SE543017C2

SE543017C2 - Method and control unit for braking a vehicle

Info

Publication number: SE543017C2
Application number: SE1850090A
Authority: SE
Inventors: André Claesson
Original assignee: Scania Cv Ab
Priority date: 2018-01-26
Filing date: 2018-01-26
Publication date: 2020-09-29
Also published as: SE1850090A1; DE112019000290T5; WO2019147178A1

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

lO METHOD AND CONTROL UNIT FOR BRAKING A VEHICLETechnical field The present invention relates to a vehicle, and in particular to a method and a controlunit for braking a vehicle arranged for transporting one or more passengers. Thepresent invention also relates to a computer program and a computer-readablemedium that implement the method according to the invention.

Background The following background description constitutes a description of the background tothe 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 inareas having traffic lights arranged along the roads or streets for controlling thevehicle traffic flow. ln, for example urban areas, such as in cities, a bus will normallyencounter a number of traffic lights during its route. As is well known, the traffic lightsmay indicate that vehicles are allowed to pass the traffic light, e.g. by displaying agreen color, may indicate that vehicles should be braked and stop, e.g. by displayinga 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 thetraffic lights, e.g. based on the color displayed by the traffic lights. Thus, the driveradapts the driving related actions/maneuvers being performed based on theindications provided by the traffic lights. For example, if an upcoming traffic lightdisplays a green light, the driver may proceed towards, and may pass, the traffic lightwithout performing any additional actions. However, if the upcoming traffic lightdisplays a yellow or red light, the driver will typically brake the vehicle, such that thevehicle speed is reduced, and such that the vehicle is stopped at the traffic light. Thedriver will then have to wait until the traffic light displays a green light again, and may then pass the traffic light. lO Brief description of the invention When approaching a traffic light with a vehicle arranged for transporting one or morepassengers, the driver will have to brake the vehicle if the traffic light changes fromdisplaying a green color, indicating that the vehicle may pass, to displaying a yellowor 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 toaggressively/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 mayeven be dangerous, for the passengers of the vehicle, especially if the passengersare not healthy, are not seated and/or are not properly using safety/seat belts. ln some vehicles, such as for example buses, military vehicles, fire trucks, orambulances, passengers are often not using safety/seat belts. Also, in some of thesevehicles, passengers are often standing, e.g. bus passengers are often standing inthe gangways since there were no available seats for them in crowded buses. Forsuch standing passengers, an aggressive/sharp braking before a traffic light maycause 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, illpassengers and/or disabled passengers, since they may not reach agrip/handle/knob or may not have the strength to hold on to a grip/handle/knob or thelike 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 beextra 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 standingpassengers, 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 lO may thus be forced to perform a number of more or less aggressive/sharp brakingactions, which may be dangerous for the passengers. lt is therefore an objective of the present invention to provide a method and a controlunit for braking a vehicle arranged for transporting one or more passengers such thatthese problems are at least partly solved.

According to an aspect of the present invention, this objective is achieved throughthe above-mentioned method for braking a vehicle arranged for transporting one ormore passengers, the vehicle including: - at least one communication device arranged for communication with at least oneentity external to the vehicle; the method including: - determining, based on information provided by the at least one communicationdevice, a time period tchange until a color of a traffic light ahead of the vehicle willchange; - determining a vehicle speed v; - determining a distance d to a stop position psiop 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 dand the deceleration sensibility Dsense, braking features usable for achieving a vehiclestandstill at the stop position psiop, the braking features including one or more in thegroup of: - a point in time tbrake at which a deceleration should be initiated; and- a rate Dfaie of the deceleration to be used; and - performing at least one action related to braking of the vehicle by usage of thedetermined braking features.

Hereby, a smooth and comfort braking of a vehicle arranged for transporting one ormore passengers may be achieved when the vehicle approaches a traffic lightchanging its displayed color, e.g. from displaying a green color to displaying a yellowor a red color. The braking features may be determined early, before the change indisplayed traffic light color occurs and possibly even before a driver of the vehicle cansee 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 lO requested to start braking the vehicle although the traffic light is still displaying agreen light, if it is determined that the traffic light will change to yellow and/or redbefore the vehicle will have passed the traffic light. Also, the driver may be requestedto start braking the vehicle before the vehicle has advanced enough for the driver tobe able to see the traffic light, if it is determined that the traffic light will change toyellow and/or red before the vehicle will have passed the traffic light.

