WO2005063514A1

WO2005063514A1 - System and method for the anti-roll stabilisation of a motor vehicle, in particular of buses, transporters, off-road vehicles or similar

Info

Publication number: WO2005063514A1
Application number: PCT/EP2004/013804
Authority: WO
Inventors: Wolf Boll
Original assignee: Daimlerchrysler Ag
Priority date: 2003-12-20
Filing date: 2004-12-04
Publication date: 2005-07-14

Abstract

The invention relates to a system for the anti-roll stabilisation of a motor vehicle, in particular of buses, transporters, off-road vehicles or similar. Said system comprises: at least one transversal acceleration sensor (2), located in the roof region of the motor vehicle (1), for detecting a transversal acceleration that acts on the motor vehicle (1); a control unit (3), which is connected to the transversal acceleration sensor (2), for receiving the detected transversal acceleration data; and at least one shock absorber device (4), which is alocated to a wheel of the motor vehicle (1) and whose sprung hardness can be adjusted. According to the invention, the control unit (3) is connected to the shock absorber device (4) for the dynamic adjustment of the sprung hardness of the latter (4), which compensates the torque produced by the detected transversal acceleration. The invention also relates to a corresponding method for anti-roll stabilisation.

Description

System and method for roll stabilization of a motor vehicle, in particular buses, vans, off-road vehicles or the like

The invention relates to a system and a method for roll stabilization of a motor vehicle, in particular buses, vans, off-road vehicles or the like. The invention can also be used in so-called sport utility vehicles (SUVs).

Active and passive safety systems in the motor vehicle area play an increasingly important role in the further development of vehicles. Customer expectations require both performance and comfort, aimed at increasing safety for vehicle occupants.

In addition to passive and active safety systems such as airbags, impact protection and belt tensioners, active driving safety with its ever increasing possibilities is becoming increasingly important. The aim of the development is a control system that quickly detects the current driving situation and can immediately actively intervene in any critical situation or provide the driver with a corresponding signal for a manual change in the driving situation. The first steps of active vehicle inspection are already there with the ABS, the ASR or the electronic stability program ESP.

For example, straight-ahead driving of motor vehicles, in particular at high driving speeds or in motor vehicles with an increased vertical extent, is influenced by cross winds or by uneven ground. This results in particular in vehicles in which there is a large distance between the point of application of the resulting wind power and the center of gravity of the vehicle or a large distance between the center of gravity of the vehicle and the wheel contact area, for example in buses, vans, off-road vehicles or the like, when exposed to cross winds or from Uneven ground creates a torque around the longitudinal axis of the vehicle's roll. A lateral turning of the center of gravity leads at least to an unstable driving state and if the center of gravity of the vehicle is turned out beyond the tire-road contact point, the motor vehicle even tilts.

So far, technical vehicle equipment, such as active chassis or active anti-roll bar, are known. However, these approaches have the disadvantage that, on the one hand, they are extremely complex and, on the other hand, they are not primarily designed to compensate for disturbing effects introduced from the outside, such as cross winds or uneven ground.

German Offenlegungsschrift DT 23 31 616 AI describes a device in which a pressure sensor for the air pressure generated by the cross wind is provided on two opposite sides of the vehicle, and an actuator controlled by the differential pressure on both sides of the vehicle, the front axle of the vehicle relative to the driving - longitudinal member moves, which causes a wheel lock in the sense of a counter-steering.

This device according to the prior art has the disadvantage that pressure-actuated working cylinders of large dimensions are necessary to change the relative positions of the components. This requires high manufacturing costs and a large space requirement. Furthermore, the adjustment is not always smooth, so that the driver could be irritated.

The document DE 28 44 413 AI describes a control device for roll stabilization of a vehicle, which causes a stabilizing moment counter to the curve inclination of the vehicle body via hydraulically adjustable spring struts.

A particularly disadvantage of this approach is the fact that the respective front and rear strut are subjected to the same pressure. In this way, for example, when the vehicle is quickly articulated on the front axle, a large, abruptly increasing gravity is caused, which causes the vehicle to oscillate about the vertical axis. Such pendulum movements are associated with oscillating lateral forces and variable slip angles on the vehicle tires, so that the vehicle's driving behavior is unsafe.

