Linkage action device

Abstract

The control device (70) of the link action device (7) has a posture calculating unit (74), an actuator position calculating unit (75), and a teaching data storage unit (76). When teaching the front end side link hub (13) by direct teaching, the posture calculating unit (74) calculates the posture of the front end side link hub (13) by forward transformation from the position of the actuator (10) in a state where no pre-pressure is applied to the parallel link mechanism (9). The actuator position calculating unit (75) calculates the position of the actuator (10) in a state where pre-pressure is applied to the parallel link mechanism (9) by inverse transformation based on the posture of the front end side link hub (13). The teaching data storage unit (76) stores the posture of the front end side link hub (13) and the position of the actuator (10) calculated by inverse transformation as a set of teaching data.

Description

[0001] Related applications

[0002] This application claims priority to Japanese Patent Application No. 2024-047916, filed on March 25, 2024, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This invention relates to a linkage mechanism requiring precision and a wide range of motion in applications such as medical devices and industrial equipment, and to a technique for improving positioning accuracy through direct teaching. Background Technology

[0004] like Figure 1 As shown, a linkage action device 7 is proposed as a form of parallel mechanism.

[0005] Patent document 1 proposes the following technology: In order to improve the positioning accuracy of a mechanical body with a linkage mechanism, the position after applying a force (pre-pressure) to the gaps generated in each rotating joint or mechanism part of the mechanical body in an attempt to push in one direction is set as the origin position.

[0006] The specific application method of Patent Document 1 will be explained. For example... Figure 2 As shown, consider the case where the attitude of the front-side connecting rod hub 13 is at the origin position (θ0, φ0), and the rotation angle of the end connecting rod component 15 on the base side corresponding to the attitude of the front-side connecting rod hub 13 is (β10, β20, β30).

[0007] At this time, as shown in Table 1, the actuator rotation position (M10, M20, M30) corresponding to the rotation angle of the end connecting rod component 15 on the base side without preload is set as the origin position of the actuator rotation position by superimposing the offset (Preload1, Preload2, Preload3) corresponding to the preload.

[0008] [Table 1]

[0009] Table 1. Rotation angle of the base-end connecting rod corresponding to the attitude of the front-end connecting rod hub of the linkage actuator, and the rotation position of the actuator with and without preload.

[0010]

[0011] Subsequently, positioning actions are performed using this origin position as a reference, and the offset corresponding to the preload is always taken into account. As a result, the gap of the mechanical body can be pushed to one side, thereby improving the positioning accuracy of the mechanical body.

[0012] Existing technical documents

[0013] Patent documents

[0014] Patent Document 1: Japanese Patent No. 5951224 Summary of the Invention

[0015] The problem the invention aims to solve

[0016] However, when manually moving the mechanical body during direct teaching, it is necessary to turn off the actuator's positioning control (and release the brake), or use torque control with the torque output value set lower than the value used for positioning control, thereby releasing the electrical and mechanical constraints. In this case, the preload will disappear. If the actuator rotation position (M1) obtained in the state of preload disappearance is... n M2 n M3 n If the data is set directly as the teaching data, the positioning accuracy of the mechanical body will be worse than that with preload.

[0017] The purpose of this invention is to provide a linkage action device that can improve positioning accuracy even during direct teaching.

[0018] Solution for solving the problem

[0019] Hereinafter, for ease of understanding, the present invention will be described with reference to the accompanying drawings in the embodiments.

[0020] The linkage actuation device of the present invention comprises: a parallel mechanism 9, wherein the front-end linkage hub 13 of the parallel mechanism 9 is connected to the base-end linkage hub 12 via a linkage mechanism 14 in a manner capable of changing its attitude; an actuator 10, which causes the attitude of the front-end linkage hub 13 to change; and a control device 70, which controls the actuator 10, wherein...

[0021] The control device 70 has:

[0022] When the attitude calculation unit 74 teaches the front-side connecting rod hub 13 through direct teaching, the attitude calculation unit 74 calculates the attitude of the front-side connecting rod hub 13 by positive transformation based on the position of the actuator 10 without applying preload to the parallel mechanism 9.

[0023] Actuator position calculation unit 75, based on the calculated attitude of the front-side connecting rod hub 13, calculates the position of the actuator 10 in the state where preload is applied to the parallel mechanism 9 through inverse transformation; and

[0024] The teaching data storage unit 76 stores the attitude of the front-side connecting rod hub 13 and the position of the actuator 10 calculated by inverse transformation as a set of teaching data.

[0025] The term "direct teaching" means manually moving the front-side connecting rod hub 13 to the teaching position.

[0026] According to this structure, when teaching the front-side connecting rod hub 13 through direct teaching, the attitude (θn, φn) of the front-side connecting rod hub 13 is calculated by forward transformation (forward kinematics) based on the position (M1n, M2n, M3n) of the actuator 10 corresponding to the rotation angle (β1n, β2n, β3n) of the end connecting rod component 15 on the base side in the unpreloaded state at the teaching position n selected by the operator. Then, the actuator position (M1n+Preload1, M2n+Preload2, M3n+Preload3) corresponding to the rotation angle of the end connecting rod component 15 on the base side in the preloaded state is calculated by inverse transformation (inverse kinematics). Furthermore, the attitude (θn, φn) of the front-side connecting rod hub 13 and the actuator position (M1n+Preload1, M2n+Preload2, M3n+Preload3) are stored as teaching data. Therefore, since the position of the actuator 10, which excludes the influence of gaps generated in the rotating joints and mechanism parts, can be stored as teaching data, high-precision positioning control can be achieved even during direct teaching.

