DE102015224389B4 - Assistance system with load compensation - Google Patents

Abstract

Method for compensating for the loading of a motor vehicle in an assistance system (1, 11) of the motor vehicle, the assistance system (1, 11) intervening in the steering of the motor vehicle, a loading condition of the motor vehicle being determined, the assistance system having a steering angle and a steering angle speed below Determined taking into account the load condition, the assistance system (11) that intervenes in the steering being formed by a PLA, and the determined steering angle and the steering angle speed are set on the steering.

Description

The invention relates to a method for load compensation in assistance systems, the intervention of which takes place via the steering, and a corresponding assistance system of a motor vehicle for carrying out the method.

With today's assistance systems in the passenger car sector, the vehicle load usually plays no role, since the payload in the passenger car sector has a subordinate influence on the driving behavior, at least if the payload is within the usual range. However, in the commercial vehicle sector, the impact of payload on commercial vehicle driveability is significantly greater due to the significant difference between the unloaded and loaded states.

The pamphlet DE 10 2005 048 718 A1 describes a system and method for dynamically determining vehicle loading and vertical load spacing for use in a vehicle dynamics control system, the control system including a roll rate sensor that generates a roll rate signal, a lateral acceleration sensor that generates a lateral acceleration signal, a longitudinal acceleration sensor that generates a longitudinal acceleration signal, and a yaw rate sensor that generates a yaw rate signal. A security system and the sensors are coupled to a controller. The control device determines an added mass and the magnitude of the added mass or a roll gradient, a roll acceleration coefficient and/or a roll rate parameter that takes into account the added mass and the magnitude using the roll rate, the lateral acceleration, the longitudinal acceleration and the yaw rate, and controls the safety system reaction to it.

The pamphlet WO 2008/037509 A1 relates to a method for operating a vehicle, the vehicle having wheel suspensions and characteristic curves associated with them. The characteristic curves each establish a relationship between the weight of the vehicle acting proportionally on the respective wheel suspension and the respective height of the vehicle at the wheel suspension point. The vehicle also has at least two ride height sensors for detecting the ride heights on the wheel suspensions, with each ride height sensor being assigned a reference ride height that is representative of a predetermined loading condition of the vehicle. The ride heights are recorded and the forces acting on the vehicle and the acceleration of the vehicle are determined on the basis of the forces acting on the vehicle. An estimated value for the mass of the vehicle is determined from the forces acting on the vehicle and the acceleration of the vehicle.

The pamphlet DE 10 2010 031 464 A1 describes a method for detecting the loading condition of a motor vehicle, which uses wheel speed information and/or information from directly measuring tire pressure monitoring systems in order to determine the tire pressures. The wheel loads are increased by an additional load, which usually also shifts the center of gravity of the vehicle. When rolling, more heavily loaded wheels also show a greater increase in temperature. The pressure difference between the tires on the front and rear axles, which arises as a result of the increase in temperature while driving, is evaluated in order to identify the load status of the vehicle.

The pamphlet DE 10150605 A1 relates to a method for stabilizing a multi-lane motor vehicle, wherein a yaw moment caused by braking operations with different braking forces at the individual edges, which is determined in particular from the determined difference in braking force, is at least partially compensated for by an intervention in a controllable steering system of the vehicle, and wherein furthermore, the transverse acceleration occurring when cornering is taken into account in a manner that reduces the compensation steering angle. The load condition of the motor vehicle and/or the determined tire pressure in the vehicle wheels and/or the utilization of the frictional connection on the steered wheels should now also be included in the determination of the compensation steering angle. The compensation steering angle can be determined using a map or a vehicle dynamics model.

The pamphlet EP 1 987 710 A1 relates to automatic steering for a working vehicle comprising a position sensor for detecting a position of the vehicle, a memory for storing information about a nominal path of the vehicle and a control unit which is coupled to the position sensor, the memory and a steering actuator for steering the vehicle. The controller sends control signals to the steering actuator that depend on a feedback gain and a lateral offset between the actual position and the nominal path. The feedback gain depends on a detected payload of the vehicle.

The pamphlet DE 10 2009 057 625 A1 relates to a motor vehicle steering system comprising a control unit for providing a control signal for a servo unit that assists the driver in steering, in which a calculation rule for determining the control signal on the basis of a steering command from the driver is stored, a device arranged on the vehicle for determining the vehicle weight, the vehicle weight determined by the same being transmitted to the control unit as an input variable, and the control signal being determined within the control unit as a function of the vehicle weight determined.

The pamphlet DE 10 2009 034 003 A1 relates to a method for electromechanically adjusting a steering angle on at least one wheel axle of a motor vehicle. In order to increase the reliability when steering the motor vehicle, at least one value for a first variable on the motor vehicle is determined for calculating an electrical voltage which is provided for an electric power machine for adjusting the steering angle. The electrical voltage is then calculated from this value and at least one value for at least one other variable.

