JPH01210283A - Industrial robot - Google Patents

Abstract

PURPOSE:To enable a movable part of an industrial robot to be stopped easily by installing a power generation braking circuit for interposing, between coils of an electric motor, a resistance for consuming the generated power of the electric motor following the movement of the movable part during a process of instruction. CONSTITUTION:When the output shaft of an electric motor 4 is rotated by using a permanet magnet to provide a field system, in order to move the movable part (arm) of a robot, electromotive power is generated between coils of the electric motor. Then, a power generation braking circuit (direct brake circuit) 5 is put on by a switch means 6, a resistance is interposed between these coils so as to consume the electromotive power generated by this process of interposition for braking the output shaft of the electric motor 4 by consumption of rotational movement energy, thus the movable part of the robot is stopped. On the other hand, the output shaft of the electric motor 4 can rotate smoothly because no consumption by a resistance may take place by putting this braking circuit 5 in off state.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an industrial robot whose movable parts are driven by an electric motor (for example, a synchronous machine).

[Prior Art] In recent years, robots employing a direct teaching method have been mainly used in various industries including industry.

This direct teaching robot is one in which a human moves the robot's movable parts (for example, an arm) to change the motion (
The robot stores teaching points (teaching points) and operates along the teaching points during playback, such as painting robots and welding robots.

Here, FIG. 5 shows the state of direct teaching of the painting robot 2, and as shown in this figure, the teacher l holds the tip of the arm 2a and teaches the painting operation to the workpiece 3. . In this case, each time the tip of the arm 2a is brought to a teaching point, a teaching switch (not shown) is turned on, and the teaching point at that time is stored in the memory section (indicated path) in the robot 2.
is stored in the memory.

[Problems to be Solved by the Invention] In the above-mentioned direct teaching type robot, in order to reduce the operating force required to move the arm during teaching, the output shaft of the reducer attached to the output shaft of the electric motor and the robot A clutch is provided between the axis of the joint (hereinafter referred to as the joint axis) (this type of system has been adopted in a painting robot already developed by the applicant).

In addition, if the reduction gear and clutch are omitted,
There is also a direct drive system in which the robot's joint axes are directly connected to the output shaft using an electric motor with low resistance during rotation3.By the way, with the direct drive system mentioned above, it is possible to reduce the operating force. On the other hand, since the resistance during rotation is small, when the arm's own weight increases and the inertial load increases, the arm cannot be easily stopped, making teaching difficult.

This invention was made in view of two consecutive circumstances, and provides an industrial robot that can easily stop the robot arm even when its own weight increases and the inertial load increases. This is the main objective.

[Means for Solving the Problems] In order to achieve the object stated in item 1, according to the present invention, in a direct teaching type industrial robot in which the movable part is moved by an electric motor, the movable part is A dynamic braking circuit in which a resistor is inserted between the windings of the motor to consume power generated by the motor as the motor moves, and a shift switch means for controlling on/off of the dynamic braking circuit. shall be.

[For Use] According to the present invention, for example, by rotating the output shaft of a motor using a permanent magnet as a field, an electromotive force is generated between the armature windings.

At this time, by inserting a resistor between the armature windings,
], the generated electromotive force is consumed, the energy of the rotational movement is consumed, and the output shaft of the motor is braked.

On the other hand, by opening the armature windings, there is no consumption due to resistance, so the output shaft of the motor rotates smoothly.

[Example] Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing the electrical configuration of an embodiment of the present invention.
This is applied to the painting process shown in the figure.
In this figure, 4 is an electric motor (hereinafter referred to as motor) that uses a permanent magnet for the field, and its output shaft is connected to arm 2.
It is connected to the joint shaft of a (see Fig. 5). 5 is a dynamic brake circuit, and its output terminal Bo+~BO
3 and the U, V, and W phases of the armature winding of the motor 4 are connected, respectively.

This dynamic brake circuit 5 performs dynamic braking of the motor 4 according to the open/close state of a switch 6 attached to the tip of the arm 2a.

