Method and system for improving braking smoothness of adaptive cruise control system intrusion condition

Abstract

The present invention relates to a method and system for improving the braking smoothness of an adaptive cruise control system in an intrusion condition. The method comprises the following steps: the method comprises the step of intruding behind a preceding vehicle and following the preceding vehicle stably to calculate the current inter-vehicle time distance. When the current inter-vehicle time distance is less than a minimum inter-vehicle time distance, the ADAS requests a torque reduction to make the engine enter a reverse towing condition. When the engine enters the reverse towing condition, the ADAS requests an ESP to control the deceleration of the entire vehicle. If the engine has a combustion torque in the torque reduction stage, the ADAS continues to request a torque reduction. When the actual combustion torque of the engine is 0, the engine enters a complete reverse towing condition. At this time, the ADAS controller gradually increases the requested deceleration according to the actual deceleration of the vehicle, so that the deceleration request changes continuously and smoothly during the entire deceleration process.

Description

Technical Field

[0001] The present invention belongs to the technical field of automobile intelligent driving, and in particular relates to a method and a system for improving the braking smoothness of an adaptive cruise system under intrusion conditions. Background Art

[0002] With the rapid development of the automotive industry, intelligent assisted driving systems have been widely used in various car models. As one of the intelligent driving assistance systems, the adaptive cruise system has also become a standard feature of all high-end or high-end models. With the widespread application of the adaptive cruise system, the challenges it faces from the complex and diverse driving environment are becoming increasingly severe.

[0003] For intelligent driving assistance systems above level L2, the main application road conditions are highways and urban expressways. Their important function is to provide longitudinal acceleration and deceleration control for the entire vehicle. Since deceleration control requires the coordinated work of engine torque reduction and ESP (electronic stability program) braking, it is necessary to continuously optimize and improve deceleration smoothness and subjective experience performance at the decision-making control layer.

[0004] From the power level, under low deceleration conditions, the engine can achieve vehicle deceleration by reducing torque and cutting off fuel. From the braking system level, ESP can accept the deceleration request of the ADAS (Advanced Driver Assistance System) controller, increase the wheel cylinder pressure through the hydraulic motor pressure, and thus achieve vehicle deceleration.

[0005] When the intrusion interval is less than the minimum following interval, ADAS needs to send a deceleration request to decelerate the vehicle. Since both the engine and ESP can provide braking force, the coordination of the two systems will have the following results:

[0006] 1) When the engine is not completely cut off from fuel and is in reverse drag, ESP intervenes in braking. Due to the uneven deceleration, the whole vehicle will jerk.

[0007] 2) When the engine is completely cut off from fuel, ESP does not intervene in time to reverse the engine, and the engine will vibrate noticeably due to uneven deceleration.

[0008] 3) When the engine just enters the reverse drag and fuel cut-off mode, ESP intervenes in braking, the deceleration changes smoothly, the deceleration of the whole vehicle is smooth, and the subjective experience is good.

[0009] Therefore, it is necessary to develop a processing strategy for optimizing the deceleration smoothness of the vehicle under intrusive working conditions. When the response capabilities of the power system and braking system are limited, continuous optimization and risk avoidance can be achieved through the decision-making control layer. Summary of the invention

[0010] In view of the above-mentioned deficiencies in the prior art, the technical problem to be solved by the present invention is to provide a method and system for improving the braking smoothness of an adaptive cruise system in an intrusion condition, so as to avoid the problem of uneven braking during the deceleration process of the adaptive cruise.

[0011] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0012] The method for improving the braking smoothness of an adaptive cruise control system under intrusion conditions is characterized by comprising the following steps:

[0013] S1: The vehicle turns on the adaptive cruise control function and invades the vehicle ahead at a speed higher than the speed of the vehicle ahead, and executes S2;

[0014] S2: The vehicle stably identifies the vehicle ahead and calculates the inter-vehicle time distance, and then executes S3;

[0015] S3: compare the current time interval between two shops with the minimum time interval between two shops. If the current time interval between two shops is less than or equal to the minimum time interval between two shops, execute S4. If the current time interval between two shops is greater than or equal to the minimum time interval between two shops, return to execute step S1 until the current time interval between two shops is less than or equal to the minimum time interval between two shops.

[0016] S4: Compare the actual combustion torque of the engine with the set minimum indicated torque. If the actual combustion torque of the engine is less than or equal to the minimum indicated torque, it indicates that the engine has entered the reverse towing condition, and execute S5; if the actual combustion torque of the engine is greater than the minimum indicated torque, the ADAS system requests to reduce the torque to make the engine enter the reverse towing condition, and returns to execute step S3 until the engine enters the reverse towing condition.

