Driver assistance system having an emergency stop function which can be activated via a parking brake operator control element

Abstract

A driver assistance system has an emergency stop function for a motor vehicle. The motor vehicle has an electric parking brake. A parking-brake operating element is used to activate the electric parking brake. The driver assistance system is designed to activate an emergency stop function in accordance with the actuation of the parking-brake operating element and, as part of the emergency stop function, to perform an autonomous emergency stop driving maneuver for the emergency stopping of the vehicle. The driver assistance system is characterized in that the driver assistance system is designed to activate the emergency stop function only in response to an end of the actuation of the parking-brake operating element.

Claims

1. A system, comprising: a parking brake operator control element actuatable to activate an electric parking brake of the motor vehicle; and a control unit configured to activate an emergency stop function of the motor vehicle in response to an ending of an actuation of the parking brake operator control element to activate the electric parking brake, wherein the emergency stop function includes carrying out an autonomous emergency stop driving maneuver that brings the motor vehicle to a stop.

2. The system of claim 1, wherein the control unit is further configured to activate the electric parking brake, in response to and during the actuation of the parking brake operator control element, and independent of the emergency stop driving maneuver.

3. The system of claim 1, wherein the control unit is further configured to activate a lane keeping function for automatically keeping to a current lane, in response to the actuation of the parking brake operator control element.

4. The system of claim 3, wherein the lane keeping function is a lane keeping function without hands-on detection.

5. The system of claim 1, wherein the control unit is further configured to abort the emergency stop function in response to an operator control action to abort the emergency stop function.

6. The system of claim 5, wherein the parking brake operator control element is a switch which is actuatable in two different operator control directions, wherein the emergency stop function is activated in response to ending actuation of the switch in a first operator control direction, and wherein aborting the emergency stop function is in response to actuation of the switch in a second operator control direction.

7. The system of claim 6, wherein the two different operator control directions are a pushing and pulling of the switch.

8. The system of claim 1, wherein the autonomous emergency stop driving maneuver brings the motor vehicle to a stop on a roadway shoulder, starting from a current lane, via autonomous longitudinal guidance and transverse guidance.

9. The system of claim 1, wherein the control unit is further configured to: determine a variable characteristic of traffic volume by observing the surroundings of the vehicle, decide, as a function of the variable, between: (i) executing the emergency stop driving maneuver, whereby the motor vehicle is stopped in its present lane, or (ii) executing the emergency stop driving maneuver, whereby the motor vehicle is autonomously guided to and stopped on a shoulder of the roadway, and carry out the emergency stop driving maneuver in accordance with the decision.

10. The system of claim 9, wherein the variable is a traffic density variable or a traffic intensity variable.

11. The system of claim 9, wherein the control unit is further configured to: determine one or more time intervals between two vehicles, and determine the variable as a function of the one or more time intervals.

12. The system of claim 1, wherein the control unit is configured to decide whether to execute the autonomous emergency stop driving maneuver without transverse guidance.

13. The system of claim 12, wherein the decision of whether to execute the autonomous emergency stop driving maneuver without transverse guidance is based on detecting at least one of: lane boundaries and a preceding vehicle.

14. The system of claim 1, wherein the parking brake operator control element is a switch actuatable by pulling, and the emergency stop function is activated in response to ending the pulling of the switch.

15. The system of claim 1, wherein the control unit is further configured to: determine driver condition information relating to a current condition of a driver of the motor vehicle, in response to the actuation of the parking brake operator control element, or to the ending of the actuation of the parking brake operator control element, and in accordance with the driver condition information, to prohibit the activation of or abort the emergency stop function.

16. The system of claim 15, wherein the control unit is further configured to: decide, based on the driver condition information, whether to activate the emergency stop function, and in response to deciding not to activate the emergency stop function, prohibit the activation of or abort the emergency stop function.

17. The system of claim 15, wherein the control unit is further configured to determine the driver condition information via at least one of: a passenger compartment camera, and driver operator control elements for performing manual guidance of the vehicle.

18. The system of claim 1, wherein the motor vehicle comprises a comfort driver assistance system with at least one of: automatic longitudinal guidance and transverse guidance, and the control unit is configured to deactivate the comfort driver assistance system in response to the actuation of the parking brake operator control element.

19. A method for performing an emergency stop of a motor vehicle, comprising the steps of: activating an emergency stop function of the motor vehicle in response to an ending of an actuation of a parking brake operator control element, wherein the actuation of the parking brake operator control element activates an electric parking brake of the motor vehicle independent of the emergency stop function; and carrying out an autonomous emergency stop driving maneuver in accordance with the emergency stop function, so as to bring the motor vehicle to a stop.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 shows an exemplary embodiment of a driver assistance system according to the invention.

