Method for remotely calibrating coordinate measuring machine

Abstract

The invention discloses a method for remotely calibrating a coordinate measuring machine. The method comprises the following steps: constructing a virtual model of the coordinate measuring machine; establishing a motion model of the coordinate measuring machine according to the motion relation among the components of the coordinate measuring machine; installing a fixed gauge block group on the coordinate measuring machine, establishing network connection between the coordinate measuring machine and a remote computer, and obtaining current position information and state information of the coordinate measuring machine; the method comprises the following steps: measuring a gauge block group by using a coordinate measuring machine to obtain measurement data, carrying out virtual-real mapping of a measurement process, state monitoring of the measurement process and data synchronization of the measurement process, obtaining the measurement data in a remote computer, calculating the length of the gauge block group according to the measurement data, and comparing the length with a nominal value. And judging whether the deviation value is within an allowable error range of the coordinate measuring machine or not to realize remote calibration of the coordinate measuring machine. According to the invention, the measurement process and measurement data of the coordinate measuring machine are synchronously mapped to the remote computer, so that remote calibration of the coordinate measuring machine is realized.

Description

Technical Field

[0001] The invention belongs to the field of coordinate measuring machine measurement and calibration, and in particular relates to a method for remotely calibrating a coordinate measuring machine. Background Art

[0002] The purpose of calibrating a coordinate measuring machine is to verify the accuracy of its measurement results to ensure that it can obtain relatively accurate measurement results during use. The general calibration method is generally to use physical standards of different sizes on site to measure the maximum allowable indication error and maximum allowable detection error of the coordinate measuring machine. At present, most of the calibration of coordinate measuring machines is carried out on site. By using physical standards of different sizes, the test results of the maximum allowable indication error and maximum allowable detection error of the coordinate measuring machine are measured. However, the measurement process of on-site calibration is not intuitive enough for remote operators. It is not possible to remotely and conveniently understand the status and stage of the measurement process in real time, and it is not possible to obtain the coordinate measuring machine measurement data in the first place. Summary of the invention

[0003] The object of the present invention is to provide a method for remotely calibrating a coordinate measuring machine, by synchronously mapping the measurement process and measurement data of the coordinate measuring machine to a remote computer, thereby realizing the remote calibration of the coordinate measuring machine.

[0004] In order to achieve the above object, one aspect of the present invention provides a method for remotely calibrating a coordinate measuring machine, comprising:

[0005] Step S1: decomposing the coordinate measuring machine into several components, constructing a geometric model of the coordinate measuring machine, and assembling the components of the coordinate measuring machine to obtain a virtual model of the coordinate measuring machine;

[0006] Step S2: establishing a coordinate measuring machine motion model according to the motion relationship between the various components of the coordinate measuring machine;

[0007] Step S3: installing a fixed gauge block group on the coordinate measuring machine, establishing a network connection between the coordinate measuring machine and a remote computer, and obtaining current position information and status information of the coordinate measuring machine;

[0008] Step S4: Use a coordinate measuring machine to measure the gauge block group to obtain measurement data, perform virtual-real mapping of the measurement process, monitor the state of the measurement process, and synchronize the data of the measurement process. Obtain the measurement data in a remote computer, calculate the length of the gauge block group based on the measurement data, and compare it with the nominal value to determine whether the deviation value is within the allowable error range of the coordinate measuring machine, thereby realizing remote calibration of the coordinate measuring machine.

[0009] Preferably, in step S4, the virtual-to-real mapping of the measurement process includes: constructing the joint movement of the virtual model according to the coordinate measuring machine motion model, including three-axis translation and rotation movement of the measuring head probe, realizing the virtual-to-real mapping of the coordinate measuring machine model, importing the gauge block standard model, and aligning the gauge block standard model with the coordinate measuring machine model, displaying the measuring points as point clouds and measurement trajectories on the gauge block standard model, and realizing the virtual-to-real mapping of the measurement process.

[0010] Preferably, in step S4, the status monitoring of the measurement process includes: acquiring real-time measurement data, transmitting the grating scale data and the measuring head angle data of the coordinate measuring machine to the virtual model of the coordinate measuring machine, and transmitting the collected status data to a remote computer to realize real-time status monitoring of the measurement process.

[0011] Preferably, in step S4, data synchronization of the measurement process includes: while the coordinate measuring machine performs contact measurement on the gauge block in the physical space, the coordinate measuring machine virtual model performs synchronous measurement mapping on the gauge block standard model in the virtual space, and the remote machine computer acquires the measurement data and converts all acquired data points into the gauge block coordinate system through coordinate system conversion.

