AU782231B2 - Mobile plant proximity detection and warning system - Google Patents

Description

AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION STANDARD PATENT MOBILE PLANT PROXIMITY DETECTION AND WARNING

SYSTEM

The following statement is a full description of this invention, including the best method of performing it known to me: 1 MOBILE PLANT PROXIMITY DETECTION AND WARNING SYSTEM This invention relates to improvements in systems for detecting the proximity of mobile plant or other moving vehicles or hazards, and then warning people of the presence of such vehicles or other hazards in order to reduce the risk of accidents which could result in injury or death.

Mobile plant including fork-lift trucks, pallet carriers, road transport vehicles, tractors, cranes, excavators, etc. often present a significant injury hazard to personnel when these vehicles are operating in areas where pedestrians may also be present. As these vehicles are often large and heavy, pedestrian collision accidents are generally serious or fatal. There have been other systems in use for detecting and warning of the presence of mobile plant. For example one technique employs one or more fixed linear infra-red beam detectors which trigger an alarm when a beam is broken by a vehicle. Another previous example is the use of a visible flashing hazard light mounted on the vehicle and the use of the vehicle horn (or a reversing beeper) to warn pedestrians of the proximity of the vehicle at high risk areas. A further previous proposal is the use of radio frequency devices such as vehicle mounted transponders and associated fixed detection devices or readers to detect their presence.

S"These previous methods have various disadvantages. In the example in which a fixed infra-red beam sensor is used to generate a pedestrian warning alarm, the main disadvantages are that the alarm can be triggered by pedestrians as well as vehicles, and that coverage of an extended detection area to give a Oe reliable and sufficiently early warning in all instances is difficult. The use of a flashing hazard lamp, horn and reversing beeper fulfil a basic safety role, but have the disadvantages that the hazard lamp may not be visible to a pedestrian 30 at an obscured location such as a doorway, in a corridor or at a comer.

Ambient site noise may mask the audible horn warning because the horn may be sounded on the other side of a doorway, and also the operator may forget to operate the horn at the high hazard locations. Radio frequency transponder based systems have the typical disadvantages of high directionality, and/or restricted range of typically up to a few metres, and difficulty in defining and, or restricting the zone of coverage, which in turn restricts their application to this field. Accordingly, there has not, at the time of writing this report, been any H:\deborahk\keep\speci\71847-OO.speci.doc 18/05/05 la significant world application of radio frequency based technology to fork lift or mobile plant safety warning systems, despite radio based technologies being available for many years.

These problems are addressed by the present invention.

According to one aspect of the present invention there is provided a movement detection and warning system comprising a transmitter for transmitting an infrared signal in association with the occurrence of an event or an object, the signal being adapted for triggering a detector, at least one of said transmitter or detector being moveable with respect to the other, said detector being tuned to only detect the infra-red signal transmitted by the transmitter when the detector is located within a predetermined distance from the transmitter, said detector activating an alarm in response to being triggered by the transmitted infra-red signal thereby providing an early and distinct warning to a person in the vicinity of the detector in order to eliminate or reduce the chance of the person sustaining injury, wherein the infra-red signal is transmitted through substantially 3600 around the transmitter.

20 According to another aspect of the present invention there is provided a method of warning a person of the proximity of an object or event comprising associating the object or event with a transmitter for transmitting an infra-red see 0.: signal through substantially 3600 around the transmitter, the signal triggering a S" detector, said transmitter being mounted on a moveable vehicle, said movable vehicle being movable with respect to the detector, said detector being tuned to only detect the signal transmitted by the transmitter so that when the person o and object or event are located within a predetermined distance from each :00. other the transmitter transmits the signal to the detector such that the detector activates an alarm in order to provide an early and distinct warning to the 30 person in the vicinity of the object or event in order to alert the person to the presence of the object or event.

