CN114234877B - Displacement sensor vector calibration method for R-test instrument - Google Patents

Displacement sensor vector calibration method for R-test instrument Download PDF

Info

Publication number
CN114234877B
CN114234877B CN202210183482.3A CN202210183482A CN114234877B CN 114234877 B CN114234877 B CN 114234877B CN 202210183482 A CN202210183482 A CN 202210183482A CN 114234877 B CN114234877 B CN 114234877B
Authority
CN
China
Prior art keywords
calibration
displacement sensor
vector
test instrument
displacement
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
CN202210183482.3A
Other languages
Chinese (zh)
Other versions
CN114234877A (en
Inventor
蒋云峰
朱绍维
牟文平
姜振喜
陶文坚
宋智勇
李�杰
李卫东
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Chengdu Aircraft Industrial Group Co Ltd
Original Assignee
Chengdu Aircraft Industrial Group Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Chengdu Aircraft Industrial Group Co Ltd filed Critical Chengdu Aircraft Industrial Group Co Ltd
Priority to CN202210183482.3A priority Critical patent/CN114234877B/en
Publication of CN114234877A publication Critical patent/CN114234877A/en
Application granted granted Critical
Publication of CN114234877B publication Critical patent/CN114234877B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • 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
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B11/00—Measuring arrangements characterised by the use of optical techniques
    • G01B11/02—Measuring arrangements characterised by the use of optical techniques for measuring length, width or thickness
    • 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
    • G01B21/042—Calibration or calibration artifacts

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Length Measuring Devices With Unspecified Measuring Means (AREA)
  • A Measuring Device Byusing Mechanical Method (AREA)

Abstract

The invention provides a displacement sensor vector calibration method for an R-test instrument, which comprises the following steps: step S1, preparing instrument calibration, relating to the setting of the displacement sensor origin, the processing coordinate system and the R-test instrument measurement coordinate system; s2, constructing an axial direction vector of the displacement sensor, and establishing a mathematical model between the displacement sensor and the coordinates of the sphere center of the calibration sphere; step S3, solving the axial direction vector of the displacement sensor based on the hyperstatic least square method according to the vector equation set expansion form of the mathematical model; and step S4, calibrating and verifying the instrument, constructing a calibration sphere center coordinate inverse solution model, and completing the verification of the sphere center coordinate by combining the sphere center coordinate conversion models in different installation modes. The invention does not need complicated intelligent algorithm solution, solves the problem of the attitude calibration of the displacement sensor for the R-test instrument, has simple process and quick calculation, improves the detection efficiency and is convenient for implementing automatic measurement.

