DE102017209570A1 - Method for braking a vehicle - Google Patents

Abstract

A method is proposed for braking a vehicle (1) in an automated parking or maneuvering maneuver, wherein the vehicle comprises at least one vehicle braking system and wherein, in the event of a malfunction of the vehicle braking system during an automated parking or maneuvering maneuver, the steering of the vehicle (1) is triggered in such a way is that at least one tire of the vehicle is brought into contact with a suitable obstacle (3), in particular without overriding the obstacle.

Description

State of the art

Modern vehicles are increasingly equipped with assistance systems to relieve the driver. In addition to assistance systems in a high speed range such. Automated Cruise Control (ACC) also assistance systems to facilitate parking and maneuvering, which are used at low speeds. In a simple embodiment, these assistance systems for parking and maneuvering take over the lateral guidance of the vehicle, while the driver is responsible for the longitudinal guidance. In a broader embodiment, the longitudinal guidance of the parking or maneuvering process is taken over by the vehicle, but the driver usually has to monitor the function and thus bring the vehicle to a halt by operating the brake pedal or the parking brake, in particular in the event of a malfunction or malfunction of the assistance system can.

On the way to autonomous driving such parking and maneuver assistance systems play an increasingly important role, which the driver only has to monitor from outside the vehicle or not at all. In the event of a malfunction, this results in higher demands on the backup braking system. For this purpose, for example, the automatic parking brake (APB) can be used. A disadvantage of using the automatic parking brake is that the stopping distance increases greatly in the event of a fault, since the automatic parking brake usually acts on only one axis and it may take more than a second for the automatic parking brake to be completely closed.

In the DE 10 2015 206 582 A1 Methods for terminating a regular automated parking maneuver are described. Here, in addition to the brake control system and the automatic parking brake and the pawl of the transmission is used.

In the DE 10 2015 214 117 A1 A method is described for stopping a vehicle during an automated parking maneuver in case of failure using the automatic parking brake.

Disclosure of the invention

The object of the invention is to reduce the stopping distance in the event of a malfunction during an automated parking or maneuvering maneuver compared to the prior art and thus to increase the safety of automated driving maneuvers.

A method is proposed for braking a vehicle during an automated parking or maneuvering maneuver, wherein the vehicle comprises at least one vehicle braking system and wherein, when a malfunction of the vehicle braking system during an automated parking or maneuvering maneuver, the steering of the vehicle is controlled such that at least one Tires of the vehicle is brought into contact with a suitable obstacle, in particular without overriding the obstacle.

It is therefore provided in the event of an error obstacle, such. a curb, targeted to touch at least one tire of the vehicle, so as to brake the vehicle faster to a standstill. In particular, the invention is based on the idea, in the event of an error, of not only a backup braking system, such as e.g. to use the automatic parking brake to bring the vehicle to a safe state, but to include the steering. In principle, the steering should be used in the event of a fault to bring the tires in contact with a suitable obstacle, preferably without overriding the obstacle. In particular, the obstacle may be a curb. The deliberately brought about contact of at least one tire with the obstacle, the vehicle is additionally delayed and the stopping distance is shortened.

This results in particular the following advantages:

On the one hand, the shortening of the stopping distance increases the safety of the automated parking function. Furthermore, in the solutions known from the state of the art, functional limitations often arise due to the comparatively long stopping distance, for example with regard to the permissible speeds or gradients. By shortening the stopping distance according to the present invention, the parking function can be used outside of these limitations.

Obstacles in the surroundings of the vehicle are preferably detected by an environment sensor system of the vehicle and geometric parameters, in particular the height, of the detected obstacles are determined. A suitable obstacle is selected based on the geometric parameters. Particularly preferably, a curb is selected as a suitable obstacle. Preferably, the steering angle at the time of contact is selected so that the obstacle is not run over. For this purpose, it is particularly advantageous if, in addition to the orientation of the obstacle, its geometry (in particular height) is also detected by the environmental sensor system. Together with the estimated speed at the time of impact can thus be estimated which steering angle must be used so as not to run over the obstacle. This embodiment has the particular advantage that z. B. in the event that the obstacle is a curb, the vehicle remains on the safe side of the curb (road). For example, it is conceivable that there is no paved road or abyss just behind the curb. Furthermore, no potentially on the curb persons are endangered. As a result, the security is further increased.

For example, an existing sensor system of the parking assistance system can be used as environment sensor. For the detection and measurement of parking spaces as well as objects in the vehicle environment, parking assistance systems usually have distance sensors, which may be designed, for example, as ultrasonic sensors or radar sensors or lidar sensors or video sensors. It is also possible to use a combination of different sensor types. This environment sensor system can advantageously also be used for the detection of suitable obstacles in the vehicle environment in the sense of the present invention. In this way, advantageously no separate environment sensor system must be provided.

Furthermore, it is advantageous if the steering angle during the entire stopping maneuver is always chosen so that there is a maximum delay by the contact with the obstacle, without the risk of overriding the obstacle. This further shortens the stopping distance and increases safety.

