Adaptive cruise control for motor vehicles and methods for adaptive cruise control

Abstract

Cruise control for a motor vehicle, with a stop-and-go system for automatic or driver-confirmed restarting after the motor vehicle has come to a standstill due to a preceding vehicle coming to a standstill and then starting up again, wherein the stop-and-go system enters a dynamic standstill state (t0 to t1) when the motor vehicle comes to a standstill, from which automatic dynamic restarting is possible, and wherein the stop-and-go system enters a confirmation standstill state (> t4) a preset time interval after the motor vehicle has come to and remained at a standstill, from which automatic restarting is only possible after driver confirmation. characterized by the fact that The confirmation standstill state (> t4) does not immediately follow the dynamic standstill state (t0 to t1), but occurs via at least one intermediate standstill state (t1 to t4) in which automatic restart is possible, wherein the intermediate standstill state (t1 to t4) differs from the dynamic standstill state (t0 to t1) by at least one of the following measures that tend to increase attention and / or starting safety: a) Generating at least one starting instruction at the beginning and / or during starting, wherein the instruction i) visual and / or ii) acoustic and / or iii) haptic, especially in the form of something consciously perceptible designed starting jerk; Nature can be; and / or b) Starting off with a lower acceleration of the motor vehicle than the maximum acceleration intended for restarting from a dynamic standstill (t0 to t1) or than the current acceleration of the vehicle ahead; and / or c) Starting with at least a temporary reduction in speed compared to starting from a dynamic standstill (t0 to t1), in particular in the form of at least one creep phase.

Description

[0001] The invention relates to a speed controller for a motor vehicle and a method for adaptive speed control in a motor vehicle according to the preambles of the independent claims.

[0002] The cruise control is a so-called adaptive cruise control, also called distance control cruise control, which takes into account the distance to a vehicle in front and its relative speed as additional feedback and control variables, and which can automatically accelerate back up to the speed set by the driver and which is also equipped with a so-called stop-and-go system for additional comfort in dense and stop-and-go traffic.

[0003] The stop-and-go system enables automatic or driver-confirmed restarting after a short standstill of the vehicle due to a vehicle ahead that has come to a standstill and then started moving again, either by tapping the accelerator pedal or by pressing a button or lever.

[0004] When the vehicle comes to a complete stop in this manner, the stop-and-go system enters a state subsequently referred to as a "dynamic standstill state," from which an automatic "dynamic" restart is possible, meaning a restart that follows the dynamics of the vehicle in front as closely as possible. After a preset time interval following the vehicle coming to a standstill and remaining stationary, the stop-and-go system enters a state subsequently referred to as a "confirmation standstill state," from which an automatic restart is only possible after explicit driver confirmation.

[0005] The invention also relates to a corresponding method for adaptive speed control in a motor vehicle depending on a distance to a vehicle ahead measured by a distance sensor, wherein the motor vehicle automatically follows the vehicle ahead until it comes to a standstill and, if necessary, i.e., if the vehicle ahead starts moving again, automatically starts moving again from such a standstill as long as the standstill time has not exceeded a predetermined period, or automatically starts moving again after confirmation by the driver of the motor vehicle, but not if such confirmation is omitted.

[0006] A speed controller and a method for adaptive speed control according to the preambles of the independent patent claims are known, for example, from DE 10 2005 022 676 A1 and DE 199 58 520 A1.

[0007] Modern motor vehicles primarily use radar sensors to measure distance and relative speed to a vehicle ahead. Lidar systems, for example, are alternatives.

[0008] The confirmation standstill state, from which automatic restart is only possible after driver confirmation, typically begins approximately 3 to a maximum of 5 seconds after the start of a standstill phase. This is designed so that after this time, a driver may no longer be aware that the stop-and-go system is active and may therefore no longer be paying attention to the traffic situation. This can be dangerous for vulnerable road users, such as pedestrians or cyclists crossing the road. The required confirmation makes the driver aware again that the stop-and-go system is active.

[0009] It has been shown that in practice the confirmation standstill state is entered very frequently, and the confirmation by the driver that is then necessary significantly reduces the comfort of the stop-and-go function.

[0010] The initial standstill state, from which automatic restart is possible, can in principle be extended beyond approximately 3 seconds, provided that the driver is attentive or if the vehicle is equipped with, for example, close-range monitoring using ultrasonic sensors, corner radar, and / or cameras. However, such sensors, as well as the additional hardware and software required to detect vulnerable road users, are very complex.

