Patent Publication Number: US-2021180932-A1

Title: Control device, measurement system, and measurement method

Description:
RELATED APPLICATIONS 
     The present application claims priority to Japanese Patent Application Number 2019-226291 filed Dec. 16, 2019, the disclosure of which is hereby incorporated by reference herein in its entirety. 
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The present invention relates to a control device, measurement system, and measurement method for an industrial machine. 
     Description of the Related Art 
     Various industrial machines, such as machine tools and industrial robots, are used on a manufacturing floor. The machine tool is one of the industrial machines which machines a workpiece according to a program. To execute a program, a reference position of the workpiece needs to be set in the controller of the machine tool. To detect the reference position of the workpiece, a probe can be mounted on a spindle in the machine tool. The probe detects contact between the probe itself and the workpiece. The controller calculates position and dimensions of the workpiece based on the position where the probe detects contacts. 
     Conventionally, there has been several measurement types, such as “hole measurement”, “point measurement”, “corner measurement”, “tool length measurement”, and “tool diameter measurement”. When one of the measurement types is selected, a measurement program and a measurement operation process corresponding to the selected measurement type are invoked. Necessary operation buttons for the measurements and measurement results are displayed on a display unit, and an operator can set a workpiece coordinate system by operating the probe according to a display screen (see Japanese Patent Application Laid-Open No. 2008-111770, for example). 
     In operating the probe, as described above, the movement direction of the probe is represented by a positive or negative sign and an axis name, such as “+X” or “−Y”. The coordinate system set in the machine tool is invisible so that a user needs to imagine the coordinate system and axis and direction in order to operate the probe. 
     There is another method to set a workpiece coordinate system. In this method, a numerical controller stores templates for measuring a workpiece. An estimated size of the workpiece and the movement direction of the probe are input to the template. The operator moves the probe to a position prescribed by the template and executes the program to automatically measure a reference point of the workpiece. The reference point is used to constitute a workpiece coordinate system. 
     In the automatic measurement of reference points of workpiece coordinate system, the first movement direction of the probe (the movement direction of the probe from the prescribed measurement start position) need to be input to numerical controller. When this is done, the probe may move in an unexpected direction unless the movement direction of the probe is input correctly. 
     SUMMARY OF THE INVENTION 
     In order to overcome these problems, a mechanism is required to facilitate recognition of the movement direction of a probe in an industrial machine. 
     A control device according to one aspect of the present disclosure is a control device for an industrial machine configured to control a probe to measure the position of a workpiece, the control device comprising: a manual operation unit configured to accept a manual operation of the probe from a user; a movement history recording unit configured to record the history of movement of the probe by the manual operation; a measurement program creation unit configured to create a measurement program for the workpiece; a movement direction presentation unit configured to estimate a candidate for the movement direction of the probe based on the history of movement of the probe by the manual operation and present the user with the candidate of the movement direction of the probe to be used in the creation of the measurement program for the workpiece; and an input unit configured to accept the user&#39;s input including the movement direction, the measurement program creation unit being configured to create the measurement program for the workpiece using the user&#39;s input including the moving direction. 
     A measurement system according to one aspect of the present disclosure is a measurement system configured to control a probe to measure a workpiece, the measurement system comprising: a manual operation unit configured to accept a manual operation of the probe from a user; a movement history recording unit configured to record the history of movement of the probe by the manual operation; a measurement program creation unit configured to create a measurement program for the workpiece; a movement direction presentation unit configured to a candidate for the movement direction of the probe based on the history of movement of the probe by the manual operation and present the user with the candidate of the movement direction of the probe to be used in the creation of the measurement program for the workpiece; and an input unit configured to accept the user&#39;s input including the movement direction, the measurement program creation unit being configured to create the measurement program for the workpiece using the user&#39;s input including the movement direction. 
