Work equipment

Abstract

To provide a work machine that can reduce vibrations of a tip end part of an actuating mechanism, with good responsiveness, during high-speed operation or with respect to complicate and finely-tuned operation.SOLUTION: A work device 1 comprises a link operation device 7, a movement mechanism 62 and a control device Cu. In the link operation device 7, a link hub 13 at a tip end side is connected to a link hub 12 at a base end side through a link mechanism 14 so that a posture thereof can be changed. In the movement mechanism 62, the link hub 12 at the base end side is mounted on a second linearly moving actuator 66 acting as an output part. The control device Cu controls an actuator 10 for controlling a posture of the link operation device 7 and first, second and third linearly moving actuators 65, 66 and 67. The control device Cu controls other actuators so that inertia force generated in either of the movement mechanism 62 and the link operation device 7 is cancelled.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a working device used in equipment that requires high speed, high precision, a wide operating range, and fine-grained movement, such as medical equipment or industrial equipment. [Background technology]

[0002] In the prior art, a robot arm has been proposed that includes a vibration detection unit that detects vibrations and a vibration correction unit that applies a force in the opposite phase to the vibrations detected by the vibration detection unit (Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-169619 Summary of the Invention [Problem to be solved by the invention]

[0004] In a robot arm such as that described in Patent Document 1, the joints are rotatably arranged in series, resulting in a complex structure. Therefore, a vibration detection unit such as a vibration sensor is required to detect vibrations at the tip. Furthermore, because the joints are rotatably arranged in series, driving only some of the joints is not sufficient to apply vibrations of opposite phases in various directions; the entire robot arm must be driven. In this case, the large inertia of the entire robot arm results in low responsiveness, making it difficult to suppress vibrations during high-speed or complex, detailed movements.

[0005] An object of the present invention is to provide a working device that can reduce vibrations at the tip of the operating mechanism with good responsiveness during high-speed operation or complex, fine-grained operation. [Means for solving the problem]

[0006] The working device of the present invention comprises an actuation mechanism 7 and a movement mechanism 62, The actuation mechanism 7 is provided with a distal end member 40 connected to a base end member 6 via a link mechanism 14 so as to be able to change its posture, and a posture control actuator 10 for arbitrarily changing the posture of the distal end member 40 relative to the base end member 6, The movement mechanism 62 is a working device having actuators 65, 66, 67 and Ra for driving movement, which serve as output parts, and the base end member 6 is attached to the actuators for driving movement, A control device Cu is provided to control the attitude control actuator 10 and the movement drive actuators 65, 66, 67, and Ra, and this control device Cu controls the actuator of either the movement mechanism 62 or the operating mechanism 7 so as to cancel out the inertial force generated in the other.

[0007] According to this configuration, it is possible to reduce vibrations occurring at the tip of the tip member 40 by controlling the actuator of either the moving mechanism 62 or the operating mechanism 7 so as to cancel out the inertial force caused by acceleration or deceleration of the other of the moving mechanism 62 or the operating mechanism 7. Therefore, it is possible to reduce vibrations at the tip of the operating mechanism 7 with good responsiveness during high-speed operations or complex, fine movements.

[0008] The control device Cu may control the other actuator so as to generate inertia in the opposite direction to at least a component of the movable direction component of the inertial force generated in either the moving mechanism 62 or the operating mechanism 7. The component force is a force in a direction caused by vibration. In this case, since inertia in the opposite direction to at least a component of one of the inertial forces in the moving direction is generated, vibration of the operating mechanism 7 can be effectively and quickly reduced with a slight movement.

[0009] The system may include three or more sets of link mechanisms 14, each of which has base-side and tip-side end link members 15, 16 rotatably connected at one end to the base-side link hub 12 and tip-side link hub 13, respectively, and a central link member 17 rotatably connected at both ends to the other ends of the base-side and tip-side end link members 15, 16, and the attitude control actuator 10 may be provided in two or more sets of link mechanisms 14 out of the three or more sets of link mechanisms 14. According to this configuration, the base-end link hub 12, the tip-end link hub 13, and three or more sets of link mechanisms 14 form a two-degree-of-freedom mechanism in which the tip-end link hub 13 can rotate freely around two perpendicular axes relative to the base-end link hub 12. In other words, the tip-end link hub 13 can rotate with two degrees of freedom relative to the base-end link hub 12, allowing for free posture change. This two-degree-of-freedom mechanism is compact, yet allows for a wide range of movement of the tip-end link hub 13 relative to the base-end link hub 12.

