Method for stabilizing a two-wheeled vehicle during cornering

Abstract

In a method for stabilizing a two-wheeled vehicle during cornering, a drifting of the rear wheel or an understeering of the front wheel is inferred on the basis of measured values including the actual steering angle, and the two-wheeled vehicle is stabilized by altering the torque at the front wheel and/or the rear wheel.

Claims

1. A method that stabilizes a two-wheeled vehicle during cornering, comprising: measuring at least one driving state value including an actual steering angle; inferring, based on the at least one driving state value, one of a drifting of a rear wheel or an understeering of a front wheel; and stabilizing the two-wheeled vehicle by altering a torque at least one of at the front wheel and at the rear wheel.

2. The method as recited in claim 1, wherein the at least one driving state value further includes measured acceleration values, and wherein a critical driving state is inferred from the measured acceleration values and the actual steering angle.

3. The method as recited in claim 2, wherein a nominal steering angle is ascertained and, from a deviation between the actual steering angle and the nominal steering angle, the one of the drifting of the rear wheel or the understeering of the front wheel is inferred.

4. The method as recited in claim 3, wherein the nominal steering angle is ascertained from an angle of inclination and a vehicle velocity.

5. The method as recited in claim 4, wherein the angle of inclination is calculated from measured acceleration values.

6. The method as recited in claim 4, wherein a maximum allowable drift angle is specified.

7. The method as recited in claim 4, wherein a driving style is selected and specified among multiple driving styles.

8. The method as recited in claim 3, wherein a braking torque at the at least one of the front wheel and the rear wheel is altered.

9. The method as recited in claim 3, wherein an engine torque acting on the rear wheel is altered.

10. A regulating unit that stabilizes a two-wheeled vehicle during cornering, comprising: a control unit including a processor configured to perform the following: measuring at least one driving state value including an actual steering angle; inferring, based on the at least one driving state value, one of a drifting of a rear wheel or an understeering of a front wheel; and stabilizing the two-wheeled vehicle by altering a torque at least one of at the front wheel and at the rear wheel.

11. A non-transitory, computer-readable data storage medium storing a computer program having program codes which, when executed on a computer, performs a method that stabilizes a two-wheeled vehicle during cornering, the method comprising: measuring at least one driving state value including an actual steering angle; inferring, based on the at least one driving state value, one of a drifting of a rear wheel or an understeering of a front wheel; and stabilizing the two-wheeled vehicle by altering a torque at least one of at the front wheel and at the rear wheel.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 shows in a schematic representation, a motorcycle in a cornering maneuver where the front wheel is understeering.

(2) FIG. 2 shows a representation corresponding to FIG. 1, however, with a drifting rear wheel.

(3) FIG. 3 shows a block diagram for stabilizing the two-wheeled vehicle during cornering.

(4) FIG. 4 shows a block representation including the input and output quantities of a torque control that is used to stabilize the two-wheeled vehicle during cornering.

DETAILED DESCRIPTION OF THE INVENTION

(5) Identical or corresponding components are provided with the same reference numerals in the figures.

(6) In a highly schematized view, FIGS. 1 and 2 show a two-wheeled vehicle during cornering that has a front wheel 1 and a rear wheel 2; front wheel 1 being adjusted about a steering axis 3 by actual steering angle .sub.a. In FIG. 1, the vehicle understeers; accordingly actual steering angle .sub.a is positive. In FIG. 2, the vehicle oversteers; actual steering angle .sub.a is negative. In both FIGS. 1 and 2, the nominal steering angle, which represents the ideal position of the front wheel on path curve 4, is denoted by .sub.d. The ideal nominal position of the front wheel is drawn as a dotted line and is characterized by reference numeral 1.sup.1. Steering angle difference is derived from the difference between actual steering angle .sub.a and nominal steering angle .sub.d. In the case of the understeering in accordance with FIG. 1, steering angle difference is positive; in the case of the oversteering in accordance with FIG. 2, it is negative.

