DE102009022170A1 - Driving speed regulating method for vehicle i.e. hybrid vehicle, involves providing maximally allowable driving speed, determining vehicle mass and regulating maximally allowable driving speed for region of road - Google Patents

Abstract

The method involves mathematically determining a maximally allowable driving speed based on a characteristic curve (K). The maximally allowable driving speed is provided based on gradient of a road lying ahead to a vehicle. Vehicle mass is determined based on a loading condition of the vehicle. The maximally allowable driving speed for a region of the road is regulated based on a momentary driving speed, road curvature, a road friction value, vehicle mass and a limit value for centripetal force which results from cornering. An independent claim is also included for a device for operating a driving speed regulation unit of a vehicle, comprising a detection unit.

Description

The The invention relates to a method for driving speed control a vehicle, wherein a maximum permissible driving speed depending on a course of the vehicle ahead route is given.

From the DE 199 52 392 A1 A method and apparatus for providing route-dependent driver information to a driver of a vehicle is known. In this case, a course of a distance to be traveled by the vehicle is determined at least in regions in a forward-looking manner and at least relative to the current vehicle position. A current driving state, for example a current driving speed or an acceleration, of the vehicle is ascertained, at least one limit condition for the driving state is determined, which enables a safe passage through an area of the route to be traveled ahead of the vehicle, and generates at least one route-dependent warning information, if the current driving condition does not meet the at least one boundary condition.

In addition, in the DE 198 48 236 A1 discloses a method and apparatus for limiting a speed of a vehicle. In the course of an iterative process, a setpoint speed is determined as a function of vehicle speed, maximum lateral acceleration and curve radius. The setpoint speed approaches a limit speed with which the curve to be traveled can be safely traversed. The vehicle speed is controlled depending on this target speed and an actual speed.

Of the Invention is based on the object, a relation to the State of the art improved method for driving speed control indicate, based on which a curve on a vehicle ahead Route can be passed safely.

The Task is according to the invention in terms of A method by the in claim 1 and in terms of the device solved by the features specified in claim 5. advantageous Further developments of the invention are the subject of the dependent claims.

The inventive method for driving speed control of a vehicle provides that a maximum allowable Driving speed depending on a course of a the route ahead of the vehicle. According to the invention the maximum permissible travel speed for at least an area of the route ahead in dependence a current driving speed, a curvature of the road, a road friction coefficient, a vehicle mass and a limit value for a resulting from cornering centripetal force regulated.

Based the process of the invention is in profit bringing a driving comfort for a vehicle occupant increased, since the maximum permissible driving speed depending on a resulting from cornering Transverse acceleration is determined and thereby acting on the vehicle occupant Centripetal force, also called transverse force, as not unpleasant becomes. For this purpose, the current driving speed of the vehicle delayed to the maximum permissible travel speed, the delay being particularly advantageous not done abruptly.

Next Increasing driving comfort and driving safety the fuel consumption of the vehicle is reduced because the driving speed of the vehicle in a particularly advantageous manner anticipatory regulated becomes.

About that In addition, driving safety is increased because the respective area the route ahead with an adjusted driving speed, the maximum permissible driving speed, is traversed.

embodiments The invention will be explained in more detail with reference to a drawing.

there shows:

1 schematically a program flowchart of the method according to the invention for driving speed control of a vehicle.

each other corresponding parts are in the figure with the same reference numerals Mistake.

In 1 a program flowchart of the method according to the invention for vehicle speed control of a vehicle is shown.

In particular, the method _{according to} the invention is initiated when a need for an intervention with regard to a current driving speed v _{Fzg of} the vehicle, in particular before cornering, is detected.

For this For example, the vehicle has one automatic cruise control device.

It is provided that by means of at least one detection unit E an environment identifier U of the vehicle, such as a camera, a radar sensor, a lidar and / or a photonic mixer, a distance ahead of the vehicle is detected.

alternative or additionally may be for detecting the vehicle ahead Route also a navigation system N can be used.

If the vehicle on the road ahead at least a curve ahead of the E of the environment recognition is located in the detection area of the detection unit U, are in an advantageous manner a road curvature c _0, hereafter referred to as curvature c ₀ denotes optionally a curve change of curvature c ₁ and a distance d detected at a Kurvenkurümmungspunkt and a signal processing S a control unit SE supplied.

