WO2004090830A1 - Collision avoidance method and system - Google Patents

Collision avoidance method and system Download PDF

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Publication number
WO2004090830A1
WO2004090830A1 PCT/IB2004/001088 IB2004001088W WO2004090830A1 WO 2004090830 A1 WO2004090830 A1 WO 2004090830A1 IB 2004001088 W IB2004001088 W IB 2004001088W WO 2004090830 A1 WO2004090830 A1 WO 2004090830A1
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WO
WIPO (PCT)
Prior art keywords
vehicle
personnel
mobile equipment
signal
transmitter
Prior art date
Application number
PCT/IB2004/001088
Other languages
French (fr)
Inventor
Anton Lourens
Johan Frederick Tucker
Valery Alexandrovich Kononov
Original Assignee
Schauenburg Flexadux (Pty) Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Schauenburg Flexadux (Pty) Ltd filed Critical Schauenburg Flexadux (Pty) Ltd
Publication of WO2004090830A1 publication Critical patent/WO2004090830A1/en

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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
    • G01S13/74—Systems using reradiation of radio waves, e.g. secondary radar systems; Analogous systems
    • E—FIXED CONSTRUCTIONS
    • E21—EARTH OR ROCK DRILLING; MINING
    • E21F—SAFETY DEVICES, TRANSPORT, FILLING-UP, RESCUE, VENTILATION, OR DRAINING IN OR OF MINES OR TUNNELS
    • E21F17/00—Methods or devices for use in mines or tunnels, not covered elsewhere
    • E21F17/18—Special adaptations of signalling or alarm devices
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
    • G01S13/88—Radar or analogous systems specially adapted for specific applications
    • G01S13/93—Radar or analogous systems specially adapted for specific applications for anti-collision purposes
    • G01S13/931—Radar or analogous systems specially adapted for specific applications for anti-collision purposes of land vehicles
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S13/00—Systems using the reflection or reradiation of radio waves, e.g. radar systems; Analogous systems using reflection or reradiation of waves whose nature or wavelength is irrelevant or unspecified
    • G01S13/88—Radar or analogous systems specially adapted for specific applications
    • G01S13/93—Radar or analogous systems specially adapted for specific applications for anti-collision purposes
    • G01S13/931—Radar or analogous systems specially adapted for specific applications for anti-collision purposes of land vehicles
    • G01S2013/932—Radar or analogous systems specially adapted for specific applications for anti-collision purposes of land vehicles using own vehicle data, e.g. ground speed, steering wheel direction