Description

Displacement sensor vector calibration method for R-test instrument
Technical Field
The invention belongs to the technical field of calibration of detection instruments, and particularly relates to a displacement sensor vector calibration method for an R-test instrument.
Background
The five-axis numerical control machine tool has the capability of processing a complex curved surface, is widely applied to the field of manufacturing high-end equipment such as aviation structural parts, turbine blades, medical instruments and the like, and has increasingly serious problem of reduction of the processing precision of the five-axis machine tool caused by unstable precision control of a machine tool rotating shaft. In contrast, ISO230-1 proposes an R-test instrument, which is provided with 3 displacement sensors distributed in a three-dimensional space according to different design schemes. Although the distribution mode is slightly different, the method can be used for measuring the space precision of the rotating shaft, compared with instruments such as a ball rod instrument and a laser tracker, the R-test instrument can simultaneously obtain errors in three directions by one-time measurement, and has the advantages of high precision, high efficiency, simple structure and the like.
At present, according to the structure of the R-test instrument, the R-test instrument is divided into a contact type and a non-contact type. Liu Da we et al (Liu Da Wei et al, an R-test ball head and ball center detection device structure optimization design method [ J ]. Mechanics engineering report, 2016) have constructed the mathematical relationship between the detection calibration ball and the ball head displacement sensor, the construction method is based on the design of the contact R-test instrument, but the specific calculation method of the conversion between the displacement sensor and the ball center coordinate is not detailed. Penkang et al (Penkang et al, a non-contact R-test instrument field calibration method research [ J ] manufacturing technology and machine tool, 2019 (10)) researched a non-contact R-test instrument calibration method using an eddy current displacement sensor, and a differential evolution algorithm is used for solving a calibration equation set. Subsequently, Penkang et al (Penkang et al. calibration of a contact R-test measuring instrument and a calculation method of a sphere center coordinate research [ J ]. mechanical science and technology, 2020, 39(9):1385 1389) obtain a calibration equation set of the position of the ball head sensor by constructing a vector equation set aiming at the calibration of the contact R-test instrument, and still solve the calibration equation set by using a differential evolution algorithm. However, no matter a contact type or non-contact type R-test instrument, the calculation of the differential evolution algorithm is related to the selection of an initial value, the performance of a computer and the like, and is not beneficial to the rapid calculation of the subsequent spherical center coordinates, and for the structural form of the R-test instrument, the posture of the displacement sensor after being installed is directly reflected by the processing precision of the instrument base, so that the calibration precision of the instrument is influenced, but the calibration method related to the patent does not embody the characteristics. In general, the existing calibration method for the R-test instrument has the problem of low calculation efficiency in the forward calculation and the backward calculation of the spherical center coordinates during calibration.
Disclosure of Invention
The invention provides a displacement sensor vector calibration method for an R-test instrument, aiming at the problem of low calculation efficiency in both the forward calculation and the backward calculation of a spherical center coordinate in the calibration process of the calibration method of the R-test instrument in the prior art.
In order to achieve the above purpose, the invention comprises the following concrete contents:
the invention provides a displacement sensor vector calibration method for an R-test instrument, which comprises the following steps:
step S1: calibration preparation, namely installing an R-test instrument on a machine tool workbench, determining a machining coordinate system and an R-test instrument measuring coordinate system, and simultaneously recording the displacement value of a displacement sensor;
step S2: constructing a displacement sensor attitude calibration model, setting an axial direction vector of the displacement sensor, and establishing a mathematical model between the displacement sensor and a calibration sphere center coordinate;
step S3: solving a vector equation set of the displacement sensor, and solving the vector in the axial direction of the displacement sensor based on a hyperstatic least square method according to an expansion form of the vector equation set;
step S4: and (4) calibration verification, namely constructing a calibration sphere center coordinate inverse solution model according to the displacement sensor posture calibration model constructed in the step S2, and completing the conversion and verification of the calibration sphere center coordinate by combining different installation modes of the R-test instrument.
In order to better implement the present invention, further, the specific steps of the calibration preparation performed in step S1 are as follows:
step S1.1: clamping the calibration ball on a machine tool spindle;
step S1.2: installing an R-test instrument on a machine tool workbench;
step S1.3: after the calibration ball and the R-test instrument are installed, moving the calibration ball at the main shaft end to be right above the R-test instrument;
step S1.4: slowly moving the calibration ball in the Z direction to enable the center of the calibration ball to be located at the intersection point of the axes of the three displacement sensors in the R-test instrument, enabling the displacement values of the three displacement sensors to be consistent, and recording the displacement values of the three displacement sensors at the moment as di(i=1,2,3)；
Step S1.5: determining X, Y, Z coordinates of the current machine tool coordinate system at the end of the numerical control machine tool as machining coordinate system coordinates, and simultaneously reading d in software of an R-test instrumentiSet as the origin reading d0And the intersection point of the axes of the three displacement sensors is determined as the origin of the measuring coordinate system of the R-test instrument, so that the directions of the measuring coordinate system of the R-test instrument, the processing coordinate system and the machine tool coordinate system are consistent in the calibration state.
In order to better implement the present invention, further, the specific steps of constructing the displacement sensor posture calibration model in step S2 are as follows:
step S2.1: and expressing the axial direction vector of the displacement sensor in an R-test instrument measurement coordinate system as follows:
Figure 100002_DEST_PATH_IMAGE001
step S2.2: according to the calibration ball center in the step S1.1 located at the intersection of the axes of the three displacement sensors in the R-test instrument, the center of the calibration ball center at the center of the 3 displacement sensors can be obtained, and in the measurement coordinate system of the R-test instrument, the initial coordinates of the ball center of the spherical surface at the top of the displacement sensor at this time are:
Figure 537136DEST_PATH_IMAGE002
wherein R is the radius of a calibration sphere, and R is the radius of the spherical surface of the displacement sensor probe;
step S2.3: sequentially moving the calibration ball at the main shaft end to different calibration point positions under the machining coordinate system
Figure 100002_DEST_PATH_IMAGE003
,
Figure 391960DEST_PATH_IMAGE004
N is the total number of moves, and after each move is completed, the displacement readings of the 3 displacement sensors are
Figure 100002_DEST_PATH_IMAGE005
And obtaining the change of the spherical center coordinates of the probe of the displacement sensor along with the calibration process as follows:
Figure 499593DEST_PATH_IMAGE006
wherein the content of the first and second substances,
Figure 100002_DEST_PATH_IMAGE007
，dijindicating the displacement of the ith displacement sensor in the jth movement;
step S2.4: in the calibration process, the displacement sensor and the calibration ball are always kept in a contact state, and the following vector equation set is obtained:
Figure 81753DEST_PATH_IMAGE008
any one of the three displacement sensors can be calibrated by the position of the calibration point and the combination of the vector equation set.
In order to better implement the present invention, further, the specific steps of solving the displacement sensor vector equation set in step S3 are as follows:
step S3.1: expanding the vector equation set:
Figure 427284DEST_PATH_IMAGE010
wherein the content of the first and second substances,
Figure 100002_DEST_PATH_IMAGE011
and
Figure 453009DEST_PATH_IMAGE012
the meaning is the same as that in step S2.3;
step S3.2: the system of vector equations in step S3.1 is further expanded as:
Figure 100002_DEST_PATH_IMAGE013
since the unit vector of the axial direction vector of each displacement sensor satisfies the principle that the sum of squares is 1, the complementary equation according to the principle that the unit vector satisfies the sum of squares is 1 is expressed as:
Figure 906992DEST_PATH_IMAGE014
let L = R + R, and in combination with the expansion equation and the complementary equation of step S3.2, the vector equation set is rewritten into a matrix form as:
Figure 100002_DEST_PATH_IMAGE015
wherein:
Figure 433789DEST_PATH_IMAGE016
Figure 100002_DEST_PATH_IMAGE017
Figure 40351DEST_PATH_IMAGE018
from the least squares solution of the hyperstatic equation:
Figure 100002_DEST_PATH_IMAGE019
the vector V is an axial direction vector of the displacement sensor, namely an attitude vector of the displacement sensor, the vector V comprises all elements of the axial direction vector of the displacement sensor, and the calibration of the three displacement sensors can be completed by repeating the step on each displacement sensor;
step S3.3: in step S2.3 and step S2.4, different positions of the calibration point need to be designed
Figure 492104DEST_PATH_IMAGE020
The calibration purpose is achieved, and the setting mode of the calibration points is as follows: the movable range of the X, Y, Z axis is established as a space grid, and boundary points, the middle points of face diagonal lines and the middle points of body diagonal lines on the grid are taken as calibration points, so that the design requirements on the number of the calibration points and the precision of the calibration points can be met.
In order to better implement the present invention, further, the specific steps of the calibration verification of the R-test instrument in step S4 are as follows:
step S4.1: according to the inverse solution model of the coordinates of the center of sphere of the calibration sphere constructed in the step S2, the vector equation set is re-derived as follows, and the vector equation set is transformed into the following form:
