WO2015156731A1

WO2015156731A1 - Method, device and system for supporting the formation of platooning

Info

Publication number: WO2015156731A1
Application number: PCT/SE2015/050419
Authority: WO
Inventors: Kuo-Yun LIANG; Assad ALAM
Original assignee: Scania Cv Ab
Priority date: 2014-04-08
Filing date: 2015-04-08
Publication date: 2015-10-15
Also published as: SE538458C2; SE1450433A1; DE112015001150B4; DE112015001150T5

Abstract

Method, device and system to support the creation of vehicle platoons in a set of vehicles, which comprises receiving information indicating a position for the respective vehicles in the set of vehicles, categorising the vehicles in the set into different categories based on a grouping for the respective vehicles, wherein the grouping indicates whether the vehicle is a single vehicle or already belongs to a vehicle platoon, determining a distance between at least two groupings, determining a profitability parameter β, which indicates whether it is profitable to form a vehicle platoon with the two groupings, based at least on the distance between the two groupings, analysing whether the profitability parameter β fulfils a profitability criterion, and generating a vehicle platoon signal φ based on the result of the analysis.

Description

Method, device and system for supporting the formation of platooning

Field of the invention

The present technology relates to vehicle platoons, and in particular a method, a device and a system to support the creation of a vehicle platoon in a set of vehicles. The technology also relates to a computer program and a computer program product.

Background of the invention

Cooperative driving with heavy goods vehicles such as trucks is on the increase. Cooperative driving is more generally known as platooning. Studies show that fuel consumption may be considerably reduced by way of platooning, i.e. vehicles driving close to each other with a suitable driving strategy. There are many different driving strategies regarding how the vehicles in a platoon should drive. However, there are no methods for knowing how and whether it is advantageous to change speeds in order to create a vehicle platoon, when already on the road.

A vehicle is rarely aware that there are other vehicles in the vicinity, with which it may be possible to form a platoon in order to save fuel. This may for example be vehicles with the same destination, or having a large part of the route in common. This means that few platoons may be created on the road, even though the vehicles are equipped with a cruise control for platooning.

One objective of the invention is to provide a tool that may support the creation of platoons with vehicles that are already on the road.

Summary of the invention

According to a first aspect, the above described objective is achieved through a method to support the creation of vehicle platoons in a set of vehicles. This method comprises:

- receiving information that indicates a position for the respective vehicles in the set of vehicles; - categorising the vehicles in the set into different categories, based on a grouping for each respective vehicle, where the grouping indicates whether the vehicle is alone or already part of a vehicle platoon;

- determining a distance between at least two groupings;

- determining a profitability parameter β, which indicates whether it is profitable to form a vehicle platoon with the two groupings, based at least on the distance between the two groupings;

- analysing whether the profitability parameter β fulfils a profitability criterion; and

- generating a vehicle platoon signal φ based on the result of the analysis.

By way of this method, it is possible to obtain a snapshot of where each vehicle in a set of vehicles is located at the present moment. Subsequently, it is possible to determine whether it is profitable for two or more vehicles in the set to form a platoon. By way of this method, a tool is obtained, enabling coordination of the vehicles in order to form a vehicle platoon, when the vehicles are already travelling. The method may result in several vehicle platoons, resulting in fuel savings. Through this method, an easier and/or faster manner of forming a vehicle platoon is also obtained, by way of reducing the number of calculations and data in relation to prior art methods.

According to one embodiment, a distance between at least two groupings, based on the respective positions of the groupings, is obtained. A vehicle's position may, according to one embodiment, be its geographical position. According to another embodiment, the information which indicates a vehicle's position may be a relative distance. By knowing one vehicle's geographical position, the second vehicle's position may then be determined since the relative distance between them is known.

According to one embodiment, the method comprises determining said distance between groupings within the same category. Accordingly, it is possible to determine whether it is profitable to form a vehicle platoon with vehicles being single vehicles in a set, with vehicle platoons comprising two vehicles, or with vehicle platoons comprising three vehicles etc.

According to one embodiment, said categories comprise the category "single vehicle", entailing that a grouping in the category comprises one vehicle and that the vehicle has at least a distance di to a nearest vehicle in the same lane and/or with the same driving direction. According to one embodiment, the groupings in the category "single vehicle" are handled before groupings in the remaining categories. The term "handling" means, in this context, that an evaluation of all vehicles which are single vehicles is carried out first, in order to determine whether they may form vehicle platoons with some other vehicle or vehicle platoon. For example, first the distance between single vehicles is determined, i.e. vehicles that are classified as single vehicles and whose grouping comprises one vehicle, and the profitability of forming vehicle platoons among these vehicles is determined as well. Accordingly, it is possible to determine whether it is profitable to form a vehicle platoon with vehicles, which are single vehicles in a set of vehicles. Subsequently, the distance between single vehicles and groupings comprising two or more vehicles may be determined, and the profitability of forming vehicle platoons among these vehicles may be determined as well.