[0012] Preferably, step S4 also includes: reading the position coordinates passed by the probe during the measurement process, reading the probe trigger signal and the scanning signal from the coordinate measuring machine, and when the probe trigger signal is received, recording and outputting the current probe center point position, and obtaining the gauge block measurement point data before radius compensation; when the probe scanning signal is received, obtaining the gauge block scanning point data before radius compensation, and through the combination of probe signal reading and position coordinate reading, the separation of the probe movement process data and the gauge block measurement point data is achieved.

[0013] Preferably, in step S3, the remote computer scans the controller of the coordinate measuring machine, obtains network connection information of the controller through scanning and connects to it; obtains diagnostic information of the coordinate measuring machine; and obtains current position information and status information of the coordinate measuring machine.

[0014] Preferably, in step S4, a coordinate system is established on the actual gauge block, and the point coordinate values ​​of the two end faces of the gauge block are obtained by measuring and marking with a coordinate measuring machine. The point distance is calculated in the coordinate system, and the distance value is used as the length measurement value of the gauge block.

[0015] According to the method for remotely calibrating a coordinate measuring machine according to the above aspect of the present invention, remote calibration of the coordinate measuring machine is achieved by synchronously mapping the measurement process and measurement data of the coordinate measuring machine to a remote computer. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solution of the present invention, the following briefly introduces the drawings used in the description of the embodiments of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work:

[0017] Figure 1 is a flow chart of a method for remotely calibrating a coordinate measuring machine according to an embodiment of the present invention;

[0018] Figure 2 Schematic diagram of a geometric model of a coordinate measuring machine according to an embodiment of the present invention. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] One embodiment of the present invention provides a method for remotely calibrating a coordinate measuring machine, such as Figure 1 As shown, the method for remotely calibrating a coordinate measuring machine according to an embodiment of the present invention includes steps S1 to S4.

[0021] In step S1 , a virtual geometric model of a coordinate measuring machine is constructed.

[0022] The virtual model of the coordinate measuring machine is constructed based on the analysis of the coordinate measuring machine type architecture. The various components of the coordinate measuring machine and their relationships are studied, starting from the top-level overall structure and gradually subdivided into various sub-components. Each component has its own unique shape and size. Through precise modeling and rendering, its appearance and characteristics can be truly restored in the remote computer.

[0023] Specifically, according to the characteristics of the mechanical structure of the coordinate measuring machine, the hierarchical structure is decomposed in the virtual reality environment, and the coordinate measuring machine is decomposed into several components (sub-objects) to form a hierarchical structure. Figure 2 The complete construction of the coordinate measuring machine geometry model is shown, where 1 is the probe part in the coordinate measuring machine geometry model, 2 is the beam part in the coordinate measuring machine geometry model, 3 is the test table in the coordinate measuring machine geometry model, 4 is the gauge block after abstract processing, and 5 is the base in the coordinate measuring machine geometry model. The XYZ in the figure respectively indicate the directions of the three axes in the coordinate measuring machine measurement process.

[0024] Based on the geometric model, the various components of the coordinate measuring machine are assembled to complete the assembly and simulation work. Using tools such as constraints, moves, and updates, the parts are assembled in the order of the components, and the translation of the three axes and the rotation of the measuring head are added to form the component model. The component model is completed and the virtual model of the coordinate measuring machine is obtained.

[0025] In step S2, after the geometric model is constructed, it is necessary to give the virtual model physical features and constraints, study the motion relationship between the various components of the coordinate measuring machine, and establish a coordinate measurement motion model. In the embodiment of the present invention, the calibration process of the coordinate measuring machine is decomposed into translation and rotation.

[0026] (1) During the motion of the coordinate measuring machine, the translation of point a from the initial position (x1, y1, z1) to the position of point b (x2, y2, z2) can be accurately described by the coordinate transformation matrix:

[0027]

[0028] (2) During the movement of the coordinate measuring machine, the rotation of a point can be described by the initial angle of point a (α1, β1, γ1). When it rotates by Δα, Δβ, Δγ on the X, Y, and Z axes respectively, it will reach a new position b, and its angle becomes (α2, β2, γ2). This can be accurately described by the coordinate transformation matrix:

[0029]

[0030] In step S3 , measurement preparation is performed and data acquisition of the coordinate measuring system is carried out.

[0031] After the coordinate measuring machine is turned on and returned to zero, the gauge block group is installed and fixed. In the actual calibration, the length of the gauge block group is read.

