Patent Application
20240384588
The invention refers to a sensor for automatic doors or automatic gates to detect objects in the vicinity of the door opening according to the preamble of claim 1.
A laser scanner is known from WO 2015/014556 A1, where a rotating mirror is used to produce a scanning field of less than 180°. A similar solution is disclosed in DE 10 2015 013 710 A1.
U.S. Pat. No. 7,349,074 B2 discloses a multiple plane laser scanner having tilted facets, which has a scanning angle of about 90°.
The invention is related to a sensor for use on automatic doors or automatic gates. The sensor works based on pulse echo evaluation of a light-pulse, preferably by evaluating the time-of-flight of emitted and echoed light-pulses, to determine the distance of an object relative to the sensor. The sensor acts on a door controller providing a signal to the door controller so that the door controller can decide whether a certain behavior of the door is required, depending on the detected position of an object or person in the vicinity of the door opening. Such a behavior for a door controller to monitor the safety of a gate is usually to stop or reverse a closing or opening movement.
Usually, automatic doors or automatic gates, especially sliding doors, are monitored in a way that the main closing edges are safeguarded, as they are regarded most hazardous during the closing of the door.
Nevertheless, critical situations may occur also during an opening operation of the door when e.g. a sliding door opens against a wall, for a person can be crushed in between the opening door leaf and the wall.
This situation cannot be properly monitored by the prior art door sensors while monitoring the main closing edges.
It is the object of the invention to improve the scanning area parallel to the door plane by maintaining a high precision of the sensors that are monitoring automatic doors.
The sensor according to the invention comprises at least one rotating mirror, where the rotating mirror has at least three different reflecting emitting mirror facets arranged around its rotational axis. The rotating mirror is driven by a motor. The rotational axis lies normal to a reference plane.
The sensor furthermore comprises a light-pulse generation unit including an emitter. The light-pulse generation unit generates light-pulses which are reflected by the mirror facets. The light-pulses are sent towards the rotating mirror via two different emitting optical paths. Each of the different emitting optical paths comprises at least one optical component. Especially emitters, lenses and mirrors are understood as optical components.
The two emitting optical paths define an incident pulse direction that is the direction of the pulse with which it hits the mirror.
The projections of both incident pulse directions onto the reference plane, which are further called incident beam projections, intersect at an intersecting point with an intersecting angle of less than 160°, preferably between 30° and 160°. An intersection plane is defined through the intersecting point where the intersection plane is normal to the bisectrix of the projections of the incident pulses, where the bisectrix lies in the reference plane.
The intersecting angle is smaller than 160° to allow a scanning field of more than 180°.
The incident beam projections have a width perpendicular to their incident pulse direction, where the intersecting point is preferably at the center line of the incident beam projections. The rotation axis of the rotating mirror intersects the bisectrix, where the rotation axis of the mirror is positioned in a way that the generated scanning field has a scanning angle that is larger than 150°.
Each emitting optical path comprises an optical component being closest to the rotating mirror following the incident beam. These optical components are called “closest optical component” in the following.
To achieve the large scanning angle, the rotating mirror is positioned with its rotational axis being located between the intersection plane and the closest optical components.
The distance of the closest optical component to the intersection plane is determined from the outermost edge of the beam at the closest optical component.
The pulses are sent out of the sensor by reflecting the incident pulses on the emitting mirror facets. These reflected pulses establish a scanning field where these reflected pulses are echoed back by an object in the scanning field. The reflected pulses define a scanning field of a scanning angle that stretches between the outermost reflected beam projections, where the reflected beam projections are the projections of the reflected pulses on the reference plane.
Preferably, the incident pulses can have a direction that is essentially parallel to the reference plane. “Essentially parallel” in this context means parallel with a maximum deviation of 45°, more preferably with a maximum deviation of 30°, more preferably with a maximum deviation of 15°.
The mirror and, accordingly, the rotational axis of the mirror are set in a way that the reflected beam projections from each of both incident optical paths have an innermost reflected pulse that is at least parallel to the bisectrix or even crosses the bisectrix distant to the intersection plane, namely on the side of the scanning field. According to this, the scanning field is an almost continuous field from one outermost reflected beam to the outermost reflected beam on the other side.
The sensor furthermore comprises a rotating mirror that has the same amount of receiving mirror facets as emitting mirror facets, where the light-pulse being echoed back from an object are deflected.
The sensor furthermore comprises a receiving means which receives the light-pulse being echoed back by an object in the scanning field where the echoed pulse is deflected by the receiving mirror facet and is then received by the receiving means in a way that it is distinguishable over which emitting optical path the emitted pulse of the echoed pulse was initially sent. The sensor comprises a receiving lens that is positioned in between the rotating mirror and the receiving means. The receiving lens has an optically effective width. The width is preferably the diameter of the lens perpendicular to its optical axis.
