Motor vehicle, vehicle motion control system and method for operating a two-track motor vehicle with a vehicle motion control system

Description

2 / 31 Furthermore, CN110466604A describes a method for differential drive steering for electric vehicles driven by a wheel hub motor. In this method, different drive torques are used at the left and right front wheels to steer the electric vehicle, particularly when the conventional steering system fails. The method is also intended to improve the vehicle's stability in various driving situations, such as when driving through sharp curves or during sudden braking. A control system based on a reference model is described to determine the stability limits and ensure that the vehicle remains within these limits. 10. Furthermore, a method for controlling the driving dynamics of a motor vehicle is known from DE102008001993B4. The aim of the method is to minimize the maximum utilized coefficient of friction at the wheels. The intensity of the interventions of the actuators can be determined for different actuators of the motor vehicle.In particular, a comfort-oriented distribution of interventions is proposed,15 by controlling the interventions so that comfort-impairing actuators are used less intensively. Furthermore, US 11,673,582B1 discloses a vehicle control system that enables the control of a vehicle when its electric power steering system fails.20 The system uses multiple redundant actuators to steer the vehicle's wheels and keep the vehicle on a planned trajectory. When the power steering system is not functioning, correction constraints are calculated in real time to ensure continued vehicle control. The redundant actuators include systems for active rear-axle steering, torque distribution, and differential braking.25 Against this background, one objective of the present invention is to further increase vehicle stability and improve adherence to a target trajectory of a motor vehicle, in particular by improved determination of the actuators to be controlled and / or improved control of the determined actuators. 30 To solve this objective, a method according to claim 1, as well as a vehicle motion control system and a motor vehicle with a vehicle motion control system according to the dependent claims, are proposed. BE2025 / 5081 3 / 31 Further advantageous embodiments of the invention are described in the dependent claims and the description and illustrated in the figures.The proposed solution provides a method for operating a two-track motor vehicle with a vehicle motion control system, wherein the vehicle motion control system determines a target trajectory for the motor vehicle, which the motor vehicle should follow, and acts on actuators of the motor vehicle, which influence the trajectory of the motor vehicle, to ensure compliance with the target trajectory.The vehicle motion control system comprises a reference generator, a control unit, and an assignment unit, wherein the reference generator generates the target trajectory during 10 driving operation of the vehicle, in particular based on a driving direction specified by a vehicle user or an assistance system, the control unit converts the generated target trajectory into target values, in particular target forces and / or target torques and / or target accelerations and / or target yaw rates, which result from the target trajectory at a center of gravity of the vehicle, and wherein the assignment unit determines those actuators of the vehicle that are to be controlled to achieve the target values ​​determined for the center of gravity of the vehicle. In particular, the assignment unit also transmits the values ​​from the actuators Forces, moments and / or wheel steering angles to be implemented and transferred to the specified actuators.Advantageously, the allocation unit also provides information if the target values ​​are not achievable, i.e., if no actuator or combination of actuators can be determined whose control would allow the target values ​​to be achieved. Advantageously, this information is made available for further processing, in particular for adjusting the target trajectory, and further, in particular, for reducing the vehicle speed.25 The task of the vehicle motion control system therefore includes, in particular, controlling the movement of the motor vehicle in such a way that specified characteristics and thus a specified trajectory are implemented. In particular, the vehicle motion control system adapts operating commands for controlling the motor vehicle given by a vehicle user and / or by a30 driver assistance system in order to stabilize the movement of the vehicle resulting from the operating commands and thus to remain as close as possible to the trajectory specified by the operating commands of the vehicle user.The vehicle motion control system advantageously calculates a required route and thus a target trajectory during autonomous driving, 35 BE2025 / 5081 4 / 31 which is then implemented by the vehicle's actuators through corresponding specifications from the vehicle motion control system. The architecture of the vehicle motion control system, which advantageously comprises a reference generator, a control unit and an assignment unit as separate units,5 advantageously forms a basis for a particularly good selection of the actuators to be controlled and for a particularly good regulation for maintaining the target trajectory and thus for stabilizing the vehicle. The reference generator in particular generates the required target trajectory for the vehicle, whereby this target trajectory must be particularly stable from the perspective of vehicle dynamics.The control unit, which may in particular be or comprise a chassis motion control system, advantageously converts the required trajectory into the target values ​​resulting from the trajectory at the vehicle's center of gravity, the center of gravity. These target values ​​include in particular target acceleration values, target forces, target moments, and / or target yaw rates at the center of gravity. Based on the target values, the control variables are then advantageously determined for the vehicle's actuators to maintain the target trajectory, preferably by the allocation unit. The allocation unit then advantageously distributes the control variables, in particular the required forces and / or moments and / or wheel steering angles, to the vehicle's actuators, advantageously returning information if the target values ​​are not determined by a Control of the actuators is feasible.Advantageously, the individual units – reference generator, control unit, and assignment unit – can also be individually adapted. In particular, it is provided that the assignment unit converts the setpoint values, which the control unit 25 has determined for the center of gravity of the vehicle, into control values ​​for the specific actuators. The assignment unit of the vehicle motion control system then advantageously transmits the corresponding control value for each of the specific actuators that are to be controlled to achieve the setpoint trajectory to an actuator control unit assigned to the respective actuator. The actuator control unit 30 assigned to the respective actuator then controls the actuator assigned to this actuator control unit, so that the vehicle advantageously moves according to the setpoint trajectory.Advantageously, the allocation unit receives the required setpoints, in particular the acceleration signals, from the control unit of the vehicle motion control system and sends actuator signals to the actuator control units. The actuator control units then generate, in particular based on a correspondingly stored vehicle model, the setpoints to be achieved for the center of gravity of the motor vehicle. In particular, the allocation unit sends wheel forces to brake and / or drive control units as actuator units, which implement them, and road wheel angles to the steering system control units as actuator units, which implement them. An advantageous design further provides that the vehicle motion control system also includes a parking control unit. This parking control unit is advantageously only active when performing parking maneuvers.In a driving mode of the vehicle, i.e., a mode in which no parking maneuver is performed, the control unit and the assignment unit are advantageously responsible for controlling the movement of the vehicle. The parking control unit is then, in particular, inactive. Advantageously, the reference generator provides the target trajectories both in driving mode and in parking mode. In driving mode, the target trajectory means, in particular, speeds and yaw rates, and in parking mode, in particular, speed and position or heading angle. The reference generator therefore advantageously outputs the target trajectory in these dimensions. 20 Advantageously, the control unit then calculates the target values ​​at the center of gravity (COG; COG: CenterOfGravity) of the motor vehicle based on the values ​​describing the target trajectory and outputs the target values, in particular to the allocation unit.Furthermore, the allocation unit, which can also be called the control allocation unit, advantageously converts these setpoint values ​​into specific "actuator signals", the 25 control variables, such as force, torque and steering angle. For parking maneuver operation, the special parking control unit is advantageously provided, which in particular calculates the longitudinal speed and the steering angles of the motor vehicle directly on the basis of the data of the setpoint trajectory and advantageously uses a separate controller (MPC module) for longitudinal and lateral movement 30, in particular a longitudinal controller and a lateral controller. According to a further advantageous embodiment of the procedure, a vehicle model describing the motor vehicle, in particular a two-track model, describes a relationship between defined target values ​​and assignable actuators.35 BE2025 / 5081 6 / 31 Advantageously, the assignment of the actuators by the assignment unit is therefore based at least partially on this stored vehicle model.A two-track model, also called a complete vehicle model, advantageously provides realistic results for numerous vehicle dynamics problems, such that a suitable allocation of actuators can advantageously be made based on the results of the two-track model. The two-track model is specifically designed as a non-linear two-track model. With the two-track model, in particular the self-steering behavior of the vehicle, driver behavior, vehicle parameters, body movement parameters, tire forces, tire moments, wheel angles and / or control systems for the lateral dynamics of the vehicle can be described. Advantageously, using underlying equations, in particular equations stored in the vehicle model, it is checked for the assignable actuators whether the vehicle dynamics parameters of the respective actuator are maintained in order to achieve the target values ​​using the specific actuators.Advantageously, 15 the specified actuators are controlled in such a way that the vehicle dynamics parameters of each specific actuator are maintained. In this way, vehicle stability is further increased. Should it turn out that a target trajectory would lead to vehicle instability, the reference generator advantageously adjusts the target trajectory accordingly. 