CN107085409A - A dynamic error checking method and device for a numerically controlled machine tool - Google Patents

Abstract

The invention discloses a kind of dynamic error method of inspection of Digit Control Machine Tool, including：Data collection steps, first data related to the physical location of the cutter location of the Digit Control Machine Tool and second data related with the offset of the probe of gauge head are obtained from Digit Control Machine Tool；Data processing step, first data and second data are handled, by first data with second data convert into the theoretical Path under workpiece coordinate system, and actual Path is obtained based on the theoretical Path and second data；Analytical procedure, by the relatively theoretical Path and the actual Path, obtains the error between the theoretical Path and the actual Path, obtains the dynamic error of the Digit Control Machine Tool.Digit Control Machine Tool, gauge head and the storage medium examined the invention also discloses a kind of dynamic error verifying attachment of Digit Control Machine Tool, for dynamic error.

Description

A dynamic error checking method and device for a numerically controlled machine tool

technical field

The invention belongs to the technical field of numerical control machine tools, and more specifically relates to a method and device for checking dynamic errors of numerical control machine tools.

Background technique

With the improvement of manufacturing efficiency and precision requirements for CNC machine tools in the manufacturing industry, five-axis machine tools are required to have the dynamic performance of the linkage and cooperation of each servo axis system, and the quality of the dynamic performance will have a significant impact on the quality and processing efficiency of the processed workpiece.

In order to verify whether the dynamic performance of the five-axis machine tool meets the requirements, it is necessary to test the dynamic accuracy of the five-axis machine tool. Scholars at home and abroad have done a lot of research on the inspection of the dynamic accuracy of five-axis machine tools, but there is still a lack of systematic mechanism analysis and authoritative evaluation standards. The sample method based on the cutting of the test piece can partly reflect the dynamic accuracy of the machine tool. At present, the internationally famous machine tool test pieces, such as the NAS979 test piece in the United States, the square pyramid test piece in Japan, and the Mercedes test piece in Germany, can only test the machine tools under static or low speed conditions. The accuracy of the item is powerless for the detection of machine tools under high-speed working conditions. Moreover, the accuracy of some machine tools tested by the above test pieces still cannot meet the expected requirements in practical applications.

Patent CN200710048269.7 discloses a "S"-shaped test piece and its test method for comprehensively testing the accuracy of CNC milling machines." The method of using the test piece to detect the multi-coordinate axis linkage accuracy of the five-axis CNC milling machine is shown in Figure 1. The test piece incorporates the characteristics of aviation thin-wall into the surface of the test piece, which can not only reflect the static accuracy of the five-axis machine tool, but also focus on the dynamic accuracy of the five-axis machine tool. The curvature of the specimen surface changes with the change of the surface shape, and there is an opening and closing angle conversion feature at the corner, and the dynamic error of the five-axis machine tool can be reflected to a certain extent by cutting the "S" piece.

According to the inspection method of the dynamic accuracy of the five-axis machine tool disclosed in the patent CN200710048269.7, as shown in Figure 1, each inspection requires a five-axis machine tool to process an "S" piece, including the entire process from the preparation of blanks, rough machining and finishing. process; then use the three-coordinate measuring instrument to detect the contour error of the processed "S" piece; if the contour error of the "S" piece is unqualified, it is necessary to find the machine tool factors that cause the dynamic error of the five-axis machine tool and adjust the relevant parameters of the machine tool; Then, process the "S" piece completely again until the processed "S" piece meets the accuracy requirements. The inspection time of the dynamic accuracy of such a five-axis machine tool is about one to two days, and some times will be longer. This largely results in a waste of resources such as time, blank material of the test piece, and electric energy, and this method is not convenient for the regular inspection of the dynamic accuracy of the five-axis machine tool and the correction and adjustment of the dynamic performance. When this method verifies whether the processed "S" parts are qualified, it also needs to use three-coordinate measuring instruments and other instruments, which increases the cost of dynamic accuracy inspection of five-axis machine tools in a different direction.

Contents of the invention

In view of the above defects or improvement needs of the prior art, the present invention provides a dynamic error inspection method and device for CNC machine tools, which replaces the feed of the tool by the scanning motion of the probe along the tool track to fit the ruled processing surface of the "S" piece Motion obtains the dynamic error of the five-axis machine tool to test the dynamic accuracy of the five-axis machine tool.

In order to achieve the above object, according to the present invention, there is provided (1) a dynamic error checking method of a CNC machine tool, comprising: a data acquisition step, obtaining from the CNC machine tool the first data relevant to the actual position of the tool position point of the CNC machine tool. data and second data related to the offset of the probe of the measuring head; a data processing step, processing the first data and the second data, and restoring the first data and the second data forming a theoretical tool position trajectory under the workpiece coordinate system, and obtaining an actual tool position trajectory based on the theoretical tool position trajectory and the second data; in the analysis step, by comparing the theoretical tool position trajectory and the actual tool position trajectory, The error between the theoretical tool position trajectory and the actual tool position trajectory is obtained, and the dynamic error of the numerically controlled machine tool is obtained. By adopting the above technical solution, there is no need to actually process workpieces, and there is no need to use instruments such as a three-coordinate measuring instrument. The inspection process is convenient and fast, and the time and resource costs in the inspection process are effectively saved.

(2) According to the dynamic error inspection method described in (1), the first data is obtained by scanning and measuring along the outer contour of the workpiece that has been processed by numerical control.

(3) According to the dynamic error checking method described in (2), the outer contour of the workpiece is scanned and measured with the same feed rate as that of the CNC machining the workpiece and the same motion trajectory as the tool trajectory during machining.

