CN117884949A - Error compensation method and five-axis machine tool - Google Patents

Error compensation method and five-axis machine tool Download PDF

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Publication number
CN117884949A
CN117884949A CN202410063745.6A CN202410063745A CN117884949A CN 117884949 A CN117884949 A CN 117884949A CN 202410063745 A CN202410063745 A CN 202410063745A CN 117884949 A CN117884949 A CN 117884949A
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China
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plane
angle
rotation
axis
error
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CN202410063745.6A
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Chinese (zh)
Inventor
石浚
尹斌
陈海生
黄得凯
陈磊
李信
解德玢
刘志恒
彭小辉
王兵
李岩
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Fuxiang Precision Industrial Kunshan Co Ltd
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Fuxiang Precision Industrial Kunshan Co Ltd
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Priority to CN202410063745.6A priority Critical patent/CN117884949A/en
Publication of CN117884949A publication Critical patent/CN117884949A/en
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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
    • B23Q17/00—Arrangements for observing, indicating or measuring on machine tools
    • G—PHYSICS
    • G05—CONTROLLING; REGULATING
    • G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
    • G05B19/00—Programme-control systems
    • G05B19/02—Programme-control systems electric
    • G05B19/18—Numerical control [NC], i.e. automatically operating machines, in particular machine tools, e.g. in a manufacturing environment, so as to execute positioning, movement or co-ordinated operations by means of programme data in numerical form
    • G05B19/404—Numerical control [NC], i.e. automatically operating machines, in particular machine tools, e.g. in a manufacturing environment, so as to execute positioning, movement or co-ordinated operations by means of programme data in numerical form characterised by control arrangements for compensation, e.g. for backlash, overshoot, tool offset, tool wear, temperature, machine construction errors, load, inertia

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  • Engineering & Computer Science (AREA)
  • Human Computer Interaction (AREA)
  • Manufacturing & Machinery (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Automation & Control Theory (AREA)
  • Mechanical Engineering (AREA)
  • Numerical Control (AREA)

Abstract

The application provides an error compensation method and a five-axis machine tool. The method comprises the following steps: selecting a plane to be compensated from a detection jig mounted on a five-axis machine tool, and calculating initial coordinates of an intersection point between the hole and the plane to be compensated according to the depth of the hole, the center coordinates and a plane equation of a reference plane of the detection jig if the plane to be compensated is an open plane; controlling the plane to be compensated to rotate through the first rotation angle and the second rotation angle; controlling the rotation of the rotated plane to be compensated to be a horizontal plane based on a first error angle and a second error angle which are calculated by a preset vector, a first rotation angle, a second rotation angle and a normal vector of the rotated plane to be compensated; the absolute coordinate system of the detection jig is compensated based on the position degree error value calculated from the initial coordinate, the first error angle, the second error angle, and the actual coordinate of the intersection point on the horizontal plane. By using the method, the error compensation can be effectively carried out on the machine tool, and the machining precision of the five-axis machine tool can be improved.

Description

Error compensation method and five-axis machine tool
Technical Field
The application relates to the technical field of numerical control machine tools, in particular to an error compensation method and a five-axis machine tool.
Background
The five-axis machine tool is a machine tool capable of moving and rotating in multiple directions, and can be used for processing complex workpieces with high precision. In the process of machining a workpiece by using a five-axis machine tool, certain errors may be caused by the rotation axis and the linear axis of the machine tool, and the errors may be caused by factors such as the structure of the machine tool itself, the change of the working environment, the material characteristics and the like. The five-axis machine tool in the related art lacks a compensation algorithm, so that error compensation is difficult to effectively carry out on the machine tool, and the machining precision of a workpiece is influenced.
Disclosure of Invention
In view of the foregoing, it is necessary to provide an error compensation method and a five-axis machine tool that can solve the technical problem that it is difficult to effectively compensate for errors of the machine tool, resulting in the influence of the machining accuracy of a workpiece.
In one aspect, the present application provides an error compensation method applied to a five-axis machine tool, a surface of the five-axis machine tool is provided with a detection jig with corrected reference surfaces, a plane of the detection jig includes a plurality of reference surfaces parallel to a coordinate axis plane of a machine tool coordinate system of the five-axis machine tool, and each reference surface is parallel to a coordinate axis plane, the method includes: selecting any plane of the detection jig as a plane to be compensated, acquiring a first rotation angle and a second rotation angle of the plane to be compensated, wherein the first rotation angle corresponds to a first rotation axis of the five-axis machine tool, the second rotation angle corresponds to a second rotation axis of the five-axis machine tool, if the plane to be compensated is an open plane, measuring a center coordinate of a center point in a hole of the plane to be compensated, calculating an intersecting coordinate of an intersecting point between a central axis of the hole and the plane to be compensated according to a depth of the hole and the center coordinate, calculating a projection distance between the intersecting point and each reference plane according to a plane equation of the intersecting coordinate and each reference plane, determining an initial coordinate of the intersecting point according to a plurality of projection distances, controlling the first rotation axis to rotate by the first rotation angle, controlling the second rotation axis by the second rotation angle, rotating the plane to be compensated, measuring coordinates of a plurality of points on the plane to be compensated after rotation, calculating an intersecting point according to a preset angle, calculating an error vector of the second rotation axis, calculating a second rotation axis, and calculating a normal vector by the second rotation axis, and calculating an error vector by the first rotation axis, and calculating a normal vector by the second rotation axis, and the error vector And calculating a standard coordinate of the intersection point on the horizontal plane, measuring an actual coordinate of the intersection point on the horizontal plane, calculating a position error value corresponding to the hole according to the standard coordinate and the actual coordinate, and compensating an absolute coordinate system of the detection jig based on the position error value.