[0017] S5: ADAS continuously requests ESP to decelerate the vehicle and achieve a smooth transition between the actual deceleration and the target deceleration.

[0018] S6: End, the vehicle decelerates smoothly to a stop or controls the vehicle to decelerate to a stable following position.

[0019] To further improve the above technical solution, in step S2, the information perception unit recognizes that the preceding vehicle is within the planned path of the vehicle, thereby achieving stable recognition of the preceding vehicle; the information perception unit stably collects the speed of the vehicle and the preceding vehicle, and the longitudinal distance between the vehicle and the preceding vehicle, thereby calculating the current vehicle-to-vehicle time distance and outputting it.

[0020] Furthermore, in step S2, the recognition accuracy of the longitudinal distance of the vehicle's adaptive cruise control is 1 cm, and the error fluctuation of 1 cm for two consecutive frames is within a reasonable range, and the judgment cycle is not entered. The judgment cycle is 5 frames of CAN messages. It can be regarded as a valid output only if it is continuously greater than 10 cm in the current judgment cycle, and S3 is executed.

[0021] Furthermore, in step S5, ADAS continuously requests ESP to execute vehicle deceleration, and the actual deceleration of the vehicle when the engine enters the reverse towing condition gradually decreases toward the initial value of ESP intervention deceleration until the actual deceleration decreases to the set target deceleration.

[0022] Furthermore, the deceleration change between the actual deceleration and the initial value of ESP intervention deceleration is less than 0.2 m / s 2 After the engine enters the reverse towing condition, the ADAS system calculates the initial value of ESP intervention deceleration according to the actual deceleration when the engine enters the reverse towing condition and the deceleration change, so as to achieve a smooth transition decrease between the actual deceleration and the target deceleration.

[0023] The present invention also relates to a system for improving the braking smoothness of an adaptive cruise system under intrusion conditions, which is applied to intelligent driving systems above level L2; the system comprises:

[0024] Adaptive cruise control system: realizes intrusion into the vehicle ahead and stable following, including an information sensing unit, which collects the longitudinal distance between the vehicle and the vehicle ahead, and the real-time speed of the vehicle and the vehicle ahead;

[0025] ADAS: Determines whether the engine is in reverse mode based on the actual engine combustion torque, makes a corresponding decision and then issues a request;

[0026] ESP: Receives requests from ADAS and controls the vehicle's deceleration to achieve smooth braking.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] The method and system for improving the braking smoothness of an adaptive cruise control system in an intrusion condition of the present invention calculates the current time distance between vehicles by intruding behind a preceding vehicle and following the vehicle stably. When the current time distance between vehicles is less than a minimum time distance between vehicles, ADAS requests torque reduction to make the engine enter a reverse towing condition. When the engine enters the reverse towing condition, ADAS requests ESP to control the deceleration of the entire vehicle. If the engine has combustion torque during the torque reduction phase, ADAS continues to request torque reduction. When the actual combustion torque of the engine is 0, the engine enters a complete reverse towing condition. At this time, the ADAS control machine gradually increases the requested deceleration according to the actual deceleration of the vehicle, so that the deceleration request changes continuously and smoothly during the entire deceleration process. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 The present invention is a flow chart of a method for improving braking smoothness of an adaptive cruise control system under intrusion conditions according to an embodiment. DETAILED DESCRIPTION

[0030] The specific implementation modes of the present invention will be further described in detail below in conjunction with the accompanying drawings.

[0031] See also Figure 1 , a method for improving the braking smoothness of an adaptive cruise control system under intrusion conditions in a specific embodiment is characterized in that it specifically comprises the following steps:

[0032] S1: The vehicle turns on the adaptive cruise control function and invades the vehicle ahead at a speed higher than the speed of the vehicle ahead, and executes S2;

[0033] S2: The vehicle stably identifies the vehicle ahead and calculates the inter-vehicle time distance, and then executes S3;

[0034] S3: compare the current time interval between two vehicles with the set minimum time interval between two vehicles. If the current time interval between two vehicles is less than or equal to the minimum time interval between two vehicles, execute S4. If the current time interval between two vehicles is greater than or equal to the minimum time interval between two vehicles, return to execute step S1 until the current time interval between two vehicles is less than or equal to the minimum time interval between two vehicles.

