DE102019206537A1 - Method for operating a motor vehicle - Google Patents

Abstract

The invention relates to a method for operating a motor vehicle (2) with electrically assisted steering (4), with the following steps: (S100) determining a data set (D1) representative of a driving trajectory (I) during an autonomous operating phase of the motor vehicle (2) , (S200) evaluating the data set (D1) with the addition of operating parameters (BP) of the steering (4) of the motor vehicle (2), and (S300) providing a further data set (D2) representative of a modified driving trajectory (II).

Description

The invention relates to a method for operating a motor vehicle.

Nowadays, many motor vehicles have power steering to reduce the force that is required to operate the steering wheel of a motor vehicle when steering while stationary, when maneuvering or at low driving speeds. The power steering assists the driver in steering by increasing the steering force exerted by the driver using a hydraulic system or an electric motor.

With an electric drive, a program-controlled electric servomotor supports and superimposes the steering movements of the driver on the mechanics of the steering (steering column or steering gear) (also called Electric Power Assisted Steering - EPAS).

The main advantage of the electric drive is that the steering can be designed to be adaptive and can also be overlaid by the driver assistance systems of the motor vehicle. The steering system can be used as an actuator for further driver assistance tasks, such as for automatic steering interventions by a park steering assistant (also called Active Park Assist - APA) also or by a remote-controlled parking assistant (also called Remote Park Assist - RePA).

From the US 9211912 a method and a control device for dynamically adapting operating parameters of a motor vehicle with a park-steering assistant are known. Also is from the US 9211912 known to take a tire pressure into account.

From the DE 10 2012 216986 A1 a method for operating a parking steering assistant is known in which values for coefficients of friction are determined.

Another park steering assistant is known from US 2017/0129538 A1.

However, power restrictions of the steering of the motor vehicle are not taken into account in the trajectory planning by such a parking steering assistant or remote-controlled parking assistant. This can lead to deviations from the planned driving trajectory during an autonomous operating phase.

There is therefore a need to show ways how this can be remedied.

• Bestimmen eines Datensatzes repräsentativ für eine Fahrtrajektorie während einer autonomen Betriebsphase des Kraftfahrzeugs,
• Auswerten des Datensatzes unter Hinzuziehung von Betriebsparametern der Lenkung des Kraftfahrzeugs, und
• Bereitstellen eines weiteren Datensatzes repräsentativ für eine modifizierte Fahrtrajektorie.

The object of the invention is achieved by a method for operating a motor vehicle with electrically assisted steering, with the steps:

• Determination of a data set representative of a driving trajectory during an autonomous operating phase of the motor vehicle,
• Evaluating the data set with reference to operating parameters of the steering of the motor vehicle, and
• Provision of a further data set representative of a modified driving trajectory.

The autonomous operating phase can be a phase during which the motor vehicle is supported by a driver assistance system, e.g. is controlled by a parking assistant or a remote-controlled parking assistant. In other words, the driver does not actuate the steering wheel of the motor vehicle; a torque that adjusts the steerable wheels of the motor vehicle is provided solely by the electric drive of the steering of the motor vehicle.

By taking into account operating parameters of the steering of the motor vehicle, in particular temporary performance weaknesses of components of the steering, but also permanent and aging-related, gradually increasing performance deficits of components of the steering can be taken into account and also compensated.

A deviation from the planned travel trajectory by the motor vehicle can thus be counteracted during an autonomous operating phase.

According to one embodiment, the operating parameters have values representative of a current steering angle and / or an outside air temperature and / or a module / engine temperature and / or a vehicle speed and / or a battery voltage and / or road friction. In this way, it can be determined in a particularly simple manner whether there are temporary weaknesses in performance of components of the steering system and / or performance deficits of steering components that are gradually increasing due to aging.

According to a further embodiment, a lookup table is used to evaluate the data record with the aid of operating parameters. Lookup tables (also LUT or conversion tables) are used to statically define information and make it available while avoiding complex calculations and / or high memory requirements. Values for operating parameters are stored in the lookup table that corresponding control parameters for components of the steering of the motor vehicle are assigned.