20 Another advantageous embodiment of the method provides that, using a cost function, a set of combinations of vehicle actuators is determined, whereby the actuators of each combination can be controlled to achieve the target values. The cost function is advantageously applied to the set of those actuators 25 for which it has already been verified that the vehicle dynamics parameters are maintained when the actuators are controlled. The cost function takes into account Advantageously, deviations from the target values ​​derived from the determined target trajectory are possible.The cost function is then advantageously minimized with respect to the smallest possible deviation from the target values. In particular, however, it is intended that the cost function should yield zero with respect to a deviation from the determined target values. However, especially if this should not be feasible, the deviation from the target values ​​should be kept as small as possible. In this way, it is particularly suitable to determine those actuators or combinations of actuators that should be controlled to implement the target values.35 BE2025 / 5081 7 / 31 In particular, the combination of actuators is calculated in such a way that the cost function, which describes in particular the generated target values ​​as a function of the actuator forces and / or actuator moments and / or actuator states, is advantageously minimized accordingly.5 In particular, another possible embodiment of the procedure provides that a longitudinal direction and a lateral direction for the target trajectory are taken into account when generating the target trajectory. In particular, it has been shown that this allows for further improved control of the vehicle's actuators in order to achieve further improved adherence to the target trajectory. 10 Furthermore, a coordinate system is advantageously used to describe an actual trajectory of the vehicle, wherein the coordinate system advantageously uses a path length, a distance from a direction of travel, and a course angle deviation from the direction of travel, wherein the direction of travel 15 is also advantageously transformed into a trajectory. Advantageously, the application of the coordinate system can provide an improved basis for further improved Control of the actuators is achieved. In particular, the coordinate system is generated using Frenet formulas.The coordinate system is therefore in particular a Frenet coordinate system, in particular with the coordinates path length, distance and course angle deviation. According to an advantageous further development, derivatives of the path length and the distance from the direction of travel, which in particular is provided as a trajectory, are determined. Using the results of the derivatives, a yaw acceleration of the vehicle and a vehicle acceleration in a linear system are advantageously controlled by a model predictive controller (MPC). In particular, the yaw angle is not directly controlled, but only used for the calculations. Advantageously, the first and second derivatives of the path length and the distance from the direction of travel enable state feedback for linearization in the state-space equation. Furthermore, the controller advantageously uses the third derivatives of the path length and the distance from the direction of travel.The third derivatives of path length and distance are used in particular to limit the movement, thereby advantageously making the system more controllable. In particular, the third derivatives, i.e., jerks, can be minimized, so that the movement becomes smoother. The direction of travel specification takes into account in particular the overall movement of the vehicle. In particular, an advantageous design provides that the reference generator comprises a differentiation unit, a limit calculation unit, a model predictive controller, and a feedback linearization unit. Advantageously, the differentiation unit determines derivatives of path length and distance from the direction of travel specification. The limit calculation unit advantageously calculates applicable limits based on a state of the vehicle and predefined limits. 10. Calculating the limit values ​​using the limit value calculation unit has, in particular, two objectives.The first objective is to define the limits that originate from an external source, particularly from the direction of travel or the trajectory. These limits specifically concern the arc length and its first and second derivatives, i.e., the velocity and acceleration along the trajectory, which the direction of travel is advantageously processed as, as well as the deviation from the direction of travel and its first and second derivatives. Additionally, there are limits for the control signals of the model predictive controller, which are advantageously the jerk values. The second objective is to provide realizable limits for the model predictive controller if the model predictive controller encounters problems because the limits are not realizable. Advantageously, using the results of the derivations and the applicable limits, the desired trajectory of the motor vehicle in a linear system is determined by the model predictive controller and the feedback linearization unit.By rearranging the system equations using the feedback linearization unit, it is advantageously possible to calculate some non-measurable values, for example the derivative of the arc length variable, from measured signals. This makes the system equations that the model predictive controller must solve linear. The solution to this linear problem can then be used – with a further rearrangement of the system equations – in combination with the measured signals to provide a solution for the nonlinear system. Advantageously, the model predictive controller calculates the jerk. Jerks are the derivative of acceleration-like signals. For example, for the arc length, the second derivative is the acceleration, and the third derivative corresponds to the jerk. There are two main