Determining and outputting target acceleration of a motor vehicle for automated starting of a motor vehicle with adaptive cruise control - Patents.com

Abstract

An apparatus and method are provided, each adapted to overcome the shortcomings of the prior art. A method for determining a target acceleration of a motor vehicle and outputting the determined target acceleration for automated starting of the motor vehicle by an adaptive cruise control, comprising: - increasing the target acceleration a_S from a first value to a second value; - maintaining the target acceleration a_S at a second value; and - increasing the target acceleration a_S from a second value to a target acceleration value; Do the following.

Description

[Technical field]

[0001] The present invention relates to a method for determining a target acceleration of a motor vehicle and outputting the determined target acceleration for automated starting of the motor vehicle by means of adaptive cruise control, a controller configured to carry out said method, and a motor vehicle having said controller. [Background technology]

[0002] Various similar devices and methods for automated, in particular autonomous, motor vehicle launches are known from the prior art.

[0003] That is, for example, Patent Document 1 describes a method and device for autonomously starting a motor vehicle based on a state determined by a travel sensor, where the road type of the current motor vehicle position is detected based on a navigation device or via a surrounding sensor, and on a certain road type an auto-go mode is automatically activated after prior braking to a stop, in which an autonomous starting of the vehicle is triggered by a control unit via a starting unit when the starting of another motor vehicle is determined via a starting detection unit.

[0004] Furthermore, driving assistance systems also called adaptive cruise control (distance-controlled cruise control) are known from the prior art, in which a speed control facility takes into account the distance to the preceding vehicle as a feedback and control variable in addition to the speed of the motor vehicle desired by the driver when determining the target acceleration.

[0005] Patent Documents 2 to 4 each describe the same type of adaptive cruise control.

[0006] Patent document 2 describes a method for operating a driver assistance system of a host vehicle, in particular an ACC system, in which control variables are taken into account to guide the host vehicle, target values ​​of the control variables are calculated based on relative driving dynamics measurements of the host vehicle with respect to a preceding vehicle, time gap control is performed between the host vehicle and a first preceding vehicle and type gap control is performed between the host vehicle and a second preceding vehicle, a first control variable request is derived based on the first time gap control, a second control variable request is derived based on the second time gap control, and a final control variable request is derived based on a reconciliation of the first and second control variable requests.

[0007] Patent Document 3 describes a vehicle cruise control device having a target detection unit and a following control unit. The cruise control device includes a determination unit configured to determine whether or not a small vehicle switching state occurs in which a target to be followed is a small vehicle during execution of the following control, a memory unit for an upper limit value configured to store a target acceleration as an upper limit value set before the determination of the small vehicle switching state by the determination unit under a condition in which the determination unit determines that the small vehicle switching state occurs, and a target acceleration setting unit configured to set the target acceleration to a value equal to or less than the upper limit value stored in the memory unit until the following control executed for the switched small vehicle as the target to be followed is terminated.

[0008] Patent document 4 relates to a method for selecting a target for automatic vehicle distance control of a two-wheeled motor vehicle, in which the presence of a second two-wheeled motor vehicle preceding and immediately preceding the second two-wheeled vehicle in the same driving lane is detected using surrounding sensors, the lateral deviations of the second two-wheeled motor vehicle and the third two-wheeled motor vehicle relative to the two-wheeled motor vehicle are detected, and a target for the vehicle distance control method is selected depending on at least one of the lateral deviations.

[0009] Additionally, in conventional adaptive cruise controls, separate interfaces are often provided for providing the acceleration setting or target acceleration, and for moment distribution (torque distribution) in the driving and braking directions of the motor vehicle.

[0010] The interface providing the controller used in the acceleration settings, particularly the interface, and the interface for moment distribution are unrelated to each other and there is little information exchange between the interfaces, which in conventional systems can lead to shaking and therefore an uncomfortable start when starting from a stop using adaptive cruise control. [Prior art documents] [Patent documents]

[0011] [Patent Document 1] DE 102011121442 [Patent Document 2] DE 102019214121 [Patent Document 3] US Patent Application Publication No. 2019 / 315355 [Patent Document 4] DE 102019200209 Summary of the Invention [Problem to be solved by the invention]

[0012] In the context of the prior art, it is an object of the present invention to provide an apparatus and a method, respectively, adapted to overcome at least the above-mentioned drawbacks of the prior art. [Means for solving the problem]

[0013] This problem is solved by the features of the independent claims. The dependent claims provide preferred developments of the invention.

[0014] Thereby, the object is achieved by a method for determining a target acceleration of a motor vehicle and for outputting the determined target acceleration for automated starting of the motor vehicle by means of an adaptive cruise control.

[0015] In the method, the target acceleration of the motor vehicle is controlled in an adaptive manner so as to ensure a comfortable start-off. For this purpose, the method has at least the following three steps:

[0016] The method includes a first step of increasing a target acceleration from a first value to a second value.