[0010] The control device Cu may have an inertial force calculation unit 68 that calculates the inertial force and its direction, an operation amount calculation unit 69 that calculates an operation amount that generates inertia in the opposite direction from the inertial force and its direction calculated by the inertial force calculation unit 68, and a control unit 70 that performs control to adjust the timing of executing an operation based on the operation amount calculated by the operation amount calculation unit 69. In this way, the control device Cu can generate inertia in the opposite direction on either the moving mechanism 62 or the operating mechanism 7 in response to movement of the other side by calculating the operation amount that generates inertia in the opposite direction and adjusting the timing of executing the operation.

[0011] The inertial force calculation unit 68 may calculate the inertial force when the movement drive actuators 65, 66, 67, and Ra are accelerating or decelerating from the movement direction and speed of the movement drive actuators 65, 66, 67, and Ra. In this case, the direction in which the inertial force acts and the magnitude of the inertial force can be easily calculated from the command values ​​for the movement direction and speed of the movement drive actuators 65, 66, 67, and Ra, eliminating the need for a vibration detection unit such as a vibration sensor and simplifying the structure.

[0012] The operation amount calculation unit 69 may calculate the operation amount by decomposing the inertial force calculated by the inertial force calculation unit 68 and its direction into a tangential plane direction of the operating range of the operating mechanism 7. Because vibration is caused by a force in the tangential plane direction of the operating range of the operating mechanism 7 due to the structure of the operating mechanism 7, the inertial force of the actuators 65, 66, 67 and Ra for driving the movement of the movement mechanism 62 during acceleration or deceleration can be decomposed into a tangential plane direction of the operating range of the operating mechanism 7, and inertia in the opposite direction can be added to the component force, thereby effectively reducing the vibration of the operating mechanism 7 with a slight movement.

[0013] The movement mechanism 62 may be equipped with a linear motion unit 63 including first, second, and third linear motion actuators 65, 66, and 67 that move forward and backward in three orthogonal axis directions. In this case, by combining the linear motion unit 63 with the operating mechanism 7, the operating mechanism 7 can be moved at high speed in various directions. This makes it possible to provide a working device that can be applied to various workpieces and can shorten takt time, and also increases the versatility of the working device.

[0014] The movement mechanism 62 may have a rotary actuator Ra serving as an output unit. In this case, by rotating the operating mechanism 7 with the rotary actuator Ra, the working range for the workpiece can be increased, enabling finer movements. This makes it possible to shorten the time required for changeovers.

[0015] This working device may be an appearance inspection device 1A, 1B in which an image processing device Eg is mounted on the operating mechanism 7. In this case, the appearance inspection process, which has previously been performed by humans visually inspecting from various directions, can be automated with high speed and high accuracy. In addition, by reducing the vibration of the image processing device Eg, it becomes possible to obtain blur-free images. [Effects of the Invention]

[0016] According to the working device of the present invention, the actuator of either the moving mechanism or the operating mechanism is controlled so as to cancel out the inertial force generated in the other, thereby enabling vibrations at the tip of the operating mechanism to be reduced responsively during high-speed operations or complex, fine-grained operations. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a block diagram of a control system of a working device according to a first embodiment of the present invention. [Figure 2A] FIG. 2 is a perspective view of a link actuator of the working device. [Figure 2B] FIG. 10 is a perspective view showing another posture of the link actuator. [Figure 2C] FIG. 5 is a partial cross-sectional view taken along the line IIC-IIC in FIG. [Figure 3] FIG. [Figure 4] FIG. 10 is a front view of a simplified model of the link actuator in which two link mechanisms are omitted. [Figure 5] FIG. 2 is a diagram showing one link mechanism of the link actuator device in a straight line. [Figure 6] 10A and 10B are diagrams showing an example of a configuration in which the link actuator is combined with a linear motion unit. [Figure 7A] FIG. 2 is a perspective view showing the operating range of the link actuator. [Figure 7B] FIG. 4 is a front view showing the operating range of the link actuator. [Figure 8A] FIG. 10 is a perspective view showing an example in which inertia in the opposite direction is generated by the link actuator. [Figure 8B] 10 is a diagram conceptually showing an example in which inertia in the opposite direction is generated by the link actuator. FIG. [Figure 9A] FIG. 10 is a perspective view of a visual inspection device in which an image processing device is mounted on the link actuator. [Figure 9B] FIG. 10 is a perspective view of a visual inspection device in which another image processing device is mounted on a link actuator. [Figure 10A] 9B is a front view showing an example of the configuration of the appearance inspection device of FIG. 9A. [Figure 10B] FIG. 9C is a front view showing an example of the configuration of the appearance inspection device of FIG. 9B. [Figure 11] FIG. 10 is a front view of a working device according to a second embodiment of the present invention. [Figure 12] FIG. 10 is a front view of a working device according to a third embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0018] [First embodiment] A working device according to an embodiment of the present invention will be described with reference to FIGS. 1 to 10B. 1, the working apparatus 1 includes a link actuator 7, which is an actuation mechanism, a movement mechanism 62, and a control device Cu. This working apparatus 1 is used in, for example, medical equipment or industrial equipment. <Outline of the working device structure> This working device 1 is configured by combining a link actuator 7 and a linear motion unit 63, which is a movement mechanism 62. The linear motion unit 63, which moves back and forth in three orthogonal axial directions, is mounted on a stand or the like (not shown), and the link actuator 7 is attached to an actuator for movement drive, which serves as the output section of the linear motion unit 63. The working device 1 performs work by positioning an end effector attached to a tip member 40 of the link actuator 7 with respect to a workpiece (not shown). The link actuator 7 and linear motion unit 63 are connected to a control device Cu, and are synchronously controlled by this control device Cu.

