WO2006037360A1

WO2006037360A1 - Driver information system for information on the possibility of carrying out overtaking manoeuvres

Info

Publication number: WO2006037360A1
Application number: PCT/EP2004/011065
Authority: WO
Inventors: Kilian Funk; Dirk Ehmanns; Jan LÖWENAU
Original assignee: Bayerische Motoren Werke Aktiengesellschaft
Priority date: 2004-10-05
Filing date: 2004-10-05
Publication date: 2006-04-13

Abstract

The invention relates to a driver information system for information on the possibility of carrying out overtaking manoeuvres, comprising means for determination of the absolute vehicle position, means for determination of the road section lying before the motor vehicle in the direction of travel from said vehicle's position and means for determination of the properties of said section of road relevant to overtaking manoeuvres which further comprises means for the determination of further motor vehicle parameters relevant to overtaking manoeuvres relating to said motor vehicle and/or further motor vehicles and means for determination and output of a measure for the possibility of carrying out overtaking manoeuvres.

Description

Driver information system for information on the feasibility of overtaking

The present invention relates to a driver information system for informing the driver of a motor vehicle about the feasibility of overtaking operations comprising means for determining the absolute vehicle position, means for determining sections that lie from the vehicle's own position in the direction of travel in front of the motor vehicle, and means for determining for Overtaking relevant characteristics of the sections.

Modern motor vehicles are usually equipped with navigation systems, which are adapted to guide the driver by means of direction instructions on a calculated route from a current position to a destination. Next driver information systems are known by which the driver, depending on the current position, route and / or destination, further information is offered. This information may include publicly or individually for the respective vehicle offered service and entertainment offers, but also traffic information and detailed information on the characteristics of sections that the driver is expected or possibly driven.

From DE 102 55 331 A1, a driver information system is known, which is suitable for informing a driver about the properties of sections of a route that lie in front of the vehicle in the direction of travel from a vehicle location. A driver information system according to DE 102 55 331 A1 comprises means for determining the absolute vehicle position, means for determining sections of a route which lie in front of the vehicle from the vehicle position in the direction of travel and properties of the sections and means for output of the properties or Characteristics descriptive information to the driver. The characteristics of the route sections determined and displayed according to DE 102 55 331 A1 include properties of the route sections which are relevant for passing procedures. However, a driver information system according to DE 102 55 331 A1 has the disadvantage that the assessment of the low-risk feasibility of an overtaking process is still left to the driver of the motor vehicle. A driver information system according to DE 102 55 331 A1 only assists the driver in determining and outputting the boundary conditions of an eventual overtaking process given by the properties of the upcoming route sections. Due to the information offered restricted exclusively to the characteristics of the sections of the route to be traveled, it is not possible, by means of a driver information system according to DE 102 55 331 A1, to estimate the overtaking distance which is likely to be required for performing an overtaking operation. Reliable information about the actually available overtaking distance is also not possible on the basis of the available amount of information, since information regarding possibly oncoming vehicles is missing. The driver thus receives only incomplete information and no reliable indication of the feasibility of an overtaking process or of the risk incurred in the event of an overtaking process.

The present invention has for its object to provide a driver information system which is adapted to inform the driver of a motor vehicle reliably on the feasibility of overtaking.

The object is achieved by a driver information system which is suitable for determining and outputting a measure of the feasibility of overtaking processes, in the determination of which, in addition to route properties relevant to passing operations and the driver's own absolute vehicle position, relevant to overtaking operations related to his own vehicle and / or other motor vehicles Vehicle sizes are taken into account.

Only by additionally taking into account further motor vehicle sizes relevant for passing procedures is it possible to reliably estimate the feasibility of an overtaking operation. Among the other relevant for overtaking Motor vehicle sizes in this case primarily include quantities of movement of one's own motor vehicle, ie of the motor vehicle in which the driver information system is arranged. In addition to your own vehicle position, your own current speed and possibly your own current acceleration are of particular interest here. In addition, position and motion variables of other motor vehicles, in particular the current vehicle position, speed and possibly acceleration to overtaking vehicles are of paramount importance. Moreover, for a reliable estimate of the anticipated overtaking path, the acceleration capacity of the overtaking vehicle must be known. This acceleration usually depends, among other things, on the engine power, the weight of the vehicle and the current load and the current own speed.

