EP2714479A1

EP2714479A1 - Inclination-dependent adaptation of brake force regulation in single-tracked vehicles

Info

Publication number: EP2714479A1
Application number: EP12713067.2A
Authority: EP
Inventors: Christian Groeger; Markus Lemejda; Anja Wahl; Peter Ziegler
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2011-05-27
Filing date: 2012-03-28
Publication date: 2014-04-09
Also published as: WO2012163567A1; TW201304988A; TWI583580B

Abstract

The invention relates to a method for brake regulation in a single-tracked vehicle equipped with a front wheel brake and a rear wheel brake, in which method the presence of a rider braking intervention at a first wheel is determined and, if a rider braking intervention is present, a rider-independent braking intervention is performed at the second wheel. The essence of the invention consists in that the rider-independent braking intervention is dependent on the sideward inclination of the motor vehicle.

Description

description

title

Slope-dependent adaptation of a brake force control in single-track vehicles

State of the art

From DE 10 2007 019 039 AI a method for controlling the

Brake pressure in motorcycles known. This one has among others one

Integral brake on, in which the brake of the second brake circuit is additionally braked when the hand brake lever or the foot brake lever.

From DE 42 44 112 C2 an anti-lock control system for motorcycles is known. In this case, the angle of inclination of the motorcycle is determined and, if this angle exceeds a critical threshold, the brake pressure at the front wheel is limited to a value which is smaller than the expected blocking pressure.

The features of the preambles of the independent claims are taken from DE 10 2007 019 039 AI.

Disclosure of the invention

The invention relates to a method for brake control in a single-track vehicle equipped with a front brake and a rear wheel brake, in particular a motor vehicle or motorcycle, in which the presence of a driver brake intervention or driver-dependent braking intervention on a first wheel is determined and in the event of a driver brake intervention driver-independent braking intervention on the second wheel is performed. The essence of the invention is characterized in that the driver independent

Brake intervention on the second wheel depending on the lateral inclination of the

Motor vehicle is. The first wheel is either the front wheel or the rear wheel, the second wheel the other wheel.

With increasing lateral inclination of a single-track motor vehicle, an increasing cornering force is required to prevent lateral sliding of the motor vehicle. This in turn means that less actionable longitudinal deceleration force is available for a braking operation. Therefore, it makes sense to consider the lateral inclination in a driver-independent braking intervention.

An advantageous embodiment of the invention is characterized in that the presence of a driver-dependent braking intervention on the front wheel is determined and in its presence takes place depending on the side inclination angle of the single-lane vehicle driver independent braking intervention on the rear wheel. Since the braking of the front wheel builds up a steering torque on the front wheel, it is advantageous to leave the braking of this wheel to the driver and brak the rear independently of the driver in a suitable manner.

An advantageous embodiment of the invention is characterized in that the intensity of the driver-independent brake engagement on the second wheel, which is in particular the rear wheel, depends on the lateral inclination, that with increasing side tilt angle a brake engagement of lower intensity or braking force or lower brake pressure is performed in the wheel brake , With increasing side tilt angle becomes an increasing

Cornering force needed. Therefore, a brake engagement acting in the vehicle longitudinal direction should only be of lesser intensity or braking force

be performed.

An advantageous embodiment of the invention is characterized in that the intensity of the driver-independent brake engagement on the second wheel so depends on the side slope that with increasing side tilt angle or when exceeding a threshold value by the side tilt angle the threshold value of an anti-lock braking system acting on the second wheel is reduced and / or the gradient for the braking force build-up following a braking force reduction is reduced during an antilock control taking place on the second wheel.

The increase in sensitivity of the anti-lock control system (ABS) ensures that even at relatively low brake pressure values, the ABS control becomes active. As a result, the pressure build-up and shutdown caused by the ABS control takes place only in the range of relatively small pressure values and no strong pressure fluctuations can occur.

The braking interventions on the first wheel can both independently of

Side tilt angle of the motor vehicle as well as depending on it. In the first case, i. the braking intervention on the first wheel is independent of

Side tilt angle of the motor vehicle, is advantageously given the driver full control of the first wheel. In the second case, i. of the

Brake intervention on the first wheel is dependent on the side tilt angle of the motor vehicle, the speed of the pressure build-up is advantageously limited depending on the side tilt angle to ensure greater lateral force in the initial phase of braking and to prevent the onset of ABS control on the first wheel. The braking intervention on the first wheel is therefore no longer determined solely by the driver's default in the second case, but in addition there is also the side tilt angle in the applied braking force.

An advantageous embodiment of the invention is characterized in that

that depending on the lateral inclination of the motor vehicle for the second wheel a maximum, deductible in the vehicle longitudinal direction tire force is determined, and

Depending on the determined maximum deductible tire force in the vehicle longitudinal direction, the intensity of the braking on the second wheel is adjusted independently of the driver. An advantageous embodiment of the invention is characterized in that the maximum deductible in the vehicle longitudinal direction tire force according to the relationship

Fx max = = mr · g ·

where Fxmax denotes the maximum tire force settable in the vehicle longitudinal direction, mr denotes the mass supported by the second wheel, g denotes the earth gravitational constant, μ denotes the assumed, estimated or determined coefficient of friction between the tire and the roadway and .alpha. Motor vehicle features.

