DE102008003079B4 - Method and control device for controlling personal protective equipment for a vehicle - Google Patents

Abstract

Method for controlling personal protection devices (FR) for a vehicle (FZ) with the following method steps: detecting a collision as a function of at least one first signal of an impact sensor (AS), determining a yaw movement by means of a wheel speed sensor (RZ1-4) as a function of - Controlling the personal protection means (FR) in dependence on the yawing motion, characterized in that each second signals of the wheel speed sensors are respectively a vehicle side averaged and resulting average values compared with each other to determine the yawing motion.

Description

State of the art

The invention relates to a method and a control device for controlling personal protection means for a vehicle according to the preamble of the independent claims.

Out DE 10 2006 007 987 A1 It is already known to control rollover protection in dependence on the lateral speed and a slip angle. To determine these dynamic driving variables, among other things, the yaw rate and the wheel speeds determined with the aid of a yaw rate sensor can be used.

From the pamphlets DE 10 2007 017 421 A1 is a method for situation-triggered release of a vehicle restraint system in a vehicle overturning about a vehicle axis oriented in the longitudinal direction of the vehicle known in which a lateral acceleration of the vehicle is measured and compared with a predetermined threshold for the lateral acceleration. If the threshold value is exceeded by the current value for the lateral acceleration, a restraint system is triggered. In addition, a lateral speed of the vehicle is determined from a measured parameter and the threshold value for the lateral acceleration is specified as a function of the determined lateral speed.

From the DE 10 2006 014 008 A1 For example, a method for controlling an active locking system for a belt retractor and an active locking system for a belt retractor are known.

From the DE 10 2005 038 616 A1 a method for driving an active restraint system is known

From the DE 10 2004 062 482 A1 For example, a method and a device for the preventive activation of an occupant protection system are known.

From the DE 44 36 162 C1 For example, a system for controlling the driving stability of a motor vehicle is known. In this case, a control unit evaluates signals from wheel speed sensors, a steering angle sensor, a yaw rate sensor and other sensors. Depending on the evaluation, the control device generates actuating signals with which the brake pressures acting on the individual wheels of the vehicle can be controlled such that the driving state of the motor vehicle remains stable. In addition, the control unit is connected to an airbag control and evaluates the signals of an acceleration sensor of the airbag control.

Disclosure of the invention

The inventive method and the control device according to the invention for controlling personal protection means for a vehicle having the features of the independent claims have the advantage that the yaw motion is determined in a collision by means of the wheel speed sensor, so that the yaw motion is determined robust and reliable. Namely, a yaw rate sensor would be severely impaired in its function in a strong collision collision, so that such a yaw rate sensor would at least temporarily fail to provide reliable results. Here, the yawing motion is now reliably determined in a collision case, so that then personal protection means such as a vehicle dynamics control as active personal protection means or passive personal protection means can be controlled according to the situation.

According to the invention, respective signals of the wheel speed sensor are respectively averaged on one side of the vehicle, and the resulting averages are then compared with each other to determine the yawing motion. The difference or the individual values can also be used to determine the rotational speed etc. It is essential here that the measured wheel speeds are not falsified by ESP braking interventions or the motor drive torque. That it is preferable to take the wheels of a non-driven axle or, at least in the short term, reduce the drive torque and / or suppress ESP interventions. This is possible, for example, in that during or shortly after the collision ESP interventions take place only on the front axle, while the yawing motion is still being determined with the aid of the rear wheels.

Especially in situations with multiple collisions, the method according to the invention or the control unit according to the invention can lead to the mitigation of the consequences of accidents by stabilizing driving interventions. Such interventions can influence the vehicle movement, for example with the aid of active steering systems or wheel-specific braking. This leads to greater safety of the vehicle occupants and reduces the consequences of accidents.

The activation of personal protection means in the present case the activation of such personal protection means as a vehicle dynamics control, a brake, airbags and belt tensioners, crash-active headrests, etc. A vehicle dynamics control such as ESP can intervene by means of various actuators (steering, brake, active suspension).

In the present case, a control device is understood to be an electrical device that transmits sensor signals processed and generated in response to control signals.

The interfaces can be designed in hardware and / or software. In particular, it is possible for the first and second interfaces to form a common interface, for example as part of a so-called system ASIC, which contains various functions for the control unit. The interfaces may also be present on a microcontroller, for example as an evaluation circuit, in the case of a software implementation.

