JPH0683980B2 - Robot hand - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a robot hand suitable for handling cloth, paper, and other lightweight and delicately handled articles.

[Prior Art] Conventionally, a robot hand in which a plurality of finger pieces are connected at a joint is known. In such a hand, an ordinary motor (a motor driven by the interaction of current and magnetic field) is used to drive each joint individually.
It requires a brake to use gears to achieve low speed and high torque, and to fix the posture when stationary. Therefore, in addition to the self-weight of the motor, the weight of the fingertip side further increases, and accordingly, it is necessary to further increase the size of the fingertip on the base side and the motor for driving the fingertip, which significantly increases the overall size. Increase the weight. Moreover, when the above gear is used, backlash cannot be avoided, high-precision control is difficult, and rapid inertia change of the gear is difficult. The properties cannot be obtained, and therefore, it cannot be used at all for handling cloth, paper, and other articles requiring light and delicate handling.

Furthermore, in the case of using a wire to drive each joint with a motor provided on the base side, there is a difficulty in control that is inevitably caused by using the wire, and at the same time, the wire expands and contracts. There is also a problem that the precision of control is lowered.

[Problems to be Solved by the Invention] The technical problem to be solved by the present invention is to eliminate the need for a gear for driving a joint in a robot hand and a brake for maintaining a stationary state at low speed and high torque. , The number of components is reduced, the weight is reduced accordingly, the precision of control is improved, and the dynamic characteristics of the finger piece are improved by using a motor that has a large torque compared to its own weight. (EN) It is intended to obtain a robot hand adapted for handling paper and other light weight items that require delicate handling.

[Means for Solving the Problems] In order to solve the above problems, a robot hand of the present invention includes a plurality of fingers on a support member protruding from a base frame, and each finger is a support member protruding from the base frame. , The stator of the ultrasonic motor that constitutes the joint is attached, the finger piece is attached to the rotor of the ultrasonic motor, the stator of the ultrasonic motor that constitutes the next joint is attached to the finger piece, and the next It is constituted by attaching finger pieces and sequentially connecting a plurality of finger pieces by repeating this.

[Operation] Each of the fingers of the robot hand is given a necessary operation by controlling the ultrasonic motor that connects the finger pieces in the respective joints so that the fingers can be rotationally driven. In particular, it can be effectively applied to the handling of cloth, paper, and other articles that are lightweight and require delicate handling.

That is, since an ultrasonic motor that has a large torque compared to its own weight and volume is used, it is not necessary to drive each joint with gears for low speed and high torque or with a brake to maintain a stationary state. A robot suitable for handling the above-mentioned cloth, paper, etc. by reducing the number of constituent parts, achieving lightweight and downsizing, and achieving high-precision control, and improving the dynamic characteristics of the fingertips. It becomes possible to obtain a hand for use.

[Embodiment] FIGS. 1 to 3 show an embodiment of a robot hand according to the present invention.

The robot hand is used for handling cloth, paper, and other lightweight and delicate items that require delicate handling, and is particularly suitable for handling automatic sewing of cloth pieces.

In the illustrated robot hand, the base frame 1 is appropriately attached to the fixed portion 2, and the base frame 1 has three fingers 10, 20,
Equipped with 30. The index can be increased or decreased as needed.

The first finger 10 has a stator 16a of an ultrasonic motor 16 constituting a first joint attached to the tip of a supporting member 4 projecting laterally from the base frame 1 in FIG. By attaching the first finger piece 11 to 16b, the first finger piece 11 is attached so as to be rotatable about an axis parallel to the paper surface in FIG. Further, a stator 17a of a second ultrasonic motor 17 whose axis of rotation is orthogonal to the axis of rotation of the ultrasonic motor 16 is attached to the tip of the first finger piece 11, and a second finger is attached to its rotor 17b. The piece 12 is attached and the second ultrasonic motor 17 constitutes a second joint.