An advantageous embodiment of the invention is characterized in that the braking intervention by means of a hydraulic brake system is performed and that the intensity of the braking engagement is determined by the hydraulic pressure in a wheel brake cylinder.

An advantageous embodiment of the invention is characterized in that the presence of a driver-dependent braking engagement on the rear wheel is determined and in the presence of a dependent on the lateral inclination angle of the single-lane vehicle driver independent braking intervention takes place on the front wheel, the steepness or rapidity of the intensity build-up of the braking force and the temporal gradient the braking force build-up or the brake pressure build-up on the front wheel is dependent on the lateral inclination angle of the single-track vehicle.

Furthermore, the invention comprises a control device, comprising means which are designed to carry out the above-mentioned methods.

The drawing comprises the figures 1 to 3.

Fig. 1 shows a schematic representation of an inclined motorcycle with marked inclination angle.

Fig. 2 shows the comb ^' see circle with the forces essential to the invention. Fig. 3 shows the basic sequence of the method according to the invention.

The present invention provides a way to prevent that when performed by the driver front wheel braking of the rear wheel by means of the integral brake function additionally built rear brake pressure is so great that the rear wheel is significantly overbrake in a curve situation and gets into a strong ABS control. A strong ABS control would have the consequence that the rear brake pressure fluctuates greatly, so that the deceleration of the motorcycle and in particular the cornering force of the rear wheel varies greatly. As a result, the driver may be frightened and possibly slow down or reduce the banking angle, resulting in an increase in the radius of curvature. Both are in a dangerous situation, in which the braking distance should be minimal to avoid.

The object of the invention is to use the

Slope angle or a comparable signal and optionally in addition to the wheel speeds to adjust the strength of an integral brake or ABS control so that still as large as possible

Delay effect is achieved, but without causing strong pressure fluctuations in the wheel brake cylinder or braking force fluctuations. As a result, the driver is not insecure and can continue to delay as much as possible in a safety-critical situation and keep his lane.

With the help of the skew value and the current deceleration, as well as assuming a coefficient of friction for the friction pair road tires, a total mass of the motorcycle and a mass distribution can be determined which longitudinal force potential is available at the rear wheel. This can, possibly provided with a safety margin, be used as an upper limit for a possible driver-independent braking intervention on the rear wheel

For example, the required during cornering lateral force of

Motorcycle tire are calculated as follows: Fy = mr -g · tan (a), where mr is the mass acting on the motorcycle tire, g is the earth's gravity, and α is the measured or estimated banking angle of the motorcycle. The angle α is the angle between the perpendicular to the road and the vertical axis of the motorcycle, ie for a non-inclined

Motorcycle is α = 0 and for a laterally overturned motorcycle is α ~ 90 °.

Fy is the side force or lateral force which must be applied or compensated by the tire for lateral guidance. The skew angle α is the inclination angle of the motorcycle and in Fig.l drawn. There, 100 denotes the carriageway, 101 a schematic representation of the inclined motorcycle, 102 the vertical to the carriageway and 103 the vertical axis of the motorcycle. Assuming a comb ^'rule applies friction circle

Fxmax = max -Fy = ^{mr ■ § ■} ^ ² -tan ² («)

Here, Fmax is the maximum deductible force corresponding to the radius of the crest ^'rule friction circle and is obtained according to the equation

Fmax = mr -g.m.

The total directional force Fmax is the vectorial sum of the transversal force Fy and the longitudinal force Fxmax. μ is the coefficient of friction between the tire and the road surface, mr is the mass supported by the driver-independently braked wheel, in particular the mass supported by the rear wheel. The entire mass of the motorcycle is supported by the front wheel and the rear wheel, and mr is the mass fraction supported by the rear wheel.

The comb ^'sche circuit is also shown in Fig. 2. The horizontal abscissa indicated by y represents the transverse direction to the motorcycle which moves in the vertical ordinate direction indicated by x. The circle radius denoted by Fmax corresponds to the maximum deductible force between the tire and the roadway, which in particular depends on the coefficient of friction μ and the Weight depends on which the tire is pressed onto the road. This weight corresponds to the tire-supported mass fraction mr of the motorcycle. This maximum deductible force Fmax must be partly applied as force Fy for the necessary, dependent on the inclination angle side guide, partly as a longitudinal force Fxmax for the deceleration (or the acceleration) of the motorcycle available.

With such an estimate for Fxmax, the known wheel radius and an estimate of the coefficient of friction of the brake, the maximum allowable brake pressure can be calculated, which is still without brake during braking

Pressure modulation is possible. This value can be used as the upper limit for active pressure build-up by the integral brake function to achieve stable wheel behavior.

In an alternative embodiment, a map can be stored in the control unit, which determines the brake pressure to be set at the rear wheel as a function of the pressure which the driver feeds on the front wheel and the banking angle. This map can be adjusted in the driving test so that the best possible compromise between deceleration of the motorcycle and the rest of the motorcycle when braking at different inclinations and different rider priorities is found.

