Display device

Abstract

A display device capable of automatically determining and displaying a vibration site and a vibration axis by air machining is provided. The display device (1) includes a trajectory error calculation section (13) that calculates time series data of a trajectory error of a tool from a moving trajectory of the tool based on an actual position and a moving trajectory of the tool based on a command position; an amplitude calculation section (14) that performs frequency analysis on the time series data of the trajectory error of the tool to calculate an amplitude of each frequency component; a vibration detection section (15) that detects a frequency component whose amplitude is greater than a prescribed threshold value and detects a position corresponding to the detected frequency component as a vibration site; a vibration axis determination section (16) that determines an axis whose amplitude of the same frequency component as the detected frequency component is greater by performing frequency analysis on time series data of a position deviation of each axis or time series data of a torque command in a time range corresponding to the detected frequency component; and a display section (17) that displays the detected vibration site on the moving trajectory and displays the axis determined as the vibration axis.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a display device. BACKGROUND

[0002] In machining by an industrial machine such as a machine tool, vibration occurs for various reasons. The vibration can become a cause of processing defects such as occurrence of a fold on a machined surface, and thus detection and suppression of the vibration are important in order to improve yield. Detection and evaluation of a vibration site are performed, for example, by an operator visually confirming a machined surface of a workpiece after actual machining, but there is a problem that the visual confirmation is greatly affected by experience value or the like of the operator, and it is difficult to perform an objective evaluation.

[0003] In this regard, detection and evaluation of a vibration site are performed by displaying and operating position data or the like of each axis acquired by actual machining. However, in this case, there is a problem that not only actual machining is required, but also the vibration site needs to be known in advance and it is required to be accustomed to operation of the display device or the like.

[0004] Therefore, a display device capable of visually grasping correspondence of a position on a three-dimensional trajectory of a tool tip with a position on a time axis in time series waveform data of each axis is disclosed (for example, refer to Patent Literature 1). According to the display device, it is possible to intuitively grasp the operation of each axis corresponding to a point on a tool trajectory, and it is possible to efficiently perform adjustment of the operation of the axis.

[0005] PRIOR ART DOCUMENTS

[0006] PATENT LITERATURE

[0007] Patent Literature 1: Japanese Patent Application Publication No. 2011-22688 SUMMARY

[0008] PROBLEMS TO BE SOLVED BY THE INVENTION

[0009] However, in the display device of Patent Literature 1, it is not possible to detect a vibration site on a moving trajectory of a tool and automatically determine a vibration axis that becomes a cause of vibration at the vibration site. This is directly related to start-up of the industrial machine and decrease in time efficiency of evaluation, and thus is an important problem that should be solved.

[0010] An object of the present disclosure is to provide a display device capable of automatically determining and displaying, in advance, a vibration site on a moving trajectory of a tool and a vibration axis that is a cause of vibration in machining by an industrial machine without actual machining.

[0011] SOLUTION TO PROBLEM

[0012] (1) One embodiment of the present disclosure is a display device that displays servo data of a servo control device that controls servo motors that drive each axis of an industrial machine, the display device including: an acquisition unit that acquires each time-series data of an actual position and a command position of the servo motor or a driven body; a movement locus calculation unit that calculates a movement locus of a tool based on the actual position and a movement locus of the tool based on the command position, from each time-series data of the actual position and the command position of the servo motor or the driven body acquired by the acquisition unit; a locus error calculation unit that calculates time-series data of a locus error of the tool, from the movement locus of the tool based on the actual position and the movement locus of the tool based on the command position calculated by the movement locus calculation unit; an amplitude calculation unit that calculates an amplitude of each frequency component by performing frequency analysis on the time-series data of the locus error of the tool calculated by the locus error calculation unit; a vibration detection unit that detects a frequency component whose amplitude calculated by the amplitude calculation unit is greater than a predetermined threshold value, and detects a position corresponding to the detected frequency component as a vibration site; a vibration axis determination unit that determines an axis whose amplitude of the same frequency component as the frequency component detected by the vibration detection unit is large as a vibration axis, by extracting a time range corresponding to the frequency component detected by the vibration detection unit, and performing frequency analysis on time-series data of a position deviation of the axis or time-series data of a torque command in the extracted time range; and a display unit that displays the movement loci calculated by the movement locus calculation unit, and displays the vibration site detected by the vibration detection unit on the movement loci, and displays the axis determined as the vibration axis by the vibration axis determination unit.