Figure 777592DEST_PATH_IMAGE022
because three displacement sensors are needed to determine the coordinates of the center of the calibration sphere, the vector equation set in step S4.1 is rewritten into a matrix form:
Figure DEST_PATH_IMAGE023
wherein:
Figure DEST_PATH_IMAGE025
Figure 373658DEST_PATH_IMAGE026
Figure DEST_PATH_IMAGE027
L=R+r；
and (3) calculating the matrix to obtain the coordinates of the sphere center of the calibration sphere:
Figure 834726DEST_PATH_IMAGE028
(Vector)
Figure DEST_PATH_IMAGE029
namely the coordinates (x, y, z) of the sphere center of the calibration sphere;
step S4.2: and (4) on the basis of the step (S4.1), carrying out the calibration verification process of the R-test instrument, and verifying the accuracy of the calibration result.
In order to better implement the invention, further, after the calibration verification of the R-test instrument is completed, the installation form of the instrument is various.
In order to better realize the invention, further, when the verification is carried out under the condition that the installation position of the instrument is not changed, the instrument state is consistent with the calibration state, so that the spindle end calibration ball is directly driven to move to the set verification point position
Figure 717101DEST_PATH_IMAGE030
The software matched with the instrument can automatically read the value d of the displacement sensor after reaching the verification pointkKnowing the current displacement sensor reading dkOriginal reading d0And the axial vector Vi (i =1,2,3) of the displacement sensor is substituted into the step S4.1, and the verification point vector can be completed
Figure 99671DEST_PATH_IMAGE029
Calculating (1);
if it is
Figure DEST_PATH_IMAGE031
If not, continuing to perform the step S2 and the step S3, increasing the number of the calibration points and improving the calibration precision.
In order to better implement the invention, further, when the mounting position of the instrument is remounted, the posture of the remounted displacement sensor is changed with the calibration, and the calibration verification of the instrument specifically comprises the following steps:
step 1: firstly, the main shaft end calibration ball is driven to move to the original point position during calibration, and the reading of the displacement sensor and the reading d can be used0The difference value is judged, meanwhile, a machining coordinate system is set at the position of the point, the machining coordinate system is still consistent with a machine tool coordinate system, but the R-test instrument measurement coordinate system is inconsistent with the machining coordinate system;
step 2: starting from the origin, respectively driving the main shaft calibration ball to move in the X, Y direction of the machining coordinate system1、l2mm; respectively obtain readings of the displacement sensors
Figure 827325DEST_PATH_IMAGE032
、
Figure DEST_PATH_IMAGE033
；
And step 3: establishing a conversion relation between a measurement coordinate system and a processing coordinate system of the original R-test instrument by using the following formula:
Figure 408479DEST_PATH_IMAGE034
wherein the content of the first and second substances,
Figure DEST_PATH_IMAGE035
Figure 930596DEST_PATH_IMAGE036
Figure DEST_PATH_IMAGE037
represents a cross product between two vectors;
and 4, step 4: then the main shaft end calibration ball is driven to move to the set verification point position
Figure 597201DEST_PATH_IMAGE038
Substituting the step S4.1 to complete the verification point vector
Figure DEST_PATH_IMAGE039
The calculation of (2):
Figure 128545DEST_PATH_IMAGE040
if it is
Figure 100002_DEST_PATH_IMAGE041
Otherwise, the calibration is accurate, and the steps S2, S3 are continued, andthe number of calibration points is increased, and the calibration precision is improved.
In order to better implement the present invention, further, in the matrix equation established in the step S3.2, when the displacement sensor is a laser displacement sensor, L = R.
In order to better implement the invention, the calibration ball for the R-test instrument is used with the R-test instrument and has a diameter of 22 mm.
The invention has the following beneficial effects:
1. the invention provides a displacement sensor vector calibration method for an R-test instrument, which solves the difficult problem of the posture calibration of a displacement sensor for the R-test instrument, including but not limited to a ball head displacement sensor and a laser displacement sensor, and has the fundamental reason that the displacement of the ball head displacement sensor or the laser displacement sensor shows nonlinear displacement change along with the detection position, and the traditional scheme adopts an intelligent algorithm to solve.
2. The displacement sensor vector calibration method for the R-test instrument provided by the invention realizes accurate measurement of the micro-displacement change of the calibration ball, and after one-time calibration is finished, the verification method adopting the step S4 still has higher precision in subsequent actual measurement, thereby avoiding repeated calibration, improving the detection efficiency and being particularly convenient for automatic measurement.
Drawings
FIG. 1 is a flow chart of the present invention for calibrating a displacement sensor in an R-test instrument;
FIG. 2 is a model diagram of the displacement sensor of the present invention as a ball head displacement sensor;
FIG. 3 is a model diagram of the displacement sensor of the present invention as a laser displacement sensor;
FIG. 4 is a schematic diagram of a positional relationship between a ball head displacement sensor and a calibration ball;
FIG. 5 is a schematic diagram showing the positional relationship between the laser displacement sensor and the calibration ball;
the device comprises a base, a calibration ball, a displacement sensor and a control unit, wherein the base comprises a base, a calibration ball and a displacement sensor, and the calibration ball is arranged on the base, and the displacement sensor is arranged on the base, wherein the calibration ball is arranged on the base, and the displacement sensor is arranged on the displacement sensor.
Detailed Description
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it should be understood that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments, and therefore should not be considered as a limitation to the scope of protection. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention.
In the description of the present invention, it is to be noted that, unless otherwise explicitly specified or limited, the terms "disposed," "connected," and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.
Example 1:
the invention provides a vector calibration method of a displacement sensor 2 for an R-test instrument, which comprises the following steps as shown in figure 1:
step S1: calibration preparation, namely installing an R-test instrument on a machine tool workbench, determining a machining coordinate system and an R-test instrument measuring coordinate system, and simultaneously recording the displacement value of the displacement sensor 2;
step S2: constructing a posture calibration model of the displacement sensor 2, setting an axial direction vector of the displacement sensor 2, and establishing a mathematical model between the spherical center coordinates of the displacement sensor 2 and the calibration ball 1;
step S3: solving a vector equation set of the displacement sensor 2, and solving the vector of the displacement sensor 2 in the axial direction based on a hyperstatic least square method according to an expansion form of the vector equation set;
step S4: and (4) calibration verification, namely constructing a reverse solution model of the spherical center coordinates of the calibration ball 1 according to the posture calibration model of the displacement sensor 2 constructed in the step S2, and completing the conversion and verification of the spherical center coordinates of the calibration ball 1 by combining different installation modes of the R-test instrument.
The working principle is as follows: the displacement sensor 2 vector calibration method for the R-test instrument provided by the invention starts from a model mechanism, does not need complicated intelligent algorithm solution, solves the problem of posture calibration of the displacement sensor 2 for the R-test instrument, including but not limited to a ball head displacement sensor and a laser displacement sensor, has the advantages of simple process and quick calculation, improves the detection efficiency and is convenient for implementing automatic measurement.
Example 2:
in this embodiment, on the basis of embodiment 1, as shown in fig. 2 and 4, calibration of the calibration ball 1 is completed by using the ball head displacement sensor 2.
The working principle is as follows: the structural model of the R-test instrument is shown in FIG. 2, and mainly comprises 3 ball head displacement sensors 2 and a calibration ball 1 which are uniformly distributed. And calibrating the posture of the ball head displacement sensor 2 according to the space geometric relation between the center of the calibration ball 1 and the ball head displacement sensor 2.
The specific implementation steps are as follows:
step S1: calibration preparation, namely installing an R-test instrument on a machine tool workbench, determining a machining coordinate system and an R-test instrument measuring coordinate system, and simultaneously recording the displacement value of the ball head displacement sensor 2;
step S2: constructing a posture calibration model of the ball head displacement sensor 2, setting an axial direction vector of the ball head displacement sensor 2, and establishing a mathematical model between the ball head displacement sensor 2 and a spherical center coordinate of the calibration ball 1;
step S3: solving a vector equation set of the ball head displacement sensor 2, and solving the axial direction vector of the ball head displacement sensor 2 based on a hyperstatic least square method according to an expansion form of the vector equation set;
step S4: and (4) calibration verification, namely constructing a calibration ball 1 spherical center coordinate inverse solution model according to the ball head displacement sensor 2 posture calibration model constructed in the step S2, and completing the conversion and verification of the spherical center coordinate of the calibration ball 1 by combining different installation modes of an R-test instrument.
The step S1 specifically includes the following steps:
step S1.1: clamping the calibration ball 1 on a machine tool spindle;
step S1.2: installing an R-test instrument on a machine tool workbench;
step S1.3: after the calibration balls 1 and the R-test instrument are installed, the calibration balls 1 at the main shaft end are moved to be right above the R-test instrument, as shown in figure 2, V1、V2、V3The vector of the axial direction of the 3 ball head displacement sensors 2 is the attitude vector of the sensors. The calibration aims to accurately calculate the attitude vector of the sensor and realize the conversion of the reading of the sensor to the coordinates of the sphere center;
