Method for measuring installation position of robot, robot control device, teaching system, and simulation device

Abstract

A robot installation position measurement device (1) comprises: a first position information acquisition unit (2) that acquires first position information, which is a three-dimensional command position for the end point of a tool fixed to a flange at the tip end of a robot, in a state where the robot is positioned in an arbitrary orientation; a second position information acquisition unit (3) that acquires, in the arbitrary orientation, second position information, which is the actual three-dimensional position of the end point of the tool, using a three-dimensional measurement apparatus placed in a prescribed measurement coordinate system; and a coordinate system correcting unit (4) that corrects a robot coordinate system, on the basis of which the robot operates, so as to reduce the difference between the first position information and the second position information each having been acquired with the robot positioned in a plurality of different orientations.

Description

[Technical field]

[0001] The present disclosure relates to a robot installation position measuring device, an installation position measuring method, a robot control device, a teaching system, and a simulation device. [Background technology]

[0002] There is known a robot system that sets the coordinate system of the robot using a three-dimensional measuring device such as a laser tracker (see, for example, Patent Document 1). This robot system sets the coordinate system of the robot installed on a reference plane based on the measurement results of at least the vertical position coordinates of three or more measurement points on a reference plane on which the robot is installed, and the measurement results of the position information of multiple reference reflectors provided at the base of the robot.

[0003] According to this robot system, the coordinate system of the actually installed robot can be obtained by measurement, and for example, the coordinate system of the robot ideally set in an offline simulation can be corrected to the actual coordinate system. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2019-77016 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, when the production cell is complex, it may be difficult to measure the position information of the measurement points on the reference plane on which the robot is installed and the reference reflector provided at the base of the robot using a three-dimensional measuring device due to the presence of peripheral devices, etc. Therefore, even when it is difficult to measure the measurement points on the reference plane or the reference reflector provided at the base of the robot using a three-dimensional measuring device, it is desirable to set the coordinate system of the robot with high accuracy. [Means for solving the problem]

[0006] One aspect of the present disclosure includes a first position information acquisition unit that acquires first position information, which is a three-dimensional command position of a tool tip point fixed to a flange at the tip of a robot, when the robot is positioned in an arbitrary posture, and a three-dimensional measuring device installed in a predetermined measurement coordinate system in the posture. Based on the output from a second position information acquisition unit that acquires second position information that is a three-dimensional actual position of the tool tip point; a parameter storage unit that stores a plurality of error parameters used to calculate the position of the tool tip point from a command value for the robot to realize the command position, and a coordinate system correction unit that corrects a robot coordinate system based on the plurality of error parameters so as to reduce a difference between the first position information and the second position information acquired in a state in which the robot is positioned in a plurality of different postures. It is. [Brief description of the drawings]

[0007] [Figure 1] 1 is an overall configuration diagram showing a robot system including an installation position measurement device according to an embodiment of the present disclosure. [Diagram 2] FIG. 2 is a block diagram showing a robot control device that controls a robot in the robot system of FIG. [Diagram 3] 2 is a side view showing a position measuring device provided in the robot system of FIG. 1. [Figure 4] FIG. 4 is a block diagram showing a measurement control device that controls the position measuring device of FIG. 3. [Diagram 5] FIG. 2 is a block diagram showing the installation position measurement device of FIG. 1. [Figure 6] 1 is an explanatory diagram of a coordinate system and a homogeneous transformation matrix for explaining an installation position measurement method according to an embodiment of the present disclosure. [Figure 7] 7 is a flowchart illustrating the installation position measurement method of FIG. 6. [Figure 8] FIG. 1 is a block diagram showing a robot control device according to an embodiment of the present disclosure. [Figure 9] FIG. 6 is a block diagram showing a modified example of the installation position measurement device of FIG. [Figure 10] 13 is an example of a display screen illustrating a teaching system according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] A robot installation position measuring device 1 and an installation position measuring method according to an embodiment of the present disclosure will be described below with reference to the drawings. The robot installation position measuring device 1 of this embodiment is provided in a robot system (teaching system) 100 which includes a robot 20, a robot control device 30 which controls the robot 20, a simulation device 40, and a position measuring device (three-dimensional measuring device) 50, as shown in FIG.

