CN111895905B - Error compensation method for hexagonal axis straightness detection system - Google Patents

Error compensation method for hexagonal axis straightness detection system Download PDF

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CN111895905B
CN111895905B CN202010459808.1A CN202010459808A CN111895905B CN 111895905 B CN111895905 B CN 111895905B CN 202010459808 A CN202010459808 A CN 202010459808A CN 111895905 B CN111895905 B CN 111895905B
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error
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CN111895905A (en
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周娟
黄宇杭
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China Jiliang University
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B21/00—Measuring arrangements or details thereof, where the measuring technique is not covered by the other groups of this subclass, unspecified or not relevant
    • G01B21/02—Measuring arrangements or details thereof, where the measuring technique is not covered by the other groups of this subclass, unspecified or not relevant for measuring length, width, or thickness
    • G01B21/04—Measuring arrangements or details thereof, where the measuring technique is not covered by the other groups of this subclass, unspecified or not relevant for measuring length, width, or thickness by measuring coordinates of points
    • G01B21/045—Correction of measurements
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B7/00—Measuring arrangements characterised by the use of electric or magnetic techniques
    • G01B7/30—Measuring arrangements characterised by the use of electric or magnetic techniques for measuring angles or tapers; for testing the alignment of axes
    • G01B7/31—Measuring arrangements characterised by the use of electric or magnetic techniques for measuring angles or tapers; for testing the alignment of axes for testing the alignment of axes

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Abstract

The invention discloses a pneumatic three-jaw chuck eccentricity error compensation method for a hexagonal axis straightness detection system. Aiming at the rotation error generated by the eccentricity of a pneumatic three-jaw chuck in a hexagonal axis straightness detection system, the method comprises two stages of measurement and compensation; acquiring offsets in the directions of the three groups of opposite surfaces by adopting a hexagonal axis opposite surface subtraction principle; in the process of measuring the rotation error, the deflection error generated by the bending of the shaft per se is taken into consideration by the system, and is used as the measurement quantity in the rotation error compensation equation for correction, so that an error compensation model is constructed.

Description

Error compensation method for hexagonal axis straightness detection system
Technical Field
The invention relates to the technical field of straightness measurement, in particular to an error compensation method for a hexagonal axis straightness detection system.
Background
The pneumatic three-jaw chuck is a mechanical device for positioning and clamping a workpiece by utilizing radial movement of movable clamping jaws uniformly distributed on a chuck body, and comprises a chuck, the movable clamping jaws, an air pressure gyrator, an electric control part and other connecting components. The workpiece is clamped by the pneumatic three-jaw chuck, the mounting process is simple, convenient and labor-saving, automatic centering can be realized, and the clamping force is stable and adjustable. With the changing market demand, the automatic centering precision requirement of some high-precision equipment on the pneumatic three-jaw chuck is relatively increased. However, in actual measurement, factors such as the surface structure of the clamped workpiece, the rotating speed of the driving motor and the like cause the intersection point of the action lines of the three movable clamping jaws to deviate, namely, the clamping center point deviates from the ideal center point, so that a rotation error is generated. Therefore, the compensation of the rotation error of the pneumatic three-grab chuck is an important factor for improving the measurement accuracy of the straightness of the hexagonal axis.
Error compensation is an important part of instrument design and machining. For the rotation error of the shaft, a common error compensation method is to analyze error sources and analyze the influence form of each error on a measurement result; secondly, error correction is obtained in a certain mode, a corresponding mathematical model is established, error difference is eliminated from the measured data, and the purpose of improving the measurement precision is achieved. The method is mainly applied to the field of error measurement such as roundness, cylindricity and rotation error of a circular shaft, a sensor is placed at different positions by adopting a reverse method, repeated measurement is carried out on the same to-be-measured value simultaneously or sequentially, error correction quantity is solved according to a built mathematical model by utilizing a determined position relation and the same or known measurement conditions according to multiple measurement results, and error compensation is carried out on measurement data. However, as the position of the sensor changes, multiple or multiple measurements are required, which increases computational and measurement complexity and is not suitable for real-time compensation in dynamic models. Most of the traditional methods are based on a round axis to obtain error correction, and the prior researches lack the measurement and error compensation of rotation errors of an axis with irregular surface. Therefore, how to provide a method for compensating the eccentricity error of the pneumatic three-jaw chuck for a six-axis linearity detection system becomes a problem to be solved by those skilled in the art.
Disclosure of Invention
In view of the above problems, the invention provides an eccentric error compensation method for a pneumatic three-jaw chuck of a hexagonal axis straightness detection system, which compensates a gyration error caused by eccentricity of the pneumatic three-jaw chuck in a process of measuring the hexagonal axis straightness, can detect and compensate offset errors of each measuring point in three groups of opposite surface directions in real time by adopting a hexagonal axis opposite surface subtraction method, can eliminate the influence of deflection errors by utilizing a reverse method of rotating the hexagonal axis, improves the compensation accuracy of an error compensation model, and can improve the measurement accuracy of the hexagonal axis straightness.
