Differential torque control method and device for electric vehicle, terminal and storage medium

Abstract

The invention discloses an electric automobile differential torque control method and device, a terminal and a storage medium in the technical field of electric automobile distributed driving, and aims to solve the problems that in the prior art, when the rotating speeds of inner and outer wheels during steering of an automobile are controlled, slip control over the wheels is generally lacked, so that the controllability of the whole automobile is poor, and the stability of the automobile is poor. The overall torque imbalance is easily caused, and the stability of the vehicle during steering is influenced. The method comprises the following steps: acquiring a torque distribution coefficient under a preset working condition; calculating a torque correction scale factor; calculating an inner side wheel torque and an outer side wheel torque; torque is distributed proportionally with equal slip rate as a control target, and slip control of wheels and controllability of the whole vehicle are ensured while the rotation speed difference of inner and outer wheels during steering is realized by utilizing the characteristic of independent control of the torque of the two wheels, so that electronic differential control of the distributed driving electric vehicle is realized, overall torque imbalance is avoided, and the stability of the vehicle is improved. And the steering stability of the vehicle is ensured.

Description

Technical Field

[0001] The invention relates to a method, a device, a terminal and a storage medium for controlling differential torque of an electric vehicle, and belongs to the technical field of distributed drive of electric vehicles. Background Art

[0002] The traditional "oil-to-electric" central transmission electric vehicle has more transmission system components, more mechanical losses, and higher energy consumption of the whole vehicle; the layout space of the whole vehicle is relatively tight, and it is impossible to arrange more power batteries, and the vehicle's cruising range is short. Since the power batteries are mostly rear-mounted, the center of gravity of the whole vehicle is high and the handling stability is also poor. With the continuous maturity and application of distributed electric drive axle technology, it not only saves chassis space, but also improves transmission efficiency, improves vehicle power and stability, and solves various problems caused by the transmission layout. The commonly used speed control method is to use the Ackermann steering model to determine the target speed of each drive wheel according to the steering angle, and then use PID to achieve speed closed-loop control of each drive wheel. The torque fluctuation caused by the speed fluctuation of a single drive wheel will directly lead to the output torque fluctuation of the whole vehicle, that is, the overall torque imbalance caused by the drive wheel when the unexpected disturbance decreases.

[0003] In the prior art, when controlling the speed of the inner and outer wheels when the vehicle is turning, there is usually a lack of wheel slip control, which leads to poor controllability of the entire vehicle, easily causes overall torque imbalance, and affects the stability of the vehicle when turning. Summary of the invention

[0004] The purpose of the present invention is to overcome the deficiencies in the prior art and to provide a method, device, terminal and storage medium for differential torque control of an electric vehicle, which takes equal slip rate as the control target and calculates the torque correction proportional factor to obtain the inner wheel torque and the outer wheel torque, thereby ensuring the slip control of the wheels and the maneuverability of the entire vehicle while achieving the speed difference between the inner and outer wheels during steering.

[0005] In order to solve the above technical problems, the present invention is implemented by adopting the following technical solutions: In a first aspect, the present invention provides a method for controlling differential torque of an electric vehicle, comprising the following steps: Obtaining an inner wheel adhesion coefficient and an outer wheel adhesion coefficient, and obtaining a torque distribution coefficient under a preset working condition according to the inner wheel adhesion coefficient and the outer wheel adhesion coefficient; wherein the torque distribution coefficient under the preset working condition is represented by a vehicle speed; Obtaining the vehicle speed, the inner wheel speed, and the outer wheel speed, calculating a first estimated vehicle speed according to the vehicle speed and the inner wheel speed, and calculating a second estimated vehicle speed according to the vehicle speed and the outer wheel speed; calculating a torque correction proportional factor according to the first estimated vehicle speed and the second estimated vehicle speed; The actual torque is obtained, and the torque difference is calculated according to the torque distribution coefficient and the torque correction proportional factor. The inner wheel torque and the outer wheel torque are calculated according to the torque difference and the actual torque to complete the torque distribution.

