JP6367100B2 - Area monitoring sensor - Google Patents

Description

  The present invention relates to an area monitoring sensor, and more particularly to an improvement in an optical scanning type area monitoring sensor that receives detection light reflected by an object and detects an intruder in a monitoring area.

  The area monitoring sensor is a safety device that detects an intruder that has entered the monitoring area, such as a person, and generates a stop signal for stopping the operation of an external device such as a machine tool (for example, Patent Document 1 and 2). For example, the area monitoring sensor generates a detection signal by receiving a light projecting unit that generates detection light, a scanning unit that scans the detection light in the circumferential direction around the rotation axis, and the detection light reflected by the object. A light receiving portion. Detection of an intruding object is performed by obtaining the distance to the object based on the detection signal and specifying the two-dimensional position of the object from the distance to the object and the scanning angle of the detection light.

JP 2008-298646 A JP 2010-178236 A

  The area monitoring sensor described above includes an external input / output port to which a safety control device such as a PLC (programmable logic controller) is connected, and a safety control signal is output from the external output port to the safety control device. The safety control signal includes either one of an operation permission signal that permits the operation of the external device and an operation non-permission signal that does not permit the operation of the external device, and is generated based on the detection result of the intruder.

  Some area monitoring sensors can set a plurality of monitoring areas having different positions and shapes. In this type of area monitoring sensor, one of the monitoring areas is designated as the monitoring execution area, and the detection result for the monitoring execution area is output to the safety control device as a safety control signal. The monitoring execution area is changed to another monitoring area based on an area selection command from the safety control device. In such a conventional area monitoring system, it has been impossible to simultaneously obtain detection results for a plurality of monitoring areas in the safety control device. For this reason, there is a problem that a time delay of at least one scan occurs before the detection result of another monitoring area is acquired.

  The present invention has been made in view of the above circumstances, and provides an area monitoring sensor capable of acquiring detection results for two or more monitoring areas without causing a time delay in a safety control device. With the goal.

  An area monitoring sensor according to a first aspect of the present invention includes a light projecting unit that generates detection light, a scanning unit that scans the detection light in a circumferential direction along a scan plane that is centered on the rotation axis and intersects the rotation axis. A light receiving means for receiving the detection light reflected by the object and generating a detection signal; a distance calculating means for obtaining a distance to the object based on the detection signal; a distance to the object; and Intrusion detection means for detecting an intruder in the monitoring area based on the scanning angle of the detection light, and detection result transmission means for periodically transmitting the detection result of the intrusion detection means to the safety control device, the intrusion Each time the detection means scans a predetermined scanning range, the presence or absence of an intruder is determined for two or more monitoring areas, and a determination result for each monitoring area is generated. Configured to transmit to the safety control device as a detection result of the above discrimination result.

  According to such a configuration, since the determination result for each monitoring area is periodically transmitted to the safety control device, the safety control device obtains detection results for a plurality of monitoring areas without causing a time delay. can do.

  In addition to the above configuration, the area monitoring sensor according to the second aspect of the present invention is configured such that the detection result transmission unit transmits the monitoring area determination result to the safety control device every time the scanning range is scanned. . According to such a configuration, since the detection result of the intruder can be updated for each scan, the time lag from when the intruder enters the monitoring area until the intruder is detected can be shortened. it can.

  In the area monitoring sensor according to the third aspect of the present invention, in addition to the above-described configuration, the intrusion detection unit may distinguish an intruding object with respect to a part of the monitoring area by changing the angular resolution or the distance resolution from other monitoring areas. Configured to do. According to such a configuration, it is possible to reduce the processing load of intrusion detection while ensuring the detection accuracy for some of the monitoring areas.

  An area monitoring sensor according to a fourth aspect of the present invention includes, in addition to the above configuration, a moving body detection unit that detects a moving body that moves within the monitoring area based on a detection result of the intrusion detection unit. However, in some pre-specified monitoring areas, intruders are identified by excluding moving bodies that move at a speed exceeding the judgment threshold, and in other monitoring areas, intruders are not detected. It is comprised so that discrimination | determination may be performed. According to such a configuration, it is possible to improve the detection accuracy for some monitoring areas while suppressing an increase in the processing load for intrusion detection.

