WO2006077211A1

WO2006077211A1 - Method and device for regulating the braking force and/or driving force of a two-wheeled vehicle

Info

Publication number: WO2006077211A1
Application number: PCT/EP2006/050248
Authority: WO
Inventors: Frank Steinmeier; Joachim Scholer; Karl-Heinz Hennemann; Otmar Simon; Hans Georg Ihrig
Original assignee: Continental Teves Ag & Co. Ohg
Priority date: 2005-01-21
Filing date: 2006-01-17
Publication date: 2006-07-27
Also published as: DE102006002399A1

Abstract

Disclosed is a method for regulating the braking force and/or driving force of a two-wheeled vehicle such as a motorcycle. According to said method, the rotating behavior of the vehicle wheels is determined by measuring the rotational speed while inclined positions of the vehicle are determined by measuring accelerations, and said rotating behavior and inclined positions are used for determining the controlled variables for a regulating intervention when the cruising stability is jeopardized. The inventive method is characterized in that the acceleration components that affect the vehicle are determined according to the amount and the direction thereof by measuring the acceleration at several predefined points of the vehicle and in several predefined directions, and said data is evaluated in order to determine the forces and force components that are applied to the contact surface of the vehicle tires in the x, y, and z direction, x representing the longitudinal direction, z representing the vertical axis, and y representing the axis that runs perpendicular to x and z, and recognize the angular position of the vehicle (angle of tilt λ, pitch angle ϕ) and/or the travel situation (e.g. lifting of a wheel, riding over a hump, etc.). A device for carrying out the disclosed method comprises a combined acceleration sensor (KBS) that is composed of four sensor elements which are disposed in a specific alignment along the longitudinal axis and the transversal axis of the vehicle.

Description

Method and device for controlling the braking and / or driving forces of a single-track vehicle

The present invention relates to a method for controlling the braking and / or driving forces of a single-track vehicle, in particular a motorcycle. In this method, the rotational behavior of the vehicle wheels and by acceleration measurements on the vehicle vehicle inclinations are determined by wheel speed measurement and used to determine the control variables for a control intervention. Devices for carrying out the method likewise belong to the invention.

A method of this type is already known from German Patent DE 42 44 112 C2. It is in principle a standard anti-lock control system (ABS), in which the information for detecting blocking tendencies and for regulating and limiting the brake slip are obtained in a known manner by means of wheel speed sensors. In addition, two stationary on the vehicle arranged acceleration sensors are available from the output signals, a skew angle of the single-track vehicle, namely the motorcycle, can be calculated. The skew in the curve Motorcycles are known to have a major influence on the driving stability of the vehicle and should therefore be taken into account in the regulation. Obtaining sufficient cornering power while cornering is essential in motorcycles for understandable reasons; in a multi-lane vehicle (four-wheel vehicle), the cornering force of the wheels in critical situations is less critical.

For a traction control (ASR or TCS) applies in principle the same.

From the German patent application DE 102 32 362 Al it is known to stabilize the cornering of a single-track vehicle, which is equipped with a regulated brake system (ABS), one or two lateral acceleration sensors and optionally provide an additional yaw rate sensor on the vehicle. The lateral acceleration sensors are used to detect cornering. The output signals of these lateral acceleration sensors are then used to a corresponding reduction of the braking torque in the curve.

The design of the braking force to stabilize the cornering of a single-lane vehicle is of course not solely dependent on the current lateral acceleration of the vehicle, especially since too high a braking torque in the curve may be taken as little in purchasing, such as too high a reduction of the braking torque, the one would cause unnecessarily long braking distance.

The present invention is therefore an object of the invention to develop a method with which the brake pressure or The braking torque can be determined and set in different situations - cornering, straight ahead, high or low coefficient of friction, driving over hills, etc. - leads to a (nearly) optimal braking while maintaining the driving stability.

