A multi-train cooperative cruise control method and system considering communication distance

Abstract

The present invention discloses a multi-train cooperative cruise control method and system that takes communication distance into consideration. The method includes: obtaining the operating information of each train within the communication range in real time, calculating the distance and speed difference between each train and its communicating adjacent trains, and obtaining the maximum communication distance of the train; using the negative gradient of the potential function between the train and the communicating adjacent train to obtain the distance control variable of each train; wherein the potential function is a piecewise potential function that introduces the maximum communication distance and / or a communication coefficient that represents the communication quality between trains is introduced into the distance control variable, and the communication coefficient is a piecewise coefficient that introduces the maximum communication distance; and applying the distance control variable to the traction and braking system of the train to generate traction or braking force. The technical solution of the present invention fully considers the influence of communication distance, and uses a brand-new technical solution to optimize the train tracking interval according to the actual speed of the train while ensuring the safe operation of the train, so as to improve the overall operational efficiency of the railway.

Description

Technical Field

[0001] The present invention belongs to the technical field of train operation control, and in particular relates to a multi-train cooperative cruise control method and system taking into account communication distance. Background Art

[0002] Multi-train coordinated control methods based on artificial potential functions can improve train cruise performance and have achieved significant research results. For example, application number 2022104273125 describes a multi-train coordinated cruise control method and system based on potential functions. This method employs artificial potential functions to control the distance between high-speed trains within a safe range, dynamically adjusting the distance between trains based on their real-time operating status.

[0003] However, the potential functions proposed in most studies lack flexibility, fail to consider communication range, and cannot accurately determine potential communication interruptions and emergency braking trends between trains. Consequently, when communication anomalies occur, system control is performed as if no communication connection were present, which can easily lead to accidents. Furthermore, due to the limited power of wireless transmission, communication distance is restricted, and the communication topology between trains must be dynamically adjusted as the tracking distance changes. Therefore, it is necessary to incorporate communication distance into multi-train cooperative cruise control systems. Summary of the Invention

[0004] The purpose of the present invention is to incorporate communication distance into a multi-train cooperative cruise control system, providing a new way to define potential functions and / or control variables, thereby fully considering the impact of communication distance, and further providing a multi-train cooperative cruise control method and system that takes communication distance into account. The method proposes an adaptive piecewise potential function that takes into account the communication range, which can fully utilize the distance and speed between trains to adjust the magnitude of the potential field force in real time, thereby reducing the adverse effects of speed and communication changes on multi-train cooperative control. An adjustable communication coefficient that describes the change in communication topology weight is designed. While ensuring the safe operation of the train, the train tracking interval is optimized according to the actual train speed to improve the overall operational efficiency of the railway.

[0005] To this end, the present invention provides the following technical solutions:

[0006] On the one hand, the present invention provides a multi-train cooperative cruise control method considering communication distance, comprising the following steps:

[0007] Step 1: Acquire the running information of each train within the communication range in real time, wherein the real-time running information includes speed information and position information;

[0008] Step 2: Calculate the distance and speed difference between each train and its adjacent trains, and obtain the maximum communication distance between the trains;

[0009] Step 3: Use the artificial potential field to characterize the deviation between the actual tracking distance of the train and the expected safety distance, and then use the negative gradient of the potential function between the train and the communicating adjacent train to obtain the distance control variable of each train;

[0010] The potential function is a piecewise potential function that introduces the maximum communication distance and / or the piecewise coefficient that introduces the maximum communication distance is set in the distance control variable as a communication coefficient representing the communication quality between trains;

[0011] Step 4: Applying the distance control variable to the traction and braking system of the train to generate traction or braking force.

[0012] Preferably, the piecewise potential function is a piecewise asymmetric artificial potential function based on the maximum communication range, the minimum braking distance and the expected safety distance, specifically as follows:

[0013]

[0014] Where, is the potential function between train i and train j, x ij is the distance deviation between train i and train j, d r is the expected safety distance, r max is the maximum communication distance centered on the train itself, r min is the minimum braking distance of the train itself; the above potential function is an asymmetric artificial potential function that takes into account the communication distance and the minimum braking distance, v i 、v j is the actual speed of train i and train j, || || is the absolute value symbol, and e is the natural base.

