situation-dependent restrictions on steering behavior

Abstract

A method is disclosed for calculating a situation-dependent limit on a steering torque and / or for calculating control instructions for a steering system of a vehicle by a controller, wherein data on the surroundings of the vehicle, data on a planned trajectory and / or data from sensors of the vehicle are received, a driving situation of the vehicle is derived from the received data, a situation-dependent limit on a steering behavior, such as for example a steering torque, is calculated from the derived driving situation, and control instructions for aligning the calculated situation-dependent limit on the steering behavior are output. Furthermore, a controller, a computer program and a machine-readable storage medium are disclosed.

Description

Technical Field

[0001] This invention relates to a method for calculating, in relation to conditions, limits on steering torque and / or control commands for a vehicle's steering system. Furthermore, this invention relates to a controller, a computer program, and a machine-readable storage medium. Background Technology

[0002] According to the BASt standard, driver assistance systems classified as assisted or partially automated use electric servo steering for lateral vehicle guidance. The actuators of the electric servo steering system can also intervene in steering without driver assistance and, for example, automatically keep the vehicle within its lane. Furthermore, in these driver assistance systems, the driver is responsible for guiding the vehicle and must take over vehicle guidance in the event of a malfunction or erroneous intervention of the driver assistance system.

[0003] When developing and calibrating such driver assistance systems, steering performance and the level of steering automation are inconsistent with vehicle controllability in the event of system errors. Higher steering torque jumps or gradients correlate with lower controllability.

[0004] To ensure vehicle controllability while driver assistance systems are activated, maximum steering torque and maximum steering torque gradient are typically limited. However, such limitations are problematic because the reduced steering performance may render the steering torque insufficient for navigating narrow curves, requiring the driver to actively assist the driver assistance system. Furthermore, in future driver assistance systems with higher levels of automation, limited steering performance will be insufficient for hands-free driving. Summary of the Invention

[0005] The objective upon which this invention is based can be viewed as proposing a method for adapting control commands for a steering system in a situation-dependent manner.

[0006] This task is solved by means of the subject matter of the present invention. Advantageous configurations of the present invention are the contents of various preferred embodiments.

[0007] According to one aspect of the invention, a method is provided for calculating, in relation to conditions, a limit on steering torque by a controller and / or for calculating control commands for the steering system of a vehicle. In particular, the steering behavior of the vehicle can be set by a driver assistance system to achieve the highest possible steering performance while maintaining the highest possible controllability.

[0008] In one step, data about the vehicle's surrounding environment, the planned trajectory, and / or data from the vehicle's sensors are received. The vehicle's driving condition is determined based on the received data. This driving condition can be determined to estimate the desired vehicle steering behavior. For example, a higher steering torque can be expected for a turning driving condition than for a straight driving condition. Alternatively or additionally, external data or so-called non-vehicle data, such as map data, may also be received in addition to the data about the vehicle's surrounding environment.

[0009] Based on the desired driving conditions, condition-related limits on steering behavior, such as steering torque, are calculated. Here, the calculation of condition-related limits can be set for the vehicle behavior desired by the driver. Steering behavior here refers to all control commands and interventions that have an active or passive effect on the vehicle's steering system.

[0010] In the next step, output control commands are used to set calculated, condition-dependent limits on steering behavior. Alternatively, the controller can generate and output a large number of control commands to impose corresponding limits on the vehicle's steering behavior.

[0011] Information about the restrictions and / or about the identified driving conditions can optionally be transmitted to the driver assistance system, where appropriate consideration can be made.

[0012] This method can be implemented in the form of an intelligent and situation-dependent steering torque limiter for driver assistance systems. Based on the actual expected steering torque demand in the situation, situation-dependent limitation of permissible adjustable steering behavior, such as steering torque, can achieve higher steering performance with the same or improved driver controllability.

[0013] This method allows for steering torque, for example, in straight-ahead driving conditions, to be only as much as is normally required to maintain straight-ahead driving and to compensate for disturbances such as ruts or crosswinds.