As a first signal of the impact sensor such as an acceleration, an air pressure and / or a structure-borne noise sensor, a single signal, for example, an acceleration signal itself or a signal derived therefrom or even a vector of different individual signals in question. The impact sensor may be distributed at appropriate locations in the vehicle, i. H. For example, concentrated in a sensor control unit or outsourced to the vehicle front or on the vehicle sides. When using a structure-borne noise sensor, suitable couplings to the vehicle chassis are necessary in order to ensure a reliable transmission of structure-borne sound signals from the point of impact to the structure-borne noise sensor system.

The same applies to the second signal as was said for the first signal, wherein the wheel speed sensor system is a conventional sensor system, such as Hall sensors or other inductive concepts.

The evaluation circuit can be implemented in hardware and / or software, with processor types in particular, such as microcontrollers, microprocessors, also being able to be used with more than one processor core. As a hardware embodiment, for example, a so-called ASIC can be used with a fixed program sequence. The collision detection module, the yaw motion detection module and the other modules mentioned in the dependent claims are parts of the evaluation circuit and can also be configured in terms of hardware and / or software.

The control circuit may for example also be like the interfaces parts of the system ASIC or part of the evaluation circuit and also it may be formed in hardware and / or software. Usually, the drive circuit, the interface from the control unit to the outside to the personal protection means, which are located outside the control unit, is.

The yaw movement is understood to mean a rotation about the vertical axis of the vehicle. Usually, the yaw rate or quantities derived therefrom can be determined, for example, with the aid of micromechanical sensors, as used by the ESP.

Also, the switch, which is intended to switch in the event of a collision on the determination of the yaw motion by means of the wheel speed sensor, may be formed in hardware and / or software. In particular, for example, the switch may be configured as an if-then condition, i. H. if a collision occurs, then the yaw motion is determined based on the signals of the wheel speed sensor.

The measures and refinements recited in the dependent claims, advantageous improvements of the specified in the independent patent claims process or control device for controlling personal protective equipment for a vehicle are possible.

It is advantageous that an impact location in dependence on the yawing motion and the first signal, d. H. the signal of the impact sensor is determined, the personal protection means are then controlled in dependence on this impact location. The first signal, for example the signal of an acceleration sensor, indicates on which side the impact, d. H. the collision took place. The yaw movement is used to detect in which direction the vehicle is turning around the vehicle's vertical axis, ie clockwise or counterclockwise. From this it can be estimated in which area the collision took place. This determines which and, if appropriate, how the corresponding personal protection devices are to be controlled. The evaluation circuit has for an impact detection module, which can also be formed in hardware and / or software.

It is furthermore advantageous that a classification of the collision takes place as a function of the signal of the impact sensor and of the yawing motion, wherein the control is carried out as a function of the classification. For the classification, three classes are usually used, the classes being classified, for example, according to the crash types and / or crash severity. The corresponding class then determines whether and which and how strong the personal protective equipment is to be controlled. For this purpose, in turn, the evaluation circuit on a classification module, which may be designed in hardware and / or software.

It is furthermore advantageous that, based on the sign of the signal, the impact sensor is closed in an impact direction and based on a comparison of the wheel speeds in one direction of rotation. The control is then in Dependence on the direction of impact and on the direction of rotation. The direction of rotation can be determined by the fact that the wheels, which are located further outward during the rotational movement compared to the center of rotation, move at a higher wheel speed than the wheels, which are located closer to the center of rotation.

It is furthermore advantageous for the personal protection means, in particular a vehicle dynamics control, to be controlled in order to achieve a mitigation of the accident consequences by stabilizing the vehicle in the event of a collision, in particular in the case of possible multiple collisions.

Embodiments of the invention are illustrated in the drawings and are explained in more detail in the following description.

• 1 ein Blockschaltbild des erfindungsgemäßen Steuergeräts mit angeschlossenen Komponenten im Kraftfahrzeug,
• 2 eine beispielhafte Kollision,
• 3 ein Flussdiagramm des erfindungsgemäßen Verfahrens und
• 4 eine zeitliche Entwicklung der Radgeschwindigkeit bei einer Kollision.

Show it

• 1 a block diagram of the control device according to the invention with connected components in the motor vehicle,
• 2 an exemplary collision,
• 3 a flowchart of the method according to the invention and
• 4 a temporal evolution of the wheel speed in a collision.

