WO2024057764A1

WO2024057764A1 - Robot system

Info

Publication number: WO2024057764A1
Application number: PCT/JP2023/028433
Authority: WO
Inventors: 洸太川村
Original assignee: パナソニックＩｐマネジメント株式会社
Priority date: 2022-09-16
Filing date: 2023-08-03
Publication date: 2024-03-21

Abstract

A robot system according to the present invention comprises: a robot having a plurality of operation shafts; a robot control device that moves each of the plurality of operation shafts and adjusts the orientation of each of the operation shafts; an acceleration sensor that is provided at the leading end portion of the robot and measures the gravitational acceleration at the leading end portion; and a terminal device that can communicate between the acceleration sensor and the robot control device. The robot control device moves the orientation of a first operation shaft to at least three or more different orientations. The terminal device stores three or more pieces of first gravitational acceleration data detected by the acceleration sensor at each of the three or more orientations, calculates a first rotation axis vector of the first operation shaft in a three-dimensional space on the basis of the three or more pieces of first gravitational acceleration data, and calculates, on the basis of the calculated first rotation axis vector, a correction parameter for correcting an orientation deviation of the robot.

Description

robot system

The present disclosure relates to a robot system.

Patent Document 1 describes a calibration method for a robot equipped with an arm having six or more degrees of freedom so that the tip can be positioned in any desired position and posture by applying force to the tip and moving the tip. A method is disclosed. This robot calibration method uses a three-dimensional measuring device that can measure the position and orientation of the tip by installing position detectors on each axis of the joints of the arm and measuring the position and orientation of the tip from the signals from the position detectors of each axis. Then, connect the tip of the 3D measuring instrument to the hand at the tip of the articulated robot you want to calibrate, measure the position and orientation of the robot tip, and change the position and orientation of the robot to measure multiple teaching points. Calibration is performed by measuring.

Japanese Patent Application Publication No. 2001-50741

The present disclosure provides a robot system that adjusts the posture of each joint of a robot with higher precision.

The present disclosure provides a robot having a plurality of motion axes, a robot control device that operates each of the plurality of motion axes to adjust the posture of the motion axis, and a robot control device that is provided at a tip of the robot, and that is provided at a tip of the robot. A robot system comprising: an acceleration sensor that measures gravitational acceleration at a position; and a terminal device capable of communicating between the acceleration sensor and the robot control device, wherein the robot control device measures the gravitational acceleration of each of the plurality of motion axes. The terminal device moves the posture of any one of the first motion axes to at least three different postures, and the terminal device moves the posture of any one of the first motion axes to at least three different postures, and the terminal device storing gravitational acceleration data, calculating a first rotational axis vector of the first motion axis in three-dimensional space based on the three or more stored first gravitational acceleration data, and calculating the calculated first rotation; A robot system is provided that calculates a correction parameter for correcting the posture deviation of the robot based on an axis vector.

According to the present disclosure, the posture of each joint of the robot can be adjusted with higher precision.

A block diagram showing an example of a system configuration of a robot system according to an embodiment. A diagram showing an example of six joint axes of the robot in the embodiment A diagram explaining the six rotational axis vectors of the robot and the coordinate system of the three-dimensional acceleration sensor in the embodiment Flowchart illustrating an example of the operation procedure of the robot system according to the embodiment Flowchart illustrating an example of a procedure for measuring gravitational acceleration of a robot system according to an embodiment Flowchart illustrating an example of a procedure for measuring gravitational acceleration of a robot system according to an embodiment Flowchart illustrating an example of a procedure for calculating a rotation axis vector of a terminal device in an embodiment Diagram explaining an example of a plane and a circle Diagram explaining an example of a circle estimation process procedure Diagram explaining example 1 of setting the rotation axis vector Diagram explaining example 2 of setting the rotation axis vector Diagram explaining example 3 of setting the rotation axis vector Diagram explaining an example of detecting the inclination of the robot installation surface Diagram illustrating an example of detecting joint axis misalignment Diagram explaining an example of wrist axis origin adjustment A diagram explaining an example of the angular difference Φ _RW and Φ _TW

(Circumstances leading to this disclosure)
Robots are shipped with each joint axis calibrated, but if the tip of the robot collides with an obstacle or parts of the robot are replaced, the position and posture of the joint axes may change. Misalignment occurs. Therefore, as in Patent Document 1, a robot calibration method using a three-dimensional position measuring device that can measure joint angles with high precision is disclosed, but the three-dimensional position measuring device is expensive and difficult to measure. Requires work space. In addition, the operator had to install a position detector at each joint of the robot and connect the hand of the multi-joint robot to the tip of the three-dimensional measuring device at a predetermined position, which was very time-consuming.

In addition, conventional methods for calibrating other robots include attaching pins for positioning to the tip of the robot and aligning the pins with positioning points on a jig to calibrate the robot. be. However, such a calibration method has a problem in that the calibration accuracy depends on the skill level of the operator who performs the alignment.

Hereinafter, each embodiment specifically disclosing the robot system according to the present disclosure will be described in detail with reference to the drawings as appropriate. However, more detailed explanation than necessary may be omitted. For example, detailed explanations of well-known matters or redundant explanations of substantially the same configurations may be omitted. This is to avoid unnecessary redundancy in the following description and to facilitate understanding by those skilled in the art. The accompanying drawings and the following description are provided to enable those skilled in the art to fully understand the present disclosure, and are not intended to limit the subject matter recited in the claims.

First, the overall configuration of a robot system 100 according to an embodiment will be described with reference to FIGS. 1 and 2, respectively. FIG. 1 is a block diagram showing an example of a system configuration of a robot system 100 according to an embodiment. FIG. 2 shows six joint axes (one example of the motion axes) of the robot M1 in the embodiment, including the RT joint axis J1, the UA joint axis J2, the FA joint axis J3, the RW joint axis J4, the BW joint axis J5, and the TW joint axis. It is a figure showing an example of joint axis J6).

The robot system 100 according to the embodiment includes a terminal device P1, a robot control device R1, and a robot M1.

The terminal device P1 is realized by, for example, a PC (Personal Computer), a notebook PC, a tablet terminal, or the like. The terminal device P1 is capable of receiving an operator's operation for calibrating the robot M1, and is configured to calibrate the at least one joint axis of the robot M1 based on the measured value of the gravitational acceleration of the at least one joint axis of the robot M1. Calculate correction parameters. The terminal device P1 includes a first communication section 10, a first processor 11, a first memory 12, an input section 13, and a display section 14.