(2) FIG. 2 shows an exemplary flowchart.

(3) FIG. 3 shows exemplary time profiles of the actuation of the parking brake operator control element and of the vehicle acceleration.

DETAILED DESCRIPTION OF THE DRAWINGS

(4) FIG. 1 is a schematic illustration of a first exemplary embodiment of an inventive emergency stop assistance system NHA with an emergency stop function, which emergency stop assistance system NHA is integrated in a motor vehicle, in particular in a passenger car. The motor vehicle comprises an electric parking brake EMF and a parking brake operator control element BE for activating the electric parking brake EMF.

(5) The parking brake operator control element BE for activating the electric parking brake EMF is preferably a switch which is pulled by the operator in order to activate the electric parking brake EMF. For this purpose, for example the finger is engaged behind the edge K of the operator control part and the operator control part of the switch BE is pulled. The parking brake operator control element BE can preferably also be pressed in the opposite operator control direction, in order, for example, to deactivate the electric parking brake EMF.

(6) An emergency stop function of the emergency stop assistance system NHA can be activated as a function of the actuation of the parking brake operator control element BE, in the scope of which emergency stop assistance system NHA the vehicle then carries out an autonomous emergency stop driving maneuver to perform an emergency stop of the vehicle, for example on the shoulder.

(7) During the autonomous emergency stop driving maneuver, the longitudinal guidance and transverse guidance of the vehicle take place automatically. The emergency stop assistance system therefore assumes the vehicle guidance until the vehicle is brought to a stationary state. For this purpose, the emergency stop assistance system controls the drive A, the transmission G, the hydraulic service brake BB and the steering L via intermediate units (not illustrated).

(8) In order to plan and carry out the emergency stop driving maneuver, information on the surroundings of a surroundings sensor US, which observes the surroundings of the vehicle, is received.

(9) In the case of the exemplary emergency stop assistance system NHA, the emergency stop function does not already activate in reaction to actuation of the parking brake operator control element BE but rather activates only in reaction to ending of the actuation of the parking brake operator control element BE.

(10) The method of functioning of the exemplary emergency stop assistance system NHA is explained below in conjunction with FIG. 2 and FIG. 3.

(11) In step 100 of the flowchart in FIG. 2 it is detected that an operator (for example the driver or the front seat passenger) has started to actuate the parking brake operator control element BE. In FIG. 3, the actuation B_BE of the parking brake operator control element BE is illustrated. At the time t.sub.1 the actuation B_BE of the parking brake operator control element BE starts by the switch BE being pulled.

(12) In reaction to the actuation of the parking brake operator control element BE, the vehicle is braked, for example by means of the hydraulic service brake BB. This manual braking corresponds to the step 110 in FIG. 2. The acceleration a of the vehicle which is illustrated in FIG. 3 becomes negative here and reaches a particular maximum absolute value of the deceleration. The vehicle is decelerated further for as long as the parking brake operator control element BE continues to be actuated.

(13) Moreover, a comfort assistance system which happens to be active and which has automated transverse guidance, for example a lanekeeping assistant with a hands-on detection system, is automatically deactivated in reaction to the actuation of the parking brake operator control element BE.

(14) A lane keeping function without a hands-on detection system for automatically keeping to the current lane is activated in reaction to the actuation of the parking brake operator control element BE.

(15) This manual braking process and the activated lanekeeping function are understood not to be part of the emergency stop function according to the application.

(16) According to step 120, it is continuously checked whether the operator has ended the actuation of the operator control element BE.

(17) At the time t.sub.2, the operator ends the actuation of the parking brake operator control element BE; the switch BE is released.

(18) In reaction to ending of the actuation of the parking brake operator control element BE, the emergency stop function is activated (see step 130 in FIG. 2). The activation of the function is indicated to the driver, for example on a central display in the vehicle cockpit.

(19) The emergency stop function can, however, be aborted at any time after its activation, for example by actuation of a central operator control element. The abort facility is therefore indicated on a display in the vehicle cockpit. Alternatively, the emergency stop function can be aborted by pressing the switch BE. Furthermore, the emergency stop function can be aborted by actuating the accelerator pedal or the steering wheel.

(20) After the activation of the function, the vehicle is automatically decelerated in its own lane to a specific target speed v.sub.targ, e.g. v.sub.targ=100 km/h, if it does not already have a speed of v.sub.targ or less (see step 140). The maximum deceleration during the braking of the vehicle before the activation of the emergency stop function is higher than during the emergency stop maneuver.