[0006] Further, the obtaining of the inner wheel adhesion coefficient and the outer wheel adhesion coefficient specifically includes: When the vehicle is turning, the wheel on the side close to the turning center is the inner wheel, and the wheel on the other side is the outer wheel; The expression of the inner wheel adhesion coefficient is as follows: ; Where: is the inner wheel adhesion coefficient; is the adhesion of the inner wheel; is the vertical load on the inner wheel; The expression of the outer wheel adhesion coefficient is as follows: ; Where: is the adhesion coefficient of the outer wheel; is the adhesion of the outer wheel; is the vertical load on the outer wheel.

[0007] Furthermore, the obtaining of the torque distribution coefficient under the preset working condition specifically includes: Under the preset working conditions, the expressions of the inner wheel adhesion coefficient and the outer wheel adhesion coefficient are as follows: ; The expression of torque distribution coefficient is as follows: ; Where; is the torque distribution coefficient; It is obtained that the expression of the torque distribution coefficient under the preset working condition is as follows: ; Where: L is the wheelbase of the vehicle; W is the horizontal distance from the center of gravity of the vehicle to the rear axle; H is the height from the center of gravity of the vehicle to the ground; B is the wheelbase of the vehicle; is the acceleration due to gravity; is the wheel angle, which is obtained by the steering wheel sensor; v is the vehicle speed.

[0008] Further, the calculating the first estimated vehicle speed and the calculating the second estimated vehicle speed specifically include: According to the instantaneous center theorem, we know that: ; Where: R is the turning radius of the vehicle; is the linear speed of the inner wheel; is the turning radius of the inner wheel; is the outer wheel linear speed; is the turning radius of the outer wheel; Among them, the vehicle turning radius The expression is as follows: ; According to the vehicle speed and the inner wheel speed, a first estimated vehicle speed is calculated, and according to the vehicle speed and the outer wheel speed, a second estimated vehicle speed is calculated, and the expression is as follows: ; Where: is the first estimated vehicle speed; is the second estimated vehicle speed; is the inner wheel speed; is the outer wheel speed.

[0009] Furthermore, the expression for calculating the torque correction proportional factor is as follows: ; Where: is the torque correction proportional factor, is the proportionality coefficient.

[0010] Furthermore, the obtaining of the actual torque specifically includes: Get the total required power and the current accelerator pedal opening, and get the actual torque based on the total required power and the current accelerator pedal opening. The expression is as follows: ; Where: is the total required power; is the maximum power of the motor; is the current accelerator pedal opening; is the current accelerator pedal output voltage; X is the maximum accelerator pedal output voltage; is the actual torque.

[0011] Furthermore, the torque difference is calculated, and the inner wheel torque and the outer wheel torque are calculated according to the torque difference and the actual torque. The specific expression is as follows: ; Where: is the torque difference; is the inner wheel torque; is the outer wheel torque.

[0012] In a second aspect, the present invention provides an electric vehicle differential torque control device, based on the electric vehicle differential torque control method described in the first aspect, the device comprises: A first calculation module: used to obtain the inner wheel adhesion coefficient and the outer wheel adhesion coefficient, and obtain the torque distribution coefficient under a preset working condition according to the inner wheel adhesion coefficient and the outer wheel adhesion coefficient; wherein the torque distribution coefficient under the preset working condition is represented by the vehicle speed; A second calculation module: used for obtaining the vehicle speed, the inner wheel speed and the outer wheel speed, calculating a first estimated vehicle speed according to the vehicle speed and the inner wheel speed, and calculating a second estimated vehicle speed according to the vehicle speed and the outer wheel speed; A third calculation module: used for calculating a torque correction proportional factor according to the first estimated vehicle speed and the second estimated vehicle speed; Distribution module: used to obtain actual torque, calculate the torque difference according to the torque distribution coefficient and the torque correction proportional factor, calculate the inner wheel torque and the outer wheel torque according to the torque difference and the actual torque, and complete torque distribution.

