AU6610690A - Anti-collision detection and warning system - Google Patents

Description

ANTI-COLLISION DETECTION AND WARNING SYSTEM

This invention relates to systems which will augment safe working practices particularly at (but not limited to) large scale industrial installations and mining sites by providing a method of detection and warning as an aid to preventing accidents involving heavy mobile plant, vehicles, equipment, machinery and the like and other vehicles and personnel.

DISCUSSION OF PRIOR ART

In the past twenty five years the maximum capacity of off-highway haulage vehicles used in surface mining

operations has increased from 65 Tonnes to over 250 Tonnes. Coincident with this, the position of the operator relative to the larger engine and appurtenances coupled with elevated cabin height, has led to a dramatic decrease in the direct visual field of the operator, especially to the right front and behind the vehicle. This lack of direct vision (often referred to as "Blind Spots or "Blind Areas") presents a serious hazard to personnel and vehicles, plant and the like in close proximity particularly in congested areas in mines and quarries.

The scale of operation at modern industrial and mining sites and the sheer size and power of the mobile machinery and vehicles employed has thus led to an alarming increase in serious and lethal accidents and substantial consequential cost both in human life and in material terms. Anticollision or collision avoidance systems of various kinds have been devised over time employing differing methods and technologies with varying degrees of efficacy. These include active systems such as two-way radio and VLF and VHF radio wave techniques and passive systems such as rear vision mirrors, Doppler Radar Systems, infra-red detectors,

reflected light and combinations of two or more of these methods.

Despite these developments there is an urgent need for a system which provides a satisfactory commercial resolution of the problem described above.

In accordance with the present invention, there is provided a system for detecting the presence of a first object relative to a second object comprising transmitter means associated with the first object for transmitting a signal from the first object towards the second object and a plurality of detectors associated with the second object to sense the presence of the signal from the first object and to indicate the direction of approach and proximity of the first object relative to the second object.

In one form of the invention, detectors affixed to heavy mobile plant,vehicles, equipment, machinery and the like sense the presence of incident light emitted by an electro-optical transmitter affixed to another object such as a service vehicle which encroaches the area under

surveillance and indicate to a control unit the direction of the approach and proximity of the object intruding. In this form of the invention, the transmitter emits light pulses at designed rates and intensities to provide the emanating light with a characteristic signature to allow for noise discrimination and distance determination.

Each detector is constrained to receive only that light which emanates from an area of which the shape and size is determined by the physical parameters of the detector.

Each detector contains a light filter to eliminate unwanted frequencies and a transparent shield to protect the device from water and foreign material ingress.

An electro-optical device inside each detector converts filtered light received into an electrical signal which varies in accordance with the intensity of the light

received. This signal is amplified and transmitted via cable to a receiver which discriminates between signals sourced from light emitted by and received from the transmitter and all other sources (e.g. Headlights, sunlight).

Each detector is assigned to observe part of the surface area surrounding and proximate to the object to which it is affixed. The sum of these parts covers the whole of the proximate surrounding area and may overlap.

Each surface area under observation by a detector comprises zones. These zones allow for an alert signal when the outer zone is encroached by a transmitting object and warning signals when the inner zone is encroached. The zones are discriminated by the receiver and are annunciated by audio visual display which indicates the area and zone occupied by the intruding transmitter.

In a further broad form of the invention there is provided an electro-optical detector for use with an anti- collision detection and warning system comprising a housing including a light transmitting shield which allows light received from a light transmitter mounted on a vehicle whose presence is to be detected by said detector to pass through said housing and onto a light detecting transducer located within said housing; said shield comprising a light passing portion bounded by a shaped opaque region; said shaped opaque region defining the field of detection of said detector.

BRIEF DESCRIPTION OF DRAWINGS

In order that the invention may be more readily

understood and put into practical effect, reference will now be made to the accompanying drawings in which:-

Fig. 1 is a front-end view of a heavy hauler to

which is affixed the detectors and receiver and a smaller service vehicle to which is affixed a transmitter according to one embodiment of the invention,

Fig. 2 is a plan view of Fig. 1 showing the areas

under surveillance (detailed as to the zones which the service vehicle has encroached),

Fig. 3 is a side elevation view of the heavy

hauler showing the locations of the detectors at view and the receiver, Fig. 4 is a block diagram of the circuitry of the transmitter and detector apparatus according to one embodiment of the invention,

Fig. 5 is a plan, side elevational and end elevational view of the detector of Fig. 4,

Fig. 6 is a side elevational view of the transmitter of Fig. 4,

Fig. 7 is a diagrammatic view showing the relationships between the detector, the area under surveillance and the transmitter,

Fig. 8 is a schematic diagram of the circuitry within a detector.

