SE539938C2 - Method and system for adjusting the instantaneous speed of a vehicle in relation to the angular velocity of a steering wheel - Google Patents

Abstract

The present invention relates to a method for adjusting the speed of a vehicle when cornering. The method comprises the step of controlling (S1) the speed of the vehicle based on the steering wheel angle of the vehicle corresponding to a determined turning radius so that a predetermined lateral acceleration is not exceeded. The present invention also relates to a system for adjusting a vehicle's speed when cornering. The present invention also relates to a motor vehicle. The present invention also relates to a computer program and a computer program product.

Description

The invention relates to a method for adjusting a vehicle speed in cornering according to the preamble of claim 1. The invention relates to a system for adjusting a vehicle's speed when cornering. The invention also relates to a motor vehicle. The invention also relates to a computer program and a computer program product.

BACKGROUND When driving a heavy vehicle on a curvy and winding road surface, the driver must pay attention to the geometry of the road and the adaptation speed in order to drive the vehicle safely. Due to the curvature of the roadway, it can be difficult for the driver to anticipate future curves and take measures in good time for safe driving of the vehicle.

DE10258167 and EP2492160 show methods for controlling the speed of the vehicle in front of a curve based on curve shape and vehicle position.

When driving the vehicle in a curve, acceleration of the vehicle in the curve could cause strong lateral accelerations with the result that the vehicle drives off the road or inadvertently crosses into an adjacent lane. Consequently, the driver could achieve acceleration in the curve by the driver giving gas or by the vehicle's cruise control resumed previously set cruise control speed in a curve, for example by an accidental resumption of the cruise control in a roundabout, accelerating the vehicle in the curve could cause an accident.

OBJECT OF THE INVENTION An object of the present invention is to provide a method and system for adjusting the speed of a vehicle in cornering which enables improved safety.

SUMMARY OF THE INVENTION These and other objects, which appear from the following description, are achieved by means of a method, a system, a motor vehicle, a computer program and a computer program product of the kind initially stated and further having the features set forth in the appended independent claims. Preferred embodiments of the method and system are defined in the appended dependent claims.

According to the invention, the objects are achieved with a method for controlling the speed of a vehicle when cornering, comprising the step of controlling the speed of the vehicle based on the steering wheel angle of the vehicle corresponding to a predetermined turning speed so that a predetermined lateral acceleration is not exceeding the maximum speed. . In this case, it is avoided that the driver is allowed to accelerate too much or resumes previously set cruise control speed in a curve. Consequently, the safety of cornering is improved, thereby reducing the risk of skidding or skidding in the curve. With such a solution, good safety when cornering can be achieved without map data or equivalent means for determining future curvature along the vehicle's route for adjusting the speed when cornering. _. This enables a more correct determination of the vehicle's current turning radius and thus a better basis for controlling the vehicle's speed when driving the vehicle in a curve.

According to one embodiment, the method comprises the step of allowing an increase of the maximum permissible instantaneous speed only after a certain time after the angular speed has fallen below a predetermined value. This prevents the vehicle from accelerating too early after a first curve in order to avoid the vehicle having time to accelerate too much on a subsequent second curve.

According to one embodiment of the method, the step of limiting the increase of the maximum permissible instantaneous speed based on the angular velocity of the steering wheel stroke takes place only at steering wheel strokes over a predetermined size. This avoids unnecessary limitation of the speed at smaller steering angles.

The embodiments of the system have the same advantages as the corresponding embodiments of the method mentioned above.

DESCRIPTION OF THE DRAWINGS The present invention will be better understood with reference to the following detailed description read in conjunction with the accompanying drawings, in which like reference numerals refer to like parts throughout the many views, and in which: Fig. 1 schematically illustrates a motor vehicle according to an embodiment of the present invention; invention; Fig. 2 schematically illustrates a system for adjusting the speed of a vehicle in cornering according to an embodiment of the present invention; Fig. 3 schematically illustrates a block diagram of a method of pre-adjusting the speed of a vehicle in cornering according to an embodiment of the present invention; and Fig. 4 schematically illustrates a computer according to an embodiment of the present invention.

