JP2588418B2 - 3D manipulator - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a three-dimensional manipulator capable of moving an end effector three-dimensionally.

[Conventional technology]

Various types of multi-dimensional manipulators that can be moved two-dimensionally or three-dimensionally have already been proposed, and many technologies are used particularly in the field of industrial robots and the like. However, if multi-dimensional positioning is to be performed with high accuracy, the complexity and cost of the apparatus are unavoidable. Therefore, the work side is often moved by an XY table to perform relative positioning with respect to the end effector. As such a drive control method for the XY table, there is, for example, a method disclosed in JP-A-62-179004.

[Problems to be solved by the invention]

However, driving control of the XY table is not easy, and complicated control must be performed. X-
The Y table has a problem that its size is considerably large and bulky. Therefore, development of a multidimensional manipulator that is compact and inexpensive and has high positioning accuracy has been desired.

[Object of the invention]

An object of the present invention is to provide a three-dimensional manipulator that is compact, inexpensive, and has high positioning accuracy, with a view to solving the above-mentioned problems in the prior art.

[Means for solving the problem]

In order to achieve the above object, in the three-dimensional manipulator of the present invention, three arms are respectively rotatably attached to three movable bodies which are respectively movable on a plurality of one-dimensional guide members. Arms are rotatably connected to each other at predetermined connecting portions to form a link mechanism, and three driving means for driving each of the three moving bodies to move independently on each of the one-dimensional guide members. And an end effector is connected to the link mechanism.

[Action]

When the three moving bodies are moved in the same direction, the link mechanism moves in the same direction as the direction in which the guide member extends as a whole without changing its joint angle. Thus, the end effector can move in the same direction as the above direction. On the other hand, when a plurality of moving bodies are moved in different directions, the joint angle in the link mechanism changes.
Because the length of the arm is fixed, this causes the end effector to move in a direction that is non-parallel to the direction in which the guide member extends. By combining these movements, it is possible to move and position the end effector three-dimensionally.

〔Example〕

First, a proposed example of a two-dimensional manipulator having a structure related to the present invention will be described. That is, FIG.
FIG. 4 is a perspective view of a part of the two-dimensional manipulator, which is partially cut away. The manipulator 1 has a guide member 2 that extends one-dimensionally in the X direction. The guide member 2 includes a pair of guide rails 3 a and 3 b parallel to each other and a screw rod 4. These guide rails 3a, 3b have a pair of moving bodies 5a,
5b is slidably mounted. The moving bodies 5a and 5b are supported by the guide rails 3a and 3b, and their movement in the X direction is guided by the guide rails 3a and 3b.

Motors 6a, 6b are attached to the moving bodies 5a, 5b, respectively. These motors 6a and 6b are, for example, brushless servomotors, and have a built-in ball nut (not shown) formed integrally with the motor rotor. The ball nut is screwed with the screw rod 4, and the ball nut and the screw rod 4 form a ball screw. For this reason, the power is supplied to the motors 6a and 6b through respective power supply lines (not shown), thereby generating a rotational force on the motors 6a and 6b, whereby the moving bodies 5a and 5b are independently driven in the X direction or the (-X) direction. Moving. Note that a rotary encoder for detecting a rotor rotation angle can be provided in each of the motors 6a and 6b.

Arms 8a and 8b are rotatably supported on the moving body 5a and 5b on the XY plane by rotating mechanisms 7a and 7b formed by cross roller bearings or the like. For this reason, the arms 8a and 8b are pivotable in the XY plane.
Although the lengths of the arms 8a and 8b may be different from each other, they are the same length L (not shown in FIG. 1) in this proposal.

The other ends of the arms 8a and 8b are connected to each other via a rotating mechanism 9 formed of a cross roller bearing or the like.
-It is rotatably connected in the Y plane. Therefore, the arms 8a and 8b form a link mechanism 10 having their ends as connecting portions. An end effector 11 constituted by an air chuck is attached to an end of one arm 8b below the connection portion. This air check is opened and closed by air supplied through the air hose 12.

Next, a basic operation of the manipulator 1 will be described. Here, reference is made to FIG. 2 which schematically shows the mechanism of FIG. 1 as an XY plan view. However, in FIG. 2, X = Xa, Xb is assumed as the reference position of the moving bodies 5a, 5b on the guide member 2, respectively.

First, when the moving bodies 5a and 5b are both moved by the same amount in the X direction (FIG. 2 (a)), the joint angle θ of the link mechanism 10 remains unchanged and the link mechanism 10 Translate in the direction (dashed line). For this reason, the end effector
The Y coordinate Y _{0 of} 11 remains unchanged, and its X coordinate changes to the (+) side. Conversely, mobile 5a, is moved by the same amount and 5b in (-X) direction, while keeping unchanged the Y coordinate Y _0, the end effector 11 is moved to the (-X) side (FIG. 2 ( a) Solid line).

On the other hand, when the moving bodies 5a and 5b are moved by the same amount in opposite directions (FIG. 2 (b)), the joint angle θ of the link mechanism 10 changes while the X-directional center of gravity of the link mechanism 10 remains unchanged. Therefore, if the moving bodies 5a and 5b move so as to approach each other, the Y coordinate of the end effector 11 increases as shown by a broken line, and the moving bodies 5a and 5b move in a direction away from each other. For example, as shown by the solid line,
Eleven Y coordinates decrease. In these, the Y coordinate X ₀ of the end effector 11 is unchanged.

