WO2010064963A1

WO2010064963A1 - A lane change assistance system

Info

Publication number: WO2010064963A1
Application number: PCT/SE2008/000684
Authority: WO
Inventors: Lena Larsson
Original assignee: Volvo Lastvagnar Ab
Priority date: 2008-12-05
Filing date: 2008-12-05
Publication date: 2010-06-10

Abstract

The invention discloses a lane change assistance system (20) for a vehicle (10, 10'), and comprises at least one sensor unit (18, 19, 20, 21, 22, 23, 24) for arrangement on the vehicle (10, 10') and a control unit (29) adapted for installation in the vehicle (10, 10') and arranged for the control of and communication with the at least one sensor unit (18, 19, 20, 21, 22, 23, 24). The at least one sensor unit comprises an active sensor which is adapted to transmit signals and to receive reflections of the transmitted signals in order to detect objects within a first predetermined distance (R1) in a substantially lateral direction from the vehicle, with the sensor of the at least one sensor unit being activated and/or deactivated by the control unit (29) when certain predetermined criteria are fulfilled. The system also comprises indication means connected to the control unit for indicating the detection of objects by the system.

Description

A LANE CHANGE ASSISTANCE SYSTEM

TECHNICAL FIELD

The present invention discloses an improved lane change assistance system for a vehicle, in particular for a vehicle such as a heavy vehicle, e.g. a cargo vehicle with or without a trailer attached.

BACKGROUND

When a heavy vehicle such as, for example, a truck, overtakes another vehicle, it can sometimes be difficult for the driver of the overtaking vehicle to know when the it is possible to return to his previous lane again, i.e. when the overtaken vehicle has been passed with such a distance that the overtaking vehicle can turn into the lane in which the overtaken vehicle is driving.

Traditionally, this problem has been solved by means of the driver of the overtaken vehicle signalling with his headlights, in order to indicate to the driver of the overtaking vehicle that it is now safe to return to the lane of the overtaken vehicle.

However, this solution to the problem relies on the driver of the overtaken vehicle, and is thus not as reliable as might be wished for.

The same problem can of course arise when a driver simply wishes to change lanes without having overtaken another vehicle, i.e. in this situation it will also be necessary for the driver to ascertain if there are other vehicles adjacent to him in the lane which the driver wishes to change into.

SUMMARY Thus, as explained above, there is a need for a solution by means of which a driver who is about to perform a lane change can ascertain if it is safe to change lanes or not, i.e. if there are other vehicles adjacent to him in the lane which the driver wishes to change into.

This need is addressed by the present invention in that it discloses a lane change assistance system for a vehicle, which comprises at least one sensor unit for arrangement on the vehicle. The system also comprises a control unit which is adapted for installation in the vehicle, and which is arranged for the control of and communication with the at least one sensor unit.

In the system of the invention, the at least one sensor unit comprises an active sensor, i.e. a sensor which is adapted to transmit signals and to receive reflections of the transmitted signals in order to detect objects within a first predetermined distance in a substantially lateral direction from the vehicle.

The sensor of the at least one sensor unit is activated and/or deactivated by the control unit when certain predetermined criteria are fulfilled, and the system also comprises indication means which are connected to the control unit, for indicating the detection of other vehicles by the system.

The invention's feature of being able to detect objects within a first predetermined distance in a substantially lateral direction from the vehicle is achieved by means of the use of active sensors, and makes it possible for a driver to be alerted to the presence of objects such as other vehicles in a lane which is immediately adjacent to the lane the driver is in at the moment, whilst not letting objects, e.g. vehicles, in more distant lanes cause detections.

In one embodiment, the system of the invention also comprises means for wireless communication between the control unit and the sensor unit, in order for the sensor unit to receive control signals and to transmit the detection or absence of detection of objects to the control unit. Also, in one embodiment, the system of the invention comprises two or more sensor units with active sensors, with at least one of the active sensors also being arranged to detect the presence of objects which are within a second predetermined distance within a predetermined oblique angular range from the vehicle.

In one embodiment of the system of the invention, each sensor unit is adapted to communicate wirelessly with the control unit individually.