[0015] Preferably, in the communication enhancement area, the closer the distance between the trains, the larger the communication coefficient, and when the distance between the trains approaches 0, the communication coefficient approaches infinity; in the communication attenuation area, the farther the distance between the trains, the smaller the communication coefficient, and when the distance between the trains approaches the maximum communication range, the communication coefficient approaches 0.

[0016] Preferably, the function of the communication coefficient is expressed as:

[0017]

[0018] Where, the communication coefficient a ij It represents the communication quality between train i and train j, which is related to the actual communication distance, which is the actual distance x between the two trains. ij; A is the adjacency matrix coefficient when the tracking distance curve converges to the expected distance (A can be determined according to environmental factors. If the communication environment is good, A is set larger; if the environment is bad, A is set smaller. The specific value is not limited in this invention and is set or adjusted according to actual needs and the environment). ω>0 and η>0 are both adjustment parameters; d r is the expected safety distance, r max is the maximum communication distance centered on the train itself, x ij is the distance deviation between train i and train j, and ‖ ‖ is the absolute value sign.

[0019] Preferably, the relationship between the communication coefficient and the distance control variable is expressed as follows:

[0020]

[0021] Where u i1 is the negative feedback of train i, i.e., the distance control variable; n is the total number of trains in the multi-train system, x i represents the position of train i, is the gradient symbol; communication coefficient a ij Indicates the communication quality between train i and train j, which is related to the actual communication distance. is the potential function between train i and train j, x ij is the distance deviation between train i and train j.

[0022] Preferably, the method further includes a speed control variable based on the speed deviation between trains, which is used to control the train speed to track the desired speed, and is expressed as:

[0023]

[0024] Among them, u i1 is the speed control variable of train i based on the speed deviation, m i is the mass of train i, v i 、v j is the actual speed of train i and train j, v r is the expected speed of train i, α>0 is a positive coefficient, n is the total number of trains in the multi-train system; the communication coefficient a ij It represents the communication quality between train i and train j, which is related to the actual communication distance.

[0025] Preferably, the method is applied to a single train or multiple train cooperative control system of a multiple train cooperative control system.

[0026] In a second aspect, the present invention further provides a control system based on the above method, which is applied to a multi-train system and comprises at least: an operation information collection subsystem, a train communication subsystem, and a control subsystem;

[0027] The operation information collection subsystem is composed of onboard equipment and / or trackside equipment of each train and is used to collect real-time operation information of each train;

[0028] The train communication subsystem is composed of the communication modules of each train and / or the radio block center, and is used to establish communication connections between trains and realize information transmission between adjacent trains;

[0029] The control subsystem is composed of controllers of each train, which is used to obtain or acquire the control variables of each train according to steps 2 to 4, and act on the traction and braking system of the train to generate traction or braking force, thereby controlling the acceleration change of the train.

[0030] In a third aspect, the present invention further provides an electronic terminal comprising: one or more processors; and a memory storing one or more computer programs;

[0031] Among them, the processor calls the computer program to implement: a multi-train cooperative cruise control method considering communication distance.

[0032] In a fourth aspect, the present invention also provides a readable storage medium storing a computer program, which is called by a processor to implement: steps of a multi-train cooperative cruise control method considering communication distance.

[0033] Beneficial effects

[0034] 1. The present invention provides a multi-train cooperative cruise control method that takes communication distance into consideration. It is the first time to propose incorporating the communication distance factor into the multi-train cooperative cruise control system. It fully considers that if the communication range is not taken into consideration, communication interruption and emergency braking trends will have an impact on the cooperative control system, and the communication topology between trains should also be dynamically adjusted as the tracking distance changes, thereby providing a new technical idea / means to achieve multi-train cooperative cruise control. Among them, on the one hand, an adaptive piecewise potential function that takes the communication range into consideration is proposed, and the speed difference between the two trains is also considered at the same time. Even if the distance is consistent, the potential field force will exist when the speed is inconsistent. It can make full use of the distance and speed between the trains to adjust the size of the potential field force in real time, thereby reducing the adverse effects of speed changes and communication changes on multi-train cooperative control. On the other hand, an adjustable communication coefficient that describes the change of the communication topology weight is proposed, that is, it is dynamically adjusted according to the actual distance, which is more in line with the application situation and further ensures smooth and orderly control between trains.