[0013] Effects of Invention

[0014] According to one embodiment of the present disclosure, a display device that automatically determines and displays a vibration site on a movement locus of a tool and a vibration axis as a cause of the vibration in advance without actually performing machining in machining performed by an industrial machine can be provided. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 FIG. 1 is a diagram illustrating a structure of a display device according to one embodiment of the present disclosure.

[0016] Figure 2 FIG. 4 is a diagram for explaining frequency analysis in time-series data of a locus error of a tool.

[0017] Figure 3 FIG. 5 is a diagram for explaining frequency analysis in time-series data of a position deviation of each axis.

[0018] Figure 4This is a diagram illustrating a display example of the display device according to the above embodiments.

[0019] Figure 5 This is a flowchart illustrating the display processing procedure in the display device according to the above embodiments. Detailed Implementation

[0020] An embodiment of this disclosure will now be described in detail with reference to the accompanying drawings.

[0021] Figure 1 This is a diagram illustrating the structure of a display device 1 according to one embodiment of this disclosure. Figure 1 As shown, the display device 1 of this embodiment acquires servo data from the control device (servo control device) 3 of the machine tool that controls the motors (servo motors) of each axis 20 of the drive machine tool 2 (axis 1 to axis n), performs the necessary data processing, and displays the data processing results.

[0022] The control device 3 of the machine tool, which is a servo control device, includes a control unit (not shown) composed of a microcomputer or the like, a storage unit including memory such as ROM and RAM, and a transmission and reception unit for transmitting and receiving servo data with the display device 1.

[0023] The display device 1 described in this embodiment is, for example, a computer having a CPU, memory, etc. Figure 1 As shown, the display device 1 includes a data acquisition unit 11, a movement trajectory calculation unit 12, a trajectory error calculation unit 13, an amplitude calculation unit 14, a vibration detection unit 15, a vibration axis determination unit 16, and a display unit 17.

[0024] The data acquisition unit 11 acquires time-series data of the actual position and commanded position of the motor or driven body. Specifically, the data acquisition unit 11 acquires time-series data of the commanded position of the motor or driven body based on position commands generated based on the machining program. Additionally, the data acquisition unit 11 acquires time-series data of the actual position of the motor or driven body based on position feedback from position detectors such as encoders installed on the motors driving each axis 20. Position feedback is acquired by performing idle machining on the machine tool 2. That is, in this embodiment, servo data is acquired in advance from the machine tool control device 3 through idle machining without actually performing machining. Furthermore, the data acquisition unit 11 also acquires tool information such as tool length and tool diameter, torque commands, etc., from the machine tool control device 3.

[0025] The movement locus calculating section 12 calculates a movement locus of the tip of the tool provided in the machine tool 2, i.e., a machining locus. Specifically, the movement locus calculating section 12 calculates a movement locus of the tip of the tool based on actual positions, from time series data of the actual positions of the motor or the driven body acquired by the data acquiring section 11. In addition, the movement locus calculating section 12 calculates a movement locus of the tip of the tool based on command positions, from time series data of the command positions of the motor or the driven body acquired by the data acquiring section 11. Furthermore, in the calculation of each movement locus, tool information acquired by the data acquiring section 11 is also utilized.

[0026] The locus error calculating section 13 calculates time series data of a locus error of the tool provided in the machine tool 2. Specifically, the locus error calculating section 13 calculates time series data of a locus error of the tool, from a difference between a movement locus of the tool based on actual positions calculated by the movement locus calculating section 12 and a movement locus of the tool based on command positions also calculated by the movement locus calculating section 12.