  In addition to the above configuration, the area monitoring sensor according to the fifth aspect of the present invention includes an operation permission signal for permitting the operation of the external device and an operation disapproval signal for not permitting the operation of the external device based on the detection result of the intrusion detection means. Safety detection signal generation means for generating a safety control signal comprising either one of the above and an external output port for outputting the safety control signal to which the safety control device is connected via a wiring cable, and the detection result A transmission means is comprised so that the discrimination | determination result of the monitoring area more than the number of the said external output ports may be transmitted to the said safety control apparatus. According to such a configuration, the safety control device can acquire detection results for a plurality of monitoring areas without increasing the number of input / output ports.

  According to the present invention, it is possible to provide an area monitoring sensor capable of acquiring detection results for a plurality of monitoring areas without causing a time delay in the safety control device.

It is the perspective view which showed one structural example of the area monitoring apparatus 1 containing the area monitoring sensor 10 by embodiment of this invention. It is the perspective view which showed the example of a structure of the production system in which the area monitoring sensor 10 of FIG. 1 was installed. It is the figure which showed the structural example of the area monitoring sensor 10 of FIG. FIG. 4 is a diagram showing an example of the operation of the area monitoring sensor 10 in FIG. 3, and shows a case where three areas B1 to B3 are designated as the monitoring area 3. It is the block diagram which showed an example of the function structure in the area monitoring sensor 10 of FIG.

  First, a schematic configuration of an area monitoring sensor assumed by the present invention will be described below with reference to FIGS.

<Area monitoring device 1>
FIG. 1 is a perspective view showing a configuration example of an area monitoring apparatus 1 including an area monitoring sensor 10 according to an embodiment of the present invention. In the figure, an area monitoring sensor 10 capable of separating the display unit 110 from the measurement unit 120 is shown.

  The area monitoring device 1 includes an area monitoring sensor 10 that detects an intruder in the monitoring area, and a setting data creation device 20 that generates setting data for the area monitoring sensor. The area monitoring sensor 10 and the setting data creation device 20 are connected via the communication cable 2.

  The setting data creation device 20 is a terminal device such as a personal computer, and includes a screen display unit 21, a keyboard 22, and a mouse 23, and an application program for an area monitoring sensor is installed. The setting data includes area setting information for specifying a monitoring area and operation setting information for specifying an operation condition of the area monitoring sensor 10.

  For example, the monitoring area is specified as an area surrounded by a graphic connecting these vertices by designating two-dimensional positions of two or more vertices. The operating conditions include intrusion detection resolution and response time, OSSD (described later) output form, EDM (external device monitor) function enabled or disabled, and the like. The setting data creation device 20 generates setting data based on a user operation and transmits it to the area monitoring sensor 10.

  The area monitoring sensor 10 monitors the monitoring area based on the setting data received from the setting data creation device 20. The area monitoring sensor 10 is an optical scanning safety sensor and includes a display unit 110 and a measurement unit 120. The measurement unit 120 is a head unit installed in the vicinity of the danger source, scans the detection light, receives the detection light reflected by the object, and obtains the distance to the object. The display unit 110 is an interface unit that receives a user operation and displays the operation state of the measurement unit 120 on a screen.

<Production system>
FIG. 2 is a perspective view showing a configuration example of a production system in which the area monitoring sensor 10 of FIG. 1 is installed. In this production system, a transfer device and a work robot A1 are arranged in an area partitioned by a protective fence A2, and an area around the mechanical equipment such as a work area of the work robot A1 is set as a monitor area 3, and the inside of the monitor area 3 Are detected by the area monitoring sensor 10.

  The area monitoring sensor 10 monitors the monitoring area 3 by scanning the detection light, and detects an intruder such as an operator A3 who operates the control panel of the machine facility. The monitoring area 3 is configured by a region in the installation surface where the area monitoring sensor 10 is installed, for example, a region in a horizontal floor surface. Intrusion detection is performed by receiving the detection light reflected by the object, obtaining the distance to the object, and specifying the two-dimensional position of the object from the distance to the object and the scanning angle of the detection light. Done.