DESCRIPTION OF EMBODIMENTS Here, the term "link" refers to a communication link which may be a physical line, such as an opto-electronic communication line, or a non-physical line, such as a wireless connection, for example a radio or microwave link k.

Here, the term "effective wheelbase" refers to the virtual distance between the axles of the intermediate vehicle that best corresponds to a simplified representation of an "efficient wheelbase" reality. For a two-axle truck, the effective wheelbase = wheelbase, two-axle vehicle. The term means a simplification dept. the distance between the shoulders. For a vehicle that also includes a single-axle axle adjacent to and at a distance from a rear drive axle, the efficient wheelbase will be moved to somewhere midway between the support axle and the driveshaft, but not necessarily exactly between, the position of the efficient wheelbase depends on several factors such as weight distribution control. , etc. The purpose of an efficient wheelbase is to be able to consider a multi-axle vehicle as a two-axle vehicle to simplify the dynamic calculations according to the bicycle model.

Fig. 1 schematically illustrates a motor vehicle 1 according to an embodiment of the present invention. The exemplary vehicle 1 consists of a heavy vehicle in the form of a truck. The vehicle can alternatively consist of any suitable vehicle such as a bus or a car. The vehicle comprises a system I according to the present invention.

Fig. 2 schematically illustrates a block diagram of a system I for adjusting the speed of a vehicle in cornering according to an embodiment of the present invention. The system I comprises an electronic control unit 100.

System I includes means 110 for controlling the speed of the vehicle based on the steering angle of the vehicle corresponding to a determined turning radius so that a predetermined lateral acceleration is not exceeded.

The vehicle speed control means includes means 110a for determining a maximum allowable instantaneous speed based on the vehicle parameters: said predetermined lateral acceleration, denominator steering angle, effective wheelbase, steering gear and, where applicable, the vehicle understeer gradient.

The means 110a for determining a maximum permissible instantaneous speed includes means 111 for determining a maximum permissible lateral acceleration a / af. The means 111 for determining a maximum permissible lateral acceleration comprises determining a predetermined maximum permissible lateral acceleration, which is based on normal conditions regarding vehicle characteristics such as vehicle length, vehicle width, vehicle composition, vehicle load distribution and vehicle center of gravity or center of gravity. , friction characteristics of the road surface, visibility conditions, and dosing characteristics of the road surface. The predetermined maximum allowable side acceleration is according to one embodiment in the order of 2 m / s2. The maximum permissible lateral acceleration here consists of a predetermined maximum permissible lateral acceleration. According to an alternative or complementary variant, the electronic control unit 100 includes stored data on the maximum allowable lateral acceleration.

The means 110a for determining a maximum permissible instantaneous speed includes means 112 for determining the steering angle ö. The means 112 for determining the steering angle is arranged for continuously determining the steering angle. The means 112 for determining the steering wheel angle comprises sensor means in the form of steering wheel angle sensors for sensing the position of the steering wheel corresponding to a certain steering wheel angle.

The means 110a for determining a maximum permissible instantaneous speed includes means 113 for determining effective wheelbase L. The means 113 for determining effective wheelbase includes determining vehicle characteristics including distance between wheel axles, number of wheel axles, possible occurrence of boogie and possible presence of support axle and support axle. whether the support wheels of the support axle are brought into engagement with the roadway or are raised so that the support wheels are in non-contact with the roadway. The effective wheelbase is taxed on the basis of e.g. wheelbase, bogie distance, number of axles, weight distribution, reversing axle is hoisted, etc. According to an alternative or complementary variant, the electronic control unit 100 includes stored data on efficient wheelbase.

