Improved vehicle fleet driving
By setting safe distance in the fleet and the sine track adjustment between vehicles, the safety problem of avoiding rear-end collision during emergency braking in the fleet is solved, and the balance of energy savings is achieved.
Patent Information
- Application Number
- CN202411055822.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2023-08-03
- Filing Date
- 2024-08-02
- Publication Date
- 2025-02-14
AI Technical Summary
In a fleet, how to find a balance between ensuring safety and energy savings, especially to avoid rear-end collisions in emergency braking situations.
By setting a first safety distance between the second vehicle and the first vehicle, the second safety distance between the at least one third vehicle and the second vehicle or other third vehicle, combined with a sinusoidal trajectory between the vehicles and the angle deviation and the angle deviation between the vehicles to increase braking distance and improve traffic safety.
It realizes safe handling of the fleet in emergency braking situations, improves traffic safety, and shortens the safe distance between vehicles without affecting energy savings.
Smart Images
Figure CN119439981A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a method for operating a convoy of at least three vehicles, wherein a first safety distance from a first vehicle is set by a second vehicle and a second safety distance from the second vehicle and / or from the third vehicle is set by at least one third vehicle. In addition, the present invention also relates to a convoy. Background Art
[0002] So-called platooning or driving in a convoy is currently only carried out within the scope of experiments, but it can save additional energy. The theoretical energy savings can be in the form of fuel savings or reduced electrical energy consumption and depend not only on the frontal area or drag coefficient (Cw value) of the vehicles, but also on the distance between the vehicles in the convoy. Advantageously, the distance between the vehicles in the convoy should be as small as possible. The vehicles can be coupled to each other via a so-called electronic drag chain (Deichsel) and can therefore communicate with each other in real time to send steering and braking commands. This communication can be achieved via driver assistance systems (FAS) and car-to-car wireless communication / car-to-network communication (car2X).
[0003] The choice of distance between vehicles in a platoon constitutes a balance between safety against rear-end collisions and energy conservation. The distance between vehicles in a platoon should be set as small as possible to save energy by taking advantage of quiet wind driving / following the vehicle in front. However, emergency braking by the lead vehicle should never result in a rear-end collision with the following vehicles. Summary of the invention
[0004] It is therefore an object of the present invention to provide a method by means of which a vehicle fleet can carry out a braking maneuver with an optimized safety margin.
[0005] This object is achieved according to the invention by a method having the features of claim 1 and a vehicle fleet having the features of claim 9. Advantageous embodiments and developments are given by the dependent claims.
[0006] According to one aspect of the present invention, a method for operating a convoy of at least three vehicles is provided. In one step, a first safety distance from a first vehicle is set by a second vehicle, and a second safety distance from the second vehicle and / or from the third vehicle is set by at least one third vehicle.
[0007] Advantageously, the first vehicle may be the leading vehicle or the leader vehicle of the convoy. The second vehicle may be the vehicle following the first vehicle. In addition, at least one third vehicle may follow the second vehicle or the leading third vehicle, or be located behind it in the convoy.
[0008] In a further step, a communication link is established between control units for longitudinal control and / or transverse control of the vehicles in order to adapt the longitudinal control and / or transverse control of the second vehicle and at least one third vehicle to the first vehicle. According to the design, the control unit of the first vehicle can also execute a control command for adjusting a first safety distance to a second vehicle following behind.
[0009] In one step, the vehicles are steered into a sinusoidal trajectory when the convoy initiates a braking process.
[0010] According to another aspect of the present invention, a convoy is provided, which is configured to perform the method according to the present invention. The convoy has a first vehicle, which leads the convoy or is the leading vehicle of the convoy. A second vehicle follows the first vehicle at a first safety distance. In addition, the convoy has at least one third vehicle following the second vehicle.
[0011] A second safety distance is set between the second vehicle and a third vehicle of the at least one third vehicle that is following the second vehicle. The convoy may have a plurality of third vehicles that are located behind the second vehicle in the convoy and between which the second safety distance is set. The individual vehicles in the convoy may be identical or similar vehicles or different vehicles. In particular, the vehicles may have different sizes and masses.
