WO2019147178A1

WO2019147178A1 - Method and control unit for braking a vehicle

Info

Publication number: WO2019147178A1
Application number: PCT/SE2019/050018
Authority: WO
Inventors: André Claesson
Original assignee: Scania CV AB
Current assignee: Scania CV AB
Priority date: 2018-01-26
Filing date: 2019-01-14
Publication date: 2019-08-01
Anticipated expiration: 2020-07-26
Also published as: DE112019000290T5; SE1850090A1; SE543017C2

Abstract

A method and a control unit for a vehicle arranged for transporting one or more passengers are presented. The vehicle includes at least one communication device arranged for communication with at least one entity external to the vehicle. The method includes: - determining, based on information provided by the at least one communication device, a time period tchange until a color change of a traffic light; - determining a vehicle speed v; - determining a distance d to a stop position pstop at the traffic light; - determining a deceleration sensibility Dsense of the one or more passengers; - determining, based on tchange, v, d and Dsense, braking features for achieving a vehicle standstill at the stop position pstop including one or more of an initiation point in time tbrake and a rate Drate of the deceleration; and - performing at least one action usage of the determined braking features.

Description

METHOD AND CONTROL UNIT FOR BRAKING A VEHICLE

Technical field

The present invention relates to a vehicle, and in particular to a method and a control unit for braking a vehicle arranged for transporting one or more passengers. The present invention also relates to a computer program and a computer-readable medium that implement the method according to the invention.

Background

The following background description constitutes a description of the background to the present invention, which does not, however, necessarily have to constitute prior art.

Vehicles transporting one or more passengers, such as e.g. buses, are often used in areas having traffic lights arranged along the roads or streets for controlling the vehicle traffic flow. In, for example urban areas, such as in cities, a bus will normally encounter a number of traffic lights during its route. As is well known, the traffic lights may indicate that vehicles are allowed to pass the traffic light, e.g. by displaying a green color, may indicate that vehicles should be braked and stop, e.g. by displaying a yellow light, or may indicate that vehicles are not allowed to pass the traffic light, e.g. by displaying a red light.

A driver of the vehicle should thus react based on the indications provided by the traffic lights, e.g. based on the color displayed by the traffic lights. Thus, the driver adapts the driving related actions/maneuvers being performed based on the indications provided by the traffic lights. For example, if an upcoming traffic light displays a green light, the driver may proceed towards, and may pass, the traffic light without performing any additional actions. However, if the upcoming traffic light displays a yellow or red light, the driver will typically brake the vehicle, such that the vehicle speed is reduced, and such that the vehicle is stopped at the traffic light. The driver will then have to wait until the traffic light displays a green light again, and may then pass the traffic light. Brief description of the invention

When approaching a traffic light with a vehicle arranged for transporting one or more passengers, the driver will have to brake the vehicle if the traffic light changes from displaying a green color, indicating that the vehicle may pass, to displaying a yellow or a red color, indicating that the vehicle should stop. Such braking of the vehicle at a traffic light might cause discomfort for the one or more passengers in the bus.

Especially, if the change in the displayed traffic light color is spotted/detected late, i.e. when the vehicle is close to the traffic light, the driver might have to

aggressively/sharply brake the vehicle in order to make a full stop at the traffic light. Such an aggressive/sharp braking of the vehicle may cause discomfort, and may even be dangerous, for the passengers of the vehicle, especially if the passengers are not healthy, are not seated and/or are not properly using safety/seat belts.

In some vehicles, such as for example buses, military vehicles, fire trucks, or ambulances, passengers are often not using safety/seat belts. Also, in some of these vehicles, passengers are often standing, e.g. bus passengers are often standing in the gangways since there were no available seats for them in crowded buses. For such standing passengers, an aggressive/sharp braking before a traffic light may cause a great discomfort, and may also be dangerous, since there is a risk for the passengers that they trip and/or fall due to the aggressive retardation of the vehicle.

Some passengers are extra sensitive to aggressive braking/retardation, such as e.g. older passengers, younger passengers (i.e. children), injured passengers, ill passengers and/or disabled passengers, since they may not reach a

grip/handle/knob or may not have the strength to hold on to a grip/handle/knob or the like in the bus when the braking occurs. Also, passengers sitting in wheel chairs, passengers carrying luggage and/or passengers with a baby carriage may also be extra sensitive to aggressive braking/retardation, since they may be unable to reach for a grip/handle/knob or the like in the bus when the braking occurs.

A city bus travelling during rush hours, for example, may have many standing passengers, and may also carry one or more other extra sensitive passengers. Also, a city bus will normally pass a number of traffic lights during its route, and the driver may thus be forced to perform a number of more or less aggressive/sharp braking actions, which may be dangerous for the passengers.

It is therefore an objective of the present invention to provide a method and a control unit for braking a vehicle arranged for transporting one or more passengers such that these problems are at least partly solved.

According to an aspect of the present invention, this objective is achieved through the above-mentioned method for braking a vehicle arranged for transporting one or more passengers, the vehicle including:

- at least one communication device arranged for communication with at least one entity external to the vehicle;

the method including:

- determining, based on information provided by the at least one communication device, a time period tchange until a color of a traffic light ahead of the vehicle will change;

- determining a vehicle speed v;

- determining a distance d to a stop position p_stop at the traffic light;

- determining a deceleration sensibility Dsense of the one or more passengers;

- determining, based on the time period tchange, the vehicle speed v, the distance d and the deceleration sensibility Dsense, braking features usable for achieving a vehicle standstill at the stop position p_stop, the braking features including one or more in the group of:

- a point in time tbrake at which a deceleration should be initiated; and

- a rate D_rate of the deceleration to be used; and

- performing at least one action related to braking of the vehicle by usage of the determined braking features.