Here, FIG. 2 is a wiring diagram showing the electrical configuration of the dynamic brake circuit 5. As shown in FIG. In this figure, 8 is a relay circuit, with relay contacts 8a to 8e and a coil 8.
It is composed of f. Relay contacts 8a, 8c and 8e connect input ends Bl,~B13 and output end BO1-
130, respectively.

Also, the output horn end B0 is connected via the relay contact 8b or the resistor 9a.
1 and BO2, and the relay contact 8 (] is connected to the resistor 9
It is inserted between the output ends Bo and BO3 via the terminal B. Further, the relay contacts 8a, 8c, and 8e are normally closed, and the relay contacts 8b, 8c, and 8e are normally closed.
8d is in a normally open state (normally open).

Further, these relay contacts 8a to 8e are arranged to work together. Relay coil 8f is connected to power supply IO via switch 6.

” Input terminal Bi+ of the double dynamic brake circuit 5
-Bi is connected to the output terminal Dot-DO3 of the drive circuit 7. The drive circuit 7 drives the motor 4, and is supplied with power from a power supply section (not shown).

Next, the operation of the structure shown in "-" will be explained. Note that during teaching, no voltage is applied from the drive circuit 7 to the dynamic brake circuit 7.

Now, the teacher 1 holds the tip of the arm 2a and positions the tip of the arm 2a at the first teaching point with respect to the workpiece 3. At this time, when the teacher 1 brings the tip of the arm 2a slightly in front of the desired first teaching point, the switch 6
is closed. As a result, relay contacts 8a, 8c, and 8e in dynamic brake circuit 5 are each in an open state, and relay contacts 8b, 8d are each in a closed state.

As a result, resistors 9 a and 9 b are inserted between the U phase and the ■ phase and the V phase and the W phase of the armature winding of the motor 4, respectively. As a result, the electromotive force generated between the armature windings of the motor 4 is consumed by the resistors 9a and 9b, and the motor 4 is braked to stop the arm 2a.

After the arm 2a has stopped, the teacher I turns on a teaching switch (not shown) to store the first teaching point in the storage section (path shown) of the robot 2.

Next, after storing the first teaching point, the teacher 1 opens the switch 6 in order to store the next teaching point.

As a result, relay contacts 8a, 8c, and 8e in dynamic brake circuit 5 are each in a closed state, and relay contacts 8b, 8d are each in an open state. As a result, the resistors 9-=7a, 9b are opened between the U phase, V phase, and W phase of the armature winding of the motor 4. As a result, the electromotive force generated between each armature winding of the motor 4 is transferred to the resistors 9a and 9b.
The output shaft of the motor 4 rotates smoothly. Therefore, the instructor l can easily move the arm 2a, and the desired second
The arm 2a is moved close to the teaching point A. Then, when the arm 2a is brought slightly before the desired second teaching point, the switch 6 is closed in the same manner as described above, and the braking force is applied to the motor 4 to stop the arm 2a.

Next, after stopping the arm 2a, the teaching switch is turned on to store the second teaching point in the storage section.

Hereafter, the desired 3rd. When the tip of the arm 2a is positioned at the fourth teaching point, the above-mentioned operation is performed to store the teaching point in the storage section. After all the teaching points are stored, by turning on a playback switch (not shown), the control section operates according to the instructed teaching points based on the teaching data stored in the storage section.

Next, another application example of the above-mentioned dynamic brake circuit 5 will be explained.

FIG. 3 is a wiring diagram showing the electrical configuration of the first application example of the dynamic brake circuit 5. In FIG. In this diagram,
11 is an electric variable resistor, variable resistors 11a, Il
b and a coil Ilc, and a variable resistor 11a, which is proportional to the voltage application time to the coil Ilc.
Each resistance value of Ilb is designed to decrease. These variable resistors 11a and llb are interposed between the resistor 9a and the relay contact 8b and between the resistor 9b and the relay contact 8d, and the coil llc is connected to a power source 10 via a switch 12. In this way, by connecting the variable resistors 11a and llb to the resistors 9a and 9b, when the switch 6 is closed, the value of the resistor inserted between each phase of the motor 4 can be changed, and the motor The braking force of 4 can be set arbitrarily. Therefore, it is possible to arbitrarily set the time from when the switch 6 is closed to when the arm 2a completely stops.

