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DE-102024210822-A1 - Method for controlling a drive motor of a motor vehicle

DE102024210822A1DE 102024210822 A1DE102024210822 A1DE 102024210822A1DE-102024210822-A1

Abstract

Method for controlling a drive motor (2) of a motor vehicle, wherein the motor vehicle has a drive train (1) with the drive motor (2), at least one wheel (6) driven by the drive motor (2) and at least one mechanical component for transmitting the torque provided by the drive motor (2) to the at least one wheel (6), wherein the torque provided by the drive motor (2) is controlled in order to minimize torsional vibrations in the drive train (1), wherein the control of the torque provided by the drive motor (2) is carried out using a state space model representing the drive train (1) of the motor vehicle and state variables of a controller derived therefrom, wherein the controller is designed by pole specification in the state space.

Inventors

  • Felix Pradel
  • Johannes Milaev

Assignees

  • Schaeffler Technologies AG & Co. KG

Dates

Publication Date
20260513
Application Date
20241112

Claims (7)

  1. Method for controlling a drive motor (2) of a motor vehicle, wherein the motor vehicle has a drive train (1) with the drive motor (2), at least one wheel (6) driven by the drive motor (2) and at least one mechanical component for transmitting the torque provided by the drive motor (2) to the at least one wheel (6), wherein the torque provided by the drive motor (2) is controlled in order to minimize torsional vibrations in the drive train (1), wherein the control of the torque provided by the drive motor (2) is carried out using a state space model representing the drive train (1) of the motor vehicle and state variables of a controller derived therefrom, wherein the controller is designed by pole specification in the state space.
  2. Procedure according to Claim 1 , wherein the state space model is described by two systems of differential equations, where a first system of differential equations describes the dynamic behavior of the drive train (1) depending on the torque of the drive motor (2) and a second system of differential equations describes a vibration behavior of the drive train (1) depending on torque changes of the drive motor (2).
  3. Procedure according to Claim 1 or 2 , where the pole selection is made to minimize torsional vibrations in the drive train (1), and the two differential equation systems are used in a closed control loop to determine a target torque of the drive motor (2).
  4. Procedure according to one of the Claims 1 until 3 , where, based on the state space model, a wheel speed, a torsional angle of a drive shaft (3) of the drive train (1), a torque requested by a driver, a speed of the drive motor (2) and an actual torque of the drive motor (2) are determined as state variables.
  5. Control device (9) comprising at least one control unit, wherein the control unit is used to carry out a procedure according to one of the Claims 1 until 4 is trained.
  6. motor vehicle comprising a drive motor (2), a drive train (1) and a control device (9) according to Claim 5 .
  7. A computer program that includes instructions which, when executed by a computer, cause it to perform a procedure according to one of the Claims 1 until 4 to carry out.

Description

The present invention relates to a method for controlling a drive motor of a motor vehicle. It further relates to a control device for a motor vehicle and to a motor vehicle. The powertrain of a motor vehicle comprises several components, in particular the drive motor, the wheels driven by the drive motor, and at least one mechanical component for transmitting the torque provided by the drive motor to the driven wheels. The moments of inertia of the components, their stiffness, and damping within the powertrain determine the dynamic behavior of the system. This can lead to vibrations in the powertrain, especially torsional vibrations of a shaft, which are perceived as a disturbing judder. One option is to implement judder damping, which uses relatively complex and expensive low-pass and high-pass filters that require calibration. It is therefore an object of the present invention to provide a method for controlling a drive motor of a motor vehicle which achieves damping of torsional vibrations in the drive train in a simple manner. This problem is solved by the subject matter of the independent patent claim. Advantageous embodiments and further developments are the subject matter of the dependent claims. According to one aspect of the invention, a method for controlling a drive motor of a motor vehicle is provided, wherein the motor vehicle has a drivetrain comprising the drive motor, at least one wheel driven by the drive motor, and at least one mechanical component for transmitting the torque provided by the drive motor to the at least one wheel. The mechanical component for transmitting the torque can, in particular, be one or more shafts. The torque provided by the drive motor is controlled to minimize torsional vibrations in the drivetrain. The control of the torque provided by the drive motor is achieved using a state-space model representing the drivetrain of the motor vehicle and state variables of a controller derived therefrom, wherein the controller is designed by pole specification in the state space. The state-space model represents the relationships between all input variables, output variables, and state variables in the form of vectors and matrices. State variables of the state model can include, in particular, the wheel speed, the engine speed, the torque supplied by the drive motor, and the torsion angle of a drivetrain shaft. An input variable can be, in particular, the torque requested by the driver of the vehicle, and an output variable the torque actually supplied. The method has the advantage of not requiring a multitude of parameters that necessitate complex calibration. Furthermore, it is easy to implement for providing vibration damping in a motor vehicle. The pole setting makes it possible to adjust the control so that torsional vibrations are strongly dampened, while still providing a realistic torque through the drive motor. The state-space model is described by two systems of differential equations. The first system describes, in particular, the dynamic behavior of the drivetrain as a function of the drive motor's torque, and the second system describes the drivetrain's vibration behavior as a function of changes in the drive motor's torque. The dynamic behavior of the drivetrain as a function of the drive motor's torque can be described by... φ¨1=−dJ1∗φ˙1+dJ1∗φ˙2−cJ1∗φ1+cJ1∗φ2+iG∗ηGJ1∗Mφ¨2=dJ2∗φ˙1−dJ2∗φ˙2+cJ2∗φ1−cJ2∗φ2 The constants c and d characterize the vibration and damping behavior in the drive train, where c is the stiffness, the quantities J 1 , φ 1 , φ̇ 1 , φ̈ 1 are the moment of inertia and the angle of rotation of the shaft, respectively, while the quantities J 2 , φ 2 , φ̇ 2 , φ̈ 2 denote the moment of inertia and the angle of rotation and its derivatives of the driven wheel. The quantities i G and η G denote the translation and efficiency of a gearbox in the drive train, and M the torque provided by the drive motor. According to one embodiment, the pole setting is used to minimize torsional vibrations in the drivetrain. This can be achieved by setting the imaginary part of the eigenvalues to zero. However, it has been found that it is advantageous to set the poles in such a way that vibrations do occur, but are strongly damped, since complete suppression of vibrations typically leads to unrealistic target torques. Thus, the pole setting can be achieved, for example, by ensuring that the vibrations lie within a predefined vibration range and that the manipulated variable lies within a predefined manipulated variable range. The vibration range is defined in such a way that no disruptive vibrations result in the vehicle. The two systems of differential equations can be used in a simulation to make suitable pole specifications and to determine a target torque for the drive motor. Based on the state space model, state variables can be determined in particular as a wheel speed, a torsion angle, a drive shaft of the drive train and/or a speed of the drive motor. Accordin