ROBOT, ROBOT SYSTEM, AND METHOD FOR SETTING COORDINATE SYSTEM OF ROBOT
This application is based on and claims priority to Japanese Patent Application No. 2017-207772, filed on Oct. 27, 2017, the entire content of which is incorporated herein by reference. The present invention relates to a robot, a robot system, and a method for setting a coordinate system of a robot. The coordinate system of a robot is set in a robot or a control apparatus for the robot at the time of manufacturing or shipping the robot, and the robot is controlled by the control apparatus using the coordinate system as a reference. When a camera is attached to the robot, and the robot is operated based on an image captured by the camera, the coordinate system of the image captured by the visual sensor is converted into the coordinate system of the robot, thus achieving a task performed by the robot with respect to a workpiece or the like in the image (see Japanese Unexamined Patent Application, Publication No. H2-12504, for example). According to a first aspect of the present invention, there is provided a robot installed on a reference flat surface, the robot including a robot control unit configured to control an operation of the robot, wherein the robot control unit is configured to set a coordinate system of the robot, installed on the reference flat surface, using measurement results of at least position coordinates in a vertical direction of three or more measurement points on the reference flat surface and measurement results of position coordinates of a plurality of reference reflection portions provided on a base portion of the robot. According to a second aspect of the present invention, there is provided a robot system including: a robot installed on a reference flat surface; and a robot control unit configured to control an operation of the robot, wherein the robot control unit is configured to set a coordinate system of the robot, installed on the reference flat surface, using measurement results of at least position coordinates in a vertical direction of three or more measurement points on the reference flat surface and measurement results of position coordinates of a plurality of reference reflection portions provided on a base portion of the robot, and the robot system further comprises an operation program re-setting means configured to perform re-setting of a parameter of an operation program based on displacement of the set coordinate system, the displacement is displacement of the set coordinate system with respect to an initial coordinate system set in advance in the robot or the robot control unit, or displacement of a z axis of the set coordinate system with respect to a vertical axis, the operation program is for operating the robot. According to a third aspect of the present invention, there is provided a method for setting a coordinate system of a robot, the method including: a step of installing a robot on a reference flat surface; a flat-surface-position measuring step of measuring at least position coordinates in a vertical direction of three or more measurement points on the reference flat surface; a reflection-portion-position measuring step of measuring position coordinates of a plurality of reference reflection portions provided on a base portion of the robot; and a coordinate system setting step of setting a coordinate system of the robot, installed on the reference flat surface, using the position coordinates of the measurement points on the reference flat surface and the position coordinates of the reference reflection portions. A robot system according to an embodiment of the present invention is described hereinafter with reference to drawings. As shown in As shown in A processing tool 12 is mounted at a distal end portion of the robot 2, and the processing tool 12 performs spot welding on the workpiece W. When the robot 2 is provided for conveying a workpiece, a chuck a suction device or the like, each of which forms a holding device for holding the workpiece, is mounted at the distal end portion of the robot 2 in place of the processing tool 12. As shown in In this embodiment, the reference flat surface 5 As shown in The memory device 23 stores a system program 23 The robot controller 21 operates by the system program 23 The position measuring apparatus 4 includes a measurement control apparatus 50 shown in As shown in The vertical axis motor 42 is provided to rotate the laser head 41 and the horizontal axis motor 43 about a vertical axis, and the horizontal axis motor 43 is provided to rotate the laser head 41 about a horizontal axis. The vertical axis motor 42 and the horizontal axis motor 43 are connected to the measurement control apparatus 50, and the vertical axis motor 42 and the horizontal axis motor 43 are controlled by the measurement control apparatus 50. Further, each motor 42, 43 has an operation position detection device, such as an encoder, which detects an operation position of the motor 42, 43, and detected values of the operation position detection devices are transmitted to the measurement control apparatus 50. A laser beam emitting section 41 As shown in The memory device 53 stores a system program 53 In this embodiment, based on at least the vertical position of the position coordinates of the plurality of points on the upper surface of the reference flat surface 5 A coordinate system (initial coordinate system) is set in the robot 2 or the robot control unit 20 of this embodiment before the robot 2 is installed on the reference flat surface 5 The operation of the robot controller 21 and the controller 51 when performing re-setting of the coordinate system of the robot 2 is described below. First, the position measuring