METHOD FOR GENERATING A REFERENCE TRAJECTORY WITHIN A LANE, METHOD FOR OPERATING A VEHICLE, DATA PROCESSING APPARATUS, VEHICLE, AND COMPUTER-READABLE MEDIUM

Abstract

The disclosure relates to a method for generating a reference trajectory within a lane for a vehicle. The method comprises receiving at least one vehicle current state parameter describing a current state of the vehicle (S11). The current state of the vehicle comprises at least a current position of the vehicle. Furthermore, a destination parameter describing a destination to be reached by the vehicle (S12), and at least one route parameter describing a route for reaching the destination (S13) are received. Moreover, the method comprises estimating a power loss being caused when traveling from the current position of the vehicle to the destination (S14). The reference trajectory within the lane is determined such that it minimizes the power loss and leads to the destination (S15). Additionally, a method for operating a vehicle is presented. According to this method, a reference trajectory is generated in accordance with the above method (S21) and at least one control signal is provided for controlling a motion of the vehicle along the reference trajectory (S22). Furthermore, a data processing apparatus, a vehicle and a computer-readable medium are presented.

Claims

1. A method for generating a reference trajectory (RT) within a lane for a vehicle (V), comprising: receiving at least one vehicle current state parameter describing a current state of the vehicle, wherein the current state of the vehicle comprises at least a current position of the vehicle, receiving a destination parameter describing a destination to be reached by the vehicle, receiving at least one route parameter describing a route starting at the current position of the vehicle and ending at the destination, estimating a power loss being caused when traveling from the current position of the vehicle to the destination, the power loss (P.sub.loss) being a function of at least one vehicle state parameter describing a state of the vehicle along the route, the destination parameter and a traveling time, and determining the reference trajectory (RT) within the lane that minimizes the power loss (P.sub.loss) and leads to the destination.

2. The method according to claim 1, wherein the vehicle current state parameter and the vehicle state parameter each comprise at least one of a corresponding longitudinal position of the vehicle (V), a corresponding lateral positon of the vehicle (V), a corresponding yaw angle (ψ) of the vehicle, a corresponding longitudinal speed of the vehicle (V), a corresponding side-slip angle of the vehicle (V) or a corresponding yaw rate of the vehicle (V).

3. The method according to claim 1, wherein the reference trajectory (RT) is described by at least one of a reference longitudinal position, a reference lateral position, a reference yaw angle, a reference longitudinal speed or time.

4. The method according to claim 1, wherein the power loss (P.sub.loss) comprises at least one of a propulsion loss (P.sub.P,loss), a transmission loss (P.sub.T,loss), a tire loss (P.sub.Ti,loss) and a drag loss (P.sub.D,loss).

5. The method according to claim 1, wherein estimating the power loss (P.sub.loss) comprises using a predefined power loss function.

6. The method according to claim 1, comprising: integrating the power loss (P.sub.loss) over time in order to calculate an energy loss.

7. The method according to claim 1, wherein determining the reference trajectory (RT) comprises: respecting at least one of a drivable area, a desired speed, a minimum lateral margin, a maximum allowable side slip angle, a maximum available torque or a road friction coefficient as a boundary condition.

8. The method according to claim 7, wherein at least one of the drivable area, the desired speed, the minimum lateral margin, the maximum allowable side slip angle, the maximum available torque or the road friction coefficient is known or received.

9. The method according to claim 1, comprising: receiving the at least one vehicle current state parameter from a sensor unit.

10. A method for operating a vehicle (V), comprising: generating a reference trajectory (RT), wherein the generating comprises: receiving at least one vehicle current state parameter describing a current state of the vehicle, wherein the current state of the vehicle comprises at least a current position of the vehicle, receiving a destination parameter describing a destination to be reached by the vehicle, receiving at least one route parameter describing a route starting at the current position of the vehicle and ending at the destination, estimating a power loss being caused when traveling from the current position of the vehicle to the destination, the power loss (P.sub.loss) being a function of at least one vehicle state parameter describing a state of the vehicle along the route, the destination parameter and a traveling time, and determining the reference trajectory (RT) within the lane that minimizes the power loss (P.sub.loss) and leads to the destination, and providing at least one control signal for controlling a motion of the vehicle (V) along the reference trajectory (RT).