reasons for using jerk or jerk values. Advantageously, accelerations should be controlled and limited. One advantageous way to do this is to use the jerk as a control signal.Since sudden changes in acceleration, i.e., high jerk values, are unpleasant for vehicle users, it is advantageous that the jerks are calculated and limited by the controller. Furthermore, jerk values ​​are particularly advantageous as control signals because they represent the derivative of the signals to be controlled. Another possible design provides that, in the event of a detected deviation from the target trajectory due to a different direction of movement of the vehicle, a direction correction is executed based on an estimate of the vehicle's slip angle. Advantageously, a vehicle can thus be further stabilized and movement in accordance with the target trajectory can be achieved. Furthermore, the reference generator of the vehicle motion control system advantageously assesses the vehicle's stability during operation using a phase portrait. In particular, the reference generator also includes a vehicle stability assessment unit.The phase portrait is advantageously based on a slip angle and a yaw rate of the vehicle. In particular, the slip angle and yaw rate of the vehicle define the vehicle stability. The phase portrait describes, in particular, the behavior of the vehicle in phase space and takes into account the development of the vehicle's state variables over time. The phase portrait advantageously provides information on vehicle stability, in particular determining the ranges in which the system is stable or unstable. The phase portrait thus advantageously helps to identify, with regard to vehicle dynamics, how the vehicle behaves at different combinations of slip angle and yaw rate, and whether there are stable or unstable states, so that, advantageously, the vehicle can be further improved and kept in a stable state.30 In particular, it is provided that by detecting a wheel steering angle of the steered wheels of the motor vehicle and a detection of a longitudinal vehicle speed of the motor vehicle, a distance from a current driving state position of the motor vehicle is determined in the phase portrait to a region boundary between a stable region in the phase portrait and an unstable region in the phase portrait. In particular, the distance between the current point or the current driving state position in the phase portrait and the boundary of the stable region or the distance between the driving state position, which can also be unstable, and a stable region is determined. 5 Advantageously, the determined distance is incorporated into the control of the vehicle actuators in order to further increase driving stability.Advantageously, maintaining the lateral vehicle speed, and in particular maintaining the lateral vehicle speed and yaw rate, is prioritized when the distance between a currently stable driving state position and the region boundary is less than a specified limit. In particular, the model predictive controller prioritizes maintaining the lateral vehicle speed when the distance between the current stable driving state position and the region boundary is less than a specified limit. Advantageously, this maintains the stability of the vehicle's driving state. Furthermore, this prioritization advantageously improves the perceived driving behavior of the vehicle for the vehicle user.Advantageously, the longitudinal vehicle speed of the motor vehicle is further reduced if the current driving state position lies outside the region boundary 20, and thus, in particular, if the current driving state of the motor vehicle is unstable. Advantageously, this helps to restore the physical stability and controllability of the vehicle. Furthermore, advantageously, a vehicle user remains largely free and undisturbed by perceptible control interventions during the journey, and at the stability limit, the steering intention of the vehicle user 25 is advantageously taken into account by maintaining the lateral speed, even if this is at the expense of reducing the longitudinal speed. A regulator intervention is therefore advantageously provided for, in particular, when the motor vehicle enters an unstable state by leaving the stable range. In this case, there is advantageously no fixed limit for the distance to the region boundary.In particular, an intervention occurs each time the driving condition is unstable, regardless of the distance to the region boundary, in order to restore the stability of the motor vehicle. 35 BE2025 / 5081 11 / 31 According to a further advantageous aspect, the vehicle motion control system includes a parking control unit, wherein, during a parking maneuver operation of the motor vehicle, where the parking maneuver is carried out autonomously using the parking control unit, the desired trajectory of the motor vehicle is decomposed by the reference generator into a longitudinal motion profile and a lateral motion profile.5 During the execution of the parking maneuver, a longitudinal controller advantageously controls a longitudinal motion of the motor vehicle based on the longitudinal motion profile, and a lateral controller advantageously controls a lateral motion of the motor vehicle based on the lateral motion profile.By controlling the lateral and longitudinal movements separately, the structure of the controller can advantageously be kept simple. Advantageously, the longitudinal controller influences wheel forces of the vehicle, which are controlled by a generated longitudinal vehicle speed, by controlling at least one brake actuator and / or at least one drive actuator of the vehicle. The lateral controller advantageously influences a change in the rate of a steering angle of the vehicle by controlling at least one front steering actuator and / or at least one rear steering actuator of the vehicle, particularly in both the forward and reverse directions of travel of the vehicle. 