Hereby, a smooth and comfort braking of a vehicle arranged for transporting one or more passengers may be achieved when the vehicle approaches a traffic light changing its displayed color, e.g. from displaying a green color to displaying a yellow or a red color. The braking features may be determined early, before the change in displayed traffic light color occurs and possibly even before a driver of the vehicle can see the traffic light at all, whereby valuable additional time is gained, which may be used for providing a smooth braking of the vehicle. Thus, the driver may be requested to start braking the vehicle although the traffic light is still displaying a green light, if it is determined that the traffic light will change to yellow and/or red before the vehicle will have passed the traffic light. Also, the driver may be requested to start braking the vehicle before the vehicle has advanced enough for the driver to be able to see the traffic light, if it is determined that the traffic light will change to yellow and/or red before the vehicle will have passed the traffic light.

Thus, due to the gained additional time useable for braking the vehicle, sudden and/or aggressive braking operations may be avoided when the present invention is used, which improves safety and comfort for the passengers, e.g. for passengers not being healthy, not being seated and/or not properly using safety/seat belts. For example, the risk for standing passengers to fall in buses carrying standing passengers is minimized by usage of the embodiments of the present invention.

According to an embodiment of the present invention, the determining of the time period tchange is based on one or more in the group of:

- information provided by the traffic light;

- information provided by a unit associated with the traffic light;

- information provided by at least one other vehicle; and

- information previously gathered by the vehicle.

Based on one or more of these types of information, the time period tchange until a change of the color of the traffic light may be reliably determined with little additional complexity.

According to an embodiment of the present invention, the determining of the time period tchange is performed before the traffic light is visible from the vehicle. Hereby, a smooth and well controlled braking of the vehicle is achievable.

It may thus be possible to determine the time period tchange until a change of the color of the traffic light before the traffic light is visible from the vehicle, since the time period tchange may be determined at least partly based on information provided by external entities, other vehicles and/or on information previously gathered by the vehicle itself. Obviously, the time period tchange may be determined before the displayed traffic light color changes; tchange > 0. Hereby, a smoother and a less aggressive braking over a longer time period may be used for braking the vehicle. According to an embodiment of the present invention, the determining of the distance d is based on one or more in the group of:

- positioning information;

- map information;

- camera information;

- radar information;

- information provided by at least one other vehicle; and

- information previously gathered by the vehicle.

Hereby, a reliable determination of the distance d to a stop position p_stop at the upcoming traffic light is provided. Since a number of different types of information may be used for the determination, the determination of the distance d to a stop position p_stop may essentially always be reliably and accurately performed. Also, the information used as a basis for the determination is usually available in the vehicle, since it is used by other vehicle systems, wherefore the complexity added for performing the determination is low.

According to an embodiment of the present invention, the determining of the deceleration sensibility Dsense of the one or more passengers includes determining if at least one of the one or more passengers is standing.

Hereby, a common and potentially dangerous situation for e.g. buses operating in urban areas is taken care of. The problem of standing passengers being exposed to unpleasant and potentially dangerous falling or tripping is common in crowded buses, in which standing passengers might not be able to hold on to a grip/handle/knob or the like in the bus. However, when the embodiment of the present invention is used, standing passengers are specifically taken into account when the braking features are determined, which considerably reduces the risk for discomfort of standing passengers.

According to an embodiment of the present invention, the determining of the deceleration sensibility Dsense of the one or more passengers is based on information provided by at least one on board monitoring system.

Hereby, a reliable and accurate determination of the deceleration sensibility Dsense of the one or more passengers is provided. According to an embodiment of the present invention, the determining of the deceleration sensibility Dsense of the one or more passengers is based on one or more in the group of:

- visual information provided by at least one camera device on board of the vehicle;

- tactile information provided by at least one pressure sensor device arranged at the floor of the vehicle;

- curvature information for at least one part of a road section between the vehicle and the traffic light;

- driver input information;

- information related to usage of a wheel chair safety belt;

- information previously gathered by the vehicle; and

- information provided by at least one other vehicle.

Thus, a variety of information may be used for determining the deceleration sensibility Dsense of the one or more passengers, which increases the accuracy and reliability of the determination. Also, one or more of these types of information are usually available in the vehicle, since they are used by other vehicle systems, wherefore the embodiments may be implemented with little additional complexity, e.g. with no additional hardware complexity.

According to an embodiment of the present invention, the determining of the braking features is also based on a friction between one or more vehicle tires and at least one part of a road section between the vehicle and the traffic light.

Hereby, slippery road sections, such as e.g. icy, muddy and/or wet road sections, may be taken into consideration when determining the braking features, which increases the possibility of performing a smooth braking operation which guarantees that the vehicle is stopped at the stop position p_stop.

According to an embodiment of the present invention, the friction is determined based on one or more in the group of:

- visual information for at least one part of a road section between the vehicle and the traffic light provided by at least one camera device of the vehicle;

- information related to at least one activation of an anti-lock braking system (ABS) of the vehicle; - information related to the one or more vehicle tires;

- ambient temperature information;

- information previously gathered by the vehicle;

- information provided by at least one other vehicle; and

- information provided by at least one infrastructure device.

Since the friction may be determined based on information provided by one or more different entities providing one or more different types of data/information, it will essentially always be possible to identify a slippery road section.

According to an embodiment of the present invention, the determining of the braking features is performed in relation to the deceleration sensibility Dsense such that a risk for passenger discomfort is eliminated.