Definitions

  • THIS invention relates to a method of warning personnel of the presence of mobile equipment and to a system for implementing the method.
  • a known system of this kind comprises transmitters which are carried by personnel, and receivers which are located in vehicles and which are provided with warning lights or buzzers, so that when the transmission of an individual's transmitter is detected by the receiver in the vehicle, the operator of the vehicle is warned visually or audibly of that individual's presence.
  • the warning signal transmitting a warning signal from mobile equipment, the warning signal having a characteristic which varies according to the speed of movement of the vehicle;
  • the warning signal may be transmitted from a vehicle.
  • the method includes transmitting a warning signal from the vehicle.
  • the strength of the warning signal and accordingly the extent of a corresponding warning zone may be increased as the speed of the vehicle increases.
  • the strength of the warning signal is related to a braking distance of the vehicle corresponding to the vehicle speed.
  • the indication which is provided to said personnel may be a visible or audible indication.
  • the receiver may be arranged to control a light used by said personnel, or to operate a buzzer or other similar sound generator.
  • the method may further include transmitting a response signal from said personnel to the approaching mobile equipment, receiving the response signal at the mobile equipment, and providing an indication to an operator of the mobile equipment of the proximity of said personnel.
  • the method may include transmitting a control signal from said personnel to the approaching mobile equipment, the mobile equipment being responsive to the control signal to modify its movement.
  • control signal may be an emergency stop signal to which the mobile equipment responds by stopping.
  • a system for warning personnel of the presence of mobile equipment comprising:
  • a first transmitter associated with mobile equipment and arranged to transmit a warning signal, the warning signal having a characteristic which varies according to the speed of movement of the mobile equipment;
  • At least one first receiver which can be associated with one or more personnel, said at least one first receiver being operable to receive the warning signal from the first transmitter when the mobile equipment approaches said personnel and to provide an output signal indicative thereof;
  • an indicator responsive to the output signal of said at least one first receiver to provide an indication to said personnel of the proximity of the mobile equipment.
  • the mobile equipment may be a vehicle, and the first transmitter preferably has an associated antenna mounted on the vehicle.
  • the system preferably includes a control circuit responsive to an input signal representative of the speed of the vehicle, the control circuit being arranged to control the operation of the first transmitter to vary a characteristic of a signal transmitted by the first transmitter according to the speed of the vehicle.
  • control circuit may be arranged to adjust the power of the signal transmitted by the first transmitter so that the power of the signal increases as the speed of the vehicle increases, so that the extent of a corresponding warning zone is increased accordingly, the power of the signal being related to a braking distance of the vehicle corresponding to the vehicle speed.
  • the system may include a second transmitter associated with said one or more personnel, the second transmitter being arranged to transmit a response signal from said personnel to approaching mobile equipment, the mobile equipment having a second receiver arranged to receive the response signal, and an indicator arranged to warn an operator of the mobile equipment of the presence of said personnel.
  • the second transmitter may be operable to transmit a control signal, the mobile equipment having a control circuit associated with the second receiver which is responsive to the control signal to modify the movement of the mobile equipment, for example, to stop the movement of the mobile equipment.
  • Figure 1 is a schematic plan view of mobile equipment forming part of a system according to the invention in a mine working;
  • Figure 2 is a simplified schematic block diagram of a vehicle based transmitter and receiver of the system
  • Figure 3 is a simplified block diagram of a portable receiver and transmitter of the system.
  • Figure 1 shows a vehicle 10 travelling through a gallery 12 of a mine working. Ahead of the vehicle are three individuals 14, 15 and 16, indicated by crosses. One of them 15 is located around a corner in a gallery 17.
  • the vehicle 10 is equipped with a very low frequency (VLF) transmitter, which continuously transmits a warning signal to alert personnel in the vicinity of the presence of the vehicle while it is moving.
  • VLF very low frequency
  • the vehicle is provided with an omni-directional magnetic loop antenna 18, arranged to transmit the warning signal around the vehicle in all directions. It will be appreciated that, in some applications, it may be preferable to have a directional antenna, or multiple antennas which are selected according to the direction of travel of the vehicle, for example.
  • the vehicle's transmitter arrangement is shown in Figure 2, and includes the transmit antenna 18, a VLF transmitter 20, and a transmission power control circuit 22 which is arranged to receive a speed signal from a speed transducer in the vehicle.
  • the power control circuit is arranged to adjust the output power of the transmitter 20 according to the value of the signal received from the speed transducer, so that the transmitter output power is increased as the speed of the vehicle increases.
  • the intensity of the transmitted warning signal falls off with the cube of the distance from the antenna 18, and the power control circuit 22 can be calibrated accordingly, so that the strength of the warning signal is related to the braking distance corresponding to a given vehicle speed.