(4) According to the dynamic error inspection method described in (3), the workpiece is an "S" piece, and the tool path is one of the finishing processes of the "S" piece and the base of the "S" piece Closed toolpath with base parallel.

(5) According to the dynamic error inspection method described in (4), when the outer contour of the workpiece is scanned and measured, when there is an unscanned position on the ruled surface of the "S" piece, use The probe of the measuring head performs partial scanning measurement on the site, or touches the site with the probe of the measuring head to perform a test measurement.

(6) According to the dynamic error inspection method described in (5), when it is found that the scanned and measured parts do not meet the requirements of the dynamic accuracy of the CNC machine tool, further inspection and measurement of other unscanned parts is terminated.

(7) According to the dynamic error inspection method described in any one of (1) to (6), the actual tool position trajectory is obtained by adding the theoretical tool position trajectory to the offset data of the probe of the measuring head And get.

(8) According to the dynamic error checking method described in any one of (1) to (6), the first data is related to the actual position of the tool position point of the CNC machine tool under the coordinate system of the CNC machine tool the data; the second data is the data related to the offset of the probe in the probe coordinate system.

Another aspect of the present invention also provides (9) a dynamic error checking device of a numerically controlled machine tool, comprising: a display; a processor capable of performing the following processing: obtaining from the numerically controlled machine tool the actual position of the tool position point of the numerically controlled machine tool related first data and second data related to the offset of the probe of the measuring head; processing the first data and the second data to restore the first data and the second data Form the theoretical tool position trajectory under the workpiece coordinate system, and obtain the actual tool position trajectory based on the theoretical tool position trajectory and the second data; by comparing the theoretical tool position trajectory and the actual tool position trajectory, the described The error between the theoretical tool position trajectory and the actual tool position trajectory is used to obtain the dynamic error of the CNC machine tool.

(10) According to the dynamic error checking device described in (9), the first data is obtained by scanning and measuring along the outer contour of the workpiece that has been processed by numerical control.

(11) According to the dynamic error checking device described in (10), the outer contour of the workpiece is scanned and measured at the same feed rate as that used for CNC machining of the workpiece and the same motion trajectory as that of the tool during machining.

(12) According to the dynamic error checking device described in (9) to (11), the actual tool position trajectory is obtained by adding the theoretical tool position trajectory to the offset data of the probe of the measuring head.

(13) According to the dynamic error checking method described in any one of (9) to (11), the first data is data related to the actual position of the tool position point of the CNC machine tool under the coordinate system of the CNC machine tool ; The second data is data related to the offset of the probe in the probe coordinate system.

The present invention further provides (14) a numerically controlled machine tool that can be used for dynamic error inspection, including: a numerically controlled device, a servo drive device, a signal monitoring and collecting device, a probe, and a spindle; the numerically controlled device is used to control the The operation of the relevant parts of the CNC machine tool; the signal monitoring and acquisition device is connected to the sensing device, and is used to read and write the digital and/or analog signal transmitted by the sensor; the servo drive device is used to receive the signal monitoring and acquisition The digital signal of the device, and output the analog signal to control the movement of the servo motor of the main shaft; the probe is installed on the main shaft to collect the operating data of the main shaft and the The measuring head itself operates data, and transmits the collected data to the signal monitoring and collecting device.

(15) The numerical control machine tool according to (14), further comprising: a UPS power supply for supplying power to the input and output modules of the numerical control device and the signal monitoring and acquisition device.

(16) According to the numerical control machine tool described in (14), the signal monitoring and acquisition device is an analog high-speed data acquisition I/O module based on STM32.

(17) According to the numerical control machine tool described in (14), the probe is a three-dimensional scanning probe, the probe of the probe has a certain range in the three-dimensional direction of space, and the movement of the probe in each direction There will be output of sine and cosine analog signals.

(18) According to the numerical control machine tool described in (14), it is characterized in that the signal monitoring and acquisition device completes the connection between the sensor and the servo drive device and the sensor and the signal monitoring and acquisition device through AD/DA conversion Data communication transmission between input and output modules.

(19) According to the numerically controlled machine tool described in any one of (14) to (18), the numerically controlled device is configured with a measuring head over-range protection module, and when the measuring range of the measuring head reaches the overtravel critical condition, the numerically controlled The device sends an overtravel control signal to control the operation of the corresponding components of the numerical control machine tool.

(20) According to the numerical control machine tool described in (19), when the measuring range of the measuring head reaches the overtravel critical condition, the numerical control device sends an overtravel control signal to control the numerical control machine tool to lock the operation of the spindle.

(21) According to the numerical control machine tool described in any one of (14) to (18), the measuring head has an over-travel protection unit, and when the measuring range of the measuring head reaches the critical condition of over-travel, an over-travel alarm signal is issued. In the above technical solution, when the measuring range of the measuring head reaches the overtravel critical condition, an overtravel alarm signal is sent to remind the user that the measuring head will be overtraveled and necessary measures must be taken to prevent damage to the measuring head or machine failure.

The present invention further provides (22) a measuring head that can be used for dynamic error inspection, including: a measuring head body and a probe; An overtravel signal is issued when overtravel. In the above technical solution, by sending an overtravel signal to the numerical control device, the numerical control device sends an overtravel control signal to control the operation of the corresponding components such as the servo drive device, servo motor or shaft of the above numerical control machine tool, which can automatically and effectively prevent The above-mentioned probe is damaged or the machine is malfunctioning

(23) According to the measuring head described in (22), the probe can scan and measure the outer contour of the workpiece by attaching to the processed surface of the workpiece, and collect the actual position of the tool position point of the CNC machine tool. The offset of the needle itself.