For example, a higher deceleration sensibility Dsense may hereby result in a lower deceleration rate Drate for the braking and/or in an earlier point in time tbrake for initiating/starting the braking, whereby the risk for passenger discomfort and/or injury of e.g. standing and/or older passengers is reduced.

According to an embodiment of the present invention, the performing of at least one action related to braking of the vehicle includes at least one in the group of:

- providing an indication to a driver of the vehicle, the indication requesting a braking according to the braking features to be performed by the driver;

- providing an indication to a driver of the vehicle, the indication requesting a braking according to the braking features to be performed by the driver, and, if the driver fails to perform the requested braking, actively controlling at least one braking system to perform the requested braking; and

- actively controlling at least one braking system to perform the requested braking.

Passenger safety and comfort is hereby secured, since the driver is made aware of when it is time to start braking, and/or is provided with an indication of how the braking is to be performed. For example, a lamp/light may be activated when it is time to start braking, i.e. at the deceleration initiation point in time tbrake, and/or the lamp/light may display various colors indicating if the deceleration rate Drate should be changed, or if the used deceleration rate Drate is adequate/acceptable. Also, a speaker may be activated to output a sound/message at the deceleration initiation point in time tbrake and/or to output various sounds/messages indicating if the deceleration rate D_rate should be changed, or if the used deceleration rate D_rate is adequate/acceptable. However, if the driver fails to follow the instructions/indications, an automatic braking may be performed according to an embodiment, which further increases the probability for a comfortable braking. Also, a completely automatic braking may, according to an embodiment, be performed, e.g. for an autonomous vehicle.

According to an aspect of the present invention, the objective is achieved through the above-mentioned control unit for a vehicle arranged for transporting one or more passengers. The vehicle includes at least one communication device arranged for communication with at least one entity external to the vehicle. The control unit is configured for:

- determining a vehicle speed v;

- determining a distance d to a stop position p_stop at the traffic light;

- determining a deceleration sensibility Dsense of the one or more passengers;

- a point in time tbrake at which a deceleration should be initiated; and

- a rate Drate of the deceleration to be used; and

It will be appreciated that all the embodiments described for the method aspect of the invention are applicable also to the control unit aspect of the invention. Thus, all the embodiments described for the method aspect of the invention may be performed by the control unit, which may also be a control device, i.e. a device. The control unit and its embodiments have advantages corresponding to the advantages mentioned above for the method and its embodiments. According to an aspect of the present invention, a vehicle including a control unit as described herein is presented.

According to an aspect of the present invention, the above-mentioned computer program and computer-readable medium are configured to implement the method and its embodiments described herein.

Brief list of figures

Embodiments of the invention will be illustrated in more detail below, along with the enclosed drawings, where similar references are used for similar parts, and where:

Figure 1 shows an example vehicle, in which embodiments of the present invention may be implemented,

Figure 2 shows a flow chart for methods according to some embodiments of the present the invention,

Figure 3 schematically illustrates a vehicle approaching a traffic light.

Figure 4 schematically illustrates a vehicle approaching a traffic light, and some other vehicles communicating with the vehicle, and

Figure 5 shows a control unit, in which a method according to any one of the herein described embodiments may be implemented.

Description of preferred embodiments

Figure 1 schematically shows an exemplary heavy vehicle 100, such as a truck, a bus, a fire truck or another heavy vehicle, which will be used to explain the herein presented embodiments. The embodiments are, however, not limited to use in heavy vehicles as the ones shown in figure 1 , but may also be used in lighter vehicles such as passenger cars, ambulances or the like.

A vehicle 100, as shown schematically in Figures 1 , comprises a pair of drive wheels 11 1 , 1 12 and at least one other pair of wheels 1 13, 1 14. The vehicle furthermore comprises a drivetrain configured to transfer a torque between at least one power source, such as e.g. an engine 101 , and the drive wheels 1 1 1 , 112. The at least one power source may include a combustion engine 101 , at least one electrical machine, or a combination of these, implementing a so-called hybrid drive.

The at least one power source 101 is for example in a customary fashion, via an output shaft 102 of the engine 101 , connected to a clutch 106, and via the clutch also to a gearbox 103. The torque provided by the engine 101 is provided to an input shaft 109 of the gearbox 103. A propeller shaft 107, connected to an output shaft of the gearbox 103, drives the drive wheels 11 1 , 1 12 via a central gear 108, such as e.g. a customary differential, and drive shafts 104, 105 connected with the central gear 108.

The vehicle 100 also includes at least one braking arrangement 151 , 152, 153, 154, for example one braking arrangement 151 , 152, 153, 154 arranged at each one of the wheels of the vehicle. The at least one braking arrangement 151 , 152, 153, 154 may be included in at least one braking system 150. Braking of the vehicle 100, i.e. a retardation of the vehicle 100, by use of the at least one braking arrangement 151 ,

152, 153, 154 may be achieved in a number of well known ways. The at least one braking system 150 may also include one or more additional braking devices 155, for example one or more braking devices acting on the drivetrain, such as a retarder, and/or an exhaust brake device. The at least one braking system 150, including the at least one braking arrangement 151 , 152, 153, 154 and/or the at least one additional braking device 155 may be controlled by at least one control unit/device 160, which is described more in detail below.

The control unit/device 160 may include a first determination unit 161 , a second determination unit 162, a third determination unit 163, a fourth determination unit 164, a fifth determination unit 165, and an action performing unit 166, as is

mentioned below. The control unit/device 160 and/or another control unit/device may further be configured for controlling one or more of the at least one power source 101 , the clutch 106, the gearbox 103, and/or any other units/devices/entities of the vehicle. However, in figure 1 , only the units/devices/entities of the vehicle useful for understanding the present invention are illustrated.