  A detection result indicating the presence or absence of an intruder is transmitted to a safety control device (not shown). The safety control device is a control device that stops the operation of a machine tool such as the work robot A1 that operates around the monitoring area 3 based on the detection result received from the area monitoring sensor 10. For example, the safety control device is a PLC (programmable logic controller) that controls the operation of the machine in accordance with the order and conditions defined by the program.

<Area monitoring sensor 10>
FIG. 3 is a diagram illustrating a configuration example of the area monitoring sensor 10 in FIG. 1, and shows a separation-type safety sensor. (A) in the drawing shows the case where the area monitoring sensor 10 is viewed from the front, and (b) shows the display unit 110.

  The area monitoring sensor 10 includes a display unit 110 that displays various types of information and receives user operations, and a measurement unit 120 that generates detection light and scans the detection light along the horizontal scan plane 4. The display unit 110 is disposed on the upper surface of the measurement unit 120.

  For example, laser light having a wavelength in the infrared region is used as the detection light. The detection light is repeatedly scanned at a constant period. The measurement unit 120 is provided with cameras 121 and 122 for photographing the monitoring area 3 and indicators 123 and 124 for displaying an operation state. Further, a protective cover 126 for protecting the scanning mirror is attached to the scanner unit 125 of the measurement unit 120. The detection light is scanned in the circumferential direction around the rotation axis of the mirror. The scan surface 4 is orthogonal to the rotation axis.

  The cameras 121 and 122 and the indicators 123 and 124 are disposed above the scanner unit 125. That is, the cameras 121 and 122 are arranged above the scan plane 4 in the rotational axis direction. With this configuration, a parallax in the rotation axis direction is generated between the scan plane 4 and the shooting directions of the cameras 121 and 122, so that a camera image overlooking the scan plane 4 can be obtained.

  The cameras 121 and 122 are both imaging devices arranged in the horizontal direction and having different directions, and are arranged on the left and right sides of the measurement unit 120 with the indicators 123 and 124 in the horizontal plane, respectively. . The indicator 123 is an indicator lamp that displays the operation state by color or lighting state. For example, the indicator 123 lights up with different colors depending on whether the OSSD is on or off. An OSSD (Output Signal Switching Device) is a device for safety control output for outputting a safety control signal indicating one of an on state and an off state. The indicator 124 is an indicator lamp that displays various error states by color or lighting state.

  The display unit 110 includes a screen display unit 111, cable connection ports 112 and 113, an operation unit 114, and an indicator unit 115. The screen display unit 111 is a display device that displays an intruder detection result, a monitoring status, and the like on a screen. For example, the screen display unit 111 is an LCD (liquid crystal display) that can display an image taken by the camera 121 or 122 in color.

  The communication cable 2 extending from the setting data creation device 20 is detachably connected to the cable connection port 112. The cable connection port 113 is detachably connected to a wiring cable extending from a safety control device (not shown).

  The operation unit 114 includes two or more operation buttons used for screen switching, menu item selection, and the like. The indicator unit 115 is composed of two or more indicator lamps that display the operation state by color or lighting state, and displays the OSSD output state and the like. The display unit 110 communicates with the measurement unit 120 and can check the detection result and monitoring status of the intruder even at a position away from the measurement unit 120.

  Next, the structure of the characteristic part of the area monitoring sensor 10 according to the present invention will be described below with reference to FIGS.

<Monitoring area 3>
FIG. 4 is an explanatory diagram schematically showing an example of the operation of the area monitoring sensor 10 of FIG. 3, and shows a case where three regions B1 to B3 are designated as the monitoring area 3. This figure shows a case where the area monitoring sensor 10 is installed on a horizontal floor surface and the monitoring area 3 is designated by defining coordinate axes on a horizontal plane.

