WO2015178839A1

WO2015178839A1 - Method and system for adapting the acceleration of a vehicle during driving of the vehicle along a route of travel

Info

Publication number: WO2015178839A1
Application number: PCT/SE2015/050569
Authority: WO
Inventors: Jonny Andersson; Linus Bredberg
Original assignee: Scania Cv Ab
Priority date: 2014-05-21
Filing date: 2015-05-20
Publication date: 2015-11-26
Also published as: SE1450598A1; EP3145781A1; KR20170005065A; EP3145781A4; SE539599C2; BR112016024904A2

Abstract

The present invention concerns a method for adapting the acceleration of a vehicle (1 ) during driving of the vehicle along a route of travel. The method comprises the steps of: continuously determining (S1 ) the occurrence of velocity-limiting factors along the route of travel of the vehicle; and, in connection with the determination of a velocity-limiting factor, prescribing (S1 a) a velocity based on occurring velocity-limiting factors and determining (S2) the acceleration required to achieve the prescribed velocity at an occurring velocity-limiting factor. The step of determining the acceleration required to achieve the prescribed velocity at the occurring velocity-limiting factor comprises the step of continuously determining the driving resistance along the route of travel of the vehicle. The present invention also concerns a system. The present invention also concerns a motor vehicle. The present invention also concerns a computer program and a computer program product.

Description

METHOD AND SYSTEM FOR ADAPTING THE ACCELERATION OF A VEHICLE DURING DRIVING

OF THE VEHICLE ALONG A ROUTE OF TRAVEL

5 TECHNICAL FIELD OF THE INVENTION

The invention concerns a method for adapting the acceleration of a vehicle during driving of the vehicle along a route of travel according to the preamble to claim 1 . The invention concerns a system for adapting the acceleration of a vehicle during driving of the vehicle along a route of travel. The invention 10 also concerns a motor vehicle. The invention also concerns a computer

program and a computer program product.

BACKGROUND

Cruise controls and similar driver aids are becoming more and more 15 intelligent. Today there is a plurality of systems on the market that make use of cartographic data to drive the vehicle in a fuel-efficient manner. These systems are, however, adapted so as to take into account only the appearance of the topography, which, in practice, makes them functions that are suitable for use on motorways and corresponding roads.

20 Current systems are based entirely on a preset setpoint velocity. The topology-based cruise controls are allowed to deviate from same by only a certain percentage or km/h. If the vehicle in question drives onto a smaller road with curves and velocity limitations, it is appropriate to turn off the cruise control, as the driver himself will need to brake in advance of any curve. On

25 smaller roads with many curves it is also difficult for a driver to drive optimally from the standpoint of fuel economy. This is because it is often difficult to see what is happening around the next curve. OBJECT OF THE INVENTION

One object of the present invention is to provide a method and a system for adapting the acceleration of a vehicle during driving of the vehicle along a route of travel that enables safe and comfortable driving in connection with velocity-limiting factors.

SUMMARY OF THE INVENTION

These and other objects, which are presented in the description below, are achieved by means of a method, a system, a motor vehicle, a computer program and a computer program product of the types specified above, and which further exhibit the features specified in the characterizing part of the accompanying independent claims. Preferred embodiments of the method and the system are defined in the accompanying non-independent claims.

According to the invention, these objects are achieved by means of a method for adapting the acceleration of a vehicle during driving of the vehicle along a route of travel, comprising the steps of: continuously determining the occurrence of velocity-limiting factors along the route of travel of the vehicle; and, in connection with the determination of a velocity-limiting factor, prescribing a velocity based on the occurring velocity-limiting factor and determining the acceleration required to achieve said prescribed velocity at the occurring velocity-limiting factor. The step of determining the acceleration required to achieve the prescribed velocity at the occurring velocity-limiting factor further comprises the step of continuously determining the driving resistance along the route of travel of the vehicle. The acceleration of the vehicle is suitable adapted to correspond to the determined required acceleration, so that the prescribed velocity is achieved at the position/time of the velocity-limiting factor. Safe and comfortable driving of the vehicle in connection with velocity-limiting factors is hereby enabled. Adapting the acceleration in order to achieve the prescribed velocity so that fuel-efficient driving and a trade-off between performance and fuel economy is also enabled hereby in dependence upon how far before the velocity-limiting factor the required acceleration limitation is initiated. According to one embodiment of the method, the step of determining the acceleration required to reach the prescribed velocity at an occurring velocity-limiting factor occurs continuously. Determining the required acceleration continuously ensures that the prescribed velocity is reached in a safe and comfortable manner. Such continuous determination further ensures that no required acceleration is lost in the form of retardation. The prescribed velocity is preferably based on the determined velocity- limiting factor. Different velocity-limiting factors thus entail different prescribed velocities. The prescribed velocity can be viewed as a target velocity that is strived for. According to one embodiment of the method, said velocity-limiting factors include the curvature of the route of travel, wherein the prescribed velocity is prescribed based on the maximum permissible lateral acceleration of the vehicle. Safe driving of the vehicle is thus enabled, in that its velocity is adapted when taking curves.

