JPH01164580A - Arm supporting structure of orthogonal type robot - Google Patents

Abstract

PURPOSE:To correctly control the shift and stop of a cantilever supporting arm by installing an arm supporting means having an electromagnet consisting of a superconductive coil which acts in the direction for offsetting the turning moment of the cantilever supporting arm around a supporting part by the action of the load. CONSTITUTION:An arm supporting means 19 is installed to offset the rightward moment which acts onto a supporting part 15 by a load W is installed at one edge part 12 of a cantilever supporting arm 10 in which the load acts onto the other edge part 14 side. The arm supporting means 19 is equipped with an electromagnet 20 consisting of a superconductive coil to attract one edge part 12 of the arm 10. Further, an arm supporting means 23 to offset the rightward moment which acts onto the supporting part 15 is installed onto the other edge part 14 of the arm 10. The arm supporting means 23 is equipped with an electromagnet 24 consisting of a superconductive coil to repel the other edge part 14 of the arm 10. Therefore, the shift.stop control in the X direction can be correctly carried out, generating the balance of the arm 10 by the actions of the means 19 and 23.

Description

[Detailed Description of the Invention] [Summary] Regarding a structure for supporting a cantilever support arm in order to counter the load acting on the cantilever support arm in an orthogonal robot, the present invention relates to a guide means for guiding and moving the cantilever support arm. The aim is to provide a small orthogonal robot that can reduce the acting load on the arm and accurately control the movement and stop of the cantilevered arm even during high-speed movement. In a cantilever support arm that is movably supported in one direction by a guide means and a load acts on the other end side, the rotational force of the cantilever support arm about the support part due to the action of the load. The arm support means is provided with an electromagnet made of a superconducting coil that acts in a direction to cancel the current.

[Industrial application field]

The present invention relates to a structure for supporting a cantilever arm in an orthogonal robot in order to counter loads acting on the cantilever arm.

[Conventional technology]

Cartesian robots have a simple configuration, so they are often used for automatic assembly. An example of its curved configuration is shown in FIG. The X-axis arm 30 is normally fixed to a base, and the Y-axis arm 32 is mounted in a direction perpendicular to the X-axis arm 30. This Y-axis arm 32 is controlled to stop moving in the X direction by a servo motor MX provided on the X-axis arm 30 via a ball screw shaft 28 and the like.

Further, a Z-axis arm 34 is attached to the Y-axis arm 32, and its movement in the Y direction is controlled by a servo motor MY attached to the Y-axis arm 32 via a ball screw shaft 38 and the like. This Z-axis arm 34 is equipped with a servo motor MZ.
is attached, and this servo motor MZ drives and controls the hand 36 that grips the object.

[Problem that the invention seeks to solve]

The orthogonal robot configured as described above has the following problems. First, in order to move the Y-axis arm 32 at high speed by the servo motor MX, it is necessary to reduce the weight of the Y-axis arm 32 and the Z-axis arm 34. However, since the Y-axis arm 32 has a cantilever structure with one end supported, it is difficult to make it thinner and lighter in order to maintain the rigidity of the robot. Further, the weight of the object load held by the hand 36 is not constant but fluctuates, and furthermore, the weight of the object load gripped by the hand 36 is
Since the shaft arm 34 moves in the Y direction, the load acting on the support portion of the Y-axis arm 32, ie, the threaded portion between the ball screw shaft 28 and the ball nut 40, changes. Therefore, Y
When controlling the high-speed movement of the shaft arm 32, vibrations in the X direction and the X direction are likely to occur, making accurate positioning control difficult.

On the other hand, if the orthogonal robot is configured in a gate shape, the Y-axis arm will have a double-supported beam structure and the rigidity will be high, but the problem is that the robot will be larger and the work direction will be limited due to the gate post getting in the way. There is.

Therefore, in order to solve these problems, the present invention reduces the load on the guide means for guiding and moving the cantilevered arm, and also precisely controls the movement and stop of the cantilevered arm even during high-speed movement. The purpose is to provide a small orthogonal robot that can

(Means for solving problems) FIG. 1 is a diagram explaining the principle of the present invention.