[0009] The robot 20 performs a predetermined task such as spot welding on a workpiece (not shown), and is equipped with a plurality of drive shafts and a plurality of servo motors 11 for driving each drive shaft. Various types of servo motors such as rotary motors and linear motors can be used as each servo motor 11. Each servo motor 11 has a built-in operating position detection device such as an encoder that detects its operating position, and the detection value of the operating position detection device is transmitted to the robot control device 30. A processing tool (tool) 22 is attached to a flange 21 disposed at the tip of the robot 20.

[0010] 2, the robot control device 30 includes, for example, a robot control unit 31 having a CPU, RAM, etc., a display device 32, and a storage device 33 having a non-volatile storage, ROM, etc. The robot control device 30 also includes a plurality of servo controllers 34 provided corresponding to the servo motors 11, respectively, and a teaching operation panel 35 connected to the robot control device 30 and portable by the operator. Furthermore, the teaching pendant 35 may be provided separately from the robot controller 30 and may be configured to communicate with the robot controller 30 wirelessly.

[0011] The storage device 33 stores a system program 33a, which performs the basic functions of the robot control device 30. The storage device 33 also stores at least one operation program 33b created using a simulation device 40. Specifically, a three-dimensional model of the robot 20 and a model of a workpiece are created on the simulation device 40, and an operation program 33b is created for welding a plurality of welding points while avoiding interference between the robot 20 and the workpiece, for example.

[0012] The robot control unit 31 operates according to a system program 33a, reads out an operation program 33b stored in the storage device 33, and temporarily stores it in the RAM. Then, in accordance with the read operation program 33b, it sends control signals to a servo controller 34 to control the servo amplifiers of the servo motors 11 of the robot 20. The robot control unit 31 generates command values ​​so that the commanded positions of the flange center or tool tip point required in the operation program 33b are achieved based on a preset robot coordinate system.

[0013] 3, the position measuring device 50 includes a laser head 51 and a head driving unit 52. The laser head 51 emits laser light toward a reflecting member fixed to the tip of the tool and receives the light reflected from the reflecting member. The reflecting member is a spherical reflector that is fixed to the tip of the tool when measuring the installation position of the robot 20.

[0014] The head driving unit 52 includes a vertical axis motor 53 and a horizontal axis motor 54 for changing the orientation of the laser head 51. The vertical axis motor 53 rotates the laser head 51 and the horizontal axis motor 54 about a vertical axis. The horizontal axis motor 54 rotates the laser head 51 about a horizontal axis.

[0015] The vertical axis motor 53 and the horizontal axis motor 54 are connected to and controlled by the measurement control device 60. The vertical axis motor 53 and the horizontal axis motor 54 each have an operating position detection device, such as an encoder, built in to detect their operating positions, and the detection value of the operating position detection device is sent to the measurement control device 60.

[0016] The laser head 51 is provided with a laser light emitting unit 51a, and a laser light from a laser oscillator (not shown) is emitted from the laser light emitting unit 51a. A light receiving sensor 51b that receives reflected light reflected by a reflecting member or the like is provided inside the laser light emitting unit 51a of the laser head 51. The laser head 51 is connected to a measurement control device 60, which controls the emission of laser light from the laser light emitting unit 51a of the laser head 51, and transmits the detection result by the light receiving sensor 51b to the measurement control device 60.

[0017] 4, the measurement control device 60 includes, for example, a control unit 61 having a CPU, RAM, etc., a display device 62, a storage device 63 having a non-volatile storage, ROM, etc., and an input device 64. The input device 64 may be configured to communicate with the measurement control device 60 wirelessly. The storage device 63 stores a system program 63 a, which performs the basic functions of the measurement control device 60 . Furthermore, the measurement control device 60 may be built into the position measuring device 50 or may be provided at a location other than the position measuring device 50 .

