WO2019170346A1

WO2019170346A1 - Method for calculating a trajectory limitation, and method for regulating a drive dynamic

Info

Publication number: WO2019170346A1
Application number: PCT/EP2019/052825
Authority: WO
Inventors: Mehrdad SALARI KHANIKI; Stephan Pollmeyer; Eckehard MÜNCH
Original assignee: Zf Friedrichshafen Ag
Priority date: 2018-03-09
Filing date: 2019-02-06
Publication date: 2019-09-12
Also published as: DE102018203617A1

Abstract

The invention relates to a method (V) for calculating a trajectory limitation (1) for at least one driver assistance system (2) of a vehicle (3). Properties (4) of the vehicle (3) are requested which are relevant to the calculation of the trajectory limitation (1). Boundary conditions (5) for the vehicle (3) which are relevant to the calculation of the trajectory limitation (1) are provided by the at least one driver assistance system (2). Current restrictions (7) are requested from at least one actuator (8) of the vehicle (3). On the basis of the properties (4) of the vehicle (3), the boundary conditions (5), and the current restrictions (7) of the at least one actuator (8), a trajectory limitation (1) is calculated, and the trajectory limitation (1) is provided to the at least one driver assistance system (2).

Description

Method for calculating a tractor sector limitation and method for controlling a vehicle dynamics

The present invention relates to a method for calculating a Trajektorien- limitation with the features of claim 1, a method for controlling a driving dynamics with the features of claim 7, a control device for controlling a driving dynamics with the features of claim 8, a computer program product with the features according to claim 9, a computer readable medium having the features of claim 10, and a vehicle having the features of claim 11.

A vehicle has dynamic limits. These limits can be e.g. describe with respect to the lateral dynamics over a maximum representable lateral acceleration or a maximum curvature, with respect to the longitudinal dynamics exist maximum representable longitudinal accelerations and velocities. These limits are determined by various aspects. Examples include tire and roadway properties, but also actuator characteristics (e.g., available drive torques or representable steering angles or torques). In addition, longitudinal and lateral dynamic limits are coupled with each other via the tires. Thus, when cornering at a constant speed, a higher lateral acceleration can be driven stationary than during an accelerated cornering.

In autonomous vehicles or vehicles with driver assistance systems, a desired trajectory is calculated predictively by an algorithm, i. H. planned. A controller converts this setpoint trajectory into setting commands for the actuators of the vehicle. In this case, the current vehicle position is taken into account continuously and intervened in case of deviations between the desired and actual trajectory corrective over the actuators. When planning the target trajectory, the vehicle dynamics limits of the vehicle including all relevant subsystems must be taken into account.

When estimating the driving dynamics limits, a variety of information must be available, eg. As road and tire properties, steering and gear ratios, characteristics of the drive motor, available moments of Lenkaktuaa- sector, vehicle mass and geometry as well as characteristics of the chassis. In addition, information about z. B. legal boundary conditions such as speed limits or overtaking bans, or on comfort constraints, such. As a damping or suspension, are included in this estimate. The description of the driving dynamics limits can in the planning process, for. B. in the form of models or simple (heuristic) characteristics are mapped.

The application of the estimation of the driving dynamics limits in this way is safety-critical. If, for example, the steering ratio is changed during vehicle development and this information is not communicated to the desired trajectory planning algorithm, incorrect driving dynamics limits are determined. The application of the estimation of the driving dynamics limits according to the type just described is also very complicated: the number of vehicle derivatives on a vehicle platform as well as the possible equipment variants (for example with regard to the actuator combinations) are constantly increasing. In addition, an increasing number of driver assistance systems are installed in modern vehicles, in which always the driving dynamics limits must be calculated.

From DE 10 2015 216 236 A1 a method for tracking an autonomously moving vehicle is known. In this case, the maximum possible adhesion for tracking should be exploited. For this purpose, a variable influencing the lateral path guidance is limited and / or regulated as a function of the detected understeer behavior of the vehicle.

Based on the state of the art, the present invention is based on the object of indicating an improved possibility of calculating driving dynamics limits of driver assistance systems and of taking these into account in the desired trajectory planning. In addition, the method should take less time and computing power than methods known from the prior art.

The present invention proposes, starting from the aforementioned object: a method for calculating a trajectory limitation according to claim 1, a method for controlling a driving dynamics according to claim 7, a control device for Control of driving dynamics according to claim 8, a computer program product according to claim 9, a computer readable medium according to claim 10, and a vehicle according to claim 11. Further advantageous embodiments and further developments emerge from the subclaims.