Of the Curvature point denotes a so-called Vorschauort, where the forecast location in the distance d to the vehicle, in particular to the position of the detection unit E, the environment identifier U is located.

In addition, the instantaneous travel speed v _{Fzg of} the vehicle is determined as a further input variable for carrying out the method _according to the invention. The current driving speed V _Fzg can be _{read in} , for example via an engine control unit of the vehicle.

In the present _exemplary embodiment, the instantaneous driving speed v _{Fzg is,} in particular, a desired driving speed v _{Fzg set} which is predetermined for the speed control _{device of} the vehicle via the vehicle driver.

The detected signals with respect to the curvature of curve c ₀ , possibly the curvature change c ₁ and the distance d to the curvature point and the instantaneous _vehicle speed V _Fzg are the signal processing S supplied, wherein a sensor data fusion for predicting a curve is performed on the vehicle ahead route.

In the control unit SE, for example, in the control unit of the cruise control device, a characteristic field K is deposited, which at least a maximum permissible vehicle speed v _max as a function of the curve curvature c ₀ and a limit for a resulting from cornering with a corresponding curve curvature c ₀ centripetal force, ie a acting on a vehicle occupant lateral force F _Q , wherein the limit is hereinafter referred to as Grenzquerkraft F _{transverse, boundary} comprises.

Preferably the characteristic field K was empirically determined on the basis of driving tests.

mit
F_Q Querkraft,
m Fahrzeugmasse,
r Radius, wobei der Radius der Kehrwert der Kurvenkrümmung c₀ ist, und
v_Fzg momentane Fahrgeschwindigkeit.The lateral force F _Q acting on the vehicle, in particular on the vehicle occupants, can be determined, for example, as follows:

With
F _Q lateral force,
m vehicle mass,
r radius, wherein the radius of the reciprocal of the curvature c is ₀ , and
v _Vehicle current _vehicle speed.

Preferably, the characteristic field K further acts on a curve sizes, such. B. the vehicle mass m and / or a Fahrbahnreibwert k _my , with a possible procedure for determining the vehicle mass m and the Fahrbahnreibwertes k _my is described in more detail below.

If the determined instantaneous driving speed V _{Fzg of} the vehicle is less than a maximum permissible driving speed v _max dependent on the detected curve curvature or if the instantaneous driving speed v _{Fzg is} the same value as the maximum permissible driving speed v _max , then the driving speed control for cornering becomes corresponding the current driving speed V _Fzg regulated and / or controlled, wherein a delay a _{Fzg, delay} , ie a negative acceleration of the vehicle is 0.

In one possible embodiment of the method according to the invention, the maximum permissible driving speed v _max can be determined mathematically / physically as an alternative or in addition on the basis of the detected signals, which can be fed to an evaluation unit of the control unit SE, for example.

mit
v_max maximal zulässige Fahrgeschwindigkeit,
k_my Fahrbahnreibwert,
k(v_Fzg) fahrgeschwindigkeitsabhängiger Faktor,
F_{quer, Grenz} Grenzquerkraft,
m Fahrzeugmasse, und
c₀ Kurvenkrümmung.The maximum permissible travel speed v _max in relation to the forecast location at a distance d taking into account the vehicle mass m results, for example, from the following equation:

With
v _max maximum permissible travel speed,
k _my road friction coefficient,
k (v _veh ) vehicle speed dependent factor,
F _{quer, Grenz} Grenzquerkraft,
m vehicle mass, and
c ₀ curve curvature.

The driving speed-dependent lateral lateral force F _{transverse, limit} is determined by a driving-speed-dependent factor k (v _Fzg ) and, if appropriate, information relating to a road _{friction coefficient} k _my , which is determined, for example, by at least one detection unit E arranged on the vehicle.

Furthermore, the driving speed-dependent lateral lateral force F is _{transverse, limit} of the vehicle mass m dependent. A vehicle empty weight is specified as known and stored for example in the control unit SE, for example, the speed control device, wherein a load of the vehicle, for example by means arranged on an air suspension spring travel sensors and / or arranged on vehicle axles axle load sensors are determined or will. The vehicle mass m is thus determined preferably based on the vehicle idle weight plus the load of the vehicle.

Laying down the side load F _{transversely boundary} may be provided on the one hand that this is preset or it may alternatively be provided that the lateral limit force F _{transversely boundary} is chosen by the driver himself.

