Robot-equipped moving device

Abstract

To set accurately the position of a robot performing operation working on an object in a machine tool.SOLUTION: When a second identification position is inside a prescribed range from a second device position, the position of a hand part is adjusted, and when the second identification position is outside the prescribed range from the second device position, a move part is moved to thereby adjust the position of the move part, based on the second identification position which is a position of an identification figure when an identification image is imaged by a camera, on the second device position different from a first device position.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a robot-mounted mobile device that includes a robot having a hand unit that acts on an object, and a mobile unit that mounts the robot and moves it to a predetermined work position. [Background technology]

[0002] A known example of a conventional system using the above-described robot-mounted moving device is the system disclosed in Japanese Patent Laid-Open Publication No. 2017-132002 (Patent Document 1). In this system, an automated guided vehicle equipped with a robot moves to a work position set for a machine tool, and at this work position, the robot performs work such as attaching and detaching a workpiece to and from the machine tool.

[0003] In such a system, a single robot moved by an automatic guided vehicle can perform tasks such as attaching and detaching workpieces to multiple machine tools, which increases the degree of freedom in the layout of the machine tools compared to when robots are fixedly installed relative to the machine tools, making it possible to set the layout of the machine tools in a way that can further improve production efficiency.Furthermore, compared to conventional systems in which robots are installed in a fixed state, a single robot can perform tasks on a larger number of machine tools, which reduces equipment costs.

[0004] On the other hand, because an automated guided vehicle is self-propelled using wheels, the positioning accuracy with which it stops at the work position is not necessarily high.

[0005] Conventionally, a position correction method such as that disclosed in Japanese Patent Laid-Open No. 2016-221622 (Patent Document 2) has been known as a technology for correcting the working posture of a robot that is disposed in a fixed state. Specifically, this position correction method involves arranging a visual target consisting of two calibration markers on the outer surface of a machine tool, capturing an image of the visual target with a camera attached to a movable part of the robot, measuring the relative positional relationship between the robot and the machine tool based on the obtained image and the position and posture of the camera, and correcting the working posture of the robot based on the measured positional relationship.

[0006] In the case of a multi-joint robot, the position of the operating unit (end effector) provided at the tip of the robot's arm is determined as the cumulative result of the postures of each arm that moves due to the rotation of the motor that constitutes each joint. Since there is a structural limit to the rotation angle of each motor, depending on the posture of each arm, there will be a point, a singular point, where the operating unit cannot move any further in a certain direction. For example, if the arms are aligned in a straight line, the operating unit cannot move in the direction of the extension line. Furthermore, when two or more movable axes are aligned in a straight line, there will be a direction in which the operating unit cannot move.

[0007] Therefore, in automatic operation, when correcting the working posture of the robot when the automated guided vehicle is positioned at the working position, if the positioning error of the automated guided vehicle exceeds the movable range of the action part limited by the singular point, the working posture of the robot cannot be corrected, and conventionally the system would enter an alarm state and stop.

[0008] This point will be explained more specifically with reference to Figures 10 and 11. In Figures 10 and 11, it is assumed that the automated guided vehicle moves on the X-Y plane, and when the automated guided vehicle is positioned at the work position during teaching, the position (target position) of the tip of the operating part of the robot (robot tip) on a plane parallel to the X-Y plane is denoted as Pt, and when the automated guided vehicle is positioned at the work position during automatic driving, the position (actual operating position) of the robot tip on a plane parallel to the X-Y plane is denoted as Pa. Furthermore, the positioning errors of the automated guided vehicle are denoted as ΔXe and ΔYe, and the movable distances of the robot tip in the X- and Y-axis directions from the actual operating position Pa are denoted as Xc and Yc.

[0009] For example, as shown in FIG. 10, if both of the positioning errors ΔXe and ΔYe of the automated guided vehicle are smaller than the movable distances Xc and Yc in the X-axis and Y-axis directions of the robot tip part relative to the actual operation position Pa, in other words, if the target position Pt, to which the robot tip part should be moved by correction, is within the movable area of ​​the robot tip part indicated by the two-dot chain line, then the actual operation position Pa of the robot tip part can be corrected to the target position Pt (see the dashed arrow).

[0010] On the other hand, as shown in FIG. 11, if at least one of the positioning errors ΔXe, ΔYe of the automated guided vehicle exceeds the movable distances Xc, Yc in the X-axis and Y-axis directions of the robot tip end based on the actual operating position Pa (ΔXe>Xc in the example shown in FIG. 11), that is, if the target position Pt to which the robot tip end should be moved by correction is outside the movable area of ​​the robot tip end indicated by the two-dot chain line, then the actual operating position Pa of the robot tip end cannot be corrected to the target position Pt (see the dashed arrow). [Prior art documents] [Patent documents]

[0011] [Patent Document 1] Japanese Patent Application Publication No. 2017-132002 [Patent Document 2] Japanese Patent Application Laid-Open No. 2016-221622 Summary of the Invention [Problem to be solved by the invention]

[0012] If the above-described correction is not possible and the system enters an alarm state and stops, it is necessary to return the moving unit and robot to their initial positions and then restart the system. Also, if alarms occur frequently, it is necessary to take measures such as resetting the robot position and the moving unit's movement position through teaching operations. However, taking such measures reduces the system's availability. Therefore, there is a demand for improving the positional accuracy of robots that perform operations that act on objects within machine tools. [Means for solving the problem]

[0013] Therefore, the present invention provides a robot-mounted moving device, a system positioning control method, and the like as set forth in the claims. [Effects of the Invention]