In a method for calculating a trajectory limitation for at least one driver assistance system of a vehicle, properties of the vehicle that are relevant for the calculation of the trajectory limitation are queried. Boundary conditions for the vehicle are provided by the at least one driver assistance system. In this case, only those boundary conditions are provided which are relevant for the calculation of the trajectory limitation. Current actuator limits are queried by at least one actuator of the vehicle. Starting from the properties of the vehicle, from the boundary conditions d and from the current limitations of the at least one actuator, a trajectory limitation is calculated. This trajectory limitation is made available to the at least one driver assistance system. The vehicle may be, for example, a car, commercial vehicle or other land vehicle, but also a watercraft or an aircraft. Preferably, the vehicle is a land vehicle.

A trajectory limitation is to be understood as a driving dynamic limit of the vehicle. This means that the vehicle has predetermined limits with respect to its driving dynamics. The vehicle can therefore move safely and reliably only within these dynamic limits. This trajectory limitation is used by the driver assistance system to determine how it plans the desired trajectory of the vehicle, for. B. to perform an evasive maneuver around an obstacle, a braking maneuver, changing a lane, holding a lane o. Ä automated or autonomous. The desired trajectory is therefore the trajectory on which the vehicle is to move in the further course of the journey. The driver assistance system is designed in such a way that it can carry out a desired trajectory planning of the vehicle and, for example, automatically or autonomously performs a driving maneuver. The trajectory limitation is not calculated by the driver assistance system itself, but rather in a control system. ervorrichtung, which is not part of the driver assistance system, but can be connected or linked with this.

In the method properties of the vehicle are queried. The properties can z. B. static or quasi-static properties of the vehicle, z. B. those properties that do not change or slightly during the ferry service, but are due to the shape of the vehicle. These properties do not change, or only slowly, or negligibly, over time. The static or quasi-static properties are characteristic of each individual vehicle, d. H. Each vehicle may have different static or quasi-static characteristics. These static properties are, for example, wheelbase, maximum and minimum possible steering angle, vehicle length, vehicle width, vehicle height or other static properties. These quasi-static properties are, for example, vehicle mass, tire properties, vehicle length, vehicle width, vehicle height or other quasi-static properties. These properties are stored for example in a memory of the control device and can be queried from this memory.

Furthermore, the boundary conditions for the vehicle are provided by the at least one driver assistance system. That is, the boundary conditions are transmitted from the driver assistance system to the control device. Such boundary conditions may be, for example, driving-dynamic boundary conditions, legal boundary conditions and / or comfort boundary conditions. Driving dynamic boundary conditions are those boundary conditions that may change during the ferry operation of the vehicle. These can be z. B. determined by sensors of the vehicle and forwarded to the driver assistance system. This z. B. forwarded only the driving dynamics boundary conditions that are required for the desired trajectory planning using the driver assistance system. These dynamic driving boundary conditions may include, for example, a longitudinal speed of the vehicle, a longitudinal acceleration of the vehicle, a steering torque of the vehicle, a slip angle of the vehicle, a current steering angle of the vehicle. be zeugs, wheel speeds of the vehicle or other suitable driving dynamic boundary conditions.

Legal boundary conditions are those boundary conditions that can be determined by, for example, a regulation or a law. For example, this may be a predetermined speed limit, the z. B. is detected by means of a street sign recognition. Comfort constraints are those constraints that directly affect the comfort perception of a vehicle user, such as damping or suspension of the vehicle.

For example, in the desired trajectory planning for future cornering, a current longitudinal speed of the vehicle can be provided by the driver assistance system, so that an associated, maximum mobile curvature of the curve can be calculated as trajectory limitation. As another example, in the target trajectory planning for future cornering, a threshold may be provided for the steering torque generated by a steering actuator so that a maximum possible curvature of the curve that a steering system of the vehicle can support can be calculated as the trajectory limitation , This allows the driver of the vehicle at any time be able to override the driver assistance system.

Furthermore, current limitations of at least one actuator of the vehicle are queried. Of course, the current limitations of several actuators of the vehicle can be queried. More specifically, a physical controller of the at least one actuator communicates the current limits to the controller. Alternatively, a computer program product that performs the actuator control and that is present on the controller transmits the current limits of the at least one actuator to another computer program product that is present on the controller and that performs the calculation of the trajectory limitation. Preferably, only the limitations of those actuators are queried, which are of importance for the trajectory limitation. The at least one actuator can, for example, be an actuator of a lever. be of the vehicle, a brake of the vehicle, an engine of the vehicle, a transmission of the vehicle or another vehicle system. This limit may be, for example, an available drive torque, a maximum producible wheel torque, a representable steering angle gradient or another suitable limitation.