[0035] 2. The present invention uses an artificial potential field to characterize the deviation between a train's actual tracking distance and its desired safe distance. An asymmetric potential function is constructed based on the communication distance and minimum braking distance. When a train's actual tracking distance exceeds the desired safe distance but is within the communication range, the artificial potential field based on the potential function generates an attractive force, causing the following train to accelerate, thereby reducing the distance between them. When the train's actual tracking distance falls below the desired safe distance, the artificial potential field based on the potential function generates a strong repulsive force, causing the following train to rapidly decelerate, thereby increasing the distance between them. The closer the train approaches the minimum braking distance, the greater the repulsive force, thus preventing the train from exceeding the minimum braking distance. Therefore, the strategy proposed by the present invention can effectively reduce violations of the minimum braking distance by limiting the range of train coordination, while ensuring train safety and converging to the desired safe distance. Furthermore, the potential field exists only within the communication range, not throughout the entire space.

[0036] 3. In the preferred embodiment of the present invention, the communication coefficient is optimized and set to an adaptive coefficient a according to the actual distance change. ij , the communication matrix can be automatically adjusted in real time according to the actual operating conditions to better meet the needs of actual applications. At the same time, performance indicators (such as comfort, energy saving, convergence speed, etc.) can be optimized by appropriately selecting the adjustment parameters ω and η. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0038] Figure 1 This is a flow chart of a multi-high-speed train cooperative cruise control method based on a communication distance potential function provided by the present invention;

[0039] Figure 2 This is a schematic diagram of the cooperative control principle based on the communication distance potential function of the present invention;

[0040] Figure 3 It is a schematic diagram of the communication coefficient. DETAILED DESCRIPTION

[0041] The present invention provides a multi-train cooperative cruise control method that takes into account the communication distance, which is applied to a single train or multi-train cooperative control system of a multi-train cooperative control system. Its core optimization lies in the introduction of the communication range, that is, the communication factor of the train is taken into account. Among them, the preferred potential function is a piecewise potential function that introduces the maximum communication distance, and / or a piecewise coefficient that introduces the maximum communication distance is set in the distance control variable as a communication coefficient that represents the communication quality between trains. The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0042] Example 1:

[0043] An embodiment of the present invention provides a multi-train coordinated cruise control method considering communication distance, comprising the following steps:

[0044] Step 1: Acquire the running information of each train within the communication range in real time, including speed information and position information.

[0045] This embodiment illustrates the control method using a train control system as an example. This control system includes at least an operation information collection subsystem, a train communication subsystem, and a control subsystem. The operation information collection subsystem, comprised of onboard equipment and / or trackside equipment on each train, collects real-time operation information from each train. The train communication subsystem, comprised of communication modules and / or radio block centers on each train, establishes inter-train communication links and enables information transmission between adjacent trains. The control subsystem, comprised of controllers on each train, obtains or acquires control variables for each train and applies them to the train's traction and braking systems to generate traction or braking force, thereby controlling changes in train acceleration.

[0046] Step 2: Calculate the distance and speed difference between each train and its adjacent trains, and obtain the maximum communication distance of the trains.

[0047] Step 3: Use the artificial potential field to characterize the deviation between the actual tracking distance of the train and the expected safety distance, and then use the negative gradient of the potential function between the train and the communicating adjacent train to obtain the distance control variable of each train.

