SE2051452A1

SE2051452A1 - Automatic emergency stop method for a vehicle

Info

Publication number: SE2051452A1
Application number: SE2051452A
Authority: SE
Inventors: André Claesson; Björn Kopp; Robert Sjödin
Original assignee: Scania Cv Ab
Priority date: 2020-12-14
Filing date: 2020-12-14
Publication date: 2022-06-15
Also published as: DE112021005877T5; WO2022131992A1; SE545082C2; CN116390878A

Abstract

The present disclosure relates to techniques in the context of vehicles, and more specifically to an automatic emergency stop method for a vehicle. According to a first aspect, the disclosure relates to an automatic emergency stop method comprising obtaining a current position and characteristics of the vehicle, and upon detecting an emergency stop trigger event, determining a stop position, based on the obtained current position and characteristics of the vehicle. The method further comprises controlling one or more of the power consuming components to consume power corresponding to a braking power required to brake the vehicle to stop at the determined stop position, and operating the vehicle to stop at the determined stop position by operating the electrical motor reversely while supplying at least a part of the generated power to the controlled power consuming components. The disclosure also relates to a control arrangement configured to perform the method, to a vehicle comprising the control arrangement, to a computer program and to a computer-readable medium.

Description

Automatic emergency stop method for a vehicle Technical field The present disclosure relates to techniques in the context of vehicles, and morespecifically to an automatic emergency stop method for a vehicle. The disclosurealso relates to a control arrangement configured to perform the method, to a vehiclecomprising the control arrangement, to a computer program and to a computer- readable medium.

Background Energy for propelling electrical vehicles may be stored in special batteries configured to provide a high systern voltage, eg. 65% volt. When deceleratlng avehicle with the electric motor operating reversely as a generator, excess energy istyfpically used to charge the battery. To he able to decelerate the vehicle virith theelectric motor(s) when the energy storage is full, or when the electric motor ishrolten, some vehicles are equipped with a hralte resistor that can take care otexcess energy during regenerative hralting when the energy storage cannot receive more energy. llowever, some vehicles have no hralte resistor as there is no need for onedepending on the vehicles intended operation. This rnay cause problems if there isa tault in the hattery (eg. it the hattery contactors open due to a tault), which meansthat the hralte energy generated when hraltihg the vehicle with the electricalmotor(s) has nowhere to go. ln such a scenario other service hrakes are usuallyavailable to decelerate the vehicle. But lt these service hrakes rely on powerdelivered hy the faulty battery, there is a rislt that these will not tvorlt. l-lence, asituation may occur when lt is hot possible to oral-te the vehicle, which may hedevastating in an emergency situation.

Summarylt is an object of the disclosure to provide a solution that enables emergency stopping of a vehicle using the electrical motor(s) also in situations when there is atault in the hattery (herein reterred to as the energy storage) and there is no hrake 2 rasister vxfith enough capacity to receive the excess energy. it is a further object toprovide a nwethod to step the vehicle En a controlled way without drašning the battery or causing damage to components of the vehicle.

