Method and system for compensating for an adverse manual steering intervention during an automated execution of an evasive maneuver

Abstract

The invention relates to a method for compensating for a disadvantageous manual steering intervention during an automated evasive maneuver of a vehicle. During the evasive maneuver, a wheel-specific braking intervention is initiated if an actual steering angle (δ ist ) of a steering wheel of the vehicle due to the manual steering intervention by an angle value above a predetermined limit value from a target steering angle (δ soll ) differs.

Description

[0001] The invention relates to a method for compensating for a disadvantageous manual steering intervention during the automated execution of an evasive maneuver by a vehicle. Furthermore, the invention relates to a system for compensating for a disadvantageous manual steering intervention during the automated execution of an evasive maneuver by a vehicle, comprising at least one emergency evasive assistance system that can be arranged on the vehicle and is configured to automatically execute an evasive maneuver by the vehicle, at least one braking system that can be arranged on the vehicle and is configured to automatically perform a wheel-specific braking intervention, at least one device for determining and / or detecting an actual steering angle of a steering wheel of the vehicle, and at least one vehicle electronics system connected to the emergency evasive assistance system, the braking system, and the device. State of the art

[0002] Active emergency steering systems (AES: Autonomous Emergency Steering; ESS: Evasive Steering Support) in vehicles can prevent accidents in some situations where accident avoidance is not possible using the vehicle's emergency braking systems. Existing developments for AES and ESS intervene in a vehicle's steering behavior via an electronic steering system (EPS: Electronic Power Steering). Due to a forced mechanical coupling of the steering wheel and the steering linkage of the wheels, a driver can influence the steering intervention of AES or ESS at any time. However, in frightening situations, drivers tend to exhibit incorrect steering behavior to avoid an accident, which impairs the steering intervention of AES or ESS.

[0003] DE 10 2016 219 757 A1 discloses a method for evasive maneuver assistance for a vehicle. The method includes detecting an evasive maneuver of the vehicle and applying an additional steering torque to increase the existing steering torque once the evasive maneuver has been detected. Furthermore, the method includes applying individual wheel braking of the vehicle to increase the vehicle's lateral offset. Disclosure of the invention

[0004] The invention relates to a method for compensating for a disadvantageous manual steering intervention during an automated evasive maneuver by a vehicle. This compensation makes it possible to compensate for disadvantageous driver steering reactions, i.e., driver misconduct, during the automated evasive maneuver of the vehicle. The wheel-specific braking intervention according to the invention can generate an additional yaw moment that compensates for the disadvantageous driver steering reaction, allowing the vehicle to follow an electronically determined or planned trajectory of the evasive maneuver. This significantly increases the functional benefit of an emergency evasive assistant used to execute the evasive maneuver.The evasive maneuver can be performed using a combined actuator system consisting of a vehicle's steering actuator and brake actuator, with the steering actuator acting as the primary actuator. A wheel-specific braking intervention refers to a braking intervention in which the vehicle's wheel brakes are controlled individually.

[0005] In the following, individual or specific parameters or their time profiles are mentioned as variables to be monitored. However, for the purposes of the invention, any combination of at least two such parameters or time profiles can also be monitored or used.

[0006] According to an advantageous embodiment, an actual steering angle of a steering wheel of the vehicle or a rotational speed of the steering wheel or a rotational acceleration of the steering wheel or a torque manually applied to the steering wheel is monitored as a parameter of the vehicle. A temporal profile of the actual steering angle or the rotational speed of the steering wheel or the rotational acceleration of the steering wheel or the torque manually applied to the steering wheel can also be monitored as a parameter and taken into account accordingly. Alternatively or additionally, environmental information can be used as a parameter, which is detected, for example, by means of vehicle sensors and is characteristic of a driving state of the vehicle. A driver steering reaction during the execution of the evasive maneuver can have a particularly disadvantageous orreducing lateral movement of the vehicle during the evasive maneuver if the driver's steering behavior adversely affects the steering wheel angle, for example, by deviating from the target steering angle required for the evasive maneuver by an angle value exceeding the specified limit. The sensitivity of the monitoring can be adjusted by selecting this limit. Other parameters could be the driver's attention and gaze direction, which are derived, for example, from the images captured by a "Driver Monitoring Camera," and / or the hand position on the steering wheel, which is estimated using sensors in the steering wheel (such systems are used, for example, for "hands-on" detection in automated driving functions).

