SE540303C2

SE540303C2 - Device, system and method for assisting a driver in forming a platoon

Info

Publication number: SE540303C2
Application number: SE1550428A
Authority: SE
Inventors: Andersson Jonny; Alam Assad; Bredberg Linus
Original assignee: Scania Cv Ab
Priority date: 2015-04-10
Filing date: 2015-04-10
Publication date: 2018-05-29
Also published as: SE1550428A1; DE102016004291A1

Abstract

A device (3), a system (10) and a method for assisting a driver of a first vehicle (1) in forming a platoon with a second vehicle (2). The device (3) is configured to determine a position parameter and a velocity parameter of the second vehicle. The device (3) is further configured to determine a velocity change Δνfor the first vehicle (1) and/or a velocity change Δνfor the second vehicle (2) based on the position parameter and the velocity parameter of the second vehicle (2), in order to accomplish a distance d between the first vehicle (1) and the second vehicle (2) that meets a platoon criteria for forming a platoon. Based on the determination, the device (3) is configured to inform the driver of the first vehicle (1) of the possibility to form a platoon.

Description

Device, system and method for assisting a driver in forming a platoon Technical field The present disclosure relates to technology for platooning. In particular, the disclosure relates to a system, a method and a device for assisting a driver of a vehicle in forming a platoon. The disclosure also relates to a vehicle comprising the device, a computer program and a computer program product.

Background The European Union has set a goal of reducing greenhouse gases by 20% by 2020, and heavy vehicles currently account for 17% of the total CO2emissions in Europe. Thus, focus has been given on reducing fuel consumption of inter alia heavy vehicles to reach the goal and also to save on fuel costs. One way of reducing fuel consumption is to operate several vehicles in a chain formation, also known as platooning or a convoy.

Platooning take advantage of a reduced air drag by operating with small distances between vehicles. Under normal circumstances the air drag of a vehicle is proportional to the square of the vehicle’s velocity. This means that a reduction in speed from 90 km/h to 80 km/h reduces air drag by around 20 percent. Also, by staying close to a forward vehicle, an effect of reduced air drag can be obtained.

An adaptive cruise controller, ACC, enables both of the above mentioned techniques for reducing air drag and fuel consumption, namely: • Allowing a lower cruising speed than the preset speed to reduce air drag when a forward vehicle is present.

• Staying closer to a forward vehicle may reduce air drag due to the aerodynamic effects.

Hence, by operating several vehicles in a chain formation, a substantial fuel reduction can be obtained through automated systems. However, many drivers are not aware of the fact that fuel saving is possible by reducing the speed and/or by operating at small inter-vehicle spacing to a preceding heavy vehicle. Also many drivers that are aware of these facts still do not always actively search for other vehicles to platoon with.

In US2013/0080041A1 a convoy travel apparatus is described, that is capable of performing a vehicle travel control to organize a convoy travel of vehicles.

US2013/0261948A1 describes a periphery vehicle determination apparatus for determining an anteroposterior relation of periphery vehicles.

Summary The above described apparatuses are rather complicated, and even if there are automated systems, such as the ACC, drivers do not commonly find other vehicles to platoon with on the road as they e.g. may be out of sight, or are negligent about platooning possibilities.

It is an overall object of the disclosure to increase platooning activities on roads. It is an object of the disclosure to support a driver in finding possibilities of forming or joining a platoon. It is a further object of the disclosure to motivate the driver in forming or joining a platoon. It is a still further object of the disclosure to provide a method and/or device for finding possibilities of forming or joining a platoon and/or to motivate the driver to form or join a platoon that is easy to use for the driver. Any of these objects and others is at least partly achieved by the method and the device according to the independent claims, and by the embodiments according to the dependent claims.

According to a first aspect, the disclosure relates to a device for assisting a driver of a first vehicle in forming a platoon with a second vehicle. The device is configured to determine a position parameter and a velocity parameter of the second vehicle. The device is further configured to determine a velocity change ??1for the first vehicle and/or a velocity change ??2for the second vehicle based on the position parameter and the velocity parameter of the second vehicle, in order to accomplish a distance d between the first vehicle and the second vehicle that meets a platoon criteria for forming a platoon. Based on the determination, the device is configured to inform the driver of the first vehicle of the possibility to form a platoon.