[0018] The simulation device 40 is configured with a computer and stores three-dimensional models of one or more robots 20, machining tools 22, workpieces, peripheral devices, etc. The simulation device 40 can create an operation program by teaching the positions of multiple teaching points, operation speeds, etc. while moving the three-dimensional models of the robot 20 and machining tools 22 relative to the three-dimensional model of the workpiece. The simulation device 40 also executes the created operation program to operate the three-dimensional models of the robot 20 and machining tools 22 in accordance with the operation program, and can simulate interference checks, measurement of takt time, etc.

[0019] In the simulation device 40, as a premise for creating an operation program, the robot 20 is installed at the origin of the designed robot coordinate system R0, with the x direction of the robot coordinate system R0 precisely aligned with the front direction of the robot 20. The position measuring device 50 is also set at the origin of the designed measurement coordinate system L0, which is set with respect to the origin of the designed robot coordinate system R0 described above. Furthermore, the size and shape of the machining tool 22 attached to the flange 21 of the robot 20 are set based on the design values, and a designed tool coordinate system T0 as viewed from the flange coordinate system F0 is set.

[0020] The installation position measuring device 1 according to this embodiment is a device equipped with a CPU, RAM, etc., and is connected to a robot control device 30, a simulation device 40, and a position measuring device 50, as shown in FIG. As shown in FIG. 5, the installation position measuring device 1 includes a first position information acquiring section 2, a second position information acquiring section 3, and a coordinate system correcting section 4.

[0021] The first position information acquisition unit 2 commands the robot control device 30 to operate and position the robot 20 in a plurality of postures, and acquires position information (first position information) of the commanded position of the tool tip point in each posture commanded by the robot control device 30. At this point, the robot coordinate system (robot coordinate system, world coordinate system) in which the robot 20 operates is a designed coordinate system set in the simulation device 40, and the commanded position is also designed position information calculated based on the design values.

[0022] The second position information acquisition unit 3 commands the measurement control device 60 to operate the position measuring device 50 to measure the three-dimensional position of the reflecting member placed at the tool tip point of the actual robot 20, and acquires the measured position information (second position information) from the position measuring device 50. The position information acquired at this point is the actual position information of the tool tip point as viewed from the measurement coordinate system (unknown) in which the actual position measuring device 50 is set.

[0023] The coordinate system correction unit 4 corrects the robot coordinate system based on the position information of the command position of the tool tip point acquired by the first position information acquisition unit 2 and the actual position information of the tool tip point acquired by the second position information acquisition unit 3 in the following manner. 6, as described above, the position and orientation of the design measurement coordinate system L0 as viewed from the design robot coordinate system R0 are preset in the simulation device 40. UF It is expressed using:

[0024] In addition, the flange coordinate system F0 as viewed from the designed robot coordinate system R0 and the designed tool coordinate system T0 installed at the tool tip point are also transformed by the homogeneous transformation matrix A R , A UT It can be expressed as: In addition, the position and orientation of the actual measurement coordinate system L1 are unknown, but there is usually an error between the design measurement coordinate system L0 and the actual measurement coordinate system L1. The actual measurement coordinate system L1 as seen from the design measurement coordinate system L0 is transformed into a homogeneous transformation matrix A. ΔUF It can be expressed as:

[0025] Furthermore, there is usually an error between the design tool coordinate system T0 and the real tool coordinate system T1. The real tool coordinate system T1 seen from the design tool coordinate system T0 is transformed by the homogeneous transformation matrix A ΔUT It can be expressed as: Then, by using these homogeneous transformation matrices, the following equation (1) is established. P=A -1 ΔUF (A -1 UF A R )A UT A ΔUT (1) Here, P is a homogeneous transformation matrix calculated from the command position of the design tool tip point as viewed from the design measurement coordinate system L0, A -1 ΔUF , A -1 UF are A ΔUF , A UF is the inverse matrix of

[0026] The actual position information of the tool tip point as viewed from the actual measurement coordinate system L1 is acquired by the position measuring device 50. The coordinate system correction unit 4 moves the robot 20 to a plurality of postures, calculates the difference between the position information of the command position of the tool tip point obtained by the formula (1) in each posture and the actual position information obtained by the position measuring device 50, and selects the homogeneous transformation matrix A that reduces the difference (for example, minimizes the difference). ΔUF ,A ΔUT Identify.