[0027] The control device 70 can perform positioning control on the actuator 10 based on the teaching data stored in the teaching data storage unit 76. After the teaching performed by direct teaching ends, the control device switches to positioning control of the actuator 10 based on the stored teaching data, thereby enabling improved positioning control.

[0028] Alternatively, the parallel mechanism 9 can connect the front-end side connecting rod hub 13 to the base-end side connecting rod hub 12 via three or more sets of linkage mechanisms 14 in a manner that allows for changing the orientation of the linkage.

[0029] Each linkage mechanism 14 has: end linkage components 15 and 16 on the base end side and the front end side, one end of which is rotatably connected to the base end side linkage hub 12 and the front end side linkage hub 13; and a central linkage component 17, both ends of which are rotatably connected to the other ends of these end linkage components 15 and 16 on the base end side and the front end side, respectively.

[0030] The actuator 10 is provided in all three or more of the linkage mechanisms 14.

[0031] According to this structure, the base-side connecting hub 12, the front-side connecting hub 13, and three or more sets of linkage mechanisms 14 constitute a two-degree-of-freedom mechanism as follows: the front-side connecting hub 13 can rotate about two orthogonal axes relative to the base-side connecting hub 12. In other words, the front-side connecting hub 13 is configured with two degrees of rotational freedom relative to the base-side connecting hub 12, and its attitude can be freely changed. Although this two-degree-of-freedom mechanism is compact, it allows for a wide range of motion of the front-side connecting hub 13 relative to the base-side connecting hub 12. Since all three or more sets of linkage mechanisms 14 are equipped with the actuator 10, the front-side connecting hub 13 can be positioned and controlled with high precision compared to setting actuators in only two of the three sets of linkage mechanisms 14.

[0032] Alternatively, the actuator 10 can be a motor mounted on the base-side connecting rod hub 12, and the control device 70 can drive the motor to control the attitude corresponding to the bend angle and rotation angle of the front-side connecting rod hub 13. In this case, the control device 70 can control each motor to change the attitude of the front-side connecting rod hub 13 relative to the base-side connecting rod hub 12 from the current attitude to the target connecting rod attitude (θ, φ).

[0033] The motor can also be configured for positioning and torque control. For example, when the front-side connecting rod hub 13 is taught to any position via direct teaching, the control device 70 can perform torque control on the servo motor or stepper motor. After teaching is completed, the control device 70 can perform positioning control on the servo motor or stepper motor.

[0034] Alternatively, the control device 70 can limit the output of the motor when teaching the front-side connecting rod hub 13 through direct teaching.

[0035] Limiting the output of the motor also includes setting the motor's output to zero.

[0036] In this case, it is possible to prevent the front-side link hub 13 from becoming a resistance when it is manually moved by direct teaching.

[0037] Alternatively, the attitude of the front-side connecting rod hub 13, calculated by the attitude calculation unit 74 through a forward transformation, can be the bending angle and rotation angle of the front-side connecting rod hub 13. In this case, a connecting rod actuation device that can operate over a wide range of motion even with a compact structure can be constructed.

[0038] Alternatively, the torque of the motor can be used to apply a force that pushes the gap of the parallel mechanism 9 towards one side, thereby applying preload to the parallel mechanism 9. In this case, no additional components for applying preload are required, and preload can be easily applied using an existing motor.

[0039] Alternatively, the force that pushes the gap of the parallel mechanism 9 toward one side can be a force that compresses the parallel mechanism 9 in a specified direction.

[0040] The specified direction is appropriately determined based on the setting state of the linkage action device 7.

[0041] For example, when the linkage actuation device 7 is configured such that the central axis of the base-end side linkage hub 12 faces the vertical direction, the specified direction is the vertical direction. When the linkage actuation device 7 is configured such that the central axis of the base-end side linkage hub 12 faces the horizontal direction, the specified direction is the horizontal direction.

[0042] By compressing the parallel mechanism 9 in a specified direction, the inertial torque of the parallel mechanism 9 can be reduced and its rigidity increased, thereby improving the positioning accuracy of the parallel mechanism 9.

[0043] Alternatively, the position of the actuator 10 calculated by the inverse transformation, i.e., the inverse transformation value, is the output value of the absolute encoder 55 that detects the rotational position of the motor. It represents the amount of movement from the origin position of the front-side connecting rod hub 13, which has been pre-applied with a force that pushes the parallel mechanism 9 in a unilateral direction. By employing the absolute encoder 55 that detects the rotational position of the motor in absolute angles, even if the power supply to the connecting rod actuation device 7 is cut off and reconnected, there is no need to perform initial settings again, and it can easily return to the origin.

[0044] Alternatively, the teaching data may be stored in at least one of the following locations: the internal storage area 81 of the linkage action device controller 71, an external storage device 78 that is detachably mounted on the controller 71 or communicatively connected to the controller 71, or an external device 73. In this case, the storage area for storing the teaching data can be selected according to the user's system architecture.