[0012] By setting a sinusoidal trajectory, the vehicle is driven alternately to the edge or lane boundary within the permissible 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 distance between vehicles in a convoy or improve traffic safety by increasing the braking distance margin.
[0013] According to the design, when a sinusoidal trajectory is set, the individual vehicles of the convoy have a lateral offset and / or an angular offset with respect to each other. This measure can additionally increase the braking distance, because the individual vehicles in the convoy can brake next to the vehicle in front of it, so that a collision can be avoided by this offset. This also increases the braking distance, thereby improving traffic safety.
[0014] In one embodiment, the first safety distance is set to be greater than the second safety distance. This measure can compensate for the time delay in transmitting the braking command to the following vehicles in the convoy. If the control command of the control unit of the first vehicle is transmitted to all the following vehicles, all other safety distances can be reduced equally, because there will be no time delay in transmitting the control command between the third vehicle and between the second vehicle and the third vehicle.
[0015] In an alternative specific embodiment, if the control commands are transmitted from vehicle to vehicle, it is advantageous if the second safety distance is respectively increased or at least adjusted as a function of the first safety distance.
[0016] According to another embodiment, the braking process is initiated by the first vehicle and transmitted to the second vehicle and at least one third vehicle via the communication link.Thereby, the control unit of the first vehicle or the lead vehicle can be responsible for initiating the braking process.
[0017] According to another embodiment, the first safety distance between 1 meter and 20 meters is set by the second vehicle and / or by the first vehicle. Advantageously, the first safety distance is set so that it has a safety buffer to compensate for transmission delays of the communication link. Thus, the first safety distance can be generated by a speed-dependent distance component, which is added or multiplied with the safety buffer.
[0018] The speed-dependent distance component may be, for example, a distance calculated based on the vehicle speed and at least one parameter or vehicle parameters, such as gross mass, tire pressure, ambient temperature, weather, in order to control the vehicle to stop without colliding with a preceding vehicle in the convoy.
[0019] The safety buffer may be an absolute braking distance or a distance calculated based on the current vehicle speed and the likely or typical delay of the communication link.
[0020] Alternatively, the safety buffer can also be designed as a factor which is greater than 1 and which therefore increases the speed-dependent distance component in order to compensate for the delay of the communication link. Such a safety buffer can be determined, for example, empirically and can depend on other parameters, such as interference sources of the communication link, the load factor of the communication link, the time of day, etc.
[0021] According to another embodiment, when a braking process is initiated, a sinusoidal trajectory of the vehicles leaving the convoy is set: the wavelength of the sinusoidal trajectory is composed of two vehicle lengths and two safety distances. This measure can be used to steer a vehicle to the left edge of the lane, while the following vehicle and / or the vehicle in front is driven to the right edge of the lane. In addition to increasing the braking distance by driving in a curve, an angular offset can thus be set between the vehicles, by which the free area on the lane to the side of the vehicle in front can be used for braking in the event of emergency braking.
[0022] According to another embodiment, in the case of initiating a braking process, in addition to using the adjusted safety distance, the angular offset between the vehicles of the convoy is also used to increase the possible braking distance. Thus, the lane can be used more effectively to brake the vehicles of the convoy.
[0023] According to another embodiment, the control units of the second vehicle and at least one third vehicle transmit the vehicle length and / or vehicle mass to the control unit of the first vehicle in order to adapt at least one parameter of the sinusoidal trajectory. This enables the relevant data of the vehicles of the convoy to be gathered in the control unit of the first vehicle and enables central trajectory planning, which is provided to the accompanying vehicles of the convoy.
[0024] In this case, the sinusoidal trajectory for braking can be calculated in advance and made available to all vehicles of the convoy in order to minimize the amount of data to be transmitted when a braking maneuver is performed. Advantageously, the sinusoidal trajectory can be recalculated regularly.
[0025] Alternatively or additionally, a change in lane or road can be detected and used as a trigger signal for recalculating the sinusoidal trajectory.