[0013] In a third aspect, the present invention provides a terminal, including a processor and a storage medium; The storage medium is used to store instructions; The processor is used to operate according to the instructions to execute the steps of the method according to the first aspect.

[0014] In a fourth aspect, the present invention provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the method described in the first aspect.

[0015] Compared with the prior art, the present invention has the following beneficial effects: The electric vehicle differential torque control method takes equal slip rate as the control target and calculates the torque correction proportional factor to obtain the inner wheel torque and the outer wheel torque. While achieving the inner and outer wheel speed difference during steering, the wheel slip control and the maneuverability of the whole vehicle are ensured, thereby realizing electronic differential control of distributed drive electric vehicles, avoiding overall torque imbalance, and ensuring the stability of the vehicle during steering. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a flow chart of a differential torque control method for an electric vehicle provided according to an embodiment of the present invention; Figure 2 Schematic diagram of the relationship between adhesion coefficient and slip rate provided according to an embodiment of the present invention. DETAILED DESCRIPTION

[0017] The technical solution of the present invention is described in detail below through the accompanying drawings and specific embodiments. It should be understood that the embodiments of the present invention and the specific features in the embodiments are detailed descriptions of the technical solution of the present invention, rather than limitations on the technical solution of the present invention. The embodiments of the present invention and the technical features in the embodiments may be combined with each other unless there is a conflict.

[0018] Embodiment 1: like Figure 1 As shown, the present invention provides a distributed drive electric vehicle differential torque control method, comprising the following steps: Obtaining an inner wheel adhesion coefficient and an outer wheel adhesion coefficient, and obtaining a torque distribution coefficient under a preset working condition according to the inner wheel adhesion coefficient and the outer wheel adhesion coefficient; wherein the torque distribution coefficient under the preset working condition is represented by a vehicle speed; Obtaining the vehicle speed, the inner wheel speed, and the outer wheel speed, calculating a first estimated vehicle speed according to the vehicle speed and the inner wheel speed, and calculating a second estimated vehicle speed according to the vehicle speed and the outer wheel speed; calculating a torque correction proportional factor according to the first estimated vehicle speed and the second estimated vehicle speed; The actual torque is obtained, and the torque difference is calculated according to the torque distribution coefficient and the torque correction proportional factor. The inner wheel torque and the outer wheel torque are calculated according to the torque difference and the actual torque to complete the torque distribution.

[0019] In one embodiment, obtaining the inner wheel adhesion coefficient and the outer wheel adhesion coefficient specifically includes: When the vehicle is turning, the wheel on the side close to the turning center is the inner wheel, and the wheel on the other side is the outer wheel; The expression of the inner wheel adhesion coefficient is as follows: ; Where: is the inner wheel adhesion coefficient; is the adhesion of the inner wheel; is the vertical load on the inner wheel; The expression of the outer wheel adhesion coefficient is as follows: ; Where: is the adhesion coefficient of the outer wheel; is the adhesion of the outer wheel; is the vertical load on the outer wheel.

[0020] In one embodiment, obtaining the torque distribution coefficient under a preset working condition specifically includes: Under the preset working conditions, the expressions of the inner wheel adhesion coefficient and the outer wheel adhesion coefficient are as follows: ; The expression of torque distribution coefficient is as follows: ; Where; is the torque distribution coefficient; It is obtained that the expression of the torque distribution coefficient under the preset working condition is as follows: ; Where: L is the wheelbase of the vehicle; W is the horizontal distance from the center of gravity of the vehicle to the rear axle; H is the height from the center of gravity of the vehicle to the ground; B is the wheelbase of the vehicle; is the acceleration due to gravity; is the wheel angle, which is obtained by the steering wheel sensor; v is the vehicle speed.