[0045] Alternatively, the torque of the motor that applies force to the parallel mechanism 9 in the direction of pushing it to one side can be set by an input device 72 or other external device 73 electrically connected to the controller 71 for the linkage action device. In this case, the torque of the motor that applies force to the parallel mechanism 9 in the direction of pushing it to one side can be easily set according to the user's system structure.

[0046] Any combination of at least two structures disclosed in the claims and / or description and / or drawings is included in this invention. In particular, any combination of two or more claims in the claims is included in this invention. Attached Figure Description

[0047] The invention will be more clearly understood from the following description of preferred embodiments in conjunction with the accompanying drawings. However, the embodiments and drawings are for illustration and description only and should not be used to limit the scope of the invention. The scope of the invention is defined by the claims. In the drawings, the same reference numerals in a plurality of figures denote the same or corresponding parts.

[0048] Figure 1 This is a perspective view of the linkage action device according to the first embodiment of the present invention.

[0049] Figure 2 This is a front view showing one axis of the linkage mechanism that constitutes the linkage action device.

[0050] Figure 3 for Figure 2 A partial sectional view at line III-III.

[0051] Figure 4 This is a diagram of a linkage mechanism that uses straight lines to represent the linkage action device.

[0052] Figure 5 This is a perspective view of the actuator of the linkage mechanism.

[0053] Figure 6 This is a conceptual diagram for teaching the linkage mechanism via direct teaching.

[0054] Figure 7 This diagram illustrates the structure of a positioning control system that uses this linkage mechanism.

[0055] Figure 8 This diagram illustrates the internal structure of the controller for the linkage mechanism.

[0056] Figure 9 This diagram illustrates the transformation process when teaching the linkage mechanism via direct teaching.

[0057] Figure 10 This is a flowchart showing the process in stages when teaching a linkage mechanism via direct teaching.

[0058] Figure 11 [This is a front view of the parallel mechanism of the linkage action device according to the second embodiment of the present invention.]

[0059] Figure 12 for Figure 11 AA view.

[0060] Figure 13 for Figure 11 BB view. Detailed Implementation

[0061] [First Implementation Method]

[0062] Reference Figures 1 to 10 The linkage actuation device according to embodiments of the present invention will be described. This linkage actuation device is used, for example, in medical devices or industrial equipment. Figure 1 As shown, the linkage action device 7 includes a parallel linkage mechanism 9 as a parallel mechanism, an actuator 10, and a control device 70.

[0063] Parallel linkage mechanism

[0064] The parallel linkage mechanism 9 is a structure that connects the front-side linkage hub 13 to the base-side linkage hub 12 via three sets of linkage mechanisms 14 in a manner that allows for attitude changes. The number of linkage mechanisms 14 can also be four or more. Figure 2 Only one linkage mechanism 14 is shown; the other two linkage mechanisms are omitted. A workpiece for working on the workpiece is mounted on the front-side linkage hub 13 (the front-side component 40 described later), or the workpiece is mounted thereon. When the workpiece is mounted on the front-side linkage hub 13, the workpiece is located on another device side. When the workpiece is mounted on the front-side linkage hub 13, the workpiece is located on another device side.

[0065] Each linkage mechanism 14 has an end linkage component 15 on the base side, an end linkage component 16 on the front side, and a central linkage component 17, forming a three-section chain linkage mechanism composed of four revolute joints.

[0066] like Figure 1 As shown, the end link components 15 and 16 on the base side and front side are generally L-shaped, with one end rotatably connected to the base side link hub 12 and the front side link hub 13, respectively. Figure 2 As shown, the other ends of the end connecting rod components 15 and 16 on the base end side and the front end side are rotatably connected to the two ends of the central connecting rod component 17.

[0067] The parallel linkage mechanism 9 is a structure obtained by combining two spherical linkage mechanisms. The central axes of the base-side linkage hub 12 and each revolute joint of the base-side end linkage component 15, and the central axes of each revolute joint of the base-side end linkage component 15 and the central linkage component 17, intersect at the center PA of the spherical linkage on the base side. Similarly, the central axes of the front-side linkage hub 13 and each revolute joint of the front-side end linkage component 16, and the central axes of each revolute joint of the front-side end linkage component 16 and the central linkage component 17, intersect at the center PB of the spherical linkage on the front side.

[0068] The distances from the center of each revolute joint between the base-side connecting hub 12 and each end connecting member 15 on the base-side to the center PA of the spherical connecting rod on the base-side are the same. Similarly, the distances from the center of each revolute joint between each end connecting member 15 and each central connecting member 17 on the base-side to the center PA of the spherical connecting rod on the base-side are the same. Likewise, the distances from the center of each revolute joint between the front-side connecting hub 13 and each end connecting member 16 on the front-side to the center PB of the spherical connecting rod on the front-side are the same. The distances from the center of each revolute joint between each end connecting member 16 and each central connecting member 17 on the front-side to the center PB of the spherical connecting rod on the front-side are also the same.

[0069] The central axes of each rotary joint between the end link components 15 and 16 on the base side and the front side and the central link component 17 can have a certain angle γ, or they can be parallel.

[0070] The angles formed by the central axes of the rotating joints between the base-side connecting rod hub 12 and the base-side end connecting rod member 15, and the central axes of the rotating joints between the base-side end connecting rod member 15 and the central connecting rod member 17, i.e., the arm angles, are defined as predetermined angles.