Furthermore, the German published patent application DE 38 21 610 AI describes a control device for roll stabilization of a vehicle with force-generating actuators arranged between the wheel carriers or wheel guide elements and the vehicle body, which, depending on the approximately vertical wheelbases of the vehicle body, the lateral acceleration of the Vehicle and the steering wheel angle of rotation counteracting the rolling movements on the vehicle body.

With this approach, however, the fact that additional power-generating actuators have to be provided in the vehicle has been found to be disadvantageous, which not only leads to additional work and additional manufacturing costs, but in particular also to an increase in fuel consumption due to the additional energy requirement of the power-generating actuators leads.

The present invention is therefore based on the object of eliminating the disadvantages described above and of creating a more cost-effective measure by means of which the roll stability of vehicles, in particular with a critically high center of gravity, can be improved, with both vehicle-induced disturbances, such as steering wheel misalignment. Cracks or an ESP intervention, as well as external disturbances, such as cross winds or uneven floors, can be alleviated.

According to the invention, this object is achieved on the device side by the system with the features of claim 1 and on the process side by the method with the features of claim 6.

The idea on which the present invention is based is that at least one transverse acceleration sensor device arranged in the roof area of the motor vehicle, that is to say in the upper region or near the roof of the motor vehicle, is provided for detecting a transverse acceleration acting on the motor vehicle, with a control unit having the at least one a lateral acceleration sensor device for receiving the acquired lateral acceleration data is. Furthermore, at least one shock absorber device, which is assigned to one wheel of the motor vehicle, is equipped with an adjustable hardness setting, the control unit being connected to the at least one shock absorber device for dynamically adjusting a shock absorber hardness of the shock absorber device that compensates for the transverse acceleration detected. A shock absorber equipped with an adjustable hardness setting is preferably assigned to each wheel of the motor vehicle and is in each case connected to the control unit.

The system according to the invention with the features of claim 1 and the method according to the invention with the features of claim 6 have the advantage over the known approaches according to the prior art that they have a slight additional effort and thus cost-effective measures to influence driving comfort and road stability to support stability , Furthermore, a control algorithm can be activated by a new evaluation criterion of the interference, which is equally applicable to both internal and external interference. The degrees of hardness of the individual shock absorbers can be adjusted in accordance with the size and direction of the interference with respect to their rebound and compression, so that a force counteracting the torque caused by the disturbance is generated by the appropriately regulated shock absorber and counteracts a tendency to tip over.

Advantageous developments and improvements of the system specified in claim 1 and of the method specified in claim 6 are found in the subclaims.

According to a preferred development, as already mentioned above, each wheel of the motor vehicle is at least one Adjustable hardness setting associated shock absorber device, which is connected to the control unit.

According to a further preferred development, the at least one transverse acceleration sensor device is arranged centrally in the front roof area of the motor vehicle with respect to the longitudinal axis of the vehicle. Thus, both left-hand and right-hand interference can be detected equally using a single sensor device. Furthermore, the deflection angle of the transverse acceleration sensor device is greatest in the roof area with respect to the roll axis of the vehicle when there are torque-generating influences, as a result of which the system is more sensitive to such interference.

The at least one lateral acceleration sensor device preferably detects the time differential of the lateral acceleration. In this way, more precise statements can be made about torques acting on the vehicle over predetermined periods of time.

According to a further exemplary embodiment, in addition to the (or) transverse acceleration sensor device (s), further transverse acceleration sensors are mounted on the vehicle, for example in the front and / or in the rear wheel axle area. The signals picked up by the additional sensor devices can also be sent to the common control device and evaluated separately or together with the signals of the lateral acceleration sensor provided in the roof area of the vehicle.

The tension spring damper hardnesses of the shock absorber devices are preferably increased on the side of the vehicle from which the transverse acceleration acting on the vehicle power comes from. As an alternative or in addition, the compression spring damper hardnesses of the shock absorber devices on the opposite side of that side of the motor vehicle from which the disruptive transverse acceleration forces originate are preferably increased. Thus, all shock absorber devices or only the shock absorber devices located on the side of the interference force can be dynamically regulated accordingly in order to compensate for the respective lateral acceleration. This can also be carried out in the event of a pendulum movement of the motor vehicle, so that this pendulum movement can be returned to a stable driving state by means of dynamic control. It is conceivable here to store control algorithms of this type in the control unit in such a way that a back-swinging movement of the motor vehicle is recognized and a counter-phase control intervention in the shock absorber devices which counteracts the back-swinging movement is carried out at an early stage.

