Method for populating a controller with data, and method for operating a motor vehicle

Abstract

A method for populating a controller for a motor vehicle with data includes providing a controller with a storage device, and generating a projected mathematical model of at least one section of a powertrain, including a transmission. The projected mathematical model describes the section of the powertrain with a gear ratio of 1 and is applicable to different transmissions. The projected mathematical model is stored in the storage device of the controller. A motor vehicle is also provided and operated accordingly.

Claims

1. A method for populating a controller for a motor vehicle with data, the method comprising: providing the controller with a storage device; producing a projected mathematical model of at least one section of a drive train with a transmission, wherein the projected mathematical model describes the drive train in a state with a transmission ratio of 1 and not other than 1; and storing the projected mathematical model in the storage device of the controller, wherein the projected mathematical model includes parameters and/or variables that are scalable according to actual transmission ratio information received from the motor vehicle so as to render the projected mathematical model reflective of an actual transmission of the motor vehicle having an actual transmission ratio other than 1 after the projected mathematical model is stored in the storage device.

2. The method according to claim 1, wherein the section of the drive train is modeled as at least two masses coupled to one another via a spring element and/or via a damping element.

3. A method for operating a motor vehicle, wherein the motor vehicle comprises a drive train with at least one transmission, and a controller, the method comprising: producing a projected mathematical model of at least one section of the drive train, wherein the projected mathematical model describes the drive train in a state with a transmission ratio of 1 and not other than 1; storing the projected mathematical model in a storage device of the controller; after the projected mathematical model is stored in the storage device, scaling parameters and/or variables of the projected mathematical model according to an actual transmission ratio of the at least one transmission such that the projected mathematical model models the at least one transmission, the at least one transmission having the actual transmission ratio other than 1; and generating at least one system matrix on the basis of the projected mathematical model and the scaled parameters and/or variables.

4. The method of claim 3, wherein the parameters and/or variables are scaled such that the projected mathematical model models the at least one section of the drive train.

5. The method of claim 3, wherein at least one motor vehicle function is controlled on the basis of the system matrix.

6. The method of claim 3, wherein a drive machine of the motor vehicle is controlled based on the system matrix.

7. The method of claim 3, wherein an active damping device of the motor vehicle is controlled based on the system matrix.

8. The method of claim 3, wherein the actual value of the transmission ratio of the transmission is a current actual value of the transmission ratio transmitted to the controller.

9. The method of claim 3, wherein the actual value of the transmission ratio is stored in the controller during the manufacture of the motor vehicle.

10. A motor vehicle comprising: a drive train comprising: a transmission having an actual transmission ratio, and a controller, wherein the motor vehicle is configured to carry out the method of claim 3.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Further advantages and properties can be found in the following description and the appended drawings to which reference is made.

(2) FIG. 1 shows a schematic view of a motor vehicle according to the invention;

(3) FIG. 2 shows a schematic flow diagram of the steps of a method according to the invention for populating a controller for a motor vehicle with data;

(4) FIG. 3(a) shows a mathematical model of a drive train;

(5) FIG. 3(b) shows a projected mathematical model of a drive train; and

(6) FIG. 4 shows a schematic flow diagram of the steps of a method according to the invention for operating a motor vehicle.

DETAILED DESCRIPTION OF THE DRAWINGS

(7) FIG. 1 shows a schematic view of a motor vehicle 10 which has a drive machine 12 and a drive train 14 which connects the drive machine 12 to at least one axle of the motor vehicle 10 in a force-transmitting fashion. In the example shown, the drive machine 12 is connected to a rear axle 16 of the motor vehicle.

(8) The motor vehicle 10 is therefore embodied with a rear-wheel drive. Alternatively, or additionally, the motor vehicle 10 can, however, also have a front-wheel drive.

(9) The drive machine 12 can comprise an internal combustion engine and/or an electric motor. In other words, the motor vehicle 10 can be embodied as a vehicle with an internal combustion drive or as an electric vehicle or as a hybrid vehicle which comprises an internal combustion engine and an electric motor.

