GB2554529A

GB2554529A - A Movable traffic signal or movable pedestrian signal system

Info

Publication number: GB2554529A
Application number: GB1712521.2A
Authority: GB
Inventors: John Heaton Stephen; Michael Hutchinson Peter
Original assignee: PIKE SIGNALS Ltd
Current assignee: PIKE SIGNALS Ltd
Priority date: 2016-08-05
Filing date: 2017-08-03
Publication date: 2018-04-04
Anticipated expiration: 2037-08-03
Also published as: GB2554529B; GB201712521D0

Abstract

A movable traffic signal apparatus for use in controlling the movement of traffic or people on a temporary basis comprises: at least one movable traffic signal 100, 200 comprising an illuminated sign 5; a receiver for receiving control signals on one of two different radio frequency bands; a drive circuit arranged to drive the lights of the illuminated sign according to the received control signals; and a transmitter arranged to transmit control signals; and further including switching means enabling the apparatus to be configured to transmit and to receive control signals in either the first radio frequency band or the second radio frequency band. The two bands allows greater flexibility of installation when the apparatus is to be used in environments where there may be lots of interference or noise.

Description

(71) Applicant(s):

Pike Signals Ltd

Units 7, 9 & 11 Phoenix Business Park, Avenue Road, Aston, BIRMINGHAM, West Midlands, B7 4NU,

United Kingdom (51) INT CL:

G08G 1/0955 (2006.01) (56) Documents Cited:

JP 2012174216 A US 20150061896 A1 (58) Field of Search:

INT CL G08G

G08G1/07 (2006.01)

JP 2010157125 A US 20120216436 A1

Other: WPI, EPODOC, Patent Fulltext, Internet (72) Inventor(s):

Stephen John Heaton Peter Michael Hutchinson (74) Agent and/or Address for Service:

Barker Brettell LLP

100 Hagley Road, Edgbaston, BIRMINGHAM, B16 8QQ, United Kingdom (54) Title of the Invention: A Movable traffic signal or movable pedestrian signal system Abstract Title: Moveable traffic signal system (57) A movable traffic signal apparatus for use in controlling the movement of traffic or people on a temporary basis comprises: at least one movable traffic signal 100, 200 comprising an illuminated sign 5; a receiver for receiving control signals on one of two different radio frequency bands; a drive circuit arranged to drive the lights of the illuminated sign according to the received control signals; and a transmitter arranged to transmit control signals; and further including switching means enabling the apparatus to be configured to transmit and to receive control signals in either the first radio frequency band or the second radio frequency band. The two bands allows greater flexibility of installation when the apparatus is to be used in environments where there may be lots of interference or noise.

At least one drawing originally filed was informal and the print reproduced here is taken from a later filed formal copy.

1/3

200

A

2/3

11 17

Fi

3/3

11 17

Figure 3

A MOVABLE TRAFFIC SIGNAL OR MOVABLE PEDESTRIAN SIGNAL SYSTEM

This invention relates to movable signal systems such as traffic lights and pedestrian signal systems, in particular but not exclusively non-permanent radio controlled traffic lights or other radio controlled roadside signals.

Permanent traffic signals, by which we mean those that are secured in place, typically including a support mast that is permanently bolted into place or concreted into the ground, and movable traffic and pedestrian signals are well known. Movable signals can generally be divided into two types: portable signals which generally have wheels or rollers allowing them to be moved manually and temporary signals which generally have a heavy supporting base that can be lifted and moved using a forklift truck or pallet handler. In general, the term movable refers to a light that can be readily moved between different locations and reused.

The most commonly used traffic signals are traffic lights, which control the flow of traffic along a section of highway or across a junction. The signal is typically a set of three coloured lights: red, amber and green, used to control the flow of traffic along a highway. Pedestrian signals are commonly used to control the flow of people, mostly pedestrians but sometimes also cyclists, across a highway. They typically comprise an illuminated sign representing a person standing still and an illuminated sign representing a person walking. The person standing still is usually illuminated with a red light, and walking a green light. Other images are known, depending on the traffic rules for the location in which they are installed. A combined traffic and pedestrian signal will include both types of sign. These signs are held at a convenient location above the highway on a signal head.

