Robot system comprising calibration jig, and control method therefor

Abstract

A robot system (1, 2, 3, 4), according to one embodiment, may comprise: a main body (11, 11'); an end effector (122) connected to the main body (11, 11') by means of a plurality of joints (121); a calibration tool (123) installed on the end effector (122) and having at least a portion thereof formed in a spherical shape; and a calibration jig (14, 14a, 14b, 14', 24, 34, 44) disposed in a position in which the calibration tool (123) may be in contact, and comprising a plurality of reference areas (a1, a2, a3, a4) in which the calibration tool (123) may be in three-point contact.

Description

Robot system including a calibration jig and a control method thereof

[0001] The following disclosure relates to a robot system including a calibration jig and a method for controlling the same.

[0002] Recently, robots are being widely used in industrial settings to improve productivity, reduce manpower, and enhance quality, and their adoption is accelerating. In particular, as industrial processes become more complex and diverse, tools with high degrees of freedom may be required. Therefore, robots (or equipment) can be attached and used in place of robot tools. However, as the robot's degrees of freedom increase, the accumulated errors during operation may also increase. As accumulated errors rise, it may become difficult to ensure high robot precision. Robot precision can include repeatability and / or absolute precision. Machining or assembly errors arising during the manufacturing or attachment of robots or tools can lower the robot's absolute precision. To address this, a robot calibration process may be necessary.

[0003] The aforementioned related art is possessed or acquired during the process of deriving the present disclosure and cannot be considered prior art disclosed to the general public prior to the filing of the present disclosure.

[0004] A robot system (1; 2; 3; 4) according to one embodiment may include a main body (11; 11'), an end effector (122) connected to the main body (11; 11') by a plurality of joints (121), a calibration tool (123) installed on the end effector (122) and having at least a portion formed in a spherical shape, and a calibration jig (14; 14a; 14b; 14'; 24; 34; 44) disposed at a position where the calibration tool (123) can contact it, and including a plurality of reference areas (a1, a2, a3, a4) where the calibration tool (123) can make three-point contact.

[0005] A robot system (1; 2; 3; 4) according to one embodiment may include a main body (11; 11'), an end effector (122) connected to the main body (11; 11') by a plurality of joints (121), a calibration tool (123) installed on the end effector (122) and having at least a portion formed in a spherical shape, and a calibration jig (14; 14a; 14b; 14'; 24; 34; 44) installed on the main body (11; 11') and comprising a plurality of reference areas (a1, a2, a3, a4) to which the calibration tool (123) can make three-point contact, and at least one guide groove (141; 241; 341; 441) interconnecting the plurality of reference areas (a1, a2, a3, a4).

[0006] According to one embodiment, a calibration method for a robot system (1; 2; 3; 4) using a calibration jig (14; 14a; 14b; 14'; 24; 34; 44) comprising a plurality of reference regions (a1, a2, a3, a4) that can be three-point contacted by a calibration tool (123) comprises, with the calibration tool (123) mounted on the end of a robot arm (12), driving each joint (121) of the robot arm (12) with a design-based joint value determined through a design-based equation of motion so that the calibration tool (123) approaches a first reference region (a1) among the plurality of reference regions (a1, a2, a3, a4), and driving the robot arm (12) until the calibration tool (123) makes three-point contact with the first reference region (a1), 923), the calibration tool (123) may include an operation (924) of storing the actual joint value of each joint (121) of the robot arm (12) while the calibration tool (123) is in three-point contact with the first reference area (a1), and an operation (927) of adjusting the parameter for the position of the equation of motion of the robot arm (12) based on the difference between the design-based joint value and the actual joint value.

[0007] The above and other aspects, features, and advantages according to specific embodiments of the present disclosure will become more apparent from the detailed description below with reference to the accompanying drawings.

[0008] FIG. 1 is a drawing showing a robot system according to one embodiment.

[0009] FIG. 2 shows a calibration tool on a calibration jig according to one embodiment.

[0010] This is a drawing showing the approach.

[0011] FIG. 3 is a plan view and a cross-sectional view of a calibration jig according to one embodiment.

[0012] FIG. 4 is a drawing showing a calibration tool and a posture correction structure according to one embodiment.

[0013] FIG. 5 is a drawing showing a calibration tool according to one embodiment seated in a groove of a calibration jig.

[0014] FIG. 6 is a drawing showing a calibration tool according to one embodiment approaching a groove of a calibration jig.

[0015] FIG. 7 is a side view of a robot system according to one embodiment.

[0016] FIG. 8 is a block diagram of a robot system according to one embodiment.

[0017] FIG. 9 is a flowchart illustrating a calibration method for a robot system according to one embodiment.

[0018] FIG. 10 is a flowchart illustrating the position calibration operation of a robot system according to one embodiment.

[0019] FIG. 11 is a flowchart illustrating the posture calibration operation of a robot system according to one embodiment.

[0020] FIG. 12 is a plan view of a calibration jig according to one embodiment.

[0021] FIG. 13 is a plan view of a calibration jig according to one embodiment.

[0022] FIG. 14 is a plan view of a calibration jig according to one embodiment.

[0023] FIG. 15 is a plan view of a calibration jig according to one embodiment.

[0024] FIG. 16 is a side view of a robot system according to one embodiment.

[0025] Hereinafter, embodiments will be described in detail with reference to the attached drawings. In the description with reference to the attached drawings, identical components are given the same reference numeral regardless of the drawing number, and redundant descriptions thereof will be omitted.

[0026] The embodiments and the terms used therein are not intended to limit the technical features described herein to specific embodiments, and should be understood to include various modifications, equivalents, or substitutions of said embodiments. In connection with the description of the drawings, similar reference numerals may be used for similar or related components. The singular form of a noun corresponding to an item may include one or more of said items unless the relevant context clearly indicates otherwise. In this document, phrases such as "A or B," "at least one of A and B," "at least one of A or B," "A, B or C," "at least one of A, B and C," and "at least one of A, B, or C" may each include any one of the items listed together in the corresponding phrase, or any combination thereof. Terms such as "first," "second," or "first" or "second" may be used simply to distinguish said components from other said components and do not limit said components in any other aspect (e.g., importance or order). Where any (e.g., 1st) component is referred to as "coupled" or "connected" to another (e.g., 2nd) component, with or without the terms "functionally" or "communicationly," it means that said any component may be connected to said other component directly (e.g., via a wire), wirelessly, or through a third component.

[0027]

[0028] FIG. 1 is a drawing showing a robot system according to one embodiment.

[0029] Referring to FIG. 1, a robot system (1) according to one embodiment can easily perform calibration even after the robot is applied to a process by using a calibration jig (14) installed on the main body (11) of the robot. A robot may include many degrees of freedom and joints, and due to deformation of the mechanism and / or sensor errors that occur while operating continuously, it may be difficult to perform accurate operation with only initial calibration. In addition, if a part of the robot is replaced due to a breakdown, additional calibration must be performed, so periodic calibration is required. However, after the robot is installed, it becomes surrounded by devices such as factory equipment. As a result, it becomes difficult to install additional external devices, so work is required to disassemble the surrounding devices or move the robot for calibration. Even in the case of the simplest force sensor-based calibration system, a calibration jig must be installed externally, but since a conveyor is often installed in front of the robot, it becomes difficult to apply the calibration jig. According to one embodiment, the robot system (1) can perform calibration on its own without changing the surrounding environment. The robot system (1) according to one embodiment may include a main body (11), a robot arm (12), a calibration jig (14), and a posture correction structure (15).

[0030] The robot arm (12) may include, for example, a first robot arm (12a) installed on the left side (e.g., -x-axis direction) of the main body (11) and a second robot arm (12b) installed on the right side (e.g., +x-axis direction) of the main body (11). For example, the first robot arm (12a) may be referred to as a "robot arm" and the second robot arm (12b) as an "additional robot arm." Hereinafter, the case in which the robot system (1) is equipped with dual robot arms (12a, 12b) is described as an example, but is not limited thereto. For example, the robot system (1) may be a general service robot system equipped with a single robot arm, or it may be equipped with three or more robot arms. The robot arm (12) may include a joint (121), an end effector (122), a calibration tool (123), and a sensor (124).

[0031] A joint (121) may rotate or slide relative to an adjacent joint (121). For example, a robot arm (12) may be formed with multiple joints (121) having 7 degrees of freedom, but is not limited thereto. Multiple joints (121) may connect the main body (11) and the end effector (122).