  For example, orthogonal coordinates with the area monitoring sensor 10 as the center, the front-rear direction of the area monitoring sensor 10 as the Y axis, and the left-right direction orthogonal to the Y axis as the X axis are determined. The monitoring area 3 is specified as a two-dimensional area surrounded by a graphic connecting a plurality of vertices by designating the position of the vertices using orthogonal coordinates. Alternatively, the monitoring area 3 is specified as a sector area centered on the area monitoring sensor 10 by designating a distance from the center and an angle range.

  In the area monitoring sensor 10, two or more areas having different positions, shapes, or sizes can be designated as the monitoring area 3. The region B1 is a pentagonal region with the area monitoring sensor 10 as one of the vertices. The area B <b> 2 is a fan-shaped area centering on the area monitoring sensor 10. The area B3 is a quadrangular area with the area monitoring sensor 10 as one vertex.

  The detection light is emitted outward in the radial direction with the area monitoring sensor 10 as the center, and is scanned in the circumferential direction along the horizontal plane. The area monitoring sensor 10 can monitor a scanning range 5 exceeding an angle of 180 °.

  In this area monitoring sensor 10, every time a predetermined scanning range 5 is scanned, the presence / absence of an intruder is determined in the areas B <b> 1 to B <b> 3 designated as the monitoring area 3, and the determination result for each monitoring area 3 is detected. As a result, an operation of transmitting to the safety control device is performed.

  By configuring in this way, the determination result for each monitoring area 3 is transmitted to the safety control device, so that the safety control device acquires detection results for a plurality of monitoring areas 3 without causing a time delay. be able to.

  FIG. 5 is a block diagram showing an example of a functional configuration in the area monitoring sensor 10 of FIG. The area monitoring sensor 10 includes a setting data storage unit 130, a light projection control unit 131, a light projection unit 132, a scanning unit 133, a rotary encoder 134, a light receiving unit 141, a distance calculation unit 142, an intrusion detection unit 143, and a detection result transmission unit. 144, a safety control signal generation unit 145, an external output port 146, and a moving body detection unit 147.

  The setting data storage unit 130 stores setting data received from the setting data creation device 20. The light projecting unit 132 is a light source device that generates detection light and emits the detection light toward the scanning unit 133. The scanning unit 133 is a scanner that scans the detection light in the circumferential direction along the scan plane 4 that intersects the rotation axis with the rotation axis as the center, and directs the detection light incident from the light projecting unit 132 toward the object. A reflecting mirror (not shown) and a drive unit for rotating the mirror are included.

  The light receiving unit 141 receives the detection light reflected by the object and generates a detection signal. The rotary encoder 134 is a rotation detection device that detects the rotation angle of the mirror of the scanning unit 133 and generates a rotation pulse signal. The light projection control unit 131 controls the light projection unit 132 based on the rotation pulse signal of the rotary encoder 134 and adjusts the light projection timing of the detection light. For example, detection light is emitted every time the mirror rotates by 360 ° / 1000.

  The distance calculation unit 142 obtains the distance to the object based on the detection signal from the light receiving unit 141 and outputs the measurement result to the intrusion detection unit 143. For example, the distance from the area monitoring sensor 10 to the object is obtained by measuring the TOF (Time Of Flight) of the detection light. Specifically, the distance to the object is calculated by comparing the detection signal with the rotation pulse signal of the rotary encoder 134 and specifying the delay time from when the detection light is projected until it is received. The delay time of light transmission / reception is measured every time detection light is emitted.

  The intrusion detection unit 143 detects an intruder in the monitoring area 3 based on the setting data in the setting data storage unit 130, the distance to the object, and the scanning angle of the detection light, and the detection result is detected. The data is output to the transmission unit 144 and the safety control signal generation unit 145. The scanning angle of the detection light is specified based on the rotation pulse signal of the rotary encoder 134. Whether or not the object exists in the monitoring area 3 is determined by specifying the two-dimensional position of the object from the distance to the object and the scanning angle of the detection light.