[0011] A longitudinal control system for a motor vehicle is known from DE 10 2014 201 544 A1. This longitudinal control system has a control unit for automatically controlling the speed or acceleration of the motor vehicle depending on the traffic situation ahead, from a standstill to a complete stop and from a standstill. Within a predetermined time interval after reaching a standstill, automatic starting without driver confirmation is permitted. This time interval can be variably set depending on the driver's level of attention. The time interval is shorter when the driver is inattentive. Furthermore, in the event of inattentiveness, the automatic restart can be announced in a timely manner via haptic feedback on the steering wheel.

[0012] DE 198 38 818 A1 discloses a gaze-controlled stop-and-go automatic system in motor vehicles. Forward movement is initiated solely by the driver consciously focusing their gaze on the section of road ahead for a defined period and is maintained for as long as this gaze is continued.

[0013] The invention is based on the objective of extending the period during which the motor vehicle can automatically restart in the known speed controller and method, without requiring additional sensors or exposing other road users to additional risks.

[0014] This problem is solved according to the invention by a speed controller and a method with the features of the independent claims.

[0015] Advantageous further developments of the invention are specified in the dependent patent claims.

[0016] According to the invention, the speed controller does not allow the confirmation standstill state to follow directly after the dynamic standstill state, but rather – provided the motor vehicle has not started moving again in the meantime – with the temporal interposition of a so-called “intermediate standstill state”, in which automatic restarting is still possible.

[0017] Starting off in this intermediate standstill state is characterized by at least one of the following measures that increase attention and / or starting safety: a) Generating at least one starting instruction at the beginning and / or during starting, wherein the instruction i) visual and / or ii) acoustic and / or iii) haptic, especially in the form of a consciously perceptible designed starting jerk; Nature can be; and / or b) Starting off with a lower acceleration of the motor vehicle than the maximum acceleration intended for restarting from a dynamic standstill (t0 to t1) or than the current acceleration of the vehicle ahead; and / or c) Starting with at least a temporary reduction in speed compared to starting from a dynamic standstill (t0 to t1), in particular in the form of at least one creep phase.

[0018] A "starting jerk" refers in particular to a short deceleration of the vehicle that is initiated directly after the first movement of the vehicle and is perceptible to the driver.

[0019] A creeping journey is understood to mean, in particular, a journey with no or only slight acceleration, e.g. up to 1 or 2 km / h, and such a creeping journey can typically last, e.g., 1 or 2 seconds.

[0020] For example, in the inventive method, the motor vehicle is briefly jerked forward as a haptic starting cue when the standstill time has exceeded the predetermined time period and the vehicle ahead starts moving again. The vehicle is then set into a slower forward motion than in a dynamic restart (i.e., compared to restarting at a time when the standstill time has not yet exceeded the predetermined time period t1).

[0021] Thus, the invention allows the driver to intuitively and therefore very quickly become aware that the stop-and-go system is still active and that they must keep an eye on the traffic situation. However, these measures are only taken when necessary and not during very short standstill intervals that are still within the dynamic standstill state, so that the driver does not feel bothered or "desensitized" by too many warnings with the concept according to the invention, and so that the driver still perceives the driving experience as smooth during short standstill intervals.

[0022] Because the additional measures are only taken after a certain standstill interval, the driver intuitively recognizes their warning function, which might not be the case if these additional measures were taken even at arbitrarily short standstill intervals.

[0023] Furthermore, a vehicle that, for example, accelerates with a brief jerk and then very slowly, effectively warns other road users not to step into the road in front of the vehicle. If a pedestrian or cyclist is already there, they can recognize the danger and, if necessary, easily move to safety. The maximum possible speeds and accelerations for automatic restarts from a standstill should also be based on this principle.

[0024] In a preferred embodiment, the application and intensity of measures a) to c) are varied depending on the time spent in the intermediate standstill state (t1 to t4) until restarting, such that the measures tend to generate greater attention and / or greater starting safety as the duration of the intermediate standstill state (t1 to t4) increases.

[0025] For this purpose, the intermediate standstill state (t1 to t4) can be subdivided or cascaded into successive phases (t1 to t2, t2 to t3, t3 to t4), in each of which automatic restart is still possible, with the phases differing in terms of the use and / or intensity of the measures a) to c).