In some embodiments of the application, the detection jig is mounted on a disk surface of the second rotation shaft, and a center of the detection jig is located on a rotation center of the second rotation shaft.
In some embodiments of the present application, the calculating, based on the preset vector, the first rotation angle, the second rotation angle, and the normal vector, a first error angle of the plane to be compensated corresponding to the first rotation axis and a second error angle of the plane to be compensated corresponding to the second rotation axis includes: constructing a rotation matrix according to the first rotation angle, a first parameter corresponding to the first error angle and a second parameter corresponding to the second error angle, establishing a parameter equation according to the preset vector, the rotation matrix and the normal vector, solving the parameter equation to obtain a first parameter value of the first parameter and a second parameter value of the second parameter, calculating an updated first rotation angle according to the first parameter value and the first rotation angle, and calculating the first error angle and the second error angle based on the preset vector, the updated first rotation angle, the second rotation angle and the normal vector.
In some embodiments of the application, the rotation matrix is expressed as:
Wherein denotes the rotation matrix,/> denotes the first rotation angle, θ A denotes the first parameter, and θ C denotes the second parameter.
In some embodiments of the application, the parameter equation is expressed as:
Wherein denotes the rotation matrix,/> denotes the normal vector, and/> denotes the preset vector.
In some embodiments of the present application, the method for calculating standard coordinates includes:
Wherein P 1 'represents the standard coordinate, a represents the first error angle, X' represents the abscissa in the initial coordinate, Y 'represents the ordinate in the initial coordinate, Z' represents the ordinate in the initial coordinate, and c represents the second error angle.
In some embodiments of the present application, the calculating the position error value corresponding to the hole according to the standard coordinates and the actual coordinates includes: and determining a difference value between the standard coordinates and the actual coordinates as the position degree error value.
In some embodiments of the present application, the compensating the absolute coordinate system of the detection jig based on the position error value includes: and adjusting the origin of the absolute coordinate system according to the position error value.
In some embodiments of the present application, the controlling the first rotation axis to rotate by the first rotation angle and the controlling the second rotation axis to rotate by the second rotation angle includes: generating a numerical control instruction according to the first rotation angle and the second rotation angle, and controlling the first rotation shaft and the second rotation shaft to rotate by executing the numerical control instruction, so that the plane to be compensated rotates.
In another aspect, the present application provides a five-axis machine tool comprising: a memory storing at least one instruction; and a controller executing the at least one instruction to implement the error compensation method.
In the above embodiment, the first error angle of each plane with respect to the first rotation axis and the second error angle of the second rotation axis can be calculated for each plane of the inspection jig, and when each plane of the inspection jig or the workpiece is required to be processed, the plane to be processed can be rotated to the horizontal plane, so that the processing precision of the five-axis machine tool can be improved. When the plane of the detection jig or the workpiece is an open hole plane, the position error value of each hole in the open hole plane can be calculated. When each hole of the hole plane of the workpiece is required to be processed, the absolute coordinate system of the detection jig is compensated based on the position error value of each hole, so that the processing precision of the five-axis machine tool can be further improved. In addition, the absolute coordinate system of the detection jig is directly compensated through the position error value, so that the modification time of a program can be reduced, and the processing speed can be improved.
Drawings
Fig. 1 is a schematic diagram of a detection tool after reference plane correction according to an embodiment of the present application.
Fig. 2 is a flowchart of an error compensation method according to an embodiment of the present application.
Fig. 3 is a schematic diagram of a plane to be compensated after rotation according to an embodiment of the present application.
Fig. 4 is a schematic diagram of a plane to be compensated after being rotated again according to an embodiment of the present application.
Fig. 5 is a flowchart of a method for calculating a first error angle and a second error angle according to an embodiment of the present application.
FIG. 6 is a functional block diagram of an error compensation device according to an embodiment of the present application.
Fig. 7 is a schematic structural diagram of a numerical control system of a five-axis machine tool according to an embodiment of the present application.
Detailed Description
In order to make the objects, technical solutions and advantages of the present application more apparent, the present application will be described in detail with reference to the accompanying drawings and specific embodiments.
In the present application, "at least one" means one or more, and "a plurality" means two or more. "and/or", describes an association relationship of an association object, and the representation may have three relationships, for example, a and/or B may represent: a alone, a and B together, and B alone, wherein a, B may be singular or plural. The terms "first," "second," "third," "fourth" and the like in the description and in the claims and drawings, if any, are used for distinguishing between similar objects and not necessarily for describing a particular sequential or chronological order.
In embodiments of the application, words such as "exemplary" or "such as" are used to mean serving as an example, instance, or illustration. Any embodiment or design described herein as "exemplary" or "e.g." in an embodiment should not be taken as preferred or advantageous over other embodiments or designs. Rather, the use of words such as "exemplary" or "such as" is intended to present related concepts in a concrete fashion.
The five-axis machine tool is a machine tool capable of moving and rotating in multiple directions, and can be used for processing complex workpieces with high precision. In the process of machining a workpiece by using a five-axis machine tool, certain errors may be caused by the rotation axis and the linear axis of the machine tool, and the errors may be caused by factors such as the structure of the machine tool itself, the change of the working environment, the material characteristics and the like. The five-axis machine tool in the related art lacks a compensation algorithm, so that error compensation is difficult to effectively carry out on the machine tool, and the machining precision of a workpiece is influenced.
In order to solve the technical problems, the application provides an error compensation method and a five-axis machine tool, which can effectively compensate errors of the machine tool and improve the machining precision of the five-axis machine tool. The error compensation method provided by the embodiment of the application can be applied to one or more five-axis machine tools.