The means 110a for determining a maximum allowable instantaneous speed includes means 114 for determining the gear ratio iL. The means 114 for determining the gear ratio of the control comprises, according to a variant, stored data the gear ratio which is normally known. The means for determining the gear ratio comprises sensor means for determining the gear ratio by measuring input and output steering wheel angular velocity. According to an alternative or complementary variant, the electronic control unit 100 includes stored data on the control gear ratio.

The means 110a for determining a maximum permissible instantaneous speed includes means 115 for determining the understeer gradient KUS of the vehicle. The means 115 for determining the understeer gradient of the vehicle comprises sensor means for determining the understeer gradient of the vehicle and calculation models where the understeer gradient is determined based on, among other things, steering angle, effective wheelbase, vehicle speed, incoming and outgoing steering angle speed, gear speed and curvature of the roadway. According to an alternative or complementary variant, the electronic control unit 100 includes stored data on the understeer gradient of the vehicle.

The means 110a for determining a maximum permissible instantaneous speed based on the vehicle parameters: predetermined side acceleration, steering angle, effective wheelbase, steering gear and, where applicable, the vehicle understeer gradient are arranged to determine the maximum permissible instantaneous velocity a / equation: ie maximum allowable lateral acceleration.

L = effective wheelbase ear = steering wheel angle iL = steering gear ratio Cus = vehicle understeer gradient System I includes means 120 for continuously determining vehicle speed. The means 120 for continuously determining the speed of the vehicle includes, according to a variant, speedometer means.

System I includes means 130 for limiting the increase of the maximum permissible instantaneous speed based on the angular velocity of the steering wheel.

The means 130 for limiting the increase of the maximum permissible instantaneous speed based on the angular velocity of the steering angle comprises means 132 for determining the angular velocity of the steering angle. The means 132 for determining the angular velocity of the steering angle includes means for derivation including any filtering of the steering angle.

The means 132 for determining the angular velocity of the steering angle comprises means 132a for determining the size of the steering angle. System I here comprises means 132a for determining the size of the steering angle.

The means 130 for limiting the increase of the maximum permissible instantaneous speed based on the angular velocity of the steering angle comprises means 134 for limiting the increase only in the case of steering angle over a predetermined size.

System I includes means 140 for allowing increase of the maximum allowable time after the angular velocity has fallen below a predetermined value. The means 140 for allowing the instantaneous speed only after a predetermined increase of the maximum permissible instantaneous speed only after a predetermined time after the angular velocity has fallen below a predetermined value includes means for determining the time from the angular velocity below the predetermined value and for the predetermined time the the angular velocity has fallen below the predetermined value and until the angular velocity again reaches or exceeds the predetermined value.

The electronic control unit 100 is signal connected to the means 110 for controlling the speed of the vehicle based on the steering wheel angle of the vehicle corresponding to a predetermined turning radius so that a predetermined lateral acceleration is not exceeded by a link 10a. The electronic control unit 100 is arranged via the link 10 to send a signal to the means 110 representing control data for controlling the speed of the vehicle.

The electronic control unit 100 is signal connected to the means 110 for controlling the speed of the vehicle based on the steering wheel angle of the vehicle corresponding to a determined turning radius so that a predetermined lateral acceleration is not exceeded by a link 10b. The electronic control unit 100 is via the link 10b110 steering wheel angle data corresponding to a certain turning radius of the vehicle. arranged to receive a signal from the means representing The electronic control unit 100 is signal connected to the means 110a to determine a maximum permissible instantaneous speed based on the vehicle parameters: said predetermined lateral acceleration, denominator angle, effective wheelbase, steering gear and, if applicable, The electronic control unit 100 is arranged via the link 10 to receive a signal from the means 110 representing parameter data including side acceleration data predetermined side acceleration, steering wheel angle data for current steering angle, pre-effective wheelbase data, steering gear data and, if applicable, understeer gradient data.

