Parallel link manipulator

Abstract

To provide a parallel link manipulator that has a simple structure, and is easy in handling such as moving and fixing work etc., for a work-piece even in a narrow work space or large-depth work space.SOLUTION: A parallel link manipulator comprises a base member, a movable member and a plurality of elastic strut members, and is characterized in that the plurality of elastic strut member have one-end sides fixed to the base member respectively, and also have halfway parts on the other-end sides connected independently to the movable member such that connection lengths can be variably controlled.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a manipulator composed of a parallel link mechanism for handling a workpiece, and particularly relates to a parallel link manipulator used in a narrow region of a working space.

Background Art

[0002] Manipulators composed of parallel link mechanisms are widely adopted to arrange a plurality of links in parallel, and control the movement, rotation, opening and closing of end effectors and the like. For example, Patent Document 1 discloses a manipulator for fine work that controls linear movement of a plurality of links respectively by linear actuators. Patent Document 2 discloses a fine work support system and a fine work manipulator that control the movement of each link of a parallel link having a plurality of degrees of freedom with a linear actuator. However, these techniques have a complicated structure in that linear actuators are used, and a large working area is required.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of Invention

Problems to be Solved by the Invention

[0004] The present invention has a simple structure, and an object thereof is to provide a parallel link manipulator that facilitates handling such as movement and fixing work of a workpiece even in a narrow working space or a working space with great depth.

Means for Solving the Problems

[0005] The parallel link manipulator according to the present invention comprises a base member, a movable member, and a plurality of elastic support members, wherein one end of each of the plurality of elastic support members is fixed to the base member, and the middle of the other end of each of the plurality of elastic support members is independently connected to the movable member in a manner that allows for variable control of the connecting length.

[0006] Here, an elastic support member refers to a shaft-shaped member that has spring properties and exerts a restoring force in the return direction when a load is applied in the bending direction. The present invention is characterized by the fact that, for example, one end of multiple elastic support members (such as three) is connected to a fixed member, and the other end is connected to a movable member so that the connection length between each elastic support member and the fixed member can be varied. In this way, if the connecting length of one of the three elastic support members that connect the fixed member and the movable member is made shorter than that of the other elastic support members, the other elastic support members with longer connecting lengths will bend and tilt toward the side of the shorter elastic support member. Furthermore, when the connection lengths of the three elastic support members become equal, the movable member returns to an upright position relative to the fixed member. Therefore, by varying the connection length of the three elastic support members, the XY position coordinates of the movable member relative to the fixed member can be controlled, and by varying the connection length of the three elastic support members while keeping them equal, it becomes possible to control the Z position coordinate. Here, a specific example of a configuration in which the connecting length of the elastic support member can be found in which the elastic support member has a male threaded portion formed by winding a coil spring around a core material, and the movable member has a female threaded portion. In this way, even if the core material is spring material, a screw can be easily formed using a coil spring.

[0007] In the present invention, the base member has a hand shaft that is movable upward, downward, forward, backward, and left and right, the end of the hand shaft is connected to the movable member, the tip of the hand shaft has a hand for gripping a workpiece, and the hand shaft may have an insertion part on the inside for a wire for operating the hand. In this configuration, the hand connected to the tip of the hand shaft can be controlled to move up and down, as well as to move forward, backward, and left and right. Furthermore, the gripping claws of the hand can be opened and closed by operating an operating wire located inside the hand shaft.

[0008] In the present invention, the hand shaft may be connected to the movable member by a spherical bearing. This allows for complete freedom in adjusting the connection angle between the hand axis and the movable member.

[0009] In the present invention, the hand shaft may be movable upward and downward relative to the base member and may be connected by left-right and front-back swivel joints. In this configuration, the hand shaft can move up and down relative to the base member, and can also move left and right, forward and backward, and tilt. [Effects of the Invention]

[0010] In the parallel link manipulator according to the present invention, the movable member is linked in parallel to the base member via a plurality of shaft-shaped elastic support members. By controlling the interconnection length of these plurality of elastic support members, the position coordinates of the movable member relative to the base member can be easily controlled by the bending elastic deformation of these plurality of elastic support members.

[0011] Furthermore, by combining the above-mentioned parallel link mechanism with the hand shaft, it becomes possible to control the movement of the hand located at the tip of the hand shaft, making it easier to move and fix workpieces even in narrow or deep working areas in the left-right or front-back directions. [Brief explanation of the drawing]

[0012] [Figure 1] This shows a front view of the parallel link manipulator according to the present invention. Note that the hand shaft and a portion of the elastic support member have been cut out and omitted. [Figure 2]A perspective view of the parallel link manipulator according to the present invention is shown. Note that a portion is cut and displayed in accordance with the partial omission of Figure 1. [Figure 3] (a) shows a cross-sectional view taken along line A-A of Figure 1, and (b) shows a cross-sectional view taken along line B-B of Figure 1. [Figure 4] (a) shows a cross-sectional view taken along line C-C of Figure 1, and (b) shows a cross-sectional view taken along line D-D of Figure 1. [Figure 5] A perspective view seen from the lower side near the movable member is shown. [Figure 6] (a) shows a perspective view seen from the front side near the base member, and (b) shows a perspective view seen from the rear side thereof. [Figure 7] An example of the movement of the hand shaft is shown. [Figure 8] (a) shows an example in which a coil spring is wound around a core material to form a male threaded portion, and (b) shows a cross-sectional view thereof. [Description of Embodiments for Carrying Out the Invention]

[0013] An example of the parallel link manipulator according to the present invention is shown below as an example in which link members composed of three elastic strut members 14 are arranged in parallel, but the number of the elastic strut members 14 is not limited, and the connection structure of the hand shaft 13, the movable member 12 and the base member 11 is not limited to this embodiment as long as they are mutually movable.