     A measurement method according to one aspect of the present disclosure is a measurement method for controlling a probe to measure a workpiece, the measurement method comprising: accepting a manual operation of the probe from a user; recording the history of movement of the probe by the manual operation; estimating a candidate for the movement direction of the probe based on the movement history of the probe; presenting the user with the candidate of the movement direction of the probe to be used in the creation of the measurement program for the workpiece; accepting the user&#39;s input including the movement direction; and creating the measurement program for the workpiece using the user&#39;s input including the movement direction. 
     According to one aspect of the present invention, the movement direction of a probe in an industrial machine is rendered easily recognizable. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a hardware configuration diagram of a numerical controller according to the present disclosure; 
         FIG. 2  is a block diagram of the numerical controller according to the present disclosure; 
         FIGS. 3A to 3C  are diagrams showing a configuration example of a movement history; 
         FIG. 4  is a diagram showing an example of a screen presenting a candidate for the movement direction of a probe; 
         FIGS. 5A to 5C  are diagrams illustrating an estimation method for the movement direction; and 
         FIG. 6  is a diagram showing workpiece measurement procedure for the numerical controller according to the present disclosure. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The following is a description of a numerical controller  100  as a control device of the present disclosure. A CPU  111  of the numerical controller  100  shown in  FIG. 1  is a processor for generally controlling the numerical controller  100 . The CPU  111  reads out a system program stored in a ROM  112  via a bus  122  and controls the entire numerical controller  100  according to this system program. A RAM  113  is temporarily loaded with temporary calculation data and display data, various data input by a user through an input unit  71 , and the like. 
     A display unit  70  is a monitor or the like attached to the numerical controller  100 . The display unit  70  displays a selection screen for templates  17  (described later), a workpiece data input screen, and the like. 
     The input unit  71  is a keyboard, touch panel, or the like. The touch panel is integral with the display unit  70 . The user operates the input unit  71  to perform input to the screens displayed on the display unit  70 , for example. 
     A non-volatile memory  114  is a memory that is, for example, backed up by a battery (not shown) so that its storage state can be maintained even when the numerical controller  100  is switched off. The non-volatile memory  114  is stored with programs read from external equipment through an interface (not shown), programs input through the display unit  70 , various data (e.g., set parameters acquired from a machine tool  200 ) acquired from various parts of the numerical controller  100 , the machine tool  200 , and the like. The programs and the various data stored in the non-volatile memory  114  may be developed in the RAM  113  during execution and use. Moreover, various system programs are previously written in the ROM  112 . 
     A controller  40  for controlling axes of the machine tool  200  converts an axis movement command from the CPU  111  into a pulse signal and outputs it to a driver  41 . The driver  41  converts the pulse signal into a current, thereby driving a motor  42 . 
     A probe  50  is mounted on a drive unit (spindle, etc.). The motor  42  relatively moves the probe  50  to a workpiece  51 . In the present disclosure, the probe  50  and the workpiece  51  relatively move in the directions of three axes; X-, Y- and Z-axes, however, they may be designed to move in the directions of four or five axes. 
     The probe  50  is a device for detecting the position of an object to be measured. The probe  50  of the present disclosure detects contact with the workpiece  51 . The probe  50  may be designed to detect the position in a noncontact manner using infrared rays or the like. 
     A manual operation unit  10  accepts a manual operation of the motor  42 . In manual operation, the probe  50  moves along the axes of the machine tool  200 . The user operates the probe  50  to locate it in a measurement start position M STR . 
     The numerical controller  100  will be described with reference to  FIG. 2 .  FIG. 2  is a block diagram of the numerical controller  100 . The numerical controller  100  comprises the manual operation unit  10  configured to accept the user&#39;s manual operation, a movement history recording unit  11  configured to record the history of the movement of the probe by the manual operation, a measurement program creation unit  12  configured to create a measurement program for the workpiece  51 , a workpiece data input unit  13  configured to accept input of workpiece data, a movement direction presentation unit  14  configured to present a candidate for the movement direction of the probe  50  to the user, and a workpiece measurement unit  16  configured to measure the workpiece  51  according to the measurement program. 
