JPH0341705B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a three-axis drive unit used in joints of robot arms, etc.

[Prior Art] The present inventors previously proposed a three-dimensional motor having three degrees of freedom as one of this type of drive units (Japanese Patent Application No. 59-60058).

The above-mentioned three-dimensional motor has windings that generate rotating magnetic fields around axes in three directions that are orthogonal to each other, and a stator that can generate a composite rotating magnetic field in any direction. It is constructed by providing a rotor that is rotatably supported.

However, since this three-dimensional motor is configured as a synchronous motor or an induction motor, its structure and control system are complicated, and since it is a direct drive type, it is difficult to drive at high torque. have.

[Problems to be Solved by the Invention] An object of the present invention is to provide a three-axis drive unit that is simple in structure and control, capable of high-torque drive, and capable of accurate positioning control.

[Means for Solving the Problems] In order to achieve the above object, the three-axis drive unit of the present invention has an outer spherical shell attached to the shaft rod on the fixed side.
The inner spherical shell attached to the shaft rod on the driven side is housed so as to be relatively rotatable, and the outer spherical shell and the inner spherical shell are connected via a gimbal mechanism that is rotatable around three orthogonal axes. At the same time, three rotary actuators are installed on the outer spherical shell side to decelerate and rotate the inner spherical shell around the three axes via friction wheels, and the rotation angles of the rotating parts around the three axes in the gimbal mechanism are adjusted. and rotation measuring means for detecting the rotational angular velocity and feeding it back to the input side of the actuator.

[Operation] In the three-axis drive unit of the present invention having the above configuration, when each actuator is driven, the inner spherical shell undergoes synthetic rotation around the X-axis, Y-axis, and Z-axis according to the driving force components of these actuators. and can be driven in any direction. Therefore, the shaft rod on the driven side attached to the inner spherical shell can also be driven and displaced to an arbitrary position together with the inner spherical shell.

The rotational angle and rotational angular velocity of the inner spherical shell are detected by the rotation measuring means, and are fed back to the control device on the input side of the actuator, whereby the inner spherical shell, that is, the shaft rod on the driven side, is accurately positioned at an arbitrary position. is positioned.

Further, the torque of the actuator is amplified by the reduced rotation of the inner spherical shell by the friction wheel, thereby achieving high torque drive.

[Effects of the Invention] According to the present invention having the above configuration, an existing rotary actuator can be used.
Its structure is extremely simple and compact, and since the inner spherical shell is decelerated and rotated via a friction wheel, it is possible to drive with high torque. By measuring the rotation angle and rotation angular velocity of the rod around the three axes, accurate positioning control can be performed.

[Example] Hereinafter, an example of the present invention will be described in detail based on the drawings.
The shaft drive unit accommodates an inner spherical shell 5 attached to a shaft rod 2 on the driven side in an outer spherical shell 4 attached to a fixed side shaft rod 1 of a robot arm or the like so as to be relatively rotatable therein. The shell 4 and the inner spherical shell 5 are connected via a gimbal mechanism 6 that enables rotation around three axes perpendicular to each other, that is, the X axis, the Y axis, and the Z axis, and both the spherical shells 4 and 5 are provided with openings 7 and 8 to enable relative displacement with the shaft rods attached to the opposing spherical shells.

The gimbal mechanism 6 has substantially arc-shaped support arms 11 and 12 rotatably attached to arms 9 and 10 that are integrated perpendicularly to the X-axis direction and the Y-axis direction, and one of the support arms 11 , the shaft rod 2 on the driven side is mounted so as to be rotatable around the Z-axis, with the shaft rod 2 on the driven side facing the Z-axis direction, and the other supporting arm 1
2, the fixed side shaft rod 1 is fixedly attached.

On the outer spherical shell 4 side, as shown in FIG. Rotary actuator 14 consisting of etc.
16 and the friction wheel 17 attached to the rotating shaft of each actuator is inserted into the hole 18 provided in the outer spherical shell 4.
It is brought into contact with the inner spherical shell 5 through the inner spherical shell 5.

In addition, in order to control the positioning of the inner spherical shell 5, that is, the shaft rod 2 on the driven side, to an arbitrary position, the rotation part around the three axes in the Zirval mechanism 6 is equipped with an angle sensor that detects the rotation angle of each axis. Rotation measuring means 19 to 21 each consisting of a rotation measuring device 22 and an angular velocity detector 23 for detecting each rotation speed are provided, and measurement signals from each rotation measuring means are transmitted to the actuators 14 to 16.
It is configured to feed back to the input side of the controller, that is, to a control device (not shown).

The rotation measuring means 19 to 21 can be configured by, for example, a potentiometer, a resolver, or the like.

In the 3-axis drive unit having the above configuration,
When each actuator 14 to 16 on the outer spherical shell 4 is driven, the inner spherical shell 5 rotates synthetically around the X-axis, Y-axis, and Z-axis according to the driving force components of these actuators, and rotates in any direction. Driven. Therefore,
The shaft rod 2 on the driven side attached to the inner spherical shell 5 is also driven to an arbitrary position together with the inner spherical shell 5.

The rotational angle and rotational angular velocity around the three axes of the inner spherical shell 5, that is, the driven shaft rod 2, are detected by rotation measuring means 19 to 21 built into the gimbal mechanism 6, and are used to control each actuator 14 to 16. Feedback is provided to the device, whereby the driven shaft rod 2 can be accurately positioned at any desired position.

Further, due to the decelerated rotation of the inner spherical shell 5 by the friction wheel 17, the torque of each actuator 14 to 16 is amplified and transmitted to the inner spherical shell 5, thereby performing high torque driving.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway perspective view schematically showing an embodiment of the present invention, and FIG. 2 is a side view showing how the actuator is attached. 1... Fixed side shaft lever, 2... Driven side shaft lever, 4...
...Outer spherical shell, 5...Inner spherical shell, 6...Gimbal mechanism,
14, 15, 16... Actuator, 17...
Friction wheels, 19, 20, 21... Rotation measuring means.

Claims (1)

[Claims] 1. An inner spherical shell attached to a shaft rod on the driven side is accommodated in an outer spherical shell attached to a fixed side shaft rod so as to be relatively rotatable, and these outer spherical shells and inner spherical shells are arranged perpendicularly to each other. Three rotary actuators are attached to the outer spherical shell side through a gimbal mechanism that is rotatable around the axes and rotate the inner spherical shell at a reduced speed around the three axes through friction wheels. A three-axis drive unit characterized in that rotation measuring means for detecting rotation angles and rotation angular velocities of rotation parts around three axes of a gimbal mechanism and feeding them back to the input side of an actuator is provided.