The first communication unit 10 is connected to a three-dimensional acceleration sensor 31 attached to the robot M1 for wireless or wired communication, and executes data transmission and reception. Note that the wireless communication referred to here is communication via a wireless LAN (Local Area Network) such as Wi-Fi (registered trademark), for example. The first communication unit 10 outputs the gravitational acceleration information transmitted from the three-dimensional acceleration sensor 31 to the first processor 11.

The first processor 11 is configured using, for example, a CPU (Central Processing Unit) or an FPGA (Field Programmable Gate Array), and performs various processing and control in cooperation with the first memory 12. Specifically, the first processor 11 refers to a program held in the first memory 12 and executes the program to realize the functions of each part. Note that each section referred to here includes a rotational axis vector calculation section 111, a correction parameter calculation section 112, a measurement posture command section 113, and the like. The first processor 11 calculates a correction parameter for correcting (adjusting) the posture of at least one joint axis based on the posture (gravitational acceleration) of the robot M1 measured by the three-dimensional acceleration sensor 31.

The rotational axis vector calculation unit 111 calculates the rotational axis vector of one joint axis based on each of the measured values of gravitational acceleration measured in three or more different postures with respect to this joint axis. Note that the rotational axis vector calculation unit 111 may calculate a gravity vector indicating the magnitude and direction of gravity applied to the three-dimensional acceleration sensor 31 based on the measured value of gravitational acceleration.

Here, the rotation axis vector will be explained. The rotation axis vector is the so-called rotation vector of the joint axis, and is a vector perpendicular to the plane defined by the locus of the measured value of gravitational acceleration obtained when a given joint axis is driven (rotated) on a single axis. It is a line vector. The rotation axis vector calculation unit 111 outputs information on the calculated rotation axis vector to the correction parameter calculation unit 112.

The correction parameter calculation unit 112 calculates correction parameters for the joint axis specified by the operator based on the rotation axis vector of at least one joint axis obtained from the rotation axis vector calculation unit 111. The correction parameter calculation unit 112 outputs the calculated correction parameters for each joint axis to the display unit 14 for display. Further, the correction parameter calculation unit 112 transmits the calculated correction parameters for each joint axis to the robot control device R1, and causes the robot control device R1 to record them.

The measurement posture command unit 113 changes the posture (rotation angle) of the joint axis whose gravitational acceleration is currently being measured to a predetermined posture in order to obtain three or more different gravitational accelerations for one joint axis. Generate control commands. The measurement attitude command unit 113 transmits the generated control command to the robot control device R1. Note that the control command transmission process may be executed via the first communication unit 10 of the terminal device P1.

The first memory 12 includes, for example, a RAM (Random Access Memory) as a work memory used when executing the processing of the first processor 11, and a ROM (Random Access Memory) that stores a program that defines the processing of the first processor 11. Read Only Memory). Data generated or acquired by the first processor 11 is temporarily stored in the RAM. A program that defines the processing of the first processor 11 is written in the ROM. The first memory 12 records first posture data 121.

The first attitude data 121 includes information on the attitude (rotation angle) specified by the measurement attitude command unit 113 and three or more different measured values of gravitational acceleration measured by the three-dimensional acceleration sensor 31. This is the data. The first posture data 121 is recorded by the first processor 11 for each joint axis.

The input unit 13 is a user interface such as a touch panel, buttons, keyboard, mouse, etc., for example. The input unit 13 receives an operator's operation, converts it into an electrical signal (control command), and outputs it to the first processor 11 . Note that when configured using a touch panel, the input section 13 and the display section 14 may be configured integrally.

The display unit 14 is, for example, a display such as an LCD (Liquid Crystal Display) or an organic EL (Electroluminescence). The display unit 14 displays the calculation results of correction parameters for each joint axis.

The robot control device R1 controls each of the six joint axes of the robot M1 based on control commands transmitted from the terminal device P1. Robot control device R1 includes a second communication unit 20, a second processor 21, and a second memory 22.

The second communication unit 20 is connected to each of the terminal device P1 and the robot M1 so as to be able to transmit and receive data. The second communication unit 20 outputs control commands, correction parameters for each joint axis, etc. transmitted from the terminal device P1 to the second processor 21.

The second processor 21 is configured using, for example, a CPU or an FPGA, and performs various processing and control in cooperation with the second memory 22. Specifically, the second processor 21 refers to a program held in the second memory 22 and executes the program to realize the functions of each part. The second processor 21 drives and controls each joint axis of the robot M1 based on the control command transmitted from the terminal device P1, and uses correction parameters for each joint axis transmitted from the terminal device P1 and the current joint axis. The posture correction (adjustment) of each joint axis of the robot M1 is performed based on the angular difference with the posture of the axis.

The second memory 22 includes, for example, a RAM as a work memory used when executing the processing of the second processor 21, and a ROM that stores a program that defines the processing of the second processor 21. Data generated or acquired by the second processor 21 is temporarily stored in the RAM. A program that defines the processing of the second processor 21 is written in the ROM. The second memory 22 records second posture data 221.

The second posture data 221 is the posture of each of the six joint axes of the robot M1 (RT joint axis J1, UA joint axis J2, FA joint axis J3, RW joint axis J4, BW joint axis J5, TW joint axis J6). Record the (angle). When a correction parameter for correcting (adjusting) the posture of a joint axis is transmitted from the terminal device P1, the second posture data 221 is set to the posture (angle) indicated by the correction parameter acquired by the second processor 21. Can be rewritten.

The robot M1 is connected to the robot control device R1 so as to be able to transmit and receive data. In this embodiment, an example is shown in which the robot has six joint axes that can drive six arms, but it goes without saying that the number of joint axes is not limited to this.

The robot M1 has an RT joint axis J1 that is rotatable around the RT axis, a UA joint axis J2 that is rotatable around the UA axis, an FA joint axis J3 that is rotatable around the FA axis, and an FA joint axis J3 that is rotatable around the FA axis. It includes a rotatable RW joint axis J4, a BW joint axis J5 that is rotatable around the BW axis, and a TW joint axis J6 that is rotatable around the TW axis. A three-dimensional acceleration sensor 31 is attached to the arm tip 33 of the robot M1 by an operator.