[0019] <About the link actuator> As shown in FIG. 2A, the link actuation device 7 includes a parallel link mechanism 9 and an actuator 10 for posture control that operates the parallel link mechanism 9. <Parallel link mechanism> The parallel link mechanism 9 has a link hub 13 on the tip side connected to a link hub 12 on the base side so as to be able to change its posture via three sets of link mechanisms 14. The number of sets of link mechanisms 14 may be four or more. In Figure 4, only one set of link mechanisms 14 is shown, with the remaining two link mechanisms being omitted.

[0020] Each link mechanism 14 has an end link member 15 on the base end side, an end link member 16 on the tip end side, and a central link member 17, and forms a four-bar chain link mechanism consisting of four revolute pairs. As shown in Fig. 2B, the base-side and tip-side end link members 15, 16 are substantially L-shaped, with one end rotatably connected to the base-side link hub 12 and the tip-side link hub 13, respectively. As shown in Fig. 4, the other ends of the base-side and tip-side end link members 15, 16 are rotatably connected to both ends of the central link member 17, respectively.

[0021] The parallel link mechanism 9 has a structure in which two spherical link mechanisms are combined. The central axes of the revolute pairs between the base-end link hub 12 and the base-end end link member 15, and the revolute pairs between the base-end end link member 15 and the central link member 17, intersect at the base-end spherical link center PA. Similarly, the central axes of the revolute pairs between the tip-end link hub 13 and the tip-end end link member 16, and the revolute pairs between the tip-end end link member 16 and the central link member 17, intersect at the tip-end spherical link center PB.

[0022] The distance between the center of the rotation pair between the base end link hub 12 and the base end end link member 15 and the base end spherical link center PA is the same. The distance between the center of the rotation pair between the base end end link member 15 and the central link member 17 and the base end spherical link center PA is the same. Similarly, the distance between the center of the rotation pair between the tip end link hub 13 and the tip end link member 16 and the tip end spherical link center PB is the same. The distance between the center of the rotation pair between the tip end link member 16 and the central link member 17 and the tip end spherical link center PB is the same.

[0023] The central axes of the rotation pairs between the base end side and tip end side end link members 15, 16 and the central link member 17 may have a certain cross angle γ or may be parallel to each other. The arm angle, which is the angle formed by the central axis of each rotation pair between the base-end link hub 12 and the base-end end link member 15 and the central axis of each rotation pair between the base-end end link member 15 and the central link member 17, is specified to a predetermined angle.

[0024] The three link mechanisms 14 have geometrically identical shapes. "Geometrically identical shapes" refers to a geometric model in which each link member 15, 16, and 17 is represented by straight lines, i.e., a model represented by each rotation pair and the lines connecting these rotation pairs, in which the base end and tip end portions are symmetrical with respect to the center of the central link member 17, regardless of the posture of the model, as shown in FIG. 5. FIG. 5 is a diagram showing one link mechanism 14 represented by straight lines. The parallel link mechanism 9 of this embodiment is rotationally symmetric, and the positional relationship between the base end link hub 12 and the base end end link member 15 and the tip end link hub 13 and the tip end end link member 16 is rotationally symmetric with respect to the center line C of the central link member 17. The centers of each central link member 17 are located on a common orbital circle.

[0025] The base-end link hub 12, the tip-end link hub 13, and the three link mechanisms 14 form a two-degree-of-freedom mechanism in which the tip-end link hub 13 can rotate freely around two perpendicular axes relative to the base-end link hub 12. In other words, the tip-end link hub 13 can rotate with two degrees of freedom relative to the base-end link hub 12, allowing for free posture change. This two-degree-of-freedom mechanism is compact, yet allows for a wide range of movement of the tip-end link hub 13 relative to the base-end link hub 12.