[0048] In the embodiment, the piecewise potential function is preferably a piecewise function based on the maximum communication range, the minimum braking distance and the expected safety distance, as follows:

[0049]

[0050] Where, is the potential function between train i and train j, x ij is the distance deviation between train i and train j, d r is the expected safety distance, r max is the maximum communication distance centered on the train itself, r min is the minimum braking distance of the train itself. The above potential function is an asymmetric artificial potential function that takes into account the communication distance and the minimum braking distance. i 、v j is the actual speed of train i and train j, || || is the distance symbol or difference symbol, and e is the natural base.

[0051] Based on the above potential function, the distance control variable is expressed as follows:

[0052]

[0053] Among them, u i1 is the negative feedback of train i, i.e., the distance control variable; n is the total number of trains in the multi-train system, x i represents the position of train i, is the gradient symbol, the communication coefficient a ij It represents the communication quality between train i and train j, which is related to the actual communication distance.

[0054] In this embodiment, the preferred communication coefficient a ij The function is expressed as:

[0055]

[0056] Where, the communication coefficient a ij represents the communication quality between train i and train j, which is related to the actual communication distance; A is the adjacency matrix coefficient when the tracking distance curve converges to the expected distance, ω>0 and η>0 are both adjustment parameters; d r is the expected safety distance, r max is the maximum communication distance centered on the train itself, x ij is the distance deviation between train i and train j.

[0057] like Figure 3 As shown, different parameters are selected to draw the curve of the function. It can be seen from the figure that a ij The changes have the following characteristics:

[0058] 1. When the distance between any two adjacent trains in the fleet is distributed in the communication enhancement area, the closer the distance, the larger the value. j (t)-x i (t)||→0, there exists a ij→+∞,i,j∈[1,n].

[0059] 2. When the distance between train i and train j converges to the expected distance dr, a ij →A.

[0060] 3. When the distance between any two adjacent trains in the fleet is distributed in the communication attenuation area, the farther the distance, the smaller the value. j (t)-x i (t)||→r max When there is a ij →0.

[0061] It should be noted that, in this embodiment, both the potential function and the above-mentioned communication coefficient are optimized, and the communication coefficient is incorporated into the control equation; in other feasible embodiments, choosing to optimize one of the potential function or the communication coefficient can also be regarded as meeting the technical requirements of the present invention, but the effect is not as good as the preferred solution of this embodiment, such as selecting the potential function of the prior art 2022104273125, a multi-train cooperative cruise control method and system based on potential function, but selecting the communication coefficient of this embodiment for optimization.

[0062] It should be understood that the control variable in this embodiment is the control input, that is, the magnitude of the train's acceleration, which informs the traction and braking system of the magnitude of the acceleration to generate a corresponding magnitude of traction or braking force. In addition, this embodiment only constrains the train's distance control variable to be considered in the control variable, and does not constrain other components of the control variable. Therefore, the constructed control variable can be set based on other requirements of the train system control. In this embodiment, u i2 As part of the control variables, the following are included:

[0063]

[0064] Among them, u i2 is the speed control variable of train i based on the speed deviation, m i is the mass of train i, v i 、v j is the actual speed of train i and train j, v r is the expected speed of train i, α>0 is a positive coefficient, and n is the total number of trains in the multi-train system.

[0065] Step 4: Apply the distance control variable to the train's traction and braking system to generate traction or braking force. Therefore, repeat steps 1 through 4 until all trains are operating at a common desired speed and maintaining a stable safe distance from adjacent trains. It should be understood that in other feasible embodiments, if additional control variables are present, these various control variables are weighted to determine the final control variable, which is then applied to the train's traction and braking system to generate traction or braking force.

[0066] It should be noted that the above control method can also be applied to a single train in a multi-train system, that is, the single train receives instructions from the control subsystem for control or receives information from other adjacent trains, and generates control variables according to the above method to achieve braking control.

[0067] Example 2:

[0068] An embodiment of the present invention provides an electronic terminal, comprising: one or more processors; and a memory storing one or more computer programs;

[0069] The processor calls the computer program to implement: a multi-train cooperative cruise control method considering communication distance. Specifically, the method:

[0070] Step 1: Acquire the running information of each train within the communication range in real time, wherein the real-time running information includes speed information and position information.