According to a first aspect, the disclosure relates to an automatic emergency stopmethod for a vehicle comprising a plurality of power consuming components andan electrical motor configured to propel the vehicle and to brake the vehicle whenreversely operated. The method comprises obtaining a current position andcharacteristics of the vehicle, and upon detecting an emergency stop trigger event,determining a stop position, based on the obtained current position andcharacteristics of the vehicle. The method further comprises controlling one ormore of the power consuming components to consume power corresponding to abraking power required to brake the vehicle to stop at the determined stop position,and operating the vehicle to stop at the determined stop position by operating theelectrical motor reversely while supplying at least a part of the generated power tothe controlled power consuming components. By the proposed method, the vehiclecan be stopped using only the electrical motor, as power consuming componentsare controlled to take care of excess energy. ln this way it is possible to emergency stop the vehicle also when the battery is full or faulty. ln some embodiments, the controlling comprises activating different numbers of thepower consuming components based on the braking power required to brake thevehicle at the determined stop position. Thereby, the braking power is adjusted based on demand. ln some embodiments, the controlling comprises controlling certain types of powerconsuming components to consume power, based on the braking power requiredto brake the vehicle at the determined stop position. This is another way of adjusting the braking power based on demand. ln some embodiments, the controlling comprises controlling the power consuming components to consume different amounts of power, based on the braking power 3 required to brake the vehicle at the determined stop position. ln this way wear and/or damage caused by the controlling can be avoided when possible. ln some embodiments, the method comprises adapting the controlling along abraking distance until the vehicle stands still. By continually controlling the powerconsuming components along the braking distance, a desirable braking process may be achieved, which considers e.g. passenger comfort or goods. ln some embodiments, the adapting is based on individual properties of the powerconsuming components. By considering power characteristics of individual powerconsuming components in the controlling, the generated braking power can be controlled with good accuracy. ln some embodiments, the adapting is based on variations along the brakingdistance in a braking power required at different positions. Hence, braking powercan be adapted to achieve a smooth braking, as braking power may for example be increased in a downhill slope. ln some embodiments, the emergency stop trigger event comprises one or moreof: a failure at an energy storage, a failure in a braking system of the vehicleseparate from the electrical motor, request for an emergency brake when an energystorage is fully loaded. Hence, an emergency stop may be triggered when any ofthese events occur. ln some embodiments, the power consuming components comprises one or moreof; an A / C converter, an interior heating element, a window heater, a pump, a fan,interior and/or exterior lighting circuit and a gearing component. Hence, differenttypes of power consuming components may be activated to take care of excessenergy generated during the emergency stop. ln some embodiments, the obtaining comprises obtaining the current position andcharacteristics from a vehicle automation system configured to autonomouslyoperate the vehicle. lf the vehicle is operated by a vehicle automation system, the 4 same can typically provide all information required to stop the vehicle using the proposed method. ln some embodiments, the determining is based on geographic data. Hence, if mapinformation is available this can be used to determine a suitable stop position, e.g.a parking spot. ln some embodiments, the obtained Characteristics comprises one or more of,vehicle speed, vehicle velocity, vehicle acceleration, vehicle weight, vehicle load.Hence, any available parameter related to the braking properties can be used to determine a braking power.

According to a second aspect, the disclosure relates to a computer programcomprising instructions which, when the program is executed by a computer, causethe computer to carry out the method according to the third aspect.

According to a third aspect, the disclosure relates to a computer-readable mediumcomprising instructions which, when executed by a computer, cause the computer to carry out the method according to the third aspect.

According to a fourth aspect, the disclosure relates to a control arrangement for usein a vehicle comprising a plurality of power consuming components and an electricalmotor configured to propel the vehicle and to brake the vehicle when reverselyoperated. The control arrangement is configured to perform the method according to any one of the embodiments according to the first aspect.

According to a fifth aspect, the disclosure relates to a vehicle comprising a pluralityof power consuming components, an electrical motor configured to propel thevehicle and to brake the vehicle when reversely operated, and the control arrangement according to the fourth aspect.

Brief description of the drawinqs Fig. 1a illustrates an autonomous vehicle assembled from a set of modules wherethe proposed technique is implemented.

Fig. 1b illustrates a truck where the proposed technique is implemented.

Fig. 2 is a flow chart of an automatic emergency stop method according to the firstaspect.

Fig. 3 illustrates example power consumption ofdifferent power consuming devices.Fig. 4 illustrates a control arrangement according to the fourth aspect in more detail.Fig. 5 illustrates how an emergency stop may be performed with the proposed technique.

Detailed descriptionThis disclosure proposes that one or more power consumers of a vehicle are controlled in order to be able to emergency stop the vehicle with the electric motorwhen the energy storage is full or when there is something wrong with it. Forexample, large power consumers like heaters and air condition units may be used.These large power consumers will then act together as a "brake resistor" and takecare of power generated when operating the electrical motor reversely as agenerator. ln this way it is possible to stop the vehicle in an emergency situationwhen the battery is full or faulty, even if the service brakes (electric brakes) do notwork for any reason, e.g. due to an electrical fault. The proposed technique will now be explained with reference to Figs. 1 to 4.

Fig. "la illustrates ari auteneinetis vehicle 'i asseineled by meduies, where theprepesed technique may be implemented. The iliustrated vehicle l is assembled hytwo drive rnedules 3G and ene functional module 4G. By combining drive inedules3G and iunetienal rncdules 4G in dther ways different types ei vehicles l dan beachieved. Some vehicies l require tvvo er mere drive inodules 3G and somevehicles i enly require ene drive itieciule 3G, ciepending en the structuralcenfiguratidn of the functional module 4G. The drive mddules 3G and functionalmedules 4G comprise a plurality of electrical systems and subsystems. However,for simplicity mainly parts that are associated with the proposed method are shownin Fig. 1a.