20 The vehicle motion control system further proposed for the solution of the aforementioned problem, which is designed to influence the operation, in particular a driving maneuver, of a motor vehicle, comprises a reference generator, a control unit and an assignment unit.The vehicle motion control system is configured to execute a method 25 developed according to the invention in a motor vehicle, in particular such that the motor vehicle is operated according to a method developed according to the invention. Advantageously, the advantages of the proposed method for operating a motor vehicle described above can thus be realized with the proposed vehicle motion control system. Furthermore, the vehicle motion control system advantageously comprises a parking control unit, in particular a parking control unit 30 developed for controlling the execution of an autonomous parking maneuver.Furthermore, the proposed motor vehicle for solving the aforementioned problem, in particular a passenger car (PKW: passenger vehicle), comprises a plurality of actuators for operating the motor vehicle, in particular at least one drive unit, at least one brake unit and / or at least one steering system; and a vehicle motion control system, in particular a vehicle motion control system designed according to the invention. The motor vehicle is designed to be operated according to a method designed according to the invention. The vehicle motion control system comprises in particular a reference generator, a control unit and an allocation unit. Advantageously, the vehicle motion control system also comprises a parking control unit. The reference generator, the control unit and the allocation unit are interconnected, in particular for interaction, especially for the transmission of data and information.Furthermore, it is specifically provided that the vehicle motion control system is communicatively connected to the actuators of the motor vehicle, in particular to the respective actuator control units of the motor vehicle actuators. In particular, the advantages described in relation to the proposed method for operating a motor vehicle can be realized with the motor vehicle. It is also advantageously provided that the motor vehicle is designed for autonomous driving operation, in particular for autonomous parking, especially using the parking control unit. Further advantageous details, features and design details of the invention are explained in more detail in connection with the exemplary embodiments shown in the figures (hereinafter Fig.: figure). Fig. 1 shows a schematic representation of an exemplary embodiment for a motor vehicle designed according to the invention; Fig. 252 in a block diagram, an embodiment of a vehicle motion control system designed according to the invention with a motor vehicle; Fig. 3 in a highly simplified representation, a movement of a motor vehicle to illustrate a method designed according to the invention; 30 Fig. 4 in a block diagram, an embodiment of a reference generator of a vehicle motion control system designed according to the invention; BE2025 / 5081 13 / 31 Fig. 5 in a block diagram, an embodiment of a parking control unit of a vehicle motion control system designed according to the invention; and Fig. 6 an example of a phase portrait of the embodiment of a method designed according to the invention in a further embodiment. In the various figures, identical parts are generally provided with the same reference numerals and are therefore sometimes only explained in connection with one of the figures. 10 In Fig.Figure 1 shows an advantageous embodiment of a two-track motor vehicle 1 with four wheels 10. The motor vehicle 1 can be, in particular, a passenger car. The motor vehicle 1 comprises a vehicle motion control system 2, which has a reference generator 5, a control unit 6, an assignment unit 7, and a 15 parking control unit 20. The vehicle motion control system 2 is configured to receive current driving states of the motor vehicle 1, which can be detected, in particular, by means of corresponding sensors (not explicitly shown in Figure 1). In particular, the vehicle motion control system 2 is configured to detect steering inputs made by a vehicle user by means of a steering handle 11 of a steer-by-wire steering system 20 of the motor vehicle 1. In addition, the vehicle motion control system 2 is connected to actuators 4 that influence vehicle motion for the transmission of signals.In this embodiment, each wheel 10 of the motor vehicle is assigned a brake actuator 4125, whereby each of the brake actuators 41 can exchange signals with the vehicle motion control system 2. Furthermore, each wheel 10 of the motor vehicle is assigned a drive actuator 42. Each of the drive actuators 42 can, in particular, comprise at least one electric motor. The vehicle motion control system 2 can also exchange signals 30 with the drive actuators 42 in this embodiment. In addition, the motor vehicle 1 in this embodiment comprises a front steering actuator 43v and a rear steering actuator 43h, via which a steering input can be converted into a steering movement of the steerable wheels 10. BE2025 / 5081 14 / 31 When operating the motor vehicle 1, the reference generator 5 is designed to determine a target trajectory that the motor vehicle 1 should follow.The control unit 6 is further configured to convert the generated target trajectory into target values, in particular acceleration values, which result from the target trajectory at a center of gravity 9 of the vehicle 1. The assignment unit 7 is configured to convert the generated target values ​​into 5 control variables and to determine those actuators 4 of the vehicle 1 that are to be controlled to achieve the target values, for example, the steering actuators 43v, 43 and two of the brake actuators 41. For this assignment, a two-track model is implemented in the assignment unit 7 in this embodiment, which describes the connection between the actuators 4 and the target values ​​acting at the vehicle's center of gravity 9. 