11. The method according to claim 10, wherein the control signal comprises a steering angle control signal.

12. The method according to claim 11, comprising: performing a pure pursuit control technique for controlling the steering angle (δ).

13. A data processing apparatus for carrying out a method for generating a reference trajectory (RT) within a lane for a vehicle (V), the data processing apparatus comprising a processor that performs steps comprising: receiving at least one vehicle current state parameter describing a current state of the vehicle, wherein the current state of the vehicle comprises at least a current position of the vehicle, receiving a destination parameter describing a destination to be reached by the vehicle, receiving at least one route parameter describing a route starting at the current position of the vehicle and ending at the destination, estimating a power loss being caused when traveling from the current position of the vehicle to the destination, the power loss (P.sub.loss) being a function of at least one vehicle state parameter describing a state of the vehicle along the route, the destination parameter and a traveling time, and determining the reference trajectory (RT) within the lane that minimizes the power loss (P.sub.loss) and leads to the destination.

14. A data processing apparatus for carrying out a method for operating a vehicle (V), the data processing apparatus comprising a processor that performs steps comprising: generating a reference trajectory (RT), wherein the generating comprises: receiving at least one vehicle current state parameter describing a current state of the vehicle, wherein the current state of the vehicle comprises at least a current position of the vehicle, receiving a destination parameter describing a destination to be reached by the vehicle, receiving at least one route parameter describing a route starting at the current position of the vehicle and ending at the destination, estimating a power loss being caused when traveling from the current position of the vehicle to the destination, the power loss (P.sub.loss) being a function of at least one vehicle state parameter describing a state of the vehicle along the route, the destination parameter and a traveling time, and determining the reference trajectory (RT) within the lane that minimizes the power loss (P.sub.loss) and leads to the destination, and providing at least one control signal for controlling a motion of the vehicle (V) along the reference trajectory (RT).

15. A vehicle (V) comprising: a data processing apparatus for carrying out a method for generating a reference trajectory (RT) within a lane for a vehicle (V), the data processing apparatus comprising a processor that performs steps comprising: receiving at least one vehicle current state parameter describing a current state of the vehicle, wherein the current state of the vehicle comprises at least a current position of the vehicle, receiving a destination parameter describing a destination to be reached by the vehicle, receiving at least one route parameter describing a route starting at the current position of the vehicle and ending at the destination, estimating a power loss being caused when traveling from the current position of the vehicle to the destination, the power loss (P.sub.loss) being a function of at least one vehicle state parameter describing a state of the vehicle along the route, the destination parameter and a traveling time, and determining the reference trajectory (RT) within the lane that minimizes the power loss (P.sub.loss) and leads to the destination.

16. A vehicle (V) comprising: a data processing apparatus for carrying out a method for operating a vehicle (V), the data processing apparatus comprising a processor that performs steps comprising: generating a reference trajectory (RT), wherein the generating comprises: receiving at least one vehicle current state parameter describing a current state of the vehicle, wherein the current state of the vehicle comprises at least a current position of the vehicle, receiving a destination parameter describing a destination to be reached by the vehicle, receiving at least one route parameter describing a route starting at the current position of the vehicle and ending at the destination, estimating a power loss being caused when traveling from the current position of the vehicle to the destination, the power loss (P.sub.loss) being a function of at least one vehicle state parameter describing a state of the vehicle along the route, the destination parameter and a traveling time, and determining the reference trajectory (RT) within the lane that minimizes the power loss (P.sub.loss) and leads to the destination, and providing at least one control signal for controlling a motion of the vehicle (V) along the reference trajectory (RT).