In a further alternative embodiment, instead of a

tilt-dependent braking pressure specification on the rear axle, the ABS control on the rear axle are made more sensitive. The ABS-Anregelschwellen are often very good for the rear wheel of the motorcycle

set insensitive, as a slightly overbrake rear wheel at

Driving straight ahead is usually not a danger. If the ABS control thresholds for the rear wheel are now changed as a function of the angle,

in particular, a small starting slip and a shallower

Pressure build-up gradient set on steep slopes, then automatically too high, driver-independent pressure specifications would be on

limited driving dynamics meaningful values, because the ABS controller of the

Integral brake function is superimposed. By the mentioned small

Anregelschlupf finds even at relatively low pressures an ABS control instead, which is hardly noticeable for the driver because of the small pressure values. Also, the pressure build-up following the pressure build-up within the scope of the ABS control takes place more slowly than with an ABS control when there is a steep incline.

A generalization of the described invention is possible in that not only the active pressure build-up on the rear wheel in driver operation of the

Front wheel brake is adjusted during cornering, but also a possible pressure build-up on the front wheel when the rear brake is operated by the driver. Here must be avoided in particular that the pressure build-up on the front wheel is too fast, because otherwise the driver has to build very quickly a counter-steering torque on the handlebar to the by the

Front brake intervention to compensate for resulting steering brake torque.

Therefore, here is a gradient-limited structure of the brake pressure on

Adjust the front wheel depending on the inclination.

The basic sequence of an embodiment of the invention

Method is shown in Fig. 3. After starting the method in block 300, the angle of inclination α of the motorcycle is determined in block 301. In block 302 it is then queried whether the driver brakes the front wheel. The

Front wheel braking is done by the driver usually by operating a hand lever, the rear wheel brake is usually by pressing a

Foot lever executed. In the case of an actuated front brake (indicated by branch "y"), the rear wheel is braked in a tilt-dependent manner without the driver's intervention in block 303. Thereafter, the method ends in block 304. If no operation of the front brake is detected (by branch "n")

flag), then immediately go to the end of the process in block 304.

Claims

claims

1. A method for brake control in a vehicle equipped with a front brake and a rear wheel single-track vehicle, in particular a motor vehicle, in which the presence of a driver's braking intervention on a first wheel is determined (302) and in the present driver brake intervention, a driver-independent braking intervention on the second wheel is performed (303 ), characterized in that the driver-independent braking intervention is dependent on the lateral inclination (a) of the motor vehicle.

2. The method according to claim 1, characterized in that the presence of a driver-dependent braking intervention on the front wheel is determined (302) and in the presence of a dependent on the lateral inclination angle (a) of the vehicle driver independent braking intervention takes place at the rear wheel (303).

3. The method according to claim 1, characterized in that the intensity of the driver-independent brake engagement on the second wheel of the

Side tilt depends that with increasing side tilt angle (a) a brake intervention of lesser intensity is performed.

4. The method according to claim 1, characterized in that the intensity of the driver-independent brake engagement on the second wheel of the

Lateral inclination (a) depends on the fact that with increasing lateral tilt angle (a) or when a threshold value is exceeded by the lateral inclination angle (a)

- The threshold value of an anti-lock brake system is reduced and / or

- That the gradient is reduced for the braking force build-up following an anti-lock control.

5. The method according to claim 1, characterized in that the intensity of the brake engagement on the first wheel is independent of the lateral inclination angle (a) of the motor vehicle.

6. The method according to claim 1, characterized in that the intensity of the brake engagement on the first wheel is dependent on the lateral inclination angle (a) of the motor vehicle, wherein in particular the speed of the pressure build-up depends on the lateral tilt angle (a).

7. The method according to claim 1, characterized

- That depending on the lateral inclination (a) of the vehicle for the second wheel, a maximum deductible in the vehicle longitudinal direction tire force is determined, and

- Depending on the determined maximum deductible in the vehicle longitudinal direction tire force (Fxmax) the intensity of the braking on the second wheel

independent of the driver.

8. The method according to claim 7, characterized in that the maximum deductible in the vehicle longitudinal direction tire force according to the relationship

Fxmax = mr · g ·

where Fxmax denotes the maximum tire force settling in the vehicle longitudinal direction, mr denotes the mass supported by the second wheel, g denotes the earth gravitational constant, μ den

assumed, estimated or determined friction value between the tire and the road surface and α denotes the lateral inclination angle of the vehicle.

9. The method according to claim 1, characterized in that the braking intervention by means of a hydraulic brake system is performed and that the intensity of the braking engagement by the hydraulic pressure in a

Wheel brake cylinder is determined.

10. The method according to claim 1, characterized in that the presence of a driver-dependent braking engagement on the rear wheel is determined and in the presence of a side tilt angle (a) of the single-lane vehicle dependent driver-independent braking intervention takes place on the front wheel, said Steepness or speed of the intensity build-up of the braking force on the front wheel is dependent on the lateral inclination angle (a) of the single-track vehicle.

11. Control device containing means which are designed to carry out the above-mentioned method.