SE541346C2

SE541346C2 - Method and control unit for maintaining a formation of vehicles co-ordinated to perform a common task

Info

Publication number: SE541346C2
Application number: SE1651166A
Authority: SE
Inventors: Kuo-Yun Liang; Marco Trincavelli; Samuel Malinen; Zhan Wang
Original assignee: Scania Cv Ab
Priority date: 2016-08-31
Filing date: 2016-08-31
Publication date: 2019-07-23
Also published as: SE1651166A1; DE102017007980A1

Abstract

Method (300) and control unit (210), in a vehicle (101), for maintaining a formation (100) comprising a plurality of laterally displaced vehicles (101, 102). The method (300) comprises: determining (301) a lateral displacement distance (150) of at least one other vehicle (102) in the formation (100), in relation to the vehicle (101), via a sensor (140); and adjusting (302) the lateral position of the vehicle (101) in relation to the other vehicle (102), when the determined (301) lateral displacement distance (150) is outside a lateral threshold interval (160, 170).

Description

METHOD AND CONTROL UNIT FOR MAINTAINING A FORMATION OF VEHICLES CO-ORDINATED TO PERFORM A COMMON TASK TECHNICAL FIELD This document discloses a control unit and a method in a control unit in a vehicle. More particularly, a method and a control unit is provided for maintaining a formation comprising a plurality of displaced vehicles.

BACKGROUND Snow ploughing is a critical operation in wintertime for airports located at cold climate locations. It has to be performed fast to minimise disturbance on the air services and at the same time accurately to ensure safety of flights. Snow ploughing is usually performed by a fleet of snow ploughing vehicles that proceed in formation cleaning the whole landing stripe.

For performing tasks like snow ploughing, heavy vehicles need to proceed in an organised formation wherein the vehicles are laterally displaced. Errors in the alignment of the formation results in a low quality outcome for the snow ploughing procedure, which could result in the need of redoing the whole operation from scratch. Thereby, the air traffic is delayed. Further, in case snow is not completely removed from the landing stripe, an accident may occur.

When two or more vehicles are driving in a formation, the position of each vehicle needs to be determined very accurately to not break the formation and/ or to cause accidents. Global Positioning System (GPS) based technology is too inaccurate for providing the required level of accuracy. On the other hand, differential GPS techniques like Real Time Kinematic (RTK)-GPS may be too expensive or too unreliable in presence of extreme weather conditions.

Similar problems as described above may result also in other situations where vehicles are to drive in a formation wherein the vehicles are laterally displaced, in order to perform a common task. Some examples may be for example agricultural machineries, e.g. combine harvesters, tractors; or construction machines, e.g. bulldozers, graders, road rollers; minesweepers; lawn movers; cleaning devices, etc.

It appears that further development is required for improving driving within a formation of a plurality of vehicles.

SUMMARY It is therefore an object of this invention to solve at least some of the above problems and maintaining a formation comprising a plurality of vehicles.

According to a first aspect of the invention, this objective is achieved by a method in a control unit of a vehicle. The method aims at maintaining a formation comprising a plurality of laterally displaced vehicles. The method comprises determining a lateral displacement distance of at least one other vehicle in the formation, in relation to the vehicle, via a sensor. Further the method also comprises adjusting the lateral position of the vehicle in relation to the other vehicle, when the determined lateral displacement distance is outside a lateral threshold interval.

According to a second aspect of the invention, this objective is achieved by a control unit in a vehicle. The control unit aims at maintaining a formation comprising a plurality of laterally displaced vehicles. The control unit is configured to determine a lateral displacement distance of at least one other vehicle in the formation, in relation to the vehicle, via a sensor. Further the control unit is configured to generate a command signal to adjust the lateral position of the vehicle in relation to the other vehicle, when the determined lateral displacement distance is outside a lateral threshold interval.

Thanks to the described aspects, by continuously or at predetermined or configurable time intervals measure distance and/ or angle to the other vehicles in the formation, in lateral and/ or longitudinal directions, and determine that the measured distance is situated within a predetermined threshold interval, an advice may be outputted to the driver/-s of the vehicle/ -s in order to maintain the formation.

Other advantages and additional novel features will become apparent from the subsequent detailed description.

FIGURES Embodiments of the invention will now be described in further detail with reference to the accompanying figures, in which: Figure 1A illustrates a side view of a vehicle formation according to an embodiment; Figure 1B illustrates a vehicle formation according to an embodiment, seen from above; Figure 1C illustrates a vehicle formation according to an embodiment, seen from above; Figure 2 illustrates a vehicle interior according to an embodiment; Figure 3 is a flow chart illustrating an embodiment of the method; Figure 4 is an illustration depicting a system according to an embodiment.