step S1.4: slowly moving the calibration ball 1 in the Z direction to enable the center of the calibration ball 1 to be located at the intersection point of the axes of the three ball head displacement sensors 2 in the R-test instrument, enabling the displacement values of the three ball head displacement sensors 2 to be consistent, and recording the displacement values of the three ball head displacement sensors 2 as di(i=1,2,3)；
Step S1.5: determining X, Y, Z coordinates of the current machine tool coordinate system at the end of the numerical control machine tool as machining coordinate system coordinates, and simultaneously reading d in software of an R-test instrumentiSet as the origin reading d0And the intersection point of the axes of the three ball head displacement sensors 2 is determined as the origin of the measurement coordinate system of the R-test instrument, so that the directions of the measurement coordinate system of the R-test instrument, the processing coordinate system and the machine tool coordinate system are consistent in the calibration state.
In order to better implement the present invention, further, the specific steps of constructing the ball head displacement sensor 2 attitude calibration model in step S2 include:
step S2.1: the axial direction vector of the ball head displacement sensor 2 is expressed as follows in an R-test instrument measurement coordinate system:
Figure 564206DEST_PATH_IMAGE042
step S2.2: according to the position of the center of the calibration ball 1 located at the intersection point of the axes of the three ball head displacement sensors 2 in the R-test instrument described in step S1.1, the center of the calibration ball 1 located at the center positions of the 3 ball head displacement sensors 2 can be obtained, and under the measurement coordinate system of the R-test instrument, the initial coordinate of the center of the ball surface at the top end of the ball head displacement sensor 2 at this time is:
Figure 100002_DEST_PATH_IMAGE043
wherein R is the radius of a calibration ball 1, and R is the radius of the spherical surface of a probe of a ball head displacement sensor 2;
step S2.3: sequentially moving the main shaft end calibration ball 1 to different calibration point positions under the machining coordinate system
Figure 522803DEST_PATH_IMAGE044
,
Figure 100002_DEST_PATH_IMAGE045
N is the total number of movements, and after each movement is completed, the displacement readings of the 3 ball head displacement sensors 2 are
Figure 676704DEST_PATH_IMAGE046
The change of the spherical center coordinates of the probe spherical surface of the ball head displacement sensor 2 along with the calibration process is obtained as follows:
Figure DEST_PATH_IMAGE047
wherein the content of the first and second substances,
Figure 746160DEST_PATH_IMAGE048
，dijthe displacement of the ith ball head displacement sensor 2 in the jth movement is shown;
step S2.4: in the calibration process, the ball head displacement sensor 2 and the calibration ball 1 are always kept in a contact state, and the following vector equation set is obtained:
Figure 505169DEST_PATH_IMAGE008
through the position of the calibration point and the combination of the vector equation set, any one ball head displacement sensor 2 in the three ball head displacement sensors 2 can be calibrated.
In order to better implement the present invention, further, the specific steps of solving the vector equation set of the ball head displacement sensor 2 in step S3 are as follows:
step S3.1: expanding the vector equation set:
Figure 978875DEST_PATH_IMAGE050
wherein the content of the first and second substances,
Figure DEST_PATH_IMAGE051
and
Figure 4426DEST_PATH_IMAGE052
the meaning is the same as that in step S2.3;
step S3.2: the system of vector equations in step S3.1 is further expanded to:
Figure 956201DEST_PATH_IMAGE054
since the unit vector of the axial direction vector of each ball head displacement sensor 2 satisfies the principle that the sum of squares is 1, the complementary equation according to the principle that the unit vector satisfies the sum of squares is 1 is expressed as:
Figure DEST_PATH_IMAGE055
let L = R + R, and in combination with the expansion equation and the complementary equation of step S3.2, the vector equation set is rewritten into a matrix form as:
Figure 756667DEST_PATH_IMAGE056
wherein:
Figure 401275DEST_PATH_IMAGE016
Figure 982298DEST_PATH_IMAGE017
Figure 737764DEST_PATH_IMAGE018
from the least squares solution of the hyperstatic equation:
Figure DEST_PATH_IMAGE057
the vector V is an axial vector of the ball head displacement sensor 2, namely an attitude vector of the ball head displacement sensor 2, and comprises all elements of the axial vector of the ball head displacement sensor 2, and the calibration of the three ball head displacement sensors 2 can be completed by repeating the step on each ball head displacement sensor 2;
step S3.3: in step S2.3 and step S2.4, different positions of the calibration point need to be designed
Figure 392737DEST_PATH_IMAGE058
The calibration purpose is achieved, and the setting mode of the calibration points is as follows: the movable range of the X, Y, Z axis is established as a space grid, and boundary points, the middle points of face diagonal lines and the middle points of body diagonal lines on the grid are taken as calibration points, so that the design requirements on the number of the calibration points and the precision of the calibration points can be met.
In order to better implement the present invention, further, the specific steps of the calibration verification of the R-test instrument in step S4 are as follows:
step S4.1: according to the step S2, constructing the inverse solution model of the coordinates of the center of sphere 1, and re-deriving the vector equation set as follows, so as to transform the vector equation set into the form:
Figure 208246DEST_PATH_IMAGE060
because three ball head displacement sensors 2 are needed to determine the coordinates of the center of the calibration ball 1, the vector equation set in the step S4.1 is rewritten into a matrix form:
Figure DEST_PATH_IMAGE061
wherein:
Figure DEST_PATH_IMAGE063
Figure 745406DEST_PATH_IMAGE064
Figure DEST_PATH_IMAGE065
L=R+r；
and (3) performing operation on the matrix to obtain the spherical center coordinates of the calibration sphere 1:
Figure 22673DEST_PATH_IMAGE066
(Vector)
Figure DEST_PATH_IMAGE067
namely the coordinates (x, y, z) of the center of the calibration ball 1;
step S4.2: and (4) on the basis of the step (S4.1), carrying out the calibration verification process of the R-test instrument, and verifying the accuracy of the calibration result.
In order to better implement the invention, further, after the calibration verification of the R-test instrument is completed, the installation form of the instrument is various.
In order to better realize the invention, further, when the verification is carried out under the condition that the installation position of the instrument is not changed, the instrument state is consistent with the calibration state, so that the spindle end calibration ball 1 is directly driven to move to the set verification point position
Figure 407518DEST_PATH_IMAGE068
Software matched with the instrument can automatically read the numerical value d of the ball head displacement sensor 2 after reaching the verification pointkKnowing the current reading d of the ball head displacement sensor 2k Original reading d 02 axis vector V of ball head displacement sensori(i =1,2,3), and substituting into step S4.1 can complete the verification point vector
Figure 252983DEST_PATH_IMAGE067
Calculating (1);
if it is
Figure DEST_PATH_IMAGE069
Otherwise, the step S2 and the step S3 are continued, and the number of calibration points is increased, thereby improving the calibration precision.
In order to better implement the invention, further, when the mounting position of the instrument is remounted, the posture and calibration of the remounted ball head displacement sensor 2 are changed, and the calibration verification of the instrument specifically comprises the following steps:
step 1: firstly, the main shaft end calibration ball 1 is driven to move to the original point position during calibration, and the reading of the ball head displacement sensor 2 and the reading d can be used0The difference between the two coordinate systems is judged, and meanwhile, a machining coordinate system is set at the position of the point, the machining coordinate system is still consistent with a machine tool coordinate system, but the R-test instrument measurement coordinate system is inconsistent with the machining coordinate system;
step 2: starting from the origin, the spindle calibration balls 1 are respectively driven to move in the X, Y direction of the machining coordinate system1、l2mm; respectively obtain the readings of the ball head displacement sensor 2
Figure 90489DEST_PATH_IMAGE070
、
Figure DEST_PATH_IMAGE071
；
And step 3: establishing a conversion relation between a measurement coordinate system and a processing coordinate system of the original R-test instrument by using the following formula:
Figure 849410DEST_PATH_IMAGE072
wherein, the first and the second end of the pipe are connected with each other,
Figure DEST_PATH_IMAGE073
，
Figure 88761DEST_PATH_IMAGE074
，
Figure DEST_PATH_IMAGE075
represents a cross product between two vectors;
and 4, step 4: then the main shaft end calibration ball 1 is driven to move to the set verification point position
Figure 901865DEST_PATH_IMAGE076
Step S4.1 is substituted to complete the verification point vector
Figure DEST_PATH_IMAGE077
The calculation of (2):
Figure 226667DEST_PATH_IMAGE078
if it is
Figure DEST_PATH_IMAGE079
Otherwise, the step S2 and the step S3 are continued, and the number of calibration points is increased, thereby improving the calibration precision.
In order to better implement the invention, the calibration ball 1 for the R-test instrument is used with the R-test instrument and has a diameter of 22 mm.
Other parts of this embodiment are the same as any of embodiment 1, and thus are not described again.
Example 3:
in this embodiment, on the basis of any one of the above embodiments 1-2, as shown in fig. 3 and 5, the calibration of the calibration ball 1 is completed by using the laser displacement sensor 2.
The working principle is as follows: the structural model of the R-test instrument is shown in FIG. 2, and mainly comprises 3 laser displacement sensors 2 and a calibration sphere 1 which are uniformly distributed. And calibrating the posture of the laser displacement sensor 2 according to the space geometric relation between the sphere center of the calibration sphere 1 and the laser displacement sensor 2.
The specific implementation steps are as follows:
step S1: calibration preparation, namely installing an R-test instrument on a machine tool workbench, determining a processing coordinate system and an R-test instrument measuring coordinate system, and simultaneously recording the displacement value of the laser displacement sensor 2;
step S2: constructing a posture calibration model of the laser displacement sensor 2, setting an axial direction vector of the laser displacement sensor 2, and establishing a mathematical model between the spherical center coordinates of the laser displacement sensor 2 and the calibration ball 1;