With the above described device, the platooning rate on the roads may be increased significantly. The driver will be informed of any platooning possibility, even if the driver cannot see the possible platooning companion yet. The fuel consumption will then be reduced accordingly and any discharge of harmful exhaust gasses can be lowered.

According to one embodiment, the device is arranged to inform the driver of the first vehicle of the velocity change ??1for the first vehicle and/or the velocity change ??2for the second vehicle.

According to one embodiment, the platoon criteria include an upper limit for the distance d between the first vehicle and the second vehicle. According to one embodiment, the upper limit is velocity dependent.

According to one embodiment, the device is configured to inform the driver of the second vehicle of the velocity change ??1for the first vehicle and/or the velocity change ??2for the second vehicle.

According to one embodiment, the device is configured to determine a saving value a for the first vehicle and/or the second vehicle that is estimated to be obtained if the first vehicle and the second vehicle forms a platoon, and to inform the driver of the first vehicle of the saving value a. According to one embodiment, the device is configured to inform the driver of the second vehicle of the saving value a.

According to one embodiment, the device is configured to determine a distance d between the first vehicle and the second vehicle, and to inform the driver of the first vehicle of the distance d.

According to one embodiment, the device is configured to determine the velocity change ??1and/or ??2necessary for the first vehicle and the second vehicle to form the platoon within a certain time period ?t or within a certain length of the road ?l.

According to one embodiment, the device is configured to retrieve the position parameter and/or velocity parameter for the second vehicle via wireless communication.

According to one embodiment, the device is configured to retrieve the position parameter and/or velocity parameter for the second vehicle via one or several detectors located on the first and/or the second vehicle.

According to one embodiment, the device is configured to determine the saving value or values a based on the velocity of the first vehicle and/or the second vehicle.

According to one embodiment, the device is configured to generate a control signal indicating the velocity change ??1for the first vehicle, and to send it to a velocity control unit of the first vehicle, whereby the velocity of the first vehicle is regulated accordingly.

According to one embodiment, the device is configured to generate a control signal indicating the velocity change ??2for the second vehicle, and to send it to a velocity control unit of the second vehicle, whereby the velocity of the second vehicle is regulated accordingly.

According to a second aspect, the disclosure relates to a system for assisting a driver of a first vehicle in forming a platoon with a second vehicle. The system is configured to receive a position parameter and a velocity parameter of the second vehicle. The system is further configured to determine a velocity change ??1for the first vehicle and/or a velocity change ??2for the second vehicle based on the position parameter and the velocity parameter of the second vehicle, in order to accomplish a distance d between the first vehicle and the second vehicle that meets a platoon criteria for forming a platoon. Based on the determination, the system is further configured to generate information data and send it to a communication device in the first vehicle, whereby the driver of the first vehicle is informed of the possibility to form a platoon.

According to a third aspect, the disclosure relates to a method for assisting a driver of a first vehicle in forming a platoon with a second vehicle. The method comprises to: - determining a position parameter and a velocity parameter of the second vehicle; - determining a velocity change ??1for the first vehicle and/or a velocity change ??2for the second vehicle based on the position parameter and the velocity parameter of the second vehicle, in order to accomplish a distance d between the first vehicle and the second vehicle that meets a platoon criteria for forming a platoon; and based on the determining - informing the driver of the first vehicle of the possibility to form a platoon.

According to one embodiment, the method comprises informing the driver of the first vehicle of the velocity change ??1for the first vehicle and/or the velocity change ??2for the second vehicle.

According to one embodiment, the method comprising informing the driver of the second vehicle of the velocity change ??1for the first vehicle and/or the velocity change ??2for the second vehicle.

According to one embodiment, the method comprises determining a saving value a for the first vehicle and/or the second vehicle that is estimated to be obtained if the first vehicle and the second vehicle forms a platoon, and informing the driver of the first vehicle of the saving value a.

According to one embodiment, the method comprises informing the driver of the second vehicle of the saving value a.