[0014] The present invention can improve the positional accuracy of a robot that performs an operation acting on an object within a machine tool. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a plan view showing a schematic configuration of a system according to an embodiment of the present invention. [Figure 2] 1 is a block diagram showing the configuration of a system according to an embodiment of the present invention. [Figure 3] FIG. 2 is a perspective view showing a moving unit and a robot according to the present embodiment. [Figure 4] FIG. 2 is an explanatory diagram regarding the imaging posture of the robot according to the embodiment. [Figure 5] FIG. 2 is an explanatory diagram showing an identification figure according to the embodiment. [Figure 6] 3 is an explanatory diagram relating to control of the robot-mounted moving device in this embodiment. FIG. [Figure 7] 3 is an explanatory diagram relating to control of the robot-mounted moving device in this embodiment. FIG. [Figure 8] 3 is an explanatory diagram relating to control of the robot-mounted moving device in this embodiment. FIG. [Figure 9] FIG. 2 is an explanatory diagram for explaining control in the present embodiment. [Figure 10] FIG. 10 is an explanatory diagram for explaining a setting method. [Figure 11] FIG. 10 is an explanatory diagram for explaining a setting method. [Figure 12] FIG. 4 is an explanatory diagram for explaining a correction amount calculation method in the present embodiment. [Figure 13] 1 is a plan view showing a schematic configuration of a system according to an embodiment of the present invention. [Figure 14] 10 is a perspective view showing an example of a captured image of an identification graphic according to the present embodiment. FIG. [Figure 15] FIG. 10 is an explanatory diagram showing a modified example in which an identification graphic is arranged in a machine tool. [Figure 16] 10 is an explanatory diagram for explaining processing in a control unit when an image of an identification graphic is captured. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0016] Hereinafter, specific embodiments of the present invention will be described with reference to the drawings.

[0017] <<Embodiment 1>> As shown in Figures 1 and 2, the system 1 of this example includes a first machine tool 10A, a second machine tool 10B, and a third machine tool 10C (hereinafter, these may be collectively referred to as machine tools 10) having the same configuration, a material stocker 20 and a product stocker 21 as peripheral devices, an automated guided vehicle 35 which is an example of a moving part, a robot 25 mounted on this automated guided vehicle 35, a camera 31 attached to the robot 25, a hand part of the robot 25, and a control device 40 which controls the automated guided vehicle 35. In this embodiment, the robot-mounted moving device is made up of the automatic guided vehicle 35, the robot 25, the camera 31, and the control device 40, but is not limited to this configuration. The robot-mounted moving device of this embodiment only needs to have at least the camera, the robot, a control unit that controls the position of the robot's hand unit, and a movable moving unit.

[0018] As shown in Fig. 4, machine tool 10 is a so-called horizontal NC (numerically controlled) lathe equipped with a spindle 11 to which a chuck 12 for gripping workpiece W1 (W2) is attached, and is capable of performing turning on workpiece W1 (W2). Also, a tool presetter 13 equipped with a contact 14 and a support bar 15 for supporting it is provided near the spindle 11, and this support bar 15 is provided so as to be able to advance and retreat with respect to the machining area along the axis of the spindle 11, and a ceramic display plate 16 is provided on the end surface facing the machining area, and the identification figure shown in Fig. 5 is drawn on this display plate 16.

[0019] Furthermore, the identification symbol is preferably imaged by camera 31 when it is located within the machining area of ​​machine tool 10. For this reason, coolant, machining debris, and the like may adhere to the identification symbol, which may make it impossible to recognize the position of the identification symbol from image data containing the identification symbol. Therefore, robot 25 may be provided with cleaning means 32 (shown by a dashed line in FIG. 4 ), such as an air blower or rubber brush, to clean display board 16 containing the identification symbol. Furthermore, rather than providing cleaning means 32 on robot 25, the cleaning means may be provided on machine tool 10. For example, vibration generating means, such as ultrasonic vibration generating means comprised of a piezoelectric element, may be provided on the back of display board 16 to vibrate display board 16 containing the identification symbol, thereby shaking off any foreign matter adhering to the surface of display board 16 or the surface of the identification symbol.

[0020] In this embodiment, the display plate 16 is installed horizontally, and therefore the identification graphic is parallel to the horizontal plane. Also, while Fig. 4 shows a state in which the support bar 15 and contactor 14 have advanced into the processing area, when the support bar 15 and contactor 14 retract and the contactor 14 and display plate 16 are stored in the storage area, the shutter 17 is closed, and the contactor 14 and display plate 16 are isolated from the processing area. Note that the display plate 16 can also be installed parallel to a vertical plane, and as an example of such an arrangement, the dashed line in Fig. 1 shows an example in which the display plate 16 is positioned in front of the robot 25.

[0021] The identification figure in this example has a matrix structure in which a plurality of square pixels are arranged two-dimensionally, and each pixel is displayed in white or black. In FIG. 5, black pixels are shaded. Such identification figures include those called AR markers and April Tags. If the identification figure is small, a lens may be provided on the identification figure so that an enlarged image can be captured by a camera 31, which will be described later.

[0022] The material stocker 20 is disposed to the left of the first machine tool 10A in Fig. 1 and is a device for stocking a plurality of materials (unmachined workpieces W1) to be machined by the first machine tool 10A. The product stocker 21 is disposed to the right of the third machine tool 10C in Fig. 1 and is a device for stocking a plurality of finished or semi-finished products (machined workpieces W2) machined by the third machine tool 10C.

[0023] 1, an automated guided vehicle 35, which is an example of a moving unit, has a robot 25 mounted on a mounting surface 36, which is its upper surface, and is also provided with an operator-portable operation panel 37. The operation panel 37 is equipped with an input / output unit for inputting and outputting data, an operation unit for manually operating the automated guided vehicle 35 and robot 25, a display capable of displaying information on a screen, and the like.