The vehicle 100 may further include at least one indication output 175, arranged for presenting indications to the driver, such as visual, audio and/or tactile indications using for example lights, sounds and/or vibrations presented in the instrument cluster, the on windshield and/or in the driver seat. The at least one indication output 175 may be controlled by the control unit 160.

Also, the vehicle 100 may include at least one monitoring system 130 arranged for onboard monitoring of the vehicle, as is described more in detail below.

Figure 2 shows a flow chart for a method 200 for braking a vehicle 100 arranged for transporting one or more passengers 120, according to an embodiment of the present invention. The vehicle 100, which includes at least one communication device 170 arranged for communication with at least one entity 190, 180, 181 , 185 external to the vehicle 100, is illustrated in figures 3 and 4. Figure 3 schematically illustrates the vehicle 100 approaching a traffic light 190 and communicating with at least one external entity 190, 180. Figure 4 schematically illustrates the vehicle 100 approaching a traffic light 190 and communicating with at least one other vehicle 185 and/or with at least one other external entity 180, 181. Figures 3 and 4 may be useful for understanding the embodiments of the present invention described below. It should be noted that the method steps illustrated in figure 2 and described herein do not necessarily have to be executed in the order illustrated in figure 2. The steps may essentially be executed in any suitable order, as long as the physical

requirements and the information needed to execute each step is available when the step is executed. In a first step 210, a time period tchange until a color of a traffic light 190 ahead of the vehicle 100 will change is determined based on information provided by the at least one communication device 170. For example, the time period tchange until the traffic light 190 will change/turn from green (G) to yellow (Y), or until the traffic light 190 will change/turn from yellow (Y) to red (R), is here determined based on information received from offboard the vehicle, i.e. from the at least one external entity 180, 181 ,

185, which is provided by the at least one communication device 170. Thus, the at least one communication device 170 is arranged for communicating with the at least one external entity 180, 181 , 185, and may thereby provide the information needed for determining the time period tchange. In a second step 220, a vehicle speed v, at which the vehicle 100 is travelling is determined. The vehicle speed may be determined in a number of conventional ways, e.g. based on positioning information and/or on a wheel rotational speed.

In a third step 230, a distance d to a stop position p_stop at the upcoming traffic light 190 is determined. The stop position p_stop may here be located directly at the traffic light 191 , if there is no queue at the traffic light 190, or may be located after one or more vehicles queueing at the traffic light 190, i.e. before/upstream the traffic light position 191 in the direction of the vehicle movement.

In a fourth step 240, a deceleration sensibility Dsense of the one or more passengers 1 20 is determined. This determination may be performed according to one or more below described embodiments.

In a fifth step 250, braking features usable for achieving a vehicle standstill at the stop position p_stop are determined. The braking features include a point in time tbrake at which a deceleration/retardation of the vehicle 100 should be initiated and/or a rate Drate of the deceleration to be used, i.e. how aggressive/sharp the

deceleration/retardation should be. The determination of these braking features is described below for various embodiments of the present invention.

In a sixth step 260, at least one action related to braking of the vehicle 100 is performed by usage of the determined braking features. According to various embodiments of the present invention, the at least one communication device 170 may be essentially any device transferring information to and/or from the vehicle, and the at least one entity 180, 181 , 185 external to the vehicle 100 may be essentially any external entity communicating with the at least one communication device 170 for the transfer of the information to and/or from the vehicle. Thus, the at least one external entity 180, 181 , 185 may e.g. be associated with, such as being included in, an infrastructure entity and/or another vehicle.

Correspondingly, the at least one communication device 170 may be a vehicle-to- vehicle (V2V) communication device, a vehicle-to-infrastructure (V2I) communication device, and/or a vehicle-to-everything (V2X) communication device, such that communication between the vehicle and the at least one external entity 180, 181 ,

185 is achieved.

By the use of the presented method, a vehicle arranged for transporting one or more passengers may be smoothly braked if the vehicle approaches a traffic light changing its displayed color, e.g. changing from displaying a green color to displaying a yellow or a red color. The braking of the vehicle provided by the embodiments of the present invention may thus be achieved while securing the comfort for the one or more passengers of the vehicle.

Since the braking features are determined based on information provided by the at least one communication device 170, which is arranged for communication with the at least one external entity 180, 181 , 185, e.g. an infrastructure and/or other vehicle entity, the braking features may be determined early. In some situations, the braking features may be determined already before a driver of the vehicle can see the traffic light 190. Thus, features of a controlled braking action may hereby be determined even before the driver himself is aware of that the vehicle needs to be braked.

Hereby, the braking of the vehicle may be performed much earlier than what has been possible in conventional solutions. Valuable additional time, which may be used for braking the vehicle 100, is hereby gained, which greatly increases the possibilities for smooth braking.

Thus, when the embodiments of the present invention are used, a driver of the vehicle and/or an active braking control system will not be forced to perform sudden and aggressive braking operations due to surprising changes of traffic light colors, e.g. from green (G) to yellow (Y) or from yellow (Y) to red (R), since information related to the changes of traffic light colors will always be available in the vehicle before the changes occur, and will be usable for initiating the braking and also for providing a smooth and comfortable braking.

Especially, the safety and comfort for passengers not being healthy, not being seated and/or not properly using safety/seat belts is hereby improved. For example, the risk for standing passengers to fall in buses carrying standing passengers is minimized by usage of the embodiments of the present invention. According to various embodiments of the present invention, the determination 210 of the time period tchange is based on information received from the at least one external entity 180, 181 , 185. The information may here be provided by the traffic light 190 itself, e.g. in the form of signals indicating time periods until changes in the displayed traffic light color. The information may also be provided by a unit 180, 181 associated with the upcoming traffic light 190, such as an infrastructure device 180, 181 (V2I) having a wired and/or wireless connection to the traffic light 190. For example, the infrastructure device 180, 181 may include a control unit providing control signals to the traffic light 190, wherein the control signals may be used for controlling the color displayed by the traffic light 190. Such control signals may easily be used for determining time period tchange.