[0032] The end effector (122) may be connected to the main body (11) by a plurality of joints (121). The end effector (122) is a part located at the end of the robot arm (12) and may include a structure (e.g., a gripper) on which a tool having a function for a specific task can be mounted when performing a specific task using the robot arm (12). For example, a calibration tool (123) for performing a calibration task may be detachably attached to the end effector (122).

[0033] The calibration tool (123) may be installed on the end effector (122). For example, the calibration tool (123) may be installed directly on the end effector (122) or indirectly on the end effector (122) through the sensor (124) as a medium. The calibration tool (123) may physically interact with the calibration jig (14) and / or the posture correction structure (15).

[0034] The calibration tool (123) may come into contact with the calibration jig (14). For example, the calibration tool (123) may be positioned at a specific point on the calibration jig (14) or moved along a specific path according to the shape of the calibration jig (14). Based on the information measured during this process (e.g., joint values ​​of each joint (121)), a calibration operation may be performed. At least a portion of the calibration tool (123) may be formed in a sphere shape. This shape can reduce the problem of damage to the calibration jig (14) or the calibration tool (123) during the process of the calibration tool (123) sliding along a specific path of the calibration jig (14). Additionally, if the end of the calibration tool (123) has a sphere shape, the calibration tool (123) may have various orientations while positioned at a specific point. According to this configuration, when the calibration tool (123) enters a specific point while the calibration work is not properly performed, the constraints can be reduced, so it may be advantageous to perform self-calibration work.

[0035] The calibration tool (123) can be coupled to the posture correction structure (15). For example, as described below, when the calibration tool (123) is fully coupled to the posture correction structure (15), the calibration tool (123) may have only one orientation. Through this configuration, a calibration operation for the orientation of the calibration tool (123) can be performed based on the information of the state in which the calibration tool (123) is coupled to the posture correction structure (15).

[0036] The sensor (124) can detect information regarding whether the calibration tool (123) is positioned at a reference point for performing a calibration operation. For example, the sensor (124) can detect information regarding an external force applied to the calibration tool (123) (e.g., a reaction force received by the calibration tool (123) from the calibration jig (14). For example, the sensor (124) may include a force sensor. For example, the sensor (124) may be installed between the calibration tool (123) and the end effector (122). When the calibration tool (123) is positioned at a specific point on the calibration jig (14) and can no longer move in a specific direction, the magnitude of the external force detected by the sensor (124) may exceed a set value. Based on this information, it can be determined whether an obstacle is located in the movement path of the calibration tool (123). Additionally, if the calibration jig (14) is manufactured in a specific shape, the information described above can determine whether the calibration tool (123) is located at a specific point. Meanwhile, the sensor (124) may include various other known means in addition to the force sensor. For example, the sensor (124) may include a torque sensor that is placed at each joint (121) of the robot arm (12) and detects the torque applied to each joint (121). By using the value detected by the torque sensor and the joint value at each joint (121), the location where the calibration tool (123) is located can be determined in a manner similar to the above. For example, the sensor (124) may be an encoder that detects the joint value of each joint (121). When a driving command is applied to each joint (121), the location of the calibration tool (123) can be determined similarly to the above based on whether the joint value of each joint (121) reaches the target value according to the driving command described above.

[0037] Meanwhile, the configurations provided in the second robot arm (12b) or the additional robot arm (12b) may be referred to as "additional joint," "additional end effector," and "additional calibration tool," respectively. Unless otherwise stated, it should be noted that the descriptions of the joint (121), end effector (122), and calibration tool (123) may apply to the "additional joint," "additional end effector," and "additional calibration tool." The additional end effector may be connected to the main body (11) by a plurality of additional joints. The additional calibration tool may be installed on the additional end effector and at least a portion of it may be formed in a spherical shape.

[0038] For example, if the calibration tool (123) is provided as a detachable tool, calibration work for the first robot arm (12a) can be performed while the calibration tool (123) is attached to the first robot arm (12a) without the need to separately provide an additional calibration tool, and calibration work for the second robot arm (12b) can be performed while the calibration tool (123) is detached from the first robot arm (12a) and attached to the second robot arm (12b).

[0039] The calibration jig (14) may be positioned so that the calibration tool (123) and / or additional calibration tool can be contacted. Through such a position, the robot system (1) can perform a self-calibration operation as described below. For example, the calibration jig (14) may be located on the main body (11). With this configuration, there is no need to provide a separate space for installing the calibration jig (14) within the workspace of the robot system (1). Additionally, the calibration jig (14) may be installed in a specific position and orientation within the main body (11). In this case, even if the robot system (1) is moved or its orientation is changed, the relative position and orientation of the calibration jig (14) with respect to the main body (11) do not change, so the calibration operation as described below can be performed without performing additional work (e.g., measuring the position of the calibration jig (14)).

[0040] The posture correction structure (15) can be combined with the calibration tool (123). An exemplary combined structure and function of the posture correction structure (15) and the calibration tool (123) will be described later.

[0041]

[0042] FIG. 2 is a drawing showing a calibration tool approaching a calibration jig according to one embodiment. FIG. 3 is a plan view and a cross-sectional view of a calibration jig according to one embodiment.

[0043] Referring to FIGS. 2 and 3, a calibration jig (14) according to one embodiment may include a plurality of reference areas (a1, a2, a3, a4), at least one guide groove (141), a central portion (142) positioned on the central side of the calibration jig (14) with respect to the guide groove (141), and a rim portion (143) positioned on the rim side of the calibration jig (14) with respect to the guide groove (141). The guide groove (141) may be understood as a portion formed as a depression compared to the central portion (142) and the rim portion (143).

[0044] Multiple reference areas (a1, a2, a3, a4) refer to specific areas formed in the calibration jig (14), and each reference area (a1, a2, a3, a4) may have a structure in which the calibration tool (123) can make three-point contact. When an object makes three-point contact with a counterpart, the object can maintain a relatively constant position relative to the counterpart. Therefore, when the calibration tool (123) is located in the reference area (a1, a2, a3, a4), a specific point (e.g., center) of the calibration tool (123) is located at a specific position relative to the main body (11). Accordingly, with the calibration tool (123) positioned in each reference area (a1, a2, a3, a4), the real joint value of each joint (121) of the robot arm (12) can be measured, and a calibration operation can be performed using the difference between the measured real joint value and the design-based joint value. In other words, the multiple reference areas (a1, a2, a3, a4) can provide reference points where the calibration tool (123) should be positioned to perform the calibration operation.

[0045] For example, the point where the calibration tool (123) and the first reference area (a1) make three-point contact may include a first point (p1) located on the edge-side inner wall (1411) of one of the mutually adjacent pair of guide grooves (141a, 141b), a second point (p2) located on the protruding line where the center-side inner wall (1412) of each of the aforementioned pair of guide grooves (141a, 141b) meet each other, and a third point (p3) located on the edge-side inner wall (1411) of the remaining guide groove (141b) of the aforementioned pair of guide grooves (141a, 141b). Meanwhile, the first point (p1), second point (p2), and third point (p3) described above are all points located on a slanted surface or corner facing the same point (e.g., the point where the bottom portion (1413) of each of the pair of guide grooves (141a, 141b) meet each other). According to this structure, even if there is an error in the initial calibration value, the end of the calibration tool (123) can reach a specific position where it makes three-point contact on the first reference area (a1) by simply moving the calibration tool (123) in the direction of the sinking of the calibration jig (14) (e.g., -y-axis direction) near the first reference area (a1). In other words, the calibration tool (123) can be moved to a specific position by only operating the robot arm (12) without the user having to perform a teaching operation to move the calibration tool (123) to a specific position. When the calibration tool (123) comes into contact with the first point (p1), second point (p2), and third point (p3) described above, the movement of the calibration tool (123) in three specific directions (e.g., +z-axis direction, -x-axis direction, and -y-axis direction) is restricted, so that it can be determined whether the calibration tool (123) is located in the first reference area (a1) based on information detected by the sensor (124).Although the first reference area (a1) has been described above, a person skilled in the art will fully understand that the same or similar description can also be applied to the second reference area (a2), the third reference area (a3), and the fourth reference area (a4).

[0046] The guide groove (141) can interconnect multiple reference areas (a1, a2, a3, a4). With this configuration, the calibration tool (123) does not need to retract completely backward (e.g., in the +x-axis direction) to move from one reference area (a1) to another reference area (a2). Since the calibration tool (123) can be positioned at each of the multiple reference areas (a1, a2, a3, a4) while moving along the guide groove (141), the time required to collect information for performing the calibration operation can be reduced.