• - einer Lasterfassungseinrichtung zum Erfassen einer Grundlast, die auf die lenkbaren Fahrzeugräder einwirkt;
• - einer Einstelleinrichtung, die dafür vorgesehen ist, die Lenk-Unterstützungskraft des Servolenkungssystems einzustellen;
• - einer Steuereinrichtung zum Steuern der Aktion der Einstelleinrichtung auf der Basis der Grundlast, die von der Lasterfassungseinrichtung erfasst wird; und
• - einer Fahrzeugzustandserfassungseinrichtung zum Erfassen des Zustands des Fahrzeugs bezüglich des Fahrens und des Stillstandes des Fahrzeugs, wobei

die Steuereinrichtung eine erste Einstellzeit und eine zweite Einstellzeit, die kürzer ist als die erste Einstellzeit, einstellt, das Detektions-Ausgangssignal der Lasterfassungseinrichtung speichert und festhält, und wenn die Steuereinrichtung auf der Basis des Detektions-Ausgangssignals der Fahrzeugzustandserfassungseinrichtung den Start des Fahrzeugs nach der ersten Einstellzeit nach dem Erfassen eines Stillstandes des Fahrzeugs auf der Basis des Detektions-Ausgangssignals der Fahrzeugzustandserfassungseinrichtung feststellt, die Steuereinrichtung die Aktion der Einstelleinrichtung auf der Basis eines Grundlast-Detektions-Ausgangssignales steuert, das zur zweiten Einstellzeit vor dem Zeitpunkt des Erfassens des Starts des Fahrzeugs vorliegt.The pamphlet DE 196 80 331 B4 relates to a vehicle load dependent power steering system

• - A load detection device for detecting a basic load acting on the steerable vehicle wheels;
• - an adjustment device which is intended to adjust the steering assist force of the power steering system;
• - a control device for controlling the action of the adjustment device on the basis of the base load detected by the load detection device; and
• - a vehicle status detection device for detecting the status of the vehicle with respect to the driving and the standstill of the vehicle, wherein

the controller sets a first set time and a second set time shorter than the first set time, stores and holds the detection output of the load detector, and when the controller, based on the detection output of the vehicle state detector, starts the vehicle after the first setting time after detecting a standstill of the vehicle on the basis of the detection output of the vehicle state detection device, the control device controls the action of the setting device on the basis of a base load detection output signal which is present at the second setting time before the time of detecting the start of the vehicle .

The pamphlet WO 2015/082971 A1 relates to a parking assistance system that parks a vehicle at a target parking position by automatically steering an EPS. The parking assistance system comprises a detection unit that is configured to detect the vehicle position, a position determination unit that is configured to determine the target parking position, a generation unit that is configured to generate a path from the position of the vehicle to the target parking position, a detection unit that is for detecting the temperature of the EPS, and a support unit configured to automatically control the vehicle to move along the path generated by the generation unit.

The pamphlet DE 195 469 43 C1 relates to a steering system for non-track-bound vehicles, the transmission ratio between the adjustment paths of the steering handle and steering wheels being changed in accordance with a map depending on the driving speed and the adjustment paths of the steering handle or steering wheels.

The pamphlet DE 102 21 721 A1 relates to a motor vehicle with a steering system and a stop for limiting the maximum steering angle of the steerable vehicle wheel or wheels, the steering system containing an electronic control component with which the wheel steering angle can be influenced and with which a maximum possible Steering angle is determined and implemented as a function of at least one suitable boundary condition. The steering system has an electric or hydraulic actuator that can be controlled electronically in a suitable manner for influencing the wheel lock angle, with the size of the maximum lock angle being determined on the basis of the driving speed and/or the lateral acceleration or longitudinal acceleration of the vehicle, the loading condition of the vehicle and/or or the spring deflection of the steered wheel/wheels or can depend on typical operating conditions.

The invention is therefore based on the object of improving the positioning accuracy of assistance systems whose intervention takes place via the steering.

This object is achieved by a method having the features of claim 1 and by an assistance system having the features of claim 5. Preferred embodiments of the invention are the subject matter of the dependent claims.

• - Bestimmen des Beladungszustands des Kraftfahrzeugs,
• - Ermitteln eines Lenkwinkels und einer Lenkwinkelgeschwindigkeit unter Berücksichtigung des Beladungszustands, wobei das einen Eingriff in die Lenkung ausübende Assistenzsystem durch ein PLA (Parklenkassistent) gebildet wird, und
• - Einstellen des ermittelten Lenkwinkels und der Lenkwinkelgeschwindigkeit an der Lenkung.

The method according to the invention for compensating for the loading of a motor vehicle in an assistance system of the motor vehicle, the assistance system intervening in the steering of the motor vehicle carries out the following steps:

• - Determining the loading status of the motor vehicle,
• - Determination of a steering angle and a steering angle speed, taking into account the load condition, wherein the intervention in the steering exerting assistance system is formed by a PLA (park steering assistant), and
• - Setting the determined steering angle and the steering angle speed on the steering.