According to one embodiment, the method comprises determining a current distance d between the first vehicle and the second vehicle, and informing the driver of the first vehicle of the current distance d.

According to one embodiment, the method comprises determining the velocity change ??1and/or ??2necessary for the first vehicle and the second vehicle to form the platoon within a certain time period ?t or within a certain length of the road ?l .

According to one embodiment, the method comprises retrieving the position parameter and/or velocity parameter for the second vehicle via wireless communication. According to another embodiment, the method comprises retrieving the position parameter and/or velocity parameter for the second vehicle via one or several detectors located on the first and/or the second vehicle.

According to one embodiment, the method comprises determining the saving value or values a based on the velocity of the first vehicle and/or the second vehicle.

According to one embodiment, the method comprises regulating the velocity of the first vehicle according to the velocity change ??1for the first vehicle.

According to one embodiment, the method comprises regulating the velocity of the second vehicle according to the velocity change ??2for the second vehicle.

According to a fourth aspect, the disclosure relates to a computer program P, wherein the computer program P comprises a computer program code to cause a device, or a computer connected to said device, to perform the method as disclosed herein.

According to a fifth aspect, the disclosure relates to a computer program product comprising a computer program code stored on a computer-readable medium to perform the method according to any of the disclosed method steps, when the computer program code is executed by a device or by a computer connected to the device.

Brief description of the drawings Fig. 1 illustrates an example of a system and a device according to one embodiment of the invention.

Fig. 2 illustrates a screen where information regarding possibility to form a platoon is shown.

Fig. 3 illustrates an example where a system according to the disclosure may be used.

Fig. 4 illustrates a method according to one embodiment of the disclosure.

Detailed description In Fig. 1 a device 3 for assisting a driver of a first vehicle 1 (Fig. 3) in forming a platoon with a second vehicle 2 (Fig. 3) is shown. The device 3 is arranged to execute a plurality of steps in order to facilitate ad-hoc platooning between two vehicles during driving on a road. The device 3 may be part of a system 10. The device 3 may be included in an off-board system 11 (Fig. 3). A device 3 may instead be implemented in one or both of the first vehicle 1 and second vehicle 2. The device 3 may be implemented as an ECU, Electronic Control Unit, or be included in an ECU, in one or both of the vehicles 1, 2. The device 3 may also partly or in total be implemented in a communication device such as a smartphone (not shown) or a computer such as a tablet (not shown). Further, the system 10 including the device 3 may be implemented partly in an off-board system 11, partly in one or both of the vehicles 1, 2, and/or partly in one or several communication devices and/or one or several computers (not shown).

The device 3 will now be described with reference to Fig. 1. The device 3 includes a processing unit 4 and a memory unit 5. The processing unit 4 may be made up of one or more Central Processing Units (CPUs). Further, the memory unit 5 may be made up of one or more memory units. A memory unit 5 may include a volatile and/or a non-volatile memory, such as a flash memory or Random Access Memory (RAM). The memory unit 5 further includes a computer program P including a computer program code to cause the system 10, device 3, a communication device and/or a computer connected to the device 3, to perform any of the steps that will be described in the following. The described units 4, 5 may thus be incorporated in any of the described devices or be distributed to or distributed between any of the other described devices.

The device 3 is configured to determine a position parameter and a velocity parameter of the second vehicle 2. The position parameter may be a relative distance ?p between the first vehicle 1 and the second vehicle 2. This relative distance ?p may be measured by means of a detector unit 8 such as radar unit, lidar unit, camera unit, video recording unit or any other suitable detector unit located on the first vehicle 1 or the second vehicle 2. The velocity parameter may be a relative velocity ?? between the first vehicle 1 and the second vehicle 2. This relative velocity ?? may be measured by means of a detector unit 8 such as radar unit, lidar unit, camera unit, video recording unit or any other suitable detector unit located on the first vehicle 1 or the second vehicle 2. The mentioned detectors are indicated generally by the detector unit 8 in Fig. 1, but it is understood that in the system 10 data may be obtained from a plurality of detector units.