The robot M1 includes a control section 32. The control unit 32 is controlled by a robot control device R1. The control unit 32 controls six joint axes (RT joint axis J1, UA joint axis J2, FA joint axis J3, RW joint axis J4, BW joint axis J5, TW) based on control commands transmitted from the robot control device R1. Drive control of each of the six arms is realized by driving a motor (not shown) provided on each of the joint shafts J6) to rotate the six joint shafts. Note that when measuring the gravitational acceleration of the joint axis, the control unit 32 drives (rotates) only the joint axis, which is the object of measurement of the gravitational acceleration, by a single axis.

The three-dimensional acceleration sensor 31, which is an example of an acceleration sensor, is attached to the arm tip 33 (an example of the tip) of the robot M1, and measures the gravitational acceleration of the joint axis based on the sensor coordinate system. Note that the sensor coordinate system here is a coordinate system set in the three-dimensional acceleration sensor 31, and is, for example, a coordinate system defined by each of the X-axis, Y-axis, and Z-axis shown in FIG. 3. The three-dimensional acceleration sensor 31 transmits information on the measured gravitational acceleration to the terminal device P1.

Next, referring to FIG. 3, the rotation axis vector of each joint axis will be explained. FIG. 3 is a diagram illustrating the six rotation axis vectors V _RT , V _UA , V _FA , V _RW , V _BW , V _TW of the robot and the coordinate system of the three-dimensional acceleration sensor 31 in the embodiment. Note that the sensor coordinate system of the three-dimensional acceleration sensor 31 shown in FIG. 3 is an example, and it goes without saying that the sensor coordinate system is not limited thereto.

The starting point of each of the rotation axis vectors V _RT , V _UA , V _FA , V _RW , V _BW , and V _TW calculated by the rotation axis vector calculation unit 111 coincides with the origin O of the sensor coordinates. As a result, the correction parameter calculation unit 112 performs a correction that allows the posture of the joint axis to be corrected (adjusted) based on a comparison between the rotation axis vector and the installation surface H0 (see FIG. 13), a comparison between a plurality of rotation axis vectors, etc. Parameters can be calculated.

Next, an example of the operation procedure of the robot system 100 will be described with reference to FIG. 4. FIG. 4 is a flowchart illustrating an example of the operation procedure of the robot system 100 according to the embodiment.

The terminal device P1 in the robot system 100 receives a selection (designation) operation of one or more joint axes by an operator, generates a control command requesting to start measuring the gravitational acceleration of the selected (designated) joint axes, The data is sent to the robot control device R1. The robot control device R1 adjusts the posture of the robot M1 to the measurement basic posture based on the control command transmitted from the terminal device P1. The terminal device P1 measures the gravitational acceleration of each joint axis by acquiring three or more gravitational accelerations transmitted from the three-dimensional acceleration sensor 31 for each joint axis (St11).

The terminal device P1 calculates the rotation axis vector of each joint axis using each of the three or more gravitational accelerations acquired for each joint axis (St12).

Based on the calculated rotational axis vector, the terminal device P1 calculates the angular difference between the joint axes, the angular difference between the joint axis and the installation surface H0 of the robot M1, or the angular difference between the joint axis and the gravity vector. The angular difference between the indicated direction of gravity and the like is calculated (St13). In addition, in step St13, the terminal device P1 receives the operator's selection of an object (joint axis, installation surface H0, direction of gravity, etc.) to be used for calculating the angular difference, and calculates the angular difference between any two selected objects. may be calculated. Thereby, the terminal device P1 can calculate the joint axis correction parameters desired by the operator.

Here, the angular difference calculated in the process of step St13 will be explained. When calculating the angular difference between two rotation axis vectors or between the rotation axis vector and the gravity vector, the terminal device P1 converts the interior angle between the two vectors into the angle between the two vectors. It may also be calculated as a difference. Alternatively, the terminal device P1 may calculate the orthogonal projection vectors of each of the two vectors, and calculate the interior angle of these two orthogonal projection vectors as the angular difference between the two vectors.

Based on the calculated angular difference, the terminal device P1 calculates a correction parameter (angle) of the joint axis that is the target of posture correction (adjustment) (St14).

The terminal device P1 associates the calculated correction parameters for each joint axis with a control command for rewriting the existing posture data of the robot M1 to new posture data based on the correction parameters, and sends them to the robot control device R1. , rewriting the second posture data 221 (St15).

The terminal device P1 displays the calculation results of the correction parameters for each joint axis on the display unit 14, and notifies the operator of the calculation results of the correction parameters calculated for each joint axis (St16).

As described above, the robot system 100 according to the embodiment can more easily calculate the correction parameters for the posture of the joint axes of the robot M1. Furthermore, by displaying the calculation results of the correction parameters on the display unit 14, the robot system 100 can more effectively support the posture correction (adjustment) work of the robot M1 performed by the worker.

Note that the posture correction (adjustment) work of the robot M1 may be performed by the robot control device R1. In such a case, the robot control device R1 corrects the posture of each joint axis based on the angle (posture) difference between the second posture data 221 before rewriting and the correction parameter transmitted from the terminal device P1. adjustment).

Next, step St11 (method for measuring gravitational acceleration) shown in FIG. 4 will be described with reference to FIGS. 5 and 6, respectively. FIG. 5 is a flowchart illustrating an example of a procedure for measuring gravitational acceleration of the robot system 100 according to the embodiment. FIG. 6 is a flowchart illustrating an example of a procedure for measuring gravitational acceleration of the robot system 100 according to the embodiment. In addition, in the explanation of FIGS. 5 and 6, in order to make the explanation easier to understand, as an example, the gravitational acceleration is measured when the posture (rotation angle) of the joint axis indicated by "joint axis A" is changed. I will explain about it.

The operator attaches the three-dimensional acceleration sensor 31 to a predetermined position on the arm tip 33 of the robot M1 (St111). Note that if the three-dimensional acceleration sensor 31 is always attached, the process of step St111 may be omitted.

The terminal device P1 accepts an operation by the operator to select (designate) any one of the joint axes A whose gravitational acceleration has not yet been measured as the target for measuring gravitational acceleration (St112). The terminal device P1 generates a control command requesting the start of measurement of the gravitational acceleration corresponding to the change in posture of the selected joint axis A, and transmits it to the robot control device R1.

Note that the number of joint axes selected (designated) in step St112 may be plural. When the terminal device P1 receives an operation for selecting (designating) a plurality of joint axes whose gravitational acceleration is to be measured, the terminal device P1 determines whether the gravitational acceleration has not been measured among each of the plurality of selected (designated) joint axes. , and any one joint axis A is selected.

