Dependent limitation of multiple chassis actuators

Abstract

Method for limiting at least two chassis actuators of a vehicle that influence the lateral dynamics of the vehicle, comprising the following steps: - Determining a reference value for each control command relating to a target value, wherein the control command is directed to an actuator limited by the procedure; - Providing an independent limitation of the reference quantity for at least one actuator, wherein the independent limitation limits a force output in the reference quantity of one actuator and is independent of the force output of other actuators; - Providing a dependent limitation of the comparison quantity for multiple actuators, wherein the dependent limitation limits the comparison quantity of multiple force outputs of multiple actuators.

Description

FIELD OF THE INVENTION

[0001] The present invention relates to a method for limiting at least two chassis actuators that influence the lateral dynamics of a vehicle. SUMMARY OF THE INVENTION

[0002] Accordingly, it is provided: - a method for limiting at least two chassis actuators of a vehicle that influence the lateral dynamics of the vehicle, comprising the following steps: determining a comparison variable for each control command relating to a target variable, wherein the control command is directed to an actuator limited by the method; providing an independent limitation of the comparison variable for at least one actuator, wherein the independent limitation limits a force output in the comparison variable of an actuator and is independent of the force output of other actuators; providing a dependent limitation of the comparison variable for a plurality of actuators, wherein the dependent limitation limits the comparison variable of a plurality of force outputs of a plurality of actuators.

[0003] A sensor, also known as a detector, transducer, or probe, is a technical component that can qualitatively or quantitatively measure certain physical or chemical properties or conditions, such as temperature, humidity, pressure, speed, brightness, acceleration, pH value, ionic strength, electrochemical potential, and / or the material properties of its environment. These quantities are recorded using physical or chemical effects and converted into a processable electrical signal as sensor data.

[0004] Vehicle sensors are mountable or mounted on a vehicle. Vehicle sensors include optical sensors, such as cameras, lidar, radar, TOF, and other sensor technologies, such as acoustic sensors.

[0005] Chassis actuators are components in a vehicle that are used to control, regulate, or adjust the chassis. They are designed to optimize driving dynamics, safety, and ride comfort. Chassis actuators can be used in various types of vehicles, including cars, trucks, and aircraft.

[0006] There are different types of chassis actuators that can perform different functions and influence lateral dynamics, for example wheel brakes, shock absorbers, suspension systems, air suspension systems, active stabilizers to reduce the roll tendency of a vehicle in curves, steering actuators, wheel suspension actuators, actuators for vehicle level control, actuators for automatic damping control, actuators for vehicle dynamics control, such as (active) all-wheel drive systems, traction control, stability control.

[0007] In this application, the terms actuator(s) and chassis actuator(s) are used synonymously.

[0008] Control commands relate to a target variable, such as a deceleration that can be implemented as a deceleration force of 5000 N by a wheel brake. Based on this, the influence on the lateral dynamics due to the target variable, such as a deceleration of 5 kN by a wheel brake, can be determined. The quantified influence on the lateral dynamics due to the target variable is referred to as the reference variable.

[0009] The combination of several conditions is an AND chain of the conditions.

[0010] A projection is the mapping of one (or more) vectors from an n-dimensional space into a space with a lower dimension. For example, a point, i.e. a vector, in three-dimensional space can be projected onto a predetermined (two-dimensional) surface or (one-dimensional) line.

[0011] Computer program products typically comprise a sequence of instructions that, when the program is loaded, cause the hardware to perform a specific procedure leading to a specific result.

[0012] Control commands are directed to chassis actuators to influence a vehicle's driving dynamics. For example, there are control commands for braking or acceleration. Depending on the intended function of a control command, the control command is transmitted to one or more actuators, such as a drive, a wheel drive of a specific wheel, a wheel brake of a specific wheel, a wheel axle, or a wheelset.

[0013] Consequently, there are numerous actuators on a chassis that are capable of influencing a vehicle's lateral dynamics. The influence on lateral dynamics depends not only on the absolute force magnitude implemented at the force output of an actuator in accordance with a control command, but also on the force output of other actuators. The force output at the actuator thus indirectly influences lateral dynamics via a torque or angle at the wheel. Actuators on a chassis can cause a twisting or displacement of a vehicle's wheel, a braking / drive torque, and / or a change in the wheel contact force. A resulting change in the contact area between the wheel and the road can influence lateral dynamics.

[0014] For example, a small deceleration requested by only one wheel brake can have a greater impact on the lateral dynamics of the vehicle than a larger deceleration requested by two wheel brakes on one wheel axle.

[0015] Accordingly, the basic idea of ​​the invention is to determine, monitor and limit the influence on the lateral dynamics of a vehicle based on control commands, both individually and as a whole.

[0016] Accordingly, for each control command that affects a target variable, such as a deceleration, a comparison variable that quantifies the influence of the target variable on the lateral dynamics is to be determined.

[0017] It is intended to limit the reference value of a control command using independent and dependent limits. Independent limits are aimed at limiting the reference value of a force output of an actuator, while independent limits are dependent on the force outputs of other actuators.

[0018] Dependent limitations of the comparison quantity affect multiple actuators, with each dependent limitation limiting a coupling of force outputs in the comparison quantity of multiple actuators. The coupling can be a sum, a difference, or another relationship between multiple actuators.

[0019] Advantageous embodiments and further developments emerge from the further subclaims and from the description with reference to the figure of the drawing.

[0020] It may be useful to provide an independent limitation for each actuator.

[0021] It may be useful to provide a dependent limitation for each combination of actuators.