(10) The drive train 14 comprises at least one transmission 20 which has a transmission ratio i. In the example illustrated in FIG. 1, the transmission 20 converts a rotational speed of a driveshaft 22 assigned to the drive machine 12 to a rotational speed of the rear wheels 18. In particular, the transmission 20 has a plurality of gears, wherein the transmission ratio i then depends on the gear which is engaged.

(11) If the motor vehicle is embodied as a hybrid vehicle, the drive train 14 can also comprise a transfer box which transmits torques from the internal combustion engine and electric motor to the driveshaft 22.

(12) A damping device 24 which is configured to actively damp disruptive rotational vibrations in the drive train 14 is optionally provided in the drive train 14.

(13) In addition, the motor vehicle 10 has a controller 26 which is configured to control at least one motor vehicle function.

(14) In particular, the controller 26 is an engine controller or motor controller and/or a controller of the damping device 24. Consequently, the controller 26 can be connected to the drive machine 12 and/or to the damping device 24 in a signal-transmitting fashion.

(15) The term “connected in a signal-transmitting fashion” is understood here to mean any type of cable-less or cable-bound connection which is suitable for transmitting data and/or signals. Signal-transmitting connections are indicated by dotted lines in FIG. 1.

(16) Alternatively, or additionally, the controller 26 is designed to control a drive function, a steering function and/or an interference suppression function. The drive function is, for example, to provide a predefined torque by the drive machine and/or to divide a torque between an internal combustion engine and an electric motor. The steering function can be to provide a predefined auxiliary torque for assisting the steering and/or to provide an adaptive steering sensation. The interference suppression function comprises, for example, suppressing rotational vibrations in the drive train 14 and/or suppressing disruptive reactions of the drive train on a steering wheel, for example “juddering on a smooth road.”

(17) In addition, the controller 26 can be connected in a signal-transmitting fashion to the transmission 20, in particular to a transmission controller 28.

(18) The controller can preferably be used universally for various types of drive trains, in particular for drive trains 14 with a different transmission ratio i.

(19) For this purpose, a projected mathematical model of the drive train 14 is stored in a storage device of the controller 26, wherein the controller 26 is populated with data by means of the method described below with reference to FIGS. 2 and 3.

(20) Firstly, the controller 26 is provided (Step S1). Secondly, a projected mathematical model of a section of the drive train 14 is produced which comprises the transmission 20 (Step S2).

(21) The projected mathematical model describes here the section of the drive train 14 with a transmission ratio of i=1. In other words, in the projected mathematical model the transmission 20 does not implement either a step up or a step down of the rotational speed or of the torque.

(22) For the sake of better understanding, step S1 will be explained in even more detail on the basis of the exemplary mathematical model illustrated in FIG. 3.

(23) In FIGS. 3 (a) and (b), which illustrate a mathematical model of the drive train 14 or a projected mathematical model of the drive train 14, the drive train 14 is in each case modeled as a damped harmonic oscillator.

(24) A first mass m.sub.1 represents here an effective mass of the components on a first side 30 of the transmission 20, while a second mass m.sub.2 represents an effective mass of the components on a second side 32 of the transmission 20.

(25) The two masses m.sub.1, m.sub.2 are coupled to one another by a transmission stage 34 with a transmission ratio i, a spring element 36 with a spring constant k, and a damping element 38 with a damping constant c. In addition, a torque f engages on the second mass m.sub.2.

(26) The transmission ratio i of the transmission stage 34 occurs here in such a way that in FIG. 3 (a) the rotational speed is multiplied by i from left to right, and the torque is divided by i from left to right.

(27) The transmission ratio 34, the spring element 36 and the damping element 38 together form a model of the transmission 20.

(28) The following coupled motion equations for the coordinates x.sub.1 and x.sub.2 of the masses m.sub.1 and m.sub.2 can be derived from the mathematical model shown in FIG. 3 (a):
m.sub.1{umlaut over (x)}.sub.1+ci(i{dot over (x)}.sub.1−{dot over (x)}.sub.2)+ki(ix.sub.1−x.sub.2)+0
m.sub.2{umlaut over (x)}.sub.2+ci({dot over (x)}.sub.2−i{dot over (x)}.sub.1)+k(x.sub.2−ix.sub.1)+f.