[0014] In addition, the vehicle's driving conditions can be considered, such as parking, slow turning, fast turning, straight driving on single-lane or multi-lane roads, and similar situations.

[0015] According to another aspect of the invention, a controller is provided, wherein the controller is configured to implement the method. The controller may be, for example, a vehicle-side controller, an external vehicle controller, or an external server unit, such as a cloud system.

[0016] Furthermore, according to one aspect of the invention, a computer program is provided, comprising instructions that, when executed by a computer or controller, arrange the computer or controller to perform the method according to the invention. According to another aspect of the invention, a machine-readable storage medium is provided, on which the computer program according to the invention is stored.

[0017] Vehicles can operate assistedly, partially automatically, highly automatically, and / or fully automatically or without a driver, according to BASt standards.

[0018] Vehicles can be, for example, passenger cars, trucks, autonomous taxis, and similar vehicles. Vehicles are not limited to those operating on roads. More precisely, vehicles can also be configured as watercraft, aircraft, such as transport drones, and the like.

[0019] According to one embodiment, in order to determine the driving conditions, driving condition data is received, such as vehicle speed, yaw rate, lateral acceleration or steering angle, current and planned vehicle trajectory, direction of the lanes traversed, behavior of adjacent traffic participants, identified traffic signs and / or future lane directions obtained from map data. Here, these input parameters can be used individually or in arbitrary combinations for condition recognition.

[0020] According to another embodiment, driving conditions and situation-related constraints on steering behavior are obtained through a vehicle model. This allows for model-based pre-control within a control loop, which utilizes knowledge of the control segment to improve control quality. To determine or calculate appropriate situation-dependent constraints on steering behavior, a physical vehicle model or an empirical vehicle model can be used. Here, the vehicle model can be configured as a simplified single-lane model or a more complex model with a broader consideration of the vehicle's environment.

[0021] According to another embodiment, driving conditions and condition-related limitations on steering behavior are determined based on historical data, application-specific data, and / or statistical data. This measure allows for the utilization of knowledge about the road segment being adjusted or the road section ahead, thereby improving the controllability of system errors. Here, historical data and / or statistical data, stored offline, online, or in the cloud, can be used, for example.

[0022] According to another embodiment, existing restrictions on steering torque and / or steering gradient are broadened or narrowed by imposing situation-dependent limitations on steering behavior. This allows for practical restrictions on vehicle steering behavior in vastly different ways. For example, this method can enable the situation-dependent expansion or narrowing of the limit values ​​of existing limiters.

[0023] According to another embodiment, lower and upper limit values ​​are calculated and set for situation-related restrictions on steering behavior. Therefore, the restrictions on steering behavior can be implemented based on the situation-related upper and lower limits calculated from the required signal. The required signal can preferably be used to set the steering motion performed by the driver assistance system. This required signal can be changed by limiting it to achieve adaptation to the steering behavior. Here, increasing or decreasing the required value can achieve situation-related adaptive steering behavior.

[0024] According to another embodiment, condition-related restrictions on steering behavior are set by output control commands in a manner that limits the steering torque on the steering wheel, EPS motor, and / or at least one wheel. Therefore, the restrictions can be applied directly to the steering tie rod or the vehicle's side steering mechanism. For this purpose, for example, an actuator can be manipulated to induce or inhibit steering wheel movement.

[0025] According to another embodiment, condition-related limitations on steering behavior are calculated as force boundaries, angle boundaries, and / or position boundaries and set by the output control commands. Here, the appropriate signals for limiting the vehicle steering system can be achieved by limiting the torque at any level, such as the vehicle's steering wheel, EPS motor, or the wheel being steered.

[0026] Furthermore, the maximum force acting on the rack, tie rod, steering link, or the wheel being steered can be affected by limiting the steering behavior of the driver assistance system.

[0027] Restrictions on steering behavior can be achieved by setting the angles of any part of the vehicle, such as the steering wheel angle, the EPS motor angle, or the angle of the wheel being steered.

[0028] Furthermore, the degrees of freedom of motion at possible locations and arbitrary parts, such as the rack, can be restricted by limiting steering behavior. Attached Figure Description

[0029] The preferred embodiments of the invention are described in more detail below with reference to strongly simplified schematic diagrams.