[0027] And the homogeneous transformation matrix A obtained in this way ΔUF By using this, the real measurement coordinate system L1 seen from the real robot coordinate system is transformed into the homogeneous transformation matrix A new_UF is obtained by A new_UF =A UF A ΔUF (2)

[0028] Therefore, the real robot coordinate system seen from the real measurement coordinate system L1 is expressed by the homogeneous transformation matrix A new_UF It can be obtained by calculating the inverse matrix of The coordinate system correction unit 4 sends the corrected robot coordinate system thus obtained to the simulation device 40, and corrects the designed robot coordinate system R0 set in the simulation device 40 by replacing it with the corrected robot coordinate system.

[0029] Then, by performing an offline simulation of the operation program in the simulation device 40 using the corrected actual robot coordinate system, the operation program can be corrected so that the robot 20 and machining tool 22 do not interfere with the workpiece or peripheral equipment.

[0030] An installation position measuring method using the installation position measuring device 1 according to this embodiment configured as above will be described below. 7, in the installation position measuring method according to this embodiment, the number of measurements k is initialized (step S1), and the robot control device 30 controls the robot 20 based on a command from the first position information acquisition unit 2 to position it in an arbitrary posture (step S2). First position information consisting of the commanded position of the tool tip point at this time is sent from the robot control device 30 to the first position information acquisition unit 2 and stored therein (step S3).

[0031] Next, in the attitude determined in step S2, the measurement control device 60 controls the position measuring device 50 based on a command from the second position information acquisition unit 3 to measure the position of the tool tip point (step S4). Second position information consisting of the measured position information of the tool tip point is sent to the second position information acquisition unit 3 and stored therein (step S5).

[0032] Next, it is determined whether the measurement count k has reached the designated count N0 (step S6), and if the measurement count k has not reached the designated count N0, the measurement count k is incremented (step S7), and the process from step S2 is repeated. The designated count N0 is, for example, N0=3. When the number of measurements k reaches the designated number of measurements N0, all the stored first position information and second position information are sent to the coordinate system correction unit 4, and the robot coordinate system is corrected in the coordinate system correction unit 4 (step S8).

[0033] Thus, according to the installation position measuring device 1 and installation position measuring method of this embodiment, the robot coordinate system can be corrected by positioning the robot 20 in a plurality of postures and measuring the position of the reflecting member fixed to the tool tip point. Therefore, unlike the conventional method that uses a measuring point on a reference plane on which the robot 20 is installed and a reflecting part provided at the base of the robot 20, there is an advantage that the robot coordinate system can be easily corrected without being disturbed by peripheral devices even when the production cell is complicated.

[0034] In this embodiment, the coordinate system correction unit 4 uses a homogeneous transformation matrix A that reduces the difference between the first position information and the second position information. ΔUF ,A ΔUT For example, if the actual measurement coordinate system L1 precisely matches the design measurement coordinate system L0, or the actual tool coordinate system T1 precisely matches the design tool coordinate system T0, it is sufficient to identify only one of them.

[0035] In the present embodiment, the command position of the tool tip point has been exemplified as the first information that the first position information acquisition unit 2 receives from the robot control device 30. Alternatively, the first position information acquisition unit 2 may acquire the first position information by receiving the origin position of the flange coordinate system F0 from the robot control device 30 and calculating the position of the tool tip point.

[0036] In addition, in this embodiment, an example has been shown in which the installation position measuring device 1 is provided separately from the robot control device 30, but instead, as shown in FIG. 8, the installation position measuring device 1 may be provided in the robot control device 30. In this case, the robot control device 30 may include a parameter storage unit 36 ​​that stores a plurality of error parameters used to calculate an accurate position of the tool tip point from a command value for the robot 20, and a mechanical error correction unit 37 that corrects mechanical errors by a known method using the error parameters stored in the parameter storage unit 36. Examples of mechanical errors include Denavit-Hartenberg parameters (DH parameters) or gravity springs.