[0014] Figure 1 shows a front view, and Figure 2 shows a perspective view, in which a part of the middle of the three elastic strut members 14 and the hand shaft 13 is cut and displayed. Figures 3 and 4 show cross-sectional views taken along lines A-A, B-B, C-C and D-D, respectively. Figure 5 shows a perspective view near the movable member 12, and Figures 6(a) and (b) show perspective views near the base member 11. Each of the three elastic strut members 14 is in the form of a shaft having spring properties, and although not illustrated, a threaded portion is formed on the outer peripheral portion over substantially the entire length. Each of the three elastic strut members 14 is fixed at its lower end side to the base member 11 using a fastening member 14a such as a nut. The three elastic support members 14 are connected to the movable member 12 at some points. Each movable member 12 is fitted with a drive motor 16 and a drive gear 16a that is rotationally driven by the drive motor 16, corresponding to each elastic support member 14, and a driven gear 16b is gear-connected to the drive gear 16a. This driven gear 16b has a female threaded portion in its center, which is screwed into a male threaded portion formed on the outer circumference of the elastic support member 14. As a result, the driven motor drives the driven gear 16b, and as the driven gear 16b rotates, the threads of the male screw portion of the elastic support member 14 move forward. This changes the connection length of the elastic support member 14 between the base member 11 and the movable member 12. Here, instead of directly threading the outer circumference of the shaft-shaped elastic support member 14, a coil spring 14c may be wound around a springy core material 14b to form the threaded portion, as shown in Figure 8. In this case, a female threaded portion 16c is formed at the center of the driven gear 16b to advance the coil spring 14c. Furthermore, the ends of the coil springs are fixed to the core material 14b with push nuts 14d.

[0015] Next, an example of a connection structure between the hand shaft 13, the movable member 12, and the base member 11 will be described. As shown in Figure 5, the hand shaft 13 is connected to a ball portion 18a as an inner ring, and the ball portion 18a and the spherical outer ring 18 are connected to each other in a spherical bearing structure that allows them to rotate freely. As shown in Figures 4 and 6, the hand shaft 13 and the base member 11 are connected by a shaft coupling mechanism between the housing 17 and the hand shaft side housing 17a, with pivot axes 117a and 117d in the front-rear direction and pivot axes 117b and 117c in the left-right direction, so that the hand shaft 13 is connected to the base member 11 so as to be rotatable left-right and front-rear.

[0016] As shown in Figure 4, the hand shaft 13 is connected along the hand shaft side housing 17a so that it can move downward and upward. In this embodiment, the parallel link manipulator is described as being positioned vertically, but there are no restrictions on the positioning direction, such as horizontal or diagonal. As shown in Figure 6(a), a position detection sensor 21 is attached to control the position in which the hand 15, which is located at the tip of the hand shaft 13, moves downward or upward. In this example, the amount of movement of the hand shaft 13 is detected by the roller 21b and the position sensor 21a which detects the movement of the roller 21a. Furthermore, as shown in Figure 6(b), a front-to-back angle sensor 17b for detecting the tilt of the hand axis 13 in the front-to-back direction and a left-to-right angle sensor 17c for detecting the tilt of the hand axis 13 in the left-to-right direction are attached.

[0017] A hand 15 is attached to the tip of the hand shaft 13 via a connecting member 15b so as to be rotatable in the front-rear direction. In this embodiment, the hand 15 has a pair of gripping claws 15a, 15a that are controlled to open and close for gripping a workpiece. To operate the rotation of the hand 15 and the opening and closing of the gripping claws 15a, 15a, a wire insertion section is formed inside the hand shaft 13, as shown in Figure 3. Multiple wires 15c are connected to an operating section (not shown) via the upper end of the hand shaft 13, as shown in Figure 1.

[0018] With the above structure, the parallel link manipulator according to the present invention, as shown in Figure 7 for example, can control the upward and downward movement of the hand 15, as well as the left-right and forward-backward movement, by varying the interconnection length of the three elastic support members 14 through the drive control of three drive motors. [Explanation of Symbols]

[0019] 11 Base member 12 Movable members 13 Hand Axis 14 Elastic support member 15 Hand 15a Gripping claw 15b Hand connecting member 16 Drive motor 16a Drive gear 16b Driven gear 17. Shaft coupling 18 Spherical bearings

Claims

1. It comprises a base member, a movable member, and a plurality of elastic support members. Each of the plurality of elastic support members is fixed to the base member. Each of the aforementioned plurality of elastic support members is independently connected to the movable member in such a way that the connection length can be variably controlled. A parallel link manipulator characterized in that the elastic support member has a coil spring wound around a core material and has a male threaded portion, and the movable member has a female threaded portion.

2. The parallel link manipulator according to claim 1, characterized in that the base member has a hand shaft that is capable of moving upward, downward, forward, backward, and left and right, and the end of the hand shaft is connected to the movable member.

3. The parallel link manipulator according to claim 2, characterized in that the hand shaft has a hand for gripping a workpiece at its tip, and the hand shaft has an internal portion for inserting a wire for operating the hand.

4. The parallel link manipulator according to claim 2, characterized in that the hand shaft is connected to the movable member by a spherical bearing.

5. The parallel link manipulator according to claim 4, characterized in that the hand shaft is movable upward and downward relative to the base member and is connected by left-right and front-back flexible shaft joints.

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