The invention provides an error compensation method for a hexagonal axis straightness detection system in a first aspect, which comprises the following steps:
(1) selecting a calibration hexagonal shaft with the length of S, and loading the calibration hexagonal shaft to the hexagonal shaft straightness detection system;
(2) measuring at an actual measuring point C which is on the calibrated hexagonal shaft and has a distance of m with the left pneumatic three-jaw chuck to obtain the offset (C) in the direction of three groups of opposite surfaces of the calibrated hexagonal shaftα，Cβ，Cγ) And converted into the axis vector coordinate (x) of the point Cc,yc) (ii) a Defining an ideal measuring point of the calibrated hexagonal axis when the deflection error of the point C is 0 as C ', and setting the axis vector coordinate of the ideal measuring point C ' as (x 'c,y'c) The deflection error of point C relative to point C' is (Δ x)c,Δyc) Then there is (x)c,yc)＝(x'c+Δxc,y'c+Δyc)；
Measuring an actual measurement point D with the distance of m between the calibration hexagonal shaft and the pneumatic three-jaw chuck on the right side to obtain an axis vector seat of the point DLabel (x)d,yd) (ii) a Defining the ideal measuring point of the calibrated hexagonal axis when the deflection error of the point D is 0 as D ', and setting the axis vector coordinate of the ideal measuring point D ' as (x 'd,y'd) The deflection error of point D relative to point D' is (Δ x)d,Δyd) Then there is (x)d,yd)＝(x'd+Δxd,y'd+Δyd)；
(3) Detaching the calibrated hexagonal shaft from the hexagonal shaft straightness detection system, rotating the calibrated hexagonal shaft by 180 degrees, and reloading the calibrated hexagonal shaft straightness detection system;
(4) measuring the point C rotated by 180 degrees to obtain the axis vector coordinate (x) of the actual measurement point C'c,y"c) Then there is (x) "c,y"c)＝(x'c-Δxc,y'c-Δyc)；
Measuring the D point rotated by 180 degrees to obtain the axis vector coordinate (x) of the actual measurement point D'd,y"d) Then there is (x) "d,y"d)＝(x'd-Δxd,y'd-Δyd)；
(5) Obtaining coordinates of ideal measuring points C ' and D ' from (2), (3) and (4), wherein the coordinates of the point C ' are:
Figure BDA0002510548570000021
and the coordinates of point D' are:
Figure BDA0002510548570000022
(6) according to the coordinates of the ideal measuring points C 'and D', determining a space straight line equation connecting C 'and D' as follows:
Figure BDA0002510548570000023
the ideal clamping point a ' of the left pneumatic three-jaw chuck on the calibrated hexagonal axis when the deflection error is 0 and the ideal clamping point B ' of the right pneumatic three-jaw chuck on the calibrated hexagonal axis are also on the spatial straight line, wherein the coordinates of the point a ' are as follows:
Figure BDA0002510548570000024
and the coordinates of point B' are:
Figure BDA0002510548570000025
(7) substituting the Z-axis coordinate of any point N to be measured between the point A 'and the point B' into the space straight line equation to obtain the coordinate (X) of the point Nn,Yn) And converting it into a rotation error offset (N) in the direction of each opposite surface of the calibrated hexagonal axisα，Nβ，Nγ)；
(8) Unloading the calibrated hexagonal shaft, loading the hexagonal shaft to be measured into the hexagonal shaft linearity detection system, and regarding any point P to be measured on the hexagonal shaft linearity detection system, detecting the offset (P ') of the detected point P in the direction of each opposite surface of the hexagonal shaft to be measured'α，P′β，P′γ) Subtracting the amount of slewing error offset (P) calculated from (7)α，Pβ， Pγ) The result is the measurement result after error compensation;
(9) a plurality of points are taken on the hexagonal axis to be detected for detection, and the coordinates (x) of the plurality of points are obtained after error compensation and conversion are carried out according to the step (8)j,yj) N, · j ═ 1, 2; and calculating corresponding straightness errors by obtaining the fitting of a reference axis and a shaft curve, thereby determining the maximum deflection position required by the straightening work of the shaft and the axial position corresponding to the measuring point of the maximum deflection position.
