the control vector is used for indicating vector parameters for controlling the movement direction and the movement coordinate of the feed shaft; determining process noise of the target machine tool during operation based on the error precision; and predicting the running state value of the feed shaft of the target machine tool at the current moment based on the state transition matrix, the last detection filtering value, the control matrix, the control vector and the process noise.
Optionally, the following first formula is adopted to predict the operation state value at the current time, where the first formula is:
Alternatively, the step of determining the transfer relationship of the plurality of operation affecting factors at the current time includes: acquiring the covariance matrix of the last time and the covariance of process noise; and determining the transfer relationship of a plurality of operation influence factors at the current moment based on the state transition matrix of the target machine tool in operation, the previous covariance matrix and the covariance of the process noise.
Determining the transmission relationship of the plurality of operation influence factors at the previous moment at the current moment through a second formula:
In the embodiment of the present invention, the step of obtaining the covariance matrix of the last time and the covariance of the process noise includes: calculating a difference value between the last position observation value and the initial position prediction value to obtain a position difference value; taking the square operation result of the position difference as the covariance of the last time; and constructing a covariance matrix of the last time based on the covariance of the last time and the covariance of the initial moment.
The covariance at the initial time is equal to the square of the difference between the initial observed value (observed value at the initial time) minus the initial predicted value (e.g., 0), and P _ (1) ═ W (1)) > 2, where P _ (1) is the covariance at the initial time, V (1) is the initial observed value, and W (1) is the initial predicted value.
Calculating position observation data, which may be observation data of a machine tool sensor, by a third formula:
Calculating a filter gain value by a fourth formula:
Calculating a filter gain value by a fifth formula as follows:
Obtaining a covariance matrix at the current moment by a sixth formula, wherein the sixth formula is as follows:
In the embodiment of the invention, after the motor rotates for one circle, coordinate data acquired by current position data and last filtering value data can be read and filtered, and after filtering, a filtering gain value and a covariance matrix can be updated, wherein the covariance matrix is prepared for next filtering; and after updating, replacing the current position data of the current moment with the filter value of the current moment, and inputting the filter value of the current moment into the numerical control system to obtain the positioning position data close to the ideal real value.
Fig. 2 is a schematic diagram of an optional filtering process for position data according to an embodiment of the present invention, and as shown in fig. 2, the filtering process includes: 11. the grating ruler reads position data once when the servo motor rotates for one circle; 12. performing Kalman filtering on the read position data, and updating the covariance, the filtering gain value and the detection filtering value; 13. taking the position data of the first grating ruler as an initial filtering value of the filter; 14. determining an error value of the ideal predicted value; 15. and comparing data results based on the error value of the ideal predicted value, the updated covariance, the filter gain value and the detection filter value by combining the read position data.
Through the implementation mode, the position data of the feeding shaft can be read through the grating ruler (or the position error data can be directly read), the filtering processing is carried out on the position data, the covariance, the filtering gain value and the detection filtering value are updated, and finally a data result can be obtained, wherein the data result is the positioning coordinate of the feeding shaft, and the positioning mode of the feeding shaft is improved.
The covariance matrix is obtained in a detailed manner as follows.
The method comprises the following steps of firstly, setting a plurality of initial data, including: the method comprises the steps of setting the rotation direction of a motor, process noise, an initial value of observation noise, a state transition matrix, an observation matrix, an initial observation value and covariance of initial time, wherein the observation noise can be set to be normal distribution with the obedient mean value of 0 and the variance of (0.8/3)2, and the process noise is normal distribution with the mean value of 0 and the variance of 0 (the error of an ideal predicted value is zero). Then the process noise covariance is set to Q ═ 0; the observation covariance is set to be R ═ (0.8/3)2, and the state transition matrix and the observation matrix are set to be F ═ 1 and H ═ 1, respectively; setting an initial Kalman filtering value as an initial observation value; the covariance at the initial time is set to be the square of the difference between the initial observed value and the initial predicted value.
Step two, predicting a state value at the moment i: x (i) ═ X (i-1) +16000+ W (i-1)
Thirdly, adding an observed value error to an observed value at the moment i: z (i) ═ X (i) + v (i)
Fourthly, determining the covariance of the initial moment, and directly substituting for solving a gain value:
K(i)＝P_(i-1)*H'/(H*P_(i-1)*H'+R)。
from the second filtering, the covariance at the previous moment is calculated as P-:
P_(i-1)＝F*P_(i-1)*F'+Q
and (3) gain calculation: k (i) · (P _ (i-1) × H '/(H × P _ (i-1) × H' + R)).