According to one embodiment of the method, said velocity-limiting factors include changes in velocity limitation along the route of travel of the vehicle. The prescribed velocity is thus prescribed based on the changed velocity limitation. The prescribed velocity preferably consists of the upcoming changed velocity limitation. It is ensured hereby that adaptation to velocity limitations along the route of travel of the vehicle will occur in a safe and comfortable manner. Continuously determining the driving resistance along the route of travel of the vehicle enables determination of a more correct required acceleration. More fuel-efficient driving of the vehicle is further enabled in that, for example, hills can be used for coasting, whereupon both unnecessary braking of acceleration in the form of retardation and unnecessary applying of the accelerator for positive acceleration can be avoided. According to one embodiment of the method, the step of continuously determining the occurrence of velocity-limiting factors along the route of travel of the vehicle occurs based on a predetermined distance- and/or time horizon ahead of the vehicle along the route of travel of the vehicle. This makes it possible to adapt the acceleration in the form of retardation, taking into account performance and fuel economy in dependence upon how far before the velocity-limiting factor the required acceleration limitation is initiated, i.e. in dependence upon the distance- and/or time horizon ahead of the vehicle along the route of travel of the vehicle. According to one embodiment, the method comprises the step of prescribing a velocity in the form of a velocity profile along the route of travel of the vehicle and continuously executing said velocity profile by means of continuously determining said required acceleration. The possibilities in terms of safe and comfortable driving of the vehicle in connection with velocity-limiting factors are further improved hereby.

The embodiments of the system exhibit advantages corresponding to those of the corresponding embodiments of the method cited above.

FIGURE DESCRIPTION

The present invention will be better understood with reference to the following detailed description read in conjunction with the accompanying drawings, wherein the same reference designations refer to the same parts consistently in the many views, and in which:

Fig. 1 schematically illustrates a motor vehicle according to one embodiment of the present invention; Fig. 2 schematically illustrates a system for adapting the acceleration of a vehicle during driving of the vehicle along a route of travel according to one embodiment of the present invention;

Fig. 3a schematically illustrates a curvature profile; Fig. 3b schematically illustrates velocity profiles for the curvature profile in Fig. 3a;

Fig. 4 schematically illustrates a block diagram of a method for adapting the acceleration of a vehicle during driving of the vehicle along a route of travel according to one embodiment of the present invention; and

Fig. 5 schematically illustrates a computer according to one embodiment of the present invention.

DESCRIPTION OF EMBODIMENTS The term "link " refers herein to a communication link, which can 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.

The term "acceleration" refers herein to both positive and negative acceleration, i.e. acceleration in the form of increasing velocity and acceleration in the form of reduced velocity, i.e. retardation.

The term "continuously determine" refers herein, for example in connection with "continuously determining the acceleration required to achieve a prescribed velocity in connection with an occurring velocity-limiting factor," to non-incremental determination or incremental determination, i.e. where the determination occurs with a at repeated frequency that can be regular, and that can be time-based or distance-based.

The term "velocity-limiting factors" refers herein to any arbitrary factors along the route of travel of the vehicle that entail that a velocity limitation of the vehicle is called for. "Velocity-limiting factors" include the curvature along the route of travel of the vehicle. "Velocity-limiting factors" include the speed limit along the route of travel of the vehicle. "Velocity-limiting factors" could also include other factors such as a narrowing road, roadwork along the route of travel of the vehicle, obstacles such as speed bumps along the route of travel of the vehicle, a degraded road surface, increased traffic density/risk of congestion etc. Fig. 1 schematically illustrates a motor vehicle 1 according to one embodiment of the present invention. The exemplary vehicle 1 consists of a heavy vehicle in the form of a goods vehicle. The vehicle can alternatively consist of any arbitrary suitable vehicle, such as a bus or a car. The vehicle contains a system I according to the present invention. Fig. 2 schematically illustrates a block diagram of a system I for adapting the acceleration of a vehicle during driving of the vehicle along a route of travel according to one embodiment of the present invention.

The system I comprises an electronic control unit 100.

The system I comprises means 1 1 0 for continuously determining the occurrence of velocity-limiting factors along the route of travel of the vehicle.

Said velocity-limiting factors can include the curvature of the route of travel. Said velocity-limiting factors can include changes in velocity limitation along the route of travel of the vehicle.

According to one variant, the means 1 10 for continuously determining the occurrence of velocity-limiting factors along the route of travel of the vehicle comprise a cartographic information unit 1 12 containing cartographic data comprising characteristics of the roadway along the route of travel of the vehicle, including velocity-limiting factors in the form of curvature and changes in velocity limitation along the route of travel of the vehicle. According to one variant, the means 1 10 for continuously determining the occurrence of velocity-limiting factors along the route of travel of the vehicle comprise means 1 14 for determining the vehicle position. The means 1 14 for determining the vehicle position comprise a geographic positioning system for continuously determining the vehicle position along the route of travel. An example of a geographic positioning system can be GPS.

According to one variant, the cartographic information unit 1 1 2 and the means 1 14 for determining the vehicle position comprise means 1 10a for determining the route of travel of the vehicle, wherein the means for determining the route of travel of the vehicle are arranged so as to provide predetermined characteristics of the roadway along the route of travel of the vehicle comprising velocity-limiting factors in the form of the curvature of and changes in velocity limitation along the route of travel of the vehicle. Said cartographic data in the cartographic information unit 1 12 also include characteristics of the roadway along the route of travel of the vehicle comprising its topography.