The electronic control unit 100 is signal connected to the means 120 for continuously determining the speed of the vehicle via a link 20. The electronic control unit 100 is arranged via the link 20 to receive a signal from the means 120 for continuously determining the speed of the vehicle representing speed data for the current vehicle speed.

The electronic control unit 100 is signal connected to the means 132 for determining the angular velocity of the steering angle via a link 32. The electronic control unit 100 is arranged via the link 32 to receive a signal from the means 132 representing the angular velocity data of the steering angle including steering angle size 132.

The electronic control unit 100 is signal connected to the means 134 for limiting the increase of the maximum permissible instantaneous speed only in the event of a steering wheel stroke over a predetermined size via a link 34. The electronic control unit 100 is arranged via the link 34 to receive a signal from the means 134 representing limiting data to limit the increase only in the case of a steering wheel over a predetermined size.

The electronic control unit 100 is signal connected to the means 140 for allowing increase of the maximum permissible instantaneous speed only after a predetermined time after the angular speed has fallen below a predetermined value via a link 40a. The electronic control unit 100 is via the link 40 means 140 angular velocity data for angular velocity of steering angle including data for arranged to transmit a signal to representative size of steering angle.

The electronic control unit 100 is signal connected to the means 140 for allowing an increase of the maximum permissible instantaneous speed only after a predetermined time after the angular speed has fallen below a predetermined value via a link 40b. The electronic control unit 100 is arranged via the link 40 to receive a signal from the means 140 representing time data prematurely during which the angular velocity with a certain magnitude of the steering angle has fallen below a predetermined value.

The electronic control unit 100 is signal connected to the means 130 for limiting the increase of the maximum permissible instantaneous speed based on the angular velocity of the steering angle via a link 30a. The electronic control unit 100 is arranged via the link 30a to send a signal to the means 130 representing angular velocity data for angular velocity of steering wheel stroke, including data for the size of steering wheel stroke and time for such angular velocity.

The electronic control unit 100 is signal connected to the means 130 for limiting the increase of the maximum permissible instantaneous speed based on the angular velocity of the steering angle via a link 30b. The electronic control unit 100 is arranged via the link 30b to receive a signal from the means 130 representing speed limitation data based on angular velocity data.

The electronic control unit 100 is hereby arranged to process said steering angle data corresponding to a certain turning radius of the vehicle and said parameter data including side acceleration data for predetermined side acceleration, steering angle data for current steering angle, data for effective wheelbase data for steering gear ratio data and for example steering gear. control of the vehicle speed so that a predetermined lateral acceleration is not exceeded.

The electronic control unit 100 is hereby arranged to process said angular velocity data for angular velocity of steering wheel including data size of steering wheel stroke, said limiting data for limiting the increase only in steering angle over a predetermined size and said time data for time during which the angular velocity is predetermined to determine whether the angular velocity has exceeded a predetermined speed and predetermined size of steering wheel stroke and in that case, the transmission data limitation data is a limitation of the speed as long as this continues and a predetermined one after the angular velocity has fallen below a predetermined value.

Fig. 3 schematically illustrates a block diagram of a method for adjusting the speed of a vehicle in cornering according to an embodiment of the present invention.

According to one embodiment, the method for adjusting a vehicle speed during cornering comprises a step S1. In this step, the speed of the vehicle is controlled based on the steering wheel angle of the vehicle corresponding to a determined turning radius so that a predetermined lateral acceleration is not exceeded.

Referring to Fig. 5, a diagram of an embodiment of a device 500 is shown. The control unit 100 described with reference to Fig. 2 may in one embodiment comprise the device 500. The device 500 comprises a non-volatile memory 520, a data processing unit 510 and a read / write memory 550. 530 wherein a computer program, such as an operating system, is The non-volatile memory 520 has a first memory portion of the device 500. The device 500 further includes a bus controller, a serial communication port, I / O means, an A / D converter, a time and date input. and transfer unit, an event counter and an interrupt controller (not shown). The non-volatile memory 520 also has a second memory portion 540.