Thus, due to the gained additional time useable for braking the vehicle, suddenand/or aggressive braking operations may be avoided when the present invention isused, which improves safety and comfort for the passengers, e.g. for passengers notbeing healthy, not being seated and/or not properly using safety/seat belts. Forexample, 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 timeperiod 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 achange 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 timeperiod tchange is performed before the traffic light is visible from the vehicle. Hereby, a smooth and well controlled braking of the vehicle is achievable. lt may thus be possible to determine the time period tchange until a change of the colorof the traffic light before the traffic light is visible from the vehicle, since the timeperiod tchange may be determined at least partly based on information provided byexternal entities, other vehicles and/or on information previously gathered by thevehicle itself. Obviously, the time period tchange may be determined before thedisplayed traffic light color changes; tchange > O. Hereby, a smoother and a lessaggressive braking over a longer time period may be used for braking the vehicle. lO According to an embodiment of the present invention, the determining of the distanced 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 psiop at theupcoming traffic light is provided. Since a number of different types of informationmay be used for the determination, the determination of the distance d to a stopposition psiop may essentially always be reliably and accurately performed. Also, theinformation 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 thedeceleration 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 inurban areas is taken care of. The problem of standing passengers being exposed tounpleasant 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 orthe like in the bus. However, when the embodiment of the present invention is used,standing passengers are specifically taken into account when the braking featuresare determined, which considerably reduces the risk for discomfort of standingpassengers.

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

Hereby, a reliable and accurate determination of the deceleration sensibility Dsense ofthe one or more passengers is provided. lO According to an embodiment of the present invention, the determining of thedeceleration sensibility Dsense of the one or more passengers is based on one or morein 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 thefloor of the vehicle; - curvature information for at least one part of a road section between the vehicle andthe 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 decelerationsensibility Dsense of the one or more passengers, which increases the accuracy andreliability of the determination. Also, one or more of these types of information areusually 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 brakingfeatures is also based on a friction between one or more vehicle tires and at leastone 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, whichincreases the possibility of performing a smooth braking operation which guaranteesthat the vehicle is stopped at the stop position psiop.

According to an embodiment of the present invention, the friction is determinedbased on one or more in the group of: - visual information for at least one part of a road section between the vehicle andthe 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) ofthe vehicle; lO - 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 moredifferent 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 brakingfeatures is performed in relation to the deceleration sensibility Dsense such that a riskfor passenger discomfort is eliminated.

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

According to an embodiment of the present invention, the performing of at least oneaction 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 brakingaccording to the braking features to be performed by the driver; - providing an indication to a driver of the vehicle, the indication requesting a brakingaccording to the braking features to be performed by the driver, and, if the driver failsto perform the requested braking, actively controlling at least one braking system toperform 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 ofwhen it is time to start braking, and/or is provided with an indication of how thebraking is to be performed. For example, a lamp/light may be activated when it istime to start braking, i.e. at the deceleration initiation point in time tbrake, and/or thelamp/light may display various colors indicating if the deceleration rate Draw should bechanged, or if the used deceleration rate Draie is adequate/acceptable. Also, aspeaker may be activated to output a sound/message at the deceleration initiation lO point in time tbrake and/or to output various sounds/messages indicating if thedeceleration rate Draie should be changed, or if the used deceleration rate Dfaie isadequate/acceptabie. However, if the driver fails to follow the instructions/indications,an automatic braking may be performed according to an embodiment, which furtherincreases the probability for a comfortable braking. Also, a completely automaticbraking 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 theabove-mentioned control unit for a vehicle arranged for transporting one or morepassengers. The vehicle includes at least one communication device arranged forcommunication with at least one entity external to the vehicle. The control unit isconfigured for:- determining, based on information provided by the at least one communicationdevice, a time period tchange until a color of a traffic light ahead of the vehicle willchange;- determining a vehicle speed v;- determining a distance d to a stop position psiop 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 dand the deceleration sensibility Dsense, braking features usable for achieving a vehiclestandstill at the stop position psiop, the braking features including one or more in thegroup of: - a point in time tbrake at which a deceleration should be initiated; and - a rate Dfaie 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. lt will be appreciated that all the embodiments described for the method aspect of theinvention are applicable also to the control unit aspect of the invention. Thus, all theembodiments described for the method aspect of the invention may be performed bythe control unit, which may also be a control device, i.e. a device. The control unitand its embodiments have advantages corresponding to the advantages mentioned above for the method and its embodiments. lO According to an aspect of the present invention, a vehicle including a control unit asdescribed herein is presented.