(24) The probe according to (22), wherein the overtravel protection unit sends an overtravel alarm signal when the measuring range of the probe reaches a critical overtravel condition. In the above technical solution, the over-travel protection unit sends out an over-travel alarm signal, which can remind the user to take necessary measures to prevent the above-mentioned measuring head from being damaged or the machine from malfunctioning.

(25) According to the probe described in any one of (22) to (24), the overtravel signal is sent to a numerical control device of a numerically controlled machine tool, and the numerical control device sends an overtravel control signal based on the overtravel signal, Control the operation of the corresponding components of the CNC machine tool.

(26) The probe according to (25), wherein the numerical control device sends an overtravel control signal based on the overtravel signal to control the numerical control machine tool to lock the operation of the spindle.

The present invention further provides (27) a storage medium storing a program enabling at least one processor to perform the following operations: acquiring from a numerically controlled machine tool the first data related to the actual position of the tool position point of the numerically controlled machine tool and the first data related to the measurement The second data related to the offset of the probe of the head; the first data and the second data are processed, and the first data and the second data are restored to the theoretical tool under the workpiece coordinate system position trajectory, and obtain the actual tool position trajectory based on the theoretical tool position trajectory and the second data; by comparing the theoretical tool position trajectory and the actual tool position trajectory, the theoretical tool position trajectory and the actual tool position trajectory are obtained The error between tool position trajectories is used to obtain the dynamic error of the CNC machine tool.

(28) According to the storage medium described in (27), the first data is obtained by scanning and measuring along the outer contour of the workpiece that has been processed by numerical control.

(29) According to the storage medium described in (27), the outer contour of the workpiece is scanned and measured at the same feed rate and the same motion trajectory as the tool trajectory during machining.

(30) According to the storage medium described in any one of (27) to (29), the actual tool position trajectory is obtained by adding the theoretical tool position trajectory to the offset data of the probe of the measuring head .

(31) According to the storage medium described in any one of (27) to (29), the first data is data related to the actual position of the tool position point of the CNC machine tool under the coordinate system of the CNC machine tool; The second data is data related to the offset of the probe in the probe coordinate system.

Generally speaking, compared with the prior art, the above technical solutions conceived by the present invention can achieve the following beneficial effects:

1) The method proposed by the present invention does not need to actually process the "S" piece, and also does not need to use a three-coordinate measuring instrument and other instruments. The inspection process is convenient and quick, and effectively saves time and resource costs in the inspection process.

2) During the dynamic precision inspection process, the tool path of the probe is the track of the tool in the finishing process of the "S" piece, and the probe of the probe fits the surface of the "S" piece, because the "S" piece has been processed by CNC To test the test piece, use the probe instead of the tool to carry out the fitting scanning measurement along the ruled processing surface of this "S" piece at the same feed speed as the tool finishing. The error value obtained can effectively reflect the various aspects of the five-axis machine tool Coordinate axis, servo drive control system and the linkage performance of each servo motor, the synchronously collected data in the machine tool coordinate system is restored to the command tool path in the workpiece coordinate system and the actual tool path with probe offset data through data processing , conveniently and effectively analyze the dynamic error of the five-axis machine tool, verify whether the dynamic accuracy of the five-axis machine tool meets the requirements, and provide a basis for adjusting the linkage performance of the five-axis machine tool.

3) The test proves that the dynamic performance of the five-axis machine tool tested by the five-axis machine tool dynamic accuracy test method according to the present invention is good during use.

Description of drawings

Fig. 1 is a flowchart of an existing method for testing the dynamic accuracy of a five-axis machine tool;

Fig. 2 is a schematic structural diagram of a dynamic error checking system of a numerically controlled machine tool according to an embodiment of the present invention;

3 is a structural block diagram of a data processing device according to an embodiment of the present invention;

4 is a schematic structural view of a measuring head according to an embodiment of the present invention;

Fig. 5 is the flow chart of the dynamic error inspection of the numerical control machine tool of an embodiment of the present invention;

Fig. 6 is a schematic structural view of an "S"-shaped test piece used in an embodiment of the present invention;

Fig. 7 is a schematic diagram of a machine tool dynamic accuracy inspection based on an "S"-shaped inspection specimen in an embodiment of the present invention;

Fig. 8 is a detailed main flowchart of a dynamic error checking method in an embodiment of the present invention;

Fig. 9 is a schematic diagram of a measuring head in an embodiment of the present invention.

detailed description

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not constitute a conflict with each other.

Referring to Figures 1 to 9, the five-axis linkage CNC machine tool dynamic error testing method based on the "S"-shaped test piece, the "S"-shaped test piece 60 used in the present invention is the test piece processed by the patent CN200710048269.7 , the "S"-shaped test piece 60 is formed by numerical control machining, and it is composed of an "S"-shaped ruled surface equal-thickness edge strip 61 and a rectangular base 62, respectively in two different planes The projections of the generated two "S"-shaped curves on the base plane intersect each other, and have open and closed angle forms formed by changing and bending at the intersection. The angle between the ruled surface and the base plane is along its "S" "The trajectory of the line shows a non-uniform change trend,

The dynamic error checking method comprises the following steps:

1. Install the measuring head 19 on the main shaft of the five-axis linkage CNC machine tool, and clamp the "S" piece that has been finished with the CNC machining and meets the set accuracy requirements on the workbench of the five-axis linkage CNC machine tool;

The probe 19 in the present invention is a contact-type three-dimensional scanning probe, preferably using the Renishaw SP2-1 contact-type three-dimensional scanning probe. The Renishaw SP2-1 contact-type three-dimensional scanning probe is mainly composed of four parts, including a motion subsystem, a measurement The subsystem, the overtravel protection unit and the probe 192 are composed, and the schematic diagram of the main body of the measuring head 19 is shown in FIG. 4 . The over-travel protection unit can send an over-travel signal after the displacement of the probe 19 exceeds the range, so as to prevent damage to the probe 19 or machine failure. The critical conditions of overtravel are shown in Table 1.