[0026] For example, if the straight lines passing through the base-end and tip-end spherical link centers PA and PB and intersecting at right angles with the central axes O1 (FIG. 2A) of the base-end and tip-end link hubs 12 and 13 and the base-end and tip-end end link members 15 and 16 are defined as the central axes QA and QB of the base-end and tip-end link hubs 12 and 13, respectively, the maximum bending angle θ between the central axis QA of the base-end link hub 12 and the central axis QB of the tip-end link hub 13 is maxcan be set to approximately 90°. Also, as shown in FIG. 3, the pivot angle φ of the tip-side link hub 13 relative to the base-side link hub 12 can be set in the range of 0° to 360°. As shown in FIG. 5, 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 pivot 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. Note that the maximum bending angle θ max may be 90° or more.

[0027] The position of the distal link hub 13 relative to the proximal link hub 12 is changed around the intersection O of the central axis QA of the proximal link hub 12 and the central axis QB of the distal link hub 13. The solid line in FIG. 7B indicates a state in which the central axis QA of the proximal link hub 12 (FIG. 4) and the central axis QB of the distal link hub 13 (FIG. 4) are collinear, and the two-dot chain line in FIG. 7B indicates a state in which the central axis QB of the distal link hub 13 (FIG. 4) forms a certain operating angle (bend angle) with respect to the central axis QA of the proximal link hub 12 (FIG. 4). As shown in FIG. 5, even if the position of the distal link hub 13 relative to the proximal link hub 12 changes, the distance L between the proximal and distal spherical link centers PA and PB does not change.

[0028] In this parallel link mechanism 9, when all of the following conditions are met, due to geometric symmetry, the base-end link hub 12 and base-end end link member 15 and the tip-end link hub 13 and tip-end end link member 16 will move in the same way. Therefore, when transmitting rotation from the base end to the tip end, the parallel link mechanism 9 functions as a constant velocity universal joint, where the base end and tip end sides rotate at a constant speed with the same rotation angle.

[0029] Condition 1: As shown in Figures 2C and 5, the angles α of the central axes O1 and O2 of the rotation pairs of the base-end and tip-end link hubs 12 and 13 and the base-end and tip-end end link members 15 and 16 in each link mechanism 14, as well as the lengths from the base-end and tip-end spherical link centers PA and PB, are equal to each other. Condition 2: The central axes of the rotation pairs between the base-end and tip-end link hubs 12, 13 of each link mechanism 14 and the base-end and tip-end end link members 15, 16, and the central axes of the rotation pairs between the base-end and tip-end end link members 15, 16 and the central link member 17 intersect with the base-end and tip-end spherical link centers PA, PB at the base-end and tip-end sides. Condition 3: The geometric shapes of the end link member 15 on the base end side and the end link member 16 on the tip end side are the same. Condition 4: The geometric shapes of the base end portion and the tip end portion of the central link member 17 are the same. Condition 5: The angular positional relationship between the central link member 17 and the end link members 15, 16 on the base end side and the tip end side with respect to the symmetry plane of the central link member 17 is the same on the base end side and the tip end side.

[0030] As shown in FIG. 2A, the base-side link hub 12 has a flat base-side member 6 and three rotary shaft connecting members 21 that are integral with the base-side member 6. The base-side member 6 has a circular through-hole 6a in its central portion, and three rotary shaft connecting members 21 are arranged around the through-hole 6a at equal intervals in the circumferential direction. The center of the through-hole 6a is located on the central axis QA of the base-side link hub 12, as shown in FIG. 4. Each rotary shaft connecting member 21 is rotatably connected to a rotary shaft 22, as shown in FIG. 3, whose axis intersects with the central axis QA of the base-side link hub 12. One end of the base-side end link member 15 is connected to the rotary shaft 22.

[0031] The tip-side link hub 13 has a flat tip member 40 and three rotary shaft connecting members 41 provided at equal intervals in the circumferential direction on the bottom surface of this tip member 40. The center of the circumference on which each rotary shaft connecting member 41 is arranged is located on the central axis QB of the tip-side link hub 13. A rotary shaft 43 whose axis intersects with the central axis QB of the tip-side link hub 13 is rotatably connected to each rotary shaft connecting member 41. One end of the tip-side end link member 16 is connected to this rotary shaft 43. The other end of the tip-side end link member 16 is connected to a rotary shaft 45 that is rotatably connected to the other end of the central link member 17.

[0032] <Attitude control actuator> 2A is a rotary actuator equipped with a speed reducing mechanism 52, and is installed coaxially with the rotation shaft 22 on one plane of the base end member 6 of the link hub 12 on the base end side. The attitude control actuator 10 and the speed reducing mechanism 52 are provided integrally, and the speed reducing mechanism 52 is fixed to the base end member 6 by a motor fixing member 53. The attitude control actuator 10 may be equipped with a brake.