According to one embodiment said categories comprise the category "vehicle platoons with two vehicles", which entails that a grouping in the category comprises two vehicles that have a distance between the vehicles, which is less than or equal to a distance di . According to another embodiment, the method comprises that groupings in the category "vehicle platoons with two vehicles" are handled after groupings in the category "single vehicle", but before groupings in the remaining categories. The term "handling" means, in this context, that all groupings with two vehicles are evaluated, in order to determine whether they may profitably form a platoon with another grouping with one, two or more vehicles. By handling these groupings after groupings with single vehicles, it is possible to wait for the single vehicles to be coordinated into vehicle platoons, meaning they will thus be comprised in a category with groupings comprising several vehicles.

According to another embodiment, said categories comprise the category "vehicle platoons with three vehicles", entailing that a grouping in this category comprises three vehicles with a distance between the vehicles, which is less than or equal to a distance di . However, there may be additional categories with more than three vehicles in each grouping. According to one embodiment, the method comprises sending the vehicle platoon signal φ to at least one of the two groupings. Thus, the driver, drivers and/or the vehicles may become aware that a vehicle platoon is about to be formed. The method may comprise generating a vehicle platoon signal φ that comprises an instruction to form a vehicle platoon. According to another embodiment, the method may comprise generating a vehicle platoon signal φ that comprises a control signal to at least one vehicle control device.

According to another embodiment, the method comprises determining a front grouping and a rear grouping among the two groupings. The rear grouping follows the front grouping in the driving direction. Accordingly, it is, for example, known which of the groupings (the rear) will catch up with another grouping (the front) when a profitability parameter β is determined. According to another embodiment, the front grouping, instead, may be configured to reduce its speed and to wait for the rear grouping. According to another embodiment, the embodiments may be combined, so that the front grouping reduces its speed, while the rear grouping increases its speed to catch up with the front grouping.

According to one embodiment, the method comprises determining of a distance 02 to a destination for the front grouping, and determining of a profitability parameter β, which indicates whether it is profitable to form a vehicle platoon with the two groupings, also based on the distance 02 to the destination for the front grouping. Accordingly, at the determination of a profitability parameter β, regard may be had to the distance remaining to the destination.

According to another embodiment, the method comprises determination of a profitability parameter β, which indicates whether it is profitable to form a vehicle platoon, also based on a cost of forming the vehicle platoon, based on an increased speed v and/or an estimated time t for the rear grouping to catch up with the front grouping. Accordingly, it is possible to include the cost arising when the vehicle platoon is actually formed, when determining the profitability

parameter β.

According to a second aspect, the objective is achieved with a device to support the creation of vehicle platoons in a set of vehicles. The device comprises a map unit with map data, a processor unit and a memory unit connected to the processor unit. The memory device comprises instructions to cause the processor unit:

- to receive information that indicates a geographic position for the respective vehicles in the set of vehicles;

- to categorise the vehicles in the set of vehicles into different categories, based on a grouping for each respective vehicle, wherein the grouping indicates whether the vehicle is alone or already part of a vehicle platoon;

- to determine a distance between at least two groupings;

- to determine a profitability parameter β, which indicates whether it is profitable to form a vehicle platoon with the two groupings, based at least on the distance between the two groupings;

- to analyse whether the profitability parameter β fulfils a profitability criterion; and

- to generate a vehicle platoon signal a based on the result of the analysis.

According to one embodiment, the control device is arranged to determine a distance between at least two groupings, based on the respective positions of the groupings. According to one embodiment, the device is arranged to determine said distance between groupings within the same category.

According to one embodiment, said categories comprise the category "single vehicle", entailing that a grouping in the category comprises one vehicle and that the vehicle has at least a distance di to a nearest vehicle in the same lane and/or with the same driving direction. According to another embodiment, the device is arranged to handle groupings in the category "single vehicle" before groupings in the remaining categories.

According to one embodiment, said categories comprise the category "vehicle platoons with two vehicles", which entails that a grouping in the category comprises two vehicles that have a distance between the vehicles, which is less than or equal to a distance di . According to another embodiment, the device is arranged to handle groupings in the category "vehicle platoons with two vehicles" after groupings in the category "single vehicle", but before groupings in the remaining categories.

According to one embodiment, said categories comprise the category "vehicle platoon with three vehicles", entailing that a grouping in the category comprises three vehicles with a distance between the vehicles, which is smaller than or equal to a distance di .

According to one embodiment, the device is arranged to send the vehicle platoon signal φ to at least one of the two groupings. According to another embodiment, the device is arranged to generate a vehicle platoon signal φ, comprising an instruction to form a vehicle platoon. According to another embodiment, the device is arranged to generate a vehicle platoon signal φ, comprising a control signal to at least one control device.

According to one embodiment, the device is arranged to determine a front grouping and a rear grouping among the two groupings. According to one embodiment, the device is arranged to determine a distance 02 to a destination for the front grouping, and to determine a profitability parameter β, which indicates whether it is profitable to form a vehicle platoon with the two groupings, also based on the distance 02 to the destination for the front grouping. According to another embodiment, the device is arranged to determine a profitability parameter β, which indicates whether it is profitable to form a vehicle platoon, also based on a cost of forming the vehicle platoon, based on an increased speed v and/or an estimated time t for the rear grouping to catch up with the front grouping.