[0047] A calibration tool (123) can make two-point contact with the guide groove (141). For example, the width of the guide groove (141) can become narrower as it moves toward the direction of the depression of the guide groove (141) (e.g., the -y-axis direction). According to this structure, even if there is an error in the initial calibration value, the calibration tool (123) can reach a certain height where it makes two-point contact on the guide groove (141) simply by moving the calibration tool (123) toward the direction of the depression of the guide groove (141). In other words, the calibration tool (123) can be moved to a specific position solely by operating the robot arm (12) without the user having to perform a teaching operation to move the calibration tool (123) to a specific position.

[0048] For example, the guide groove (141) may include a rim-side inner wall (1411) located near the rim portion (143) of the calibration jig (14), a center-side inner wall (1412) located near the center portion (142) of the calibration jig (14), and a bottom portion (1413) where the rim-side inner wall (1411) and the center-side inner wall (1412) meet each other. For example, the rim-side inner wall (1411) and / or the center-side inner wall (1412) may include an inclined surface inclined toward the bottom portion (1413). Meanwhile, it should be noted that the shape of the rim-side inner wall (1411) and / or the center-side inner wall (1412) is not necessarily limited in this way, and the rim-side inner wall (1411) and / or the center-side inner wall (1412) may include a curved surface with a recessed or protruding shape.

[0049] For example, the calibration tool (123) can be slid along the guide groove (141) in a state of close contact (i.e., in a state of two-point contact with a pair of inner walls (1411, 1412)) until it can no longer enter in the direction of the recess of the guide groove (141). Finally, the calibration tool (123) can be moved to a reference area (a1, a2, a3, a4) located between the pair of guide grooves (141).

[0050] For example, the guide groove (141) may have a closed-loop shape formed by interconnecting multiple reference areas (a1, a2, a3, a4) and forming an intaglio. With such a shape, information required for calibration can be collected simply by moving the calibration tool (123) along the guide groove (141), thereby reducing the time required for calibration. For example, the closed-loop shape may be a polygon (e.g., triangle, square, pentagon, hexagon, etc.).

[0051] The calibration jig (14) may include a first guide groove (141a) formed in a first direction (e.g., z-axis direction), a second guide groove (141b) connected to the first guide groove (141a) and formed in a second direction (e.g., y-axis direction) different from the first direction, and a third guide groove (141c) connected to the second guide groove (141b) and formed in a third direction (e.g., z-axis direction) different from the second direction. For example, at least one of the first guide groove (141a), the second guide groove (141b), and the third guide groove (141c) may have a straight shape. With such a straight shape, the calibration tool (123) can move between multiple reference areas (a1, a2, a3, a4) by the shortest distance, thereby reducing the time required for the calibration operation.

[0052] A plurality of reference areas (a1, a2, a3, a4) may include a first reference area (a1) where the first guide groove (141a) and the second guide groove (141b) meet, and a second reference area (a2) where the second guide groove (141b) and the third guide groove (141c) meet. For example, while the calibration tool (123) slides from the first reference area (a1) to the second reference area (a2), the calibration tool (123) may maintain a state of two-point contact with the inner wall (1411, 1412) of the second guide groove (141b). The above description may be applied in the same or similar way to the third guide groove (141c) formed between the second reference area (a2) and the third reference area (a3), the fourth guide groove (141d) formed between the third reference area (a3) ​​and the fourth reference area (a4), and the first guide groove (141a) formed between the fourth reference area (a4) and the first reference area (a1), and a detailed description thereof will be omitted.

[0053] A posture correction structure (15) according to one embodiment can be coupled to a calibration tool (123). For example, when the posture correction structure (15) and the calibration tool (123) are fully coupled, the calibration tool (123) can be constrained so that the calibration tool (123) has only one posture. For example, the posture correction structure (15) can be located between a plurality of reference areas (a1, a2, a3, a4). For example, the posture correction structure (15) can be formed in the central part (142). For example, the posture correction structure (15) can be located inside a closed loop formed by a plurality of guide grooves (141a, 141b, 141c, 141d). With such an arrangement, the coupling shape between the posture correction structure (15) and the calibration tool (123) can be made to have high precision. After a calibration operation is performed primarily using multiple reference areas (a1, a2, a3, a4), the position control accuracy of the robot arm (12) for the multiple reference areas (a1, a2, a3, a4) or the areas located between them can be sufficiently improved. Therefore, a calibration operation using a posture correction structure (15) secondarily can be performed with higher precision, and thus, the possibility of misalignment between the posture correction structure (15) and the calibration tool (123) is reduced, allowing the size of the posture correction structure (15) to be sufficiently reduced.

[0054] For example, the posture correction structure (15) may be formed protruding from the calibration jig (14), but is not limited thereto. For example, the posture correction structure (15) may be formed recessed from the calibration jig (14). Meanwhile, it should be noted that the posture correction structure (15) may be formed protruding or recessed from a part other than the calibration jig (14) (e.g., the main body (11)).

[0055]

[0056] FIG. 4 is a drawing showing a calibration tool and a posture correction structure according to one embodiment.

[0057] Referring to FIG. 4, a calibration tool (123) according to one embodiment may include a tool body (1231) and a calibration structure coupling part (1232). At least a portion of the tool body (1231) may be formed in a spherical shape.

[0058] The correction structure coupling portion (1232) can be coupled to the posture correction structure (15). For example, the correction structure coupling portion (1232) can be formed at the farthest end in the longitudinal direction (e.g., +z_t axis direction) of the calibration tool (123) from the center (O_t) of the tool body (1231). For example, the correction structure coupling portion (1232) can be formed as a recess from the surface of the calibration tool (123). With such a shape, the problem of the calibration jig (14) being damaged by the correction structure coupling portion (1232) can be reduced during the process of the calibration tool (123) sliding on the calibration jig (14).

[0059] For example, the posture correction structure (15) may have a shape in which the cross-sectional area narrows as it moves in the protruding direction (e.g., the +y-axis direction in FIG. 1), and the correction structure coupling part (1232) may have a shape in which the cross-sectional area narrows as it moves in the recessed direction (e.g., the -z_t-axis direction). According to such a shape, when the correction structure coupling part (1232) is brought close to the posture correction structure (15), the posture correction structure (15) can be slidably coupled into the correction structure coupling part (1232). Therefore, even if there is an error in the calibration value, the posture correction structure (15) and the correction structure coupling part (1232) can be self-aligned and coupled by simply moving the calibration tool (123) in the opposite direction of the protruding direction of the posture correction structure (15) (the -y-axis direction in FIG. 1) near the posture correction structure (15). In other words, the calibration tool (123) can be moved to a specific position solely by operating the robot arm (12) without the user having to perform a teaching task of moving the calibration tool (123) to a specific position. For example, the posture correction structure (15) and the correction structure coupling part (1232) may each have a corresponding triangular pyramid shape, but are not limited thereto and may have various pyramid shapes.

[0060] The correction structure coupling part (1232) may include a plurality of recesses (1232a) and protrusions (1232b) arranged alternately along the circumferential direction. The plurality of recesses (1232a) and protrusions (1232b) may cause the surfaces facing each other among the correction structure coupling part (1232) and the posture correction structure (15) to make line contact. With such a shape, when the correction structure coupling part (1232) and the posture correction structure (15) make surface contact with each other, the problem of difficulty in separating them due to frictional force can be reduced.

[0061] The posture correction structure (15) and the correction structure coupling part (1232) can restrict the rotational movement (e.g., rotation around the z_t axis) of the calibration tool (123) when they are fully coupled to each other. For example, when the posture correction structure (15) and the correction structure coupling part (1232) are fully coupled, the calibration tool (123) can be constrained so that the calibration tool (123) has only one posture. In this way, if there is a point where the position and orientation of the calibration tool (123) and the end effector (122, see FIG. 1) connected thereto can both be determined, the coordinate system can be corrected based on that point. For example, if the robot system (1) includes multiple robot arms (12), the coordinate systems of the multiple robot arms (12) can all be corrected based on the same posture correction structure (15). By performing such origin correction work, multiple robot arms (12) can share the same coordinate system, thereby improving the efficiency of simultaneous operation of multiple robot arms (12).

[0062]

[0063] FIG. 5 is a drawing showing a calibration tool according to one embodiment seated in a groove of a calibration jig.