[0021] Specifically, the adhesion coefficient , is an important indicator to characterize the steering stability of the vehicle, and its expression is as follows; ; Where: For adhesion, is the vertical load on the wheel; like Figure 2 As shown, the adhesion coefficient It is directly related to the slip rate and can be adjusted by the torque of the motor. A reasonable electronic differential control method can control the slip rate of the drive wheel within the target range. To avoid dragging or sliding when the vehicle turns; is the peak adhesion coefficient; It can be seen that under the preset working conditions, the adhesion coefficient of the inner wheel is consistent with the adhesion coefficient of the outer wheel: ; Based on this, the torque distribution is carried out, and the expression of the torque distribution coefficient is as follows: ; When the vehicle is turning, the centrifugal force causes the load on the inner wheel to decrease and the load on the outer wheel to increase, that is, the wheel load is transferred, and as the vehicle speed increases and the steering wheel angle increases, the load transfer phenomenon becomes more obvious; the motor target torque is distributed according to the load ratio of the wheels on both sides, which can maximize the driving force. At this time, the torque distribution coefficient under the preset working condition is expressed as follows: .

[0022] In one embodiment, the calculating the first estimated vehicle speed and the calculating the second estimated vehicle speed specifically include: According to the instantaneous center theorem, we know that: ; Where: R is the turning radius of the vehicle; is the linear speed of the inner wheel; is the turning radius of the inner wheel; is the outer wheel linear speed; is the turning radius of the outer wheel; Among them, the vehicle turning radius The expression is as follows: ; According to the vehicle speed and the inner wheel speed, a first estimated vehicle speed is calculated, and according to the vehicle speed and the outer wheel speed, a second estimated vehicle speed is calculated, and the expression is as follows: ; Where: is the first estimated vehicle speed; is the second estimated vehicle speed; is the inner wheel speed; is the outer wheel speed.

[0023] In one embodiment, the calculation of the torque correction proportional factor specifically includes: The torque correction proportional factor is expressed as follows: ; Where: is the torque correction proportional factor, is the proportionality coefficient.

[0024] Specifically, since the wheels are prone to slip during driving, it can be considered that the wheel with a relatively high estimated vehicle speed is slipping, and the torque of the wheel on this side can be partially transferred to the wheel on the other side, thereby correcting the slip of the wheel; The speed difference obtained by the wheel motor speeds on both sides is used as the torque correction proportional factor: ; In the formula, f is the public value; The torque proportion correction method adopts a linear adjustment mechanism. Pure P value control can retain a certain static error range and meet the control model requirements; pure proportional control is used to achieve interval adaptive slip control. Substituting into f, the expression is as follows: .

[0025] In one embodiment, the obtaining of the actual torque specifically includes: Get the total required power and the current accelerator pedal opening, and get the actual torque based on the total required power and the current accelerator pedal opening. The expression is as follows: ; Where: is the total required power; is the maximum power of the motor; is the current accelerator pedal opening; is the current accelerator pedal output voltage; X is the maximum accelerator pedal output voltage; is the actual torque.

[0026] Specifically, the output voltage range of the accelerator pedal is 0 to X volts. The voltage output signal is input into the vehicle controller, and the current accelerator pedal opening is calculated. The current total required power and actual torque can be calculated through the preset vehicle maximum power. The calculated actual torque signal is used to distribute the motor target torque through the electronic differential control strategy.

[0027] In one embodiment, the calculated torque difference is used to calculate the inner wheel torque and the outer wheel torque according to the torque difference and the actual torque. The specific expression is as follows: ; Where: is the torque difference; is the inner wheel torque; is the outer wheel torque.

[0028] The present invention utilizes the characteristic of independent control of the torque of two wheels, takes equal slip rate as the control target, and calculates the torque correction proportional factor to obtain the inner wheel torque and the outer wheel torque. While achieving the speed difference between the inner and outer wheels during steering, the wheel slip control and the maneuverability of the whole vehicle are guaranteed, thereby realizing electronic differential control of distributed drive electric vehicles, avoiding overall torque imbalance, and ensuring the stability of the vehicle during steering.

