Data structure for controlling a chassis system of a vehicle with at least one actuator

Abstract

A data structure is described for actuating a chassis system of a vehicle having at least one actuator which can be actuated to carry out wheel-selective and / or axle-selective interventions, the data structure comprising at least one of the following substructures: - a first substructure for setting a force direction of the actuator, - a second substructure for distributing a rolling moment by means of the actuator, - a third substructure for providing the rolling moment, - a fourth substructure for changing the vehicle height by means of the at least one actuator, - a fifth substructure for changing the rigidity of the actuator, and - a sixth substructure for prioritizing driving dynamics requirements. The invention further relates to a corresponding method and to a corresponding device.

Description

[0001] Description

[0002] Data structure for controlling a vehicle's chassis system with at least one actuator

[0003] The present invention relates to a data structure for controlling a chassis system of a vehicle.

[0004] State of the art

[0005] Modern suspension systems are an integral part of a vehicle, guaranteeing driving safety and comfort. Independent wheel suspensions are state of the art in passenger cars, where spring-damper systems – preferably consisting of a cylindrical or barrel spring and a hydraulic damper – decouple the unsprung mass (wheel) from the sprung mass (chassis). The spring ensures the wheel maintains contact with the road and allows for wheel deflection, for example, when encountering uneven surfaces. The damper dampens the resulting vibrations and provides progressive damping with increasing velocity. Optimal tire-road contact (aiming for safety and driving dynamics through high spring stiffness and constant damping) and occupant comfort (aiming for decoupling road vibrations through low spring stiffness) are inherently conflicting design considerations.

[0006] To resolve this design conflict, modern vehicles are increasingly incorporating (semi-)active suspension components alongside classic passive suspension components with fixed parameters for spring stiffness and damping constant. These are primarily systems that dynamically adjust the damping characteristics or the contact force (active suspension systems and semi-active dampers) and actuators for adjusting roll stiffness (active roll stabilizer). Separate control units and, in particular, control logics are usually used to manage these components, often focusing solely on the vehicle's vertical dynamics.

[0007] The document DE 10 2012 223 984 A1 discloses a method for operating a motor vehicle, wherein a controllable, active spring-damper system of the motor vehicle is controlled to influence wheel contact forces (individually) by changing a damper characteristic when a highly dynamic driving maneuver, in particular an evasive lane change, is detected, and / or wherein a controllable roll stabilization system of the motor vehicle is controlled to influence the self-steering behavior of the motor vehicle (axle-wise) by imposing a roll moment when a curve is detected.

[0008] The publication DE 10 2016 217 101 A1 discloses a method for controlling actuators in a vertically active or semi-active chassis of a two-track, two-axle motor vehicle in such a way that, taking into account a desired driving maneuver, an available friction potential between the wheels of the vehicle and the road surface can be largely utilized by influencing the vertically acting wheel contact forces between the wheels and the road surface.

[0009] The publication EP 2 832 599 A1 discloses a control system for wheel- and axle-specific semi-active and active suspension systems.

[0010] Disclosure of the invention

[0011] Advantages of the invention

[0012] A data structure for controlling a vehicle's chassis system with at least one actuator for performing wheel-selective and / or axle-selective interventions, comprising the features of the independent patent claim, is disclosed. The data structure includes at least one of the substructures described in more detail below.

[0013] A first substructure serves to set the direction of force of the actuator. A second substructure serves to distribute a roll moment by means of the actuator.

[0014] A third substructure serves to provide the roll moment.

[0015] A fourth substructure serves to change the vehicle's height using at least one actuator.

[0016] A fifth substructure serves to change the stiffness of the actuator, and a sixth substructure serves to prioritize driving dynamics requirements.

[0017] The data structure enables a significantly more efficient interaction between vertical dynamics control and vehicle dynamics control compared to the prior art. The data structure described in the invention allows for the simultaneous optimization of both vehicle dynamics and vehicle safety. Furthermore, it significantly reduces the coordination effort required due to mutual dependencies between vertical dynamics control and vehicle dynamics control, thereby saving development resources.

[0018] Further advantageous embodiments of the present invention are the subject of the dependent claims.

[0019] Advantageously, the data structure includes at least one of the following substructures: a seventh substructure for distributing a pitching moment by means of the actuator; an eighth substructure for providing a pitching moment; a ninth substructure for individually requesting a subordinate ground hook control.

[0020] This is advantageous because it allows a defined pitching moment to be set and the ground hook control to influence the wheel contact forces of the individual wheels. The first substructure expediently includes at least a value range of 0 to 1 for a semi-active actuator and / or at least a value range of -1 to 1 for a fully active actuator. This is advantageous because it allows separate signals for the tension and compression stages of the actuator or the force direction of another wheel-specific actuator. Thus, wheel-specific actuators on the front and rear axles can be controlled simultaneously. The resulting influence on the average wheel contact forces allows the vehicle's behavior to be modified towards stability and / or agility.