[0032] In the data acquisition of the coordinate measuring system, first, start the client program software of the remote computer and check whether the network connection status with the server is normal. Secondly, scan the coordinate measuring machine controller, obtain the network connection information such as the controller address and port number through scanning, and use the function in the software to connect. Then, call the function in the software to obtain the diagnostic information of the coordinate measuring machine. Finally, use the function in the software to obtain the current position information of the coordinate measuring machine, and record the coordinate value, running speed and other data of each axis into the database for subsequent analysis and processing.

[0033] In step S4, the gauge block group is measured using a coordinate measuring machine to obtain measurement data. Specifically, a coordinate system is established on the gauge block, and the coordinate measuring machine is used to measure and mark points to obtain the point coordinate values ​​of the two end faces of the gauge block. The point distance is calculated in the coordinate system, and the distance value is used as the length measurement value of the gauge block measured at this time. After that, the next gauge block is measured according to this method until the length of the group of gauge blocks is fully measured. After obtaining the measurement data, the length of the gauge block group is calculated in a remote computer to obtain the measurement value of the length of the gauge block group. Repeat three times, and the three measurement results obtained are used as the final measurement results.

[0034] After obtaining the measurement results, the measurement data is acquired in the remote computer by performing virtual-real mapping of the measurement process, state monitoring of the measurement process, and data synchronization of the measurement process.

[0035] (1) Virtual-to-real mapping of the measurement process. A virtual model of the coordinate measuring machine is constructed in a 1:1 ratio according to the structure and dimensions of the coordinate measuring machine of the physical system. The joint motion of the virtual model is constructed in the modeling software according to the motion model of the coordinate measuring machine, including three-axis translation and rotation of the measuring head. The size and shape of the virtual model have editable and reconfigurable functions, and can achieve the same shape change according to the mechanical shape change of the coordinate measuring machine of the physical system, thereby realizing the virtual-to-real mapping of the coordinate measuring machine model. When mapping the gauge block, the gauge block standard model is imported, and the gauge block model is aligned with the coordinate measuring machine model according to the acquired gauge block coordinate system data. The read contact point (measurement point) data is displayed as a point cloud and measurement trajectory on the gauge block standard model to realize the virtual-to-real mapping of the model measurement process.

[0036] (2) Measurement process status monitoring. The transmission architecture of the coordinate measuring machine and remote computer is adopted to obtain real-time data from the measurement software, and the grating scale data and measuring head angle data of the coordinate measuring machine are transmitted to the virtual model of the coordinate measuring machine. The collected ambient temperature, probe pressure data, equipment operation status data, and probe center point trigger data are transmitted to the service interface of the remote computer for recording and display, thus realizing real-time status monitoring of the measurement process.

[0037] (3) Data synchronization during the measurement process. Through the alignment of the coordinate system, the coordinate measuring machine can perform contact measurement on the gauge block in the physical space while the virtual model of the coordinate measuring machine can perform synchronous measurement mapping on the gauge block standard model in the virtual space. Data can be obtained on the remote computer. After the data is obtained, the probe trajectory data points and the measured data points are separated by reading the data under the trigger signal and the scanning signal and the coordinate position of the probe center point data. All the data points obtained are in the machine coordinate system. Through the coordinate system conversion, the data points are converted to the gauge block coordinate system, which is convenient for subsequent data processing and analysis.

[0038] The results of the calibration block are transmitted to the remote computer in real time. The remote computer can read the results of the calibration block of the coordinate measuring machine in real time, and can also read the real-time position and status information of the coordinate measuring machine remotely. The collected data is analyzed and processed to determine whether the deviation between the measured value of the block and the nominal value is within the allowable error range of the coordinate measuring machine. If so, it can be considered that the calibration result has passed.

[0039] In addition, data processing is also performed in step S4 to achieve separation and extraction of the gauge block scanning data and measurement data during the measurement process. The coordinates of the position points passed during the coordinate measurement process are read, including the grating ruler position coordinates during the movement process and the probe center point position coordinates after radius compensation. At the same time, the probe trigger signal and scanning signal can be read from the physical coordinate measuring machine. When the probe trigger signal is received, the current probe center point position is recorded and output to obtain the gauge block measurement point data before radius compensation; when the probe scanning signal is received, the gauge block scanning point data before radius compensation is obtained. The separation of the probe movement process data and the measurement point data on the gauge block is achieved by combining the probe signal reading and the position coordinate reading.