DETAILED DESCRIPTION Embodiments of the invention described herein are defined as a control unit and a method in a control unit, which may be put into practice in the embodiments described below. These embodiments may, however, be exemplified and realised in many different forms and are not to be limited to the examples set forth herein; rather, these illustrative examples of embodiments are provided so that this disclosure will be thorough and complete.

Still other objects and features may become apparent from the following detailed description, considered in conjunction with the accompanying drawings. It is to be understood, however, that the drawings are designed solely for purposes of illustration and not as a definition of the limits of the herein disclosed embodiments, for which reference is to be made to the appended claims. Further, the drawings are not necessarily drawn to scale and, unless otherwise indicated, they are merely intended to conceptually illustrate the structures and procedures described herein.

Figure 1 illustrates a scenario wherein a plurality of vehicles 101, 102 is driving in a formation 100 in a direction 105.

The vehicles 101, 102 are coordinated and organised in the formation 100, e.g. in order to perform a common assignment on an underlay such as an airstrip, a road, an agricultural area, etc. The formation 100 may comprise any arbitrary number of vehicles 101, 102 exceeding one.

Such assignment may comprise e.g. snowploughing of a landing strip, as previously discussed. For performing tasks like snowploughing, the vehicles 101, 102 proceed in the organised formation 100. Further, at least some of the vehicles 101, 102 in the formation 100 may comprise an instrument 110, 120 in order to perform the common assignment, in some embodiments. Such instrument 110, 120 may comprise e.g. a snowplough, a grader, a farming tool, an irrigation device, a construction equipment, a roller, a lawn mower, a harvesting device and/ or a cleaning device, or similar.

Errors in the alignment when performing snowploughing would result in a low quality outcome for the snowploughing procedure, due to a gap that is created between the instruments 110, 120, which could result in the need of redoing the whole operation from scratch. Therefore, accurate positioning of the vehicles 101, 102 in relation to each other with the formation 100 is important. In case the vehicles 101, 102 are laterally positioned too close in relation to each other, thereby creating an unnecessary large overlap between the instruments 110, 120, the assignment/ snowploughing is not optimally performed. It may be required to use more vehicles 101, 102 in the formation 100, or alternatively pass the landing strip more times, thereby creating additional costs and/ or delay.

According to some embodiments, it may be required to position the formation 100, and thereby also the vehicles 101, 102 comprised in the formation 100 in relation to a set of landmarks 130-1, 130-2, 130-3. The set of landmarks 130-1, 130-2, 130-3 may comprise any arbitrary number of landmarks such as one, two, three, etc. An advantage with having additional landmarks 130-1, 130-2, 130-3 is that redundancy is provided. It may thereby be possible to position the formation 100 also when one of the landmarks 130-1, 130-2, 130-3 is temporary unsighted, e.g. hidden behind another vehicle 101, 102, etc.

Accurate positioning can be obtained by relative positioning of the vehicles 101, 102 with respect to the set of landmarks 130-1, 130-2, 130-3 which may be detected with one or more on-board sensors 140. Such on-board sensor 140 may comprise e.g. a radar, a lidar, a camera, a stereo camera, an infrared camera, a video camera, an ultrasound device, a time-offlight camera, or similar device, in different embodiments. Also, a combination of a plurality of sensors 140 may be utilised. The sensor 140 in the vehicles 101, 102 may be comprised in the vehicles 101, 102 for various other reasons, besides the herein described.

The various sensors 140 in the vehicles 101, 102 may be used for localising other vehicles 101, 102 in the formation 100, as well as localising the formation 100 in relation to the set of landmarks 130-1, 130-2, 130-3, possibly in combination with a Simultaneous Localisation And Mapping (SLAM) type algorithm.

Using these sensors 140, the other vehicles 101, 102 in the formation 100 can eventually be tracked for increasing the accuracy of the relative localisation of the vehicles 101, 102 in the formation 100. Tracking other vehicles 101, 102 can also constitute a redundancy mechanism in case a subset of landmarks 130-1, 130-2, 130-3 is occluded by other vehicles 101, 102 in the formation 100. Vehicles 101, 102 can eventually be equipped with reflectors that facilitate their detections, as will be further illustrated in Figure 1C.

In some embodiments, the optional landmarks 130-1, 130-2, 130-3 may comprise a respective reflector 135-1, 135-2, 135-3 for facilitating the detection, also in difficult conditions for the sensor 140 such as fog, heavy snow, rain, hailstorm, etc.

The optional set of landmarks 130-1, 130-2, 130-3 may be situated at pre-known geographical positions, such as e.g. at the extreme ends of the airstrip, road, agricultural area or other area that is to be treated by the vehicles 101, 102 in the formation 100. By determining the distance from the sensor 140 of the vehicle 101 to each individual landmark 130-1, 130-2, 130-3, such as e.g. at least three landmarks 130-1, 130-2, 130-3, the current geographical position of the vehicle 101 in the formation 100, comprising the sensor 140 may be unambiguously determined based on triangulation, trilateration, triangulateration, etc.