[0024] Furthermore, the automated guided vehicle 35 is equipped with a sensor (for example, a distance measurement sensor using laser light) that can recognize its own position within the factory, and under the control of the control device 40, it can travel without track within the horizontal X-Y plane within the factory, including the area where the first machine tool 10A, the second machine tool 10B, the third machine tool 10C, the material stocker 20, and the product stocker 21 are arranged. The robot-mounted mobile device of this example passes through each of the work positions set for the first machine tool 10A, the second machine tool 10B, the third machine tool 10C, the material stocker 20, and the product stocker 21.

[0025] 1 and 3, the robot 25 of this embodiment is an articulated robot equipped with three arms: a first arm 26, a second arm 27, and a third arm 28. In addition, the robot 25 has a hand 29 attached to the tip of the third arm 28 as an end effector (action unit), and a camera 31 attached via a support bar 30. The hand 29 and camera 31 are moved within a three-dimensional space defined by horizontal X- and Y-axes and a vertical Z-axis perpendicular to these axes. However, the robot 25 is not limited to the above-described configuration. For example, the robot may have at least (i) a camera, (ii) a hand unit for grasping an object such as a workpiece or a tool, (iii) a second arm unit to which the hand unit is movably connected, and (iv) a first arm unit to which the second arm unit is movably connected. In this embodiment, the first arm 26 is the first arm unit, the second arm 27 is the second arm unit, and the hand 29 is the hand unit. However, the second arm 27 may be the first arm unit, the third arm 28 may be the second arm unit, and the hand 29 may be the hand unit.

[0026] 2, the control device 40 is composed of an operation program storage unit 41, a movement position storage unit 42, an operation posture storage unit 43, a map information storage unit 44, a reference image storage unit 45, a manual driving control unit 46, an automatic driving control unit 47, a map information generation unit 48, a position recognition unit 49, a correction amount calculation unit 50, and an input / output interface 51. The control device 40 of this embodiment is connected to the robot 25, the camera 31, the automatic guided vehicle 35, and the operation panel 37 via this input / output interface 51, and the manual driving control unit 46 and the automatic driving control unit 47 control the position and opening / closing operations of the hand 29, the operation of the camera 31, and the operation of the automatic guided vehicle 35.

[0027] The control device 40 is configured by a computer including a CPU, RAM, ROM, etc. The manual driving control unit 46, the automatic driving control unit 47, the map information generation unit 48, the position recognition unit 49, the correction amount calculation unit 50, and the input / output interface 51 are functional modules whose functions are realized by computer programs and execute the processes described below. The operation program storage unit 41, the movement position storage unit 42, the operation posture storage unit 43, the map information storage unit 44, and the reference image storage unit 45 are configured by appropriate storage media such as RAM. In this example, the control device 40 is attached to the automatic guided vehicle 35 and is connected to the robot 25, the camera 31, the automatic guided vehicle 35, and the operation panel 37 by wire or wirelessly. However, this is not limited to this embodiment, and the control device 40 may be installed in an appropriate location other than the automatic guided vehicle 35. For example, the control device 40 may be installed in an operation panel. In this case, the control device 40 is connected to each unit by appropriate communication means.

[0028] The operation program storage unit 41 is a functional unit that stores an automatic driving program for automatically driving the automatic guided vehicle 35 and the robot 25 during production, and a map generation program for operating the automatic guided vehicle 35 when generating map information within the factory, which will be described later. The automatic driving program and the map generation program are input, for example, from an input / output unit provided on the operation panel 37, and stored in the operation program storage unit 41.

[0029] The automatic driving program includes command codes relating to the target position to which the automated guided vehicle 35 is to move, the speed of movement, and the direction of the automated guided vehicle 35, as well as command codes relating to the sequential operations of the robot 25 and command codes relating to the operation of the camera 31. The map generation program also includes command codes for causing the automated guided vehicle 35 to travel tracklessly throughout the factory, so that the map information generation unit 48 can generate map information.

[0030] The map information storage unit 44 is a functional unit that stores map information including the location information of machines, devices, equipment, etc. (devices, etc.) that are placed within the factory where the automated guided vehicle 35 travels, and this map information is generated by the map information generation unit 48.

[0031] When the map information generation unit 48 drives the automated guided vehicle 35 in accordance with the map generation program stored in the operation program storage unit 41 under the control of the automatic driving control unit 47 of the control device 40, which will be described in detail later, the map information generation unit 48 acquires spatial information within the factory from distance data detected by sensors and recognizes the planar shapes of devices and the like installed within the factory, and recognizes, for example, specific devices installed within the factory, such as the positions of the first machine tool 10A, the second machine tool 10B, the third machine tool 10C, the material stocker 20, and the product stocker 21, as well as their planar shapes (arrangement information), based on the planar shapes of pre-registered devices and the like. The map information generation unit 48 then stores the obtained spatial information and arrangement information of devices and the like in the map information storage unit 44 as map information within the factory.

[0032] The movement position memory unit 42 is a functional unit that stores movement positions as specific target positions to which the automated guided vehicle 35 moves, which correspond to command codes in the operation program. These movement positions include the work positions set for the first machine tool 10A, the second machine tool 10B, the third machine tool 10C, the material stocker 20, and the product stocker 21. The work positions in this embodiment are the moving parts of the robot-mounted moving device, i.e., the first and second equipment positions of the automated guided vehicle 35. Note that the target movement position, which is one of the movement positions in this embodiment, is set by, for example, manually driving the automated guided vehicle 35 using the operation panel 37 under the control of the manual operation control unit 46 to move it to each target position, and then storing the position data recognized by the position recognition unit 49 in the movement position memory unit 42. This operation is called a teaching operation.

[0033] The movement posture storage unit 43 is a functional module that stores data relating to movement postures (movement postures) of the robot 25 that change sequentially as the robot 25 operates in a predetermined order, corresponding to command codes in the operation program. The data relating to this movement posture is stored in the movement posture storage unit 43 when the robot 25 is manually operated to take each target posture by teaching using the operation panel 37 under the control of the manual operation control unit 46. In this embodiment, the rotation angle data of each joint (motor) of the robot 25 in each posture is stored in the movement posture storage unit 43 as data relating to the movement posture.