10 Limitations of the actuator dynamics are described by equations that Assignment unit7 is taken into account when determining the actuators4 to be controlled.The allocation of the actuators 4 for realizing the target values ​​applicable to the vehicle's center of gravity 9 is carried out in this exemplary embodiment using a stored cost function 15, which also takes into account deviations from the determined target values. The cost function is used to select which actuators are used and to what intensity, in particular which brakes are used for braking and to what extent. According to the result thus determined, the actuators 4 to be controlled are defined and the determined actuators 4 are then controlled in the 20 specific manner required to achieve the target values ​​and thus to maintain the target trajectory. The allocation unit7 is also trained to provide information if the specified target values ​​cannot be implemented by a suitable control of actuators4 of the 25 motor vehicle1, i.e. the motor vehicle1 cannot follow the target trajectory.The information provided by the allocation unit 7 can then be used, in particular, to reduce the vehicle speed in order to bring the motor vehicle 1 into a stable state, in which the motor vehicle 1 can follow the detected instructions. With reference to Fig. 2 and Fig. 3, an advantageous embodiment of a method for operating a two-track motor vehicle 1 with a vehicle motion control system 2 is described below, in particular a method for operating a motor vehicle 1 as explained with reference to Fig. 1. Various optional design details are also described. Fig. 2 shows a block diagram of a vehicle motion control system 2 with a motor vehicle 1 to which the vehicle motion control system 2 is assigned. Fig. 3 shows a simplified example of the movement of the motor vehicle 1 according to a direction of travel 30 at the operating motor vehicle 1 is outlined, wherein the motor vehicle 1 is shown in Fig.3 is represented only by a point, which is intended to represent the center of gravity 9 of the motor vehicle 1. In the method for operating a two-track motor vehicle 1 with a vehicle motion control system 2, the vehicle motion control system 2 10 determines a target trajectory 3 for the motor vehicle 1, which the motor vehicle 1 is to follow, in particular based on a detected direction of travel, wherein the direction of travel includes in particular several driving parameters or driving state values, in particular a direction of travel.The determination of the target trajectory is based in particular on recorded vehicle state values, especially current vehicle speeds, further in particular longitudinal and lateral vehicle speeds, current vehicle accelerations, further in particular longitudinal and lateral vehicle accelerations, and / or a current yaw rate and recorded vehicle movement specifications, in particular a recorded steering input, a set wheel steering angle, a recorded accelerator pedal position and / or a recorded brake pedal position. The vehicle movement specifications are made in particular by a corresponding actuation of input devices by a vehicle user and / or by a driver assistance system.25 To ensure that the motor vehicle 1 maintains its movement according to the intended trajectory 3, the vehicle motion control system 2 acts on actuators 4 that influence the movement of the motor vehicle 1, in particular on its steering actuator 43v, 43h, at least its brake actuator 41 and / or at least its drive actuator 42. In addition, it may also be provided that the 30 vehicle motion control system 2 can act on an active spring damping system of the motor vehicle 1 as a further actuator 4. The architecture of the vehicle motion control system 2 in this embodiment provides that the vehicle motion control system 2 comprises, each as a separate 35 BE2025 / 5081 16 / 31 unit, a reference generator 5, a control unit 6, a parking control unit 20 and an assignment unit 7.The reference generator 5, the control unit 6, the parking control unit 20, and the assignment unit 7 are communicatively connected, whereby it is specifically provided that data from the reference generator 5 is transmitted via the control unit 6 to the assignment unit 7 and data from the reference generator 5 is transmitted to the parking control unit 20. In particular, a bidirectional exchange of data between units 5, 6, 7, and 20 is also provided. Specifically, it may also be provided that data is transmitted directly from the assignment unit 7 to the reference generator 5 and / or that the control unit 6 exchanges data with the parking control unit 20. The reference generator 5 of the vehicle motion control system 2 generates the target trajectory 3 according to which the vehicle 1 is to be moved and transmits the result to the control unit 6.The control unit 6 determines target values ​​81 from the generated target trajectory 3, in particular acceleration values, which result from the target trajectory 3 at a center of gravity 9 of the 15 motor vehicle 1. The determined target values ​​81 are transmitted to the assignment unit 7 of the vehicle motion control system 2. The assignment unit 7 converts the target values ​​81 into control values ​​82, in particular target forces, target steering angle, etc. Based on a two-track model for the motor vehicle 1, the assignment unit 7 determines those actuators from the totality of the 20 available actuators 4 of the motor vehicle 1 