The information, on which the determination 210 of the time period tchange is based, may also be provided by at least one other vehicle 185 (V2V). Generally, groups of vehicles, such as e.g. buses traveling at least partly the same route, may exchange information related to the traffic lights 190, such as where they are located and how or when they change the displayed color. As is illustrated in figure 4, such information provided by at least one other vehicle 185 passing the traffic light 190 before the vehicle 100 does may hereby be utilized for reliably determining the time period tchange.

The information, on which the determination 210 of the time period tchange is based, may also be provided by the vehicle 100 itself, i.e. based on information previously gathered by the vehicle 100. Vehicles often pass the same traffic lights. For example, buses often travel one route a number of times per day, whereby they also pass each traffic light of that route a number of times per day. The buses may then gather information related to a traffic light 190 at least once when they pass it, and may use this gathered information the next time that traffic light 190 is approached. As mentioned above, the gathered information may also be provided to other vehicles 185. Generally, vehicles may gather, store and/or provide essentially any information that may be useful for the vehicle itself and/or for other vehicles. This information may be retrieved and/or transmitted immediately when having been gathered and/or may be retrieved and/or transmitted later, after having been gathered, such that the vehicle, or possibly a fleet of vehicles, may use the information. The one or more vehicles may thus be seen as self-learning entities, arranged for learning from past experiences in order to improve their present and/or future performance.

Since the time period tchange until a change of the color of the traffic light 190 may be determined at least partly based on information provided by external entities 190,

180, 181 , 185 and/or on information previously gathered by the vehicle 100 itself, it is according to an embodiment, possible to determine 210 the time period tchange before the traffic light 190 is visible from the vehicle 100. The point in time tbrake at which the deceleration should be initiated may hereby be determined to an earlier time instance, such that a less aggressive braking over a longer time period may be used for braking the vehicle, compared to conventional systems, for which braking may only be initiated after the driver has actually seen/observed a change of the displayed traffic light color.

The distance d to a stop position p_stop at the upcoming traffic light 190, as is illustrated in figure 3, may be determined based on various information. The information may for example be related to vehicle positioning information, digital map information, radar-based information and/or camera-based information. The information may be previously gathered by the vehicle 100 and/or may be provided by at least one other vehicle 185. Vehicles may store information themselves and/or may share information with other vehicles 185, 100, as mentioned above. Also, the information may be obtained from traffic systems related to that road section, e.g. infrastructure systems/units/devices 190, 180, 181 . The radar and/or camera equipment providing the radar-based information and/or the camera-based information may be arranged in the vehicle 100, in another vehicle 185, at the traffic light 190 and/or at the traffic light associated entities 180, 181 .

The information related to the upcoming traffic light 190, and its location in relation to the vehicle 100, may thus be obtained in various ways. For example, it may be determined on the basis of map data, e.g. from digital maps in combination with positioning information, e.g. GPS (global positioning system) information. The positioning information may be used to determine the location of the vehicle in relation to the map data so that the distance d to a stop position p_stop at the upcoming traffic light 190 may be extracted from the map data. Various present-day cruise control systems use map data and positioning information. Such systems may then provide the map data and the positioning information needed for performing the embodiments of the present invention, thereby minimizing the additional complexity involved in determining the traffic light related information. By usage of positioning information and digital map information, the embodiments of the present invention may virtually look ahead along an upcoming road section in order to determine information related to upcoming traffic lights, that might even not yet be visible from the vehicle.

As mentioned above, standing passengers are especially vulnerable for

sharp/aggressive brakes. According to an embodiment of the present invention, this vulnerability is handled by determining 240 the deceleration sensibility Dsense of the one or more passengers 120 based on if there are standing passengers onboard the vehicle, i.e. the determination 240 of the deceleration sensibility Dsense includes determining if at least one passenger 120 is standing. This may be determined in a number of ways according to various embodiments of the present invention, e.g. based on information provided by at least one monitoring system 130 arranged on board the vehicle 100. For example, visual information provided by at least one camera device 130 on board of the vehicle 100 may be used as a basis for the determination 240 of the deceleration sensibility Dsense of the one or more passengers 120. Also, tactile information provided by at least one pressure sensor device 130 arranged e.g. at the floor of the vehicle 100 may be used as basis for the

determination 240. Some vehicles have wheel chair safety belts, and also indicators indicating if one or more wheel chair safety bels are used. Information related to usage of a wheel chair safety belt may then also be used as a basis for the determination 240 of the deceleration sensibility Dsense.

Further, the determination 240 may also be based on curvature information for at least one part of a road section between the vehicle 100 and the traffic light 190. The curvature information may be provided by usage of positioning information, e.g. GPS information in combination with map information, as mentioned above. Driver input may also be used as a basis for the deceleration sensibility Dsense determination 240. For example, if the driver of a bus notices that one or more older passengers, possibly using sticks/canes, enters the bus, the driver may input information, by use of essentially any suitable input device, which is interpreted as there are passengers on board having an increase deceleration sensibility Dsense.

