JPH0890462A - Parallel link manipulator - Google Patents

Abstract

(57) [Summary] [Purpose] You can effectively use an on-site work space that is not isotropic,
It also provides a manipulator mechanism that is easy to divide and reassemble and has excellent portability. [Structure] One end of a plurality of links is connected to a moving block via a joint having multiple rotational degrees of freedom, and a hand effector is attached to the other end of the link via a joint having multiple rotational degrees of freedom. In the parallel link manipulator, one of the surfaces on which the moving block is placed is used as a reference surface of a three-dimensional polyhedron including the link, the moving block, and the hand effector, and a plane (fixed plate) parallel to the reference surface. By linearly moving the block, the three-dimensional movement control and the three-dimensional posture control of the hand effector are performed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a parallel link manipulator which, like an industrial robot or the like, handles a work piece with high precision and can be operated remotely and / or automatically, and particularly in a narrow space. Involved in automated equipment for handling things.

[0002]

2. Description of the Related Art In handling heavy objects, Japanese Patent Laid-Open No. 58-77466 and Japanese Patent Laid-Open No. 61-109682.
The technique using a lifting machine and a general-purpose robot as disclosed in Japanese Patent Publication is known in the prior art. However, in this technology, since it is assumed that a load balancer or the like is used, the equipment installation space is large, and because the load balancer and the like are not a high-performance system for control, high position accuracy and attitude accuracy are required. Hard to get.

A parallel link mechanism is a multi-degree-of-freedom control mechanism which is good at handling heavy objects. There are roughly two types of parallel link mechanisms,
One is a rotary joint type, and the other is a linear joint type. The linear drive is more suitable for high output than the joint rotary drive shown in the literature (Journal of the Robotics Society of Japan, Vol. 10, No. 6, p. 35) because the reaction force can be supported by the axial force instead of the joint torque. The Stuart platform is a typical example of this linear drive. Further, as a conventional technique in which this parallel link mechanism is devised and improved, for example, Japanese Patent Laid-Open No. 63-
The technique described in Japanese Patent No. 150178 is well known, and according to this conventional technique, as shown in FIG.
With the actuator attached to the hand effector 1
Since 0 can be driven in any direction, it has the advantages of simple structure and easy assembly. Further, as an improved version of this, the technique described in Japanese Patent Laid-Open No. 2-311284 shown in FIG. 5 is well known, and according to this technique, it is released from the control while associating each individual actuator, It has the advantage of requiring mechanically simple calculation processing.

[0004]

However, when these techniques are applied on site to handle heavy objects,
A major problem is space competition with existing equipment. In an actual site, it is difficult to take a cubic isotropic work space in a mechanical device, and there is space in the length direction,
In most cases, only equipment in a narrow space such as a very narrow width is allowed, and it is often difficult to apply the equipment of the above technology.

In a direct acting joint type parallel link suitable for handling heavy objects, a moving direction of an actuator to be driven requires a particularly space. That is, it is desirable to control the movement of the hand effector by taking the movement direction of the actuator in the longitudinal direction of the elongated space permitted for field application. In addition, portability is also important to use for maintenance work, etc.If all the actuators are mounted on the fixed plate and divided at the link part to reduce the weight of each one and carry it, and it is easy to reassemble on site, it is very important. This requirement is strong in practice because it is easy to use.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a parallel link manipulator for handling heavy objects, which is capable of effectively utilizing an on-site space which is not isotropic and which is excellent in portability. To do.

[0007]

In order to achieve the above object, the present invention is to connect one end of a plurality of links to a moving block through a joint having multiple rotational degrees of freedom, and to connect the other end of the links. In a parallel link manipulator in which a hand effector is attached via a joint having multiple rotational degrees of freedom, one of the surfaces on which the moving block is placed is a solid polyhedron composed of the link, the moving block, and the hand effector. As a reference plane of, a plane parallel to the reference plane (fixed plate)
Move the moving block linearly within the 3
Dimensional movement control and three-dimensional posture control are performed, and in the above manipulator, the movement directions of all the movement blocks are movements on lines parallel to each other. Further, in the above manipulator, , The total number of links is 4, two of them are trapezoidal links, and the moving blocks are synchronously moved in the opposite direction, and the number of degrees of freedom of rotation of the joint of each link is 2 The direction is the rotation direction of an axis parallel to the moving direction of the moving block that moves on the parallel line placed on the fixed plate, and the direction of the other degree of freedom of rotation is the direction perpendicular to the first rotation axis. , Controlling the two-dimensional position and orientation of the hand effector in a plane orthogonal to the moving direction of the moving block.