Table 1 Critical value of probe overtravel

Axis Range/mm Force/N X, Y 18mm (with 100mm tip) 20N～65N Z 5mm min. 400N～600N

For the probe 192 with a weight of 0-10g, the measurement range of each axis of the measuring head 19 is a fixed value, but the measurement range varies with different installation methods, as shown in Table 2.

Table 2 Measuring head range

In this embodiment, the five-axis machine tool and the numerical control system to be tested for dynamic accuracy are the Huazhong 8 CNC system. According to the measurement range of the probe 19, the overtravel protection software module of the probe 19 and the spindle locking mechanism are configured in this system.

The measuring head 19 is connected to the STM32-based analog high-speed data acquisition I/O module through the data connection line, and the module is connected to the numerical control system bus. Because the signal output by the measuring head 19 is a sine-cosine analog signal, it needs to be converted from analog to digital through the above-mentioned I/O module, and the analog signal is converted into a digital signal and transmitted to the numerical control system through the bus.

2. The probe 192 of the measuring head 19 first fits the straight grain processing surface of the "S" piece, and then uses the same feed speed and one of the tool tracks as the data processing "S" piece when machining the "S" piece by CNC With the same motion track, scan and measure a circle along the outer contour of the "S" piece, and at the same time, simultaneously collect the actual position of the tool point of the five-axis linkage CNC machine tool and the offset of the probe 19 probe 192;

In the present invention, the inspection program of the five-axis machine tool operation is a closed track program parallel to the bottom plane of the "S" part base as shown in Figure 2 in the finishing program in the standard program of processing "S" parts, and modify Auxiliary codes such as spindle speed are added to ensure that the feed speed of the probe 19 during scanning measurement is consistent with the feed speed of the tool when processing the "S" piece. When the numerical control system starts to run the inspection program, use the sampling analysis software to synchronously collect the actual position of the tool position point of the five-axis machine tool and the offset of the probe 19 .

The sampling analysis software used in the present invention has functions such as data collection, data storage, data processing, and data analysis. Install the sampling analysis software on the PC, connect the CNC system and the PC with a network cable, and set the IP address, for example, through the communication protocol setting interface, etc., to establish the correct connection between the CNC system and the analysis software.

3. Restore the synchronously collected data to the theoretical tool position trajectory 63 under the workpiece coordinate system through data processing, and obtain the actual tool position trajectory 63 through the theoretical tool position trajectory 63 and the offset data of the probe 19 probe 192, thereby obtaining The error between the theoretical tool position trajectory 63 and the actual tool position trajectory 63 is the dynamic error of the five-axis linkage CNC machine tool.

The present invention collects the machine tool instruction position and the data of the offset of the measuring head 19 and probe 192 in real time during the inspection process, and saves the data locally after the collection is completed. This software can restore the collected machine tool position data in the machine tool coordinate system and the probe 192 offset data in the probe 19 coordinate system to the machine tool command path in the workpiece coordinate system plus the probe 19 offset data. Actual toolpath. Through the comparison of the machine tool instruction tool path and the actual tool path, it is found that the probe 192 of the probe 19 does not touch the "S" part in some places when scanning and measuring the "S" part. For such places, it is necessary to use partial scanning measurement or touch Check the measurement again by touching. If it is found that the place that has been scanned and measured does not meet the requirements of dynamic accuracy, further inspection and measurement can be terminated until the error on a closed curve track of the "S" part is measured. The entire inspection process only takes one to two hours, which greatly shortens the inspection time and saves resource costs.

In addition, in order to make the idea of the present invention clearer, the present invention also provides a dynamic error checking system. FIG. 2 is a schematic structural diagram of the dynamic error checking system of the numerical control machine tool in this embodiment. As shown in FIG. 2 , the dynamic error checking system includes a data processing device 1 and a numerically controlled machine tool 2 , and the data processing device 1 is connected to the numerically controlled machine tool 2 by communication. The above communication connection 3 may include but not limited to wireless or wired network connection, local area network connection, data line connection, bluetooth and other connection methods. For example, by setting an IP address, setting an interface through a communication protocol, etc., a correct connection between the above-mentioned data processing device 1 and the above-mentioned numerically controlled machine tool 2 is established.

The above-mentioned data processing device 1 can be a personal computer (PC), equipped with sampling analysis software, which has functions such as data collection, data storage, data processing, and data analysis. The above-mentioned data processing device 1 acquires data from the above-mentioned numerical control machine tool 2, and uses the above-mentioned sampling analysis software to perform data processing and analysis on the collected data.