The deceleration sensibility Dsense determination 240 may also be based on information previously gathered by the vehicle 100 and/or gathered and provided by at least one other vehicle 1 85 (V2V) . Hereby, a self-learning vehicle is provided, which may be adapted based on essentially any useful information gathered by the vehicle 1 00 and/or another vehicle 1 85. Thus, if it over time occurs accidents involving falling passengers at a specific traffic light, the deceleration sensibility Dsense determination 240 may take this into consideration for that traffic light. For example, the deceleration sensibility Dsense may be increased at one or more traffic lights being located after a bus stop at a hospital, at a school and/or at a home for older people. Also, the deceleration sensibility Dsense may be increased at traffic lights and/or road sections where buses usually carry many passengers, implying that a bus probably will carry standing passengers when such traffic lights and/or road sections are passed. The deceleration sensibility Dsense may also be increased at certain points in time, for example if it has previously been observed that a bus carries many passengers at those certain points in time, e.g. due to arrival of connecting buses or trains, and/or due to ending schools, concerts and the like at those points in time. Thus, essentially any information which may in any way be related to the vehicle, the passengers, the environment in which the vehicle travels, and/or the traffic light may be used as a basis for determining 240 the deceleration sensibility Dsense. The determination 240 may then include a suitable analysis of the information being useful for determining 240 the deceleration sensibility Dsense.

As mentioned above, braking features usable for achieving a vehicle standstill at the stop position p_stop are determined 250 according to various embodiments of the present invention. The braking features include at least a point in time tbrake at which a braking should be initiated and/or a rate D_rate of the deceleration to be used. The braking features may here be determined 250 based at least on the determined deceleration sensibility Dsense, e.g. such that a higher deceleration sensibility Dsense results in a lower deceleration rate Drate for the braking and/or in an earlier point in time tbrake to start braking. Hereby, i.e. since the determination 250 of the braking features is performed in relation to the deceleration sensibility Dsense, the risk for passenger discomfort and/or injury is eliminated, or is at least considerably reduced. In other words, a higher deceleration sensibility Dsense results in a smoother deceleration than a lower deceleration sensibility Dsense results in, when the determination 250 of the braking features takes the deceleration sensibility Dsense into consideration.

The determination 250 of the braking features may also be based on a friction between one or more vehicle tires 1 1 1 , 1 12, 1 13, 1 14 and at least one part of a road section between the vehicle 100 and the traffic light 190. Thus, if there is freezing degrees and/or are low friction areas 310 on the road ahead, including for example snow, ice, water, leaves, oil or some other friction reducing element, the braking features may be determined 250 such that this is taken into consideration. For example, the braking features may then be determined 250 such that the point in time tbrake at which the deceleration should be initiated is earlier, such that the vehicle is stopped without performing any braking/deceleration at the low friction areas 310. Also, the deceleration rate Drate may be adapted before and/or after the low friction areas 310, such that the vehicle is stopped without having to perform any

braking/deceleration at the low friction areas 310.

The friction between one or more vehicle tires 1 1 1 , 1 12, 1 13, 1 14 and at least one part of a road section may, according to various embodiments of the invention, be determined in a number of ways. For example, the friction determination may be based on visual information provided by at least one camera device of the vehicle 100, at least one camera device of another vehicle 185 and/or at least one camera device of an infrastructure device 190, 180, 181 . The at least one camera should then be directed towards at least one part of a road section between the vehicle 100 and the traffic light 190. Also, the friction determination may be based on ambient temperature information and/or based on information related to the one or more tires 1 1 1 , 1 12, 1 13, 1 14 of the vehicle, e.g. if they are summer type tires or winter type tires. Also, other indicators of low frictional areas may be utilized in the friction determination, such as an activation of an anti-lock braking system (ABS) of the vehicle 100, whereby a low friction may be determined if the anti-lock braking system has been activated.

Generally, the information on which the friction determination is based may be gathered/provided by the vehicle itself 100, by another vehicle 185 (V2V) and/or by at least one infrastructure device 190, 180, 181 (V2I), as is mentioned above for other types of information being exchanged between vehicles 100, 185 (V2V) and between vehicles 100, 185 and infrastructure devices 190, 180, 181 (V2I).

According to various embodiments of the present invention, the determined braking features, i.e. the braking initiation point in time tbrake and the deceleration rate Drate, may be used as a driver support 261 , 262 and/or may be used to actually control 263, 264 the braking of the braking of the vehicle 100.

As mentioned above, at least one action related to braking of the vehicle 100 is performed 260 by making use of the determined braking features. The at least one action may include providing 261 an indication to a driver of the vehicle 100 by use of the at least one indication output 175, the indication requesting the driver to perform a braking of the vehicle according to the braking features. The indication may include essentially anything that may be perceived and/or interpreted by the driver, such as visual, audio and/or tactile indications using for example lights, sounds and/or vibrations presented in the instrument cluster, on the windshield and/or in the driver seat. Any suitable output 175 may be used for conveying/presenting the indication to the driver. For example, a lamp/light/display/icon may be activated when it is time to start braking, i.e. at the deceleration initiation point in time tbrake. The

lamp/light/display/icon may display various colors, symbols and/or patters indicating if the deceleration rate Drate should be changed, or if the used deceleration rate Drate is adequate/acceptable. Also, a speaker may be activated to output a sound/message at the deceleration initiation point in time tbrake and/or to output various

sounds/messages indicating if the deceleration rate Drate should be changed, or if the used deceleration rate Drate is adequate/acceptable. Also, a certain vibration may be provided at the deceleration initiation point in time tbrake. Various vibrations, e.g. various vibration frequencies, may be used for indicating if the deceleration rate Drate should be increased or decreased.