(7) Since the two-wheeled vehicle moves on a path curve 4, it also has an angle of inclination. Ideally, a defined value for the angle of inclination, as well as for the steering angle is associated with a given curve radius and a specific vehicle velocity. In response to a deviation of actual steering angle .sub.a from nominal steering angle .sub.d, the two-wheeled vehicle begins to understeer, respectively oversteer, so that a steering angle difference unequal to zero ensues. To compensate for the understeering, respectively oversteering, the torque currently being applied may be automatically influenced at front wheel 1 and/or rear wheel 2. In the front wheel section, the currently applied braking torque may be modified; in the rear wheel section, the driving torque may be modified by intervening in the engine management; or the braking torque may be modified by intervening in the rear wheel brake. The torques are modified via actuating signals of a regulating, respectively control unit that is incorporated in the two-wheeled vehicle and that generates actuating signals from input signals via which actuators in the engine, respectively in the wheel brakes are adjusted at the front or rear wheel.

(8) FIG. 3 shows a block diagram including the basic functional sequence of the feedback control for stabilizing the two-wheeled vehicle during cornering. A first block 10 represents the sensor system in the motor vehicle that, for example, may be part of a traction-slip control installed in the two-wheeled vehicle and via which the translational and rotational accelerations in all three spatial directions may be ascertained as vehicle state quantities. Moreover, the vehicle velocity, as well as the wheel speeds are to be detected at the front wheel and rear wheel. Moreover, the vehicle is equipped with a sensor system for determining actual steering angle .sub.a.

(9) Another block 11 represents an observer which, on the output side, delivers a nominal steering angle .sub.d that is subtracted from actual steering angle .sub.a in order to ascertain steering angle difference . Steering angle difference is fed as an input quantity to a block 12 that represents a vehicle model to which the measurement signals may be additionally fed as input quantities, for example, vehicle velocity , accelerations a, in particular, the longitudinal acceleration and the transversal acceleration of the vehicle, as well as angle of inclination , that is advantageously not measured, rather may be ascertained from measured quantities.

(10) In vehicle model 12, from steering angle difference , including the operational sign of the steering angle difference, from which a drifting at the rear wheel, respectively understeering at the front wheel may be inferred, a steering-angle controlled variable .sub.k is generated, which, as illustrated in FIG. 4, is fed as an input quantity to a torque controller. Moreover, nominal values are generated as an output variable in vehicle model 12 that are subtracted from corresponding actual values that originate from block 10. The difference is fed as an input quantity to observer 11. The nominal and actual values are, in particular, the vehicle velocity, the angle of inclination and the steering angle.

(11) Moreover, observer 11 may be fed a drift angle tolerance y as an input variable that is considered in the calculation of nominal steering angle .sub.d. Via drift angle tolerance .sub.d, a drift angle, thus, the deviation of the vehicle longitudinal axis from the ideal line, may be allowed, for example, in absolute numbers 1 or 3 in both directions. Via drift angle tolerance , the handling performance may be influenced; a sportier handling performance being selected with increasing drift angle tolerance.

(12) FIG. 4 shows torque controller 13 for adjusting torques M at the front wheel, respectively rear wheel. Torque controller 13 is fed steering-angle correction quantity .sub.k that has been calculated in block 12 (FIG. 3). As further input quantities, correction quantities for the angle of inclination, the drift angle tolerance, correction quantities for accelerations and velocities may be considered, as well as, optionally, a driving mode to be set by the driver, for example, a sporty or comfortable driving mode. Moreover, an allowable drift angle may be preselected that is likewise considered as an input quantity.

(13) Output variable M is an actuating signal that is fed to an actuator in the drive engine of the two-wheeled vehicle or is fed to one of the wheel brakes at the front wheel, respectively the rear wheel for adjustment. Torque controller 13 is advantageously realized in a regulating, respectively control unit which may also include observer 11 and vehicle model 12 of FIG. 3.