According to another aspect of the present invention there is provided a method of warning a person of the proximity of an object or event comprising associating the object or event with a transmitter for transmitting an infra-red signal through substantially 3600 around the transmitter, the signal triggering a detector, said transmitter being mounted on a moveable vehicle, said movable H:\deborahk\keep\speci\71847-OO.speci.doc 18/05/05 lb vehicle being movable with respect to the detector, said detector being tuned to only detect the signal transmitted by the transmitter so that when the person or object or event are located within a predetermined distance from each other the transmitter transmits a signal to the detector such that the detector activates an alarm in order to provide an early and distinct warning to the person in the vicinity of the object or event in order to alert the person to the presence of the object or event, wherein the object or event is associated with the transmitter using a movement detection and warning system comprising the transmitter for transmitting a signal in association with the event or object, the signal being adapted for triggering the detector, said detector being tuned to only detect the signal transmitted by the transmitter when the detector is located within a predetermined distance from the transmitter, said detector activating the alarm in respect to being triggered by the transmitted signal thereby providing an early and distinct warning to people in the vicinity of the detectors in order to eliminate or reduce the chances of the person sustaining injury.

According to another aspect of the present invention there is provided a movement detection and warning system for alerting a person to the close proximity of a moving vehicle, said system including a transmitter for 20 transmitting an encoded infrared signal through substantially 3600 round the transmitter for a preset time for triggering a detector, said transmitter being S.mounted on the vehicle so that the transmitter moves in accordance with o movement of the vehicle to as to move with respect to the detector, said encoded infrared signal having a relatively narrow dimension in the substantially horizontal plane and a relatively wider dimension in the substantially vertical plane, said detector being tuned to detect the encoded oiso infrared signal transmitted by the transmitter only when the detector is located within a predetermined distance from the transmitter and the infrared signal has been transmitted for the preset time, wherein when the transmitter is located 30 within the predetermined distance from the detector, an alarm is activated in response to the detector sensing the encoded infrared signal for the preset time so as to provide an early and distinct warning to the person in the vicinity of the vehicle in order to eliminate or reduce the chances of the person sustaining injury.

Referring to one example of its application in Figure 1, the new system provides for a mobile plant 1 proximity detection and pedestrian 7 warning system based H:\deborahk\keep\speci\71847-0O.speci.doc 18/05/05 1C on a new infra-red fan-beam transmitter 2, which is energised and always transmitting a rotating fan-shaped beam of invisible light around the said vehicle whenever the said vehicle is operational. It also provides for new, fixed detectors 3 or 4' owe.

0.6 H:\deborahk\keep\speci\71847-O0.speci .doc 18/05/05 person-mounted beam detectors, which are triggered by the said invisible beam when the fixed detector is within a specified range of the transmitter.

The rotating infra-red transmitter beam effectively provides an invisible 'warning zone' all around the vehicle which may extend up to 10 metres or more in effective radius, depending on the particular transmitter design characteristics.

When one or more of the fixed infra-red detectors 3 detect the encoded infrared transmitter beam, they activate pedestrian audible and or visible alarms via a zone controller 4, which terminates the cables from the detector/s and alarms, and supplies power to the detector and alarm circuits, as well as facilitating pre-setting of the alarm timing characteristics for each detection zone. The alarms may be located remote from where the detection occurred, or integrated into the detector in the case of a small personal detector and alarm. As an example of remote siting, the alarms may be located on a pedestrian walkway that approaches the hazard zone. In this way, pedestrians can be clearly warned of the presence of plant vehicles when the vehicles enter or are in a designated hazard zone, even though the vehicle may not yet be visible to the pedestrian. The invention thus can provide an earlier and more distinct warning to pedestrians, without relying on specific 20 operator actions. The use of a rotating coded infra-red light beam gives pervasive coverage of an entire circular area around the vehicle. In this manner, the detectors will still be triggered when the vehicle approaches from a wide range of different angles.

The new system may be applied, in one embodiment, to improving the safety 25 of pedestrians and mobile plant operations in industrial and other applications. Note that other applications of the invention also include the use of a battery powered version of the transmitter which can be mounted at a hazardous site such as an excavation, and which will trigger small versions of the detector alarm devices which are worn by personnel.

Referring to Figure 2, the invention consists of the following principal components: SoA transmitter 11, which is mounted on and powered by the fork-lift or other plant. This device emits a short range electromagnetic signal 13 with the effective range being adjustable depending on the site requirements. The signal 13 is typically infra -red or other electromagnetic radiation. The invention embodies novel concepts for this transmitter. One embodiment consists but is not limited to the radiation source described; for example, one or a group of infrared Light Emitting Diodes (LEDs) 7 mounted in the central housing rather than a traditional incandescent bulb of a rotating hazard lamp, of the type typically used in industry, or a purpose built equivalent. The LEDs do not themselves rotate, however the illumination from them is directed upwards and strikes a specially shaped reflective mirror 9, which is rotating in the horizontal plane affixed to a turntable 8 driven by an electric motor capstan 12 and belt. The reflective surface of the mirror 9 is shaped especially to give a beam which is narrow in the horizontal plane, but wide in the vertical plane to produce maximum detectable range and beam coverage.