Fifthly, increasing 16000um for a predicted value, an observed value and an optimal state estimation value every time the motor rotates for one circle;
Xkf(i-1)＝Xkf(i-1)+16000
the sixth step, presume the optimum state estimated value of the present moment with the optimum state estimated value of the last moment;
Xkf(i)＝Xkf(i-1)+K(i)*((Z(i)-H*Xkf(i-1)))；
and seventhly, updating the covariance matrix: p (i) ═ (1-k (i) × H) _ (i-1).
By the implementation mode, the optimal state estimation value and the covariance matrix at the current moment can be obtained, and the filtered current position data can replace the original detection data of the position detection device by utilizing the covariance matrix and the optimal state estimation value, so that the detection data is more accurate and reliable and is closer to the coordinate value of the real position. Then, simple workpiece processing is carried out, the precision condition of the workpiece processed by the coordinate data of the grating ruler is compared, a control program is finely adjusted according to the actual working condition, (such as a covariance value Q of process noise, an initial covariance value and the like), and the positioning coordinate of the feeding shaft can be more accurate by adjusting the control program.
Example two
Fig. 3 is a schematic diagram of an alternative positioning device for a machine tool according to an embodiment of the present invention, as shown in fig. 3, the positioning device may include: an acquisition unit 31, a determination unit 33, a filtering unit 35, a positioning unit 37, wherein,
an obtaining unit 31, configured to obtain current position data of a feed shaft of a target machine tool and a last detection filter value, where the last detection filter value is a filter base value obtained in a last interval duration;
a determination unit 33 for determining an error accuracy in acquiring the current position data of the feed shaft;
the filtering unit 35 is configured to perform filtering processing on the current position data based on the error precision and the detected filtering value to obtain coordinate data of the feed axis;
a positioning unit 37 for positioning the current coordinates of the feed axis of the target machine tool based on the coordinate data of the feed axis.
The positioning device of the machine tool can acquire the current position data of the feed shaft of the target machine tool and the detection filter value in the last time through the acquisition unit 31, then determine the error precision when the current position data of the feed shaft is acquired through the determination unit 33, filter the current position data through the filter unit 35 based on the error precision and the detection filter value to obtain the coordinate data of the feed shaft, and finally position the current coordinate of the feed shaft of the target machine tool based on the coordinate data of the feed shaft through the positioning unit 37. In the embodiment, the detected position data can be subjected to filtering processing in real time, and in combination with the last detection filtering value, more accurate position data closer to an actual state can be further obtained on the error precision of the detection equipment, the current coordinate of the feed shaft is determined by using the filtered coordinate data, the accumulated error of long-time continuous work of the feed shaft is reduced, and the control precision of the feed shaft is further improved, so that the technical problem that unqualified products are caused due to the fact that the accumulated error of components is easily received by the coordinate positioning precision of the machine tool feed shaft in the related technology is solved.
Optionally, the obtaining unit includes: the acquisition module is used for acquiring the position coordinates of the feed shaft of the target machine tool by adopting position detection equipment to obtain current position data; and the extraction module is used for extracting the filtering data when the current position data of the feed shaft is acquired within the last interval duration to obtain the last detection filtering value.
In an embodiment of the present invention, the determining unit includes: the first determination module is used for determining the pitch and deviation parameters of each turn of a ball screw of a feeding shaft on a target machine tool; and the first calculation module is used for calculating the error precision of the feed shaft when the feed shaft runs to reach the preset distance length based on the screw pitch and the deviation parameter.
Alternatively, the filtering unit includes: the first prediction module is used for predicting the running state value of the feed shaft of the target machine tool at the current moment based on the last detection filter value; the second determining module is used for determining the transfer relationship of the multiple operation influence factors at the current moment; the third determination module is used for determining position observation data of the feeding shaft based on the running state value and the coordinate data at the current moment; the second calculation module is used for calculating filtering gain data based on the position observation data and the transfer relation; the third calculation module is used for calculating the running state estimated value and the covariance matrix of the feed shaft at the current moment based on the filter gain data and the position observation data; and the fourth determination module is used for determining the coordinate data of the feed shaft based on the covariance matrix and the running state estimated value at the current moment.
