JPS59232791A - Safety device for robot - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a safety device that safely stops a robot when it exceeds its operating range.

First, conventional safety devices for robots will be explained. Figure 1 shows the robot and control device (hereinafter referred to as controller)
FIG. 2 is an enlarged view of the lower part of the robot's base, with a part of the signal system marked with □. In the figure, (1) is the robot, (2) is the base of the robot (1), (3) is the vertical axis, and an arm is installed at the upper end so that it can freely rotate at the joint. (4) is a ball screw that moves the vertical axis (3) up and down, and the threaded rod (4a) and Nand (4)
b) It consists of. The threaded rod (4a) is the base (2)
The nut t4bt1 is supported vertically and rotated by the motor (5) via the reducer.
．． It is integrally fixed to the ten-shaft shaft (3). (6) is a brake that applies brakes to the rotating shaft of the motor (5). That is, it applies a brake to the motor (5) speed reduction device and the vertical shaft drive device consisting of a ball screw. In addition,
The vertical shaft (3) moves up and down while being guided by a guide rail fixed perpendicularly to the base (2) and a guide fixed to the vertical shaft (31 and meshing with the guide rail). A detecting body such as an iron piece fixed to a nut (4b), (8) is a limit switch, and in FIG. 1, it is a non-contact switch that is activated by the approach of the detecting body (7).

This non-contact switch (8) is installed near both ends of the operating range of the vertical axis (3), and outputs a signal when the vertical axis (3) operates abnormally and exceeds the operating range. ing. (9) is a controller that controls the operation of the robot (1), and is a peripheral device that includes an operation section, a display section, a CPU, a memory, an interface between the CPU and the robot, and the like. 0I is the wiring connecting the controller (9) and the robot (1). In the above configuration, the vertical axis (3) is normally determined by the control of the controller (9) based on a predetermined program. However, if the vertical axis (3) operates abnormally for some reason, that is, if the limit switch (8) detects that the vertical axis (3) has exceeded the operating range, this detection signal will be sent to the controller. (9
), and a command to stop the operation of the vertical axis (3), that is, a command to drive the brake (6) and a command to stop the motor (5), is output to stop the movement of the vertical axis (3). In this case, the operation stop command for the vertical axis (3) is output via the controller (9), so the operation stop command is output from abnormality detection due to CPU calculation processing time, relay operation delay time, etc. There is a time delay until then, and the vertical axis (3) overruns accordingly, resulting in a longer stopping distance.

Therefore, it is necessary to provide an extra stroke for the movable shaft, and in the case of a vertical axis, the vertical dimension becomes large, and in the case of an arm, there is a problem that the restricted range of arm movement becomes wide.

This invention was made to solve these problems, and by transmitting the detection signal of the limit switch to both the brake and the controller of the drive device that drives the movable shaft, the brake can be activated by the detection signal. The object of the present invention is to provide a safety device for a robot that directly operates the movable axis and also controls the controller to stop the operation of the movable axis.

Hereinafter, one embodiment of the present invention will be described based on the drawings.

FIG. 3 is a side view showing an embodiment of the invention, FIG. 4 is a front view showing an embodiment of the invention, and FIG. 5 is an enlarged view of the lower part of the base in an embodiment of the invention. FIG. 2 is an explanatory diagram with related signal systems added. In the figures, parts with the same reference numerals as in Figs. 1 and 2 indicate the same parts,
In this embodiment, a mechanical limit switch having first and second contacts is used as the limit switch (8), and one contact of the limit switch (8) is connected to the wiring ασ.
j) Connected in series to the drive circuit of the brake (6). The brake (6) performs braking using the force of a spring, and uses an electromagnetic brake that uses an electromagnet to loosen the brake, and the contact of the limit switch (8) is a normally closed contact.

Also, the limit signal from the other contact of the limit switch (8) is input to the controller as in the conventional case.

In addition, (b) is the first arm, (2) is the second arm, 01
is the first joint, (IG is the second joint, αQ is the sixth joint, 07
) is the speed reducer, θ frame is the vertical axis guide rail, and 0 is the vertical axis kite. In Figure 4, Nando's (
4b) IIJ: Nando when the vertical axis reaches the lower limit position (
4b), indicated by a dashed line
) indicates the position of t4b) when the vertical axis reaches the upper limit position.

Next, the operation will be explained. When the vertical axis (3) reaches the boundary position of the operating range of either the vertical side and the limit switch (8) operates, the drive circuit of the brake (6) activates the limit switch (
8) is opened and the brake (
6) is directly driven to stop the vertical axis (3). At the same time, the limit signal from the other contact of the limit switch (8) is input to the controller (9), so
In response to this abnormal signal, the CPU outputs a command to stop the operation of the vertical axis. That is, the stop command for the motor (6) and the brake (5)
) to stop the operation of the vertical axis (3) from the controller (9) as well. In this case, motor (6)
It is sufficient to issue only a stop command for the brake (5), but by also outputting a drive command for the brake (5), the drive for the brake (5) becomes redundant, increasing reliability.

Furthermore, all movements of the robot may be stopped from the CPU.

Although the above description has been made regarding the case where the present invention is applied to the vertical axis, the same effect can be obtained even if the present invention is applied to a movable axis such as an extendable arm. In the case of an electromagnetic brake that performs braking using the force of an electromagnet, a relay is installed near the electromagnetic brake, connected to a controller so as to drive the electromagnetic brake through the contacts of this relay, and connected to the excitation circuit of this relay. This can be done by connecting the limit switch contacts in series.

As described above, according to the present invention, the detection signal of the limit switch directly drives the brake of the drive device that drives the movable axis, so there is no need to take the extra stroke of the movable axis, and the robot If the vertical dimension becomes larger or the restricted range of arm movement becomes wider, the 15 defects can be solved.

[Brief explanation of drawings]

Figure 1 is a front view showing the robot and controller, Figure 2 is a front view showing the robot and controller.
The figure is an enlarged explanatory diagram of the lower part of the base of the robot with a part of the signal system added. Figure 3 is a side view showing an embodiment of the present invention. Figure 4 is a front view showing an embodiment of the invention. , FIG. 5 is an enlarged explanatory view of the lower part of the base in one embodiment of the present invention, with a signal system related to the present invention added. In the figure, (1) is a robot), (21 is a robot (1)
) base, (3) is the vertical axis, (4) is the ball screw, (
5) is the motor, (6) is the brake, (8) is the limit switch, (9) is the controller, and α is the wiring that connects the limit switch (8) and the brake (6). In addition, in the figures, the same reference numerals indicate the same or corresponding parts. Agent Masu Oiwa Figure 1 Customer Figure 2 Nobuko Rimi Figure 3 12 Figure 4

Claims (1)

[Claims] In a robot safety device, a limit switch detects when a movable axis such as the vertical axis of the robot exceeds the operating range, and stops the operation of the movable axis based on this detection signal. , characterized in that, in addition to directly operating a brake that brakes the operation of a drive device that drives the movable axis, a control device that controls the operation of the robot also outputs a command to stop the operation of the movable axis based on the detection signal. robot safety equipment,