Further, in step St112, the terminal device P1 performs an operation for selecting (designating) an adjustment purpose or a detection purpose regarding the posture of the joint axes of the robot M1, such as adjusting the inclination of the robot M1 with respect to the installation surface, adjusting the origin, and detecting axis deviation. You may accept it. In such a case, the terminal device P1 records information on one or more joint axes whose gravitational acceleration is to be measured in the first memory 12 for each adjustment purpose or detection purpose. The terminal device P1 refers to the first memory 12, and based on the information of the joint axes associated with the adjustment purpose or the detection purpose selected (designated) by the operator's operation, the terminal device P1 determines at least one target for measuring the gravitational acceleration. Determine one joint axis.

Based on the control command transmitted from the terminal device P1, the robot control device R1 controls the motors capable of driving each joint axis of the robot M1 so as to take the basic measurement posture, and adjusts the posture of the robot M1 ( St13). When the adjustment of the robot M1 to the measurement basic posture is completed, the robot control device R1 generates a control command (electrical signal) to notify the completion of the adjustment to the measurement basic posture, and transmits it to the terminal device P1.

Note that the measurement basic posture here is a posture (rotation angle) that is adjusted as a basic posture when measuring gravitational acceleration, and information on the posture (rotation angle) is recorded in the first memory 12 for each joint axis. be done. The basic measurement postures are, for example, RT joint axis J1 = 0 (zero) degrees, UA joint axis J2 = -50 degrees, FA joint axis J3 = -50 degrees, RW joint axis J4 = 0 (zero) degrees, BW joint axis J5=-10°, TW joint axis J6=0 (zero)°. Note that the basic measurement posture described above is just an example, and it goes without saying that the present invention is not limited to this.

The terminal device P1 determines the number of measurements i (i: 0 or more) of the gravitational acceleration corresponding to the posture change of the joint axis A, based on the control command sent from the robot control device R1 to notify the completion of adjustment to the measurement basic posture. Integer) is set to i=1 (St114). The terminal device P1 acquires (receives) the current posture (rotation angle) information of the joint axis A from the robot control device R1, and acquires the gravitational acceleration from the three-dimensional acceleration sensor 31 attached to the arm tip 33 of the robot M1. (Receive) (St115).

The terminal device P1 associates the posture (rotation angle) information of the joint axis A with the measured values of gravitational acceleration (x _i , y _i , z _i ) based on the acquired measured value of gravitational acceleration, and determines the joint axis. It is recorded in the first memory 12 as posture data of A (St116).

The terminal device P1 determines whether the number of times i of measuring the gravitational acceleration corresponding to the posture change of the joint axis A is equal to or greater than a predetermined number m (m: an integer of 3 or more) (St117). Note that the predetermined number of times m may be set to an arbitrary number of times by the operator.

In the process of step St117, if the terminal device P1 determines that the number of times i of measuring the gravitational acceleration corresponding to the posture change of the joint axis A is equal to or more than the predetermined number m (i≧m) (St117, YES), all It is determined whether the measurement of the gravitational acceleration corresponding to the posture change of the joint axis has been completed (St118). Note that all joint axes herein refer to all joint axes selected (designated) in the process of step St112.

On the other hand, in the process of step St117, if the terminal device P1 determines that the number of measurements of the gravitational acceleration corresponding to the posture change of the joint axis A is not equal to or greater than the predetermined number of times m (i<m) (St117, NO), the terminal device P1 A control command for changing the attitude (rotation angle) of axis A is generated and transmitted to robot control device R1.

Based on the control command transmitted from the terminal device P1, the robot control device R1 drives (rotates) a single joint axis A among the six joint axes of the robot M1, and changes the posture of the joint axis A. The posture is changed (St119). When the posture change of the joint axis A is completed, the robot control device R1 associates the posture (rotation angle) information of the joint axis A after the change with a control command that notifies the completion of the posture change and sends it to the terminal device P1. do.

Note that the change to a different posture may be realized, for example, by rotating only the joint axis A (that is, a single axis) by a predetermined rotation angle (for example, 15 degrees, 30 degrees, 60 degrees, etc.). , may be realized by rotating only the joint axis A through three or more preset rotation angles (for example, 0 (zero) degrees, 120 degrees, 270 degrees, etc.).

The terminal device P1 acquires the changed posture (rotation angle) information of the joint axis A and the control command transmitted from the robot control device R1. Based on the control command, the terminal device P1 increments the number of gravitational acceleration measurements i (i=i+1) (St120), and measures the gravitational acceleration from the three-dimensional acceleration sensor 31 attached to the arm tip 33 of the robot M1. The value is acquired (received) (St115).

If the terminal device P1 determines in the process of step St118 that the measurement of the gravitational acceleration corresponding to the posture change of all joint axes has been completed (St118, YES), the terminal device P1 generates a notification that the measurement of the gravitational acceleration has been completed. and is displayed on the display unit 14. The operator completes the gravitational acceleration measurement work by removing the three-dimensional acceleration sensor 31 from the arm tip 33 of the robot M1 (St121). Note that the process of step St121 may be omitted if there is no need to remove the three-dimensional acceleration sensor 31.

On the other hand, if the terminal device P1 determines in the process of step St118 that the measurement of the gravitational acceleration corresponding to the posture change of all joint axes is not completed (St118, NO), the terminal device P1 determines that the gravitational acceleration is to be measured by the worker. , a selection (designation) operation for any joint axis A whose gravitational acceleration has not been measured is accepted (St112). Note that the terminal device P1 may automatically select any one joint axis for which the gravitational acceleration is not measured, without any selection operation by the operator.

Next, with reference to FIG. 7, the process of step St12 shown in FIG. 4 (rotation axis vector calculation process) will be described. FIG. 7 is a flowchart illustrating an example of a procedure for calculating the rotation axis vector of the terminal device P1 in the embodiment. In addition, in the explanation of FIG. 7, in order to make the explanation easier to understand, an example will be explained in which the gravitational acceleration is measured when the posture (rotation angle) of the joint axis indicated by "joint axis A" is changed. .

The terminal device P1 determines the joint axis A for calculating the rotation axis vector (St211). Note that the process for determining the joint axis A may be performed by the operator. In such a case, the terminal device P1 determines the joint axis A selected by the operator as the joint axis for which the rotation axis vector is calculated.

The terminal device P1 refers to the first memory 12 and acquires posture data corresponding to the joint axis A (St212). The terminal device P1 calculates the difference value of each of the m measured values of gravitational acceleration measured at each posture (rotation angle) (St213), and determines whether each calculated difference value is greater than or equal to the threshold ThA. is determined (St214). Note that the threshold ThA is a value indicating measurement noise (measurement error) of the three-dimensional acceleration sensor, and may be set to an arbitrary value by the operator.