[0007] According to a further advantageous embodiment, the wheel-specific braking intervention is continuously adjusted during the execution of the evasive maneuver, taking into account the current value of the parameter. This allows the additional yaw moment generated by the wheel-specific braking intervention to be continuously adjusted to a changing adverse steering intervention during the execution of the evasive maneuver, so that an optimal evasive maneuver is always performed.

[0008] According to a further advantageous embodiment, the wheel-specific braking intervention takes place taking into account predefined control and / or state variable restrictions. One control variable restriction can, for example, be a maximum brake pressure that the braking system can build up during an intervention. Another control variable restriction can, for example, be a maximum rate of pressure buildup in the braking system or a specific dynamic in the pressure buildup in the braking system. A state variable restriction can, for example, be a maximum lateral acceleration of the vehicle, a maximum lateral speed of the vehicle, or a rotational speed of the vehicle about its vertical axis (yaw axis). The dynamics of the braking intervention are preferably restricted such that the corresponding restrictions are observed.This will always result in reduced dynamics of the braking maneuver and the resulting vehicle reaction compared to a completely unconstrained system. The control and / or state variable constraints can therefore be determined by the vehicle's braking system and / or possible safety restrictions. Such safety constraints can primarily be abstractly formulated requirements for vehicle dynamics. Such a requirement could be, for example, "The vehicle should always remain in a stable driving state" or "The driving maneuver should be controllable for the average driver." Such requirements can then be translated into constraints on the state variables of a theoretical vehicle model.To comply with the specified control and / or state variable restrictions, a limit on the intensity of the braking intervention can be specified during the planning of the compensating wheel-specific braking intervention. Depending on the specified control and state variable restrictions as well as the vehicle condition (in particular, the current vehicle speed and the current steering angle), this results in a limitation of the achievable compensation.

[0009] According to a further advantageous embodiment, a target lateral offset of the vehicle for the evasive maneuver is determined, an adverse lateral offset resulting from the manual steering intervention is determined from the actual steering angle and a theoretical vehicle model, a lateral offset deviation of the adverse lateral offset from the target lateral offset is determined, a yaw moment for the evasive maneuver is determined taking into account the actual steering angle and the lateral offset deviation, and the wheel-specific braking intervention is carried out using the yaw moment. This solely compensates for adverse driver steering behavior, while other disturbances are not compensated. The target lateral offset of the vehicle for the evasive maneuver can be determined using a target trajectory, which can be determined from trajectory planning of an emergency evasive assistant of the vehicle.Using the desired lateral offset, the desired steering angle for the evasive maneuver can be determined. The lateral offset deviation can be determined by calculating the sum or the difference between the disadvantageous lateral offset and the desired lateral offset. The theoretical vehicle model can be configured to determine the vehicle's lateral offset with sufficient accuracy from a curve of the actual steering angle. Which additional vehicle states / information the vehicle model requires for this depends in particular on the specific application and the desired quality. As an example, a kinematic single-track model could be used as the model here. This has the steering angle and vehicle speed as input variables and the vehicle position and the orientation of the vehicle's longitudinal axis on the plane as output variables.Details of the model (“kinematic single-track model”) are known to those skilled in the art, for example from “Kinematic and dynamic vehicle models for autonomous driving control design”, Jason Kong et al., 2015, IEEE Intelligent Vehicles Symposium (IV), pages 1094-1099.

[0010] According to a further advantageous embodiment, a target lateral offset of the vehicle for the evasive maneuver is determined, an actual lateral offset of the vehicle is determined, a lateral offset deviation of the actual lateral offset from the target lateral offset is determined, a yaw moment for the evasive maneuver is determined taking into account the actual steering angle and the lateral offset deviation, and the wheel-specific braking intervention is carried out using the yaw moment. This makes it possible to compensate for both adverse driver steering behavior and other disruptive influences. The target lateral offset of the vehicle for the evasive maneuver can be determined using a target trajectory that can be determined from trajectory planning of an emergency evasive assistant of the vehicle. The target steering angle for the evasive maneuver can be determined using the target lateral offset.The lateral offset deviation can be determined by calculating the sum or the difference between the actual lateral offset and the desired lateral offset. By compensating for the deviations of the actually driven trajectory from the trajectory planned for the evasive maneuver, both adverse driver influences and other disturbances are corrected. Combined compensation thus combines the sole compensation of the driver's steering behavior with a classic trajectory control system, whose typical "steering system" actuator cannot be used or can only be used to a limited extent in this evasive situation due to the driver's disturbance. In the latter case, the "steering system" actuator can certainly be used, but it is now so severely disturbed by the driver that the trajectory control system may not be able to fulfill its task with the required quality requirements.