The five-axis machine tool comprises five machining axes which are respectively a transverse axis, a longitudinal axis, a vertical axis and a plurality of rotating shafts, and the five machining axes are used as coordinate axes to form coordinate axes of a machine tool coordinate system of the five-axis machine tool. The five-axis machine tool in the embodiment of the application can be a cradle-type five-axis machine tool, wherein the cradle-type five-axis machine tool refers to a workbench which has a shape and a movement mode similar to those of a cradle, and the cradle-type five-axis machine tool can be divided into an AC cradle-type five-axis machine tool and an AB cradle-type five-axis machine tool. The X axis of the AC cradle type five-axis machine tool represents the horizontal axis, the Y axis represents the vertical axis, the Z axis represents the vertical axis, and the plurality of rotating shafts of the AC cradle type five-axis machine tool comprise an A axis and a C axis. The X axis of the AB cradle type five-axis machine tool represents the horizontal axis, the Y axis represents the vertical axis, the Z axis represents the vertical axis, and the plurality of rotating shafts of the AC cradle type five-axis machine tool comprise an A axis and a B axis.
The X-axis is an axis of horizontal movement, and the workpiece is controlled to move in the horizontal direction by moving in the positive or negative direction along the X-axis. In addition, the X axis can enable the cutter to transversely move along the horizontal direction, and the cutting point on the workpiece is controlled in the machining process.
The Y-axis is an axis of vertical movement, and the workpiece is controlled to move in the vertical direction by moving in the positive or negative direction along the Y-axis. In addition, the Y-axis can enable the cutter to move up and down along the vertical direction, and the height adjustment of the workpiece is controlled.
The Z axis is an axis that moves in the main axis direction, and the workpiece is controlled to move in the Z axis direction by moving in the positive or negative direction of the Z axis. In addition, the Z-axis may advance or retract the tool in the spindle direction for controlling the depth of cut and the accuracy of the machined surface.
The a-axis is an axis rotating around the X-axis for controlling the inclination angle of the workpiece. By rotating the A-axis, the workpiece can be inclined, and cutting operations such as inclined planes, chamfering and the like at different angles can be realized.
The C-axis is an axis rotating around the Z-axis for controlling the turning angle of the workpiece. By rotating the C-axis, the workpiece can be rotated on a plane perpendicular to the main axis for performing a cutting operation of a circular or curved shape, such as thread processing, arc processing, or the like.
The B axis is an axis that rotates around the Y axis, and by rotating the B axis, the workpiece can be made to perform rotational movement on a plane perpendicular to the horizontal plane. The B-axis may be used to achieve more degrees of machining freedom, such as tilting, complex curved machining, and the like.
For convenience of description, an AC cradle type five-axis machine tool will be taken as an example, and an error compensation method in an embodiment of the present application will be described. The detection jig after the correction of the reference surface is installed on the disk surface of the five-axis machine tool, and the detection jig is installed on the disk surface of the C axis, so that the center of the detection jig is positioned on the rotation center of the C axis. The rotation center refers to a reference point of the five-axis machine tool for detection and positioning, and can be regarded as a machining origin. The five-axis machine tool comprises an interface fixture, so that the five-axis machine tool can be quickly abutted with the detection fixture (product or workpiece), and the processing of the detection fixture (workpiece or product) is not affected.
The plane of the detection jig comprises a plurality of reference planes parallel to the coordinate axis plane of the machine tool coordinate system of the five-axis machine tool, and each reference plane is parallel to one coordinate axis plane. The detection jig is obtained by matching and designing the clamping mode of a product (workpiece) to be processed and a five-axis machine tool. The inspection jig may include an open plane and a non-porous plane, the open plane may include one or more holes, and the non-porous plane may have no holes. The detection jig (workpiece or product) has a corresponding absolute coordinate system, and the absolute coordinate system uses a preset reference point on the detection jig as an origin for describing the position and direction of the detection jig. The preset reference point can be set by itself, which is not limited by the present application.
For example, as shown in fig. 1, a schematic diagram of a detection tool after reference plane correction according to an embodiment of the application is shown. The inspection jig in fig. 1 has 15 planes (planes 1-4 and 14-15 are not shown for angle reasons) in total, including 3 reference planes, reference plane a, reference plane B and reference plane C, respectively. The reference plane A is parallel to a coordinate axis plane formed by an X axis and a Y axis of the five-axis machine tool, the reference plane B is parallel to a coordinate axis plane formed by an X axis and a Z axis of the five-axis machine tool, and the reference plane C is parallel to a coordinate axis plane formed by a Y axis and a Z axis of the five-axis machine tool. After the detection jig is installed, the reference plane A is a horizontal plane, and the rotation angles of the A axis and the C axis are 0 degrees at the moment. The XC axis in fig. 1 is the horizontal axis of an absolute coordinate system (for example, the absolute coordinate system may be a G355 coordinate system for describing the position and direction of the detection jig), the YC axis is the vertical axis of the absolute coordinate system, and the ZC axis is the vertical axis of the absolute coordinate system.
Fig. 2 is a flowchart of an error compensation method according to an embodiment of the present application. The sequence of the steps in the flowchart may be adjusted according to actual requirements, and some steps may be omitted. The execution subject of the method may be a five-axis machine tool.
S10, selecting any plane of the detection jig as a plane to be compensated, and acquiring a first rotation angle and a second rotation angle of the plane to be compensated, wherein the first rotation angle corresponds to the first rotation shaft, and the second rotation angle corresponds to the second rotation shaft.