Accordingly, a preferred embodiment of the invention comprises means for determining movement quantities of the own motor vehicle which exceed the absolute vehicle position.

Furthermore, particularly preferred embodiments of a driver information system according to the invention comprise means for determining the acceleration capacity of the overtaking motor vehicle and / or means for determining position and / or motion quantities of at least one further motor vehicle. Of particular interest here are position and / or movement quantities to be overtaken motor vehicles and position and / or motion quantities of oncoming motor vehicles. The determination of position and / or motion variables of other motor vehicles can in each case be absolute or refer to the own motor vehicle in which the driver information system is arranged.

In the event that a sufficient amount of overtaking relevant vehicle sizes is known in addition to properties relevant to passing sections in addition to overtaking relevant characteristics, the determination of the measure of the feasibility of overtaking by determining the length of the expected overtaking path, a determination of the length of the expected available overtaking and a comparison of Length of the expected overtaking path with the length of the expected overtaking available. The mathematical determination of the two mentioned lengths is feasible with the availability of the respective track characteristics and vehicle sizes with the aid of simple movement models with very little computational effort in the motor vehicle.

The actual determination of the relevant motor vehicle sizes for overtaking operations can be carried out in various ways, which are each isolated or used in any combination next to each other. The determination can be carried out on the basis of data which are obtained in a manner known per se by vehicle-vehicle communication or by intrinsic or environmental sensors of one or more of the participating motor vehicles. Additionally or alternatively, data for this purpose may also be received in a manner known per se by a data processing unit which is not located in one of the motor vehicles and which may be part of a satellite-supported positioning system, for example. In addition, certain relevant for overtaking vehicle sizes need not necessarily sensory detected or received, but can be factory preset and / or stored by an operator configurable in a memory unit and read from there.

According to a first development of the invention, a driver information system according to the invention also has means for displaying an operator action recommended for safely performing an overtaking operation. Conceivable here is in particular a haptic accelerator pedal, which makes the recommended for a sufficient vehicle acceleration accelerator pedal position for the driver felt.

The display of one or more such operator actions, as well as the underlying determination of the measure of the feasibility of an overtaking process and the display of this measure, can be done in the same way for all conceivable drivers or tuned to a typical driving behavior or preferences. According to a second development of the invention, a driver information system according to the invention therefore has means for determining the identity of the driver Determine driver, and the determination and / or output of the measure for the feasibility of overtaking and / or the display of a recommended operating action is carried out in dependence on parameters for the typical driving behavior of the driver and / or depending on a presettable by the driver.

It may also be useful to include external driving conditions in the determination or output of the measure of the feasibility of overtaking as well as in the display of a recommended operator action. Thus, a driver information system according to the invention according to a third embodiment of the invention comprises means for determining light and / or weather conditions and the determination and / or output of the measure for the feasibility of overtaking and / or the display of a recommended operating action in response to the light - and / or weather conditions.

The data processed in a driver information system according to the invention can also be advantageously used for further active improvement of driving safety by being transferred to an active driver assistance system. For such active driver assistance systems, methods are known to prevent high-risk or unworkable overtaking or safely complete ongoing high-risk overtaking. The risk can be estimated on availability of a driver information system according to the invention on the basis of data provided by this driver information system. A driver information system according to a fourth development of the invention is therefore suitable for outputting data, in particular warning signals for displaying risky or unworkable overtaking operations, to such an active driver assistance system.

Reference to the accompanying drawings, the invention will be further explained. This show schematically

1 is a block diagram of a driver information system according to the invention, FIG. 2 shows the driver's information representation of an optical output unit of the driver information system. FIG.

1 shows a block diagram of a particularly preferred embodiment of a driver information system according to the invention. The driver information system 1 can be implemented as a stand-alone system or as part of a vehicle navigation system. Alternatively, the driver information system 1 a

Vehicle navigation system include. The particularly preferred embodiment of a driver information system described below comprises a vehicle navigation system.

The driver information system 1 is arranged in a motor vehicle and comprises as essential components an information processing unit 2, means 3 for determining the absolute vehicle position, an input unit 4, an output unit 5, means 6 for the metrological determination of relevant motor vehicle sizes for overtaking, means 7 for communication with others Motor vehicles or data processing units and a memory unit 8. All components of the driver information system 1 can consist of one or more components. All components other than the information processing unit 2 may be embodied as separate components or as components integrated in the information processing unit 2. In the former case, a data connection between the respective component and the information processing unit 2 is provided.

