Method for operating a vehicle having a driver assistance system intervening in a transverse dynamics of the vehicle

Abstract

A method for operating a vehicle having a driver assistance system intervening in a transverse dynamics of the vehicle, comprising the steps: detecting a driver intervention in a driving behavior of the vehicle due to an intervention of at least one actuator triggered by the driver assistance system; interpreting the driver intervention as an override of the intervention of the actuator; and reducing in a defined manner the intervention of the actuator as a function of the interpretation of the driver intervention in such a way that a driving task is returned to the driver in a controlled and defined manner.

Claims

1. A method for operating a vehicle having a driver assistance system that intervenes in a transverse dynamics of the vehicle, comprising: detecting a driver intervention in a driving behavior of the vehicle due to an intervention of at least one actuator triggered by the driver assistance system; interpreting the driver intervention as an override of the intervention of the actuator; and reducing in a defined manner, the intervention of the actuator, as a function of the interpretation of the driver intervention, so as to return a driving task to the driver in a controlled and defined manner, wherein the defined reduction of the intervention of the actuator is performed on the basis of a predictive mathematical model, and wherein the predictive model takes into account a current state of the vehicle and a current state of the driver.

2. The method as recited in claim 1, wherein the intervention, triggered by the driver assistance system, of the at least one actuator influences a guidance of the vehicle and includes at least one of a braking intervention, a steering intervention, and an intervention in a drive train of the vehicle.

3. The method as recited in claim 1, wherein a time characteristic of the defined reduction of the intervention of the at least one actuator is designed in accordance with a defined mathematical function.

4. The method as recited in claim 1, wherein the detection of the driver intervention is performed by detecting a reaction of the driver of the vehicle.

5. The method as recited in claim 4, wherein the detection of the driver intervention is performed by at least one of detecting a driver activity on a steering wheel of the vehicle, detecting a steering-wheel angle, detecting a steering-wheel angular velocity, detecting a steering torque, detecting an operation of an accelerator pedal of the vehicle, detecting an operation of a brake pedal of the vehicle, and detecting at least one of a facial expression and a gesture of the driver.

6. The method as recited in claim 1, wherein the defined reduction of the intervention includes withdrawing the intervention of the actuator over a predetermined time period.

7. A device for operating a vehicle having a driver assistance system that intervenes in a transverse dynamics of the vehicle, comprising: a detection device for detecting a driver intervention in a driving behavior of the vehicle due to an intervention of at least one actuator triggered by the driver assistance system; an interpretation device for interpreting the driver intervention as an override of the intervention of the actuator; and a reduction device for definably reducing the intervention of the actuator, as a function of the interpretation of the driver intervention, so as to return a driving task to the driver in a definably controlled manner, wherein the defined reduction of the intervention of the actuator is performed on the basis of a predictive mathematical model, and wherein the predictive model takes into account a current state of the vehicle and a current state of the driver.

8. A non-transitory computer-readable data carrier on which is stored program code for operating a vehicle having a driver assistance system that intervenes in a transverse dynamics of the vehicle, the program code, when executed by a computer, causing the computer to perform the following steps: detecting a driver intervention in a driving behavior of the vehicle due to an intervention of at least one actuator triggered by the driver assistance system; interpreting the driver intervention as an override of the intervention of the actuator; and reducing in a defined manner, the intervention of the actuator, as a function of the interpretation of the driver intervention, so at to return a driving task to the driver in a controlled and defined manner, wherein the defined reduction of the intervention of the actuator is performed as a function of a predictive mathematical model, and wherein the predictive mathematical model takes into account a current state of the vehicle and a current state of the driver, and wherein the predictive model takes into account a current state of the vehicle and a current state of the driver.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 a basic representation of a mode of operation of the provided method.

(2) FIG. 2 another basic representation of a mode of operation of the provided method.

(3) FIG. 3 another basic representation of a mode of operation of the provided method.

(4) FIG. 4 a basic sequence of a method for operating a vehicle having a driver assistance system intervening in the transverse dynamics.

(5) FIG. 5 a basic block diagram of a device for operating a vehicle having a driver assistance system intervening in a transverse dynamics of the vehicle.