The at least one performed 260 action may also include first providing 162 the at least one indication requesting the driver to perform the requested braking, as described above, and then, if the driver fails to perform the requested braking, actively controlling 263 a braking system to perform the requested braking. Thus, if the driver does not react to the at least one brake requesting indication, an automatic braking is activated by controlling the at least one braking system 150. Hereby, it is secured that a braking minimizing passenger discomfort is achieved, also if the driver fails to react on the indication. Also, if the driver does not react to the at least one brake requesting indication, the speed and/or fuel injection requested by a cruise control system and/or by an accelerator pedal may be automatically reduced.

For an autonomous vehicle, i.e. for a vehicle being automatically driven by one or more control systems, without influence of a physical driver, the at least one performed 260 action may also include actively controlling 264 the at least one braking system 150 to perform the requested braking, i.e. according to the

determined braking features. Also, the speed and/or fuel injection requested by a cruise control system and/or by an accelerator pedal may be automatically reduced. Thus, without including a driver input in the control of the braking system, the vehicle may hereby be smoothly and safely braked to a full stop at the traffic light 190, without having to compromise passenger comfort.

According to an aspect of the present invention, a control unit 160 for a vehicle 100 arranged for transporting one or more passengers 120 is presented. The herein described method and method embodiments may be performed by the control unit 160. The vehicle 100 includes at least one communication device 170 arranged for communication with at least one entity 190, 180, 181 , 185 external to the vehicle 100.

The control unit 160 is configured for, e.g. includes means for:

- determining 210, based on information provided by the at least one communication device 170, a time period tchange until a color of a traffic light 190 ahead of the vehicle 100 will change; - determining 220 a vehicle speed v;

- determining 230 a distance d to a stop position p_stop at the upcoming traffic light 190;

- determining 240 a deceleration sensibility Dsense of the one or more passengers 120;

- determining 250, based on the time period tchange, the vehicle speed v, the distance d and the deceleration sensibility Dsense, braking features usable for achieving a vehicle standstill at the stop position p_stop, the braking features including one or more in the group of:

- a point in time tbrake at which a deceleration should be initiated; and

- a rate D_rate of the deceleration to be used; and

- performing (260) at least one action related to braking of the vehicle 100 by usage of the determined braking features.

The control unit 160, e.g. a device or a control device, according to the present invention may be arranged for performing all of the above, in the claims, and in the herein described embodiments method steps, e.g. by including the above mentioned control units 161 , 162, 163, 164, 165, 166. The control unit 160 is hereby provided with the above described advantages for each respective embodiment. The present invention is also related to a vehicle 100, such as e.g. a truck, a bus, an ambulance or a passenger car, including the control unit 160.

The person skilled in the art will appreciate that the herein described embodiments for braking a vehicle may also be implemented in a computer program, which, when it is executed in a computer, instructs the computer to execute the method. The computer program is usually constituted by a computer program product 503 stored on a non-transitory/non-volatile digital storage medium, in which the computer program is incorporated in the computer-readable medium of the computer program product. The computer-readable medium comprises a suitable memory, such as, for example: ROM (Read-Only Memory), PROM (Programmable Read-Only Memory), EPROM (Erasable PROM), Flash memory, EEPROM (Electrically Erasable PROM), a hard disk unit, etc. Figure 5 shows in schematic representation a control unit 500/160, which may correspond to or may include one or more of the above-mentioned control units 161 ,

162, 163, 164, 165, 166, i.e. a first determination unit 161 performing the first method step 210, a second determination unit 162 performing the second method step 220, a third determination unit 163 performing the third method step 230, a fourth

determination unit 164 performing the fourth method step 240, a fifth determination unit 165 performing the fifth method step 250, and an action performing unit 166 performing the sixth method step 260. The control unit 500/160 comprises a computing unit 501 , which can be constituted by essentially any suitable type of processor or microcomputer, for example a circuit for digital signal processing (Digital Signal Processor, DSP), or a circuit having a predetermined specific function

(Application Specific Integrated Circuit, ASIC). The computing unit 501 is connected to a memory unit 502 arranged in the control unit 500/160, which memory unit provides the computing unit 501 with, for example, the stored program code and/or the stored data which the computing unit 501 requires to be able to perform

computations. The computing unit 501 is also arranged to store partial or final results of computations in the memory unit 502.

In addition, the control unit 500/160 is provided with devices 51 1 , 512, 513, 514 for receiving and transmitting input and output signals. These input and output signals can contain waveforms, impulses, or other attributes which, by the devices 511 , 513 for the reception of input signals, can be detected as information and can be converted into signals which can be processed by the computing unit 501. These signals are then made available to the computing unit 501. The devices 512, 514 for the transmission of output signals are arranged to convert signals received from the computing unit 501 in order to create output signals by, for example, modulating the signals, which can be transmitted to other parts of and/or systems in the vehicle.

Each of the connections to the devices for receiving and transmitting input and output signals can be constituted by one or more of a cable; a data bus, such as a CAN bus (Controller Area Network bus), a MOST bus (Media Orientated Systems Transport bus), or some other bus configuration; or by a wireless connection. A person skilled in the art will appreciate that the above-stated computer can be constituted by the computing unit 501 and that the above- stated memory can be constituted by the memory unit 502.

Control systems in modern vehicles commonly comprise communication bus systems consisting of one or more communication buses for linking a number of electronic control units (ECU's), or controllers, and various components located on the vehicle. Such a control system can comprise a large number of control units and the responsibility for a specific function can be divided amongst more than one control unit. Vehicles of the shown type thus often comprise significantly more control units than are shown in figures 1 and 3-5, which is well known to the person skilled in the art within this technical field.

In a shown embodiment, the present invention may be implemented by the one or more above mentioned control units 161 , 122, 163, 164, 165, 166. The invention can also, however, be implemented wholly or partially in one or more other control units already present in the vehicle, or in some control unit dedicated to the present invention.