17. A computer-readable medium comprising instructions which, when executed by a data processing unit, cause the data processing unit to carry out a method for generating a reference trajectory (RT) within a lane for a vehicle (V), the data processing apparatus comprising a processor that performs steps comprising: receiving at least one vehicle current state parameter describing a current state of the vehicle, wherein the current state of the vehicle comprises at least a current position of the vehicle, receiving a destination parameter describing a destination to be reached by the vehicle, receiving at least one route parameter describing a route starting at the current position of the vehicle and ending at the destination, estimating a power loss being caused when traveling from the current position of the vehicle to the destination, the power loss (P.sub.loss) being a function of at least one vehicle state parameter describing a state of the vehicle along the route, the destination parameter and a traveling time, and determining the reference trajectory (RT) within the lane that minimizes the power loss (P.sub.loss) and leads to the destination.

18. A computer-readable medium comprising instructions which, when executed by a data processing unit, cause the data processing unit to carry out a method of operating a vehicle (V), the data processing unit comprising a processor that performs steps comprising: generating a reference trajectory (RT), wherein the generating comprises: receiving at least one vehicle current state parameter describing a current state of the vehicle, wherein the current state of the vehicle comprises at least a current position of the vehicle, receiving a destination parameter describing a destination to be reached by the vehicle, receiving at least one route parameter describing a route starting at the current position of the vehicle and ending at the destination, estimating a power loss being caused when traveling from the current position of the vehicle to the destination, the power loss (P.sub.loss) being a function of at least one vehicle state parameter describing a state of the vehicle along the route, the destination parameter and a traveling time, and determining the reference trajectory (RT) within the lane that minimizes the power loss (P.sub.loss) and leads to the destination, and providing at least one control signal for controlling a motion of the vehicle (V) along the reference trajectory (RT).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Examples of the disclosure will be described in the following with reference to the following drawings.

[0046] FIG. 1 shows steps of a method according to the present disclosure for generating a reference trajectory within a lane for a vehicle and of a method according to the present disclosure for operating a vehicle,

[0047] FIG. 2 illustrates a pure pursuit control technique for controlling a steering angle,

[0048] FIG. 3 schematically shows two exemplary reference trajectories which have been generated by the method for generating a reference trajectory within a lane for a vehicle of FIG. 1, and

[0049] FIG. 4 schematically shows a data processing apparatus according to the present disclosure comprising means for carrying out the methods of FIG. 1.

[0050] The figures are merely schematic representations and serve only to illustrate examples of the disclosure. Identical or equivalent elements are in principle provided with the same reference signs.

DETAILED DESCRIPTION

[0051] FIG. 1 shows a method for generating a reference trajectory RT within a lane for a vehicle V comprising steps S11 to S15 and a method for operating a vehicle comprising steps S21 and S22 (see also FIG. 3).

[0052] Step S11 of the method for generating a reference trajectory RT within a lane for a vehicle V comprises receiving at least one vehicle current state parameter describing a current state of the vehicle.

[0053] In the example as shown in the figures, the current state of the vehicle V is described by a position of the vehicle. Thus, in step S11, a longitudinal position of the vehicle, a lateral positon of the vehicle, and a yaw angle of the vehicle are received. These vehicle current state parameters may be expressed in a vehicle coordinate system, i.e. a coordinate system having its origin on the vehicle. Alternatively, a global coordinate system may be used.

[0054] Additionally, the current state of the vehicle may be described by a longitudinal speed of the vehicle, a side-slip angle of the vehicle or a yaw rate of the vehicle. Also these vehicle current state parameters may be expressed in a vehicle coordinate system or a global coordinate system.

[0055] The parameters describing the vehicle current state may be received from a navigation unit using GPS data. More generally, the vehicle current state parameters are received from as sensor unit.

[0056] Step S12 comprises receiving a destination parameter. The destination parameter describes a destination to be reached by the vehicle. The destination parameter may describe a position. Also the destination parameter may be received from a navigation unit using for example GPS data.