The drive module(s)' 30 main function is typically to drive (e.g. propel, steer and brake) a vehicle 1. A drive module 30 comprises a pair of wheels 37 and is 6 configured to be autonomously operated. To enable autonomous operation, thedrive module 30 comprises sensors 13 (only one shown), e.g. Cameras, radars andlidars, for monitoring the surroundings of the vehicle 1. The drive module 30 alsocomprise meters 14 (only one shown) for measuring speed, acceleration,temperature, weight etc. and a positioning circuit 16 (e.g. a GPS device) configuredto determine the position of the drive module 30 and thereby also the position ofthe assembled vehicle 1 _ The drive module 30 may also comprise power consumingcomponents such as fans, pumps etc (not shown).

A functional module 40 is configured to perform a certain function such as to carrya load, e.g. goods or people. Each module 30, 40 in the set of modules comprisesat least one interface releasably connectable to a corresponding interface ofanother module 30,40. ln this example embodiment, each drive module 30 comprises one electric motor11 connected to the wheels 37. The electric motor 11 may also work as a generatorthat generates electric energy while braking the wheels 37. Thus, the propulsionsystem is typically the primary braking system of the vehicle 1. The illuslrateclautonomous moduler vehicle is an example of a vehicle 1 that doesnt necessarilyhave a brake resistor, as it is typically powered by an energy storage (e.g. a battery)that is large enough to receive all the energy that the electric motor 11 generateswhen it brakes. A brake resistor is typically large, heavy, complicated to connect tothe cooling water circuit, requires electronics, fans, etc. Hence, it may beadvantages to omit the braking resistor if it is normally not used. After all, all the energy absorbed by the brake resistor is always a pure loss.

Because the braking funclienallty system may ln seme elluatlcns be lneuiflclerit erfail for some reason, an auxillary braking system (net shown) is typically alsoimplemented. The auxillary braking system comprises for example standard discbrakes and elecfromechanical actuafors that require reliable power suppiy. ln some embodiments the drive module 30 comprises at least one energy storage(not shown) for providing the propulsion system with energy. The energy storage is 7 for example a battery that may be recharged with electric energy. The energystorage may be of limited size and insufficient to supply power to the propulsionsystem and receive power from the braking system while operating the vehicle 1.Hence, in some embodiments the energy storage in the drive module 30 is mainlyused while assembling the vehicle 1 and/or transporting the drive module 30 without load.

The control arrangement 10 of the drive module 30 is configured to operate thedrive module 30 as an independently driven unit. Thus, the control arrangement 10is configured to drive, reverse, brake and stop the vehicle 1. Thus, the drive module30 may transport itself without any externally driven unit such as a towing vehicle.The assembled vehicle 1 is operated by the control arrangements 10 of the twodrive modules 30 in cooperation (e.g. in a master slave configuration). The drivemodules 30 are configured to be autonomously operated by a vehicle automationsystem that assigns missions. The vehicle automation system controls all functionsof the assembled vehicle 1 based on vehicle data provided by the sensors 13 andmeters 14. ln other words, the vehicle automation system may control assembly ofthe vehicle 1 and may after assembly control the vehicle 1 to perform missions (e.g.transport of goods or people), without any driver being present. The vehicleautomation system may be implemented on-board (in one of the controlarrangements 10) or off-board or by a combined solution where some parts areimplemented off-board and the rest on-board. The control arrangement 10 is described in further detail below, with reference to Fig. 4. ln this example embodiment, the functional module 40 needs to be connected to atleast one drive module 30 to be able to move. The functional module 40 maycomprise a space 41 for accommodating or supporting a load. The at least onefunctional module 40 may be configured for transporting goods and may thusfunction as a truck when being assembled with at least one drive module 30. Powerconsuming components 2 (in Fig. 1a denoted 2a, 2b, 2c) such as a fan 2a, a heatingelement 2b and an air condition unit 2c may be located in the space 41. The functional rfiocluie 40 also compriaes an energy storage 12 (typšcally a battery). 8 Even though a connected drive modtiie 3G might aiso comprise an energy storageit may not ioe iarge enough energy to propei and hirake the entire vehicie t duringiiorrnai operation. t-ience, tvhen operating the vehicie i, the energy storage 12 ofthe ftinotionei inodtiie 4G typioaiiy suppiies power to the drive rnoduies 3% whendriving and receives power virhen braking the vehioie 1. The energy storage 12 istyoicaiiy aiso used to power the povver consiiming components 2. in this exampiethe power consuming components 2 ere connected to the sente tDC-circtiit as theeiectrioai inotor "ii and the energy storage 12. Controiiabie svvitches 15 areerranged such that the controi arrengement tt) oi the drive moduie 3G candisconnect one or more ot the power' consuming components 2 or the energy storage trorn the üßcirotiit. it the energy storage 12, or an interface of the energy storage, is broken or faulty,the main braking system of the assembled vehicle 1 will stop working, as powergenerated by the electrical motor 11 when operated reversely as a generator hasnowhere to go. ln addition, the auxiliary brakes may fail as they are dependent onpower supply from the energy storage 12. ln such a situation an emergency stopmethod is needed.