Movable traffic signals and movable pedestrian signals can be easily moved around and are therefore suitable for being temporarily placed at junctions or sections of road where road works are being carried out. In this specification the term “junction” refers to any arrangement where two or more lights control the flow of traffic. For instance, it may be a junction between two roads, such as a cross roads or T-junction, or a junction between the two ends of a stretch of flow controlled highway, for instance a length of road that can only carry traffic in one direction at any time as is typical during road works.

Where two are more traffic signals are provided, it is important that they are able to communicate which each other to ensure that the relative phasing of the signals is correct. The lights may be radio controlled, allowing a master signal to “talk” to other slave signals in a group to co-ordinate the phasing of the signals, and in some cases to allow the slave signals to “talk back” to the master signal. Depending on the complexity of the road or junction and the scale of the road works, up to 34 portable signals have been known to be used. Radio control is in most cases an essential feature, as it may be impossible to connect the signals by hard wired connection, and even when that would be possible it is greatly more convenient to connect wirelessly.

Where the lights are radio controlled, there are times when the lights may not be able to communicate with each other due to interference from nearby sources of radio signals, such as automatic door openers, emergency vehicles, public utility equipment or other nearby traffic signals. This is especially problematic in highly built up urban areas. An object of the present invention is to ameliorate the problems that may arise when operating radio controlled traffic signals in urban areas.

According to a first aspect this invention provides a movable traffic signal apparatus for use in controlling the movement of traffic or people on a temporary basis, the apparatus comprising:

at least one movable traffic signal comprising an illuminated sign including one or more lights, a receiver for receiving control signals on one of two different radio frequency bands, a drive circuit arranged in use to drive the lights of the illuminated sign according to the received control signals, and a transmitter arranged to transmit control signals, and further including switching means enabling the apparatus to be configured to transmit and to receive control signals in either the first radio frequency band or the second radio frequency band.

By different radio frequency bands we mean different open spectrum radio frequency bands as defined by the International telecommunication union (ITU).

The ability to transmit control signals in one of two frequency bands, and to receive control signals on one of the two frequency bands, provides great flexibility of installation when the control signals are to be used in environments where there may be a lot of radio frequency noise which may interfere with the received signals.

The switching means may be adapted to switch the receiver to the same frequency band that the transmitter transmits signals on, so that when transmitting on the first band the apparatus listens on the same first band, and when transmitting on the second band signals are received on the second band.

The transmitter and receiver may be further configured within at least one of those bands to transmit signals on one of a plurality of channels. Each of the two bands may be divided into two or more channels, and the switching means may enable the operator to choose which band and channel control signals are to be transmitted on.

The apparatus may comprise a radio circuit board which is provided with a first transmitter and receiver chipset, and a second transmitter and receiver chipset, each receiver and transmitter chipset corresponding to one of the two frequency bands. The switching means may in use select between the two chipsets.

The two chipsets may share a common frequency oscillator, or they may each be provided with their own oscillators.

The two radio frequency bands may fall within the ultrahigh frequency (UHF) bands.

The frequency bands may comprise a first set of frequencies in the approved band of 869-960MEiz, for example channels centred on a frequency of approximately 869MHz, and a second set of frequencies in the approved band of 457-464MHz, for example channels centred on a frequency of approximately 458MHz.

These two bands are especially beneficial as they correspond generally to different types of devices- the 869MHz being widely used for cellular communications and therefore previously the only band used by radio controlled traffic signals. The applicant has appreciated that switching to the 458MHz band generally associated with utilities such as electricity and gas, where appropriate, greatly increases the chances of finding a low noise channel for use by the apparatus.

Within each band the channels may correspond, amongst others, to any of the following frequencies:

869.475MHz and 869.565MHz within the 869Mhz band, and 458.525MHz, 458.550MHz, 458.575MHz, and 458.600MHz within the 458MHz frequency band.

Of course, other frequency bands could be used.