that are to be controlled so that the motor vehicle 1 behaves according to the target values ​​81 generated from the target trajectory 3, whereby in particular a signal output adapted to the case is also provided as information output. It is intended that achieving the target values81 by controlling the actuators 4 is not possible, especially for physical reasons.25 For the actuators4 determined based on the two-track model, the corresponding control variables82 are sent by the assignment unit7 to an actuator control unit (not explicitly shown in the figures) assigned to the respective actuator4. The respective actuator control unit then controls the actuator4 so that the setpoint variables30 81 are set in the center of gravity9 of the motor vehicle1. For the determination of those actuators4 of the motor vehicle 1 which are to be controlled for achieving target values ​​81, the allocation unit 7 checks, on the basis of stored equations and / or on the basis of a stored system of equations, whether the specified driving dynamics framework conditions of the respective actuator 4 are complied with for 35 BE2025 / 5081 17 / 31 an achievement of the target values ​​81 using one or more of the actuators 4.If it turns out that the vehicle dynamics parameters for an actuator 4 would not be met, then this actuator 4 will not be selected or assigned by the assignment unit 7 for control to achieve the target values ​​81, if other actuators 4 can be controlled appropriately and the vehicle dynamics parameters are met. In particular, only those actuators 4 for which the vehicle dynamics parameters are met will be assigned. If such a selection cannot be made, it is specifically intended that such actuators 4 for which the vehicle dynamics parameters would not be met will only be controlled to a limited extent 10.In this process, the allocation unit 7 further determines, using a cost function, a set of combinations of actuators 4 of the motor vehicle 115 from the actuators identified as assignable using the equations or the system of equations, whereby the actuators 4 of each combination from this set can, in principle, be controlled to achieve the target values ​​81. The cost function takes into account deviations from the determined target values ​​81 and is minimized with respect to the smallest possible number of actuators 4 to be controlled. In this way, it is ultimately determined which of the vehicle actuators 4 are to be controlled to achieve the target values ​​81 as 20. According to an advantageous design variant, it is also provided that when generating the target trajectory 3 by the reference generator 5, a longitudinal direction and a lateral direction for the target trajectory 3 are taken into account.Furthermore, to describe the actual trajectory of the motor vehicle 1, a coordinate system is applied, wherein the coordinate system uses a path length (exemplarily shown in Fig. 3), a distance d from a direction of travel 30, and a course angle deviation θ from the target trajectory 3. In Fig. 3, S_1 is shown as an example of the start of the direction of travel 30. S_a indicates a current target position for the motor vehicle 30, where the distance along the direction of travel 30 from S_1 to S_adie describes the path length. As shown by way of example in Fig. 3, the current position P of the motor vehicle 1 deviates from the direction of travel 30 by the distance d. By parallel displacement of the vector shown, which represents the direction of travel R with the BE2025 / 5081 18 / 31 The vehicle speed V describes the course angle deviation θ in relation to the direction of travel specification 30. By reference generator 5, which in an advantageous design is shown in Fig.As shown in Figure 4, the derivatives of the path length and distance d from the direction of travel 30 are determined in order to then control a yaw acceleration of the vehicle 1 and a vehicle acceleration in a linear system by a model predictive controller 53, whereby the controller 53 calculates in particular the third derivatives of the path length and distance d from the direction of travel 30, especially the jerk, as control signals. In both embodiments shown in Figure 4, the reference generator 5 comprises, in addition to the model predictive controller 53, a differentiation unit 51, a limit calculation unit 52 and a feedback linearization unit 54. The differentiation unit 51 determines the derivatives 511 of the path length and distance d from the direction of travel 30 and forwards this to the limit calculation unit52 and the model predictive controller53.15 Based on a current state of the motor vehicle 1 and predefined limits, the limit calculation unit 52 calculates applicable limits 521 for the results of the derivations 511 and passes these on to the model predictive controller 53. The limit calculation unit 52 calculates in particular specific limits for the model predictive controller 53, in particular predefined limits that must not be exceeded 20, especially speed limits and / or limits that are calculated based on the current vehicle state.Using the input values, in particular the path length, the distance d and the course angle deviation θ, which are in particular the coordinates of a Frenet coordinate system 25, and further using the results of the derivatives 511 as well as the applicable limit values ​​521, the model predictive controller 53 calculates the resulting jerks 531 of the motor vehicle 1 and passes these to the feedback linearization unit 54, to which the input values, in particular the path length, the distance d and the course angle deviation θ, are also transferred. The jerk determined by the model predictive controller 53 is the 30 third derivative of the path length and the distance d from the direction of travel 30 and thus describes in