[0011] According to a further advantageous embodiment, the yaw moment is determined taking into account a further theoretical vehicle model. The further vehicle model can, for example, be modeled independently or generated by inverting the aforementioned theoretical vehicle model. A kinematic single-track model could again be used as a further theoretical vehicle model, but here expanded to include the yaw moment as an additional input variable. To calculate the yaw moment, the model is then inverted so that instead of the position and orientation of the vehicle from the steering angle and yaw moment, the yaw moment is calculated based on the deviations between the actual and target steering angle or the actual and target vehicle position and orientation. Accordingly, the yaw moment would be the output variable of the model, and the input variables would be the temporal profiles of the actual and target vehicle position and orientation.A concrete example of a simple inversion could be a linearized kinematic single-track model. Here, a linearized kinematic single-track model could be used with the relationship: Mz=Iz(ψ¨−νlδ˙) be used. M z a torque acting at the center of gravity of the vehicle around the vertical axis of the vehicle, I z the mass moment of inertia of the vehicle, ψ̈ the second time derivative of the angle between the x-axis of a stationary coordinate system and the longitudinal axis of the vehicle (yaw angle), v the vehicle speed, I the wheelbase of the vehicle and δ̇̇̇̇̇̇̇̇ the first time derivative of the steering angle.

[0012] The invention further relates to a system for compensating for a disadvantageous manual steering intervention during the automated execution of an evasive maneuver by a vehicle. The system comprises at least one emergency evasive assistance system that can be arranged on the vehicle and is configured to automatically execute an evasive maneuver by the vehicle. Furthermore, the system comprises at least one braking system that can be arranged on the vehicle and is configured to automatically perform a wheel-specific braking intervention. Furthermore, the system comprises at least one electronic device for determining and / or detecting an actual steering angle of a steering wheel of the vehicle.In addition, the system has at least one vehicle electronics unit connected to the emergency evasive maneuver assistance system, the braking system and the device, which is configured to monitor, during the execution of the evasive maneuver, whether at least one parameter of the vehicle is within a range determined by the emergency evasive maneuver and suitable for the evasive maneuver, and to control the braking system during the execution of the evasive maneuver to carry out a wheel-specific braking intervention if the parameter is not within the suitable range.

[0013] The system accordingly provides the advantages mentioned above with reference to the method. In particular, the system can be used to carry out the method according to one of the above-mentioned embodiments or a combination of at least two of these embodiments. Advantageous embodiments of the method can correspond to advantageous embodiments of the system, even if this is not explicitly mentioned below. The system according to the invention can be part of an electronic steering system or form it. Such an electronic steering system is thus a further subject matter of the invention.

[0014] According to an advantageous embodiment, the vehicle electronics are configured to continuously adjust the wheel-specific braking intervention while performing the evasive maneuver, taking into account the current steering angle. This embodiment provides the advantages mentioned above with reference to the corresponding embodiment of the method.

[0015] According to a further advantageous embodiment, the emergency evasive action assistance system is configured to determine a desired lateral offset of the vehicle for the evasive maneuver, wherein the vehicle electronics are configured to determine, from the actual steering angle and a theoretical vehicle model, an adverse lateral offset resulting from the manual steering intervention, to determine a lateral offset deviation of the adverse lateral offset from the desired lateral offset, to determine a yaw moment for the evasive maneuver taking into account the actual steering angle and the lateral offset deviation, and to control the braking system to carry out the wheel-specific braking intervention using the yaw moment. The advantages mentioned above with reference to the corresponding embodiment of the method are correspondingly associated with this embodiment.

[0016] According to a further advantageous embodiment, the emergency evasive action assistance system is configured to determine a desired lateral offset of the vehicle for the evasive maneuver, wherein the vehicle electronics are configured to determine an actual lateral offset of the vehicle, to determine a lateral offset deviation of the actual lateral offset from the desired lateral offset, to determine a yaw moment for the evasive maneuver taking into account the actual steering angle and the lateral offset deviation, and to control the braking system to perform the wheel-specific braking intervention using the yaw moment. This embodiment provides the advantages mentioned above with reference to the corresponding embodiment of the method.

[0017] In the following, the invention is explained by way of example with reference to the attached figures using preferred embodiments, wherein the features explained below can represent an advantageous and / or further developing aspect of the invention both individually and in different combinations of at least two of these features with one another. Short description of the characters

[0018] It shows: Fig. 1 is a flowchart of an embodiment of a method according to the invention; and Fig. 2 a flow diagram of a further embodiment of a method according to the invention. Detailed description of the characters

[0019] In the figures, identical or functionally identical components are provided with the same reference numerals. A repeated description of such components may be omitted in detail to avoid unnecessary repetition.