Furthermore, selecting an available hexagonal shaft with the best straightness as a calibration shaft, sequentially marking six outer surfaces of the calibration shaft according to the sequence of the labels 1-6, respectively arranging a capacitive grating micrometer at a position m away from the pneumatic three-jaw chucks at two ends, marking a left-side micrometer as L, marking a right-side micrometer as R, and equidistantly distributing the rest capacitive grating micrometers in the middle of L, R; controlling the pneumatic three-jaw chucks at the two ends to clamp and calibrate the hexagonal shaft, marking the upward surface of the calibrated hexagonal shaft as U before the computer starts to test, and marking the upward surface of the pneumatic three-jaw chuck at the two ends as U; the pneumatic three-jaw chuck clamps the calibration hexagonal shaft to rotate for a circle for measurement; when the pneumatic three-jaw chuck clamps the calibrated hexagonal shaft to rotate for one circle for measuring deflection, the surface of the pneumatic three-jaw chuck structure marked as U and facing upwards is required to be kept consistent in the front and back rotating directions.
Furthermore, the calculation method for converting the offset in the direction of each opposite surface of the calibrated hexagonal axis into the axis vector coordinate is as follows:
Figure BDA0002510548570000031
wherein i is a reference number of six outer surfaces of the hexagonal axis, i is 1,2,3, δ i, i +3 is an offset of a group of the hexagonal axis relative to the outer surfaces i and i +3, δ a, δ b, δ c are offsets described in claim 1, that is, δ i, i +3 is offset on three groups of opposite surfaces on an abc three-axis coordinate system, Φ is an axis vector in a rectangular coordinate system, and an included angle between an axis vector θ and the x axis.
Further, the reference axis is calculated by:
Figure BDA0002510548570000032
wherein N is the number of the measuring points, (x)j,yj) (j ═ 1,2,. N) are the coordinates of the N measurement points.
Further, the axis curve fitting is calculated by:
y(x)＝β0+β1x+β2x2·+βnxn
Figure BDA0002510548570000041
Figure BDA0002510548570000042
the invention provides a hexagonal axis straightness detection system which comprises a pneumatic three-jaw chuck for clamping a hexagonal axis, a motor for driving the pneumatic three-jaw chuck to rotate through a synchronous belt wheel, a capacitive micrometer indirectly contacted with the hexagonal axis, a chuck with six clamping grooves and a proximity switch, wherein when the clamping grooves are close to the proximity switch, the capacitive micrometer receives detection signals to read and is also close to the proximity switch
And transmitting data so as to realize rotation detection of the straightness of the hexagonal axis.
The technical scheme provided by the invention has the beneficial effects that:
(1) aiming at the process of detecting the straightness of the hexagonal axis, the error influence generated by indirect contact between the capacitive grating micrometer and the hexagonal axis can be eliminated by adopting the opposite surface subtraction method, the offset of each measuring point of the hexagonal axis in the directions of the three groups of opposite surfaces can be detected in real time, and the offset is subjected to real-time error compensation.
(2) Aiming at the problem of eccentricity of the pneumatic three-jaw chuck, the traditional error compensation method only compensates the rotation error at the position of the movable clamping jaw, and the method utilizes a reverse method to eliminate the influence of deflection error generated by self bending of the shaft, thereby improving the compensation precision of an error compensation model and improving the measurement precision of the straightness of the hexagonal shaft.
(3) The traditional reversal method eliminates the deflection error influence of the circular shaft by changing the position of the sensor, and the reversal method provided by the invention adopts the position of the manual rotating shaft to perform rotation detection on the hexagonal shaft with an irregular surface, so that the operation is simple, the realization is easy, and the deflection error influence can be eliminated.
(4) The invention utilizes the existing hexagonal axis straightening machine equipment to carry out rotation error compensation on the non-full-circle pneumatic three-jaw chuck, is beneficial to subsequent evaluation of the straightness error of the hexagonal axis and the straightening work of the axis, and is convenient for practical engineering application.
The conception, the specific structure and the technical effects of the present invention will be further described with reference to the accompanying drawings to fully understand the objects, the features and the effects of the present invention.
Drawings
FIG. 1 is a schematic view of a pneumatic three-jaw chuck clamping hexagonal shaft mechanical structure in the process of measuring straightness according to the present invention;
FIG. 2 is a schematic diagram illustrating the principle of detecting the straightness of the hexagonal axis according to the present invention;
FIG. 3 is a schematic illustration of a hexagonal axis cross-sectional offset provided by the present invention;
FIG. 4 is a schematic view of a rotation error analysis provided by the present invention;
FIG. 5 is a schematic diagram of the reverse method for eliminating deflection error analysis provided by the present invention;
FIG. 6 is a schematic diagram of the measurement and evaluation process analysis of the hexagonal straightness error provided by the present invention.
In the figure: 1. the device comprises a hexagonal shaft, 2 a movable clamping jaw, 3 a pneumatic three-jaw chuck, 4 a rotary driving motor, 5 a rotary chuck, 6 a capacitive grid micrometer measuring head, 7 and a capacitive grid micrometer.