Above-mentioned numerical control machine tool 2 comprises numerical control device 11, servo drive device 12, signal monitoring and acquisition device 18, measuring head 19 and main shaft 20 etc., can be Mutual communication connections are made via buses 27 and 28 . Wherein, the above-mentioned numerical control device 11 is a five-axis linkage numerical control system of a numerical control machine tool, which controls the operation of the relevant components of the above-mentioned numerical control machine tool 2; (not shown) feedback signal, and output analog signal to control the movement of the servo motor of the above-mentioned main shaft 20; the above-mentioned signal monitoring and acquisition device 18 is connected with various pressure, position, temperature, voltage and other sensing equipment, mainly used Read and write the digital and/or analog signal transmitted by the sensor, and complete the data communication transmission between the sensor and the above-mentioned servo drive device 12 and the input and output modules of the sensor and the above-mentioned signal monitoring and acquisition device 18 through AD/DA conversion; The measuring head 19 is installed on the above-mentioned main shaft 20 for collecting the running data of the above-mentioned main shaft and the running data of the above-mentioned measuring head 19 itself, and transmitting the collected above-mentioned data to the above-mentioned signal monitoring and collecting device 18 .

The numerical control machine tool 2 may further include a power supply 26 for supplying power to the input and output modules of the numerical control device 11 and the signal monitoring and acquisition device 18 .

In the above embodiment, preferably, the above-mentioned CNC machine tool 2 is a five-axis linkage CNC machine tool, and may also include servo drive devices 13-17 and axes (A, C, X, Y, Z) 21-25. The above-mentioned servo drive devices 13-17 are used to receive the digital signal of the above-mentioned signal monitoring and acquisition device 18, and receive the feedback signal of an external encoder (not shown), and output an analog signal to control the servo motors of the above-mentioned main shafts 21-25 The above-mentioned signal monitoring and collecting device 18 completes the data communication transmission between the sensor and the above-mentioned servo drive devices 13-17 and the input and output modules of the sensor and the above-mentioned signal monitoring and collecting device 18 through AD/DA conversion.

In the above embodiment, preferably, the signal monitoring and acquisition device 18 is an STM32-based analog high-speed data acquisition I/O module, more preferably, a HIO-1000 and/or HIO-1000PULSE signal monitoring and acquisition module.

In the above embodiment, preferably, the above buses 27 and 28 are NCUC-BUS buses. The NCUC-BUS bus is a standardized and open data bus jointly developed by Huazhong CNC and other CNC manufacturers. It is mainly used for digital communication between the serial devices of the CNC machine tool. The NCUC-BUS bus connects the modules in series to achieve signal transmission.

In the above embodiment, preferably, the power supply 26 is a UPS power supply module, which can provide a power-off UPS function and make power-off storage and power-off rollback easier.

In the above embodiment, preferably, the above-mentioned probe 19 is a three-dimensional scanning probe, more preferably, the above-mentioned probe 19 is a Renishaw SP2-1 probe, and the probe of the Renishaw SP2-1 probe is in the three-dimensional direction of space There is a certain range on the probe, and the movement of the probe in each direction will have a sine and cosine analog signal output.

In the above-mentioned embodiment, preferably, in the above-mentioned numerical control device 11, according to the measuring range of the above-mentioned measuring head 19, the above-mentioned measuring head 19 exceeds the range protection software module, and when the displacement of the above-mentioned measuring head 19 exceeds the measuring range (overtravel), control is issued. signal to control the operation of corresponding components such as the servo drive device, servo motor or shaft of the above-mentioned CNC machine tool 2, and prevent the above-mentioned probe 19 from being damaged or machine failure. More preferably, a spindle locking mechanism is also prepared in the above-mentioned numerical control device 11 according to the measuring range of the above-mentioned measuring head 19, and when the displacement of the above-mentioned measuring head 19 exceeds the measuring range (overtravel), a control signal is sent to control the locking of the above-mentioned numerically controlled machine tool 2 The operation of the above-mentioned spindle 20 prevents the damage of the above-mentioned probe 19 or machine failure.

FIG. 3 is a block diagram showing the configuration of the data processing device of the present embodiment. As shown in FIG. 3 , the data processing device 1 can be composed of a personal computer (PC), etc., and mainly consists of a data processing controller 31 , a display 32 and a keyboard 33 including a CPU, ROM and RAM. The data processing controller 31 is mainly composed of a CPU 31a, a ROM 31b, a RAM 31c, a hard disk 31d, a reading device 31e, an input/output interface 31f, a communication interface 31g, and a data output interface 31h. CPU31a, ROM31b, RAM31c, hard disk 31d, reading device 31e, I/O interface 31f, communication interface 31g and data output interface 31h are connected to each other through bus 31i, and can send and receive control signals and control calculation data etc. to each other. The display 32 is used to display the analysis results and/or the restored trajectory diagram of the corresponding workpiece, and the like.

CPU31a can execute the computer program stored in ROM31b and the computer program read into RAM31c.

The ROM 31b is composed of a read-only memory, PROM, EPROM, EEPROM, etc., and stores computer programs executed by the CPU 31a, data used therein, and the like. RAM31c is comprised with SRAM, DRAM, etc., and reads the computer program stored in ROM301b and hard disk 31d. RAM31c can also be used as a work space when CPU31a executes these computer programs.

The hard disk 31d stores various computer programs for the CPU 31a to execute, such as an operating system and application programs, and data for executing the computer programs. The sampling analysis software 7a in this embodiment is also stored in this hard disk 31d.

The reading device 31e is constituted by a floppy drive, a CD-ROM drive, a DVD-ROM drive, etc., and can read computer programs and data stored in the portable storage medium 7 . The sampling analysis software 7a is stored in the portable storage medium 7, and the computer (data processing device) 1 can read the sampling analysis software 7a from the portable storage medium 7 and load it into the hard disk 31d.