According to an aspect of the present invention, the above-mentioned computerprogram and computer-readable medium are configured to implement the methodand 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 inventionmay 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 hereindescribed embodiments may be implemented.

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

A vehicle 100, as shown schematically in Figures 1, comprises a pair of drive wheels111, 112 and at least one other pair of wheels 113, 114. The vehicle furthermorecomprises a drivetrain configured to transfer a torque between at least one powersource, such as e.g. an engine 101, and the drive wheels 111, 112. The at least one lO lO 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 anoutput shaft 102 of the engine 101, connected to a clutch 106, and via the clutch alsoto a gearbox 103. The torque provided by the engine 101 is provided to an input shaft109 of the gearbox 103. A propeller shaft 107, connected to an output shaft of thegearbox 103, drives the drive wheels 111, 112 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 ofthe wheels of the vehicle. The at least one braking arrangement 151, 152, 153, 154may be included in at least one braking system 150. Braking of the vehicle 100, i.e. aretardation 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 onebraking system 150 may also include one or more additional braking devices 155, forexample 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 theat least one braking arrangement 151, 152, 153, 154 and/or the at least oneadditional 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 seconddetermination unit 162, a third determination unit 163, a fourth determination unit164, a fifth determination unit 165, and an action performing unit 166, as ismentioned below. The control unit/device 160 and/or another control unit/device mayfurther be configured for controlling one or more of the at least one power source101, the clutch 106, the gearbox 103, and/or any other units/devices/entities of thevehicle. 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 forpresenting indications to the driver, such as visual, audio and/or tactile indicationsusing for example lights, sounds and/or vibrations presented in the instrument lO ll Cluster, the on windshield and/or in the driver seat. The at least one indication output175 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 fortransporting one or more passengers 120, according to an embodiment of thepresent invention. The vehicle 100, which includes at least one communicationdevice 170 arranged for communication with at least one entity 190, 180, 181, 185external to the vehicle 100, is illustrated in figures 3 and 4. Figure 3 schematicallyillustrates the vehicle 100 approaching a traffic light 190 and communicating with atleast one external entity 190, 180. Figure 4 schematically illustrates the vehicle 100approaching a traffic light 190 and communicating with at least one other vehicle 185and/or with at least one other external entity 180, 181. Figures 3 and 4 may be usefulfor understanding the embodiments of the present invention described below. lt should be noted that the method steps illustrated in figure 2 and described hereindo not necessarily have to be executed in the order illustrated in figure 2. The stepsmay essentially be executed in any suitable order, as long as the physicalrequirements and the information needed to execute each step is available when the step is executed. ln a first step 210, a time period tchange until a color of a traffic light 190 ahead of thevehicle 100 will change is determined based on information provided by the at leastone communication device 170. For example, the time period tchange until the trafficlight 190 will change/turn from green (G) to yellow (Y), or until the traffic light 190 willchange/turn from yellow (Y) to red (R), is here determined based on informationreceived 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 atleast one communication device 170 is arranged for communicating with the at leastone external entity 180, 181, 185, and may thereby provide the information needed for determining the time period tchange. lO 12 ln a second step 220, a vehicle speed v, at which the vehicle 100 is travelling isdetermined. 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. ln a third step 230, a distance d to a stop position psiop at the upcoming traffic light190 is determined. The stop position psiop may here be located directly at the trafficlight 191, if there is no queue at the traffic light 190, or may be located after one ormore vehicles queueing at the traffic light 190, i.e. before/upstream the traffic light position 191 in the direction of the vehicle movement. ln a fourth step 240, a deceleration sensibility Dsense of the one or more passengers120 is determined. This determination may be performed according to one or more below described embodiments. ln a fifth step 250, braking features usable for achieving a vehicle standstill at thestop position psiop are determined. The braking features include a point in time tbrake atwhich a deceleration/retardation of the vehicle 100 should be initiated and/or a rateDraie of the deceleration to be used, i.e. how aggressive/sharp thedeceleration/retardation should be. The determination of these braking features is described below for various embodiments of the present invention. ln 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 onecommunication device 170 may be essentially any device transferring information toand/or from the vehicle, and the at least one entity 180, 181, 185 external to thevehicle 100 may be essentially any external entity communicating with the at leastone communication device 170 for the transfer of the information to and/or from thevehicle. Thus, the at least one external entity 180, 181, 185 may e.g. be associatedwith, 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 (V2l) communicationdevice, and/or a vehicle-to-everything (V2X) communication device, such that lO 13 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 changingits 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 presentinvention 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 atleast one communication device 170, which is arranged for communication with theat least one external entity 180, 181, 185, e.g. an infrastructure and/or other vehicleentity, the braking features may be determined early. ln some situations, the brakingfeatures may be determined already before a driver of the vehicle can see the trafficlight 190. Thus, features of a controlled braking action may hereby be determinedeven 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 hasbeen possible in conventional solutions. Valuable additional time, which may be usedfor braking the vehicle 100, is hereby gained, which greatly increases the possibilitiesfor smooth braking.