[0030] Here it is shown:

[0031] Figure 1 A schematic diagram of the vehicle is shown, and

[0032] Figure 2 A schematic diagram is shown to visually illustrate a flowchart according to one embodiment of the method. Detailed Implementation

[0033] Figure 1A schematic diagram of vehicle 1 is shown. Vehicle 1 may be, for example, a vehicle that can operate automatically or partially automatically. In particular, vehicle 1 is configured to implement at least one driving assistance function.

[0034] The driving assistance function is used to adjust the lateral guidance of vehicle 1. For this purpose, for example, the actuator 4 of the electronic servo steering system 6 can be operated by the controller 2 through control commands.

[0035] Vehicle 1 has sensors 8 and 10 to scan the environment U and determine the characteristics of vehicle 1. For this purpose, vehicle 1 may have environmental sensors 8, such as lidar sensors, camera sensors, or radar sensors.

[0036] In addition, a status sensor 10 is provided to obtain measurement data about the vehicle's status, such as an acceleration sensor, a yaw and rotation rate sensor, a steering angle sensor, and similar sensors.

[0037] Additionally, a GNSS sensor may be installed in vehicle 1 to determine the location of vehicle 1 within environment U.

[0038] Sensors 8 and 10 are connected to controller 2 via data transmission. Therefore, controller 2 can receive, analyze, and evaluate the measurement data from sensors 8 and 10. For example, driving conditions can be determined based on the received measurement data.

[0039] To determine driving conditions, driving status data can be received, such as vehicle speed, yaw rate, lateral acceleration, or steering angle; current and planned vehicle trajectory; lane direction; behavior of adjacent road users; identified traffic signs; and / or future lane direction derived from map data. These input parameters can be used individually or in arbitrary combinations to identify driving conditions.

[0040] Depending on the configuration of vehicle 1, situation-related restrictions on the steering behavior of vehicle 1 can be set. This can be done automatically by controller 2. In particular, situation-related restrictions can be implemented when the driver assistance system is activated.

[0041] For example, the limitation of steering torque can be applied to the steering wheel 12 of vehicle 1, the EPS motor 14 of the electronic servo steering system 6, or the wheels 16 of vehicle 1. For this purpose, for example, these actuators 4 can be controlled by the controller 2 to induce or inhibit steering wheel movement of the steering wheel 12.

[0042] In particular, the EPS motor 14 can dynamically set the steering position of the wheel 16 within a situation-dependent range when a driving assistance system, such as a lane keeping assist system, is in operation. Here, the limitation on steering behavior can affect or set the maximum steering speed, maximum steering range, or steering angle of the EPS motor 14.

[0043] Controller 2 can set restrictions or dynamically change the steering behavior of vehicle 1.

[0044] Figure 2 The schematic diagram shown illustrates a method 20 according to one embodiment. Method 20 is used to set restrictions on the steering behavior of vehicle 1 and is preferably implemented by controller 2. Method 20 can be configured as a limiter.

[0045] The operation of method 20 is described below. The physical implementation of these functions on the respective controllers 2 should not be limited by this functional block diagram. Therefore, for the purposes of this invention, it is to a certain extent irrelevant which controller the limitation on steering behavior is calculated on, or whether the calculation is assigned to different controllers.

[0046] In the first step 22, the driving status of vehicle 1 is obtained based on the input parameter 21. The driving status of vehicle 1 can be considered as, for example, parking process, slow turning, fast turning, straight driving on a single-lane or multi-lane road, and similar driving conditions.

[0047] To determine the driving status, data about the vehicle's surrounding environment U, the planned trajectory, and / or data from sensors 8 and 10 of vehicle 1 can be received. Next, the driving status of vehicle 1 is determined based on the received data.

[0048] Here, we can consider the situation depending on the quantity and type of input signals or data used: the situation cannot change arbitrarily and rapidly. For example, determined by driving dynamics, vehicle 1 cannot change from straight-ahead to turning within a fraction of a second.