In an AC-type cradle five-axis machine, the first axis of rotation may be the a-axis, the second axis of rotation may be the C-axis, or in an AB-type cradle five-axis machine, the first axis of rotation may be the a-axis, and the second axis of rotation may be the B-axis. The first rotation angle and the second rotation angle may be collectively referred to as "theoretical compound angles" of the a axis and the C axis, and the first rotation angle and the second rotation angle are theoretical angles that enable the plane to be compensated to rotate into a horizontal plane. The first rotation angle and the second rotation angle may be preset, or the first rotation angle and the second rotation angle may be obtained through user input, which is not limited in the present application. For example, the first angle of rotation may be and the second angle of rotation may be/>
In this embodiment, due to errors and other reasons, it is difficult for the first rotation angle and the second rotation angle in theory to make the plane to be compensated rotate to be a real horizontal plane, so the a axis is controlled to rotate through the first rotation angle, and the C axis is controlled to rotate through the second rotation angle, so that after the plane to be compensated rotates, the plane to be compensated after rotation is only a theoretical horizontal plane.
S11, if the plane to be compensated is an open plane, measuring the center coordinates of the center point in the hole of the plane to be compensated, and calculating the intersection coordinates of the intersection point between the central axis of the hole and the plane to be compensated according to the depth and the center coordinates of the hole.
In some embodiments of the present application, the plane of the inspection tool may include an open plane including one or more holes and a non-hole plane not including holes. The number of the holes in each hole plane can be one or more, the holes can be round or other shapes, and the shape of the holes is not limited by the application. The holes can be blind holes or other types of holes, and the application is not limited to the types of holes. The center point in the hole refers to the point where the central axis of the hole intersects the bottom of the hole. For example, the plane of the openings may be the 5 th, 6 th, 7 th and 13 th planes in fig. 1.
In some embodiments of the present application, a five-axis machine tool may obtain the center coordinates of the center point by controlling one or more machine axes to move such that the probe head (stylus) of the five-axis machine tool reaches the center point of the hole and triggers a measurement operation. The probe comprises a trigger and a sensor, and the center coordinate of the center point can be obtained by contacting the center point or emitting laser to the center point. The application does not limit the measuring mode of the probe.
In some embodiments of the present application, the five-axis machine tool may perform an addition operation on the vertical coordinate of the center coordinate and the depth of the hole to obtain the intersection coordinate of the intersection point. For example, if the center coordinate is P 0(x0,y0,z0), the depth of the hole is h, and the intersection coordinate of the intersection point is P 0(x0,y0,z0 +h).
After the detection jig is mounted on the five-axis machine tool, the rotation angles of the A axis and the C axis of the five-axis machine tool are 0 degrees, and the reference plane A is a horizontal plane, so that the central coordinates of the central point of the hole are acquired when the rotation angles of the A axis and the C axis are 0 degrees.
In other embodiments of the present application, if the plane to be compensated is a non-porous plane, the center coordinates of the center point in the hole of the plane to be compensated are not measured, and the depth and the center coordinates of the hole are determined.
For ease of illustration, the process of calculating the compensation error is described below using only a single plane to be compensated (e.g., plane 5).
And S12, calculating the projection distance between the intersection point and each datum plane according to the intersection coordinates and the plane equation of each datum plane, and determining the initial coordinates of the intersection point according to the plurality of projection distances.
In some embodiments of the application, the plane equation for each reference plane is calculated from coordinates of a plurality of points on the reference plane or may be input by a user. The calculation method of the plane equation may refer to the related art, and the present application is not limited thereto.
The projection distance is the shortest distance from the intersection point to each reference plane. For example, in the above embodiment, if the intersection coordinate is P 0(x0,y0,z0 +h, the plane equation of the reference plane a is a Ax+bAy+cAz+dA, and the calculation method of the projection distance between the intersection point and the reference plane a may refer to formula (1):
Where distance (P 0, A) represents the projected distance between the intersection point and the reference plane A.
In this embodiment, if the origin of the absolute coordinate system corresponding to the detection jig is at the rotation center of the five-axis machine tool, the five-axis machine tool may determine a first projection distance (P 0, C) between the intersection point and the reference plane C as an abscissa X ' of the initial coordinate, determine a second projection distance (P 0, B) between the intersection point and the reference plane B as an ordinate Y ' of the initial coordinate, and determine a third projection distance (P 0, a) between the intersection point and the reference plane a as an ordinate Z ' of the initial coordinate, thereby obtaining an initial coordinate P 0 ' (X ', Y ', Z ').
In other embodiments of the present application, if the distance between the origin of the absolute coordinate system corresponding to the detection jig and the rotation center of the five-axis machine tool is H, the five-axis machine tool may determine the first projection distance (P 0, C) as the abscissa X ' of the initial coordinate, determine the second projection distance (P 0, B) as the ordinate Y ' of the initial coordinate, and determine the difference H-distance (P 0, a) between the distance H and the third projection distance (P 0, a) as the ordinate Z ' of the initial coordinate, thereby obtaining the initial coordinate P 0 ' (X ', Y ', Z ').
S13, controlling the first rotating shaft to rotate through the first rotating angle, and controlling the second rotating shaft to rotate through the second rotating angle, so that the plane to be compensated rotates.
In this embodiment, the five-axis machine tool may generate a numerical control instruction (Numerical Control, NC) according to the first rotation angle and the second rotation angle, and control the first rotation axis and the second rotation axis to rotate by executing the numerical control instruction, so that the plane to be compensated rotates.
For example, if the plane to be compensated is the 5 th plane, as shown in fig. 3, a schematic diagram of the plane to be compensated after rotation according to an embodiment of the present application is shown. As can be seen from fig. 3, the a-axis is controlled to rotate by a first rotation angle and the C-axis is controlled to rotate by a second rotation angle such that after the 5 th plane is rotated, the rotated 5 th plane is not a horizontal plane.