Fig. ih iiitistretes another vehicie i, more specificeiiy an eiectricaiiy driven truck,virhere the proposed technique may aiso he impiemented. The vehicie ot iïig to ise manuaiiy operated vehicie 1 cornprising e driver assistance system that aseists adriver in for exarnpie driving and parking. in some einhodirnents, the vehicie i isconfigured to he operated in an atitonornoiis mode, where the vehicie can itseif(e.g. under driver supervision) perform aii driving tasi-ts and nionitor the drivingenvironment. The vehicle 1 comprises a plurality of electrical systems andsubsystems. However, for simplicity only some parts of the vehicle 1 that areassociated with the proposed method are shown in Fig. 1b. Thus, the iiiustratedvehicie t ot Fig. to comprises an energy storage 12, an eiectricai :notor tt, apiuraiity ot power consdming components 2a-2h and a controi arrangement "iti inaddition, the vehicle 1 comprises sensors 13 (only one shown) e.g. cameras, radars and lidars for monitoring its surroundings. The vehicle 1 also comprises meters 14 9 (only one shown) for measuring speed, acceleration, temperature, weight etc. anda positioning circuit (e.g. a GPS device) configured to determine the position of thevehicle 1.

The eiectršcat ntotez' 11 is configured to propei the vehäcte 1 using energy frem theenergy storage and to brake the vehšcte 1 when ret/ereely operated. En actdštien, thevehicte cemprises auxiliary brakes e.g. disc: er drum brakes (net shown), that may rety on etectršcal power supply.

The vehicle 1 also comprises a plurality of power consuming components 2 (twoshown). The power consuming components are for example one or more of; an aircondition unit, an interior heating element, a window heater, a pump, a fan, interiorand/or exterior lighting circuit, a levelling system and a gearing component. ln theillustrated embodiment, the power consuming components 2 are powered by theenergy storage 12 and/or directly by energy generated by the electric motor 11when reservedly operated. ln some embodiments, the vehicle comprisescontrollable switched arranged to disconnect the energy storage 12 or the powerconsuming components 2 from the electrical motor in the same way as in Fig.1a(not shown).

The control arrangement 10 is configured to receive data from the sensors 13,meters 14 and positioning device 16. ln some embodiments, the controlarrangement 10 is configured to provide driving assistance information to a driverof the vehicle. ln some embodiments, the control arrangement 10 is configured tocontrol operation of the vehicle 1 in at least certain situations, e.g. the controlarrangement 10 may implement an emergency stop function or a vehicleautomation system. The control arrangement is also configured to control operationof the power consuming components 2. The control arrangement 10 is described in further detail below with reference to Fig. 4.

The auxitšery brakes are typically used (sometimes in combination with the electricmotor brake) to brake the vehicle 1 in an emergency situation. lf the auxiliary brakesfail it is possible to brake the vehicle 1 using only the electrical motor. However, if lO the energy storage 12 is full, or if the energy storage 12 (or an interface of theenergy storage) is broken or faulty, the power generated by the electrical motor 11when operated reversely as a generator has to go somewhere else in order toprovide the braking power required to stop the vehicle 1. Eveh lf the vehicle of Fig."lb would celrlprlse a brake resleter, the brake resleter may het be iarge eneugh totake care of alá power that vtfouåd be generated tfvheh emergency etepplhg thevehicle 1, tlslhg ehiy the electrical meter 11. ln such a situation an alternativeemergency stop method is also needed.

To avoid situations where the vehicles of Fig. 1a and Fig. 1b cannot be braked orstopped, this disclosure proposes an automatic emergency stop method wherebraking torque is generated by activating power consuming components. Themethod is for use in situations when an emergency stop is required. For example,it is for use when a main braking system of the vehicle 1 is not fully operable, e.g.because the energy storage is full or broken and when auxiliary brakes do notfunction properly.

Fig. 2 illustrates the proposed automatic emergency stop method for a vehicle 1comprising a plurality of power consuming components 2 and an electrical motor11 configured to propel the vehicle 1 and to brake the vehicle 1 when reverselyoperated. ln some embodiments, the power consuming components comprises oneor more of; an A / C converter, an interior heating element, a window heater, apump, a fan, interior and/or exterior lighting circuit, a levelling system, and a gearing component.