(21) The transverse guidance specification for keeping to the lane during the braking is formed by lane markings; if the latter cannot be perceived by the vehicle, adjustment is performed with respect to the vehicle in front for the transverse guidance.

(22) At the time t.sub.3 the vehicle has reached the target speed v.sub.targ of 100 km/h.

(23) It is now decided whether the vehicle is to change autonomously onto the shoulder and stop there or alternatively stop on the current lane (see step 150 in FIG. 3).

(24) For this purpose, the traffic intensity q or some other variable which is characteristic of the traffic volume and which has been determined by previous observation of the surroundings of the vehicle by means of the surroundings sensor system US is used.

(25) In addition, further ambient conditions such as, for example, the type of road (freeway or country road) or the presence of lane boundaries can be taken into account in the decision.

(26) The variable q which is characteristic of the traffic volume is determined by averaging time intervals between vehicles. For example, the time interval to the vehicle in front, the time interval to the vehicle traveling directly behind the vehicle in question, the time intervals between detected objects in the lane to the left of the vehicle in question (if this lane is present) and the time intervals between detected objects in the lane to the right of the vehicle in question (if this lane is present) are determined for this purpose.

(27) The variable q which is characteristic of the traffic volume can then be determined as a function of the time intervals and the number of detected vehicles. The observation of the traffic volume is already carried out continuously before the actuation of the parking brake operator control element. The value of the variable q which is characteristic of the traffic volume can also already be calculated before the actuation of the parking brake operator control element.

(28) An exemplary decision strategy is described below:

(29) In the case of a freeway with relatively low traffic volume (q<q.sub.th) and lane boundaries which can be detected easily, an autonomous driving maneuver is carried out with one or more lane changes and stopping on the shoulder.

(30) In the case of a freeway with a relatively high traffic volume (q>q.sub.th) with or without detectable lane boundaries, stopping in the vehicle's own lane is carried out as an autonomous driving maneuver.

(31) In the case of a freeway without detectable lane boundaries and a vehicle in front which can be detected, stopping occurs in the lane of the vehicle in question.

(32) In the case of a freeway without lane boundaries and without a detectable vehicle in front deceleration to a stationary state is carried out without automatic transverse guidance.

(33) In the case of a country road or in town traffic with detectable lane boundaries or with a vehicle in front, stopping takes place in the lane of the vehicle in question.

(34) In the case of a country road or in town traffic without lane boundaries or without a vehicle which can be detected in front, deceleration to a stationary state takes place without transverse guidance.

(35) In addition to the autonomous driving maneuver, after the activation of the emergency stop function the flashing hazard warning light is activated. In addition, an emergency call to a call center is set up. Before the setting up of the emergency call, notification is given of the imminent setting up of the call and of the abort possibility. Moreover, when the emergency stop function is activated, one or more longitudinal safety assistance systems are activated, for example an automatic emergency brake assistant which assists or automatically initiates an emergency braking operation in the case of danger arising owing to an obstacle.

(36) If stopping on the shoulder has been selected as an emergency stop driving maneuver, the adjacent lane is monitored for rapidly overtaking vehicles, lateral risks of collision, and slow objects in front of the vehicle, and, insofar as is possible according to the monitoring, a slow lane change is carried out with the current speed (v.sub.targ or slower). The lane change is repeated, optionally, once or repeatedly until the vehicle has reached the shoulder (see time t.sub.4 in FIG. 3). The vehicle decelerates as far as the stationary state there, until the stationary state is reached at the time t.sub.5.

(37) If stopping in the vehicle's own lane has been selected, the vehicle is decelerated to a stationary state. The transverse guidance specification for keeping to the lane during this time is the roadway marking; if this cannot be detected, adjustment with respect to the vehicle in front is carried out. If the latter is not present or cannot be detected, deceleration to a stationary state is carried out without transverse intervention.

(38) If the vehicle is stationary, the transmission position P is automatically engaged, the central locking system unlocked and the interior light switched on, in order to draw attention to the driver; the flashing hazard warning light system remains activated. Moreover, the parking brake EMF can be engaged automatically.

(39) If the vehicle is stationary, the vehicle engine remains on, and an automatic engine stop which is otherwise triggered by an engine start/stop function is suppressed so that air-conditioning systems such as the passenger compartment heating system, seat heating system or the passenger compartment cooling system, if these were previously active, remain active until help arrives.

(40) The foregoing disclosure has been set forth merely to illustrate the invention and is not intended to be limiting. Since modifications of the disclosed embodiments incorporating the spirit and substance of the invention may occur to persons skilled in the art, the invention should be construed to include everything within the scope of the appended claims and equivalents thereof.