The position parameter of the second vehicle 2 may instead be an actual position P2of the second vehicle 2 retrieved from the second vehicle 2 itself. Also, the velocity parameter of the second vehicle 2 may instead be an actual velocity v2of the second vehicle 2 retrieved from the second vehicle 2 itself. These parameters are normally available via an internal network of the vehicle 2 from a positioning unit and velocity unit in the vehicle 2, jointly refereed to as 6 in Fig. 1. In Fig. 1 the position parameter and the velocity parameter are denoted pxand vX, respectively, as it may also be possible to retrieve also the position pi and the velocity Vi of the first vehicle 1 via an internal network of the first vehicle 1, via a corresponding positioning unit and velocity unit in the vehicle 1. Thus, pxmay denote p1or p2, and vxmay denote v1or v2depending on inter alia where the device 3 is located.

The vehicle 1 may communicate internally between its units, devices, sensors, detectors etc. via a communication 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. In that way signals and data described herein may be exchanged between different units, devices, sensors and/or detectors in the vehicle 1, 2. Signals and data may instead be transferred wirelessly between the different units, devices, sensors and/or detectors.

The positioning unit is arranged to determine the position of the vehicle 1, 2, and may 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 unit may be configured to receive signals from for example one or several distance detectors 8 in the vehicle 1, 2 that measure relative distances to for example a road side unit, nearby vehicles or similar with a known position. Based on the relative distance or distances the positioning unit may determine the position of the own vehicle 1, 2. A detector 8 may also be configured to detect a signature in for example a road side unit, whereby the signature represents a certain position. The positioning unit may then be configured to determine its own position via detection of the signature. The positioning unit may instead be configured to determine the signal strength in one or a plurality of signals from a base station or road side unit with known position, and thereby determine the position of the vehicle 1, 2 by using triangulation. Some of above mentioned technologies may of course be combined to ensure a correct position determination of the vehicle 1, 2. The positioning unit is configured to generate a position signal with the position p1, p2of the vehicle 1, 2, and to send it to the device 3.

The position parameter and the velocity parameter may be sent via wireless communication to an entity in the system 10 capable of receiving data wirelessly. For example, each vehicle 1, 2, the off-board system 11 and any communication device may be arranged with a transceiver 7 for wireless transmission and reception of data. In Fig. 1 the position parameter and the velocity parameter are denoted pxand vx, respectively, as it may also be possible to retrieve the position Pi and the velocity v1of the first vehicle 1 via wireless transmission. Thus, pxmay denote pi and/or p2, and vxmay denote v1and/or v2depending on inter alia where the device 3 is located. Also, identification data identifying the vehicle 1 and the vehicle 2, respectively, may be sent via wireless communication. The position parameter, velocity parameter etc may be tagged with identification data to be able to known from which vehicle the parameter or data pertain.

The first vehicle 1 and the second vehicle 2 may be arranged to communicate directly with each other via wireless communication. One kind of such wireless communication is referred to as vehicle-to-vehicle communication (V2V). The first vehicle 1 and the second vehicle 2 may also be arranged to communicate with each other via the off-board system 11 (Fig. 3), a server, a road side unit or similar. One kind of such wireless communication is referred to as vehicle-toinfrastructure communication (V2I). The wireless communication may also be performed via mobile communication servers, via an application in a communication unit or via a server.

The device 3 is further configured to determine a velocity change ??1for the first vehicle 1 and/or a velocity change ??2for the second vehicle 2 based on the position parameter and the velocity parameter of the second vehicle 2, in order to accomplish a distance d between the first vehicle 1 and the second vehicle 2 that meets a platoon criteria for forming a platoon. The platoon criteria may include an upper limit for the distance d between the first vehicle 1 and the second vehicle. The upper limit may be velocity dependent. The device 3 may further be configured to determine the velocity change ??1and/or ??2necessary for the first vehicle 1 and the second vehicle 2 to form the platoon within a certain time period ?t or within a certain length of the road ?l. The velocity change may be negative, for example if the vehicle is the foremost vehicle of the two vehicles 1, 2, and it is determined that the vehicle should slow down its velocity in order to form a platoon.