According to a third aspect, the objective is at least partially achieved with a system comprising a device, wherein a device in the system is adapted to receive the vehicle platoon signal φ. According to a fourth aspect, the objective is achieved at least partly through a computer program P, wherein said computer program P comprises program code to cause a computer unit to carry out the steps according to the method.

According to a fourth aspect, the objective is achieved at least partly through a computer program product, comprising a program code stored on a computer- readable non-volatile medium, in order to carry out the steps according to the method when said program code is executed in a computer unit.

Preferred embodiments are described in the dependent claims and in the detailed description.

Brief description of the enclosed figures

The invention is described below with reference to the enclosed figures, of which: Fig. 1 shows a map with different roads drawn in, on which a number of vehicles are travelling.

Fig. 2 shows an example of a vehicle according to Fig. 1 . Fig. 3 illustrates a system with a device according to one embodiment of the invention.

Fig. 4 illustrates a flow chart for the method according to one embodiment.

Figs. 5A-5C show an example of how vehicles along a road in Fig. 1 are formed into vehicle platoons according to one embodiment of the invention.

Fig. 6 shows a diagram illustrating a profitability analysis of forming a vehicle platoon for four vehicles.

Detailed description of preferred embodiments of the invention

Fig. 1 shows a map 1 with a number of vehicles 3, preferably trucks, travelling along a road network between different towns 2. The towns 2 are marked with filled circles, and the vehicles 3 with empty circles. One objective of the invention is to facilitate and support the creation of vehicle platoons along these roads, when the vehicles 3 are already on the road. Being "on the road" means, in this context, that the vehicle 3 has started its journey from a starting point to a destination. A starting point may be a physical location of a haulage firm, an unloading or collection point, a rest area or similar. A destination may be a final destination for the vehicle 3, but in this context also the location of a road node, a crossroads, a junction or similar. The starting point and different destinations may, for example, be specified as geographical coordinates.

Fig. 2 shows an example of how a vehicle 3 shown on the map in Fig. 1 may be equipped. The vehicle 3 is here displayed in the form of a truck or a tractor, with a chassis 9 and two pairs of wheels 10a and 10B. The truck is displayed here only as an example, and the vehicle 3 may for example instead be a passenger car, a working vehicle or similar. The truck may also have one or several connected trailers. The vehicle 3 is equipped with a computer unit 4, for example in the form of a control device 4 and a positioning device 5. The positioning device 5 may, for example, be configured to receive signals from a global positioning system such as GNSS (Global Navigation Satellite System), for example GPS (Global

Positioning System), GLONASS, Galileo or Compass. Alternatively, the

positioning device 5 may be configured to receive signals from, for example, one or several detectors in the vehicle 3, measuring relative distances to for instance a road node, vehicles in the vicinity, or similar, which have a known position. Based on the relative distances, the positioning devices 5 may then determine the vehicle's position. A detector may also be configured to detect a signature in, for example, a road node, wherein the signature represents a certain position. The positioning device 5 may then be configured to determine its position by way of detecting the signature. The positioning device 5 may instead be configured to determine the signal strength in one or several signals from several base stations and/or road nodes etc. with a known position, and thus determine the vehicle's position by way of triangulation. Naturally, the above technologies may also be combined in order to ensure the vehicle's position. The positioning device 5 is configured to generate a positioning signal containing the vehicle's position, and to send this to one or several units in the vehicle 3. The vehicle 3 may also be equipped with a device 13 for wireless communication. The device 13 is configured to act as a receiver and sender of wireless signals. The device 13 may receive wireless signals from other vehicles and/or wireless signals from the infrastructure around the vehicle 3, and send wireless signals to other vehicles and/or wireless signals to the infrastructure around the vehicle 3. The wireless signals may comprise vehicle parameters from other vehicles, for example geographical position, destination, final destination, selected route, etc. A wireless signal usually also contains the vehicle identity, so that it is possible to identify the vehicle 3 from which the wireless signals originates. The vehicle 3 may also be equipped with a map unit 6, with a digital map of at least the road on which the vehicle 3 is driving. The driver may, according to one embodiment, specify a final destination and the map unit 6 may then, by way of knowing the current position of the vehicle, provide relevant map data about the future road between the current position and the final destination. Furthermore, the vehicle 3 may be equipped with a display unit 7, through which instructions may be conveyed to the driver. For example, the display unit 7 may be arranged to provide instructions visually via a display in the display unit 7. According to another alternative, the display unit 7 is arranged to provide instructions audibly via speakers in the display unit 7. The display unit 7 may also be arranged to provide instructions both visually and audibly. The vehicle 3 also comprises a control device 8, arranged to control the vehicle's speed. The control device 8 may, according to one embodiment, be a cruise control. The vehicle 3 may also be equipped with one or several detectors, which are generally displayed as a detector unit 14 to detect the surroundings, for example a radar unit, a laser unit, an inclinometer, etc. The detector device 14 is configured to detect a parameter, for example a relative distance to another vehicle. The detector device 14 is also configured to forward the detector signal to one or several devices in the vehicle 3. The vehicle 3 communicates internally between its different units via, for example, a bus, for example a CAN-bus (Controller Area Network) which uses a message- based protocol. Examples of other communication protocols that may be used are TTP (Time-Triggered Protocol), Flexray, etc. Thus, the signals and data described above may be exchanged between different devices in the vehicle 3. Signals and data may for example instead be transferred wirelessly between the various devices.