[0037] The robot control unit 31 corrects the mechanical error using the error parameters by the mechanical error correction unit 37, and generates command values ​​such that the calculated command position becomes the command position required by the operation program. This improves the accuracy of the command values ​​acquired from the robot control unit 31 when correcting the robot coordinate system, and makes it possible to obtain a more accurate robot coordinate system. The correction of the mechanical error may be performed in advance by calibration, or may be performed by a mechanical error correction unit 37 provided in the robot control device 30 at the same time as the calibration of the tool coordinate system and the robot coordinate system.

[0038] In this embodiment, the degree of dependency between the error parameters is determined in the coordinate system correction unit 4, and if it is determined that the degree of dependency is high, identification of the corresponding vector in the tool coordinate system may not be performed. The error parameters related to the measurement of the installation position of the robot 20 are the correction values ​​(x a ,y a ,z a ,w a ,p a ,r a ) and the tool vector correction value (x b ,y b ,z b ) are the nine. If the vector whose elements are these error parameters is denoted as q, the vector p indicating the three-dimensional position of the tool tip point can be expressed as follows using a function f that takes the error model into account. p = f(q)

[0039] The vector Δp indicating the deviation amount between the commanded position information of the tool tip point and the measured actual position information can be approximated by the sum of linear combinations of minute fluctuations of each error parameter. Note that JA is the Jacobian. Δp=(∂p / ∂q)·Δq=JA·Δq

[0040] Since the laser tracker performs three-dimensional measurement, three equations are established from one measurement posture. When these are extended to a plurality of measurement postures, a vector Δr indicating the corresponding deviation amount and a Jacobian D are obtained and can be expressed as follows. Δr=D·Δq

[0041] Generally, the error parameters are identified by solving the iterative estimation problem that minimizes Δr. Assuming that the number of equations is N and the number of error parameters is M, the Jacobian D is given as follows.

[0042]

Equation

[0043] When the number of equations is larger than the number of unknowns, a general least squares problem can be solved by transforming [D]{p}={q} into [D] T [D]{p}=[D] T {q} and obtaining the following equation.

[0044]

Equation

[0045] [D] T [D] becomes an M×M matrix. The determination of the degree of membership calculates the inner product Q of the unit vectors of each column vector of this [D] T [D], and for example, when 0.9<Q≦1, it can be determined that the degree of membership is high.

[0046] For example, if the z-axis directions of the measurement coordinate system and the tool coordinate system are the same and each measurement attitude is rotated only around the Z axis of the tool coordinate system, the z components of the measurement coordinate system and the tool coordinate system are in a dependent relationship. For example, if the correction amount of the z component of the measurement coordinate system is the first error parameter and the correction amount of the z component of the tool coordinate system is the second error parameter, then the above-mentioned [D] T The inner product Q of the vector in the first column and the unit vector in the second column of [D] satisfies the above condition. When the degree of dependency is high, the coordinate system correction unit 4 does not identify the corresponding vector in the tool coordinate system, that is, does not calculate the correction amount of the z component of the tool coordinate system.

[0047] When the processing tool 22 fixed to the flange 21 of the robot 20 is, for example, a servo gun having an equalizing mechanism, the position of the tool tip point changes due to its own weight when the attitude of the tool is changed in the z-axis direction of the tool coordinate system, which is the pressure direction. If the position of the tool tip point changes, the error increases and the calculation accuracy deteriorates, so in the operation of the robot 20 when correcting the robot coordinate system, the servo gun is positioned in multiple attitudes that keep the position of the tool tip point from changing due to its own weight.