[0026] Alternatively, instead of the aforementioned phase division, it is also conceivable to continuously vary certain characteristic quantitative parameters of measures a) to c), e.g., volume of an acoustic indication, strength of a haptic indication ("jerking"), degree of reduction of acceleration, speed reduction and duration for a creeping section, number of creeping sections, etc., according to a function depending on the duration of the standstill until restarting.

[0027] In the case of phase division or cascading, the intermediate standstill state can be divided into two or more phases, where, for example, - a first phase (t1 to t2) of the intermediate standstill state may include at least a starting indication and a starting with a lower acceleration than from the dynamic standstill state (t0 to t1); - a second phase (t2 to t3) of the intermediate standstill state, which begins after the first phase, may include at least one start-up phase with lower acceleration than in the first phase and may also include a creep phase; and - an optional third phase (t3 to t4) of the intermediate standstill state, which begins after the second phase, may include at least one additional starting instruction following the creep phase, in particular a haptically perceptible starting jolt.

[0028] This classification, however, is merely an example. The application and gradation of the aforementioned measures can be varied in many ways and, in principle, adapted to the specific driving situation (e.g., differentiating between stop-and-go situations in city traffic and on highways, where unexpectedly appearing road users such as cyclists or pedestrians are less common).

[0029] In preferred embodiments, the stop-and-go system switches from the dynamic standstill state to the intermediate standstill state between 2 and 4 seconds, and preferably 3 seconds, after the vehicle has come to a standstill and remained stationary.

[0030] Within the scope of the invention, the stop-and-go system typically switches from the intermediate standstill state to the confirmation standstill state after a certain time, from which automatic restarting is only possible after driver confirmation.

[0031] In preferred embodiments, the stop-and-go system switches from the first phase of the intermediate standstill state to a second phase of the intermediate standstill state between 6 and 10 seconds after the vehicle has come to a standstill.

[0032] In preferred embodiments, the stop-and-go system switches from the second phase of the intermediate standstill state to a third phase of the intermediate standstill state between 12 and 18 seconds after the vehicle has come to a standstill, and to the confirmation standstill state between 5 and 10 seconds later.

[0033] The starting procedures corresponding to the respective standstill states are thus cascaded over time, becoming increasingly less dynamic than in the dynamic standstill state and increasingly involving the driver, with the automatic starting from state to state occurring more slowly.

[0034] The driver can terminate any of these starting procedures at any time by applying the vehicle brakes if he considers the situation unsafe, e.g. because another road user is crossing.

[0035] In addition, in one embodiment of the invention, the driver can return to a dynamic standstill state at any time by actuating a control element (e.g. a button labeled “RES” or “Resume”, a lever or a corresponding touchscreen command field or other input element) or, for example, by a voice command, which enables him to start dynamically.

[0036] The cascaded start-up procedures improve the driver's chances of recognizing unsafe situations as the standstill time increases, to the extent that the driver may no longer be aware that the stop-and-go system is active.

[0037] In preferred embodiments, the motor vehicle includes an optical display which shows different symbols depending on whether the stop-and-go system is in the dynamic or confirmation standstill state or in one of the intermediate standstill states, which clarify the corresponding standstill state and optionally also differ according to whether the vehicle ahead is stationary or starting to move.

[0038] The following is a description of exemplary implementations based on the drawings. These show: Fig. 1. A sketch illustrating different standstill states of an adaptive speed controller for a motor vehicle; Fig. 2 graphs of different startup procedures from the in Fig. 1. Standstill states shown; and Fig. 3 a sketch of different status indicators in the in Fig. 1. Standstill states shown.

[0039] An adaptive cruise control system includes a stop-and-go system for automatic or driver-approved restarting after the vehicle has come to a standstill due to a preceding vehicle coming to a standstill and then starting again.

[0040] If the motor vehicle comes to a standstill in this manner, namely at a time t0 in Fig. 1. The stop-and-go system is in a dynamic standstill state, so named because of the possibility of automatic dynamic restarting. From this state, automatic restarting is possible if the vehicle in front (in Fig. 2 and Fig. (3. Destination mentioned) starts moving again.

[0041] If the vehicle ahead has not yet started moving and the vehicle is still stationary at time t1, for example 3 seconds after t0, the stop-and-go system enters a first phase of a so-called intermediate standstill state, also known as "Delayed Start Phase 1". If, in this state, the vehicle ahead starts moving again, the vehicle automatically resumes movement, which includes a slight jolt and otherwise occurs with less acceleration than during a dynamic start.