The rotation of the mirror 9 thus sweeps this beam 13 continuously through 360 degrees, such that the emitted radiation may be projected in all lateral directions as further defined by the beam shape, around the transmitter during each revolution. The transmitter may embody a protective glass or plastic cover 11 which is selected to be essentially transparent to the particular radiation wavelength used. In one example, the radiation wavelength is 850 nanometres.

The mirror 9 surface may take several forms, depending on the illumination pattern required for a particular application. In a typical implementation of the invention, the transmitter contains new electronic sub-systems including a power supply and regulator 1, which conditions the direct current supply from the vehicle, and supplies power to the operating circuits. A carrier oscillator 2 generates a square wave signal, in this case 375 kHz, which is then modulated by a modulator 4 with another signal generated by oscillator 3. The modulated 375 kHz signal then drives the infra-red LED driver circuits 5 which produce the modulated output beam 13. The radiation 13 is modulated as 20 described, such that this radiation may be reliably detected by the detector 14 :and discriminated against interfering natural or man-made electromagnetic sources, which would otherwise cause false triggering to occur.

Referring to Figure 2, beam 13 is rotating such that when the transmitter 11 comes within the operating range of the detector, the received electromagnetic signal momentarily falls on photo-detectors 16, after passing through the infra-red translucent protective cover 15. The detector 16 thus receives momentary bursts of infra-red radiation from the rotating fan beam emanating from the transmitter 11. These short bursts of signal are amplified by the photodiode amplifier 19, before being demodulated by demodulator Demodulator 20 separates the encoded 3kHz modulation signal from the original signal. This is then connected to a tuned decoder circuit 21, which is tuned to produce a digital output on state only if a 3 kHz signal burst is sustained for a minimum time, otherwise the output remains in the off state.

The output of decoder 21 is routed to a driver and relay circuit 23, which is connected to zone controller 26 by cable or other suitable means. More than one detector may be used in any particular application, and the output circuit of the detectors may be connected in parallel to one zone controller circuit in the case where more than one detector is used in one hazard zone, or alternatively one or more detectors 24 may be used for different hazard zones. For each hazard zone, the zone controller has an individual alarm circuit, which may contain a timer 25, which permits the on-time of the alarm once triggered to be pre-set for a period of typically up to 10 seconds. This feature effectively masks the intermittent nature of the intermittent triggering bursts 13, and produces continuous rather than discontinuous energisation of the pedestrian warning devices for the duration of the presence of the transmitter in the detection zone. The pedestrian alarm configuration may take many forms, including but not limited to that shown in Figure 2 in which an audible alarm 32, a flashing visible hazard beacon 31, and an illuminated character display sign 33 are used. Mains electrical power 28 is supplied also to a DC power supply 27 in the zone controller 26, which in turn provides power for the detectors. Timers 25 contain a relay or contactor to energise the alarm circuits.

Referring to Figure 4, an alternative novel static embodiment of the transmitter consists of a phased array of closely spaced light emitting diodes 1 arranged in a hemispherical or spherical shape, such that the radiation from each diode is emitted outwards at a different angle from each other one. Each diode would be typically able to emit at a tangent to the hemispherical surface. The radiation pattern and beam angle of each diode is selected to overlay with the other diodes, such that if they were all illuminated at one time, the radiation from the hemisphere would be in all directions, including from below a horizontal line through the unit, extending up to the vertical (directly upwards). In this embodiment, each diode (or a selected group of diodes) would be connected to a driver circuit. Each driver circuit is connected to a digital diode array selection circuit, driven from a pulse generator or more 20 intelligent circuit, such that individual diodes or selected groups of diodes may be turned on and off in sequence. In this way, it is then possible to configure the circuit for particular applications electronically. In one example, a line of LEDs extending from the top central one out to one particular equatorial LED is enabled and turned on, with all other being turned off. A sequencing circuit 25 embodied in the device then allows the next line of LEDs 2 to be illuminated with the first line being turned off. The sequencing circuit may be set up electronically (by selection switches or an intelligent processor etc) to thus illuminate each line or group of LEDs for a preset time, before moving on to the next one. In this way, a moving fan beam (or other pattern depending on 30 the group being selected) is generated, without the need for a mechanical scanning device. Particular groups of LEDs may be skipped or disabled depending on the collective beam shape required, and the sequencing rate can be varied from very low to very high speeds. Also, the angle of scan can be varied electronically, so that the collective beam is transmitted at particular angles only within the 360 degree possible sweep. In this way, the device can be configured to say, only transmit in the forward direction, etc. This transmitter also has applications in other fields. One method of construction of this array is shown in Figure 3, in which each line of LEDs in the array are mounted on an individual circuit board 2 and 5. These have piugs 4 and socket 3 through which the electrical connections are made with the processing systems.