[0034] However, this is not limiting. For example, an image of the identification graphic may be captured by a camera in each posture, and a table that associates the identification position (e.g., biaxial coordinates) of the identification graphic in the captured image data with the robot posture may be stored in the movement posture storage unit 43. In this case, a table that also associates the identification position with the device position must be created. For example, the first device position and the first identification position are associated with a robot posture in which the angle between the first arm unit and the second arm unit is widened to 60°, and the first device position and the second identification position (a position different from the first identification position) are associated with a robot posture in which the arm is folded and the angle between the first arm unit and the second arm unit is 10°. Furthermore, instead of a table, a configuration may be provided in which a calculation unit is provided that performs calculations using a transformation matrix that can perform transformations that match the above-mentioned associations. In other words, a configuration in which the position of the robot's hand (two-dimensional coordinates, three-dimensional coordinates, etc.) is calculated based on the coordinates of the identification graphic.

[0035] Specific operating postures of the robot 25 in this embodiment are set for each of the material stocker 20, the first machine tool 10A, the second machine tool 10B, the third machine tool 10C, and the product stocker 21. For example, for the material stocker 20, the work start posture (take-out start posture) when work is started in the material stocker 20, each working posture (each taking-out posture) for gripping the unmachined workpiece W stored in the material stocker 20 with the hand 29 and taking it out of the material stocker 20, and the posture when taking-out is completed (take-out completion posture, which is the same posture as the take-out start posture in this example) are set as take-out operation postures (target working postures).

[0036] In addition, in the machine tool 10, the posture during the work removal operation in which the machined workpiece W2 is removed from the machine tool 10 (work removal operation posture) and the posture during the work attachment operation in which the unmachined workpiece W1 is attached to the machine tool 10 (work attachment operation posture) are set as target working postures.

[0037] The workpiece removal operation postures include, for example, the following postures. First, there is a work start posture before entering the machine tool 10. Next, there is a posture (imaging posture) (see FIG. 4) in which the hand 29 enters the machining area of ​​the machine tool 10 and an image of an identification graphic arranged in the machine tool is captured by the camera 31. Next, there is a posture (removal preparation posture) in which the hand 29 faces the machined workpiece W2 held in the chuck 12 of the machine tool 10. Thereafter, there is a posture (grasping posture) in which the hand 29 moves toward the chuck 12 and grips the machined workpiece W2 held in the chuck 12 with the hand 29. Next, there is a posture (removal posture) in which the hand 29 is separated from the chuck 12 and the machined workpiece W2 is removed from the chuck 12. Finally, there is a posture (work completion posture) in which the hand 29 and the camera 31 exit the machine tool 10. Each of these postures is set as a target work posture in this embodiment. In this embodiment, when the camera 31 is placed opposite the identification symbol, the camera 31 is preferably oriented such that the optical axis of the camera is perpendicular to the plane including the identification symbol. Furthermore, although the imaging posture in this embodiment is such that the hand 29 and the camera 31 enter the machine tool, this is not limiting. For example, as shown in FIG. 1, the hand 29 and the camera 31 may be located outside the machine tool 10. In this case, the position of the camera 31 of the robot 25 may be adjusted by rotation or movement so that the camera 31 can capture an image of the identification figure arranged in the machine tool 10, in other words, so that the camera 31 faces the identification figure, or in other words, so that the optical axis intersects (preferably orthogonal to) the plane including the identification figure. Furthermore, the imaging posture may be a posture in which the camera 31 is turned from the work start posture of this embodiment so that the camera 31 faces the identification figure.

[0038] The workpiece mounting operation posture may include, for example, the following postures. First, there is a work start posture before entering the machine tool 10. Next, there is a posture (imaging posture) (see FIG. 4 ) in which the hand 29 and camera 31 enter the machining area of ​​the machine tool 10, the camera 31 faces an identification figure provided on the support bar 15, and the camera 31 captures an image of the identification figure. Next, there is a posture (mounting preparation posture) in which the unmachined workpiece W1 held by the hand 29 faces the chuck 12 of the machine tool. Thereafter, there is a posture (mounting posture) in which the hand 29 is moved toward the chuck 12 so that the unmachined workpiece W1 can be held by the chuck 12. Next, there is a posture (detaching posture) in which the hand 29 is separated from the chuck 12. Finally, there is a posture (work completion posture) in which the hand 29 and camera 31 leave the machine tool 10. Each of these postures is set as a target work posture in this embodiment. Furthermore, although the imaging posture in this embodiment is a posture in which the hand 29 and the camera 31 are inserted into the machine tool 10, the present invention is not limited to this posture. For example, as shown in FIG. 1, the hand 29 and the camera 31 may be outside the machine tool 10 and image an identification symbol provided on a display board 16 inside the machine. In this case, the position of the camera 31 of the robot 25 may be adjusted by rotation or movement so that the camera 31 can image the identification symbol arranged inside the machine tool 10, in other words, so that the camera 31 faces the identification symbol, or in other words, so that the optical axis intersects (preferably orthogonal to) a plane including the identification symbol. Furthermore, the imaging posture may be a posture in which the camera 31 is turned from the work start posture of this embodiment so that the camera 31 faces the identification symbol.

[0039] The postures of the robot 25 relative to the product stocker 21 include a work start posture (storage start posture) when starting work in the product stocker 21, various work postures (storage postures) for storing the machined workpiece W2 held by the hand 29 in the product stocker 21, and a posture when storage is completed (storage completion posture, which is the same posture as the storage start posture in this example). In this embodiment, these postures are set as storage operation postures (target work postures).