S14, measuring coordinates of a plurality of points on the rotated plane to be compensated, and calculating normal vectors of the rotated plane to be compensated according to the coordinates of the plurality of points.
In some embodiments of the application, the plurality of points measured may be a plurality of points that are not collinear on the plane to be compensated after rotation. In order to be able to calculate the normal vector, the number of points is greater than or equal to three. The method of measuring the coordinates of the plurality of points is substantially the same as the method of measuring the center coordinates of the center point, so the description of the present application will not be repeated here.
For example, if the coordinates of three non-collinear points are measured as Pa＝(xa,ya,za),Pb＝(xb,yb,zb),Pc＝(xc,yc,zc), normal vectors, the following formula (2) can be referred to:
N＝(xb-xa,yb-ya,zb-za)×(xc-xa,yc-ya,zb-zc); (2)
Where N represents a normal vector.
In this embodiment, by selecting coordinates of a plurality of points that are not collinear on the rotated plane to be compensated, the normal vector of the rotated plane to be compensated can be accurately calculated.
S15, calculating a first error angle of the plane to be compensated corresponding to the first rotating shaft and a second error angle of the plane to be compensated corresponding to the second rotating shaft based on the preset vector, the first rotating angle, the second rotating angle and the normal vector.
In the present embodiment, since the first error angle refers to the difference between the ideal rotation angle (first rotation angle) of the first rotation shaft required to rotate the plane to be compensated to the horizontal plane and the angle actually required to rotate, the second error angle refers to the difference between the ideal rotation angle (second rotation angle) of the second rotation shaft required to rotate the plane to be compensated to the horizontal plane and the angle actually required to rotate.
In this embodiment, for each plane to be compensated, a corresponding first error angle and a corresponding second error angle can be calculated. The first error angle is a compensation angle corresponding to the first rotation axis, and the second error angle is a compensation angle corresponding to the second rotation axis.
S16, controlling the first rotating shaft to rotate through a first error angle, and controlling the second rotating shaft to rotate through a second error angle, so that the rotated plane to be compensated rotates to be a horizontal plane.
The first error angle refers to a gap between an ideal rotation angle (first rotation angle) of the first rotation shaft required for rotating the plane to be compensated into a horizontal plane and an angle required to be rotated actually, and the second error angle refers to a gap between an ideal rotation angle (second rotation angle) of the second rotation shaft required for rotating the plane to be compensated into a horizontal plane and an angle required to be rotated actually, so that the first rotation shaft is controlled to rotate through the first error angle, the second rotation shaft is controlled to rotate through the second error angle, the rotated plane to be compensated is rotated again, and the plane to be compensated after the re-rotation is enabled to be the horizontal plane.
For example, if the plane to be compensated is the 5 th plane, as shown in fig. 4, a schematic diagram of the plane to be compensated after being rotated again according to an embodiment of the present application is shown. As can be seen from fig. 4, the plane 5 to be compensated can be rotated to a horizontal plane (positive horizontal plane) by controlling the a-axis to be rotated by a first error angle again on the basis of the first rotation angle and controlling the C-axis to be rotated by a second error angle again on the basis of the second rotation angle.
In some embodiments of the present application, the first rotation axis is controlled to rotate by a first error angle, and the second rotation axis is controlled to rotate by a second error angle, so that the plane to be compensated after rotation rotates to be a horizontal plane and the first rotation axis is controlled to rotate by the first rotation angle, and the second rotation axis is controlled to rotate by the second rotation angle, so that the plane to be compensated rotates substantially the same, and therefore, the description of the present application is not repeated.
In this embodiment, the first rotation axis is controlled to rotate by the first error angle, and the second rotation axis is controlled to rotate by the second error angle, so that compensation for the first rotation axis and the second rotation axis can be achieved, the rotated plane to be compensated rotates to be a horizontal plane, and error compensation for the first rotation axis and the second rotation axis is achieved.
In other embodiments of the present application, after the first rotation axis is controlled to rotate by the first error angle and the second rotation axis is controlled to rotate by the second error angle, coordinates of a plurality of points on a plane to be compensated (for example, a 5 th plane) after the re-rotation are measured by a probe (refer to the probe in fig. 4), and whether the plane to be compensated after the re-rotation is a horizontal plane is determined according to the measured coordinates of the plurality of points, so as to determine whether the first error angle and the second error angle are accurate (precise), so as to perform the next compensation on the first rotation axis and the second rotation axis when the plane to be compensated after the re-rotation is a non-horizontal plane. Wherein, whether the plane to be compensated after the re-rotation is the horizontal plane is determined according to the measured coordinates of the plurality of points can refer to the related technology, and the application is not limited to the above.
S17, calculating the standard coordinate of the intersection point on the horizontal plane according to the initial coordinate, the first error angle and the second error angle of the intersection point.
In the present embodiment, the calculation formula of the standard coordinates can refer to formulas (3) to (4):
wherein P 1 'represents a standard coordinate, a represents a first error angle, X' represents an abscissa in an initial coordinate, Y 'represents an ordinate in the initial coordinate, Z' represents an ordinate in the initial coordinate, and c represents a second error angle.
S18, measuring the actual coordinates of the intersecting points on the horizontal plane, and calculating the position error value corresponding to the hole according to the standard coordinates and the actual coordinates.
In some embodiments of the present application, the position error value refers to the difference between the actual position (actual coordinates) of the hole and the corresponding ideal position (standard coordinates).