[0033] In this example, all three link mechanisms 14 are provided with attitude control actuators 10, but if attitude control actuators 10 are provided in at least two of the three link mechanisms 14, the attitude of the tip-side link hub 13 relative to the base-side link hub 12 can be determined. The three attitude control actuators 10 are arranged so that their rotation axes 22 are perpendicular to the central axis QA (Figure 4) of the base-end link hub 12, and the central position, which is the intersection of the rotation axes 22 of these attitude control actuators 10, is on the central axis QA (Figure 4) of the base-end link hub 12.

[0034] 3, the link actuation device 7 rotates and drives each attitude control actuator 10, thereby actuating the parallel link mechanism 9. More specifically, when the attitude control actuator 10 is rotated, the rotation is reduced via the speed reduction mechanism 52 and transmitted to the rotation shaft 22. This changes the angle of the base-end end link member 15 relative to the base-end link hub 12, and the attitude of the tip-end link hub 13 relative to the base-end link hub 12 can be changed as desired.

[0035] <End effector> An end effector, which is the tip portion, is attached to the tip member 40 of the tip-side link hub 13. Examples of the end effector include a hand including a gripper, a cleaning nozzle, a dispenser, a welding torch, and an image processing device Eg (FIGS. 9A and 9B).

[0036] The image processing device Eg shown in FIG. 9A has, for example, a camera Cm that captures an image of a workpiece. The working device in this case is a visual inspection device 1A in which the image processing device Eg is mounted on a link actuation device 7, as shown in FIG. 10A. The image processing device Eg shown in FIG. 9B includes, for example, a camera Cm that captures an image of the workpiece and a lighting fixture Le that illuminates the workpiece. The working device in this case is a visual inspection device 1B in which the image processing device Eg is mounted on a link actuation device 7, as shown in FIG. 10B. In each of the working devices in FIGS. 10A and 10B, at least the camera Cm is electrically connected to a camera control system (not shown) via wiring, and various controls during shooting are performed by the camera control system.

[0037] <Linear motion mechanism> As shown in FIG. 6, an XYZ stage that moves forward and backward in three orthogonal axial directions is applied to a linear motion unit 63, which is a movement mechanism. The linear motion unit 63 has first, second, and third linear motion actuators 65, 66, and 67, which are actuators for driving movement. The first linear motion actuator 65 moves forward and backward in the X-axis direction, which is the left-right direction in FIG. 6. The second linear motion actuator 66, which serves as an output unit, moves forward and backward in the Y-axis direction, which is the front-rear direction perpendicular to the X-axis direction. The third linear motion actuator 67 moves forward and backward in the Z-axis direction, which is perpendicular to both the X-axis direction and the Y-axis direction. In this example, the Z-axis direction is set to be the up-down direction.

[0038] The first, second, and third linear actuators 65, 66, and 67 are driven by motors 65a, 66a, and 67a, respectively, and each includes a conversion mechanism (not shown), such as a ball screw, that converts the rotation of the motors 65a, 66a, and 67a into linear reciprocating motion. Each linear actuator 65, 66, and 67 includes a guide 65b, 66b, or 67b extending along the corresponding axis, a slide table that slides along the guide 65b, 66b, or 67b, and a motor 65a, 66a, or 67a. In this example, the link hub 12 at the base end of the link actuator 7 is attached to the slide table of the second linear actuator 66, which serves as the output unit. By arranging the linear actuator unit 63, which moves back and forth in three orthogonal axes, and attaching the link actuator 7 to its final stage, the end effector attached to the distal end member 40 can achieve a high degree of freedom of movement.

[0039] <About the control system> 1 controls the actuator 10 for controlling the attitude of the link actuation device 7 so as to cancel out the inertial force caused by acceleration or deceleration of the linear motion unit 63. Specifically, the control device Cu controls the bending angle θ and the swivel angle φ (FIG. 3) of the link actuation device 7 when accelerating or decelerating the linear motion unit 63, for example, when positioning the linear motion unit 63. The acceleration or deceleration during positioning or the like refers, in this example, to the acceleration region in which the linear motion unit 63 moves from a stopped state to a uniform motion, or conversely, the deceleration region in which the linear motion unit 63 moves from a uniform motion to a stopped state. Hereinafter, this acceleration or deceleration during positioning or the like may be referred to as "settling time."

[0040] During settling, the control device Cu controls the bending angle θ and the rotation angle φ (Figure 3) of the link actuator 7 to generate inertia at the tip of the end effector in the opposite direction to that of the linear motion unit 63, thereby reducing vibrations occurring in the end effector.