It has been found that this object can be achieved by the method described in claim 1, whose peculiarity is that the acceleration components occurring at the vehicle on the basis of magnitude and direction are determined by acceleration measurements at several predetermined locations of the vehicle and in several predefined directions that this information for the determination of the contact surfaces of the vehicle wheels or. tire occurring forces and force components in the x-, y- and z-direction (x = longitudinal direction, z = vertical axis, y = axis perpendicular to x and z) and to detect the angular position of the vehicle (banking angle, pitch angle) and / or the driving situation (eg lifting a wheel, dome driving etc.

In this way, the influencing variables relevant for driving stability are recorded directly.

According to an advantageous exemplary embodiment of the invention, on the basis of a mathematical vehicle model for single-lane vehicles, the contact surfaces of the vehicle wheels or vehicle wheels are replaced by a vehicle. tire occurring forces and force components in the x-, y- and z-direction determined from the acceleration components measured on the vehicle.

Furthermore, it has proved to be particularly favorable to use the accelerator components with the aid of individual sensor elements. to be measured, which are arranged in pairs on the longitudinal axis of the vehicle and on the transverse axis of the vehicle at a predetermined angle to each other and / or to an axis of the vehicle such that by correlation and evaluation of the sensor signals information about the acceleration of the vehicle in x , y and z direction.

An apparatus for carrying out the method according to the invention, which is described in appended claim 7, includes wheel speed sensors, an acceleration measuring system with a plurality of acceleration sensors fixed to the vehicle, an electronically controllable wheel brake system and a vehicle computer system for evaluating the sensor signals and generating or influencing the brake drive signals. The acceleration measuring system has a plurality of acceleration sensor elements, which are arranged at a predetermined angle to each other and / or to the vertical axis of the vehicle such that with the help of the entirety of the acceleration sensor elements information about the acceleration of the vehicle in the x-, y- and z-direction of the vehicle is available. This information is inventively in the vehicle computer system for determining the forces and force components occurring in the footprints of the vehicle wheels or tires in the x-, y- and z-direction and for determining the angular position of the vehicle, in particular the skew and the pitch angle, and other dynamic driving Sizes evaluated.

In the appended subclaims, other advantageous embodiments of the method and apparatus according to the invention are mentioned. Other features, advantages and applications of the invention will become apparent from the following description of the details and the explanation of the operation by means of embodiments of the invention.

The attached figures serve to illustrate the operation of the invention. It show in symbolic representation

Fig. 1 shows a side view of a single-track vehicle and the arrangement and orientation of the sensor elements,

Fig. 2 in the same representation as Fig. 1 is a rear view of the vehicle of FIG. 1, and

Fig. 3 is a flow chart of an example method.

The requirements for single-lane vehicles with regard to driving stability are generally far higher than the requirements for a car. So z. B. slipping wheels when cornering to a slipping and thus lead to the fall. At high wheel slip is known, the cornering force of a wheel is very low. Braking torques in the curve cause an additional steering torque due to the wheel contact point shifted to the center of the curve, which leads to a deviation from the driver's intention course. In addition, strong pressure modulations generate changing steering moments that lead to instabilities.

In single-track vehicles, in spite of ABS or ASR (TCS) z. B. the driving situations listed below lead to a fall under unfavorable conditions: - braked angle

- accelerated inclination

- Brakes in compression

- Brakes over crests

- accelerate over crests

- Brakes with lifting rear wheel

- Accelerate with lifting front wheel

Remedy the inventive method. By evaluating the information obtained with the aid of the additional acceleration measuring system and the wheel or tire contact forces derived therefrom, it is possible to optimize the brake pressure or braking force course by appropriate design of the brake force control system (ABS, ASR) for these driving conditions as well.

An apparatus for carrying out the method according to the invention consists in the embodiments described here of the typical elements of a standard ABS system for a single-track vehicle:

• two wheel speed sensors

• Pressure, force or displacement sensors for detecting the driver's brake request using systems with foot and / or hand brake levers or integral brakes

• individually or combined controllable wheel brakes

• Hydraulic unit for controlling the wheel brakes (HCU); alternatively, an electric or electro-hydraulic brake actuation system may be used

• vehicle computer system (ECU) In addition, according to the invention

• a combination acceleration sensor (KBS) and

• an extended evaluation logic for the determination and evaluation of the wheel contact forces

used.