5 The entire system, in one embodiment but not limited to this, constitutes a hazard or proximity warning system, which is capable of signalling the proximity of plant to pedestrians, thus improving the safety of pedestrians.

It is to be understood that, if any prior art publication is referred to herein, such reference does not constitute an admission that the publication forms a part of the common general knowledge in the art, in Australia or any other country.

In the claims which follow and in the preceding description of the invention, except where the context requires otherwise due to express language or necessary implication, the word "comprise" or variations such as "comprises" or "comprising" is used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the invention.

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Claims (32)

1. A movement detection and warning system comprising a transmitter for transmitting an infra-red signal in association with the occurrence of an event or an object, the signal being adapted for triggering a detector, at least one of said transmitter or detector being moveable with respect to the other, said detector being tuned to only detect the infra-red signal transmitted by the transmitter when the detector is located within a predetermined distance from the transmitter, said detector activating an alarm in response to being triggered by the transmitted infra-red signal thereby providing an early and distinct warning to a person in the vicinity of the detector in order to eliminate or reduce the chance of the person sustaining injury, wherein the infra-red signal is transmitted through substantially 3600 around the transmitter.

2. A system according to claim 1, in which the infra-red transmitted signal is a fan shaped beam.

3. A system according to claim 2, in which the fan shaped beam is Stransmitted through the angle of 3600, either continuously, intermittently or pulsed.

4. A system according to any preceding claim in which the infra-red beam is an encoded transmission of infra-red radiation. 25

5. A system according to any preceding claim in which the infra-red l: beam is transmitted through 3600 by rotation.

6. A system according to any preceding claim in which the event or object is movement of a vehicle through a prearranged zone or a vehicle arriving at a predetermined location.

7. A system according to claim 6, in which the vehicle is a mobile plant or industrial equipment.

8. A system according to claim 7, in which the vehicle is a fork-lift truck. H.\deborahk\keep\apeci\71847-OO.speci.doc 18/05/05 7

9. A system according to claim 8, in which the infra-red transmitter is mounted on the fork-lift truck.

A system according to any one of claims 6 to 9, in which the detector is located remote from the vehicle and is triggered in response to detecting the infra-red signal transmitted from the vehicle.

11. A system according to any one of claims 6 to 10, in which the alarm system is activated in response to the detector detecting the presence of the infra-red signal, when the vehicle is located at or within the predetermined distance between the transmitter and the detector.

12. A system according to any preceding claim in which the detector and the alarm are located remote from each other.

13. A system according to any one of claims 6 to 12, in which the vehicle can approach the detector from any horizontal direction.

14. A system according to any one of claims 5 to 13, in which the transmitter includes an encoded infra-red source and associated electronic systems and a rotating mirror contoured to produce the rotating fan shaped S"beam of infra-red light.

A system according to any one of claims 2 to 14, in which the fan shaped beam of infra-red light has a narrow dimension in the horizontal plane and a relatively wider dimension in the vertical plane. o.6:

16. A system according to any preceding claim in which the :transmitter includes a static array of Light Emitting Diodes (LEDs).

17. A system according to claim 16, in which the Light Emitting Diodes are arranged in an array of Light Emitting Diodes for operation in a prearranged manner or sequence to provide in effect a rotating beam of infra-red illumination.

18. A system according to claim 17, in which the Light Emitting Diodes are operated to produce a rotating fan shaped beam of infra-red illumination. H:\deborahk\keep\speci\71847-OO.speci.doc 18/05/05 8

19. A system according to any preceding claim in which the detector includes a detector and an alarm.

A system according to any preceding claim in which the detector is powered externally or is provided with its own self-contained power source.