[0021] Advantageously, the second substructure comprises a value range from -1 to 1, where -1 corresponds to a complete transfer of the roll moment to the front axle and 1 to a complete transfer of the roll moment to the rear axle. This is advantageous because, for example, the vehicle's self-steering behavior can be influenced during cornering. To enable, for instance, a lower steering input during cornering, an active roll moment with a strong front-axle bias can be applied to the vehicle.

[0022] Advantageously, the third substructure includes at least one predefined symmetrical value range for defining the requested roll moment at the vehicle level. This is beneficial because it allows the amplitude of a requested roll moment to be defined depending on vehicle characteristics, such as its weight.

[0023] Conveniently, the fourth substructure includes a value range from 0 to 1, where 0 corresponds to a minimum vehicle height and 1 to a maximum vehicle height. This is advantageous because it allows for easy adjustment of the vehicle height.

[0024] Advantageously, the fifth substructure comprises a value range from 0 to 1, where 0 corresponds to a minimum actuator stiffness and 1 to a maximum actuator stiffness. This is beneficial for simultaneously adjusting the actuator stiffness for each wheel individually using the data structure to stabilize a vehicle during a highly dynamic driving maneuver, such as an evasive lane change. The resulting influence on the wheel contact forces allows the vehicle's behavior to be modified towards improved stability.

[0025] The sixth substructure conveniently comprises a value range from 0 to 1, where 0 represents a low priority and 1 a high priority. This is advantageous for prioritizing the vehicle dynamics requirements over the respective chassis system.

[0026] The seventh substructure expediently comprises a value range from -1 to 1, where -1 corresponds to a complete conversion of the pitching moment at the front axle and 1 to a complete conversion of the pitching moment at the rear axle. This is advantageous because, for example, uncomfortable pitching or jerking in the longitudinal direction can thus ideally be prevented during acceleration or braking.

[0027] Advantageously, the eighth substructure includes at least one predefined symmetrical value range for specifying the requested pitching moment at the vehicle level. This is beneficial because it allows the amplitude of a requested pitching moment to be defined depending on vehicle characteristics, such as its own weight.

[0028] Conveniently, the ninth substructure includes a value range from 0 to 1, where 0 means no requirement for ground-hook control and 1 means a requirement for ground-hook control. This is advantageous for influencing the wheel contact forces of the individual wheels.

[0029] Furthermore, the invention relates to a method for generating a data structure for controlling a vehicle's chassis system. This allows the aforementioned advantages to be achieved. The invention also relates to a device with at least two functional units, wherein the functional units are configured to exchange a data structure according to the invention with each other for controlling a vehicle's chassis system with at least one actuator. This allows the aforementioned advantages to be realized. The functional units can be designed as dedicated electronic control units or as software modules running on the same control unit.

[0030] Brief description of the drawings

[0031] Advantageous embodiments of the invention are shown in the figures and explained in more detail in the following description.

[0032] It shows:

[0033] Figure 1 shows a schematic representation of a device according to the invention with at least two electronic control units which are configured to exchange a data structure according to the invention with each other.

[0034] Embodiments of the invention

[0035] The same reference numerals denote the same device components or the same process steps in all figures.

[0036] Figure 1 shows a schematic representation of a device 10 according to the invention with at least two electronic control units 11, 12, which are configured to exchange a data structure according to the invention with each other.

[0037] Preferably, such a device 10 is installed in a vehicle. A first control unit 11 is, for example, a central control unit or a brake control unit, and a second control unit 12 is, for example, a chassis system control unit. The device 10 can, for example, be used to control wheel- and / or axle-specific semi-active and active chassis systems, such as active damping and roll stabilization systems. Since chassis systems usually have a pure vertical dynamics control system that focuses primarily on occupant comfort, the data structure for superimposing this vertical dynamics control with the cascaded vehicle dynamics control system is required.

[0038] The data structure distinguishes between actuators that perform wheel-selective interventions, such as semi-active or active dampers, and actuators that perform axle-selective interventions, such as active roll stabilization systems.

[0039] To stabilize a vehicle during highly dynamic driving maneuvers, such as an evasive lane change, semi-active dampers can be used with the help of this data structure. This allows for the simultaneous, wheel-specific control of the adjustable dampers on the front and rear axles. The resulting influence on the average wheel contact forces can modify the vehicle's behavior towards improved stability.

[0040] Furthermore, the data structure is used to utilize the wheel-specific actuators to positively influence the vehicle's pitching behavior. This ideally prevents uncomfortable pitching or jerking movements in the longitudinal direction, for example, during acceleration or braking.

[0041] Using the interface defined by this data structure to an axle-specific chassis system, such as an active roll stabilization system, the self-steering behavior of a vehicle can be influenced, for example, during cornering. To enable, for instance, a lower steering input during cornering, an active roll moment with a strong front-axle bias can be applied to the vehicle.