Preferably, the interrogated boundary is chosen such that it is decoupled from the at least one actuator. That is, the control device needs to interrogate or know less static or quasi-static properties of the vehicle or characteristics of the at least one actuator. If, for example, a maximum torque of the motor is interrogated as limit, a shift strategy and a gear ratio must also be known in order to be able to calculate a maximum longitudinal acceleration as a trajectory limitation. If, on the other hand, a wheel torque which can be generated maximally by the motor is interrogated as the limit, this additional information need no longer be known.

This reduces the susceptibility to errors.

Based on the properties of the vehicle, the boundary conditions for the vehicle and the current limitations of the at least one actuator, a trajectory limitation is calculated. In this case, the already described query of the properties, the boundary conditions and the current limitations of the actuators can take place simultaneously or successively. The trajectory limitation is forwarded to the driver assistance system. This calculation takes place in the control device, ie not in the driver assistance system. The driver assistance system merely receives the result of determining the trajectory limitation.

In this case, it is preferable to decouple the trajectory limitation from the vehicle systems. That is, the driver assistance system must be known less static or quasi-static properties of the vehicle or limitations of the at least one actuator. If, for example, a maximum wheel torque or a maximum steering angle is determined as the trajectory limitation and transmitted to the driver assistance system, the driver assistance system must provide further information, such as, for example, the driver assistance system. B. vehicle mass and wheelbase present to a determine maximum possible longitudinal acceleration or a maximum mobile curve curvature for the desired trajectory planning. If, on the other hand, a maximum possible longitudinal acceleration or a maximum mobile curve curvature is calculated directly as trajectory limitation, this further information is no longer necessary for the driver assistance system.

The method just described runs continuously during the ferry operation of the vehicle, for example. This means that when traveling with the vehicle, if the at least one driver assistance system is active, the method is used continuously in order to provide the trajectory limitation for its planning of the desired trajectories to the at least one driver assistance system. It is alternatively possible that the method described does not run continuously. For example, a calculation of the trajectory limitation can only be carried out if the boundary conditions, for example the driving-dynamic boundary conditions, or the boundaries of the at least one actuator change, e.g. when an electric motor of the vehicle or a brake of the vehicle is overheated, or if the at least one driver assistance system is exposed to a new situation.

An advantage of the method just described is that the driver assistance system itself does not have to calculate any trajectory limitation for its desired trajectory planning. As a result, the check as to whether a desired trajectory is mobile is very efficient. If the procedure were designed in such a way that the driver assistance system hands over a desired trajectory for the calculation of the trajectory limitation for checking, the result of this calculation could be negative (ie "trajectory not mobile"). The desired trajectory can z. B. as a polynomial depending on the time or in the form of multiple point coordinates. The driver assistance system would have to correct the target trajectory after this negative feedback and give it again to the test for the calculation of trajectory limitation. This would be repeated until the test is positive. This iterative approach to finding a drivable target trajectory is not necessary in the proposed approach. It is also advantageous that the development and application costs are reduced in comparison to conventional methods, since the trajectory limitation is calculated only at one point. As a result, a necessary computing power and thus also an energy requirement based on the total vehicle level are reduced. This advantage is especially evident when the vehicle has several driver assistance systems that operate in parallel. Each of these driver assistance systems receives its trajectory limitation from the same control device. That is, each driver assistance system outsources its computing power to the controller. This can z. B. redundant arithmetic operations are avoided. In addition, the calculation of the trajectory limitation need only be adapted in the control device to different sensor sets, different vehicle configurations and different static vehicle characteristics, and not in each driver assistance system of the vehicle. This means that the adaptation of all driver assistance systems of a vehicle to this very vehicle during production is considerably simplified.

According to one embodiment, the trajectory limitation is described as at least one envelope surface in a state space of the vehicle. This at least one envelope surface is described by means of a mathematical illustration. At least one parameter of the mathematical mapping is calculated, this parameter being made available to the at least one driver assistance system (2). This envelope surface describes a border region within which the vehicle can move in the driving state space. As a result, links between longitudinal dynamic and lateral dynamic limits of the vehicle can be mapped. The envelope surface here denotes the n-1-dimensional boundary of an n-dimensional volume. The envelope surface therefore does not have to be two-dimensional. Furthermore, the envelope surface may be formed as an intersection of a plurality of auxiliary envelope surfaces.

The state space is composed, for example, of the various driving states that the vehicle can assume. The driving condition can z. B. about a longitudinal velocity, a longitudinal acceleration, a yaw rate, a yaw acceleration, a slip angle, a Schwimmwinkelgeschwindigkeit, or similar. loading be written. As an alternative to the yaw rate and yaw acceleration (time derivative of the yaw rate), a curve curvature and a temporal change of the curve curvature can describe the driving state.