[0029] The present invention adopts an algorithm combining off-line calculation and online optimization. Compared with the sequential quadratic programming solution method, the system has low complexity and high real-time calculation efficiency. The present invention focuses on the objective function of torque change, which can better balance the problem of increased energy consumption caused by large current fluctuations at the moment of motor distribution change and the problem of reduced efficiency and poor driver's subjective experience caused by increased time for the motor to transform from a low-efficiency zone to a high-efficiency zone. The slip rate control method of the present invention distributes torque in a ratio with equal slip rate as the control target, establishes a torque relationship of the driving wheel parts, and corrects the slip of the wheel through the torque correction factor of the inner and outer wheels. The stability is relatively high, thereby improving the handling stability of the vehicle.

[0030] Embodiment 2: Based on the same inventive concept as the first embodiment, the present invention provides a distributed drive electric vehicle differential torque control device, the device comprising: A first calculation module: used to obtain the inner wheel adhesion coefficient and the outer wheel adhesion coefficient, and obtain the torque distribution coefficient under a preset working condition according to the inner wheel adhesion coefficient and the outer wheel adhesion coefficient; wherein the torque distribution coefficient under the preset working condition is represented by the vehicle speed; A second calculation module: used for obtaining the vehicle speed, the inner wheel speed and the outer wheel speed, calculating a first estimated vehicle speed according to the vehicle speed and the inner wheel speed, and calculating a second estimated vehicle speed according to the vehicle speed and the outer wheel speed; A third calculation module: used for calculating a torque correction proportional factor according to the first estimated vehicle speed and the second estimated vehicle speed; Distribution module: used to obtain actual torque, calculate the torque difference according to the torque distribution coefficient and the torque correction proportional factor, calculate the inner wheel torque and the outer wheel torque according to the torque difference and the actual torque, and complete torque distribution.

[0031] Embodiment three: An embodiment of the present invention further provides a terminal, including a processor and a storage medium; The storage medium is used to store instructions; The processor is used to operate according to the instructions to execute the steps of the method described in embodiment 1.

[0032] Embodiment 4: The embodiment of the present invention further provides a computer-readable storage medium on which a computer program is stored. When the program is executed by a processor, the steps of the method described in the first embodiment are implemented.

[0033] Since the storage medium provided in the embodiment of the present invention can execute the method provided in the first embodiment of the present invention, it has the corresponding functional modules and beneficial effects of the execution method.

[0034] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems, or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present application may adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program codes.

[0035] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0036] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0037] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0038] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for controlling differential torque of an electric vehicle, characterized in that: The following steps are involved: Obtaining an inner wheel adhesion coefficient and an outer wheel adhesion coefficient, and obtaining a torque distribution coefficient under a preset working condition according to the inner wheel adhesion coefficient and the outer wheel adhesion coefficient; wherein the torque distribution coefficient under the preset working condition is represented by a vehicle speed; Obtaining the vehicle speed, the inner wheel speed, and the outer wheel speed, calculating a first estimated vehicle speed according to the vehicle speed and the inner wheel speed, and calculating a second estimated vehicle speed according to the vehicle speed and the outer wheel speed; calculating a torque correction proportional factor according to the first estimated vehicle speed and the second estimated vehicle speed; The actual torque is obtained, and the torque difference is calculated according to the torque distribution coefficient and the torque correction proportional factor. The inner wheel torque and the outer wheel torque are calculated according to the torque difference and the actual torque to complete the torque distribution.

2. The electric vehicle differential torque control method according to claim 1, characterized in that: The obtaining of the inner wheel adhesion coefficient and the outer wheel adhesion coefficient specifically includes: When the vehicle is turning, the wheel on the side close to the turning center is the inner wheel, and the wheel on the other side is the outer wheel; The expression of the inner wheel adhesion coefficient is as follows: Where: is the inner wheel adhesion coefficient; is the adhesion of the inner wheel; is the vertical load on the inner wheel; The expression of the outer wheel adhesion coefficient is as follows: Where: is the adhesion coefficient of the outer wheel; is the adhesion of the outer wheel; is the vertical load on the outer wheel.