[0027] The amplitude calculating section 14 calculates an amplitude of each frequency component, by performing frequency analysis on the time series data of the locus error of the tool calculated by the locus error calculating section 13. The method of frequency analysis is not particularly limited, as long as it can analyze to what extent a waveform of each frequency component is contained in the data, with respect to the time series data. For example, in the present embodiment, Fourier transform is employed as the method of frequency analysis.

[0028] Figure 2 is a graph for explaining frequency analysis in the time series data of the locus error of the tool. As shown in Figure 2 , by performing Fourier transform on the time series data of the locus error of the tool calculated by the locus error calculating section 13, the time series data of the locus error of the tool is converted into frequency series data. That is, the time series data with the horizontal axis represented by time t is converted into frequency series data with the horizontal axis represented by frequency f. Thereby, it is possible to calculate an amplitude m of each frequency component.

[0029] The vibration detecting section 15 detects a frequency component whose amplitude calculated by the amplitude calculating section 14 is greater than a prescribed threshold value, and detects a position found from a time corresponding to the detected frequency component as a vibration site. The prescribed threshold value is set and stored in advance, based on a relationship between the amplitude of each frequency component and a shape of a machined surface at a position and a time corresponding to each frequency component, for example, based on experimental data or the like.

[0030] The vibration axis determination unit 16 determines a vibration axis that is a cause of vibration at the vibration site detected by the vibration detection unit 15 from each axis 20. As the vibration axis, not limited to one, there can be multiple axes determined as the vibration axis. Specifically, the vibration axis determination unit 16 extracts a time range corresponding to the frequency component detected by the vibration detection unit 15, and performs frequency analysis on the time series data of the positional deviation of each axis or the time series data of the torque command in the extracted time range. Also, the axis with a large amplitude of the frequency component identical to the frequency component detected by the vibration detection unit 15 is determined as the vibration axis.

[0031] Figure 3 is a graph for explaining the frequency analysis in the time series data of the positional deviation of each axis 20. As with the frequency analysis performed by the amplitude calculation unit 14, as a method of the frequency analysis, not particularly limited, for example, Fourier transform is adopted. As shown in Figure 3 , the time series data of the positional deviation is converted into frequency series data by performing Fourier transform on the time series data of the difference between the command position and the position feedback, that is, the positional deviation. That is, the time series data with the horizontal axis represented by time t is converted into frequency series data with the horizontal axis represented by frequency f. This is the same in the case of the time series data of the torque command generated based on the positional deviation.

[0032] Figure 3 In FIG. 6, the data shown in the upper half is the time series data of the positional deviation of each axis before the frequency analysis, and the data shown in the lower half is the frequency series data of the positional deviation of each axis after the frequency analysis. In the example shown in Figure 3 , the frequency series data is obtained by extracting a time range T corresponding to the frequency component F detected in the vibration detection unit 15, and performing frequency analysis on the time series data of the positional deviation of each axis 20 of axis 1 to axis n in the time range T. As such, by performing Fourier transform only on the time range T corresponding to the frequency component F detected as the vibration site, the amount of calculation can be reduced.

[0033] As shown in Figure 3 , when the frequency series data of the positional deviation of each axis 20 after the Fourier transform is compared, a large peak is observed in the frequency series data of axis A, and it is confirmed that the amplitude m is large. Thus, it can be determined that axis A is a vibration axis that is a dominant factor of vibration at the vibration site.

[0034] The display unit 17 displays the movement locus of the tip of the tool based on the actual position calculated by the movement locus calculation unit 12. In addition, the display unit 17 displays the vibration site detected by the vibration detection unit 15 on the movement locus, and displays the axis determined as the vibration axis by the vibration axis determination unit 16.

[0035] In addition, the display section 17 can display the vibration section on the movement trajectory in a manner that changes the display attribute compared to other sections. Thus, the display section 17 can emphasize the display of the vibration section, so that the vibration section can be visually grasped.