step S3: solving a vector equation set of the laser displacement sensor 2, and solving the vector of the displacement sensor 2 in the axial direction based on a hyperstatic least square method according to an expansion form of the vector equation set;
step S4: and (5) calibration verification, namely constructing a calibration ball 1 spherical center coordinate inverse solution model according to the laser displacement sensor 2 posture calibration model constructed in the step S2, and completing the conversion and verification of the calibration ball 1 spherical center coordinate by combining different installation modes of the R-test instrument.
The step S1 specifically includes the following steps:
step S1.1: clamping the calibration ball 1 on a machine tool spindle;
step S1.2: installing an R-test instrument on a machine tool workbench;
step S1.3: after the calibration ball 1 and the R-test instrument are installed, the calibration ball 1 at the main shaft end is movedMove right above the R-test instrument, as shown in FIG. 2, V1、V2、V3The vector of the axial direction of the 3 laser displacement sensors 2, namely the attitude vector of the sensors. The calibration aims to accurately calculate the attitude vector of the sensor and realize the conversion of the reading of the sensor to the coordinates of the sphere center;
step S1.4: slowly moving the calibration ball 1 in the Z direction to enable the center of the calibration ball 1 to be located at the intersection point of the axes of the three laser displacement sensors 2 in the R-test instrument, enabling the displacement values of the three laser displacement sensors 2 to be consistent, and recording the displacement values of the three laser displacement sensors 2 as di(i=1,2,3)；
Step S1.5: determining X, Y, Z coordinates of the current machine tool coordinate system at the end of the numerical control machine tool as machining coordinate system coordinates, and simultaneously reading d in software of an R-test instrumentiSet as the origin reading d0And the intersection point of the axes of the three laser displacement sensors 2 is determined as the origin of the measuring coordinate system of the R-test instrument, so that the directions of the measuring coordinate system of the R-test instrument, the processing coordinate system and the machine tool coordinate system are consistent in the calibration state.
In order to better implement the present invention, the specific steps of constructing the attitude calibration model of the laser displacement sensor 2 in step S2 include:
step S2.1: the axial direction vector of the laser displacement sensor 2 is expressed in an R-test instrument measurement coordinate system as follows:
Figure 48999DEST_PATH_IMAGE080
step S2.2: according to the position of the center of the calibration ball 1 at the intersection point of the three laser axes in the R-test instrument described in step S1.1, the center of the calibration ball 1 at the center positions of the 3 laser displacement sensors 2 can be obtained, and in the measurement coordinate system of the R-test instrument, the initial coordinates of the center of the spherical surface at the top end of the laser displacement sensor 2 at this time are:
Figure DEST_PATH_IMAGE081
wherein R is the radius of a calibration ball 1, and R is the radius of the spherical surface of a probe of a laser displacement sensor 2;
step S2.3: sequentially moving the main shaft end calibration ball 1 to different calibration point positions under the machining coordinate system
Figure 267490DEST_PATH_IMAGE082
,
Figure DEST_PATH_IMAGE083
N is the total number of movements, and after each movement is completed, the displacement readings of the 3 laser displacement sensors 2 are as
Figure 2228DEST_PATH_IMAGE084
The change of the spherical center coordinates of the probe of the laser displacement sensor 2 along with the calibration process is obtained as follows:
Figure DEST_PATH_IMAGE085
wherein the content of the first and second substances,
Figure 63594DEST_PATH_IMAGE086
，dijindicating the displacement of the ith laser displacement sensor 2 in the jth movement;
step S2.4: in the calibration process, the laser displacement sensor 2 and the calibration ball 1 are always kept in a contact state, and the following vector equation set is obtained:
Figure DEST_PATH_IMAGE087
any one displacement sensor 2 in the three laser displacement sensors 2 can be calibrated by the position of the calibration point and the combination of the vector equation set.
In order to better implement the present invention, further, the specific steps of solving the vector equation set of the laser displacement sensor 2 in step S3 are as follows:
step S3.1: expanding the vector equation set:
Figure DEST_PATH_IMAGE089
wherein the content of the first and second substances,
Figure 158458DEST_PATH_IMAGE090
and
Figure DEST_PATH_IMAGE091
the meaning is the same as that in step S2.3;
step S3.2: the system of vector equations in step S3.1 is further expanded to:
Figure DEST_PATH_IMAGE093
since the unit vector of the axial direction vector of each laser displacement sensor 2 satisfies the principle that the sum of squares is 1, the complementary equation according to the principle that the unit vector satisfies the sum of squares is 1 is expressed as:
Figure 152827DEST_PATH_IMAGE094
assuming L = R, the vector equation set is rewritten into a matrix form by combining the expansion equation and the complementary equation of step S3.2:
Figure DEST_PATH_IMAGE095
wherein:
Figure 466258DEST_PATH_IMAGE016
Figure 93548DEST_PATH_IMAGE017
Figure 211677DEST_PATH_IMAGE018
from the least squares solution of the hyperstatic equation:
Figure 608023DEST_PATH_IMAGE096
the vector V is an axial vector of the laser displacement sensor 2, namely an attitude vector of the laser displacement sensor 2, and comprises all elements of the axial vector of the laser displacement sensor 2, and the calibration of the three laser displacement sensors 2 can be completed by repeating the step on each laser displacement sensor 2;
step S3.3: in the step S2.3 and the step S2.4, different calibration point positions need to be designed
Figure DEST_PATH_IMAGE097
The calibration purpose is achieved, and the setting mode of the calibration points is as follows: the movable range of the X, Y, Z axis is established as a space grid, and boundary points, the middle points of face diagonal lines and the middle points of body diagonal lines on the grid are taken as calibration points, so that the design requirements on the number of the calibration points and the precision of the calibration points can be met.
In order to better implement the present invention, further, the specific steps of the calibration verification of the R-test instrument in step S4 are as follows:
step S4.1: according to the step S2, constructing the inverse solution model of the coordinates of the center of sphere 1, and re-deriving the vector equation set as follows, so as to transform the vector equation set into the form:
Figure DEST_PATH_IMAGE099
because three laser displacement sensors 2 are arranged to determine the coordinates of the center of the calibration sphere 1, the vector equation set in the step S4.1 is rewritten into a matrix form:
Figure 605935DEST_PATH_IMAGE100
wherein:
Figure 720522DEST_PATH_IMAGE102
Figure DEST_PATH_IMAGE103
Figure 298133DEST_PATH_IMAGE104
L=R；
and (3) performing operation on the matrix to obtain the spherical center coordinates of the calibration sphere 1:
Figure DEST_PATH_IMAGE105
(Vector)
Figure 735937DEST_PATH_IMAGE106
namely the coordinates (x, y, z) of the center of the calibration ball 1;
step S4.2: and (4) on the basis of the step (S4.1), carrying out the calibration verification process of the R-test instrument, and verifying the accuracy of the calibration result.
In order to better implement the invention, further, after the calibration verification of the R-test instrument is completed, the installation form of the instrument is various.
In order to better realize the invention, further, when the verification is carried out under the condition that the installation position of the instrument is not changed, the instrument state is consistent with the calibration state, so that the spindle end calibration ball 1 is directly driven to move to the set verification point position
Figure DEST_PATH_IMAGE107
The software matched with the instrument can automatically read the laser displacement transmission after reaching the verification pointSensor 2 value dkKnowing the current laser displacement sensor 2 reading dkThe origin reading d 02 axis vector V of laser displacement sensori(i =1,2,3), substituting into step S4.1 may complete the verification point vector
Figure 248958DEST_PATH_IMAGE108
Calculating (1);
if it is
Figure DEST_PATH_IMAGE109
Otherwise, the step S2 and the step S3 are continued, and the number of calibration points is increased, thereby improving the calibration precision.
In order to better implement the invention, further, when the mounting position of the instrument is remounted, the posture and calibration of the remounted laser displacement sensor 2 are changed, and the calibration verification of the instrument specifically comprises the following steps:
step 1: firstly, the main shaft end calibration ball 1 is driven to move to the original point position during calibration, and the reading of the laser displacement sensor 2 and the reading d can be used0The difference value is judged, meanwhile, a machining coordinate system is set at the position of the point, the machining coordinate system is still consistent with a machine tool coordinate system, but the R-test instrument measurement coordinate system is inconsistent with the machining coordinate system;
step 2: starting from the origin, the spindle calibration balls 1 are respectively driven to move in the X, Y direction of the machining coordinate system1、l2mm; respectively obtain the readings of the laser displacement sensor 2
Figure 37791DEST_PATH_IMAGE110
、
Figure DEST_PATH_IMAGE111
；
And step 3: establishing a conversion relation between a measurement coordinate system and a processing coordinate system of the original R-test instrument by using the following formula:
Figure 278148DEST_PATH_IMAGE112
wherein the content of the first and second substances,
Figure DEST_PATH_IMAGE113
，
Figure 55612DEST_PATH_IMAGE114
，
Figure DEST_PATH_IMAGE115
represents a cross product between two vectors;
and 4, step 4: then the main shaft end calibration ball 1 is driven to move to the set verification point position
Figure 988801DEST_PATH_IMAGE116
Substituting the step S4.1 to complete the verification point vector
Figure DEST_PATH_IMAGE117
The calculation of (2):
Figure 484505DEST_PATH_IMAGE118
if it is
Figure DEST_PATH_IMAGE119
Otherwise, the step S2 and the step S3 are continued, and the number of calibration points is increased, thereby improving the calibration precision.
In order to better implement the invention, the calibration ball 1 for the R-test instrument is used with the R-test instrument and has a diameter of 22 mm.
Other parts of this embodiment are the same as any of embodiments 1-2 described above, and thus are not described again.
The above description is only a preferred embodiment of the present invention, and is not intended to limit the present invention in any way, and all simple modifications and equivalent variations of the above embodiments according to the technical spirit of the present invention are included in the scope of the present invention.