The input unit 4 is used inter alia to enter a route, for example by entering start and end point of the individual sections of the route or the roads on a keyboard. If the driver information system according to the invention is connected to a vehicle navigation system, the input unit preferably serves to input a navigation destination. In this case, the information processing unit 2 calculates the traveling route to be traveled from the current vehicle position and the input destination. Under certain circumstances, data stored in the memory unit 8, eg map data, are taken into account. By the means 3 for determining the absolute vehicle position, here for example a locating device, the current absolute vehicle position can be determined. For this purpose, the locating device 3 preferably has a receiver for satellite signals of the Global Positioning System (GPS), which, with suitable evaluation in the receiver, permit a position determination that is accurate to a few meters.

In the memory unit 8 are data about sections and the Strecken¬ sections associated properties, in particular for overtaking relevant properties filed. These data may include overtaking prohibitions, the number of lanes, the width of lanes, unobstructed visibility, intersections, crests or slopes, inclines or inclines and / or bends (including curvature of the forward section), and the length over a particular property of the route sections , For example, speed restrictions or structural features such as bridges or tunnels. According to an alternative embodiment of the invention, the memory unit 8 can also be connectable to the driver information system 1 via a radio interface, in particular a mobile radio interface, for example according to the GSM or UMTS standard. For this purpose, the storage unit 8 can be held centrally approximately by a service provider and be selectable via the radio interface.

The output unit 5 is preferably embodied in the form of an optical display device, on which the sections of the route which lie in front of the vehicle on the traveled route in the direction of travel can be displayed, possibly in an abstracted representation and provided with additional information for the driver.

In addition, the output unit 5 according to an embodiment of the invention may include a haptic accelerator pedal or other means for displaying a recommended operating action.

The vehicle position is determined by the locating device 3. Furthermore, the driver information system 1 comprises means 6 for the metrological determination of further motor vehicle variables relevant for passing procedures and means 7 for Communication with other motor vehicles or data processing units. The means 6 for the metrological determination of further relevant for overtaking vehicle sizes include here various known per se sensors, which are essentially divided into intrinsic and environmental sensors.

By means of the self-sensors, data relating to the vehicle position of the motor vehicle variables of the own motor vehicle, such as the current speed and acceleration, are recorded. The recorded data are forwarded to the information processing unit 2 and evaluated there. The number of vehicle occupants or the current load weight can also be detected by self-sensors.

The environmental sensors in particular record data relating to motor vehicle sizes of other motor vehicles that are relevant for passing events. For example, by radar measurement and further data processing in the information processing unit 2, the current position, speed and / or acceleration of one or more other motor vehicles, in particular to be overtaken or oncoming vehicles can be determined in a conventional manner.

Alternatively or in addition to the metrological detection by intrinsic or environmental sensors, motor vehicle sizes relevant for overtaking processes, in particular with reference to other motor vehicles, can also be determined in a manner known per se by vehicle-vehicle communication. For this purpose, means 7 are provided for communication with other vehicles or data processing units, in the simplest case a transmitting and receiving unit for position data. Since the availability of suitable communication means 7, the possibility for communication with not arranged in vehicles data processing units may under certain circumstances for overtaking relevant motor vehicle sizes with respect to their own motor vehicle and / or other motor vehicles from a remote data processing unit, which for example part of a satellite positioning system with corresponding additional functions can be received. Furthermore, relevant motor vehicle sizes which, for example, influence the acceleration capability of the motor vehicle, can be stored in the memory unit 8 for overtaking operations. The storage of such data in the memory unit 8 can be done by the manufacturer or by inputs of the operator via the input unit 4. Motor vehicle sizes stored in the memory unit 8, in particular the engine power, can optionally be further processed in the information processing unit 2 together with sensory data, such as the current speed and / or the current load weight, in order to determine the effective acceleration capability of the motor vehicle.

A device according to the invention may have either a single or any combination of said means for metrological determination or for receiving or reading out motor vehicle variables relevant for passing operations.