[0064] Referring to FIG. 5, a calibration tool (123) according to one embodiment may include a tool body (1231) and a calibration structure coupling part (1232). A calibration jig (14) according to one embodiment may include a guide groove (141), a central part (142), and a rim part (143). The guide groove (141) may include an inner wall on the rim side (1411), an inner wall on the center side (1412), and a bottom part (1413).

[0065] For example, the angle θ_j between the edge-side inner wall (1411) and the center-side inner wall (1412) can be greater than the maximum angle θ_t between the edges of the correction structure coupling part (1232) with respect to the center (O_t) of the calibration tool (123). According to such a structure, the problem of the edges of the correction structure coupling part (1232) contacting the inner walls (1411, 1412) of the guide groove (141) can be reduced. For example, the angle θ_j can be more than twice as large as the angle θ_t. According to such a structure, even when the calibration tool (123) is not in an orientation perpendicular to the calibration jig (14) (e.g., y-axis direction), the problem of the edges of the correction structure coupling part (1232) contacting the inner walls (1411, 1412) of the guide groove (141) can be reduced.

[0066]

[0067] FIG. 6 is a drawing showing a calibration tool according to one embodiment approaching a groove of a calibration jig.

[0068] Referring to FIG. 6, a calibration jig (14') according to one embodiment (e.g., 14 in FIG. 1) may include a guide groove (141), a central portion (142'), and a rim portion (143').

[0069] According to one embodiment, half the width value (W / 2) of the guide groove (141) may be greater than the design-based maximum error distance (E_max) of the end effector (122, see FIG. 1). Here, "design-based maximum error distance" can be understood as the maximum error that the robot arm (12, see FIG. 1) may have, taking into account the design CAD data and assembly tolerances of the robot arm (12). In other words, the width of the guide groove (141) may be determined based on the positional accuracy of the end effector (122) before performing the calibration operation. With this configuration, even if there is an error in the initial calibration value, the problem of the end effector (122) and the calibration tool (123) connected thereto moving out of the guide groove (141) and entering the central part (142') or the edge part (143') can be reduced.

[0070] According to one embodiment, the central portion (142') and / or the edge portion (143') may have a shape inclined toward the adjacent guide groove (141). With such a shape, even without increasing the width of the guide groove (141) as described above, when the calibration tool (123) enters the central portion (142') or the edge portion (143') due to an error in the initial calibration value, the calibration tool (123) may be guided toward the guide groove (141) along the inclined shape of the central portion (142') or the edge portion (143').

[0071]

[0072] FIG. 7 is a side view of a robot system according to one embodiment.

[0073] Referring to FIG. 7, a robot system (2) according to one embodiment (e.g., robot system (1) of FIG. 1) may include a main body (11), a robot arm (12), a first calibration jig (14a) (e.g., calibration jig (14) of FIG. 1), a second calibration jig (14b) (e.g., calibration jig (14) of FIG. 1), a first posture correction structure (15a) (e.g., posture correction structure (15) of FIG. 1) and a second posture correction structure (15b) (e.g., posture correction structure (15) of FIG. 1). For example, the first calibration jig (14a) and the first posture correction structure (15a) may be referred to as the "calibration jig" and "posture correction structure," respectively, and the second calibration jig (14b) and the second posture correction structure (15b) may be referred to as the "additional calibration jig" and "additional posture correction structure," respectively.

[0074] According to one embodiment, the center positions of the calibration tool (e.g., 123 in FIG. 1) when it is in three-point contact with each of the multiple reference areas (e.g., a1, a2, a3, a4 in FIG. 2) formed on the first calibration jig (14a) can be placed on the same first plane (P1). With this configuration, by controlling the force according to the same standard in each reference area (a1, a2, a3, a4), it is possible to verify whether the calibration tool (123) is accurately seated in each reference area (a1, a2, a3, a4), thereby reducing the amount of control calculation. Additionally, since it is possible to manufacture the first calibration jig (14a) in the same or symmetrical shape, the ease of manufacturing the first calibration jig (14a) can be improved.

[0075] The second calibration jig (14b) can be positioned so that the calibration tool (123) can make contact, just like the first calibration jig (14a). The second calibration jig (14b) may include a plurality of additional reference areas (e.g., a1, a2, a3, a4 in FIG. 2) that the calibration tool (123) can make three-point contact with, and at least one additional guide groove (e.g., 141 in FIG. 2).

[0076] According to one embodiment, the center positions of the calibration tool (123) when the calibration tool (123) is in three-point contact with each of a plurality of additional reference areas (a1, a2, a3, a4) can be placed on the same second plane (P2).

[0077] For example, among the multiple joints (121) connected to the end effector (122, see FIG. 1), the joint (121) closest to the main body (11) is connected to the main body (11) at a point (O_a), and the positions of the first plane (P1) and the second plane (P2) may differ from each other. With this configuration, calibration can be performed based on the joint values ​​in a state of three-point contact with reference regions located at different positions with respect to the aforementioned point O_a, and calibration for height can be performed based on the aforementioned joint values ​​and height difference.

[0078] For example, the first calibration jig (14a) and the second calibration jig (14b) can be understood as being positioned at offset from each other in the thickness direction of the jig. For example, a pair of calibration jigs (14a, 14b) may be positioned on the front and rear of the main body (11), respectively, or on the left and rear of the main body (11), respectively.

[0079]

[0080] FIG. 8 is a block diagram of a robot system according to one embodiment.

[0081] Referring to FIG. 8, a robot system (3) according to one embodiment (e.g., robot system (1) of FIG. 1, robot system (2) of FIG. 7) may include a main body (e.g., main body (11) of FIG. 1), a robot arm (e.g., robot arm (12) of FIG. 1), a calibration jig (e.g., calibration jig (14) of FIG. 1), a posture correction structure (e.g., posture correction structure (15) of FIG. 1), a processor (16), a memory (17), a sensor (124), and a driving source (125).

[0082] The processor (16) can drive the driving source (125) based on information received from the sensor (124) and / or memory (17). For example, the processor (16) may include a plurality of processors. For example, the processor (16) may include a main processor for driving the robot arm (12) of the robot system (3) and an auxiliary processor for performing calibration operations. Alternatively, it should be noted that both driving the robot arm (12) and calibration operations may be performed within the same processor (16).

[0083] Information for driving the robot system (3) may be stored in the memory (17). For example, design CAD data of the robot arm (12) and / or design-based kinematic equations may be stored in the memory (17). For example, the memory (17) may store design-based joint values, real joint values, and calculated joint values ​​obtained during the calibration process, as well as kinematic equations adjusted through the calibration process.

[0084] The sensor (124) may include, for example, means for detecting the reaction force received by the calibration tool (123) from the calibration jig (14) (e.g., force sensor or torque sensor). The sensor (124) may include, for example, means for detecting the actual joint value (e.g., encoder). According to one embodiment, self-calibration is possible solely through the configuration of the robot system (1) without using an external device (e.g., laser measuring equipment), so the cost and space for calibration can be reduced.

[0085] The driving source (125) can generate power to move each joint of the robot arm (12). The driving source (125) may include, for example, a rotary motor capable of driving a rotary joint and / or a linear motor capable of driving a sliding joint.

[0086]

[0087] FIG. 9 is a flowchart illustrating a calibration method for a robot system according to one embodiment.

[0088] Referring to FIGS. 1, 8 and 9, a calibration method for a robot system (1) according to one embodiment may include: a calibration tool (123) mounted on the end of a robot arm (12) (91); a calibration equation of motion of the robot arm (12) for position using a calibration jig (14) (92); a calibration equation of motion of the robot arm (12) for orientation using an orientation correction structure (15) (93); a calibration origin for the robot arm (12) (94); and a determination (95) of whether calibration has been completed for all robot arms (12).

[0089] Operation 91 may be performed manually by a user or automatically by a processor (16) through the operation of a robot arm (12) and an end effector (122). For example, a calibration tool (123) may be mounted on each of a plurality of robot arms (12a, 12b). Meanwhile, it should be noted that in operation 91, the same calibration tool (123) may be detached from one robot arm (12a) and then mounted on another robot arm (12b).

[0090] Exemplary operations for operations 92 and 93 will be described later.

[0091] In operation 94, the processor (16) can correct the origin of the coordinate system of the robot arm (12) to the position of the posture correction structure (15). The processor (16) can correct the origin of the coordinate system of the robot arm (12) by transforming the transformation matrix of the kinematic equation based on the kinematic equation of the robot arm (12) and the coordinates of the posture correction structure (15) obtained prior to operation 94. Operation 94 is performed for all robot arms (12) so that all robot arms (12) can operate based on the same coordinate system.