[0071] The three linkage mechanisms 14 have the same geometric shape. The so-called "same geometric shape" means, for example... Figure 4 The figure shows the geometric model obtained by representing each link component 15, 16, and 17 with straight lines. That is, the model is represented by each revolute joint and the straight lines connecting these revolute joints. Regardless of the orientation, the base end portion and the front end portion are symmetrical shapes relative to the central part of the central link component 17. Figure 4 The diagram shows a set of linkage mechanisms 14 represented by straight lines. The parallel linkage mechanism 9 of this embodiment is rotationally symmetric. The positional relationship between the base-side linkage hub 12 and the base-side end linkage member 15 and the front-side linkage hub 13 and the front-side end linkage member 16 is rotationally symmetric with respect to the centerline C of the central linkage member 17. The central portion of each central linkage member 17 lies on a common orbital circle.

[0072] The base-side connecting hub 12, the front-side connecting hub 13, and three sets of linkages 14 constitute a two-degree-of-freedom mechanism, wherein the front-side connecting hub 13 can rotate about two orthogonal axes relative to the base-side connecting hub 12. In other words, the front-side connecting hub 13 relative to the base-side connecting hub 12 is configured as a mechanism whose attitude can be freely changed in two rotational degrees of freedom. Although this two-degree-of-freedom mechanism is compact, it allows for a wide range of motion of the front-side connecting hub 13 relative to the base-side connecting hub 12.

[0073] For example, at the centers PA and PB of the spherical connecting rods that pass through the base end side and the front end side, and at the central axis O1 of each rotary joint of the connecting rod hubs 12 and 13 on the base end side and the end connecting rod components 15 and 16 on the base end side and the front end side ( Figure 1 When perpendicularly intersecting straight lines are taken as the central axes QA and QB of the base-end side and front-end side connecting rod hubs 12 and 13, the maximum value of the angle θ between the central axis QA of the base-end side connecting rod hub 12 (base-end side central axis) and the central axis QB of the front-end side connecting rod hub 13 is the maximum angle θ. max It can be set to approximately 90°. Furthermore, the rotation angle φ of the front-side connecting rod hub 13 relative to the base-side connecting rod hub 12 can be set within the range of 0° to 360°. The bend angle θ refers to the vertical angle at which the central axis QB of the front-side connecting rod hub 13 is tilted relative to the central axis QA of the base-side connecting rod hub 12. On the other hand, the rotation angle φ refers to the horizontal angle at which the central axis QB of the front-side connecting rod hub 13 is tilted relative to the central axis QA of the base-side connecting rod hub 12. Additionally, the maximum bend angle θ... max It can be above 90°.

[0074] The attitude change of the front-end side connecting rod hub 13 relative to the base-end side connecting rod hub 12 is carried out with the intersection point O of the central axis QA of the base-end side connecting rod hub 12 and the central axis QB of the front-end side connecting rod hub 13 as the rotation center. Figure 4 This indicates the state where the central axis QB of the front-side connecting rod hub 13 takes a certain action angle (bending angle) relative to the central axis QA of the base-side connecting rod hub 12. Even if the attitude of the front-side connecting rod hub 13 relative to the base-side connecting rod hub 12 changes, the distance L between the centers PA and PB of the spherical connecting rods on the base side and the front side remains unchanged.

[0075] In this parallel linkage mechanism 9, when all of the following conditions 1 to 5 are met, based on geometric symmetry, the base-side linkage hub 12 and the base-side end linkage member 15 will move in the same way as the front-side linkage hub 13 and the front-side end linkage member 16. Therefore, when the parallel linkage mechanism 9 transmits rotation from the base-side to the front-side, it functions as a constant velocity universal joint, which enables the base-side and front-side to have the same rotation angle and rotate at the same speed.

[0076] Condition 1: such as Figure 3 and Figure 4 As shown, in each linkage mechanism 14, the angles α of the central axes O1 and O2 of the rotary joints of the base end side and front end side linkage hubs 12 and 13 and the end linkage components 15 and 16 on the base end side and front end side, as well as the lengths from the centers PA and PB of the spherical linkages on the base end side and front end side, are equal to each other.

[0077] Condition 2: The central axis of the rotational joint of the base end side and front end side connecting hubs 12 and 13 of each linkage mechanism 14 with the rotational joint of the end connecting rod components 15 and 16 on the base end side and front end side, and the central axis of the rotational joint of the end connecting rod components 15 and 16 on the base end side and front end side with the center PA and PB of the spherical connecting rod on the base end side and front end side.

[0078] Condition 3: The geometry of the end link component 15 on the base side is the same as that of the end link component 16 on the front side.

[0079] Condition 4: The geometry of the base end portion and the front end portion of the central connecting rod component 17 are equal.

[0080] Condition 5: With respect to the plane of symmetry of the central link component 17, the angular positional relationship between the central link component 17 and the end link components 15 and 16 on the base side and the front side is the same on the base side and the front side.

[0081] like Figure 1 As shown, the base-end side connecting rod hub 12 has a flat base end member 6 and three rotating shaft connecting members 21 integrally formed with the base end member 6. On one surface of the base end member 6, the three rotating shaft connecting members 21 are equally spaced in the circumferential direction. Each rotating shaft connecting member 21 is rotatably connected to... Figure 3 The rotating shaft 22 shown is located at the center of the pivot point QA of the base end side connecting rod hub 12. Figure 4 The two ends of the end connecting rod 15 on the base side are connected to the rotating shaft 22.

