JPS6347081A - Manipulator - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a manipulator having a plurality of hinges, and more particularly to a manipulator having a vibration-absorbing hinge.

(Prior Art) In recent years, manipulators including industrial robots have become rapidly popular and are used in various fields. Most of this type of manipulator has a cantilever structure, and even the slightest disturbance causes the arm to vibrate, which affects operational performance. That is, the tip of the cantilever beam is often operated, and this part is affected by cumulative vibrations of each arm and errors in the hinge angle, resulting in a significant drop in operational performance.

For these reasons, when designing a manipulator, a method is often taken to increase the rigidity of each part, but this increases the weight of the manipulator. Moreover, considering that manipulators will be applied to space exploration in the future, weight reduction will become a very important issue, and it is expected that efforts will be made to reduce weight even if elastic deformation is allowed. Therefore, it is necessary to fully consider the problem of vibration suppression.

By the way, the conventional method for arranging the hinge of a manipulator is
Most methods consider the manipulator as a rigid body, first place a hinge to determine the position of the tip, and then place a hinge to determine the posture of the tip, and add redundant systems as necessary. The position and posture can be changed arbitrarily along the way.

This will be explained with reference to FIG. FIG. 3 shows an example of the arrangement of each hinge of the rigid body manipulator. 1 in the figure. ~, 6 is a hinge, 7°8 is an arm, and 9 is a hand. Since the manipulator performs work with the hand 9 attached to its tip, it is necessary to bring the hand 9 to any point in space and to be able to take any posture there in order to improve the workability of the manipulator.

In order to bring the tip of the manipulator to an arbitrary position in three-dimensional space, at least three degrees of freedom are required, so first, the position is determined using the first three degrees of freedom counting from the base. At this time, in order to make the reachable area as wide as possible, first place the hinge 1 with the axis of rotation in the longitudinal direction of the arm.

After this, hinges 2 and 3 having rotation axes perpendicular to the plane of the paper are placed second and third so that arbitrary positioning within a plane including the hinge 1 is possible.

Now that we have positioned the hand 9, we need to determine its posture, but in order to take the desired posture, we need to
Freedom is necessary. Therefore, by arranging the hinges 4, 5, and 6, it has 6 degrees of freedom as a whole,
The position and posture of the hand 9 can be determined.

However, this arrangement is only effective for a manipulator that is a rigid body, and a manipulator that is a flexible structure has the following problems. That is, in the manipulator as a flexible structure, the arm 7.
For example, when torsional vibration occurs in the arm 7, the hand 9 vibrates with the axial direction of the arm 7 as the rotation axis. In this case, it becomes very difficult to determine the posture with respect to the direction of motion of the vibration, resulting in a problem that the positioning performance of the manipulator is degraded.

(Problems to be Solved by the Invention) As described above, in the conventional manipulator, when an attempt is made to reduce the overall weight, bending vibration, torsional vibration, etc. occur in the arm. When these vibrations occur, it becomes difficult to quickly and accurately control the position and posture, resulting in a decline in positioning performance.

The present invention has been made in consideration of the above circumstances, and its purpose is to provide a manipulator that can suppress vibrations generated in the arm and improve positioning performance.

[Structure of the Invention] (Means for Solving the Problems) The present invention provides a manipulator in which a plurality of arms are connected by hinges and constitutes a spatial link mechanism as a whole. In addition to a positioning hinge arranged to determine the position and orientation of the arm, a vibration absorbing hinge is arranged to absorb vibrations generated in the arm.

The method of arranging the hinge according to the present invention is as follows.

First, a structure is considered to be a rigid body, and a necessary number of positioning hinges are placed at necessary locations so that any point on the structure can take a desired position and orientation. If we focus only on the position and posture of the tip of the structure, then 6
If one positioning hinge is arranged and the posture of the entire structure is also considered, the number of positioning hinges is increased as necessary.

After placing the hinge on the structure as a rigid body,
Next, vibration-absorbing hinges that are movable in the direction in which each member of the structure is deformed by vibrations generated in the structure are placed at appropriate positions on each member. By doing so, the position and orientation of the tip of the structure or the entire space can be freely determined using the positioning hinge. Furthermore, vibrations generated in the structure can be suppressed by providing the vibration-absorbing hinge with a damper function. However, depending on the direction of vibration, it is also possible to use a positioning hinge to suppress vibration.

(Function) With the above configuration, vibration generated in any arm can be suppressed by the vibration absorbing hinge corresponding to the vibration direction. Therefore, it becomes possible to position each arm quickly and accurately. Furthermore, since the vibration-absorbing hinge can serve as a redundant system for posture determination, it is also possible to improve the positioning function.

(Example) Hereinafter, details of the present invention will be explained with reference to illustrated embodiments.

FIG. 1 is a schematic configuration diagram showing a manipulator according to an embodiment of the present invention. 1 in the figure. -, 6 are positioning hinges, 7 and 8 are arms, 9 is a hand, and 10, -, 13 are vibration absorbing hinges.