In another embodiment of the system of the invention, at least one sensor unit is adapted to communicate with at least one other sensor unit wirelessly, and at least one sensor unit is adapted to act as a "relay station" between the control unit and the other sensor unit or units, i.e. the "relay station" is arranged to transmit communication between the other sensor units and the control unit.

Suitably but not necessarily, the control unit of the system is arranged to be connected to a turn indicator control in the vehicle, so that the activation command for the sensors is performed from the turn indicator, by means of which one or more sensors arranged for detection in a certain direction can be activated.

Also, in one embodiment of the invention, the control unit comprises means by which an operator of the system can indicate a certain speed range of the vehicle within which the sensors of the sensor units will not be activated.

In addition, in one embodiment, the control unit comprises means by which an operator of the system can adjust said oblique angular range, in order to correspond to a varied effective length of the vehicle. The control unit is also, in one embodiment, equipped with means for letting an operator of the system adjust the predetermined lateral sensing distance.

These and other embodiments and advantages of the invention will be described in more detail in the following.

The invention also discloses a vehicle fitted with the system in any of the embodiments described above and in the following.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described in more detail in the following, with reference to the appended drawings, in which

Fig 1 shows a top view of a problem to be solved by the present invention, and Fig 2 shows a first embodiment of the invention, and

Figs 3-5 show top views of different embodiments of the invention, and

Fig 6 shows another embodiment of the invention, and

Fig 7 shows a detail of the invention, and

Fig 8 shows a display of one embodiment of the invention, and Fig 9 shows a side view of a vehicle fitted with one embodiment of the invention.

DETAILED DESCRIPTION

In the following, the invention will be described using heavy vehicles as an example of vehicles in which the invention can be applied. It should however be pointed out that this is merely in order to clarify the description of the invention, and should in no way be used to limit the invention, which may be applied to more or less any kind of vehicle, such as buses, cars etc, including vehicle combinations such as cars or trucks which tow trailers or caravans.

Fig 1 shows a schematic top view of a problem to be addressed by the present invention. As shown in fig 1 , a first vehicle 10 in an outer lane 11 is in the process of overtaking a second vehicle 12 in an inner lane 13. The overtaking has not yet been completed, as shown by means of an indicated distance ΔR. Thus, if the driver of the vehicle 10 were to attempt to turn into the inner lane 13, an accident would occur. In fact, in order for the vehicle 10 to be able to turn into the inner lane 13 in a safe manner, the longitudinal distance between the vehicles needs to be not only ΔR, but needs to exceed the distance ΔR by a certain margin. In addition, the inner lane needs to be clear of other vehicles in front of the vehicle 12 by a distance which at the very least corresponds to the length of the vehicle 10.

Naturally, the same problem may arise when changing lanes without having overtaken another vehicle: in such a situation, it will also be necessary to ascertain if there are other vehicles adjacent to the own vehicle in the lane in which it is desired to change into, whether it is to the right or to the left of the own vehicle.

The present invention lets the driver of the vehicle 10, i.e. the vehicle which is changing lanes, ascertain in a safe manner if these conditions are met, and if it thus is safe to turn into the inner lane 13.

A schematic overview of a system 20 of the present invention is shown in fig 2, which also shows a vehicle, in order to exemplify how the system is used, in this case a heavy vehicle 10 which tows a trailer 10'.

A system 20 of the invention comprises at least one sensor unit, although the example of fig 2 shows two sensor units 21 , 22. The number of sensor units in a system of the invention can be varied, so that the system comprises one or more sensor units. As indicated in fig 2, the sensor units of the system are intended to be arranged on the vehicle 10, 10', primarily on the sides of the vehicle, as shown in fig 2, although both the rear and the front of the vehicle, as well as the top of the vehicle are also possible positions for the sensor units of the invention. In addition to the sensor units 21 , 22, the system 20 also comprises a control unit 29, which is adapted for installation in the cabin of the vehicle 10, so that it may be easily accessed by the driver.

The sensor unit or units of the system 20 comprise a sensor which is an active sensor, i.e. a sensor which transmits one or more signals, and performs detection using reflections of the transmitted signal or signals. Naturally, this can also be divided, so that one or more sensor units transmit signals, and other sensor units use reflections from those signals in order to carry out detection. The signals emitted by the sensors can for example either be radio signals, i.e. so that the sensors are radar sensors, or they can be IR sensors, Infra Red sensors. The function of the sensors will be described in more detail later in this text.