[0048] In such a case, the z component of the tool coordinate system and the z component of the measurement coordinate system are almost in the same direction, and the degree of dependency is high. When the degree of dependency is high, it becomes difficult to distinguish whether the z component of the tool coordinate system or the z component of the measurement coordinate system should be corrected, so the two homogeneous transformation matrices A ΔUF ,A ΔUT Therefore, when it is determined that the degree of dependency is high, the calculation of the z-axis direction of the tool coordinate system is not performed, and the drawing value or the advance measurement value is used to set the robot coordinate system with high accuracy.

[0049] Or, [D] TIt is also possible to exclude error parameters with small eigenvalues ​​from the error parameter group until the ratio of the maximum eigenvalue to the minimum eigenvalue in [D] reaches a certain constant value. This makes it possible to detect, for example, that the measurement postures are significantly adjacent to each other and the correction amount of the measurement coordinate system cannot be calculated with high accuracy, and to notify the user in advance.

[0050] Jacobian D can be calculated before obtaining position information by measurement, and by using Jacobian D, it is possible to know which error parameters will be calculated before starting measurement. By knowing in advance when a component of the tool coordinate system that you want to calculate cannot be calculated or cannot be calculated with high accuracy, you can consider the measurement posture in advance.

[0051] In this embodiment, the installation position measuring device 1 may include a tool coordinate system output unit 5 as shown in FIG. After the robot coordinate system has been corrected by the coordinate system correction unit 4, the tool coordinate system output unit 5 positions the robot 20 in any one of the postures, calculates the tool coordinate system by the following method, and outputs it.

[0052] That is, the tool coordinate system output unit 5 receives the robot coordinate system corrected in the coordinate system correction unit 4. Then, the tool coordinate system output unit 5 calculates the position of the tool coordinate system based on the command position (first position information) of the origin of the flange coordinate system acquired from the robot control device 30 and the actual position (second position information) of the tool tip point acquired from the position measuring device 50.

[0053] After the robot coordinate system is corrected, the robot coordinate system and the measurement coordinate system are corrected with high accuracy, so the homogeneous transformation matrix A of the measurement coordinate system seen from the robot coordinate system is UF becomes known. In addition, the homogeneous transformation matrix A of the flange coordinate system as viewed from the robot coordinate system R can also be calculated with high accuracy based on the command position acquired from the robot control device 30.

[0054] Then, the homogeneous transformation matrix P is obtained based on the actual tool tip point seen from the measurement coordinate system obtained from the position measuring device 50, and the homogeneous transformation matrix A of the tool coordinate system seen from the origin of the flange coordinate system is obtained by the formula (3). UT can be calculated. A UT =A -1 R A UF P (3)

[0055] The tool coordinate system output unit 5 calculates the homogeneous transformation matrix A UT Only the position components of the tool 22 are extracted and output. This allows the tool coordinate system to be output with the robot 20 positioned in one posture, shortening the required time. Also, when the tool coordinate system changes due to a change in the posture of the machining tool 22, it may be necessary to create a table of the tool coordinate system according to the tool posture. In such cases, there is an advantage in that the tool coordinate system can be obtained for each desired posture.

[0056] Even when the tool coordinate system is calculated by the tool coordinate system output unit 5, if the robot control device 30 corrects the mechanical error using the error parameters, a more accurate command value can be obtained, and a more accurate tool coordinate system can be obtained.

[0057] Next, a teaching system 100 according to an embodiment of the present disclosure will be described below with reference to the drawings. The teaching system 100 according to this embodiment is configured by a robot system including the above-mentioned robot 20, a robot control device 30 that controls the robot 20, a simulation device 40, a position measuring device (three-dimensional measuring device) 50, and an installation position measuring device 1. The simulation device 40 includes a display device (update unit) 41 such as a display, and an input device (update unit) such as a mouse or a keyboard (not shown).

[0058] FIG. 10 shows an example of a display on the display screen of the display device 41 of the simulation device 40. In FIG. 10, a setting button for setting a measurement coordinate system of the position measuring device 50, which is a three-dimensional measuring device, is displayed on the left side of the display screen. The operator can input information about the measurement coordinate system by pressing the measurement coordinate system setting button.