[0082] like Figure 1 As shown, the front-end connecting rod hub 13 has a flat front end member 40 and three rotating shaft connecting members 41 evenly spaced along the circumferential direction on the bottom surface of the front end member 40. The center of the circumference of each rotating shaft connecting member 41 is located at the central axis QB of the front-end connecting rod hub 13. Figure 4 On each rotating shaft connecting component 41, a rotating shaft 43 is rotatably connected, the axis of which is parallel to the central axis QB of the front end side connecting rod hub 13. Figure 4 The two ends of the front-end connecting rod 16 are connected to the rotating shaft 43. The other end of the front-end connecting rod 16 is connected to the rotating shaft 45, which is rotatably connected to the other end of the central connecting rod 17. Alternatively, the following structure can be adopted: the central axis or front end of the working body or the workpiece disposed on the front-end connecting rod hub 13 (front-end component 40) is aligned with or intersects with the central axis QB of the front-end connecting rod hub 13.

[0083] <Actuator>

[0084] like Figure 5 As shown, the actuator 10 that changes the attitude of the front-side connecting rod hub 13 is equipped with a mechanism that allows the front-side connecting rod hub 13 ( Figure 1 The rotary motor (motor) with brake is a reducer 52 that changes the posture of the motor. The output shaft 54 ​​protrudes from the motor body via the reducer 52. The motor is a servo motor or stepper motor capable of positioning and torque control. The motor is equipped with an absolute encoder 55 to detect the motor's rotational position (absolute angle). Figure 1 As shown, the motor is aligned with the rotating shaft 22 ( Figure 3 The motor body is coaxially mounted on a plane of the base end member 6 of the base end member hub 12. The motor body and the reducer 52 are integrally mounted, and the reducer 52 is fixed to the base end member 6 by the motor fixing member 53.

[0085] In this example, all three sets of linkages 14 are equipped with actuators 10. As long as at least two of the three sets of linkages 14 are equipped with attitude control actuators 10, the attitude of the front-side linkage hub 13 relative to the base-side linkage hub 12 can be determined.

[0086] Three actuators 10 are configured to rotate along their axes 22 ( Figure 3 ) and the central axis QA of the base end connecting rod hub 12 ( Figure 4 These actuators 10 have orthogonal rotating axes 22 ( Figure 3 The intersection point, i.e., the central position, is located at the central axis QA of the connecting rod hub 12 on the base end side. Figure 4 )superior.

[0087] The linkage actuation device 7 drives each actuator 10 by rotation, thereby actuating the parallel linkage mechanism 9. Specifically, when the actuator 10 is driven by rotation, its rotation is reduced in speed by the reducer 52 and then transmitted to the rotating shaft 22. Figure 3 As a result, the angle of the end link component 15 on the base side relative to the base link hub 12 changes, and the posture of the front link hub 13 relative to the base link hub 12 is arbitrarily changed.

[0088] An end effector (not shown) is mounted on the front end component 40 of the front end side link hub 13. Examples of end effectors include robotic arms with grippers, cleaning nozzles, dispensers, welding torches, and image processing equipment with cameras.

[0089] <Control Device>

[0090] Control device 70 controls actuator 10. Control device 70 drives the motor that functions as actuator 10, enabling positioning control of the attitude corresponding to the bend angle and rotation angle of the front-side connecting rod hub 13. Control device 70 is configured to switch between positioning control and torque control. Control device 70 applies a force to the parallel connecting rod mechanism 9, which is a parallel mechanism, pushing the gap in one direction by the torque of the motor, thereby applying preload to the parallel connecting rod mechanism 9. The force that pushes the gap in the parallel connecting rod mechanism 9 in one direction is a force that compresses the parallel connecting rod mechanism 9 in a predetermined direction. Figure 7 As shown, the torque of the motor that applies force in the direction of pushing the parallel linkage 9 to one side can be set by the input device 72 or other external device, i.e., a personal computer (PC) 73, which is electrically connected to the controller 71 for the linkage action device. By rotating each motor provided in each actuator 10 with the same torque in the same direction (clockwise or counterclockwise), a force is applied in the direction of pushing the parallel linkage 9 to one side, thereby pushing the gap to one side, i.e., pushing the gaps of each rotating joint and mechanism part, etc., to one side.

[0091] like Figure 1 As shown, the control device 70 of the linkage action device specifically includes an attitude calculation unit 74, an actuator position calculation unit 75, and a teaching data storage unit 76. For example... Figure 6 As shown, when the front-side connecting rod hub 13 is taught manually or through direct teaching, the control device 70 limits the motor output and switches to torque control. When teaching the front-side connecting rod hub 13 manually or through direct teaching, direct teaching is performed with the workpiece or work object mounted on the front-end component 40, enabling high-precision positioning control. Furthermore, when the workpiece is mounted on the front-end component 40, direct teaching is performed with the work object (work object) positioned on another device side; similarly, when the work object is mounted on the front-end component 40, direct teaching is performed with the workpiece positioned on another device side.

[0092] like Figure 1 and Figure 9 As shown, when teaching the front-side connecting rod hub 13 via direct teaching, the attitude calculation unit 74 calculates the attitude of the front-side connecting rod hub 13 by positive transformation based on the position of the actuator 10, without applying preload to the parallel mechanism. The attitude of the front-side connecting rod hub 13 calculated by the attitude calculation unit 74 by positive transformation is the bending angle and rotation angle of the front-side connecting rod hub 13.