Thus, when the embodiments of the present invention are used, a driver of thevehicle and/or an active braking control system will not be forced to perform suddenand 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 (Fi), since informationrelated to the changes of traffic light colors will always be available in the vehiclebefore the changes occur, and will be usable for initiating the braking and also forproviding a smooth and comfortable braking.

Especially, the safety and comfort for passengers not being healthy, not being seatedand/or not properly using safety/seat belts is hereby improved. For example, the riskfor standing passengers to fall in buses carrying standing passengers is minimized byusage of the embodiments of the present invention. lO 14 According to various embodiments of the present invention, the determination 210 ofthe time period tchange is based on information received from the at least one externalentity 180, 181, 185. The information may here be provided by the traffic light 190itself, e.g. in the form of signals indicating time periods until changes in the displayedtraffic light color. The information may also be provided by a unit 180, 181 associatedwith the upcoming traffic light 190, such as an infrastructure device 180, 181 (V21)having a wired and/or wireless connection to the traffic light 190. For example, theinfrastructure device 180, 181 may include a control unit providing control signals tothe traffic light 190, wherein the control signals may be used for controlling the colordisplayed 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 ofvehicles, such as e.g. buses traveling at least partly the same route, may exchangeinformation related to the traffic lights 190, such as where they are located and howor when they change the displayed color. As is illustrated in figure 4, such informationprovided by at least one other vehicle 185 passing the traffic light 190 before thevehicle 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 previouslygathered 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 eachtraffic light of that route a number of times per day. The buses may then gatherinformation related to a traffic light 190 at least once when they pass it, and may usethis gathered information the next time that traffic light 190 is approached. Asmentioned above, the gathered information may also be provided to other vehicles185. Generally, vehicles may gather, store and/or provide essentially any informationthat may be useful for the vehicle itself and/or for other vehicles. This informationmay be retrieved and/or transmitted immediately when having been gathered and/ormay be retrieved and/or transmitted later, after having been gathered, such that the lO vehicle, or possibly a fleet of vehicles, may use the information. The one or morevehicles 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 bedetermined 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 isaccording to an embodiment, possible to determine 210 the time period tchange beforethe traffic light 190 is visible from the vehicle 100. The point in time tbrake at which thedeceleration should be initiated may hereby be determined to an earlier timeinstance, such that a less aggressive braking over a longer time period may be usedfor braking the vehicle, compared to conventional systems, for which braking mayonly be initiated after the driver has actually seen/observed a change of the displayedtraffic light color.