[0040] The position recognition unit 49 is a functional module that executes a process of recognizing the position of the automated guided vehicle 35 within the factory based on distance data detected by the sensors and map information within the factory stored in the map information storage unit 44, and a process of recognizing the positions of the hand 29 and camera 31 serving as end effectors in three-dimensional space based on the rotation angles of the motors provided at each joint of the robot 25. The operation of the automated guided vehicle 35 is controlled by the automatic driving control unit 47 based on the position of the automated guided vehicle 35 recognized by the position recognition unit 49. The position of the automated guided vehicle 35 on the X-Y plane recognized by the position recognition unit 49, as well as the positions of the hand 29 and camera 31 in three-dimensional space (three-dimensional space defined by the X-, Y-, and Z-axes), are displayed on the display of the operation panel 37. The positions of the hand 29 and camera 31 in three-dimensional space can be calculated using a predetermined conversion formula based on the length of each arm of the robot 25 and the rotation angles of the motors provided at each joint.

[0041] The manual driving control unit 46 is a functional module that operates the automatic guided vehicle 35, the robot 25, and the camera 31 in accordance with operation signals input by an operator via an operation panel 37. That is, under the control of the manual driving control unit 46, the operator can use the operation panel 37 to translate the automatic guided vehicle 35 along the X-axis and Y-axis and capture images with the camera 31 while checking the position of the automatic guided vehicle 35 recognized by the position recognition unit 49 and displayed on the display, as well as the positions of the hand 29 and the camera 31 in three-dimensional space. Furthermore, the operator can translate the hand 29 and the camera 31 of the robot 25 along the X-axis, Y-axis, and Z-axis, and rotate them around the X-axis, Y-axis, and Z-axis, respectively. Note that the rotations around the X-axis, Y-axis, and Z-axis are represented by rx, ry, and rz, respectively.

[0042] The automatic driving control unit 47 is a functional module that uses either the automatic driving program or the map generation program stored in the operation program storage unit 41, and operates the automatic guided vehicle 35, the robot 25, and the camera 31 in accordance with the program. At that time, the data stored in the movement position storage unit 42 and the operation posture storage unit 43 are used as necessary.

[0043] The reference image storage unit 45 is a functional module that stores, as a reference image, an image obtained by capturing an image of an identification figure (FIG. 4) provided on the support bar 15 of the tool presetter 13 with the camera 31 when the automated guided vehicle 35 is at a work position set with respect to the machine tool 10 and the robot 25 is in an imaging attitude during a teaching operation. Note that the identification figure is not limited to the one provided on the tool presetter as shown in FIG. 4. As shown in FIG. 15, an identification figure of a detachable tool with an identification figure that can be attached to the tool spindle may also be used.

[0044] For example, in the case of a horizontal lathe 100 equipped with a tool spindle 105 for rotating a tool, as shown in FIG. 15, the display panel 16 can be supported horizontally by a holder 106, and the holder 106 can be attached to the tool spindle 105. In this case, when machining is performed by the lathe 100, the holder 106 is stored in a tool magazine, which is a tool storage section, and when work is performed by the robot 25, the holder 106 is removed from the tool magazine and attached to the tool spindle 105. In FIG. 15, reference numeral 101 denotes a first spindle, reference numeral 103 denotes a second spindle, and these are arranged coaxially and facing each other. Reference numeral 102 denotes a first chuck attached to the first spindle 101, and reference numeral 104 denotes a second chuck attached to the second spindle 103. Further, reference numeral 107 denotes a tool rest, reference numeral 108 denotes a turret provided on the tool rest 107, and reference numeral 109 denotes a support jig for supporting the workpiece W, which is attached to the outer surface of the turret 108.

[0045] When the robot 25 is automatically operated under the control of the automatic operation control unit 47 in accordance with the automatic operation program stored in the operation program memory unit 41 to perform the workpiece removal operation and the workpiece attachment operation, the robot 25 is in the image capturing posture and the identification figure is captured by the camera 31. Based on the current image of the identification figure obtained during automatic operation and the reference image (image captured during the teaching operation) stored in the reference image memory unit 45, the correction amount calculation unit 50 estimates the position error amounts of the camera 31 between the current posture (actual operation posture) of the robot 25 and the posture during the teaching operation (target operation posture), including the position error amounts (Δx, Δy) of the camera 31 in two mutually orthogonal axis directions (X-axis and Y-axis directions in this example) set in a plane parallel to the identification figure, and the rotation error amount (Δrz) of the camera 31 around a vertical axis (Z-axis in this example) orthogonal to the plane, and calculates the correction amount for the operating part (corresponding to the hand 29 or the camera 31) in the actual operation posture based on each estimated error amount (see FIG. 12). Note that this position error (Δx, Δy) and rotation error (Δrz) are due to a positioning error relative to the target work position of the automated guided vehicle 35 set during the teaching operation, and essentially correspond to the positioning error of the automated guided vehicle 35 relative to this target work position and the position at which the automated guided vehicle 35 actually stops.

[0046] The correction amount calculated by the correction amount calculation unit 50 is used to correct the take-out preparation posture, gripping posture, and removal posture in the workpiece take-out operation posture, and the attachment preparation posture, attachment posture, and separation posture in the workpiece attachment operation posture when the robot 25 works on the machine tool 10, and the position (target position) of the hand 29 in each posture is corrected by the automatic operation control unit 47 based on the correction amount. Note that the correction amount is converted into angle data of each joint of the robot 25 by the automatic operation control unit 48 using a preset conversion formula, and the robot 25 is controlled in accordance with the converted angle data.

[0047] According to the system 1 of this example having the above configuration, the automatic operation control unit 47 of the control device 40 executes the automatic operation program stored in the operation program memory unit 41 to control the automatic guided vehicle 35 and the robot 25, and causes the machine tool 10, material stocker 20, and product stocker 21 to perform the operations shown in Figure 6.