Based on the determination of the velocity change or changes, the device 3 is arranged to inform the driver of the first vehicle 1 of the possibility to form a platoon. The first vehicle 1 may be the subsequent vehicle of the first vehicle 1 and the second vehicle 2 in the driving direction. Instead, the first vehicle 1 may be the foremost vehicle of the first vehicle 1 and the second vehicle 2 in the driving direction. According to one embodiment, the device 3 is arranged to inform the driver of the second vehicle 2 of the possibility to form a platoon.

The device 3 may be configured to inform the driver of the first vehicle 1 of the velocity change ??1for the first vehicle 1 and/or the velocity change ??2for the second vehicle 2. The device 3 may further be configured to inform the driver of the second vehicle 2 of the velocity change ??1for the first vehicle 1 and/or the velocity change ??2for the second vehicle 2. For example, the driver of the first vehicle 1 may be informed of the velocity change ??1necessary for the first vehicle 1 to form the platoon, and the driver of the second vehicle 2 may be informed of the velocity change ??2necessary for the second vehicle to form the platoon.

The device 3 may further be configured to determine a saving value ? for the first vehicle 1 and/or the second vehicle 2 that is estimated to be obtained if the first vehicle 1 and the second vehicle 2 form a platoon, and to inform the driver of the first vehicle 1 of the saving value ?. The device 3 may also be configured to inform the driver of the second vehicle 2 of the saving value ?. The saving value ? may be an estimated fuel saving shown as a percentage of the current total fuel consumption for any or both of the vehicles 1, 2, or an estimated decrease in air resistance as a percentage of the current total air resistance for any or both of the vehicles 1, 2. The saving value or values a may be determined based on the velocity of the first vehicle 1 and/or the second vehicle 2, e.g. the velocity the vehicles will have when the platoon is established. According to one embodiment, if the saving value ? includes a saving for the first vehicle 1, it is also informed to the driver of the first vehicle 1. According to a further embodiment, if the saving value ? includes a saving for the second vehicle 2, it is informed to the driver of the second vehicle 2.

According to one embodiment, the device 3 may be configured to determine a distance d between the first vehicle 1 and the second vehicle 2, and to inform the driver of the first vehicle 1 of the distance d. The device 3 may also be configured to inform the driver of the second vehicle 2 of the distance d. The device 3 may be configured to compare the distance d with a predetermined limit for the distance. If the distance d is larger than the predetermined limit, the device 3 may determine that there is no possibility for the vehicles 1, 2 to form a platoon. The possible platooning possibility between the vehicles 1, 2 may then be discarded.

Information to a driver may be given through a communication device by visual means, through sound means or by tactile feedback means. The device 3 is configured to generate information data such as an information signal, with the information, e.g. saving value ?, distance d and/or velocity change ???, and send the information data or information signal to the visual means, sound means or tactile feedback means. An example of information by visual means is shown in Fig. 2, illustrating a display 9. The display 9 may be a built-in display in the instrument panel, a head-up display (HUD), a display of the communication device etc. Data, for example the determined velocity change ??1and/or ??2, the current distance d between the vehicles 1, 2, the saving value ?, have been sent to the display 9. The total new velocity of the vehicle, calculated by adding the velocity change to the current velocity of the vehicle, may also be presented. As can be seen from the display 9, the velocity change should be 5km/h, the saving value will be 5%, and the distance d to the other vehicle is 500m. The driver will then be aware of that there is a platooning opportunity, and may change the velocity of the vehicle accordingly. Another kind of visual means may be a LED, Light Emitting Diod, or other kind of lamp that is illuminated when there is a platooning possibility.

The device 3 may be configured to generate a control signal indicating the velocity change ??1for the first vehicle 1, and to send it to a velocity control unit (not shown) of the first vehicle 1, whereby the velocity of the first vehicle 1 is regulated accordingly. The device 3 may further be configured to generate a control signal indicating the velocity change ??2for the second vehicle 2, and to send it to a velocity control unit (not shown) of the second vehicle 2, whereby the velocity of the second vehicle 2 is regulated accordingly. Thus, the first vehicle 1 or the second vehicle 2 may be controlled automatically according to the determined velocity change. The driver of the vehicle may be presented with any of the above-mentioned information, and may thereafter initiate the automated velocity change of the vehicle in order to form a platoon. The driver may be presented with a virtual icon asking if the driver wants to initiate the automated velocity change, and by touching the icon initiating the automated velocity change. The driver may instead initiate the automated velocity change by actuating a lever or control, or by voice input to the system 10.