The cartographic information unit 1 12 and the means 1 14 for determining the vehicle position consequently make it possible to continuously identify the vehicle position and characteristics of the roadway comprising velocity- limiting factors in the form of the curvature and changes in velocity limitation along the route of travel of the vehicle.

According to one variant, the means 1 10 for continuously determining the occurrence of velocity-limiting factors along the route of travel of the vehicle comprise a camera element 1 16. The camera element 1 1 6 is arranged so as to detect characteristics of the roadway comprising velocity-limiting factors in the form of the curvature and changes in velocity limitation along the route of travel of the vehicle. The camera element 1 16 is arranged so as to detect the conformation of the widening of the road comprising bends in the roadway and/or road markings in order to thereby determine bends in the roadway along which the vehicle is traveling. The camera element 1 16 is arranged so as to detect road signs along the route of travel of the vehicle comprising speed limit signs, wherein the camera element 1 16 is arranged so as to determine changes in velocity limitation along the route of travel of the vehicle by sensing speed limit signs. The camera element can comprise one or more cameras for such detection.

According to one variant, the means 1 10 for determining the occurrence of velocity-limiting factors along the route of travel of the vehicle comprise communication means for communication between the vehicle and other vehicles or the vehicle and other entities in order to communicate velocity- limiting factors such as the start of congestion or the like.

The means 1 10 for continuously determining the occurrence of velocity- limiting factors along the route of travel of the vehicle include means for performing said determination based on a predetermined distance- and/or time horizon ahead of the vehicle along the route of travel of the vehicle.

According to one embodiment, the means 1 10 for continuously determining the occurrence of velocity-limiting factors along the route of travel of the vehicle comprise means for performing said determination based on a predetermined distance horizon ahead of the vehicle along the route of travel of the vehicle, wherein the distance horizon consists of a suitable window in the form of a distance from the current vehicle position and forward along the route of travel of the vehicle. According to one embodiment, the distance horizon is on the order of several hundred meters, e.g. roughly 500 meters. According to one variant, the distance horizon is dependent upon the vehicle velocity. According to one variant, the distance horizon is dependent upon considerations of comfort, considerations of fuel economy and considerations of driving efficiency, i.e. how time-efficient the driving of the vehicle is. Setting the distance horizon relatively shorter thus entails that a more rapid negative acceleration/retardation is required in connection with the occurrence of a velocity-limiting factor, which enables more time-efficient driving of the vehicle. Setting the distance horizon relatively longer thus entails a slower negative acceleration/retardation in connection with the occurrence of a velocity-limiting factor, which enables more comfortable and/or fuel-efficient driving.

According to one variant, the system comprises means 1 20 for adjusting the desired distance horizon for the desired driving of the vehicle, wherein the desired distance horizon corresponds to the desired driving mode, such as an economy mode, comfort mode or high-power mode. According to one embodiment, the means for adjusting the desired distance horizon comprise control elements for such adjustment.

The system I comprises means 130 for continuously determining the vehicle velocity. According to one variant, the means 1 30 for continuously determining the vehicle velocity comprise velocity-measuring elements.

The system I comprises means 140 for determining the acceleration required in connection with a determined velocity-limiting factor to achieve the prescribed velocity in connection with the occurrence of a velocity-limiting factor.

The means 140 for determining the acceleration required to achieve the prescribed velocity in connection with the occurrence of a velocity-limiting factor are arranged for continuous determination. A velocity profile that is more suitable from a driving standpoint can be achieved by continuously determining the acceleration required to achieve the prescribed velocity in connection with the occurrence of a velocity-limiting factor.

According to one variant, the means 140 for determining the acceleration required to achieve the prescribed velocity in connection with an occurring velocity-limiting factor based on a predetermined distance horizon ahead of the vehicle along the route of travel of the vehicle function based on the following equations:

1) t^? = -^fo + a * r Here, v is the velocity that corresponds to the prescribed velocity in connection with an occurring velocity-limiting factor, v₀ the current velocity, a the required acceleration and ί the time to the position of the velocity-limiting factor. Equation 1 ) applies based on a time horizon. The required acceleration a can thus be determined based on the prescribed velocity v, current velocity v₀ and the time t until the occurrence of the velocity-limiting factor. In calculations where the determination is made based on a predetermined distance horizon, t(s) needs to be solved for according to equation 2): 2) ^" a

The distance s is derived from: * t²

3) * = +—

Inserting equation 2) into equation 3) and solving, the acceleration a is obtained:

..._;2 _ „,2

4) ^{il ~} 2 * s

Where v₀ is consequently the current velocity, i.e. the velocity at the start of the simulation, and v is the prescribed velocity according to the velocity- limiting factor occurring after the distance s. The required acceleration a can thus be determined based on the prescribed velocity v, the current velocity v₀ and the distance s to the velocity-limiting factor.

The means 140 for determining the acceleration required to achieve the prescribed velocity in connection with an occurring velocity-limiting factor comprise means 142 for continuously determining the driving resistance along the route of travel of the vehicle. The means 142 for continuously determining the driving resistance along the route of travel of the vehicle suitably comprise means 142a for determining grade resistance. The means 142a for determining grade resistance comprise or are comprised in means for determining the topology along the route of travel of the vehicle, i.e. any grade of the roadway along the route of travel of the vehicle.

