Improved vehicle platooning

Abstract

Method for operating a vehicle convoy (10) with at least three vehicles (11, 12, 13), wherein a first safety distance (S1) from the first vehicle (11) is set by a second vehicle (12) and a second safety distance (S2) from the second vehicle (12) is set by at least one third vehicle (13) immediately following the second vehicle (12), and / or a second safety distance (S2) is set between at least two third vehicles (13) following the second vehicle (12), wherein communication links are set up between control units (21, 22, 23) for the longitudinal guidance and / or transverse guidance of the vehicles (11, 12, 13) in order to adapt the longitudinal guidance and / or transverse guidance of the second vehicle (12) and of the at least one third vehicle (13) to the first vehicle (11), wherein when a braking operation of the vehicle convoy (10) is initiated, the vehicles (11, 12,13) into a sinusoidal trajectory (20).

Description

[0001] The invention relates to a method for operating a vehicle convoy consisting of at least three vehicles, in which a first safety distance from the first vehicle is set by a second vehicle and a second safety distance from the second vehicle and / or a third vehicle is set by at least a third vehicle. Furthermore, the invention relates to a vehicle convoy.

[0002] So-called platooning, or driving in a convoy, is currently only being used on an experimental scale, but it does enable additional energy savings. The theoretical energy savings can be realized in the form of fuel savings or a reduction in electrical energy consumption and depend not only on the frontal area or the drag coefficient of the vehicles, but also on the distance between the vehicles in the convoy. Ideally, the distance between the vehicles in the convoy should be as short as possible. The vehicles can be linked via an electronic drawbar and thus communicate with each other in real time to transmit steering and braking commands. This communication can be implemented via ADAS systems and car2X communication.

[0003] The choice of distance between vehicles in a convoy represents a compromise between safety against rear-end collisions and energy savings. The distance between vehicles in a convoy must be set as small as possible to maximize the energy savings from slipstreaming. However, an emergency braking by the lead vehicle must under no circumstances result in rear-end collisions with the following vehicles.

[0004] JP 2013 - 67 302 A describes a system and method for controlling vehicles following a lead vehicle. The vehicles establish a communication link to coordinate convoy travel. Before establishing the communication link, the vehicles may travel in different lanes to avoid a rear-end collision.

[0005] DE 10 2019 214 121 A1 discloses a method in which an adaptive cruise control assistant is modified for a convoy scenario.

[0006] DE 10 2017 009 306 A1 describes a method for arranging vehicles in a vehicle convoy and a control arrangement for carrying out the method.

[0007] It is the object of the present invention to provide a method by which a vehicle convoy can perform a braking maneuver with optimized safety reserves.

[0008] According to the invention, this object is achieved by a method having the features of claim 1 and a vehicle convoy having the features of claim 9. Advantageous embodiments and further developments emerge from the dependent claims.

[0009] According to one aspect of the invention, a method for operating a vehicle convoy consisting of at least three vehicles is provided. In one step, a second vehicle sets a first safety distance from the first vehicle, and at least one third vehicle sets a second safety distance from the second vehicle and / or from a third vehicle.

[0010] Advantageously, the first vehicle can also be a leading vehicle or a lead vehicle of the vehicle convoy. The second vehicle can be a vehicle immediately following the first vehicle. The at least one third vehicle can continue to follow the second vehicle or a leading third vehicle or be positioned behind it in the vehicle convoy.

[0011] In a further step, communication links are established between control units for the longitudinal and / or lateral guidance of the vehicles in order to adapt the longitudinal and / or lateral guidance of the second vehicle and the at least one third vehicle to the first vehicle. Depending on the configuration, a control unit of the first vehicle can also issue control commands to adjust the first safety distance to the immediately following second vehicle.

[0012] In one step, when the vehicle convoy initiates a braking process, the vehicles are adjusted to a sinusoidal trajectory.

[0013] According to a further aspect of the invention, a vehicle convoy is provided which is configured to carry out a method according to the invention. The vehicle convoy comprises a first vehicle, which leads the vehicle convoy or is a lead vehicle of the vehicle convoy. A second vehicle immediately follows the first vehicle at a first safety distance. The vehicle convoy further comprises at least one third vehicle, which follows the second vehicle.

