Robot system and control device

Abstract

This robot system includes: a robot; a camera; a moving unit that moves the robot; an imaging unit that, while the robot is moving, causes the camera to capture an image of a feature unit at least once; and a trajectory error calculation unit that calculates a trajectory error of the robot on the basis of the feature unit captured in the image and a prescribed point in the image.

Description

Robot system and control device

[0001] The present disclosure relates to a robotic system and a control device.

[0002] When a robot is made to perform a task, a motion path of the robot is set by teaching the robot a plurality of teaching points in advance. In applications such as arc welding and sealing, a large number of teaching points are set on the robot's motion path. Patent Document 1 discloses that, in order to improve the accuracy of the robot's trajectory, a deviation amount between the robot's actual movement trajectory and the robot's reference trajectory defined by a movement command is acquired.

[0003] Patent Publication No. 2021-013983

[0004] However, the robot's trajectory between two adjacent teaching points is not always clear. Therefore, when setting the robot's motion path, the operator cannot determine how many teaching points should be set. Although teaching a large number of teaching points improves the accuracy of the robot's trajectory, it also increases the number of teaching operations, which takes time.

[0005] Therefore, there is a need for a robot system and a control device that can confirm the trajectory accuracy of the robot in order to teach an appropriate number of teaching points.

[0006] According to a first aspect of the present disclosure, there is provided a robot system comprising: a robot; a camera; a moving unit that moves the robot; an imaging unit that captures an image of a characteristic part with the camera at least once while the robot is being moved by the moving unit; and a trajectory error calculation unit that calculates a trajectory error of the robot based on the captured characteristic part in the image and a predetermined point in the image.

[0007] Furthermore, according to another aspect of the present disclosure, there is provided a control device including: a moving unit that moves a robot; an imaging unit that captures an image of a characteristic part at least once with a camera while the robot is being moved by the moving unit; and a trajectory error calculation unit that calculates a trajectory error of the robot based on the captured characteristic part in the image and a predetermined point in the image.

[0008] The objects, features, and advantages of the present disclosure will become more apparent from the following description of the embodiments taken in conjunction with the accompanying drawings.

[0009] FIG. 1B is a schematic diagram of a robot system based on a first embodiment; FIG. 1C is a flowchart showing the operation of the robot system shown in FIG. 1A; FIG. 1D is a top view of an object having a feature; FIG. 1E is a perspective view for explaining the operation of the robot system in the first embodiment; FIG. 1F is a diagram showing an image from a camera; FIG. 1G is a diagram showing the relationship between the moving distance of the robot and the trajectory error; FIG. 1H is a flowchart showing another operation of the robot system; FIG. 1I is a perspective view for explaining the operation of the robot system in the second embodiment; FIG. 1J is a diagram showing another image from a camera; FIG. 1I is a perspective view for explaining the operation of the robot system in the third embodiment; FIG. 1J is a diagram showing the relationship between the distance between the camera and the feature and the trajectory error; FIG. 1I is a schematic diagram of a robot system based on another embodiment.

[0010] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. Corresponding components throughout the drawings are designated by common reference numerals. FIG. 1A is a schematic diagram of a robot system according to a first embodiment. As shown in FIG. 1A, a robot system 1a according to the first embodiment mainly includes a robot 10, a control device 20 that controls the robot 10, and a teaching pendant 30 that operates the robot 10 via the control device 20. However, if an operator operates the robot 10 via the control device 20, the robot system 1a (and a robot system 1b described below) may not include the teaching pendant 30. Note that the robot 10 and the control device 20, and the control device 20 and the teaching pendant 30, are connected via wire or wirelessly.

[0011] The robot 10 may be, for example, a vertical articulated robot with six degrees of freedom and equipped with multiple motors. In the robot 10 shown in Fig. 1A, multiple arms 12, each driven by a corresponding one of the multiple motors, are arranged on a robot base 11 in a known manner. The most distal arm is equipped with a wrist 13.

[0012] Although not shown in the drawings, each of the multiple motors is provided with a detection unit, such as an encoder, that detects the position and / or speed of the corresponding shaft. Similarly, although not shown in the drawings, each of the multiple motors may be provided with various sensors, such as a temperature sensor.

[0013] A rod 14 is attached to the wrist 13 of the robot 10, and a camera 15 is provided at the tip of the rod 14. In the first embodiment, the camera 15 is, for example, a 2D camera. Note that the camera 15 may be attached directly to the wrist 13 without using the rod 14.

[0014] As shown in Fig. 1A, an object 45 installed at a fixed position is placed below the camera 15. In Fig. 1A, the object 45 is a plate placed on a table. However, the object 45 may be the table top itself. The object 45 may also be placed directly on the floor.

[0015] The object 45 has a characteristic portion 51 that corresponds to the target trajectory of the robot 10. FIG. 2 is a top view of the object having the characteristic portion. In the first embodiment, the characteristic portion 51 is a straight line drawn on the top surface of the object 45. The length L0 and width of the characteristic portion 51 are known and are stored in a memory unit 29 (described later) of the control device 20. Note that the characteristic portion 51 may have other visually recognizable configurations. For example, the characteristic portion 51 may be a recess, notch, protrusion, ridge, or the like formed on the top surface of the object 45. Note that, as will be described later, the characteristic portion 51 does not have to be a straight line as long as its shape is known.

[0016] The robot 10 is controlled by a control device 20. As is well known, the control device 20 controls multiple motors using detection results from multiple detection units. The control device 20 is a computer including a CPU (Central Processing Unit), a storage unit 29, and the like, which are connected to each other via a bus.

[0017] The storage unit 29 may be a volatile memory, a non-volatile memory, a hard disk drive, or a solid state drive. The storage unit 29 stores various data and an operation program (described later) for operating the robot 10. The control device 20 also controls the image capture by the camera 15 and performs image processing on the images captured by the camera 15.

[0018] As shown in FIG. 1A , the CPU of the control device 20 includes a moving unit 21 that moves the robot 10, an imaging unit 22 that takes an image 16 of the characteristic portion 51 at least once using the camera 15 while the robot 10 is being moved by the moving unit 21, and a trajectory error calculation unit 23 that calculates a trajectory error ΔT of the robot 10 based on the captured characteristic portion 51 in the image 16 and a predetermined point P0 in the image 16.

[0019] Furthermore, the CPU of the control device 20 further includes a graph creation unit 24 that creates a relationship between the movement distance L of the robot 10 and the trajectory error ΔT when the imaging unit 22 causes the camera 15 to capture an image 16 multiple times, and an additional instruction unit 25 that instructs the robot 10 to add a teaching point if the trajectory error ΔT is greater than a predetermined threshold value ΔT0.

[0020] The teaching pendant 30 is also a computer and similarly includes a CPU, memory, etc. The teaching pendant 30 includes a display unit 31, such as a display, that displays various processes of the control device 20 and the teaching pendant 30. Furthermore, the teaching pendant 30 includes an input unit 32, such as a touch panel, that inputs various operations by the operator.

[0021] Instead of the CPU of the control device 20, the CPU of the teaching pendant 30 may have the movement unit 21, the imaging unit 22, the trajectory error calculation unit 23, the graph creation unit 24, and the additional instruction unit 25. Alternatively, the CPU of the control device 20 may have at least one of the movement unit 21, the imaging unit 22, the trajectory error calculation unit 23, the graph creation unit 24, and the additional instruction unit 25, and the CPU of the teaching pendant 30 may have the remaining of the movement unit 21, the imaging unit 22, the trajectory error calculation unit 23, the graph creation unit 24, and the additional instruction unit 25.

[0022] The moving unit 21, the imaging unit 22, the trajectory error calculation unit 23, the graph creation unit 24, and the additional instruction unit 25 possessed by the CPU of the control device 20 and / or the teaching pendant 30 are functional modules realized by, for example, a computer program executed on the CPU. The computer program for executing the processes of the moving unit 21, the imaging unit 22, the trajectory error calculation unit 23, the graph creation unit 24, and the additional instruction unit 25 possessed by the CPU of the control device 20 and / or the teaching pendant 30 may be provided in a form recorded on a computer-readable recording medium such as a semiconductor memory, a magnetic recording medium, or an optical recording medium.

[0023] The control device 20 may also be connected to a display unit, such as a display, CRT, etc., that displays various computer processes. Furthermore, the control device 20 may also be connected to an input unit, such as a mouse and keyboard, that inputs various operations by the operator.

[0024] 1B is a flowchart showing the operation of the robot system shown in FIG. 1A. The operation of the robot system 1a will be described below with reference to FIG. 1B. It is assumed that two teaching points are taught in the operation program for the robot 10. One teaching point is one end 41 of the characteristic portion 51, which serves as the start position for the operation of the robot 10, and the other teaching point is the other end 42 of the characteristic portion 51, which serves as the end position for the operation of the robot 10. Therefore, these teaching points may be referred to as teaching points 41 and 42, respectively.

[0025] One teaching point 41 is taught so that a predetermined point P0 of the image 16 to be captured by the camera 15 coincides with one end 41 of the characteristic portion 51. Similarly, the other teaching point 42 is taught so that a predetermined point P0 of the image 16 to be captured by the camera 15 coincides with the other end 42 of the characteristic portion 51. Such an operation program is stored in the storage unit 29. Furthermore, the camera 15 is positioned in advance so that at least a portion of the characteristic portion 51 is within the field of view of the camera 15.

[0026] 1B , the operator sets the total number of times N to capture images (N is a natural number) using the input unit 32. Next, in step S12, the movement unit 21 moves the robot 10 based on the created operation program. That is, the movement unit 21 moves the wrist 13 of the robot 10 linearly along the characteristic portion 51. Note that the movement speed of the robot 10 is determined based on the overall length L0 of the characteristic portion 51 and the total number of times N to capture images, so that the camera completes N images at regular time intervals while the robot 10 moves from one end 41 to the other end 42 of the characteristic portion 51.

[0027] 3 is a perspective view for explaining the operation of the robot system according to the first embodiment, which shows a characteristic portion 51 corresponding to a target trajectory of the robot 10 and an actual trajectory 52 along which the robot 10 actually moves.

[0028] In step S13, while the robot 10 is moving, the imaging unit 22 causes the camera 15 to capture the first image (i-th image, where i is the current number of times that the image is captured and is a natural number equal to or less than the total number of times that the image is captured N) of the characteristic portion 51. The captured image 16 is stored in the storage unit 29. The movement unit 21 also calculates the movement distance L1 (movement distance Li) from one end 41 of the characteristic portion 51 of the robot 10 when the image is captured by the camera 15. The movement distance Li may be calculated from the detection results of multiple detection units provided on each of the multiple motors, or may be calculated from the elapsed time since the robot 10 moved and the movement speed of the robot 10. The movement distance Li is stored in the storage unit 29 in association with the corresponding i-th image 16.

[0029] Next, in step S14, it is confirmed whether the current number of times i to capture images is the same as the total number of times N to capture images. If the current number of times i to capture images is different from the total number of times N to capture images, the process proceeds to step S15, where "1" is added to the current number of times i to capture images, and the process proceeds to step S13. Then, in step S13, the second (ith (←i+1)) image of the characteristic portion 51 is taken and the travel distance Li is calculated in the same way, and these are associated and stored in the storage unit 29. The process is then repeated until the current number of times i to capture images is the same as the total number of times N to capture images. When the current number of times i to capture images is the same as the total number of times N to capture images, the process proceeds to step S16, where the movement unit 21 stops the robot 10 at the other end 42 of the characteristic portion 51.

[0030] Next, in step S17, the trajectory error calculation unit 23 calculates the trajectory error ΔT1 (trajectory error ΔTi) for the first (i-th) time. FIG. 4 is a diagram showing an image captured by the camera. Strictly speaking, the image 16 shown in FIG. 4 is the i-th image captured after the first time, and therefore one end 41 of the feature portion 51 is not shown in the image 16 in FIG. 4. In FIG. 4, the predetermined point P0 is the center of the image 16. However, the predetermined point P0 may be set at another location within the image 16.

[0031] 4, the trajectory error calculation unit 23 draws a perpendicular line from the predetermined point P0 to the characteristic feature 51 in the ith image 16 and calculates the length of this perpendicular line as the trajectory error ΔTi. The trajectory error ΔTi is associated with the corresponding image 16 and the movement distance Li and stored in the storage unit 29. Note that the trajectory error ΔTi is assigned a plus or minus sign depending on the positional relationship between the predetermined point P0 and the characteristic feature 51. Furthermore, since the first image 16 is captured when the robot 10 starts moving or immediately after starting to move, the trajectory error ΔT1 in the first image 16 is approximately zero.

[0032] Next, in step S18, it is confirmed whether the current number of times i of imaging is the same as the total number of times N of imaging. If the current number of times i of imaging is different from the total number of times N of imaging, the process proceeds to step S19, where "1" is added to the current number of times i of imaging, and the process proceeds to step S17. Then, in step S17, the trajectory error ΔTi is similarly calculated from the image 16 obtained in the second imaging (i-th (←i+1)-th) imaging, and similarly stored in the storage unit 29. The process is then repeated until the current number of times i of imaging is the same as the total number of times N of imaging.

[0033] In this way, the trajectory error calculation unit 23 calculates the trajectory error ΔTi, allowing the operator to easily grasp the trajectory error ΔTi of the robot 10. This allows the operator to independently determine whether each trajectory error ΔTi is large or not, for example.

[0034] In the present disclosure, a visually recognizable feature 51 is captured by a camera 15, and the trajectory error ΔTi is calculated based on the positional relationship between the feature 51 and a predetermined point P0 in the image 16. The feature 51 corresponds to the target trajectory of the robot 10, and the predetermined point P0 corresponds to the actual trajectory 52. ​​In other words, in the present disclosure, the target trajectory and the actual trajectory 52 coexist in a single image 16, and therefore the trajectory error ΔTi can be calculated directly. Therefore, in the present disclosure, the trajectory error ΔTi can be calculated more accurately than when calculating the error between a target trajectory created from a movement command for the robot 10 and an actual trajectory created by a camera.

[0035] Next, in step S20, the graph creation unit 24 creates a graph based on the relationship between the travel distance Li and the trajectory error ΔTi of the robot 10 stored in the memory unit 29. FIG. 5A is a diagram showing the relationship between the travel distance Li of the robot 10 and the trajectory error. In FIG. 5A, the horizontal axis represents the travel distance Li of the robot 10, which corresponds to the characteristic portion 51. The vertical axis represents the trajectory error ΔTi, and the dashed line 52 corresponds to the actual trajectory 52. ​​Therefore, in other words, the graph creation unit 24 creates a graph of the actual trajectory 52. ​​It will be apparent to those skilled in the art that the greater the total number of times N of imaging, the more precise the actual trajectory 52 that can be created.

[0036] In this way, the graph creation unit 24 creates a graph of the actual trajectory 52, allowing the operator to visually determine the behavior of the trajectory error ΔTi along the characteristic portion 51. Therefore, it is possible to easily find defects in the actual operation of the robot 10, such as an increase in the trajectory error ΔTi near a specific point on the characteristic portion 51.

[0037] As described above, the one end 41 and the other end 42 of the characteristic portion 51 correspond to teaching points of the robot 10. That is, in Fig. 5A and other figures, the behavior of the robot 10 between two adjacent teaching points 41 and 42 is represented as an actual trajectory 52. ​​If the trajectory error ΔTi between the teaching points 41 and 42 is large, it is preferable to set an additional teaching point Q between the teaching points 41 and 42.

[0038] Here, Fig. 5B is a flowchart showing another operation of the robot system. The flowchart shown in Fig. 5B is executed appropriately after the flowchart shown in Fig. 1B is completed.

[0039] In step S21, the additional instruction unit 25 determines whether the absolute value |ΔTi| of the trajectory error ΔTi is greater than a predetermined value ΔT0. The predetermined value ΔT0 is a value obtained through an experiment or a simulation. If the absolute value |ΔTi| of the trajectory error ΔTi is greater than the predetermined value ΔT0, the additional instruction unit 25 instructs to additionally teach a teaching point Q on or near the corresponding moving distance Li.

[0040] Then, in step S23, it is confirmed whether the current number of times i to capture images is the same as the total number of times N to capture images. If the current number of times i to capture images is different from the total number of times N to capture images, the process proceeds to step S124, where "1" is added to the current number of times i to capture images, and the process proceeds to step S21. Then, in step S21, the absolute value |ΔTi| of the next trajectory error ΔTi (i←i+1) is compared with the predetermined value ΔT0 in the same manner. The process is repeated until the current number of times i to capture images is the same as the total number of times N to capture images.

[0041] 5A shows an additional teaching point Q on the movement distance Li corresponding to the trajectory error ΔTi larger than a predetermined value ΔT0. Therefore, the operator can actually add the additional teaching point Q in accordance with the instruction of the addition instruction unit 25. It will be understood that when the additional teaching point Q is added, the trajectory error ΔTi in the vicinity of the additional teaching point Q can be significantly reduced. Note that the addition instruction unit 25 may also instruct to teach a plurality of additional teaching points in the vicinity of the movement distance Li.

[0042] FIG. 6A is a perspective view illustrating the operation of the robot system in the second embodiment. In the second embodiment, a characteristic portion 51' of the object 45 is a circle with a known diameter. In this case, the operation program of the robot 10 teaches only a point 41 located on the circumference of the circle as a single teaching point 41. Strictly speaking, this teaching point 41 is taught so that a predetermined point P0 in an image 16 to be captured by the camera 15 coincides with the point 41 located on the circumference of the circle. FIG. 6A also shows an actual trajectory 52'.

[0043] 6B is a diagram showing another image captured by the camera. As shown in FIG. 6B, the trajectory error calculation unit 23 draws a perpendicular line from a predetermined point P0 in the image 16 captured by the camera 15 to a tangent (indicated by a dashed line) to the characteristic portion 51′, and obtains the length of the perpendicular line as the trajectory error ΔTi. The travel distance Li may be calculated from the detection results of multiple detectors provided on each of the multiple motors, or may be calculated from the elapsed time since the robot 10 began to move, the travel speed of the robot 10, and the diameter of a circle representing the characteristic portion 51′. The characteristic portion 51′ may be a known ellipse or a known curve. Furthermore, the characteristic portion 51′ may at least partially include such a known curve.

[0044] Fig. 7A is a perspective view illustrating the operation of the robot system in the third embodiment. The camera 15 in Fig. 7A is a camera, such as a 3D camera, that can measure the distance Z between the camera 15 and a subject (corresponding to the image 16 in Fig. 7A).

[0045] In this case, the camera 15 determines the three-dimensional positions of one end 41 and the other end 42 of the characteristic portion 51, i.e., the three-dimensional positions of the teaching points 41, 42. The movement unit 21 then determines the three-dimensional function of the characteristic portion 51 using a known method. Thereafter, an operation program is created so that the robot 10 moves linearly parallel to the characteristic portion 51 from one end 41 to the other end 42 of the characteristic portion 51, and the program is stored in the storage unit 29. The distance between the camera 15 and the one end 41 of the characteristic portion 51, detected by imaging, is stored in the storage unit 29 as distance Z0.

[0046] 1A, the movement unit 21 moves the robot 10 according to the operation program, and the imaging unit 22 captures images N times at regular time intervals while the robot 10 is moving. Then, in step S13, in addition to capturing the i-th image and calculating the movement distance Li, the distance Zi between the camera 15 and the characteristic feature 51 at the time of capturing the i-th image is also obtained.

[0047] In step S17, the additional trajectory error ΔTi' is calculated as |Zi-Z0|. In the third embodiment, the additional trajectory error ΔTi' is not calculated directly from the image 16. Therefore, in the third embodiment, it is not necessary to use the camera 15 as a 3D camera, and a distance sensor may be used instead of the camera 15. Alternatively, in the third embodiment, the camera 15 as a 2D camera and a distance sensor may be used in combination.

[0048] Furthermore, in step S20, the graph creation unit 24 displays a graph of the relationship between the distance Zi and the additional trajectory error ΔTi' of the robot 10, in addition to the relationship between the travel distance Li and the trajectory error ΔTi stored in the memory unit 29. FIG. 7B is a diagram showing the relationship between the distance between the camera and the characteristic feature and the trajectory error. As shown in FIG. 7B, a graph can be created with the travel distance Li on the horizontal axis and the additional trajectory error ΔTi' on the vertical axis. In this case, the trajectory error ΔTi and the additional trajectory error ΔTi' are calculated, making it possible to grasp the difference between the target trajectory and the actual trajectory in three dimensions.

[0049] Furthermore, in the third embodiment, as described with reference to Fig. 5B, when the absolute value |ΔTi'| of the additional trajectory error ΔTi' is larger than a predetermined value ΔT0', the additional instruction unit 25 instructs to additionally teach a teaching point Q' on or near the corresponding moving distance Li. It will be understood that in this case as well, the same effect as described above can be obtained.

[0050] Fig. 8 is a schematic diagram of a robot system according to another embodiment. In the robot system 1b shown in Fig. 8, an openable and closable hand 14' is provided on the wrist 13. The hand 14' grasps an object 45 similar to that described above. The hand 14' may be opened and closed by one of the multiple motors of the robot 10.

[0051] Furthermore, the camera 15 is not provided on the robot 10, but is fixed independently of the robot 10. The object 45 is positioned in advance so that the image 16 to be captured by the camera 15 includes one end 41 of the characteristic portion 51. It is clear that with this configuration as well, the same effect as described above can be obtained.

[0052] As an effect of at least one of the embodiments described above, the trajectory accuracy of the robot can be easily confirmed. Furthermore, by teaching additional teaching points at locations where the trajectory accuracy is low, an appropriate number of teaching points can be taught.

[0053] Although the embodiments of the present disclosure have been described in detail, the present disclosure is not limited to the individual embodiments described above. Various additions, substitutions, modifications, partial deletions, etc. are possible to these embodiments without departing from the gist of the invention or the concept and spirit of the present invention derived from the content of the claims and their equivalents. For example, in the above-described embodiments, the order of each operation and the order of each process are shown as examples and are not limited to these. The same applies when numerical values ​​or mathematical formulas are used in the description of the above-described embodiments. Furthermore, appropriate combinations of several of the above-described embodiments are within the scope of the present disclosure.

[0054] The following supplementary notes are further disclosed regarding the above embodiments and variations. (Supplementary Note 1) A robot system comprising: a robot; a camera; a moving unit that moves the robot; an imaging unit that captures an image of a characteristic part with the camera at least once while the robot is being moved by the moving unit; and a trajectory error calculation unit that calculates a trajectory error of the robot based on the characteristic part captured in the image and a predetermined point in the image. (Supplementary Note 2) The robot system according to Supplementary Note 1, wherein the camera is provided on the robot and an object including the characteristic part is disposed at a fixed position, or the camera is disposed at a fixed position and the object is provided on the robot. (Supplementary Note 3) The robot system according to Supplementary Note 1 or 2, wherein the moving unit moves the robot so that the characteristic part in the image coincides with the predetermined point. (Supplementary Note 4) The robot system according to any of Supplements 1 to 3, wherein the characteristic part includes at least one of a straight line of a predetermined shape and a curved line of a predetermined shape. (Supplementary Note 5) The robot system according to Supplementary Note 4, wherein, when the characteristic portion includes the straight line, the trajectory error calculation unit calculates the length of a perpendicular line extending from the predetermined point to the straight line as the trajectory error. (Supplementary Note 6) The robot system according to Supplementary Note 4, wherein, when the characteristic portion includes the curved line, the trajectory error calculation unit calculates the length of a line segment extending from the predetermined point to a tangent to the curve as the trajectory error. (Supplementary Note 7) The robot system according to any one of Supplements 1 to 6, further comprising a graph creation unit that creates a relationship between a moving distance of the robot and the trajectory error when the imaging unit captures the image multiple times. (Supplementary Note 8) The robot system according to any one of Supplements 1 to 7, further comprising an addition instruction unit that instructs the robot to add a teaching point when the trajectory error is greater than a predetermined threshold. (Supplementary Note 9) The robot system according to any one of Supplementary Notes 1 to 8, wherein the camera is a 3D camera that measures a distance between the camera and the object, and the trajectory error calculation unit calculates an additional trajectory error based on the distance and a predetermined distance between the 3D camera and the characteristic part.(Supplementary Note 10) A control device comprising: a moving unit that moves a robot; an imaging unit that captures an image of a characteristic part by a camera at least once while the robot is being moved by the moving unit; and a trajectory error calculation unit that calculates a trajectory error of the robot based on the characteristic part captured in the image and a predetermined point in the image. (Supplementary Note 11) The control device according to Supplementary Note 10, wherein the camera is provided on the robot and an object including the characteristic part is disposed at a fixed position, or the camera is disposed at a fixed position and the object is provided on the robot. (Supplementary Note 12) The control device according to Supplementary Note 10 or 11, wherein the moving unit moves the robot so that the characteristic part in the image coincides with the predetermined point. (Supplementary Note 13) The control device according to any of Supplements 10 to 12, wherein the characteristic part includes at least one of a straight line of a predetermined shape and a curved line of a predetermined shape. (Supplementary Note 14) The control device according to Supplementary Note 13, wherein, when the characteristic portion includes the straight line, the trajectory error calculation unit calculates the length of a perpendicular line extending from the predetermined point to the straight line as the trajectory error. (Supplementary Note 15) The control device according to Supplementary Note 13, wherein, when the characteristic portion includes the curved line, the trajectory error calculation unit calculates the length of a line segment extending from the predetermined point to a tangent to the curve as the trajectory error. (Supplementary Note 16) The control device according to any of Supplements 10 to 15, further comprising a graph creation unit that creates a relationship between a moving distance of the robot and the trajectory error when the imaging unit captures the image multiple times. (Supplementary Note 17) The control device according to any of Supplements 10 to 16, further comprising an addition instruction unit that instructs the robot to add a teaching point when the trajectory error is greater than a predetermined threshold. (Supplementary Note 18) The control device according to any one of Supplementary Notes 10 to 17, wherein the camera is a 3D camera that measures a distance between the camera and the object, and the trajectory error calculation unit calculates an additional trajectory error based on the distance and a predetermined distance between the 3D camera and the characteristic feature.

[0055] 1a, 1b Robot system 10 Robot 11 Robot base 12 Arm 13 Wrist 14 Bar 14' Hand 15 Camera 16 Image 20 Control device 21 Moving unit 22 Imaging unit 23 Trajectory error calculation unit 24 Graph creation unit 25 Additional instruction unit 29 Memory unit 30 Teaching operation panel 31 Display unit 32 Input unit 41 One end 42 Other end 45 Object 51, 51' Feature unit 52, 52' Actual trajectory

Claims

1. A robot system comprising: a robot; a camera; a moving unit that moves the robot; an imaging unit that captures an image of a characteristic part with the camera at least once while the robot is moved by the moving unit; and a trajectory error calculation unit that calculates a trajectory error of the robot based on the characteristic part captured in the image and a predetermined point in the image.

2. The robot system of claim 1, wherein the camera is mounted on the robot and an object including the feature is located at a fixed position, or the camera is located at a fixed position and the object is mounted on the robot.

3. The robot system according to claim 1, wherein the movement unit moves the robot so that the characteristic portion in the image coincides with the predetermined point.

4. The robot system of claim 1, wherein the feature portion includes at least one of a straight line having a predetermined shape and a curved line having a predetermined shape.

5. A robot system according to claim 4, wherein, when the characteristic portion includes the straight line, the trajectory error calculation unit calculates the length of a perpendicular line extending from the specified point to the straight line as the trajectory error.

6. A robot system as described in claim 4, wherein, when the characteristic portion includes the curve, the trajectory error calculation portion calculates the length of a line segment extending from the specified point to a tangent to the curve as the trajectory error.

7. The robot system according to claim 1, further comprising a graph creation section that creates a relationship between the moving distance of the robot and the trajectory error when the imaging section captures the image a plurality of times.

8. The robot system according to claim 1, further comprising an addition instruction unit that instructs the robot to add a teaching point when the trajectory error is greater than a predetermined threshold value.

9. The robot system of claim 1, wherein the camera is a 3D camera that measures the distance between the camera and the object, and the trajectory error calculation unit calculates an additional trajectory error based on the distance and a predetermined distance between the 3D camera and the characteristic portion.

10. A control device comprising: a moving unit that moves a robot; an imaging unit that captures an image of a characteristic part at least once with a camera while the robot is being moved by the moving unit; and a trajectory error calculation unit that calculates a trajectory error of the robot based on the characteristic part captured in the image and a predetermined point in the image.

11. The control device of claim 10, wherein the camera is mounted on the robot and an object including the feature is located at a fixed position, or the camera is located at a fixed position and the object is mounted on the robot.

12. The control device according to claim 10, wherein the movement unit moves the robot so that the characteristic portion in the image coincides with the predetermined point.

13. The control device of claim 10, wherein the feature includes at least one of a straight line of a predetermined shape and a curve of a predetermined shape.

14. The control device according to claim 13, wherein, when the characteristic portion includes the straight line, the trajectory error calculation portion calculates the length of a perpendicular line extending from the predetermined point to the straight line as the trajectory error.

15. The control device according to claim 13, wherein, when the characteristic portion includes the curve, the trajectory error calculation portion calculates the length of a line segment extending from the specified point to a tangent to the curve as the trajectory error.

16. The control device according to claim 10, further comprising a graph creation unit that creates a relationship between the moving distance of the robot and the trajectory error when the imaging unit captures the image a plurality of times.

17. The control device according to claim 10, further comprising an addition instruction unit that instructs the robot to add a teaching point when the trajectory error is greater than a predetermined threshold value.

18. The control device according to claim 10, wherein the camera is a 3D camera that measures the distance between the camera and the object, and the trajectory error calculation unit calculates an additional trajectory error based on the distance and a predetermined distance between the 3D camera and the characteristic feature.

Images