According to a further exemplary embodiment, in addition to the lateral acceleration, the steering angle of the vehicle can be recorded and also taken into account for the regulation of the suitable shock absorber hardness. The influences to be taken into account for the precise control of the shock absorber hardness can be recorded, for example, by means of a suitable vehicle model that describes the vehicle's dynamic behavior.

Exemplary embodiments of the invention are explained in more detail in the following description with reference to the drawing.

The figure illustrates a schematic rear view of a vehicle, partly in section, with a system for rolling stabilization according to an embodiment of the present invention.

According to the figure, the motor vehicle, for example a coach 1, has a lateral acceleration sensor 2, which is preferably arranged centrally in the front roof area of the coach 1 with respect to the longitudinal axis of the coach. The transverse acceleration sensor 2 can be arranged under the roof panel of the coach. The transverse acceleration sensor 2 is preferably connected via a signal line 20 to a control unit 3, which is also provided in the motor vehicle or the coach 1.

Depending on the motor vehicle type, control algorithms of different complexity can be stored in control unit 3. In many cases it is sufficient to save costs if the data provided by the lateral acceleration sensor 2 is evaluated on the basis of empirically determined vehicle-specific models, the actual evaluation of the data then being able to be carried out using fuzzy logic.

Furthermore, the system according to the invention in accordance with the present exemplary embodiment has shock absorber devices 4, one shock absorber device 4 being assigned to a wheel or wheel set 6 of motor vehicle 1. The shock absorber devices 4 are also each connected to the control unit 3 via signal lines 40 and have an adjustable hardness setting.

In the following, the method according to the invention according to an embodiment of the present invention is explained in more detail with reference to the figure. The transverse acceleration sensor 2 exerts a force on the vehicle 1, measured, for example, by a cross wind gust prevailing in the direction of the arrow. In addition or as an alternative, the time differential of the lateral acceleration, ie the derivative based on time, can be recorded or determined from the lateral acceleration. Thus, for a more reliable statement, the acceleration is detected over a certain period of time in order to avoid unnecessary roll stabilization due to uncritical influences.

The acquired lateral acceleration information or information of the time differentials of the lateral acceleration are sent from the lateral acceleration sensor 2 to the control unit 3 via the signal line 20. The control unit 3 finally evaluates this received information and evaluates the interference by means of an evaluation criterion. In the case of a disturbance variable that critically influences the stability of the vehicle, the control unit sends control signals to the respective shock absorber devices 4 via the control lines 40 in order to amplify the rebound damper hardness, for example on the vehicle side, from which the disturbance acceleration originates. For example, the shock absorber devices 4 are hardened in the rebound in the case of a cross wind prevailing in the direction of the arrow on the right front and right rear side of the vehicle 1. Thus, by increasing the tensile hardness, a torque of the motor vehicle about the roll axis 5 is counteracted counterclockwise according to the figure. A reduction in driving comfort does not occur here.

Alternatively or at the same time, the degree of hardness of the pressure stage of the shock absorber devices 4 on the opposite side of the side from which the wind originates, ie in the figure on the left-hand side of the motor vehicle 1, can be set to be harder, in order also to do so To counteract the torque around the roll axis 5 counterclockwise.

If the vehicle body is able to swing back, the control unit 3 can preferably dynamically control the degrees of hardness of the individual shock absorber devices 4 in such a way that the pendulum movement is counteracted and the vehicle is returned to a stable driving state.

According to a further exemplary embodiment of the present invention, the control mechanism described above can be linked to chassis control mechanisms already provided in the motor vehicle, such as an integrated ESP system. For example, further transverse acceleration sensors, e.g. in the front and rear wheel axle area of the vehicle, the signals of which are combined with the signals of the lateral acceleration sensor 2 in the upper roof area of the vehicle 1 for a more complex dynamic model. The steering angle of the vehicle can also be detected, evaluated and taken into account by the control unit in the case of a corresponding shock absorber control.

It is obvious to a person skilled in the art that the lateral acceleration sensor 2 in the upper roof area of the motor vehicle 1 can also detect and deliver signals for further control interventions, for example for the intervention on the active chassis or for an active anti-roll bar, for a provision regarding a correction angle of an active one Steering and / or for an enlargement of a dynamic servo support for a steering compensation of the interference. Thus, the present invention provides a system and a method for roll stabilization of a motor vehicle, in particular buses, vans, off-road vehicles or the like, in the event of lateral interfering influences, such as cross winds or uneven ground or ground inclinations, in order to adjust the side tilt of the vehicle by correspondingly controlling the shock absorber hardness of the individual To compensate wheels associated shock absorber devices. The differential quotient of the lateral acceleration can advantageously be used in order to massively change the hardness of the rebound or the hardness of the compression on the opposite side.