The distance d to a stop position psiop at the upcoming traffic light 190, as isillustrated in figure 3, may be determined based on various information. Theinformation may for example be related to vehicle positioning information, digital mapinformation, radar-based information and/or camera-based information. Theinformation may be previously gathered by the vehicle 100 and/or may be providedby at least one other vehicle 185. Vehicles may store information themselves and/ormay share information with other vehicles 185, 100, as mentioned above. Also, theinformation may be obtained from traffic systems related to that road section, e.g.infrastructure systems/units/devices 190, 180, 181. The radar and/or cameraequipment providing the radar-based information and/or the camera-basedinformation may be arranged in the vehicle 100, in another vehicle 185, at the trafficlight 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 tothe vehicle 100, may thus be obtained in various ways. For example, it may bedetermined on the basis of map data, e.g. from digital maps in combination withpositioning information, e.g. GPS (global positioning system) information. Thepositioning information may be used to determine the location of the vehicle inrelation to the map data so that the distance d to a stop position psiop at the upcoming lO 16 traffic light 190 may be extracted from the map data. Various present-day cruisecontrol systems use map data and positioning information. Such systems may thenprovide the map data and the positioning information needed for performing theembodiments of the present invention, thereby minimizing the additional complexityinvolved in determining the traffic light related information. By usage of positioninginformation and digital map information, the embodiments of the present inventionmay virtually look ahead along an upcoming road section in order to determineinformation related to upcoming traffic lights, that might even not yet be visible fromthe vehicle.

As mentioned above, standing passengers are especially vulnerable forsharp/aggressive brakes. According to an embodiment of the present invention, thisvulnerability is handled by determining 240 the deceleration sensibility Dsense of theone or more passengers 120 based on if there are standing passengers onboard thevehicle, i.e. the determination 240 of the deceleration sensibility Dsense includesdetermining if at least one passenger 120 is standing. This may be determined in anumber of ways according to various embodiments of the present invention, e.g.based on information provided by at least one monitoring system 130 arranged onboard the vehicle 100. For example, visual information provided by at least onecamera device 130 on board of the vehicle 100 may be used as a basis for thedetermination 240 of the deceleration sensibility Dsense of the one or more passengers120. Also, tactile information provided by at least one pressure sensor device 130arranged e.g. at the floor of the vehicle 100 may be used as basis for thedetermination 240. Some vehicles have wheel chair safety belts, and also indicatorsindicating if one or more wheel chair safety bels are used. Information related tousage of a wheel chair safety belt may then also be used as a basis for thedetermination 240 of the deceleration sensibility Dsense.

Further, the determination 240 may also be based on curvature information for atleast one part of a road section between the vehicle 100 and the traffic light 190. Thecurvature information may be provided by usage of positioning information, e.g. GPS information in combination with map information, as mentioned above. lO 17 Driver input may also be used as a basis for the deceleration sensibility Dsensedetermination 240. For example, if the driver of a bus notices that one or more olderpassengers, possibly using sticks/canes, enters the bus, the driver may inputinformation, by use of essentially any suitable input device, which is interpreted asthere are passengers on board having an increase deceleration sensibility Dsense.

The deceleration sensibility Dsense determination 240 may also be based oninformation previously gathered by the vehicle 100 and/or gathered and provided byat least one other vehicle 185 (V2V). Hereby, a self-learning vehicle is provided,which may be adapted based on essentially any useful information gathered by thevehicle 100 and/or another vehicle 185. Thus, if it over time occurs accidentsinvolving falling passengers at a specific traffic light, the deceleration sensibility Dsensedetermination 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 beinglocated 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 roadsections where buses usually carry many passengers, implying that a bus probablywill carry standing passengers when such traffic lights and/or road sections arepassed. The deceleration sensibility Dsense may also be increased at certain points intime, for example if it has previously been observed that a bus carries manypassengers at those certain points in time, e.g. due to arrival of connecting buses ortrains, 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, thepassengers, the environment in which the vehicle travels, and/or the traffic light maybe used as a basis for determining 240 the deceleration sensibility Dsense. Thedetermination 240 may then include a suitable analysis of the information beinguseful for determining 240 the deceleration sensibility Dsense.

