JPH0461225B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a single-point-centered three-degree-of-freedom joint mechanism used for the shoulder joint of a prosthetic hand, the hip joint of a prosthetic leg, and the joints of robots that require similar movements.

Human shoulder joints and hip joints are parts that have three degrees of freedom of movement centered on one point, like ball joints, and artificial joints used in such areas also have three degrees of freedom of movement centered on one point using actuators. It is desirable to have a degree of movement. however,
It is difficult to construct a drive mechanism with three degrees of freedom similar to a ball joint, so in the past, in order to approximate this, three one-degree-of-freedom drive mechanisms were installed in series, or two-degree-of-freedom drive mechanisms were installed. A one-degree-of-freedom drive mechanism was attached to the 1-degree-of-freedom drive mechanism, but these were not so-called single-point-centered types in which the three rotating axes intersect at one point, and therefore neither of them could provide the same movement as a ball joint. Moreover, there is a problem in that the algorithm for controlling the movement becomes complicated.

Furthermore, even if such a one-point-centered three-degree-of-freedom rotation mechanism could be realized, it would be desirable to exhibit a self-locking function, especially when it is used in joints of robots and the like. In other words, in robots, it is usually possible to drive a driven body by an actuator, but the load acting on the driven body is not transmitted to the actuator, and the joints are locked. It is desirable that the With this configuration, it is possible to resist the load without supplying power to the actuator, and it is only necessary to supply power to the actuator when driving the joint.

In view of the above, the present invention aims to provide a joint mechanism of a simple structure that can perform movement in three degrees of freedom centered on one point like a ball joint, and at the same time has a self-locking function. It is something.

To achieve the above object, the 3-degree-of-freedom joint mechanism of the present invention has a first frame rotatably supported by a first shaft on a main body to which the 3-degree-of-freedom joint mechanism is attached, and a first frame body is rotatably supported on the main body. a first one-degree-of-freedom drive mechanism in which a worm rotatably driven by a provided first actuator is engaged with a worm wheel integrated with a first frame; A second frame body is rotatably supported by a second axis orthogonal to the axis, and a worm rotatably driven by a second actuator provided on the first frame body is integrated with the second frame body. a second one-degree-of-freedom drive mechanism meshed with the worm wheel;
a third actuator provided on the second frame body, the third actuator having a third axis orthogonal to the first and second axes at one point with respect to the frame body and rotatably supporting the driven body; A third one-degree-of-freedom drive mechanism is provided in which a worm rotatably driven by a worm wheel meshes with a worm wheel integrated with a driven body.

According to the three-degree-of-freedom drive mechanism having such a configuration, by coupling the first to third one-degree-of-freedom drive mechanisms, it is possible to perform movement in three degrees of freedom around one point, similar to a ball joint. At the same time, a simple joint mechanism having a self-locking mechanism can be obtained.

Embodiments of the present invention will be described in detail below with reference to the drawings.

The three-degree-of-freedom joint mechanism shown in FIG.
has three degrees of freedom around the center O, that is, a body A to which this three-degree-of-freedom joint mechanism is attached is three-dimensionally orthogonal to the main body A with the center O as the intersection.
The driven body 1 is configured to be able to rotate around the axes, y-axes, and z-axes.

The rotation of the driven body 1 around the x-axis is a first freedom that rotates the first frame 2 around the x-axis with respect to the main body A of a robot or the like, which is the attachment part of the three-degree-of-freedom joint mechanism. This is done by a degree drive mechanism. Therefore, a worm wheel is provided in which a first shaft 3 is rotatably supported on the main body A, and a worm 5 is fixed to the first shaft 3, and the worm 5 is rotatably driven by a first actuator 4 provided on the main body A. 6, and the first frame 2 is fixed on the shaft 3.

Therefore, when the first actuator 4 on the main body A rotates the first shaft 3 via the worm 5 and the worm wheel 6, the driven body 1 on the main body A rotates x along with the first frame 2, etc. Rotated around an axis.