Detailed Description
The technical contents of the preferred embodiments of the present invention will be more clearly and easily understood by referring to the drawings attached to the specification. The present invention may be embodied in many different forms of embodiments and the scope of the invention is not limited to the embodiments set forth herein.
The invention provides a pneumatic three-jaw chuck eccentricity error compensation method for a hexagonal axis straightness detection system. Aiming at the rotation error generated by the eccentricity of a pneumatic three-jaw chuck in a hexagonal axis straightness detection system, the method comprises two stages of measurement and compensation; acquiring offsets in the directions of the three groups of opposite surfaces by adopting a hexagonal axis opposite surface subtraction principle; in the process of measuring the rotation error, the deflection error generated by the bending of the shaft per se is taken into consideration by the system, and is used as the measurement quantity in the rotation error compensation equation for correction, so that an error compensation model is constructed.
Firstly, the scheme adopts the opposite face subtraction method, so that the error influence caused by the indirect contact between the capacitance-grid micrometer and the hexagonal shaft can be eliminated, the offset of each measuring point of the hexagonal shaft in the directions of three groups of opposite faces can be detected in real time, and real-time error compensation is carried out. And secondly, the influence of deflection errors can be eliminated by utilizing an inverse method for rotating the hexagonal shaft, the compensation precision of an error compensation model is improved, and the straightness measurement precision of the hexagonal shaft is improved. In addition, the existing hexagonal axis straightener equipment is applied to compensate the rotation error of the non-full-circle pneumatic three-jaw chuck, and the practical engineering application is facilitated.
The following describes the specific implementation process of the present invention in detail, including the following steps:
step 1, designing a linearity detection experiment aiming at a calibrated hexagonal shaft, collecting offsets delta of actual measurement points close to the positions of pneumatic three-jaw chucks at two ends on three groups of opposite surfaces of the hexagonal shaft, and synthesizing an axis vector (x, y) under a rectangular coordinate system through coordinate conversion for calculating a space coordinate of the subsequent measurement point.
According to one embodiment of the invention, before a hexagonal-axis straightness detection experiment is designed, a plurality of hexagonal axes are obtained from a production site and compared, one hexagonal axis with better straightness is selected as a calibration axis, and if the total length is S, six outer surfaces are sequentially marked according to the sequence of the labels 1-6; and (3) respectively arranging a capacitive grid micrometer at a position 50mm away from the pneumatic three-jaw chucks at the two ends, marking the left-side micrometer as L, marking the right-side micrometer as R, equidistantly distributing the rest capacitive grid micrometers in the middle of L, R, marking the upward surface of the hexagonal shaft as U, and marking the upward surface of the pneumatic three-jaw chuck at the two ends as U. When the pneumatic three-jaw chuck clamps the hexagonal shaft to rotate for one circle for deflection measurement, the surface of the pneumatic three-jaw chuck structure marked as U and facing upwards is required to be kept consistent in the front and back directions of rotation.
As shown in fig. 1, in actual measurement, the pneumatic three-jaw chuck 3 is controlled to enable the movable clamping jaw 2 to clamp the hexagonal shaft 1, after the movable clamping jaw is stabilized, the rotary driving motor 4 is controlled to drive the pneumatic three-jaw chuck 3 to rotate through a synchronous belt pulley fixed with the main shaft, and the capacitive micrometer 7 is indirectly contacted with the hexagonal shaft 1; the chuck 5 is provided with 6 clamping grooves, and when the clamping grooves pass through the proximity switch, the capacitive grating micrometer 7 receives detection signals to read and transmit data, so that the rotation detection of the straightness of the hexagonal axis is realized.
The mutual positional relationship before and after the hexagonal axis is rotated by 180 ° is shown in fig. 2, and a zy coordinate system is established with the axial direction and the deflection direction as references. The measured six external surface capacitance grating micrometering values are { V1, V2, V3, V4, V5, V6}, and analysis is carried out by taking a group of opposite surface data { V1, V4} as an example, and the calculation mode is as follows:
Figure BDA0002510548570000061
where M is the distance from zero of the capacitance-grid micrometer to the z-axis, δ1,4The offset of a certain measuring point of the hexagonal axis on the opposite surfaces 1 and 4 is shown, and r is half of the distance between the two opposite surfaces.
The process of synthesizing the axis vector by the offset in the present invention is described in detail with reference to fig. 3.
The offset and the axis vector can be mutually converted, and when x and y of the axis vector P at the section of the measuring point are obtained, the offset delta can be converted into an abc three-axis coordinate system according to the geometric relationshipa、δb、δcAs shown in FIG. 3 (a); when obtaining the offset δ on three sets of opposite facesa、δb、δcAlternatively, the x and y coordinates may be converted to an xy rectangular coordinate system, as shown in fig. 3 (b).