Preferably the two receiving optical paths are separate optical paths, where more preferably the receiving means comprises two separate receivers, where each is dedicated to a receiving optical path.
The sensor preferably comprises an evaluation unit that determines the distance of an object by evaluating the time of flight of the light-pulse from its emission to its reception.
The evaluation unit defines a monitored area and determines whether the measured distance is within the monitored area. The evaluation unit can output a control signal to communicate whether an object is located in the monitored area.
Due to the setup according to the invention, a sensor is provided which can scan an area having a scanning angle of at least 160°, providing at least three curtains. The three curtains may be in the same plane or in planes inclined relative to each other.
Due to the invention the sensor can be embodied as a rather small device that provides a high scanning speed and/or high resolution over a large scanning range.
According to a further embodiment of the invention, each of the emitting mirror facets can have a different inclination relative to the rotation axis. The same is valid for the receiving mirror facets. The different inclinations allow the sensor to scan planes that are tilted differently relative to each other. Accordingly, the sensor can scan not only one plane but a three-dimensional space over a large width. E.g., a so called “0°-facet” is parallel to the rotation axis, where a further mirror facet is inclined at +2° relative to the rotation axis and another further mirror facet is inclined at e.g. −2° relative to the rotation axis. According to this example, the angles of +2° and −2° are inclined in the opposite tilt direction to the “0°-facet”. In both cases the absolute angle between the reflective surface and the rotational axis is 2°.
Accordingly, the inclined facets, except the 0° facet, have a tilting axis around which the facets are tilted. Preferably, the tilting axles are at the same height of the facets, more preferably at the middle of the height of the facet. In this case, the circumradius of the mirror can be determined at the height of the tilting axles.
According to a further advantageous embodiment of the invention, the sensor fulfills the subsequently described conditions.
The pulse emitted at a first angular position of the mirror defines a starting angle of mirror rotation for the outermost pulse, with the first mirror facet defining a first mirror line at that angular position.
A first mirror facet intersects the emitted pulse at a second angular position of the mirror to define an end angle for the innermost pulse, the mirror defining a second mirror line at this angular position.
A pulse corridor is defined around the emitting beam projection having the width of the receiving lens.
The pulse corridor on the reference plane is delimited by an inner borderline and an outer borderline, where the inner borderline is on the opposite side of the scanning field relative to the center line of emitting beam projection.
The second mirror line intersects the first mirror line within the pulse corridor.
Furthermore, a first rotation-center line is defined that intersects the intersection point of the outer borderline and the first mirror line, where the angle A(ML1-RCL1) between the first mirror line and the first rotation-center line is A(ML1-RCL1)=(N−2)*90/N, where the rotation-center line crosses the bisectrix, where N is the number of facets.
Furthermore, a second rotation-center line is defined that intersects the intersection point of the inner borderline and the second mirror line, where the angle A(ML2-RCL2) between the second mirror line and the first rotation-center line is defined by A(ML2-RCL2)=(N−2)*90/N, where the rotation-center line crosses the bisectrix.
The rotation-center lines are chosen so that the rotation-center lines define a triangle with the mirror lines, where the mirror lines include an acute angle.
The mirror lines preferably intersect within the pulse corridor.
The inradius of the mirror is at least the distance of the center of rotation to the mirror lines. Since the center of rotation is preferably located on the bisectrix of the two mirror lines, the distance to both mirror lines is preferably the same.
The rotational axis is located essentially at the intersection of the rotation-center lines.
A sensor with a configuration that meets these conditions provides a large scanning field at a very small possible device size.
According to a further advantageous embodiment of the invention the number of facets N of the mirror is three, four or five. This number N of emitting facets allows a scanning range of about 180° and more, maintaining a reasonable device size.
According to a further embodiment of the invention the previously described door sensor comprises a housing, where the housing comprises a curved window that is transparent for the emitting pulse, as well as for the receiving pulse. The curved window stretches from a start angular position to an end angular position, where the rotational axis of the rotating mirror is located between the line connecting the start position and the end position (of the curved window) and the curved window at the angular position centered between the start angular position and the end angular position of the curved window. The window is not necessarily continuously transparent but may comprise a non-transparent part in its middle. This setup makes it possible to scan a scanning range of about 180° and more by keeping the device size of the sensor rather small.
According to a further embodiment of the invention, the sensor is embodied in a way that the sensor comprises an optical feedback component which can guide a beam from the emitting optical path to the receiving optical path at a certain angular rotation position of the mirror, namely a feedback position.
This allows to transfer the emitted beam from an emission part to a reception part of the sensor. The emission and reception part are optically shielded from one another to avoid stray light influence from the emission to the reception part.