[0048] That is, automatic operation control unit 47 first waits until it receives a signal indicating that machining is complete from machine tool 10 (step S1). When machining is completed in machine tool 10, machine tool 10 opens its door cover to allow robot 25 to enter the machining area, and advances support bar 15 of tool presetter 13 into the machining area, and then transmits a machining completion signal to machine tool 10.

[0049] 7 and 8, the automatic operation control unit 47 executes the removal operation of the machined workpiece W2 (step S2). That is, the automatic operation control unit 47 causes the robot 25 to assume a work start posture (step S201), and then positions the automatic guided vehicle 35 at a work position set with respect to the machine tool 10 (step S202).

[0050] Next, the automatic operation control unit 47 moves the robot 25 to an imaging posture (step S203), and the camera 31 captures an image of the identification graphic attached to the support bar 15 (step S204). When the identification graphic is captured by the camera 31 in this manner, the correction amount calculation unit 50 estimates the positional error amounts Δx, Δy and rotational error amount Δrz between the imaging posture at the time of the teaching operation of the robot 25 and the current imaging posture, based on the image including the identification graphic and the reference image including the identification image stored in the reference image storage unit 45, and calculates correction amounts in the X-axis, Y-axis and rz directions for the posture of the robot 25 for a subsequent workpiece removal operation, based on the estimated error amounts.

[0051] The automatic operation control unit 47 then acquires the calculated correction amounts from the correction amount calculation unit 50 (step S205), and then shifts the robot 25 to a take-out preparation posture corrected based on the acquired correction amounts for the X-axis, Y-axis, and rz directions (step S206), and monitors whether this operation has been completed (step S207). When correcting the working posture of the robot 25, if the positioning error amount of the automatic guided vehicle 35 to the working position exceeds the movable range of the operating unit (in this case, the hand 29) limited by the singular point, the robot 25 cannot complete the operation and is stopped. Therefore, in this example, the automatic operation control unit 47 monitors whether the robot 25 can complete the operation (step S207), and if the operation can be completed, shifts the robot 25 to a gripping posture, which is the next operation (step S214). If the operation cannot be completed within the scheduled time, the automatic operation control unit 47 executes the recovery operation of steps S208 to S213.

[0052] In the recovery operation, the automatic driving control unit 47 first shifts the robot 25 to the posture immediately before the stopped state, i.e., the imaging posture (step S208), and then moves the automatic guided vehicle 35 in the opposite direction to the positional deviation in the X-axis and Y-axis directions by the position error amounts Δx and Δy, respectively, to adjust its working position (step S209).

[0053] For example, in FIG. 1 , the automated guided vehicle 35 (robot-mounted transport device) moves at a first speed SP1 and stops in front of the second machine tool 10B. After stopping, an image of the identification graphic is captured in the imaging posture. Correction operation is performed based on the captured image. If a recovery operation is determined to be necessary, the automated guided vehicle 35 is moved by the calculated position error amount Δx at a second speed SP2 slower than the first speed SP1. The example in FIG. 1 illustrates a case where the position error amount Δy = 0. By moving by the position error amount Δx, the automated guided vehicle 35 moves to the same position as the teaching position. This eliminates the positional deviation of the actual operating position of the automated guided vehicle 35 from the target work position set during the teaching operation, and the automated guided vehicle 35 is positioned approximately at the target work position. The movement speed of the automated guided vehicle 35 during position adjustment may be the same as the movement speed when positioning the automated guided vehicle 35 at the target work position during automatic operation. However, as described above, it is preferable that the movement speed be slower than this speed. In this way, it is possible to accurately adjust the position of the automatic guided vehicle 35, that is, with high precision, resulting in improved accuracy in the position of the robot.

[0054] Next, the automatic driving control unit 47 again captures an image of the identification pattern using the camera 31 (step S210), acquires the correction amount calculated based on the image of the identification pattern from the correction amount calculation unit 50 (step S211), moves the robot 25 to a pick-up preparation posture corrected based on the acquired new correction amounts in the X-axis, Y-axis, and rz directions (step S212), and monitors whether this operation is completed (step S213). If the operation is completed, the automatic driving control unit 47 executes the processing of step S214. On the other hand, if the operation is not completed, it is likely that the problem related to the singularity has been resolved by the above-mentioned recovery operation, but it is considered that the operation has not been completed due to other causes. Therefore, an alarm is output (step S220), and the series of operations ends (step S6).

[0055] In step S214, the automatic operation control unit 47 shifts the robot 25 to a gripping posture, and after this operation is completed (step S215), shifts the robot 25 to a removal posture (step S216). Then, after this operation is completed (step S217), the automatic operation control unit 47 next shifts the robot 25 to a work completion posture, and after this operation is completed (step S219), ends the series of workpiece removal operations. Note that while the robot 25 is shifting from the gripping posture to the removal posture, a chuck open command is sent from the automatic operation control unit 47 to the machine tool 10, and the chuck 12 is thereby opened.

[0056] On the other hand, if the transition to the grasping posture, the transition to the detachment posture, and the transition to the work completion posture are not completed within the specified time, an alarm is output (step S220) as described above, and the series of processes is terminated (step S6).

[0057] This completes the operation of removing the machined workpiece W2.

[0058] Next, the automatic operation control unit 47 executes a storing operation of the machined workpiece W2 (step S3). In this storing operation, the automatic operation control unit 47 moves the automatic guided vehicle 35 to a work position set for the product stocker 21, and causes the robot 25 to sequentially assume a storage start posture when starting work in the product stocker 21, various storage postures for storing the machined workpiece held by the hand 29 in the product stocker 21, and a storage completion posture when storage is completed, thereby storing the machined workpiece held by the hand 29 in the product stocker 21.