In this case, the envelope surface has a predetermined complex geometry which can change as a function of the actuator limitations or other variables which are taken into account in the calculation of the trajectory limitation. Preferably, the envelope surface can be described by means of a mathematical formula which at least approximately maps the geometry of this envelope surface. The parameters included in this mathematical description must be calculated in dependence on the actuator limits or other quantities considered in the calculation of the trajectory limitations. This mathematical mapping of the envelope surface is preferably stored in the control device. In addition, the mathematical mapping of the envelope is known to any relevant driver assistance system. Advantageously, then only the current values of the parameters must be transmitted to transmit the trajectory limitations.

For example, the envelope surface may be described as a linear inequality system. As long as the envelope surface is convex, it can be approximated by a plurality of linear inequalities. The linear inequality system can have the following form:

A x <b

With A = coefficients matrix

x = vector

b = vector

Such inequalities can be considered as linear inequality constraints by known optimization techniques, e.g. Example by means of linear or quadratic optimization methods, by means of SQP (Quasi-Newton method) or by means of interior-point method. In order to calculate the trajectory limitation, the parameters A and b of the inequality system in the control device are calculated and forwarded to the driver assistance system. This evaluates the inequality system at a required operating point of the vehicle during the ferry operation. The result of this evaluation is included in the target trajectory planning. With the help of the inequality, it is thus possible to check directly in the desired trajectory planning whether a driving condition is mobile. A re-calculation and transmission to the driver assistance system need only be done when changing sizes that are not included in the dimensions of the shell, eg. B. a vehicle mass or a coefficient of friction of a road.

Alternatively, the envelope may be described, for example, by means of a tree-like subdivision approach, e.g. Example by means of octree, K-D tree or bounding volume hierarchy. Again, alternatively, the envelope may, for example by means of a Polynomzugs, z. B. by means of a spline surface described.

It is additionally possible that the envelope surface not only describes the trajectory limitations as a function of the driving state variables, but also adds additional dimensions to the description. These dimensions can be, for example, variables such as wheel torques of a drive train, a vehicle mass or a coefficient of friction. In general, these quantities can be the quantities that are taken into account when calculating the trajectory limitations. The relationships of these quantities with the calculation of the trajectory limitation and the effects of these quantities on the trajectory limitation are known. If the description of the envelope surface is extended in such a way, the driver assistance system can, with knowledge of an available wheel torque (corresponding to a limit of the drive train), the coefficient of friction or the vehicle mass, calculate the trajectory limitation without changing the relevant variables in the control device a new envelope has to be calculated.

This further reduces the computational effort.

According to a further embodiment, a reference variable is queried as the current limit of the at least one actuator, which is used directly in the determination of the trajectory. Torien limitation is included. As a result, the previously described decoupling of the interrogated boundary from the at least one actuator is realized. In order to be able to calculate the trajectory limitation, a variable for the current limitation of the at least one actuator is selected such that no further properties of the corresponding actuator need to be known. For example, a maximum producible wheel torque can be queried as a limit.

According to a further embodiment, the trajectory limitation is linked to an additional signal for assignment, so that an assignment of the trajectory limitation to the at least one driver assistance system is made possible. This assignment signal is advantageous when a number of driver assistance systems of the vehicle access the method for calculating the trajectory limitation. The driver assistance systems are active at the same time, for example a Lane Keeping Assist and an Emergency Brake Assist.

For example, a coordination point can be connected between the driver assistance systems and the control device. This coordination point coordinates the queries regarding the trajectory limitation of the individual driver assistance systems and arranges them in an order in which the requests are processed. Alternatively, it can be provided that several instances of the determination of the trajectory limitation are provided which calculate in parallel the trajectory limits for the various driver assistance systems.

Each calculated trajectory limitation is assigned a specific assignment signal, so that it is clearly possible to determine which trajectory limitation is intended for which driver assistance system. For example, each boundary condition provided by one of the driver assistance systems may be assigned a numeric code as an assignment signal. This numerical code is sent back to the driver assistance system by the control device together with the calculated trajectory limitation. This allows an unambiguous assignment of the trajectory limits to the given boundary conditions. Advantageously, the same controller may perform the method of calculating trajectory limitation for multiple driver assistance systems. This reduces the necessary computing power and thus the energy consumption.

In a method for controlling a driving dynamics for a vehicle, the at least one driver assistance system is provided with a trajectory limitation by means of the method which has already been described in the previous description. The desired trajectory is planned by the at least one driver assistance system on the basis of this trajectory limitation, based on an actual position of the vehicle and on the basis of an environmental model of the vehicle. The environment model is based on the sensor data of at least one environmental sensor system of the vehicle. Starting from the actual position and the desired trajectory, manipulated variables for the at least one actuator of the vehicle are calculated. Based on the manipulated variables, the at least one actuator is controlled in such a way that the vehicle moves along the desired trajectory.