And converting the coordinates of the three output groups of offset into an axis vector. The point O represents the origin of coordinates, which represents the ideal axial center point, and the point P represents the actual center of the curved cross-section, two coordinate systems are established, one is an xy rectangular coordinate system, the other is an abc three-axis coordinate system established with reference to three sets of opposite surfaces of the ideal hexagonal axial cross-section, and the y-axis and the a-axis of the two coordinate systems coincide, as shown in fig. 3 (b). According to the geometrical relationship, the following are included in the rectangular coordinate system:
Figure BDA0002510548570000062
transformed by a generalized inverse matrix:
Figure BDA0002510548570000063
wherein, the axial center P can be (x, y) and (delta) respectivelya,δb,δc) Two sets of coordinates represent the distance from the axis P to the ideal axis point O
Figure BDA0002510548570000064
The angle of the vector with the positive x-axis direction is represented by θ, as shown in fig. 3 (b).
Step 2, analyzing the cross section where the measuring point is located, when the deflection error does not exist in the hexagonal axis, defining a space vector (x ', y') and a deflection error vector (delta x, delta y) of the ideal measuring point, and calculating a space vector (x '+ delta x, y' + delta y) of the actual measuring point; and eliminating the influence of the self-deflection error of the shaft by utilizing a reverse method and a geometric relation, and calculating the coordinate value of the space vector of the ideal measuring point.
The process for eliminating the influence of the deflection error by using the reverse method provided by the invention is described in detail by combining fig. 4 and fig. 5.
According to the hexagonal straightness detection experiment designed in the step 1, the actual measurement point at the left micrometer L is assumed to be C, the ideal measurement point is assumed to be C ', the actual measurement point at the right micrometer R is assumed to be D, and the ideal measurement points are D', A, A ', B and B' and are distributed at the movable clamping jaw; the dotted line AB is the rotation center line when the movable clamping jaws at the two ends clamp the hexagonal shaft and is parallel to the z-axis, the spatial straight line a 'B' is the clamping center line of the movable clamping jaws at the two ends, and the curve a 'B' is the actual shape center line of the hexagonal shaft, i.e., the deflection error caused by the bending of the shaft itself exists, as shown in fig. 4. In order to show the intuitiveness of eliminating deflection errors by a reverse method, a rotation center line AB is placed above a z axis; in order to facilitate the subsequent geometric analysis of the measuring points, the rotation center line AB is coincided with the z axis, the coordinates of each measuring point on the x axis and the y axis of the space coordinate system are 0, and the coordinate on the z axis is defined as the position of the set capacitance grid micrometer.
In this embodiment, for the inverse method provided by the present invention, taking the analysis of the cross section of the actual measurement point C as an example, and because the analysis is that the cross section of the measurement point C is located, the coordinate on the z axis is equal, so the x axis coordinate and the y axis coordinate are discussed first, the z axis coordinate is discussed during the subsequent space straight line fitting, and the right actual measurement point D can be obtained similarly, including the following steps:
(1) analyzing the section of the actual measurement point C, wherein the end point A is coincident with the origin of coordinates O, and when the deflection error is generated due to the bending of the shaft, the actual measurement result is
Figure BDA0002510548570000071
A vector; when the shaft has no bending, the deflection error is zero, and the measuring point is an ideal measuring point C
Figure BDA0002510548570000072
As a deflection vector for the left side measurement point, assume C '(x'C, y′C)，
Figure BDA0002510548570000073
The actual measurement point C coordinate is ((x'C+ΔxC,y′C+ΔyC) As shown in fig. 5 (a);
(2) after completing the first rotation detection of the straightness accuracy according to the experiment designed in the step 1 and recording the axial vector data of the measuring points at two sides, stopping the detection, keeping the pneumatic three-jaw chucks at two ends still, controlling the movable clamping jaws to dismount the hexagonal shaft, manually rotating 180 degrees, and paying attention to that the outer surface of the hexagonal shaft marked as U faces downwards at the moment;
(3) the actual measurement point C is changed into C' after being rotated by 180 DEG, and the deflection vector is changed at the moment
Figure BDA0002510548570000074
Become into
Figure BDA0002510548570000075
Performing a second rotation detection experiment of straightness, recording data, and recording
Figure BDA0002510548570000076
Then the C "coordinate is (x'c'-Δxc，y'c'-Δyc) As shown in fig. 5 (b);
(4) the coordinates of the ideal measuring point C' can be obtained according to the geometric relationship
Figure BDA0002510548570000077
(5) The coordinates of the ideal right measuring point D' obtained by the same method are
Figure BDA0002510548570000078
The steps are used for analyzing the cross section where the actual measuring point is located to obtain the space coordinate of the ideal measuring point, and the purpose is to describe the process of eliminating the influence of the self-deflection error of the shaft by a reverse method in detail. According to the hexagonal axis straightness detection experiment designed in the step 1, the offset of C, C 'and D, D' points on three opposite surfaces can be directly obtained, and the space coordinates of ideal measuring points C 'and D' can be obtained by synthesizing axis vectors through coordinate conversion.