The above-mentioned sampling analysis software 7a can not only be provided by the portable storage medium 7, but also can be downloaded from an external machine connected to the electronic communication line (whether wired or wireless) and capable of communicating with the computer (data processing device) 1 through the electronic communication line. For example, the sampling analysis software 7a is stored in the hard disk of the network server, and the computer (data processing device) 1 can access the server, download the sampling analysis software 7a, and load it into the hard disk 31d.

The hard disk 31d is equipped with an operating system providing a graphical user interface such as Windows (registered trademark) produced by Microsoft Corporation of the United States. In the following description, the sampling analysis software 7a of this embodiment is executed on the above-mentioned operating system.

The input/output interface 31f includes serial interfaces such as USB, IEEE1394, and RS-232C, parallel interfaces such as SCSI, IDE, and IEEE1284, and analog signal interfaces including D/A converters and A/D converters. The input/output interface 31f is connected to the keyboard 33, and the user can use the keyboard 33 to directly input data to the computer (data processing device) 1 .

The communication interface 31g may be, for example, an Ethernet (Ethernet, registered trademark) interface. The computer (data processing device) 1 can use a certain communication protocol to transmit data with the above-mentioned numerically controlled machine tool 2 through the communication interface 31g.

The data output interface 31h is connected to a display 32 composed of an LCD or a CRT, and outputs to the display 32 trajectory data restored to a corresponding workpiece received from the CPU 31a. Therefore, the display 32 can display the restored trajectory of the corresponding workpiece according to the input restored trajectory data of the corresponding workpiece.

FIG. 4 is a schematic structural diagram of the measuring head in this embodiment. As shown in FIG. 4 , the above-mentioned probe 9 includes a probe body 191 and a probe 192 . The measuring head body 191 has parts (not shown) such as a motion subsystem, a measurement subsystem, and an overtravel protection unit. Wherein, the above-mentioned over-travel protection unit can send an over-travel signal when the displacement of the above-mentioned probe 19 exceeds the range (over-travel), and send the above-mentioned over-travel signal to the above-mentioned numerical control device 11, and the above-mentioned numerical control device 11 is based on the received The above-mentioned overtravel signal sends an overtravel control signal to control the operation of corresponding components such as the servo drive device, servo motor or shaft of the above-mentioned CNC machine tool 2, and prevent the above-mentioned measuring head 19 from being damaged or machine failure.

For probes 192 with different weights (for example, 0-10 g), the measuring range of each axis of the measuring head 19 is constant. However, different installation methods have different measuring ranges.

In order to prevent damage to the above-mentioned measuring head 19 or machine failure, a critical condition for overtravel can be set. When the measuring range reaches the above-mentioned critical condition for overtravel, the above-mentioned overtravel protection unit will send an overtravel alarm signal to remind the user to take necessary measures to prevent the above-mentioned measurement. The head 19 is damaged or the machine malfunctions.

FIG. 5 is a flow chart of dynamic error checking of the numerically controlled machine tool in this embodiment. As shown in FIG. 5, the probe 19 is mounted on the spindle 20 of the CNC machine tool 2, and the workpiece 60 is mounted on a table (not shown) of the CNC machine tool 2 (step S1). Wherein, the above-mentioned workpiece 60 has been processed by the above-mentioned numerical control machine tool 2 and meets the set precision requirements.

In the present invention, an "S"-shaped test piece 60 (ie, an "S" piece) may be used (see FIG. 6). The above-mentioned "S" piece 60 is formed by numerical control machining. It is composed of an "S"-shaped ruled surface equal-thickness edge strip 61 and a rectangular base 62. Two "S" pieces formed in two different planes respectively The projections of S"-shaped curves on the base plane intersect each other, and have open and closed angle forms formed by changing and bending at the intersection. The angle between the ruled surface and the base plane is along the trajectory of the "S" line It shows a non-uniform change trend.

Returning to FIG. 5 , use the probe 192 of the measuring head 19 to scan and measure the workpiece 60 and collect relevant data synchronously (step S2 ).

Specifically, the above-mentioned numerical control device 11 runs the inspection program to control the above-mentioned servo drive device 12 to drive the servo motor of the above-mentioned main shaft 20, and the probe 192 of the above-mentioned measuring head 19 is first attached to the processing surface of the above-mentioned workpiece, and then the same as when the numerical control is processing the above-mentioned workpiece. The same feed speed and the same motion track as one of the tool tracks when data processing the above-mentioned workpiece, scan and measure a circle along the outer contour of the above-mentioned workpiece, and at the same time, synchronously collect the actual position of the tool position point of the above-mentioned CNC machine tool 2 and The offset of the probe 19 probe 192 mentioned above. Preferably, the above inspection program is a G code.

In the present invention, when using the "S" piece 60, as shown in FIG. The same feed rate during the S" piece 60 and the same motion trajectory 63 as one of the tool tracks during the data processing of the above-mentioned "S" piece 60, scan and measure a circle along the outer contour of the above-mentioned "S" piece 60, and at the same time, Synchronously collect the actual position of the tool point of the CNC machine tool 2 and the offset of the probe 192 of the measuring head 19 .

As shown in FIG. 2 , the above-mentioned measuring head 19 is connected to the above-mentioned signal monitoring and collecting device 18 through a data connection line, and the above-mentioned signal monitoring and collecting device 18 is connected to the above-mentioned numerical control device 11 . The signal output by the measuring head 19 is a sine-cosine analog signal, which needs to be converted from analog to digital by the signal monitoring and collecting device 18 , and the analog signal is converted into a digital signal and transmitted to the numerical control device 11 by the bus 27 .

