JPH1133975A - Robot monitoring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a monitoring device for monitoring the operation of a robot by a system different from robot control concerned. SOLUTION: The watching ranges 14 for watching the invasion of a robot are preset near robots 12, the watching ranges 14 are picked up for each specified time by using image pickup means 16, and whether a moving object exists in a part corresponding to the watching range 14 in an image picked up by the image pickup means 16 is judged by an analyzing means. The analyzing means judges the presence or absence of a moving object by detecting the movement of a part corresponding to the watching range 14 in the image. When it is judged that a moving object exists in the watching range 14, supply of power source to the robot 12 is stopped, or warning sound and/or warning light is emitted by providing a warning means for emitting warning sound and/or warning light on a monitoring device, and therefore, generation of abnormalities is preliminarily prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for monitoring a robot such as an industrial robot.

[0002]

2. Description of the Related Art Generally, a robot such as an industrial robot has a monitoring program such as a watchdog timer for controlling the operation inside the robot, and the robot deviates from a desired operation due to a malfunction or disturbance of the operation program. When the robot operates, the robot is determined to be “runaway” and the operation of the robot is stopped or an alarm is issued.

[0003]

However, the monitoring program and the program for controlling the operation of the robot are:
Often controlled by the same CPU, CPU
When an error occurred, the monitoring program sometimes did not operate sufficiently even if the robot ran out of control. Also, since the monitoring program monitors the operation of the robot itself, even if a moving object other than the robot, such as a person or another robot, approaches the robot, it cannot recognize it, and the approaching movement The collision between the object and the robot could not be prevented.

[0004] It is an object of the present invention to monitor the operation of a robot by a different system, and to stop the operation of the robot by stopping the supply of power to the robot when the robot moves out of a predetermined work area and operate. An object of the present invention is to provide a monitoring device capable of issuing an alarm when another moving object approaches a robot and preventing a collision between the moving object and the robot beforehand.

[0005]

In order to solve the above-mentioned problems, a robot monitoring apparatus (10) of the present invention sets a warning area (14) in the vicinity of a robot (12) to warn of the intrusion of the robot in advance. In advance, the guard area (14) is photographed at predetermined time intervals by using the imaging means (16), and a portion corresponding to the guard area (14) in an image photographed by the imaging means (16) is provided. Robot (12)
Analyze whether moving objects are present, including
Determined in (18). The analysis means (18) is a warning area in the screen.
The presence or absence of a moving object is determined by detecting the movement of the portion corresponding to (14). For example, the alert area (1
A moving object can be recognized by generating a motion vector of a portion corresponding to 4) and determining the presence or absence of a non-zero motion vector in the alert area. When the analysis means (18) determines that a moving object exists in the alert area (14), the following control is performed. For example, when the moving object enters in the direction from the robot side to the alert area, the moving object that has entered the alert area (14) is the robot (12), and the robot (12) runs away. Therefore, the supply of power to the robot (12) is stopped. If the moving object enters the robot in a direction toward the robot, since the moving object is a human or another robot, an alarm means (44) for issuing an alarm sound and / or an alarm light to the monitoring device (10). Is provided to emit an alarm sound and / or an alarm light to prevent occurrence of an abnormality.

[0006]

The robot monitoring device (10) of the present invention constantly monitors a warning area (14) set in advance in the vicinity of the robot (12) and detects the movement of an image in the warning area (14). , Generate a motion vector. The motion and the motion vector of the object can be obtained by calculating a difference between image data such as a luminance signal in a warning area between two consecutive frames during the short time Δt. If the motion of the object is detected in the alert area (14), that is, if an image having a non-zero motion vector is detected, the robot (12) or other moving object is located in the alert area (14). Is considered as invading, the supply of power to the robot is stopped, or an alarm is issued.