As mentioned above, braking features usable for achieving a vehicle standstill at thestop position psiop are determined 250 according to various embodiments of thepresent invention. The braking features include at least a point in time tbfake at which abraking should be initiated and/or a rate Draie of the deceleration to be used. The braking features may here be determined 250 based at least on the determined lO 18 deceleration sensibility Dsense, e.g. such that a higher deceleration sensibility Dsenseresults in a lower deceleration rate Draie for the braking and/or in an earlier point intime tbrake to start braking. Hereby, i.e. since the determination 250 of the brakingfeatures is performed in relation to the deceleration sensibility Dsense, the risk forpassenger discomfort and/or injury is eliminated, or is at least considerably reduced.ln other words, a higher deceleration sensibility Dsense results in a smootherdeceleration than a lower deceleration sensibility Dsense results in, when thedetermination 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 frictionbetween one or more vehicle tires 111, 112, 113, 114 and at least one part of a roadsection between the vehicle 100 and the traffic light 190. Thus, if there is freezingdegrees and/or are low friction areas 310 on the road ahead, including for examplesnow, ice, water, leaves, oil or some other friction reducing element, the brakingfeatures may be determined 250 such that this is taken into consideration. Forexample, the braking features may then be determined 250 such that the point intime tbrake at which the deceleration should be initiated is earlier, such that the vehicleis stopped without performing any braking/deceleration at the low friction areas 310.Also, the deceleration rate Dfaie may be adapted before and/or after the low frictionareas 310, such that the vehicle is stopped without having to perform anybraking/deceleration at the low friction areas 310.

The friction between one or more vehicle tires 111, 112, 113, 114 and at least onepart of a road section may, according to various embodiments of the invention, bedetermined in a number of ways. For example, the friction determination may bebased on visual information provided by at least one camera device of the vehicle100, at least one camera device of another vehicle 185 and/or at least one cameradevice of an infrastructure device 190, 180, 181. The at least one camera shouldthen be directed towards at least one part of a road section between the vehicle 100and the traffic light 190. Also, the friction determination may be based on ambienttemperature information and/or based on information related to the one or more tires 111, 112, 113, 114 of the vehicle, e.g. if they are summer type tires or winter type lO 19 tires. Also, other indicators of low frictional areas may be utilized in the frictiondetermination, such as an activation of an anti-lock braking system (ABS) of thevehicle 100, whereby a low friction may be determined if the anti-lock braking systemhas been activated.

Generally, the information on which the friction determination is based may begathered/provided by the vehicle itself 100, by another vehicle 185 (V2V) and/or by atleast one infrastructure device 190, 180, 181 (V2l), as is mentioned above for othertypes of information being exchanged between vehicles 100, 185 (V2V) and betweenvehicles 100, 185 and infrastructure devices 190, 180, 181 (V2l).

According to various embodiments of the present invention, the determined brakingfeatures, i.e. the braking initiation point in time tbraiw and the deceleration rate Draw,may be used as a driver support 261, 262 and/or may be used to actually control263, 264 the braking of the braking of the vehicle 100.

As mentioned above, at least one action related to braking of the vehicle 100 isperformed 260 by making use of the determined braking features. The at least oneaction may include providing 261 an indication to a driver of the vehicle 100 by use ofthe at least one indication output 175, the indication requesting the driver to performa braking of the vehicle according to the braking features. The indication may includeessentially anything that may be perceived and/or interpreted by the driver, such asvisual, audio and/or tactile indications using for example lights, sounds and/orvibrations presented in the instrument cluster, on the windshield and/or in the driverseat. Any suitable output 175 may be used for conveying/presenting the indication tothe driver. For example, a lamp/light/display/icon may be activated when it is time tostart braking, i.e. at the deceleration initiation point in time tbraiw. Thelamp/light/display/icon may display various colors, symbols and/or patters indicating ifthe deceleration rate Draw should be changed, or if the used deceleration rate Draw isadequate/acceptable. Also, a speaker may be activated to output a sound/messageat the deceleration initiation point in time tbraiw and/or to output varioussounds/messages indicating if the deceleration rate Draw should be changed, or if theused deceleration rate Draw is adequate/acceptable. Also, a certain vibration may beprovided at the deceleration initiation point in time tbraiw. Various vibrations, e.g. lO various vibration frequencies, may be used for indicating if the deceleration rate Drawshould be increased or decreased.