Each vehicle 3 may thus be equipped with a device for wireless communication 13. The vehicles in a set of vehicles may, according to one embodiment, communicate with each other via vehicle-to-vehicle communication or other means, such as for example via mobile communication devices, via an application in a communication device or via a server, and to infrastructure in the form of vehicle-to-infrastructure-communication. Infrastructure may for example be a road node, a server or similar. Road nodes, servers, etc. may also be equipped with a device for wireless communication (not displayed).

In order to support the formation of vehicle platoons, a device 1 1 , displayed in Fig. 3, may be implemented in the vehicle 3; a server, a road node, a computer in a haulage firm, in a FMS (Fleet Management System) or similar. The device 1 1 is comprised in a system to support the formation of vehicle platoons. The device 1 1 comprises a computer unit 4, which may for example be an electronic control device 4, if the device is implemented in a vehicle 3. The computer unit 4 may instead be a part of a server, a part of a road node or similar. The computer unit 4 comprises a processor unit 10 and a memory unit 9, connected to the processor unit 10. On the memory device 9 a computer program P is stored, which may cause the computer unit 4 to carry out the steps according to the method described herein. According to one embodiment, the memory device 9 is a part of the processor device 10. The processor device 10 may consist of one or several CPUs (Central Processing Units). The memory device 9 may comprise a nonvolatile memory, for example a flash-memory or a RAM (Random Access

Memory). The device 1 1 also comprises the map unit 6 with map data, as explained previously. The memory device 9 comprises instructions to cause the processor device 10 to execute a number of steps that will be described below.

In Fig. 3 a number of positioning devices 5A-5D are displayed, each of which has its physical location in a vehicle 3. Fig. 3 shows four positioning devices to illustrate the principle, but there may be more or fewer positioning devices. The positioning devices 5A-5D generate one positioning signal each, specifying the geographical position for the vehicle 3 in which the positioning device 5A-5D is fitted. These positions may then be sent via, for example, wireless communication to the computer unit 4. If the computer unit 4 is located in a vehicle, the vehicle's position is sent, via for example an internal network, to the computer unit 4. One or several positions may instead be positions, which are reported to the vehicle's respective haulage firm. The device 1 1 may then collect information about the positions from a computer or server at the haulage firm, where the positions are stored. The processor device 4 gains access to the geographical positions of the vehicles in the set, in this case comprising four vehicles (A1 , Fig. 4). With the help of the geographical positions from different vehicles 3 and map data from the map device 6, the processor device 10 may be configured to create a snapshot of where the vehicles in the set of vehicles are located, and potentially where they are heading. The positions of the vehicles may, according to one embodiment, also be determined by measuring relative distances between the vehicles. The control device 4 may then obtain information from one or several detector units 14 about one or several relative distances, and use this in the calculations. It may also be arranged to determine the geographical positions of one or several vehicles based on measured relative distances. The control device 4 generates, based on a profitability analysis, a vehicle platoon signal β, which, depending on the configuration, may be sent to a display unit 7 and/or to a control device 8 in one of the vehicles one of the groupings. Subsequently, a number of steps are carried out, which will be explained below in connection with the flow chart in Fig. 4.

In one step the vehicles in the set are categorised into different categories, based on a grouping for the respective vehicles, wherein the grouping indicates whether the vehicle is a single vehicle or already forms part of a platoon (A2). Since the geographical position of the respective vehicles may be known, the distance between the vehicles may also be calculated. Alternatively, distances between vehicles are obtained directly by way of relative measurements. In a sub-step of step A2, the distances between the vehicles in the set are determined, to see how they are grouped. It is then possible to see which vehicles are nearest to each other, and to determine how the vehicles are grouped. A grouping may comprise only one vehicle, two vehicles, three vehicles or more vehicles. Information about whether a vehicle forms part of a vehicle platoon may, according to one