[0059] Next, the automatic operation control unit 47 executes a take-out operation of the unmachined workpiece W1, which is the material (step S4). In this take-out operation, the automatic operation control unit 47 moves the automated guided vehicle 35 to a work position set with respect to the material stocker 20, and causes the robot 25 to sequentially assume a take-out start posture when starting work at the material stocker 20, various take-out postures for gripping the unmachined workpiece W1 stored in the material stocker 20 with the hand 29 and taking it out of the material stocker 20, and a take-out completion posture when the take-out is completed, and causes the hand 29 to grip the unmachined workpiece W.

[0060] Next, the automatic operation control unit 47 executes the mounting operation of the unmachined workpiece W1 (step S5). This mounting operation is similar to the operation shown in FIGS. 7 and 8, and the removal preparation posture, gripping posture, and removal posture of the removal operation shown in FIGS. 7 and 8 can be read as the mounting preparation posture, mounting posture, and separation posture of the mounting operation, respectively. Although a detailed description of this mounting operation will be omitted, by this mounting operation, the unmachined workpiece W1 held by the hand 29 is transferred to the chuck 12 of the machine tool 10 and gripped by the chuck 12. Note that in this mounting operation, after the robot 25 has shifted to the mounting posture, a chuck close command is sent from the automatic operation control unit 47 to the machine tool 10, and in response to this, the machine tool 10 closes the chuck 12. As a result, the unmachined workpiece W1 is gripped by the chuck 12.

[0061] After completing this mounting operation, automatic operation control unit 47 transmits a machining start command to machine tool 10, causing machine tool 10 to perform the machining operation.

[0062] By repeating the above steps, unmanned automatic production is continuously performed in the system 1 of this example (step S6). In this embodiment, when the automated guided vehicle 35 moves to each work position, it moves at a third speed SP3 that is faster than the second speed SP2.

[0063] As described above, according to the system 1 of this embodiment, even if the robot 25 stops because the positioning error when positioning the automated guided vehicle 35 at a work position set with respect to the machine tool 10 exceeds the movable range of the hand 29 limited by the singular point of the robot 25, the robot 25 can be automatically restored from the stopped state and the working postures of the robot 25, i.e., the take-out preparation posture, the gripping posture, and the removal posture in the take-out operation, and the attachment preparation posture, the attachment posture, and the separation posture in the attachment operation (in other words, the position of the hand 29 in each posture), can be appropriately corrected. In other words, the accuracy of the robot position can be improved. This can avoid the troublesome work of manually restoring the system 1 or redoing the teaching operation when the robot 25 stops, thereby improving the availability of the system 1.

[0064] Furthermore, after the above-mentioned recovery operation, the positioning error amount is detected again at the target work position of the automatic guided vehicle 35, and based on the detected positioning error amount, the take-out preparation posture, gripping posture, and removal posture in the take-out operation of the robot 25, and the attachment preparation posture, attachment posture, and separation posture in the attachment operation are corrected, so that each posture can be controlled with high precision; in other words, the hand 29 of the robot 25 can be positioned accurately, that is, with high precision, at the target position.

[0065] Although one embodiment of the present invention has been described above, the specific aspects that the present invention can adopt are not limited to this. Furthermore, the present invention will not be described as a separate system from the systems described in the following embodiments, and some of the configurations of the respective embodiments may be combined for implementation.

[0066] For example, in the above example, after the recovery operation is performed, the amount of positioning error of the automated guided vehicle 35 with respect to the target work position is detected again (steps S210 to S211), but this is not limited to this. For example, there are cases where high accuracy of positioning is not required for the work posture of the robot 25 (positioning of the hand 29). In such cases, after the recovery operation is performed, the subsequent operation may be performed without detecting the amount of positioning error of the automated guided vehicle 35 with respect to the target work position again.

[0067] This example is shown in Fig. 9. The operation shown in Fig. 9 follows step S209 shown in Fig. 7, and after adjusting the working position of the automatic guided vehicle 35, the robot 25 is caused to take the take-out preparation posture (attachment preparation posture) (step S232), the gripping posture (attachment posture) (step S234), the removal posture (removal posture) (step S234), and the work completion posture (step S236) in that order, without making any corrections in the X-axis and Y-axis directions, while making corrections in the rotational direction (rz) using the correction amount calculated in step S205.

[0068] By adjusting the working position by moving the automatic guided vehicle 35 in the direction opposite to the positional deviation in the X-axis and Y-axis directions by the position error amounts Δx and Δy (step S209), the positional deviation of the automatic guided vehicle 35 in the X-axis and Y-axis directions from the target working position set during the teaching operation is almost eliminated, and the automatic guided vehicle 35 is almost positioned with respect to the target working position. Therefore, by correcting only the rotational direction (rz) without making any particular correction in the X-axis and Y-axis directions, the working posture of the robot 25 can be made to be the target working posture set by the teaching operation.

[0069] In the example shown in FIG. 9, if the transition to each working posture is not completed within a predetermined time, an alarm is output (step S238) and the series of processes is terminated (step S6) in the same manner as above.

[0070] <<Embodiment 2>> In the first embodiment, an example was described in which the identification figure was arranged parallel to a horizontal plane, but in the present embodiment, an example will be described in which the identification figure is arranged parallel to a plane intersecting the horizontal plane (particularly, a plane perpendicular to the horizontal plane). Fig. 14 is a diagram showing the difference in appearance of the identification image when captured by a camera 31 with an optical axis in the horizontal direction, where (a) shows the captured images of the identification figure on the first machine tool 10A and the second machine tool 10B, and (b) shows the captured image of the identification figure on the third machine tool 10C.

