Method for determining the lean angle of a two-wheeler

Abstract

A method for determining the lean angle of a two-wheeler in which the axle load on at least one wheel is ascertained and the lean angle is calculated as a function of the axle load.

Claims

1. A method, comprising: ascertaining an axle load on at least one wheel of a two-wheeler; calculating a lean angle as a function of the axle load; and modulating a brake pressure on at least one of a front wheel brake and a rear wheel brake of the two-wheeler as a function of the calculated lean angle.

2. The method as recited in claim 1, wherein the axle load is ascertained at least on a front wheel and is the basis for calculating the lean angle.

3. The method as recited in claim 2, wherein the axle load is ascertained both on the front wheel and on a rear wheel.

4. The method as recited in claim 1, wherein the axle load is ascertained on both a left side and a right side of the wheel.

5. The method as recited in claim 1, wherein a tire pressure on a front wheel and a rear wheel is determined as a function of the axle load.

6. The method as recited in claim 5, wherein a tire pressure check is carried out as a function of the axle load and when the two-wheeler is driven straight ahead.

7. The method as recited in claim 1, wherein, as a function of the axle load, a starting torque and a braking torque is modulated during starting or stopping.

8. The method as recited in claim 1, wherein a vehicle accident system is set in the two-wheeler as a function of the axle load in the case of a vehicle accident.

9. The method as recited in claim 1, wherein an inclination angle is determined as a function of the axle load, and the lean angle is ascertained by adding the inclination angle and a correction angle dependent on a tire width.

10. A regulating or control unit, the regulating or control unit designed to: ascertain an axle load on at least one wheel of a two-wheeler; and calculate a lean angle as a function of the axle load; and modulate a brake pressure on at least one of a front wheel brake and a rear wheel brake of the two-wheeler as a function of the calculated lean angle.

11. A two-wheeler, comprising: a regulating or control unit designed to determine a lean angle of a two-wheeler, the regulating or control unit designed to ascertain an axle load on at least one wheel of the two-wheeler, calculate the lean angle as a function of the axle load, and modulate a brake pressure on at least one of a front wheel brake and a rear wheel brake of the two-wheeler as a function of the calculated lean angle; and a sensor system for ascertaining the axle load on the at least one wheel.

12. The two-wheeler as recited in claim 11, wherein the sensor system includes, on at least one axle, two sensors on a left and a right of the wheel.

13. The two-wheeler as recited in claim 11, wherein the sensor system includes at least one sensor between a wheel axle and a suspension fork which accommodates the vehicle wheel.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 shows a motorcycle in inclined position when negotiating a curve.

(2) FIG. 2 shows the forces and torques acting on the front wheel in the case of an inclined position in the curve and a simultaneously effective brake force.

(3) FIG. 3 shows a front wheel including the suspension on the suspension fork via a bolt including an integrated force sensor.

(4) FIG. 4 shows the bolt including an integrated force sensor in a separate view.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

(5) FIG. 1 shows a motorcycle 1 negotiating a curve. Motorcycle 1 is in an inclined position; inclination angle denotes the angular position between a vehicle center plane 2 and a vertical 3. When motorcycle 1 is in an upright position, vehicle center plane 2 lies in vertical 3.

(6) FIG. 2 shows front wheel 4 in a separate view in an inclined position. Due to the inclined position, tire contact point 6 of tire 4 migrates on roadway 7 from the tire center, through which steering axis 5 passes, to the side of the tire. Tire contact point 6 has distance a to the tire center, the distance forming the disturbing force lever arm. If front wheel 4 is braked, braking force F.sub.br acts on tire contact point 6, which together with disturbing force lever arm a results in a steering disturbance torque M.sub.z of the vertical or steering axis, the steering disturbance torque seeking to upright the motorcycle.

(7) Lean angle represents a driving state variable which is relevant to the vehicle dynamics and which may be used in one or multiple power units or vehicle systems of the motorcycle, in particular in the braking system, in order to automatically adjust the brake pressure and thereby increase the driving safety. Lean angle is ascertained according to
=+

(8) from the sum of inclination angle , which denotes the angular position between vehicle center plane 2 and vertical 3, and a correction angle , which results from the lateral displacement of tire contact point 6 from vehicle center plane 2 to the inside of the curve (displacement a in FIG. 2). Inclination angle may be ascertained according to

(9) $=\arcsin \left[\frac{F_R}{\sqrt{\frac{m^2{v}^2}{r^2}+m^2{g}^2}}\right]+\tan \left(\frac{-v^2}{\mathrm{rg}}\right)$

(10) as a function of total mass m of the motorcycle including the driver and, if necessary, a pillion passenger, curve radius r, motorcycle speed v, gravitational acceleration g and axle load F.sub.R

(11) The calculation rule for inclination angle may, if necessary, be represented as a power series expansion in the regulating or control unit.

(12) Curve radius r may be determined approximately, for example, from the steering angle. In addition or alternatively, it is possible to use map or navigation-based information for ascertaining curve radius r.

(13) Axle load F.sub.R may be determined with the aid of a sensor system. As is apparent from FIG. 3 in conjunction with FIG. 4, the wheel axle of front wheel 4 is coupled via an axle bolt 9 to a suspension fork 8 on the front wheel of the motorcycle, axle bolt 9 (iBolt) including a force sensor which is suitable for measuring axle load F.sub.R acting in vehicle center plane 2. Preferably, an appropriate axle bolt 9 including an integrated force sensor is located on both the left and right suspension fork areas, so that the axle load may be measured on both sides of suspension fork 8. Furthermore, it may also be advantageous to provide an appropriate sensor system on the rear wheel for ascertaining the axle load on the rear wheel, in particular both in the left and right rear wheel areas.