The disclosure also relates to a method for assisting a driver of the first vehicle 1 in forming a platoon with the second vehicle 2. The method may be implemented as computer program code of a computer program P saved in the memory unit 5 8Fig. 1), and executed by the processing unit 4 (Fig. 1) of the device 3 in the system 10. The method will now be described with reference to the example illustrated in Fig. 3 and the flowchart in Fig. 4.

In the example of Fig. 3, two vehicles are travelling in the same direction indicated by the arrow on the road. The first vehicle 1 is a subsequent vehicle to the second vehicle 2. In another example, the driving direction may be the opposite, such that the second vehicle 2 is the subsequent vehicle to the first vehicle 1. The vehicles are travelling in a curve, and none of the drivers are able to see the other vehicle.

The method may start with detecting if there is a vehicle to platoon with in the neighborhood, or detecting that there are two vehicles that might be able to platoon together that are in the same neighborhood. The method may include collecting route information, or destination information, from the vehicles to find out if the vehicles are following the same route, and/or vehicle characteristics, e.g. trailer-type information, to find out if it is suitable for the vehicles to form a platoon. For example, it may be determined to only platoon with other heavy vehicles, such as lorries. The method may compare the current distance d between the vehicles with a predetermined limit for the distance. If the current distance d between the vehicles is larger than the predetermined limit, the method may determine that there is no possibility for the vehicles to form a platoon. The possible platooning possibility between the vehicles may then be discarded. The most suitable vehicle may be selected, and may be referred to as the second vehicle 2 in this disclosure. For example, the closest heavy-vehicle with a route at least partly the same as the first vehicle may be selected as the second vehicle 2.

The method comprises to determine a position parameter and a velocity parameter of the second vehicle 2 (A1). As the vehicles 1, 2 in the example are travelling in the curve, there is no possibility to retrieve any position or velocity parameters from the second vehicle 2 by using any detectors 8 in any of the vehicles 1, 2. Instead, data about velocities of each vehicle v1, v2and positions pi, P2are needed and are instead sent to an off-board system 11 via wireless communication.

The method then comprises to determine a velocity change ??1for the first vehicle 1 and/or a velocity change ??2for the second vehicle 2 based on the position parameter and the velocity parameter of the second vehicle 2, in order to accomplish a distance d between the first vehicle 1 and the second vehicle 2 that meets a platoon criteria for forming a platoon (A2). For example, the platoon criteria may include an upper limit for the distance d between the first vehicle 1 and the second vehicle 2. The upper limit may be velocity dependent, thus dependent on the velocity of the first and/or the second vehicle 1, 2. The method may include to determine the velocity change ??1and/or ??2necessary for the first vehicle 1 and the second vehicle 2 to form the platoon within a certain time period ?t or within a certain length of the road ?l.

In the example in Fig. 4, the determination is also based on the velocity parameter v1and the position parameter pi of the first vehicle 1. By means of map data and possible route information about the routes of the vehicles 1, 2, the distance d may be determined between the vehicles 1, 2. Then the appropriate velocity change or changes ??1, Av2may be determined by appropriate calculations.

These calculations are known to the person skilled in the art, and will not be further explained here. The calculations are made in the off-board system 11 (Fig. 11).

Based on the above determining and others, the method further comprises to inform the driver of the first vehicle 1 of the possibility to form a platoon (A3). The method may also comprise to inform the driver of the second vehicle 2 of the possibility to form a platoon. The information may include a short message via visual means, through sound means or by tactile feedback means, that there is a possibility to form a platoon with another vehicle.