The rotating mirror can advantageously comprise at least one mirror facet having a width so that the emitting beam is reflected by the mirror facet at the feedback position to hit the optical feedback component.
The sensor can comprise an optical feedback determination unit to determine the properties of the emitted pulses that are not echoed back by an object in the scanning field.
The optical feedback component can be positioned between the rotating mirror and the curved window. In this case the optical feedback components are placed at an angle relative to the emitting beam that is larger than that of the innermost beam.
Alternatively, particularly by having three mirror facets, the optical feedback can be at a position in between the incident optical paths. In this case the optical feedback component does not lead to a shadowing effect in the scanning field.
According to a further improvement of the invention, the first emitting optical path and the corresponding receiving optical path are positioned one atop the other, as seen in a direction orthogonal to the reference plane.
In case that the emitting optical path and the receiving optical path are arranged one atop the other, the mirror also comprises the emitting mirror facets and the receiving mirror facets that are parallel to each other. Preferably, an optical shielding is present between the emitting mirror facets and the receiving mirror facets.
Advantageously, such a rotating mirror is embodied as a one-piece element driven by a single motor. This has the advantage that no special synchronization is necessary between the emitting and the receiving part.
According to a further advantageous aspect of the invention, the width of at least one facet is larger than that of the other facets. The angular optical feedback position of the rotating mirror is then set to an angular position at which the enlarged part of the facet is hit by the emitting pulse and is then reflected to an optical feedback component. The optical feedback component can comprise a mirror and/or an optical fiber and/or a prism.
A further aspect of the invention relates to an automatic door or gate.
An automatic door or gate comprises at least one leaf that is at least partially covering a door opening. The at least one leaf is driven by a motor which is controlled by a door controller, where control signals are fed to the door controller to act on the motor to e.g., stop or reverse the current motion.
Commonly the door controller comprises input ports that are separate inputs for each function, e.g., “reopen”, “stop” or “reverse”, where the control is triggered by closing or opening an input switch connected to the port.
Preferably, the input switch is part of the sensor that triggers dedicated switches due to a certain detection situation.
Alternatively, the signal can be communicated to the door controller via a bus system, preferably CAN-Bus.
The automatic door or gate according to the invention comprises a sensor having two light-pulse echo units and one rotating mirror and an evaluation unit determining a position depending on the detection of an object within the combined scanning field provided by two light-pulse echo units, where each optical light-pulse echo unit comprises an emitting and receiving unit. The two light-pulse echo units provide a light path via the rotating mirror, where the combined scanning field provided by both optical light-pulse echo units has a scanning angle of more than 160° and preferably provides a region that is monitored by both optical light-pulse echo units.
Accordingly, the common scanning field is a combination of the two scanning areas provided by the two light-pulse echo units.
Since there is a mechanically defined relation between the two scanning fields by using the common rotating mirror, this allows a very precise measurement of an object position within the scanning field. This is important especially for small objects like fingers, or the like.
Due to an evaluation of the overlapping region of the two scanning areas a masking effect can be reduced. The coverage can be improved as well, as there is no angular derivation in the setup of different laser scanners.
The sensor can preferably be embodied as previously described in detail.
Sensors to safeguard automatic doors or gates are mounted either on the door frame, on the leaf of the door or gate or in the vicinity of the door or gate, respectively.
Such sensors submit a detection status to the door controller, where the door controller, which has knowledge of the current operation mode of the motor and may even have knowledge of the current position of the door leaf, may control the door or gate depending on the detection status information.
According to a further embodiment of the automatic door, the door can be of a swing door type, either of a single leaf or double leaf type. The swing door leaf may comprise a sensor according to the invention that is attached to the door leaf in a way that it monitors the main closing edge as well as the secondary closing edge at the same time.
In this case two danger zones can be monitored with the wiring effort of connecting only one sensor device.
According to a further embodiment of an automatic gate, the gate can be of the swing gate type. This could be a single leaf type or double leaf type. As in difference to swing doors the top edge of the leaf can be of a lower height. By providing a sensor of a detection range of more than 180°, it is possible to fully monitor the hinged area up to the top although the sensor device might be placed below the top edge of the leaf. This could, e.g., be in the middle of the leaf as viewed in its lateral extension.
According to a further embodiment of the invention, the automatic sliding door can be of a single leaf or double leaf type. The sensor is preferably attached to the door frame and monitors the opening on the one side of the sensor and the secondary closing edge on the other side.
An automatic sliding door of the double leaf type comprises two automatically driven sliding door leaves, where the scanner is mounted atop the sliding door leaves and provides at least one curtain that extends in vertical direction generally parallel to the door leaves or in a very acute angle relative to the door leaves. The door leaves each have a main closing edge and a secondary closing edge, where the scanning field covers the position of the main closing edges in a fully closed state of the door as well as the position of the secondary closing edges in a fully open state of the door.
