VWGoA - Ex. 1004
`Volkswagen Group of America, Inc., Petitioner
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`MEASURE
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`CIALCUJYATE
`BIEHNCES
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`SEARCH FOR GAP
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`10
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`H
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`15
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`Fig. 7
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`o
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`17
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`GAP PRESENT?
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`n
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`STAY IN LANE
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`e
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`SIMULATION
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`LANE CHANGE
`POSSIBLE?
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`j
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`POSITIONING
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`2277653
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`1
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`Method for providing guiding assistance for a vehicle
`
`warm
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`The
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`invention relates to a method for providing
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`guiding assistance for a vehicle in changing lane from a
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`current lane to an adjacent target lane.
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`A method of this kind serves to support the driver
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`of the motor vehicle when changing lane, for example to feed
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`into or leave a motorway or to overtake a slower vehicle,
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`that
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`is to say to at
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`least partially relieve him of the
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`monitoring measures required for this and to assist him, by
`
`in the
`evaluating the data acquired during the monitoring,
`decision as to whether a risk-free lane change is possible.
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`Such
`
`a method
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`is
`
`disclosed
`
`for
`
`example
`
`in
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`DE 40 05 444 A1. In this publication,
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`the space behind the
`
`vehicle is monitored for the presence of objects, that is to
`
`say principally of vehicles travelling behind,
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`and the
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`distance from, and speed of, objects detected in this area
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`are determined. From this,
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`the deceleration which may have
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`to be performed by a vehicle travelling behind when the
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`driver’s own vehicle which is travelling in front changes
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`lane is calculated and an associated evaluation index is
`
`formed, the incremental values of which index are displayed
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`to the driver. As a result,
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`the latter receives audible or
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`visual
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`information on
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`a possible
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`lane
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`change graded
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`according to the expected adverse effect on the traffic
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`behind. A laser-impulse distance measuring device serves to
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`monitor the space behind.
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`Furthermore, in addition to ultrasonic and infrared
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`systems
`
`(see for example DE 38 32 720 A1,
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`in particular
`
`radar devices are known as monitoring detectors. The latter
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`are,
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`in addition to their use for monitoring the so—called
`
`blind-spot area
`
`(see for
`
`example DE 39 02 852 A1, used
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`principally for measuring distances from vehicles travelling
`
`ahead,
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`thus for example for driving with automatic distance
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`control
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`(see for example F. Ackermann, Distance Control
`
`Using Radar, Spektrum d. Wiss., June 1980, pp. 25 et seq. or
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`2
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`for acquiring overtaking recommendations such as in the case
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`of DE 36 22 447 C1,
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`in which nmnitoring of
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`the space in
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`front by radar is provided for this purpose.
`
`DE 36 22 091 A1 discloses
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`a
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`lane change warning
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`system in which a monitoring detector can be switched over
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`between monitoring of a blind-spot area and monitoring of a
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`space in front,
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`the monitoring of
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`the blind spot behind
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`being selected during a
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`lane
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`change warning mode of
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`operation and the monitoring of the space in front being
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`selected in a distance warning operation mode of coupled to
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`the switching of a fog lamp.
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`DE 30 28 077 C2 discloses a device for warning the
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`vehicle driver of a vehicle travelling ahead of him in the
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`current
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`lane,
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`in which. case the space in front
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`in the
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`current lane is monitored by means of a radar device for the
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`presence of a vehicle travelling ahead and the distance of
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`the driver’s own vehicle from a detected vehicle travelling
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`ahead and its relative speed is determined. As a function of
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`these parameters and the speed of the driver’s own vehicle
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`and, if appropriate, further parameters such as the state of
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`the carriageway and brakes, a safety distance between the
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`two vehicles is calculated which is then compared with the
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`measured distance. If the measured distance is smaller than
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`the safety distance, a warning signal is produced and/or the
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`risk of an impact is displayed on a visual display panel. In
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`a variant of
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`this known device,
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`there is additional
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`provision for the risk of a collision to be expected in the
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`event of changing lane to be indicated,
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`in that as well as
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`the space in front in the current lane, the respective space
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`behind on adjacent lanes is additionally monitored and the
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`detected data are evaluated in a manner analogous to that
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`for
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`the vehicle travelling ahead in the current
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`lane.