Claims (6)

1. A displacement sensor vector calibration method for an R-test instrument is characterized by comprising the following steps:
step S1: calibration preparation, namely installing an R-test instrument and a calibration ball (1) on a machine tool, determining a machining coordinate system and an R-test instrument measurement coordinate system, moving the calibration ball (1) under the machining coordinate system and the R-test instrument measurement coordinate system, measuring the displacement of the calibration ball (1) through a displacement sensor (2) on the R-test instrument, and recording the measured displacement value;
step S2: constructing a posture calibration model of the displacement sensor (2), setting an axial direction vector of the displacement sensor (2), and establishing a mathematical model between the spherical center coordinates of the displacement sensor (2) and the calibration ball (1);
step S3: solving a vector equation set of the displacement sensor (2), and completing the solution of the vector in the axial direction of the displacement sensor (2) based on a hyperstatic least square method according to the expansion form of the vector equation set;
step S4: calibration verification, namely constructing a sphere center coordinate inverse solution model of the calibration ball (1) according to the posture calibration model of the displacement sensor (2) constructed in the step S2 to complete the conversion and verification of the sphere center coordinate of the calibration ball (1);
the specific steps of constructing the attitude calibration model of the displacement sensor (2) in the step S2 are as follows:
step S2.1: the axial direction vector of the displacement sensor (2) is expressed in an R-test instrument measurement coordinate system as follows:
Figure DEST_PATH_IMAGE001
；
wherein, ViThe axial direction vector of the displacement sensor (2) in an R-test instrument measuring coordinate system is shown, T is the transposition of the vector, i represents the ith displacement sensor (2), i =1,2,3, ui，vi，wiRepresenting axial vectors V of three displacement sensors (2)iIn the R-test instrumentMeasuring spatial coordinates of u, v and w directions in a coordinate system by the device;
step S2.2: according to the fact that the center of the calibration ball (1) is located at the intersection point of the axes of the three displacement sensors (2) in the R-test instrument in the step S1.1, the center of the calibration ball (1) is located at the center of the three displacement sensors (2), and under the measuring coordinate system of the R-test instrument, the initial coordinate of the center of the spherical surface at the top end of the displacement sensor (2) is as follows:
Figure 283512DEST_PATH_IMAGE002
wherein, Pi0Is the initial coordinate of the spherical center of the top of the displacement sensor (2), T is the transpose of the vector, i represents the ith displacement sensor (2), i =1,2,3, ui，vi，wiRepresenting axial vectors V of three displacement sensors (2)iMeasuring space coordinates of u, v and w directions in a coordinate system by using an R-test instrument, wherein R is the radius of a calibration ball (1), and R is the radius of a probe spherical surface of a displacement sensor (2);
step S2.3: sequentially moving the main shaft end calibration ball (1) to different calibration point positions under a processing coordinate system
Figure DEST_PATH_IMAGE003
,
Figure 915482DEST_PATH_IMAGE004
N is the total number of movements, and after each movement is completed, the displacement readings of 3 displacement sensors (2) are
Figure DEST_PATH_IMAGE005
And the change of the spherical center coordinates of the probe spherical surface of the displacement sensor (2) along with the calibration process is obtained as follows:
Figure 426098DEST_PATH_IMAGE006
Figure DEST_PATH_IMAGE007
wherein, PijThe spherical center coordinate of the probe of the displacement sensor (2) is the displacement changed along with the calibration process, dijRepresents the displacement of the i-th displacement sensor (2) at the j-th movement, i =1,2,3, j =1,2, ·, n,
Figure 64889DEST_PATH_IMAGE005
represents the displacement readings, V, of 3 displacement sensors (2)iThe axial direction vector of the displacement sensor (2) in an R-test instrument measuring coordinate system is represented by i, i represents the ith displacement sensor (2), and j represents the movement times of the displacement sensor (2);
step S2.4: during the calibration, the displacement sensor (2) and the calibration ball (1) are always kept in contact state, and the following vector equation system is obtained:
Figure 256836DEST_PATH_IMAGE008
wherein, OjTo mark the position of a point, PijThe displacement of the spherical center coordinates of the probe of the displacement sensor (2) along with the change of the calibration process is represented by i =1,2,3, j =1,2,. the n, R is the radius of the calibration sphere, R is the radius of the probe spherical surface of the displacement sensor (2), i represents the ith displacement sensor (2), and j represents the movement times of the displacement sensor (2);
by combining the position of the calibration point and the vector equation set, any one displacement sensor (2) in the three displacement sensors (2) can be calibrated;
the specific steps of step S3 are:
step S3.1: expanding the vector equation set:
Figure 467281DEST_PATH_IMAGE010
wherein the content of the first and second substances,
Figure DEST_PATH_IMAGE011
represents the displacement readings, x, of 3 displacement sensors (2)j，yj，zjFor indexing the point position OjR is the radius of the calibration sphere, R is the radius of the probe spherical surface of the displacement sensor (2), i represents the ith displacement sensor (2), j represents the moving times of the displacement sensor (2), ui，vi，wiRepresenting axial vectors V of three displacement sensors (2)iMeasuring space coordinates of u, v and w directions in a coordinate system by using an R-test instrument;
step S3.2: the system of vector equations in step S3.1 is further expanded to:
Figure DEST_PATH_IMAGE013
wherein the content of the first and second substances,
Figure 24164DEST_PATH_IMAGE014
represents the displacement readings, x, of 3 displacement sensors (2)j，yj，zjFor indexing the point position OjR is the radius of the calibration sphere, R is the radius of the probe spherical surface of the displacement sensor (2), i represents the ith displacement sensor (2), j represents the moving times of the displacement sensor (2), ui，vi，wiRepresenting axial vectors V of three displacement sensors (2)iMeasuring space coordinates of u, v and w directions in a coordinate system by using an R-test instrument;
since the unit vector of the axial direction vector of each displacement sensor (2) satisfies the principle that the sum of squares is 1, the complementary equation according to the principle that the unit vector satisfies the sum of squares is 1 is:
Figure DEST_PATH_IMAGE015
wherein i represents the i-th displacement sensor (2), i =1,2,3, ui，vi，wiRepresenting axial vectors V of three displacement sensors (2)iMeasuring space coordinates of u, v and w directions in a coordinate system by using an R-test instrument;
let L = R + R, and in combination with the expansion equation and the complementary equation of step S3.2, the vector equation set is rewritten into a matrix form as:
Figure 478148DEST_PATH_IMAGE016
wherein:
Figure DEST_PATH_IMAGE017
Figure 614731DEST_PATH_IMAGE018
Figure DEST_PATH_IMAGE019
the vector V is expressed as:
Figure 204982DEST_PATH_IMAGE020
wherein the vector V is an axial direction vector of the displacement sensor (2), namely an attitude vector of the displacement sensor (2), and the vector V comprises all elements of the axial direction vectors of the three displacement sensors (2), namely the vector V can represent the vector V1、V2、V3Is repeated for each of the three displacement sensors (2)Step S3.2 is carried out to finish the calibration of the three displacement sensors (2), wherein L is the distance between the center of the calibration ball (1) and the center of the contact ball head of the displacement sensor (2);
step S3.3: in step S2.3 and step S2.4, different positions of the calibration point need to be designed
Figure DEST_PATH_IMAGE021
The calibration is carried out, and the setting mode of the calibration point is as follows: the movable range of the X, Y, Z axis is established as a space grid, and boundary points, the middle points of face diagonal lines and the middle points of body diagonal lines on the grid are taken as index points, so that the design requirements on the number of the index points and the accuracy of the index points can be met;
the specific steps of step S4 are:
step S4.1: according to the step S2 of constructing the inverse solution model of the sphere center coordinates of the calibration sphere (1), the vector equation set is re-derived as follows, and the vector equation set is transformed into the form:
Figure 791821DEST_PATH_IMAGE023
wherein i represents the i-th displacement sensor (2), ui，vi，wiRepresenting axial vectors V of three displacement sensors (2)iMeasuring the space coordinates of u, v and w directions in a coordinate system by an R-test instrument,
Figure DEST_PATH_IMAGE024
represents the displacement readings, x, of 3 displacement sensors (2)j，yj，zjFor indexing the point position OjR is the radius of the calibration sphere, and R is the radius of the probe spherical surface of the displacement sensor (2);
because three displacement sensors (2) are arranged to determine the sphere center coordinates of the calibration sphere (1), the vector equation set in the step S4.1 is rewritten into a matrix form:
Figure 483833DEST_PATH_IMAGE025
wherein:
Figure 752003DEST_PATH_IMAGE027
Figure DEST_PATH_IMAGE028
Figure 462339DEST_PATH_IMAGE029
wherein L = R + R, i represents the i-th displacement sensor (2), u1，v1，w1Representing the axial vector V of the first displacement sensor (2)1In the R-test instrument, the spatial coordinates of u, v and w in three directions, u2，v2，w2Represents the axial vector V of the second displacement sensor (2)2In the R-test instrument, the spatial coordinates of u, v and w in three directions, u3，v3，w3Represents the axial direction vector V of the third displacement sensor (2)3Measuring the space coordinates of u, v and w directions in a coordinate system by an R-test instrument,
Figure DEST_PATH_IMAGE030
representing the displacement reading of the first displacement sensor (2),
Figure 829867DEST_PATH_IMAGE031
representing the displacement reading of the second displacement sensor (2),
Figure DEST_PATH_IMAGE032
represents the displacement reading, x, of a third displacement sensor (2)j，yj，zjFor indexing the point position OjThe space coordinate of the calibration sphere (1) can be obtained by performing matrix operation on the space coordinate of the calibration sphere (R) and the radius of the probe spherical surface of the displacement sensor (2):
Figure 992864DEST_PATH_IMAGE033
(Vector)
Figure DEST_PATH_IMAGE034
namely the coordinates (x, y, z) of the center of the calibration ball (1);
step S4.2: and (4) on the basis of the step (S4.1), carrying out the calibration verification process of the R-test instrument, and verifying the accuracy of the calibration result.
2. The method for calibrating the vector of the displacement sensor for the R-test instrument as claimed in claim 1, wherein the step S1 is to perform calibration preparation by the specific steps of:
step S1.1: clamping a calibration ball (1) on a machine tool spindle;
step S1.2: installing an R-test instrument on a machine tool workbench;
step S1.3: after the calibration ball (1) and the R-test instrument are installed, moving the calibration ball (1) at the main shaft end to be right above the R-test instrument;
step S1.4: slowly moving the calibration ball (1) in the Z direction to enable the center of the calibration ball (1) to be located at the intersection point of the axes of the three displacement sensors (2) in the R-test instrument, enabling the displacement values of the three displacement sensors (2) to be consistent, and recording the displacement values of the three displacement sensors (2) as di；i=1,2,3；
Step S1.5: determining X, Y, Z coordinates of the current machine tool coordinate system at the end of the numerical control machine tool as machining coordinate system coordinates, and simultaneously reading d in software of an R-test instrumentiSet as the origin reading d0The intersection point of the axes of the three displacement sensors (2) is determined as the measurement of the R-test instrumentAnd the coordinate system origin enables the directions of the three coordinate systems of the R-test instrument measuring coordinate system, the machining coordinate system and the machine tool coordinate system to be consistent in the calibration state.
3. The method for calibrating the vector of the displacement sensor for the R-test instrument as recited in claim 1, wherein the step S4.1 comprises the following specific steps:
when verification is carried out under the condition that the installation position of the R-test instrument is not changed, the state of the R-test instrument is consistent with the calibration state, and the main shaft end calibration ball (1) is driven to move to the set verification point position
Figure 736829DEST_PATH_IMAGE035
Software matched with the R-test instrument can automatically read the numerical value d of the displacement sensor (2) after reaching the verification pointkKnowing the current displacement sensor (2) reading dkThe origin reading d0The axial vector V of the displacement sensor (2)iI =1,2,3, and substituting into step S4.1 can complete the verification point vector
Figure 36092DEST_PATH_IMAGE034
Calculating (1);
if it is
Figure DEST_PATH_IMAGE036
Otherwise, the step S2 and the step S3 are continued, and the number of calibration points is increased, thereby improving the calibration precision.
4. The method for calibrating the displacement sensor vector for the R-test instrument as claimed in claim 1, wherein when the mounting position of the R-test instrument is remounted, the posture and calibration of the remounted displacement sensor (2) are changed, and the step S4.1 specifically comprises the following steps:
step S4.1.1: firstly, the main shaft end calibration ball (1) is driven to move to the original point position during calibration, and the reading of the displacement sensor (2) and the reading d can be used0The difference between them is judgedSetting the position of the point as a machining coordinate system, wherein the machining coordinate system is consistent with a machine tool coordinate system, but the R-test instrument measurement coordinate system is inconsistent with the machining coordinate system;
step S4.1.2: starting from the origin, the main shaft calibration balls (1) are respectively driven to move in the X, Y direction of a processing coordinate system1、l2(ii) a Respectively obtain the readings of the displacement sensors (2)
Figure 840100DEST_PATH_IMAGE037
、
Figure DEST_PATH_IMAGE038
；
Step S4.1.3: establishing a conversion relation between a measurement coordinate system and a processing coordinate system of the original R-test instrument by using the following formula:
Figure 15692DEST_PATH_IMAGE039
wherein the content of the first and second substances,
Figure 625665DEST_PATH_IMAGE040
Figure DEST_PATH_IMAGE041
wherein the content of the first and second substances,
Figure 310593DEST_PATH_IMAGE042
represents T1、T2Cross-product between two vectors, superscript T representing the transpose of the vector, l1Representing the distance of movement of the calibration ball of the spindle in the X-direction of the machining coordinate system, l2Represents the moving distance of the main shaft calibration ball along the Y direction of the processing coordinate system,
Figure 223185DEST_PATH_IMAGE037
the moving distance of the main shaft calibration ball along the X direction of the processing coordinate system is represented as l1The reading of the time-shift sensor (2),
Figure 236141DEST_PATH_IMAGE038
the moving distance of the main shaft calibration ball along the Y direction of the processing coordinate system is represented as l2Reading of the time displacement sensor (2);
step S4.1.4: then the main shaft end calibration ball (1) is driven to move to the set verification point position
Figure DEST_PATH_IMAGE043
Step S4.1 is substituted to complete the verification point vector
Figure 446542DEST_PATH_IMAGE044
The calculation of (2):
Figure DEST_PATH_IMAGE045
if it is
Figure 251556DEST_PATH_IMAGE046
Otherwise, the step S2 and the step S3 are continued, and the number of calibration points is increased, thereby improving the calibration precision.
5. The method for calibrating the displacement sensor vector for the R-test instrument as recited in claim 1, wherein in the matrix equation established in the step S3.2, when the displacement sensor (2) is a laser displacement sensor, L = R.
6. The method for calibrating the vector of the displacement sensor for the R-test instrument is characterized in that the calibration ball (1) for the R-test instrument is matched with the R-test instrument and has the diameter of 22 mm.
CN202210183482.3A 2022-02-28 2022-02-28 Displacement sensor vector calibration method for R-test instrument Active CN114234877B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202210183482.3A CN114234877B (en) 2022-02-28 2022-02-28 Displacement sensor vector calibration method for R-test instrument