The sensor unit or units may be connected to the control unit 29 in a variety of manners, for example by means of cables, but in one embodiment, the sensor units, in addition to comprising the sensors, as indicated in fig 2, are also equipped with means for wireless communication with the control unit, so that the sensor units can receive control signals from the control unit and so that the sensor units, are also able to transmit detection or absence of detection of objects to the control unit. The wireless communication can be either by means of radio signals, or by means of IR-signals.

Furthermore, as indicated in fig 2, in one embodiment of the invention, at least one sensor unit 22 is adapted to act as a "relay station" between the control unit 29 and the other sensor unit 21 , i.e. the "relay station" 22 is arranged to transmit communication between the other sensor units and the control unit. Thus, the relay station 22 can receive communication from the sensor unit 21 which is intended for the control unit 29, and can forward it to the control unit 29, and vice versa, can receive communications from the control unit 29 which is intended for the sensor unit 21 , and can forward this to the sensor unit 21. Naturally, the sensor unit 22 can also receive communications intended for itself, and can transmit its own detections or absence of such to the control unit 29.

Turning now to the nature of the sensors in the sensor units, a top view of the basic function of these sensors is shown in fig 3, using the basic situation of fig 1 , i.e. the situation with an overtaking vehicle 10, 10' and a vehicle 12 which is being overtaken.

The sensor in the sensor unit 22 is, as described above, an active sensor, and can detect the presence or absence of objects within a certain first predetermined distance R1 in a direction which is suitably lateral from the sensor, so that if the sensor unit 22 is arranged on the side of the vehicle 10, the sensor will be able to detect if there are objects within the distance R1 laterally, i.e. to the side of the vehicle 10.

Naturally, the direction in which the sensor can detect objects within the distance R1 can be set, either by the driver or when producing the sensors, so that the perpendicular direction is only an example intended to illustrate a principle. The same is true for the detection distance R1 : R1 can be set by the driver or by another operator of the system 20, as an alternative to which it can be set by the manufacturer when producing the sensors or the system.

R1 should however usually be such that the sensors will be able to detect objects, which will primarily of course be other vehicles, within a distance R1 which corresponds to the width of a typical lane on a highway or expressway, since detection of objects in lanes which are not immediately adjacent to the own lane is not of interest but may conversely lead the driver to erroneous conclusions.

In addition, in a preferred embodiment, the system of the invention should also be able to detect if the vehicle which carries the system has passed an object such as another vehicle 12 by a certain margin R2. For this purpose, suitably, the sensor of at least one sensor unit in the system should be able to also detect objects within a second predetermined distance within a predetermined angular range α from the perpendicular direction. In this way, if a plurality of sensor units is arranged on the side of a vehicle, the sensor unit which is able to detect in the angular range α can be arranged as the rearmost sensor unit, as shown in fig 3. The second predetermined distance can be the same as the first distance R1 , or it can be another distance.

Fig 4 shows another version of the sensor units in the system of the invention: the vehicle 10 is equipped with a plurality of sensor units 21-24 on each of its sides. Each sensor unit can detect objects within an angular range β, and the sensors are arranged along the sides of the vehicle 10 in a manner which takes the range β into account, in order to get a sufficient overlap of coverage between the sensor units.

The range coverage, i.e. the detection of objects within the distance R1 , is suitably handled by means of software in the sensor units or in the control unit. Thus, if the sensor unit 21 detects any objects within the range β and inside the distance R1 , it transmits this detection to the control unit, which can collate all detections from the sensor units in order to create a good overview for the driver of the vehicle.

Fig 5 shows yet another version of the sensors 21-24 of the system of the invention: in this version, each sensor can only detect objects which are, for example, laterally located relative to the sensor, and which are within a length which corresponds to the sensor's length. However, in order to obtain coverage in the rear direction, the rearmost sensor 21 on at least one of the sides of the vehicle 10 has an angular detection range which deviates from the lateral direction in at least one direction by means of an angle α. If this version of the sensors is used, the sensors should suitably be arranged on the sides of the vehicle at a minimum distance Dmin from each other, in order to detect objects of a predetermined size.

