JP7549862B2 - Door opening/closing control device - Google Patents

Description

The present invention relates to a door opening/closing control device, and more specifically, to a door opening/closing control device that controls the opening and closing of shutters installed at the entrances of buildings such as factories and warehouses.

First, referring to Figures 6(a) and 7(a), a radar detector (radar module) 1 is often used to automatically open and close shutters SD installed at the entrances of buildings such as factories and warehouses.

The radar detector 1 is placed in the blind 2 above the shutter SD, and is intended to detect vehicles V, such as forklifts, approaching the shutter. The shutter SD is required to open for vehicles V, but not for pedestrians (workers inside the building, etc.) H. This is because, although not shown, there is usually a pedestrian entrance adjacent to the shutter SD.

The intensity of the radar reflected wave is stronger for a metallic vehicle V than for a pedestrian H, so a threshold value TH is set between the reflection intensity of a pedestrian H and that of a vehicle V, and the intensity of the radar reflected wave received by the radar detector 1 is compared with the predetermined threshold value TH to determine whether it is a pedestrian H or a vehicle V.

As shown in Figures 6(b) and 7(b), this threshold value TH is set so that radar reflections RV from vehicles V are picked up as detections, but radar reflections RH from pedestrians H are not picked up as non-detections.

However, if the width of the threshold value TH is set wider than the radar reflection wave RH from the pedestrian H in this way, the radar detection range for the vehicle V will be narrowed. In other words, as shown in Figures 8(a) and (b), a problem occurs in that the shutter SD will not open unless the vehicle V approaches the shutter SD to a certain extent.

Patent Document 1 describes a composite door sensor that uses both a radar detector and an infrared detector. In this composite sensor, a first detection area is formed by the radar detector, and a second detection area is formed by the infrared detector close to the first detection area. When an object approaches the second detection area, the second detection area is activated, and conversely, when the object moves away from the second detection area, the second detection area is deactivated.

This prevents the automatic door from malfunctioning due to disturbances such as rain or snow, but it does not solve the problem of the shutter SD not opening unless the vehicle V gets close enough to the shutter SD.

JP 2006-328853 A

The objective of the present invention is therefore to expand the vehicle detection range while not detecting pedestrians in the opening and closing control of shutters installed at the entrances and exits of buildings such as factories and warehouses.

To solve the above problem, the present invention includes a radar detection unit for detecting vehicles, the first detection area being a predetermined distance away from the door that is the object of opening and closing control, an infrared detection unit for detecting pedestrians, the second detection area being an area within the first detection area that is narrower than the first detection area and closer to the door, and a control unit that has a threshold value for the radar reflected wave of the radar detection unit and gives a door open signal to the door opening and closing drive unit when the radar reflected wave exceeds the threshold value, and the control unit changes the threshold value in response to an output signal from the infrared detection unit.

In a preferred embodiment of the present invention, the control unit reduces the threshold value when the infrared detection unit does not detect a pedestrian within the second detection area, and increases the threshold value when the infrared detection unit detects a pedestrian within the second detection area.

More preferably, the control unit gradually increases the threshold value when the infrared detection unit detects that a pedestrian is moving in a direction approaching the door.

The present invention is preferably applied to shutters installed at the entrances and exits of buildings such as factories and warehouses.

According to the present invention, when controlling the opening and closing of shutters installed at the entrances and exits of buildings such as factories and warehouses, it is possible to expand the detection range for vehicles while not detecting pedestrians.

1 is a block diagram for explaining an embodiment of a door opening/closing control device according to the present invention; 6A is a schematic diagram showing a state in which there is no pedestrian in either the first or second detection area; FIG. 6B is a threshold value at that time; (a) is a schematic diagram showing a state in which a pedestrian is located far from the shutter in the first detection area, and (b) is the threshold value at that time. (a) is a schematic diagram showing a state in which a pedestrian approaches the shutter and enters the second detection area, and (b) is the threshold value at that time. (a) Schematic diagram showing the state where a pedestrian is in front of the shutter, and (b) the threshold value at that time. As an explanation of the prior art, (a) is a schematic diagram showing a state in which a vehicle has entered a radar detection area, and (b) is a graph showing the relationship between radar reflected waves from a vehicle and a threshold value. As an explanation of the prior art, (a) is a schematic diagram showing a state in which a pedestrian has entered a radar detection area, and (b) is a waveform graph showing the relationship between the radar reflection wave caused by a pedestrian and the threshold value. 5A and 5B are schematic diagrams illustrating how the radar detection range for a vehicle is narrowed according to the conventional technology.

Next, an embodiment of the present invention will be described with reference to Figures 1 to 5, but the present invention is not limited to this embodiment.

First, referring to FIG. 1, the door opening/closing control device 10 according to the present invention basically comprises a radar detection unit 20, an infrared detection unit 30, and a control unit (CPU) 40.

The radar detection unit 20 is used exclusively for vehicle detection, and may be a commercially available radar module 21 having a radio wave transmission/reception circuit and an antenna. Two radar reflected waves IF1 and IF2 are sent from the radar module 21 to the control unit 40 via amplifier circuits 22a and 22b, respectively. The control unit 40 determines the moving direction of the detected object (approaching or moving away) by observing the phase of the radar reflected waves IF1 and IF2.

The infrared detector 30 is used solely for pedestrian detection and may be of a known type having a light-projecting section 31 including multiple light-projecting elements such as LEDs, and a light-receiving section 32 including multiple light-receiving elements (the same number as the light-projecting elements) such as photodiodes.

The light-projecting elements (LEDs) in the light-projecting unit 31 emit light in sequence and in turn, driven by the drive circuit 31b, and irradiate spot lights onto the floor surface of the monitored area via the split lens 31a. For example, if there are four light-projecting elements and the split lens 31a is a two-split lens, eight spot lights are irradiated onto the floor surface per row. The light-receiving unit 32 receives the light reflected from the floor surface via the split lens 32a, and transmits it to the control unit 40 via the amplifier circuit 32b.