[0022] According to a preferred development of the invention, a number of N actuators is limited by means of the described method and the combination of the independent and dependent limitations of the N actuators results in an N-dimensional polytope which limits the working range of the N actuators.

[0023] An N-dimensional polytope is the N-dimensional generalization of a three-dimensional polyhedron or a two-dimensional polygon.

[0024] According to a preferred development of the invention, the comparison value of a control command directed to an actuator is projected into the working area, in particular onto the edge of the polytope, by means of a projection if the comparison value exceeds the limitation.

[0025] It is also useful if the projection of the comparison value is directed towards the origin.

[0026] It is also useful if a target value is determined for the projected comparison value and the control command is corrected according to the target value.

[0027] According to a preferred development of the invention, the limited actuators comprise a selection from the following list: Wheel brakes, front and / or rear axle drives, wheel drives, shock absorbers, suspension systems, air suspension systems, active stabilizers to stabilize the roll tendency of a vehicle, steering actuators, in particular of the rear axle, wheel suspension actuators, actuators for vehicle level control, actuators for automatic damping control, actuators for vehicle dynamics control, in particular all-wheel drive systems, traction control, stability control

[0028] It is understood that a control unit for a vehicle for controlling a plurality of chassis actuators which are designed to influence the lateral dynamics of a vehicle, with an interface to the chassis actuators, and with a computing unit which determines a limitation of the actuators by means of the method according to one of the preceding claims and checks whether control commands meet the limitation, wherein a control command is executed by the actuators if the check has shown that the control command meets the limitation, and in particular a control command is projected into a working area if the check has shown that the control command does not meet the limitation.

[0029] A computer program product according to a method of one embodiment of the invention executes the steps of a method according to the preceding description when the computer program product runs on a computer, in particular an in-vehicle computer. When the program in question is used on a computer, the computer program product produces an effect, namely the restriction of the working range of a group of actuators. TABLE OF CONTENTS OF THE DRAWINGS

[0030] The present invention will be explained in more detail below with reference to the exemplary embodiments shown in the schematic figures of the drawing. These show: Fig. 1 is a schematic block diagram of an embodiment of the invention.

[0031] The accompanying drawings are intended to provide a further understanding of embodiments of the invention. They illustrate embodiments and, in conjunction with the description, serve to explain principles and concepts of the invention. Other embodiments and many of the noted advantages will be apparent upon reference to the drawings. The elements of the drawings are not necessarily shown to scale relative to one another.

[0032] In the figure of the drawing, identical, functionally identical and effective elements, features and components are provided with the same reference symbols, unless otherwise stated. DESCRIPTION OF EMBODIMENTS

[0033] Fig.1 relates to a schematic block diagram of a method for limiting at least two chassis actuators of a vehicle that influence the lateral dynamics of the vehicle, comprising steps S1 to S3. In step S1, a comparison variable is determined for each control command relating to a target variable, the control command being directed to an actuator limited by the method. In step S2, an independent limitation in the comparison variable is provided for at least one actuator, the independent limitation limiting a force output in the comparison variable of one actuator and being independent of the force output of other actuators. In step S3, a dependent limitation of the comparison variable is provided for several actuators, the dependent limitation limiting a sum of force outputs in the comparison variable of several actuators. Reference symbol S1-S3 process steps

Claims

[1] Method for limiting at least two chassis actuators of a vehicle that influence the lateral dynamics of the vehicle, comprising the following steps: - determining (S1) a comparison variable for each control command relating to a target variable, the control command being directed to an actuator limited by the method; - Providing (S2) an independent limitation of the comparison variable for at least one actuator, wherein the independent limitation limits a force output in the comparison variable of an actuator and is independent of the force output of other actuators; - Providing (S3) a dependent limitation of the comparison variable for several actuators, wherein the dependent limitation limits the comparison variable of several force outputs of several actuators. [2] Method according to claim 1, which limits a number of N actuators, wherein the combination of independent and dependent limitations results in an N-dimensional polytope which in particular limits the working range of the N actuators. [3] Method according to one of the preceding claims, in particular according to claim 2, wherein the comparison value of a control command directed to a chassis actuator which exceeds a limitation is projected by means of a projection into the working area, in particular onto the edge of the polytope. [4] The method of claim 3, wherein the projection is directed towards the origin. [5] Method according to claim 3 or claim 4, wherein a target value is determined for the projected comparison value and the control command is implemented by the actuator in accordance with the target value. [6] Method according to one of the preceding claims, wherein the limited actuators comprise a selection from the following list: Wheel brakes, front and / or rear axle drives, all-wheel drive transfer cases and torque vectoring transmissions, wheel drives, wheel brakes, active shock absorbers, semi-active shock absorbers, suspension systems, active suspension systems, passive suspension systems, air suspension systems, active stabilizers to stabilize the roll tendency of a vehicle, steering actuators, in particular of the rear axle, wheel suspension actuators, actuators for vehicle level control, actuators for automatic damping control, actuators for vehicle dynamics control, in particular all-wheel drive systems, traction control, slip control, stability control. [7] Control unit for a vehicle for controlling a plurality of chassis actuators which are designed to influence the lateral dynamics of a vehicle, with an interface to the chassis actuators and with a computing unit which determines the limitations of the actuators by means of the method according to one of the preceding claims and checks whether control commands meet the limitations, wherein a control command is executed by an actuator if the check has shown that the control command meets the limitation and in particular a control command is projected into a working area if the check has shown that the control command does not meet the limitation.

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