The invention is thus based on the knowledge that

(a) a decisive improvement in the control can be achieved if the forces in the x-, y- and z-direction are known at the footprints of the wheels or tires, and that

(B) only by means of wheel speed sensor the exact evaluation of the forces is not possible, which is why an additional sensor must be used.

It is also required that

(c) an additional sensor system for single-track vehicles due to the limited installation space must have small dimensions, and that

(D) for the additional sensors a comparatively low production cost should be sufficient.

Considering the above points, an essential feature of the invention is the "intelligent" combination of four acceleration sensor elements to a combination acceleration sensor (called KBS) Basis for a method and a device for the acquisition of measured values or data that are required for optimal braking force and / or driving force control.

The combination acceleration sensor KBS in the present exemplary embodiment of the invention consists of four individual acceleration sensor elements which are arranged at a specific angle to one another and to the vehicle axles. As FIGS. 1 and 2 illustrate, two sensor elements (FIG. 1) lie on the longitudinal axis and two sensor elements (FIG. 2) on the transverse axis of the vehicle. This arrangement makes it possible to precisely determine the forces and angles of a single-track vehicle and to unequivocally decompose these into x, y and z forces on the wheel contact surfaces on the basis of a mathematical vehicle model.

In addition, in FIGS. 1 and 2, the center of gravity sp of the vehicle is indicated. VA is the front wheel, HA the rear wheel of the vehicle. KBS is the combination acceleration sensor, the measuring directions of the individual sensor elements are shown with obliquely upward-pointing arrows and the acceleration components a1, a2 and a3, a4 are measured in the indicated measuring directions. The angle to the vertical axis h in the exemplary embodiment described here is in each case 45 °. The roadway is marked in Figures 1 and 2 by a wider horizontal line.

The footprint of the vehicle wheels or tires VA and HA on the roadway represented by a wide black ring depends inter alia on the vehicle's banking angle when driving on a curve. In Fig. 2 is based on a straight ahead. The operation of the method and the device according to the invention can be summarized as follows:

The combination acceleration sensor KBS offers the possibility of determining the forces at the wheel contact surfaces in the x-, y- and z-direction via trigonometric functions.

For this purpose, it uses the signals (a1, a2, a3, a4) from four acceleration sensors or acceleration sensor elements that lie in a special arrangement relative to one another.

The two sensor elements (see FIG. 1) lying on the longitudinal axis (in a plane parallel to the longitudinal and vertical axes of the vehicle, that is to say in an xz plane) are at an angle α 1, α 2 (in the exemplary embodiment approximately every 45 °) °) to the vertical axis h (z-axis) of the vehicle. They measure the accelerations a1, a2 in the directions indicated by the arrows and thus reproduce the acceleration components in the x and z directions with reference to a vehicle-fixed coordinate system.

From the angle relationships can be the following

Acceleration components and fahrdynamichen sizes are determined: a) the longitudinal acceleration a _x in the x direction b) the normal acceleration a _z in the z direction c) the pitch angle φ of the vehicle

For example, the relationship applies to the normal acceleration in a vehicle-fixed coordinate system: a _z = (al - sin (αl) + a2 ^• cos (α2)) / 2

For a terrestrial coordinate system, the relationship is:

a _z = (al - sin (αl - φ) + a2 ^• cos (α2 + φ)) / 2

The two sensor elements lying on the transverse axis (in a plane perpendicular to the longitudinal axis of the vehicle, that is to say in a yz plane) (see FIG. 2) are at an angle α3, α4 (in the exemplary embodiment likewise approximately 45 ° in each case) arranged to the vertical axis of the vehicle. They measure the accelerations a3, a4 in the directions indicated by the arrows and represent the acceleration components in the y- and in the z-direction relative to a vehicle-fixed coordinate system.

From the angular relationships a) the lateral acceleration a _y in the y direction b) the normal acceleration a _z in the z direction c) the banking angle λ of the vehicle can be derived.