[0041] <Regarding the trajectory of the tip of the link actuator 7> Here, when an end effector is attached to the tip member 40 of the link actuator 7 and mass point A at the tip of this end effector is considered, Figures 7A and 7B show the trajectory that mass point A traces as a result of the operation of the link actuator 7. As shown in Figure 7A, the trajectory Ls that mass point A traces as a result of the link actuator 7 is approximately hemispherical, and the link actuator 7 performs high-speed, high-precision, and smooth positioning operation within this approximately hemispherical operating range S.

[0042] As shown in Figure 6, in a configuration in which the link actuator 7 is attached to the final stage of the linear motion unit 63, when the link actuator 7 is moved by the linear motion unit 63 in the direction of arrow A1, inertia occurs due to the movement, and a force due to that inertia acts when the movement is complete. Figure 6 also shows the inertial force F acting on the mass point A at the tip of the end effector.

[0043] <Load acting on the tip of the end effector due to stage deceleration and inertia in the opposite direction> Focus on the link actuator 7 in the working device 1 of Fig. 6. In Fig. 8A, when the link actuator 7 is in a certain position (bend angle θ, swivel angle φ), an inertial force F is applied to the mass point A due to the movement of at least one of the XYZ stages in the linear motion unit 63 (Fig. 6).

[0044] Figure 8B shows a conceptual diagram with the link mechanism and other components omitted. Figure 8B shows the attitudes of mass point A and the link actuator (bend angle θ, swing angle φ), as well as the inertial force F acting on mass point A. The shaded area indicates the operating range Sa of mass point A when the link actuator is moved by a small angle from its current attitude (bend angle θ, swing angle φ). This operating range Sa of the shaded area is a partially spherical area obtained by partially cutting out a portion of the operating range S (Figure 7A). The rectangle Sb shown by the two-dot chain line in Figure 8B indicates the tangent plane at mass point A to the approximately hemispherical surface of the operating range S.

[0045] The inertial force F caused by the movement of the linear motion unit 63 (Fig. 6) can be broken down into a tangential force Ft and a force Fn in the direction perpendicular to that plane. Due to its structure, the link actuator has high rigidity against the force Fn in the direction perpendicular to the plane, but low rigidity against the tangential force Ft, and the Ft component, which is the component of the inertial force F in the moving direction, is one of the causes of vibration. 8B, this embodiment is characterized by controlling the link actuator to apply inertia Fr in the opposite direction to the tangential plane component Ft of the inertial force F, i.e., by moving (dθ, dφ), the Ft component is reduced. Although it does not affect the Fn component in the perpendicular direction, the link actuator has high rigidity in the perpendicular direction to begin with, and does not affect vibration.

[0046] To reduce inertial force, the link actuator moves by dθ and dφ, changing from the specified posture [(θ, φ) → (θ + dθ, φ + dφ)], but it can be moved to a point taking the amount of movement into consideration in advance, and controlled so that the moved point becomes the specified point [(θ - dθ, φ - dφ) → (θ, φ)]. In this case, it becomes possible to position the link actuator with higher precision.

[0047] The above functions are controlled by the control device Cu in Fig. 1. Specifically, the control device Cu has an inertial force calculation unit 68, an operation amount calculation unit 69, and a control unit 70. The inertial force calculation unit 68 calculates the inertial force and its direction caused by the linear motion unit 63. For example, the inertial force calculation unit 68 can easily and quickly calculate the direction and magnitude of the inertial force acting when the first, second, and third linear motion actuators 65, 66, and 67 of the linear motion unit 63 are accelerating or decelerating, based on command values ​​for the movement directions and speeds of these linear motion actuators 65, 66, and 67.

[0048] The movement amount calculation unit 69 calculates a movement amount (dθ, dφ) that generates inertia in the opposite direction from the current attitude (θ, φ) of the link actuation device 7 and the calculated inertial force and its direction. This movement amount calculation unit 69 calculates the movement amount by breaking down the inertial force and its direction calculated by the inertial force calculation unit 68 into tangential plane directions of the movement range of the link actuation device 7. The control unit 70 adjusts the timing for executing the movement according to the calculated movement amount. This timing is usually set to the time when the linear motion actuators 65, 66, 67 are accelerating or decelerating, but may also be determined by, for example, determining an appropriate timing through testing and / or simulation.

[0049] <Action and effect> According to the working apparatus 1 described above, the bending angle and pivot angle (θ, φ) of the link actuator 7 are controlled to cancel out the inertial force caused by the acceleration or deceleration of the linear motion unit 63, thereby generating inertia at the tip of the end effector in the opposite direction to that of the linear motion unit 63. This reduces vibrations generated in the end effector attached to the tip member 40 of the link actuator 7. This eliminates the need for a vibration detection unit such as a vibration sensor, and enables responsive reduction of vibrations in the end effector during high-speed or complex, fine-grained movements. With this working apparatus 1, work can be performed stably even when the acceleration is set high, thereby shortening the takt time with an inexpensive configuration, even during high-speed or complex, fine-grained movements.