The at least one performed 260 action may also include first providing 162 the atleast one indication requesting the driver to perform the requested braking, asdescribed above, and then, if the driver fails to perform the requested braking,actively controlling 263 a braking system to perform the requested braking. Thus, ifthe driver does not react to the at least one brake requesting indication, an automaticbraking is activated by controlling the at least one braking system 150. Hereby, it issecured that a braking minimizing passenger discomfort is achieved, also if the driverfails to react on the indication. Also, if the driver does not react to the at least onebrake 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 ormore control systems, without influence of a physical driver, the at least oneperformed 260 action may also include actively controlling 264 the at least onebraking system 150 to perform the requested braking, i.e. according to thedetermined braking features. Also, the speed and/or fuel injection requested by acruise 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 vehiclemay 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 100arranged for transporting one or more passengers 120 is presented. The hereindescribed method and method embodiments may be performed by the control unit160. 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 communicationdevice 170, a time period tchange until a color of a traffic light 190 ahead of the vehicle100 will change; lO 21 - determining 220 a vehicle speed v;- determining 230 a distance d to a stop position psiop at the upcoming traffic light190;- determining 240 a deceleration sensibility Dsense of the one or more passengers120;- determining 250, based on the time period tchange, the vehicle speed v, the distanced and the deceleration sensibility Dsense, braking features usable for achieving avehicle standstill at the stop position psiop, the braking features including one or morein the group of: - a point in time tbrake at which a deceleration should be initiated; and - a rate Dfaie of the deceleration to be used; and- performing (260) at least one action related to braking of the vehicle 100 by usageof the determined braking features.

The control unit 160, e.g. a device or a control device, according to the presentinvention may be arranged for performing all of the above, in the claims, and in theherein described embodiments method steps, e.g. by including the above mentionedcontrol units 161, 162, 163, 164, 165, 166. The control unit 160 is hereby providedwith the above described advantages for each respective embodiment. The presentinvention 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 embodimentsfor braking a vehicle may also be implemented in a computer program, which, when itis executed in a computer, instructs the computer to execute the method. Thecomputer program is usually constituted by a computer program product 503 storedon a non-transitory/non-volatile digital storage medium, in which the computerprogram is incorporated in the computer-readable medium of the computer programproduct. The computer-readable medium comprises a suitable memory, such as, forexample: ROIVI (Read-Only l\/lemory), PROIVI (Programmable Read-Only l\/lemory),EPROIVI (Erasable PRONI), Flash memory, EEPROIVI (Electrically Erasable PRONI),a hard disk unit, etc. lO 22 Figure 5 shows in schematic representation a control unit 500/160, which maycorrespond to or may include one or more of the above-mentioned control units 161,162, 163, 164, 165, 166, i.e. afirst determination unit 161 performing the first methodstep 210, a second determination unit 162 performing the second method step 220, athird determination unit 163 performing the third method step 230, a fourthdetermination unit 164 performing the fourth method step 240, a fifth determinationunit 165 performing the fifth method step 250, and an action performing unit 166performing the sixth method step 260. The control unit 500/160 comprises acomputing unit 501, which can be constituted by essentially any suitable type ofprocessor or microcomputer, for example a circuit for digital signal processing (DigitalSignal Processor, DSP), or a circuit having a predetermined specific function(Application Specific lntegrated Circuit, ASIC). The computing unit 501 is connectedto a memory unit 502 arranged in the control unit 500/160, which memory unitprovides the computing unit 501 with, for example, the stored program code and/orthe stored data which the computing unit 501 requires to be able to performcomputations. The computing unit 501 is also arranged to store partial or final resultsof computations in the memory unit 502. ln addition, the control unit 500/160 is provided with devices 511, 512, 513, 514 forreceiving and transmitting input and output signals. These input and output signalscan contain waveforms, impulses, or other attributes which, by the devices 511, 513for the reception of input signals, can be detected as information and can beconverted into signals which can be processed by the computing unit 501. Thesesignals are then made available to the computing unit 501. The devices 512, 514 forthe transmission of output signals are arranged to convert signals received from thecomputing unit 501 in order to create output signals by, for example, modulating thesignals, 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 outputsignals can be constituted by one or more of a cable; a data bus, such as a CAN bus(Controller Area Network bus), a l\/IOST bus (l\/ledia Orientated Systems Transportbus), or some other bus configuration; or by a wireless connection. A person skilledin the art will appreciate that the above-stated computer can be constituted by the lO 23 computing unit 501 and that the above- stated memory can be constituted by thememory unit 502.