According to one variant, the means 142a for determining the grade resistance comprise a cartographic information unit containing cartographic data comprising characteristics of the roadway along the route of travel of the vehicle, including the topology along the route of travel of the vehicle, and means for determining the vehicle position which, according to one variant, comprise a geographic positioning system, such as GPS, for continuously determining the vehicle position along the route of travel. According to one variant, the cartographic information unit and the means for determining the vehicle position consist of the cartographic information unit 1 1 2 and the means 1 14 for determining the vehicle position.

The means 142 for continuously determining the driving resistance along the route of travel of the vehicle comprise suitable means 142b for determining friction characteristics of the vehicle drive train. The means 142b for determining friction characteristics of the vehicle drive train comprise means for determining speed differences between the wheels during driving/braking, so called "slip". Slip is determined by determining speed differences between the wheels. For instance, in that sensor elements measure the rotational speed of the wheels. The means 142 for continuously determining the driving resistance along the route of travel of the vehicle suitably comprise means 142c for determining air resistance. The means 142c for determining air resistance comprise modeling means for estimating the air resistance based on an air resistance coefficient and vehicle characteristics comprising its frontal area and the square of the vehicle velocity. According to one variant, the means 142c for determining the air resistance comprise a sensor element for measuring the air striking the vehicle, taking into account the vehicle geometry, including air deflectors for reducing air resistance.

The means 142 for continuously determining the driving resistance along the route of travel of the vehicle suitably comprise means 142d for measuring rolling resistance. The means 142d for determining rolling resistance comprise modeling means for estimating the rolling resistance by means of vehicle characteristics comprising the number of axles on the vehicle, the vehicle weight, the road surface and, in applicable cases, the tire type. The means 142 for determining the driving resistance F_res comprise calculating means. According to one variant, the calculating means are arranged so as to determine a mean value for the acceleration contribution, a_reSav_g that the driving resistance generates over a current distance horizon s. The distance horizon s can be the distance from the vehicle to the occurring velocity-limiting factor. This occurs in accordance with:

½^■ res Ά> -^Α,;>

5) ^a' -^ ^~ 77n.

The total required acceleration a_tof that is required will thus be:

6) ^ateti^s) - ^a + Qresasrs = 2 * s S * m

The required acceleration can thus be determined based on an average driving resistance. Unnecessary retarding of the vehicle can thus be avoided.

According to one variant, the means 140 for determining the acceleration required to achieve the prescribed velocity in connection with an occurring velocity-limiting factor comprise means for determining the required brake retardation. The required brake retardation a_brake is determined in corresponding fashion according to:

where, according to one variant, v_brake could be a modified prescribed velocity/target velocity. Based on the latter max expression max(0, a_resavg), any braking force from the driving resistance is utilized in an effective manner, and braking does not occur unnecessarily.

Vbrake is used to be able to differentiate between the prescribed velocity v and the braking velocity, i.e. a vehicle velocity that necessitates braking action. The prescribed velocity v can consist of a reference velocity. For example, the reference velocity is set to 50 km/h before a 50km/h stretch, but a downhill section will cause the vehicle to roll to a velocity of over 50 km/h. The braking velocity V_brake can then be set to, for example, 60 km/h, so that the vehicle is allowed to roll, and brake activation will not occur until the vehicle reaches 60 km/h, resulting in more fuel-efficient driving of the vehicle.

The system I comprises means 150 for determining the maximum permissible lateral acceleration. The means 150 for determining the maximum permissible lateral acceleration comprise the determination of a predetermined maximum permissible lateral acceleration, which is based on normal conditions with respect to vehicle characteristics, such as the length of the vehicle, width of the vehicle, carriage of the vehicle, load distribution of the vehicle, weight distribution of the vehicle, axle pressure of the vehicle and/or environmental characteristics such as the effective lane width, friction characteristics of the roadway, visibility conditions and the slope characteristics of the roadway. According to one embodiment, the predetermined maximum permissible lateral acceleration is on the order of 2 m/s². The maximum permissible lateral acceleration here consists of a predetermined maximum permissible lateral acceleration. According to one alternative, or complementary, variant, the electronic control unit 100 contains stored data pertaining to the maximum permissible lateral acceleration. The system I comprises means 160 for prescribing velocity based on velocity-limiting factors occurring along the route of travel of the vehicle. The means 1 60 for prescribing velocity based on velocity-limiting factors occurring along the route of travel of the vehicle suitably comprise means 162 for prescribing a velocity based on the maximum permissible lateral acceleration of the vehicle. The means 162 for prescribing velocity based on the maximum permissible lateral acceleration of the vehicle comprise the determination of a maximum vehicle velocity based on the maximum permissible lateral acceleration. The prescribed velocity thus corresponds to the maximum vehicle velocity. "Vehicle velocity" refers here to longitudinal vehicle velocity.

The means 160 for prescribing velocity based on velocity-limiting factors occurring along the route of travel of the vehicle suitably comprise means 164 for prescribing velocity based on changes in velocity limitation along the route of travel of the vehicle.