And 3, determining a space straight line according to the space vector of the ideal measuring point, and collecting the space vector and the rotation error vector which are positioned at the positions of the pneumatic three-jaw chucks at the two ends on the space straight line.
Determining a space straight line according to the space coordinates of the ideal measuring points C 'and D' obtained in the step 2, wherein the calculation mode is as follows:
Figure BDA0002510548570000081
wherein, A ' and B ' are also on the space straight line, and the coordinate of the point A ' is known as:
Figure BDA0002510548570000082
the coordinates of the B' point are:
Figure BDA0002510548570000083
the rotation error vector at the movable clamping jaw can be obtained according to the space coordinates of A' and B
Figure BDA0002510548570000084
Figure BDA0002510548570000085
And 4, collecting the positions z of the capacitance grid micrometer at other actual measurement points, substituting the positions z into a space linear equation, calculating the (x, y) of each actual measurement point, and converting the coordinates into the offset delta 'of each measurement point on three opposite surfaces under a three-axis coordinate system, wherein the offset delta' is used as the offset generated by the rotation error at the measurement points.
In the step, six capacitance grid micrometers are equidistantly arranged between the capacitance grid micrometers L and R, and the position of the jth capacitance grid micrometer is marked as zj(j ═ 1,2.. 6), namely the z-axis coordinate of the measuring point in the space coordinate system, and the z-axis coordinate is substituted into the space linear equation to obtain the j-th measuring point in z ═ zj(j ═ 1,2,. 6) coordinates x at the section planej、yjThen x is addedj、yjObtaining the offset delta on the three groups of opposite surfaces according to the coordinate conversion direction described in the step 1 and the conversion of the abc three-axis coordinate systema′j、δb′j、δc′jAnd accordingly, the offset is used as the rotary error offset generated at the jth measuring point due to the rotary error of the pneumatic three-jaw chuck.
And 5, designing a straightness detection experiment aiming at the common hexagonal axis, collecting the offset delta of each actual measurement point on three groups of opposite surfaces, subtracting the offset delta ' generated due to rotation error, and carrying out coordinate conversion to synthesize an axis vector (delta x ', delta y ') under a rectangular coordinate system, namely the space vector of each measurement point after compensation of rotation error.
After the rotation error is measured and data is recorded according to the step 4, stopping detection, dismounting the calibration shaft, selecting other common hexagonal shafts to perform a linearity detection experiment, and obtaining the offset delta of the jth measuring point on the three groups of opposite surfacesaj、δbj、δcjIn this case, j is 1,2.. and 8, and the rotation error offset obtained in step 4 is subtracted, and the calculation method is as follows:
Figure BDA0002510548570000086
wherein, Delta deltaaj、Δδbj、ΔδcjCompensating the offset on the three sets of opposing surfaces after the rotation error for the jth measurement point can be converted into z ═ z for the jth measurement pointj(j ═ 1,2,. 8) axis vector coordinates (Δ x 'in cross section'j, Δy′j)。
And 6, during actual measurement, subtracting the value of the rotation error offset as the output of the error compensation model, namely the output of the error-compensated capacitance grid micrometer.
Obtaining eight measurement point space coordinates (delta x ') after compensation of rotation errors according to the step 5'j,Δy′j,zj) And (j ═ 1,2.., 8), and the output is used as the output of the error-compensated capacitance grid micrometer, so that the linearity of the common hexagonal axis can be reflected by performing space curve fitting subsequently.
And 7, acquiring output data of the plurality of capacitive grating micrometers, and calculating corresponding straightness errors by obtaining a reference axis and axis curve fitting for facilitating subsequent evaluation of the straightness errors of the hexagonal axis and alignment of the axis, so as to determine the maximum deflection position required by the alignment work of the axis and the axial position corresponding to the measuring point of the maximum deflection position.