[0071] Step 2: Calculate the distance and speed difference between each train and its adjacent trains, and obtain the maximum communication distance of the trains.

[0072] Step 3: Use the artificial potential field to characterize the deviation between the actual tracking distance of the train and the expected safety distance, and then use the negative gradient of the potential function between the train and the communicating adjacent train to obtain the distance control variable of each train.

[0073] Step 4: Applying the distance control variable to the traction and braking system of the train to generate traction or braking force.

[0074] For the specific implementation process of each step, please refer to the description of the above method.

[0075] It should be understood that in the embodiments of the present invention, the processor referred to may be a central processing unit (CPU), and the processor may also be other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or the processor may also be any conventional processor, etc. The memory may include a read-only memory and a random access memory, and provides instructions and data to the processor. A portion of the memory may also include a non-volatile random access memory. For example, the memory may also store information about the device type.

[0076] Example 3:

[0077] An embodiment of the present invention provides a readable storage medium storing a computer program, wherein the computer program is called by a processor to implement: steps of a multi-train cooperative cruise control method considering communication distance.

[0078] Specific implementation:

[0079] Step 1: Acquire the running information of each train within the communication range in real time, wherein the real-time running information includes speed information and position information.

[0080] Step 2: Calculate the distance and speed difference between each train and its adjacent trains, and obtain the maximum communication distance of the trains.

[0081] Step 3: Use the artificial potential field to characterize the deviation between the actual tracking distance of the train and the expected safety distance, and then use the negative gradient of the potential function between the train and the communicating adjacent train to obtain the distance control variable of each train.

[0082] Step 4: Applying the distance control variable to the traction and braking system of the train to generate traction or braking force.

[0083] For the specific implementation process of each step, please refer to the description of the above method.

[0084] The readable storage medium is a computer-readable storage medium, which can be an internal storage unit of the software and hardware device described in any of the aforementioned embodiments, such as a hard disk or memory of a controller. The readable storage medium can also be an external storage device of the controller, such as a plug-in hard disk equipped on the controller, a smart memory card (Smart Media Card, SMC), a secure digital (Secure Digital, SD) card, a flash card (Flash Card), etc. Furthermore, the readable storage medium can also include both an internal storage unit of the controller and an external storage device. The readable storage medium is used to store the computer program and other programs and data required by the controller. The readable storage medium can also be used to temporarily store data that has been output or is to be output.

[0085] Based on this understanding, the technical solution of the present invention, or the portion that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes instructions for causing a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present invention. The aforementioned readable storage medium includes various media that can store program code, such as a USB flash drive, a mobile hard disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0086] Those skilled in the art will appreciate that the embodiments of the present application can be provided as methods, systems, or computer program products. Therefore, the present application can adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present application can adopt the form of a computer program product implemented on one or more computer-readable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code. The present application is a flow chart according to the method, device (system), and computer program product of the embodiment of the present application and / or the instructions executed by the processor to generate a device for realizing the function specified in one flow chart or multiple flows and / or one box or multiple boxes of the block diagram. These computer program instructions can also be stored in a computer-readable memory that can guide a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer-readable memory generate a product comprising an instruction device, which realizes the function specified in one flow chart or multiple flows and / or one box or multiple boxes of the block diagram. These computer program instructions may also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, whereby the instructions executed on the computer or other programmable device provide steps for implementing the functions specified in one or more processes in the flowchart and / or one or more boxes in the block diagram.

[0087] It should be emphasized that the examples described in the present invention are illustrative rather than restrictive. Therefore, the present invention is not limited to the examples described in the specific embodiments. Any other embodiments derived by those skilled in the art based on the technical solution of the present invention that do not depart from the purpose and scope of the present invention, whether modified or replaced, also fall within the scope of protection of the present invention.