Optionally, the first prediction module includes: the first obtaining submodule is used for obtaining a state transition matrix, a control matrix and a control vector of the target machine tool during operation, wherein the state transition matrix is used for indicating movement data of a feed shaft of the target machine tool in a preset distance length range, the control matrix is used for indicating control data for controlling the feed shaft of the target machine tool in operation, and the control vector is used for indicating a vector parameter for controlling the movement direction and the movement coordinate of the feed shaft; a first determining submodule for determining process noise of the target machine tool during operation based on the error accuracy; and the prediction submodule is used for predicting the running state value of the feed shaft of the target machine tool at the current moment based on the state transition matrix, the last detection filtering value, the control matrix, the control vector and the process noise.
In an embodiment of the present invention, the second determining module includes: the second acquisition submodule is used for acquiring the covariance matrix of the last time and the covariance of the process noise; and the second determining submodule is used for determining the transfer relationship of the plurality of operation influence factors at the current moment based on the state transition matrix of the target machine tool in operation, the previous covariance matrix and the covariance of the process noise.
Optionally, the second obtaining sub-module is configured to include: the calculation submodule is used for calculating the difference value between the last position observation value and the initial position prediction value to obtain a position difference value; a third determining submodule, configured to use a result of a square operation of the position difference as a previous covariance; and the construction submodule is used for constructing a covariance matrix of the last time based on the covariance of the last time and the covariance of the initial time.
The above-mentioned positioning device for a machine tool may further include a processor and a memory, the above-mentioned acquiring unit 31, the determining unit 33, the filtering unit 35, the positioning unit 37, and the like are all stored in the memory as program units, and the processor executes the above-mentioned program units stored in the memory to implement corresponding functions.
The processor comprises a kernel, and the kernel calls a corresponding program unit from the memory. The kernel can be set to one or more, and the current coordinates of the feed shaft of the target machine tool are positioned based on the coordinate data of the feed shaft by adjusting the kernel parameters.
The memory may include volatile memory in a computer readable medium, Random Access Memory (RAM) and/or nonvolatile memory such as Read Only Memory (ROM) or flash memory (flash RAM), and the memory includes at least one memory chip.
According to another aspect of the embodiments of the present invention, there is also provided a machine tool apparatus including: a processor; and a memory for storing executable instructions for the processor; wherein the processor is configured to perform the method of positioning of a machine tool of any of the above via execution of the executable instructions.
According to another aspect of the embodiments of the present invention, there is also provided a computer-readable storage medium including a stored computer program, wherein when the computer program is executed, the apparatus on which the computer-readable storage medium is located is controlled to execute the positioning method of the machine tool according to any one of the above items.
The present application further provides a computer program product adapted to perform a program for initializing the following method steps when executed on a data processing device: acquiring current position data of a feed shaft of a target machine tool and a last detection filter value, wherein the last detection filter value is a filter basic value obtained in a last interval duration; determining an error accuracy in acquiring current position data of the feed shaft; based on the error precision and the detection filter value, carrying out filter processing on the current position data to obtain coordinate data of the feed shaft; based on the coordinate data of the feed axis, the current coordinates of the feed axis of the target machine tool are located.
The above-mentioned serial numbers of the embodiments of the present invention are merely for description and do not represent the merits of the embodiments.
In the above embodiments of the present invention, the descriptions of the respective embodiments have respective emphasis, and for parts that are not described in detail in a certain embodiment, reference may be made to related descriptions of other embodiments.
In the embodiments provided in the present application, it should be understood that the disclosed technology can be implemented in other ways. The above-described embodiments of the apparatus are merely illustrative, and for example, the division of the units may be a logical division, and in actual implementation, there may be another division, for example, multiple units or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, units or modules, and may be in an electrical or other form.
The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.
In addition, functional units in the embodiments of the present invention may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit. The integrated unit can be realized in a form of hardware, and can also be realized in a form of a software functional unit.
The integrated unit, if implemented in the form of a software functional unit and sold or used as a stand-alone product, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present invention may be embodied in the form of a software product, which is stored in a storage medium and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the method according to the embodiments of the present invention. And the aforementioned storage medium includes: a U-disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a removable hard disk, a magnetic or optical disk, and other various media capable of storing program codes.
The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.