In some embodiments, the vehicles 101, 102 may comprise for example agricultural machineries, e.g. combine harvesters, tractors; or construction machines, e.g. bulldozers, graders, road rollers; minesweepers; lawn movers; cleaning devices, etc.

The vehicles 101, 102 in the formation 100 may comprise vehicles of the same, or different types in different embodiments. The vehicles 101, 102 may be driver controlled or driverless autonomously controlled vehicles in different embodiments. However, for enhanced clarity, the vehicles 101, 102 are subsequently described as having a driver, at least in one of the vehicles 101, 102.

An advantage with the provided optional solution based on localisation of landmarks 130-1, 130-2, 130-3 is that there is no need for expensive localisation devices on every vehicle 101, 102 in the formation 100. Thereby money is saved.

In case the vehicles 101, 102, or at least some vehicle 101, 102 in the formation 100 comprises a localisation system, e.g. based on a satellite navigation system such as the Navigation Signal Timing and Ranging (Navstar) Global Positioning System (GPS), Differential GPS (DGPS), Galileo, GLONASS, or the like, a trustful localisation may be made. Further, in case both localisation of landmarks 130-1, 130-2, 130-3 in addition to the localisation system is made, redundancy is created. Thereby, an improved and more robust localisation is achieved.

The vehicles 101, 102 in the formation 100 may intercommunicate and thereby be coordinated via a wireless signal. Such wireless signal may comprise, or at least be inspired by wireless communication technology such as Wi-Fi, Wireless Local Area Network (WLAN), Ultra Mobile Broadband (UMB), Bluetooth (BT), Near Field Communication (NFC), Radio-Frequency Identification (RFID), optical communication such as Infrared Data Association (IrDA) or infrared transmission to name but a few possible examples of wireless communications in some embodiments.

In some embodiments, the communication between vehicles 101, 102 in the formation 100 may be performed via Vehicle-to-Vehicle (V2V) communication, e.g. based on Dedicated Short-Range Communications (DSRC) devices. DSRC works in 5.9 GHz band with bandwidth of 75 MHz and approximate range of 1000 m in some embodiments.

The wireless communication may be made according to any IEEE standard for wireless vehicular communication like e.g. a special mode of operation of IEEE 802.11 for vehicular networks called Wireless Access in Vehicular Environments (WAVE). IEEE 802.11 p is an extension to 802.11 Wireless LAN medium access layer (MAC) and physical layer (PHY) specification.

The communication may alternatively be made over a wireless interface comprising, or at least being inspired by radio access technologies such as e.g. 3GPP LTE, LTE-Advanced, E-UTRAN, UMTS, GSM, GSM/ EDGE, WCDMA, Time Division Multiple Access (TDMA) networks, Frequency Division Multiple Access (FDMA) networks, Orthogonal FDMA (OFDMA) networks, Single-Carrier FDMA (SC-FDMA) networks, Worldwide Interoperability for Microwave Access (WiMax), or Ultra Mobile Broadband (UMB), High Speed Packet Access (HSPA) Evolved Universal Terrestrial Radio Access (E-UTRA), Universal Terrestrial Radio Access (UTRA), GSM EDGE Radio Access Network (GERAN), 3GPP2 CDMA technologies, e.g., CDMA2000 1x RTT and High Rate Packet Data (HRPD), or similar, just to mention some few options, via a wireless communication network.

In some alternative embodiments, the landmarks 130-1, 130-2, 130-3 and/ or the vehicles 101, 102 may emit a wireless beaconing signal, which may be received by the sensor 140 in the vehicle 101 and utilised for determining distance and/ or direction between the landmark 130-1, 130-2, 130-3/ vehicles 101, 102 and the sensor 140.

Figure 1B illustrates the formation 100 of vehicles 101, 102 as illustrated in Figure 1A as seen from above.

The lateral displacement distance 150 between a first vehicle 101 of the formation 100 and another vehicle 102 may be determined, based on the sensor 140.

In some embodiments, the lateral displacement distance 150 may be determined by determining a direct distance between the sensor 140 of the vehicle 101 to the other vehicle 102, or a specific part thereof, and an angle of direction from the sensor 140 to said part of the other vehicle 102. By trigonometric computations, the distance in lateral and/ or longitudinal direction to the other vehicle 102, in the direction of travel 105, may be calculated.

In case the sensor 140 comprises a radar, electromagnetic waves in the radio or microwaves domain are generated and transmitted via an antenna. Return signals from objects in the path of the emitted signal are then captured and a detection of the other vehicle 102, or a particular part thereof may be made. The sensor 140 may comprise a lidar, having about the same concept as the radar, but operating within other parts of the electromagnetic spectrum such as ultraviolet, visible, or near infrared light emitted by a laser, rather than radio waves.