In the present invention, preferably, the inspection program operated by the numerical control device 11 of the above-mentioned numerical control machine tool 2 is a closed and "S" as shown in Figure 7 in the finishing program in the standard program for processing the "S" piece 60 The program of the trajectory 63 parallel to the bottom plane of the base of the part 60, and the auxiliary codes such as the rotation speed of the above-mentioned spindle 20, can ensure that the feed speed of the above-mentioned probe 19 during scanning measurement is the same as that of the cutting tool when the "S" part 60 is processed. Give speed consistent. When the above-mentioned numerical control device 11 starts to run the inspection program, the above-mentioned sampling analysis software is used to synchronously collect the offset between the actual position of the tool position point of the above-mentioned numerical control machine tool 2 and the above-mentioned probe 19 .

Returning to Fig. 5, the above-mentioned data processing device 1 collects from the above-mentioned CNC machine tool 2 data related to the actual position of the tool position point of the above-mentioned CNC machine tool 2 and the offset of the above-mentioned measuring head 19 probe 192, and runs the above-mentioned sampling analysis software to analyze the above-mentioned The data is processed to obtain the dynamic error of the CNC machine tool 2 (step S3).

Specifically, the above-mentioned data processing device 1 runs the above-mentioned sampling analysis software, and collects from the above-mentioned numerical control device 11 in real time during the inspection process related to the actual position of the tool position point of the above-mentioned numerical control machine tool 2 and the offset of the above-mentioned probe 19 probe 192 The data. After the collection is completed, the above-mentioned data processing device 1 saves the above-mentioned data locally. At the same time, the above-mentioned data processing device 1 operates the above-mentioned sampling analysis software, and combines the data related to the actual position of the tool position point of the above-mentioned numerically controlled machine tool 2 under the machine tool coordinate system that is collected synchronously with the data related to the actual position of the tool point point of the above-mentioned probe 19 under the above-mentioned probe 19 coordinate system. The data related to the offset of the probe 192 is restored to the theoretical tool position trajectory under the workpiece coordinate system through data processing, and based on the theoretical tool position trajectory and the offset data of the probe 192 of the probe 19, the actual Tool position trajectory 63, so as to obtain the error between the theoretical tool position trajectory and the actual tool position trajectory, which is the dynamic error of the above-mentioned CNC machine tool 2.

In the above-mentioned embodiment, preferably, the above-mentioned actual tool-position trajectory 63 is obtained by adding the above-mentioned theoretical tool-position trajectory to the offset data of the probe 192 of the measuring head 19 .

In the present invention, by comparing the theoretical tool position trajectory with the actual tool position trajectory, it is found that the probe 192 of the above-mentioned measuring head 19 does not touch the above-mentioned workpiece in some places when scanning and measuring the above-mentioned workpiece. For such places, local scanning is required. Check and measure again by measuring or touching. If it is found that the place that has been scanned and measured does not meet the requirements of dynamic accuracy, further inspection and measurement can be terminated until the error on a closed curved track of the above-mentioned workpiece is measured. . The entire inspection process only takes one to two hours, which greatly shortens the inspection time and saves resource costs.

Those skilled in the art can easily understand that the above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention, All should be included within the protection scope of the present invention.

Claims (31)