[0092] In operation 95, the processor (16) may terminate the calibration method when the calibration operation is completed for all robot arms (12). If the calibration operation is not completed for all robot arms (12), operations 91 through 94 may be repeated for the robot arms (12) for which the calibration operation is not completed.

[0093] For example, if the robot system (1) includes at least one additional robot arm (12b) in addition to the robot arm (12a), the calibration method of the robot system (1) according to one embodiment may include: (i) adjusting the position parameter of the equation of motion of the additional robot arm (12b) using a calibration jig (14) while the calibration tool (123) is mounted on the end of the additional robot arm (12b); (ii) adjusting the position parameter of the equation of motion of the additional robot arm (12b) using a posture correction structure (15) while the calibration tool (123) is mounted on the end of the additional robot arm (12b); and (iii) correcting the origin of the additional robot arm (12b) to the position of the posture correction structure (15).

[0094]

[0095] FIG. 10 is a flowchart illustrating the position calibration operation of a robot system according to one embodiment.

[0096] Referring to FIGS. 1, 8 and 10, a position calibration operation (92) of a robot system (1) according to one embodiment comprises: an operation (921) of bringing a calibration tool (123) to a reference area (a1, a2, a3, a4); an operation (922) of determining whether the calibration tool (123) is in three-point contact with the reference area (a1, a2, a3, a4); an operation (923) of moving the calibration tool (123); an operation (924) of storing a real joint value; an operation (925) of determining whether a real joint value has been stored for all reference areas (a1, a2, a3, a4); an operation (926) of moving the calibration tool (123) to the next reference area (a1, a2, a3, a4); and adjusting a parameter for the position of the equation of motion of the robot arm (12). It may include operation (927).

[0097] In operation 921, the processor (16) can drive each joint (121) of the robot arm (12) by inputting a design-based joint value determined through a design-based equation to a driving source (125) so that the calibration tool (123) approaches the first reference area (a1) among a plurality of reference areas (a1, a2, a3, a4), while the calibration tool (123) is mounted on the end of the robot arm (12). Assuming that calibration is not properly performed, the calibration tool (123) may not make three-point contact with the first reference area (a1) with only operation 921.

[0098] In operation 922, the processor (16) can determine whether the calibration tool (123) has made three-point contact with the first reference area (a1) based on information detected by the sensor (124). When using the calibration jig (14) according to one embodiment, if the calibration tool (123) has made three-point contact with the first reference area (a1), movement is restricted in three specific directions, so the three-point contact can be determined through the value detected by the sensor (124). For example, in operation 922, the sensor (124) can detect the reaction force received by the calibration tool (123) from the calibration jig (14). The processor (16) can determine whether the calibration tool (123) has made three-point contact with the first reference area (a1) based on the magnitude of the reaction force detected by the sensor (124).

[0099] In operation 923, the processor (16) can drive the robot arm (12) so that the calibration tool (123) makes three-point contact with reference areas (a1, a2, a3, a4). When using a calibration jig (14) according to one embodiment, the end of the calibration tool (123) can reach a certain position where it makes three-point contact on the first reference area (a1) by only moving the calibration tool (123) in the vicinity of the first reference area (a1) toward the direction of the recess of the calibration jig (14). Operation 923 can be performed until the calibration tool (123) makes three-point contact with the first reference area (a1). Operation 923 can be performed, for example, in a slide-fit manner. Here, "slide fit" means a method in which the first structure slides and moves in a state where it is in close, fitting contact with the second structure with sufficient pressure, until it can no longer move in the direction of movement. In operation 923, the processor (16) can move the calibration tool (123) in a slide fit manner until it reaches each reference area (a1, a2, a3, a4) based on information collected from the sensor (124).

[0100] In operation 924, with the calibration tool (123) in three-point contact with the first reference area (a1), the processor (16) can store the actual joint values ​​of each joint (121) of the robot arm (12) in memory (17).

[0101] Through operations 925 and 926, the above-described operations 921 to 924 can be performed for all reference regions (a1, a2, a3, a4), including the first reference region (a1).

[0102] In operation 926, the processor (16) can drive the driving source (125) of each joint (121) so that the calibration tool (123) moves along each guide groove (141) in a slide-fit manner until it reaches the next reference area (a1, a2, a3, a4), based on information collected from the sensor (124). For example, in operation 926, the processor (16) can drive the robot arm (12) so that the calibration tool (123) moves from the first reference area (a1) to the second reference area (a2) along the guide groove (141). For example, the processor (16) can drive each joint (121) of the robot arm (12) so that, based on information collected from the sensor (124), the calibration tool (123) slides along the guide groove (141) while in two-point contact with the inner wall (1411, 1412) of the guide groove (141).

[0103] In operation 927, the processor (16) can adjust the position parameter of the equation of motion of the robot arm (12) based on the difference between the design-based joint value and the real joint value stored in memory (17). For example, operation 927 can be performed based on the difference between the design-based joint value and the real joint value for each of a plurality of reference regions (a1, a2, a3, a4).

[0104] Meanwhile, although it is shown that operation 927 is performed after operation 925, it should be noted that, alternatively, it may be performed after the calibration tool (123) makes three-point contact with each reference area (a1, a2, a3, a4) and before performing operation 925.

[0105]

[0106] FIG. 11 is a flowchart illustrating the posture calibration operation of a robot system according to one embodiment.

[0107] Referring to FIGS. 1, FIGS. 8 and FIGS. 11, a posture calibration operation (93) of a robot system (1) according to one embodiment may include an operation (931) of bringing a calibration tool (123) to a posture correction structure (15), an operation (932) of determining whether the calibration tool (123) is coupled to the posture correction structure (15), an operation (933) of moving the calibration tool (123), an operation (934) of storing a real joint value, and an operation (935) of adjusting parameters for the orientation of the equation of motion of the robot arm (12).

[0108] In operation 931, the processor (16) can drive a drive source (125) that powers each joint (121) of the robot arm (12) so that the correction structure coupling part (1232) approaches the posture correction structure (15). For example, operation 931 can be performed after operation (927, see FIG. 10) which adjusts parameters for position. In this case, the processor (16) can drive each joint (121) of the robot arm (12) with a calculated joint value calculated through the equation of motion in which the parameters were adjusted in operation 927. According to this sequence, posture calibration can be performed more precisely compared to when using design-based equations of motion.

[0109] In operation 932, the processor (16) can determine whether the correction structure coupling part (1232) is coupled to the posture correction structure (15) based on information detected by the sensor (124). When using the posture correction structure (15) according to one embodiment, if the correction structure coupling part (1232) is coupled to the posture correction structure (15), the calibration tool (123) will have only one posture, so the coupling can be determined through the value detected by the sensor (124).

[0110] In operation 933, the processor (16) can drive the robot arm (12) so that the correction structure coupling part (1232) is coupled to the posture correction structure (15). When using the posture correction structure (15) according to one embodiment, the posture correction structure (15) and the correction structure coupling part (1232) can be coupled while self-aligning by simply moving the calibration tool (123) in the vicinity of the posture correction structure (15) in the opposite direction of the protrusion direction of the posture correction structure (15). Operation 923 can be performed until the posture correction structure (15) and the correction structure coupling part (1232) are coupled to each other. Operation 923 can be performed, for example, in a slide-fit manner.

[0111] In operation 934, with the correction structure coupling part (1232) coupled to the posture correction structure (15), the actual joint value of each joint (121) of the robot arm (12) can be stored in memory (17).

[0112] In operation 935, the processor (16) can adjust the parameters for the posture of the equation of motion of the robot arm (12) based on the difference between the calculated joint value and the actual joint value through the equation of motion adjusted through the calibration operation.

[0113]

[0114] Embodiments may be implemented as software comprising one or more instructions stored in a storage medium (e.g., memory (17)) that is readable by a machine (e.g., robot system (1)). For example, a processor (16) of the machine (e.g., robot system (1)) may call at least one of the one or more instructions stored from the storage medium and execute it. This enables the machine to operate to perform at least one function according to the at least one called instruction. The one or more instructions may include code generated by a compiler or code that can be executed by an interpreter. The storage medium readable by the machine may be provided in the form of a non-transitory storage medium. Here, 'non-transitory' simply means that the storage medium is a tangible device and does not contain a signal (e.g., electromagnetic waves), and this term does not distinguish between cases where data is stored semi-permanently and cases where it is stored temporarily in the storage medium.