Further, a lateral displacement threshold interval 160, 170 may be defined or configured. Said interval may comprise a lower lateral displacement threshold limit 160 and an upper lateral displacement threshold limit 170. The lower lateral displacement threshold limit 160 may be a lateral distance where the overlap of the instruments 110, 120 of the respective vehicles 101, 102 becomes too large for the assignment to be effective; and/ or when the lateral distance becomes so short that it becomes dangerous. The upper lateral displacement threshold limit 170 may be a lateral distance where a gap is created between the respective instruments 110, 120 of the vehicles 101, 102; or where the lateral distance between the vehicles 101, 102 of the formation 100 becomes so large that the assignment cannot be performed with sufficient quality. The lower lateral displacement threshold limit 160 and the upper lateral displacement threshold limit 170 may have the same value in some embodiments.

When the determined lateral displacement distance 150 is within the lateral displacement threshold interval 160, 170, the formation 100 is considered kept in the lateral direction between the vehicles 101,102.

When the determined lateral displacement distance 150 is shorter than the lower lateral displacement threshold limit 160, the vehicles 101, 102 may be adjusted laterally in relation to each other in order to increase the lateral displacement distance 150 in order to keep it within the lateral displacement threshold interval 160, 170. Correspondingly, when the determined lateral displacement distance 150 exceeds the upper lateral displacement threshold limit 170, the vehicles 101, 102 may be adjusted laterally in relation to each other in order to decrease the lateral displacement distance 150 in order to keep it within the lateral displacement threshold interval 160, 170.

Figure 1C illustrates the formation 100 of vehicles 101, 102 as illustrated in Figure 1A and/ or Figure 1B as seen from above.

In the illustrated embodiment, the other vehicle 102 is equipped with a reflector 180. Thereby, the other vehicle 102 a particular part of the other vehicle 102 may easily be detected by the sensor 140 of the vehicle 101, also in rough sensor conditions such as snow, darkness, rain, etc.

A longitudinal displacement distance 190 between a first vehicle 101 of the formation 100 and another vehicle 102, or particular part of the other vehicle 102 may be determined, based on the sensor 140.

In some embodiments, the longitudinal displacement distance 190 may be determined by determining a direct distance between the sensor 140 of the vehicle 101 to the other vehicle 102, or a specific part thereof, and an angle of direction from the sensor 140 to said part of the other vehicle 102. By trigonometric computations, the distance in longitudinal and/ or lateral direction to the other vehicle 102, in the direction of travel 105, may be calculated.

Further, a longitudinal displacement threshold interval 191, 192 may be defined or configured. Said interval may comprise a lower longitudinal displacement threshold limit 191 and an upper longitudinal displacement threshold limit 192. The lower longitudinal displacement threshold limit 191 may be the longitudinal distance 190 between the vehicles 101, 102 which is so short that it may present a traffic safety problem.

The upper longitudinal displacement threshold limit 192 may be a longitudinal distance where a gap is created between the respective instruments 110, 120 of the vehicles 101, 102; or where the longitudinal distance between the vehicles 101, 102 of the formation 100 becomes so large that the assignment cannot be performed with sufficient quality. The lower longitudinal displacement threshold limit 191 and the upper longitudinal displacement threshold limit 192 may have the same value in some embodiments.

When the determined longitudinal displacement distance 190 is within the longitudinal displacement threshold interval 191, 192, the formation 100 is considered kept in the longitudinal direction between the vehicles 101, 102.

When the determined longitudinal displacement distance 190 is shorter than the lower longitudinal displacement threshold limit 191, the vehicles 101, 102 may be adjusted longitudinally in relation to each other in order to increase the longitudinal displacement distance 190 in order to keep it within the longitudinal displacement threshold interval 191, 192. Correspondingly, when the determined longitudinal displacement distance 190 exceeds the upper longitudinal displacement threshold limit 192, the vehicles 101, 102 may be adjusted longitudinally in relation to each other in order to decrease the longitudinal displacement distance 190 in order to keep it within the longitudinal displacement threshold interval 191,192.

Figure 2 illustrates an example of a scenario as illustrated in any of Figure 1A, Figure 1 B and/ or Figure 1 C, as it may be perceived by the driver of the vehicle 101 when driving in the formation 100.

The vehicle 101 comprises a control unit 210. The control unit 210 is a computational device for facilitating for the driver of the vehicle 101 to maintain the formation 100 and optionally localisation of the formation 100 in relation to the set of landmarks 130-1, 130-2, 130-3 in some embodiments. The control unit 210 may receive signals over a wired or wireless communication interface, e.g. as any of the previously discussed, from the sensor 140 of the vehicle 101.

Based on the received sensor detection values and computations, the lateral distance 150 and/ or longitudinal distance 190 between the vehicles 101, 102. Further, the position of the formation may be determined based on determined distances to the set of landmarks 130-1, 130-2, 130-3 in some embodiments.