Further, the method may comprise to inform the driver of the first vehicle 1 of the velocity change ??1for the first vehicle 1 and/or the velocity change ??2for the second vehicle 2. The method may further comprise to inform the driver of the first vehicle 1 of the current distance d.

The method may also comprise to determine a saving value ? for the first vehicle 1 and/or the second vehicle 2 that is estimated to be obtained if the first vehicle 1 and the second vehicle 2 form a platoon, and informing the driver of the first vehicle 1 of the saving value ?. The method may include determining the saving value or values a based on the velocity of the first vehicle 1 and/or the second vehicle 2.

In the example of Fig. 3, the driver of the first vehicle now gets the short visual message via a head-up display in the first vehicle 1 reading “Platooning possibility” and the driver is requested to make an input to the system 10 to find out more about the possibility to platoon. This information is sent via wireless communication from the off-board system 11. The driver says “Yes” and the system 10 gives via the head-up display more information to the driver. The driver gets the information that is shown in the display of Fig. 2. The driver now knows that there is a possible platooning companion 500 meters in front of the first vehicle 1, and that the he will make a 5% fuel saving if he increases the velocity of the first vehicle 1 with 5 km/h and catches up with the foremost second vehicle 2 and forms a platoon with the second vehicle 2.

The method may further comprise to inform the driver of the second vehicle 2 of the velocity change ??1for the first vehicle 1 and/or any velocity change ??2for the second vehicle 2, and/or the saving value ?, and/or the current distance d. Thus, the driver of the second vehicle 2 may be informed via a head-up display or similar just as previously described with reference to information shown to the driver of the first vehicle 1.

The method may further comprise to regulate the velocity of the first vehicle 1 according to the velocity change ??1for the first vehicle 1, and/or regulating the velocity of the second vehicle 2 according to the velocity change ??2for the second vehicle 2.

In the example shown in Fig. 4, the driver of the first vehicle 1 decides that he wants to catch up with the second vehicle 2. The driver of the first vehicle 1 hits a virtual icon on the head-up display and the first vehicle 1 increases its velocity with 5 km/h and will soon catch up with the second vehicle 2. The driver of the second vehicle 2 may be informed that the first vehicle 1 is approaching in order to platoon with the second vehicle 2.

When the first vehicle 1 approaches the second vehicle 2, the vehicles 1, 2 may initiate a platooning procedure to form a platoon. For example, the order of the vehicles 1, 2 may be determined based on vehicle characteristics to get the largest fuel savings. Also, it may be determined if the platoon should be formed with adaptive cruise control from the subsequent vehicle, or if functions of the subsequent vehicle should be overtaken by the foremost vehicle. Further, an acknowledgement from the second vehicle 2 that the second vehicle 2 accepts to platoon with the first vehicle 1 may be demanded before any velocity change is started.

The present invention is not limited to the above-described preferred embodiments. Various alternatives, modifications and equivalents may be used. Therefore, the above embodiments should not be taken as limiting the scope of the invention, which is defined by the appending claims.

Claims

1. A device (3) for assisting a driver of a first vehicle (1) in forming a platoon with a second vehicle (2), the device (3) is configured to determine a position parameter and a velocity parameter of the second vehicle (2), characterized in that the device (3) further is configured to: - determine a velocity change ??1for the first vehicle (1) and/or a velocity change ??2for the second vehicle (2) based on the position parameter and the velocity parameter of the second vehicle (2), in order to accomplish a distance d between the first vehicle (1) and the second vehicle (2) that meets a platoon criteria for forming a platoon including to determine the velocity change ??1and/or ??2necessary for the first vehicle (1) and the second vehicle (2) to form the platoon within a certain time period ?t or within a certain length of the road ?l; and based on said determination: - inform the driver of the first vehicle (1) of the possibility to form a platoon including to inform the driver of the first vehicle (1) of the velocity change ??1for the first vehicle (1) and/or the velocity change ??2for the second vehicle (2), wherein the device (3) further is configured to determine a current distance d between the first vehicle (1) and the second vehicle (2), and to inform the driver of the first vehicle (1) of the current distance d.

2. The device (3) according to claim 1, wherein the platoon criteria include an upper limit for the distance d between the first vehicle (1) and the second vehicle (2).