The system I comprises means for prescribing velocity in the form of a velocity profile along the route of travel of the vehicle. According to one embodiment, the means 1 60 for prescribing velocity based on velocity- limiting factors occurring along the route of travel of the vehicle comprise the means for prescribing velocity in the form of a velocity profile along the route of travel of the vehicle. The means 160 are consequently arranged so as to prescribe velocity in the form of a velocity profile along the route of travel of the vehicle.

The system I further comprises means for continuously executing said prescribed velocity profile by continuously determining said required acceleration. According to one embodiment, the means 1 60 for prescribing velocity based on velocity-limiting factors occurring along the route of travel of the vehicle comprise the means for continuously executing said velocity profile by continuously determining said required acceleration. The means 160 are consequently arranged so as to continuously execute said velocity profile by continuously determining said required acceleration.

The determination of the maximum vehicle velocity and thus the prescribed velocity/velocity profile based on the maximum permissible lateral acceleration utilizes information about the curvature of the roadway along the route of travel of the vehicle, wherein the following equation A) is utilized:

where v_max(s) is the maximum velocity on the stretch s ahead of the vehicle and aia max(s) the maximum permissible lateral acceleration on the stretch s ahead of the vehicle, while c(s) is the curvature of the stretch s ahead of the vehicle.

According to one variant, the system I comprises means 170 for determining whether an initial required acceleration determined by means of the means 140 is negative, i.e. requires retardation of the vehicle, or positive, i.e. requires a velocity increase in the form of positive acceleration, wherein the means 170 also include taking into account whether the initial acceleration, a_now is negative or positive, and thereby differentiating between negative and positive initial required acceleration. According to one variant, this can occur according to: i) The initial acceleration request is negative

< - a s))

ii) The initial acceleration request is positive fi_¾11, = sat(.inln (a„_5W„ a(s)^').. 0,13)

A positive initial acceleration request according to ii) means that the vehicle will initially increase its velocity. The means 170 are arranged so as, in the event that a velocity-limiting factor arises within a predetermined time that is relatively short, and wherein negative acceleration is required to reach it, depending on the current situation, to instead ensure that the current velocity is maintained, and to instead wait for this velocity decrease in order to thus avoid accelerating in cases where it is known that it will be necessary to brake in a short time. For example, a_mw could be determined according to ii) over a predetermined distance that is shorter than the distance horizon, wherein such a predetermined distance is on the order of 50 m according to one variant. In the event that a velocity reduction is required in order to cope with a velocity-limiting factor within, for example, 100 m or 5 seconds, the acceleration can still be set to 0 up until the need for negative acceleration becomes great enough that engine braking becomes necessary.

The electronic control unit 100 is in signal communication with the means 1 10 for determining the occurrence of velocity-limiting factors along the route of travel of the vehicle via a link 10. The electronic control unit 100 is arranged so as to receive, via the link 10, a signal from the means 1 1 0 representing data for velocity-limiting factors such as curvature and/or changes in velocity limitation.

The electronic control unit 100 is in signal communication with the means 1 10a comprising the cartographic information unit 1 12 and the means 1 14 for determining the vehicle position via a link 10a. The electronic control unit 1 00 is arranged so as to receive, via the link 10a, a signal from the means 1 10a representing cartographic data for velocity-limiting factors in the form of curvature and changes in velocity limitation along the route of travel of the vehicle, and position data for the position of the curvature relative to the vehicle.

The electronic control unit 100 is in signal communication with the camera element 1 16 via a link 16. The electronic control unit 100 is arranged so as to receive, via the link 16, a signal from the camera element 1 16 representing data for velocity-limiting factors comprising curvature data for the curvature of the roadway along the route of travel of the vehicle and data for changes in velocity limitation along the route of travel of the vehicle.

The electronic control unit 100 is in signal communication with the means 120 for adjusting the desired distance horizon for the desired driving of the vehicle via a link 20. The electronic control unit 100 is arranged so as to receive, via the link 20, a signal from the means 1 20 representing data for the desired distance horizon.

The electronic control unit 100 is in signal communication with the means 130 for continuously determining the vehicle velocity via a link 30. The electronic control unit 100 is arranged so as to receive, via the link 30, a signal from the means 130 for continuously determining the vehicle velocity representing velocity data for the current vehicle velocity.

The electronic control unit 100 is in signal communication with the means 140 for determining, in connection with the determination of a velocity-limiting factor, the acceleration required to achieve the prescribed velocity in connection with the occurring velocity-limiting factor via a link 40a. The electronic control unit 100 is arranged so as to receive, via the link 40a, a signal from the means 140 representing acceleration data for the acceleration required to achieve the velocity for the occurring velocity-limiting factor at the velocity-limiting factor.

The electronic control unit 100 is in signal communication with the means 142 for continuously determining driving resistance along the route of travel of the vehicle via a link 42. The electronic control unit 100 is arranged so as to receive, via the link 42, a signal from the means 142 representing driving resistance data.

The electronic control unit 100 is in signal communication with the means 142a for determining grade resistance via a link 42a. The electronic control unit 100 is arranged so as to receive, via the link 42a, a signal from the means 142a representing grade data for the grade of the roadway along the route of travel of the vehicle.