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`Consequently, for the evaluation of a possible lane change
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`this device only takes into account the respective current
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`situation in the space behind in a possible target lane.
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`The invention is based on the technical problem of
`
`providing a method for providing guiding assistance for a
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`3
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`motor vehicle when changing lane, which method is capable of
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`deciding automatically as
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`to the possibility of
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`an
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`instantaneous or future lane change and largely relieves the
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`driver of
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`the task of observing the surroundings
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`and
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`estimating distances and speeds.
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`According to the present invention there is provided
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`a method for providing guiding assistance for a motor
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`vehicle in changing lane from a current lane to an adjacent
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`target lane,
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`including the following steps:
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`a
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`both the space behind and the space in front in at
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`least the adjacent target
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`lane is monitored by means of
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`detectors for the presence of objects and the speeds of the
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`detected objects and of the driver’s own vehicle and the
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`distances of
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`the detected objects from the driver's own
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`vehicle are determined,
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`b
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`safety distances of the driver's own vehicle from
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`each of the detected objects are calculated as a function of
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`the speed data acquired in the previous step,
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`a reaction
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`time and given deceleration values are calculated,
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`c
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`the measured distances are compared with the calcu—
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`lated safety distances for each object and either
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`d.l
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`a possible
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`lane
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`change
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`is
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`signalled if
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`the
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`calculated safety distance for all the objects is greater
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`than, or at least the same size as,
`or
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`the measured distance,
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`d.2
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`a search for gaps is carried out if, for at least
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`one object
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`the measured distance is smaller
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`than the
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`in the following steps:
`calculated safety distance,
`d.2.1
`at least the sum of the measured distances of the
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`driver's own vehicle from the object in the space behind and
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`from the object in the space in front in the target lane is
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`compared with the corresponding sum of the calculated safety
`distances and
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`d.2.2
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`it is signalled that a lane change is not excluded
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`if at least one sum of the measured distances is greater
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`than the
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`corresponding sum of
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`the
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`calculated safety
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`distances and, otherwise, it is signalled that a lane change
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`is excluded.
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`By monitoring with detectors both the space behind
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`and the space in front in the target lane and by acquiring
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`the required distance and speed data of the objects detected
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`there,
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`above all vehicles,
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`this method is capable of
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`detecting whether a sufficient gap is present in the target
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`lane for a desired lane change, specifically taking into
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`account risk-preventing safety distances to be observed. The
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`driver does not need to keep an eye on the space behind nor
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`the space in front in the target lane nor does he need to
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`estimate the distances and speeds of the vehicles in it. He
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`is
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`informed by appropriate warning indications and/or
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`instructions from the computer-controlled guiding assistance
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`method of the presence of a sufficient gap in the target
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`lane in the case of a desired lane change. Here, the search
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`for a gap according to the invention permits it to be
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`detected whether, if possibly not
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`in the current vehicle
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`situation, a gap is at all in principle available in the
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`target
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`lane for a lane change. Thus, it is possible to
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`detect the presence of a gap, permitting a lane change,
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`in
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`the target lane obliquely in front of, or obliquely behind
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`the driver's own vehicle,
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`and to indicate this to the
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`driver. The said driver can then attempt by means of
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`suitable manoeuvres,
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`that
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`is
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`to say
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`in particular
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`acceleration or deceleration of his vehicle,
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`to position
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`himself level with this gap indicated to him by the guiding
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`assistance method and subsequently to carry out the lane
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`change. This
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`relieves the driver of
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`the vehicle in a
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`particularly advantageous manner of the tasks of observing
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`and evaluating the driving situation in the space in front
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`and behind in the target lane.