[0093] The actuator position calculation unit 75 calculates the rotational position (position) of the actuator 10 under the condition of applying preload to the parallel mechanism by inverse transformation based on the calculated attitude of the front-side connecting rod hub 13. The position of the actuator 10 calculated by inverse transformation, i.e., the inverse transformation value, is the absolute encoder 55 that detects the rotational position of the motor. Figure 5 The output value represents the amount of movement from the origin position of the front-side connecting rod hub 13, which has been pre-applied with a force that pushes the parallel mechanism in one direction.

[0094] Figure 1 The teaching data storage unit 76 stores the attitude of the front side connecting rod hub 13 and the position of the actuator 10 calculated by inverse transformation as a set of teaching data.

[0095] The control device 70 performs positioning control on the actuator 10 based on the teaching data stored in the teaching data storage unit 76.

[0096] During direct teaching, the attitude calculation unit 74 calculates the attitude (θn, φn) of the front-end connecting rod hub 13 by means of the actuator rotation position (M1n, M2n, M3n) corresponding to the rotation angle (β1n, β2n, β3n) of the end connecting rod component 15 on the base side in the unpreloaded state at the teaching position n (position n in Table 1) selected by the operator.

[0097] Specifically, the attitude (θn, φn) of the front-side connecting rod hub 13 is calculated by performing a positive transformation on equation (1) in the following relationship. Here, ε0 in equation (1) is calculated from equation (2). The rotation angle and the actuator rotation position are pre-established in a correspondence, for example, through a mapping or relational setting unit. Furthermore, the teaching position n selected during direct teaching can be only one final attitude of the front-side connecting rod hub 13, or it can include multiple attitudes from any attitude of the front-side connecting rod hub 13 to the final attitude.

[0098] [Number 1]

[0099]

[0100] The condition is that,

[0101] γ: The angle (intersection angle) between the connecting end shaft of the central connecting rod member 17 of the end connecting rod member 15, which is rotatably connected to the base end side, and the connecting end shaft of the central connecting rod member 17 of the end connecting rod member 16, which is rotatably connected to the front end side.

[0102] α: The angle between the connecting end shaft of the central connecting rod member 17, which is rotatably connected to the base end side and the front end side of the end connecting rod members 15 and 16, and the connecting end shaft of the connecting rod hubs 12 and 13, which are rotatably connected to the base end side and the front end side of the end connecting rod members 15 and 16, and the connecting end shaft of the connecting rod hubs 12 and 13, which are rotatably connected to the base end side and the front end side.

[0103] δn (n = 1, 2, 3, ...): The circumferential spacing angle between each end link member 15 on the base end side and the end link member 15 on the base end side serving as the reference.

[0104] εn (n = 1, 2, 3, ...): The circumferential angle between each rotating joint and the reference phase relative to the reference phase on the circumference traversed by the rotating joints of the end link member 15 and the central link member 17 on the base end side.

[0105] The actuator position calculation unit 75 calculates the actuator rotation position (M1n+Preload1, M2n+Preload2, M3n+Preload3) corresponding to the rotation angle of the end link component 15 on the base side under preload conditions by inverse transformation (inverse kinematics) based on the calculated attitude (θn, φn) of the front-end side connecting rod hub 13. Specifically, by performing an inverse transformation on the following relationship (1), the rotation angle βn of the end link component 15 on the base side is calculated, and the actuator rotation position (M1n+Preload1, M2n+Preload2, M3n+Preload3) corresponding to the rotation angle βn is calculated. The rotation angle βn and the actuator rotation position are pre-established with a correspondence, for example, through a mapping or relationship setting unit.

[0106] [Number 2]

[0107]

[0108] The condition is that,

[0109] γ: The angle (intersection angle) between the connecting end shaft of the central connecting rod member 17 of the end connecting rod member 15, which is rotatably connected to the base end side, and the connecting end shaft of the central connecting rod member 17 of the end connecting rod member 16, which is rotatably connected to the front end side.

[0110] α: The angle between the connecting end shaft of the central connecting rod member 17, which is rotatably connected to the base end side and the front end side of the end connecting rod members 15 and 16, and the connecting end shaft of the connecting rod hubs 12 and 13, which are rotatably connected to the base end side and the front end side of the end connecting rod members 15 and 16, and the connecting end shaft of the connecting rod hubs 12 and 13, which are rotatably connected to the base end side and the front end side.

[0111] δn (n = 1, 2, 3, ...): The circumferential spacing angle between each end link member 15 on the base end side and the end link member 15 on the base end side serving as the reference.

[0112] εn (n = 1, 2, 3, ...): The circumferential angle between each rotating joint and the reference phase relative to the reference phase on the circumference traversed by the rotating joints of the end link member 15 and the central link member 17 on the base end side.

[0113] The teaching data storage unit 76 stores the attitude (θn, φn) of the front side connecting rod hub 13 and the rotation position (M1n+Preload1, M2n+Preload2, M3n+Preload3) of the actuator as teaching data, which enables high-precision positioning control.