If the terminal device P1 determines in the process of step St214 that the calculated difference value is greater than or equal to the threshold ThA (St214, YES), the terminal device P1 adds measurement noise of the three-dimensional acceleration sensor to each of the m gravitational acceleration measurement values. It is determined that there is a significant difference. The terminal device P1 calculates m measured values of gravitational acceleration based on each of the m measured values of gravitational acceleration (x _i , y _i , z _i ), ..., (x _m , y _m , z _m ). A plane obtained by each plot (for example, the plane P _TW shown in FIG. 8) is estimated (St215). Note that the plane may be estimated using SVD (Singular Value Decomposition), or other plane estimation methods may be used.

On the other hand, if the terminal device P1 determines in the process of step St214 that the calculated difference value is not equal to or greater than the threshold ThA (St214, NO), the terminal device P1 converts the gravity vector indicated by the measured value of gravitational acceleration into the rotational axis vector of the joint axis A. (St216). Note that the process of step St216 will be explained using a specific example in the explanation of FIG. 10, which will be described later.

The terminal device P1 projects each of the m measured values of gravitational acceleration onto the estimated plane. The terminal device P1 draws a circle (for example, 8) is estimated ( _St217 ). The terminal device P1 determines whether the radius of the estimated circle is less than or equal to the threshold ThB (St218).

In the process of step St218, if the terminal device P1 determines that the radius of the estimated circle is equal to or less than the threshold ThB (St218, YES), the terminal device P1 determines the center coordinates of the estimated circle (for example, the center coordinates CO shown in FIG. 8). ) is determined as the rotation axis vector of the joint axis A (St219). Note that the process of step St219 will be explained using a specific example in the explanation of FIG. 11, which will be described later.

On the other hand, if the terminal device P1 determines in the process of step St218 that the radius of the estimated circle is not equal to or less than the threshold ThB (St218, NO), the terminal device P1 converts the normal vector to the estimated plane into the rotation axis vector of the joint axis A. (St220). Note that the process of step St220 will be explained using a specific example in the explanation of FIG. 12, which will be described later.

The terminal device P1 determines the sign (that is, the direction) of the set rotation axis vector based on the rotation direction in which the joint axis A is rotated in the forward direction (St221).

For example, in each of Step St216, Step St219, and Step St220, the terminal device P1 determines the direction along the forward rotation direction of the motor that drives the joint axis A as the direction of the rotation axis vector.

For example, the terminal device P1 calculates the angular difference between the determined direction of the rotation axis vector and the direction of the rotation axis vector calculated based on the measured value of gravitational acceleration. If the calculated angular difference is an acute angle, the terminal device P1 determines the direction of the rotation axis vector calculated based on the measured value of gravitational acceleration, and if the calculated angular difference is an obtuse angle, the terminal device P1 determines the direction of the rotation axis vector based on the measured value of gravitational acceleration. The direction of the rotation axis vector calculated based on the measured value may be reversed.

The terminal device P1 determines whether calculation of the rotational axis vectors of all the joint axes measured in the process of step St11 has been completed (St222).

If the terminal device P1 determines in the process of step St222 that the calculation of the rotational axis vectors of all the joint axes has been completed (St222, YES), the terminal device P1 ends the rotational axis vector calculation process.

On the other hand, if the terminal device P1 determines in the process of step St222 that calculation of the rotational axis vectors of all the joint axes has not been completed (St222, NO), the terminal device P1 returns to the process of step St211 and Select one of the joint axes for which has not yet been calculated (St211).

The process of step St215 (plane estimation process) and the process of step St217 (circle estimation process) shown in FIG. 7 will be described with reference to FIGS. 8 and 9, respectively. FIG. 8 is a diagram illustrating an example of the plane P _TW and the circle C _TW . FIG. 9 is a diagram illustrating an example of a circle C _TW estimation processing procedure.

In addition, in FIG. 8, as an example, the plane P TW and the circle C _TW estimated based on each of m measured values of gravitational acceleration obtained when changing the posture (rotation angle) of the TW joint axis _J6 are shown. Each is shown below. In addition, in FIG. 9, in order to make the explanation of the estimation processing procedure for each of the plane P _TW and the circle C _TW easier to understand, an example different from the positional relationship between the sensor coordinate system and the plane P _TW and the circle C _TW shown in FIG. 8 is shown. shows.

The X-axis, Y-axis, and Z-axis shown in FIGS. 8 and 9 each indicate a sensor coordinate system set in the three-dimensional acceleration sensor 31.

The plane P _TW is a plane estimated by the process of step St215. The terminal device P1 uses each of the m measured values of gravitational acceleration (x _i , y _i , z _i ), ..., (x _m , y _m , z _m ) to calculate (Equation 1) which indicates a plane. By calculating each of the coefficients a, b, c, and d, the estimation process of the plane P _TW is executed.

The circle C _TW is a circle estimated by the process of step St217. Hereinafter, with reference to FIG. 9, the circle C _TW estimation process will be specifically described.

In the sensor coordinate system, the terminal device P1 calculates a unit normal vector of the plane P _TW estimated using (Equation 1), and converts the calculated unit normal vector of the plane P _TW into a unit vector in the Z-axis direction. A rotation matrix R _TW is calculated to match (St217-1). Note that any known method may be used to calculate the rotation matrix R _TW ; for example, Rodriguez's rotation formula may be used.

As shown in (Equation 2), _the terminal device P1 calculates each of the m measured values of gravitational acceleration (x _i , y _i , z _i ), ..., (x _m , y _m , z _m ), the plane P _TW is rotated (St217-2). Note that the plane P _TW ′ is the plane P _TW after being rotated using the rotation matrix R _TW . The transformation values (x _i ′, y _i ′, z _i ′), ..., (x _m ′, y _{m ′} , z _m ′) are the m gravitational forces after being rotated using the rotation matrix R _TW . Each of the measured values of acceleration.

The terminal device P1 calculates the coordinates (x i ′) on the XY plane among the m converted values (x _i ′, y _i ′, z _{i ′} ), ..., (x _m ′, y _m ′, z _m _′ ) , y _i ′), ..., (x _m ′, y _m ′), the circle C _TW ′ is estimated (St217-3). The terminal device P1 calculates the center coordinates CO' (c _x ', c _y ') of the estimated circle C _TW ' and the radius r of the circle C _{T W} ' (St217-3). Note that the estimation of the circle C _{TW ′} is performed using any known method such as the method of least squares, for example.