21. A system according to any preceding claim in which the detector is fixed to a substrate at a strategic location or the detector is worn or provided on the apparel or clothing of the person for activation by the infra-red signal when the person having the detector and the transmitter are within the predetermined distance of each other.

22. A system according to any preceding claim in which the alarm includes an audible alarm, a visible alarm, a digital alarm or other warning device, including combinations thereof.

23. A system according to any preceding claim in which the signal transmitted by the transmitter is used to remotely operate an access control device. o°

24. A system according to claim 23, in which the access control device includes a boom gate, a roller door, a swing door, a sliding door, a barrier, or other moving or operating mechanism.

25 25. A method of warning a person of the proximity of an object or event comprising associating the object or event with a transmitter for transmitting an infra-red signal through substantially 360' around the transmitter, the signal triggering a detector, said transmitter being mounted on a moveable vehicle, said movable vehicle being movable with respect to the detector, said detector being tuned to only detect the signal transmitted by the transmitter so that when the person and object or event are located within a predetermined distance from each other the transmitter transmits the signal to the detector such that the detector activates an alarm in order to provide an early and distinct warning to the person in the vicinity of the object or event in order to alert the person to the presence of the object or event.

26. A method of warning a person of the proximity of an object or H,\deborahk\keep\speci\71847-OO.speci.doc 18/05/05 9 event comprising associating the object or event with a transmitter for transmitting an infra-red signal through substantially 3600 around the transmitter, the signal triggering a detector, said transmitter being mounted on a moveable vehicle, said movable vehicle being movable with respect to the detector, said detector being tuned to only detect the signal transmitted by the transmitter so that when the person or object or event are located within a predetermined distance from each other the transmitter transmits a signal to the detector such that the detector activates an alarm in order to provide an early and distinct warning to the person in the vicinity of the object or event in order 1o to alert the person to the presence of the object or event, wherein the object or event is associated with the transmitter using a movement detection and warning system comprising the transmitter for transmitting a signal in association with the event or object, the signal being adapted for triggering the detector, said detector being tuned to only detect the signal transmitted by the transmitter when the detector is located within a predetermined distance from the transmitter, said detector activating the alarm in response to being triggered by the transmitted signal thereby providing an early and distinct warning to people in the vicinity of the detectors in order to eliminate or reduce the Schances of the person sustaining injury.

27. A system according to any one of claims 1 to 24, wherein said S"infra-red signal is transmitted through substantially 3600 around the transmitter in a horizontal plane. 25

28. A system according to any one of claims 1 to 24, wherein said infra-red signal is transmitted through about 1800 in a vertical plane.

29. A system according to any one of claims 1 to 24, wherein said 3 infra-red signal is transmitted through substantially 3600 in a horizontal plane and about 180" in a vertical plane.

A movement detection and warning system for alerting a person to the close proximity of a moving vehicle, said system including a transmitter for transmitting an encoded infrared signal through substantially 3600 round the transmitter for a preset time for triggering a detector, said transmitter being mounted on the vehicle so that the transmitter moves in accordance with movement of the vehicle so as to move with respect to the detector, said H:\deborahk\keep\speci\71847-OO.speci.dc 18/OS/OS 10 encoded infrared signal having a relatively narrow dimension in the substantially horizontal plane and a relatively wider dimension in the substantially vertical plane, said detector being tuned to detect the encoded infrared signal transmitted by the transmitter only when the detector is located within a predetermined distance from the transmitter and the infrared signal has been transmitted for the preset time, wherein when the transmitter is located within the predetermined distance from the detector, an alarm is activated in response to the detector sensing the encoded infrared signal for the preset time so as to provide an early and distinct warning to the person in the vicinity of the vehicle in order to eliminate or reduce the chances of the person sustaining injury.

31. A movement detection and warning system substantially as herein described with reference to the accompanying drawings.

32. A method of warning a person of the proximity of an object or event substantially as herein described with reference to the accompanying drawings. Dated this 19th day of May 2005 EMBRIDGE LAKE PTY LTD By their Patent Attorneys GRIFFITH HACK Fellows Institute of Patent and 25 Trade Mark Attorneys of Australia ea H \deborahk\keep\speci\71847-OO.speci.doc 18/05/05