embodiment, also be obtained by way of wirelessly transferred data, comprising the vehicle's vehicle platoon affiliation. This data is connected to the vehicle's vehicle identity. Vehicle platoon affiliation may indicate how many vehicles are comprised in the vehicle platoon. According to another embodiment, the device may determine how many vehicles are comprised in the same vehicle platoon by determining how many vehicles have the same vehicle platoon affiliation. Said categories comprise, according to one embodiment, the category "single vehicle", which entails that a grouping in the category comprises one vehicle, and that the vehicle has at least one distance di to the nearest vehicle in the same lane and/or with the same driving direction. According to another embodiment, said categories comprise the category "vehicle platoon with two vehicles", entailing that a grouping in the category comprises two vehicles, with a distance between the vehicles that is less than or equal to a distance di in the same lane and/or with the same driving direction. In addition, the two vehicles have at least one distance di to an additional nearest vehicle in the same lane. According to an additional embodiment, said categories comprise the category "vehicle platoon with three vehicles", entailing that a grouping in the category comprises three vehicles, with a distance between the vehicles that is less than or equal to a distance di in the same lane and/or with the same driving direction. Additionally, the three vehicles have at least one distance di to another nearest vehicle in the same lane and/or with the same driving direction. The distance di is, according to one embodiment, between 80 m - 100 m, for example 80, 90 or 100 m. In order to determine whether the vehicle is in the same lane, positions from the vehicle over a time period may be used, and a driving direction for the respective vehicle may be determined with the help of the respective positions over the time period. Instead, a so-called "heading" may be used, which may be included in the information about the vehicle's position. A "heading" or "direction" specifies the direction in which the vehicle moves. For example, the positioning device 5 may be arranged also to generate data about the vehicle's driving direction. The directions may then be compared to determine whether the vehicles are travelling in substantially the same direction. According to another embodiment, the direction is already known as an individual parameter, sent jointly with the vehicle's geographical position. Map data may also be used to determine whether the vehicle is located in the same lane and/or has the same driving direction.

In an additional step, a distance between at least two groupings is determined, based on the respective positions (A3) of the groupings. For example, the position may be a geographical position, and with the help of map data, the distance between the groupings may be determined. Alternatively, a relative distance between the groupings is measured. The term distance, as used in this context, means the distance between the groupings along the roads which connect the vehicles' positions, and on which the vehicles may travel. According to one embodiment the step comprises determining said distance between groupings within the same category. Thus, the distance between two single vehicles may be determined, the distance between groupings with two vehicles may be determined, and groupings with two vehicles may be determined. According to one embodiment, the groupings in the category "single vehicle" are handled before groupings in the remaining categories. Thus, "single" vehicles may be identified, i.e. vehicles which have a smallest distance di to their nearest vehicle. According to one embodiment, groupings in the category "vehicle platoons with two vehicles" are handled after groupings in the category "single vehicle", but before groupings in the remaining categories. By first handling single vehicles, and having them form vehicle platoons with groupings having one or several vehicles, and by subsequently having groupings comprising two vehicles form vehicle platoons with other vehicle platoons, studies show that the greatest savings are made.

Once a distance between two groupings has been determined, a profitability parameter β, which indicates whether it is profitable to form a vehicle platoon with the two groupings, based at least on the distance between the two groupings (A4), is determined. Subsequently, it is analysed whether the profitability parameter β fulfils a profitability criterion (A5), and a vehicle platoon signal a is generated based on the results of the analysis (A6). According to one

embodiment, a vehicle platoon signal φ, comprising an instruction to form a vehicle platoon, is generated. According to another embodiment, a vehicle platoon signal φ, comprising a control signal to at least one vehicle control device, is generated. The vehicle control device may for example be a cruise control, and the control signal may be a velocity reference to the cruise control. According to another embodiment, an interactor, for example the owner of the haulage firm, notifies one of the groupings that they must catch up with another grouping and form a vehicle platoon with it, once the interactor finds out the result of the analysis and this specifies that it is profitable to form a vehicle platoon. The vehicle platoon signal φ may be sent to the grouping via vehicle-to-vehicle communication, vehicle-to infrastructure communication or WLAN (Wireless Local Area Network). The vehicle platoon signal φ may be sent to the driver, for example to an application in a computer in the driver's cabin. The computer may for example be the driver's phone. The term "a set" as used in this context means a number of vehicles, whose geographical positions and/or relative distances between each other are evaluated in order to determine whether it is profitable to form a vehicle platoon with the vehicles. A set may, for example, be all vehicles travelling along a certain road section in the same driving direction, all vehicles from a certain haulage firm, all vehicles in a certain region or all vehicles driving past a certain road node over a certain time period in the same driving direction, and which are registered by the road node. A set may also consist of all vehicles within a certain region or road section with regard to a specific vehicle, with the same driving direction as the specific vehicle.

According to one embodiment, a profitability parameter β in the form of the distance between the two groupings is determined. The distance may, for example, be analysed by way of comparison with a predetermined or calculated greatest value which the distance is allowed to have. If the distance is smaller than the greatest value, a vehicle platoon signal a is generated, which, for example, specifies a speed that one of the two vehicles has to maintain in order for the vehicles to catch up with each other, so that they may form a vehicle platoon. According to one embodiment, the vehicle platoon signal φ is sent to at least one of the two groupings.