The terminal device P1 calculates the distance D between the origin of the sensor coordinate system and the plane P _TW ′ as the Z coordinate in the center coordinate CO′ (c _x ′, c _y ′) of the circle C _TW ′ (St217 -4).

The terminal device P1 calculates an inverse matrix R _TW ^-1 of the rotation matrix R _TW . The terminal device P1 uses the calculated inverse matrix R _TW ^-1 to calculate the center coordinates CO (c _x , c _y , c _z ) of the circle C _TW in the sensor coordinate system, as shown in (Equation 3). (St217-5).

As described above, the terminal device P1 can estimate the center coordinates CO (c _x , c _y , _cz ) of the circle C _TW .

With reference to FIG. 10, the process of step St216 (rotation axis vector determination process) shown in FIG. 7 will be described. FIG. 10 is a diagram illustrating example 1 of setting the rotation axis vector. In addition, in FIG. 10, as an example, an example of a process for determining the rotation axis vector V _RT when the object of measurement of gravitational acceleration is the RT joint axis J1 will be described.

Setting example 1 of the rotation axis vector is a gravity vector G indicated by the rotation axis of the joint axis and the direction of gravity measured by the three-dimensional acceleration sensor 31, such as the RT joint axis J1 when the robot M1 is installed on a horizontal plane. This is an example of a process for determining the rotation axis vector in a case where the rotation axis vector and _RT match.

In such a case, each difference value of the m measured values of gravitational acceleration is no more than the threshold ThA. Therefore, in the process of step St214, the terminal device P1 determines that the calculated difference value is not greater than or equal to the threshold ThA, and proceeds to the process of step St216, changing the gravity vector G _RT to the rotation axis vector V of the RT joint axis J1. Decided to _RT .

The process of step St219 (rotation axis vector determination process) shown in FIG. 7 will be described with reference to FIG. 11. FIG. 11 is a diagram illustrating a second example of setting the rotation axis vector. In addition, in FIG. 11, as an example, an example of a process for determining the rotation axis vector V _TW in a case where the gravitational acceleration measurement target is the TW joint axis J6 will be described.

Setting example 2 of the rotation axis vector is based on the angle (for example, the angle difference) between the rotation axis of the joint axis and the direction of gravity measured by the three-dimensional acceleration sensor 31, such as the TW joint axis J6 shown in FIG. This is an example of a rotation axis vector determination process when θ _TW ) is small.

In such a case, the circle C _TW estimated by each of the m gravitational acceleration measurements (x _i , y _i ), ..., (x _m , y _m ) is at a position far from the origin of the sensor coordinate system ( That is, the distance D shown in FIG. 9 is large) has a radius r that is less than or equal to the threshold ThB.

In addition, in such a case, as shown in FIG. 11, when a measurement error ER11 exists, the rotation axis vector V _TW based on the estimated center coordinates CO _TW of the circle C _TW is set as the rotation axis vector of the TW joint axis J6. Measurement error ER12 from the ideal rotation axis vector V' _TW when determined, and the ideal rotation axis vector when the normal vector of the estimated plane P _TW is determined as the rotation axis vector of the TW joint axis J6. When comparing the measurement error ER13 with V' _TW , the measurement error ER12 is smaller. Note that the center coordinates CO' _TW shown in FIG. 11 are the center coordinates of a circle estimated based on ideal measured values. The plane P′ _TW is a plane estimated based on ideal measurement results. Moreover, "ideal" here refers to an ideal measurement result without measurement error of the three-dimensional acceleration sensor 31.

Therefore, the terminal device P1 passes through the origin O of the sensor coordinate system and the center coordinates CO _TW of the circle C _TW estimated through the process of Step St217, rather than the normal vector of the plane estimated through the process of Step St215. The rotational axis vector V _TW is determined as the rotational axis vector of the TW joint axis J6.

Thereby, the terminal device P1 determines the value obtained by the three-dimensional acceleration sensor 31 based on the magnitude relationship between the value of the threshold ThB set corresponding to the magnitude of the measurement error of the three-dimensional acceleration sensor 31 and the radius of the circle. It is possible to determine a rotation axis vector that reduces the error in measuring the posture of the joint axis, that is, increases the accuracy of measuring the posture of the joint axis.

Step St220 (rotation axis vector determination process) shown in FIG. 7 will be described with reference to FIG. 12. FIG. 12 is a diagram illustrating a third example of setting the rotation axis vector. In addition, in FIG. 12, as an example, an example of a process for determining the rotation axis vector _VUA when the object of measurement of gravitational acceleration is the UA rotation axis will be described.

Example 3 of setting the rotational axis vector is when the rotational axis of the joint axis and the direction of gravity measured by the three-dimensional acceleration sensor 31 are at right angles or at right angles, such as UA joint axis J2 and FA joint axis J3 shown in FIG. This is an example of a process for determining a rotation axis vector when the angles are close to each other.

In such a case, the circle C _UA estimated by each of the m gravitational acceleration measurements (x _i , y _i ), ..., (x _m , y _m ) is located near the origin O of the sensor coordinate system. , has a radius r that is greater than or equal to the threshold ThB. Note that the radius of the estimated circle _CUA is maximum when the angle between the rotation axis of the UA joint axis J2 and the gravity vector _GUA indicating the direction of gravity measured by the three-dimensional acceleration sensor 31 is a right angle. Become.

Furthermore, in such a case, as shown in FIG. 12, if the measured value of the three-dimensional acceleration sensor 31 includes a measurement error ER23, the normal vector of the estimated plane _PUA is converted into the rotational axis vector V of the UA joint axis J2. The measurement error ER22 when determined as _UA is more similar to the ideal rotational axis vector V' _UA than the measurement error ER21 when determined as the rotational axis vector based on the estimated center coordinates _COUA of the circle _CUA . measurement error becomes smaller. Note that the center coordinates CO' _UA shown in FIG. 12 are the center coordinates of a circle estimated based on ideal measured values. The plane P' _UA is a plane estimated based on ideal measurement results.

Therefore, the terminal device P1 uses the rotation axis vector estimated by the process of step St215, not the rotation axis vector passing through the center coordinates of the circle _CTW estimated by the process of step St217 and the origin O (not shown) of the sensor coordinate system. The normal vector of the plane (not shown) is determined as the rotation axis vector _VUA of the UA joint axis J2.