The movable traffic signal may comprise a base unit, a support mast that may be of fixed length or telescopic, and the signal head may be supported by the support mast.

The movable traffic signal with the configurable transmitter/receiver may be configured as a master traffic signal and the apparatus may additionally comprise at least one slave movable traffic signal. This may be located remote from the master signal. For instance, the master and slave may be located in use on opposing sides of a junction across which traffic flow is to be controlled.

The apparatus may include more than one traffic signals configured as a slave. A single master traffic signal may transmit control signals that set the timing of two or more, perhaps up to 32, or 64, or a higher number of slave traffic signals.

Each of the slave traffic signals and the master traffic signals may be identical and a configuration means may be provided within each apparatus enabling it to be placed into a slave or a master configurations. This configuration means may be part of the switch means, and may comprise a switch or button or lever or other user operable input device.

Alternatively, the slave traffic signal may not include a transmitter and may only be arranged to receive signals on one of the two radio frequency bands as configured by a user with the switching means. These apparatus may define slave units and may therefore comprise:

an illuminated sign including one or more lights, a receiver for receiving control signals on one of two different radio frequency bands, a drive circuit arranged in use to drive the lights of the illuminated sign according to the received control signals, and further including switching means enabling the apparatus to be configured to receive control signals in either the first radio frequency band or the second radio frequency band.

The receiver and transmitter of the traffic signal may be housed within a base unit. This base unit may support a mast that in turn support a signal head that supports the lights of the illuminated sign. Typically this mast may comprise a pole of between lm and 3 m in length, which may be telescopic.

The illuminated sign of each traffic signal may comprise two or more lights. There may be a red light, an amber light and a green light arranged vertically in a row to form a traffic light signal head or a repeater unit.

The lights may be circular in shape for a traffic light, and may be red and green respectively. The illuminated sign may include a third light, which may be amber.

The illuminated sign of at least one traffic sign may comprise a pedestrian sign, with a green light that illuminates a sign that it is safe to cross and a red light that illuminates a sign that it is not safe to cross.

The illuminated sign may form a nearside signal, to be attached to a support at the side of the junction.

The lights of the illuminated sign may comprise incandescent bulbs or light emitting diodes or a mixture of those two types of light. The lights may comprise three different colours: red, green and amber; or two different colours: red and green.

The movable traffic signal may include a battery that provides power to the lights. A control unit may be located in the base unit. This may incorporate the radio board carrying the receiver and transmitter.

By movable we may mean that the traffic signals are self-contained and easy to move about, for instance with wheels or rollers to form a portable device or with a base designed for lifting using a forklift or pallet handler in the case of a temporary device.

The drive circuit of each traffic sign may include a processor which receives the control signals received by the receiver and from those control signals extracts or derives, for each light of the sign, a respective drive signal. The drive signal for each light may comprise a non-zero voltage or current when the light is to be illuminated and a zero voltage or current when the light is not to be illuminated, thereby encoding timing information for the lights. The or each drive signal may be modulated with the required timing for the lights, the information required to set the timing being defined by, or derivable from, the information carried within the control signals.

The drive circuit may receive a phasing signal for each light of the sign from the receiver. These signals may be encoded in the control signal received by the receiver.

The switching means that enables an operator to manually select the frequency band that is to be used by the receiver and the transmitter.

The switching means may comprise a control panel through which the operator can program the apparatus to configure the receiver and the transmitter.

The switching means could comprise a switch or button, either a physical switch or button or a soft switch or button implemented in software. The switch means may comprise a control panel which may be accessible from outside of the housing, and which may be lockable to prevent unauthorised changes being made. The switch means may be lockable by providing a lockable cover that can be placed on the switch means.

The ability to manually select the frequency band and channel allows the operator to easily reconfigure the system if the lights are not performing correctly which may be due to interference. Moving to a different, less noisy, frequency band, allows the apparatus to be used in noisy urban environments.