The following signals are now available for further calculation, which are specified in a vehicle-fixed coordinate system:

the longitudinal acceleration a _x in the x direction, the transverse acceleration a _y in the y direction

the normal acceleration a _z in the z-direction (twice in the plausibility of the signals)

In addition, the pitch angle φ of the vehicle and the banking angle λ of the vehicle known .

From the accelerations acting on the combination acceleration sensor KBS, the forces on the vehicle wheels or tires can now be calculated according to size and direction. For this purpose, the vehicle data, z. B. Position of the center of gravity sp and total mass m, needed as parameters and several mathematical equations. Consider the total balance of forces of the vehicle and form the sum of the moments around the tire contact surfaces. Since no moments can attack in the tire uprising, the equations are to be resolved according to the forces at the tire erection point.

You get :

At the front axle

- the longitudinal force Fx-VA the lateral force Fy-VA the normal force Fz-VA

At the rear axle the longitudinal force Fx-HA the lateral force Fy-HA the normal force Fz-HA

In addition, you can determine:

- The pitch angle φ of the vehicle

- The banking angle λ of the vehicle

By means of the relations from the Kamm circle, the brake or brake can now be used. Acceleration forces are optimized. The aforementioned information obtained with the aid of the combination acceleration sensor KBS according to the invention is included in a variety of ways in the control algorithm of the control system (ABS, ASR, etc.), which finally results in a much better, more accurate, compared to the conventional control systems without KBS Depending on the driving situation, adapted control can be achieved. Among others, z. B. the control intervention thresholds of the ABS, the maximum permissible brake pressure at the front wheel VA and at the rear wheel HA and further control variables depending on the actual occurring tire contact forces determined in the j eweiligen situation, in addition, the inclination of the vehicle and other driving dynamics influencing variables (driving over crests , lifting wheel etc.) can be included in the calculations.

In one embodiment of the invention, specific brake pressure limits have been defined individually for the front wheel VA and the rear wheel HA of the vehicle for the following situations:

- braked angle,

- brakes with lifting rear wheel,

- Brakes over crests.

According to another embodiment apply special brake pressure limits for the permissible drive torque at

- accelerated inclination,

- when accelerating with lifting front wheel,

- when accelerating over crests. Further examples of interventions in the ABS control as a function of the information obtained according to the invention are:

Setting a maximum gradient for the increase of the brake pressure at a braked angle, adapting the wheel speeds to the detected angle,

Increase the maximum allowable deceleration when braking in compression,

Optimization of the brake force distribution to the front and rear wheel as a function of the braking process, and

- Optimization of the thresholds and limits by combining the aforementioned measures depending on the findings of the invention on the peculiarities of j eweiligen driving situation.

In Fig. 3, a flowchart of an example method is shown schematically. Block 1 represents the combination acceleration sensor KBS, which consists of four individual acceleration sensor elements which are mounted in a known mounting position in the vehicle, d. H . the position and position of the sensor elements in the vehicle-fixed coordinate system are known. The sensor elements measure the accelerations al, a2, a3, a4 in known directions.

On the one hand, the accelerations a _x , a _y , a _z (block 3), which act on the vehicle in the x, y and z directions, are determined by means of a calculation algorithm 2 from the data measured by the acceleration sensor elements. By another calculation algorithm 4, the forces on the wheel contact surfaces Fx-VA, Fy-VA, Fz-VA, Fx-HA, Fy-HA, Fz-HA (Block 5). In this case, the center of gravity sp and the total mass m (block 6), which is estimated and / or by other sensors, such. B. Seat detection sensor and / or compression travel in the state, can be determined.

On the other hand, the pitch angle φ and the skew angle λ (roll angle) are calculated by means of a calculation algorithm 7 from the mutual overlaying / supplementing of the measured data of the sensors (block 8).

Since the system is overdetermined by the four sensors, the measured data of the four sensor elements for redundancies, sensor balances and / or failsafe concepts can be used by means of a calculation algorithm 9 (block 10). If there are any discrepancies, a warning can be issued to the driver, which alerts the driver to a possible problem, eg. B. a warning lamp 12 can be activated.