[0026] According to another embodiment, the lane width of the lane in which the convoy is traveling 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 so that the vehicle is driven to the edge of the lane at a local maximum or a local minimum of the sinusoidal trajectory. Here, the vehicle is driven at a local maximum or a local minimum of the sinusoidal trajectory so that the vehicle does not go beyond the lane boundary or the lane edge in the lateral direction. BRIEF DESCRIPTION OF THE DRAWINGS
[0027] The invention is schematically illustrated by means of embodiments in the drawings and is further described with reference to the drawings, in which:
[0028] Figure 1 A schematic top view of a fleet of vehicles is shown in order to explain the method according to the invention according to an embodiment, and
[0029] Figure 2 A diagram is shown to illustrate the reduction in the distance between vehicles while maintaining the safety distance. DETAILED DESCRIPTION
[0030] In the accompanying drawings, the same reference numerals represent the same elements or structural components. The size and relative position of the elements in the accompanying drawings are not necessarily shown to scale. Here, some elements can be drawn, for example, enlarged and positioned adjusted for clarity.
[0031] Figure 1 A schematic top view of a fleet 10 according to an exemplary embodiment of the present invention is shown. The fleet 10 is configured to carry out the method according to the present invention. In particular, the method according to the present invention is explained within the scope of the description of the fleet 10.
[0032] The motorcade 10 has a first vehicle 11, which leads the motorcade 10 or is a leading vehicle of the motorcade 10. A second vehicle 12 follows the first vehicle 11 at a first safety distance S1.
[0033] Furthermore, the 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.
[0034] A second safety distance S2 is provided between the second vehicle 12 and at least one third vehicle 13. The same second safety distance S2 is also set between two third vehicles 13.
[0035] The individual vehicles 11, 12, 13 in the fleet 10 can be identical or similar vehicles or different vehicles. The vehicles 11, 12, 13 can in particular have different sizes and masses.
[0036] When setting the safety distances S1, S2, it is necessary to take into account the transit time / transmission time and delays when transmitting steering commands and braking commands for longitudinal and lateral control to the control units 21, 22, 23 of vehicles 11, 12, 13, from the sensory detection of an obstacle in the lead vehicle 11 to the processing of this information in the following vehicles 12, 13, for example in the electronic brake system (EBS) of the control unit or brake system actuator.
[0037] Since control commands are simultaneously transmitted via a communication link (not shown) between the control unit 21 of the first vehicle 11 and the control units 22 , 23 of the accompanying vehicles, the first safety distance S1 is set, for example, to be greater than the second safety distance S2 .
[0038] The safety distances S1 , S2 are defined, for example, only in the longitudinal direction X and space the individual vehicles 11 , 12 , 13 of the convoy 10 apart from one another. Figure 1 The convoy 10 is shown in the event of an initiated braking maneuver, wherein the vehicles 11, 12, 13 are adjusted onto a sinusoidal trajectory 20. The air vortices of the vehicles 11, 12, 13 are shown, for example, using the directions of travel (arrows).
[0039] By setting the sinusoidal trajectory 20, the vehicle 12 can be driven toward the left lane edge 31, and the following vehicle 13 and / or the preceding vehicle 11 can be driven toward the right lane edge 32. In addition to increasing the braking distance due to the curved driving, an angular offset can be set between the vehicles 11, 12, 13, by which the free area on the lane 30 to the side of the respective preceding vehicle 12, 11 can be used for braking in the event of emergency braking.
[0040] When the braking process is initiated, the vehicles 11, 12, 13 of the convoy 10 are set to follow a sinusoidal trajectory 20 having a wavelength T consisting of the two vehicle lengths F1, F2 arranged one behind the other and the two safety distances S1, S2 (the wavelength T corresponds to the projection of the two vehicle lengths F1, F2 arranged one behind the other and the two safety distances S1, S2 along the longitudinal direction X). Figure 2 The corresponding vehicle lengths F1, F2 and safety distances S1, S2 along the sinusoidal trajectory 20 are shown in FIG. The dashed arrows show the vehicle lengths F1, F2 and safety distances S1, S2 during the adjusted sinusoidal trajectory 20. Figure 2 In the case of the sinusoidal track 20 shown, the safety distances S1, S2 between the vehicles 11, 12, 13 can be set particularly small to maximize energy saving. Alternatively, the wavelength T can also be composed of the vehicle lengths F1, F2 in the longitudinal direction X and the safety distances S1, S2 to increase the actual distance between the vehicles 11, 12, 13 when driving along the sinusoidal track 20.