[0059] At the center of the display screen shown in FIG. 10, buttons indicating operations for the robot control device 30 or the teaching pendant 35 are displayed. By pressing the button "Open installation position measurement screen", an installation position measurement screen is displayed on the display device 32 of the robot control device 30. By pressing the "Coordinate system settings" button, it is possible to enable / disable calculation of the tool coordinate system, enable / disable calculation of the robot coordinate system, input the designed robot coordinate system and tool coordinate system, set the load, etc.

[0060] By pressing the "Program Selection" button, a program to be operated by the robot 20 when measuring the installation position can be specified. When a program is specified, the specified program is converted into a measurement program in which measurement commands by the 3D measuring device are added after each operation line.

[0061] By pressing the "Execute" button, the robot control device 30 operates the robot 20 based on the set measurement program, and the installation position measuring device 1 calculates a corrected robot coordinate system.

[0062] An "error display section 42" is located in the upper right-hand portion of the display screen shown in Fig. 10, which displays error information between the robot coordinate system corrected by the installation position measuring device 1 and the robot coordinate system before correction. The error information displayed in the error display section 42 may be displayed as a numerical value, or may be displayed by superimposing figures of the robot coordinate systems before and after correction.

[0063] At the lower right side of the display screen shown in FIG. 10, a model display section 43 is provided that displays a three-dimensional model of the robot 20 etc. acquired from the simulation device 40. On this display screen, the error information displayed in the error display section 42 can be moved (applied) to the model display section 43, for example, by dragging it with the mouse. This allows the display of the 3D model of the robot 20 in which the pre-correction robot coordinate system is set, which is displayed in the model display section 43, to be updated to the display of the 3D model of the robot 20 in which the corrected robot coordinate system is set.

[0064] Furthermore, instead of or in addition to updating the display in the model display unit 43, the error information may be used to update the operation program created offline in the simulation device 40. That is, the simulation device 40 includes a reception unit that receives error information of the robot coordinate systems before and after the correction, and the received error information is applied to the operation program created in the simulation device 40 based on the designed robot coordinate system R0, thereby updating the operation program to one based on the corrected robot coordinate system.

[0065] Specifically, the positions of the teaching points of the motion program created based on the robot coordinate system before correction are shifted based on the error information of the robot coordinate system. The motion program updated in this way can be executed offline in a simulation device to check the motion, such as by checking for interference.

[0066] 10, the operation program updated in the simulation device 40 is loaded into the robot control device 30. This makes it possible to operate the robot 20 using the operation program whose operation has been confirmed offline using a 3D model.

[0067] In the explanation of this teaching system 100, the display screen of FIG. 10 is displayed on a display device 41 provided in the simulation device 40, but instead, it may be displayed on a display device attached to another computer. Further, although the installation position measuring device 1 is disposed separately from the robot control device 30, the installation position measuring device 1 may be built into the robot control device 30. [Explanation of symbols]

[0068] 1 Installation position measuring device 2 First location information acquisition unit 3 Second location information acquisition unit 4 Coordinate system correction part 5 Tool coordinate system output Department 2 0 Robots 21 Flange 30 Robot control device 36 Parameter storage section 37 Mechanical error correction section 40 Simulation Device 41 Display device (update section) 42 Error display section 43 Model display section 50 Position measuring device (3D measuring device) 100 Robot System (Teaching System) F0 flange coordinate system L0,L1 measurement coordinate system R0 robot coordinate system T0, T1 tool coordinate system

Claims

1. a first position information acquisition unit that acquires first position information, which is a three-dimensional command position of a tool tip point fixed to a flange at a tip of the robot, with the robot positioned in an arbitrary posture; a second position information acquisition unit that acquires second position information, which is a three-dimensional actual position of the tool tip point, based on an output from a three-dimensional measuring device installed in a predetermined measurement coordinate system in the attitude; a parameter storage unit configured to store a plurality of error parameters used to calculate the position of the tool tip point from a command value for the robot to realize the command position; a coordinate system correction unit that corrects a robot coordinate system based on the plurality of error parameters so as to reduce a difference between the first position information and the second position information acquired while the robot is positioned in a plurality of different postures; A robot control device comprising:

2. 2. A robot control device as described in claim 1, wherein the coordinate system correction unit identifies at least one of a tool coordinate system that defines the position and orientation from an origin of a flange coordinate system fixed to the flange to the tool tip point and the measurement coordinate system viewed from the origin of the robot coordinate system, so as to reduce the difference between the first position information and the second position information, and corrects the robot coordinate system based on the identified tool coordinate system and / or the measurement coordinate system.