[0057] A further step S13 comprises receiving at least one route parameter. The route parameter describes a route starting at the current position of the vehicle V and ending at the destination, i.e. a route leading from the current position of the vehicle to the destination. As has been described before, a route defines which road or lane is to be taken.

[0058] It is obvious that the vehicle current state and the destination parameter need to be known in order to be able to calculate the at least one route parameter. However, of course different routes may be available for connecting a vehicle having a current state and a destination.

[0059] Thereafter, a step S14 comprises estimating a power loss P.sub.loss being caused when traveling from the current position of the vehicle V to the destination along the route.

[0060] The power loss P.sub.loss is a function of at least one vehicle state parameter describing a state of the vehicle along the route, the destination parameter and a traveling time.

[0061] The estimated power loss P.sub.loss comprises a propulsion loss, a transmission loss, a tire loss and a drag loss.

[0062] In the present example, the propulsion loss P.sub.P,loss describes a loss occurring in a propulsion system of the vehicle V, e.g. in an electric motor and a corresponding inverter unit. The propulsion loss P.sub.P,loss is estimated as a function of the delivered propulsion torque T. It is assumed that the propulsion loss P.sub.P,loss may be described by a quadratic function over the torque T which reads as follows:

P.sub.P,loss=a.sub.1T.sup.2+a.sub.2T+a.sub.3

[0063] The parameters a.sub.1, a.sub.2, a.sub.3 depend from a rotational speed of the propulsion motor which may be an electric motor.

[0064] The propulsion loss P.sub.P,loss is assessed on a test bench using several operational points of the propulsion system. The parameters a.sub.1, a.sub.2, a.sub.3 of the above formula are determined by performing a curve fit.

[0065] The transmission loss P.sub.T,loss comprises a loss occurring in a transmission. The transmission loss P.sub.T,loss is also described by a quadratic function over torque T. As before, the transmission loss P.sub.T,loss is assessed on a test bench by operating the transmission in a number of operational points. Subsequently, a quadratic curve fit is performed. Consequently, the transmission loss P.sub.T,loss can be described by the following formula:

P.sub.T,loss=b.sub.1T.sup.2b.sub.2T+b.sub.3

[0066] The parameters b.sub.1, b.sub.2, b.sub.3 depend from a rotational speed of the transmission and are determined when performing the curve fit.

[0067] In the present example, one component of the tire loss P.sub.Ti,loss is assumed to be a longitudinal slip loss P.sub.Sx,loss. The longitudinal slip loss P.sub.Sx,loss is calculated using the following formula, wherein the longitudinal slip loss of each of the four wheels i=1 to i=4 of the vehicle are cumulated:

[00001]$P_{\mathrm{Sx},\mathrm{loss}}=\underset{i=1}{\overset{4}{.Math.}}{F}_{xi}\left(r_{ei}{\omega }_i-v_{xwi}\right)$

[0068] In this formula, F.sub.xi is the longitudinal force acting on wheel i in the x direction.

[0069] The longitudinal velocity of the center of the wheel i, i.e. the velocity of the center of the wheel i along the x direction is denoted v.sub.xwi. The parameter re, is the effective radius of the wheel i and ω.sub.i is the rotational velocity of the wheel i.

[0070] If a linear tire model is used and the resulting expression is linearized, the above formula can be rewritten as follows:

[00002]$P_{\mathrm{Sx},\mathrm{loss}}={.Math.}_{i=1}^4\left(\frac{v_{xi}{n}_i^2}{C_{xj}{r}_{ei}^2}{T}_{mi}^2\right)$

[0071] In this formula C.sub.xj is the longitudinal tire stiffness of the tires of axle j. The parameter n.sub.i is the rotational speed of the respective wheel i of the axle and T.sub.mi is the torque transmitted by the wheel i. The parameter v.sub.xi is the longitudinal velocity of the wheel i. The parameter r.sub.ei again relates to the effective radius of the wheel i.