The apparatus may default to a set one of the two frequency bands when first powered up, regardless of which band was selected before power up. This allows the operator to simply install multiple apparatus at a junction to be controlled knowing they are all initially on the same one frequency band. If a change is needed they may then manually change each apparatus. Alternatively they could power up on the same frequency that was last used, which means that provided that a set of lights are not mixed up with other lights they always start on the same frequency band. Again this simplifies the set up process.

Alternatively, the apparatus may automatically select a frequency band according to the signal quality of the reception of signals on that band by transmitting on at least two different frequency bands in sequence and selecting the one with the best quality of signal reception. The apparatus may include a quality testing means that determines the noise present on a given frequency band and makes the selection in response to the determined noise levels.

Alternatively, the apparatus may be configured to transmit a frequency selection signal indicative of a selected frequency upon the operator configuring the apparatus to a change of frequency, and may be configured to respond to a received frequency selection signal to automatically change to the frequency indicated by the selection signal. This allows the operator to change the frequency band for all apparatus from one apparatus.

The apparatus may further include an input port which permits connection of the apparatus by a hard wired connection to a further movable traffic signal apparatus at a junction to receive control signals. It may further include an output port which permits connection of the apparatus by a hard wired connection to a further movable traffic signal apparatus at a junction to transmit control signals.

Providing a hard wired option allows the control signals to be used in very noisy environments where neither of the two frequency bands is sufficiently free of noise to allow reliable operation of the apparatus.

According to a second aspect the invention provides a traffic signal system comprising at least two movable traffic signal apparatus according to the first aspect, in which the receiver of a first one of the apparatus is configured to the same frequency band as the transmitter of a second one of the apparatus such that the first apparatus can receive control signals from the second apparatus.

The first apparatus may include a transmitter for transmitting additional information back to the second apparatus, which in turn uses the additional information to modify the control signals that are to be sent to the first apparatus.

For example, the additional information may comprise traffic flow or presence information captured by a camera or radar apparatus.

The control signals transmitted by the second apparatus may determine when the lights go red or green and this may be modified by the additional information. For instance, the controller may delay turning a light from red to green or vice versa some time after the relevant bit of a databyte control signal requests a change from red to green if it is not considered safe to change.

The second apparatus may generate the control signals or may receive the signals from a remote controller. The second apparatus may transmit control signals to more than one first apparatus, and as such may form a master apparatus with the further apparatus acting as slaves.

There will now be described by way of example only, one of a portable temporary light system suitable for use in controlling a junction in a noisy environment, with reference to the accompanying drawings of which:

Figure 1 shows an embodiment of a portable traffic signal system of the present invention set up to protect a length of highway under repair;

Figure 2 is a view from the front of a portable traffic signal of the system of Figure 1; and

Figure 3 is a block diagram showing the key functional parts of an embodiment of a traffic signal apparatus of the system of Figure 1.

Figure 1 shows a portable traffic light system comprising a set of movable traffic light apparatus that are installed at a section of highway that is being repaired and reduced to one lane. In this example there are two traffic lights 100,200, each controlling the flow of traffic for a respective directions across the repair section. The phasing of the lights is synchronised so that at any time traffic can flow in only one direction along the highway, from A to B or B to A. To achieve this phasing, the traffic lights each respond to control signals supplied from one of the lights that acts as a master controller (the other acting as a slave). The control signals are transmitted wirelessly between the signals and received using wireless receivers fitted to each signal.

The control signals may encode directly the timing for each light, for instance using pulse width modulation, or may be encoded in such a way that the timing for each light can be decoded from the control signals to produce a set of drive signals for the lights. The control signals will typically be digital signals that encode one or more of the following items of information:

Message type, Message length, Master traffic signal ID, Slave traffic signal ID, Run number, CRC, Terminator, Phase number, Battery voltage, Max Red time and Aspect data.

The skilled person in the art of traffic signals will appreciate how this signals can be encoded and used to control the operation of the lights.

Both of the traffic signals in this example are identical in construction but differ in configuration to cause one to function as the master and the other as the slave. An example of the traffic signals are shown in more detail in Figure 2.