The information and data from the blocks 5, 8 and 10 are used to increase driving safety by adapting brake pressure and / or drive torque to the driving situation (block 13). The modulation of brake pressure and / or drive torque may, for. B. be made through the existing ABS system.

Claims

Claims:

1. A method for controlling the braking and / or driving forces of a single-track vehicle, in particular a motorcycle, determined by the wheel speed measurement, the rotational behavior of the vehicle wheels and by acceleration measurements on the vehicle vehicle inclinations and used to determine the control variables for a control intervention, characterized in that the acceleration components occurring at the vehicle on the basis of magnitude and direction are determined by acceleration measurements at a plurality of predefined locations of the vehicle and in a plurality of predetermined directions, and that this information is used to determine the contact surfaces of the vehicle wheels or vehicle wheels. tire occurring forces and force components in the x-, y- and z-direction (x = longitudinal direction, z = vertical axis, y = axis perpendicular to x and z) and for detecting the angular position of the vehicle, in particular the inclination angle (λ) and of the pitch angle (φ), and / or the driving situation are evaluated.

2. The method according to claim 1, characterized in that the contact surfaces of the vehicle wheels or. tire occurring forces and force components in the x-, y- and z-direction based on a mathematical vehicle model for single-track vehicles from the acceleration components measured on the vehicle (al, a2, a3, a4) are determined.

3. The method according to claim 1 or 2, characterized in that the acceleration components (al, a2, a3, a4) are measured by means of individual sensor elements, the in each case in pairs on the longitudinal axis of the vehicle and on the transverse axis of the vehicle at a predetermined angle to each other and / or to an axis of the vehicle are arranged such that by correlation and evaluation of the sensor signals information about the acceleration of the vehicle in x, y and z direction (x = longitudinal direction of the vehicle, z = vertical axis of the vehicle, y = axis perpendicular to x and z) is obtained.

4. The method according to claim 3, characterized in that the measuring directions of the two sensor elements of a pair of sensors are in each case arranged at an angle of approximately 45 ° to the vertical axis of the vehicle.

5. The method according to claim 3 or 4, characterized in that by evaluating the measured values (al, a2) of the two arranged on the longitudinal axis of the vehicle sensor elements, the acceleration components are determined in the x and z direction of the vehicle.

6. The method according to one or more of claims 3 to 5, characterized in that by evaluating the measured values (a3, a4) of the two sensor elements arranged on the transverse axis of the vehicle, the acceleration components are determined in the y- and z-direction of the vehicle.

7. Apparatus for carrying out the method according to one or more of claims 1 to 6, with wheel speed sensors for determining the rotational behavior of the vehicle wheels, with a fixedly mounted on the vehicle, several acceleration sensors containing accelerometer, with an electronically controlled RadbremsSystem and with a vehicle computer system (ECU) for evaluating the sensor signals and for generating or influencing the Bremsenansteuersignale, characterized in that the acceleration measuring system comprises a plurality of acceleration sensor elements which are arranged at a predetermined angle to each other and / or to the vertical axis of the vehicle such that by means of Acceleration sensor elements overall information about the acceleration of the vehicle in the x-, y- and z-direction (x = longitudinal direction of the vehicle, z = vertical axis of the vehicle, y = axis perpendicular to x and z) is available, in the vehicle computer system ( ECU) for determining the forces and force components in the x-, y- and z-direction occurring at the footprints of the vehicle wheels or tires and for determining the angular position of the vehicle, in particular the banking angle (λ) and the pitch angle (φ), and others vehicle dynamics variables can be evaluated.

8. The device according to claim 7, characterized in that the acceleration measuring system in the form of a combination acceleration sensor (KBS) is formed, comprising four sensor elements, of which two sensor elements are arranged on the longitudinal axis and two sensor elements on the transverse axis of the vehicle each of the two sensor element on the longitudinal and the transverse axis at a certain angle to each other and to the vertical axis of the vehicle, preferably at an angle of about 45 ° to the vertical axis (z-axis) are arranged.