[0049] In a further step 24, condition-related constraints on the steering behavior of vehicle 1, such as steering torque and / or steering gradient, are calculated based on the determined driving conditions. Condition-specific and adapted constraints on the steering torque are calculated.

[0050] Limitations on steering behavior are not limited to reducing or restricting the factors that determine steering. Limitations on steering behavior can also include, for example, widening the limits of steering angle.

[0051] In the next step 26, at least one control command is output to set a calculated condition-related limit on steering behavior 30. This can be achieved, for example, by a software-based and / or hardware-based limiter. The limiter can then be adapted to signals from the driver assistance system 28 to implement the control commands from the controller 2.

[0052] Alternatively, the controller can directly act as a driver assistance system to generate control commands to control the steering behavior of vehicle 1 and drive actuator 4.

[0053] Here, controller 2 can directly influence actuator 4 to achieve limitation. Alternatively or additionally, controller 2 can forward control commands to another controller (not shown) to achieve limitation on steering behavior.

[0054] Method 20, for example in a straight-ahead driving condition, allows only the same amount of steering torque as is typically necessary to maintain straight-ahead driving and to compensate for disturbances such as ruts or crosswinds. When cornering, a higher steering torque or a larger steering torque gradient can be released.

[0055] For example, in cases where the road is highly winding, one could consider using, for instance, the turning radius or dynamic turning direction as a measure of the constraints on turning behavior.

Claims

1. A method (20) for calculating, in relation to conditions, a limit on the steering torque via a controller (2) and / or for calculating, control commands for the steering system of the vehicle (1) via the controller (2), wherein, The method is implemented without driver intervention, wherein, - Receive data about the vehicle's surrounding environment (U), data about the planned trajectory, and data from the sensors (8, 10) of the vehicle (1). - The driving status of the vehicle (1) is determined based on the received data, wherein the determined driving status is classified, and the types of driving status include: parking process, slow turning, fast turning, and straight driving. - Calculate dynamic, condition-dependent constraints on steering behavior based on the type of driving condition being determined, wherein different constraints on steering torque and / or steering torque gradient are calculated for different driving condition types. - Output control commands to set calculated, condition-dependent limits on the steering behavior. In driving conditions classified as straight-ahead, only the amount of steering torque necessary to maintain straight-ahead driving and / or to compensate for disturbances is permitted, and / or Among them, when turning, it can release higher steering torque or a larger steering torque gradient.

2. The method according to claim 1, wherein, In order to obtain the driving conditions, data on driving conditions, the current and planned trajectory of the vehicle (1), the direction of the lane being traveled, the behavior of adjacent traffic participants, identified traffic signs and / or the future lane direction obtained from map data are received.

3. The method according to claim 1 or 2, wherein, The driving conditions and condition-related constraints on the steering behavior are determined using a vehicle model.

4. The method according to any one of claims 1 to 3, wherein, The driving conditions and condition-related limitations on the steering behavior are determined based on historical data, application-specific data, and / or statistical data.

5. The method according to any one of claims 1 to 4, wherein, Existing limitations on steering torque and / or steering gradient can be broadened or restricted by condition-related constraints on the steering behavior.

6. The method according to any one of claims 1 to 5, wherein, In order to impose condition-related restrictions on the steering behavior, lower and upper limit values ​​are calculated and set.

7. The method according to any one of claims 1 to 6, wherein, Condition-related restrictions on the steering behavior are set by output control commands in a manner that limits the steering torque on the steering wheel (12), the EPS motor (14) and / or at least one wheel (16).

8. The method according to any one of claims 1 to 7, wherein, The condition-related limits on the steering behavior are calculated as force boundaries, angle boundaries, and / or position boundaries and set by the output control commands.

9. Controller (2), wherein, The controller (2) is configured to implement the method (20) according to any one of claims 1 to 8.

10. A computer program comprising instructions that, when implemented by a computer or controller (2), arrange for the computer or controller to perform the method according to any one of claims 1 to 8.

11. A machine-readable storage medium on which the computer program of claim 10 is stored.

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