[0072] Another component of the tire loss P.sub.Ti,loss is assumed to be a lateral slip loss P.sub.Sy,loss. The lateral slip loss P.sub.Sy,loss can be calculated as follows:

P.sub.Sy,loss=Σ.sub.i=1.sup.4F.sub.yi(v.sub.yi−v.sub.xiδ.sub.i)

[0073] In this expression F.sub.yi is the lateral force acting on wheel i. The parameter v.sub.yi is the lateral velocity of the wheel i and v.sub.xi is the longitudinal velocity of the wheel i. δ.sub.i is the steering angle of wheel i.

[0074] If again a linear tire model is used and the resulting expression is linearized, the above formula can be rewritten as follows:

P.sub.Sy,loss=Σ.sub.i=1.sup.4C.sub.yiα.sub.i.sup.2v.sub.x

[0075] In this expression, C.sub.yi is the lateral tire stiffness of the wheel i and α.sub.i is the tire slip angle of the wheel i. v.sub.x is the longitudinal velocity of the vehicle.

[0076] An additional component of the tire loss is the rolling resistance power loss P.sub.RR,loss which may be calculated as follows:

[00003]$p_{\mathrm{RR},\mathrm{loss}}={.Math.}_{i=1}^4{\omega }_i{F}_{zi}{r}_0\left(q_1+q_2\frac{F_{xi}}{F_{z0}}+q_3.Math.\frac{v_{xi}}{v_{ref}}.Math.+{q_4\left(\frac{v_{xi}}{v_{ref}}\right)}^4\right)$

[0077] In the above formula, the parameters r.sub.0, q.sub.1, q.sub.2, q.sub.3, q.sub.4, v.sub.ref and F.sub.z0 are obtained through tire measurements. F.sub.zi is a force acting on the wheel i in the z direction. As before, v.sub.xi is the longitudinal velocity of the wheel i, F.sub.xi is the longitudinal force acting on wheel i in the x direction, and ω.sub.i is the rotational velocity of the wheel i.

[0078] Thus, the tire loss P.sub.Ti,loss is the sum of the longitudinal slip loss P.sub.Sx,loss, the lateral slip loss P.sub.Sy,loss, and the rolling resistance power loss P.sub.RR,loss.

[0079] As has been mentioned above, the drag loss P.sub.D,loss may be calculated as a function of a drag coefficient, the density of air and the speed of the vehicle.

[0080] The different types of losses may be summed up in a power loss function. Thus, estimating the power loss P.sub.loss comprises using a predefined power loss function.

[0081] In case the energy losses are of interest, the power loss P.sub.loss may be integrated over time. The result is an energy loss occurring during the integration time. The integration time may be the travelling time.

[0082] Once, the power loss function is known, in step S15 a reference trajectory RT may be determined which minimizes the power loss function.

[0083] The reference trajectory RT may be described by a reference longitudinal position along direction x, a reference lateral position along a direction y, and a reference yaw angle ψ. In the present example, the reference longitudinal position, the reference lateral position, and the reference yaw angle are functions over traveling time.

[0084] Additionally, the reference trajectory RT may be described by a reference longitudinal speed.

[0085] It is understood that the above minimization problem is subject to several boundary conditions.

[0086] First of all, the reference trajectory RT must lead to the destination.

[0087] Furthermore, the reference trajectory RT must not exit the drivable lanes of the route. In other words, a drivable area needs to be respected. The vehicle V must stay within the drivable area at all time.

[0088] In order to allow safe travelling of the vehicle V, also minimum lateral margins with respect to a border of the drivable area must be respected.

[0089] A further boundary condition may relate to a maximum allowable side slip angle. This parameter may be chosen such that the vehicle stays stable and controllable at any time.

[0090] Moreover, a maximum available torque may be respected which is a characteristic of the propulsion unit and especially a propulsion motor of the vehicle V.

[0091] An additional boundary condition may relate to a road friction coefficient.