3. The device (3) according to claim 2, wherein the upper limit is velocity dependent.

4. The device (3) according to any of the preceding claims, configured to inform the driver of the second vehicle (2) of the velocity change ??1for the first vehicle (1) and/or the velocity change ??2for the second vehicle (2).

5. The device (3) according to any of the preceding claims, configured to determine a saving value ? for the first vehicle (1) and/or the second vehicle (2) that is estimated to be obtained if the first vehicle (1) and the second vehicle (2) forms a platoon, and to inform the driver of the first vehicle (1) of the saving value ?.

6. The device (3) according to claim 5, configured to inform the driver of the second vehicle (2) of the saving value a.

7. The device (3) according to any of the preceding claims, configured to retrieve the position parameter and/or velocity parameter for the second vehicle (2) via wireless communication.

8. The device (3) according to any of the preceding claims, configured to retrieve the position parameter and/or velocity parameter for the second vehicle (2) via one or several detectors (8) located on the first (1) and/or the second vehicle (2).

9. The device (3) according to any of the preceding claims, configured to determine wherein the saving value or values a based on the velocity of the first vehicle (1) and/or the second vehicle (2).

10. The device (3) according to any of the preceding claims, configured to generate a control signal indicating the velocity change ??1for the first vehicle (1), and to send it to a velocity control unit of the first vehicle (1), whereby the velocity of the first vehicle (1) is regulated accordingly.

11. The device (3) according to any of the preceding claims, configured to generate a control signal indicating the velocity change ??2for the second vehicle (2), and to send it to a velocity control unit of the second vehicle (2), whereby the velocity of the second vehicle (2) is regulated accordingly.

12. A system (10) for assisting a driver of a first vehicle (1) in forming a platoon with a second vehicle (2), the system (10) is configured to receive a position parameter and a velocity parameter of the second vehicle (2), characterized in that the system (10) further is configured to: - determine a velocity change ??1for the first vehicle (1) and/or a velocity change ??2for the second vehicle (2) based on the position parameter and the velocity parameter of the second vehicle (2), in order to accomplish a distance d between the first vehicle (1) and the second vehicle (2) that meets a platoon criteria for forming a platoon including to determine the velocity change ??1and/or ??2necessary for the first vehicle (1) and the second vehicle (2) to form the platoon within a certain time period ?t or within a certain length of the road ?l; and based on said determination: - generate information data and send it to a communication device in the first vehicle (1), whereby the driver of the first vehicle (1) is informed of the possibility to form a platoon wherein the information data includes the velocity change ??1for the first vehicle (1) and/or the velocity change ??2for the second vehicle (2), wherein the system (10) further is configured to determine a current distance d between the first vehicle (1) and the second vehicle (2), and wherein the information data includes the current distance d.

13. A method for assisting a driver of a first vehicle (1) in forming a platoon with a second vehicle (2), the method comprises: - determining a position parameter and a velocity parameter of the second vehicle (2); - determining a velocity change ??1for the first vehicle (1) and/or a velocity change ??2for the second vehicle (2) based on the position parameter and the velocity parameter of the second vehicle (2), in order to accomplish a distance d between the first vehicle (1) and the second vehicle (2) that meets a platoon criteria for forming a platoon including determining the velocity change ??1and/or ??2necessary for the first vehicle (1) and the second vehicle (2) to form the platoon within a certain time period ?t or within a certain length of the road ?l; and based on said determining - informing the driver of the first vehicle (1) of the possibility to form a platoon including informing the driver of the first vehicle (1) of the velocity change ??1for the first vehicle (1) and/or the velocity change ??2for the second vehicle (2), wherein the method further includes - determining a current distance d between the first vehicle (1) and the second vehicle (2), and informing the driver of the first vehicle (1) of the current distance d.

14. A computer program P, wherein said computer program P comprises a computer program code to cause a device (3), or a computer connected to said device (3), to perform the method according to claim 13.

15. A computer program product comprising a computer program code stored on a computer-readable medium to perform the method according to claim 13, when said computer program code is executed by a device (3) or by a computer connected to said device (3).