JPH0211394B2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a control device for an industrial robot, and is capable of testing the brake torque of a brake that mechanically brakes a movable body such as the vertical axis or arm of a robot in an emergency. This is how it was done.

Generally, this type of industrial robot is provided with a mechanical brake that brakes its vertical axis or movable body such as an arm. This brake is used not only to hold the movable body in a stopped position, but also to stop the movable body in the event of an emergency.

By the way, conventionally it has not been possible to determine whether or not the above-mentioned brake has the necessary brake torque for stopping in an emergency. Therefore, if this torque is insufficient, even if it is necessary to stop the movement of the movable body due to an accident with the peripheral equipment of the robot, the movable body will not be stopped in a short time (within a predetermined distance); This had the disadvantage of damaging the movable body or peripheral equipment.

The present invention aims to eliminate the above-mentioned conventional drawbacks and to provide a control device for an industrial robot that can test whether or not the brake torque is sufficient when automatically operating the industrial robot. This is the purpose.

FIG. 1 is a so-called claim correspondence diagram showing the configuration of the present invention, and the configuration will be explained with reference to this diagram. An industrial robot 100 has a movable body 101 such as a vertical axis or an arm, and the movable body 101 is connected to a motor 102.
and is mechanically braked by the brake 103. As the movable body 101 moves, a voltage proportional to the speed of the movement is generated by a voltage generator 104 such as a tachogene. Movable body 1
01 comes to a predetermined position by its movement, the first switch 105 is operated, and the moving speed of the above-mentioned movable body 101 at the time when the switch 105 is operated is taken into the detection means 106. It is compared with the rated speed set in the setting device 107, and if the moving speed is equal to or higher than the rated speed,
A command is issued by the control means 108 to cut off the power supply to the motor 102 and to operate the brake 103. This command causes the movable body 101, which had been moving at the rated speed (or a speed exceeding this), to be braked, and the movable body 101 is stopped in a short time. When the movable body 101 is moved from the position where the first switch 105 is operated by a distance corresponding to the maximum stopping distance due to brake operation at the set brake torque, the movable body 101 is moved from the position where the first switch 105 is operated. There is a second switch 109 operated by the movable body 101, and the first switch 105 is operated by the movable body 101.
is operated, and if the second switch 109 is not operated before the movable body 101 is braked and stopped, a signal is sent to the operation control system 110 to enable automatic operation of the robot, and the second switch 109 is activated.
9 is operated, a display to that effect is displayed and the torque of the brake 103 can be readjusted.

Next, to explain one embodiment of this invention, the second
The figure shows the configuration of an industrial robot, where 1 is the main body of the robot, which includes a vertical shaft 2, a first arm 3 connected to the vertical shaft, and a second arm connected to the first arm. It is composed of 4 etc. 5 is vertical axis 2
The motor 5a that drives the motor is a voltage generator (tachogenerator) that generates a voltage proportional to the rotation of the motor. A mechanical brake 6 is attached to the shaft of this motor 5.
and gear 7 are coupled, and the torque of motor 5 is transmitted to ball screw 10 via gears 7, 8, 9,
The vertical shaft 2 is configured to be moved by rotation of the ball screw. Due to the rotational direction of the motor 5, the upper shaft 2 moves along the linear way.
Upper and lower limit switch 11a and lower limit switch 11
moved upward or downward between b and b. 12 is a motor that drives the first arm 3, and 12a is a voltage generator that generates a voltage proportional to the number of rotations of the motor. A mechanical brake 1 is attached to the shaft of this motor 12.
3 are connected to each other, and the rotational force of the motor 12 is transmitted to the first arm 3 via a gear (not shown). With this configuration, the first arm 3 is rotated to the left or right between the left limit switch 21 and the right limit switch 22 shown in FIG. 3, depending on the direction of rotation of the motor 12. Similarly to the first arm 3, the second arm 4 is connected to a motor, a voltage generator, a mechanical brake, gears, etc. (not shown), and is connected between a left limit switch and a right limit switch (not shown). It is configured so that it can be rotated to the left or right.

The motors 5, 12, etc. described above are controlled by a control panel 18 via a cable 17 connected to the main body 1 of the robot.

The structure and operation of this control panel 18 will be explained with reference to FIGS. 4 and 5. This explanation is about the vertical axis 2, but since the operations of the first arm 3 and the second arm 4 are substantially the same, the explanation of the operations of the first arm 3 and the second arm 4 will be omitted. 31 is
For example, when the CPU issues a command to ascend the vertical axis 2, this command signal is sent to the amplifier 3.
2, a power supply current is supplied to the motor 5 via a contact A1, which will be described later, and the rotation of the motor 5 causes the vertical shaft 2 to run (move) upward. The traveling speed of the vertical shaft 2 has a waveform as shown in FIG. That is, if the starting point is l ₁ and the target point is l ₄ , then
It is controlled so that it starts accelerating at the l ₁ position, reaches the rated speed at the l ₂ position, starts decelerating at the l ₃ position, and stops at the l ₄ position.