Referring to Figures 2 to 5 together, the door to be controlled to open and close is a shutter SD installed at the entrance of a building such as a factory or warehouse, as in the conventional example described above, and the radar detection unit 20 and infrared detection unit 30 are placed in the blind 2 (or a part equivalent to the blind) at the top of the shutter SD.

The radar detection unit 20 monitors the presence or absence of an object and its direction of movement in a first detection area 20A that is a predetermined distance from the shutter SD. The infrared detection unit 30 monitors the presence or absence of an object in a second detection area 30A that is a narrower area within the first detection area 20A that is closer to the shutter SD.

In this embodiment, the infrared detection unit 30 forms multiple monitoring rows L1 to L5 (five in this example) in the direction away from the shutter SD to detect the moving direction of an object, and when an object is detected in the order of monitoring rows L5 → L4 → L3..., it determines that the object is approaching the shutter SD. Conversely, when an object is not detected in the order of monitoring rows L1 → L2 → L3..., it determines that the object is moving in the direction away from the shutter SD.

The strength of the radar reflected wave RH from a pedestrian H tends to weaken the further away the pedestrian is, so the detection range of the vehicle V can be expanded by changing the threshold value TH of the radar reflected wave strength depending on the location of the pedestrian H.

As shown in FIG. 2(a), when there is no pedestrian H in either the first detection area 20A or the second detection area 30A, the control unit 40 sets the threshold value TH for the radar reflected wave to the minimum threshold value TH1 (narrows the threshold width to the minimum width) as shown in FIG. 2(b).

Next, as shown in FIG. 3(a), even if a pedestrian H steps into the first detection area 20A from outside the detection area, the distance from the shutter SD is still large, so in this embodiment, the control unit 40 continues to maintain the threshold value TH for the radar reflection wave at the minimum value TH1 as shown in FIG. 3(b). However, it is also possible to set the threshold value TH2 slightly larger than the minimum value TH1 (TH1<TH2) and to widen the threshold width compared to the minimum value TH1.

Next, as shown in FIG. 4(a), when a pedestrian H enters the second detection area 30A, the control unit 40 sets the threshold value TH for the radar reflection wave to a value TH3 (TH1, TH2<TH3) that is even larger than the above TH1 or TH2 so as not to pick up the radar reflection wave RH from the pedestrian H as undetected, as shown in FIG. 4(b) (the threshold width is wider than that of TH1 or TH2).

Then, as shown in FIG. 5(a), when a pedestrian H approaches very close to the shutter SD within the second detection area 30A, the control unit 40 sets the threshold value TH for the radar reflection wave to the largest value TH4 (TH3<TH4) (the threshold width is wider than when TH3) so as not to pick up the radar reflection wave RH from the pedestrian H as undetected, as shown in FIG. 5(b).

In this way, when the pedestrian H is not in the first detection area 20A or the second detection area 30A, the threshold value TH for the radar reflection wave is set to the minimum value TH1, so that the vehicle V can be detected, for example, when the vehicle V enters the first detection area 20A. In other words, the detection range of the vehicle V can be widened while the pedestrian H is not detected.

Referring again to FIG. 1, the minimum value TH1 and maximum value TH4 of the threshold value TH for the radar reflected wave, as well as the increase rate of their intermediate values TH2 and TH3, can be arbitrarily set in the control unit 40 via the remote control light receiving unit 41 by the user operating the remote control.

The control unit 40 also has two output circuits 42 and 43. One of these, the output circuit 43, is the output unit of the radar detection unit 20, and when the radar reflected wave RV from the vehicle V exceeds the threshold value TH, it sends a shutter open signal to the opening/closing drive unit (not shown) of the shutter SD. When the vehicle V moves away, it sends a shutter close signal to the opening/closing drive unit.

The other output circuit 42 is the output section of the infrared detection section 30, and for example, when the shutter SD is opened and a vehicle V passes through the entrance of a building to close the shutter SD, if a pedestrian H is detected nearby, it sends a safety signal to the opening/closing drive section to prevent the shutter SD from closing.

The door opening/closing control device of the present invention is suitable for shutters installed at the entrances of buildings such as factories and warehouses, but can also be applied to any automatic door that opens and closes only in response to vehicles and does not respond to pedestrians.

REFERENCE SIGNS LIST 10 Door opening/closing control device 20 Radar detection unit 21 Radar module 30 Infrared detection unit 31 Light projecting unit 32 Light receiving unit 31a, 32a Split lens 40 Control unit (CPU)

Claims (4)

The system includes a radar detection unit for detecting vehicles, the first detection area being a predetermined distance away from a door that is the object of opening and closing control, an infrared detection unit for detecting pedestrians, the second detection area being an area within the first detection area that is narrower than the first detection area and closer to the door, and a control unit that has a threshold value for a radar reflected wave from the radar detection unit and that gives a door open signal to an opening and closing drive unit for the door when the radar reflected wave exceeds the threshold value,
The control unit changes the threshold value in response to an output signal from the infrared detection unit. The door opening/closing control device according to claim 1, characterized in that the control unit reduces the threshold value when the infrared detection unit does not detect a pedestrian within the second detection area, and increases the threshold value when the infrared detection unit detects a pedestrian within the second detection area. The door opening/closing control device according to claim 2, characterized in that the control unit gradually increases the threshold value when the infrared detection unit detects that a pedestrian is moving in a direction approaching the door. A door opening/closing control device according to any one of claims 1 to 3, characterized in that the door is a shutter installed at the entrance of a building such as a factory or warehouse.

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