In a further preferred embodiment, the steering angle is selected so that a rim of the touching wheel is not damaged by the obstacle. For example, very flat steering angles can be ruled out against a curb.

In particular, the vehicle has at least one primary vehicle brake system and at least one backup brake system, in particular an automatic parking brake. In the event of a malfunction of the primary vehicle brake system during an automated parking or maneuvering maneuver, the backup braking system now preferably also becomes active.

Particularly preferably, the orientation of the vehicle relative to the obstacle is determined. Depending on the orientation and direction of travel of the vehicle, an associated amount of time may be estimated for each tire until the respective tire can be brought into contact with the obstacle. The steering may be controlled such that either a front axle tire or a rear axle tire is brought into contact with the obstacle depending on the respective estimated time period. The period of time until the contact of a tire with the obstacle can be preferably calculated, wherein additionally an adjustment speed of the steering of the vehicle is taken into account. The decision as to whether a tire of a front wheel or a tire of a rear wheel should be used can be made on the basis of the estimated time to contact, with the shorter time being preferred. This embodiment has the particular advantage that, depending on the orientation of the vehicle relative to the obstacle, a further reduction of the stopping distance can be achieved. For these and other embodiments of the invention, it is advantageous if the environment sensor system detects the exact orientation of the vehicle relative to the obstacle (eg curb). The orientation of the vehicle relative to the obstacle is preferably determined by means of an environment sensor system of the vehicle.

In the event that the vehicle has a rear axle steering and that the orientation of the vehicle is determined relative to the obstacle can preferably depending on the orientation of the vehicle, the Hinterachslenkung be driven in opposite directions to the steering of the front axle. So can be made within a relatively short time a contact between a tire and an obstacle and the vehicle can be brought to a standstill faster.

Preferably, to calculate the time until the contact between the tire and the obstacle, the control speed of the steering is additionally taken into account. The positioning speed causes a characteristic of the respective steering time during the adjustment between the actual and target steering angle results. Depending on the orientation of the vehicle and the obstacle, it may happen, for example, that additional time is lost as a result of the steering operation. If the positioning speed is taken into account, there is the advantage that the time to contact between tire and obstacle can be determined even more accurately and in the case of alternatives, for. As in the decision whether a contact with a front wheel or a rear wheel to be made, see above, the better alternative can be determined more accurately.

According to a further aspect of the invention, a vehicle is provided, which is set up to carry out a method as described above. The vehicle has a parking or maneuvering assistance system, comprising an environment sensor system, in particular a video, radar, ultrasound and / or Lidarsensorik, which is adapted to the environment of the vehicle with respect to a suitable obstacle, in particular a curb. The vehicle also has an actuator, in particular a brake control system, an automatic parking brake, an electronic brake booster, an integrated power brake and / or an electronic power steering, and a control unit which is set up to control the actuators. In addition, the vehicle has a monitoring unit which is set up to monitor the parking or maneuvering assistance system for a malfunction of the actuators, and a steering system which is set up to control the steering of the vehicle such that at least one tire of the vehicle is in contact with the appropriate one Obstacle is coming.

The vehicle preferably has a primary brake system and at least one backup brake system, wherein in case of a malfunction of the primary brake system, the backup brake system becomes additionally active.

list of figures

• 1 represents an embodiment of a method according to the invention as a flowchart.
• The 2 a) -d ) show schematically in plan view situations during the performance of an automatic parking or maneuvering operation.

Embodiments of the invention

In the following description of the embodiments of the invention, the same elements are denoted by the same reference numerals, wherein a repeated description of these elements is optionally omitted. The figures illustrate the subject matter of the invention only schematically.

1 shows a flowchart of a preferred embodiment of the invention. The method according to this embodiment comprises at least the following steps:

step 100 : Provision of a vehicle which is designed to perform an automated parking or maneuvering maneuver. For this purpose, the vehicle can in particular be equipped with a suitable environment sensor system, which, for. B. video sensors, radar sensors, ultrasonic sensors and / or Lidarsensoren and is designed to monitor the vehicle environment, a suitable actuator (eg., Brake control system, APB, electronic brake booster (iBooster), Integrated Power Brake (IPB), Electronic Power Steering ( EPS)) and corresponding software components.

step 120 : Monitoring the parking or maneuvering function for an error, in particular a fault of the brake system. The monitoring is advantageously implemented as a software function, which controls, for example, the state of a brake control system, for example by a cyclical test for availability. Alternatively, the monitoring can also take place via redundant hardware measures, for. As an ASIC, which can initiate measures in the event of a fault independent of other microcontrollers. Possible errors of the brake control system include, for example, hydraulic errors or failure of the brake control system microcontroller.

At the same time in step 140 a monitoring of the environment of the vehicle with regard to a suitable obstacle with the help of the existing environment sensors. The obstacle may preferably be a curb.

In case of a fault, eg in the primary brake system, take place in step 160 the activation of the backup braking system (eg the automatic parking brake) and if a suitable obstacle in the vicinity of the vehicle has previously been detected, driving the steering such that at least one tire of the vehicle comes into contact with the obstacle as quickly as possible.