If the plane to be compensated is an open plane and a plurality of holes are formed in the plane to be compensated, each hole corresponds to an actual coordinate and a standard coordinate, and the five-axis machine tool can determine the difference between each standard coordinate and the corresponding actual coordinate as a position error value corresponding to each hole or determine the difference between each actual coordinate and the corresponding standard coordinate as a position error value corresponding to each hole. The application does not limit the calculation method of the position error value of each hole.
The position error value of each hole comprises a first position error value of the hole relative to a transverse axis (X axis), a second position error value relative to a longitudinal axis (Y axis) and a second position error value corresponding to a vertical axis (Z axis). For example, the first position degree error value may be a difference between each standard coordinate and an abscissa of the corresponding actual coordinate, the second position degree error value may be a difference between each standard coordinate and an ordinate of the corresponding actual coordinate, and the third position degree error value may be a difference between each standard coordinate and an ordinate of the corresponding actual coordinate.
And S19, compensating an absolute coordinate system of the detection jig based on the position error value.
In some embodiments of the present application, the absolute coordinate system (e.g., G355 coordinate system in fig. 1) is a coordinate system with a preset reference point on the inspection jig (product or workpiece) as an origin, for describing the position and direction of the inspection jig. The preset reference point can be set by itself, which is not limited by the present application.
In some embodiments of the application, compensating the absolute coordinate system of the detection jig based on the compensation error comprises: and adjusting the origin of the absolute coordinate system according to each position error value.
In this embodiment, each plane to be compensated has a corresponding first error angle and a second error angle, and if the plane to be compensated is an open plane, the position error value corresponding to each hole on the plane to be compensated can also be calculated.
In the above embodiment, the first error angle of each plane with respect to the first rotation axis and the second error angle of the second rotation axis can be calculated for each plane of the inspection jig, and when each plane of the inspection jig or the workpiece is required to be processed, the plane to be processed can be rotated to the horizontal plane, so that the processing precision of the five-axis machine tool can be improved. When the plane of the detection jig or the workpiece is an open hole plane, the position error value of each hole in the open hole plane can be calculated. When each hole of the hole plane of the workpiece is required to be processed, the absolute coordinate system of the detection jig is compensated based on the position error value of each hole, so that the processing precision of the five-axis machine tool can be further improved. In addition, the absolute coordinate system of the detection jig is directly compensated through the position error value, so that the modification time of a program can be reduced, and the processing speed can be improved.
Fig. 5 is a flowchart of a method for calculating a first error angle and a second error angle according to an embodiment of the present application.
S161, constructing a rotation matrix according to the first rotation angle, the first parameter corresponding to the first error angle and the second parameter corresponding to the second error angle.
In this embodiment, the rotation matrix may be expressed as formula (5) shown below:
Wherein denotes a rotation matrix,/> denotes a first rotation angle, θ A denotes the first parameter, and θ C denotes a second parameter.
S162, establishing a parameter equation according to the preset vector, the rotation matrix and the normal vector.
In the present embodiment, the parameter equation may be expressed as formula (6) shown below:
Wherein denotes a rotation matrix,/> denotes a normal vector, and/> denotes a preset vector.
S163, solving the parameter equation to obtain a first parameter value of the first parameter and a second parameter value of the second parameter.
In this embodiment, since the rotation matrix includes the first parameter and the second parameter, the first parameter value of the first parameter and the second parameter value of the second parameter can be obtained by simplifying and solving the above.
S164, calculating an updated first rotation angle according to the first parameter value and the first rotation angle.
In some embodiments of the application, the five-axis machine tool may determine a difference between the first rotation angle and the first parameter value as an updated first rotation angle.
In the present embodiment, since there is an error in the first rotation angle, determining the difference between the first rotation angle and the first parameter value as the updated first rotation angle can reduce the error in the updated first rotation angle.
S165, calculating a first error angle and a second error angle based on the preset vector, the updated first rotation angle, the updated second rotation angle and the normal vector.
In this embodiment, the calculation methods of the first error angle and the second error angle are substantially the same as the calculation methods of the first parameter value and the second parameter value, so the description of the present application is not repeated.
Fig. 6 is a functional block diagram of an error compensation device according to an embodiment of the present application. The error compensation device 11 includes a selection unit 110, an acquisition unit 111, a measurement unit 112, a calculation unit 113, a determination unit 114, a control unit 115, and a compensation unit 116. The module/unit referred to herein refers to a series of computer readable instructions capable of being fetched by the controller 102 of fig. 7 and performing a fixed function, which are stored in the memory 101 of fig. 7. In the present embodiment, the functions of the respective modules/units will be described in detail in the following embodiments.
The selecting unit 110 is configured to select any plane of the detection tool as a plane to be compensated.
And an obtaining unit 111, configured to obtain a first rotation angle and a second rotation angle of the plane to be compensated, where the first rotation angle corresponds to a first rotation axis of the five-axis machine tool, and the second rotation angle corresponds to a second rotation axis of the five-axis machine tool.
And the measuring unit 112 is configured to measure a center coordinate of a center point in a hole of the plane to be compensated if the plane to be compensated is an open plane, and calculate an intersection coordinate of an intersection point between a central axis of the hole and the plane to be compensated according to the depth of the hole and the center coordinate.
And a calculating unit 113, configured to calculate a projection distance between the intersection point and each reference plane according to the intersection coordinate and a plane equation of each reference plane.
A determining unit 114 for determining initial coordinates of the intersection point based on the plurality of projection distances.
And a control unit 115, configured to control the first rotation axis to rotate through the first rotation angle, and control the second rotation axis to rotate through the second rotation angle, so that the plane to be compensated rotates.
The measuring unit 112 is further configured to measure coordinates of a plurality of points on the plane to be compensated after rotation.