apparatus 4 is positioned at an approximate position for measurement. For example, when the controller 51 receives a predetermined signal (in association with a first step), the controller 51 is operated by the position measurement program 53 In this embodiment, adjusting the direction of the laser head 41 by the controller 51 using the vertical axis motor 42 and the horizontal axis motor 43 may allow laser beam to irradiate the respective reflection members 2 Subsequently, the controller 51 directs laser beam to irradiate respective three or more measurement points (four measurement points in this embodiment) on the reference flat surface 5 In this embodiment, adjusting the direction of the laser head 41 by the controller 51 using the vertical axis motor 42 and the horizontal axis motor 43 may allow laser beam to irradiate the respective measurement points from the laser head 41. Alternatively, manually adjusting the direction of the laser head 41 by an operator may allow laser beam to irradiate the respective measurement points from the laser head 41. Further, reflection members may be provided in the respective measurement points on the reference flat surface 5 Subsequently, based on the measured position coordinates of the respective reflection members 2 For example, the controller 51 sets the x axis of the coordinate system of the robot 2 and the y axis, orthogonal to the x axis, on a flat surface which contains the position coordinates of all measurement points, and the controller 51 sets the z axis of the coordinate system of the robot 2 in the direction perpendicular to the flat surface. The x axis is set so as to be parallel to a straight line which passes through the respective reflection members 2 Subsequently, the controller 51 transmits, to the robot control unit 20, the measured position coordinates of the respective measurement points and the respective reflection members 2 The robot controller 21 is operated based on the coordinate system setting program 23 For example, the robot controller 21 sets the x′ axis of the coordinate system of the robot 2 and the y′ axis, orthogonal to the x′ axis, on a flat surface which contains the position coordinates of all measurement points, and the robot controller 21 sets the z′ axis of the coordinate system of the robot 2 in the direction perpendicular to the flat surface. The x′ axis is set so as to be parallel to a straight line which passes through the respective reflection members 2 A predetermined position with respect to the reflection members 2 Subsequently, the robot controller 21 acquires displacement of the coordinate system, for which the re-setting is performed, with respect to the initial coordinate system, or acquires displacement of the z′ axis of the coordinate system, for which the re-setting is performed, with respect to the vertical axis (in association with a seventh step). For example, the robot controller 21 acquires gradients of the x′ axis, the y′ axis, and the z′ axis of the coordinate system, for which the re-setting is performed, with respect to the x axis, the y axis, and the z axis of the initial coordinate system. The robot controller 21 acquires a difference between the coordinates of the origin, for which the re-setting is performed, and the coordinates of the origin of the initial coordinate system, and a gradient and a direction of the z′ axis of the coordinate system, for which the re-setting is performed, with respect to the vertical axis. The robot controller 21 is operated based on the operation program re-setting program 23 The operation program re-setting program 23 According to this embodiment, the robot 2 is installed on the reference flat surface 5 For example, in performing correction of position displacement (calibration) of the distal end of the robot 2 which may occur due to gravity, assembly errors or the like, the coordinate system of the robot 2 forming a reference for the correction is accurately set with respect to the reference flat surface 5 Further, in the off-line program making device, such as the simulation device 3, the z axis of the coordinate system of the robot 2 is completely parallel to the vertical axis. However, it is extremely difficult to make the z axis of the initial coordinate system of the actually installed robot 2 completely parallel to the vertical axis. On the other hand, in this embodiment, the coordinate system of the robot 2 installed on the reference flat surface 5 The coordinate system, which is set, is set in the off-line program making device, such as the simulation device 3, thus allowing the off-line program making device to generate the operation program 23 Further, when operation ranges of two robots 2 overlap each other, coordinate systems of the two robots respectively installed on the reference flat surfaces 5 Further, in this embodiment, re-setting of parameters of the operation program 23 The reference flat surface 5 In this embodiment, the position coordinates of the plurality of measurement points on the reference flat surface 5 The following aspects of the present invention are derived from the aforementioned disclosure. According to a first aspect of the present invention, there is provided a robot installed on a reference flat surface, the robot including a robot control unit configured to control an operation of the robot, wherein the robot control unit is configured to set a coordinate system of the robot, installed on the reference flat surface, using measurement results of at least position coordinates in a vertical direction of three or more measurement points on the reference flat surface and measurement results of position coordinates of a plurality of reference reflection portions provided on a base