The electronic control unit 100 is in signal communication with the means 142b for determining friction characteristics of the vehicle drive train via a link 42b. The electronic control unit 100 is arranged so as to receive, via the link 42b, a signal from the means 142b representing friction data for friction characteristics of the vehicle drive train.

The electronic control unit 100 is in signal communication with the means 142c for determining air resistance via a link 42c. The electronic control unit 100 is arranged so as to receive, via the link 42c, a signal from the means 142c representing air resistance data for the vehicle along the route of travel of the vehicle.

The electronic control unit 100 is in signal communication with the means 142d for determining rolling resistance via a link 42d. The electronic control unit 100 is arranged so as to receive, via the link 42d, a signal from the means 142d representing rolling resistance data for the vehicle along the roadway along the route of travel of the vehicle.

The electronic control unit 100 is in signal communication with the means 140 for determining, in connection with the determination of a velocity-limiting factor, the acceleration required to achieve the prescribed velocity for an occurring velocity-limiting factor via a link 40b. The electronic control unit 100 is arranged so as to send, via the link 40b, a signal to the means 140 representing velocity data for the current velocity, data for velocity-limiting factors, data concerning the distance to the velocity-limiting factor and driving resistance data.

The electronic control unit 100 is in signal communication with the means 150 for determining the maximum permissible lateral acceleration via a link 50. The electronic control unit 100 is arranged so as to receive, via the link 50, a signal from the means 1 50 representing lateral acceleration data for the maximum permissible lateral acceleration.

The electronic control unit 100 is in signal communication with the means 160 for prescribing velocity based on velocity-limiting factors occurring along the route of travel of the vehicle via a link 60a. The electronic control unit 100 is arranged so as to send, via the link 60a, a signal to the means 160 representing data for velocity-limiting factors such as curvature and/or changes in velocity limitation.

The electronic control unit 100 is in signal communication with the means 160 for prescribing velocity based on velocity-limiting factors occurring along the route of travel of the vehicle via a link 60b. The electronic control unit 100 is arranged so as to receive, via the link 60b, a signal from the means 160 representing velocity data for the prescribed velocity corresponding to a velocity profile and execution data for executing the velocity profile. The electronic control unit 100 is in signal communication with the means 162 for prescribing velocity based on the maximum permissible lateral acceleration of the vehicle and the curvature of the roadway along the route of travel of the vehicle via a link 62a. The electronic control unit 100 is arranged so as to send, via the link 62a, a signal to the means 1 62 representing lateral acceleration data for the maximum permissible lateral acceleration and curvature data for curvature along the route of travel of the vehicle.

The electronic control unit 100 is in signal communication with the means 162 for prescribing velocity based on the maximum permissible lateral acceleration of the vehicle and curvature via a link 62b. The electronic control unit 100 is arranged so as to receive, via the link 62b, a signal from the means 1 62 representing velocity data for the determined maximum vehicle velocity, taking into account curvature and the maximum permissible lateral acceleration. The electronic control unit 100 is in signal communication with the means 164 for prescribing velocity based on changes in velocity limitation along the route of travel of the vehicle via a link 64a. The electronic control unit 100 is arranged so as to send, via the link 64a, a signal to the means 164 representing acceleration data for the longitudinal acceleration required for upcoming changes in velocity limitation.

The electronic control unit 100 is in signal communication with the means 164 for prescribing velocity based on changes in velocity limitation along the route of travel of the vehicle via a link 64b. The electronic control unit 100 is arranged so as to receive, via the link 64b, a signal from the means 164 representing velocity data for the prescribed velocity corresponding to the change in velocity limitation.

The electronic control unit 100 is in signal communication with the means 170 for determining whether an initial required acceleration is negative or positive via a link 70. The electronic control unit 100 is arranged so as to receive, via the link 70, a signal from the means 170 representing acceleration data for negative/positive acceleration.

The electronic control unit 100 is arranged so as to process said data for velocity-limiting factors and data for the desired distance horizon plus velocity data and driving resistance data from the means 142 and so as to send said data to the means 140 for determining the acceleration required to achieve the prescribed velocity at an occurring velocity-limiting factor.

The means 140 for determining the acceleration required to achieve the prescribed velocity at an occurring velocity-limiting factor are arranged so as to process said data from the electronic control unit 100 in order to thus determine the required acceleration.

The means 160 for prescribing velocity based on velocity-limiting factors occurring along the route of travel of the vehicle are arranged so as to process said data for velocity-limiting factors such as curvature and/or changes in velocity limitation and lateral acceleration data for determining a velocity corresponding to a velocity profile, and so as to send velocity data for the prescribed velocity corresponding to a velocity and execution data for executing the velocity profile to the electronic control unit. Fig. 3a schematically illustrates a curvature profile R in the form of an S- curve with a first curvature having a radius of curvature r1 and a second curvature having a radius of curvature r2.

Fig. 3b schematically illustrates velocity profiles for the curvature profile in Fig. 3a determined by means of the system I according to the present invention. The velocity-limiting factor thus consists of a first and a second curvature.