A calculating unit 113, configured to calculate a normal vector of the rotated plane to be compensated according to coordinates of the plurality of points;
The calculating unit 113 is further configured to calculate a first error angle of the plane to be compensated corresponding to the first rotation axis and a second error angle of the plane to be compensated corresponding to the second rotation axis based on a preset vector, the first rotation angle, the second rotation angle, and the normal vector.
The control unit 115 is further configured to control the first rotation axis to rotate through the first error angle, and control the second rotation axis to rotate through the second error angle, so that the rotated plane to be compensated rotates as a horizontal plane.
The calculating unit 113 is further configured to calculate a standard coordinate of the intersection point on the horizontal plane according to the initial coordinate of the intersection point, the first error angle, and the second error angle.
The measuring unit 112 is further configured to measure the actual coordinates of the intersection point on the horizontal plane.
The calculating unit 113 is further configured to calculate a position error value corresponding to the hole according to the standard coordinate and the actual coordinate;
The compensation unit 116 is further configured to compensate the absolute coordinate system of the detection fixture based on the position error value.
In some embodiments of the application, in addition to the five machine axes above, the five-axis machine tool includes a numerical control system (Numerical Control System), wherein the numerical control system in the five-axis machine tool may be a computer control system (Computerized Numerical Control, CNC). For example, as shown in fig. 7, a schematic structural diagram of a numerical control system of a five-axis machine tool according to an embodiment of the present application is shown. The numerical control system 10 in fig. 7 may include a memory 101, a controller 102, a driver 103, a motor 104, and a sensor 105.
Memory 101 may include one or more random access memories (random access memory, RAM) and one or more non-volatile memories (NVM). The random access memory may be directly readable and writable by the controller 102, may be used to store executable programs (e.g., machine instructions) such as programs that are running, may also be used to store user and application data, and the like. The random access memory may include a static random-access memory (SRAM), a dynamic random-access memory (dynamic random access memory, DRAM), a synchronous dynamic random-access memory (synchronous dynamic random access memory, SDRAM), a double data rate synchronous dynamic random-access memory (double data rate synchronous dynamic random access memory, DDR SDRAM), and the like.
The nonvolatile memory may store executable programs, store data of users and applications, and the like, and may be loaded into the random access memory in advance for the controller 102 to directly read and write. The nonvolatile memory may include a disk storage device, a flash memory (flash memory).
The memory 101 is used to store one or more computer programs. One or more computer programs are configured to be executed by the controller 102. The one or more computer programs include a plurality of instructions that when executed by the controller 102 implement the error compensation method performed on the numerical control system 10.
Controller 102 is a control center of numerical control system 10, and controller 102 may include a numerical control controller and a programmable logic controller (Programmable Logic Controller, PLC). The numerical control controller is a main control device of the numerical control system and is used for receiving or generating processing instructions and converting the processing instructions into electric signals to control each driving system so as to realize the movement and processing operation of the machine tool. The programmable logic controller is a digital computer specially used for automatic control, performs operation and decision through a preset logic program, and controls different actions and technological processes of the machine tool according to input signals (such as sensor signals) and current state judgment conditions. For example, during a tool change, the programmable logic controller may monitor the tool position signal and execute a corresponding tool change program.
And a driver 103 for driving the motors in each axial direction to perform accurate position control according to the command sent by the control center. The driver is in communication with the controller 102, and receives the position command from the controller 102 and converts the receiving end command into a current or voltage signal to drive the motor to perform accurate position control, so that the multi-axis linkage control of the five-axis machine tool is realized.
The motor 104 converts electrical energy to mechanical energy via a screw drive on a rotating shaft, driving the workpiece or tool in linear or rotational motion in different machining axes. Therefore, the multi-axis linkage motion of the five-axis machine tool can be realized, and the machining axis of the five-axis machine tool can complete complex machining operation. In addition, the motor 104 cooperates with sensors such as encoders to sense the position information of each machining shaft in real time and feed the position information back to the controller 102. In addition, the motor 104 can receive mass from the controller 102, start and stop quickly according to the received instructions, and can perform smooth acceleration and deceleration control as needed. Thus being beneficial to avoiding the impact and vibration in the processing process of the workpiece and improving the surface quality and the processing precision of the workpiece.
The sensor 105 is used to monitor the actual position information of each process and feed back the actual position information to the controller 102, so that the numerical control system performs position control on the motor 104. The sensors 105 include, but are not limited to: encoder, grating scale, etc. In addition, the sensor 105 may be used to monitor the temperature of various parts of the machine tool, including the motor 104, spindle, detection tool, workpiece, etc., in order to maintain the operating temperature of the machine tool within a suitable operating temperature range and to avoid machining errors due to temperature variations.
It should be understood that the illustrated structure of the present embodiment does not constitute a particular limitation of the digital control system 10. In other embodiments of the present application, the numerical control system 10 may include more or less components than illustrated, or certain components may be combined, or certain components may be split, or different arrangements of components. The illustrated components may be implemented in hardware, software, or a combination of software and hardware.
Embodiments of the present application further provide a computer readable storage medium, where a computer program is stored, where the computer program includes program instructions, and a method implemented when the program instructions are executed may refer to a method in each of the foregoing embodiments of the present application.
The computer readable storage medium may be an internal memory of the numerical control system according to the above embodiment, for example, a hard disk or a memory of the numerical control system. The computer readable storage medium may also be an external storage device of the numerical control system, such as a plug-in hard disk, a smart memory card (SMART MEDIA CARD, SMC), a Secure Digital (SD) card, a flash memory card (FLASH CARD) or the like, which are provided on the numerical control system.
In some embodiments, the computer readable storage medium may include a storage program area and a storage data area, wherein the storage program area may store an operating system, an application program required for at least one function, and the like; the storage data area may store data created according to the use of the numerical control system, and the like.