[0008]

According to the present invention, as shown in FIG. 1, basically, one end of each of the six links 2a to 2f is rotatably coupled to the moving block 1a to 1f and the other links are connected to each other. Since the end is rotatably coupled to the hand effector 10, by controlling the positions of the moving blocks 1a to 1f in the direction of the xy plane, 6 degrees of freedom (x, y) of the three-dimensional space of the hand effector are controlled. , Z position and rotation around each axis) can be arbitrarily controlled. Furthermore, since the driving actuators are all mounted on the fixed plate 11,
The division / reassembly at the links 2a to 2f can be performed without removing the actuator.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a skeleton model of a six-degree-of-freedom control parallel link manipulator according to the present invention. In this embodiment, joints (for example, spherical bearings) 3a to 3f capable of rotating three axes are provided at both ends of the six links 2a to 2f, the upper ends thereof are respectively connected to the moving blocks 1a to 1f, and the lower ends thereof are end effectors. 10 is connected to the finger effector by setting the attachment position so that all the links are not parallel (when all the links are parallel, the movement in the orthogonal direction is uncontrollable, a so-called peculiar state) become). In this mechanism, when the desired position (x, y, z) and posture (rotational angle of each axis) of the hand effector are given, the three-degree-of-freedom joints 3a to 3f fixedly arranged on the hand effector 10 are provided. The spatial coordinates are uniquely determined, and the positions of the moving blocks 1a to 1f at the upper end are obtained as follows from the length of the links 2a to 2f with this point as the center.

[0011] coordinates X _3a of the three degrees of freedom joints 3a on the end effector 10, and Y _3a, Z _3a, coordinates X _1a of the movable block 1a joints, Y _1a, the length of the Z _1a link 2a l _{a Then, l a = {(X 1a} -X 3a) 2 + (Y 1a -Y 3a) 2 + (Z 1a -Z 3a) 2} 1/2 ... (1) where the movement of the upper fixing plate 11 If the moving direction of the block 1a (the laying direction of the slide rail) is parallel to the X axis,
Since Y _1a and Z _1a is a constant variable is only the _{X 1a, X 1a = ± {} l a 2 - (Y 1a -Y 3a) 2 - (Z 1a -Z 3a) 2} 1/2 + X 3a ... (2) The ± sign is selected according to the sign of the initial state of X _1a (preventing the structural state from jumping over 0).

Similarly, X of the moving blocks 1a-1f
The coordinates are also required. If the movement blocks 1a to 1f are position-controlled to the X-coordinate value obtained in this way by using a driving device and a control device (not shown), the hand effector 10 can be moved to any position and posture. It can act as a manipulator with.

In the present embodiment, when the whole mechanism is viewed geometrically, a three-dimensional polyhedron composed of the links 2a to 2f and the hand effector 10 is formed with the surface on which the moving blocks 1a to 1f are placed as a reference surface. There are moving blocks 1a-1f
By setting the moving direction of the device to be in a plane parallel to the reference plane and parallel to the X-axis direction, the installation space of the equipment is long in the X-axis direction but small in the Y-axis direction. Therefore, it is possible to match the installation space at a site that is not isotropic.

Further, all the driving devices are mounted on the fixed plate 11 side, and the links 2a to 2f or the three-degree-of-freedom joints 3a to 3f are members that simply transmit force, so that they can be easily disassembled and assembled. In the movement of the parallel link manipulator device, the fixing plate 11 on which a set of drive device is mounted and the links 2a to 2f can be easily performed.
As a result, the hand effector 10 can be disassembled (or the hand effector 10 can be disassembled), the weight and size of the single part can be reduced, and the carry-in / carry-out to the use site is very easy.

In this embodiment, the joints at both ends of the links 2a to 2f are both joints having three degrees of freedom in order to facilitate the description, but strictly speaking, it is sufficient that both ends have five degrees of freedom (links). The rotation of its own axis does not change the position or posture of the hand effector 10 and is a wasteful degree of freedom.) If the joint on the lower end side has three degrees of freedom, the joint on the upper end side has two degrees of freedom.
Good.

Next, FIG. 2 shows a skeleton model of a three-degree-of-freedom control parallel link manipulator according to the present invention. In this embodiment, two links (for example, gimbals) 4a-4d capable of biaxial rotation are provided at both ends of the four links 2a-2d, and the upper ends thereof are movable blocks 1a-1d.
, And the lower end is connected to the finger effector 10 by setting the attachment position to the finger effector so that all the links are not parallel. Two free joints 4a
The first rotation axis direction of ~ 4d is the X-axis direction in the figure,
The second rotation axis direction is the orthogonal direction, that is, the direction parallel to the YZ plane.