[0014] A second safety distance is set between the second vehicle and a third vehicle immediately following the at least one third vehicle. The vehicle convoy may comprise a plurality of third vehicles positioned following the second vehicle in the vehicle convoy, between each of which the second safety distance is set. The respective vehicles in the vehicle convoy may be identical or the same vehicles or different vehicles. In particular, the vehicles may have different dimensions and masses.

[0015] By adjusting the sinusoidal trajectory, the vehicles alternately approach the edges or lane boundaries within the possible lane width. This measure increases the braking distance in the event of a braking maneuver, especially an emergency braking maneuver. This can shorten the safety distances between vehicles in a convoy or increase road safety by increasing the braking distance reserve.

[0016] Depending on the configuration, the individual vehicles in the convoy exhibit a transverse and / or angular offset from one another when adjusting the sinusoidal trajectory. This measure can further increase the braking distance, as the individual vehicles in the convoy can brake past the vehicles ahead and thus avoid collisions caused by the offset. This also increases the braking distance, thus increasing road safety.

[0017] In one embodiment, the first safety distance is set greater than the second safety distance. This measure can compensate for the time delay in transmitting braking commands to the following vehicles in the vehicle convoy. If the control commands from the control unit of the first vehicle are transmitted to all following vehicles, all other safety distances can be reduced equally, since no time delay in transmitting control commands is to be expected between the third vehicles and between the second and third vehicles.

[0018] If, in an alternative embodiment, the control commands are transmitted from vehicle to vehicle, it may be advantageous to increase the second safety distances or at least to adapt them to the first safety distance.

[0019] According to a further embodiment, the braking process is initiated by the first vehicle and transmitted to the second vehicle and the at least one third vehicle via the communication connections. This allows the control unit of the first vehicle or the lead vehicle to be responsible for initiating braking processes.

[0020] According to a further embodiment, the first safety distance is set between 1 and 20 meters by the second vehicle and / or by the first vehicle. Advantageously, the first safety distance is set such that it includes a safety buffer to compensate for transmission delays in the communication connection. The first safety distance can thus result from a speed-dependent distance component, which is added to or multiplied by the safety buffer.

[0021] The speed-dependent distance component can, for example, be a distance which is calculated depending on the vehicle speed and at least one parameter or vehicle parameters, such as total mass, tire pressure, ambient temperature, weather, in order to steer the vehicle to a standstill without a collision with a vehicle in front of the vehicle convoy.

[0022] The safety buffer can be an absolute braking distance or distance calculated based on a current vehicle speed and a possible or usual latency of the communication connection.

[0023] Alternatively, the safety buffer can also be configured as a factor greater than 1, thus increasing the speed-dependent distance component to compensate for the latency of the communication connection. Such a safety buffer can be determined empirically, for example, and can depend on other parameters, such as sources of interference in the communication connection, the utilization of the communication connection, the time of day, and the like.

[0024] According to a further embodiment, when a braking maneuver is initiated, a sinusoidal trajectory of the vehicles in the convoy is adjusted, which has a wavelength of two vehicle lengths and two safety distances. This measure allows one vehicle to steer to the left edge of the lane, and a following and / or preceding vehicle to the right edge of the lane. In addition to increasing the braking distance due to cornering, this also allows an angular offset between the vehicles to be set, allowing a clear area in the lane to the side of the preceding vehicle to be used for braking in the event of an emergency braking maneuver.

[0025] According to a further embodiment, when a braking maneuver is initiated, in addition to the controlled safety distance, an angular offset between the vehicles in the convoy is used to extend the potential braking distance. This allows the lane to be used even more efficiently for braking the vehicles in the convoy.

[0026] According to a further embodiment, the control units of the second vehicle and the at least one third vehicle transmit vehicle lengths and / or vehicle masses to the control unit of the first vehicle in order to adapt at least one parameter of the sinusoidal trajectory. This allows for the accumulation of relevant data from the vehicles of the vehicle convoy in the control unit of the first vehicle and enables centralized trajectory planning, which is provided to the following vehicles of the vehicle convoy.

[0027] The sinusoidal trajectory used for braking can be calculated in advance and made available to all vehicles in the convoy to minimize the amount of data to be transmitted in the event of a braking maneuver. Advantageously, the sinusoidal trajectory can be recalculated at regular intervals.

[0028] Alternatively or additionally, changing lanes or roadways can be detected and used as a trigger to recalculate the sinusoidal trajectory.