A distance between two groupings is determined as the smallest distance between the two groupings. If a grouping consists of several vehicles, the distance from the front vehicle, or the rear vehicle in the grouping, respectively, is determined, depending on where the second grouping is located.

According to one embodiment, the method comprises determining a front grouping and a rear grouping among the two groupings. The term "front grouping" as used in this context means the grouping of vehicles being at the very front in the driving direction of the two groupings. The term "rear grouping" as used in this context means the grouping of vehicles being at the very rear in the driving direction of the two groupings. A front grouping and a rear grouping may, for example, be determined by comparing the positions of the groupings and the directions with each other. The vehicle platoon signal φ may then be sent to the rear grouping of these groupings, and for example specify a speed, which the rear grouping must maintain in order to catch up with the front grouping. According to another embodiment, the vehicle platoon signal φ is sent to the front grouping of these groupings, and may for example specify a speed, which the front grouping must maintain in order for the rear grouping to be able to catch up with the front grouping. According to another embodiment, a vehicle platoon signal φ is sent to both the groupings. The contents thereof may differ, for example an instruction regarding a lower speed than the current speed to the front grouping, and an instruction regarding a higher speed than the current speed to the rear grouping. The speed or speeds may be speeds determined by the device and/or the system. According to one embodiment, the speed which the rear grouping must maintain to catch up with the front grouping may be a predetermined speed.

According to one embodiment, the speed which the front grouping must maintain for the rear grouping to catch up with the front grouping may be a predetermined speed. According to another embodiment, the speed or speeds may be

determined in profitability calculations and be used in the profitability analysis. For example, the speed or speeds required by the groupings, for those groupings to be able to form vehicle platoons within a certain time and/or section may be determined, and conveyed to the groupings. According to one embodiment, the distance between the groupings is here determined as the distance between the rear vehicle in the first grouping and the front vehicle in the rear grouping. One grouping of several vehicles may be arranged to receive the vehicle platoon signal φ via the front vehicle in the grouping, for example the leading vehicle, which thereafter controls the remaining vehicles in the grouping, based on the vehicle platoon signal φ. Alternatively, or in combination, all vehicles in the grouping are arranged to receive the vehicle platoon signal.

A vehicle's haulage firm usually has information about the destinations that the vehicle 3 will pass, and also the final destination of the vehicle. The driver of the vehicle 3 may also, with the help of a route planner in the vehicle 3, determine the route the vehicle 3 should take, and the destinations it will pass along the way. The final destination is, in most cases, known. A distance 02 from the vehicle's or the grouping's current position to one of its destinations, for example its final destination, may then be determined, based on the vehicle's current position and the position of the current destination. According to one embodiment, the method comprises determining a distance 02 to a destination for the front grouping, and determining a profitability parameter β, which indicates whether it is profitable to form a vehicle platoon with the two groupings, also based on the distance 02 to the destination for the front grouping. If, for example, the front grouping has a distance 02 to a selected destination, and the rear grouping may, by maintaining a maximum permitted speed or another speed, catch up with the front grouping before the front grouping has reached the selected destination, it may be deemed to be profitable to form a vehicle platoon comprising the front and the rear grouping. The computer unit 4 is, according to one embodiment, arranged to determine how long a distance d3 the rear grouping needs in order to reach the front grouping and to compare this distance with the distance 02. If d3 < 02 the computer unit is arranged to generate a vehicle platoon signal, which instructs the rear grouping to catch up with the front grouping, or to generate a vehicle platoon signal in the form of a control signal with the highest permitted speed or another speed. The speed may be a higher speed than the current speed that is set by the haulage firm, the device, the system or the driver. It is this speed that is also used in the profitability analysis. In figures 5A to 5C a scenario is illustrated where, first, in Fig. 5A, the single vehicles are located, in order to subsequently form the single vehicles into vehicle platoons with two vehicles in each vehicle platoon. Subsequently, the vehicle platoons with two vehicles are joined, in order to form a vehicle platoon with four vehicles. The figures show a road node 4 or a server 4, which organises and supports the formation of vehicle platoons. The set of vehicles here consists of four vehicles 3i, 3₂, 33 and 3₄. In more detail, Fig. 5A illustrates the vehicles 3i and 3₂ with the distance d₄ between the vehicles, the vehicles 33 and 3₄ with the distance d6 between each other, and the distance d₅ between the vehicles 3₂ and 33. Since d₅ is greater than both d₄ and d6, the vehicles 3i and 3₂ are deemed to be closest to each other, and the vehicles 33 and 3₄ are deemed to be closest to each other. All the vehicles are here at a greater distance than d₅ from the vehicles 3₂, 33 and 3₄. Since d₄ is greater than di, the vehicles 3i and 3₂, respectively, are grouped independently in the category "single vehicle". Since d6 is greater than di, the vehicles 33 ad 3₄, respectively, are grouped independently in the category "single vehicle". Profitability parameters β are then determined, indicating whether it is worth forming a vehicle platoon with vehicles 3i, 3₂, 33 and 3₄, which have all been placed in the category "single vehicle". Since it is desirable to first form a vehicle platoon with single vehicles having the smallest distances between each other, a rear vehicle platoon is formed consisting of the vehicles 3i and 3₂, and a vehicle platoon consisting of vehicles 33 and 3₄, which is displayed in Fig. 5B. Subsequently, a new categorisation of the groupings is carried out, where the conclusion is that vehicles 3i and 3₂ belong to the same grouping, since the distance d₄ between them is smaller than di, and that they now belong to the category "vehicle platoons with two vehicles". Likewise, it is established that vehicles 33 and 3₄ belong to the same grouping, since the distance d6 between them is smaller than di, and they now belong to the category "vehicle platoons with two vehicles". Subsequently, a profitability parameter β is determined among the groupings, indicating whether it is worthwhile forming a vehicle platoon with the groupings. In this case it is worthwhile, and a vehicle platoon signal is generated, indicating to the rear grouping that it should increase its speed, or controlling its speed, so that it maintains the maximum permitted speed and catches up with the front grouping, in order to form a joint vehicle platoon with four vehicles.