Furthermore, due to its location in the front roof area of the motor vehicle, the lateral acceleration sensor has a particularly high sensitivity to roll disturbances. This sensitivity is significantly higher than that of a rotation rate sensor around the longitudinal axis and is therefore more meaningful with regard to the totality of the interference, including overlaid interference. In principle, however, it is also conceivable to use a rotation rate sensor of a correspondingly high resolution instead of the lateral acceleration sensor 2.

Although the present invention has been described above on the basis of preferred exemplary embodiments, it is not restricted thereto, but rather can be modified in many ways.

Claims

claims

System for roll stabilization of a motor vehicle, in particular buses, vans, off-road vehicles or the like, with:

at least one transverse acceleration sensor device (2) arranged in the roof area of the motor vehicle (1) for detecting a transverse acceleration acting on the motor vehicle (1);

a control device (3) which is connected to the at least one lateral acceleration sensor device (2) for receiving the acquired lateral acceleration data; and with

at least one shock absorber device (4) which is assigned to a wheel of the motor vehicle (1) and has an adjustable hardness setting;

The control device (3) is connected to the at least one shock absorber device (4) for dynamically adjusting a shock absorber hardness of the shock absorber device (4) which compensates for the torque caused by the detected lateral acceleration. System according to claim 1, characterized in that each wheel or each wheel arrangement (6) of the motor vehicle (1) is assigned at least one shock absorber device (4) which has an adjustable hardness adjustment, which are each connected to the control unit (3).

System according to claim 1 or 2, characterized in that the at least one transverse acceleration sensor device (2) is arranged centrally in the front roof area of the motor vehicle (1) with respect to the longitudinal axis of the motor vehicle (1).

System according to at least one of the preceding claims, characterized in that the at least one lateral acceleration sensor device (2) detects the time differential of the lateral acceleration.

System according to at least one of the preceding claims, characterized in that additional transverse acceleration sensors, for example in the front and / or in the rear wheel axle region of the motor vehicle (1), are additionally provided for supplying additional transverse acceleration data.

Method for roll stabilization of a motor vehicle, in particular buses, vans, off-road vehicles or the like, with the following steps: Detecting a lateral acceleration acting on the motor vehicle (1) by means of at least one transverse acceleration sensor device (2) arranged in the roof area of the motor vehicle (1);

Sending the acquired lateral acceleration data from the at least one lateral acceleration sensor device (2) to a control device (3) connected to the same; and

Dynamic setting of a shock absorber hardness compensating the torque caused by the detected lateral acceleration of at least one shock absorber device (4) assigned to a wheel of the motor vehicle, the hardness setting of which can be regulated in each case.

A method according to claim 6, characterized in that the temporal differential of the lateral acceleration is detected by the at least one lateral acceleration sensor device (2).

A method according to claim 6 or 7, characterized in that the tension spring damper hardnesses of the shock absorber devices (4) are increased on the side of the motor vehicle (1) from which the transverse acceleration force originates.

Method according to at least one of claims 6 to 8, characterized in that the compression spring-damper hardness of the shock absorber devices (4) is increased on the opposite side of that side of the motor vehicle (1) from which the transverse acceleration force originates.

10. The method according to at least one of claims 6 to 9, characterized in that during a pendulum movement of the motor vehicle (1), the shock absorber devices (4) are correspondingly dynamically regulated in order to compensate for the respective torques caused by the pendulum movement.

11. The method according to claim 10, characterized in that a back-swinging movement of the motor vehicle (1) is detected via a control algorithm stored in the control unit (3) and a counter-phase control intervention in the shock absorber devices (4) which counteracts the back-swinging movement is carried out.

12. The method according to claim 10 or 11, characterized in that the detection of the pendulum movement of the motor vehicle (1) is based on empirically determined vehicle-specific models, fuzzy logic being used to regulate the suitable shock absorber hardness.

13. The method according to at least one of claims 6 to 12, characterized in that in addition to the transverse acceleration, the steering angle of the motor vehicle (1) is detected and taken into account for the regulation of the suitable shock absorber hardness.