From these facts, by controlling the moving direction and moving amount of each of the moving bodies 5a and 5b, the end effector
It can be seen that 11 can move arbitrarily in a right-angle two-dimensional XY plane. The movable range is a rectangular area A surrounded by a broken line in FIG. 2 (c). The lengths of the upper side and the lower side of the rectangular area A are mainly defined by the length of the guide member 2, and the left side and the right side Is mainly determined by the length L of the arms 8a and 8b.

The end effector 11 is set to an arbitrary point (Xc, Yc) in the area A.
The position to which the moving bodies 5a and 5b should be moved when positioning is determined by a simple geometric calculation. For the purpose of facilitating understanding, consider a case where an approximation that ignores the size of the moving objects 5a and 5b itself is performed. In this case, as shown in FIG. 2 (c), assuming a circle C centered on the point (Xc, Yc) and having a radius of the length L of the arms 8a, 8b, this circle C is The X coordinates X ₁ and X ₂ of two points intersecting with the line segment 1 representing the member 2 are obtained. And these X coordinates X ₁ , X ₂
The moving bodies 5a and 5b may be moved to the positions of. Extension to the case where the size of the moving bodies 5a and 5b themselves is considered is also easy. Therefore, when a controller (not shown) for controlling the manipulator 1 is provided, the control sequence in the controller is relatively simple.

As described above, in the manipulator 1 of the proposed example,
Since the end effector 11 can be moved two-dimensionally only by a mechanism that drives the moving bodies 5a and 5b in one-dimensional translation, it is mechanically compact. In addition, since the number of expensive ball screws and the like required for precise positioning can be reduced, the manipulator 1 can be configured relatively inexpensively. In particular, this effect is further enhanced by using an integrated motor with a built-in nut as the motors 6a and 6b. Furthermore, since it is mechanically simple, there is little positioning error due to deformation of each part or play of the movable part, etc.
High-precision positioning becomes possible.

Next, a three-dimensional manipulator according to an embodiment of the present invention will be described. The same components as the members in the above-mentioned proposal example are denoted by the same reference numerals, and detailed description thereof will be omitted.

That is, as shown in FIG. 3A, one-dimensional guide members 2a to 2c having a structure corresponding to the proposed member 2 are provided in parallel with each other. Then, three moving bodies 5A to 5C having structures corresponding to the moving bodies 5a and 5b are movably attached to these guide members 2a to 2c, respectively, and the arms 8a and 8b are attached to the moving bodies 5A to 5C.
The three arms 8A to 8C having a structure corresponding to are supported rotatably.

Each of the arms 8A to 8C forms a link mechanism 10a having the other end as a connecting portion, and the end effector 11 is attached below the connecting portion.

With this configuration, the end effector 11 can move in a three-dimensional space defined by an XYZ rectangular coordinate system by controlling the moving direction and the moving amount of each of the moving bodies 5A to 5C. It is. Note that, at this time, any two of the guide members 2a to 2c may be shared with each other. However, in the case of such a three-dimensional manipulator, each rotating unit is configured to be rotatable within a predetermined solid angle. Also,
The end effector 11 is always in a predetermined direction (for example, downward)
To face.

FIG. 3B is a schematic diagram illustrating an example of the configuration of FIG. 3A. In this example, each of the arms 8A to 8C is formed by a parallel link mechanism. By fixing the shaft 11a of the end effector 11 to the vertical side 8a of the arm 8A, the end effector 11 always faces downward. Only the arm 8A may have a parallel link configuration.

Further, in the above embodiment, as in the proposed example, a structure in which the ball nut is rotated by a motor attached to the moving bodies 5A to 5C may be used.When a screw rod is provided for each of the moving bodies 5A to 5C, the guide member 2a A structure may be adopted in which a motor is provided on the side of .about.2c to rotate those screw rods. However,
It is desirable that the structure in which the ball nut is rotated by the motor attached to the moving bodies 5A to 5C is also the simplest in terms of mechanism, and also serves as a screw rod.

Therefore, similarly to the above-mentioned proposal example, the end effector 11 is controlled by only the mechanism for controlling the moving bodies 5A to 5B in a one-dimensional manner.
Since it can be moved dimensionally, it is mechanically compact. In addition, the number of expensive ball screws and the like required for precise positioning can be reduced, and the manipulator can be configured relatively inexpensively. In particular, this effect is further enhanced by using a nut-integrated motor as a motor. Furthermore, since it is mechanically simple, there is little positioning error due to deformation of each part or play of the movable part, and high-precision positioning is possible.

It should be noted that the three-dimensional manipulator of the present invention uses a conventional X-
In addition to the field of performing positioning using a Y table, the present invention can be used for various handling systems and processing systems.

〔The invention's effect〕

As described above, according to the present invention, three-dimensional positioning of the end effector becomes possible by independently moving each moving body on each one-dimensional guide member, and is mechanically compact, inexpensive, and high in cost. A three-dimensional manipulator suitable for accurate positioning can be obtained.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a principal part of a proposed example related to the present invention, FIG. 2 is a schematic plan view showing the operation principle of the proposed example, and FIG. 3A is an explanatory view of an embodiment of the present invention. FIG. 3B is a schematic diagram illustrating an example of the manipulator of FIG. 3A. 2a, 2b, 2c …… Guide members 5A, 5B, 5C …… Moving body 8A, 8B, 8C …… Arm 10a …… Link mechanism 11 …… End effector

Claims (1)

(57) [Claims] An arm is rotatably mounted on each of three movable members movable on a plurality of one-dimensional guide members, and the three arms are rotatable relative to each other at a predetermined connection portion. And a link mechanism is formed, and three driving means are provided for driving each of the three moving bodies and independently moving on each of the one-dimensional guide members, and an end effector is provided on the link mechanism. Are connected to the three-dimensional manipulator.