[0115] According to embodiments, each component (e.g., module or program) of the components described above may include a singular or multiple entities, and some of the multiple entities may be separated and placed in other components. According to embodiments, one or more of the components or operations among the aforementioned components may be omitted, or one or more other components or operations may be added. Generally or additionally, multiple components (e.g., module or program) may be integrated into a single component. In this case, the integrated component may perform one or more functions of each of the multiple components in the same or similar manner as those performed by the corresponding component among the multiple components prior to integration. According to embodiments, operations performed by the module, program, or other components may be executed sequentially, in parallel, iteratively, or heuristically, or one or more of the operations may be executed in a different order, omitted, or one or more other operations may be added.

[0116]

[0117] FIGS. 12 to 14 are plan views of a calibration jig according to one embodiment.

[0118] Referring to FIG. 12, a calibration jig (24) (e.g., 14 of FIG. 1) according to one embodiment may include a triangular guide groove (241), a central portion (242), and a rim portion (243). The guide groove (241) may include an inner wall on the rim side (2411), an inner wall on the center side (2412), and a bottom portion (2413).

[0119] Referring to FIG. 13, a calibration jig (34) (e.g., 14 of FIG. 1) according to one embodiment may include a convex hexagonal guide groove (341), a central portion (342), and a rim portion (343). The guide groove (341) may include a rim-side inner wall (3411), a central-side inner wall (3412), and a bottom portion (3413).

[0120] Referring to FIG. 14, a calibration jig (44) according to one embodiment (e.g., 14 of FIG. 1) may include a concave octagonal guide groove (441), a central portion (442), and a rim portion (443). The guide groove (441) may include a rim-side inner wall (4411), a central-side inner wall (4412), and a bottom portion (4413).

[0121] As described above, it is noted that the calibration jig (11, 24, 34, 44) according to one embodiment may include guide grooves (141, 241, 341, 441) having various closed-loop shapes. For example, it is noted that the closed-loop shape may have a concave polygon shape as well as a convex polygon shape.

[0122]

[0123] FIG. 15 is a plan view of a calibration jig according to one embodiment.

[0124] Referring to FIG. 15, a calibration jig (14) according to one embodiment may include a guide groove (141), a central portion (142), and a rim portion (143). The guide groove (141) may include an inner wall on the rim side (1411), an inner wall on the center side (1412), and a bottom portion (1413).

[0125] A posture correction structure (15') according to one embodiment may have a non-point-symmetric shape. With such a shape, the angle at which the calibration tool (123) can be coupled to the posture correction structure (15') can be determined as a single angle. Therefore, for the calibration operation, there is no need to calculate the angle at which the calibration tool (123) is coupled to the posture correction structure (15'), so the amount of calculation for the calibration operation can be reduced.

[0126] Meanwhile, unless otherwise stated, it should be noted that the scope of the present invention is not limited to cases where the posture correction structure (15') has a non-point-symmetric shape. For example, if the posture correction structure (15') has a point-symmetric shape, the process of combining the calibration tool (123) and the posture correction structure (15') or the movement path can be simplified, and consequently, the limitation condition regarding the length of the calibration tool (123) can be relaxed.

[0127]

[0128] FIG. 16 is a side view of a robot system according to one embodiment.

[0129] Referring to FIG. 16, a robot system (4) (e.g., 1 in FIG. 1) according to one embodiment may include a main body (11') (e.g., 11 in FIG. 1), a robot arm (12), a first calibration jig (14a) (e.g., 14 in FIG. 1), a second calibration jig (14b), a first posture correction structure (15a) (e.g., 15 in FIG. 1), and a second posture correction structure (15b).

[0130] According to one embodiment, the main body (11') may include an installation space (S) in which a first calibration jig (14a) and / or a second calibration jig (14b) can be installed. The first calibration jig (14a) and / or the second calibration jig (14b) may be provided to be detachably attached to the installation space (S). Meanwhile, it should be noted that, not limited thereto, the first calibration jig (14a) and / or the second calibration jig (14b) may be integrally formed with the main body (11').

[0131] For example, with the first calibration jig (14a) and / or the second calibration jig (14b) installed in the robot system (1), a calibration operation can be performed based on the local coordinate system of the robot itself through the method described above.

[0132] If necessary, the first calibration jig (14a) and / or the second calibration jig (14b) may be separated from the main body (11') and placed on another part (e.g., a conveyor mechanism) installed in the space where the robot system (1) is installed. In this state, the first calibration jig (14a) and / or the second calibration jig (14b) may be used to perform a calibration operation based on a universal coordinate system for the space where the robot system (1) is installed.

[0133]

[0134] A robot system (1; 2; 3; 4) according to one embodiment may include a main body (11; 11'), an end effector (122) connected to the main body (11; 11') by a plurality of joints (121), a calibration tool (123) installed on the end effector (122) and having at least a portion formed in a spherical shape, and a calibration jig (14; 14a; 14b; 14'; 24; 34; 44) disposed at a position where the calibration tool (123) can contact it, and including a plurality of reference areas (a1, a2, a3, a4) where the calibration tool (123) can make three-point contact.

[0135] According to one embodiment, the calibration jig (14; 14a; 14b; 14'; 24; 34; 44) may be located on the main body (11; 11').

[0136] According to one embodiment, the calibration jig (14; 14a; 14b; 14'; 24; 34; 44) may further include at least one guide groove (141; 241; 341; 441) that interconnects the plurality of reference areas (a1, a2, a3, a4).

[0137] According to one embodiment, the calibration jig (14; 14a; 14b; 14'; 24; 34; 44) may further include a first guide groove (141a) formed in a first direction, a second guide groove (141b) connected to the first guide groove (141a) and formed in a second direction different from the first direction, and a third guide groove (141c) connected to the second guide groove (141b) and formed in a third direction different from the second direction. For example, the plurality of reference areas (a1, a2, a3, a4) may include a first reference area (a1) where the first guide groove (141a) and the second guide groove (141b) meet, and a second reference area (a2) where the second guide groove (141b) and the third guide groove (141c) meet.

[0138] According to one embodiment, the second guide groove (141b) may have a shape capable of maintaining two-point contact with the inner wall (1411, 1412) of the second guide groove (141b) while the calibration tool (123) slides from the first reference area (a1) to the second reference area (a2).

[0139] According to one embodiment, at least one of the first guide groove (141a), the second guide groove (141b), and the third guide groove (141c) may have a straight shape.

[0140] According to one embodiment, the width of the at least one guide groove (141; 241; 341; 441) may become narrower as it moves toward the recessed direction of the at least one guide groove (141; 241; 341; 441).

[0141] According to one embodiment, the calibration jig (14; 14a; 14b; 14'; 24; 34; 44) may include a guide groove (141; 241; 341; 441) in the shape of a closed loop formed by intaglio, which interconnects the plurality of reference areas (a1, a2, a3, a4).

[0142] According to one embodiment, the robot system (1; 2; 3; 4) may further include a posture correction structure (15; 15a; 15b; 15') located between the plurality of reference areas (a1, a2, a3, a4). For example, the calibration tool (123) may include a calibration structure coupling part (1232) that can be coupled to the posture correction structure (15; 15a; 15b; 15'). For example, the posture correction structure (15; 15a; 15b; 15') and the calibration structure coupling part (1232) may restrict the rotational movement of the calibration tool (123) in place when they are fully coupled to each other.

[0143] According to one embodiment, the posture correction structure (15; 15a; 15b; 15') may be formed protruding from the calibration jig (14; 14a; 14b; 14'; 24; 34; 44). For example, the correction structure coupling portion (1232) may be formed recessed from the surface of the calibration tool (123).

[0144] According to one embodiment, the calibration jig (14; 14a; 14b; 14'; 24; 34; 44) may further include a plurality of guide grooves (141; 241; 341; 441) that are interconnected and capable of two-point contact with the calibration tool (123). For example, the posture correction structure (15; 15a; 15b; 15') may be located inside a closed loop formed by the plurality of guide grooves (141; 241; 341; 441).

[0145] According to one embodiment, the robot system (1; 2; 3; 4) may further include an additional end effector (122) connected to the main body (11; 11') by a plurality of joints (121), and an additional calibration tool (123) installed on the additional end effector (122) and having at least a portion formed in a spherical shape. For example, the calibration jig (14; 14a; 14b; 14'; 24; 34; 44) may be positioned so that the additional calibration tool (123) can contact it.