In order to accurately arrange the hinges for the manipulator as a flexible structure, we first perform the hinge arrangement for the rigid manipulator. Since the manipulator performs work with the hand 9 attached to its tip, it is necessary to bring the hand 9 to any point in space and to be able to take any posture there in order to improve the workability of the manipulator. Therefore, in order to determine the position and orientation of the hand 9 of the manipulator, the positioning hinge 1. ~, 6 are placed. Among these, hinge 1. . . . , 3 are for position determination, and the hinges 4. to 3 are for position determination. ~, 6 is for attitude determination at that point.

Now that the hinge arrangement for the rigid body manipulator has been completed, the next step is to arrange the hinges necessary for vibration suppression. Here, we will consider vibrations occurring in arm 7.8. The directional components of the generated vibrations are bending vibrations in planes parallel to and perpendicular to the plane of the paper and torsional vibrations of the arm. Among these, the bending vibration in the plane of the paper can be suppressed by the positioning hinges 2 and 3, so the vibration absorbing hinge 10.
Place 12. Furthermore, vibration absorbing hinges 11 and 13 are arranged to deal with torsional vibration.

The vibration absorbing hinges 10 and 11 are arranged on the proximal end side of the arm 7, and the vibration absorbing hinges 12 and 13 are arranged on the proximal end side of the arm 8. Also, these hinges 1
0. A drive control system is connected to each of the hinges 1 to 13, and each hinge is driven by an actuator or the like according to the amount of vibration to be canceled.

Here, the drive control system for the hinge 11 is composed of displacement meters 21a, 21b, a vibration detector 22, an amplifier 23, an actuator 24, etc., as shown in FIG. 2, for example.

The displacement meters 218 and 21b are arranged on the base end side and the distal end side of the arm 7, and detect the amount of displacement of the arm 7 around the axis, respectively. Each detection output of the displacement meters 21a and 21b is supplied to a vibration detector 22. The vibration detector 22 detects torsional vibration of the arm 7 by taking the difference between the detection outputs. A signal corresponding to the detected torsional vibration is sent to amplifier 2.
3 and then supplied to the actuator 24. Then, by the actuator 24, the hinge 11
is driven. In other words, the hinge 11 is driven to cancel the torsional vibration of the arm 7, thereby suppressing the torsional vibration. Further, the drive control system for the other hinges is similarly composed of a displacement meter, a vibration detector, an actuator, and the like.

With such a configuration, the positioning hinges 1° to 6
By the action of the arm 7.8, the arm 7.8 can be moved in any direction and the hand 9 can be positioned at a predetermined position.
The attitude of the person can be determined. And arm 7.8
When bending vibration or torsional vibration occurs, the deformation of the arm due to this vibration is absorbed by the vibration absorbing hinge 10. ~, 13
It can be canceled by the action of Therefore, even if the manipulator is a flexible structure designed to be lightweight, vibration generated in the arm can be suppressed, and positioning performance can be improved.

In addition, since the hinge for vibration absorption can serve as a redundant system for posture determination, it is also possible to improve the positioning function of the manipulator.

Note that the present invention is not limited to the embodiments described above, and can be implemented with various modifications without departing from the gist thereof. For example, the arrangement example of the positioning and vibration absorbing hinges is not limited to that shown in FIG. 1, and can be changed as appropriate according to specifications. Further, the vibration absorbing hinges are not limited to those equipped with a drive system such as an actuator, and may be mechanical hinges having a damper function.

[Effects of the Invention] As detailed above, according to the present invention, by arranging a hinge for vibration absorption in addition to a hinge for positioning,
It becomes possible to suppress vibrations generated in the arm, and it is possible to improve positioning performance.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram showing a manipulator according to an embodiment of the present invention, and FIG. 2 is a block diagram showing an example of a drive control system for a vibration-absorbing hinge in the manipulator.
FIG. 3 is a schematic configuration diagram showing a conventional manipulator. 1, ~, 6... Positioning hinge, 7, 8... Arm, 9... Hand, 10. ~,13...Vibration absorbing hinge, 21a, 21b displacement gauge, 22...Vibration detector, 23...Amplifier, 24...Actuator.

Claims (3)

[Claims] (1) In a manipulator that consists of multiple arms connected by hinges and that constitutes a spatial link mechanism as a whole,
In addition to a positioning hinge arranged to determine the spatial position and orientation of an arbitrary point of the arm, a vibration absorption hinge is arranged to absorb vibrations generated in the arm. manipulator. (2) The vibration absorbing hinge is rotatable in the same direction as the vibration direction generated in the arm, and is disposed on the proximal end side of the arm. The manipulator according to item 1. (3) The manipulator according to claim 2, wherein the vibration absorbing hinge is driven in accordance with a detection output of a vibration detector that detects vibrations of an arm on which the hinge is arranged.