     The manual operation unit  10  accepts the manual operation of the probe  50 . The operation unit  10  may be a button, handle, touch panel, keyboard, lever, dial, or the like. Types of operation unit  10  are not limited. The probe  50  is mounted on the drive unit of the machine tool  200 . In the manual operation, the probe  50  moves along the axes of the machine tool  200 . In the machine tool  200  of  FIG. 2 , the probe  50  moves in the directions of the three axes; the X-, Y- and Z-axes. The amount of movement of the probe  50  can be calculated based on a command amount output to the controller  40 . The manual operation unit  10  may alternatively be provided on the machine tool  200 . 
     The movement history recording unit  11  records the movement history of the probe  50  in the manual operation into a storage unit  52 . It is to be desired that the movement history of the probe  50  be recorded for each axis of the machine tool  200 . As the movement history of the probe  50 , only the last movement may be recorded, as shown in the table of  FIG. 3A , or all movements of the probe  50  from the start of movement until the end may be recorded, as shown in the table of  FIG. 3B . Only the movement direction may be recorded, as shown in the table of  FIG. 3C . Unintended movements resulted from undesired hand motion or erroneous input may be excluded from the history data to be recorded. In the present disclosure, the movement direction presentation unit  14  sorts out data (described later). 
     The measurement program creation unit  12  comprises the templates  17 , workpiece data input unit  13 , and movement direction presentation unit  14 . Each of the templates  17  is provided for the shape of each workpiece to be measured and each measurement method. 
     The workpiece data input unit  13  displays an input screen corresponding to a selected template  17  on the display unit  70 . This input screen (hereinafter referred to as the workpiece data input screen) accepts input of the dimensions of the workpiece  51 , the movement direction of the probe  50 , the amount of movement of the probe  50 , and the like. 
     In the present disclosure, a candidate for the movement direction of the probe  50  is presented on the workpiece data input screen. The user inputs the movement direction with reference to the presented candidate. 
     The movement direction presentation unit  14  estimates the next movement direction of the probe  50  based on the movement history of the probe  50  having so far been moved by the user and presents the estimated movement direction as a movement direction candidate to the user. The following is a description of an estimation method for the movement direction. In this example to be described, a workpiece  51  with a cuboid shape is measured and an end surface of the workpiece is used as a datum plane to set a workpiece coordinate system. 
     Firstly, a user selects a template. A template is determined on conditions such as the shape of the workpiece  51  is cuboid, the object of measurement is the Y-direction end surface, and the content of measurement is setting of the workpiece coordinate system. The workpiece data input unit  13  displays a workpiece data input screen corresponding to the template. 
       FIG. 4  is an example of the workpiece data input screen. A start position I STR  for manual movement of the probe  50  and a current position I crt  of the probe  50  are displayed on the right-hand side of the workpiece data input screen. On this screen, a character string “movement candidate: ↓ (−Y direction)” is displayed at an upper right portion and a candidate for the movement direction of the probe  50  is presented. 
     An input area  21  for the movement direction of the probe  50  and an input area  22  for the moving distance of the probe  50  exist on the left-hand side of the measurement data input screen. A popup screen  23  is displayed in the movement-direction input area  21  in a superposed manner, and a candidate for the movement direction of the probe, “Notice: to be measured in −Y-axis direction?”, is presented on the popup screen  23 . The user can specify an actual movement direction of the probe  50  with reference to this display. 
     As described above, the numerical controller  100  of the present disclosure presents the candidate for the movement direction. Presenting the candidates helps user to image the coordinate system and prevents operation of the probe  50  in the wrong direction. When the workpiece  51  is set in the machine tool  200 , the numerical controller has no information about the position of the workpiece  510 . Therefore, the numerical controller  100  needs to be taught which direction and how far the probe  50  should be moved to measure the workpiece  51 . The machine coordinate system is not visible for the user who inputs the positional relationship between the workpiece  51  and the probe  50 . This may make it difficult for the user to image the machine coordinate system correctly and cause the user to select a wrong direction. The numerical controller  100  of the present disclosure records the history of the manual movement of the probe  50  and estimates the positional relationship between the probe  50  and the workpiece  51  and presents the result of the estimation to the user, thereby preventing erroneous input at the start of the automatic workpiece measurement. 