Claims (10)
1. A method of positioning a machine tool, comprising:
acquiring current position data of a feed shaft of a target machine tool and a last detection filter value, wherein the last detection filter value is a filter basic value obtained in a last interval duration;
determining an error accuracy in acquiring the current position data of the feed shaft;
based on the error precision and the detection filtering value, filtering the current position data to obtain coordinate data of the feed shaft;
and positioning the current coordinates of the feed shaft of the target machine tool based on the coordinate data of the feed shaft.
2. The positioning method according to claim 1, wherein the step of obtaining the current position data of the feed axis of the target machine tool and the last detected filtered value comprises:
acquiring the position coordinate of the feed shaft of the target machine tool by adopting position detection equipment to obtain the current position data;
and extracting the filtering data when the current position data of the feed shaft is obtained in the last interval duration to obtain the last detection filtering value.
3. The positioning method according to claim 1, wherein the step of determining the accuracy of the error in acquiring the current position data of the feed shaft comprises:
determining the pitch and deviation parameters of each turn of a ball screw of a feed shaft on the target machine tool;
and calculating the error precision of the feed shaft when the feed shaft runs to reach the preset distance length based on the screw pitch and the deviation parameter.
4. The positioning method according to claim 1, wherein the step of performing filtering processing on the current position data to obtain the coordinate data of the feed axis includes:
predicting the running state value of the feed shaft of the target machine tool at the current moment based on the last detection filter value;
determining the transfer relationship of a plurality of operation influence factors at the current moment;
determining position observation data of the feeding shaft based on the running state value of the current moment and the coordinate data;
calculating filter gain data based on the position observation data and the transfer relationship;
calculating an estimated value of the running state of the feed shaft at the current moment and a covariance matrix based on the filter gain data and the position observation data;
and determining the coordinate data of the feed shaft based on the covariance matrix and the estimated value of the running state at the current moment.
5. The positioning method according to claim 4, wherein the step of predicting the operation state value of the feed axis of the target machine tool at the current time based on the last detected filtered value comprises:
acquiring a state transition matrix, a control matrix and a control vector of the target machine tool during operation, wherein the state transition matrix is used for indicating movement data of a feed shaft of the target machine tool in a preset distance length range, the control matrix is used for indicating control data for controlling the operation of the feed shaft of the target machine tool, and the control vector is used for indicating a vector parameter for controlling the movement direction and the movement coordinate of the feed shaft;
determining process noise of the target machine tool while running based on the error accuracy;
and predicting the running state value of the feed shaft of the target machine tool at the current moment based on the state transition matrix, the last detection filtering value, the control matrix, the control vector and the process noise.
6. The method of claim 5, wherein the step of determining the transfer relationship of the plurality of operational influencing factors at the current time comprises:
acquiring a covariance matrix of the last time and a covariance of the process noise;
and determining the transfer relationship of a plurality of operation influence factors at the current moment based on the state transition matrix of the target machine tool in operation, the previous covariance matrix and the covariance of the process noise.
7. The method of claim 6, wherein the step of obtaining the covariance matrix of the last time and the covariance of the process noise comprises:
calculating a difference value between the last position observation value and the initial position prediction value to obtain a position difference value;
taking the square operation result of the position difference value as the covariance of the last time;
and constructing a previous covariance matrix based on the previous covariance and the covariance of the initial moment.
8. A positioning device for a machine tool, comprising:
the device comprises an acquisition unit, a processing unit and a control unit, wherein the acquisition unit is used for acquiring current position data of a feed shaft of a target machine tool and a last detection filter value, and the last detection filter value refers to a filter basic value obtained in a last interval duration;
a determination unit configured to determine an error accuracy in acquiring the current position data of the feed shaft;
the filtering unit is used for carrying out filtering processing on the current position data based on the error precision and the detection filtering value to obtain coordinate data of the feed shaft;
and the positioning unit is used for positioning the current coordinate of the feed shaft of the target machine tool based on the coordinate data of the feed shaft.
9. A machine tool apparatus, comprising:
a processor; and
a memory for storing executable instructions of the processor;
wherein the processor is configured to perform the method of positioning of a machine tool of any one of claims 1 to 7 via execution of the executable instructions.
10. A computer-readable storage medium, comprising a stored computer program, wherein the computer program, when executed, controls an apparatus in which the computer-readable storage medium is located to perform the method of positioning a machine tool of any one of claims 1 to 7.
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