Claims

1. A multi-train coordinated cruise control method considering communication distance, characterized by: The following steps are involved: Step 1: Acquire the running information of each train within the communication range in real time, wherein the real-time running information includes speed information and position information; Step 2: Calculate the distance and speed difference between each train and its adjacent trains, and obtain the maximum communication distance between the trains; Step 3: Use the artificial potential field to characterize the deviation between the actual tracking distance of the train and the expected safety distance, and then use the negative gradient of the potential function between the train and the communicating adjacent train to obtain the distance control variable of each train; The potential function is a piecewise potential function that introduces the maximum communication distance and / or the distance control variable is provided with a piecewise coefficient that introduces the maximum communication distance as a communication coefficient representing the communication quality between trains; Step 4: Applying the distance control variable to the traction and braking system of the train to generate traction or braking force.

2. The method according to claim 1, wherein: The piecewise potential function is a piecewise asymmetric artificial potential function based on the maximum communication range, the minimum braking distance and the expected safety distance, as follows: Where, is the potential function between train i and train j, x ij is the distance deviation between train i and train j, d r is the expected safety distance, r max is the maximum communication distance centered on the train itself, r min is the minimum braking distance of the train itself; v i 、v j is the actual speed of train i and train j, || || is the absolute value symbol, and e is the natural base.

3. The method according to claim 1, wherein: In the communication enhancement area, the closer the distance between trains, the larger the communication coefficient is. When the distance between trains approaches 0, the communication coefficient approaches infinity. In the communication attenuation area, the farther the distance between trains, the smaller the communication coefficient is. When the distance between trains approaches the maximum communication range, the communication coefficient approaches 0.

4. The method according to claim 1, wherein: The function of the communication coefficient is expressed as: Where, the communication coefficient a ij represents the communication quality between train i and train j, which is related to the actual communication distance; A is the adjacency matrix coefficient when the tracking distance curve converges to the expected distance, ω>0 and η>0 are both adjustment parameters; d r is the expected safety distance, r max is the maximum communication distance centered on the train itself, x ij is the distance deviation between train i and train j, and || || is the absolute value sign.

5. The method according to any one of claims 3 or 4, characterized in that: The relationship between the communication coefficient and the distance control variable is expressed as follows: Among them, u i1 is the negative feedback of train i, i.e., the distance control variable; n is the total number of trains in the multi-train system, x i represents the position of train i, is the gradient symbol; communication coefficient a ij Indicates the communication quality between train i and train j, which is related to the actual communication distance. is the potential function between train i and train j, x ij is the distance deviation between train i and train j.

6. The method according to any one of claims 3 or 4, characterized in that: There is also a speed control variable based on the speed deviation between trains, which is used to control the train speed to track the desired speed, expressed as: Among them, u i2 is the speed control variable of train i based on the speed deviation, m i is the mass of train i, v i 、v j is the actual speed of train i and train j, v r is the expected speed of train i, α>0 is a positive coefficient, n is the total number of trains in the multi-train system; the communication coefficient a ij It represents the communication quality between train i and train j, which is related to the actual communication distance.

7. The method according to claim 1, wherein: The method is applied to a single train or multiple train cooperative control system of a multiple train cooperative control system.

8. A control system based on the method according to any one of claims 1 to 7, applied to a multi-train system, characterized in that: At least: Operation information collection subsystem, train communication subsystem and control subsystem; The operation information collection subsystem is composed of onboard equipment and / or trackside equipment of each train and is used to collect real-time operation information of each train; The train communication subsystem is composed of the communication modules of each train and / or the radio block center, and is used to establish communication connections between trains and realize information transmission between adjacent trains; The control subsystem is composed of controllers of each train, which is used to obtain or acquire the control variables of each train according to steps 2 to 4, and act on the traction and braking system of the train to generate traction or braking force, thereby controlling the acceleration change of the train.

9. An electronic terminal, characterized in that: include: one or more processors; a memory storing one or more computer programs; The processor calls the computer program to implement: The steps of the multi-train cooperative cruise control method according to any one of claims 1 to 7.

10. A readable storage medium, characterized in that: A computer program is stored, which is called by a processor to implement: The steps of the multi-train cooperative cruise control method according to any one of claims 1 to 7.

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