The actual position of the vehicle is determined by means of a system for position determination, for example by means of GPS or by means of another suitable system for position or coordinate determination.

The environment model of the vehicle depicts the environment of the vehicle. In this case, sensor data of at least one environment sensor system are used to create the environment model. The at least one environment sensor system can be z. Example, a radar sensor system, a lidar sensor system, a camera system, an infrared sensor system, another imaging sensor system, an acoustic sensor system o. Ä. Be. Of course, the vehicle may have more than one environment sensor system, for example, a combination of the aforementioned sensor systems. These can also be linked with map data. Accordingly, in the environment model, it is shown how the road course is on the driving route of the vehicle, which obstacles are present in the surroundings of the vehicle, which slope or which slope exists, which weather conditions prevail, etc. That means that the environment model contains all the information, which requires the at least one driver assistance system to plan the desired trajectory. The environment model can be present in a central control unit ((domain) ECU) and transmitted to the at least one driver assistance system.

The at least one driver assistance system uses the environmental model, the trajectory limitation and the actual position to plan the target trajectory. For example, the driver assistance system may plan an evasive maneuver around an obstacle, a lane entry, a lane stop, an overtaking maneuver, or the like

The desired trajectory and the actual position are used by the control device to calculate manipulated variables for the at least one actuator of the vehicle. The manipulated variables can be calculated, for example, by a driving dynamics controller of the control device. The manipulated variables are selected such that they are located within the boundaries of the at least one actuator. These manipulated variables are used to control the at least one actuator in such a way that the vehicle moves along the desired trajectory. In other words, setting commands are forwarded to the at least one actuator. As a result, the vehicle moves automatically or autonomously along the planned target trajectory. If more than one driver assistance system is active, so that a plurality of desired trajectories are present, z. Example, be determined by means of a predetermined Arbitirier method, which is the planned target trajectories to be driven by the vehicle. It is important that all of these active driver assistance systems receive their respective trajectory limitations by the method already described.

For each driver assistance system, therefore, a specific trajectory limitation can be calculated.

The method just described runs continuously as long as the driver assistance system is activated. This means that during the ferry operation of the vehicle, when the at least one driver assistance system is active, the control variables are permanently determined in order to control the at least one actuator of the vehicle and this is permanently controlled so that the vehicle moves along the target T trajectory.

A control device for controlling a driving dynamics for a vehicle has an interface, by means of which the control device can be connected to the at least one driver assistance system. The control device has a further interface, by means of which the control device can be connected to the at least one actuator of the vehicle. The control device has means to perform the method for controlling the driving dynamics, which has already been described.

The control device can therefore be connected to the at least one driver assistance system by means of the interface. Each interface is set up so that a data and / or signal exchange can take place via this interface. The connection between the control device and the at least one driver assistance system can be wired or wireless. The control device has the further interface, by means of which the control device can be connected to the at least one actuator of the vehicle, more precisely to the control device of this actuator. This connection can also be wired or wireless. Of course, the control device may be connected to more than one driver assistance system and to more than one actuator.

Alternatively, both the at least one driver assistance system and the control device of the at least one actuator may be present as a respective computer program product and be present on the control device. In this case, there is a virtual interface so that these computer program products can communicate with that computer program product which carries out the steps of the method which has already been described in the previous description and which is also present on the control device.

Thus, the control device comprises means adapted to carry out the steps of the method already described in the previous description. For example, the control device is formed as a (domain) ECU. In front- Preferably, the control device comprises a computer program product for carrying out the method. The control device comprises z. B. a driving dynamics controller. The control device is part of a vehicle control or a separate control device, for example.

The computer program product includes instructions that cause the controller described previously in the description to perform the method steps of the method already described in the previous description.

A computer-readable medium includes the computer program product already described in the previous description. This computer program product serves to carry out the method steps of the method which has already been described in the previous description. The term "computer-readable medium" is understood to mean, for example, hard disks and / or servers and / or memory sticks and / or flash memories and / or DVDs and / or bluerays and / or CDs and / or a downloadable data stream.

A vehicle has at least one driver assistance system, at least one actuator and at least one environment sensor system. The at least one driver assistance system is connected to the at least one environment sensor system, so that a data and signal exchange can take place. The vehicle has a control device which has already been described. The control device is connected to the at least one driver assistance system by means of the interface and to the at least one actuator by means of the further interface. By means of the control device, the vehicle is capable of automatically or autonomously driving along the setpoint trajectory which was predetermined by the at least one driver assistance system.

