ADAPTIVE CRUISE CONTROL SYSTEM

• US 20110040467A1
• Filed: 12/19/2008
• Published: 02/17/2011
• Est. Priority Date: 03/18/2008
• Status: Active Grant

• Current Assignee: ZF CV Systems Europe BV
• Original Assignee: Wabco GmbH (Wabco Holdings Incorporated)
• Inventors: Breuer, Karsten
• Granted Patent: US 8,396,642 B2
• Time in Patent Office: Days
• US Class Current: 701/96
• CPC Class Codes: B60T 7/22 initiated by contact of vehicle, e.g. bumper, with an external object, e.g. another vehicle , or by means of contactless obstacle detectors mounted on the vehicle
• CPC Class Codes: B60W 10/04 including control of propulsion units
• CPC Class Codes: B60W 10/18 including control of braking systems
• CPC Class Codes: B60W 2050/0083 Setting, resetting, calibration
• CPC Class Codes: B60W 2510/184 Brake temperature, e.g. of fluid, pads or discs
• CPC Class Codes: B60W 2552/40 Coefficient of friction
• CPC Class Codes: B60W 2720/106 Longitudinal acceleration
• CPC Class Codes: B60W 30/095 Predicting travel path or likelihood of collision
• CPC Class Codes: B60W 30/16 Control of distance between vehicles, e.g. keeping a distance to preceding vehicle
• CPC Class Codes: B60W 50/14 Means for informing the driver, warning the driver or prompting a driver intervention

Abstract

The invention relates to an adaptive cruise control system for a motor vehicle, having a service brake comprising an electric controller (24), which is equipped to detect the driving data of the motor vehicle and distance data to a preceding vehicle, to compile a movement prediction based on the driving data and the distance data, to influence the state of movement of the motor vehicle by influencing the driving and braking means, and to output a warning signal to a drive of the motor vehicle (10), if the movement prediction indicates that, assuming a predetermined threshold delay (a_grenz), an impact probability of an impact with another motor vehicle, with the adaptive cruise control system being activated, exceeds a predetermined impact probability threshold value without any intervention on the part of the drive of the motor vehicle. The invention provides that the electric controller (24) is equipped to detect braking parameters, based on which a maximum brake delay (a_max) that can be achieved with the service brakes can be calculated, and to reduce the threshold delay (a_grenz), if the maximum brake delay (a_max) is below a predetermined delay threshold value.

Claims

1. A headway regulated cruise controller for a motor vehicle having a service brake, which comprises an electric controller (24), which is set up to

(a) detect driving data of the motor vehicle and distance data with respect to a preceding vehicle,

(b) produce a motion prediction from the driving data and the distance data,

(c) influence the state of motion of the motor vehicle by influencing driving or braking means, and

(d) output a warning signal to a driver of the motor vehicle (10) if the motion prediction shows that, assuming a predetermined limiting retardation (a_grenz), a collision probability of a collision with another motor vehicle with the headway regulated cruise controller activated and without an intervention by a driver of the motor vehicle exceeds a predetermined collision probability threshold value,

characterized in that the electric controller (24) is set up to

(e) detect braking parameters by means of which a maximum braking retardation (a_max) that can be achieved with the service brakes can be calculated and

(f) reduce the limiting retardation (a_grenz) if the maximum braking retardation (a_max) falls below a predetermined retardation threshold value.

2. The headway regulated cruise controller as claimed in claim 1, characterized in that the retardation threshold value is the limiting retardation.

3. The headway regulated cruise controller as claimed in one of the preceding claims, characterized in that the electric controller (24) is set up to reduce the limiting retardation to a product of the maximum braking retardation with a safety factor.

4. The headway regulated cruise controller as claimed in one of the preceding claims, characterized in that the braking parameter is a temperature of the service brakes and/or a maximum torque that can be applied to a wheel, which is detected by way of a closed-loop anti-slip controller.

5. The headway regulated cruise controller as claimed in claim 4, characterized in that the electric controller is set up to extract the braking parameter from an EBC5 message which the brake system sends via a data bus of the motor vehicle.

6. The headway regulated cruise controller as claimed in one of the preceding claims, characterized in that the electric controller is set up to

detect whether an anti-lock system of the motor vehicle has been active for the purpose of controlling the service brake within a predetermined time interval,

detect the braking retardation achieved by the anti-lock system and determine the maximum braking retardation from the braking retardation achieved.

7. The headway regulated cruise controller as claimed in claim 6, characterized in that the electric controller is set up to

detect whether the anti-lock system is currently controlling the service brake,

detect the maximum instantaneously achievable braking retardation by the anti-lock system, and

determine the limiting retardation from the instantaneously achieved braking retardation.

8. The headway regulated cruise controller as claimed in claim 7, characterized in that the electric controller is set up to

extract an “

ABS control active”

signal from an EBC1 message which the anti-lock system sends via a data bus of the motor vehicle, and

determine the braking parameter from a retardation determined by means of linear vehicle and/or wheel speeds or from a retardation detected directly by means of a sensor.

9. A motor vehicle having a headway regulated cruise controller as claimed in one of the preceding claims.

10. A method for operating a headway regulated cruise controller having the following steps:

(a) detecting driving data of the motor vehicle and distance data with respect to a preceding vehicle,

(b) producing a motion prediction from the driving data and the distance data, influencing the state of motion of the motor vehicle by influencing driving or braking means, and

(c) outputting a warning signal to a driver of the motor vehicle if the motion prediction shows that, assuming a predetermined limiting retardation, a collision probability of a collision with another motor vehicle exceeds a predetermined collision probability threshold value,

(d) calculating a maximum achievable braking retardation from braking parameters of the service brakes, and

(e) reducing the limiting retardation if the maximum braking retardation falls below a predetermined retardation threshold value.

11. The method as claimed in claim 10, characterized in that it is continuously repeated.