The result of the measurements and calculations may be outputted to the driver of the vehicle 101, e.g. on a display 220, and/ or a loudspeaker 230 in some embodiments, or some other output unit such as e.g. a display, a loudspeaker, a projector, a head-up display, a display integrated in the windshield of the vehicle 100, a display integrated in the dashboard of the vehicle 100, a tactile device, a portable device of the vehicle driver/ owner, intelligent glasses of the vehicle driver/ owner, etc.; or a combination thereof. In case the vehicle 101 comprises a display 220, information related to the measurements, calculations and formation positioning may be outputted graphically and/ or by text messages, in different embodiments.

In some embodiments, the result of the distance measurements and the position of the formation 100 may be outputted also to other vehicles 102 in the formation 100. Thereby, the driver of the other vehicles 102 becomes aware of the position of the formation 100 and the relative distance between the vehicles 101, 102 and may take measures to adjust the distance.

Thereby, the driver/s may be warned from diverging with the respective vehicle 101, 102 from a desired or predetermined position within the formation 100.

The vehicle 101 may in addition, or alternatively, comprise a haptic interface, for haptic communication with the driver, e.g. via a tactile device in the driving chair or other vehicle part in physical contact with the driver, warning him/ her from driving too close/ remote from the other vehicle 102, in some embodiments.

Thus, when the lateral displacement threshold interval 160, 170 and/ or the longitudinal displacement threshold interval 191, 192 is/ are exceeded, a warning message may be outputted to the driver, e.g. by presentation on the display 220, e.g. by using different colours; by an audio signal; by a haptic signal and/ or a combination of these alerting methods.

In some embodiments, the vehicle 101, 102 may further comprise a positioning unit in the vehicle 101, 102, which may be based on a satellite navigation system such as the Navigation Signal Timing and Ranging (Navstar) Global Positioning System (GPS), Differential GPS (DGPS), Galileo, GLONASS, or the like. An advantage therewith may be that redundancy is created for determining position of the formation 100; and/ or a more precise positioning of the formation 100 may be made.

Figure 3 illustrates an example of a method 300 according to an embodiment. The flow chart in Figure 3 shows the method 300 in a control unit 110. The control unit 110 may in some embodiments be comprised in a vehicle 101, comprised in a formation 100 of coordinated vehicles 101, 102.

The method 300 aims at maintaining the formation 100 comprising a plurality of laterally displaced vehicles 101, 102. According to some alternative embodiments, the method 300 also aims at localisation of the formation 100 in relation to a set of landmarks 130-1, 130-2, 130-3.

The vehicles 101, 102 in the formation 100 may be any arbitrary kind of means for conveyance of the same or different kind. However, in some particular embodiments, the vehicles 101, 102 may be vehicles for performing a common assignment. The vehicles 101, 102 may communicate with each other via wireless signals transmitted on any of the previously mentioned wireless interfaces, or e.g. by infrared light.

In order to be able to maintain the formation 100, the method 300 may comprise a number of steps 301-307. However, some of these steps 301-307 may be performed solely in some alternative embodiments, like e.g. steps 303-307. Further, the described steps 301-307 may be performed in a somewhat different chronological order than the numbering suggests. The method 300 may comprise the subsequent steps: Step 301 comprises determining a lateral displacement distance 150 of at least one other vehicle 102 in the formation 100, in relation to the vehicle 101, via a sensor 140.

Such sensor 140 may be based on electromagnetic radiation such as e.g. radar. However, such detection may alternatively be made by visual detection made by a camera, in combination with an image recognition program; by a sensor based on infra-red light, laser or micro waves; and/ or by a tomographic motion detection system based on detection of radio wave disturbances, in different embodiments.

The relative lateral displacement distance 150 of the other vehicle 102 may be determined by detecting a reflected sensor signal of a reflector 180 of the other vehicle 102.

Step 302 comprises adjusting the lateral position of the vehicle 101 in relation to the other vehicle 102, when the determined 301 lateral displacement distance 150 is outside a lateral threshold interval 160, 170.

The adjustment may be made in order to place the lateral position of the vehicle 101 within the lateral threshold interval 160, 170.

Step 303, which may be performed only in some embodiments, comprises determining a distance to each landmark 130-1, 130-2, 130-3 comprised in the set of landmarks 130-1, 130-2, 130-3.

The distance to each landmark 130-1, 130-2, 130-3 comprised in the set of landmarks 130-1, 130-2, 130-3 may be determined by detecting a reflected sensor signal of a reflector 135-1, 135-2, 135-3 of the respective landmark 130-1, 130-2, 130-3.

Step 304, which may be performed only in some embodiments, comprises localising the formation 100 in relation to the set of landmarks 130-1, 130-2, 130-3, based on the determined 303 distances.