  • the power control circuit can be arranged to increase the output power of the transmitter in relation to the input speed signal, or in a stepwise manner with one or more speed threshold settings, or in another desired manner to ensure an adequate warming zone for speed variation.
  • the concentric circles marked "5km/h”, “10km/h”, “15km/h” and “20km/h” indicate schematically the effective range of transmission of the warning signal from the vehicle 10 as the speed of the vehicle increases and the output power of the warning signal transmission is increased accordingly. It will be appreciated that Figure 1 is not drawn to scale in this regard.
  • ⁇ is preferably less than 200 kHz.
  • ⁇ is preferably less than 200 kHz.
  • the propagation of radio waves becomes highly dependent on the environment.
  • the presence of steel structures, cables, pipes and the shape and size of the working itself has a dramatic effect on the coverage obtained by such a system, with the result that a warning zone within which signals can successfully be received has an unpredictable size and shape.
  • UHF signals are used, reflections, multipath propagation and attenuation by stray objects exacerbate the situation. The result is false alarms or reduced system performance.
  • the receiver comprises a miniature loop antenna 24 and an RF receiver circuit 26.
  • the receiver circuit has an output which can operate a relay 28 with its contacts arranged in series with a battery 31 and a lamp 32.
  • the relay has normally open contacts, which are held closed in normal operation by an output signal from the receiver circuit 26, in a fail safe arrangement.
  • the lamp 32 is conveniently a miner's cap lamp and the battery 31 is the associated cap lamp battery carried by a miner.
  • the output of the receiver 26 causes the contacts of the relay 28 to open, typically repetitively at a predetermined rate and for a predetermined period, causing the lamp 32 to flash and thus alerting the wearer of the lamp to the proximity of the vehicle 10.
  • a buzzer, sounder or another indicator can be provided to ensure that the user of the portable receiver unit is alerted to the presence of the vehicle 10.
  • a warning zone is created around the vehicle 10 by the warning signal, with the extent of the warning zone being related to the power of the warning signal.
  • the warning signal could have a constant power, but another characteristic of the signal such as its continuous modulation frequency could be altered in accordance with the measured speed of the vehicle.
  • the warning signal can be modulated with various data.
  • the data could indicate the nature of the vehicle broadcasting the warning signal, its speed, or could comprise information about the nature of the risk posed by the approaching vehicle.
  • Figure 1 a situation is depicted in which the personnel 14 and 15 have been warned (assuming that the vehicle is traveling at 20km/h or more), while the individual 16, who is further away from the vehicle than the others, will not yet have received the warning signal.
  • a portable transmitter is provided together with the * portable receiver worn or used by individual personnel, and a corresponding receiver is located in the vehicle 10, in association with its transmitter.
  • a portable transmitter 30 which has an antenna 36.
  • An optional ID encoder circuit 35 is connected to the transmitter 30 and is arranged to modulate or encode the output of the transmitter 30 with data corresponding to an identity code allocated to the user of the device.
  • the transmitter is connected to the battery 31 or another power supply, and a push button 34 is arranged to power the transmitter and the associated ID encoder 35 when it is depressed.
  • the purpose of the portable transmitter is to permit the user thereof to transmit a response signal to the vehicle 10 when the user has become aware of it. For example, if the user is in a location which makes it difficult to move rapidly out of the path of the approaching vehicle, or is occupied with a task which cannot readily be interrupted, the user may operate the push button 34 to send a response signal to the operator of the vehicle, warning the operator of his/her presence.
  • the response signal is preferably transmitted at a frequency f 2 , which is substantially higher than the frequency fi.
  • a receiver 36 has an antenna 46 and is connected to an alarm circuit 38 with an associated vehicle hooter 40, headlights 42 and a relay 44 arranged to control the vehicle ignition.
  • the receiver 36 output is also connected to a data logger 39, which provides event logging including the time and vehicle speed when signals are received by the receiver 36. This provides a record of events that can be used in case of an accident. For example, if the operator of the vehicle ignores response signals, leading to an accident, this can be established from the data logger record. If a signal is received from the portable transmitter, the hooter 40 and/or the headlight 42 are operated, alerting the driver of the vehicle to the presence of a person whom the driver of the vehicle must take care to avoid.
  • the method and system of the invention transfer the primary responsibility to avoid collisions between a vehicle and individual personnel to the individuals themselves, and assist them in this regard by providing a warning of the approach of a vehicle.
  • an emergency stop signal can be transmitted to the vehicle by pressing the push button 34 a second time.
  • the alarm circuit 38 detects that the same transmitter 30 has transmitted a further signal, and responds to this emergency stop signal by operating the relay 44, the contacts of which can be arranged in series with the vehicle ignition, for example, thus bringing the vehicle to a halt.
  • the relay 44 the contacts of which can be arranged in series with the vehicle ignition, for example, thus bringing the vehicle to a halt.
  • the vehicle will be stopped automatically.
  • the warning signal is preferably a VLF signal.
  • VLF magnetic field penetrates easily through rock, a reliable warning of miners who have obstacles between them and the vehicle, such as the individual 15 in Figure 1 who is around a corner from the vehicle 10, is possible.