Control systems in modern vehicles commonly comprise communication bus systemsconsisting of one or more communication buses for linking a number of electroniccontrol 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 theresponsibility for a specific function can be divided amongst more than one controlunit. Vehicles of the shown type thus often comprise significantly more control unitsthan are shown in figures 1 and 3-5, which is well known to the person skilled in theart within this technical field. ln a shown embodiment, the present invention may be implemented by the one ormore above mentioned control units 161, 122, 163, 164, 165, 166. The invention canalso, however, be implemented wholly or partially in one or more other control unitsalready present in the vehicle, or in some control unit dedicated to the present invenﬁon.

Here and in this document, units are often described as being arranged forperforming steps of the method according to the invention. This also includes that theunits 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 illustratedas separate units. These units 161, 122, 163, 164, 165, 166 may, however, belogically separated but physically implemented in the same unit, or can be bothlogically and physically arranged together. These units 161, 122, 163, 164, 165, 166may for example correspond to groups of instructions, which can be in the form ofprogramming code, that are input into, and are utilized by a processor/computing unit501 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. lnstead,the present invention relates to, and encompasses all different embodiments beingincluded within the scope of the independent claims.

Claims

lO 24 Claims

1. Method (200) for braking a vehicle (100) arranged for transporting one ormore passengers (120); the vehicle including: - at least one communication device (170) arranged for communication with at leastone entity (190, 180, 181, 185) external to the vehicle (100); the method including: - determining (210), based on information provided by the at least onecommunication 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 psiop 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, thedistance d and the deceleration sensibility Dsense, braking features usable forachieving a vehicle standstill at the stop position psiop, the braking features includingone or more in the group of: - a point in time tbrake at which a deceleration should be initiated; and- a rate Dfaie of the deceleration to be used; and - performing (260) at least one action related to braking of the vehicle (100) by usageof the determined braking features.

2. l\/lethod (200) according to claim 1, wherein the determining (210) of thetime 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. l\/lethod (200) according to any one of claims 1-2, wherein thedetermining (210) of the time period tchange is performed before the traffic light (190) isvisible from the vehicle (100). lO

4. Method (200) according to any one of claims 1-3, wherein thedetermining (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. l\/lethod (200) according to any one of claims 1-4, wherein thedetermining (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. l\/lethod (200) according to any one of claims 1-5, wherein thedetermining (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. l\/lethod (200) according to any one of claims 1-6, wherein thedetermining (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 thevehicle (100); - tactile information provided by at least one pressure sensor device (130) arrangedat 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). lO 26

8. Method (200) according to any one of claims 1-7, wherein thedetermining (250) of the braking features is also based on a friction between one ormore vehicle tires (111, 112, 113, 114) and at least one part of a road sectionbetween the vehicle (100) and the traffic light (190).

9. l\/lethod (200) according to claim 8, wherein the friction is determinedbased 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) ofthe vehicle (100); -information related to the one or more vehicle tires (111, 112, 113, 114); - 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. l\/lethod (200) according to any one of claims 1-9, wherein thedetermining (250) of the braking features is performed in relation to the decelerationsensibility Dsense such that a risk for passenger discomfort is eliminated.

11. l\/lethod (200) according to any one of claims 1-10, wherein theperforming (260) of at least one action related to braking of the vehicle (100) includesat least one in the group of: - providing (261) an indication to a driver of the vehicle (100), the indicationrequesting 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 indicationrequesting 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) atleast one braking system (150) to perform the requested braking; and - actively controlling (264) at least one braking system (150) to perform the requestedbraking. lO 27

12. Computer program comprising instructions which, when the program isexecuted by a computer, cause the computer to carry out the method (200) according to any one of the claims 1-11.

13. Computer-readable medium comprising instructions which, when executedby a computer, cause the computer to carry out the method (200) according to any one of the claims 1-11.

14. Control unit (160) for a vehicle (100) arranged for transporting one ormore passengers (120); the vehicle (100) including: - at least one communication device (170) arranged for communication with at leastone entity (190, 180, 181, 185) external to the vehicle (100); the control unit (160) being configured for: - determining (210), based on information provided by the at least onecommunication 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 psiop 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, thedistance d and the deceleration sensibility Dsense, braking features usable forachieving a vehicle standstill at the stop position psiop, the braking features includingone or more in the group of: - a point in time tbrake at which a deceleration should be initiated; and- a rate Draw of the deceleration to be used; and - performing (260) at least one action related to braking of the vehicle (100) by usageof the determined braking features.

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