In the third joint, the stator 18a of the third ultrasonic motor 18 whose axis of rotation is parallel to the axis of rotation of the ultrasonic motor 17 is attached to the tip of the second finger piece 12, and the rotor 18b has a first joint 18a. Three
It is configured by attaching the finger piece 13 of, and the fourth joint is
A fourth axis whose rotation axis is also parallel to the tip of the third finger piece 13
Attach the stator 19a of the ultrasonic motor 19 of
It is configured by attaching the fourth finger piece 14 to 9b.

A fingertip piece 15 is attached to the tip of the fourth finger piece 14,
The shape and structure of the fingertip piece 15 is appropriately selected according to the target article handled by this hand.

The second finger 20 projects upward from the base frame 1 in FIG. 1, but as can be seen from FIGS. 2 and 3, the base portion of the second finger 20 has an arrow A in FIG. It is attached so that it can rotate in the direction indicated by. That is, the support member 5 attached to the base frame 1
The stator 26 of the ultrasonic motor 26 that constitutes the first joint.
a and attach the first finger to the rotor 26b of the ultrasonic motor.
21 is installed. The ultrasonic motor 26 has its axis of rotation oriented in a direction orthogonal to the plane of the drawing in FIG. 1. Therefore, the first finger 21 is driven by the ultrasonic motor 26 and is indicated by an arrow A in FIG. It will rotate in the direction. Further, at the tip of the first finger piece 21, there is provided a second ultrasonic motor whose axis of rotation is orthogonal to the axis of rotation of the ultrasonic motor 26.
27 stator 27a is attached to the rotor 27b and the second finger piece
22 is attached, and the second ultrasonic motor 27 constitutes a second joint.

In the third joint, a stator 28a of a third ultrasonic motor 28 whose axis of rotation is parallel to the axis of rotation of the ultrasonic motor 27 is attached to the tip of the second finger piece 22, and the rotor 28b is attached to the stator 28a. Three
It is configured by attaching the finger piece 23 of, and the fourth joint is
A fourth axis whose rotation axis is also parallel to the tip of the third finger piece 23
Install the stator 29a of the ultrasonic motor 29 of
It is configured by attaching the fourth finger piece 24 to 9b.

As with the first finger 10, a fingertip piece 25 having a necessary configuration is attached to the tip of the fourth finger piece 24.

The third finger 30 is projected upward from the base frame 1 in FIG. 1, and is attached to the tip of the support member 6 provided on the base frame 1 by the first finger 30.
The stator 36a of the ultrasonic motor 36 constituting the joint of FIG. 1 is attached, and the first finger piece 31 is attached to the rotor 36b of the ultrasonic motor. This ultrasonic motor 36 has the axis of rotation as the first axis.
In the figure, it is directed in a direction parallel to the paper surface. At the tip of the first finger piece 31, a second ultrasonic motor 37 whose axis of rotation is parallel to the axis of rotation of the ultrasonic motor 36 is provided.
Of the second finger 32 to the rotor 37b.
Is attached, and the second ultrasonic motor 37 constitutes a second joint. Furthermore, the third joint is the second joint described above.
Of the third ultrasonic motor 38 whose axis of rotation is parallel to the axis of rotation of the ultrasonic motor 37.
Is attached, and the third finger 33 is attached to the rotor 38b.

At the tip of the third finger piece, a fingertip piece 35 having the same necessary structure is attached.

The ultrasonic motor used for each joint of the finger is to generate a traveling wave that moves with time on a stator in which a piezoelectric ceramic is attached to an elastic body, and rotate a rotor that is in face-to-face contact with it through a lining. The drive can be controlled by the voltage applied to the motor.

The ultrasonic motor is driven by friction with the rotor via the lining, so if the friction coefficient of the friction part changes due to aging or temperature change, slip will change. By attaching a sensor such as an encoder or a potentiometer and performing feedback control, accurate position control corresponding to the resolution of the sensor can be performed. The stator of each ultrasonic motor described above has a support portion 41 provided on a part of a finger piece driven by the ultrasonic motor, or a support provided on a part of a stator of the ultrasonic motor attached to the finger piece. The parts 42 are made to face each other, and an encoder or the like can be attached between them.
When the sensor is mounted in this manner, it is integrated with the ultrasonic motor, so that the structure is made compact.