portion of the robot. In the first aspect, the robot is installed on the reference flat surface, and setting of the coordinate system of the robot installed on the reference flat surface is performed using the measurement results of at least the position coordinates in the vertical direction of the three or more measurement points on the reference flat surface and the measurement results of the position coordinates of the plurality of reference reflection portions provided on the base portion of the robot. Accordingly, compared to a case where the initial coordinate system, which is set in advance in the robot or the robot control unit at the time of manufacturing the robot, is used as it is, it is possible to more accurately control the operation of the installed robot. For example, in performing correction of position displacement (calibration) of the distal end of the robot which may occur due to gravity, assembly errors or the like, the coordinate system of the robot forming a reference for the correction is accurately set with respect to the reference flat surface. Accordingly, such a configuration is advantageous for accurately performing the calibration. Further, in an off-line program making device, such as a simulation device, the z axis of the coordinate system of the robot is completely parallel to the vertical axis. However, it is extremely difficult to make the z axis of the initial coordinate system of the actually installed robot completely parallel to the vertical axis. On the other hand, in this embodiment, the coordinate system of the robot installed on the reference flat surface is set with respect to the reference flat surface, thus enabling the adjustment for making the coordinate system approach an ideal state, and enabling setting operation which utilizes the coordinate system. Accordingly, such a configuration is advantageous for preventing interference or the like between a workpiece and the robot in operating the robot by the operation program generated by the off-line program making device. The coordinate system, which is set, is set in the off-line program making device, such as the simulation device, thus allowing the off-line program making device to generate an operation program which closer matches actual conditions. Further, when operation ranges of the plurality of robots overlap each other, coordinate systems of the plurality of robots respectively installed on the reference flat surfaces are accurately set with respect to the respective reference flat surfaces. Accordingly, such a configuration is advantageous for operating the plurality of robots while avoiding interference with each other. In the above-mentioned aspect, it is preferable that the robot control unit is configured to receive the position coordinates on the reference flat surface and the position coordinates of the reference reflection portions from a position measuring apparatus which uses a laser beam, and is configured to set the coordinate system using the received position coordinates. In such a configuration, the position measuring apparatus which uses a laser beam is used so that setting of the coordinate system can be easily performed with a short time. In the above-mentioned aspect, it is preferable that the reference flat surface be a flat surface which has a guaranteed flatness. The flatness of the reference flat surface is guaranteed in this manner. That is, the reference flat surface has a known flatness of a predetermined value or less. Accordingly, it is possible to set the coordinate system of the robot with more certainty. According to a second aspect of the present invention, there is provided a robot system including: a robot installed on a reference flat surface; and a robot control unit configured to control an operation of the robot, wherein the robot control unit is configured to set a coordinate system of the robot, installed on the reference flat surface, using measurement results of at least position coordinates in a vertical direction of three or more measurement points on the reference flat surface and measurement results of position coordinates of a plurality of reference reflection portions provided on a base portion of the robot, and the robot system further comprises an operation program re-setting means configured to perform re-setting of a parameter of an operation program based on displacement of the set coordinate system, the displacement is displacement of the set coordinate system with respect to an initial coordinate system set in advance in the robot or the robot control unit, or displacement of a z axis of the set coordinate system with respect to a vertical axis, the operation program is for operating the robot. Also in the second aspect, the robot is installed on the reference flat surface, and setting of the coordinate system of the robot installed on the reference flat surface is performed using the measurement results of at least the position coordinates in the vertical direction of the three or more measurement points on the reference flat surface, and the measurement results of the position coordinates of the plurality of reference reflection portions provided on the base portion of the robot. Accordingly, compared to a case where the initial coordinate system, which is set in advance in the robot or the robot control unit at the time of manufacturing the robot, is used as it is, it is possible to more accurately control the operation of the installed robot. Further, re-setting of parameters of the operation program for operating the robot is performed based on displacement of the coordinate system, which is set, with respect to the initial coordinate system set in advance in the robot or the robot control