In the foregoing embodiments, the descriptions of the embodiments are emphasized, and in part, not described or illustrated in any particular embodiment, reference is made to the related descriptions of other embodiments.
Those of ordinary skill in the art will appreciate that the various illustrative elements and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, or combinations of computer software and electronic hardware. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the solution. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present application.
The above embodiments are only for illustrating the technical solution of the present application, and are not limiting; although the application has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present application, and are intended to be included in the scope of the present application.

Claims (10)

1. An error compensation method applied to a five-axis machine tool, wherein a surface of the five-axis machine tool is provided with a detection jig with corrected reference surfaces, a plane of the detection jig comprises a plurality of reference surfaces parallel to a coordinate axis plane of a machine tool coordinate system of the five-axis machine tool, and each reference surface is parallel to one coordinate axis plane, and the method comprises:
Selecting any plane of the detection jig as a plane to be compensated, and acquiring a first rotation angle and a second rotation angle of the plane to be compensated, wherein the first rotation angle corresponds to a first rotation shaft of the five-axis machine tool, and the second rotation angle corresponds to a second rotation shaft of the five-axis machine tool;
If the plane to be compensated is an open plane, measuring the center coordinates of a center point in a hole of the plane to be compensated, and calculating the intersection coordinates of an intersection point between the central axis of the hole and the plane to be compensated according to the depth of the hole and the center coordinates;
calculating the projection distance between the intersection point and each datum plane according to the intersection coordinates and a plane equation of each datum plane, and determining the initial coordinates of the intersection point according to a plurality of projection distances;
The first rotating shaft is controlled to rotate through the first rotating angle, and the second rotating shaft is controlled to rotate through the second rotating angle, so that the plane to be compensated rotates;
Measuring coordinates of a plurality of points on the rotated plane to be compensated, and calculating normal vectors of the rotated plane to be compensated according to the coordinates of the plurality of points;
calculating a first error angle of the plane to be compensated corresponding to the first rotating shaft and a second error angle of the plane to be compensated corresponding to the second rotating shaft based on a preset vector, the first rotating angle, the second rotating angle and the normal vector;
the first rotating shaft is controlled to rotate through the first error angle, and the second rotating shaft is controlled to rotate through the second error angle, so that the rotated plane to be compensated rotates to be a horizontal plane;
Calculating standard coordinates of the intersection point on the horizontal plane according to the initial coordinates of the intersection point, the first error angle and the second error angle;
measuring the actual coordinates of the intersection points on the horizontal plane, and calculating the position error value corresponding to the hole according to the standard coordinates and the actual coordinates;
And compensating an absolute coordinate system of the detection jig based on the position error value.
2. The error compensation method of claim 1, wherein the detection jig is mounted on a disk surface of the second rotation shaft, and a center of the detection jig is located on a rotation center of the second rotation shaft.
3. The error compensation method of claim 1, wherein the calculating a first error angle of the plane to be compensated corresponding to the first rotation axis and a second error angle of the plane to be compensated corresponding to the second rotation axis based on a preset vector, the first rotation angle, the second rotation angle, and the normal vector comprises:
Constructing a rotation matrix according to the first rotation angle, a first parameter corresponding to the first error angle and a second parameter corresponding to the second error angle;
Establishing a parameter equation according to the preset vector, the rotation matrix and the normal vector;
Solving the parameter equation to obtain a first parameter value of the first parameter and a second parameter value of the second parameter;
calculating an updated first rotation angle according to the first parameter value and the first rotation angle;
the first error angle and the second error angle are calculated based on the preset vector, the updated first rotation angle, the second rotation angle, and the normal vector.
4. The error compensation method of claim 3, wherein the rotation matrix is expressed as:
Wherein denotes the rotation matrix,/> denotes the first rotation angle, θ A denotes the first parameter, and θ C denotes the second parameter.
5. The error compensation method of claim 3, wherein the parameter equation is expressed as:
Wherein denotes the rotation matrix,/> denotes the normal vector, and/> denotes the preset vector.
6. The error compensation method of claim 1, wherein the method of calculating the standard coordinates comprises:
Wherein P 1 'represents the standard coordinate, a represents the first error angle, X' represents the abscissa in the initial coordinate, Y 'represents the ordinate in the initial coordinate, Z' represents the ordinate in the initial coordinate, and c represents the second error angle.
7. The method of claim 1, wherein calculating the position error value corresponding to the hole according to the standard coordinates and the actual coordinates comprises:
And determining a difference value between the standard coordinates and the actual coordinates as the position degree error value.
8. The error compensation method according to claim 1 or 7, wherein compensating the absolute coordinate system of the detection jig based on the position error value comprises:
And adjusting the origin of the absolute coordinate system according to the position error value.
9. The error compensation method according to claim 1, wherein the controlling the first rotation axis to rotate by the first rotation angle and the controlling the second rotation axis to rotate by the second rotation angle includes:
generating a numerical control instruction according to the first rotation angle and the second rotation angle, and controlling the first rotation shaft and the second rotation shaft to rotate by executing the numerical control instruction, so that the plane to be compensated rotates.
10. A five-axis machine tool, characterized in that it comprises:
A memory storing at least one instruction; and
A controller executing the at least one instruction to implement the error compensation method of any one of claims 1 to 9.
CN202410063745.6A 2024-01-16 2024-01-16 Error compensation method and five-axis machine tool Pending CN117884949A (en)

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CN202410063745.6A CN117884949A (en) 2024-01-16 2024-01-16 Error compensation method and five-axis machine tool

Applications Claiming Priority (1)

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