DETAILED DESCRIPTION

(6) The term vehicle having a driver assistance system intervening in the transverse dynamics is understood in the following in such a way that the driver assistance system is used for assisting in or performing an evasive maneuver of the vehicle (e.g. in emergency situations, in lane-keeping, etc.). The steering intervention of the driver assistance system may be developed as a braking intervention and/or as a steering intervention and/or as an intervention in a drive train of the vehicle.

(7) The vehicle may be designed as an exclusively manually controlled, as a fully automated, partially automated, fully autonomous or partially autonomous motor vehicle.

(8) A central idea of the present invention is in particular to provide a method and a device in which a driver intervention in response to an intervention of the driver assistance system intervening in a transverse dynamics of the vehicle is detected and utilized in order to return a controllability of the vehicle to the driver in the event of great intervention intensities of the actuator because interpretation has determined that this corresponds to a wish of the driver. Here it is assumed that the vehicle fundamentally has a sensor system for monitoring the activity of the driver.

(9) Conventional assistance systems for vehicle guidance use maximum yaw rate changes of approx. 3°/s at 100 km/h and approx. 5°/s at 50 km/h. These target values were ascertained in the studies mentioned above in the related art. The investigation was based on faulty ESP interventions with maximum brake-pressure request, which were canceled at maximum gradients after a defined latency. In the process it turned out that in particular the cancellation of the fault at maximum gradients resulted in an overshooting value during the driver's compensation attempt and that at higher amplitudes it was rated as critical or as no longer controllable.

(10) The present invention provides for remedying this disadvantage to the greatest possible extent by taking the driver reaction into account in combination with a defined switch-off of the actuator intervention. In particular, the actuator intervention is not canceled at maximum gradients, but is initiated by the driver and reduced in an adapted manner. The adaptation occurs in a model-predictive manner, a predictive mathematical model of the vehicle being created by taking into account the current vehicle and driver state so that in this manner an optimized compensation of the system intervention and a safe state of the vehicle are provided. A withdrawal of the system intervention occurs in accordance with a mathematical function, for example in the form of a linear withdrawal, a suitable transfer function of a controlled system, etc.

(11) The method will be explained in greater detail below with reference to an exemplary scenario classified as controllable.

(12) In the manner explained, it is possible to compensate for braking interventions and/or steering interventions (front-axle steering, rear-axle steering, superimposition steering) of the automated vehicle.

(13) The defined withdrawal of the faulty actuator intervention is preferably designed according to a defined mathematical function, e.g. as a linear characteristic curve or as a response characteristic of a transfer element of control engineering (e.g. PT2 element). It is thus advantageously possible to implement a multitude of differently designed withdrawal functions.

(14) FIG. 1 shows a diagram explaining a mode of operation of the provided method. FIG. 1 shows time characteristics of yaw rates, a measured yaw rate y.sub.r,actual and a yaw rate y.sub.r,setpoint planned by the system being shown. The figure shows a time characteristic of the yaw rate y.sub.r,actual(t) of the vehicle that is generated in the process. A first maximum M1 of the yaw rate y.sub.r,actual(t) results from a braking intervention triggered correctly or erroneously by the driver assistance system. A second maximum M2 of the yaw rate y.sub.r,actual(t) arises by a superimposition of the actuator intervention with the withdrawal of the actuator intervention attenuated in accordance with the present invention and the effects due to the driver reaction.

(15) In this manner it is advantageously possible for the intervention yaw rate to be considerably higher than the currently applicable limit values (3°/s), which results in an increased functional use of the driver assistance system (e.g., evasion assistant) intervening in the transverse dynamics of the vehicle and controlled by the provided method, because it is possible to implement higher intervention intensities of said driver assistance system.

(16) The utilized withdrawal or switch-off algorithm and a detection and interpretation of the driver reaction required for this purpose may be implemented in various ways. To implement the withdrawal or switch-off algorithm, it is possible for example to perform a defined switch-off or withdrawal of the steering torque and/or a defined withdrawal of a drive torque in the drive train.

(17) Possible methods for detecting the driver reaction may be e.g. a detection of the brake pedal and/or accelerator pedal position and/or the steering wheel angular velocity and/or the steering torque. The detection of the steering wheel angular velocity is preferably performed by a sensor built into the steering wheel of the vehicle.