The dotted line in Fig. 3b shows a reference velocity profile based on the determined acceleration required to achieve the prescribed velocity. The reference velocity profile thus shows the velocity request that is sent to the vehicle engine based on the required acceleration. Positive acceleration is thus requested between the first and second curvature to increase the velocity so that negative acceleration is requested in connection with the second curvature so as to retard the vehicle to a velocity adapted for the curve and corresponding to the permissible lateral acceleration. The broken line in Fig. 3b reflects the actual vehicle velocity. It thus consists of the executed velocity profile based on the determined required acceleration based on velocity-limiting factors in the form of the curvatures, taking into account the driving resistance, i.e. how the vehicle velocity is controlled based on the required acceleration. The vehicle is thus accelerated between the first and second curvature in order to increase the velocity so that it can be retarded in connection with the second curvature to a velocity adapted for the curve and corresponding to the permissible lateral acceleration. The solid line in Fig. 3b shows a velocity profile based on the maximum permissible lateral acceleration. The solid line thus shows a velocity profile based on the velocity-limiting factor.

Fig. 4 schematically illustrates a block diagram of a method for adapting the acceleration of a vehicle during driving of the vehicle along a route of travel according to one embodiment of the present invention.

According to one embodiment, the method for adapting the acceleration of a vehicle during driving of the vehicle along a route of travel comprises a step S1 . Occurrences of velocity-limiting factors along the route of travel of the vehicle are determined continuously in this step.

According to one embodiment, the method for adapting the acceleration of a vehicle during driving of the vehicle along a route of travel comprises a step S1 a. A velocity is prescribed in this step in connection with the determination of a velocity-limiting factor, based on the occurring velocity-limiting factor. According to one embodiment, the method for adapting the acceleration of a vehicle during driving of the vehicle along a route of travel comprises a second step S2. The acceleration required in connection with the determination of a velocity-limiting factor to achieve the prescribed velocity at an occurring velocity-limiting factor is determined in this step. The step of determining the acceleration required to achieve the prescribed velocity at the occurring velocity-limiting factor preferably comprises the step of continuously determining the driving resistance along the route of travel of the vehicle. The required acceleration is thus determined based on said determined driving resistance. The method preferably comprises the step of adapting the vehicle acceleration to correspond to the determined required acceleration. In this way, the prescribed velocity can be achieved at the position/time of the velocity-limiting factor. According to one embodiment, the step of determining the acceleration required to achieve the prescribed velocity at an occurring velocity-limiting factor occurs continuously.

According to one embodiment, said velocity-limiting factors include the curvature of the route of travel, whereupon the velocity is prescribed based on the maximum permissible lateral acceleration of the vehicle.

According to one embodiment, said velocity-limiting factors include changes in velocity limitation along the route of travel of the vehicle.

According to one embodiment, the step of continuously determining the driving resistance along the route of travel of the vehicle comprises the step of determining a mean value for the acceleration contribution that the driving resistance generates, whereupon the required acceleration is determined based on said mean value.

According to one embodiment, the step of continuously determining the occurrence of velocity-limiting factors along the route of travel of the vehicle occurs based on a predetermined distance- and/or time horizon ahead of the vehicle along the route of travel of the vehicle.

According to one embodiment, the step of prescribing velocity comprises prescribing velocity in the form of a velocity profile along the route of travel of the vehicle, and of continuously executing said velocity profile by continuously determining said required acceleration.

A diagram of an embodiment of a device 500 is shown with reference to Fig. 5. In one embodiment, the control unit 1 00 that is described with reference to Fig. 2 can comprise the device 500. The device 500 comprises a non-volatile memory 520, a data-processing unit 51 0 and a read/write memory 550.The non-volatile memory 520 has a first memory part 530 in which a computer program, such as an operating system, is stored for controlling the function of the device 500. The device 500 further comprises a bus controller, a serial communication port, I/O elements, 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 part 540.

A computer program P is provided that contains routines for adapting the acceleration of a vehicle during driving of the vehicle along a route of travel according to the innovative method. The program P contains routines for continuously determining the occurrence of velocity-limiting factors along the route of travel of the vehicle. The program P contains routines for prescribed velocity based on occurring velocity-limiting factors. The program P contains routines for determining, in connection with the determination of a velocity- limiting factor, the acceleration required to achieve the prescribed velocity in connection with the occurring velocity-limiting factor. The program P contains routines for continuously determining the driving resistance along the route of travel of the vehicle. The program P can be stored in executable fashion or in compressed fashion in a memory 560 and/or in a read/write memory 550.

When it is stated that the data-processing unit 510 performs a given function, it is to be understood that the data-processing unit 510 executes a certain part of the program that is stored in the memory 560, or a certain part of the program that is stored in the read/write memory 550. The data-processing device 510 can communicate with a data port 599 via a data bus 515. The non-volatile memory 520 is intended for communication with the data-processing unit 51 0 via a data bus 512. The separate memory 560 is intended to communicate with the data-processing unit 510 via a data bus 51 1 . The read/write memory 550 is arranged so as to communicate with the data-processing unit 510 via a data bus 514. For example, the links connected to the control unit 1 00 can be connected to the data port 599.