[0114] Figure 7 This diagram illustrates the structure of a positioning control system using a linkage mechanism 7. The control unit 70 includes, for example, a controller 71 for the linkage mechanism, drivers 77a, 77b, and 77c for each actuator, a storage device (external storage device) 78, and an input device 72. The control unit 70 is electrically connected to, for example, a personal computer 73 as an external device and a host PLC (Programmable Logic Controller) 79 as a host control device. The host PLC 79, for example, controls direct-acting actuators (not shown) synchronously with the linkage mechanism 7.

[0115] like Figure 8 As shown, the controller 71 includes a CPU 80, an internal storage area 81, an external storage device slot 82, a general communication interface 83, a display 84, a LAN interface 85, a field network interface 86, input / output interfaces (I / O), and a power supply unit.

[0116] like Figure 1 and Figure 8 As shown, the CPU 80 of the controller 71 stores the aforementioned attitude calculation unit 74 and actuator position calculation unit 75. The teach data storage unit 76 ( Figure 1 ) Stored in the internal storage area 81 of the controller 71 or as an external storage device Figure 7 In storage device 78. For example... Figure 7 and Figure 8 As shown, the storage device 78 is detachably disposed in the external storage slot 82 of the controller 71, or is communicatively connected via the general communication interface 83 of the controller 71. The teaching data is stored in at least one of the internal storage area 81 of the controller 71, the storage device 78, and the personal computer 73 as an external device.

[0117] <Flowchart for direct teaching>

[0118] Figure 10 This is a flowchart illustrating the phased processing when teaching a linkage mechanism via direct teaching. (Refer to relevant documentation for further details.) Figure 1 , Figure 7 The following explanation is provided. After the process begins, the controller 71 determines whether to select direct teaching (step S1). When the operator presses the operation button 72a on the input device 72 to indicate the start of direct teaching (step S1: Yes), the control of the actuator 10 is switched from positioning control to torque control (step S2).

[0119] In step S2, the controller 71 disables the positioning control of the actuator 10, releases the brake, or switches to torque control by limiting the output torque value of the actuator 10. Then, when the front-side connecting rod hub 13 is moved to any posture (bending angle, rotation angle) by manual operation (step S3), the process switches to step S4. In step S4, the posture calculation unit 74 calculates the current posture (bending angle θn, rotation angle φn) of the front-side connecting rod hub 13 by positive transformation (positive kinematics) based on the current rotation position (M1n, M2n, M3n) of the actuator 10 corresponding to the rotation angle of the end connecting rod component 15 on the base end side.

[0120] The actuator position calculation unit 75 calculates the actuator rotation position (M1n+Preload1, M2n+Preload2, M3n+Preload3) corresponding to the rotation angle of the end link component 15 on the base side, which takes into account the force that pushes the clearance of the parallel link mechanism 9 to one side, based on the calculated current attitude (bending angle θn, rotation angle φn) of the front-side link hub 13 through inverse transformation (inverse kinematics) (step S5). Next, the teaching data storage unit 76 stores the attitude (bending angle θn, rotation angle φn) of the front-side link hub 13 and the actuator rotation position (M1n+Preload1, M2n+Preload2, M3n+Preload3) as teaching data (step S6).

[0121] Next, the controller 71 determines whether direct teaching has ended (step S7). When the operator presses the operation button 72a on the input device 72 indicating the end of direct teaching (step S7: Yes), the actuator 10 is switched to positioning control (step S8), ending this process. If it is determined that teaching has not ended (step S7: No), the process returns to step S3.

[0122] After switching to positioning control, controller 71 uses encoder 55 ( Figure 5 The output value of the control is used for feedback control so that the rotation angle βn becomes the control target value. This enables lifting and positioning control.

[0123] <Effects>

[0124] Based on the above explanation Figure 1 The linkage mechanism 7, during direct teaching, stores the actuator position of the parallel linkage mechanism 9 under preload and the attitude of the front-side linkage hub 13 as a set of teaching data. Therefore, since the position of the actuator 10, which eliminates the influence of backlashes generated in the rotating joints and mechanism parts, can be stored as teaching data, high-precision positioning control can be achieved even during direct teaching.

[0125] According to the linkage action device 7, the front-side linkage hub 13 is configured relative to the base-side linkage hub 12 as a mechanism with two degrees of freedom in rotation and freely changeable posture. Although this two-degree-of-freedom mechanism is compact, it allows for a wide range of motion of the front-side linkage hub 13 relative to the base-side linkage hub 12. Since three or more linkage mechanisms 14 are equipped with the actuator 10, the front-side linkage hub 13 can be positioned and controlled with high precision compared to setting actuators in only two of the three linkage mechanisms 14.

[0126] <Regarding other implementation methods>

[0127] In the following description, the same reference numerals are used for parts corresponding to the matters previously described in each embodiment, and repeated descriptions are omitted. Where only a part of the structure is described, the other parts of the structure are the same as in the previously described embodiments unless otherwise specified. The same structure serves the same function. Not only can the parts specifically described in each embodiment be combined, but embodiments can also be partially combined with each other, provided that such combination does not create an obstacle.

[0128] [Second Implementation Method:] Figures 11-13 ]

[0129] like Figure 11 As shown, the base end and front end of the parallel linkage mechanism 9 can also be asymmetrical structures. For example... Figure 12 and Figure 13 As shown, on the base end side and the front end side, the distances (hereinafter referred to as "link lengths") L1A and L1B from the respective spherical link centers PA and PB to the center points C1A and C1B of each rotary joint between the end link components 15 and 16 and the central link component 17 are the same.