[0041] The vertical dashed line V shows the difference in safety distances S1 , S2 between normal straight driving and curved driving along the sinusoidal trajectory 20 (dashed arrows).
[0042] The lane width B of the lane 30 in which the convoy 10 is traveling 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 so that the vehicles 11, 12, 13 are driven to the edges 31, 32 of the lane 30 at the local maximum or local minimum of the sinusoidal trajectory 20. Here, the vehicles are driven at the local maximum or local minimum of the sinusoidal trajectory 20 so that the vehicles do not go out of the lane boundary or lane edge 31, 32 in the lateral direction.
[0043] List of reference numerals:
[0044] 10 Teams
[0045] 11 First vehicle / leader vehicle
[0046] 12 Second vehicle
[0047] 13 Third vehicle
[0048] 20 Sine trajectory
[0049] 21 Control unit of the first vehicle
[0050] 22 Control unit of second vehicle
[0051] 23 Control unit of third vehicle
[0052] 30 lanes
[0053] 31 Left edge of lane
[0054] Right edge of lane 32
[0055] B Lane Width
[0056] F1 First Car Length
[0057] F2 Second vehicle length
[0058] S1 First safety distance
[0059] S2 Second safety distance
[0060] T wavelength of the sinusoidal trajectory
[0061] X vertical direction
[0062] Y is the lateral direction along the lane width
Claims
1. A method for operating a convoy (10) having at least three vehicles (11, 12, 13), wherein a first safety distance (S1) is set by a second vehicle (12) from a first vehicle (11), a second safety distance (S2) is set by a third vehicle (13) of at least one third vehicle (13) that is immediately following the second vehicle (12) from the second vehicle (12), and / or a second safety distance (S2) is set between at least two third vehicles (13) that are respectively following the second vehicle (12), wherein: A communication link is established between control units (21, 22, 23) for longitudinal control and / or transverse control of vehicles (11, 12, 13) in order to adapt the longitudinal control and / or transverse control of a second vehicle (12) and at least one third vehicle (13) to the first vehicle (11), wherein the vehicles (11, 12, 13) are adjusted to a sinusoidal trajectory (20) when a braking process is initiated by the convoy (10).
2. The method according to claim 1, characterized in that The first safety distance (S1) is set to be greater than the second safety distance (S2).
3. The method according to claim 1 or 2, characterized in that: The braking process is initiated by a first vehicle (11) and transmitted to a second vehicle (12) and at least one third vehicle (13) via a communication link.
4. The method according to any one of claims 1 to 3, characterized in that A first safety distance (S1) between 1 meter and 20 meters is set 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 a transmission delay of a communication link.
5. The method according to any one of claims 1 to 4, characterized in that When a braking process is initiated, a sinusoidal trajectory (20) of the vehicles (11, 12, 13) of the convoy (10) is adjusted, the wavelength (T) of which is formed by two vehicle lengths (F1, F2) and two safety distances (S1, S2), or the wavelength of which is formed by two vehicle lengths (F1, F2) and two safety distances (S1, S2) which are angled due to curved driving along the sinusoidal trajectory (20).
6. The method according to any one of claims 1 to 5, characterized in that When a braking process is initiated, in addition to the set safety distance, the angular offset between the vehicles (11, 12, 13) of the convoy (10) is used to increase the possible braking distance.
7. The method according to any one of claims 1 to 6, characterized in that The control units (22, 23) of the second vehicle (12) and 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. The method according to any one of claims 1 to 7, characterized in that The lane width (B) of a lane (30) in which the convoy (10) is driven is measured by at least one sensor and / or received from a database, wherein the sinusoidal trajectory (20) is adjusted so that the vehicles (11, 12, 13) are driven to the edge (31, 32) of the lane (30) at a local maximum or a local minimum of the sinusoidal trajectory (20).
9. A fleet of vehicles (10) arranged to carry out the method according to any one of the preceding claims.