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  • Engineering & Computer Science (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Remote Sensing (AREA)
  • Physics & Mathematics (AREA)
  • Mining & Mineral Resources (AREA)
  • General Physics & Mathematics (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Geochemistry & Mineralogy (AREA)
  • Geology (AREA)
  • Electromagnetism (AREA)
  • Emergency Alarm Devices (AREA)
  • Traffic Control Systems (AREA)

Abstract

A system for warning personnel of the presence of mobile equipment such as vehicle is disclosed. A first transmitter is mounted on the vehicle and transmits a warning signal having a characteristic which varies with the speed of the vehicle. Individual personnel are provided with receivers which can receive the warning signal from the first transmitter when the vehicle approaches, and provide an output signal to which an indicator is responsible to warn the personnel of the proximity of the vehicle. Optionally, the personnel are provided with a transmitter enabling them to transmit response signals to a receiver on the vehicle when they receive a warning signal. The response signal alerts the operator of the vehicle to the presence of the personnel. An emergency stop signal can be transmitted by the personnel, if necessary, bringing the vehicle to a halt in an emergency situation. The system avoids the generation of unnecessary alarms in the vehicle, as in most cases personnel can move out of the way of the approaching vehicle. This avoids operator fatigue and helps to maintain the effectiveness of the system.