A profitability parameter may be determined in various ways. Two embodiments have already been described above, in one of which the profitability parameter β is the distance between the two groupings. In the second embodiment, the profitability parameter β is a distance d3, which specifies the distance that the rear grouping needs to catch up with the front grouping. Instead of a distance d3, the profitability parameter β may instead be specified as a time t₃ required for the rear grouping to catch up with the front grouping. The rear grouping in this case preferably has a maximum permitted speed. A vehicle 3, such as a truck, usually drives with a predetermined speed, for example 80 km/h. The maximum permitted speed may for example be 90 km/h. The device 1 1 and the method does not, according to one embodiment, need any information about the vehicle's speed, but may assume that the vehicle drives at 80 km/h. If the distance between the groupings is known, the distance d3 or the time t₃, which the rear grouping needs to catch up with the front grouping when the rear grouping drives at the maximum permitted speed, for example 90 km/h, may be calculated. According to another embodiment, there is knowledge about the vehicles' actual speeds, upon which the calculations may be based. Catching up means that the rear grouping comes closer to or equals the distance di from the front grouping.

The method may continue to support the creation of vehicle platoons as long as it is profitable, and as long as there is a set of vehicles to create vehicle platoons with.

Fig. 6 shows, by way of a diagram, another way of determining a profitability parameter β. In the diagram, it is assumed that the distances between the vehicles are equidistant, and that the set includes four vehicles. On one of the axes, a quota k1 is displayed, which is the coordination cost divided by the cost of not coordinating. The coordination cost may be determined as the cost of increasing the speed of the rear grouping to catch up with the front grouping. The cost of not coordinating may be determined as the cost of not forming a vehicle platoon. According to one embodiment, the cost of not coordinating is specified in ready tables. There are, for example, standard tables which specify how much energy that may be saved by being included in a vehicle platoon, depending on the vehicle's position in the vehicle platoon. On the second axis, a distance quota k2 is specified, which is the distance 02 to a destination for the front grouping divided by the distance between the front and the rear groupings. s1 shows the graph where the vehicles are coordinated, first in pairs, and subsequently maintain the speed. s2 shows the graph where the four vehicles are coordinated simultaneously and form a bigger vehicle platoon with four vehicles, and s3 shows the graph where the vehicles are first coordinated in pairs and subsequently coordinated again, to form a bigger vehicle platoon with four vehicles. In the diagram, everything above one is deemed to be not profitable, and below one is deemed as profitable. It is thus most profitable to form vehicle platoons with single vehicles as a priority. However, if the distance to the destination is too short, it may be better not to form any vehicle platoon at all. If, on the other hand, it is far to the destination, it may be favourable to form a longer vehicle platoon.

The method may thus comprise determination of a profitability parameter β, which indicates whether it is profitable to form a vehicle platoon, also based on at least one of the distances between the two groupings, or on a cost of forming the vehicle platoon, based on an increased speed v and/or an estimated time t for the rear grouping to catch up with the front grouping.

The present invention is not limited to the embodiments described above. Various alternatives, modifications and equivalents may be used. The embodiments above therefore do not limit the scope of the invention, which is defined by the enclosed claims.

Claims

1 . Method to support the formation of vehicle platoons in a set of vehicles, comprising:

- receiving information that indicates a position for the respective vehicles in the set of vehicles;

- categorising the vehicles in the set of vehicles into different categories, based on a grouping for each respective vehicle, wherein the grouping indicates whether the vehicle is alone or already part of a vehicle platoon;

- determining distance between at least two groupings;

- analysing whether the profitability parameter β fulfils a profitability criterion;

- generating a vehicle platoon signal φ, based on the result of the analysis.

2. Method according to claim 1 , which comprises determining said distance between groupings within the same category.

3. Method according to claim 1 or 2, wherein said categories comprise the category "single vehicle", which entails that a grouping in the category comprises one vehicle and that this vehicle has at least a distance di to a nearest vehicle in the same lane and/or with the same driving direction.