Here and in this document, units are often described as being arranged for performing steps of the method according to the invention. This also includes that the units are designed to and/or configured to perform these method steps.

The one or more control units 161 , 162, 163, 164, 165, 166 are in figure 1 illustrated as separate units. These units 161 , 122, 163, 164, 165, 166 may, however, be logically separated but physically implemented in the same unit, or can be both logically and physically arranged together. These units 161 , 122, 163, 164, 165, 166 may for example correspond to groups of instructions, which can be in the form of programming code, that are input into, and are utilized by a processor/computing unit 501 when the units are active and/or are utilized for performing its method step, respectively.

The present invention is not limited to the above described embodiments. Instead, the present invention relates to, and encompasses all different embodiments being included within the scope of the independent claims.

Claims

1. Method (200) for braking a vehicle (100) arranged for transporting one or more passengers (120);

the vehicle including:

- at least one communication device (170) arranged for communication with at least one entity (190, 180, 181 , 185) external to the vehicle (100);

the method including:

- determining (210), based on information provided by the at least one

communication device (170), a time period tchange until a color of a traffic light (190) ahead of the vehicle (100) will change;

- determining (220) a vehicle speed v;

- determining (230) a distance d to a stop position p_stop at the traffic light (190);

- determining (240) a deceleration sensibility Dsense of the one or more passengers (120);

- determining (250), based on the time period tchange, the vehicle speed v, the distance d and the deceleration sensibility Dsense, braking features usable for achieving a vehicle standstill at the stop position p_stop, the braking features including one or more in the group of:

- a point in time tbrake at which a deceleration should be initiated; and

- a rate D_rate of the deceleration to be used; and

- performing (260) at least one action related to braking of the vehicle (100) by usage of the determined braking features.

2. Method (200) according to claim 1 , wherein the determining (210) of the time period tchange is based on one or more in the group of:

- information provided by the traffic light (190);

- information provided by a unit (180, 181 ) associated with the traffic light (190);

- information provided by at least one other vehicle (185); and

- information previously gathered by the vehicle (100).

3. Method (200) according to any one of claims 1 -2, wherein the

determining (210) of the time period tchange is performed before the traffic light (190) is visible from the vehicle (100).

4. Method (200) according to any one of claims 1 -3, wherein the

determining (230) of the distance d is based on one or more in the group of:

- positioning information;

- map information;

camera information;

- radar information;

- information provided by at least one other vehicle (185); and

- information previously gathered by the vehicle (100).

5. Method (200) according to any one of claims 1 -4, wherein the

determining (240) of the deceleration sensibility Dsense of the one or more passengers (120) includes determining if at least one of the one or more passengers (120) is standing.

6. Method (200) according to any one of claims 1 -5, wherein the

determining (240) of the deceleration sensibility Dsense of the one or more passengers (120) is based on information provided by at least one on board monitoring system

(130).

7. Method (200) according to any one of claims 1 -6, wherein the

determining (240) of the deceleration sensibility Dsense of the one or more passengers (120) is based on one or more in the group of:

- visual information provided by at least one camera device (130) on board of the vehicle (100);

- tactile information provided by at least one pressure sensor device (130) arranged at the floor of the vehicle (100);

- curvature information for at least one part of a road section between the vehicle (100) and the traffic light (190);

- driver input information;

- information related to usage of a wheel chair safety belt;

- information previously gathered by the vehicle (100); and

- information provided by at least one other vehicle (185).

8. Method (200) according to any one of claims 1 -7, wherein the

determining (250) of the braking features is also based on a friction between one or more vehicle tires (1 11 , 1 12, 1 13, 114) and at least one part of a road section between the vehicle (100) and the traffic light (190). 9. Method (200) according to claim 8, wherein the friction is determined based on one or more in the group of:

- visual information for at least one part of a road section between the vehicle (100) and the traffic light (190) provided by at least one camera device of the vehicle (100);

- information related to at least one activation of an anti-lock braking system (ABS) of the vehicle (100);

- information related to the one or more vehicle tires (1 1 1 , 1 12, 113, 1 14);

- ambient temperature information;

- information previously gathered by the vehicle (100);

- information provided by at least one other vehicle (185); and

- information provided by at least one infrastructure device (180, 181 ).

10. Method (200) according to any one of claims 1 -9, wherein the

determining (250) of the braking features is performed in relation to the deceleration sensibility Dsense such that a risk for passenger discomfort is eliminated.

11. Method (200) according to any one of claims 1 -10, wherein the performing (260) of at least one action related to braking of the vehicle (100) includes at least one in the group of:

- providing (261 ) an indication to a driver of the vehicle (100), the indication requesting a braking according to the braking features to be performed by the driver;

- providing (262) an indication to a driver of the vehicle (100), the indication requesting a braking according to the braking features to be performed by the driver, and, if the driver fails to perform the requested braking, actively controlling (263) at least one braking system (150) to perform the requested braking; and

- actively controlling (264) at least one braking system (150) to perform the requested braking.

12. Computer program comprising instructions which, when the program is executed by a computer, cause the computer to carry out the method (200) according to any one of the claims 1 -1 1.

13. Computer-readable medium comprising instructions which, when executed by a computer, cause the computer to carry out the method (200) according to any one of the claims 1 -1 1.

14. Control unit (160) for a vehicle (100) arranged for transporting one or more passengers (120);

the vehicle (100) including:

the control unit (160) being configured for:

- determining (210), based on information provided by the at least one

- determining (220) a vehicle speed v;

- a point in time tbrake at which a deceleration should be initiated; and - a rate D_rate of the deceleration to be used; and

15. Vehicle including a control unit (160) according to claim 14.