Various embodiments and details of the invention will be described in more detail with reference to the figures explained below. Show it: 1 is a schematic representation of a method for controlling a driving dynamics of a vehicle according to an embodiment,

2 is a schematic representation of a method for controlling a driving dynamics of a vehicle according to a further embodiment,

Fig. 3 is a schematic representation of a vehicle according to an embodiment.

1 shows a schematic representation of a method U for regulating a driving dynamics of a vehicle 3 according to an exemplary embodiment. The vehicle 3 shown here has a driver assistance system 2 and a plurality of actuators 8, which are shown here for reasons of clarity as a block. The actuators 8 are, for example, actuators 8 of the steering, the drive and the brakes. Furthermore, the vehicle 3 has a control device 13. This control device 13 has a vehicle dynamics controller 15, a memory 14, and a module that executes a method V for determining a trajectory limitation 1. In addition, the control device 13 has two interfaces 11, by means of which it is connected to the driver assistance system 2 and to the actuators 8.

In the method U for controlling the driving dynamics, a desired trajectory 6 along which the vehicle 3 is to move is determined by the driver assistance system 2. In order to calculate the desired trajectory 6, the driver assistance system 2 is provided with a trajectory limitation 1.

To determine the trajectory limitation 1, the properties 4 of the vehicle 3 are first retrieved from the memory 14 and transferred to the method V. These properties 4 are, for example, a vehicle mass or a wheelbase. In addition, boundary conditions 5 for the vehicle 3, which are relevant for the calculation of the trajectory limitation 1, are transmitted by the driver assistance system 2 and transmitted to the method V. These boundary conditions 5 are, for example, a currently prevailing longitudinal speed and a currently prevailing longitudinal acceleration of the vehicle 3. In addition, a request 16 placed after the current limits 7 of the actuators 8 to the actuators 8. Subsequently, these limits 7 are transferred to the method V. A limitation 7 can z. B. be a maximum producible wheel torque.

With this available information, namely the properties 4 of the vehicle 3, the boundary conditions 5 and the current limitations 7 of the actuators 8, the trajectory limitation 1 is calculated by means of the method V. It is advantageous if the queried boundaries 7 are such that they are decoupled from the vehicle systems. This means that the boundaries 7 can be incorporated directly into the calculation of the trajectory limitation 1, without it being necessary to know further properties of the respective actuator 8. A costly conversion is eliminated thereby.

The trajectory limitation 1 is subsequently output to the driver assistance system 2. It is advantageous if the trajectory limitation 1 is represented as an envelope surface. This envelope surface can be imaged by means of a mathematical description. The mathematical description of the envelope surface is known to the driver assistance system 2, so that only the calculated parameters of the envelope surface have to be output by the method V to the driver assistance system 2. As a result, the trajectory limitation 1 is forwarded.

The driver assistance system 2 uses the trajectory limitation 1, an actual position 9 of the vehicle 3 and an environment model 17 of the vehicle 3 in order to plan the desired trajectory 6 for the vehicle 3. The environment model 17 is based on sensor data of the environment sensor systems 10. These are, for example, data of the radar sensors, the lidar sensors, camera data, but also navigation and map data. The environment model 17 describes the environment in which the vehicle 3 is moving. The driver assistance system 2 is provided with the environment model 17 by the environment sensor systems 10. The target trajectory 6 does not have to be planned iteratively, but is planned directly in one step so that it can be moved with the vehicle 3. This is possible because not only a desired trajectory 6 is planned, in which subsequently it has to be checked whether this is compatible with the given properties 4 of the vehicle 3, with the current limits. gen 7 of the actuators 8, and with the boundary conditions 5 is mobile at all.

If this is not mobile, namely, a new target trajectory 6 must be planned, which in turn must be checked. By making available the trajectory limitation 1, the driver assistance system 2 has all the necessary information in the planning of the desired trajectory.

The target trajectory 6 and the actual position 9 are forwarded by the driver assistance system 2 to the control device 13, more precisely to the driving dynamics controller 15 of the control device 13. Based on the desired trajectory 6 and the actual position 9, this calculates the manipulated variables 12 for the actuators 8. The manipulated variables 12 are forwarded to the actuators 8. In other words, the actuators 8 are controlled by means of the manipulated variables 12. The actuators 8 are adjusted starting from the manipulated variables 12 such that the vehicle 3 is enabled to travel along the desired trajectory 6.

For example, the target trajectory 6 may be the trajectory along which the vehicle 3 is to move automatically through a curve in the future. For this purpose, the boundary condition 5, which flows into the method V, may be the actual longitudinal speed of the vehicle 3. The boundaries 7 of the actuators 8 may be, for example, a maximum einschlagbarer steering angle and a maximum producible wheel torque. The properties 4 in this case can be, for example, the wheelbase and the vehicle mass. The trajectory limitation 1 can therefore be a maximum mobile curvature of the curve.