  The detection result transmission unit 144 performs wireless communication with the PLC 30 and periodically transmits the detection result of the intrusion detection unit 143 to the PLC 30. Each time the intrusion detection unit 143 scans a predetermined scanning range 5, the intrusion detection unit 143 determines the presence or absence of an intruder in two or more monitoring areas 3, and generates a determination result for each monitoring area 3. The scanning range 5 is designated based on the operation setting information of the setting data. The presence / absence of an intruder is determined for all the regions B1 to B3 designated as the monitoring area 3 for each scanning cycle.

  The detection result transmission unit 144 transmits two or more determination results to the PLC 30 as detection results. For example, the detection result transmission unit 144 transmits the determination result of the monitoring area 3 to the PLC 30 every time the scanning range 5 is scanned. That is, the determination result is transmitted to the PLC 30 for all the areas B1 to B3 designated as the monitoring area 3. The detection information transmitted to the PLC 30 may include position information indicating the position of the areas B1 to B3 or the position of the intruder in addition to the determination result for each of the areas B1 to B3.

  By configuring in this way, the detection result of the intruder can be updated for each scan, so the time lag from when the intruder enters the monitoring area 3 until the intruder is detected is shortened. Can do. Note that the configuration may be such that the determination results of the monitoring area 3 are collectively transmitted to the PLC 30 each time the scan results for a certain number of times of 2 or more are accumulated.

  In order to reduce the processing load, the intrusion detection unit 143 discriminates an intruder by changing the angular resolution or distance resolution of a part of the monitoring areas 3 specified in advance from the other monitoring areas 3. Perform the filtering process to be performed. For example, the intrusion detection unit 143 determines an intruder with respect to a part of the monitoring areas 3 with a lower angular resolution than the other monitoring areas 3.

  More specifically, an intruder is usually present in the monitoring area 3 by comparing distance measurement data obtained at every scanning angle of 0.36 ° with area setting information indicating the monitoring area 3. Is determined. On the other hand, with respect to some monitoring areas 3, the presence or absence of an intruder is determined with the angular resolution lowered by thinning the distance measurement data to be compared with the monitoring area 3.

  The monitoring area 3 to be subjected to such filter processing is specified based on the operation setting information of the setting data. Alternatively, the monitoring area 3 to be filtered is automatically specified according to the distance from the area monitoring sensor 10. By configuring in this way, it is possible to reduce the processing load of intrusion detection while ensuring the detection accuracy for some of the monitoring areas 3.

  The moving body detection unit 147 detects a moving body that moves in the monitoring area 3 based on the detection result of the intrusion detection unit 143, and outputs the detection result to the intrusion detection unit 143. Detection of the moving body is performed by comparing the detection results for each scan and tracking the intruder. For example, an intruder that moves along the scan plane 4 is detected as a moving body.

  The intrusion detection unit 143 performs filtering processing for discriminating intruders by excluding moving bodies that move at a speed exceeding the determination threshold Vc for a part of the monitoring area 3 specified in advance in order to improve detection accuracy. In the other monitoring area 3, the intruder is discriminated without detecting the moving body. For example, the monitoring area 3 to be filtered is specified based on the operation setting information of the setting data. Alternatively, the monitoring area 3 to be filtered is designated based on a user operation of the operation unit 114.

  As the determination threshold value Vc, an upper limit of the walking speed is designated on the assumption that a person such as an operator is an intruder. That is, by excluding a moving body that moves at a speed higher than the determination threshold value Vc from the intruder, it is possible to detect only a human intrusion with high accuracy. By comprising in this way, detection accuracy can be improved about some monitoring areas 3, suppressing that the processing load of intrusion detection increases.

  Based on the detection result of the intrusion detection unit 143, the safety control signal generation unit 145 is a safety control signal that includes either an operation permission signal that permits the operation of the external device or an operation disapproval signal that does not permit the operation of the external device. And output to the PLC 30 via the external output port 146.

  The external output port 146 is an interface unit for connecting the PLC 30 via a wiring cable and outputting a safety control signal to the PLC 30. The external output port 146 is configured by OSSD. When there is no intruder in the monitoring area 3, the OSSD is turned on and an operation permission signal is output. On the other hand, when there is an intruder in the monitoring area 3, the OSSD is turned off and an operation non-permission signal is output.