Next, with reference to FIG. 13, a method of utilizing the rotation axis vector will be described. FIG. 13 is a diagram illustrating an example of detecting the inclination of the installation surface H1 of the robot M1.

The terminal device P1 determines whether the robot M1 can move based on the angle (=angular difference θ _RT ) between the determined rotational axis vector V _RT and the gravity vector G _RT based on the measured value of the gravitational acceleration by the three-dimensional acceleration sensor 31. The inclination (=angular difference θ _RT ) of the installed installation surface H1 can be calculated. The terminal device P1 calculates correction parameters for each joint axis based on the calculated angular difference θ _RT . This allows the operator to correct the inclination of the robot M1 with respect to the installation surface H1.

Furthermore, the terminal device P1 may calculate a gravity compensation parameter for motor control of each joint axis based on the calculated inclination of the installation surface H1 (=angular difference θ _RT ), and may transmit it to the robot control device R1. .

Next, with reference to FIG. 14, a method of utilizing the rotation axis vector will be described. FIG. 14 is a diagram illustrating an example of detecting axis deviation of joint axes. Note that here, detection of the axis deviation of the FA joint axis J3 when no axis deviation has occurred in the UA joint axis J2 will be described.

In the robot M1 shown in FIG. 14, a component M11 that rotates around the FA axis is assembled in a mounting posture PT1 that differs from the normal mounting posture PT0 due to foreign matter that got into it during assembly.

The terminal device P1 calculates an angular difference θ _FA between the rotation axis vector V _FA of the FA joint axis J3 and the rotation axis vector V _UA of the UA joint axis J2, which are in a parallel relationship in a state where no axis deviation occurs. Based on the calculated angular difference θ _FA , the terminal device P1 determines whether an axis misalignment has occurred in the FA joint axis J3 or the UA joint axis J2, and determines the sign (direction) of the angular difference θ _FA . Based on this, the direction of axis deviation is determined. Note that the terminal device P1 may compare the calculated angular difference θ _FA with a predetermined threshold value and determine whether an axis deviation has occurred in the FA joint axis J3 or the UA joint axis J2.

Thereby, the terminal device P1 can detect abnormalities in the component M11 itself (for example, deterioration, defects, etc. of the component M11), abnormalities in the assembly of the component M11, etc., based on the calculated angular difference θ _FA .

Note that the terminal device P1 determines whether the calculated value is not due to an abnormality in the component M11 itself (for example, deterioration or defect in the component M11) or an abnormality in the assembly of the component M11, but simply when an axis misalignment of the FA joint axis has occurred. Based on the angle difference θ _FA , a correction parameter for correcting the posture inclination of the FA joint axis can be calculated.

Next, a method of utilizing the rotation axis vector will be described with reference to FIGS. 15 and 16, respectively. FIG. 15 is a diagram illustrating an example of adjusting the origin of the wrist axes (RW joint axis J4, BW joint axis J5, TW joint axis J6). FIG. 16 is a diagram illustrating an example of the angular differences Φ _RW and Φ _TW . Note that the wrist axis here indicates each of the three joint axes near the arm tip 33, which are the RW joint axis J4, the BW joint axis J5, and the TW joint axis J6.

In addition, in the origin adjustment example shown in FIG. 15, an example in which the basic measurement posture of the robot M1 is set to have an angular difference of 10 degrees between the TW axis and the RW axis will be specifically explained.

When the terminal device P1 changes the respective postures (rotation angles) of the RW joint axis J4, TW joint axis J6, and BW joint axis J5 in the order of RW joint axis J4, TW joint axis J6, and BW joint axis J5, Measure the resulting gravitational acceleration.

The terminal device P1 determines the planes P RW , P TW , and P BW corresponding to each joint axis based on the measured gravitational acceleration values of the _RW joint axis J4, _TW joint axis J6, and _BW joint axis J5. and circles C _RW (not shown), C _TW (not shown), and C _BW , respectively. The terminal device P1 corresponds to each joint axis based on each of the estimated planes P _RW , P _TW , and P _BW and circles C _RW (not shown), C _TW (not shown), and C _BW . Each of the rotation axis vectors V _RW , V _TW , and V _BW is determined.

The terminal device P1 calculates the angle difference θ BW between the rotation axis vector V _RW of the RW joint axis J4 and the rotation axis vector V _TW of the TW joint axis J6 when rotating the rotation axis vector V _BW of the _BW joint axis J5. The angular differences Φ _RW and Φ _TW between the rotation axis vector V _BW and the inclination (posture) direction of the rotation axis vector V BW are calculated. Note that the angle difference θ _BW calculated here is a value that changes depending on the operating angle of the BW joint axis J5. That is, the terminal device P1 calculates the correction parameters so that the angular difference θ _BW matches the measurement basic posture, thereby making it possible to execute the origin adjustment of the robot M1.

For example, in the example shown in FIG. 15, the terminal device P1 calculates the angle difference = 0 between the calculated angle difference θ _BW = 10.5° and the angle difference = 10° set as the measurement basic posture of the robot M1. .5°, a correction parameter for executing the origin adjustment of the BW joint axis J5 is calculated. The terminal device P1 displays the calculated correction parameters on the display unit 14 and transmits them to the robot control device R1. This allows the operator to adjust the origin of the BW joint axis J5 with higher precision.

Further, each of the angular differences Φ _RW and Φ _TW is an angle that does not depend on the operating angle of the robot M1. Therefore, the terminal device P1 can detect assembly abnormalities of the wrist axes ( _RW joint axis J4, BW joint axis J5, TW joint axis J6) based on each of the calculated angular differences Φ RW and Φ _TW .

As described above, the robot system 100 according to the embodiment has a plurality of joint axes (one example of a motion axis, for example, RT joint axis J1, UA joint axis J2, FA joint axis J3, RW joint axis J4, BW joint axis A robot M1 having an axis J5, a TW joint axis J6), a robot control device R1 that operates each of a plurality of joint axes to adjust the posture of the joint axes, and an arm tip 33 of the robot M1 (an example of a tip ), a three-dimensional acceleration sensor 31 (an example of an acceleration sensor) that measures the gravitational acceleration at the arm tip 33, a terminal device P1 capable of communicating between the three-dimensional acceleration sensor 31 and the robot control device R1, Equipped with The robot control device R1 moves a first joint axis among the plurality of joint axes to at least three different postures. The terminal device P1 stores three or more first gravitational acceleration data detected by the three-dimensional acceleration sensor 31 in each of three or more postures, and based on the three or more stored first gravitational acceleration data. , calculates a first rotational axis vector of the first joint axis in a three-dimensional space, and calculates a correction parameter for correcting the posture deviation of the robot M1 based on the calculated first rotational axis vector.