The method U shown here for controlling the vehicle dynamics is designed such that it runs continuously during the ferry operation of the vehicle 3. This means that the method U is used during the entire journey when the driver assistance system 2 is active.

An advantage of the method U for controlling the driving dynamics and the control device 13 shown here is that the calculation of the trajectory limitation 1 is carried out centrally. As a result, the computational effort of the driver assistance system 2 is reduced. Furthermore, the application effort is reduced because the driver 2 does not have to know all the properties 4 of the vehicle 3 and all the limitations 7 of the actuators 8 in order to plan the desired trajectory 6 because they vary from vehicle to vehicle. Therefore, the same driver assistance system 2 can be transferred to different vehicles 3 with reduced application effort, since this does not have to be adapted to the vehicle configuration (properties 4, sensors, actuators 8) of the individual vehicle 3. Only the calculation of the trajectory limitation is adapted to the above-mentioned vehicle configuration.

FIG. 2 shows a schematic representation of a method U for regulating a driving dynamics of a vehicle 3 according to a further exemplary embodiment. The method U is the same as shown in FIG. 1, only three driver assistance systems 2 are now connected to the control device 13 via the interface 11. For a better overview, therefore, the arrows representing the data transmission between the control device 13 and the respective driver assistance system 2 are shown in simplified form as a double arrow.

Each driver assistance system 2 forwards the current boundary conditions 5 to the control device in the method V for determining the trajectory limitation 1. Each driver assistance system 2 receives from the control device 13 from the method V for determining the trajectory limitation 1 its specific trajectory limitation 1. This is calculated individually by means of the method V for each driver assistance system 2. That is, each driver assistance system 2 queries its specific trajectory limitation 1. This can, for example, take place parallel to one another or in an ordered sequence. Each trajectory limitation 1 can be provided with an assignment signal that allows the trajectory limitation 1 to be assigned to the driver assistance system 2 for which it is intended. This can z. B. in the transmission of the (driving dynamic) boundary conditions 5 this already be provided with an assignment signal, so that the trajectory limitation 1, which is among other things calculated from these driving dynamics boundary conditions 5, the same assignment signal. The control device 13, as already shown in FIG. 1, is connected to the actuators 8 of the vehicle 3 via the interface 11. For the method V for determining the trajectory limitation 1 from the actuators 8, the control device 13 queries the current limits 7 of these by means of the query 16. In this case, all limitations 7 are queried, which are necessary for the determination of the trajectory limits 1 of the three driver assistance systems 2.

Each driver assistance system 2 plans, starting from the trajectory limitation 1, from the actual position 9 of the vehicle 3 and from the environment model 17 of the environment sensor system 10, its nominal trajectory 6.

Each driver assistance system 2 transmits its planned setpoint trajectory 6 and the actual position 9 of the vehicle 3 to the vehicle dynamics controller 15 of the control device 13. If these setpoint trajectories 6 coincide, the vehicle dynamics controller 15 of the control device 13 computes the manipulated variables 12 for the vehicle Actuators 8 of the vehicle 3. By means of the manipulated variables 8, the actuators 8 are controlled such that the vehicle 3 runs along the desired trajectory 6. However, if the target trajectories 6 of the individual driver assistance systems 2 deviate from each other, z. B. be determined by means of an Arbitirer method, which target trajectory 6 is to be driven in the future.

3 shows a schematic illustration of a vehicle 3 according to an exemplary embodiment. A highly simplified representation of the vehicle 3 is shown, which has a control device 13, as already shown in FIG. 1 or FIG. 2. The control device 13 carries out the method U for regulating the driving dynamics of the vehicle 3 as well as the method V for determining the trajectory limitation 1.

The control device 13 is connected via its interfaces 1 1 both with a driver assistance system 2 and with an actuator 8, so that a data exchange is possible. The actuator 8 shown here serves to set a steering angle at the wheels of the front axle of the vehicle 3. Furthermore, the vehicle 3 has an environment sensor system 10. This is compatible with the driver assistance system. tem 2 connected, so that a data exchange can take place. Based on the sensor data of the environment sensors, the environment sensor system 10 generates an environment model 17 of the vehicle environment and forwards it to the driver assistance system 2, as explained in FIG. 1.