[0035] S4: Compare the actual combustion torque of the engine with the minimum indicated torque. If the actual combustion torque of the engine is less than or equal to the minimum indicated torque, it indicates that the engine has entered the reverse towing condition, and execute S5. If the actual combustion torque of the engine is greater than the minimum indicated torque, the ADAS system continues to request a torque reduction to make the engine enter the reverse towing condition, and returns to execute step S3 until the engine enters the reverse towing condition.

[0036] S5: ADAS continuously requests ESP to decelerate the vehicle and achieve a smooth transition between the actual deceleration and the target deceleration.

[0037] S6: End, the vehicle decelerates smoothly to a stop or controls the vehicle to decelerate to a stable following position.

[0038] The method for improving the braking smoothness of the adaptive cruise control system in the intrusion condition of the embodiment is to intrude behind the front vehicle and follow the vehicle stably to calculate the current time distance between vehicles. When the current time distance between vehicles is less than the minimum time distance between vehicles, ADAS requests to reduce the torque to make the engine enter the reverse towing condition. When the engine enters the reverse towing condition, ADAS requests ESP to control the deceleration of the whole vehicle. If the engine has combustion torque in the torque reduction stage, ADAS continues to request to reduce the torque. When the actual combustion torque of the engine is 0, the engine enters the full reverse towing condition. At this time, the ADAS control machine gradually increases the requested deceleration according to the actual deceleration of the vehicle, so that the deceleration request changes continuously and smoothly during the whole deceleration process.

[0039] Please continue to see Figure 1 In step S2, the information sensing unit identifies that the preceding vehicle is within the planned path of the vehicle, thereby stably identifying the preceding vehicle; the information sensing unit stably collects the speed of the vehicle and the preceding vehicle, and the longitudinal distance between the vehicle and the preceding vehicle, thereby calculating and outputting the current vehicle-to-vehicle time distance.

[0040] In this way, through the adaptive cruise control system of this vehicle, the speed between this vehicle and the vehicle in front is collected to obtain the relative speed and the longitudinal distance between this vehicle and the vehicle in front, so the current vehicle-to-vehicle time distance = longitudinal distance / relative speed.

[0041] Among them, in step S2, the recognition accuracy of the longitudinal distance of the vehicle's adaptive cruise control is 1 cm, and the error fluctuation of 1 cm for two consecutive frames is within a reasonable range, and the judgment cycle is not entered. The judgment cycle is 5 frames of CAN messages. It can be regarded as a valid output only if it is continuously greater than 10 cm in the current judgment cycle, and S3 is executed.

[0042] During implementation, when the information perception unit recognizes that the longitudinal distance between the vehicle and the vehicle in front is continuously greater than 10 cm during the judgment period, it is used as a valid output and the current vehicle-to-vehicle time distance is calculated to enter the next control judgment logic.

[0043] Among them, in step S5, ADAS continues to request ESP to execute vehicle deceleration, and the actual deceleration of the vehicle when the engine enters the reverse towing condition gradually decreases toward the initial value of ESP intervention deceleration until the actual deceleration decreases to the set target deceleration.

[0044] The deceleration change between the actual deceleration and the initial value of ESP intervention deceleration is less than 0.2m / s 2 After the engine enters the reverse towing condition, the ADAS system calculates the initial value of ESP intervention deceleration according to the actual deceleration when the engine enters the reverse towing condition and the deceleration change, so as to achieve a smooth transition decrease between the actual deceleration and the target deceleration.

[0045] When the actual deceleration is greater than the target deceleration, the initial value of ESP intervention deceleration should be between the two, and each time ADAS requests ESP to execute vehicle deceleration, the deceleration change between the initial value sent by ESP and the current actual deceleration should be less than 0.2m / s 2 That is to say, each time ADAS requests ESP to decelerate the entire vehicle, the actual deceleration of the vehicle is different from the initial value and the value requested last time, until the actual deceleration decreases to the target deceleration, thereby achieving a smooth transition from the actual deceleration to the target deceleration.

[0046] The present invention introduces the actual combustion torque and the minimum indicated torque of the engine as a basis for judging whether the engine enters the reverse towing condition at the decision-making layer, and then ADAS requests ESP to control the deceleration of the entire vehicle to control the vehicle to decelerate smoothly to a stop or control the vehicle to decelerate to a stable following condition.