According to a further embodiment, the further data set has data for driving speed values representative of a modified driving trajectory. E.g. by specifying an increased driving speed during a maneuver, e.g. For parking in a parking space, the torque expenditure for a steering movement for adjusting the steerable wheels of the motor vehicle can be reduced.

The invention also includes a computer program product, a control device and a motor vehicle with such a control device.

• 1 in schematischer Darstellung ein Szenario, bei dem ein Kraftfahrzeug autonom in eine Parklücke einparkt.
• 2 in schematischer Darstellung einen Verfahrensablauf.

The invention will now be explained with reference to a drawing. Show it:

• 1 a schematic representation of a scenario in which a motor vehicle parks autonomously in a parking space.
• 2 a schematic representation of a process sequence.

It will be on first 1 Referenced.

A motor vehicle is shown 2 that in a parking space 10 is parked in the front of another motor vehicle 12 is limited.

The car 2 is in the present embodiment a car. Furthermore, the motor vehicle 2 in the present embodiment an electrically assisted steering 4th on.

The electrically assisted steering 4th supports a driver in steering by increasing the steering force applied by the driver by an electric motor. A program-controlled electric servomotor supports and superimposes this on the mechanics of the steering 4th (Steering column or steering gear) the steering movements of the driver.

Furthermore, the motor vehicle 2 in the present exemplary embodiment a control device 6th and environment sensors 8th on. While the control unit 6th provides the function of a park steering assistant and / or a remote-controlled parking assistant, provide the environment sensors 8th (e.g. LIDAR, RADAR or ultrasonic sensors or camera systems) the environment data UD (please refer 2 ) for the control unit 6th ready. For the tasks and functions described below, the control unit 6th Have hardware and / or software components.

The park steering assistant supports a driver when parking by completely taking over the steering maneuvers required for parking. After activating the park steering assistant by pressing a button or falling below a certain speed, the environment sensors measure 8th of the motor vehicle 2 one or more parking spaces while driving past 10 . If this is large enough, this is indicated to the driver. The park assist then uses steering and engine interventions to automatically park in the parking space 10 if the park assist is designed to be self-driving. If the parking assistant is only self-steering, the driver has the motor vehicle 2 set in motion by selecting a gear and actuating the accelerator pedal, while the parking assistant controls the motor vehicle 2 through steering intervention in the parking space 10 controls.

The remote-controlled parking assistant also assists a driver when parking, but allows the driver to get out of the vehicle before parking 2 gets out and then controls the motor vehicle only with the help of a handheld, such as a smartphone.

In both cases, the driver operates the steering wheel of the motor vehicle 2 Not. One of the steerable wheels of the motor vehicle 2 adjusting torque is provided solely by the electric drive of the steering 4th of the motor vehicle 2 provided.

The one for parking in the parking space 10 necessary steering maneuvers are made by the control unit 6th , for example with the help of clothoid tracks with a constant angular course. The necessary steering maneuvers are recorded in a data record D1 (please refer 2 ) summarized. In other words, the record D1 is representative of a driving trajectory I. during an autonomous operating phase of the motor vehicle 2 while alone the control unit 6th the car 2 controls.

However, there are still power limitations of the steering 4th of the motor vehicle 2 in the trajectory planning by the control unit 6th disregarded. This can lead to deviations from the planned driving trajectory during an autonomous operating phase I. to lead.

To counteract this is the control unit 6th trained to use the already determined data set D1 with the inclusion of operating parameters BP (please refer 2 ) the steering 4th to evaluate.

The operating parameters BP can have values representative of a current steering angle and / or an outside air temperature and / or a module / engine temperature and / or a vehicle speed and / or a battery voltage and / or road friction.

To evaluate the data set D1 with reference to the operating parameters BP uses the control unit 6th a lookup table. The lookup table contains the corresponding values of the operating parameters BP Values for corresponding control parameters for steering components 4th , such as the electric servomotor, stored.

The control unit 6th then creates another record D2 (please refer 2 ) representative of a modified driving trajectory II ready in which the deviations are minimized. In addition, the further data record D2 also have data for vehicle speed values.

For example, by specifying an increased driving speed during a maneuver to park in the parking space 10 the torque required for a steering movement to adjust the steerable wheels of the motor vehicle 2 be reduced.

It is now additionally on 2 Referenced.