(29) The projected mathematical model from FIG. 3 (b) corresponds precisely to the mathematical model according to FIG. 3 (a), but with the fixed selection i=1 and a modeled spring constant {circumflex over (k)} and a modified damping constant ĉ. The motion equations are correspondingly
m.sub.1{umlaut over (x)}.sub.1+ĉ({dot over (x)}.sub.1−{dot over (x)}.sub.3)+{circumflex over (k)}(x.sub.1−x.sub.3)=0
m.sub.3{umlaut over (x)}.sub.3+ĉ({dot over (x)}.sub.3−{dot over (x)}.sub.1)+{circumflex over (k)}(x.sub.3−x.sub.1)={circumflex over (f)}.

(30) It is to be noted once again here that the mathematical model described above is only an example for the purpose of illustration. Of course, any suitable mathematical model for the drive train 14 can be selected.

(31) However, the mathematical model always includes motion equations and/or state equations which describe a rotational movement of shafts above and below the transmission 20. In an analogous fashion, the projected mathematical model always corresponds to the mathematical model of the drive train 14, but with a transmission ratio i=1.

(32) The projected mathematical model, in particular the associated motion equations and/or state equations, are stored in a storage device of the controller 26 (Step S3).

(33) The controller 26 can then be used universally for various types of drive trains, in particular for drive trains 14 with a different transmission ratio i.

(34) For this purpose, only the method steps described below with reference to FIGS. 3 and 4 have to be carried out.

(35) Firstly, parameters and/or variables of the projected mathematical model are scaled on the basis of an actual transmission ratio of the transmission 20 (Step S4), specifically in such a way that the projected mathematical model models the respective section of the drive train 14 which contains the transmission 20. In other words, a projected mathematical model with scaled parameters and/or variables is equivalent to a “real” mathematical model of the section of the drive train 14 which considers the transmission ratio.

(36) This step will be explained in more detail once more with reference to the model in FIG. 3.

(37) By comparing the abovementioned coupled motion equations for the coordinates x.sub.1 and x.sub.2 from the “real” mathematical model and the coupled motion equations for the coordinates x.sub.1 and x.sub.3 from the projected mathematical model it becomes apparent that using the following scalings the projected mathematical model is equivalent to the “real” model:

(38) $x_3=\frac{1}{i}{x}_2;\hat{f}=if;\hat{c}-i^{2}c;\hat{k}=i^{2}k;m_3=i^2{m}_2.$

(39) Once again, the illustrated model is also to be understood here as being a purely illustrative example of the basic principle that the parameters and/or variables of the projected mathematical model are scaled in order to model the real drive train 14.

(40) For this projection of the real drive train 14, the actual value of the transmission ratio i is clearly necessary.

(41) The actual value of the transmission ratio i, in particular a current actual value of the transmission ratio i, is preferably transmitted from the transmission 20 to the controller 26. In other words, the actual value of the transmission ratio i is not stored in the controller 26 manually and for each motor vehicle 10 individually.

(42) Instead, the controller 26 receives the actual value of the transmission ratio directly from the transmission 20, in particular from the transmission controller 28. If the transmission 20 has a plurality of gears, the current actual value of the transmission ratio i can also be transmitted to the controller 26.

(43) Alternatively, or additionally, the actual value of the transmission ratio i can be stored in the controller 26 during the manufacture of the motor vehicle 10.

(44) At least one system matrix is then generated (Step S5) on the basis of the projected mathematical model and the scaled parameters and/or variables. Furthermore, motion equations and/or state equations which result from the mathematical model of the drive train are solved, in particular numerically (Step S6).

(45) At least one of the vehicle functions described above can then be controlled by the controller 26 on the basis of the system matrix.

(46) In this context, the term “controlled on the basis of the system matrix” is to be understood as meaning that the system matrix itself, the solutions of the corresponding motion equations and/or the solutions of the corresponding state equations are used for the control.