Step 305, which may be performed only in some embodiments wherein the vehicles 101, 102 comprised in the formation 100 also are longitudinal displaced in relation to each other, comprises determining a longitudinal displacement distance 190 of at least one other vehicle 102 in the formation 100, in relation to the vehicle 101, via the sensor 140.

The relative longitudinal displacement distance 190 of the other vehicle 102 is determined by detecting a reflected sensor signal of a reflector 180 of the other vehicle 102.

Step 306, which may be performed only in some embodiments wherein step 305 has been performed, comprises adjusting the longitudinal position of the vehicle 101 in relation to the other vehicle 102, when the determined 305 longitudinal displacement distance 190 is outside a longitudinal threshold interval 191, 192.

Step 307, which may be performed only in some embodiments, comprises instructing the other vehicle 102 to adjust its lateral position, based on the determined 301 lateral displacement distance 150 when the determined 301 lateral displacement distance 150 is outside the lateral threshold interval 160, 170 and/ or to adjust its longitudinal position, based on the determined 305 longitudinal displacement distance 190 when the determined 305 longitudinal displacement distance 190 is outside the longitudinal threshold interval 191, 192, via wireless communication, e.g. any of the previously discussed wireless communication interfaces.

Figure 4 presents a system 400. The system 400 aims at maintaining a formation 100 comprising a plurality of laterally displaced vehicles 101, 102. Further, the system 400, in some alternative embodiments, may comprise localisation of the formation 100 in relation to a set of landmarks 130-1, 130-2, 130-3.

The system 400 comprises a control unit 210 for performing the method 300 according to any of the previously described steps 301-307 as described above and illustrated in Figure 3. Thus the control unit 210 aims at maintaining a formation 100 comprising a plurality of laterally displaced vehicles 101, 102. In some embodiments, the control unit 210 also may aim at localisation of the formation 100 in relation to a set of landmarks 130-1, 130-2, 130-3.

The control unit 210 is configured to determine a lateral displacement distance 150 of at least one other vehicle 102 in the formation 100, in relation to the vehicle 101, via a sensor 140. The control unit 210 is also configured to generate a command signal to adjust the lateral position of the vehicle 101 in relation to the other vehicle 102, when the determined lateral displacement distance 150 is outside a lateral threshold interval 160, 170. Furthermore, the control unit 210 may be configured, in some embodiments, to determine a distance to each landmark 130-1, 130-2, 130-3 comprised in the set of landmarks 130-1, 130-2, 130-3. The control unit 240 may also be configured to localise the formation 100 in relation to the set of landmarks 130-1, 130-2, 130-3, based on the determined distances.

The control unit 210 may in some embodiments, wherein the vehicles 101, 102 comprised in the formation 100 also are longitudinal displaced in relation to each other, be further configured to determine a longitudinal displacement distance 190 of at least one other vehicle 102 in the formation 100, in relation to the vehicle 101, via the sensor 140. Furthermore, such control unit 210 may be alternatively configured to generate a command signal to adjust the longitudinal position of the vehicle 101 in relation to the other vehicle 102, when the determined longitudinal displacement distance 190 is outside a longitudinal threshold interval 191, 192.

Further, in some alternative embodiments, the control unit 210 may be configured to instruct the other vehicle 102 to adjust its lateral position, based on the determined lateral displacement distance 150 when the determined lateral displacement distance 150 is outside the lateral threshold interval 160, 170 and/ or adjust its longitudinal position, based on the determined longitudinal displacement distance 190 when the determined longitudinal displacement distance 190 is outside the longitudinal threshold interval 191, 192, via wireless communication.

In some embodiments, the control unit 210 may be configured to determine the relative lateral and/ or longitudinal displacement distance 150, 190 of the other vehicle 102 by detecting a reflected sensor signal of a reflector 180 of the other vehicle 102.

Further, according to some embodiments, the control unit 210 may also be configured to determine the relative lateral and/ or longitudinal displacement distance 150, 190 of the other vehicle 102 via a plurality of sensors 140 in the vehicle 101 of the same or different types, such as e.g. any of the previously enumerated.

Also, the control unit 210 may be configured to determine the distance to each landmark 130-1, 130-2, 130-3 comprised in the set of landmarks 130-1, 130-2, 130-3 by detecting a reflected sensor signal of a reflector 135-1, 135-2, 135-3 of the respective landmark 130-1, 130-2, 130-3.

The control unit 210 may further be configured to determine the distance to each landmark 130-1, 130-2, 130-3 comprised in the set of landmarks 130-1, 130-2, 130-3 via a plurality of sensors 140 in the vehicle 101 of the same or different types, such as e.g. any of the previously enumerated.

Also, the system 400 according to some embodiments may also comprise a display 220, a loudspeaker 230, a tactile device or any other informational device.

The control unit 210 may comprise a receiver 410 configured for receiving information from the sensor 140 concerning other vehicles 102 in the formation and landmarks 130-1, 130-2, The control unit 210 further may comprise a processor 420 configured for performing various calculations for conducting the method 300 according to at least some of steps 301-307.