Description

COLLISION AVOIDANCE METHOD AND SYSTEΪ1
BACKGROUND OF THE INVENTION
THIS invention relates to a method of warning personnel of the presence of mobile equipment and to a system for implementing the method.
Various systems exist which aim to prevent or minimize collisions between mobile equipment, such as vehicles, and personnel. Such systems are particularly desirable in potentially hazardous locations, such as mine workings, construction sites or factories.
A known system of this kind comprises transmitters which are carried by personnel, and receivers which are located in vehicles and which are provided with warning lights or buzzers, so that when the transmission of an individual's transmitter is detected by the receiver in the vehicle, the operator of the vehicle is warned visually or audibly of that individual's presence.
The above described system has been less effective in practice than anticipated. This is thought to be, amongst other reasons, due to increased carelessness of individuals who believe that they are protected by the system, and a form of psychological fatigue experienced by vehicle operators due to frequent operation of the warning system, which may be triggered even when the operator's vehicle passes workers at a safe distance.
It is an object of the invention to provide an alternative method and system for collision avoidance. SUM ARY OF THE INVENTION
According to the invention there is provided a method of warning personnel of the presence of mobile equipment, the method comprising:
transmitting a warning signal from mobile equipment, the warning signal having a characteristic which varies according to the speed of movement of the vehicle;
receiving, via a receiver associated with one or more personnel, the warning signal when the mobile equipment approaches said personnel; and
providing an indication to said personnel of the approach of the mobile equipment.
The warning signal may be transmitted from a vehicle.
The method includes transmitting a warning signal from the vehicle.
For example, the strength of the warning signal and accordingly the extent of a corresponding warning zone may be increased as the speed of the vehicle increases.
Preferably, the strength of the warning signal is related to a braking distance of the vehicle corresponding to the vehicle speed.
The indication which is provided to said personnel may be a visible or audible indication.
For example, the receiver may be arranged to control a light used by said personnel, or to operate a buzzer or other similar sound generator. The method may further include transmitting a response signal from said personnel to the approaching mobile equipment, receiving the response signal at the mobile equipment, and providing an indication to an operator of the mobile equipment of the proximity of said personnel.
In addition, the method may include transmitting a control signal from said personnel to the approaching mobile equipment, the mobile equipment being responsive to the control signal to modify its movement.
For example, the control signal may be an emergency stop signal to which the mobile equipment responds by stopping.
Further according to the invention there is provided a system for warning personnel of the presence of mobile equipment, the system comprising:
a first transmitter associated with mobile equipment and arranged to transmit a warning signal, the warning signal having a characteristic which varies according to the speed of movement of the mobile equipment;
at least one first receiver which can be associated with one or more personnel, said at least one first receiver being operable to receive the warning signal from the first transmitter when the mobile equipment approaches said personnel and to provide an output signal indicative thereof; and
an indicator responsive to the output signal of said at least one first receiver to provide an indication to said personnel of the proximity of the mobile equipment.
The mobile equipment may be a vehicle, and the first transmitter preferably has an associated antenna mounted on the vehicle. The system preferably includes a control circuit responsive to an input signal representative of the speed of the vehicle, the control circuit being arranged to control the operation of the first transmitter to vary a characteristic of a signal transmitted by the first transmitter according to the speed of the vehicle.
For example, the control circuit may be arranged to adjust the power of the signal transmitted by the first transmitter so that the power of the signal increases as the speed of the vehicle increases, so that the extent of a corresponding warning zone is increased accordingly, the power of the signal being related to a braking distance of the vehicle corresponding to the vehicle speed.
The system may include a second transmitter associated with said one or more personnel, the second transmitter being arranged to transmit a response signal from said personnel to approaching mobile equipment, the mobile equipment having a second receiver arranged to receive the response signal, and an indicator arranged to warn an operator of the mobile equipment of the presence of said personnel.
The second transmitter may be operable to transmit a control signal, the mobile equipment having a control circuit associated with the second receiver which is responsive to the control signal to modify the movement of the mobile equipment, for example, to stop the movement of the mobile equipment.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 is a schematic plan view of mobile equipment forming part of a system according to the invention in a mine working;
Figure 2 is a simplified schematic block diagram of a vehicle based transmitter and receiver of the system; and Figure 3 is a simplified block diagram of a portable receiver and transmitter of the system.
DESCRIPTION OF EMBODIMENTS
Figure 1 shows a vehicle 10 travelling through a gallery 12 of a mine working. Ahead of the vehicle are three individuals 14, 15 and 16, indicated by crosses. One of them 15 is located around a corner in a gallery 17.
The vehicle 10 is equipped with a very low frequency (VLF) transmitter, which continuously transmits a warning signal to alert personnel in the vicinity of the presence of the vehicle while it is moving. To this end, the vehicle is provided with an omni-directional magnetic loop antenna 18, arranged to transmit the warning signal around the vehicle in all directions. It will be appreciated that, in some applications, it may be preferable to have a directional antenna, or multiple antennas which are selected according to the direction of travel of the vehicle, for example.
The vehicle's transmitter arrangement is shown in Figure 2, and includes the transmit antenna 18, a VLF transmitter 20, and a transmission power control circuit 22 which is arranged to receive a speed signal from a speed transducer in the vehicle. The power control circuit is arranged to adjust the output power of the transmitter 20 according to the value of the signal received from the speed transducer, so that the transmitter output power is increased as the speed of the vehicle increases.
In the case of omni-directional transmission, the intensity of the transmitted warning signal falls off with the cube of the distance from the antenna 18, and the power control circuit 22 can be calibrated accordingly, so that the strength of the warning signal is related to the braking distance corresponding to a given vehicle speed. The power control circuit can be arranged to increase the output power of the transmitter in relation to the input speed signal, or in a stepwise manner with one or more speed threshold settings, or in another desired manner to ensure an adequate warming zone for speed variation. In Figure 1 , the concentric circles marked "5km/h", "10km/h", "15km/h" and "20km/h" indicate schematically the effective range of transmission of the warning signal from the vehicle 10 as the speed of the vehicle increases and the output power of the warning signal transmission is increased accordingly. It will be appreciated that Figure 1 is not drawn to scale in this regard.