The vehicle 3 moves along the road in the direction indicated by the arrow. In this drive, the driver assistance system 2 is active and automatically performs driving maneuvers of the vehicle 2. For example, the driver assistance system 2 may be designed such that it can automatically perform a lane change of the vehicle 3. For this purpose, the driver assistance system 2 plans, starting from the trajectory limitation 1, from the environment model 17 and from the actual position 9, the target trajectory 6 and forwards them together with the actual position 9 of the vehicle 3 to the control device 13. The control device calculates the manipulated variables 12 of the actuators 8. The actuators 8 are controlled by means of the manipulated variables 12 in such a way that the vehicle 3 moves along the desired trajectory 6. For this purpose, the steering angle at the wheels of the vehicle 3 are adjusted by means of the actuators 8 such that the vehicle 3 can change a lane.

The examples shown here are only examples. For example, the driver assistance system can be designed such that it enables the vehicle to drive completely autonomously or partially autonomously. Of course, the vehicle may have more than three driver assistance systems, wherein each driver assistance system can receive its trajectory limitation by means of the method for determining the trajectory limitation.

reference numeral

1 trajectory limitation

2 driver assistance system

3 vehicle

4 characteristics of the vehicle

5 boundary conditions of the vehicle

6 target trajectory

7 current limitations of the actuators

8 actuator

9 Actual position of the vehicle

10 environment sensor system

1 1 interface

12 manipulated variables

13 control device

14 memory

15 driving dynamics controller

16 request

17 environment model

U procedure

V procedure

Claims

claims

A method (V) for calculating a trajectory limitation (1) for at least one driver assistance system (2) of a vehicle (3), wherein

- Querying properties (4) of the vehicle (3) which are relevant for the calculation of the trajectory limitation (1),

Boundary conditions (5) for the vehicle (3) are provided by the at least one driver assistance system (2), which are relevant for the calculation of the trajectory limitation (1),

current limits (7) of at least one actuator (8) of the vehicle (3) are queried,

a trajectory limitation (1) is calculated starting from the properties (4) of the vehicle (3), from the boundary conditions (5) of the vehicle (3) and from the current limitations (7) of the at least one actuator (8),

- This trajectory limitation (1) the at least one driver assistance system (2) is provided.

2. Method (V) according to claim 1, characterized in that the trajectory limitation (1) is described as at least one envelope surface in a state space of the vehicle (3), this at least one envelope surface being described by means of a mathematical mapping, wherein at least a parameter of the mathematical mapping is calculated, this parameter being made available to the at least one driver assistance system (2).

3. Method (V) according to claim 2, characterized in that at least one driving state is a longitudinal speed, a longitudinal acceleration, a yaw rate, a yaw acceleration, a slip angle, a slip angle velocity, a curve curvature or a temporal change of the curve curvature.

4. Method (V) according to claim 2 or 3, characterized in that the envelope surface is additionally added at least one further dimension, which is taken into account in the calculation of the trajectory limitation (1).

5. The method (V) according to any one of the preceding claims, characterized in that as a current limit (7) of the at least one actuator (8) a reference value is queried, which flows directly into the determination of trajectory limitation (1).

6. Method (V) according to one of the preceding claims, characterized in that the trajectory limitation (1) is linked to an additional signal for assignment, so that an assignment of the trajectory limitation (1) to the at least one driver assistance system (2 ) is possible.

7. A method (U) for controlling a driving dynamics for a vehicle (3), characterized in that

- the at least one driver assistance system (2) is provided with a trajectory limitation (1) by means of the method (V) according to one of the preceding claims,

- The desired trajectory (6) of the at least one driver assistance system (2) on the basis of this trajectory limitation (1), starting from an actual position (9) of the vehicle (3) and starting from an environmental model (17) of the vehicle (3), wherein the environmental model (17) is based on the sensor data of at least one environment sensor system (10) of the vehicle (3),

- Starting from the actual position (9) and the desired trajectory (6) manipulated variables (12) for the at least one actuator (8) of the vehicle (3) are calculated,

- Based on the manipulated variables (12), the at least one actuator (8) is controlled such that the vehicle (3) moves along the desired trajectory (6).

8. Control device (13) for controlling a driving dynamics for a vehicle (3), comprising an interface (1 1), by means of which the control device (13) with the at least one driver assistance system (2) is connectable, a further interface (15) by means in which the control device (13) can be connected to the at least one actuator (8) of the vehicle (3), characterized in that the control device (13) has means for carrying out the method (U) according to claim 7.

A computer program product comprising instructions for causing the control device (13) according to claim 8 to carry out the method steps of the method (U) according to claim 7.

A computer readable medium, characterized in that the computer readable medium comprises the computer program product of claim 9.

11. Vehicle (3), comprising at least one driver assistance system (2), at least one actuator (8), at least one environment sensor system (10), wherein the at least one driver assistance system (2) connected to the at least one environment sensor system (10) characterized in that the vehicle (3) comprises a control device (13) according to claim 8, wherein the control device (13) is associated with the at least one driver assistance system (2) and with the at least one actuator (8).