[0047] The present invention also provides a system for improving the braking smoothness of an adaptive cruise system in an intrusive working condition, which is applied to an intelligent driving system of level L2 or above; the system comprises:

[0048] Adaptive cruise control system: realizes intrusion into the vehicle ahead and stable following, including an information sensing unit, which collects the longitudinal distance between the vehicle and the vehicle ahead, and the real-time speed of the vehicle and the vehicle ahead;

[0049] ADAS: Determines whether the engine is in reverse mode based on the actual engine combustion torque, makes a corresponding decision and then issues a request;

[0050] ESP: Receives requests from ADAS and controls the vehicle's deceleration to achieve smooth braking.

[0051] In this way, the information perception unit in the adaptive cruise system serves as the input layer of the entire system in the present invention, ADAS is the decision-making layer, and ESP is the execution layer, which ultimately solves the smoothness of the actual vehicle deceleration control during the intrusion process of the ADAS controller.

[0052] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution of the present invention, which should be included in the scope of the claims of the present invention.

Claims

1. A method for improving braking smoothness of an adaptive cruise control system in an intrusion condition, characterized in that: The specific steps include: S1: The vehicle turns on the adaptive cruise control function and intrudes into the vehicle ahead at a speed higher than the speed of the vehicle ahead; S2: The vehicle stably identifies the vehicle ahead and calculates the inter-vehicle time distance, and then executes S3; S3: compare the current time interval between two different shops with the set minimum time interval between two shops. If the current time interval between two shops is less than or equal to the minimum time interval between two shops, execute S4. If the current time interval between two shops is greater than or equal to the minimum time interval between two shops, return to execute step S1. S4: Compare the actual combustion torque of the engine with the minimum indicated torque. If the actual combustion torque is ≤ the minimum indicated torque, it indicates that the engine has entered the reverse towing condition, and execute S5; if the actual combustion torque is greater than the minimum indicated torque, the ADAS system requests to reduce the actual combustion torque to make the engine enter the reverse towing condition, and returns to execute step S3 until the engine enters the reverse towing condition; S5: ADAS continuously requests ESP to decelerate the vehicle and achieve a smooth transition between the actual deceleration and the target deceleration. S6: End, the vehicle decelerates smoothly to a stop or controls the vehicle to decelerate to a stable following position.

2. The method for improving braking smoothness of an adaptive cruise control system in an intrusive condition according to claim 1, characterized in that: In step S2, the information perception unit recognizes that the preceding vehicle is within the planned path of the vehicle, and realizes stable recognition of the preceding vehicle; the information perception unit stably collects the speed of the vehicle and the preceding vehicle, and the longitudinal distance between the vehicle and the preceding vehicle, thereby calculating the current vehicle-to-vehicle time distance and outputting it.

3. The method for improving the braking smoothness of an adaptive cruise control system in an intrusive condition according to claim 2, characterized in that: In step S2, the recognition accuracy of the longitudinal distance of the vehicle's adaptive cruise control is 1 cm, and the error fluctuation of 1 cm for two consecutive frames is within a reasonable range, and the judgment cycle is not entered. The judgment cycle is 5 frames of CAN messages. It can be regarded as a valid output only if it is continuously greater than 10 cm in the current judgment cycle, and S3 is executed.

4. The method for improving braking smoothness of an adaptive cruise control system in an intrusion condition according to claim 1, characterized in that: In step S5, ADAS continuously requests ESP to execute vehicle deceleration, and the actual deceleration of the vehicle when the engine enters the reverse towing condition gradually decreases toward the initial value of ESP intervention deceleration until the actual deceleration decreases to the set target deceleration.

5. The method for improving braking smoothness of an adaptive cruise control system in an intrusion condition according to claim 4, characterized in that: The deceleration change between the actual deceleration and the initial value of ESP intervention deceleration is less than 0.2m / s 2 After the engine enters the reverse towing condition, the ADAS system calculates the initial value of ESP intervention deceleration according to the actual deceleration when the engine enters the reverse towing condition and the deceleration change, so as to achieve a smooth transition decrease between the actual deceleration and the target deceleration.

6. A system that improves the braking smoothness of the adaptive cruise control system in intrusive conditions, which is applied to intelligent driving systems above Level 2; The method for improving the braking smoothness of an adaptive cruise system under intrusion conditions as described in any one of claims 1 to 5 is characterized by comprising: Adaptive cruise control system: realizes intrusion into the vehicle ahead and stable following, including an information sensing unit, which collects the longitudinal distance between the vehicle and the vehicle ahead, and the real-time speed of the vehicle and the vehicle ahead; ADAS: Determines whether the engine is in reverse mode based on the actual engine combustion torque, makes a corresponding decision and then issues a request; ESP: Receives requests from ADAS and controls the vehicle's deceleration to achieve smooth braking.

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