The procedure begins with a first step S100 , according to the control unit 6th the parking space 10 by evaluating the from the environment sensors 8th provided environment data UD was recorded

In the first step S100 now determines the control unit 6th by evaluating the surrounding data UD the record D1 representative of the driving trajectory I. during an autonomous operating phase of the motor vehicle 2 for parking in the parking space 10 .

In a further step S200 the control unit reads the operating parameters BP , in the present exemplary embodiment values representative of a current steering angle and / or an outside air temperature and / or a module / engine temperature and / or a vehicle speed and / or a battery voltage and / or road friction.

The control unit also evaluates 6th the record D1 and the operating parameters BP out. The control unit intervenes for this purpose 6th back to a lookup table. The lookup table contains the operating parameters for the corresponding values BP Values for corresponding control parameters for steering components 4th of the motor vehicle 2 deposited. For example, a battery voltage that is too low can be assigned a reduced value for a maximum steering speed. In other words, a reduced battery voltage leads to slower steering movements. The corresponding control parameter ensures that corresponding steering movements are initiated earlier by steering interventions.

In a further step S300 represents the control unit 6th then the further data set D2 representative of the modified driving trajectory II ready.

The further data record D2 in the present embodiment, additional data for vehicle speed values. For example, by specifying an increased driving speed during the maneuver, you can park in the parking space 10 the torque required for a steering movement to adjust the steerable wheels of the motor vehicle 2 reduced. In addition or as an alternative, it is thus possible to compensate for the fact that an operating parameter, such as a reduced battery voltage, leads to slower steering movements.

Eventually the motor vehicle will 2 from the control unit 6th according to the further data set D2 and thus according to the further travel trajectory II through steering and, if necessary, engine intervention in the parking space 10 parked.

So there can be a deviation from the planned driving trajectory I. by the motor vehicle 2 can be counteracted during an autonomous operating phase.

List of reference symbols

2

Motor vehicle

4th

steering

6th

Control unit

8th

Environment sensors

10

parking lot

12

Motor vehicle

BP

Operating parameters

D1

record

D2

record

UD

Environment data

I.

Driving trajectory

II

Driving trajectory

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was 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.

Patent literature cited

• US 9211912 [0005]
• DE 102012216986 A1 [0006]

Claims (10)

Method for operating a motor vehicle (2) with an electrically assisted steering (4), comprising the steps: (S100) determining a data record (D1) representative of a driving trajectory (I) during an autonomous operating phase of the motor vehicle (2), (S200) evaluating the data set (D1) with the aid of operating parameters (BP) of the steering system (4) of the motor vehicle (2), and (S300) Provision of a further data record (D2) representative of a modified driving trajectory (II). Procedure according to Claim 1 , wherein the operating parameters (BP) have values representative of a current steering angle and / or an outside air temperature and / or a module / engine temperature and / or a vehicle speed and / or a battery voltage and / or a road friction. Procedure according to Claim 1 or 2 , a lookup table being used to evaluate the data record (D1) with the addition of operating parameters (BP). Procedure according to Claim 1 , 2 or 3 , the further data set (D2) having data for driving speed values representative of a modified driving trajectory (II). Computer program product designed to carry out a method according to one of the Claims 1 to 4th . Control unit (6) for operating a motor vehicle (2) with electrically assisted steering (4), the control unit (6) being designed to generate a data set (D1) representative of a driving trajectory (I) during an autonomous operating phase of the motor vehicle (2 ) to determine, evaluate the data set (D1) with the addition of operating parameters (BP) of the steering (4) of the motor vehicle (2) and provide a further data set (D2) representative of a modified driving trajectory (II). Control unit (6) Claim 6 , wherein the operating parameters (BP) have values representative of a current steering angle and / or an outside air temperature and / or a module / engine temperature and / or a vehicle speed and / or a battery voltage and / or a road friction. Control unit (6) Claim 6 or 7th , the control device (6) being designed to use a lookup table for evaluating the data record (D1) with the aid of operating parameters (BP). Control unit (6) Claim 6 , 7th or 8th , the control device (6) being designed to provide a further data set (D2) representative of a modified driving trajectory (II) with data for driving speed values. Motor vehicle (2) with a control unit (6) according to one of the Claims 6 to 9 .

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