     Then, the estimation method for the probe movement direction will be described. In this example, the probe measures the Y-axis end surface of the workpiece  51 , so that only the movement in the Y-axis direction is presented to the user. M STR  is the automatic measurement start position of the probe  50 . To get to the position M STR , user manually moves the probe  50 . Some Paths are shown in  FIGS. 5A to 5C . In the path of  FIG. 5A , the probe  50  is moved in a [1] positive X-axis direction, [2] negative Y-axis direction, [3] positive X-axis direction, [4] negative Y-axis direction, [5] positive X-axis direction, [6] negative Y-axis direction, [7] negative X-axis direction, and [8] negative Y-axis direction to be located in the measurement start position M STR . In the path of  FIG. 5B , the probe  50  is moved in the [1] positive Y-axis direction, [2] positive X-axis direction, [3] negative Y-axis direction, [4] negative X-axis direction, and [5] negative Y-axis direction to be located in the measurement start position M STR . 
     In the path of  FIG. 5C , the probe  50  is moved in the [1] positive X-axis direction, [2] negative Y-axis direction, [3] negative X-axis direction, and [4] positive Y-axis direction to be located in the measurement start position M STR . 
     In the example of  FIG. 5A , the probe  50  is manually moved in the negative direction in all the Y-axis-direction strokes [2], [4], [6] and [8], so that the position of the workpiece  51  can be estimated in the negative Y-axis direction relative to the probe  50 . In the example of  FIG. 5B , the probe  50  greatly moves in the positive Y-axis direction in the stroke [1], while it moves in the negative Y-axis direction in the strokes [3] and [5] thereafter. Since the probe  50  is moved in the negative Y-axis direction in the last movement stroke or final-stage movement strokes, the position of the workpiece  51  can be estimated in the negative Y-axis direction relative to the probe  50 . In the example of  FIG. 5C , the probe  50  is moved in the positive Y-axis direction in the stroke [4] after it is moved in the negative Y-axis direction in the stroke [2]. While the last movement stroke extends in the positive Y-axis direction, the amount of movement therein is small. If the sum of the amounts of movement in the strokes [2] and [4] is obtained, it indicates that the probe  50  is moved in the negative Y-axis direction and it can be considered that the amount of movement in the stroke [2] is compensated for. 
     In this way, it is estimated whether the workpiece  51  is located positive or negative direction in the Y-axis relative to the probe  50 . In the case of  FIG. 5A , the entire direction of manual operation can be a basis of estimation. In the case of  FIG. 5B , the last or final-stage direction of manual operation can be a basis of estimation. In the case of  FIG. 5C , the final-stage direction and amount of manual operation can be a basis of estimation. 
     The movement direction presentation unit  14  estimates the movement direction of the probe  50 , that is, the direction of the workpiece  51  relative to the probe  50 , from the aforementioned entire movement direction, the last or final-stage movement direction, the sum of the movement directions and the amounts of movement, and the like. Candidates for the estimated movement direction are displayed on the workpiece data input screen and the popup screen  23 , as mentioned before. 
     In estimating the movement direction, the movement direction presentation unit  14  excludes data with small amounts of movement from data to be estimated. When the probe  50  is manually moved, the operation of the probe  50  may sometimes fluctuate due to undesired hand motion, delay in reaction, or the like. The movement direction presentation unit  14  may compare the amount of movement with a specified threshold or the like and adopt only operations with large enough to be considered as intentional operations of the user. 
     The measurement program creation unit  12  creates the measurement program for the workpiece  51  based on the template  17  selected by the user and information input to the workpiece data input screen. The workpiece measurement unit  16  measures the workpiece  51  according to the workpiece measurement program. In the aforementioned example of setting of the workpiece coordinate system, the end surface is measured as the datum plane, the datum line of the workpiece  51  is measured, the deviation of the workpiece  51  from the machine coordinate system is compensated for, and the origin of the workpiece coordinate system is set. 