The assistance system preferably determines a steering torque, taking into account the load status, and applies the determined steering torque to the steering.

A loading sensor system preferably determines data on the loading of the motor vehicle and a device determines the loading state of the motor vehicle from the loading data.

More preferably, the loading condition of the motor vehicle is determined by the ESP system of the motor vehicle. In other words, the load sensors and the device for determining the load status are components of the ESP system.

In the case of a commercial vehicle, the compensation of the load status, for example in the case of a parking-steering assistant (PLA), has the advantage that the positioning accuracy of the PLA is increased, since higher steering forces can then be set to adjust the steering angle.

• - eine Beladungssensorik,
• - eine Einrichtung zur Ermittlung des Beladungszustands,
• - eine Steuereinrichtung zur Generierung der Assistenzfunktion, und
• - eine Aktorik zur Erzeugung der Assistenzfunktion.

The assistance system according to the invention of a motor vehicle, which intervenes in the steering of the motor vehicle, the assistance system being set up and designed to carry out the method explained above, comprises:

• - a load sensor,
• - a device for determining the loading status,
• - a control device for generating the assistance function, and
• - an actuator for generating the assistance function.

More preferably, the actuator generates a steering angle and/or a steering angle speed and/or a steering torque.

• 1 eine schematische Darstellung eines die Lenkung beeinflussenden Assistenzsystems, und
• 2 ein Beispiel einer Realisierung des Assistenzsystems in einem PLA-Assistenten.

A preferred embodiment of the invention is explained below with reference to the drawings. while showing

• 1 a schematic representation of an assistance system influencing the steering, and
• 2 an example of an implementation of the assistance system in a PLA assistant.

1 shows a schematic representation of an assistance system 1 of a motor vehicle, which intervenes in the steering of the vehicle. The steering intervention can consist of influencing the steering angle and/or applying a steering torque to the steering. The loading of the motor vehicle is determined by means of a loading sensor system 2 , with a device 3 determining the loading state of the motor vehicle from the data from the loading sensor system 2 . The information from device 3 about the load status of the motor vehicle is fed to a control device 4 for generating the assistance, which incorporates the load status information into the determination of a steering angle to be generated and/or a steering torque to be generated. The steering angle determined by the control device 4 is generated in the downstream actuator system 5 and/or the steering torque to be applied to the steering is generated in the downstream actuator system 6 .

The load status of a vehicle can be determined, for example, by the vehicle's own ESP system. In that case, the load sensor system 2 and the device for determining the load state would be part of the ESP system and the load state signal is fed to the control device 3 to generate the assistance for further processing. The control device 3 for generating the assistance function could be implemented by a parking/steering assistant, a lane keeping assistant (lane assist) or a DSR system (driver steering recommendation).

2 shows an implementation of the assistance system influencing the steering of a motor vehicle, taking into account the loading condition of the motor vehicle. The ESP 10 (Electronic Stability Program) determines the loading condition of the motor vehicle, which is transferred to an assistance system 11, which acts on the steering. The assistance system 11 influencing the steering can be implemented by a PLA (parking steering assistant), a lane assist (lane keeping assistant) or a DSR (driver steering recommendation), with the assistance system 11 determining the desired steering angle and/or the steering torque acting on the steering calculated. An actuator 12 then adjusts the steering angle determined by the assistance system 11 and/or applies the determined steering torque to the steering.

Reference List

1

assistance system

2

load sensors

3

Device for determining the load status

4

Control device for generating the assistance

5

Actuators for steering angle support

6

Actuators for steering torque support

10

ESP

11

PLA / LA / DSR

12

Actuators for generating the steering angle / the steering angle speed / the steering torque

Claims (6)

Method for compensating for the loading of a motor vehicle in an assistance system (1, 11) of the motor vehicle, wherein the assistance system (1, 11) intervenes in the steering of the motor vehicle, wherein a loading condition of the motor vehicle is determined, the assistance system determines a steering angle and a steering angle speed, taking into account the load status, the assistance system (11) intervening in the steering being formed by a PLA, and the determined steering angle and the steering angle speed are set on the steering. procedure after claim 1 , characterized in that the assistance system determines a steering torque taking into account the load condition, and the steering is acted upon by the steering torque determined. procedure after claim 1 or 2 , characterized in that a loading sensor system (2) determines data on the loading of the motor vehicle and a device (3) determines the loading condition of the motor vehicle from the loading data. Method according to one of the preceding claims, characterized in that the loading condition of the motor vehicle is determined by an ESP system (10). Assistance system (1, 11) of a motor vehicle, which intervenes in the steering of the motor vehicle, wherein the assistance system (1, 11) is set up and designed to carry out the method according to one of the preceding claims a load sensor system (2), a device (3) for determining the load status, a control device (4) for generating the assistance function, and an actuator (5, 6, 12) for generating the assistance function. assistance system claim 5 , characterized in that the actuator (5, 6, 12) generates a steering angle and/or a steering angle speed and/or a steering torque.

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