[0146] According to one embodiment, the center positions of the calibration tool (123) when the calibration tool (123) is in three-point contact with each of the plurality of reference areas (a1, a2, a3, a4) can be placed on the same first plane (P1).

[0147] According to one embodiment, the robot system (1; 2; 3; 4) may further include an additional calibration jig (14; 14a; 14b; 14'; 24; 34; 44) which is positioned so that the calibration tool (123) can make contact, and which includes a plurality of additional reference areas (a1, a2, a3, a4) to which the calibration tool (123) can make three-point contact. For example, the center positions of the calibration tool (123) when the calibration tool (123) is in three-point contact with each of the plurality of additional reference areas (a1, a2, a3, a4) may be placed on the same second plane (P2). For example, the positions of the first plane (P1) and the second plane (P2) may differ from each other based on the point where the joint (121) closest to the main body (11; 11') among the multiple joints (121) connected to the end effector (122) is connected to the main body (11; 11').

[0148] A robot system (1; 2; 3; 4) according to one embodiment may include a main body (11; 11'), an end effector (122) connected to the main body (11; 11') by a plurality of joints (121), a calibration tool (123) installed on the end effector (122) and having at least a portion formed in a spherical shape, and a calibration jig (14; 14a; 14b; 14'; 24; 34; 44) installed on the main body (11; 11') and comprising a plurality of reference areas (a1, a2, a3, a4) to which the calibration tool (123) can make three-point contact, and at least one guide groove (141; 241; 341; 441) interconnecting the plurality of reference areas (a1, a2, a3, a4).

[0149] According to one embodiment, a calibration method for a robot system (1; 2; 3; 4) using a calibration jig (14; 14a; 14b; 14'; 24; 34; 44) comprising a plurality of reference regions (a1, a2, a3, a4) that can be three-point contacted by a calibration tool (123) comprises, with the calibration tool (123) mounted on the end of a robot arm (12), driving each joint (121) of the robot arm (12) with a design-based joint value determined through a design-based equation of motion so that the calibration tool (123) approaches a first reference region (a1) among the plurality of reference regions (a1, a2, a3, a4), and driving the robot arm (12) until the calibration tool (123) makes three-point contact with the first reference region (a1), 923), the calibration tool (123) may include an operation (924) of storing the actual joint value of each joint (121) of the robot arm (12) while the calibration tool (123) is in three-point contact with the first reference area (a1), and an operation (927) of adjusting the parameter for the position of the equation of motion of the robot arm (12) based on the difference between the design-based joint value and the actual joint value.

[0150] According to one embodiment, the operation (927) of adjusting the parameter for the position may be performed based on the difference between the design-based joint value and the actual joint value for each of the plurality of reference areas (a1, a2, a3, a4). For example, the calibration jig (14; 14a; 14b; 14'; 24; 34; 44) may further include a guide groove (141; 241; 341; 441) that interconnects the first reference area (a1) and the second reference area (a2) among the plurality of reference areas (a1, a2, a3, a4). A calibration method for a robot system (1; 2; 3; 4) according to one embodiment may further include an operation (926) of driving the robot arm (12) so that the calibration tool (123) moves from the first reference area (a1) to the second reference area (a2) along the guide groove (141; 241; 341; 441).

[0151] According to one embodiment, the robot system (1; 2; 3; 4) may further include a posture correction structure (15; 15a; 15b; 15') located between the plurality of reference areas (a1, a2, a3, a4). For example, the calibration tool (123) may include a correction structure coupling part (1232) that can be coupled to the posture correction structure (15; 15a; 15b; 15'). A calibration method for a robot system (1; 2; 3; 4) according to one embodiment is performed after an operation (927) of adjusting parameters for the position, and includes: an operation (931) of driving each joint (121) of the robot arm (12) with joint values ​​calculated through a parameter-adjusted equation of motion so that the correction structure coupling part (1232) approaches the posture correction structure (15; 15a; 15b; 15'); an operation (932, 933) of driving the robot arm (12) until the correction structure coupling part (1232) is coupled to the posture correction structure (15; 15a; 15b; 15'); an operation (933) of storing actual joint values ​​of each joint (121) of the robot arm (12) while the correction structure coupling part (1232) is coupled to the posture correction structure (15; 15a; 15b; 15'); and the Based on the difference between the calculated joint value and the actual joint value, the operation (934) of adjusting the parameters for the posture of the equation of motion of the robot arm (12) may be further included.

[0152] According to one embodiment, the calibration method of the robot system (1; 2; 3; 4) may further include an operation (94) of correcting the origin of the coordinate system of the robot arm (12) to the position of the posture correction structure (15; 15a; 15b; 15').

[0153] According to one embodiment, the robot system (1; 2; 3; 4) may further include at least one additional robot arm (12) in addition to the robot arm (12). According to one embodiment, the calibration method of a robot system (1; 2; 3; 4) may further include: an operation (92) of adjusting the position parameters of the equation of motion of the additional robot arm (12) using the calibration jig (14; 14a; 14b; 14'; 24; 34; 44) while the calibration tool (123) is mounted on the end of the additional robot arm (12); an operation (93) of adjusting the posture parameters of the equation of motion of the additional robot arm (12) using the posture correction structure (15; 15a; 15b; 15') while the calibration tool (123) is mounted on the end of the additional robot arm (12); and an operation (94) of correcting the origin of the coordinate system of the additional robot arm (12) to the position of the posture correction structure (15; 15a; 15b; 15').

[0154] According to one embodiment, the main body (11; 11') may include an installation space (S) in which the calibration jig (14; 14a; 14b; 14'; 24; 34; 44) can be installed. For example, the calibration jig (14; 14a; 14b; 14'; 24; 34; 44) may be detachably attached to the installation space (S).

[0155] According to one embodiment, half the width of the at least one guide groove (141; 241; 341; 441) may be greater than the design-based maximum error distance of the end effector (122).

[0156] According to one embodiment, the at least one guide groove (141; 241; 341; 441) may include a rim-side inner wall (1411) located close to the rim portion (143) of the calibration jig (14; 14a; 14b; 14'; 24; 34; 44), a center-side inner wall (1412) located close to the center portion (142) of the calibration jig (14; 14a; 14b; 14'; 24; 34; 44), and a bottom portion (1413) where the rim-side inner wall (1411) and the center-side inner wall (1412) meet each other. For example, the angle (θ_j) between the rim-side inner wall (1411) and the center-side inner wall (1412) may be greater than the maximum angle (θ_t) between the rims of the correction structure joint (1232) with respect to the center (O_t) of the calibration tool (123).

[0157] According to one embodiment, the posture correction structure (15; 15a; 15b; 15') may have a shape in which the cross-sectional area narrows as it moves toward the protruding direction. For example, the correction structure coupling part (1232) may have a shape in which the cross-sectional area narrows as it moves toward the recessed direction.

[0158] According to one embodiment, a calibration method for a robot system (1; 2; 3; 4) may further include an operation of detecting a reaction force received by the calibration tool (123) from the calibration jig (14; 14a; 14b; 14'; 24; 34; 44). For example, whether the calibration tool (123) is in three-point contact with the first reference area (a1) may be determined based on the magnitude of the reaction force.

[0159] According to one embodiment, each joint (121) of the robot arm (12) can be driven so that while the calibration tool (123) moves along the guide groove (141; 241; 341; 441), the calibration tool (123) slides while in two-point contact with the inner wall (1411, 1412) of the guide groove (141; 241; 341; 441).

[0160]

[0161] According to one embodiment, the embodiments of this document are intended to be exemplary and not limiting. Various modifications to the details of the disclosure may be made, including to the appended claims and their equivalents. Any of the embodiment(s) described herein may be used in combination with the embodiment(s) described herein.

Claims

1. Main body (11; 11'); An end effector (122) connected to the main body (11; 11') by a plurality of joints (121); A calibration tool (123) installed on the end effector (122) and having at least a portion formed in a spherical shape; and A calibration jig (14; 14a; 14b; 14'; 24; 34; 44) comprising a plurality of reference areas (a1, a2, a3, a4) that are three-point contactable with the calibration tool (123), wherein the calibration tool (123) is positioned in a contactable location, and the calibration tool (123) is contactable at a plurality of reference areas (a1, a2, a3, a4). Robot system (1; 2; 3; 4).

2. In Paragraph 1, The calibration jig (14; 14a; 14b; 14'; 24; 34; 44) is located on the main body (11; 11'), Robot system (1; 2; 3; 4).