According to the present invention, even if a failure occurs in the monitoring program inside the robot when the robot runs away, the robot monitors the robot by a separate system. It is possible to prevent a runaway run. In addition to monitoring only the robot, it can also monitor the intrusion of objects such as humans and other robots into the alert area,
By issuing an alarm or the like, a collision or the like can be prevented.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION A robot monitoring apparatus (10) of the present invention
As shown in FIG. 1 and FIG. 2, an image capturing means (16) for capturing an alert area (14) set near the robot (12) and an image captured by the image capturing means (16) are analyzed. Analyzing means (18)
Equipped.

As the image pickup means (16), an image pickup device such as a video camera or a digital still camera can be used.
The belt conveyor (19) is arranged so that the vicinity of the industrial robot (12) arranged along a line such as a factory where products are assembled can be monitored from above. 3A to 3D show images photographed by the imaging means (16). Around the industrial robot (12), each robot (12)
The operable area is set, and around the operable area, an alert area (14) for alerting the robot from entering is set. In the present embodiment, the alert area (1
4) is set as the area behind the robot from the side and the space above it.

The imaging means (16) captures an image (see FIGS. 3A to 3D) including the alert area at every minute time Δt, and transmits an image signal to the analysis means (18). Note that the number of pixels of the imaging means (16) is s × t (where s and t are both positive integers). The minute time Δt is desirably set to the scanning time of one field or one frame or an integral multiple thereof, for example, 1/6.
It can be 0 seconds.

The image taken by the imaging means (16) is
It is input to the analyzing means (18). The image signal input to the analysis means (18) is AD-converted by the AD converter (20).
Next, a luminance signal of only the pixel corresponding to the alert area (14) is extracted from the luminance signal Y in the AD-converted image signal.
As a method of extracting only the luminance signal of the guard area portion, for example, the luminance signal Y has s × t storage units corresponding to each pixel of the image, and corresponds to the guard area (14) set in the image. "1" for the storage unit to perform, and "0" for the other storage units
Is integrated by the AND gate (22) with the data of the area discriminating memory (24) which has been written in advance.
By multiplying by the AND gate (22) with the corresponding storage data of the area discrimination memory (24), the luminance signal outside the alert area is output as zero. The luminance signal that has passed through the AND gate (22) is stored in the luminance memory (25). The luminance memory (25) has s × t storage units corresponding to each pixel of the image, and sequentially stores input luminance signals.

Next, the luminance signal Y 'of the image after the elapse of the minute time Δt is transmitted from the imaging means (16) to the analysis means (18), and is similarly A / D converted. The input luminance signal Y 'passes through the AND gate (22), and similarly, the luminance signal outside the alert area becomes zero and is output.

Next, the difference between the luminance signal stored in the luminance memory and the luminance signal after the time Δt is calculated by a difference circuit (26), and a change in luminance is detected in the image in the alert area (14). .
The luminance difference calculated by the difference circuit (26) is converted into an absolute value by an absolute value conversion circuit (27). "0" if the value is zero
Is determined. The binarized pixel data in the alert area is transmitted to the motion determining circuit (30), and the presence or absence of the moving object is determined.

For example, as shown in FIGS. 3A and 3B, when there is no change in the image in the guard area (18) (movement may occur in a portion other than the guard area as shown in the figure). When there is no moving object in the area, the difference between the luminance signals in the alert area is all zero, and the result of binarization and binarization is also all zero as shown in FIG. 3A-1. This result is transmitted to the motion determination circuit (30). The motion discrimination circuit (30) judges that no motion exists in the alert area since the operation result is "0" for all pixels in the alert area. If the motion discriminating circuit determines that there is no moving object, a difference calculation of the luminance is performed for the next minute time Δt.