Next, FIG. 4 shows the second part of the dynamic brake circuit 5.
FIG. 2 is a wiring diagram showing an electrical configuration of an application example of the present invention. In this application example, instead of the electric variable resistor used in the first application example above, several weighted resistances are combined to change the braking force in stages, as shown in the figure. This is a simple structure.

In FIG. 4, a relay circuit I3 is composed of normally closed relay contacts 13a to 13c and a relay coil 13d. These relay contacts 13a-13c are an output end Bo+-BO3 and an input end Bi.

It is inserted between ~BL. 14 to 16 are relay circuits, respectively, including relay contacts 14a, 14b and a relay coil 14c, relay contacts 15a, 15a and a relay coil 15c, and a relay contact 16a.

16a and a relay coil 16c.

These relay contacts 14a to +6a and 14b to 16b
is always open. Further, relay contacts 14a and +4b, +5a and 15b, and 16a and +6b are interlocked, respectively.

17a to 17f are resistors, and among these, resistor 1
One end of each of 7a to 17c is connected in common and connected to the output end Bot, and the other end is connected to relay contacts 14a, 15a and 1.
6a. In addition, the resistance 17d~1
The resistors 17a to 17c mentioned above have one end of each of the resistors 17a to 17c commonly connected to the output end BO2, and the other ends of each of the resistors 17f and 7f are connected to one end of each of the relay contacts +4b, +5b and +6b.
are each weighted (-1+:l, 17a, I
The resistance value decreases in the order of 7b and 7c.

Also, resistors +7a and 17d, resistors 171) and 17e and j
; and resistors 17c and 17f are each set to the same value. Said relay contact 14. The other ends of relay contacts +4.11, +5a and 16a are commonly connected and connected to output end BO2, and the other ends of relay contacts +4.11, 1511 and 16b are commonly connected and connected to output end Bo3. Relay coil +
4c, 15c and 16c are commonly connected and connected to one end of relay coil l3 (1, relay coil 1
4. The other ends of c, 15c and 16c are connected to switches 18-
20. And switch 18~
The other ends of the coils 20 are commonly connected and connected to the other end of the relay coil 13d via the power source IO.

With this configuration, as the rotational speed of the motor 4 decreases, the switches 18 → 19 → 20 are closed step by step in the order of the motor 4 to reduce the value of the resistance inserted between the armature windings of the motor 4. This has the advantage that the optimum braking effect can always be obtained.

In addition, in the embodiment mentioned above, the motor 4 in which a permanent magnet was used for the field and a winding was used for the armature was used;
A motor in which a winding is used for the field and a permanent magnet is used for the armature may be used. Furthermore, the motor may be for direct current or alternating current.

[Effects of the Invention] As explained above, according to the present invention, in a direct teaching type industrial robot in which the movable part is moved by an electric motor, ()fi is applied to the direct teaching ILlj.
a dynamic braking circuit in which a resistor is inserted between the windings of the motor to consume power generated by the motor as the recording moving part moves;
A switch means for controlling on/off of the dynamic braking circuit is provided. By turning it on and inserting the resistor into the electric motor, the movable part can be easily stopped.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the electrical configuration of an embodiment of the present invention, FIG. 2 is a wiring diagram showing the electrical configuration of the main parts of the embodiment, and FIG. Fig. 4 is a wiring diagram showing the electrical configuration of the second application example of the same main part, and Fig. 5 is a wiring diagram showing the electrical configuration of the second application example of the same main part. It is a diagram showing the state of teaching. 4. Electric motor, 5. Guinami Sokburegi circuit (dynamic braking circuit),
6.12.18, 19.20 Switch (switch means).

Claims (1)

[Claims] In a direct teaching type industrial robot in which a movable part is moved by an electric motor, dynamic braking is provided in which a resistor is inserted between the windings of the motor to consume power generated by the motor as the movable part moves during direct teaching. An industrial robot comprising: a circuit; and a switch means for controlling on/off of the dynamic braking circuit.