[0050] The operating range of the tip of the link actuator 7 is approximately hemispherical, and the inertial force and its direction that can be controlled by the bending angle and rotation angle (θ, φ) are limited to the tangential direction of the approximately hemispherical surface, but due to the structure of the link actuator 7, it is the force in the tangential direction that causes vibration. For this reason, the inertial force (resultant force of the X, Y, and Z axes) when the linear motion unit 63 accelerates or decelerates is resolved in the tangential direction of the operating range of the link actuator 7, and inertia in the opposite direction is added to the force in the tangential direction. This makes it possible to effectively reduce vibration in the link actuator 7 with slight movements.

[0051] Because the linear motion unit 63 including the first, second, and third linear motion actuators 65, 66, 67 is combined with the link actuation device 7, the direction in which the inertial force acts and the magnitude of the inertial force can be easily calculated from the command values ​​for the movement direction and speed of each linear motion actuator 65, 66, 67. This eliminates the need to provide a vibration detection unit such as a vibration sensor, and the structure of the working device 1 can be simplified.

[0052] Also, for example, an acceleration sensor or a speed sensor can be attached to the tip of the link actuation device 7, and the control device Cu calculates the direction of the inertial force generated by the movement of the linear motion unit 63 from the detected sensor output. Furthermore, the control device Cu has a calculation function that calculates the movement amount (dθ, dφ) of the link actuation device 7, which is inertia in the opposite direction to the tangential plane direction of the inertial force of the linear motion unit 63, from the current attitude (θ, φ) of the link actuation device 7. This makes it possible to efficiently generate inertia in the opposite direction on the link actuation device side with respect to the movement of the linear motion unit 63.

[0053] However, if an image processing unit such as a camera or lighting fixture is mounted on the end effector, vibrations during shooting may result in blurred images. It is possible to obtain blur-free images by shortening the exposure time, but this requires a large amount of light, which limits the options for lighting fixtures that can be mounted.

[0054] In this embodiment, when the end effector is a camera Cm as shown in FIG. 9A or an image processing device Eg including a camera Cm and a lighting device Le as shown in FIG. 9B, a device configuration that can reduce vibrations makes it possible to acquire blur-free images. Therefore, the increased number of options for the image processing device that can be installed increases design flexibility. Depending on the usage conditions, it is possible to select an image processing device Eg without a lighting device as shown in FIG. 9A, which can reduce costs compared to an image processing device with a lighting device. Furthermore, the appearance inspection device 1A (FIG. 10A) or 1B (FIG. 10B) equipped with the image processing device Eg can automate the appearance inspection process, which previously required manual visual inspection from various directions, with high speed and high accuracy.

[0055] <Other embodiments> In the following description, parts corresponding to matters previously described in each embodiment are given the same reference numerals, and duplicated description will be omitted. When only a part of the configuration is described, the other parts of the configuration are the same as the previously described embodiment unless otherwise specified. The same configuration produces the same effects. It is possible to combine not only the parts specifically described in each embodiment, but also partially combine embodiments as long as there is no particular problem with the combination.

[0056] [Second embodiment: FIG. 11 (rotary actuator)] The movement mechanism 62 is not limited to the linear motion unit described above, and a rotary actuator Ra shown in Fig. 11 may also be applied. In this working apparatus 1C, a rotary actuator (movement drive actuator) Ra, which serves as the output section of the movement mechanism 62, is installed on a stand or the like (not shown), and a link hub 12 on the base end side of the link actuation device 7 is attached to this rotary actuator Ra. In the working apparatus 1C of this example, the central axis QA (see Fig. 4) of the link hub 12 on the base end side of the link actuation device 7 and the rotation axis Ca of the rotary actuator Ra are arranged coaxially.

[0057] In this case, if the direction of the inertial force of the rotary actuator Ra can be detected, it is possible to reduce the inertial force in the tangential direction by the link actuator 7. Also, by rotating the link actuator 7 with the rotary actuator Ra, a larger working range for the workpiece can be secured, allowing for finer movement. This makes it possible to shorten the time required for changeovers, etc. Other effects similar to those described above are also achieved.

[0058] [Third embodiment: FIG. 12 (linear motion unit + rotary actuator)] As shown in Fig. 12, the movement mechanism 62 may be a combination of a linear motion unit 63 and a rotary actuator Ra. In this working device 1D, the linear motion unit 63 is mounted on a stand or the like (not shown), and the link hub 12 on the base end side of the link actuation device 7 is attached via the rotary actuator Ra to a second linear motion actuator 66, which serves as the output section of the linear motion unit 63. In this case, the end effector attached to the tip member 40 of the link actuation device 7 can achieve movement with an even higher degree of freedom due to the linear motion of the linear motion unit 63 and the rotational motion of the rotary actuator Ra. Other effects similar to those described above are also achieved.