A computer program P is provided which includes routines for adjusting the speed of a vehicle when cornering according to the innovative method. The program P includes routines for controlling the speed of the vehicle based on the steering wheel angle of the vehicle corresponding to a certain turning radius so that a predetermined lateral acceleration is not exceeded. The program P can be stored in an executable manner or in a compressed manner in a memory 560 and / or in a read / write memory 550.

When it is described that the data processing unit 510 performs a certain function, it is understood that the data processing unit 510 performs a certain part of the program which is stored in the memory 560, or a certain part of the program which is stored in the read / write memory 550.

The data processing device 510 can communicate with a data port 599 via the data bus 515. The non-volatile memory 520 is intended for communication with the data processing unit 510 via a data bus 512. The separate memory 560 is intended to communicate with the data processing unit 510 via the data bus 511. the data processing unit 510 via a data bus unit 510. To the data port 599, the read / write memory 550 is arranged to communicate with e.g. the links connected to the control unit 100 are connected.

When data is received on data port 599, it is temporarily stored in the other540. When the data processing unit 510 is ready to perform execution of code on the memory part received input data has been temporarily stored, a mode as described above. The received signals on the data port 599 can be used by the device 500 to control the speed of the vehicle based on the steering wheel angle of the vehicle corresponding to a determined turning radius so that a predetermined lateral acceleration is not exceeded.

Parts of the methods described herein may be performed by the device 500 by means of the data processing unit 510 running the program stored in the memory 560 or read / write memory 550. When the device 500 runs the program, the methods described herein are executed.

The above description of the preferred embodiments of the present invention has been provided for illustrative and descriptive purposes. It is not intended to be exhaustive or to limit the invention to the described variants. Obviously, many modifications and variations will occur to those skilled in the art. The embodiments have been selected and described to best explain the principles of the invention and its practical applications, thereby enabling one skilled in the art to understand the invention for various embodiments and with the various modifications appropriate to the intended use.

Claims (1)

A method for adjusting-controlling the speed of a vehicle (1) when cornering, comprising the step of controlling (S1) the vehicle speed based on the steering wheel angle of the vehicle corresponding to a determined turning radius so that a predetermined lateral acceleration is not exceeded characterized by. permissible maximum speed angular velocityg of steering angle angle. limited based on 3e2. A method according to claim 13, comprising the step of allowing an increase of the maximum permissible mementana velocity only after a certain time after the angular velocity has fallen below a predetermined value. A method according to claim 13 or 24, wherein the step of limiting the increase of the maximum permissible mementana speed based on angular velocity of the steering wheel angle deflection occurs only in the case of steering wheel angle deflections above a predetermined size. 4. ä-System (I) for fl adjusting the speed of a vehicle (1) when cornering, comprising means (110) for controlling the speed of the vehicle based on the steering wheel angle of the vehicle corresponding to a determined turning radius so that a predetermined lateral acceleration is not exceeded. means (130) for limiting the increase of the maximum permissible speed based on angular velocity_e_n hose steering angle. 7-5. A system according to claim 58, comprising means (140) for allowing an increase of the maximum permitted speed only after a certain time after the angular speed has fallen below a predetermined value. A system according to claim 518 or §9, wherein the means (130) for limiting the maximum permissible increase based on the angular velocity of a steering wheel vinyl tee comprises means (132) for limiting the elevation only in the case of a steering angle tee over a predetermined size. SH. Vehicle (1) comprising a system (I) according to any one of claims Qê-Qw. 4 & § .__ Computer program (P) for adjusting the speed of a vehicle when cornering, wherein said computer program (P) comprises program code which, the deed is run by an electronic control unit (100) or another computer (500) connected to the electronic control unit (100), enables the electronic control unit (100) to perform the steps according to claim 1-§5. 44fi g._Computer program product comprising a digital storage medium which stores the computer program according to claim §4-2.