  The detection result transmission unit 144 transmits the determination results of the monitoring area 3 that is larger than the number of external output ports 146 to the PLC 30. By configuring in this manner, the PLC 30 can acquire detection results for a plurality of monitoring areas 3 without increasing the number of input / output ports.

  According to the present embodiment, since the determination result for each monitoring area 3 is periodically transmitted to the PLC 30, the detection results for the plurality of monitoring areas 3 are acquired in the PLC 30 without causing a time delay. Can do.

  In the present embodiment, an example in which the determination results of all the areas B1 to B3 designated as the monitoring area 3 are transmitted to the PLC 30 has been described. However, the present invention provides detection information to be transmitted to the safety control device. However, the present invention is not limited to this. For example, the configuration may be such that the determination result is transmitted to the PLC 30 for two or more monitoring areas 3 selected as the safety control output information among a plurality of areas designated as the monitoring area 3. The selection of the safety control output information is performed based on the operation setting information of the setting data or based on the user operation of the operation unit 114.

DESCRIPTION OF SYMBOLS 1 Area monitoring apparatus 10 Area monitoring sensor 110 Display unit 111 Screen display part 112,113 Cable connection port 114 Operation part 115 Indicator part 120 Measuring unit 121,122 Camera 123,124 Indicator 125 Scanner part 126 Protective cover 130 Setting data storage part 131 Light projecting control unit 132 Light projecting unit 133 Scanning unit 134 Rotary encoder 141 Light receiving unit 142 Distance calculating unit 143 Intrusion detecting unit 144 Detection result transmitting unit 145 Safety control signal generating unit 146 External output port 147 Moving object detecting unit 20 Setting data creating device 30 PLC
2 Communication cable 3 Monitoring area 4 Scanning surface 5 Scanning range A1 Work robot A2 Guard fence A3 Operators B1 to B3 Area indicating the monitoring area

Claims (5)

A light projecting means for generating detection light;
A scanning unit that scans the detection light in the circumferential direction along a scan plane that is centered on the rotation axis and intersects the rotation axis;
A light receiving means for receiving the detection light reflected by the object and generating a detection signal;
A distance calculating means for obtaining a distance to the object based on the detection signal;
Based on the distance to the object and the scanning angle of the detection light, intrusion detection means for detecting an intruder in the monitoring area;
A detection result transmission means for periodically transmitting the detection result of the intrusion detection means to the safety control device,
The intrusion detection means determines the presence or absence of an intruder for two or more monitoring areas each time a predetermined scanning range is scanned, and generates a determination result for each monitoring area,
The area monitoring sensor, wherein the detection result transmitting means transmits two or more determination results as detection results to the safety control device.   2. The area monitoring sensor according to claim 1, wherein the detection result transmitting unit transmits a monitoring area determination result to the safety control device every time the scanning range is scanned.   3. The area monitoring according to claim 1, wherein the intrusion detection unit discriminates an intruding object with respect to a part of the monitoring area with different angular resolution or distance resolution from other monitoring areas. Sensor. Based on the detection result of the intrusion detection means, comprising a moving body detection means for detecting a moving body moving in the monitoring area,
The intrusion detection means determines intruders by excluding moving bodies that move at a speed exceeding a determination threshold for a part of monitoring areas specified in advance, and detects moving bodies in other monitoring areas. The area monitoring sensor according to any one of claims 1 to 3, wherein an intruder is discriminated without any change. Based on the detection result of the intrusion detection means, a safety control signal generation means for generating a safety control signal consisting of either an operation permission signal for permitting the operation of the external device or an operation non-permission signal for not permitting the operation of the external device. When,
The safety control device is connected via a wiring cable, and includes an external output port for outputting the safety control signal,
The area monitoring sensor according to any one of claims 1 to 4, wherein the detection result transmitting means transmits a determination result of monitoring areas larger than the number of the external output ports to the safety control device.

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