[0130] In contrast, the distances (hereinafter referred to as "arm lengths") L2A and L2B from the respective spherical link centers PA and PB to the center points C2A and C2B of each revolute joint between the link hubs 12 and 13 and the end link components 15 and 16 are different on the base end side and the front end side. In the second embodiment, the arm length L2A on the base end side is longer than the arm length L2B on the front end side.

[0131] Here, the center points C1A, C1B, C2A, and C2B of the rotary joint refer to the center points of the end connecting rod components 15 and 16 along the width direction of the rotary joint axes O1A, O1B, O2A, and O2B in each rotary joint.

[0132] Even if the arm lengths L2A and L2B are different on the base side and the front side, as long as the link lengths L1A and L1B are the same on the base side and the front side, then no matter what posture the parallel linkage 9 takes, the three sets of linkages 14 ( Figure 11 The base side and the front side of the ) have the same geometry.

[0133] The preferred embodiments have been described above with reference to the accompanying drawings. However, various additions, modifications, and deletions can be made without departing from the spirit of the invention. Therefore, such embodiments are also included within the scope of the invention.

[0134] Symbol Explanation

[0135] 7…Linkage Action Device

[0136] 9… Parallel linkage mechanism (parallel mechanism)

[0137] 10…Actuator

[0138] 12…base end side connecting rod hub

[0139] 13…Front-end side connecting rod hub

[0140] 14…linkage mechanism

[0141] 15…End link assembly on the base side

[0142] 16…End link assembly on the front end side

[0143] 17…Central Linkage Component

[0144] 55… Absolute Encoder

[0145] 70…control device

[0146] 71… Controller

[0147] 72…Input device

[0148] 73…External devices

[0149] 74…Attitude calculation unit

[0150] 75…Actuator position calculation unit

[0151] 76…Teaching data storage unit

[0152] 78…External storage device

[0153] 81…Internal storage area.

Claims

1. A linkage actuation device, comprising: a parallel mechanism, wherein a front-end linkage hub of the parallel mechanism is connected to a base-end linkage hub via a linkage mechanism in a manner capable of changing attitude; an actuator that changes the attitude of the front-end linkage hub; and a control device that controls the actuator, wherein... The control device has: When the attitude calculation unit teaches the front-side connecting rod hub through direct teaching, it calculates the attitude of the front-side connecting rod hub by positive transformation based on the position of the actuator without applying preload to the parallel mechanism. An actuator position calculation unit calculates the position of the actuator in the state of applying preload to the parallel mechanism by inverse transformation based on the calculated attitude of the front-side connecting rod hub. as well as The teaching data storage unit stores the attitude of the front-side connecting rod hub and the position of the actuator calculated by inverse transformation as a set of teaching data.

2. The linkage actuation device according to claim 1, wherein, The control device performs positioning control on the actuator based on the teaching data stored in the teaching data storage unit.

3. The linkage actuation device according to claim 1 or 2, wherein, The parallel mechanism connects the front-end connecting rod hub to the base-end connecting rod hub via three or more sets of linkage mechanisms in a manner that allows for attitude changes. Each linkage mechanism includes: end linkage components on the base end side and the front end side, one end of which is rotatably connected to the base end side linkage hub and the front end side linkage hub; and a central linkage component, both ends of which are rotatably connected to the other ends of these end linkage components on the base end side and the front end side. The actuator is present in all three or more of the linkage mechanisms.

4. The linkage actuation device according to claim 3, wherein, The actuator is a motor mounted on the base-side connecting rod hub. The control device drives the motor to control the attitude corresponding to the bending angle and rotation angle of the front-side connecting rod hub.

5. The linkage actuation device according to claim 4, wherein, The motor is capable of positioning control and torque control.

6. The linkage actuation device according to claim 4, wherein, When the control device teaches the front-side connecting rod hub through direct teaching, it limits the output of the motor.

7. The linkage actuation device according to claim 1 or 2, wherein, The attitude of the front-side connecting rod hub, calculated by the attitude calculation unit through positive transformation, is the bending angle and rotation angle of the front-side connecting rod hub.

8. The linkage actuation device according to claim 4, wherein, The torque of the motor is used to apply a force that pushes the gap of the parallel mechanism toward one side, thereby applying preload to the parallel mechanism.

9. The linkage actuation device according to claim 4, wherein, The force that pushes the gap of the parallel mechanism toward one side is the force that compresses the parallel mechanism in a specified direction.

10. The linkage actuation device according to claim 4, wherein, The position of the actuator calculated by the inverse transformation, i.e., the inverse transformation value, is the output value of the absolute encoder that detects the rotational position of the motor. It represents the amount of movement from the origin position of the front-side connecting rod hub, which has been pre-applied with a force that pushes the parallel mechanism in a unilateral direction.

11. The linkage actuation device according to claim 1 or 2, wherein, The teaching data is stored in the internal storage area of ​​the controller for the linkage action device, is detachably disposed in the controller or an external storage device communicatively connected to the controller, and is located in at least one of the following external devices:

12. The linkage actuation device according to claim 4, wherein, The torque of the motor that applies force in the direction that pushes the parallel mechanism to one side can be set by an input device or other external device that is electrically connected to the controller for the linkage action device.

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