3. The electric vehicle differential torque control method according to claim 2, characterized in that: The obtaining of the torque distribution coefficient under the preset working condition specifically includes: Under the preset working conditions, the expressions of the inner wheel adhesion coefficient and the outer wheel adhesion coefficient are as follows: The expression of torque distribution coefficient is as follows: Where; is the torque distribution coefficient; It is obtained that the expression of the torque distribution coefficient under the preset working condition is as follows: Where: L is the wheelbase of the vehicle; W is the horizontal distance from the center of gravity of the vehicle to the rear axle; H is the height from the center of gravity of the vehicle to the ground; B is the wheelbase of the vehicle; is the acceleration due to gravity; is the wheel angle, which is obtained by the steering wheel sensor; v is the vehicle speed.

4. The electric vehicle differential torque control method according to claim 3, characterized in that: The calculating the first estimated vehicle speed and the calculating the second estimated vehicle speed specifically include: According to the instantaneous center theorem, we know that: Where: R is the turning radius of the vehicle; is the linear speed of the inner wheel; is the turning radius of the inner wheel; is the outer wheel linear speed; is the turning radius of the outer wheel; Among them, the vehicle turning radius The expression is as follows: According to the vehicle speed and the inner wheel speed, a first estimated vehicle speed is calculated, and according to the vehicle speed and the outer wheel speed, a second estimated vehicle speed is calculated, and the expression is as follows: Where: is the first estimated vehicle speed; is the second estimated vehicle speed; is the inner wheel speed; is the outer wheel speed.

5. The electric vehicle differential torque control method according to claim 4, characterized in that: The expression for calculating the torque correction proportional factor is as follows: Where: is the torque correction proportional factor, is the proportionality coefficient.

6. The electric vehicle differential torque control method according to claim 5, characterized in that: The obtaining of the actual torque specifically includes: Get the total required power and the current accelerator pedal opening, and get the actual torque based on the total required power and the current accelerator pedal opening. The expression is as follows: Where: is the total required power; is the maximum power of the motor; is the current accelerator pedal opening; is the current accelerator pedal output voltage; X is the maximum accelerator pedal output voltage; is the actual torque.

7. The electric vehicle differential torque control method according to claim 6, characterized in that: The torque difference is calculated, and the inner wheel torque and the outer wheel torque are calculated according to the torque difference and the actual torque. The specific expression is as follows: Where: is the torque difference; is the inner wheel torque; is the outer wheel torque.

8. An electric vehicle differential torque control device, based on the electric vehicle differential torque control method according to any one of claims 1 to 7, characterized in that: The device comprises: A first calculation module: used to obtain the inner wheel adhesion coefficient and the outer wheel adhesion coefficient, and obtain the torque distribution coefficient under a preset working condition according to the inner wheel adhesion coefficient and the outer wheel adhesion coefficient; wherein the torque distribution coefficient under the preset working condition is represented by the vehicle speed; A second calculation module: used for obtaining the vehicle speed, the inner wheel speed and the outer wheel speed, calculating a first estimated vehicle speed according to the vehicle speed and the inner wheel speed, and calculating a second estimated vehicle speed according to the vehicle speed and the outer wheel speed; A third calculation module: used for calculating a torque correction proportional factor according to the first estimated vehicle speed and the second estimated vehicle speed; Distribution module: used to obtain actual torque, calculate the torque difference according to the torque distribution coefficient and the torque correction proportional factor, calculate the inner wheel torque and the outer wheel torque according to the torque difference and the actual torque, and complete torque distribution.

9. A terminal, characterized in that: including processor and storage medium; The storage medium is used to store instructions; The processor is configured to operate according to the instructions to execute the steps of the method according to any one of claims 1 to 7.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the steps of the method according to any one of claims 1 to 7 are implemented.

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