[0042] This is in Fig. Figure 2 illustrates the acceleration during automatic restart from various standstill states as a function of the time elapsed after time t0 or the standstill time t. The initial jerk is shown as a small bump at the beginning of the acceleration / time curve.

[0043] Furthermore, an acoustic warning can be given using the vehicle's on-board speakers, as described in Fig. Figure 2 illustrates this. If this warning is given in temporal relation to a vehicle jolt, this acoustic warning may represent a sound typical of a vehicle jolt, thus increasing the perceptibility of the vehicle jolt; however, it may also be a common warning tone (e.g. a "chime" tone signal) or a voice message or the like.

[0044] If the vehicle ahead does not start moving during Phase 1 and the vehicle is still stationary at time t2, e.g., 8 seconds after t0, the stop-and-go system enters a second phase of intermediate standstill, also known as "Delayed Start Phase 2". If the vehicle ahead starts moving again in this state, the vehicle automatically resumes movement, which includes a slight jolt and even less acceleration than in Phase 1, as well as a brief crawl, e.g., no or only slight acceleration at up to 1 or 2 km / h, immediately after the jolt.

[0045] If the vehicle ahead does not start moving during phase 2 and the vehicle is still stationary at time t3, e.g., 15 seconds after t0, the stop-and-go system enters a third phase of intermediate standstill, also known as "delayed start phase 3". If the vehicle ahead starts moving again in this state, the vehicle automatically restarts, which includes a slight initial jerk, a brief creep, and acceleration similar to that in phase 2, as well as at least one further initial jerk immediately after the creep.

[0046] If the vehicle ahead does not start moving during phase 3 and the vehicle is still stationary at time t4, e.g., 22 seconds after t0, the stop-and-go system enters a confirmation standstill state. Automatic restarting from this state is only possible if the driver confirms it, e.g., by tapping the accelerator pedal or pressing a button. Alternatively, further graduated phases of the intermediate standstill state can be provided.

[0047] The different standstill states can be displayed to the driver on a visual display on the dashboard using different symbols, which clarify the corresponding standstill state and optionally also differentiate between whether the vehicle in front is stationary or is starting to move.

[0048] As in Fig. 3 shown, the driver of the motor vehicle (in Fig. 1 and Fig.3. Host) during the dynamic start-up phase, for example, an unlabeled symbol for a vehicle ahead is displayed, regardless of whether the vehicle ahead (the target of the speed control) is stopped or starting up.

[0049] During phases 1 to 3 of the intermediate standstill state, the same symbol is displayed to the driver, but with a label indicating readiness for safe acceleration when the destination is stopped, and indicating that safe automatic acceleration is active when the destination is moving and that the driver can end this acceleration procedure and continue with normal dynamic acceleration by pressing a "RES(ume)" button. This may be desirable for the driver if they find the safe automatic acceleration unnecessarily slow.

[0050] If the vehicle is still stopped after phase 3, the same symbol is displayed to the driver, but with a label indicating the stopped state if the destination is stopped and indicating that the driver must press the "RES(ume)" button if they wish to continue the journey if the destination is approaching or no longer exists.