The method may be implemented as a computer program comprising instructionswhich, when the program is executed by a computer (e.g. a processor in the controlarrangement 10 (Fig. 4)), cause the computer to carry out the method. Accordingto some embodiments the computer program is stored in a computer-readablemedium (e.g. a memory or a compact disc) that comprises instructions which, whenexecuted by a computer, cause the computer to carry out the method. ln someembodiments, the method is implemented in a control arrangement 10 of a vehicle, e.g. in the vehicle of Fig. 1a or 1b. ln some embodiments, the method is at least ll partly implemented off-board in a remote vehicle automation system. The methodcan be performed any time during driving when an emergency stop is needed. Themethod may be performed during autonomous operation, or alternatively during manual operation.

The proposed concept is based on the insight that most vehicles today (or theirautomation systems), have at least some knowledge about their surroundings aswell as about vehicle characteristics such as load and speed.

This information can be utilized when emergency braking the vehicle. Thus, theproposed method comprises obtaining S1 a current position and characteristics ofthe vehicle 1. The obtained characteristics refers to any vehicle properties thatinfluence braking behavior. ln some embodiments the characteristics of the vehicleare vehicle properties that influence a braking power required to stop the vehicle.The obtained characteristics comprises for example vehicle speed, vehicle velocity, vehicle acceleration, vehicle weight, vehicle load. ln some embodiments, the characteristics of the vehicle are obtained from one ormore sensors 13 and/or meters 14 in the vehicle. ln some embodiments, the vehicleposition is obtained from a positioning device 16 of the vehicle. ln practice, theposition and/or the characteristics of the vehicle may be obtained in any other suitable way. ln some embodiments, the vehicle 1 is autonomous as the vehicle of Fig. 1a. lnsome embodiments, the vehicle 1 has an autonomous mode where the driver hastransferred the ability to drive to a vehicle automation system that controls allfunctions (even though the driver may be alert and ready to take action at anymoment). lf the vehicle is at least partly autonomously operated, a vehicleautomation system handles monitoring of vehicle and its surroundings and couldtherefore typically directly provide all information relevant to stop the vehicle. lnother words, in some embodiments, the obtaining S1 comprises obtaining thecurrent position and characteristics from a vehicle automation system configured toautonomously operate the vehicle. 12 Sometimes the vehicles (or the vehicle automation system) also has more or lesscontinual access to map data or geographical data, which is for example retrievedfrom a geographical database. The geographical data may be two-dimensional orthree-dimensional. Geographical data can provide information about e.g. routes,slopes, obstacles, parking spaces etc. ln other words, in some embodiments themethod comprises the step of obtaining S0 geographical data. This step can beperformed continually, before and/or after step S1.

An emergency stop is typically triggered by certain emergency stop trigger events.For example, the emergency stop trigger event comprises that the energy storage12 is faulty or that any other serious incident (e.g. overheating) is detected. Hence,in some embodiments, the method comprises detecting S2 an emergency stoptrigger event. The emergency stop trigger event comprises for example a failure atan energy storage, a failure in a braking system of the vehicle separate from theelectrical motor, or a request for an emergency brake when an energy storage isfully loaded. ln some embodiments, the emergency stop is triggered by an"emergency shut down" request. ln the vehicle 1 of Fig. 1a, an "emergency shutdown" is an emergency stop trigger event that may be activated by a passenger orby an off-board operator. ln the vehicle 1 of Fig. 1b, an emergency stop triggerevent may be that the driver pushes an "emergency stop button" (or the brakepedal) or that an obstacle (e.g. a person) is detected in front of the vehicle. ln someembodiments, the proposed emergency stop method is triggered when other service brakes e.g. disc brakes are dysfunctional.

A vehicle 1 that has obtained its current position and vehicle characteristics (andpossibly also map data) has enough information required to determine (or at leastestimate) a suitable place to emergency stop, herein referred to as a stop position.The stop position depends on how urgent the stop is and also on an estimatedbraking distance. The braking distance is typically dependent on vehiclecharacteristics such as vehicle speed, load, and available braking power. Even ifall these parameters are not known, it is still possible to estimate a stop position based on what is known. Stated differently, the method further comprises 13 determining S3 a stop position, based on the obtained current position andcharacteristics of the vehicle, upon detecting S2 an emergency stop trigger event.lt must be appreciated that the determination of the stop position may be either verysophisticated or very simple. ln a very simple implementation, the stop position maybe determined to be a position 10 meters right ahead of the vehicle. This isapplicable for example in a scenario where an object is detected in front of thevehicle and 10 meters is an estimated stopping distance, based on current load andspeed.