The measurement and evaluation process of the straightness error of the hexagonal axis in the invention is described in detail with reference to fig. 6. Acquiring output data of a plurality of capacitance grid micrometers according to the step 6, and acquiring coordinates (x) of a plurality of measurement points after error compensationj,y j)，j＝1,2N, the number of measurement points set according to the invention, in which case N is 8. And setting the linear equation of the reference axis to be estimated as y-rx + s, and estimating r and s
Figure BDA0002510548570000091
An objective function of
Figure BDA0002510548570000092
The partial derivatives of r and s are separately calculated and made equal to zero,
Figure BDA0002510548570000093
and
Figure BDA0002510548570000094
the calculation method is as follows:
Figure BDA0002510548570000095
collecting coordinates (x) of a plurality of measurement points according to step 6j,yj) J is 1,2, 8, and the undetermined coefficient is set as βk(k ═ 1,2,. n), fitting a function
y(x)＝β0+β1x+β2x2…+βnxn
Setting the objective function in the same way
Figure BDA0002510548570000096
For beta isk(k ═ 1,2.. times, n) the partial derivative is calculated and made equal to zero, and the undetermined coefficient is calculated as:
Figure BDA0002510548570000097
so far, the implementation process steps of the invention are finished.
The foregoing detailed description of the preferred embodiments of the invention has been presented. It should be understood that numerous modifications and variations could be devised by those skilled in the art in light of the present teachings without departing from the inventive concepts. Therefore, the technical solutions available to those skilled in the art through logic analysis, reasoning and limited experiments based on the prior art according to the concept of the present invention should be within the scope of protection defined by the claims.

Claims (5)

1. An error compensation method for a hexagonal straightness detection system is characterized by comprising the following steps:
(1) selecting a calibration hexagonal shaft with the length of S, and loading the calibration hexagonal shaft to the hexagonal shaft straightness detection system;
(2) measuring at an actual measuring point C which is on the calibrated hexagonal shaft and has a distance of m with the left pneumatic three-jaw chuck to obtain the offset (C) in the direction of three groups of opposite surfaces of the calibrated hexagonal shaftα，Cβ，Cγ) And converting it into the axis vector coordinate (x) of point Cc,yc) (ii) a Defining the ideal measuring point of the calibrated hexagonal axis when the deflection error of the point C is 0 as C ', and setting the axis vector coordinate of the ideal measuring point C ' as (x 'c，y'c) The deflection error of point C relative to point C' is (Δ x)c，Δyc) Then there is (x)c，yc)＝(x'c+Δxc,y'c+Δyc)；
Measuring an actual measurement point D with the distance of m from the pneumatic three-jaw chuck on the right side on the calibrated hexagonal shaft to obtain an axis vector coordinate (x) of the point Dd,yd) (ii) a Defining the ideal measuring point of the calibrated hexagonal axis when the deflection error of the point D is 0 as D ', and setting the axis vector coordinate of the ideal measuring point D ' as (x 'd,y'd) The deflection error of point D relative to point D' is (Δ x)d,Δyd) Then there is (x)d,yd)＝(x'd+Δxd,y'd+Δyd)；
(3) Detaching the calibrated hexagonal shaft from the hexagonal shaft straightness detection system, rotating the calibrated hexagonal shaft by 180 degrees, and reloading the calibrated hexagonal shaft straightness detection system;
(4) measuring the point C rotated by 180 degrees to obtain the axis vector coordinate (x) of the actual measurement point C'c,y”c) Then there is (x) "c,y”c)＝(x'c-Δxc,y'c-Δyc)；
Measuring the D point rotated by 180 degrees to obtain the axis vector coordinate (x) of the actual measurement point D'd,y”d) Then there is (x) "d,y”d)＝(x'd-Δxd,y'd-Δyd)；
(5) Obtaining coordinates of ideal measuring points C ' and D ' from (2), (3) and (4), wherein the coordinates of the point C ' are:
Figure FDA0003539659760000011
and the coordinates of point D' are:
Figure FDA0003539659760000012
(6) according to the coordinates of the ideal measuring points C 'and D', determining a space straight line equation connecting C 'and D' as follows:
Figure FDA0003539659760000013
the ideal clamping point a ' of the left pneumatic three-jaw chuck on the calibrated hexagonal axis when the deflection error is 0 and the ideal clamping point B ' of the right pneumatic three-jaw chuck on the calibrated hexagonal axis are also on the spatial straight line, wherein the coordinates of the point a ' are as follows:
Figure FDA0003539659760000021
and the coordinates of point B' are:
Figure FDA0003539659760000022
(7) substituting the Z-axis coordinate of any point N to be measured between the point A 'and the point B' into the space linear equation to obtain the coordinate (X) of the point Nn,Yn) And converting it into a rotation error offset (N) in the direction of each opposite surface of the calibrated hexagonal axisα，Nβ，Nγ)；
(8) The calibrated hexagonal shaft is detached, the hexagonal shaft to be measured is loaded to the hexagonal shaft linearity detection system, and the offset (P ') of the detected point P in the direction of each opposite surface of the hexagonal shaft to be measured is determined for any point P to be measured on the hexagonal shaft to be measured'α，P'β，P'γ) Subtracting the amount of slewing error offset (P) calculated from (7)α，Pβ，Pγ) The result is the measurement result after error compensation;
(9) a plurality of points are taken on the hexagonal axis to be detected for detection, and the coordinates (x) of the plurality of points are obtained after error compensation and conversion are carried out according to the step (8)j,yj) N, · j ═ 1, 2; and calculating corresponding straightness errors by obtaining a reference axis and shaft curve fitting, thereby determining the maximum deflection position required by the straightening work of the shaft and the axial position corresponding to the measuring point.