If the required motor vehicle sizes relevant for overtaking operations are known, the following steps are carried out in the information processing unit 2 according to the embodiment of the invention described here. The length of an anticipated overtaking path is determined based on the relevant properties for passing sections and the motor vehicle variables relevant for passing procedures for various overtaking operations. The determination is made using physical motion models of the motor vehicles involved. As operating points, different time points or time sections or different route points or route sections can be selected. The calculation of the expected overtaking path is based on the assumption that an overtaking process is started at the respective operating point.

As an operating point, preference can be given to selecting all time or route points which mark the end of a time or route section in which overtaking is not possible (eg overtaking prohibition, Sichtverbauung, or passing by an oncoming vehicle). Alternatively, as operating points Zeit¬ or sections can be selected, with such a time or Start waypoint. By this procedure, which is based on the assumption that an overtaking always immediately after elimination of a

Obstruction is started, a maximum yield of overtaking opportunities can be obtained and displayed.

In order to be able to assess the continuation of ongoing overtaking processes, it may also be useful to always consider the current vehicle position as the operating point.

The calculation of the available overtaking path can be carried out in different ways. The known motor vehicle and road characteristics relevant for passing procedures can be taken into account in different detail. In the simplest case, it is assumed that all vehicles except the own motor vehicle continue to move at a constant speed. As an available passing lane can then be defined the path between the current vehicle position and the position at which the nearest oncoming motor vehicle in driving direction, when it has approached a vehicle to be overtook up to a car length, less a car length. (Theoretically, a shredding in front of the vehicle to be overtaken would still be possible if a car length remains between the overtaking vehicle and the oncoming motor vehicle.) If several motor vehicles are to be overtaken in an overtaking operation, the foremost vehicle to be overtaken is to be taken into account here.

The length of the overtaking path that is likely to be required can also be of varying complexity. In general, this is only one

Movement model needed to overhaul motor vehicles. For these, in the simplest case, it is also assumed that they continue to move at a constant speed. For the own motor vehicle is assumed in the simplest case, that it accelerates from the beginning of the overtaking process up to its end maximum. The length of the expected overtaking path is then, for example, the length of the path from the current vehicle position to the position at which the own motor vehicle is completely pulled past a motor vehicle to be overtaken. Are several motor vehicles in To overtake a passing process, here again the foremost to overtake motor vehicle to be considered.

To increase security, corresponding security surcharges can be defined or worst-case assumptions, in particular for the movement models of the others

Motor vehicles to be taken. As a security surcharge, for example, a distance over a car length serve route length, which is to be overtaken a motor vehicle even at the end of the overtaking still away from an oncoming motor vehicle. As a worst-case assumption, it can be assumed in the movement model, for example, that an overtaking and / or an oncoming motor vehicle also accelerates with a certain acceleration value.

The mathematical determination of the two mentioned lengths is feasible with the availability of the respective line properties and motor vehicle sizes with the aid of simple movement models with very little computational effort in the Informations¬ processing unit 2.

After each determination, the length of the likely overtaking path and the length of the likely to be available

Overtaking path compared. In the simplest case, the feasibility of an overtaking process is positively assessed if the length of the expected overtaking path is less than the length of the likely overtaking path. If this is not the case, the feasibility of the overtaking process is assessed negatively. The binary statement "positive" or "negative" in this case represents a measure of the feasibility of the overtaking process.

As an alternative to such a binary assessment, an upcoming overtaking operation may be assigned to one of several risk classes depending on the difference between the two particular lengths. For example, a first "high risk" risk class may include overtaking operations where the length of the expected overtaking path is only slightly less than the length of the likely overtaking path available the length of the expected overtaking path is significantly shorter than the length of the likely overtaking path. The grading of such risk classes is arbitrarily finely specified. In this case, the risk class determined for an upcoming overtaking event represents a measure of its feasibility.

The determination of the risk classes can be vehicle-dependent or driver-dependent. In the first case, it is left entirely to the respective driver, in particular for higher risk classes, to carry out a coordination between his subjective sense of risk and a risk class determined and displayed by the driver information system. In the second case, the preferences of the driver (for example, input via the input unit 4 and stored in the memory unit 8) and / or the driver's typical driving behavior (for example, taken from recorded driving data) are already taken into account when determining and / or displaying the risk classes. For an implementation of the second variant, the driver information system 1 must additionally comprise means not shown here for determining the identity of the driver. As a further variant, influencing the risk classes via one or more presets that can be influenced by the driver is conceivable.