Alternatively, the stop position may be a specific position e.g. on a map. Forexample, the stop position is a parking space. This kind of determination is typicallyapplicable in a fully autonomous vehicle, where the vehicle automation system alsohas access to geographic data. The vehicle (or the vehicle automation system) maythen, while also considering the urgency of the stop, determine a suitable place forthe vehicle to stop. ln other words, in some embodiments, the determining S3 of astop position is also based on geographic data.

From the vehicle characteristics and the stop position it possible to estimate abraking power required to stop the vehicle 1 at the stop position. For example, thevehicle 1, i.e. the control arrangement, knows vehicle characteristics such as theinstantaneous vehicle weight, the slope of the road and the stopping distance. lnother words, the method typically comprises determining S4 a braking powerrequired to stop the vehicle at the determined stop position.

An amount of energy that will be generated along a breaking distance up to the stopposition while braking the vehicle using the electrical motor 11 corresponds to thedetermined braking power. The proposed technique involves using the one or moreof the power consuming components 2 to take care of this energy. Hence, themethod further comprises controlling S5 the one or more of the power consumingcomponents 2 to consume power corresponding to a braking power required tobrake the vehicle 1 to stop at the determined stop position. The controlling is forexample done by sending control data to the power consuming components 2. For example, control data causes the power consuming components 2 to be activated. 14 The control data may also control the power consuming components 2 to consumedifferent amount of power. This may for example be done by changing a speed ofa pump or a temperature of a heater. ln some embodiments, the controlling S5comprises controlling the electrical switches 15 to disconnect the energy storage12 from the electrical motor 11. ln this way generated electricity can be sent directly to the consumers and is not affected by limitations in the energy storage 12.

The vehicle 1 can then be stopped by operating the electrical motor 11 as agenerator and feeding the generated power directly to the power consumingcomponents. ln other words, the method then comprises operating S6 the vehicleto stop at the determined stop position by operating the electrical motor 11 reverselywhile supplying at least a part of the generated power to the controlled powerconsuming components 2. This may be done by disconnecting the energy storageand supplying the power directly to the power consuming components 2. Stateddifferently, in some embodiments, the power is supplied directly to the powerconsuming components. ln some embodiments, all the generated energy issupplied to the power consuming components 2. However, in some embodiments,a part of the generated power may be absorbed by a brake resistor (if present) or fed to the energy storage 12 (if it can receive any power). lf the braking distance is short and the vehicle speed is high the required brakingpower may be very high. Then it may be required to activate all the powerconsuming components 2 immediately. However, in other scenarios it might beenough to activate only a few of them. ln other words, in some embodiments thecontrolling S5 comprises activating different numbers (i.e. different counts) of thepower consuming components 2 based on the braking power required to brake thevehicle at the determined stop position and information defining the braking power absorbable by the individual components.

The controlling may also involve controlling operation of the power consumingcomponents 2. For example, a heater or pump may be controlled to operate atmaximum effect or speed if a very large braking power is required to stop the vehicle. Note that this may imply that the components are performing an action that is not at all needed, or that may cause wear or even damage in the component.However, the damage caused if the vehicle 1 is not stopped may in some situationsbe even worse. Hence, it may be preferred that a power consuming component hasto be replaced if the alternative is a serious accident. Stated differently, in someembodiments the controlling S5 comprises controlling the power consumingcomponents 2 to consume different amount of power, based on the braking powerrequired to brake the vehicle 1 at the determined stop position.

As discussed above the vehicle 1 may comprise power consuming components 2of different types. The amount of power consumed is typically different for differentcomponents and may also vary over time. Some components are inert and will notstart to consume power until after a certain time. Some components e.g. fans canbe caused to consume more power if they are controlled not to have a constantspeed, but to instead have a pulsed speed. Fig. 3 illustrate power consumption ofa compressor (left), a light bulb (middle) and a heater (right). By activating thecomponents 2 in different combinations, and at different times, an instantaneousamount of power (that corresponds to a desired braking power) is consumed. lnother words, in some embodiments, the adapting S5a is based on individualproperties of the power consuming components 2. ln some embodiments, thecontrolling S5 comprises controlling certain types of power consuming components2 to consume power, based on the braking power required to brake the vehicle 1 atthe determined stop position. ln this way the consumed power can be adjusted tofor example enable a fast braking or match a smooth braking process where brakingpower is evenly distributed along the stop distance. lf it is desirable to brake as fast as possible, it would typically be desirable to activateall power consuming components 2 at maximum power at once. However, for amore controlled emergency stop, it may be better to distribute braking power alongthe braking distance up to the stop position. Hence, in some embodiments thecontrolling is performed such that the braking power is adjusted at individual pointsin time during the deceleration. ln practice, this means that the control parameters used to control the power consuming components 2 are repeatedly or continually 16 reconfigured along the road. ln other words, in some embodiments, the methodcomprises adapting S5a the controlling S5 along a braking distance until the vehiclestands still. For example, more and more components are activated until the vehiclestands still. ln some embodiments, the adapting S5a is based on variations along the brakingdistance in a braking power required at different positions. For example, additionalcomponents are activated if there is a downhill slope.