Thereby, the robot system 100 according to the embodiment can more accurately calculate correction parameters that can correct the posture deviation of each joint axis. Therefore, the operator can more easily correct the posture deviation of the robot M1 based on the calculated correction parameters.

Further, the terminal device P1 in the robot system 100 according to the embodiment calculates the first rotation axis vector and the gravity vector along the gravity direction measured by the three-dimensional acceleration sensor 31, and calculates the first rotation axis vector, A correction parameter is calculated based on the angular difference between the gravity vector and the gravity vector. Thereby, the robot system 100 according to the embodiment can calculate correction parameters that can perform more accurate tilt correction on the installation surface H1 of the robot M1.

Further, the robot control device R1 in the robot system 100 according to the embodiment operates the posture of a second joint axis that is different from the first joint axis among the plurality of joint axes to at least three or more different postures. let The terminal device P1 stores three or more second gravitational acceleration data detected by the three-dimensional acceleration sensor 31 in each of three or more postures of the second joint axis, and stores the three or more second gravitational acceleration data detected by the three-dimensional acceleration sensor 31 in each of the three or more postures of the second joint axis. A second rotational axis vector of the second joint axis in three-dimensional space is calculated based on the acceleration data, and a correction parameter is calculated based on the angular difference between the calculated first rotational axis vector and the second rotational axis vector. do. As a result, the robot system 100 according to the embodiment can adjust (correct) the joint axes of the robot M1 with higher precision based on the calculated angular difference (for example, the angular difference θ _FA shown in FIG. 14). It is possible to calculate correction parameters for executing.

Further, the robot control device R1 in the robot system 100 according to the embodiment can change the posture of a third joint axis that is different from the first joint axis and the second joint axis among the plurality of joint axes into at least three different postures. It works in the above posture. The terminal device P1 stores three or more third gravitational acceleration data detected by the three-dimensional acceleration sensor 31 in each of three or more postures of the third joint axis, and stores the three or more third gravitational acceleration data detected by the three-dimensional acceleration sensor 31 in each of the three or more postures of the third joint axis. A third rotational axis vector of the third joint axis in three-dimensional space is calculated based on the acceleration data, and an angular difference between the calculated first rotational axis vector, second rotational axis vector, and third rotational axis vector is calculated. Calculate correction parameters based on Thereby, the robot system 100 according to the embodiment can calculate correction parameters for performing more accurate origin adjustment of the joint axes.

Although various embodiments have been described above with reference to the drawings, it goes without saying that the present disclosure is not limited to such examples. It is clear that those skilled in the art can come up with various changes, modifications, substitutions, additions, deletions, and equivalents within the scope of the claims, and It is understood that it naturally falls within the technical scope of the present disclosure. Further, each of the constituent elements in the various embodiments described above may be arbitrarily combined without departing from the spirit of the invention.

The present disclosure is useful as a robot system that adjusts the posture of each joint of a robot with higher precision.

10 First communication section 20 Second communication section 11 First processor 21 Second processor 12 First memory 22 Second memory 13 Input section 14 Display section 31 Three-dimensional acceleration sensor 32 Control section 33 Arm tip section 100 Robot system 111 Rotation axis vector calculation section 112 Correction parameter calculation section 113 Measurement posture command section 121 First posture data 221 Second posture data J1 RT joint axis J2 UA joint axis J3 FA joint axis J4 RW joint axis J5 BW joint Axis J6 TW joint axis M1 Robot P1 Terminal device R1 Robot control device

Claims

A robot with multiple motion axes,
a robot control device that operates each of the plurality of motion axes to adjust the posture of the motion axes;
an acceleration sensor that is provided at the tip of the robot and measures gravitational acceleration at the tip;
A robot system comprising: a terminal device capable of communicating between the acceleration sensor and the robot control device;
The robot control device includes:
moving the posture of any one of the first motion axes among the plurality of motion axes to at least three different postures;
The terminal device is
storing three or more first gravitational acceleration data detected by the acceleration sensor in each of the three or more postures;
calculating a first rotational axis vector of the first motion axis in three-dimensional space based on the three or more stored first gravitational acceleration data;
calculating a correction parameter for correcting the posture deviation of the robot based on the calculated first rotation axis vector;
robot system.
The terminal device is
Calculating the first rotation axis vector and a gravity vector along the gravity direction measured by the acceleration sensor,
calculating a correction parameter based on the angular difference between the first rotation axis vector and the gravity vector;
The robot system according to claim 1.
The robot control device includes:
operating a second movement axis different from the first movement axis among each of the plurality of movement axes into at least three or more different postures;
The terminal device is
storing three or more second gravitational acceleration data detected by the acceleration sensor in each of the three or more postures of the second motion axis;
calculating a second rotational axis vector of the second motion axis in the three-dimensional space based on the three or more stored second gravitational acceleration data;
calculating a correction parameter based on the angular difference between the calculated first rotation axis vector and the second rotation axis vector;
The robot system according to claim 1.
The robot control device includes:
operating a third operating axis different from the first operating axis and the second operating axis among each of the plurality of operating axes to at least three or more different postures;
The terminal device is
storing three or more third gravitational acceleration data detected by the acceleration sensor in each of the three or more postures of the third motion axis;
calculating a third rotational axis vector of the third motion axis in the three-dimensional space based on the three or more stored third gravitational acceleration data;
calculating a correction parameter based on the angular difference between the calculated first rotation axis vector, the second rotation axis vector, and the third rotation axis vector;
The robot system according to claim 3.
A robot with multiple motion axes,
a robot control device that operates two or more of the plurality of motion axes and adjusts the posture of the two or more operated motion axes;
an acceleration sensor that is provided at the tip of the robot and measures gravitational acceleration at the tip;
A robot system comprising: a terminal device capable of communicating between the acceleration sensor and the robot control device;
The robot control device includes:
moving the postures of the respective motion axes of the two or more operated motion axes to at least three or more different postures;
The terminal device is
storing three or more first gravitational acceleration data detected by the acceleration sensor in each of the three or more postures;
Based on the three or more stored first gravitational acceleration data, calculate a rotational axis vector of each of the two or more operated axes in three-dimensional space;
calculating a correction parameter for correcting the posture deviation of the robot based on each of the calculated rotational axis vectors;
robot system.