Fig. 9 is a combined block and schematic diagram of one channel of the receiver which processes the signal received from a single detector, and,

Fig. 10 is a combined block and schematic diagram of the transmitter.

DETAILED DESCRIPTION OF EMBODIMENTS OF INVENTION

Referring to Figs. 1 and 2, the system of the preferred embodiment includes detection apparatus 2 affixed to a heavy hauler vehicle 5 and a transmitter 1 affixed to a service vehicle 4 located within the inner zone. The light emitted by the transmitter 1 enters the detector 2 on that side of the hauler 5. The electrical signal produced by the detector 2 is sent to the receiver 3 via cable. The receiver 3 processes the signal and indicates which detector 2 has received the signal and the zone in which the transmitter 1 is detected. Detectors 2 may be placed on the hauler such that there would be one at the front, one on each side and one at the rear as illustrated in Fig. 2.

The location of the detectors 2 corresponds with the receiver 3 display such that the direction of an intruding transmitter 1 is indicated with respect to the position of the hauler 5 (see Fig. 2).

The receiver 3 annunciates by sound and visual display the direction and proximity of any intruding vehicle fitted with a transmitter 1.

Construction parameters of the detector 2 and the position of the photo-sensitive device 8 within the detector enclosure determine the geometry of the area under

surveillance are shown in Fig. 5. The detector 2 has an opaque shield 18 incorporating a window 17 which exposes to light a photosensitive device 8. By locating the photosensitive device 8 as shown in Fig. 5 an area approximately rectangular in shape becomes the area under surveillance, as projected in Fig. 7.

The precise location of the detector 2 on the heavy hauler 5 combined with the juxtaposition of the window 17 and the photo-sensitive device 8 determine the actual shape and the extent of the area under surveillance. This allows flexibility in locating the detectors on the hauler for practical installation purposes.

The preferred transmitter 1 shown in Fig. 6 is in the form of a beacon with a waterproof shield 20 transparent to light at selected wavelengths, a base 21 and a light emitter 22 with electronics as per Fig. 10 mounted internally.

The transmitter 1 shown in Fig. 10 includes a low voltage supply 30 feeding an inverter 31 which produces a voltage which is rectified and charges a capacitor 33 to a value determined by a control circuit 32. The control circuit 32 determines the charge on the capacitor 33 and the times at which the light emitter 34 will be triggered. In this way pulses of light of predetermined intensity and timing are emitted.

In the preferred transmitter 1 there are two discrete pulses of differing intensity which delineate the zones under surveillance. The two pulses are repeated at a regular interval.

Light received by a detector 2 passes through the window 17 in the opaque shield 18 and impinges upon a photosensitive device 8 which incorporates a light filter and which is sensitive to light energy within a preselected band of wave lengths, in this case around 840 nanometers and converts the impinging light energy into an electric signal.

An amplifier 23 in the detector 2 amplifies the signal and transmits the amplified signal via cable to the receiver

3. The receiver 3 amplifies the signal further by amplifier

24 where gain adjustment can be made. The signal from amplifier 24 is converted to a pulse by a comparator 25 where the signal is compared to a threshold reference level. The threshold level may be adjusted to exclude random electrical noise induced anywhere in the circuit up to this stage. The first pulse from the comparator 25 is used to trigger a non-retriggerable mono-stable multi vibrator 26 which has its delay set to time out, in the preferred

circuit, at 320 Ms. The output from the comparator 25 is also used by the display logic 29 to indicate the existence of a transmitter 1 in the outer zone. The mono-stable multivibrator 26 output triggers mono-stable multi-vibrator 27 which times out at 60 Ms. The 60 Ms pulse produced here is used as a window through which a second pulse may be detected by comparing the output of the comparator 25 and the mono- stable 27 using the AND gate 28. If a second pulse is received in this window between 320 Ms and 380 Ms then the AND gate 28 outputs a pulse to the display logic 29 which indicates the presence of a transmitter 1 in the inner zone.

The existence of a transmitter 1 in the outer zone is annunciated by the display logic 29 as a green flashing panel light. Inner Zone annunciation is indicated by the same panel light alternatively flashing green and red accompanied by an audible alarm.