1 shows a block diagram of the inventive control device SG with connected components. The control unit SG is arranged in a vehicle FZ. Possible is a central arrangement, for example on the vehicle tunnel, but also other installation locations are possible. The control unit SG has a first interface IF1, which in the present case is designed as an integrated circuit and may preferably be part of a system ASIC. This first interface IF1 is used to connect an impact sensor AS, which is located outside of the control unit SG. The impact sensor AS includes, for example, an acceleration sensor and / or an air pressure sensor and / or a structure-borne sound sensor. An environment sensor is also possible. The transmission of the data, usually digitally from the impact sensor AS to the interface IF1, can take place via a current interface. Also an analog transmission is possible. In this case, a point-to-point and / or bus connection can be used. It is possible that the impact sensor is partly also within the control unit SG, in which case, for example, the microcontroller .mu.C itself has an interface as a software module or else as a hardware module.

Raddrehzahlsensoriken RZ1 to 4 are connected to a second interface IF2. This connection can also be pronounced for example as a CAN connection to a vehicle dynamics control unit, which in turn detects the wheel speeds by means of corresponding sensors. A sensor control device is possible in the present case. It is possible that the wheel speed and / or the speed is transmitted to the interface IS2 as a digital datum. Other derived sizes are possible.

The interface IS1 provides the signal of the impact sensor AS to a collision detection module K on the microcontroller .mu.C as an evaluation circuit. Depending on this signal, the collision detection module determines whether a collision has occurred or not. For this purpose, the technology of a customary evaluation algorithm is used for the activation of personal protective equipment, usually with an adaptive threshold. If a collision is detected by the collision detection module K, then a switch S is actuated, usually a software switch, to activate the yaw motion detection module G. The yaw motion detection module G processes the wheel speed sensor signals provided by the interface IF2. From these signals, the yaw motion detection module determines the parameters characterizing the yaw, such as a yaw rate and the direction of rotation.

With the yaw motion and the collision signal, the impact location is determined in the collision location detection module AO. This impact location enters the control module AN. Furthermore, it is determined in dependence on the yawing motion and the collision signal in the classification module KL, in which class the present collision is to be classified. This class is also transmitted to the control module AN. In this way, the actuation module AN can then determine as the last presently presented module of the microcontroller .mu.C, whether, which and how the corresponding personal protection means are to be controlled. This is then, for example, software and hardware transferred to the drive circuit FLIC, which may also be part of the system ASICs. The drive circuit FLIC then outputs a drive signal to the personal protection device FR, for example a vehicle dynamics control in the present case, in order to stabilize the vehicle accordingly after the collision, so that it is better prepared for follow-up collisions. The drive circuit FLIC is preferably an interface for data transmission, for example, a CAN transceiver or another bus controller when outputting a drive signal for vehicle dynamics control.

The following distribution is possible: The airbag control unit detects the direction of the collision and the corresponding severity of this collision. This data (direction and weight) is transmitted to a vehicle dynamics control unit, which detects the yaw motion based on the wheel speeds. Based on these measurements, vehicle-stabilizing measures are then initiated. It is possible to merge both functions airbag control unit and vehicle dynamics control unit on a control unit.

Consequently, with the aid of the method according to the invention, the direction and optionally the strength of a yawing movement of the vehicle after a collision is determined on the basis of the wheel speed information. As described above, the presence of a collision is first detected with the aid of the impact sensor. If there is a collision, the wheel speeds of the left and right side of the vehicle are compared. If the wheel speeds on the left side increase relative to those on the right side during the collision and immediately thereafter, the collision causes the vehicle to rotate clockwise.

It may be useful for the wheel speed comparison to average the speeds of the front and rear wheels of a page and to compare the averages of both sides.

For the wheel speed comparison, it is also useful to compare the speeds of the wheels of the non-driven axle.

Furthermore, it is useful for wheel speed comparison to suppress wheel speed influencing factors such as drive torques or braking torques during yaw motion detection.

On the basis of the sign of the acceleration measured by the impact sensor, it is possible to distinguish whether the vehicle was hit from the left or from the right.

Together with the information about the evoked direction of the yaw motion can thus be concluded that the location of the impact location.

For example, if the vehicle was struck from the left (negative lateral acceleration) and the yaw rate is also negative (clockwise), then the vehicle was struck in front of the center of gravity.

In 1 a vehicle FZ1 is shown, which is hit in the rear left of another vehicle FZ2 with the speed VK. Due to the forces acting the vehicle FZ1 is struck in a rotation about the vertical axis with the angular velocity Ψ̇. The lateral acceleration ay, which is measured by the impact sensor, is so great that the yaw rate sensor is disturbed in its function and thus can not provide information about the rotation of the vehicle during the collision. The yaw acceleration is negative in the example shown, so that it can be concluded that the vehicle was hit from the left.

Also marked are arrows for the wheel speeds whose length stands for the size of the speed. Due to the counterclockwise rotation, the wheel speeds on the left side of the vehicle are smaller than on the right side of the vehicle, which can be detected by means of the wheel speed sensors of the vehicle dynamics system.