[0042] The following data structure can be used to control semi-active and active suspension systems, for example, to control them as needed based on a physically based vehicle model and without the need to include specific actuator characteristics: Signal for controlling semi-active dampers or other wheel-specific actuators

[0043] • Separate signals for the compression and rebound stage of the damper or the force direction of another wheel-specific actuator

[0044] • Value range:

[0045] ■ [0;1] for semi-active dampers; 0=soft ... 1 =hard

[0046] ■ [-1 ;1] for fully active wheel-individual suspension system; -1 = force in the direction of movement of the actuator ... 1 = force against the direction of movement of the actuator. Signal for the distribution of the roll moment.

[0047] • Value range [-1 ;1]; -1 = 100% implementation at front axle ... 1 = 100% implementation at rear axle. Signal for providing roll moment.

[0048] • Value range [-5000Nm;5000Nm]; Amplitude of the requested roll moment at vehicle level; Signal for changing the vehicle height using individual wheel or axle actuators

[0049] • Value range [0;1]; 0 = minimum vehicle height ... 1 = maximum vehicle height. Signal for changing the body spring stiffness using individual wheel actuators.

[0050] • Value range [0;1]; 0 = minimum body spring stiffness ... 1 = maximum body spring stiffness. Signal for prioritizing the driving dynamics requirement over the respective chassis system.

[0051] • Value range: [0;1]; 0 = low priority ... 1 = high priority Signal for pitching moment distribution • Value range: [-1 ;1]; -1 = 100% implementation at front axle ... 1 = 100% implementation at rear axle

[0052] 8. Signal to provide pitching moment

[0053] • Value range [-5000Nm;5000Nm]; Amplitude of the requested pitch torque at vehicle level

[0054] 9. Signal for individual wheel request of a ground hook control

[0055] • Value range: [0;1 ]; 0=no request ... 1 =ground hook request

[0056] Using the described data structure, arbitration between vertical dynamics control and vehicle dynamics control can take place, for example, as follows: • Actuator request = (1 - Prioritization) * Vertical dynamics control request + Prioritization * Vehicle dynamics control request

Claims

Claims 1. Data structure for controlling a chassis system of a vehicle with at least one actuator that can be controlled to perform wheel-selective and / or axle-selective interventions, wherein the data structure comprises at least one of the following substructures: - a first substructure for setting a force direction of the actuator, - a second substructure for distributing a roll moment by means of the actuator, - a third substructure for providing the roll moment - a fourth substructure for changing the vehicle height using at least one actuator, - a fifth substructure for changing the stiffness of the actuator, - a sixth substructure for prioritizing vehicle dynamics requirements.

2. Data structure according to the preceding claim, further comprising at least one of the following substructures: - a seventh substructure for distributing a pitching moment by means of the actuator; - an eighth substructure to provide a pitching moment; - a ninth substructure for the wheel-specific requirement of a subordinate ground hook control.

3. Data structure according to one of the preceding claims, wherein the first substructure comprises at least a range of values ​​from 0 to 1 for a semi-active actuator and / or from -1 to 1 for a fully active actuator.

4. Data structure according to one of the preceding claims, wherein the second substructure comprises a value range from -1 to 1, where -1 corresponds to a complete implementation on the front axle and 1 to a complete implementation on the rear axle.

5. Data structure according to one of the preceding claims, wherein the third substructure comprises at least one predefined symmetrical value range for determining the requested roll moment at vehicle level.

6. Data structure according to one of the preceding claims, wherein the fourth substructure comprises a value range from 0 to 1, where 0 corresponds to a minimum vehicle height and 1 to a maximum vehicle height.

7. Data structure according to one of the preceding claims, wherein the fifth substructure comprises a range of values ​​from 0 to 1, where 0 corresponds to a minimum actuator stiffness and 1 to a maximum actuator stiffness.

8. Data structure according to one of the preceding claims, wherein the sixth substructure comprises a range of values ​​from 0 to 1, where 0 represents a low priority and 1 represents a high priority.

9. Data structure according to one of the preceding claims, wherein the seventh substructure comprises a value range from -1 to 1, where -1 corresponds to a complete implementation at the front axle and 1 to a complete implementation at the rear axle and / or wherein the eighth substructure comprises at least one predefined symmetrical value range for determining the requested pitching moment at vehicle level and / or wherein the ninth substructure comprises a value range from 0 to 1, where 0 signifies no request and 1 signifies a request for ground-hook control.

10. Method for generating a data structure for controlling a chassis system of a vehicle according to one of the preceding claims.

11. Device (10) with at least two electronic functional units (11, 12), wherein the functional units are configured to exchange a data structure according to one of the preceding claims with each other. for controlling a vehicle's chassis system with at least one actuator.

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