[0092] Furthermore, a desired speed may be respected as a boundary condition. The desired speed may be described by an allowable maximum speed and an allowable minimum average speed.

[0093] It is noted that the desired speed is used for calculating the reference trajectory only. The actual speed when driving along the reference trajectory may differ therefrom.

[0094] In the example shown in the figures, the above-mentioned boundary conditions are known, i.e. provided by a storage unit of the vehicle.

[0095] The reference trajectory may be used in a method for operating a vehicle comprising steps S21 and S22.

[0096] Step S21 relates to the generation of the reference trajectory RT and comprises steps S11 to S15.

[0097] Step S22 comprises providing at least one control signal for controlling a motion of the vehicle along the reference trajectory.

[0098] In the present example, the control signal comprises a steering angle control signal. This means that the steering angle δ of the vehicle is controlled such that the vehicle follows the reference trajectory RT.

[0099] To this end, a pure pursuit control technique may be performed for controlling the steering angle δ.

[0100] This control technique is explained in connection with FIG. 2, where a vehicle V having a length L is shown.

[0101] The vehicle V intends to follow the reference trajectory RT which is represented as a straight line in FIG. 2 for the ease of explanation. It is understood that the reference trajectory RT could as well be curved which is closer to reality than a straight reference trajectory.

[0102] The pure pursuit control technique is a geometric path tracking control technique which uses only the geometry of the vehicle kinematics and the reference trajectory. The pure pursuit control technique ignores dynamic forces and assumes a no-slip condition of the vehicle.

[0103] In this context, a target point TP on the reference trajectory RT is used. The target point TP is ahead of the vehicle V at a fixed and known distance l.sub.d from the vehicle. The distance l.sub.d may be called a look ahead distance.

[0104] An angle between the direction of l.sub.d and the direction of the length L of the vehicle V is designated β. Also β is known and may be called a look ahead angle.

[0105] The objective is to steer the vehicle to the target point TP. To this end, the vehicle V would need to travel along curve C which has a radius R and a center point M.

[0106] In this context, a center of the rear axle of the vehicle is used as reference point on the vehicle. This point, the center point M and the target point TP form a triangle.

[0107] The portion of the reference trajectory being located within this triangle has a length l.sub.0 which can be expressed as follows:

[00004]$l_0=\sin \left(2\beta \right)R$$l_0=\sin \left(\frac{\pi }{2}-\beta \right)l_d$

[0108] This results in the following equation

[00005]$\frac{R}{\sin \left(\frac{\pi }{2}-\beta \right)}=\frac{l_d}{\sin \left(2\beta \right)}$

[0109] This equation can be rewritten as

[00006]$2R=\frac{l_d}{\sin \left(\beta \right)}$

[0110] The so-called bicycle model provides the following dependency of the radius R, the length of the vehicle L and the steering angle δ:

[00007]$R=\frac{L}{\tan \left(\delta \right)}$

[0111] Thus, the steering angle δ can be expressed as

[00008]$\delta =\mathrm{arc}\tan \left(2L\frac{\sin \left(\beta \right)}{l_d}\right)$

[0112] It is noted that the look ahead distance l.sub.d can be varied based on the vehicle speed.

[0113] FIG. 3 schematically shows two exemplary reference trajectories RT (cf. FIG. 3 a) and FIG. 3 b)) which have been generated by the method for generating a reference trajectory RT within a lane for a vehicle V as described above. Using the pure pursuit control technique, the vehicle V is able to reliably follow these reference trajectories RT.

[0114] In order to illustrate the difference over known reference trajectories, both FIG. 3 a) and FIG. 3 b) also show a dotted line representing the middle of the respective lane, i.e. a trajectory always having an identical lateral distance from the border of the lane on both sides.

[0115] In the example of FIG. 3 a), the minimization of the power loss P.sub.loss results in the minimization of the travel distance. Thus, in this example, the reference trajectory RT has a minimum length which of course respects boundary conditions such as the drivable area and the minimum lateral margins.