[0059] The linear motion unit 63 in the first and third embodiments is applied with an XYZ stage that moves back and forth in the three axial directions of X, Y and Z, respectively, but may also be configured with two linear motion actuators that move back and forth in any two axial directions of X, Y and Z. A vertical articulated robot or a horizontal articulated robot may be used as the movement mechanism, and a link actuator may be attached to the tip of the robot, which serves as the output section.

[0060] While the inertial force generated by the movement mechanism is canceled by the link actuation device as described above, the reverse is also possible, and the inertial force generated by the link actuation device may be canceled by the movement mechanism. Specifically, the control device Cu in FIG. 1 controls the first, second, and third linear actuators 65, 66, and 67, which are actuators for the movement mechanism, so as to cancel the inertial force generated in the link actuation device 7. In this case, the inertial force calculation unit 68 of the control device Cu calculates the inertial force generated when accelerating or decelerating the tip of the end effector of the attitude control actuator 10 based on the movement direction and speed of the attitude control actuator 10. However, depending on the type of movement mechanism, there may be no restriction on inertia in the opposite direction, making it possible to generate an operation that completely cancels the inertial force of the link actuation device.

[0061] Although a parallel link structure is shown as the link actuation device, any structure capable of controlling the bending angle θ and the rotation angle φ may be used, and a pan-tilt structure (not shown) may also be used as the actuation mechanism.

[0062] Although the embodiments of the present invention have been described above, the disclosed embodiments are illustrative in all respects and are not limiting. The scope of the present invention is defined by the claims, not by the above description, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0063] 1, 1C, 1D...Working device, 1A, 1B...Appearance inspection device (working device), 6...Base end member, 7...Link actuation device (actuation mechanism), 10...Actuator for attitude control, 12...Base end link hub, 13...Tip end link hub, 14...Link mechanism, 15...Base end end link member, 16...Tip end end link member, 17...Central link member, 40...Tip end member, 62...Moving mechanism, 63...Linear motion unit, 65, 66, 67...First, second and third linear motion actuators (actuators for moving and driving), 68...Inertia force calculation unit, 69...Operation amount calculation unit, 70...Control unit, Cu...Control device, Eg...Image processing device, Ra...Rotational actuator

Claims

1. An actuation mechanism and a movement mechanism are provided, The actuation mechanism connects the distal end member to the proximal end member via a link mechanism so as to be able to change its position. and an actuator for controlling the attitude of the distal end member relative to the proximal end member. A computer is provided, The movement mechanism has an actuator for driving the movement, which serves as an output section. A working device in which the base end member is attached to an actuator, a control unit for controlling the attitude control actuator and the movement drive actuator; A control device is provided, and the control device is connected to either the moving mechanism or the operating mechanism. The other actuator is controlled to cancel out the generated inertial force. The control device has an inertial force calculation unit that calculates the inertial force and its direction, a movement amount calculation unit that calculates a movement amount that generates inertia in the opposite direction from the inertial force and its direction calculated by the inertial force calculation unit, and a control unit that controls adjustment of a timing for executing a movement according to the movement amount calculated by the movement amount calculation unit, The operation amount calculation unit calculates the operation amount by decomposing the inertial force calculated by the inertial force calculation unit and its direction into a tangential plane direction of a motion range of the actuation mechanism.

2. 2. The working apparatus according to claim 1, wherein the control device controls the actuator of the other of the moving mechanism and the operating mechanism so as to generate inertia in an opposite direction to at least a component of a movable direction component of inertial force generated in either the moving mechanism or the operating mechanism.

3. 3. A working device according to claim 1 or 2, comprising three or more sets of the link mechanisms, each of the link mechanisms having base-end and tip-end end link members rotatably connected at one end to a base-end link hub and a tip-end link hub, respectively, and a central link member rotatably connected at both ends to the other ends of the base-end and tip-end end link members, and wherein the attitude control actuator is provided in two or more sets of link mechanisms out of the three or more sets of link mechanisms.

4. 4. The working device according to claim 1, wherein the inertial force calculation unit calculates the inertial force when the movement drive actuator is accelerating or decelerating from the movement direction and speed of the movement drive actuator.

5. 5. The working device according to claim 1, wherein the movement mechanism comprises a linear motion unit including first, second and third linear motion actuators that move forward and backward in three orthogonal axial directions.

6. 6. The working device according to claim 1, wherein the movement mechanism has a rotary actuator serving as an output section.

7. 7. The working device according to claim 1, wherein the working device is an appearance inspection device in which an image processing device is mounted on the operating mechanism.

Images