3. In Paragraph 1 or 2, The above calibration jig (14; 14a; 14b; 14'; 24; 34; 44) is, It further includes at least one guide groove (141; 241; 341; 441) interconnecting the plurality of reference areas (a1, a2, a3, a4), and The above at least one guide groove (141; 241; 341; 441) is, The calibration tool (123) has a shape capable of maintaining a state of two-point contact with the inner wall (1411, 1412) of the at least one guide groove (141; 241; 341; 441) while sliding between the plurality of reference areas (a1, a2, a3, a4). Robot system (1; 2; 3; 4).

4. In any one of paragraphs 1 through 3, The above calibration jig (14; 14a; 14b; 14'; 24; 34; 44) is, A first guide groove (141a) formed in a first direction; A second guide groove (141b) connected to the first guide groove (141a) and formed in a second direction different from the first direction; and It further includes a third guide groove (141c) connected to the second guide groove (141b) and formed in a third direction different from the second direction, and The above plurality of reference regions (a1, a2, a3, a4) are, A first reference area (a1) where the first guide groove (141a) and the second guide groove (141b) meet; and A second reference area (a2) in which the second guide groove (141b) and the third guide groove (141c) meet, Robot system (1; 2; 3; 4).

5. In any one of paragraphs 1 through 4, The width of the at least one guide groove (141; 241; 341; 441) is such that it narrows as it moves toward the recessed direction of the at least one guide groove (141; 241; 341; 441). Robot system (1; 2; 3; 4).

6. In any one of paragraphs 1 through 5, The calibration jig (14; 14a; 14b; 14'; 24; 34; 44) interconnects the plurality of reference areas (a1, a2, a3, a4) and includes a guide groove (141; 241; 341; 441) in the shape of a closed loop formed by intaglio. Robot system (1; 2; 3; 4).

7. In any one of paragraphs 1 through 6, The above robot system (1; 2; 3; 4) is, It further includes a posture correction structure (15; 15a; 15b; 15') located between the plurality of reference regions (a1, a2, a3, a4), and The above calibration tool (123) is, It includes a correction structure coupling part (1232) that can be coupled to the posture correction structure (15; 15a; 15b; 15'), and The posture correction structure (15; 15a; 15b; 15') and the correction structure coupling part (1232), when fully coupled to each other, restrict the rotational movement in place of the calibration tool (123). Robot system (1; 2; 3; 4).

8. In any one of paragraphs 1 through 7, The posture correction structure (15; 15a; 15b; 15') is formed protruding from the calibration jig (14; 14a; 14b; 14'; 24; 34; 44), and The above correction structure coupling portion (1232) is formed by being recessed from the surface of the calibration tool (123). Robot system (1; 2; 3; 4).

9. In any one of paragraphs 1 through 8, The above calibration jig (14; 14a; 14b; 14'; 24; 34; 44) is, The calibration tool (123) further includes a plurality of guide grooves (141; 241; 341; 441) that are capable of two-point contact and are interconnected, and The posture correction structure (15; 15a; 15b; 15') is located inside the closed loop formed by the plurality of guide grooves (141; 241; 341; 441), Robot system (1; 2; 3; 4).

10. In any one of paragraphs 1 through 9, The above robot system (1; 2; 3; 4) is, An additional end effector (122) connected to the main body (11; 11') by a plurality of joints (121); It further includes an additional calibration tool (123) installed on the additional end effector (122) and having at least a portion formed in a spherical shape, and The calibration jig (14; 14a; 14b; 14'; 24; 34; 44) is positioned so as to be contactable by the additional calibration tool (123). Robot system (1; 2; 3; 4).

11. In any one of paragraphs 1 through 10, The center positions of the calibration tool (123) when the calibration tool (123) is in three-point contact with each of the plurality of reference areas (a1, a2, a3, a4) are placed on the same first plane (P1). Robot system (1; 2; 3; 4).

12. In any one of paragraphs 1 through 11, The above robot system (1; 2; 3; 4) is, The calibration tool (123) is positioned at a contactable location, and the calibration tool (123) is further positioned at a contactable location, and the calibration tool (123) is positioned at a contactable location, and the calibration tool (123) is positioned at a contactable location, and the calibration tool (123) is further4) is further positioned at a contactable location, and the calibration tool (123) is further positioned at a contactable location, and the calibration tool (14) is further positioned at a contactable location, and the calibration tool (123) is further positioned at The center positions of the calibration tool (123) when the calibration tool (123) is in three-point contact with each of the plurality of additional reference areas (a1, a2, a3, a4) are placed on the same second plane (P2), and Among the plurality of joints (121) connected to the end effector (122), the joint (121) located closest to the main body (11; 11') is connected to the main body (11; 11'), and based on the point where the first plane (P1) and the second plane (P2) are different. Robot system (1; 2; 3; 4).

13. A method for calibrating a robot system (1; 2; 3; 4) using a calibration jig (14; 14a; 14b; 14'; 24; 34; 44) comprising a plurality of reference areas (a1, a2, a3, a4) that can be three-point contacted by a calibration tool (123), wherein the method comprises: With the calibration tool (123) mounted on the end of the robot arm (12), the operation (921) of driving each joint (121) of the robot arm (12) with a design-based joint value determined through a design-based motion equation so that the calibration tool (123) approaches the first reference area (a1) among the plurality of reference areas (a1, a2, a3, a4); Operation (922, 923) of driving the robot arm (12) until the calibration tool (123) makes three-point contact with the first reference area (a1); An operation (924) of storing the actual joint values ​​of each joint (121) of the robot arm (12) while the calibration tool (123) is in three-point contact with the first reference area (a1); and The operation (927) of adjusting the position parameter of the equation of motion of the robot arm (12) based on the difference between the design-based joint value and the actual joint value, Calibration method for a robot system (1; 2; 3; 4).

14. In Paragraph 13, The operation (927) of adjusting parameters for the above position is performed based on the difference between the design-based joint value and the actual joint value for each of the plurality of reference areas (a1, a2, a3, a4), and The calibration jig (14; 14a; 14b; 14'; 24; 34; 44) further includes a guide groove (141; 241; 341; 441) that interconnects the first reference area (a1) and the second reference area (a2) among the plurality of reference areas (a1, a2, a3, a4). The above method is, The method further includes an operation (926) of driving the robot arm (12) so that the calibration tool (123) moves from the first reference area (a1) to the second reference area (a2) along the guide grooves (141; 241; 341; 441). Calibration method for a robot system (1; 2; 3; 4).

15. In Paragraph 13 or 14, The above robot system (1; 2; 3; 4) is, Attitude correction structures (15; 15a; 15b; 15') located between the plurality of reference regions (a1, a2, a3, a4); and In addition to the above robot arm (12), at least one additional robot arm (12) is included, The calibration tool (123) includes a calibration structure coupling part (1232) that can be coupled to the posture correction structure (15; 15a; 15b; 15'), and The above method is, An operation (931) of driving each joint (121) of the robot arm (12) with joint values ​​calculated through the parameter-adjusted motion equation, which is performed after the operation (927) of adjusting parameters for the above position, so that the correction structure coupling part (1232) approaches the posture correction structure (15; 15a; 15b; 15'); An operation (932, 933) of driving the robot arm (12) until the above correction structure coupling part (1232) is coupled to the posture correction structure (15; 15a; 15b; 15'); An operation (933) of storing the actual joint values ​​of each joint (121) of the robot arm (12) while the above correction structure coupling part (1232) is coupled to the posture correction structure (15; 15a; 15b; 15'); An action (934) of adjusting the parameters for the posture of the equation of motion of the robot arm (12) based on the difference between the calculated joint value and the actual joint value; An operation (94) of correcting the origin of the coordinate system of the robot arm (12) to the position of the posture correction structure (15; 15a; 15b; 15'); With the calibration tool (123) mounted on the end of the additional robot arm (12), the operation (92) of adjusting the position parameters of the equation of motion of the additional robot arm (12) using the calibration jig (14; 14a; 14b; 14'; 24; 34; 44); An operation (93) of adjusting parameters for the posture of the equation of motion of the additional robot arm (12) using the posture correction structure (15; 15a; 15b; 15') while the calibration tool (123) is mounted on the end of the additional robot arm (12); and Further including an operation (94) of correcting the origin of the coordinate system of the additional robot arm (12) to the position of the attitude correction structure (15; 15a; 15b; 15'). Calibration method for a robot system (1; 2; 3; 4).

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