This is an important feature compared with prior art systems. The risk posed by a moving vehicle is related to the speed of the vehicle. Known systems provide the same effective warning or detection zone irrespective of vehicle speed. In order to have a large enough detection zone to provide sufficient warning when the vehicle is traveling at its maximum speed, a sufficiently strong signal is required, which will result in unnecessary alarms at low speed.
Particularly in the case of an underground mine working with a number of possible obstructions, and also particularly in the case of an omnidirectional transmission, it is desirable to use a relatively low frequency ^ for the warning signal. For example, is preferably less than 200 kHz. In prior art systems using much higher frequencies, the propagation of radio waves becomes highly dependent on the environment. In an underground mine working, for example, the presence of steel structures, cables, pipes and the shape and size of the working itself, has a dramatic effect on the coverage obtained by such a system, with the result that a warning zone within which signals can successfully be received has an unpredictable size and shape. When UHF signals are used, reflections, multipath propagation and attenuation by stray objects exacerbate the situation. The result is false alarms or reduced system performance. Referring now to Figure 3, the components of a portable receiver which can be worn or carried by personnel is shown. The receiver comprises a miniature loop antenna 24 and an RF receiver circuit 26. The receiver circuit has an output which can operate a relay 28 with its contacts arranged in series with a battery 31 and a lamp 32. The relay has normally open contacts, which are held closed in normal operation by an output signal from the receiver circuit 26, in a fail safe arrangement.
In the present example, the lamp 32 is conveniently a miner's cap lamp and the battery 31 is the associated cap lamp battery carried by a miner. Thus, on receipt of the warning signal from the vehicle 10, the output of the receiver 26 causes the contacts of the relay 28 to open, typically repetitively at a predetermined rate and for a predetermined period, causing the lamp 32 to flash and thus alerting the wearer of the lamp to the proximity of the vehicle 10. Instead or in addition, a buzzer, sounder or another indicator can be provided to ensure that the user of the portable receiver unit is alerted to the presence of the vehicle 10.
It will be appreciated that the faster the vehicle 10 is travelling, the sooner the personnel 14, 15 and 16 in Figure 1 will be alerted to its proximity, due to the corresponding increase in the transmission power of the warning signal from the vehicle. Effectively, a warning zone is created around the vehicle 10 by the warning signal, with the extent of the warning zone being related to the power of the warning signal. In an alternative arrangement, the warning signal could have a constant power, but another characteristic of the signal such as its continuous modulation frequency could be altered in accordance with the measured speed of the vehicle. As another alternative, the warning signal can be modulated with various data. For example, the data could indicate the nature of the vehicle broadcasting the warning signal, its speed, or could comprise information about the nature of the risk posed by the approaching vehicle.
In Figure 1 a situation is depicted in which the personnel 14 and 15 have been warned (assuming that the vehicle is traveling at 20km/h or more), while the individual 16, who is further away from the vehicle than the others, will not yet have received the warning signal.
In a refinement of the basic system described above, a portable transmitter is provided together with the* portable receiver worn or used by individual personnel, and a corresponding receiver is located in the vehicle 10, in association with its transmitter.
Referring again to Figure 3, a portable transmitter 30 is shown which has an antenna 36. An optional ID encoder circuit 35 is connected to the transmitter 30 and is arranged to modulate or encode the output of the transmitter 30 with data corresponding to an identity code allocated to the user of the device. The transmitter is connected to the battery 31 or another power supply, and a push button 34 is arranged to power the transmitter and the associated ID encoder 35 when it is depressed.
The purpose of the portable transmitter is to permit the user thereof to transmit a response signal to the vehicle 10 when the user has become aware of it. For example, if the user is in a location which makes it difficult to move rapidly out of the path of the approaching vehicle, or is occupied with a task which cannot readily be interrupted, the user may operate the push button 34 to send a response signal to the operator of the vehicle, warning the operator of his/her presence. The response signal is preferably transmitted at a frequency f2, which is substantially higher than the frequency fi.
In the vehicle 10, a receiver 36 has an antenna 46 and is connected to an alarm circuit 38 with an associated vehicle hooter 40, headlights 42 and a relay 44 arranged to control the vehicle ignition. The receiver 36 output is also connected to a data logger 39, which provides event logging including the time and vehicle speed when signals are received by the receiver 36. This provides a record of events that can be used in case of an accident. For example, if the operator of the vehicle ignores response signals, leading to an accident, this can be established from the data logger record. If a signal is received from the portable transmitter, the hooter 40 and/or the headlight 42 are operated, alerting the driver of the vehicle to the presence of a person whom the driver of the vehicle must take care to avoid. This serves at the same time to confirm to the person transmitting the signal to the vehicle that the signal has been received. However, it can be noted that in most cases, where personnel are able to move out the path of the vehicle 10 without difficulty, there is no need for them to transmit a response signal to the vehicle, so that the driver is not distracted or annoyed by a large number of warning signals. Effectively, therefore, the method and system of the invention transfer the primary responsibility to avoid collisions between a vehicle and individual personnel to the individuals themselves, and assist them in this regard by providing a warning of the approach of a vehicle.
In the event that an individual is unable to move out of the path of the vehicle, an emergency stop signal can be transmitted to the vehicle by pressing the push button 34 a second time. The alarm circuit 38 detects that the same transmitter 30 has transmitted a further signal, and responds to this emergency stop signal by operating the relay 44, the contacts of which can be arranged in series with the vehicle ignition, for example, thus bringing the vehicle to a halt. Alternatively, if the driver does not respond to the first response signal within three to four seconds, the vehicle will be stopped automatically. By varying the strength of the warning signal transmitted by the vehicle with the speed of the vehicle, and calibrating the transmitter so that the effective size of the warning zone corresponds to a practical braking distance for the vehicle at a given speed, the efficacy of the system is enhanced.
It will be appreciated that a number of modifications and variations of the above described system are possible, but the essence of the system is that mobile equipment such as a vehicle transmits a primary warning signal to personnel in the vicinity, who in most instances can take evasive action if required. Essentially, the responsibility to take evasive action is transferred to the personnel concerned. If necessary, but only as required, personnel can respond to the primary warning signal with a response signal, alerting the driver or operator of the mobile equipment to their presence and allowing the driver or operator to stop the vehicle or take appropriate avoidance measures. Additionally, an emergency stop feature is provided, allowing personnel who feel threatened by the approach of the mobile equipment to cause it to stop immediately.
As described above, the warning signal is preferably a VLF signal. As the VLF magnetic field penetrates easily through rock, a reliable warning of miners who have obstacles between them and the vehicle, such as the individual 15 in Figure 1 who is around a corner from the vehicle 10, is possible.