The second one-degree-of-freedom drive mechanism provided on the first frame 2 is rotatably supported on the first frame 2, and its central axis is aligned with the axis of the first shaft 3 (x-axis ), and a second frame 12 rotatably supported by the first frame 2 by being fixed to the second axis 13. , the second frame 12 by being fixed to the second shaft 13
The worm wheel 16 is fixed to and rotatably supported by the first frame 2 together with the second frame 12 thereof. In addition, this second frame 12
In order to rotationally drive the worm wheel 16 around the y-axis, a worm 15 that is rotatably driven by a second actuator 14 provided on the first frame 2 is meshed with the worm wheel 16.

Therefore, when the second actuator 14 provided on the first frame 2 rotates the worm wheel 16 via the worm 15, the second actuator 14 rotates the worm wheel 16 accordingly.
The frame body 12 is rotated together with the driven body 1 around the y-axis within a certain angular range.

The third one-degree-of-freedom drive mechanism provided on the second frame 12 is rotatably supported on the second frame 12 and has its central axis aligned with the first and second shafts 3,
13 and a worm wheel 26 fixed on the third shaft 23, and connects the driven body 1 to the third shaft 23. That's what I do. Further, in order to rotationally drive the third shaft 23, a worm 25, which is rotationally driven by a third actuator 24 provided on the second frame 12, is engaged with a worm wheel 26 on the third shaft 23. There is.

Therefore, when the worm wheel 26 is driven via the worm 25 by the third actuator 24 provided on the second frame 12, the driven body 1 is rotated around the z-axis accordingly.

When the three-degree-of-freedom joint mechanism having the above configuration is used, for example, as a shoulder joint of a robot, the main body A is configured as a robot main body, and the first shaft 3 is rotatably supported by the robot main body, and
It is sufficient to attach the arm of the robot as the driven body 1, and in this state, the three actuators 4, 14,
By appropriately controlling the rotational direction and rotational speed of the worm wheels 6, 16, 26 by the control device, the actuators 4, 14, 2
4, the first and second frames 2, 12 and the driven body 1 rotate around the x, y, and z axes, and the robot arm rotates 3 around the center O with respect to the robot body A. It will rotate with degrees of freedom.

In the three-degree-of-freedom joint mechanism, in each of the first to third one-degree-of-freedom drive mechanisms, the worms 5, 15, 25 to the worm wheels 6, 16 are rotationally driven by the actuators 4, 14, 24. , 26, the first and second frames 2, 12 and the driven body 1 are driven by the actuator.
Although it is possible to drive the driven object 1
The load acting on the actuator is not transmitted to the actuator, and the joint is maintained in a locked state. Therefore, it is possible to resist the load without supplying power to the actuator, and by supplying power to the actuators 4, 14, and 24 only when driving the joint, and in addition, a three-degree-of-freedom device with such a self-locking mechanism can be used. A joint mechanism can be obtained with a simple configuration.

As described above, according to the present invention, it is possible to make a driven body rotate around three three-dimensionally perpendicular axes at one point, and at the same time, a three-degree-of-freedom joint mechanism with a self-locking function can be constructed with a simple configuration. Since the algorithm for controlling the movement is simple, it can be used extremely effectively for artificial joints, etc.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of an embodiment of the invention. 1... Driven body, 2, 12... First and second frame bodies,
3, 13, 23...first, second, third axis, 4,1
4, 24... actuator, 5, 15, 25... worm, 6, 16, 26... worm wheel.

Claims (1)

[Claims] 1. A main body to which a three-degree-of-freedom joint mechanism is attached,
A first frame body is rotatably supported by a first shaft, and a worm that is rotationally driven by a first actuator provided on the main body is engaged with a worm wheel integral with the first frame body. a 1-degree-of-freedom drive mechanism; and a second frame is rotatably supported by a second axis orthogonal to the first axis with respect to the first frame;
A second worm wheel is provided in which a worm rotatably driven by a second actuator provided on the first frame is engaged with a worm wheel integral with the second frame.
a degree-of-freedom drive mechanism; and a third shaft that is perpendicular to the first and second axes at one point with respect to the second frame and rotatably supports the driven body, the second frame A third one-degree-of-freedom drive mechanism in which a worm rotatably driven by a third actuator provided on the body is meshed with a worm wheel integrated with the driven body. Single-point centered 3-degree-of-freedom joint mechanism.