The cantilever support arm 10 has a support part 15 near one end 12 which is guided in the X direction by the guide means 10.
A load W is acting on the 4 side, and a clockwise moment is acting on the support portion 15.

On the other hand, arm support means 19 is provided at the one end 12 in order to cancel out the clockwise moment. This arm support means 19 includes an electromagnet 20 made of a superconducting coil to attract one end 12 of the arm 10. Further, instead of the arm support means 19 using this suction force, an arm support means 23 may be provided at the other end 14 of the arm 10 in order to cancel the above-mentioned clockwise moment. This arm support means 23 is the arm 10
An electromagnet 24 made of a superconducting coil is provided to repel the other end 14. Furthermore, the arm support means 19 and 23 may be used together.

[Function] According to the arm support means 19 and 23 described above, a counterclockwise moment acts on the support portion 15 of the arm 10, canceling out a clockwise moment caused by the load W. Therefore, the balance of the arm 10 is maintained, and it becomes easy to accurately control the movement and stop in the X direction.

Furthermore, when the arm support means 23 is used, the load W
The direction of the force and the direction of the repulsive force received from the superconducting coil electromagnet 24 are opposite to each other, and the total force acting on the arm 10 is also reduced, making it easier to control the movement of the arm 10.

[Embodiments] (a) Description of First Embodiment FIG. 2 is a perspective view of an orthogonal robot, which is a configuration diagram of a first embodiment of the present invention. A Y-axis arm 32 is mounted on the X-axis arm 30, which is fixed and extends in the horizontal X-direction relative to the base 42, and extends in the orthogonal horizontal X-direction.

The Y-axis arm 32 is controlled to stop moving in the X direction by a servo motor MX provided at the end of the X-axis arm 30 via the pole screw shaft 28 and the like. Further, a Z-axis arm 34 extending in the vertical direction Z is attached to the Y-axis arm 32, and a servo motor MY provided at the end of the Y-axis arm 32 moves the Z-axis arm 34 in the X direction via a pole screw shaft 38, etc. movement is controlled. A servo motor MZ is provided at the upper end of this Z-axis arm 34, and drives and controls a hand 36 provided at the lower end to grip the workpiece.

The Y-axis arm 32 has an end 32 on the side of the servo motor MY.
A pole nut 40 is attached near a and is screwed into the pole screw shaft 28. For this reason, the Y-axis arm 32 is a cantilever-supported arm, and not only is it subjected to the weight effects of the workpiece, the Z-axis arm 34, and the Y-axis arm 32 itself, but also the applied loads are applied to the Y-axis arm 32. support part,
That is, a large moment is generated with respect to the threaded portion between the pole screw shaft 28 and the pole nut 40.

In the present invention, a coil 44 made of superconducting material is embedded in the base 42 below the end 32a of the Y-axis arm 32 in order to reduce the excessive load on the drive devices 28, 40, and MX of the Y-axis arm 32 due to the above-mentioned moment. forms an electromagnet. This coil 44 is provided over the movement width of the Y-axis arm 32 in the X direction, and has an elongated loop shape.

Either the Y-axis arm 32 is made of a magnetic material, or a permanent magnet or an electromagnet 46 is fixed to the lower surface of the Y-axis arm 32 facing the superconducting coil 44, and the electromagnets 44 and 46 have different polarities. The Y-axis arm 32 is energized to attract the workpiece and the Z-axis arm 34.
A reverse moment acts to cancel the moment load due to the weight of the Y-axis arm 32 itself. Therefore, the Y-axis arm 32 is balanced, and vibrations are less likely to occur during high-speed movement stop control. The base 42 is preferably made of a magnetic material in order to reduce the magnetic resistance to the lines of magnetic force generated from the superconducting coil 44, and aluminum material (paramagnetic material) or the like is preferable in view of machining and cooling of the superconducting coil 44.

(b) Description of Second Embodiment FIG. 3 is a side view of an orthogonal robot, which is a configuration diagram of a second embodiment of the present invention, and FIG. 4 is a front view taken along the arrow line (■) in FIG. The second embodiment differs only in that an arm support means using a repulsive force is used on the other end 32b side of the Y-axis arm 32 instead of the arm support means using a suction force provided in the first embodiment. Therefore, a description of the common configuration will be omitted.