[0020] Fig. 1 shows a flowchart of an embodiment of a method according to the invention for compensating for a disadvantageous manual steering intervention during an automated execution of an evasive maneuver of a vehicle.

[0021] In method step 101, based on a target trajectory of the evasive maneuver determined by a trajectory planning of an emergency avoidance assistance system of the vehicle, a target lateral offset y soll of the vehicle for the evasive maneuver.

[0022] In method step 102, using the desired transverse offset y soll a target steering angle δ soıı for the evasive maneuver. In process step 103, the target steering angle δ soll manipulated or changed by the adverse manual steering intervention of a driver of the vehicle, so that a steering system of the vehicle determines the actual steering angle δ istrealized. The actual steering angle δ ist would lead to a deviation of the actual vehicle lateral offset from the desired lateral offset of the trajectory planning of the evasive maneuver.

[0023] In process step 104, the actual steering angle δ ist and a theoretical vehicle model, a disadvantageous lateral offset y resulting from the disadvantageous manual steering intervention of the driver Fahrer In method step 105, a transverse offset deviation Δy of the disadvantageous transverse offset y Fahrer from the target transverse offset y soll determined, which can be done by summing.

[0024] In process step 106, a yaw moment M z for the evasive maneuver taking into account the actual steering angle δ ist , the lateral offset deviation Δy and a theoretical inverse vehicle model. This yaw moment M zis used in method step 107 to initiate a wheel-individual braking intervention during the execution of the evasive maneuver if the actual steering angle δ ist a steering wheel of the vehicle deviates from the target steering angle δ determined for the evasive maneuver by an angle value exceeding a predetermined limit value due to the adverse manual steering intervention of the driver soll The wheel-individual braking intervention is therefore carried out using the yaw moment M z This allows the lateral offset deviation Δy caused by the driver's adverse manual steering intervention to be compensated. The wheel-specific braking intervention can be carried out taking into account predefined control and / or state variable restrictions.

[0025] The procedure allows a continuous adjustment of the wheel-individual braking intervention while the evasive maneuver is being carried out, taking into account the current actual steering angle δ ist take place.

[0026] Fig. 2 shows a flowchart of a further embodiment of a method according to the invention for compensating for a disadvantageous manual steering intervention during an automated execution of an evasive maneuver of a vehicle.

[0027] In method step 101, based on a target trajectory of the evasive maneuver determined by a trajectory planning of an emergency avoidance assistance system of the vehicle, a target lateral offset y soll of the vehicle for the evasive maneuver.

[0028] In method step 102, using the desired transverse offset y soll a target steering angle δ sollfor the evasive maneuver. In process step 103, the target steering angle δ soll manipulated or changed by the adverse manual steering intervention of a driver of the vehicle, so that a steering system of the vehicle determines the actual steering angle δ ist realized. The actual steering angle δ ist would lead to a deviation of the actual vehicle lateral offset from the desired lateral offset of the trajectory planning of the evasive maneuver.

[0029] In process step 108, an actual transverse offset y ist of the vehicle. In method step 109, a lateral offset deviation Δy of the actual lateral offset y ist from the target transverse offset y soll determined, which can be done by summing.

[0030] In process step 106, a yaw moment M z for the evasive maneuver taking into account the actual steering angle δ ist, the lateral offset deviation Δy and a theoretical inverse vehicle model. This yaw moment M z is used in method step 107 to initiate a wheel-individual braking intervention during the execution of the evasive maneuver if the actual steering angle δ ist a steering wheel of the vehicle deviates from the target steering angle δ determined for the evasive maneuver by an angle value exceeding a predetermined limit value due to the adverse manual steering intervention of the driver soll The wheel-individual braking intervention is therefore carried out using the yaw moment M z This allows the lateral offset deviation Δy caused by the driver's adverse manual steering intervention to be compensated. The wheel-specific braking intervention can be carried out taking into account predefined control and / or state variable restrictions.