1. A dynamic error checking method of a numerically controlled machine tool, comprising: The data acquisition step is to obtain from the CNC machine tool first data related to the actual position of the tool point of the CNC machine tool and second data related to the offset of the probe of the measuring head; A data processing step, processing the first data and the second data, restoring the first data and the second data to a theoretical tool position trajectory in the workpiece coordinate system, and based on the theoretical tool position track and the second data to obtain the actual tool position track; The analysis step is to obtain the error between the theoretical tool position trajectory and the actual tool position trajectory by comparing the theoretical tool position trajectory with the actual tool position trajectory, and obtain the dynamic error of the CNC machine tool. 2. dynamic error checking method according to claim 1, is characterized in that, The first data is obtained by scanning and measuring along the outer contour of the CNC machined workpiece. 3. dynamic error checking method according to claim 2, is characterized in that, The outer contour of the workpiece is scanned and measured at the same feed speed and the same motion trajectory as the tool trajectory during machining. 4. dynamic error checking method according to claim 3, is characterized in that, The workpiece is an "S" piece, and the tool path is a closed tool path parallel to the bottom surface of the base of the "S" piece during finishing of the "S" piece. 5. The dynamic error inspection method according to claim 4, characterized in that, when the outer contour of the workpiece is scanned and measured, when there is an unscanned position on the ruled surface of the "S" piece , then use the probe of the measuring head to perform partial scanning measurement on the part, or touch the position with the probe of the measuring head to perform a test measurement. 6. The dynamic error checking method according to claim 5, characterized in that, when it is found that the scanned and measured position does not meet the requirements of the dynamic accuracy of the numerical control machine tool, then the further checking and measuring of other unscanned positions is terminated. 7. The dynamic error checking method according to any one of claims 1 to 6, wherein the actual tool position trajectory is obtained by adding the theoretical tool position trajectory to the offset of the probe of the measuring head data obtained. 8. The dynamic error checking method according to any one of claims 1 to 6, wherein the first data is the actual position of the tool position point of the numerically controlled machine tool under the coordinate system of the numerically controlled machine tool Related data; the second data is data related to the offset of the probe in the probe coordinate system. 9. A dynamic error checking device for a numerically controlled machine tool, comprising: monitor; Processor capable of the following processing: Obtaining from the CNC machine tool first data related to the actual position of the tool point of the CNC machine tool and second data related to the offset of the probe of the measuring head; Processing the first data and the second data, restoring the first data and the second data to a theoretical tool position trajectory in the workpiece coordinate system, and based on the theoretical tool position trajectory and the The second data obtains the actual tool position trajectory; By comparing the theoretical tool position trajectory and the actual tool position trajectory, the error between the theoretical tool position trajectory and the actual tool position trajectory is obtained, and the dynamic error of the numerical control machine tool is obtained. 10. The dynamic error checking device according to claim 9, characterized in that, The first data is obtained by scanning and measuring along the outer contour of the CNC machined workpiece. 11. The dynamic error checking device according to claim 10, characterized in that, The outer contour of the workpiece is scanned and measured at the same feed speed and the same motion trajectory as the tool trajectory during machining. 12. The dynamic error inspection device according to claims 9-11, characterized in that the actual tool position trajectory is obtained by adding the theoretical tool position trajectory to the offset data of the probe of the measuring head . 13. The dynamic error checking method according to any one of claims 9 to 11, wherein the first data is related to the actual position of the tool position point of the numerically controlled machine tool under the coordinate system of the numerically controlled machine tool data; the second data is data related to the offset of the probe in the probe coordinate system. 14. A numerical control machine tool that can be used for dynamic error inspection, including: numerical control device, servo drive device, signal monitoring and acquisition device, probe and spindle; The numerical control device is used to control the operation of related components of the numerical control machine tool; The signal monitoring and acquisition device is connected to the sensing equipment, and is used for reading and writing digital and/or analog signals transmitted by the sensor; The servo drive device is used to receive the digital signal from the signal monitoring and acquisition device, and output the analog signal to control the movement of the servo motor of the main shaft; The measuring head is installed on the main shaft to collect the running data of the main shaft and the running data of the measuring head itself, and transmit the collected data to the signal monitoring and collecting device. 15. The numerical control machine tool according to claim 14, further comprising: a UPS power supply for supplying power to the input and output modules of the numerical control device and the signal monitoring and acquisition device. 16. The numerical control machine tool according to claim 14, wherein the signal monitoring and acquisition device is an analog high-speed data acquisition I/O module based on STM32. 17. The numerically controlled machine tool according to claim 14, wherein the probe is a three-dimensional scanning probe, the probes of the probe have a certain range in the three-dimensional direction of space, each of the probes The direction of movement will have the output of sine and cosine analog signals. 18. The numerical control machine tool according to claim 14, characterized in that, the signal monitoring and acquisition device completes the input of the sensor and the servo driver and the sensor and the signal monitoring and acquisition device through AD/DA conversion Data communication transmission between output modules. 19. The numerical control machine tool according to any one of claims 14-18, characterized in that, the numerical control device is configured with a measuring head over-range protection module, and when the measuring range of the measuring head reaches the overtravel critical condition, the The numerical control device sends an overtravel control signal to control the operation of the corresponding components of the numerical control machine tool. 20. The numerical control machine tool according to claim 19, characterized in that, when the measuring range of the probe reaches the overtravel critical condition, the numerical control device sends an overtravel control signal to control the numerical control machine tool to lock the spindle running. 21. The numerically controlled machine tool according to any one of claims 14-18, characterized in that the measuring head has an overtravel protection unit, and when the measuring range of the measuring head reaches the overtravel critical condition, an overtravel alarm signal is sent . 22. A measuring head that can be used for dynamic error inspection, comprising: a measuring head body and a probe; the measuring head body has an overtravel protection unit that can send an overtravel signal when the displacement of the measuring head exceeds the travel distance. 23. The measuring head according to claim 22, characterized in that, the probe can scan and measure the outer contour of the workpiece by attaching to the processed surface of the workpiece, and collect the actual position of the tool position point of the CNC machine tool The offset of the probe itself. 24. The probe according to claim 22, wherein the overtravel protection unit sends an overtravel alarm signal when the measuring range of the probe reaches a critical overtravel condition. 25. The measuring head according to any one of claims 22-24, characterized in that, the overtravel signal is sent to a numerical control device of a numerically controlled machine tool, and the numerical control device sends an overtravel control signal based on the overtravel signal , to control the operation of corresponding components of the numerical control machine tool. 26. The probe according to claim 25, wherein the numerical control device sends an overtravel control signal based on the overtravel signal to control the numerical control machine tool to lock the operation of the spindle. 27. A storage medium, storing a program enabling at least one processor to: Obtaining from the CNC machine tool first data related to the actual position of the tool point of the CNC machine tool and second data related to the offset of the probe of the measuring head; Processing the first data and the second data, restoring the first data and the second data to a theoretical tool position trajectory in the workpiece coordinate system, and based on the theoretical tool position trajectory and the The second data obtains the actual tool position trajectory; By comparing the theoretical tool position trajectory and the actual tool position trajectory, the error between the theoretical tool position trajectory and the actual tool position trajectory is obtained, and the dynamic error of the numerical control machine tool is obtained. 28. The storage medium according to claim 27, wherein: The first data is obtained by scanning and measuring along the outer contour of the CNC machined workpiece. 29. The storage medium according to claim 27, wherein, The outer contour of the workpiece is scanned and measured at the same feed speed and the same motion trajectory as the tool trajectory during machining. 30. The storage medium according to any one of claims 27-29, characterized in that the actual tool position trajectory is obtained by adding the theoretical tool position trajectory to the offset data of the probe of the measuring head get. 31. The storage medium according to any one of claims 27-29, wherein the first data is data related to the actual position of the tool point of the CNC machine tool under the coordinate system of the CNC machine tool; The second data is data related to the offset of the probe in the probe coordinate system.