[0029] According to a further embodiment, a lane width of a lane traveled by the vehicle convoy is measured by at least one sensor and / or received from a database. Preferably, the sinusoidal trajectory is adjusted by at least one control unit such that, at local maxima or minima of the sinusoidal trajectory, the vehicles are steered to one edge of the lane. At local maximums or minima of the sinusoidal trajectory, the vehicles are steered such that, at local maximums or minima of the sinusoidal trajectory, they do not travel laterally beyond the lane boundary or a lane edge.

[0030] The invention is illustrated schematically in the drawings using embodiments and will be further described with reference to the drawings. It shows: Fig. 1 a schematic plan view of a vehicle convoy to illustrate a method according to the invention according to an embodiment, and Fig. 2 a diagram illustrating a reduction in the distances between vehicles while maintaining the same safety distances.

[0031] In the figures, identical reference numerals refer to the same elements or structural components. The sizes and relative positions of the elements in the figures are not necessarily shown to scale. Some elements may, for example, be shown enlarged and positioned differently for clarity.

[0032] Fig. 1 shows a schematic plan view of a vehicle convoy 10 according to an exemplary embodiment of the invention. The vehicle convoy 10 is configured to carry out a method according to the invention. In particular, the method according to the invention will be explained in the context of the description of the vehicle convoy 10.

[0033] The vehicle convoy 10 has a first vehicle 11, which leads the vehicle convoy 10 or is a lead vehicle of the vehicle convoy 10. The first vehicle 11 is immediately followed by a second vehicle 12 at a first safety distance S1.

[0034] Furthermore, the vehicle convoy 10 has at least one third vehicle 13, which follows the second vehicle 12 or another third vehicle 13. In the illustrated embodiment, two third vehicles 13 are shown for the sake of clarity.

[0035] A second safety distance S2 is set between the second vehicle 12 and the at least one third vehicle 13. The same second safety distance S2 is also set between the two third vehicles 13.

[0036] The respective vehicles 11, 12, 13 in the vehicle convoy 10 can be identical or the same vehicles or different vehicles. In particular, the vehicles 11, 12, 13 can have different dimensions and masses.

[0037] When transmitting steering commands and braking commands for longitudinal and lateral guidance by control units 21, 22, 23 of vehicles 11, 12, 13, runtimes and latencies from the sensory detection of an obstacle in the leading vehicle 11 to the processing of the information, for example in the Electronic Braking System (EBS) by the control units or braking system actuators in the following vehicles 12, 13, must be taken into account when setting the safety distances S1, S2.

[0038] Since the control commands are transmitted simultaneously via communication links (not shown) between the control unit 21 of the first vehicle 11 and the control units 22, 23 of the following vehicles, the first safety distance S1 is set, for example, to be greater than the second safety distance S2.

[0039] The safety distances S1, S2 are defined exclusively in the longitudinal direction X and distance the respective vehicles 11, 12, 13 of the vehicle convoy 10 from each other. Fig. 1 shows the vehicle convoy 10 during an initiated braking maneuver, in which the vehicles 11, 12, 13 are adjusted to a sinusoidal trajectory 20. The air turbulence of the vehicles 11, 12, 13 is illustrated by way of example with the directions of travel (arrows).

[0040] By adjusting the sinusoidal trajectory 20, a vehicle 12 can steer to a left lane edge 31 and a following and / or preceding vehicle 11, 13 to a right lane edge 32. In addition to increasing the braking distance due to cornering, this also allows an angular offset between the vehicles 11, 12, 13 to be set, which allows a free area in the lane 30 to the side of the respective preceding vehicle 12, 11 to be used for braking in the event of an emergency braking maneuver.

[0041] When a braking operation is initiated, such a sinusoidal trajectory 20 of the vehicles 11, 12, 13 of the vehicle convoy 10 is adjusted, which forms a wavelength T from two consecutive vehicle lengths F1, F2 and two safety distances S1, S2. The corresponding vehicle lengths F1, F2 are connected to the safety distances S1, S2 along the sinusoidal trajectory 20 in the Fig. 2. The dashed arrows show the vehicle lengths F1, F2 and the safety distances S1, S2 during the controlled sinusoidal trajectory 20. In the Fig. 2, the safety distances S1, S2 between the vehicles 11, 12, 13 can be set particularly small to maximize energy savings. Alternatively, the wavelength T can also be formed by the vehicle lengths F1, F2 and the safety distances S1, S2 along the longitudinal direction X in order to increase the actual distances between the vehicles 11, 12, 13 when cornering along the sinusoidal trajectory 20.