2 a) -d ) shows a timing sequence for illustrating embodiment of the invention. In 2 a) is shown at a start time a vehicle 1 on a lane with a left lane boundary 2 and a right lane boundary, where the right lane boundary exemplifies a curb 3 having. The position of the wheels 4a and 4b the front axle 4 and the wheels 5a and 5b the rear axle 5 is aligned parallel to the curb at this time. At a later time ( 2 B) For example, an error occurs in the primary brake system of the vehicle 1 on what a backup braking system is active, eg. As an automatic parking brake, which on the wheels of the rear axle 5 acts. Alternatively or additionally, a backup brake system can also be an electronic brake booster ("iBooster") or a redundant brake unit, which can be used on all 4 Wheels works, be provided. At the same time, the position of the front wheels according to the invention 4 in the direction of the curb 3 changed. At a later time ( 2 c) ) it will then in this example to a contact between the right front wheel 4b and the curb 3 come, causing the vehicle to be delayed and brought to a standstill. The delay effect can in particular already come into play when the backup braking system has to overcome a certain amount of dead time, which may be conditionally present due to the design (eg the automatic parking brake, which due to the Bridging the air gap between the brake pads and the brake disc still generates no braking torque). However, it also results in a shortening of the stopping distance when a braking torque of the backup brake system (eg automatic parking brake) already exists, while a contact between the tire and curb occurs. The inventive method thus significantly supports the deceleration of the vehicle during the rolling phase or the period in which possibly the vehicle is delayed by a blocked rear axle. In 2d) is shown by way of example the situation according to the time 2c) corresponds without the inventive method has been used. It results in a distance d longer stopping distance, since only the backup braking system was used for braking.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102015206582 A1 [0003]
• DE 102015214117 A1 [0004]

Claims (10)

Method for braking a vehicle (1) in an automated parking or maneuvering maneuver, wherein the vehicle comprises at least one vehicle braking system, characterized in that in a detected malfunction of the vehicle braking system during an automated parking or maneuvering maneuver, the steering of the vehicle is controlled such that at least one tire (4a, 4b, 5a, 5b) of the vehicle (1) is brought into contact with a suitable obstacle (3), in particular without passing over the obstacle. Method according to Claim 1 , characterized in that obstacles (3) in the surroundings of the vehicle (1) are detected by an environment sensor system of the vehicle (1) and geometric parameters, in particular the height, of the detected obstacles (3) are determined and a suitable obstacle (3) is selected based on the geometric parameters. Method according to one of Claims 1 or 2 , characterized in that a curb (3) is selected as a suitable obstacle. Method according to one of Claims 1 to 3 characterized in that the vehicle (1) comprises at least a primary vehicle braking system and at least one backup braking system, in particular an automatic parking brake, and that during a malfunction of the primary vehicle braking system during an automated parking or maneuvering maneuver, the backup braking system becomes active. Method according to one of Claims 1 to 4 characterized in that the orientation of the vehicle (1) relative to the obstacle (3) is determined and depending on the orientation and direction of travel of the vehicle (1) for each tire (4a, 4b, 5a, 5b) a respective period of time is estimated until the respective tire (4a, 4b, 5a, 5b) can be brought into contact with the obstacle (3), and the steering is controlled such that depending on the respective estimated time period either a tire (4a, 4b) the front axle (4) or a tire (5a, 5b) of the rear axle (5) is brought into contact with the obstacle (3). Method according to one of Claims 1 to 5 , characterized in that the vehicle (1) has a Hinterachslenkung and that the orientation of the vehicle (1) relative to the obstacle determines (3) and depending on the orientation, the rear axle is driven in opposite directions to the steering of the front axle. Method according to one of Claims 5 or 6 , characterized in that the orientation of the vehicle (1) relative to the obstacle (3) by means of an environmental sensor of the vehicle (1) is determined. Method according to one of Claim 5 to 7 , characterized in that the time period until the contact of a tire (4a, 4b, 5a, 5b) with the obstacle (3) is calculated, wherein additionally an actuating speed of the steering of the vehicle (1) is taken into account. Vehicle (1) arranged to carry out a method according to one of Claims 1 to 8th comprising - a parking or maneuvering assistance system comprising an environment sensor system, in particular a video, radar, ultrasound and / or Lidarsensorik which is adapted to monitor the environment of the vehicle (1) with respect to a suitable obstacle (3), in particular a curb an actuator system comprising in particular a brake control system, an automatic parking brake, an electronic brake booster, an integrated power brake and / or an electronic power steering, a control unit that is set up to control the actuators, a monitoring unit that is set up monitor the parking or maneuvering assistance system for a malfunction of the actuators, a steering system which is set up to control the steering of the vehicle so that at least one tire (4a, 4b, 5a, 5b) of the vehicle is in contact with the suitable obstacle (FIG. 3) comes. Vehicle after Claim 9 characterized in that the vehicle (1) comprises a primary brake system and at least one backup brake system, wherein a case of a malfunction of the primary brake system, the backup brake system is additionally active.

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