[0017] The method includes a second step of maintaining the target acceleration at a second value.

[0018] The method includes a third step of increasing the target acceleration from the second value to a destination acceleration value.

[0019] Ramp-up may be understood as a rise or increase in the target acceleration over time. During ramp-up, it is contemplated that the target acceleration may be increased at least partially or temporarily linearly.

[0020] During the increase of the target acceleration from the first value to the second value and during the maintenance of the target acceleration at the second value, the motor vehicle may be stopped.

[0021] Stopping may be understood here as meaning that the actual speed of the motor vehicle is essentially zero.

[0022] It is conceivable that during the maintenance of the target acceleration at the second value, an increase in the rotational speed of the internal combustion engine of the motor vehicle is carried out.

[0023] However, the method is not limited to application with internal combustion engines: it is also conceivable that starting is performed additionally or alternatively by means of an electric motor.

[0024] The motor vehicle may therefore be a motor vehicle with only an internal combustion engine (so-called pure internal combustion engine), a motor vehicle with an electric motor (so-called pure electric vehicle) or a motor vehicle with both an internal combustion engine and an electric motor (so-called hybrid).

[0025] After maintaining the target acceleration at the second value, and during the increase of the target acceleration from the second value to the destination acceleration value, the motor vehicle may launch away.

[0026] Setting off can be understood here as meaning that the actual speed of the motor vehicle is not zero. During setting off, the actual speed of the motor vehicle increases.

[0027] The rate of increase in the target acceleration during an increase in the target acceleration from the first value to the second value may be greater than the rate of increase in the target acceleration during an increase in the target acceleration from the second value to the destination acceleration value.

[0028] More precisely, the first derivative (first-order derivative) with respect to time of the target acceleration transition during the increase of the target acceleration from the first value to the second value may be greater than the first derivative (first-order derivative) with respect to time of the target acceleration during the increase of the target acceleration from the second value to the target acceleration value.

[0029] In other words, the increase may be steeper during the increase of the target acceleration from the first value to the second value than during the increase of the target acceleration from the second value to the destination acceleration value.

[0030] It is conceivable that during the increase of the target acceleration from the second value to the target acceleration value, the rate of increase of the target acceleration decreases in the course of the increase towards the target acceleration value.

[0031] More precisely, the first derivative (first-order differential) of the target acceleration with respect to time during the increase of the target acceleration from the second value to the destination acceleration value may take on smaller values ​​over time.

[0032] In other words, the increase may be more gradual over time during the rise of the target acceleration from the second value to the target acceleration value or as the target acceleration value is approached.

[0033] The above can be restated as follows:

[0034] According to the above-mentioned method, the target acceleration can be controlled in a targeted manner in order to ensure a comfortable start-off, which can be based on suitable preceding control transitions.

[0035] In the first step of the method, the target acceleration should be increased quickly from some standstill to a positive target acceleration value.

[0036] Subsequently, during a second stage of the method, the internal combustion engine can be allowed to ramp up by maintaining a minimum acceleration requirement.

[0037] After the vehicle has started, a third step of the method can involve a gradual increase in the target acceleration towards the target level, the increase being slower the closer the target acceleration is to the target level, resulting in a smooth transition to satisfaction.

[0038] The method thus makes it possible to ensure a reproducible target acceleration curve, so that a comfortable or smooth automated start-off of a motor vehicle with adaptive cruise control can be achieved.

[0039] Also provided herein is a controller configured to at least partially carry out the above-described method.

[0040] The controller may be part of a driving assistance system, in particular an adaptive cruise control. The controller may also be called a control device.

[0041] What has been said above about the method applies equally to the controller and vice versa.

[0042] Also provided herein is a motor vehicle, in particular an automobile, comprising the above-mentioned controller and a moment conversion unit connected to the controller, the moment conversion unit being configured to receive a target acceleration output from the controller, determine a target driving moment (torque) and / or a target braking moment (torque) based on the received target acceleration, and output the determined target driving moment (torque) and / or a target braking moment (torque) to the motor vehicle.

[0043] The above discussion of the method and controller applies equally to motor vehicles and vice versa.

[0044] Hereinafter, an embodiment will be described with reference to FIG. 1 and FIG. [Brief description of the drawings]

[0045] [Figure 1] FIG. 2 is a schematic diagram of a motor vehicle controller connected to a moment conversion unit according to an embodiment. [Diagram 2] 2 is a graph with a desired acceleration curve outputted by the controller according to FIG. 1 to a moment conversion unit using a method for determining a desired acceleration of a motor vehicle and outputting the determined desired acceleration. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0046] As can be seen from FIG. 1, a controller 1 is connected on the output side to a moment (torque) conversion unit 2, which is also connected on the output side to a motor vehicle (not shown).