(18) FIG. 2 shows a time characteristic of a controlled variable of the system in the form of a brake pressure p.sub.b acting on a wheel of the vehicle, whereby an intervention in the transverse dynamics of the vehicle is achieved. In this concrete case, the brake system is used to control the vehicle. A time segment SE is shown, in which the actuator intervention occurs, as well as a switch-off period AB, in which the provided defined withdrawal of the actuator intervention is performed.

(19) Other possibilities of intervening in the movement of the automated vehicle are also conceivable in accordance with the present invention.

(20) For this purpose, the present invention provides for the driver, after a defined time, to counteract the braking intervention initiated correctly or erroneously, by a steering intervention and thereby to exceed a predefined threshold value of the steering wheel angular velocity. As a response to this, the present invention provides for the correctly or erroneously initiated braking intervention to be withdrawn in a defined manner within a parameterizable time period, whereby the brake pressure is definably reduced, whereby the task of driving is returned to the driver in a controlled manner.

(21) FIG. 3 shows a reaction of the driver on the steering wheel of the vehicle, which is expressed by a time characteristic of the steering wheel angular velocity ð(t). As mentioned, other detected driver reactions would also be conceivable such as for example changed positions of accelerator pedal and/or brake pedal, whose operations are detected by sensors, monitoring cameras, etc. for detecting a driver intention.

(22) At time t=0 s, the intervention into the transverse dynamics of the vehicle caused by the driver assistance system begins, whereby the vehicle is erroneously braked on one side so that at time t−0.4 s it begins to rotate. After approx. 0.55 s, the driver recognizes the movement of the vehicle and begins to steer counter to the rotation or to counteract the intervention. The present invention provides for the system to detect the driver's wish, to interpret it and thereby to start to abort the system intervention in a defined manner in that it withdraws the system intervention in a defined manner or switches it off slowly. For this purpose, there may be a provision to withdraw the brake pressure in a defined manner so that the driver is able to adjust to the change of the vehicle behavior and so that no overshooting value results in the compensation reaction and that the driver in the end remains in his own lane.

(23) The decisive point is that an intention of the driver to perform a countermeasure or driver reaction in response to the faulty actuator intervention is detected reliably, which is achieved e.g. by sensors and/or a camera directed toward the driver in the interior of the vehicle in order e.g. to detect a facial expression and/or a gesture of the driver. If a detection device implemented in this manner detects and interprets that the driver is about to override a faulty actuator system, a cancellation or retraction of the actuator intervention based on a predictive model is performed. This yields a stable overall system with the automated vehicle while taking the driver reaction into account.

(24) FIG. 6 shows a basic flow chart of one specific embodiment of the method of the present invention.

(25) In a step 100, the system detects a driver intervention in a driving behavior of the vehicle in response to an intervention of at least one actuator triggered by the driver assistance system.

(26) In a step 110, the system interprets the driver intervention as an override of the intervention of the actuator.

(27) In a step 120, the system reduces in a defined manner the intervention of the actuator as a function of the interpretation of the driver intervention in such a way that a driving task is returned to the driver in a definably controlled manner.

(28) FIG. 5 shows a block diagram of a specific embodiment of the provided device 200 for operating a vehicle having a driver assistance system intervening in a transverse dynamics of the vehicle.

(29) The figure shows an actuator device 300 (e.g. brake, steering system, drive train, etc.) for performing a transverse-dynamic intervention in a driving operation of the vehicle.

(30) Device 200 comprises a detection device 210 for detecting a driver intervention in a driving behavior of the vehicle due to an intervention of at least one actuator triggered by the driver assistance system. Detection device 210 is functionally connected to an interpretation device 220 for interpreting the driver intervention as an override of the intervention of the actuator. Interpretation device 220 is functionally connected to a reduction device 230 for definably reducing the intervention of the actuator as a function of the interpretation of the driver intervention, a control of the vehicle being thereby returned to the driver in a defined manner.

(31) Advantageously, the provided method may be implemented by a software program running on device 200, which supports making the method easily adaptable.

(32) One skilled in the art will suitably modify and/or combine with one another the features of the present invention without deviating from the essence of the present invention.