3. The robot control device according to claim 2 , wherein the coordinate system correction unit simultaneously identifies both the tool coordinate system and the measurement coordinate system so that the difference between the first position information and the second position information becomes small.

4. The robot control device according to claim 3 , wherein the coordinate system correction unit determines the degree of dependence of vectors defining the orientations of the tool coordinate system and the measurement coordinate system, and does not identify vectors determined to have a high degree of dependence.

5. 5. A robot control device according to claim 2, further comprising a tool coordinate system output unit (5) that, while the robot is positioned in an arbitrary posture, calculates and outputs the tool coordinate system based on a command position of the origin of the flange coordinate system as seen from the robot coordinate system corrected by the coordinate system correction unit and an actual position of the tool tip point acquired by the three-dimensional measuring device.

6. 6. The robot control device according to claim 1, further comprising a mechanical error correction unit that corrects mechanical errors of the robot using the error parameters stored in the parameter storage unit.

7. A robot controller according to any preceding claim, wherein the measurement coordinate system is not positioned relative to the robot coordinate system.

8. positioning the robot in two or more poses; acquiring first position information, which is a three-dimensional command position of a tool tip point fixed to a flange at the tip of the robot, in each of the postures; acquiring second position information, which is a three-dimensional actual position of the tool tip point, based on an output from a three-dimensional measuring device installed in a predetermined measurement coordinate system in each of the orientations; and correcting a robot coordinate system, which is a reference for the operation of the robot, so that a difference between the acquired first position information and the acquired second position information becomes smaller, based on a plurality of error parameters used for calculating the position of the tool tip point from a command value for the robot to realize the command position.

9. 9. The robot installation position measuring method according to claim 8, wherein correcting the robot coordinate system includes identifying at least one of a tool coordinate system that defines the position and orientation from an origin of a flange coordinate system fixed to the flange to the tool tip point and the measurement coordinate system viewed from the origin of the robot coordinate system so as to reduce the difference, and correcting the robot coordinate system based on the identified tool coordinate system and / or the measurement coordinate system.

10. The method for measuring a robot's installed position according to claim 9 , wherein correcting the robot coordinate system includes simultaneously identifying both the tool coordinate system and the measurement coordinate system such that the difference is small.

11. The method for measuring the installation position of a robot according to claim 10, wherein the correction of the robot coordinate system includes determining the degree of dependence of vectors defining the orientations of the tool coordinate system and the measurement coordinate system, and not identifying vectors determined to have a high degree of dependence.

12. 12. The method for measuring a robot installation position according to claim 8, wherein the measurement coordinate system is not positioned relatively to the robot coordinate system.

13. A robot control device according to any one of claims 1 to 7, a simulation device capable of creating an operation program offline based on a three-dimensional model of the robot; a model display unit capable of displaying a three-dimensional model of the robot; an error display unit that displays error information representing an error between a robot coordinate system before correction set in the simulation device and a robot coordinate system corrected in the robot control device; and an update unit that updates at least one of the display of the three-dimensional model on the model display unit and the operation program stored in the simulation device based on the error information by applying the error information displayed on the error display unit to the three-dimensional model displayed on the model display unit.

14. A simulation device capable of creating an operation program offline based on a three-dimensional model of a robot, a model display unit capable of displaying a three-dimensional model of the robot; an error display unit that displays error information representing an error in the robot coordinate system; and an update unit that updates at least one of the display of the three-dimensional model in the model display unit and the operation program based on the error information by dragging the error information displayed in the error display unit to the three-dimensional model displayed in the model display unit and applying the error information.

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