As shown in FIGS. 3B to 3D, the alert area (14)
Consider a case in which the tip of the arm (31) of the robot (12) enters. 3B and 3C, when the difference of the luminance signal is calculated by the difference circuit (26), the difference does not become zero because the luminance signal of the corresponding portion in the alert area (14) changes. The result of the difference calculation is converted to an absolute value conversion circuit.
When the value is converted to an absolute value and binarized in (27), as shown in FIG. 3B-1, only the portion where the arm has entered becomes "1", and the other portions become "0". As a result, a motion exists in the alert area, and the motion discrimination circuit (30) determines that "there is a moving object". When the motion judging circuit (30) judges that there is a "moving object", the portion (33) in which the binarized data value is surrounded by "1" is masked by the masking circuit (32), and the center of gravity is calculated. The signal is transmitted to the arithmetic circuit (34). The center-of-gravity calculating circuit (34) calculates the center of gravity of the mask portion, and stores the coordinates in the center-of-gravity memory (36). Next, as shown in FIGS. 3C and 3D, the arm (31) of the robot (12)
4), the difference between the luminance signals is obtained in the same manner, and by the same processing as described above, as shown in FIG. 3C-1, the part where the binarized data value is surrounded by "1" ( 33)
Is masked, and the barycentric coordinates are calculated. The obtained barycenter coordinates and the barycenter coordinates stored in the barycenter memory (36) are transmitted to the barycenter difference circuit (38), and a difference between the barycenter coordinates is obtained. The difference between the coordinates obtained by this difference operation becomes the motion vector (50) of the center of gravity of the moving object (see FIG. 3D-1). The obtained motion vector is used as a direction discriminator.
Sent to (40). The direction discriminating circuit (40) extracts only the directional component in the motion vector, and determines whether the moving direction of the moving object is a direction away from the robot (12) (hereinafter, “outgoing direction”) or a direction toward the robot (12). (Hereinafter, `` entrance direction '')
Is determined.

When the direction discriminating circuit (40) judges that the moving direction of the moving object is the direction away from the robot (12) (outgoing direction), the direction from the robot side is usually determined as shown in FIGS. Since the movement of a moving object into the alert area (14) is considered to be a runaway of the robot (12), the control circuit
(42) cuts off the power supply circuit (43) of the robot (12),
Stop supplying power to (12). On the other hand, the direction determination circuit
If (40) determines that the moving direction of the moving object is the direction (incoming direction) toward the robot (12), the movement of the moving object such as a human or another robot enters the alert area (14). Since there is no runaway of the robot (12), the control circuit (42) transmits a signal to the alarm means (44). The alarm means (44) issues an alarm to the intruding moving object by light or sound according to a command from the control circuit (42). Thereby, collision between the robot and the moving object can be prevented.

In the above embodiment, the intrusion of the moving object into the caution area and the direction of the invasion are detected from the motion vector in the caution area. , The power supply to the robot may be stopped or an alarm may be issued.

The motion vector is represented by a representative point matching method,
It may be determined using a gradient method (gradient method) or the like.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of a robot monitoring device according to the present invention.

FIG. 2 is an explanatory diagram illustrating a state in which a robot is monitored using an imaging unit.

FIG. 3 is an explanatory diagram showing an image of an imaging unit and a difference in luminance in a warning area.

[Explanation of symbols]

 (10) Monitoring device (12) Robot (14) Warning area (16) Imaging means (18) Analysis means

Claims (5)

[Claims] An imaging means (16) for photographing a warning area (14), which is set in the vicinity of a robot (12), for warning of the intrusion of a robot at predetermined time intervals; A robot monitoring device, comprising: analysis means (18) for determining whether or not a moving object exists in a portion corresponding to a caution area. 2. An analysis means (18) detects a motion from a difference between image data of an image portion corresponding to the alert area (14) for a short time Δt, and determines the presence or absence of a moving object in the alert area. The robot monitoring device according to claim 1. 3. The analysis means (18) detects a motion of a moving object by generating a motion vector from a difference between image data of an image portion corresponding to the alert area (14) for a short time Δt, and The robot monitoring device according to claim 2, wherein the presence or absence of an object is determined. 4. When the analyzing means (18) determines that a moving object is present in the alert area (14), the analyzing means (18)
The robot monitoring device according to claim 1, wherein a command to stop supplying power to the robot is transmitted. 5. The analysis means (18) is connected to an alarm means (44) for emitting an alarm sound and / or an alarm light, and the analysis means (18) has a moving object in the alert area (14). 5. The robot monitoring device according to claim 1, wherein when the determination is made, a command to emit a warning sound and / or a warning light is transmitted to the warning means (44).