The sensor preferably provides at least three subsequent zones in width direction, where the scanner has a first secondary closing edge zone, a main zone, and a second secondary closing edge zone. A detection event in the first secondary closing edge zone leads to a first signal to trigger a first action on a door controller, a detection event within the main zone leads to a signal to trigger a second action being different from the first action and a detection event in the third zone leads to a signal to trigger a third action being different to the second action. The third action can be different to the first action or the same as the first action.
Preferably the first action is a stop action and the second is a reverse action.
Preferably the door sensor is embodied as previously described.
Further advantages, features and potential applications of the present invention may be gathered from the description which follows, in conjunction with the embodiments illustrated in the drawings.
Throughout the description, the claims and the drawings, those terms and associated reference signs will be used as are notable from the enclosed list of reference signs. In the drawings is shown
Furthermore, the sensor 10 comprises two separate optical components that are embodied as pulse generation units 18a, 18b emitting laser pulses along an emitting optical path to be reflected on the emitting mirror facets, 14a to 14e.
The emitting optical paths 20a, 20b are embodied in a way that they provide an incident beam direction the pulses have before they can be reflected by the mirror 12. An emitting beam 22a can be sent along the first optical path 20a and another beam can be sent along the second optical path 20b. In
It is further derivable from
As can be seen in
According to the invention, there is a distance D between the intersection plane P and the rotation axis A to the emitting side. This setup allows to project an almost continuous scanning field over a large angular range providing multiple scanning curtains.
The inradius of the facets of the rotating mirror is at least the distance of the center of rotation to the mirror line.
The rotation-center lines RCL1, RCL2 are chosen in a way that each rotation-center line RCL1, RCL2 defines a triangle with the mirror lines ML1, ML2, where the mirror lines ML1, ML2 include an acute angle. The mirror lines ML1, ML2 cross inside the corridor between the outer border line OBL and the inner border line IBL.
There are at least two optical components in each optical path, namely in the emitting optical path a pulse generation unit 68a, 68b and a mirror 72a, 72b. Each emitting optical path comprises an optical component in form of a mirror 72a, 72b that deflects the emitted beam to generate an incident optical path in a way that the intersection angle IA between the two incident optical paths is 45°, in this case. In this arrangement, the mirrors 72a, 72b are the closest optical components to the rotating mirror along the optical path.
The echoed pulse is guided along the receiving optical path, which comprises optical components being mirrors 66a, 66b and receivers 62a, 62b. The mirror 72a and 66a can be manufactured as a single reflective part. So can the mirrors 72b and 66b. Preferably, there is an optical shielding between the mirrors 66a, 72a or attached to the single reflective part, dividing these two mirrors.
The incident beam projections cross at an intersection plane P. The rotation axis is parallel to this intersection plane and is distant to the intersection plane P.
As can be seen from
The sensor 40 comprises optical feedback components 74a, 74b guiding the emitted beam to the receivers 62a, 62b.
There is an opening in the non-transparent housing 56 and the transparent housing 58 stretching from the first angular position 60a to 60b that is smaller than the maximum extension of the transparent housing 58 in the same direction. Both housings 56, 58 can be part of a single housing of the device.
The outermost beams OBa, OBb lie at +45° and −45° relative to the bisectrix; accordingly, the scanning field has a range of 270°.
The intersection point is defined by the intersection of the bisectrix BS with the center line CL52a incident beam projection. The setup is symmetric to the bisectrix.
The minimum of the inradius of the mirror 42 is then at least the distance of the center of rotation A of the mirror 42 to the mirror lines ML1 and MU.
According to such a setup, a device can be provided having a small size and a rather huge scanning field.
Zone B is monitored to prevent an object from being crushed between the main closing edges 88a, 90a of the two door leaves 84, 86.
Accordingly, the door controller of the automatic door is influenced in a way that it stops or reverses the movement of the door leaves depending on the motion direction of the door and the zone where an object is detected.
The evaluation unit 94 evaluates the position of an object within the scanning field and will then trigger an output port 96 to act on a control unit 98 to influence the motor 100 driving the leaf.
The evaluation unit 94 can trigger different signals depending on the detection of an object within a predefined zone of the scanning field.
This schematic basic setup as described with regard to
According to the invention a very large scanning area can be monitored in a very precise way by a single sensor 92, being part of an automatic door or an automatic gate.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2021 118 240.9 | Jul 2021 | DE | national |
This application is a national stage application filed under 35 U.S.C 371 of International Application No. PCT Application No. PCT/EP2022/069801 filed Jul. 14, 2022, which claims priority to German Patent Application No. 10 2021 118 240.9 filed Jul. 14, 2021. The disclosures of the above-referenced applications are incorporated herein by reference in their entireties.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2022/069801 | 7/14/2022 | WO |