Now turning to Fig. 4 which illustrates the control arrangement 10 configured toimplement the proposed emergency stop method of Fig. 2 in more detail. ln someembodiments, the control arrangement 10 is a "unit" in a functional sense. Hence,in some embodiments the control arrangement 10 is a control arrangement comprising several physical control arrangements that operate in corporation.

The control arrangement 10 comprises one or more ECUs. An ECU is basically adigital computer that controls one or more electrical systems (or electrical subsystems) of the vehicle 1 based on e.g. information read from sensors 13 andmeters 14 placed at various parts and in different components of the vehicle 1. ECUis a generic term that is used in automotive electronics for any embedded systemthat controls one or more functions of the electrical system or sub systems in atransport vehicle. The vehicle 1 typically comprises a plurality of ECUs thatcommunicate over a Controller Area Network, CAN, which in the future might bereplaced by for example ethernet based solutions. ln some embodiments, at leastsome parts of the control arrangement 10 are implemented off-board e.g. by anexternal system 20.

The control arrangement 10, or more specifically the processor 101 of the controlarrangement 10, is configured to cause the control arrangement 10 to perform allaspects of the method described above and below. This is typically done by runningcomputer program code stored in the data storage or memory 102 in the processor101 of the control arrangement 10. The data storage 102 may also be configuredto store semi-static vehicle parameters such as vehicle dimensions. 17 The control arrangement 10 may also comprise a communication interface (notshown) for communicating with other control units of the vehicle and/or with external systems 20.

More specifically the control arrangement is configured to obtain a current positionand characteristics of the vehicle. ln some embodiments, the control arrangement 10 is configured to upon detectingan emergency stop trigger event, determine a stop position, based on the obtainedcurrent position and characteristics of the vehicle 1, ln some embodiments, the control arrangement 10 is configured to control one ormore of the power consuming components 2 to consume power corresponding toa braking power required to brake the vehicle 1 to stop at the determined stopposition, and to operate the vehicle 1 to stop at the determined stop position byoperating the electrical motor 11 reversely while supplying at least a part of the generated power to the controlled power consuming components 2.

Fig. 5 illustrate how an emergency stop may be performed with the proposedtechnique. Fig. 5 illustrates a vehicle 1 driving on a road 3. A plurality of othervehicles 1' are also driving on the road 3. ln this example, faults on energy bearings and electric brakes are detected by thevehicle 1. The faults may e.g. be missing data communication, error messages, etc.An emergency stop is then activated (step S2 of Fig. 2) by the vehicle 1. lt can bedone by the vehicle itself or by a driver/operator). The vehicle 1 (or an off boardsystem 20) calculates (step S3 of Fig. 2) a suitable place to stop using dataavailable in the vehicle e.g. provided by sensors 13 and meters 14 in the vehicle 1in combination with information from a control tower (off board) that has detailedinformation about the vehicle's location and surroundings. For example, a parkingspot 4 located 150 m ahead is considered a suitable place to a stop. Based on thecalculated suitable stopping place, the desired braking effect is calculated (step S4of Fig. 2). This is possible as the vehicle 1 knows the instantaneous vehicle weight,the slope of the road (e.g. 3 % uphill) and the stopping distance 5 (150m). One / 18 several power consuming components 2 are then activated (step S5 of Fig. 2)depending on the braking power requirement (e.g. all interior lighting is switchedon, full A/C and/or heating is activated, etc.). The propulsion motors can now beused for deceleration (step S6 of Fig. 2) with the same power that the power consumers momentarily manage to get rid of.

The terminology used in the description of the embodiments as illustrated in theaccompanying drawings is not intended to be limiting of the described method,control arrangement or computer program. Various changes, substitutions and/oralterations may be made, without departing from disclosure embodiments as defined by the appended claims.