[0040] In summary, the method for remotely calibrating a coordinate measuring machine in an embodiment of the present invention first constructs a virtual model of the coordinate measuring machine, truly restores its appearance and features in a remote computer, then collects data from the coordinate measuring machine and transmits it to the remote computer in real time, uses the measurement data to simulate the synchronous movement of the coordinate measuring machine during the measurement process, realizes visualization of the measurement movement trajectory, collection of measurement data, processing, conversion and evaluation of measurement data, etc., thereby realizing the synchronous mapping of the coordinate measuring machine measurement process and measurement data to the remote computer, and realizing remote calibration of the coordinate measuring machine.

[0041] The method for remotely calibrating a coordinate measuring machine in an embodiment of the present invention relies on real-time synchronous processing of data information, collects data and provides real-time feedback according to the characteristics of the coordinate measuring machine calibration process, solves the problems that could not be achieved in the past remote calibration of coordinate measuring machines, and fills the gap in remote calibration of coordinate measuring machines.

[0042] The above description is only by way of illustration of certain exemplary embodiments of the present invention. It is undoubted that those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the above drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A method for remotely calibrating a coordinate measuring machine, characterized in that: include: Step S1: decomposing the coordinate measuring machine into several components, constructing a geometric model of the coordinate measuring machine, and assembling the components of the coordinate measuring machine to obtain a virtual model of the coordinate measuring machine; Step S2: establishing a coordinate measuring machine motion model according to the motion relationship between the various components of the coordinate measuring machine; Step S3: installing a fixed gauge block group on the coordinate measuring machine, establishing a network connection between the coordinate measuring machine and a remote computer, and obtaining current position information and status information of the coordinate measuring machine; Step S4: Use a coordinate measuring machine to measure the gauge block group to obtain measurement data, perform virtual-real mapping of the measurement process, monitor the state of the measurement process, and synchronize the data of the measurement process. Obtain the measurement data in a remote computer, calculate the length of the gauge block group based on the measurement data, and compare it with the nominal value to determine whether the deviation value is within the allowable error range of the coordinate measuring machine, thereby realizing remote calibration of the coordinate measuring machine.

2. The method according to claim 1, characterized in that In step S4, the virtual-to-real mapping of the measurement process includes: constructing the joint motion of the virtual model according to the coordinate measuring machine motion model, including three-axis translation and rotation motion of the measuring head probe, realizing the virtual-to-real mapping of the coordinate measuring machine model, importing the gauge block standard model, and aligning the gauge block standard model with the coordinate measuring machine model, displaying the measuring points as point clouds and measurement trajectories on the gauge block standard model, and realizing the virtual-to-real mapping of the measurement process.

3. The method according to claim 1 or 2, characterized in that: In step S4, the status monitoring of the measurement process includes: acquiring real-time measurement data, transmitting the grating scale data and the measuring head angle data of the coordinate measuring machine to the virtual model of the coordinate measuring machine, and transmitting the collected status data to the remote computer to realize real-time status monitoring of the measurement process.

4. The method according to claim 1 or 2, characterized in that: In step S4, data synchronization of the measurement process includes: while the coordinate measuring machine performs contact measurement on the gauge block in the physical space, the coordinate measuring machine virtual model performs synchronous measurement mapping on the gauge block standard model in the virtual space, and the remote machine computer obtains the measurement data and converts all the acquired data points into the gauge block coordinate system through coordinate system conversion.

5. The method according to claim 1 or 2, characterized in that: Step S4 also includes: reading the position coordinates passed by the probe during the measurement process, reading the probe trigger signal and scanning signal from the coordinate measuring machine, and when the probe trigger signal is received, recording and outputting the current probe center point position to obtain the gauge block measurement point data before radius compensation; when the probe scanning signal is received, obtaining the gauge block scanning point data before radius compensation, and through the combination of probe signal reading and position coordinate reading, the separation of the probe movement process data and the gauge block measurement point data is achieved.

6. The method according to claim 1 or 2, characterized in that: In step S3, the remote computer scans the controller of the coordinate measuring machine, obtains the network connection information of the controller through scanning and connects to it; obtains the diagnostic information of the coordinate measuring machine; and obtains the current position information and status information of the coordinate measuring machine.

7. The method according to claim 1 or 2, characterized in that: In step S4, a coordinate system is established on the actual gauge block, and the point coordinate values ​​of the two end faces of the gauge block are obtained by measuring and marking with a coordinate measuring machine. The point distance is calculated in the coordinate system, and the distance value is used as the length measurement value of the gauge block.

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