[0031] The procedure allows a continuous adjustment of the wheel-individual braking intervention while the evasive maneuver is being carried out, taking into account the current actual steering angle δ ist take place. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2016 219 757 A1

[0003] Cited non-patent literature

[0000] Kinematic and dynamic vehicle models for autonomous driving control design”, Jason Kong et al., 2015, IEEE Intelligent Vehicles Symposium (IV), pages 1094-1099

[0009]

Claims

[1] Method for compensating for a disadvantageous manual steering intervention during an automated execution of an evasive maneuver of a vehicle, characterized by that during the execution of the evasive maneuver it is monitored whether at least one parameter of the vehicle is within a range suitable for the evasive maneuver, and that during the execution of the evasive maneuver a wheel-specific braking intervention is initiated if the parameter is not within the suitable range. [2] Method according to claim 1, characterized by that the vehicle parameter is an actual steering angle (δ ist ) of a steering wheel of the vehicle or a rotational speed of the steering wheel or a rotational acceleration of the steering wheel or a torque manually applied to the steering wheel is monitored. [3] Method according to claim 2, characterized bythat during the execution of the evasive maneuver, the wheel-individual braking intervention is continuously adjusted taking into account the current value of the parameter. [4] Method according to one of the preceding claims, characterized by that the wheel-individual braking intervention takes into account predefined control and / or state variable restrictions. [5] Method according to one of the preceding claims, characterized by that a desired transverse offset (y soll ) of the vehicle for the evasive maneuver is determined from the actual steering angle (δ ist ) and a theoretical vehicle model, a disadvantageous lateral offset (y Fahrer ), a transverse offset deviation (Δy) of the adverse transverse offset (y Fahrer ) from the target transverse offset (y soll ), a yaw moment (M z) for the evasive maneuver taking into account the actual steering angle (δ ist ) and the lateral offset deviation (Δy) is determined and the wheel-individual braking intervention is carried out using the yaw moment (M z ) is carried out. [6] Method according to one of claims 1 to 4, characterized by that a desired transverse offset (y soll ) of the vehicle for the evasive maneuver is determined, an actual lateral offset (y ist ) of the vehicle, a lateral offset deviation (Δy) of the actual lateral offset (y ist ) from the target transverse offset (y soll ), a yaw moment (M z ) for the evasive maneuver taking into account the actual steering angle (δ ist ) and the lateral offset deviation (Δy) is determined and the wheel-individual braking intervention is carried out using the yaw moment (M z ) is carried out. [7] Method according to claim 5 or 6, characterized by that the yaw moment (M z) is determined taking into account a theoretical inverse vehicle model. [8] System for compensating for a disadvantageous manual steering intervention during an automated execution of an evasive maneuver of a vehicle, comprising at least one emergency evasive assistance system which can be arranged on the vehicle and is designed to automatically carry out an evasive maneuver of the vehicle, at least one braking system which can be arranged on the vehicle and is designed to automatically carry out a wheel-individual braking intervention, at least one device for determining and / or detecting an actual steering angle (δ ist ) a steering wheel of the vehicle and at least one vehicle electronics connected to the emergency avoidance assistance system, the braking system and the device, characterized bythat the vehicle electronics are set up to monitor, during the execution of the evasive maneuver, whether at least one parameter of the vehicle is within a range determined by the emergency avoidance assistance system that is suitable for the evasive maneuver, and to control the braking system to carry out a wheel-individual braking intervention during the execution of the evasive maneuver if the parameter is not within the suitable range. [9] System according to claim 8, characterized by that the vehicle electronics are set up to continuously adapt the wheel-individual braking intervention while carrying out the evasive maneuver, taking into account the current actual steering angle (δ ist ). [10] System according to claim 8 or 9, characterized by that either the emergency avoidance assistance system is set up, a target lateral offset (y soll) of the vehicle for the evasive maneuver, whereby the vehicle electronics are set up to calculate the steering angle (δ ist ) and a theoretical vehicle model, a disadvantageous lateral offset (y Fahrer ), a transverse offset deviation (Δy) of the adverse transverse offset (y Fahrer ) from the target transverse offset (y soll ), a yaw moment (M z ) for the evasive maneuver taking into account the actual steering angle (δ ist ) and the lateral offset deviation (Δy) and to configure the braking system to carry out the wheel-individual braking intervention using the yaw moment (M z ) to be controlled; or the emergency avoidance assistance system is set up, a target lateral offset (y soll ) of the vehicle for the evasive maneuver, whereby the vehicle electronics are set up to determine an actual lateral offset (y ist) of the vehicle, a lateral offset deviation (Δy) of the actual lateral offset (y ist ) from the target transverse offset (y soll ), a yaw moment (M z ) for the evasive maneuver taking into account the actual steering angle (δ ist ) and the lateral offset deviation (Δy) and to configure the braking system to carry out the wheel-individual braking intervention using the yaw moment (M z ) to control.

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