Such processor 420 may comprise one or more instances of a processing circuit, i.e. a Central Processing Unit (CPU), a processing unit, an Application Specific Integrated Circuit (ASIC), a microprocessor, or other processing logic that may interpret and execute instructions. The herein utilised expression “processor” may thus represent a processing circuitry comprising a plurality of processing circuits, such as, e.g., any, some or all of the ones enumerated above.

Furthermore, the control unit 210 may comprise an optional memory 425 in some embodiments. The optional memory 425 may comprise a physical device utilised to store data or programs, i.e., sequences of instructions, on a temporary or permanent basis. According to some embodiments, the memory 425 may comprise integrated circuits comprising siliconbased transistors. The memory 425 may comprise e.g. a memory card, a flash memory, a USB memory, a hard disc, or another similar volatile or non-volatile storage unit for storing data such as e.g. ROM (Read-Only Memory), PROM (Programmable Read-Only Memory), EPROM (Erasable PROM), EEPROM (Electrically Erasable PROM), etc. in different embodiments.

Further, the control unit 210 may comprise a signal transmitter 430. The signal transmitter 430 may be configured for transmitting a signal to be received by the display 220 in the vehicle 101, and/ or displays in other vehicles 102 in the formation 100.

The previously described steps 301-307 to be performed in the control unit 210 may be implemented through the one or more processors 420 within the control unit 210, together with a computer program comprising instructions for performing at least some of the functions of the steps 301-307. Thus a computer program, comprising instructions for performing the steps 301 -307 in the control unit 210 may perform the method 300 comprising at least some of the steps 301-307 for maintaining a formation 100 comprising a plurality of laterally displaced vehicles 101, 102, and localisation of the formation 100 in relation to a set of landmarks 130-1, 130-2, 130-3, when the computer program is executed by the one or more processors 420 of the control unit 210.

The described steps 301-307 thus may be performed by a computer algorithm, a machine executable code, a non-transitory computer-readable medium, or a software instructions programmed into a suitable programmable logic such as the processor 420 in the control unit 210.

The computer program product mentioned above may be provided for instance in the form of a data carrier carrying computer program code for performing at least some of the step 301-307 according to some embodiments when being loaded into the one or more processors 420 of the control unit 210. The data carrier may be, e.g., a hard disk, a CD ROM disc, a memory stick, an optical storage device, a magnetic storage device or any other appropriate medium such as a disk or tape that may hold machine readable data in a non-transitory manner. The computer program product may furthermore be provided as computer program code on a server and downloaded to the control unit 210 remotely, e.g., over an Internet or an intranet connection.

Further, some embodiments may comprise a vehicle 101, 102, comprising the control unit 210, as described above, for performing the method 300 according to at least some of the described steps 301-307.

The terminology used in the description of the embodiments as illustrated in the accompanying drawings is not intended to be limiting of the described method 300, control unit 210; computer program, and/ or system 400. Various changes, substitutions and/ or alterations may be made, without departing from invention embodiments as defined by the appended claims.

As used herein, the term "and/ or" comprises any and all combinations of one or more of the associated listed items. The term “or” as used herein, is to be interpreted as a mathematical OR, i.e., as an inclusive disjunction; not as a mathematical exclusive OR (XOR), unless expressly stated otherwise. In addition, the singular forms "a", "an" and "the" are to be interpreted as “at least one”, thus also possibly comprising a plurality of entities of the same kind, unless expressly stated otherwise. It will be further understood that the terms "includes", "comprises", "including" and/ or "comprising", specifies the presence of stated features, actions, integers, steps, operations, elements, and/ or components, but do not preclude the presence or addition of one or more other features, actions, integers, steps, operations, elements, components, and/ or groups thereof. A single unit such as e.g. a processor may fulfil the functions of several items recited in the claims. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. A computer program may be stored/ distributed on a suitable medium, such as an optical storage medium or a solid-state medium supplied together with or as part of other hardware, but may also be distributed in other forms such as via Internet or other wired or wireless communication system.

Claims

1. A method (300) in a control unit (210) of a vehicle (101), for maintaining a formation (100) comprising a plurality of laterally displaced vehicles (101, 102); the vehicles in the formation being coordinated to perform a common assignment on an underlay, which method (300) comprises: determining (301) a lateral displacement distance (150) of at least one other vehicle (102) in the formation (100), in relation to the vehicle (101), via a sensor (140); and adjusting (302) the lateral position of the vehicle (101) in relation to the other vehicle (102), when the determined (301) lateral displacement distance (150) is outside a lateral threshold interval (160, 170).