When data are received at the data port 599, they are stored temporarily in the second memory part 540. Once received input data have been temporarily stored, the data-processing unit 510 is arranged so as to carry out the execution of code in a manner as described above. The signals received at the data port 599 can be used by the device 500 to continuously determine the occurrence of velocity-limiting factors along the route of travel of the vehicle. The signals received at the data port 599 can be used by the device 500 to prescribe velocity based on occurring velocity-limiting factors. The signals received at the data port 599 can be used by the device 500 to determine, in connection with the determination of a velocity-limiting factor, the acceleration required to achieve the prescribed velocity at an occurring velocity-limiting factor. The signals received at the data port 599 can be used by the device 500 to continuously determine the driving resistance along the route of travel of the vehicle.

Parts of the methods described herein can be performed by the device 500 with the help of the data-processing unit 510 that runs the program stored in the memory 560 or the read/write memory 550. The method described herein is executed when the device 500 runs the program.

The foregoing description of the preferred embodiments of the present invention has been provided for illustrative and description purposes. It is not intended to be exhaustive, or to limit the invention to the described variants. Many modifications and variations will obviously be apparent to one skilled in the art. The embodiments have been chosen and described in order to best explain the invention and its practical applications, and to thereby enable one skilled in the art to understand the invention in its various embodiments and with the modifications that are appropriate for the intended use.

Claims

1 . A method for adapting the acceleration of a vehicle (1 ) during driving of the vehicle along a route of travel, comprising the steps of: continuously determining (S1 ) velocity-limiting factors occurring along the route of travel of the vehicle; and, in connection with the determination of a velocity-limiting factor, prescribing (S1 a) velocity based on occurring velocity-limiting factors and determining (S2) the acceleration required to achieve the prescribed velocity at the occurring velocity-limiting factor, characterized in that the step of determining the acceleration required to achieve the prescribed velocity at the occurring velocity-limiting factor comprises the step of continuously determining the driving resistance along the route of travel of the vehicle.

2. A method according to claim 1 , wherein the step of determining the acceleration required to achieve the prescribed velocity at an occurring velocity-limiting factor occurs continuously.

3. A method according to claim 1 or 2, wherein said velocity-limiting factors include the curvature of the route of travel, wherein the velocity is prescribed based on the maximum permissible lateral acceleration of the vehicle.

4. A method according to any of claims 1 -3, wherein said velocity-limiting factors include changes in velocity limitation along the route of travel of the vehicle.

5. A method according to any of claims 1 -4, wherein the step of continuously determining the driving resistance along the route of travel of the vehicle comprises the step of determining a mean value for the acceleration contribution that the driving resistance generates over a current distance horizon, wherein the required acceleration is determined based on the mean value.

6. A method according to any of claims 1 -5, wherein the step of continuously determining velocity-limiting factors occurring along the route of travel of the vehicle occurs based on a predetermined distance- and/or time horizon ahead of the vehicle along the route of travel of the vehicle.

7. A method according to any of claims 1 -6, wherein the step of prescribing velocity comprises prescribing velocity in the form of a velocity profile along the route of travel of the vehicle and continuously executing said velocity profile by continuously determining said required acceleration.

8. A system (I) for adapting the acceleration of a vehicle (1 ) during driving of the vehicle along a route of travel, comprising means (1 10) for continuously determining velocity-limiting factors occurring along the route of travel of the vehicle; means (160) for prescribing velocity based on velocity-limiting factors occurring along the route of travel of the vehicle, and means (140) for determining, in connection with the velocity-limiting factor, the acceleration required to achieve the prescribed velocity at the occurring velocity-limiting factor, characterized in that the means (140) for determining the acceleration required to achieve the prescribed velocity at the occurring velocity-limiting factor comprise means (142) for continuously determining the driving resistance along the route of travel of the vehicle.

9. A system according to claim 8, wherein the means (140) for determining the acceleration required to achieve the prescribed velocity at an occurring velocity-limiting factor are arranged for continuous determination.

10. A system according to claim 8 or 9, wherein said velocity-limiting factors include the curvature of the route of travel, wherein means (1 60) are present for prescribing velocity based on the maximum permissible lateral acceleration of the vehicle.

1 1 . A system according to any of claims 8-10, wherein said velocity-limiting factors include changes in velocity limitation along the route of travel of the vehicle.

12. A system according to any of claims 8-1 1 , wherein the means (142) for continuously determining the driving resistance along the route of travel of the vehicle comprise calculating means arranged so as to determine a mean value for the acceleration contribution that the driving resistance generates over a current distance horizon.

13. A system according to any of claims 8-12, wherein the means (1 10) for continuously determining velocity-limiting factors occurring along the route of travel of the vehicle comprise means for performing said determination based on a predetermined distance- and/or time horizon ahead of the vehicle along the route of travel of the vehicle.

14. A system according to any of claims 8-13, comprising means for prescribing velocity in the form of a velocity profile along the route of travel of the vehicle and means for continuously executing said velocity profile by continuously determining said required acceleration.

15. A vehicle containing a system (I) according to any of claims 8-14.

16. A computer program (P) for adapting the acceleration of a vehicle during driving of the vehicle along a route of travel, wherein said computer program (P) contains program code which, when it is run by an electronic control unit (1 00) or another computer (500) connected to the electronic control unit (1 00), enables the electronic control unit (100) to perform the steps according to claims 1 -7.

17. A computer program product comprising a digital storage medium that stores the computer program according to claim 16.