Track properties can be taken into account in the calculation insofar as they affect movement models (speed limit causes acceleration only up to the maximum permitted vehicle speed), as absolute calculation variables enter into the calculation (non-visible curve limited available overtaking) and / or have superordinate effect (overlap A section of the route marked with a passing lane with the overtravel expected to be overturned will have a feasibility that is negative or the highest risk class). In the latter case, in order to save computational effort, it may be possible to prevent additional calculations from being made for a defined time or distance section.

As an alternative to the above-described concept of determining the length of the expected overtaking path and the length of the overtaking path which is likely to be available, the assessment of impending passing maneuvers may also be based on other way. For example, instead of the anticipated overtaking path, the overtaking time that is expected or required until completion of the overtaking operation can be taken into account. Instead of a classification into classes, a continuous assessment can be made. Alternative definitions and calculation methods for determining a measure of the feasibility of overtaking operations are therefore also within the scope of the invention.

If no determination of motor vehicle sizes of oncoming motor vehicles takes place, a determination of the expected overtaking distance is by definition excluded. Nevertheless, a measure of the feasibility of overtaking operations can be determined based on the other specific route characteristics and vehicle sizes. For example, the expected overtravel required in the manner already described can be calculated and related to an overtaking path, which consists of a on

Track properties limited visibility is available. Compared with the state of the art, there is still the decisive advantage here that the overtravel expected to be required is included in the calculation and thus the

Reliability of an issue to the driver can be increased.

With the aid of the output unit 5, the measure of the feasibility of overtaking operations determined in the information processing unit 2 in the manner described or in a comparable manner is output to the driver.

For this purpose, the driver is visualized according to a preferred embodiment of the invention for a variety of operating points related to the respective operating point risk class. As already described above, operating points in the exemplary embodiment described here each indicate the location of the start of an overtaking process. For visualization, for example, a lying in front of the driver in the direction of travel section can be shown schematically. The section includes a variety of operating points. The display of the route section is divided into several display elements. In the simplest case, each display element clearly corresponds to an operating point. The display of each display element is then according to the risk class of the respective Operating point influenced. This can be done by a color coding (eg red for "high risk", green for "low risk"), by different brightnesses and / or by different symbols. If the number of operating points and display elements is unequal, a corresponding interpolation or extrapolation can be carried out.

The indication of the risk classes may be independent of or combined with any indication of characteristics of the prior art links.

Fig. 2 shows the information of the driver serving on an optical output device of a driver information system according to the invention. The example shown shows an easily realizable monochrome graduation for representing the risk classes of the respective operating points. Bright display elements identify operating points, here track sections, with low risk class. Dark indicators indicate high risk class work items.

The exemplary representation in FIG. 2 includes the representation of six operating points, each of which represents a section of a length of 300 meters. The driver can take the information from the display that in the brightly marked operating points, a low-risk overtaking process can be started, while in the dark-marked operating points only with high risk overtaking can be started.

The gradation and / or representation of the operating points can also be non-linear, for example logarithmic, as an alternative to the linear division selected here. In particular, if, according to the preferred procedure already described, the operating points are selected such that they mark the end of a time or track section in which overtaking is not possible or only with high risk, contrary to the illustration in FIG. 2, there is no equidistant distribution Given operating points. Likewise, the distance range of the operating points used for the calculation and / or the distance range shown can be varied by entering the driver and / or depending on the currently available risk classes. By way of example, the distance range can be increased if a high risk class was consistently determined for operating points in the removal range previously used and / or illustrated for the calculation.

The provided in the example of FIG. 2 display of distance information can be done in a different manner compared to the example given, completely eliminated or executed in response to an input of the driver activatable.

According to a first development of the invention, the driver information system 1 is suitable for indicating to the driver an operating action recommended for the safe performance of an overtaking operation. For this purpose, the output unit 5 comprises means for displaying a recommended operating action, here a haptic accelerator pedal.

The haptic gas pedal makes the driver feel an accelerator pedal position, which the driver should obtain to safely complete an overtaking maneuver that has begun. Instead of the sole fact of a secure completion of the overtaking process, a gradation according to risk classes can also be usefully used here. For this purpose, vehicle-dependent or driver-dependent own risk classes related to this form of display can be defined or the risk classes used for determining and / or indicating the feasibility of overtaking operations can be used.