[0071] FIG. 14(a) shows an example in which, with the display board 16 positioned as shown in FIG. 1, an image of the identification pattern captured by the camera 31 when the automated guided vehicle 35 (robot-mounted mobile device) is stopped in front of the first machine tool 10A is the same as the image captured during teaching. It also shows an example in which an image captured when the automated guided vehicle 35 is stopped in front of the second machine tool 10B is different from the image captured during teaching. These examples show no deviation on the y-axis, but the coordinate positions along the x- and z-axes are different. Using FIG. 16, we will explain how the control unit determines whether to control the robot's hand to attach or detach a workpiece or move the robot-mounted mobile device to change the position of the mobile device when an image including an identification pattern is captured. As shown in FIG. 16(a), an image corresponding to the camera frame is displayed. In image processing, a portion of the image is set as a predetermined range, as shown in FIG. 16(a). The area inside the predetermined range on the image is set as the predetermined range, and the area outside the predetermined range is set as the outside of the predetermined range. Furthermore, image processing involves superimposing information related to the position of the identification figure on the image and information about the predetermined range. In this embodiment, the center position of the identification figure is used as information related to the position of the identification figure. The control unit detects the center position of the identification figure in the captured image and determines whether the detected position is within a predetermined range. If the control unit determines that the center position of the identification figure is within the predetermined range, it controls the robot's hand unit to transport the workpiece, etc. On the other hand, if the control unit determines that the center position of the identification figure is not within the predetermined range (outside the predetermined range), it moves the moving unit and corrects the position of the robot-mounted moving device. As shown in FIG. 16(b), if the center of the identification figure is outside a predetermined range within the camera frame, which is the range captured by the camera, the control unit moves the movement unit of the robot-mounted mobile device to change the device position. The camera then captures an image of the identification figure. If the center of the identification figure is within the predetermined range, the control unit controls the position of the robot hand unit of the robot-mounted mobile device to perform tasks such as attaching and detaching a workpiece. The predetermined range may be defined as a circle with a radius equal to one-quarter of the diagonal length of the camera frame. Alternatively, the entire camera frame may be defined as the predetermined range. For example, the control unit may be configured to control the position of the robot hand unit to attach and detach a workpiece as long as the center of the identification figure is captured within the camera frame. In this way, the predetermined range can be set appropriately taking into account the movable range of the robot arm. 14(b) shows an example of a hypothetical camera frame when an identification graphic is captured by camera 31 while automatic guided vehicle 35 is stopped in front of third machine tool 10C. In this example, as shown in FIG. 1, door 18 of third machine tool 10C is closed, and an identification image inside third machine tool 10C cannot be captured (see FIGS. 1 and 14). In this case, control device 40 of the robot-mounted transfer device preferably sends an instruction to third machine tool 10C to open door 18, or performs processing to notify a worker or supervisor that door 18 of third machine tool 10C is not open.

[0072] Furthermore, the automated guided vehicle 35 of the robot-mounted mobile device of this embodiment can adopt a mode of moving at a speed SP16 > speed SP14 > speed SP13 > speed SP15 > speed SP12 > speed SP11, as shown in FIG. 13. While not limited to this speed, it is preferable to slow down the speed SP11 at which the automated guided vehicle 35 moves to the stop position of the image capture posture to increase the accuracy of the stop position. For example, the following relationship may be possible: speed SP14 > speed SP16 > speed SP15 > speed SP13 > speed SP11 > speed SP12. Note that in FIG. 13, the arrows indicate the movement path of the automated guided vehicle 35.

[0073] Furthermore, as shown in Fig. 13, the movable range of hand 29 of robot 25 will be within the dashed circle of MO1 if there are no obstacles. However, as shown in Fig. 13, machine tool 10 is present within the movable range of hand 29 of robot 25, and therefore hand 29 cannot grasp workpieces or the like placed in area MO3 marked with a crescent moon or area MO4 marked with a star. In the example shown in Fig. 13, the hand of the robot can place and remove objects such as workpieces in area MO2.

[0074] To reiterate, the above-described embodiments are illustrative in all respects and are not limiting. Variations and modifications are possible for those skilled in the art. The scope of the present invention is defined by the claims, not the above-described embodiments. Furthermore, the scope of the present invention includes modifications from the embodiments within the scope of the claims and their equivalents. [Explanation of symbols]

[0075] 1 System 10 Machine tools 11 Spindle 12 Zipper 13 Tool Presetter 14 Contacts 15 Support bar 16 Display board 20 Material Stocker 21 Product Stocker 25 Robot 29 hands 31 Camera 35 Automated Guided Vehicle 37 Control panel 40 Control device 41 Operation program storage unit 42 Movement position memory section 43 Motion posture memory section 44 Map information storage unit 45 Reference image storage unit 46 Manual operation control unit 47 Automatic driving control unit 48 Map information generation unit 49 Position recognition part 50 Correction amount calculation section 51 Input / Output Interface W1 Work before machining W2 Machined workpiece

Claims

1. A robot-mounted mobile device equipped with a robot that performs an operation of grasping an object based on information about an identification graphic arranged on a plane intersecting with a horizontal plane of a machine tool, a robot having (i) a hand unit for grasping the object, (ii) a second arm unit movably connecting the hand unit, (iii) a first arm unit movably connecting the second arm unit, and (iv) a camera provided on the hand unit side opposite to the first arm unit; a moving unit on which the robot is mounted and which can move; a control unit that causes a hand unit of the robot to perform an operation of grasping an object inside the machine tool when the robot-mounted transfer device is at a predetermined position in front of a door that opens and closes a machining area of ​​the machine tool, The control unit (a) at the predetermined position, changes the robot's posture to an imaging posture in which the camera faces an identification figure arranged on a plane intersecting the horizontal plane of the machine tool, (b) in the imaging posture, causes the camera to image the identification figure, and (c) adjusts the position of the robot's hand unit based on information about the imaged identification figure, and causes the robot to perform an operation to grasp an object within the machine tool.

2. 2. A robot-mounted transfer device according to claim 1, wherein said identification graphic is arranged on a plane perpendicular to a horizontal plane of said machine tool.

Images