From the fact that the vehicle was struck from the left and that the rotation takes place counterclockwise, it can be concluded by the evaluation circuit μC that the vehicle was struck behind the center of gravity. This information may, for example, be advantageous for the selection of the retaining means to be triggered.

In addition, the determined information about the direction of rotation can be used to perform a stabilizing braking intervention. In the example shown, therefore, immediately after the determination of the direction of rotation, the front right wheel can be selected for a braking intervention which counteracts the yawing motion. A conventional vehicle dynamics system could not perform such an intervention, since the required yaw rate sensor signal is disturbed by the collision forces.

3 shows in a flow chart the inventive method. In the process step 300 a collision is detected on the basis of the signal of the impact sensor system AS, for example by means of a known triggering algorithm for personal protective equipment. Subsequently, in process step 301 then the switch S is actuated to activate the yaw motion detection module so that the yaw motion is determined from this module. The yawing motion is then in the process step 302 determined from the signals of the wheel speeds. In the process step 303 is determined from the collision signal and the yaw movement of the impact location and in the process step 304 From this data, including the impact location, a classification of the collision process is made. In the process step 305 then takes place the control of the personal protection means such as a vehicle dynamics control function of the classification and / or the impact location. Such data as the classification and the yaw movement can also be output, for example, to be used by a vehicle dynamics control unit for driving the vehicle dynamics control.

4 shows in a speed time diagram a typical course for the wheel speed speeds of the two sides of the vehicle. The curve 400 shows the wheels of the right side, and the curve 401 the left side of the vehicle. It can be clearly seen that the left wheels slow down and the right wheels are accelerated. In the area in which there is a clear and measurable difference between the wheel speeds on both sides of the vehicle, the collision forces act. Thus, the direction of rotation of the vehicle is still determined during the action of the collision forces and a targeted initiation of countermeasures such as the control of a vehicle dynamics control possible.

Claims (9)

Method for controlling personal protection devices (FR) for a vehicle (FZ) with the following method steps: detecting a collision as a function of at least one first signal of an impact sensor (AS), determining a yaw movement by means of a wheel speed sensor (RZ1-4) as a function of the collision; - Controlling the personal protection means (FR) as a function of the yawing motion, characterized in that in each case second signals of the wheel speed sensors in each case a vehicle side averaged and resulting average values are compared with each other to determine the yawing motion. Method according to Claim 1 , characterized in that an impact location in dependence on the yawing motion and the at least one first signal is determined, wherein the personal protection means (FR) are controlled as a function of the impact location. Method according to Claim 1 or 2 , characterized in that a classification of the collision takes place in dependence on the first signal and on the yawing movement, wherein the activation is carried out as a function of the classification. Method according to one of the preceding claims, characterized in that reference is made to a direction of rotation on the basis of a sign of the first signal in an impact direction and based on a comparison of the wheel speeds, wherein the control is effected in dependence on the direction of impact and on the direction of rotation. Method according to one of the preceding claims, characterized in that as the personal protection means a vehicle dynamics control (FR) is controlled. Control unit (SG) for activating personal protection means (FR) for a vehicle (FZ), comprising: - a first interface (IF1) providing at least a first signal of an impact sensor (AS), - a second interface (IF2) containing at least one second signal of a wheel speed sensor provides, - an evaluation circuit (.mu.C) with a collision detection module (K), which detects a collision in response to the at least one first signal, with a yawing module (G), which in dependence on the at least one second signal yaw detects, wherein a switch (S) for activating the yawing module (G) is provided, which is actuated in response to the collision, - a driving circuit (FLIC), which in response to the yawing movement drives the personal protection means (FR), characterized in that the evaluation circuit (μC) in each case averages the second signals of the wheel speed sensors on one side of the vehicle u and compare resulting averages to determine the yawing motion. Control unit after Claim 6 , characterized in that the evaluation circuit (.mu.C) comprises an impact detection module (AO), which determines the impact location as a function of the yaw movement and the at least one first signal, so that the drive circuit controls the personal protection means (FR) in dependence on the impact location. Control unit after Claim 6 or 7 characterized in that the evaluation circuit (μC) has a classification module (KL) which classifies the collision as a function of the at least one first signal and the yaw motion, so that the drive circuit (FLIC) depending on the classification, the personal protection means (FR ). Control unit after Claims 6 to 8th , one of the characterized in that the drive circuit (FLIC) outputs a drive signal for a vehicle dynamics control as the personal protection means (FR).

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