For example, using risk classes characterized by the difference between the required and available overtravers, for each risk class an accelerator pedal position to be maintained by the driver could be determined to make an overtaking maneuver likely to have a difference between the required and the required risk class standing overtaking path, ie with a safety distance corresponding to the risk class for reclosing after the overtaking procedure has been completed. According to the gradation can be made noticeable by the haptic accelerator, for example, several accelerator pedal positions, which in each case the

Possibility to mark a started overtaking process with a certain risk class. Different risk classes can be used in the same or different ways, for example, by different

Variation of accelerator pedal resistance, can be felt. Alternatively, the

Be aware of a single or a few selected risk classes that have been defined independently of driver, in particular on the preferences of the driver, tailored to risk classes.

According to another embodiment of the invention, external driving conditions are included in the determination or output of the measure of the feasibility of Überhol¬ operations and in the display of a recommended operating action. For this purpose, an inventive driver information system, for example, not shown here means for determining light and / or weather conditions. The determination and / or output of the measure for the feasibility of overtaking and / or the display of a recommended operating action then takes place as a function of the light and / or weather conditions. According to the procedure described up to here, for example, the limits of the risk classes are to be postponed depending on the light and / or weather conditions.

According to a further development of the invention, the data processed in a driver information system according to the invention are also used to actively improve driving safety. For this purpose, data are transmitted to an active driver assistance system via an in-vehicle data interface, not shown here, which is suitable for automatically preventing risky or unworkable overtaking processes or automatically completing ongoing high-risk overtaking operations. For example, the request for the intervention of the active driver assistance system can be given by the driver information system 1 according to the invention if the highest risk class is determined by the driver information system 1 for an ongoing passing process.

Claims

claims

1. Driver information system for informing the driver of a motor vehicle about the feasibility of overtaking operations having means for

Determining the absolute vehicle position, means for determining sections of track that lie in front of the motor vehicle in the direction of travel from the vehicle's own position, and means for determining properties of the sections that are relevant for passing procedures, characterized in that the driver information system further comprises means for

Determining further related to one's own and / or other motor vehicles relevant for overtaking vehicle sizes, and that the driver information system has means for determining and outputting a measure of the feasibility of overtaking.

2. driver information system according to claim 1, characterized in that the further related to the own and / or other motor vehicles for overtaking vehicle sizes relevant to the own motor vehicle related movement variables.

3. Driver information system according to one of claims 1 or 2, characterized in that the other related to the own and / or other motor vehicles relevant for overtaking Kraftfahrzeug¬ sizes include the acceleration capacity of the own motor vehicle.

4. Driver information system according to one of claims 1 to 3, characterized in that the further related to the own and / or other motor vehicles relevant for overtaking vehicle sizes include position and / or motion quantities of at least one other motor vehicle.

5. Driver information system according to claim 4, characterized in that the determination of the measure of the feasibility of overtaking by determining the length of the expected overtaking path, a Determining the length of the likely overtaking path available and comparing the length of the expected overtaking path with the length of the likely overtaking path.

6. Driver information system according to one of claims 4 or 5, characterized in that the driver information system is adapted to perform the determination of the position and / or movement quantities of the at least one further motor vehicle on the basis of data obtained by vehicle-vehicle communication or by Environment sensors are obtained or received by a not arranged in one of the motor vehicles data processing unit.

7. Driver information system according to one of claims 1 to 6, characterized in that the driver information system comprises means for displaying a recommended for a safe performance of an overtaking operation, in particular a haptic accelerator pedal.

8. Driver information system according to one of claims 1 to 7, characterized in that the driver information system comprises means which

Identify the identity of the driver, and that the determination and / or output of the measure for the feasibility of overtaking and / or the display of a recommended operating action in dependence on parameters for the typical driving behavior of the driver and / or a presettable by the driver presettable.

9. driver information system according to one of claims 1 to 8, characterized in that the driver information system comprises means for determining light and / or weather conditions, and that the determination and / or output of the measure of the feasibility of

Overtaking and / or the display of a recommended operating action depending on the light and / or weather conditions takes place.

10. Driver information system according to one of claims 1 to 9, characterized in that the driver information system is adapted to output data, in particular warning signals for displaying risky or not feasible overtaking, to an active driver assistance system.