[0047] The controller 1 is adapted to determine and subsequently output a target acceleration a_S of the motor vehicle, the controller 1 then being part of an adaptive cruise control enabling at least partially automated starting of the motor vehicle.

[0048] The moment conversion unit 2 is configured to receive the target acceleration a_S output from the controller 1, determine a target driving moment (torque) MSA and a target braking moment (torque) MSB based on the received target acceleration a_S, and output them to the motor vehicle so that the motor vehicle starts moving.

[0049] The individual steps P1 to P4 of the method for determining and outputting a target acceleration a_S of a motor vehicle for automated starting of a motor vehicle with adaptive cruise control, performed by the controller 1, are explained in more detail below with reference to FIG.

[0050] Initially, the motor vehicle is stopped (stationary), ie, not moving, and the actual speed of the motor vehicle is zero.

[0051] In a first step or phase P1 of the method, an increase of the setpoint acceleration a_S from a first value to a larger second value is performed.

[0052] Once said second value has been reached, in a second step or phase P2 of the method, the setpoint acceleration a_S is maintained at the second value for a predefined period of time by the controller 1. During the second phase P2, a ramp-up of the internal combustion engine of the motor vehicle is carried out.

[0053] The motor vehicle is stationary during the increase of the target acceleration from the first value to the second value and while the target acceleration is maintained at the second value, i.e. during the first and second steps P1, P2 of the method.

[0054] After a predetermined period of time has elapsed or after an increase in the internal combustion engine (speed) during the second stage P2 of the method, the controller 1 increases the target acceleration from the second value to the target acceleration value in a third step or third stage P3 of the method.

[0055] At the beginning of the third phase P3, the real motor vehicle start-up is initiated, ie the actual speed increases from zero to a positive value and the motor vehicle starts moving.

[0056] As can be seen from FIG. 2, the rate of increase (ascending gradient) of the target acceleration during the increase of the target acceleration from the first value to the second value, i.e. during the first stage P1 of the method, is greater than the rate of increase (ascending gradient) of the target acceleration during the increase of the target acceleration from the second value to the target acceleration value, i.e. during the third stage of the method.

[0057] In order to achieve a smooth transition to the target acceleration value, the rate of increase of the target acceleration decreases in the increasing transition towards the target acceleration value in the third stage P3, i.e. during the increase of the target acceleration from the second value to the target acceleration value.

[0058] In a fourth phase P4 or fourth step of the method, the target acceleration value is initially maintained and can then be adapted based on a target distance to other motor vehicles present around the motor vehicle. [Explanation of symbols]

[0059] 1 Controller 2 Moment conversion unit a_S Target acceleration MSA target driving moment MSB Target braking moment P1~P4 Method stages / steps t time

Claims

1. 1. A method for determining a target acceleration of a motor vehicle and outputting the determined target acceleration for automated launch of the motor vehicle by an adaptive cruise control, the method comprising: - increasing the target acceleration (a_S) from a first value to a second value (P1); - maintaining the target acceleration (a_S) at a second value (P2); and Increasing the target acceleration (a_S) from a second value to a target acceleration value (P3). A method comprising:

2. 2. The method according to claim 1, characterized in that the motor vehicle is stationary during the increase (P1) of the target acceleration (a_S) from the first value to the second value and during the maintenance (P2) of the target acceleration (a_S) at the second value.

3. 3. The method according to claim 1, further comprising the step of increasing the rotational speed of the internal combustion engine of the motor vehicle during the maintenance (P2) of the set acceleration (a_S) at the second value.

4. 3. The method according to claim 1 or 2, characterized in that after maintaining (P2) the target acceleration (a_S) at the second value and during the increase (P3) of the target acceleration (a_S) from the second value to the target acceleration value, the motor vehicle starts moving.

5. 3. The method according to claim 1 or 2, characterized in that the degree of increase of the target acceleration (a_S) during the increase (P1) of the target acceleration (a_S) from the first value to the second value is greater than the degree of increase of the target acceleration (a_S) during the increase (P3) of the target acceleration (a_S) from the second value to the target acceleration value.

6. 3. The method according to claim 1, wherein during the increase (P3) of the target acceleration (a_S) from the second value to the target acceleration value, the rate of increase of the target acceleration (a_S) decreases in the course of the increase towards the target acceleration value.

7. A controller (1), characterized in that it is adapted to carry out the method according to claim 1 or 2.

8. 8. A motor vehicle comprising: a controller (1) according to claim 7; and a moment conversion unit (2) connected to the controller (1), wherein the moment conversion unit (2) is configured to receive a target acceleration (a_S) output from the controller (1), and to determine a target driving moment (MSA) and / or a target braking moment (MSB) based on the received target acceleration (a_S), and to output the determined target driving moment (MSA) and / or a target braking moment (MSB) to the motor vehicle.

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