Patent Application
20210291796
This patent application claims priority to German Application No. 102020107883.8, filed Mar. 23, 2020, which is hereby incorporated herein by its reference in its entirety.
Adaptive cruise controls (ACC), which automatically regulate the rotational speed of an engine in such a way that a vehicle maintains a speed predetermined by the driver if possible, are known. Many vehicles often have a driver assistance system for assisting the driver in maintaining the current speed limit on the presently traveled road section, namely a so-called intelligence speed assistant or intelligent adaptive cruise control (IACC). The IACC reacts in this case to other vehicles, obstacles, and traffic signs in order to adapt the speed of the affected motor vehicle.
The present disclosure relates to controlling a braking process of a motor vehicle having an intelligent cruise control (IACC) and a motor vehicle for executing such control. The IACC is designed to execute braking processes automatically if a situation requiring a speed reduction occurs. Such situations are, e.g., an approach to diverse curves, to obstacles, or to other vehicles on the roadway. In the case of automatic braking, an IACC uses a braking profile. This braking profile is typically selected on the basis of certain criteria, for example with regard to the fuel economy and/or conveying an acceptable braking feeling for the driver and further occupants. Similar braking processes may feel different from braking executed by a human driver and may convey a less natural braking feeling. For example, braking processes which appear to begin relatively late could result in nervousness in the occupants.
In one example, a method for controlling a braking process of a driving motor vehicle having an intelligent cruise control and a navigation unit comprises:
The method is advantageous because phases having different deceleration values convey a braking feeling which better correspond to the braking of a human driver.
In the method, the braking process is preferably divided into three phases having different deceleration values. This has the advantage that the braking process can be controlled efficiently.
Preferably, in a first phase of the braking process, a deceleration of the speed which is lighter in relation to a constant braking process is exerted. In other words, the deceleration value in the first phase is less than in the case of a constant braking process. A correspondingly light deceleration initiates the braking process, so that the driver of the motor vehicle is made aware that a braking process is initiated in a timely manner. Trust in the automatic system is thus also built up. Moreover, it is also made clear to the driver that a situation which they have not yet perceived is upcoming which makes a speed reduction necessary.
Preferably, in a second phase of the braking process, a stronger deceleration in relation to a constant braking process is exerted. In other words, the deceleration value in the second phase is stronger than in the case of a constant braking process. In this phase, the speed is actively decelerated. After light braking in the first phase, this stronger deceleration corresponds to the behavior of a human driver. Moreover, the driver should now also be able to recognize the situation requiring a speed reduction.
Preferably, in a third phase, a lighter deceleration in relation to the second phase is exerted. In other words, the deceleration value in the third phase is less than in the second phase. This third phase is advantageous because the ability to control the braking process is enhanced. Moreover, an acceleration beginning after the braking process, for example in a curve, is facilitated since during the acceleration on the vertex of the curve, the transition from braking to acceleration is not so abrupt. Furthermore, the slower braking enables more time for the driver to survey a traffic situation which made the speed reduction necessary, for example in an intersection region.
The situation requiring a speed reduction can be ascertained based on data of the navigation unit. Route details such as intersections and curves of the calculated route are stored in the navigation unit. This embodiment of the method is therefore particularly suitable for decelerating before curves, intersections, and roundabouts.
In the method, the situation requiring a speed reduction also can be recognized by means of sensors of the motor vehicle. This is advantageous for recognizing obstacles not predictable on the basis of map information, for example stationary or slowly driving vehicles. The recognition sensors can be carried out both alternatively and also in combination with the recognition based on data of the navigation unit.
A curve can be ascertained as the situation requiring a speed reduction. The curve can be a slight curve, a bend, a hairpin bend into a winding road, or also a roundabout, without being restricted to this list. The curve is ascertained on the basis of items of map information which are stored in a storage unit of the navigation system or are available online (cloud). The curve can also be ascertained on the basis of GPS data, onboard environmental sensors, and/or by means of an optical imaging unit, for example a camera. Items of information which are obtained on the basis of a vehicle-to-vehicle communication or vehicle-to-infrastructure communication are also usable for detecting the curve.
A motor vehicle can include at least one navigation unit and one control unit, which is designed to control deceleration according to the method described herein.
The present disclosure is explained in greater detail on the basis of the figures. In the figures:
An embodiment of an example motor vehicle 1 is shown in
The motor vehicle 1 furthermore includes a camera 6 as an optical imaging unit. The camera 6 is capable of detecting obstacles which make a braking process necessary. Alternatively or additionally, the motor vehicle 1 can include further sensors, for example environmental sensors based on ultrasound, RADAR, or LIDAR. Furthermore, the motor vehicle 1 can be designed for vehicle-to-vehicle communication and/or vehicle-to-infrastructure communication.
In one example as illustrated in
The curve 8 is too steep to be able to be passed without braking (
In a fourth step S4, the programmed braking process is executed (see
In a second phase S4b, the motor vehicle 1 is strongly decelerated. Strong is to be understood here in relation to a constant braking process having uniform deceleration (
In a third phase S4c, the motor vehicle 1 is braked more lightly, wherein the deceleration is still stronger than in the case of a constant braking process (
| Number | Date | Country | Kind |
|---|---|---|---|
| 102020107883.8 | Mar 2020 | DE | national |