Fig 6 shows a further version of the system 20 of the invention: as opposed to the version shown in fig 2, the sensor units 21 , 22, in this version are equipped with means for communicating directly with the control unit 29, i.e. in this embodiment there is no "relay station", which was the case in the embodiment shown in fig 2. Naturally, these embodiments can be combined, so that some sensor units communicate directly with the control unit, and others do so via a relay station. Also, in one embodiment, there is a "chain" of relay stations, so that a sensor collects data from/to the sensor next to it, and relays this to/from the next sensor, so that a chain of communication is established between the sensor units in the system and the control unit 29.

As mentioned previously, the sensor or sensors in the system of the invention are activated and/or deactivated by the control unit for sensing when certain predetermined criteria are fulfilled. A simple solution to this is to equip the control unit with a button which the driver presses when wishing to activate the sensors, for example when the driver has overtaken or is in the process of overtaking another vehicle.

Another solution to how the sensors may be activated is indicated in fig 7, in which a steering wheel 70 of a vehicle is shown. Also shown is the lever 71 for activating the turn indicators of the vehicle. In one embodiment of the invention, the control unit is adapted to be connected to the turn indicator in such a way that when the driver indicates a turn in one direction, the sensors on that side of the vehicle are activated.

However, if the sensors are always activated when the driver indicates a turn in a certain direction, a problem may arise if the vehicle for example, already is on the innermost lane of a highway, and the driver signals for a turn in order to take the next exit from the highway. In this case, the sensors on the innermost side will be activated, and may detect any amount of objects, such as side rails, trees, lamp posts etc.

A solution to this is to let the turn indication lever 71 activate the sensors to one side if the lever 71 is moved less than the entire distance needed to activate the turn indicators, i.e. a "light" pressure on the lever 71 will activate the sensors but not the turn indicators. In this way, the driver can check if there are any objects to one side or the other before actually deciding to make the turn, and if the vehicle is already in the innermost lane, the driver can simply desist from making the check, and can instead activate the turn indicators on one side of the vehicle by moving the lever 71 to that position.

Alternatively, as also indicated in fig 7, the turn indicator lever 71 can be outfitted with a special button 72 for activating the sensors. In order to make it easy to activate the sensors on either side of the vehicle, the lever 71 may in fact be equipped with two buttons 72, 72', one for activating the sensors on either side. Naturally, this can also be done by means of one button which can be moved between two positions. Also, if separate buttons are used, they do not need to be fixed to the lever 71 , but can be arranged more or less anywhere within easy reach of the driver.

In addition, if detections of objects such as trees, lamp posts, rails etc which are not actually obstacles to overtaking another vehicle is seen as a problem, it is possible, in one embodiment of the invention, to equip the sensor units with a function which can detect the speed with which a detected object moves. In such a case, objects which move with a relative speed which is less than a certain absolute threshold speed, or objects which move with a speed which is less than a certain speed relative to the speed of the vehicle in which the system is installed can be discriminated against, for example in such a way that objects which fulfil the criteria described are not even displayed on the control unit. This can, for example, be achieved by means of software in the sensors or sensor units or in the control unit. If the sensors are radar sensors, so called MTI technology may be used to discriminate against objects below a certain speed, where MTI stands for Moving Target Indication.

Another advantage of equipping the system or the sensor of the system with a function which can detect the speed of detected objects is that the driver can be informed of the expected result of trying to pass another vehicle: if the speed of the vehicle which the driver is trying to pass or overtake is such that the overtaking can be expected to take a very long time, the driver can be informed of this, so that he, for example, can slow down and return to an inner lane.

The system of the invention also comprises indication means which are connected to the control unit of the system, for indicating to, for example, the driver if the sensor unit or units has/have detected objects or not. The term "connected to" is here is used in a wide sense, so that the connection may be by means of cables or it may be wireless, for example by means of radio or IR-signals.

The information from the system of the invention to the driver of the vehicle can be indicated or signalled in a large number of ways. In a simple embodiment, there is simply a green or a red lamp or diode, which indicate the presence or absence of objects on one side of the vehicle, and at a certain distance behind the vehicle as well. Alternatively, sound signals may also be used. However, in one embodiment, the control unit is equipped with a display, which displays information from the sensors.