The term "or" as used herein, is to be interpreted as a mathematical OR, i.e., as aninclusive disjunction; not as a mathematical exclusive OR (XOR), unless expresslystated otherwise. ln addition, the singular forms "a", "an" and "the" are to beinterpreted as "at least one", thus also possibly comprising a plurality of entities ofthe same kind, unless expressly stated otherwise. lt will be further understood thatthe terms "includes", "comprises", "including" and/ or "comprising", specifies thepresence of stated features, actions, integers, steps, operations, elements, and/ orcomponents, but do not preclude the presence or addition of one or more otherfeatures, actions, integers, steps, operations, elements, components, and/ orgroups thereof. A single unit such as e.g. a processor may fulfil the functions of several items recited in the claims.

Claims

1.

1. CLAIMS An automatic emergency stop method for a vehicle (1) comprising a plurality of power consuming components (2) and an electrical motor (11)configured to propel the vehicle (1) and to brake the vehicle (1) whenreversely operated thus acting as a generator, the method comprising: - obtaining (S1) a current position and characteristics of the vehicle (1 ), - upon detecting (S2) an emergency stop trigger event, determining (S3)a stop position, based on the obtained current position andcharacteristics of the vehicle, - controlling (S5) one or more of the power consuming components (2) toconsume power corresponding to a braking power required to stop thevehicle (1) to stop at the determined stop position, and - operating (S6) the vehicle to stop at the determined stop position byoperating the electrical motor (11) reversely while supplying at least apart of the generated power to the controlled power consumingcomponents (2). _ The method according to claim 1, wherein the controlling (S5) comprises activating different numbers of the power consuming components (2)based on the braking power required to stop the vehicle at the determinedstop position. _ The method according to claims 1 or 2, wherein the controlling (S5) comprises controlling certain types of power consuming components (2) toconsume power, based on the braking power required to stop the vehicle(1) at the determined stop position. _ The method according to any of the preceding claims, wherein the controlling (S5) comprises controlling the power consuming components(2) to consume different numbers of power, based on the braking powerrequired to stop the vehicle (1) at the determined stop position. _ The method according to any of the preceding claims, comprising adapting (S5a) the controlling (S5) along a braking distance until the vehicle standsstill. _ The method according to claim 5, wherein the adapting (S5a) is based on individual properties of the power consuming components (2). _ The method according to claim 5 or 6, wherein the adapting (S5a) is based on variations along the braking distance in a braking power required at different positions. _ The method according to any of the preceding claims, wherein the emergency stop trigger event comprises one or more of: a failure at anenergy storage, a failure in a braking 2 of the vehicle separate from theelectrical motor, request for an emergency stop when an energy storage isfully loaded. _ The method according to any of the preceding claims, wherein the power consuming components comprises one or more of; an air conditioningaggregate, an interior heating element, a window heater, a pump, a fan, interior and/or exterior lighting circuit and a gearing component. 10_The method according to any of the preceding claims, wherein the obtaining (S1) comprises obtaining the current position and characteristicsfrom a vehicle automation system configured to autonomously operate thevehicle. 11_The method according to any of the preceding claims, wherein the determining (S3) is based on characteristics of the environment of thevehicle.12.The method according to any of the preceding claims, where the obtainedCharacteristics comprises one or more of; vehicle speed, vehicle velocity, vehicle acceleration, vehicle weight, vehicle load. 13.The method according to any of the preceding claims comprising: - detecting (S2) an emergency stop trigger event. 14.The method according to any of the preceding claims comprising:- determining (S4) a braking power required to stop the vehicle at the determined stop position. 15.A computer program comprising instructions which, when the program isexecuted by a computer, cause the computer to carry out the method of any one of the claims 1 to16.A computer-readable storage medium comprising instructions which, whenexecuted by a computer, cause the computer to carry out the method of any one of the claims 1 to17.A control arrangement (10) configured to emergency stop a vehiclecomprising a plurality of power consuming components and an electricalmotor configured to propel the vehicle and to brake the vehicle (1) whenreversely operated, wherein the control arrangement (10) is configured to: o obtain a current position and characteristics of the vehicle, o upon detecting (S2) an emergency stop trigger event, determinea stop position, based on the obtained current position andcharacteristics of the vehicle (1 ), o control one or more of the power consuming components (2) toconsume power corresponding to a braking power required tostop the vehicle (1) to stop at the determined stop position, and o operate the vehicle (1) to stop at the determined stop position by operating the electrical motor (11) reversely while supplying atleast a part of the generated power to the controlled power consuming components (2). 18.The control arrangement (10) according to claim 17, wherein the controlarrangement is configured to perform the method according to any one of claims 2 to19.A vehicle (1) comprising: - a plurality of power consuming components (2) - an electrical motor (11) configured to propel the vehicle (1) and tostop the vehicle (1 ) when reversely operated acting as a generator,and - the control arrangement (10) according to claim 17 or 18.