Claims

1. A method of warning personnel of the presence of mobile equipment, the method comprising:
transmitting a warning signal from mobile equipment, the warning signal having a characteristic which varies according to the speed of movement of the mobile equipment;
receiving, via a receiver associated with one or more personnel, the warning signal when the mobile equipment approaches said personnel; and
providing an indication to said personnel of the approach of the mobile equipment.
2. A method according to claim 1 comprising transmitting the warning signal from a vehicle.
3. A method according to claim 2 wherein the strength of the warning signal and accordingly the extent of a corresponding warning zone is increased as the speed of the vehicle increases.
4. A method according to claim 3 wherein the strength of the warning signal is related to a braking distance of the vehicle corresponding to the vehicle speed.
5. A method according to any one of claims 1 to 4 wherein the indication which is provided to said personnel is a visible or audible indication.
6. A method according to claim 5 wherein the receiver is arranged to control a light used by said personnel and/or to operate a buzzer or the like.
7. A method according to any one of claims 1 to 6 including transmitting a response signal from said personnel to the approaching mobile equipment, receiving the response signal at the mobile equipment, and providing an indication to an operator of the mobile equipment of the proximity of said personnel.
8. A method according to claim 7 including transmitting a control signal from said personnel to the approaching mobile equipment, the mobile equipment being responsive to the control signal to modify its movement.
9. A method according to claim 8 wherein the control signal is an emergency stop signal to which the mobile equipment responds by stopping.
10. A system for warning personnel of the presence of mobile equipment, the system comprising:
a first transmitter associated with mobile equipment and arranged to transmit a warning signal, the warning signal having a characteristic which varies according to the speed of movement of the mobile equipment;
at least one first receiver which can be associated with one or more personnel, said at least one first receiver being operable to receive the warning signal from the first transmitter when the mobile equipment approaches said personnel and to provide an output signal indicative thereof; and an indicator responsive to the output signal of said at least one first receiver to provide an indication to said personnel of the proximity of the mobile equipment.
11. A system according to claim 10 wherein the mobile equipment is a vehicle, and the first transmitter has an associated antenna mounted on the vehicle.
12. A system according to claim 10 or claim 11 including a control circuit responsive to an input signal representative of the speed of the vehicle, the control circuit being arranged to control the operation of the first transmitter to vary a characteristic of a signal transmitted by the first transmitter according to the speed of the vehicle.
13. A system according to claim 12 wherein the control circuit is arranged to adjust the power of the signal transmitted by the first transmitter so that the power of the signal increases as the speed of the vehicle increases, so that the extent of a corresponding warning zone is increased accordingly, the power of the signal being related to a braking distance of the vehicle corresponding to the vehicle speed.
14. A system according to any one of claims 10 to 13 including a second transmitter associated with said one or more personnel, the second transmitter being arranged to transmit a response signal from said personnel to approaching mobile equipment, the mobile equipment having a second receiver arranged to receive the response signal, and an indicator arranged to warn an operator of the mobile equipment of the presence of said personnel.
15. A system according to claim 14 wherein the second transmitter is operable to transmit a control signal, the mobile equipment having a control circuit associated with the second receiver which is responsive to the control signal to modify the movement of the mobile equipment.
16. A system according to claim 15 wherein the control circuit is responsive to the control signal to stop the movement of the mobile equipment.
PCT/IB2004/001088 2003-04-08 2004-04-07 Collision avoidance method and system WO2004090830A1 (en)

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US10769955B2 (en) 2007-10-25 2020-09-08 Strata Safety Products, Llc Proximity detection system and method and collision avoidance system and method using proximity detection
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WO2017109695A1 (en) 2015-12-22 2017-06-29 Swisstip Sa Antenna and anticollision detecting system comprising this antenna
CN109308817A (en) * 2018-09-03 2019-02-05 山东大学 Position is shared in construction tunnel and traffic safety hidden danger early warning system and method
CN109882243A (en) * 2019-03-28 2019-06-14 长安大学 A kind of underground rubber-tired cart speed runaway barrier system and stop method
CN109882243B (en) * 2019-03-28 2024-02-13 长安大学 Underground rubber-tyred vehicle speed out-of-control blocking net system and blocking method
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