One example of such a display 80 is shown in fig 8. As indicated in fig 8, the display 80 of this embodiment shows a silhouette 84 of the vehicle, and can also indicate the position of the sensors 21-23, as well as showing which sensor or sensors that have detected any objects to the side or rear of the vehicle, by means of, for example using the colour red in order to display a sensor which has detected an object, and the colour green to display a sensor which has not detected any objects. In this manner, the driver can more or less exactly see where objects have been detected.

The problem of detecting objects on the side of the vehicle will be important when driving on major roads such as, for example, highways, while such detection may cause problems when driving in a more urban environment, for example in a city centre. In order to be able to adapt to such an environment as well, the sensors in the sensor units can, in one embodiment, be set to be active or not, depending on the speed with which the vehicle is moving. This speed can be set by the manufacturer, or the control unit can be equipped with means which will make it possible to enter this "speed limit". Using such a possibility, an operator of the system, usually the driver, can set the system so that detections are enabled for a speed above, for example, 70 km/h, and disabled for speeds below this. In such an embodiment, the control unit of course needs to be connected to a unit in the vehicle which can inform the control unit of the vehicle's speed. The settings can be as simple as "city/highway", or the settings can be explicit speeds.

Also, with heavy vehicles such as trucks, with or without trailers, it is common for the driver to stow long loads on the vehicle, so that the load may protrude behind the rearmost part of the vehicle as such. In order to make the system of the invention more useful for such a possibility as well, in one embodiment of the invention, the control unit comprises means by which an operator (e.g. the driver) of the system can adjust the oblique angular range within which detections are made, which depending on the embodiment will be the angle shown as α or β in figs 3-5, in order to correspond to a varied effective length of the vehicle. Also, the rearwards detection angle/distance can be adaptive depending on the speed of the vehicle. Furthermore, since different roads may be of different widths, in one embodiment of the system of the invention, the driver (or another operator of the system) can, from the control unit, adjust the perpendicular detection distance, i.e. the distance "R" of fig 3.

In some situations, there can be a danger for the driver not in overtaking another vehicle, but in being overtaken, for example being overtaken on the inside of the vehicle. In such a case, another vehicle may appear suddenly on one of the sides of the vehicle, i.e. to the right/left of the vehicle. Such an overtaking vehicle may be very close to the vehicle in which the system of the invention is installed, in fact so close that there is a risk of a collision or of having protruding equipment such as the rear view mirrors damaged. In order to alert the driver of the vehicle in which the inventive system is installed to such dangers, in one embodiment of the invention, the sensors are always active for sensing within a third predetermined distance which is smaller than the first predetermined distance. Thus, for example, this "inner" distance may correspond to the length with which the rear view mirrors or other protruding equipment protrudes perpendicularly from the vehicle, which can be with a margin or not.

The system of the invention has so far been described as being used in order to facilitate overtaking other vehicles, or to warn of overtaking vehicles. However, another field of application for the invention is to warn of the illicit presence of people within a certain distance of the vehicle when the vehicle is parked. Thefts from heavy vehicles which are parked is a common problem, and in order to assist in preventing such occurrences, the system of the present invention can be equipped with a mode of operation in which the sensors are active even when the vehicle is parked. Thus, the system, in such an embodiment would comprise an automatic or manual ON/OFF switch for activating or deactivating the system in a standstill position of the vehicle, so that detection may be made of people (or other moving objects) within the detection distance of the sensors, which could be the same in the standstill position as otherwise, or there could be a special "standstill detection range".

The system of the invention can also be useful when driving the vehicle in the backwards direction, a situation which is particularly accident-prone. In such an embodiment, the sensors could always be activated for detection when the vehicle moves backwards, or there could be an ON/OFF setting on the control unit for activating the sensors.

Also, the detection distance/angle could be different when backing the vehicle, so that the distance for example, is decreased, but such that the system will still be able to detect, for example, children, who approach the vehicle in this situation. Naturally, in this embodiment, the control unit needs to be equipped with the possibility of detecting that the vehicle is moving backwards, which can be accomplished by means of, for example, connecting the control unit to the gearstick of the vehicle.