The end portion 32b, which is the free end of the Y-axis arm 32, is located in the X direction (
A column member 50 is fixed and extended in the vertical direction. A permanent magnet or electromagnet 52 is fixed to the lower end of this column member 50, and a coil 54 made of a superconducting material is embedded in the base 42 in the X direction so as to always face the magnet 52. This superconducting coil 54 is energized so that the magnetic poles facing the magnet 52 become the same polarity and repel each other. As a result, a reverse moment is applied to the Y-axis arm 32 to cancel out the moment due to the load. Furthermore, since the load in the X direction is also canceled out, the load acting on the Y-axis arm 32 is eliminated.

In practice, it is difficult to accurately cancel the moment and load caused by the load using only the arm support means having the configuration described above. Z along the longitudinal direction (X direction) of the Y-axis arm 32
In addition to the movement of the axis arm 34, the weight of the object held by the hand 36 is also not constant, so the amount of deflection of the Y-axis arm 32 varies. For this reason, the gap distance between the base 42 or the superconducting coil 54 and the magnet 52 is always measured by, for example, providing a capacitive type gap sensor 56 with respect to the magnet 52. The measurement signal of this sensor 56 is input to the gap calculation circuit 58 to calculate a gap value, and according to the gap value, the required repulsive force between the superconducting coil electromagnet 54 and the magnet 52 is calculated in the force conversion circuit 60. Based on this, the superconducting coil current control circuit 62 controls the current flowing to the superconducting coil 54. By using such a gap adjustment means, the Y-axis arm 3 can be adjusted by changing the movement of the Z-axis arm 34 or the gripping load of the hand 36.
It becomes possible to effectively cancel out the load on the Y-axis arm 32 and, by extension, the load on the mechanism that drives the Y-axis arm 32.

(Effects of the Invention) As is clear from the above description, according to the present invention, since a superconducting coil capable of passing a large current is used, it is possible to generate strong attractive force or repulsive force. It is an object of the present invention to provide a small orthogonal robot that can reduce the load on a guide support mechanism that supports and guides a cantilever support arm, and can accurately control the movement and stop of a cantilever support arm even during high-speed movement. It becomes possible.

[Brief explanation of the drawing]

Fig. 1 is a diagram explaining the principle of the present invention, Fig. 2 is a perspective view of the configuration of the first embodiment of the invention, Fig. 3 is a side view of the configuration of the second embodiment of the invention, and Fig. 4 is an arrow shown in Fig. 3. line of sight■
FIG. 5 is a front view and a perspective view of a conventional orthogonal robot. DESCRIPTION OF SYMBOLS 10... Cantilever support arm, 15... Support part, 19, 23... Arm support means, 20, 24
...Superconducting coil electromagnet, 22, 26... Opposing magnetic field generating means, 30... X-axis arm, 32... Y-axis arm, 34... Z-axis arm, 42... Base, 44. ...Superconducting coil, 46...Magnet, 52...Magnet, 54...Superconducting coil, 56...Gap sensor, W...Load.

Claims (3)

[Claims] 1. A support part (15) provided near one end (12) of the arm (10) is supported movably in one direction (X) by a guide means (16), and a load is applied to the other end (14) side. (W) acts in a direction that cancels out the rotational force of the cantilever support arm (10) about the support part (15) due to the action of the load (W). Electromagnet (20,
24) An arm support structure for an orthogonal robot, comprising arm support means (19, 23). 2. The arm support means (19) supports the arm (1).
0), the electromagnet (20) and the opposing magnetic field generating means (22) are provided at the one end (12) of the superconducting coil and facing the electromagnet (20) made of the superconducting coil. 2. An arm support structure for an orthogonal robot according to claim 1, wherein the arms are disposed with opposite poles facing each other. 3. The arm support means (23) supports the arm (
10), comprising an opposing magnetic field generating means (26) provided at the other end (14) and facing the electromagnet (24) made of the superconducting coil, the electromagnet (24) and the opposing magnetic field generating means (26) 2. An arm support structure for an orthogonal robot according to claim 1, wherein the arms are arranged opposite to each other with the same polarity.