     A measurement method for the workpiece  51  will now be described with reference to the flowchart of  FIG. 6 . 
     First, the workpiece  51  to be measured is mounted on the machine tool  200  (Step S 11 ). After the workpiece  51  is mounted on the machine tool  200 , the start of the measurement of the workpiece  51  is designated. The designation of the measurement start may be replaced with switchover to a manual mode (Step S 12 ). 
     Then, the user manually operates the probe  50  to move to a position close to the workpiece  51  with the manual operation unit  10  (Step S 13 ). As this is done, the movement history recording unit  11  calculates the amount of movement of the manual operation unit  10  and records the movement history of the probe  50  into the storage unit  52  (Step S 14 ). 
     The probe  50  reaches the measurement start position M STR  by the manual operation (Step S 15 ) and the user selects a template  17 . The measurement program creation unit  12  displays a workpiece data input screen corresponding to the template  17  selected by the user (Step S 16 ). The movement direction presentation unit  14  estimates a candidate for the movement direction of the probe  50  (Step S 17 ). The movement direction presentation unit  14  presents the candidate direction for the automatic measurement on the workpiece data input screen (Step S 18 ). In the example of  FIG. 4 , the movement start position I STR  of the probe  50  and the current position I crt  of the probe  50  are presented on the right-hand side of the workpiece data input screen, and the candidate for the movement direction estimated by the movement direction presentation unit  14  is presented by the “movement candidate: (−Y direction)” at the upper right portion of the screen. On the other hand, the input area  21  for the movement direction of the probe  50  and the input area  22  for the distance between the workpiece  51  and the probe  50  exist on the left-hand side of the measurement data input screen. The popup screen  23  is displayed in the movement-direction input area  21  for the movement direction of the probe  50  in a superposed manner, and the candidate for the movement direction of the probe  50 , “presentation content: to be moved in −Y-axis direction?”, is presented on the popup screen  23 . 
     The user inputs the movement direction and the moving amount of the probe  50  while confirming the display of the workpiece data input screen, actual arrangement of the machine tool  200 , and the like (Step S 19 ). The measurement program creation unit  12  creates the measurement program based on data input to the workpiece data input screen, the workpiece dimensions, the movement direction of the probe  50 , and the like (Step S 20 ). The workpiece measurement unit  16  measures the workpiece  51  according to the measurement program created by the measurement program creation unit  12  (Step S 21 ). 
     While the numerical controller  100  for measuring the workpiece  51  and the measurement method for the workpiece  51  have so far been described, the present disclosure is not limited to the above-described example and can be suitably modified and embodied in various forms. 
     While the workpiece coordinate system is set with the end surface in the Y-axis direction regarded as the datum plane in the disclosure described above, for example, the shape of the workpiece  51  is not limited to this and can also be applied to workpieces  51  with other shapes, such as the shapes of a sphere, cylinder, hole, slope, and the like. The measurement part of the workpiece  51  is not limited to end surface and can also be applied to inner surface of a cylinder, hole, and the like. The method of presentation of the movement direction of the probe  50  is not limited to the above-described one. Furthermore, while a machining center with three or more control axes is given as an example of the machine tool of the present disclosure, the number of control axes and the machine type are not limited, for example, a two-axis-controlled lathe can also be applied. 
     In the disclosure described above, the measurement process is executed in the order of the manual probe operation, the selection of template  17 , the input of workpiece data, and the start of automatic measurement. However, the order of processing is not limited to this, and the template  17  may be selected before the manual operation of the probe  50  or the workpiece dimensions may be input at the same time with the selection of the template  17 . The main subject of the present disclosure is to estimate the positional relationship between the workpiece  51  and the probe  50 , based on the history of the movement of the workpiece  51  during the manual operation, and present it to the user. Steps that are unrelated to the main subject may be suitably changed.