[0036] Figure 4 is a diagram illustrating a display example of the display device 1 according to the present embodiment. In the example shown in Figure 4 In the example shown in FIG. 10, on the movement trajectory of the tip of the tool displayed on the display screen 10 by the display section 17, the vibration waveform at the vibration section is emphasized and displayed by a solid arrow and a dashed arrow. In the display screen 10, in addition to the display of the vibration axis, text data of the frequency, the amplitude (maximum amplitude, etc.), and the like corresponding to the vibration axis are displayed. In addition, in the display screen 10, the threshold value of the amplitude used in the vibration detection section 15 can be input. Furthermore, in the display screen 10, a frequency search can be performed by inputting the frequency, and the movement trajectory corresponding to the input frequency can be displayed.

[0037] The process of the display processing of the display device 1 according to the present embodiment having the above-described structure will be described with reference to Figure 5 Figure 5 is a flowchart illustrating the process of the display processing in the display device 1 according to the present embodiment. The display processing starts at an arbitrary timing after the finish of the rough machining of the machine tool 2.

[0038] First, in step S1, the time series data of the position of the motor or the driven body is acquired by the data acquisition section 11. Specifically, the time series data of the actual position and the time series data of the command position of the motor or the driven body are acquired by the data acquisition section 11. After that, the process proceeds to step S2.

[0039] In step S2, the movement trajectory of the tip of the tool possessed by the machine tool 2 is calculated by the movement trajectory calculation section 12. Specifically, the movement trajectory based on the actual position and the movement trajectory based on the command position are calculated by the movement trajectory calculation section 12 from each of the time series data of the actual position and the command position of the motor or the driven body. After that, the process proceeds to step S3.

[0040] In step S3, the time series data of the trajectory error of the tool is calculated by the trajectory error calculation section 13. Specifically, the time series data of the trajectory error of the tool is calculated by the trajectory error calculation section 13 from the difference between the movement trajectory based on the actual position and the movement trajectory based on the command position. After that, the process proceeds to step S4.

[0041] In step S4, the amplitudes of each frequency component are calculated by the amplitude calculation section 14 by performing frequency analysis on the time series data of the trajectory error of the tool. After that, the process proceeds to step S5.

[0042] ​In step S5, the vibration frequency is detected by the vibration detecting section 15. Specifically, the frequency component whose amplitude is greater than a prescribed threshold is detected as the vibration frequency by the vibration detecting section 15 for each frequency component, and the position found from the time corresponding to the detected frequency component is detected as the vibration site. Thereafter, the processing proceeds to step S6.

[0043] In step S6, the time series data of the positional deviation of each axis or the time series data of the torque command is subjected to frequency analysis by the vibration axis determining section 16. In more detail, the time range corresponding to the frequency component detected by the vibration detecting section 15 is extracted, and the time series data of the positional deviation of each axis or the time series data of the torque command is subjected to frequency analysis within the extracted time range. Thereafter, the processing proceeds to step S7.

[0044] In step S7, the axis that becomes the cause of vibration at the vibration site, that is, the vibration axis, is determined by the vibration axis determining section 16. Specifically, the axis whose amplitude of the same frequency component as the frequency component detected by the vibration detecting section 15 is greater is determined as the vibration axis by the vibration axis determining section 16. Thereafter, the processing proceeds to step S8.

[0045] In step S8, the vibration site on the movement locus of the tool and the vibration axis are displayed by the display section 17. Specifically, the movement locus of the tip of the tool based on the actual position is displayed by the display section 17, and the vibration site detected by the vibration detecting section 15 is displayed on the movement locus. Also, the axis determined as the vibration axis by the vibration axis determining section 16 is displayed. The display of the vibration site on the movement locus is emphasized in a manner that changes the display attribute. Thereafter, the present processing ends.

[0046] According to the present embodiment, the following effects are exerted.