[0042] The vertical lines V illustrate a difference in the safety distances S1, S2 between regular straight-ahead travel and cornering (dashed arrows) along the sinusoidal trajectory 20. A lane width B of a lane 30 traveled by the vehicle convoy 10 can be measured by at least one sensor (not shown) and / or received from a database. Preferably, the sinusoidal trajectory 20 is adjusted by at least one control unit 21 of the first vehicle 11 such that, at local maxima or minima of the sinusoidal trajectory 20, the vehicles 11, 12, 13 are steered to an edge 31, 32 of the lane 30. At local maxima or minima of the sinusoidal trajectory 20, the vehicles are steered such that they do not travel laterally beyond the lane boundary or a lane edge 31, 32. LIST OF REFERENCE SYMBOLS: 10 vehicle convoy 11 first vehicle / lead vehicle 12 second vehicle 13 third vehicle 20 sinusoidal trajectory 21 Control unit of the first vehicle 22 Control unit of the second vehicle 23 Control unit of the third vehicle 30 lanes 31 left lane edge 32 right lane edge B Lane width F1 first car length F2 second vehicle length S1 second safety distance S2 first safety distance T wavelength of the sinusoidal trajectory X Longitudinal direction Y transverse direction along the lane width

Claims

[1] Method for operating a vehicle convoy (10) with at least three vehicles (11, 12, 13), wherein a first safety distance (S1) from the first vehicle (11) is set by a second vehicle (12) and a second safety distance (S2) from the second vehicle (12) is set by at least one third vehicle (13) immediately following the second vehicle (12), and / or a second safety distance (S2) is set between at least two third vehicles (13) following the second vehicle (12), wherein communication links are set up between control units (21, 22, 23) for the longitudinal guidance and / or transverse guidance of the vehicles (11, 12, 13) in order to adapt the longitudinal guidance and / or transverse guidance of the second vehicle (12) and of the at least one third vehicle (13) to the first vehicle (11), wherein when a braking operation of the vehicle convoy (10) is initiated, the vehicles (11, 12,13) into a sinusoidal trajectory (20). [2] Method according to claim 1, wherein the first safety distance (S1) is set greater than the second safety distance (S2). [3] Method according to claim 1 or 2, wherein the braking process is initiated by the first vehicle (11) and transmitted via the communication links to the second vehicle (12) and the at least one third vehicle (13). [4] Method according to one of claims 1 to 3, wherein the first safety distance (S1) is set between 1 and 20 meters by the second vehicle (12) and / or by the first vehicle (11), wherein the first safety distance (S1) has a safety buffer to compensate for transmission delays of the communication links. [5] Method according to one of claims 1 to 4, wherein, when a braking operation is initiated, a sinusoidal trajectory (20) of the vehicles (11, 12, 13) of the vehicle convoy (10) is adjusted, which has a wavelength (T) of two vehicle lengths (F1, F2) and two safety distances (S1, S2) or which forms a wavelength by two vehicle lengths (F1, F2) and safety distances (S1, S2) angled by cornering along the sinusoidal trajectory (20). [6] Method according to one of claims 1 to 5, wherein, in addition to the regulated safety distance (S1, S2), an angular offset between the vehicles (11, 12, 13) of the vehicle convoy (10) is used when a braking operation is initiated in order to extend a possible braking distance. [7] Method according to one of claims 1 to 6, wherein the control units (22, 23) of the second vehicle (12) and of the at least one third vehicle (13) transmit vehicle lengths (F1, F2) and / or vehicle masses to the control unit (21) of the first vehicle (11) in order to adapt at least one parameter of the sinusoidal trajectory (20). [8] Method according to one of claims 1 to 7, wherein a lane width (B) of a lane (30) traveled by the vehicle convoy (10) is measured by at least one sensor and / or received from a database, wherein the sinusoidal trajectory (20) is adjusted such that at local maxima or minima of the sinusoidal trajectory (20) the vehicles (11, 12, 13) are steered to an edge (31, 32) of the lane (30). [9] Vehicle convoy (10) which is arranged to carry out a method according to one of the preceding claims.

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