Each finger 10, 20, 30 of the robot hand having the above configuration,
The necessary operation is given by the control of the ultrasonic motor that rotatably drives the finger pieces at each joint, but in particular, because the ultrasonic motor is used to drive those joints, Making good use of characteristics, cloth,
It is possible to realize handling of paper and other articles that are lightweight and require delicate handling.

That is, since the ultrasonic motor has a large torque as compared with its own weight and volume, it does not require a gear for driving low speed and high torque or a brake for holding a stationary state to drive each joint, and the number of components is reduced. Therefore, it is possible to reduce the weight and size, and at the same time, it is possible to improve the accuracy of control. Also, since the ultrasonic motor itself is a simple and thin disk shape, even if it is attached to the joint,
The hand can be made sufficiently lightweight and compact. Further, in order to make the hand perform a complicated work, it is required to increase the number of joints as much as possible to increase the degree of freedom. As described above, the use of a lightweight and small motor achieves this. It will be possible.

Further, since the ultrasonic motor has a small rotor inertia force and a large torque, it has good controllability, and rapid rotation, stoppage, speed control, position control, etc. can be performed relatively easily. It is also excellent at low speed stability, which it is not good at. Therefore, as compared with the case of using an ordinary motor, it is possible to sufficiently improve the dynamic characteristics of the finger piece and obtain the robot hand suitable for handling the above-mentioned cloth, paper, and the like.

[Effects of the Invention] According to the robot hand of the present invention as described above, the following effects can be expected.

In the robot hand, unless the mechanism for rotating and driving each joint is made simple and lightweight, the base side is remarkably increased in size and weight for driving itself. However, when an ultrasonic motor having a very large torque as compared with its own weight and volume is used as in the present invention, it becomes possible to remarkably reduce the weight and downsize the whole, and to delicately handle cloth, paper, etc. It enables handling of required articles. Also,
Since the number of joints can be increased as the weight and size are reduced, more complicated and finer handling control can be realized.

In the robot hand, if the motor is equipped with a gear for low speed and high torque, the weight becomes heavier and the accuracy cannot be reduced due to backlash, but the ultrasonic motor used in the present invention is used. Has good stability at low speed, large torque can be obtained, and there is no need for gears for low speed and high torque.
The finger piece can be driven accurately and stably.

The robot hand often holds itself in a stationary state, but the ultrasonic motor has a maximum torque at rest when the power supply is cut off. Therefore, in the present invention, it is not necessary to provide a brake on each joint of the robot hand,
The weight can be reduced, and since energy is not required at rest, energy can be saved.

Robot hands that handle cloth, paper, etc. require excellent controllability, but ultrasonic motors
Compared to general motors, the torque is large and the rotor inertia is small, so the response is good, and since speed control and position control are easy, the controllability is sufficiently enhanced and excellent dynamic characteristics are obtained. You can

Since the ultrasonic motor is used, it is not affected by electromagnetic noise and does not affect other devices.

[Brief description of drawings]

The drawings show an embodiment of a robot hand according to the present invention. FIG. 1 is a front view thereof, FIG. 2 is a side view thereof, and FIG. 3 is a plan view thereof. 10,20,30 …… Finger, 11〜14,21〜24,31〜33 …… Finger piece, 16〜19,26〜29,36〜38 …… Ultrasonic motor.

Claims (1)

[Claims] 1. A support member protruding from a base frame is provided with a plurality of fingers, and each finger has a stator of an ultrasonic motor constituting a joint attached to the support member protruding from the base frame, and the fingers of the ultrasonic motor are Attach the finger piece to the rotor, and then attach the stator of the ultrasonic motor that constitutes the next joint to the finger piece,
A robot hand in which a plurality of finger pieces are sequentially connected by attaching the next finger piece to the rotor and repeating this.