As shown in Figure 2 each movable traffic signal 100,200 comprises a base unit 1 that support a signal head 2 on a support pole 3. Wheels 4 allow the unit to be easily moved around the worksite. The lights 5 of the signal head, in this case a red, amber and green light as is standard for a traffic light, are controlled by drive signals supplied by an electronic circuit 6 contained within the base of the traffic light. The circuit for the slave receives control signals that are receiver from the master signal, or in the case of the master signal the control signals may be generated internally by the electronic circuit. The electronic circuit is powered by a battery 7, which in the example shown is located inside the base. Power could be supplied from an external source in other embodiments.

The electronic circuit 6 is shown schematically in Figure 3. The main components are a radio board 8, indicated by dashed line, a micro controller 9 and a line drive circuit which in this embodiment is in the form of an RS485 interface 10. The radio board 8 and interface 10 enable the traffic signal to send and receive control signals by radio frequency and hard wired link respectively to the other traffic light of the pair, or to further lights in a more complex junction control arrangement. The micro controller processes the transmitted and receiver control signals as appropriate to produce a set of drives signals- one per light- which are modulated with the phasing for the lights.

The radio board 8 comprises a pair of transceiver chipsets- each defining a respective receiver and a transmitter of matched frequency. One chipset 13 is tuned to a frequency band of 458Mhz and the other chipset 14 is tuned to a frequency band of 869Mhz. The two chipsets share an oscillator 15. The input/output of each chipset is connected to a respective antenna 16,17.

An EEPROM 9 with memory stores program instructions for the microcontroller, enabling control signals to be generated and then sent to the radio board for transmission where the traffic signal is acting as master signal.

The circuit also includes a front end user interface 12 which defines a user operable switch means. This allows a user to alter the function of the signal, to set it to operate as a master or a slave, and to set the frequency and channel across which radio frequency control signals are transmitted. The switch means may comprise a control panel, with soft buttons that allow the user to select the frequency band and channel

In use, the user sets the transmit frequency band of the master signal to the same as the slave signal using the switch means. This may be either the first frequency or the second frequency band. A channel is the chosen from within the chosen frequency band. The two signals then exchange information over that channel. The user may select the band and channel which minimises any interference.

Claims

1. A movable traffic signal apparatus for use in controlling the movement of traffic or people on a temporary basis, the apparatus comprising:

2. A movable traffic signal apparatus according to claim 1 in which the switching means is adapted to switch the receiver to the same frequency band that the transmitter transmits signals on, so that when transmitting on the first band the apparatus listens on the same first band, and when transmitting on the second band signals are received on the second band.

3. A movable traffic signal apparatus according to claim 1 or claim 2 in which the transmitter and receiver are further configured within at least one of those bands to transmit signals on one of a plurality of channels.

4. A movable traffic signal apparatus according to any preceding claim which comprises a radio circuit board which is provided with a first transmitter and receiver chipset, and a second transmitter and receiver chipset, each receiver and transmitter chipset corresponding to one of the two frequency bands.

5. A movable traffic signal apparatus according to claim 4 in which the two chipsets share a common frequency oscillator.

6. A movable traffic signal apparatus according to any preceding claim in which the frequency bands comprise a first set of frequencies in the approved band of 869960MHz, and a second set of frequencies in the approved band of 457-464MHz.

7. A movable traffic signal apparatus according to any preceding claim which is configured as a master traffic signal and in which the apparatus additionally comprises at least one slave movable traffic signal.

5

8. A movable traffic signal apparatus according to claim 7 in which each slave movable traffic signal comprises:

an illuminated sign including one or more lights, a receiver for receiving control signals on one of two different radio frequency bands, a drive circuit arranged in use to drive the lights of the illuminated sign according to the received control signals,

10 and further including switching means enabling the apparatus to be configured to receive control signals in either the first radio frequency band or the second radio frequency band.

9. A traffic signal system comprising at least two movable traffic signal apparatus

15 according to any preceding claim, in which the receiver of a first one of the apparatus is configured to the same frequency band as the transmitter of a second one of the apparatus such that the first apparatus can receive control signals from the second apparatus.

Intellectual

Property

Office

Application No: GB1712521.2 Examiner: Anna Rice