unit, or based on displacement of the z axis of the coordinate system, which is set, with respect to the vertical axis. Such a configuration is advantageous for more accurately controlling the operation of the robot by the operation program. According to a third aspect of the present invention, there is provided a method for setting a coordinate system of a robot, the method including: a step of installing a robot on a reference flat surface; a flat-surface-position measuring step of measuring at least position coordinates in a vertical direction of three or more measurement points on the reference flat surface; a reflection-portion-position measuring step of measuring position coordinates of a plurality of reference reflection portions provided on a base portion of the robot; and a coordinate system setting step of setting a coordinate system of the robot, installed on the reference flat surface, using the position coordinates of the measurement points on the reference flat surface and the position coordinates of the reference reflection portions. In the coordinate system setting step in the third aspect, it is preferable that a robot control unit receives the position coordinates on the reference flat surface and the position coordinates of the reference reflection portions from a position measuring apparatus which uses a laser beam, and the robot control unit sets the coordinate system using the received position coordinates. In the third aspect, it is preferable that the method further include an operation program re-setting step of performing re-setting of a parameter of an operation program based on displacement of the set coordinate system, the displacement is displacement of the set coordinate system with respect to an initial coordinate system set in advance in the robot or the robot control unit, or displacement of a x axis of the set coordinate system with respect to a vertical axis, the operation program is for operating the robot. According to the aforementioned aspects, it is possible to more accurately control the operation of the installed robot. A robot includes a robot control unit configured to control an operation of a robot, wherein the robot control unit is configured to set a coordinate system of the robot installed on a reference flat surface using measurement results of at least position coordinates in a vertical direction of three or more measurement points on the reference flat surface on which the robot is installed and measurement results of position coordinates of a plurality of reference reflection portions provided on a base portion of the robot. 1. A robot installed on a reference flat surface, the robot comprising a robot control unit configured to control an operation of the robot,
wherein the robot control unit is configured to set a coordinate system of the robot, installed on the reference flat surface, using measurement results of at least position coordinates in a vertical direction of three or more measurement points on the reference flat surface and measurement results of position coordinates of a plurality of reference reflection portions provided on a base portion of the robot. 2. The robot according to 3. The robot according to 4. A robot system comprising:
a robot installed on a reference flat surface; and a robot control unit configured to control an operation of the robot, wherein the robot control unit is configured to set a coordinate system of the robot, installed on the reference flat surface, using measurement results of at least position coordinates in a vertical direction of three or more measurement points on the reference flat surface and measurement results of position coordinates of a plurality of reference reflection portions provided on a base portion of the robot, and the robot control unit or another control unit is configured to conduct an operation program re-setting process to perform re-setting of a parameter of an operation program based on displacement of the set coordinate system, the displacement is displacement of the set coordinate system with respect to an initial coordinate system set in advance in the robot or the robot control unit, or displacement of a z axis of the set coordinate system with respect to a vertical axis, the operation program is for operating the robot. 5. A method for setting a coordinate system of a robot, the method comprising:
a step of installing a robot on a reference flat surface; a flat-surface-position measuring step of measuring at least position coordinates in a vertical direction of three or more measurement points on the reference flat surface; a reflection-portion-position measuring step of measuring position coordinates of a plurality of reference reflection portions provided on a base portion of the robot; and a coordinate system setting step of setting a coordinate system of the robot, installed on the reference flat surface, using the position coordinates of the measurement points on the reference flat surface and the position coordinates of the reference reflection portions. 6. The method for setting a coordinate system of a robot according to in the coordinate system setting step, a robot control unit receives the position coordinates on the reference flat surface and the position coordinates of the reference reflection portions from a position measuring apparatus which uses a laser beam, and the robot control unit sets the coordinate system using the received position coordinates. 7. The method for setting a coordinate system of a robot according to CROSS-REFERENCE TO RELATED APPLICATIONS
FIELD OF THE INVENTION
BACKGROUND OF THE INVENTION
SUMMARY OF THE INVENTION
BRIEF DESCRIPTION OF THE DRAWINGS
DESCRIPTION OF EMBODIMENT(S) OF THE INVENTION