In one possible embodiment of the method according to the invention, when determining the lateral _{transverse force} F _{transverse, limit} , a center of gravity position and a resulting rolling motion of the vehicle can also be taken into account.

mit
a_{Fzg, Verzögerung} Verzögerung, negative Beschleunigung,
v_max maximal zulässige Fahrgeschwindigkeit,
v_Fzg momentane Fahrgeschwindigkeit, und
d Abstand des Fahrzeuges, insbesondere Abstand der Erfassungseinheit E der Umfelderkennung U zu dem Vorausschauort.If the value of the instantaneous driving speed v _Fzg does not correspond to the value of the maximum permissible driving speed v _max determined on the basis of the characteristic field K and / or the mathematical derivation, or is the value of the instantaneous driving speed v _Fzg greater than the maximum permissible driving speed v _max for the _vehicle Cornering, so the deceleration a _{Fzg, deceleration of} the vehicle, the negative acceleration, for example, determined by the following equation:

With
a _{vehicle, delay} delay, negative acceleration,
v _max maximum permissible travel speed,
v _Fzg instantaneous driving speed, and
d distance of the vehicle, in particular distance of the detection unit E of the surroundings identifier U to the preview location.

In this case, the deceleration a _{Fzg, deceleration represents} a function of the maximum permissible travel speed v _max for the _{forecast location} at a distance d and the instantaneous vehicle speed v _{Fzg of} the vehicle.

The determined value of the deceleration a _{Fzg, delay} is supplied to the control unit SE functional _interfaces for actuators SG, for example, a turn-off air compressor LV, a turn-off generator G and / or a device V for energy recovery, especially in a hybrid vehicle supplied.

In this case, the delay a _{Fzg, delay of} the vehicle in a particularly advantageous manner is not carried out abruptly.

The inventive method can be referred to as a predictive cruise control, the vehicle speed control, for example, by the driver for a straight ahead driving speed v _{Fzg, set} controls and / or regulates, and the current vehicle speed V _{Fzg of} the vehicle when cornering on the maximum for cornering permissible travel speed v _max delayed.

In a particularly advantageous manner, at the maximum permissible driving speed v _max, the lateral force F _Q acting on the vehicle driver from the cornering is taken into account, it being possible to provide that the lateral lateral force F _{transverse, limit is} predetermined or predetermined by a vehicle driver.

Based the method according to the invention is a driving safety as well as increased ride comfort, especially when cornering that a lane course in the longitudinal and lateral direction successively is predicted. The driving speed of the vehicle is anticipatory controlled and / or regulated, thereby reducing fuel consumption of the vehicle can be achieved.

In addition, information about the size of the delay a _{Fzg, delay} the current _vehicle speed v _Fzg also targeted for an active energy management, for example, from switchable ancillaries to operating _strategies of hybrid drives are used.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• DE 19952392 A1 [0002]
• - DE 19848236 A1 [0003]

Claims (5)

A method for driving speed control of a vehicle, wherein a maximum permissible driving speed (v _max ) is predetermined as a function of a course of the vehicle ahead route, characterized in that the maximum permissible driving speed (v _max ) for at least a portion of the route ahead at least in dependence current _vehicle speed (v _Fzg ), a road _curvature (c ₀ ), a road _{friction coefficient} (k _my ), a vehicle mass (m) and a limit value for a resulting from cornering centripetal force is controlled. A method according to claim 1, characterized in that the maximum permissible driving speed (v _max ) is determined based on a stored Kennlineinfeldes (K). A method according to claim 1 or 2, characterized in that the maximum permissible driving speed (v _max ) is determined mathematically. Method according to one of claims 1 to 3, characterized in that the vehicle mass (m) based on a Loading state of the vehicle is determined. Device for operating a vehicle speed control of a vehicle, wherein at least one detection unit (E) is provided, by means of which a vehicle ahead route can be detected, wherein detected signals of a control unit (SE) can be supplied and a maximum speed (v _max ) based on the detected Signals can be predetermined, characterized in that by means of at least one further detection unit (E) at least a current _vehicle speed (v _Fzg ), a road _curvature (c ₀ ), a Fahrbahnreibwert (k _my ) and a vehicle mass (m) detectable and the detected signals of the Control unit can be supplied, wherein the maximum permissible travel speed (v _max ) by means of the control unit (SE) based on the detected signals and a determined limit value for a resulting from cornering centripetal force is controllable.