Fig 9 shows a side view of a vehicle 10 equipped with a system 20 of the invention. The vehicle 10 is a heavy vehicle to which a trailer 10' is attached. On both sides (although only one side is shown in fig 9) of the vehicle 10 and the trailer 10', a plurality of sensor units 18-22 are attached, which function according to one or more of the embodiments described above. As indicated, the sensor units communicate "in relay", i.e. each sensor unit 18-22 communicates with the sensor or sensors which are immediately adjacent to the sensor unit, and the sensor unit 22 which is the closest to the control unit 29 which is installed in the cabin of the vehicle communicates with the control unit 29, and "relays" communication to/from the other sensor units as well as to/from itself. Each sensor unit can also be seen as a node in a wireless network which consists of the sensor units and the control unit. The invention is not limited to the examples of embodiments described above and shown in the drawings, but may be freely varied within the scope of the appended claims.

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Claims

1. A lane change assistance system (20) for a vehicle (10, 10'), comprising at least one sensor unit (18, 19, 20, 21 , 22, 23, 24) for arrangement on said vehicle (10, 10') and a control unit (29) adapted for installation in said vehicle (10, 10') and arranged for the control of and communication with the at least one sensor unit (18, 19, 20, 21 , 22, 23, 24), the system (20) being characterized in that the at least one sensor unit comprises an active sensor which is adapted to transmit signals and to receive reflections of said transmitted signals in order to detect objects within a first predetermined distance (R1) in a substantially lateral direction from the vehicle, with the sensor of the at least one sensor unit being activated and/or deactivated by

, the control unit (29) when certain predetermined criteria are fulfilled, the system also comprising indication means (80) connected to the control unit for indicating the detection of objects by the system.

2. The system (20) of claim 1 , further comprising means for wireless communication between the control unit and the sensor unit, in order for the sensor unit to receive control signals and to transmit the detection or absence of detection of objects to the control unit (29)

3. The system (20) of claim 1 or 2, comprising two or more sensor units (18, 19, 20, 21 , 22, 23, 24) with active sensors, at least one of which active sensors is also arranged to detect the presence of objects which are within a second predetermined distance (R2) within a predetermined oblique angular range (α, β) from the vehicle.

4. The system (20) of claim 3, in which each sensor unit (18, 19, 20, 21 , 22, 23, 24) is adapted to communicate wirelessly with the control unit (29) individually.

5. The system (20) of claim 3, in which at least one sensor unit (18, 19, 20, 21 , 22, 23, 24) is adapted to communicate with at least one other sensor unit wirelessly, and in which system at least one sensor unit (22) is adapted to act as a "relay station" between the control unit and the other sensor unit or units, i.e. the "relay station" is arranged to transmit communication between other sensor units and the control unit (29).

6. The system (20) of any of claims 2-5, in which said wireless communication is by means of radio signals.

7. The system (20) of any of claims 2-5, in which said wireless communication is by means of IR- signals.

8. The system (20) of any of claims 1-7, in which the sensor or sensors is/are IR-sensors.

9. The system (20) of any of claims 1-7, in which the sensor or sensors is/are radar sensors.

10. The system (20) of any of claims 1-9, in which the control unit (29) is arranged to be connected to a turn indicator control in the vehicle (10, 10'), so that an activation command is performed from the turn indicator (71), by means of which one or more sensors arranged for detection in a certain direction is/are be activated.

11. The system (20) of claim 10, in which said command is activation of the turn indicator control (71).

12. The system (20) of any of claims 1-11 , in which the control unit (29) comprises means by which an operator of the system can indicate a certain speed range of the vehicle (10, 10') within which the sensors of the sensor units will not be activated.

13. The system (20) of any of claims 3-12 in which the control unit (29) comprises means by which an operator of the system can adjust said oblique angular range (α, β), in order to correspond to a varied effective length of the vehicle (10, 10').

14. The system (20) of any of claims 1-13 in which the control unit (29) comprises means by which an operator of the system can adjust said first predetermined lateral distance (R1).

15. A vehicle (10, 10') fitted with the system (20) of any of clams 1-14.