With this configuration, the moving blocks 1a to 1d are controlled in the same manner as in the first embodiment described above, but the moving blocks 1a and 1b are moved in the opposite directions by the same amount in synchronization with each other by one driving mechanism. Since the links 2a and 2b have the same size, the fixed plate 11, the links 2a and 2b, and the hand effector 10 form a symmetrical trapezoidal link structure, and the X-axis of the hand effector 10 is formed. The hand movement effector 10 is supported by restraining the directional movement and the Y-axis rotation. In addition, the shaft joints 4a to 4d attached to the links 2a to 2d are
Since only the axial rotation and the Y-axis rotation are allowed, the Z-axis rotation of the hand effector 10 is restricted. After all, in the present mechanism, by controlling the movement of the movement blocks 1a to 1d in the X direction, the position control (Y, Z) and the posture control (X axis) of the hand effector 10 in the YZ plane in the orthogonal direction are controlled. It becomes a parallel link manipulator that can control three degrees of freedom (rotation). The two-degree-of-freedom rotary joints 4d and 4c are arranged so that the line connecting the centers of rotation of the second axes is parallel to the Y-axis (preferably, the two-degree-of-freedom rotary joint 4 for generating a trapezoidal link).
When placed on the bisector of a and 4b), the hand effector 10
The posture rotation axis can be aligned with the X-axis direction, and control is facilitated.

In the maintenance work of rotary drive shafts such as rolling mills and pinch rolls in the steelmaking work, the line direction (X
Direction) is a fixed position, and the handling of the rotary drive shaft is required only by moving in the axial direction (Y direction), moving in the gravity direction (Z direction), and adjusting the posture (X axis rotation) within the plane. In many cases, maintenance such as disassembly and assembly of machines can be performed, and other degrees of freedom of manipulators are often unnecessary. In addition, the space between the pinch roll drive motor and the pinch rolls (Y direction) is narrow as a work space, and there are often restrictions on the dimensional arrangement of the manipulators in space. The mechanism is optimal.

In the present embodiment, as shown in FIG. 3, the link 2c and / or the link 2d have a parallel link structure so that the parallel rigidity between the fixing plate 11 and the hand effector 10 is increased to improve the rigidity of each link. It is also effective to reduce the axial force load, and it is also effective to increase the overall rigidity by setting two or more trapezoidal link configurations.

Further, in using these parallel link manipulators, it is possible to predetermine a motion locus and reproduce the locus on site like a normal robot operation, or to operate the manipulator by remote operation on the site. May be.

[0021]

As described above, according to the present invention, one end of a plurality of links is connected to a movable block through a joint having a rotary multi-degree of freedom, and the other end of the link has a multi-rotational degree of freedom. The finger effector is attached through a joint, and the surface on which the moving block is placed is used as a reference surface of a solid polyhedron composed of the link, the moving block, and the finger effector, and the movement is performed in a plane parallel to the reference surface. Three-dimensional movement control of the hand effector by linearly moving the block,
Also, it is a parallel link manipulator capable of three-dimensional attitude control. Furthermore, depending on the application, the required degree of freedom can be reduced and the number of components can be reduced, enabling the handling of heavy objects in a narrow space on site or automatically, and also for dividing and assembling. Since it is easy, it is also highly portable, and high-precision handling can be performed while controlling the posture of the object, which was not possible with handling with a hoist or load balancer, so work efficiency is dramatically improved and work safety is also improved. It has a great effect.

[Brief description of drawings]

FIG. 1 is a diagram showing an overall configuration of the present invention.

FIG. 2 is a diagram showing an overall configuration of another embodiment of the present invention.

FIG. 3 is a diagram showing another aspect of the link in the present invention.

FIG. 4 is a diagram showing a conventional technique.

FIG. 5 is a diagram showing another conventional technique.

[Explanation of symbols]

 1 Moving block 2 Link 3 Three-degree-of-freedom rotary joint 4 Two-degree-of-freedom rotary joint 10 Hand effector 11 Fixed plate

Claims (3)

[Claims] 1. One end of a plurality of links is coupled to a moving block via a joint having multiple rotational degrees of freedom, and a hand effector is connected to the other end of the link via a joint having multiple rotational degrees of freedom. In the attached parallel link manipulator, one of the surfaces on which the moving block is placed is used as a reference surface of a three-dimensional polyhedron composed of the link, the moving block, and the hand effector (a fixed plate). The parallel link manipulator is characterized in that the moving block is linearly moved in (3) to perform three-dimensional movement control and three-dimensional posture control of the hand effector. 2. The parallel link manipulator according to claim 1, wherein the moving directions of all the moving blocks are movements on lines parallel to each other. 3. The parallel link manipulator according to claim 2, wherein the total number of links is four, and two of them have a trapezoidal link structure to move the moving blocks synchronously in opposite directions and to freely rotate a joint of each link. Frequency 2
Is the direction of one rotational degree of freedom of the joint is the rotational direction of an axis parallel to the moving direction of the moving block moving on the parallel line placed on the fixed plate, and the other rotational degree of freedom is A parallel link manipulator for controlling a two-dimensional position and orientation of the hand effector in a plane orthogonal to the moving direction of the moving block as a direction perpendicular to the first rotation axis.