The inner and outer zones are differentiated at the comparator 25 by identifying the difference in intensity levels of the two pulses transmitted. When the higher intensity pulse is transmitted and the voltage level produced at the input to the comparator 25 exceeds the threshold level then and only then is an indication given that a transmitter 1 is within the outer zone. The entry to or presence of a transmitter 1 within the inner zone is indicated when the voltage levels produced at the input to the comparator 25 by both pulses exceed the threshold level.

Additional zones may be discriminated and indicated if circumstances require. Various other modifications may be made in details of design and construction without departing from the scope and ambit of the invention.

Claims (21)

1. A system for detecting the presence of a first object relative to a second object comprising transmitter means associated with the first object for transmitting a signal from the first object towards the second object and a

plurality of detectors associated with the second object to sense the presence of the signal from the first object and to indicate the direction of approach and proximity of the first object relative to the second object.

2. The system of claim 1 wherein detectors are affixed to heavy mobile plant, vehicles, equipment, machinery and the like which sense the presence of incident light emitted by an electro-optical transmitter affixed to another object such as a service vehicle which encroaches the area under

surveillance so as to indicate to a control unit the

direction of the approach and proximity of the object

intruding.

3. The system of claim 2 wherein said electro-optical transmitter emits light pulses at predetermined rates and intensities to provide the emanating light with a

characteristic signature to allow for noise discrimination and distance determination.

4. The system of claim 3 wherein each detector is

constrained to receive only that light which emanates from an area of which the shape and size is determined by the physical parameters of the detector enclosure.

5. The system of claim 4 wherein each detector contains a light filter to eliminate unwanted frequencies and a shield to protect the device from water and foreign material

ingress.

6. The system of claim 5 wherein each detector includes an electro-optical device which converts filtered light received by said detector into an electrical signal which varies in accordance with the intensity of the light received.

7. The system of claim 6 wherein said electrical signal is amplified and transmitted via cable to a receiver which discriminates between signals sourced from the light emitted by and received from said transmitter and all other sources.

8. The system of claim 7 wherein each said detector is assigned to view part of the surface area surrounding and proximate to the object to which it is affixed.

9. The system of claim 8 wherein said detectors are arranged so that the whole of the proximate surrounding area is viewed by said detectors.

10. The system of claim 9 wherein each surface area under observation by a detector comprises zones; said zones

allowing for an alert signal when the outer zone is

encroached by a transmitting object and warning signals when the inner zone is encroached by a transmitting object.

11. The system of any previous claim wherein information concerning the approach of a transmitting object is made available on an audio visual display which indicates both area and zone occupied by said transmitting object relative to the object upon which said audio visual display is

mounted.

12. An electro-optical detector for use with an anti- collision detection and warning system comprising a housing including a light transmitting shield which allows light received from a light transmitter mounted on a vehicle whose presence is to be detected by said detector to pass through said housing and onto a light detecting transducer located within said housing; said shield comprising a light passing portion bounded by a shaped opaque region; said shaped opaque region defining the field of detection of said detector.

13. The detector of claim 12 wherein said shield is

generally hemispherical.

14. The detector of claim 13 wherein said shield protrudes from an outer surface of said housing.

15. The detector of claim 12 wherein said light passing portion allows light of around 840 nanometres wavelength to pass in through said housing.

16. The detector of claim 12 wherein said housing further includes signal processing means which receive a signal from said light detecting transducer and process said signal so as to determine whether light received by said detector emanates from a location within an inner zone or outer zone adjacent said detector.

17. The detector of claim 16 wherein said light transmitter emites two discrete pulse trains of light of differing intensity which are used by said signal processing means to delineate said inner zone and said outer zone.

18. A system for detecting the presence of a first object relative to a second object comprising transmitter means associated with the first object for transmitting a signal from the first object towards the second object and a

plurality of detectors associated with the second object to sense the presence of the signal from the first object and to indicate the direction of approach and proximity of the first object relative to the second object; said detectors

receiving line of sight electromagnetic radiation from said transmitter means.

19. A system as claimed in claim 18 wherein said

electromagnetic radiation comprises light spectrum radiation.

20. The system of claim 18 wherein said electromagnetic radiation comprises visible light radiation.

21. The system as claimed in claim 18 wherein said

electromagnetic radiation has a wave length of around 840 nanometres.