2. The method (300) according to claim 1 , wherein the vehicles (101, 102) comprised in the formation (100) also are longitudinally displaced in relation to each other; and wherein the method (300) further comprises: determining (305) a longitudinal displacement distance (190) of at least one other vehicle (102) in the formation (100), in relation to the vehicle (101), via the sensor (140); and adjusting (306) the longitudinal position of the vehicle (101) in relation to the other vehicle (102), when the determined (305) longitudinal displacement distance (190) is outside a longitudinal threshold interval (191, 192).

3. The method (300) according to any of claim 1 or claim 2, further comprising: instructing (307) the other vehicle (102) to adjust its lateral position, based on the determined (301) lateral displacement distance (150) when the determined (301) lateral displacement distance (150) is outside the lateral threshold interval (160, 170) and/ or to adjust its longitudinal position, based on the determined (305) longitudinal displacement distance (190) when the determined (305) longitudinal displacement distance (190) is outside the longitudinal threshold interval (191, 192), via wireless communication.

4. The method (300) according to any of claims 1 -3 wherein the relative lateral and/ or longitudinal displacement distance (150, 190) of the other vehicle (102) is determined (301 , 305) by detecting a reflected sensor signal of a reflector (180) of the other vehicle (102).

5. The method (300) according to any of claims 1-4, for localisation of the formation (100) in relation to a set of landmarks (130-1, 130-2, 130-3), further comprising: determining (303) a distance to each landmark (130-1, 130-2, 130-3) comprised in the set of landmarks (130-1, 130-2, 130-3); and localising (304) the formation (100) in relation to the set of landmarks (130-1, 130 2, 130-3), based on the determined (303) distances.

6. The method (300) according to claim 5 wherein the distance to each landmark (130-1 , 130-2, 130-3) comprised in the set of landmarks (130-1, 130-2, 130-3) is determined (303) by detecting a reflected sensor signal of a reflector (135-1 , 135-2, 135-3) of the respective landmark (130-1, 130-2, 130-3).

7. A control unit (210) in a vehicle (101 ), arranged to maintain a formation (100) comprising a plurality of laterally displaced vehicles (101, 102), the vehicles in the formation being coordinated to perform a common assignment on an underlay, wherein the control unit (210) is configured to: determine a lateral displacement distance (150) of at least one other vehicle (102) in the formation (100), in relation to the vehicle (101), via a sensor (140); and generate a command signal to adjust the lateral position of the vehicle (101) in relation to the other vehicle (102), when the determined lateral displacement distance (150) is outside a lateral threshold interval (160, 170).

8. The control unit (210) according to claim 7, wherein the vehicles (101, 102) comprised in the formation (100) also are longitudinally displaced in relation to each other; further configured to: determine a longitudinal displacement distance (190) of at least one other vehicle (102) in the formation (100), in relation to the vehicle (101), via the sensor (140); and generate a command signal to adjust the longitudinal position of the vehicle (101) in relation to the other vehicle (102), when the determined longitudinal displacement distance (190) is outside a longitudinal threshold interval (191, 192).

9. The control unit (410) according to any of claim 7 or claim 8, further configured to: instruct the other vehicle (102) to adjust its lateral position, based on the determined lateral displacement distance (150) when the determined lateral displacement distance (150) is outside the lateral threshold interval (160, 170) and/ or adjust its longitudinal position, based on the determined longitudinal displacement distance (190) when the determined longitudinal displacement distance (190) is outside the longitudinal threshold interval (191,192), via wireless communication.

10. The control unit (410) according to any of claims 7-9, further configured to: determine the relative lateral and/ or longitudinal displacement distance (150, 190) of the other vehicle (102) by detecting a reflected sensor signal of a reflector (180) of the other vehicle (102).

11. The control unit (410) according to any of claims 7-10, further configured to: determine the relative lateral and/ or longitudinal displacement distance (150, 190) of the other vehicle (102) via a plurality of sensors (140) in the vehicle (101).

12. The control unit (410) according to any of claims 7-11, further configured to localise the formation (100) of the vehicles (101, 102) in relation to a set of landmarks (130-1, 130-2, 130-3): determine a distance to each landmark (130-1, 130-2, 130-3) comprised in the set of landmarks (130-1, 130-2, 130-3); and localise the formation (100) in relation to the set of landmarks (130-1, 130-2, 130-3), based on the determined distances.

13. The control unit (410) according to claim 12, further configured to: determine the distance to each landmark (130-1, 130-2, 130-3) comprised in the set of landmarks (130-1, 130-2, 130-3) by detecting a reflected sensor signal of a reflector (135-1, 135-2, 135-3) of the respective landmark (130-1, 130-2, 130-3).

14. The control unit (410) according to any of claims 7 - 13, wherein the vehicles of the formation are provided with instruments to perform the common assignment and wherein said instruments comprises a snowplough or a farming tool.

15. A computer program comprising instructions which, when the computer program is executed by the control unit (410), according to any of claims 7-14, cause the control unit (410) to carry out the method (500) according to any of claims 1 -6.