When you want to suddenly stop the vertical axis 2, the CPU
31 or by pressing the emergency stop button 37, the relay 36 is dropped out via the relay drive circuit 35, and its make contacts A1 and A2 are opened. By opening the contact A1, the power supply current to the motor 5 is cut off, and by opening the contact A2, the power supply current to the solenoid that was releasing the braking by the mechanical brake 6 is cut off. As a result, the vertical shaft 2 is mechanically braked by the brake 6 without being driven by the motor 5, and is stopped at a distance _l5 to _l6 shorter than the normal deceleration distance _l3 to _l4 described above. .

By the way, if the torque of the mechanical brake 6 is less than the torque that overcomes the inertia and weight of the vertical shaft 2, it will not be possible to stop within a short distance as described above, and the vertical shaft 2 or peripheral equipment may be damaged. There was a risk that it would happen. This is not limited to the vertical axis 2, but the same can be said of the first arm 3 and the second arm 4.

For this reason, it is necessary to always set the brake torque force of the mechanical brakes 6, 13, etc. above the specified value, but in the device shown in Fig. 3, the brake torque force is set as shown in Fig. 6. It is configured so that it can be checked that the value is above a specified value. The brake 6 will be mainly explained using the flowchart shown in FIG. First, when the mechanical brake torque test mode is selected by the CPU 31, the vertical shaft 2 moves downward, and this movement causes the voltage generator 5a to obtain a voltage proportional to the moving speed. When the vertical shaft 2 is moved to a predetermined position, the first switch (X) 15 is operated, and this operation is notified via the interface 33.
The voltage from the voltage generator 5a, which is transmitted to the CPU 31 and is proportional to the moving speed v of the vertical axis 2 at this time, and the voltage corresponding to the rated speed Vs are transferred to the comparator 34.
When the moving speed v is less than the rated speed Vs, the process returns to the beginning of the brake torque test mode. When the moving speed v is equal to or higher than the rated speed Vs, the relay 36 from the CPU 31 via the relay drive circuit 35 is dropped out, and both contacts A1 and A2 of the relay are opened. As a result, the motor 5 is
The power supply to the brake is cut off, and the brake 6 is activated again. As a result, the movement of the vertical shaft 2 is stopped.

In FIG. 2, the reference numeral 16 indicates a second switch (Y), which is operated by the vertical shaft 2 when the vertical shaft 2 reaches the following position. That is, when the first switch When the vertical axis 2 reaches the end position of the maximum stopping distance, the second switch (Y)
16 is operated by the vertical axis 2. Therefore, the switch (Y) 16 is operated by the vertical shaft 2 at the end of the range in which it must stop when the switch (X) 15 is operated and the vertical shaft 2 enters the emergency stop state.

As mentioned above, when the second switch (Y) 16 is not operated by the vertical axis 2 during the process in which the vertical axis 2 is stopped in the same manner as in the case of an emergency stop, this switch is sent to the CPU via the interface 33.
31, the automatic operation mode is selected by the CPU, and normal operation is performed. Vertical axis 2
In the process where
31, the CPU disables further operation, and informs the control panel 18 of this inoperable situation.
Display on CRT, etc.

In the above explanation, the movable body is the vertical axis 2, but the first arm 3 also has the first switch X (23) and the second arm 3, as shown in FIG.
By providing the switch (Y) 24, the torque of the mechanical brake can be easily checked as in the case of the vertical shaft 2 described above. Also, the second arm 4
The mechanical brake torque can also be checked in the same manner as for the first arm 3.

In the above embodiment, the limit switches 11a, 1
In addition to 1b, 21, 22, the first switch (X) 1
5, 23 and second switches (Y) 16, 24, these first switches (X) 15,
23 as the limit switch 11a, 21, and the second switch (Y) 16, 24 as the limit switch 11
b, 22 may also be used.

As described above, this invention can check the brake torque of the mechanical brake that stops a movable body such as a vertical axis or an arm, so the movable body can be reliably stopped by an emergency stop of the movable body. It is something.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the basic configuration of the present invention.
2 to 6 show one embodiment of the present invention, FIG. 2 is an overall configuration diagram, FIG. 3 is a sectional view taken along line A-A in FIG. 2, and FIG. 4 is a main part. block diagram,
FIG. 5 is a graph showing the operation, and FIG. 6 is a flowchart explaining the operation. 1: Robot body, 2: Vertical axis, 3, 4:
Arm, 5: Motor, 5a: Voltage generator, 6: Brake, 12: Motor, 12a: Voltage generator, 13:
Brake, 15: First switch (X), 16:
2nd switch (Y), 23: 1st switch (X), 24: 2nd switch (Y).

Claims (1)

[Scope of Claims] 1. A motor that moves a movable unit that constitutes a robot, a brake that mechanically brakes the movable body, and a voltage that generates a voltage proportional to the speed of the movement as the movable body moves. a first switch that is operated when the movable body comes to a predetermined position by movement of the movable body; a second switch that is operated by the movable body when the switch has moved the maximum allowable distance from the position where the switch is operated until the brake is activated and the switch is stopped; a detection means for determining that the moving speed of the movable body is equal to or higher than the rated speed by comparing the output voltage of the voltage generator at the time when the voltage generator is operated with a reference voltage corresponding to the rated speed; control means for issuing a command to cut off the power supply to the motor and activate the brake when it is determined that the moving speed is equal to or higher than the rated speed; 1. A control device for an industrial robot, comprising automatic operation permission means that enables switching to an automatic operation mode only when a second switch has not been operated at the time when the robot stops moving.