[0116] In the example of FIG. 3 b) the lateral tire slip loss is comparatively high. The corresponding kind of loss is reduced by increasing the curve radius of the reference trajectory RT. Thus, in this example, the reference trajectory RT minimizing the power loss maximizes the curve radius. This leads to the fact that the reference trajectory RT being calculated by the method as described above is longer than a reference trajectory following the middle of the lane (cf. dotted line).

[0117] FIG. 4 shows a data processing apparatus 10 comprising first means 12 for carrying out the method for generating a reference trajectory RT within a lane for a vehicle V.

[0118] Moreover, the data processing apparatus 10 comprises second means 14 for providing a control signal for controlling a motion of the vehicle V along the reference trajectory RT. In the present example, the control signal relates to a steering angle δ of a steering system 16 of the vehicle V.

[0119] The first means 12 and the second means 14 together form a third means 18 for carrying out the method for operating the vehicle V.

[0120] In more detail, the first means 12 comprises a data processing unit 20, e.g. a computer, on which a computer program product may be executed.

[0121] The computer program product comprises instructions which, when the program is executed by the data processing unit 20, cause the data processing unit 20 to carry out the method for generating a reference trajectory RT within a lane for a vehicle V.

[0122] The first means 12 additionally comprise a computer-readable medium 22 which may also be designated a storage unit. The computer-readable medium 22 comprises instructions which, when executed by the data processing unit 20, cause the data processing unit 20 to carry out the method for generating a reference trajectory RT within a lane for a vehicle V.

[0123] The data processing unit 20 and the computer-readable medium 22 interact with each other in order to generate the reference trajectory RT, i.e. in order to perform the method for generating a reference trajectory RT within a lane for a vehicle V.

[0124] As an output, the first means 12 provides a reference longitudinal position, a reference lateral position, a reference yaw angle, and a reference longitudinal speed over time which describe the reference trajectory RT.

[0125] The second means 14 receives these parameters describing the reference trajectory RT as an input.

[0126] In more detail, the second means 14 comprises a data processing unit 24, e.g. a computer, on which a computer program product may be executed.

[0127] The computer program product comprises instructions which, when the program is executed by the data processing unit 24, cause the data processing unit 24 to provide a control signal for controlling a motion of the vehicle V along the reference trajectory RT which is a control signal relating to the steering angle δ in the present disclosure.

[0128] The second means 14 additionally comprise a computer-readable medium 26 which may also be designated a storage unit. The computer-readable medium 26 comprises instructions which, when executed by the data processing unit 24, cause the data processing unit 24 to provide the control signal.

[0129] The data processing unit 24 and the computer-readable medium 26 interact with each other in order to provide the control signal.

[0130] The second means 14 thus provides the steering angle δ as an output which is received by the steering system 16 of the vehicle V.

[0131] The steering system 16 comprises a steering angle sensing unit 32 which is configured for detecting a current steering angle δ.

[0132] The current steering angle δ is fed back to the data processing apparatus 10, more precisely to the second means 14 such that the steering angle δ can be controlled in a closed loop manner.

[0133] Moreover, the vehicle V comprises a position sensor 34, e.g. using a GPS signal. The sensing results of the position sensor 34 are provided to the data processing apparatus 10, especially to the first means 12. The position sensor 34 may provide a longitudinal position, a lateral position and a yaw angle of the vehicle V.

[0134] Additionally, the vehicle V comprises an inertial measurement unit 36 which is able to detect a yaw rate of the vehicle and provide the yaw rate to the data processing apparatus 10, especially to the first means 12.

[0135] The vehicle also comprises a speed sensing unit 38 which is able to detect or estimate a longitudinal speed of the vehicle V. The speed sensing unit 38 is configured for providing the detection result to the data processing apparatus 10, especially to the first means 12.

[0136] The steering angle sensing unit 32, the position sensor 34, the inertial measurement unit 36 and the speed sensing unit 38 may be summarized as a sensor unit 40.