Claims

[1] Speed ​​controller for a motor vehicle, with a stop-and-go system for automatic or driver-confirmed restarting after the motor vehicle has come to a standstill due to a preceding vehicle coming to a standstill and then starting up again, wherein the stop-and-go system enters a dynamic standstill state (t0 to t1) when the motor vehicle comes to a standstill, from which automatic dynamic restarting is possible, and wherein the stop-and-go system enters a confirmation standstill state (> t4) a preset time interval after the motor vehicle has come to and remained at a standstill, from which automatic restarting is only possible after driver confirmation, characterized by , that The confirmation standstill state (> t4) does not immediately follow the dynamic standstill state (t0 to t1), but occurs via at least one intermediate standstill state (t1 to t4) in which automatic restart is possible, wherein the intermediate standstill state (t1 to t4) differs from the dynamic standstill state (t0 to t1) by at least one of the following measures that tend to increase attention and / or starting safety: a) Generating at least one starting instruction at the beginning and / or during starting, wherein the instruction i) visual and / or ii) acoustic and / or iii) haptic, especially in the form of something consciously perceptible designed starting jerk; Nature can be; and / or b) Starting off with a lower acceleration of the motor vehicle than the maximum acceleration intended for restarting from a dynamic standstill (t0 to t1) or than the current acceleration of the vehicle ahead; and / or c) Starting with at least a temporary reduction in speed compared to starting from a dynamic standstill (t0 to t1), in particular in the form of at least one creep phase. [2] Speed ​​controller according to claim 1, characterized by , that the application and intensity of measures a) to c) are varied depending on the time spent within the intermediate standstill state (t1 to t4) until restarting, such that with increasing duration of the intermediate standstill state (t1 to t4) until restarting, the measures tend to generate greater attention and / or greater starting safety. [3] Speed ​​controller according to claim 2, characterized by , that the intermediate standstill state (t1 to t4) is subdivided or cascaded into successive phases (t1 to t2, t2 to t3, t3 to t4) in each of which automatic restart is still possible, with the phases differing in terms of the use and / or intensity of the measures a) to c). [4] Speed ​​controller according to claim 3, characterized by that the intermediate standstill state is subdivided or cascaded into two or more phases, wherein - a first phase (t1 to t2) of the intermediate standstill state includes at least a starting indication and a starting with a lower acceleration than from the dynamic standstill state (t0 to t1); - a second phase (t2 to t3) of the intermediate standstill state, which begins after the first phase, includes at least one start-up phase with lower acceleration than in the first phase and additionally a creep phase; and - an optional third phase (t3 to t4) of the intermediate standstill state, which begins after the second phase, includes at least one additional starting instruction following the creep phase, in particular a haptically perceptible starting jolt. [5] Speed ​​controller according to any one of claims 1 to 4, characterized by , that the stop-and-go system switches from the dynamic standstill state (t0 to t1) to the intermediate standstill state (t1 to t4) between 2 and 4 seconds after the vehicle has come to a standstill. [6] Speed ​​controller according to claim 4 or 5, characterized by, that the stop-and-go system switches from the first phase of the intermediate standstill state (t1 to t2) to the second phase of the intermediate standstill state (t2 to t3) between 6 and 10 seconds after the vehicle has come to a standstill. [7] Speed ​​controller according to any one of claims 4 to 6, characterized by , that the stop-and-go system switches from the second phase of the intermediate standstill state (t2 to t3) to the third phase of the intermediate standstill state (t3 to t4) between 12 and 18 seconds after the vehicle has come to a standstill, and switches to the confirmation standstill state (> t4) between 5 and 10 seconds later. [8] Speed ​​controller according to any one of the preceding claims, characterized by , that the acoustic starting instruction includes a tone signal and / or an acoustic accentuation of this starting jolt, coordinated in time with a haptic starting jolt. [9] Speed ​​controller according to any one of the preceding claims, characterized by , that the motor vehicle has an optical display which shows different symbols depending on whether the stop-and-go system is in the dynamic standstill state (t0 to t1) or in the confirmation standstill state (> t4) or in any of the intermediate standstill states (t1 to t2, t2 to t3, t3 to t4), which clarify the corresponding standstill state and optionally also differ according to whether the vehicle in front is stationary or is starting to move. [10] Method for adaptive speed control of a motor vehicle depending on a distance to a vehicle ahead measured by a distance sensor, wherein the motor vehicle automatically follows the vehicle ahead until it comes to a standstill and, if necessary, automatically starts moving again from such a standstill as long as the standstill time (t) has not exceeded a predetermined time period (t1 - t0), or automatically starts moving again after confirmation by the driver of the motor vehicle, characterized by , that, If the standstill time (t) has exceeded the predetermined time interval (t1 - t0) and the vehicle ahead starts moving again, in an intermediate standstill state (t1 to t4) in which automatic restarting without driver confirmation occurs, one or more of the following measures, which increase attention and / or starting safety and which differ from the measures taken during automatic restarting before the predetermined time interval, are taken: a) Generating at least one starting indicator at the beginning and / or during starting, which i) visual and / or ii) acoustic and / or iii) haptic, especially in the form of something consciously perceptible designed starting jerk; Nature can be; and / or b) Starting off with a lower acceleration of the motor vehicle than the maximum acceleration intended for restarting from a dynamic standstill (t0 to t1) or than the current acceleration of the vehicle ahead; and / or c) Starting off with at least a temporary reduction in speed compared to starting off from a dynamic standstill, in particular in the form of one or more creeping phases.

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