2. The error compensation method for the hexagonal-axis straightness detection system according to claim 1, wherein a hexagonal axis with the best available straightness is selected as a calibration axis, six outer surfaces of the calibration axis are sequentially marked according to the sequence of the labels 1-6, a capacitive grating micrometer is arranged at a position m away from the two ends of the pneumatic three-jaw chuck, the left micrometer is marked as L, the right micrometer is marked as R, and the rest capacitive grating micrometers are equidistantly distributed in the middle of L, R; controlling the pneumatic three-jaw chucks at the two ends to clamp the calibration hexagonal shaft, marking the upward surface of the calibration hexagonal shaft as U before the computer starts to test, and marking the upward surface of the pneumatic three-jaw chucks at the two ends as U; the pneumatic three-jaw chuck clamps the calibration hexagonal shaft to rotate for a circle for measurement; when the pneumatic three-jaw chuck clamps the calibration hexagonal shaft to rotate for one circle for carrying out deflection measurement, the surface of the pneumatic three-jaw chuck structure marked as U and facing upwards is required to be kept consistent in the front and back rotating directions.
3. The error compensation method for the straightness detection system according to claim 2, wherein the calculation method for converting the offset in the direction of each opposite face of the calibrated hexagonal axis into the axis vector coordinate is as follows:
Figure FDA0003539659760000023
wherein i is the index of six outer surfaces of the hexagonal shaft, i is 1,2,3, deltaiI +3 is the offset of the hexagonal axis set with respect to the outer surfaces i and i +3, δa,δb,δcIs an offset, i.e. δ, as set forth in claim 1iAnd the i +3 corresponds to the offset on the three groups of opposite surfaces on the abc three-axis coordinate system, phi is an axis vector under the rectangular coordinate system, and the included angle between the theta axis vector and the x axis.
4. The error compensation method for a hexagonal straightness detection system of claim 3, wherein the reference axis is calculated by:
Figure FDA0003539659760000031
wherein N is the number of the measuring points, (x)j,yj) (j ═ 1,2,. N) are the coordinates of the N measurement points.
5. The error compensation method for a hexagonal-axis straightness detection system of claim 4, wherein the axis curve fitting calculation is:
y(x)＝β0+β1x+β2x2…+βnxn
Figure FDA0003539659760000032
Figure FDA0003539659760000033
wherein y (x) is an axial curve fitting function, βkAnd (k is 1,2.. n) is a undetermined coefficient of the axis curve expression.
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Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103182337A (en) * 2011-12-30 2013-07-03 湖南万容科技股份有限公司 Vertical crusher
CN103711536A (en) * 2012-09-29 2014-04-09 重庆长安汽车股份有限公司 Variable valve timing and direct-injection gasoline engine cam shaft

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4423469A1 (en) * 1994-07-05 1996-01-11 Elektrische Automatisierungs U Capacitive displacement measuring system used for non-contact position and vibration measurement at rotors in radial direction
CA3002927C (en) * 2003-03-28 2021-05-04 Inguran, Llc Apparatus, methods and processes for sorting particles and for providing sex-sorted animal sperm
JP5095159B2 (en) * 2006-08-31 2012-12-12 富士重工業株式会社 Electrolytic dressing grinding equipment
CN100509556C (en) * 2007-12-28 2009-07-08 北京航空航天大学 Connecting structure for middle and outside wings of unmanned aerial vehicle
CN101561272A (en) * 2009-05-19 2009-10-21 中国十七冶建设有限公司 Rotation method roller installation verticality alignment device and use method thereof
CN102581802A (en) * 2012-03-22 2012-07-18 河南省电力公司漯河供电公司 Screwdriver combined tool
CN208155259U (en) * 2018-04-20 2018-11-27 江苏华鹰光电科技有限公司 A kind of online ultrahigh speed high-precision micrometer
CN109373961B (en) * 2018-12-25 2020-03-24 浙江大学 Hexagonal axis straightness detection device and data processing method

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103182337A (en) * 2011-12-30 2013-07-03 湖南万容科技股份有限公司 Vertical crusher
CN103711536A (en) * 2012-09-29 2014-04-09 重庆长安汽车股份有限公司 Variable valve timing and direct-injection gasoline engine cam shaft

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