[0137] The sensor unit 40 thus is configured for providing vehicle current state parameters describing a current state of the vehicle V to the data processing apparatus 10 and in particular the first means 12.

[0138] The destination parameter and the route parameter may be received from a navigation unit 28

[0139] Also boundary conditions as described above and generally designated with reference sign 30 may be received. Alternatively, the boundary conditions may be stored on the computer-readable media 22, 26.

[0140] Other variations to the disclosed examples can be understood and effected by those skilled in the art in practicing the claimed disclosure, from the study of the drawings, the disclosure, and the appended claims. In the claims the word “comprising” does not exclude other elements or steps and the indefinite article “a” or “an” does not exclude a plurality. A single processor or other unit may fulfill the functions of several items or steps recited in the claims. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. A computer program may be stored/distributed on a suitable medium such as an optical storage medium or a solid-state medium supplied together with or as part of other hardware, but may also be distributed in other forms, such as via the Internet or other wired or wireless telecommunication systems. Any reference signs in the claims should not be construed as limiting the scope of the claims.

LIST OF REFERENCE SIGNS

[0141] 10 data processing apparatus [0142] 12 first means [0143] 14 second means [0144] 16 steering system [0145] 18 third means [0146] 20 data processing unit [0147] 22 computer-readable medium [0148] 24 data processing unit [0149] 26 computer-readable medium [0150] 28 navigation unit [0151] 30 boundary condition [0152] 32 steering angle sensing unit [0153] 34 position sensor [0154] 36 inertial measurement unit [0155] 38 speed sensing unit [0156] 40 sensor unit [0157] a.sub.1 parameter [0158] a.sub.2 parameter [0159] a.sub.3 parameter [0160] b.sub.1 parameter [0161] b.sub.2 parameter [0162] b.sub.3 parameter [0163] C curve [0164] C.sub.xj longitudinal tire stiffness of the tires of axle j [0165] C.sub.yi lateral tire stiffness of the wheel i [0166] F.sub.xi longitudinal force on wheel i [0167] F.sub.yi lateral force on wheel i [0168] F.sub.zi force acting on the wheel i in the z direction [0169] F.sub.z0 parameter obtained through tire measurement [0170] i wheel index [0171] j axle index [0172] l.sub.0 length [0173] l.sub.d look ahead distance [0174] M center point [0175] n.sub.i rotational speed of the wheel i [0176] P.sub.loss power loss [0177] P.sub.D,loss drag loss [0178] P.sub.P,loss propulsion loss [0179] P.sub.Ti,loss tire loss [0180] P.sub.Sx,loss longitudinal slip loss [0181] P.sub.Sy,loss lateral slip loss [0182] P.sub.T,loss transmission loss [0183] P.sub.RR,loss rolling resistance power loss [0184] q.sub.1 parameter obtained through tire measurement [0185] q.sub.2 parameter obtained through tire measurement [0186] q.sub.3 parameter obtained through tire measurement [0187] q.sub.4 parameter obtained through tire measurement [0188] R radius [0189] r.sub.0 parameter obtained through tire measurement [0190] r.sub.ei effective radius of the wheel i [0191] RT reference trajectory [0192] S11 method step [0193] S12 method step [0194] S13 method step [0195] S14 method step [0196] S15 method step [0197] S21 method step [0198] S22 method step [0199] T propulsion torque [0200] T.sub.mi torque transmitted by wheel i. [0201] TP target point [0202] V vehicle [0203] v.sub.ref parameter obtained through tire measurement [0204] v.sub.xi longitudinal velocity of the wheel i [0205] v.sub.xwi velocity of the center of the wheel i along the x direction [0206] v.sub.yi lateral velocity of the wheel i [0207] x longitudinal direction [0208] y lateral direction [0209] α.sub.i tire slip angle of the wheel i [0210] β look ahead angle [0211] δ steering angle [0212] δ.sub.i steering angle of wheel i [0213] ψ yaw angle [0214] ω.sub.i rotational velocity of the wheel i