particular a rate of change of acceleration. If this rate of change is large, this leads to a very unpleasant feeling of a Vehicle user. The jerks or corresponding jerk values ​​are therefore advantageously used to limit the accelerations for a vehicle user.35 BE2025 / 5081 19 / 31 The feedback linearization unit 54 ultimately generates the target trajectory in the linear system, in particular reference yaw rate and velocity, and passes this on to the control unit 6. According to an advantageous optional configuration, the reference generator 5 also evaluates vehicle stability during operation of the motor vehicle 1 using a phase portrait, an example of which is shown in Fig. 6. In particular, it is provided here that the reference generator 5 additionally includes a vehicle stability evaluation unit (not explicitly shown in the figures). This phase portrait is based on a slip angle of the motor vehicle 1 (indicated in Fig. 6 on the abscissa axis in rad (rad: radian) 10) and a yaw rate of the motor vehicle 1 (indicated in Fig. 6 on the ordinate axis in rad / s (s: second)).By detecting a steering input, which can be made in particular by a vehicle user via a steering handle 11, the reference generator 5 determines a distance in the phase portrait between a current state position 71, 72 of the vehicle and a region boundary 73 between a stable region, which lies within the region boundary 73 in Fig. 6, and an unstable region, which lies outside the region boundary 73 in Fig. 6. If the distance determined by the reference generator 5 between a currently still stable driving state position 71 is less than a specified limit value, maintaining a lateral vehicle speed and yaw rate of the vehicle 1 is prioritized and the longitudinal vehicle speed 20 of the vehicle 1 is reduced. The reference generator 5 can thus influence the desired trajectory while observing stability criteria. In Fig. 6 The upper and lower limits of the regional border are each acceleration limits.The border right side top and left side bottom of region border 73 characterizing transition to an understeering motor vehicle 125 and the border right side bottom and left side top of region border 73 characterizing transition to an oversteering motor vehicle 1. The phase portrait is therefore advantageously used to determine a stable target trajectory 3 for the motor vehicle 1. In particular, the phase portrait is used to influence the 30 vehicle movement of the motor vehicle 1 so that the motor vehicle returns from an unstable state to a stable state. Advantageously, the distance is therefore calculated, especially for a transition to unstable states of the motor vehicle. However, the robustness of the vehicle control and the vehicle movement is advantageously increased by the fact that the control system avoids the 35 BE2025 / 5081 20 / 31 vehicle state 71 coming too close to the region boundary 73, even if it is still within the region surrounded by the region boundary 73.Therefore, distance calculation is advantageous when the vehicle state position is within the stable range, for example, at vehicle state position 71, in order to maintain vehicle stability. If an unstable vehicle state nevertheless occurs, the vehicle is advantageously returned to a stable vehicle state. If the vehicle 1 is a vehicle designed for autonomous execution of a parking maneuver, the vehicle motion control system 2 additionally includes a parking control unit 20, as also shown by way of example in Fig. 2. This is explained in more detail below 10 with reference to Fig. 5. The parking control unit 20 comprises a longitudinal controller 21, a lateral controller 23, a state transformation unit 22, and a control signal transformation unit 24. The longitudinal controller 21 controls the longitudinal speed 15 of the motor vehicle 1 and outputs a corresponding longitudinal control variable 821.Since this signal can already be controlled in a linear model, no signal transformation is required. For the lateral controller 23, i.e., the lateral control, the trajectory signals must first be transformed by the reference generator 5, in particular linearized. In this embodiment, this is done by the state transformation unit 22. The lateral controller 23 then calculates the control signals, which are first transformed back by the control transformation unit 24 so that they can be used accordingly by the actuators 4 of the vehicle 1. Accordingly, lateral control variables 822.25 are then output. In this embodiment, for the execution of an autonomous parking maneuver, i.e., not for normal driving operation, the target trajectory 3 of the vehicle 1 is decomposed by the reference generator 5 into a longitudinal motion profile and a lateral motion profile.For the execution of this parking maneuver, the longitudinal controller 21 advantageously controls the longitudinal movement of the motor vehicle 1 based on the longitudinal motion profile, and the lateral controller 23, together with the state transformation unit 22 and the control signal transformation unit 24, controls a lateral movement of the motor vehicle 1 based on the lateral motion profile. The longitudinal controller 21 particularly influences wheel forces of the wheels 10 of the motor vehicle 1, which are controlled by a generated longitudinal vehicle speed, by controlling the brake actuators 41 of the motor vehicle 1 and / or by controlling the drive actuators 42 of the motor vehicle 1. The lateral controller 23, on the other hand, particularly influences a change rate of a wheel steering angle of the Motor vehicle 1 by controlling the front steering actuator 43v of the motor vehicle 15 and / or by controlling the rear steering actuator 43h of the motor vehicle 1, in particular in both directions of travel.Finally.

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