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202210183482.3A CN114234877B (en) 2022-02-28 2022-02-28 Displacement sensor vector calibration method for R-test instrument

Publications (2)

Publication Number Publication Date
CN114234877A CN114234877A (en) 2022-03-25
CN114234877B true CN114234877B (en) 2022-06-14

Family

ID=80748282

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202210183482.3A Active CN114234877B (en) 2022-02-28 2022-02-28 Displacement sensor vector calibration method for R-test instrument

Country Status (1)

Country Link
CN (1) CN114234877B (en)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114782513B (en) * 2022-04-22 2023-11-10 成都飞机工业（集团）有限责任公司 Point laser sensor mounting pose calibration method based on plane
CN115560659B (en) * 2022-10-25 2024-04-02 中国科学院长春光学精密机械与物理研究所 Calibration method of differential capacitance displacement sensor

Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0508686A2 (en) * 1991-04-12 1992-10-14 Renishaw Transducer Systems Limited Calibration device for machine
EP1491287A1 (en) * 2002-03-13 2004-12-29 Unimetrik S.A. Self-centring sensing device
EP2221692A2 (en) * 2007-11-02 2010-08-25 Makino Milling Machine Co. Ltd. Numerically controlled machine tool and numerical control device
CN103365246A (en) * 2012-04-05 2013-10-23 菲迪亚股份公司 Device for error correction for CNC machines
WO2016101289A1 (en) * 2014-12-23 2016-06-30 电子科技大学 Five-axis machine tool cutter posture and cutter tip position error synchronous detection mechanism
CN109032069A (en) * 2018-07-19 2018-12-18 西南交通大学 A kind of contactless R-test measuring instrument sphere centre coordinate calculation method using eddy current displacement sensor
CN112013766A (en) * 2020-08-31 2020-12-01 华中科技大学 Non-contact R-test structural parameter redundancy-free calibration method
CN112247668A (en) * 2020-09-08 2021-01-22 清华大学 Method and device for calibrating error of rotating shaft of numerical control machine tool
CN112405112A (en) * 2020-12-03 2021-02-26 中国工程物理研究院机械制造工艺研究所 Five-axis machine tool linkage error detection device and measurement method
CN113532275A (en) * 2021-07-26 2021-10-22 西安交通大学 Non-contact R-test sphere center coordinate calibration method adopting laser displacement sensor
CN113733102A (en) * 2021-10-08 2021-12-03 厦门大学 Error calibration device and method for industrial robot

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3342328B2 (en) * 1996-11-21 2002-11-05 三菱重工業株式会社 6-axis load device
CN105127840B (en) * 2015-09-08 2017-09-15 清华大学 A kind of five-axis linkage machine tools main tapping attitude angle device and measuring method

Patent Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0508686A2 (en) * 1991-04-12 1992-10-14 Renishaw Transducer Systems Limited Calibration device for machine
EP1491287A1 (en) * 2002-03-13 2004-12-29 Unimetrik S.A. Self-centring sensing device
EP2221692A2 (en) * 2007-11-02 2010-08-25 Makino Milling Machine Co. Ltd. Numerically controlled machine tool and numerical control device
CN103365246A (en) * 2012-04-05 2013-10-23 菲迪亚股份公司 Device for error correction for CNC machines
WO2016101289A1 (en) * 2014-12-23 2016-06-30 电子科技大学 Five-axis machine tool cutter posture and cutter tip position error synchronous detection mechanism
CN109032069A (en) * 2018-07-19 2018-12-18 西南交通大学 A kind of contactless R-test measuring instrument sphere centre coordinate calculation method using eddy current displacement sensor
CN112013766A (en) * 2020-08-31 2020-12-01 华中科技大学 Non-contact R-test structural parameter redundancy-free calibration method
CN112247668A (en) * 2020-09-08 2021-01-22 清华大学 Method and device for calibrating error of rotating shaft of numerical control machine tool
CN112405112A (en) * 2020-12-03 2021-02-26 中国工程物理研究院机械制造工艺研究所 Five-axis machine tool linkage error detection device and measurement method
CN113532275A (en) * 2021-07-26 2021-10-22 西安交通大学 Non-contact R-test sphere center coordinate calibration method adopting laser displacement sensor
CN113733102A (en) * 2021-10-08 2021-12-03 厦门大学 Error calibration device and method for industrial robot

Non-Patent Citations (5)

* Cited by examiner, † Cited by third party
Title
《一种R-test球头球心检测装置结构优化设计方法》;刘大炜 等;《机械工程学报》;20131114;第161-166页 *
《卧式加工中心工作空间热误差检测、建模及辨识方法研究》;蔡翔;《中国优秀博硕士学位论文全文数据库(硕士)工程科技Ⅰ辑》;20190415;第B022-488页 *
《接触式R-test测量仪的标定和球心坐标计算方法研究》;彭炳康 等;《机械科学与技术》;20191106;第1385-1389页 *
《非接触式R-test测量仪的现场标定方法研究》;彭炳康 等;《制造技术与机床》;20191002;第103-106页 *
《非接触式R-test测量仪结构参数优化方法研究》;彭炳康 等;《机床与液压》;20200604;第85-89页 *

Also Published As

Publication number Publication date
CN114234877A (en) 2022-03-25

Similar Documents

Publication Publication Date Title
CN114234877B (en) Displacement sensor vector calibration method for R-test instrument
CN109822574B (en) Industrial robot end six-dimensional force sensor calibration method
Joubair et al. Non-kinematic calibration of a six-axis serial robot using planar constraints
Zhuang et al. Calibration of Stewart platforms and other parallel manipulators by minimizing inverse kinematic residuals
CN111660295A (en) Industrial robot absolute precision calibration system and calibration method
WO2021179460A1 (en) Laser light exit direction calibration method employing standard ball
CN102785129B (en) The online test method of the surface machining accuracy of complex parts
CN109655024A (en) Using the displacement sensor method for calibrating external parameters of spatial transform technique
CN103389038B (en) Laser tracker set the goal multistation measure numerically-controlled machine geometric accuracy detection method
CN107042528A (en) A kind of Kinematic Calibration system and method for industrial robot
CN105136031A (en) Five-axis linkage machine tool rotation shaft geometric error continuous measurement method
CN109238199B (en) Robot rotating shaft kinematic parameter calibration method
Li et al. Accurate compensation method for probe pre-travel errors in on-machine inspections
CN102873586B (en) Fast on-line measuring device for curvature radius of workpiece processed in numerically controlled manner
CN112304218B (en) Tool center point position calibration method and system of industrial robot
CN112069612A (en) Method for evaluating measurement uncertainty of gear measurement center
CN110470223A (en) A kind of three dimensional space coordinate measurement method based on 1D displacement sensor
Wang et al. Calibration technology of the articulated arm flexible CMM
CN111323048B (en) Performance test method and system for single relative attitude measurement machine
CN115164809A (en) Six-axis measurement and error compensation method for blisk
CN110125982B (en) Method for measuring motion trajectory orthogonality of three-degree-of-freedom motion control system of micro-operation robot
JP6933603B2 (en) Machine tool measurement capability evaluation method and program
KR101525677B1 (en) Virtual error estimation simulating method for circular test
CN115371564B (en) Method and system for calibrating relative pose of linear laser sensor and robot flange plate
CN114571506B (en) Gesture alignment method for industrial robot performance measurement

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant