Work device and work method

Abstract

This work device performs work by controlling the position and angle of an end effector with respect to a workpiece. The work device is provided with: a vector A setting means (73a) for setting, from teaching data (72a), a vector (A) that represents a direction and a magnitude on a work path on a surface of the workpiece; and a vector B setting means (73b) for setting, from the teaching data (72a), a vector (B) that includes a direction, a magnitude, and a rotation amount for the work performed by the end effector. The work device is further provided with: an inner product value calculation means (74a) for calculating an inner product value of the vectors (A, B); a rotation amount determination means (74b) for determining a rotation amount of the vector (B) that maximizes the inner product value calculated by the inner product value calculation means (74a); and a teaching data reflection means (74c) for reflecting the rotation amount of the vector (B) determined by the rotation amount determination means (74b) in the teaching data (72a).

Description

Work apparatus and work method Related applications

[0001] This application claims priority to Japanese Patent Application No. 2025-051379, filed on 26 March 2025, which is incorporated herein by reference as forming part of this application.

[0002] The present invention relates to a work device and a work method, and more particularly to a technology that can be used in equipment requiring high speed, high precision, a wide operating range, and fine movements, such as medical equipment or industrial equipment, and that can reduce the man-hours required of the operator.

[0003] A work device that performs work on a workpiece using an end effector is known (for example, Patent Document 1). Patent Document 1 discloses a technique for inspecting an article, which is the workpiece, using a robot. In some cases, the robot may perform movements that trace the surface of the workpiece under its programming. In such cases, for example, when the end effector Ee, such as a cutter knife, has a working orientation, as shown in Figure 21A, it is necessary to adjust the twist angle β of the end effector Ee around the working axis Ca as appropriate, as shown in Figure 21B. Conventionally, the twist angle β of the end effector Ee was adjusted based on the operator's experience.

[0004] Japanese Patent Publication No. 2017-26441

[0005] When the end effector Ee is traced along a two-dimensional plane or in one direction, the twist angle β of the end effector Ee can be easily determined. However, when the workpiece is a three-dimensional curved surface or when the movement traces a complex path, determining the twist angle β of the end effector Ee becomes difficult for the operator.

[0006] The objective of the present invention is to provide a work apparatus and work method that can reduce the man-hours required of the worker.

[0007] The present invention will be described below with reference to the reference numerals of embodiments for convenience, in order to facilitate understanding.

[0008] The work device 1 of the present invention is a work device that performs work by controlling the position and angle of an end effector Ee on a workpiece 2, and comprises: a vector A setting means 73a that sets a vector A which is the orientation and magnitude of the work path RT on the surface of the workpiece 2 from teaching data 72a; a vector B setting means 73b that sets a vector B which includes the orientation, magnitude and amount of rotation of the end effector Ee performing the work from the teaching data 72a; a dot product value calculation means 74a that calculates the dot product value of vectors A and B; a rotation amount determination means 74b that determines the amount of rotation of vector B that maximizes the dot product value calculated by the dot product value calculation means 74a; and a teaching data reflection means 74c that reflects the amount of rotation of vector B determined by the rotation amount determination means 74b to the teaching data 72a.

[0009] With this configuration, the amount of rotation of the end effector Ee is automatically calculated so that the dot product of vectors A and B calculated by the dot product calculation means 74a is maximized. This reduces the amount of work required from the operator compared to conventional techniques that rely on the operator's experience to adjust the twist angle of the end effector. Therefore, it becomes possible to control the position and angle of the end effector Ee with high precision and fine detail relative to the workpiece 2. Even when the workpiece 2 is a three-dimensional curved surface or when it moves along a complex path to trace the object, it is possible to control the position and angle of the end effector Ee with high precision and fine detail relative to the workpiece 2 while reducing the amount of work required from the operator.

[0010] The system may also include a linear motion mechanism 63 having linear actuators 65, 66, and 67 whose directions of movement are mutually orthogonal, and a rotary mechanism Ra having a rotary actuator 18 that rotates the end effector Ee or the workpiece 2.

[0011] In this case, the relative position and angle of the end effector Ee with respect to the workpiece 2 can be freely changed, making it possible to perform work on workpieces 2 of various shapes and sizes.

[0012] The tip member 40 may be equipped with a link actuation device 7 that supports the end effector Ee or the workpiece 2. In this case, because the link actuation device 7 is provided, the position and angle of the end effector Ee can be controlled smoothly and at high speed without singularities, compared to a typical vertical articulated robot. The term "singularity" refers to a posture that cannot be controlled structurally. In a typical vertical articulated robot, a singularity refers to a posture in which multiple arms are aligned in a straight line, etc.

[0013] The link actuator 7 is configured such that the tip-side link hub 13 is connected to the base-side link hub 12 via three or more link mechanisms 14 so as to be able to change its orientation. Each link mechanism 14 has, respectively, a base-side and tip-side end link member 15, 16 with one end rotatably connected to the base-side link hub 12 and the tip-side link hub 13, and a central link member 17 with both ends rotatably connected to the other ends of these base-side and tip-side end link member 15, 16. Two or more of the three or more link mechanisms 14 may be equipped with an orientation control actuator 10 for arbitrarily controlling the orientation of the tip-side link hub 13.

[0014] In this case, the link hub 13 at the tip can be moved linearly to the desired position, thus shortening the cycle time compared to configurations such as those of typical vertical articulated robots. Furthermore, cables and other wiring can be passed through the internal space of the link actuator 7, and the wiring will not twist even when rotational movements are repeated, making wiring management easier.

[0015] The present invention provides a work method for controlling the position and angle of an end effector Ee relative to a workpiece 2, comprising: a vector A setting process S1 for setting a vector A which is the orientation and magnitude of the work path RT on the surface of the workpiece 2 from teaching data 72a; a vector B setting process S2 for setting a vector B which includes the orientation, magnitude and amount of rotation of the end effector Ee performing the work from the teaching data 72a; a dot product calculation process S3 for calculating the dot product value of vectors A and B; a rotation amount determination process S4 for determining the amount of rotation of vector B that maximizes the dot product value calculated in the dot product calculation process S3; and a teaching data reflection process S5 for reflecting the amount of rotation of vector B determined in the rotation amount determination process S4 back into the teaching data 72a.

[0016] According to this work method, the amount of rotation of the end effector Ee is automatically calculated so that the dot product of vectors A and B calculated in the dot product calculation process S3 is maximized. This reduces the amount of work required from the operator compared to conventional techniques that rely on the operator's experience to adjust the twist angle of the end effector. Therefore, it becomes possible to control the position and angle of the end effector Ee with high precision and fine detail relative to the workpiece 2. Even when the workpiece 2 is a three-dimensional curved surface or when it moves along a complex path to trace the object, it is possible to control the position and angle of the end effector Ee with high precision and fine detail relative to the workpiece 2 while reducing the amount of work required from the operator.

[0017] Any combination of at least two configurations disclosed in the claims and / or the specification and / or drawings is included in the present invention. In particular, any combination of two or more of each claim is included in the present invention.

[0018] The present invention will be more clearly understood from the following description of preferred embodiments with reference to the accompanying drawings. However, the embodiments and drawings are for illustrative and explanatory purposes only and should not be used to define the scope of the invention. The scope of the invention is defined by the accompanying claims. In the accompanying drawings, the same reference numerals in multiple drawings indicate the same or corresponding parts.

[0019] This is a front view of a work device according to the first embodiment of the present invention. This is a conceptual perspective view showing an example of the device configuration excluding the control unit in the work device. This is a perspective view showing the approach image of the end effector to the workpiece in the example of the device configuration. This is a partially enlarged view of the rotating unit of the work device. This is a perspective view of the link actuation device of the rotating unit. This is a front view of a simplified model in which the two link mechanisms of the link actuation device are omitted. This is a partial cross-sectional view of the line VI-VI in Figure 5. This is a diagram showing one of the link mechanisms of the link actuation device represented by a straight line. This is a simplified block diagram showing the control unit of the work device. This is a block diagram of the control unit of the work device. This is a diagram showing the coordinate system of the workpiece on which the work device performs work. This is a diagram explaining the reference point of the workpiece, etc. This is a diagram showing vector A on the workpiece and vector B on which the end effector performs work. This is a diagram explaining the method of setting vector A on the workpiece. This is a coordinate point P on the surface of the workpiece. １ and the next coordinate point P ２ From vector A １ This figure shows an example of setting the coordinates P on the surface of the workpiece. ｍ and the next coordinate point P ｍ＋１ From vector A ｍThis figure shows an example of setting the parameters. This figure illustrates how to set the vector B that the end effector performs work on. This figure shows the normal vector to the object at the teaching point. This flowchart shows the process of determining the amount of rotation in the control unit. This is a front view of the work device according to the second embodiment of the present invention. This is a perspective view conceptually showing an example of the device configuration excluding the control unit in the work device. This is a perspective view showing the approach image of the end effector to the workpiece in the example device configuration. This is a perspective view conceptually showing an example of the device configuration excluding the control unit in the work device according to the third embodiment of the present invention. This is a perspective view showing the approach image of the end effector to the workpiece in the example device configuration. This is a perspective view conceptually showing an example of the device configuration excluding the control unit in the work device according to the fourth embodiment of the present invention. This is a perspective view showing the approach image of the end effector to the workpiece in the example device configuration. This is a perspective view conceptually showing an example of the device configuration excluding the control unit in the work device according to the fifth embodiment of the present invention. This is a perspective view showing the approach image of the end effector to the workpiece in the example device configuration. This is a perspective view conceptually showing an example of the device configuration excluding the control unit in the work device according to the sixth embodiment of the present invention. This is a perspective view showing the approach image of the end effector to the workpiece in the example device configuration. This is a conceptual diagram illustrating a case where the amount of rotation of the end effector is inappropriate relative to the defined direction of movement on the surface of the workpiece. This is a conceptual diagram illustrating a case where the amount of rotation of the end effector is appropriate relative to the defined direction of movement on the surface of the workpiece.

[0020] [First Embodiment] A work apparatus according to the first embodiment of the present invention will be described with reference to Figures 1 to 13B and Figure 21B. The work apparatus is used, for example, in medical equipment or industrial equipment. The following description also includes a description of a work method for performing work on an object to be worked on.

[0021] <Overall Structure of the Working Device> As shown in Figures 1, 2A, and 2B, the working device 1 performs work by controlling the position and angle of the end effector Ee on the workpiece 2, which is the object to be worked on. The working device 1 comprises a linear motion mechanism 63, a rotary unit Ru, and a control unit Cu as shown in Figure 1. The linear motion mechanism 63 is installed on a frame 62 fixed to the floor or the like, and the rotary unit Ru is attached to the guide (third sliding part) 67b of the third linear actuator 67, which is the output part of the linear motion mechanism 63. Regarding the combination of linear motion axes of the linear motion mechanism 63, in this embodiment the link actuator 7 is moved on the XYZ axes, but as will be described later, the workpiece 2 may also be moved, or for example, the link actuator 7 may be arranged on the Z axis and the workpiece 2 on the XY axes.

[0022] The rotating unit Ru comprises a link actuator 7 and a rotating mechanism Ra. The end effector Ee is rotatably supported around its working axis Ca (Figure 3) via the rotating mechanism Ra on the tip member 40 of the link actuator 7, which will be described later. The base end link hub 12 (Figure 3), which will be described later, of the link actuator 7 is attached to the output section of the linear motion mechanism 63.

[0023] The workpiece 2, which is the object to be worked on, is placed on a workpiece platform 8 by a conveying device 5 such as a conveyor and transported. Instead of placing the workpiece 2 on the workpiece platform 8, the workpiece 2 may be lifted from the conveying device 5 by a workpiece lifting device 8A when it is time for the work process. Alternatively, instead of transporting the workpiece 2 with the conveying device 5, a worker or another robot may place the workpiece 2 on the workpiece platform 8.

[0024] The work device 1 performs work by positioning the end effector Ee, which is supported by the tip member 40 of the link actuation device 7, relative to the workpiece 2. The rotary unit Ru and the linear motion mechanism 63 are electrically connected to the same control unit Cu, for example, and are synchronously controlled by this control unit Cu.

[0025] <About the Link Actuator> As shown in Figures 4 and 5, the link actuator 7 comprises a parallel link mechanism 9 and an attitude control actuator 10 that actsuates the parallel link mechanism 9. <Parallel Link Mechanism> The parallel link mechanism 9 connects the link hub 13 at the tip end to the link hub 12 at the base end via three sets of link mechanisms 14, allowing for attitude changes. The number of sets of link mechanisms 14 may be four or more. Note that in Figure 5, only one set of link mechanisms 14 is shown, and the remaining two link mechanisms are omitted.

[0026] Each link mechanism 14 has a base end link member 15, a tip end link member 16, and a central link member 17, forming a four-bar link mechanism consisting of four rotational pairs. The base and tip end link members 15 and 16 are L-shaped, with one end rotatably connected to the base link hub 12 and the tip link hub 13, respectively. The central link member 17 has the other ends of the base and tip end link members 15 and 16 rotatably connected to both ends.

[0027] The parallel link mechanism 9 is a structure that combines two spherical link mechanisms. The central axes of the rotational pairs of the base-side link hub 12 and the base-side end link member 15, and the central axes of the rotational pairs of the base-side end link member 15 and the central link member 17, intersect at the base-side spherical link center PA. Similarly, the central axes of the rotational pairs of the tip-side link hub 13 and the tip-side end link member 16, and the central axes of the rotational pairs of the tip-side end link member 16 and the central link member 17, intersect at the tip-side spherical link center PB.

[0028] Furthermore, the distance between the center of the rotational pair between the base-side link hub 12 and each end-side link member 15 on the base side and the base-side spherical link center PA is the same. The distance between the center of the rotational pair between each end-side link member 15 on the base side and each central link member 17 and the base-side spherical link center PA is the same. Similarly, the distance between the center of the rotational pair between the tip-side link hub 13 and each end-side link member 16 on the tip side and the tip-side spherical link center PB is the same. The distance between the center of the rotational pair between each end-side link member 16 on the tip side and each central link member 17 and the tip-side spherical link center PB is the same. The central axes of the rotational pairs between the base-side and tip-side end-link members 15, 16 and the central link member 17 may have a certain intersection angle γ or may be parallel.

[0029] Figure 6 shows the relationship between the central axis O1 of the rotational pairs of the base-side link hub 12 and the base-side end link member 15, and the spherical link center PA. The shape and positional relationship of the tip-side link hub 13 (Figure 5) and the tip-side end link member 16 (Figure 5) are the same as in Figure 6, although they are not shown. In Figure 6, the angle α formed by the central axis O1 of the rotational pairs of the base-side link hub 12 and the base-side end link member 15, and the central axis O2 of the rotational pairs of the base-side end link member 15 and the central link member 17, is 90°. However, the angle α may be other than 90°.

[0030] The three sets of link mechanisms 14 have the same geometric shape. Geometrically identical shape means that, as shown in Figure 7, the geometric model in which each link member 15, 16, and 17 are represented by straight lines, that is, the model represented by each rotational pair and the straight lines connecting these rotational pairs, has a shape in which the base end portion and the tip end portion are symmetrical with respect to the central part of the central link member 17, regardless of the orientation. Figure 7 is a diagram in which one set of link mechanisms 14 is represented by straight lines. The parallel link mechanism 9 of this embodiment is of the rotationally symmetric type, and the positional relationship between the base end link hub 12 and the base end link member 15 and the tip end link hub 13 and the tip end link member 16 is configured to be rotationally symmetric with respect to the center line C of the central link member 17. The central part of each central link member 17 is located on a common orbital circle D.

[0031] The base link hub 12, the tip link hub 13, and three sets of link mechanisms 14 constitute a two-degree-of-freedom mechanism in which the tip link hub 13 can rotate freely around two orthogonal axes relative to the base link hub 12. In other words, the tip link hub 13 is configured as a mechanism that allows for two degrees of freedom of rotation and change of orientation relative to the base link hub 12. This two-degree-of-freedom mechanism is compact while allowing for a wide range of motion of the tip link hub 13 relative to the base link hub 12.

[0032] For example, if the central axes QA and QB of the base and tip link hubs 12 and 13 are defined as straight lines passing through the base and tip spherical link centers PA and PB and intersecting perpendicularly with the central axes O1 (Figure 6) of the respective rotational pairs of the base and tip link hubs 12 and 13 and the base and tip end link members 15 and 16, then the maximum bending angle θ is the maximum value of the bending angle θ between the central axis QA of the base link hub 12 and the central axis QB of the tip link hub 13. ｍａｘ The angle can be set to approximately ±90°. Furthermore, the rotation angle φ of the tip-side link hub 13 relative to the base-side link hub 12 can be set within the range of 0° to 360°. The bending angle θ is the vertical angle at which the central axis QB of the tip-side link hub 13 is inclined relative to the central axis QA of the base-side link hub 12. On the other hand, the rotation angle φ is the horizontal angle at which the central axis QB of the tip-side link hub 13 is inclined relative to the central axis QA of the base-side link hub 12. The maximum bending angle θ is also shown. ｍａｘ It is acceptable for the angle to be 90 degrees or greater.

[0033] The orientation of the tip-side link hub 13 relative to the base-side link hub 12 is changed using the intersection point O of the central axis QA of the base-side link hub 12 and the central axis QB of the tip-side link hub 13 as the center of rotation. Even if the orientation of the tip-side link hub 13 relative to the base-side link hub 12 changes, the distance L between the spherical link centers PA and PB of the base-side and tip-side links does not change.

[0034] As shown in FIGS. 6 and 7, when all of the following conditions are satisfied in this parallel link mechanism 9, due to geometric symmetry, the proximal link hub 12 and the proximal end link member 15 move in the same manner as the distal link hub 13 and the distal end link member 16. Therefore, when transmitting rotation from the proximal end side to the distal end side, the parallel link mechanism 9 functions as a constant velocity universal joint in which the proximal end side and the distal end side have the same rotation angle and rotate at a constant velocity.

[0035] Condition 1: The angle of the central axis O1 of the revolute pair between the proximal and distal link hubs 12, 13 and the proximal and distal end link members 15, 16 in each link mechanism 14, and the lengths from the proximal and distal spherical link centers PA, PB are equal to each other. Condition 2: The central axis O1 of the revolute pair between the proximal and distal link hubs 12, 13 and the proximal and distal end link members 15, 16 of each link mechanism 14, and the central axis O2 of the revolute pair between the proximal and distal end link members 15, 16 and the central link member 17 intersect the proximal and distal spherical link centers PA, PB on the proximal side and the distal side, respectively. Condition 3: The geometric shapes of the proximal end link member 15 and the distal end link member 16 are equal. Condition 4: The geometric shapes of the proximal portion and the distal portion of the central link member 17 are equal. Condition 5: With respect to the symmetry plane of the central link member 17, the angular positional relationship between the central link member 17 and the proximal and distal end link members 15, 16 is the same on the proximal side and the distal side.

[0036] As shown in FIGS. 4 and 5, the proximal link hub 12 includes a flat plate-shaped proximal end member 6 and three rotating shaft connecting members 21 provided integrally with the proximal end member 6. As shown in FIG. 6, the proximal end member 6 has a circular through hole 6a in the central portion, and the three rotating shaft connecting members 21 are arranged around the through hole 6a at equal intervals in the circumferential direction. As shown in FIGS. 5 and 6, the center of the through hole 6a is located on the central axis QA of the proximal link hub 12. A rotating shaft 22 whose axis intersects the central axis QA of the proximal link hub 12 is rotatably connected to each rotating shaft connecting member 21. One end of the proximal end link member 15 is connected to the rotating shaft 22.

[0037] As shown in Fig. 6, the rotating shaft 22 has a large-diameter portion 22a, a small-diameter portion 22b, and a male screw portion 22c sequentially along the axial direction, and is rotatably supported by the rotating shaft connecting member 21 via two bearings 23 at the small-diameter portion 22b. The bearing 23 is, for example, a ball bearing such as a deep groove ball bearing or an angular contact ball bearing. These bearings 23 are installed and fixed with the outer circumferential surface of the outer ring fitted in an inner diameter groove provided in the rotating shaft connecting member 21. The types and installation methods of bearings provided in other rotating kinematic pairs are also the same.

[0038] The rotating shaft 22 is arranged concentrically on the output shaft 52a of the speed reduction mechanism 52 described later at the large-diameter portion 22a. One end of the proximal end link member 15 is connected to the rotating shaft 22 so as to rotate integrally with the rotating shaft 22. A notch 25 is formed at one end of the proximal end link member 15, and both side portions of this notch 25 constitute a pair of inner and outer rotating shaft support portions 26 and 27. Through holes are formed in the pair of rotating shaft support portions 26 and 27, respectively. The rotating shaft connecting member 21 is disposed in the notch 25, and the small-diameter portion 22b of the rotating shaft 22 is inserted through the through holes and the inner circumferential surface of the inner ring of the bearing 23. The male screw portion 22c of the rotating shaft 22 protrudes inward beyond the inner rotating shaft support portion 27.

[0039] A spacer 28 is fitted on the outer circumference of the large-diameter portion 22a of the rotating shaft 22, and the proximal end link member 15 and the output shaft 52a of the speed reduction mechanism 52 are fixed by a bolt 29 via this spacer 28. Further, a nut is screwed onto the male screw portion 22c of the rotating shaft 22. A spacer is interposed between the end surface of the inner ring of the bearing 23 and the pair of rotating shaft support portions 26 and 27, and a preload is applied to the bearing 23 when the nut is screwed.

[0040] A rotating shaft 35 is connected to the other end of the base-side end link member 15, and is rotatably connected to one end of the central link member 17. Similar to the rotating shaft 22 of the base-side link hub 12, this rotating shaft 35 has a large diameter portion 35a, a small diameter portion 35b, and a male thread portion 35c, and is rotatably supported at one end of the central link member 17 via two bearings 36 at the small diameter portion 35b. A notch 37 is formed at the other end of the base-side end link member 15, and the portions on both sides of this notch 37 constitute a pair of inner and outer rotating shaft support portions 38 and 39. Through holes are formed in these rotating shaft support portions 38 and 39, respectively. The male thread portion 35c protrudes inward from the inner rotating shaft support portion 39.

[0041] One end of the central link member 17 is positioned within the notch 37, and the small diameter portion 35b is inserted through the through hole and the inner circumferential surface of the inner ring of the bearing 36. Furthermore, a nut is screwed onto the male threaded portion 35c. A spacer is interposed between the inner ring end face of the bearing 36 and the pair of rotating shaft support portions 38 and 39, and preload is applied to the bearing 36 when the nut is screwed on.

[0042] As shown in Figure 4, the tip-side link hub 13 has a flat tip member 40 and three rotating shaft connecting members 41 provided on the bottom surface of the tip member 40 at equal circumferential intervals. The center of the circumference on which each rotating shaft connecting member 41 is located is on the central axis QB (Figure 5) of the tip-side link hub 13. A rotating shaft 43 whose axis intersects the central axis QB (Figure 5) of the tip-side link hub 13 is rotatably connected to each rotating shaft connecting member 41. One end of the tip-side end link member 16 is connected to this rotating shaft 43. The other end of the tip-side end link member 16 is connected to a rotating shaft 45 which is rotatably connected to the other end of the central link member 17.

[0043] <Attitude Control Actuator> As shown in Figures 4 and 6, the attitude control actuator 10 is a rotary actuator provided with a speed reduction mechanism 52, and is installed coaxially with the rotating shaft 22 on the base end member 6 of the base-end link hub 12. The attitude control actuator 10 and the speed reduction mechanism 52 are integrally provided, and the speed reduction mechanism 52 is fixed to the base end member 6 by a motor fixing member 53. Note that the attitude control actuator 10 may be of a type equipped with a brake.

[0044] In this example, the attitude control actuator 10 is provided on all three sets of link mechanisms 14. However, if the attitude control actuator 10 is provided on at least two of the three sets of link mechanisms 14, the attitude of the distal link hub 13 relative to the proximal link hub 12 can be determined. The three attitude control actuators 10 are arranged such that their rotation shafts 22 are orthogonal to the central axis QA (Figure 5) of the proximal link hub 12, and the central position P, which is the intersection of the rotation shafts 22 of these attitude control actuators 10, １０ is located on the central axis QA (Figure 5) of the proximal link hub 12.

[0045] As shown in Figure 6, the speed reduction mechanism 52 is of flange output type and has a large-diameter output shaft 52a. The distal end surface of the output shaft 52a is formed as a planar flange surface 54 orthogonal to the center line of the output shaft 52a. The output shaft 52a is connected via the spacer 28 to the rotation shaft support portion 26 of the proximal end link member 15 with a bolt 29. The large-diameter portion 22a of the rotation shaft 22, which constitutes a rotational pairing portion between the proximal link hub 12 (Figure 5) and the proximal end link member 15, is fitted into an inner diameter groove 57 provided in the output shaft 52a of the speed reduction mechanism 52.

[0046] As shown in Figures 5 and 6, the link actuator 7 drives each attitude control actuator 10 to rotate, thereby actuating the parallel link mechanism 9. Specifically, when the attitude control actuator 10 is rotationally driven, its rotation is decelerated via the speed reduction mechanism 52 and transmitted to the rotation shaft 22. Thereby, the angle of the proximal end link member 15 relative to the proximal link hub 12 is changed, and the attitude of the distal link hub 13 relative to the proximal link hub 12 is arbitrarily changed.

[0047] <About the End Effector> As shown in Figures 5 and 21B, the end effector Ee is rotatably supported around the work axis Ca on the tip member 40 of the tip-side link hub 13 via a rotating mechanism Ra. The end effector Ee performs work on the workpiece 2 with or without contact. Examples of the end effector Ee include a hand including a gripper, a cleaning nozzle, a dispenser, a welding torch, a knife, a laser oscillator, and image processing equipment. However, the end effector Ee is not limited to these.

[0048] <Rotation Mechanism> The rotation mechanism Ra is attached to the tip member 40 of the tip-side link hub 13. As shown in Figure 3, the rotation mechanism Ra includes a rotation actuator 18 for rotation control and a reduction gear (not shown) for reducing the rotation of the rotation actuator 18. In this example, a motor with a reduction gear, in which the rotation actuator 18 and the reduction gear are integrally provided, is used as the rotation mechanism Ra. The output section of the rotation mechanism Ra rotates around the work axis Ca.

[0049] <Linear Motion Mechanism> As shown in Figure 1, the linear motion mechanism 63 has first, second, and third linear actuators 65, 66, and 67 whose directions of movement are mutually orthogonal. Specifically, as shown in Figures 2A and 2B, the linear motion mechanism 63 is fitted with an XYZ stage that moves in three orthogonal axis directions. The first linear actuator 65 moves back and forth in the X-axis direction (left-right direction in Figure 1). The second linear actuator 66 moves back and forth in the Y-axis direction, which is the front-back direction perpendicular to the X-axis direction. The third linear actuator 67 moves back and forth in the Z-axis direction, which is perpendicular to the X-axis direction and the Y-axis direction, respectively. In this example, the Z-axis direction is set to be the up-down direction.

[0050] As shown in Figure 1, the first, second, and third linear actuators 65, 66, and 67 are driven by motors 65a, 66a, and 67a, respectively, and each has a conversion mechanism (not shown) such as a ball screw that converts the rotation of each motor 65a, 66a, and 67a into linear reciprocating motion. The first linear actuator 65 has a guide 65b, which is the first sliding part, a slide table 65c, which is the first sliding part, and a motor 65a. The guide 65b, which is the first sliding part, extends along the X-axis. The second linear actuator 66 has a guide 66b, which is the second sliding part, a slide table 66c, which is the second sliding part, and a motor 66a. The guide 66b, which is the second sliding part, extends along the Y-axis. The first and second linear actuators 65 and 66 are arranged such that the forward and backward directions of the first and second sliding parts, the slide tables 65c and 66c, are perpendicular to each other.

[0051] The third linear actuator 67 includes a slide table 67c, which is a third sliding part, a guide 67b, which is a third sliding part, and a motor 67a. The guide 67b, which is a third sliding part, extends along the Z-axis direction. The third linear actuator 67 is positioned such that the direction of movement of the guide 67b, which is a third sliding part, is perpendicular to the direction of movement of the slide tables 65c and 66c, which are the first and second sliding parts, respectively.

[0052] A guide 65b of the first linear actuator 65 is attached to the frame 62, and a guide 66b of the second linear actuator 66 is connected to a slide table 65c, which is driven to move back and forth along the guide 65b that extends along the X-axis direction, via a connecting and fixing member 68. A slide table 67c is connected to a slide table 66c, which is driven to move back and forth along the guide 66b that extends along the Y-axis direction, via a connecting and fixing member 69. Alternatively, the slide table 67c of the third linear actuator 67 may be directly fixed to the slide table 66c of the second linear actuator 66. The guide 67b of the third linear actuator 67, which is driven to move back and forth relative to the slide table 67c, becomes the output section of the linear mechanism 63.

[0053] A rotating unit Ru is attached to the guide 67b, which serves as the output section. In other words, a link actuation device 7 is attached to the lower end of the guide 67b. In this configuration, the rotating unit Ru can be installed at the lower end of the guide 67b of the third linear actuator 67, and since the guide 67b of the third linear actuator 67 and the rotating unit Ru move in conjunction, the number of parts around the rotating unit Ru is reduced, and the working area can be widened.

[0054] In this embodiment, the rotary unit Ru is installed at the lower end of the guide 67b of the third linear actuator 67, but the rotary unit Ru may also be installed at a location other than the lower end of the guide 67b of the third linear actuator 67. The first or second linear actuators 65 and 66 may be used as the output section of the linear mechanism 63.

[0055] <Control Unit> As shown in Figure 1, the control unit Cu determines the position and angle of the linear motion mechanism 63, the link actuator 7, and the rotary mechanism Ra, and gives movement commands to each actuator. As shown in Figure 8, the control unit Cu comprises a teaching control unit 70 and an actuator positioning control unit 71. The teaching control unit 70 includes a storage unit 72 for storing teaching data 72a, a setting unit 73 having vector A and B setting means described later, and a calculation unit 74. Teaching data 72a created in work coordinates is created by teaching or direct teaching by a controller (not shown). The teaching data 72a is stored in the storage unit 72 in a rewritable manner.

[0056] <Work Coordinate System Image> The control unit Cu determines the reference point (Wx=0, Wy=0, Wz=0) of the workpiece 2, which is the object to be worked on, as shown in Figures 10A and 10B. This reference point (0,0,0) is an arbitrary position on the workpiece 2, and in the example of Figure 10A, it is the center point of the bottom surface of the roughly rectangular parallelepiped workpiece 2. The control unit Cu (Figure 8) teaches the working position (Wx, Wy, Wz) of the workpiece 2 considered from the reference point, the angle made with the Wx-Wy plane, the angle made with Wx when viewed from the Wz direction, and the amount of rotation of the end effector Ee around the working axis Ca (Figure 3) to determine the working direction (θ',φ',θz'). The working position (Wx,Wy,Wz) and the working direction (θ',φ',θz') are stored in the storage unit 72 as teaching data 72a, as shown in Figure 8.

[0057] As shown in Figure 9, the setting unit 73 has a vector A setting means 73a for setting vector A and a vector B setting means 73b for setting vector B. As shown in Figure 11, vector A is the orientation and magnitude on the work path RT of the surface of the workpiece 2, which is the work object, from the teaching data. In other words, vector A is the direction in which it moves on the work surface. Vector B includes the orientation, magnitude, and rotation amount θz' of the end effector performing the work, from the teaching data. In other words, vector B is the direction in which the end effector does the work. The calculation unit 74 shown in Figure 8 defines the rotation amount θz' of the end effector so that vectors A and B shown in Figure 11 are closest neighbors (the dot product is maximized). Note that a matching solution is obtained when vector A and the vector n below are strictly perpendicular. In reality, there are accuracy issues with vectors A and n, and it is rare for vectors A and B to perfectly match.

[0058] <Regarding Vector A> As shown in Figures 9 and 12A to 12C, the vector A setting means 73a sets, for example, the coordinate point Pm (Wxm, Wym, Wzm) on the work surface and the next coordinate point P ｍ＋１ (W ｘｍ＋１ ,W ｙｍ＋１ ,W ｚｍ＋１ ) Let vector A be set from point P. ｍ Vector A in ｍ It is defined as follows:

[0059] Although the above calculation method is very simple, if the distance between coordinate points is large, it may not be possible to obtain an accurate direction.

[0060] <Regarding Vector B> As shown in Figures 13A to 13C, the approach direction of the end effector to workpiece 2 can be easily taught. Specifically, the normal vector n between the teaching point and the object is defined as the approach direction. The normal vector n is uniquely determined and, in the case of a link actuation device, is defined by θ' and φ'. On the other hand, determining the rotation amount θz' of the end effector is complex. Therefore, for the time being, θz' is treated as an unknown, and vector B is defined from the three angle parameters mentioned above. Point P ｍ Vector B in ｍ It is defined as follows: (f, g, and h are functions that can contain θ'm, φ'm, and θz'm in their formulas, respectively)

[0061]

[0062] As shown in Figure 9, the calculation unit 74 includes a dot product calculation means 74a, a rotation amount determination means 74b, and a teaching data reflection means 74c. The dot product calculation means 74a calculates the dot product of vectors A and B. The rotation amount determination means 74b determines the rotation amount of vector B that maximizes the dot product calculated by the dot product calculation means 74a. The teaching data reflection means 74c reflects the rotation amount of vector B determined by the rotation amount determination means 74b into the teaching data 72a.

[0063] <Flow of rotation amount θz'> As shown in Figure 14, the work method for controlling the position and angle of the end effector relative to the workpiece comprises a vector A setting process S1, a vector B setting process S2, a dot product value calculation process S3, a rotation amount determination process S4, and a teaching data reflection process S5. The vector A setting process S1 sets vector A from the teaching data, which is the orientation and magnitude of the surface on the work path of the workpiece. The vector B setting process S2 sets vector B from the teaching data, which includes the orientation, magnitude, and rotation amount of the end effector performing the work.

[0064] The dot product calculation process S3 calculates the dot product of vectors A and B. The teaching data reflection process S5 reflects the amount of rotation of vector B, determined in the rotation amount determination process S4, into the teaching data. These vector A setting process S1, vector B setting process S2, dot product calculation process S3, rotation amount determination process S4, and teaching data reflection process S5 are executed sequentially by the vector A setting means 73a, vector B setting means 73b, dot product calculation means 74a, rotation amount determination means 74b, and teaching data reflection means 74c shown in Figure 9.

[0065] The working position (Wx, Wy, Wz) and working direction (θ', φ', θz') of the workpiece, as indicated by the teaching data 72a of the workpiece coordinates that reflect the amount of rotation θz', are converted into machine coordinates in the actuator positioning control unit 71, and movement commands are given to each actuator.

[0066] <Effects> According to the work apparatus 1 and work method shown in Figures 1 and 9 described above, the amount of rotation of the end effector Ee is automatically calculated so that the dot product value of vectors A and B calculated by the dot product value calculation means 74a is maximized. Therefore, compared to conventional techniques that rely on the operator's experience to adjust the twist angle of the end effector, the operator's man-hours can be reduced. Consequently, it becomes possible to control the position and angle of the end effector Ee with high precision and fine-grained movement relative to the workpiece 2. Even when the workpiece 2 is a three-dimensional curved surface or when it moves to trace the object along a complex path, it becomes possible to control the position and angle of the end effector Ee with high precision and fine-grained movement relative to the workpiece 2 while reducing the operator's man-hours. Specifically, as shown in Figure 2A, the rotational degrees of freedom Rf1 of the rotating mechanism Ra and the rotational degrees of freedom Rf2 and Rf3 of the link actuation device 7 are adjusted to align the direction of travel 2D on the workpiece 2 with the working direction ED of the end effector Ee shown in Figures 2A and 2B. In this way, the position and angle of the end effector Ee relative to the workpiece 2 can be controlled with high precision and fine-grained movement.

[0067] Because the work device 1 is equipped with a link actuator 7, it can control the position and angle of the end effector Ee smoothly and quickly without singularities, compared to a typical vertical articulated robot. The link actuator 7 in Figure 4 can move the link hub 13 on the tip side linearly to the desired posture, thus shortening the cycle time compared to configurations such as those of a typical vertical articulated robot. In addition, cables and other wiring can be passed through the internal space of the link actuator 7, and the wiring will not twist even when the rotational movement is repeated, making wiring management easier.

[0068] <Regarding Other Embodiments> In the following description, parts corresponding to matters previously described in each embodiment will be denoted by the same reference numerals, and redundant explanations will be omitted. When only a part of the configuration is described, the other parts of the configuration will be the same as those in the previously described embodiment unless otherwise specified. The same configuration will produce the same effects. Not only are combinations of the parts specifically described in each embodiment possible, but it is also possible to partially combine embodiments, provided that there are no particular problems with the combination.

[0069] [Second Embodiment: Rotation Mechanism on the Workpiece Side, Figures 15-16B] As shown in Figure 15, the rotation actuator 18 of the rotation mechanism Ra may rotate the workpiece, which is the object being worked on. As shown in Figures 16A and 16B, a link actuator 7 is supported at the output of the linear motion mechanism 63, and an end effector Ee is directly supported on the tip member 40 of this link actuator 7. The rotation mechanism Ra is supported on the workpiece mounting table 8 or the workpiece lifting device 8A (Figure 15), and the workpiece 2 is rotatable around an axis determined by the rotation mechanism Ra. In Figures 16A and 16B, the hatched area is the rotation mechanism Ra. The embodiments in Figures 15-16B also provide the same effects as the first embodiment.

[0070] In the following embodiments of the work apparatus, the control unit is omitted, but a control unit Cu similar to that in Figure 1 or Figure 15 is provided and electrically connected to each actuator. The following embodiments also provide the same effects as the first embodiment.

[0071] [Third Embodiment: End Effector Handling, Rotating Mechanism at the Base of the Link Actuator, Figures 17A-17B] In the work apparatus 1 shown in Figures 17A and 17B, the base end member 6 of the link actuator 7 is supported by the output section of the linear motion mechanism 63 via a rotating mechanism Ra, indicated by hatching. The end effector Ee is supported on the tip member 40 of this link actuator 7. The workpiece 2, which is the object to be worked on, is placed on, for example, a workpiece mounting table 8.

[0072] [Fourth Embodiment: Work Handling, Rotating Mechanism at the Base of the End Effector, Figures 18A-18B] In the work apparatus 1 shown in Figures 18A and 18B, the base member 6 of the link actuator 7 is supported at the output of a linear motion mechanism 63A to which an XY stage that moves in two orthogonal axes is applied. The workpiece 2, which is the object to be worked on, is attached to the tip member 40 of the link actuator 7. In addition, the end effector Ee is supported at the output of another linear motion mechanism 63B equipped with a Z stage, via a rotating mechanism Ra shown in hatching. Regarding the combination of linear motion axes, in this embodiment the link actuator 7 is moved on the XY axes and the end effector Ee is moved on the Z axis, but it is not limited to this configuration and can be freely arranged. In work handling in which the workpiece 2 is attached to the tip member 40 of the link actuator 7, the apparatus is more compact than in the other embodiments described above, which is advantageous in terms of the degree of freedom in arranging the apparatus.

[0073] [Fifth Embodiment: Work Handling, Rotating Mechanism at the Base of the Link Actuator, Figures 19A-19B] In the work apparatus 1 shown in Figures 19A and 19B, the base end member 6 of the link actuator 7 is supported via a rotating mechanism Ra, shown in hatching, at the output of the linear motion mechanism 63A to which the XY stage is applied. The workpiece 2, which is the object to be worked on, is attached to the tip member 40 of the link actuator 7. In addition, an end effector Ee is supported at the output of another linear motion mechanism 63B equipped with a Z stage.

[0074] [Sixth Embodiment: Work Handling, Rotating Mechanism at the Base of the Workpiece, Figures 20A-20B] In the work apparatus 1 shown in Figures 20A and 20B, the base end member 6 of the link actuator 7 is supported at the output section of the linear motion mechanism 63A to which the XY stage is applied. The workpiece 2, which is the object to be worked on, is attached to the tip member 40 of the link actuator 7 via the rotating mechanism Ra shown in hatching. In addition, an end effector Ee is supported at the output section of another linear motion mechanism 63B equipped with a Z stage.

[0075] <Vertical Articulated Robot> It is also possible to apply a vertical articulated robot in place of the linear motion mechanism 63 and rotary unit Ru in Figure 1.

[0076] As described above, preferred embodiments have been explained with reference to the drawings, but various additions, modifications, and deletions are possible without departing from the spirit of the present invention. Therefore, such additions and deletions are also included within the scope of the present invention.

[0077] 1…Working device 2…Workpiece 7…Link actuation device 10…Actuator for attitude control 12…Link hub at the base end 13…Link hub at the tip end 14…Link mechanism 15, 16…End link members at the base end and tip end 17…Central link member 18…Rotation actuator 40…Tip member 63…Linear motion mechanism 65, 66, 67…First, second and third linear motion actuators 72a…Teaching data 73a…Vector A setting means 73b…Vector B setting means 74a…Dot product calculation means 74b…Rotation amount determination means 74c…Teaching data reflection means Ee…End effector Ra…Rotation mechanism

Claims

1. A work device that controls the position and angle of an end effector on a workpiece to perform work, comprising: a vector A setting means for setting a vector A which is the orientation and magnitude of the surface on the work path of the workpiece from teaching data; a vector B setting means for setting a vector B which includes the orientation, magnitude and amount of rotation of the end effector to perform work from the teaching data; a dot product calculation means for calculating the dot product value of vectors A and B; a rotation amount determination means for determining the amount of rotation of vector B that maximizes the dot product value calculated by the dot product calculation means; and a teaching data reflection means for reflecting the amount of rotation of vector B determined by the rotation amount determination means to the teaching data.

2. A work device according to claim 1, comprising: a linear motion mechanism having linear actuators whose directions of movement are mutually orthogonal; and a rotary mechanism having a rotary actuator for rotating the end effector or the workpiece.

3. A work device according to claim 1 or 2, wherein the tip member is equipped with a link actuation device that supports the end effector or the workpiece.

4. The work device according to claim 3, wherein the link actuation device is such that the tip-side link hub is connected to the base-side link hub via three or more link mechanisms so as to be able to change its orientation, and each link mechanism has a base-side and tip-side end link member, one end of which is rotatably connected to the base-side link hub and the tip-side link hub, and a central link member, both ends of which are rotatably connected to the other ends of these base-side and tip-side end link member, and two or more of the three or more link mechanisms are equipped with an attitude control actuator for arbitrarily controlling the orientation of the tip-side link hub.

5. A work method for performing work on a workpiece by controlling the position and angle of an end effector, comprising: a vector A setting process for setting a vector A which is the orientation and magnitude of the surface on the work path of the workpiece from teaching data; a vector B setting process for setting a vector B which includes the orientation, magnitude and amount of rotation of the end effector performing the work from the teaching data; an inner product calculation process for calculating the inner product value of vectors A and B; a rotation amount determination process for determining the amount of rotation of vector B that maximizes the inner product value calculated in the inner product calculation process; and a teaching data reflection process for reflecting the amount of rotation of vector B determined in the rotation amount determination process to the teaching data.

Images