4. Method according to claim 3, wherein groupings in the category "single vehicle" are handled before groupings in the remaining categories.

5. Method according to one of the previous claims, wherein said categories comprise the category "vehicle platoons with two vehicles", which entails that a grouping in the category comprises two vehicles with a distance between the vehicles being smaller than or equal to a distance di .

6. Method according to claim 5, wherein groupings in the category "vehicle platoons with two vehicles" are handled after groupings in the category "single vehicle", but before groupings in the remaining categories.

7. Method according to one of the previous claims, wherein said categories comprise the category "vehicle platoons with three vehicles", which entails that a grouping in the category comprises three vehicles with a distance between the vehicles being smaller than or equal to a distance di .

8. Method according to one of the previous claims, which comprises sending the vehicle platoon signal φ to at least one of the two groupings.

9. Method according to one of the previous claims, which comprises determining a front grouping and a rear grouping among the two groupings.

10. Method according to claim 9, which comprises determining a distance 02 to a destination for the front grouping, and determining a profitability parameter β, which indicates whether it is profitable to form a vehicle platoon with the two groupings, also based on the distance 02 to the destination for the front grouping.

1 1 . Method according to claim 10, which comprises determining a profitability parameter β, which indicates whether it is profitable to form a vehicle platoon, also based on a cost of forming the vehicle platoon, based on an increased speed v and/or an estimated time t for the rear grouping to catch up with the front grouping.

12. Method according to any of the previous claims, which comprises generating a vehicle platoon signal φ that comprises an instruction to form a vehicle platoon.

13. Method according to any of the previous claims, which comprises generating a vehicle platoon signal φ that comprises a control signal to at least one vehicle control device.

14. Device to support the creation of a vehicle platoon in a set of vehicles, wherein the device comprises a map unit (7) with map data, a processor unit (12) and a memory unit (13) connected to the processor unit (12), wherein the memory unit (13) comprises instructions to cause the processor unit (12) to:

- receive information that indicates a position for the respective vehicles in the set of vehicles;

- categorise the vehicles in the set of vehicles into different categories, based on a grouping for each respective vehicle, wherein the grouping indicates whether the vehicle is alone or already part of a vehicle platoon;

- determine a distance between at least two groupings;

- determine a profitability parameter β, which indicates whether it is profitable to form a vehicle platoon with the two groupings, based at least on the distance between the two groupings;

- analyse whether the profitability parameter β fulfils a profitability criterion;

- generate a vehicle platoon signal a, based on the result of the analysis.

15. Device according to claim 14, which is arranged to determine said distance between groupings within the same category.

16. Device according to claim 14 or 15, wherein said categories comprise the category "single vehicle", entailing that a grouping in the category comprises one vehicle and that the vehicle has at least a distance di to a nearest vehicle in the same lane and/or with the same driving direction.

17. Device according to claim 16, which is arranged to handle groupings in the category "single vehicle" before groupings in the remaining categories.

18. Device according to any of claims 14 to 17, wherein said categories comprise the category "vehicle platoons with two vehicles", which entails that a grouping in the category comprises two vehicles, with a distance between the vehicles being smaller than or equal to a distance di .

19. Device according to claim 17 and 18, which is arranged to handle groupings in the category "vehicle platoons with two vehicles" after groupings in the category "single vehicle", but before groupings in the remaining categories.

20. Device according to any of claims 14 to 19, wherein said categories comprise the category "vehicle platoon with three vehicles", which entails that a grouping in the category comprises three vehicles with a distance between the vehicles being smaller than or equal to a distance di .

21 . Device according to any of claims 14 to 20, which is arranged to send the vehicle platoon signal φ to at least one of the two groupings.

22. Device according to any of claims 14 to 21 , which is arranged to determine a front grouping and a rear grouping among the two groupings.

23. Device according to claim 22, which is arranged to determine a distance 02 to a destination for the front grouping, and to determine a profitability parameter β, which indicates whether it is profitable to form a vehicle platoon with the two groupings, also based on the distance 02 to the destination for the front grouping.

24. Device according to claim 23, which is arranged to determine a profitability parameter β, which indicates whether it is profitable to form a vehicle platoon, also based on a cost of forming the vehicle platoon, based on an increased speed v and/or an estimated time t for the rear grouping to catch up with the front grouping.

25. Device according to any of claims 14 to 24, arranged to generate a vehicle platoon signal φ, comprising an instruction to form a vehicle platoon.

26. Device according to any of claims 14 to 25, which is arranged to generate a vehicle platoon signal φ, comprising a control signal to at least one control device.

27. System comprising a device according to any of claims 14 to 26, wherein a device in the system is adapted to receive the vehicle platoon signal φ.

28. Computer program P, wherein said computer program P comprises program code to cause a computer unit to carry out the steps according to any of claims 1 to 13.

29. Computer program product, comprising a program code stored on a computer readable non-volatile medium in order to execute the method steps according to any of claims 1 to 13, when said program code is executed in a computer unit.