[0047] In the display device 1 according to the present embodiment, there are provided: a locus error calculating section 13 that calculates time series data of the locus error of the tool from the movement locus of the tool based on the actual position and the movement locus of the tool based on the command position; an amplitude calculating section 14 that calculates the amplitude of each frequency component by subjecting the time series data of the locus error of the tool to frequency analysis; a vibration detecting section 15 that detects the frequency component whose amplitude is greater than a prescribed threshold for each frequency component, and detects the position corresponding to the detected frequency component as the vibration site; a vibration axis determining section 16 that determines the axis whose amplitude of the same frequency component as the detected frequency component is greater as the vibration axis by subjecting the time series data of the positional deviation of each axis or the time series data of the torque command to frequency analysis within the time range corresponding to the detected frequency component; and a display section 17 that displays the detected vibration site on the movement locus, and displays the axis determined as the vibration axis.

[0048] In a case where a defect is generated on a machined surface due to vibration of a tool in machining, the frequency of vibration at a defective site is important information when investigating the cause of the defect. Therefore, in the present embodiment, by providing the above-described structures, time series data of amplitudes of each frequency component is calculated from time series data of a locus error of a tool based on servo data obtained by a dummy machining without actually performing machining, and a site where vibration is large and its frequency are automatically detected. Thus, it is possible to automatically detect a site where a defect of a machined surface is generated and a frequency of vibration in advance, and thus it is possible to efficiently perform adjustment. In addition, it is possible to determine an axis that is a cause of vibration by comparing a frequency component of a locus error of a site where vibration is large with a frequency component of position data or a torque command of each axis. Furthermore, by displaying a vibration site and a vibration axis together with a moving locus, it is possible for a user to intuitively grasp them, and thus it is possible to greatly improve time efficiency of starting and evaluating an industrial machine.

[0049] In addition, in the present embodiment, a vibration site on a moving locus is displayed in a manner of being emphasized by changing a display attribute. Thus, it is easier for a user to visually grasp, and it is possible to more reliably exert the above-described effects.

[0050] Furthermore, the present disclosure is not limited to the above-described mode, and variations and modifications within a range capable of achieving the object of the present disclosure are also included in the present disclosure.

[0051] For example, in the above-described embodiment, the display device of the present disclosure is applied to a display device that displays servo data of a control device of a machine tool, but is not limited thereto. It can also be applied to a display device that displays servo data of a control device of other industrial machines such as a robot.

[0052] Explanation of Reference Numerals

[0053] 1: display device; 2: machine tool (industrial machine); 3: control device of machine tool (servo control device); 10: display screen; 11: data acquisition unit (acquisition unit); 12: moving locus calculation unit; 13: locus error calculation unit; 14: amplitude calculation unit; 15: vibration detection unit; 16: vibration axis determination unit; 17: display unit; 20: axis.

Claims

1. A display device that displays servo data of a servo control device that controls servo motors that drive each shaft of an industrial machine, the display device comprising: an acquisition section that acquires each time series data of an actual position and a command position of the servo motor or a driven body; a movement locus calculation section that calculates a movement locus of a tool based on the actual position and a movement locus of the tool based on the command position from each time series data of the actual position and the command position of the servo motor or the driven body acquired by the acquisition section; a locus error calculation section that calculates time series data of a locus error of the tool from the movement locus of the tool based on the actual position and the movement locus of the tool based on the command position calculated by the movement locus calculation section; an amplitude calculation section that calculates an amplitude of each frequency component by performing frequency analysis on the time series data of the locus error of the tool calculated by the locus error calculation section; a vibration detection section that detects a frequency component whose amplitude calculated by the amplitude calculation section is greater than a prescribed threshold value, and detects a position corresponding to the detected frequency component as a vibration site; a vibration shaft determination section that determines a shaft whose amplitude of the same frequency component as the frequency component detected by the vibration detection section is large as a vibration shaft by extracting a time range corresponding to the frequency component detected by the vibration detection section, and performing frequency analysis on time series data of a position deviation or time series data of a torque command of the each shaft within the extracted time range; and a display section that displays the movement loci calculated by the movement locus calculation section, displays the vibration sites on the movement loci detected by the vibration detection section, and displays the shaft determined as the vibration shaft by the vibration shaft determination section.

2. The display device according to claim 1, wherein the display section displays the vibration sites on the movement loci in a manner that changes a display attribute. ​ ​ ​ ​ ​ ​ ​ ​ ​

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