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`In a preferred embodiment,
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`in step a the space
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`behind and the space in front in the target lane is addi-
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`tionally monitored by means of detectors for the presence of
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`objects and the further steps are also carried out
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`in
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`relation to the objects detected there,
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`in which case,
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`in
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`order
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`to carry out
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`the search for gaps
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`in step d.2.1,
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`additionally
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`-
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`the sum of the measured distances from the object in
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`the space behind in the target lane and from the object in
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`the space in front in the current lane is compared with the
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`corresponding sum of the calculated safety distances and
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`-
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`the sum of the measured distances from the object in
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`the space behind in the current lane and from the object in
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`the space in front in the target lane is compared with the
`corresponding sum of the calculated safety distances, and in
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`step d.2.2
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`-
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`it is signalled that a lane change is not excluded
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`if in all three cases the sum of the measured distances is
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`greater than the corresponding sum of the calculated safety
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`distances and, otherwise, it is signalled that a lane change
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`is excluded., vehicles in the current lane, that is to say
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`the lane in which the driver’s own vehicle is located before
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`a lane change, are also included by the method as factors to
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`be considered. The
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`search for
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`a gap which is further
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`developed in this way does not only detect whether a gap is
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`in principle present
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`in the
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`target
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`lane
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`but
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`also
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`additionally whether the position in the current lane, that
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`is to say vehicles which may be located there in the space
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`in front or behind, permits such a gap to be reached by the
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`driver's own vehicle so that the driver is also relieved of
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`this task of evaluating the driving situation in the current
`lane.
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`Advantageously,
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`the question as
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`to whether
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`a
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`detected gap, which is in principle sufficient for a lane
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`change,
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`in the target lane can in practice even be reached
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`by the driver manoeuvring his car can also be answered by
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`the guiding assistance method in that the possible future_
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`driving behaviour for reaching the gap is played through in
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`a computer simulation and tested as to whether the gap is
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`actually reachable.
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`In a further development of this idea,
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`the necessary acceleration or deceleration values, which are
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`detected by the simulation in the case of a reachable lane
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`change, for the driver's own vehicle are either displayed to
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`6
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`the driver or, together with a further increase in driving
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`comfort, passed on directly to a
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`longitudinal movement
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`controller device, which
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`is possibly present,
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`of
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`the
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`vehicle, which
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`device
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`is
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`capable
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`of
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`automatically
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`controlling the movement of the vehicle in the direction of
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`travel without the intervention of the driver.
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`A particularly high level of driving comfort with
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`respect to the control of the vehicle can be achieved with
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`a
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`further
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`embodiment of
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`the invention in which it is
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`signalled to a transverse movement controller device, which
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`may be present, of the vehicle that a gap which permits a
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`lane change has been reached and the said transverse
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`movement controller device automatically causes the vehicle
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`to move out in the target lane and to be fed into the gap in
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`the target
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`lane without
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`the driver having to perform
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`steering movements
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`himself.
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`In
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`conjunction with
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`a
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`longitudinal movement controller device which is actuated
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`simultaneously, a method for completely autonomous vehicle
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`control including possible lane changes is realized without
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`controlling interventions of the driver being required.
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`An advantageous
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`embodiment of
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`the invention is
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`illustrated in the drawings and described below by way of
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`example. In the said drawings:
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`Fig. 1
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`shows
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`a programme
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`sequence plan of a computer-
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`controlled guiding' assistance method for
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`a
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`lane
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`change,
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`Figs. 2 to 6 show different vehicle situations in order to
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`illustrate the guiding assistance method and
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`Fig. 7
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`shows a diagrammatic illustration of the monitored
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`areas used by the method.
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`In the illustrations of carriageways in Figs. 2 to
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`7,
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`in each case a vehicle 0 is shown in a current
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`lane 8
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`with a vehicle 2 travelling ahead in this current lane 8 and
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`a vehicle 4
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`following, and in a target
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`lane 9 a front
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`vehicle 3 and a rear vehicle 1 are shown,
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`the direction of
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`travel being indicated in each case by the arrow 25. In Fig.
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`2,
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`the respective distances 501, $02, $03,
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`504 of
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`the
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`10
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`7
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`driver’s own vehicle 0 from the four other vehicles 1, 2, 3,
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`4 are entered.
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`It
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`is clear
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`from Fig.
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`7
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`that
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`the driver's own
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`vehicle 0 has a rearumounted radar device HR for monitoring
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`the space 23 behind in the current lane 8, a distance radar
`device AR for’ monitoring'
`the space 24
`in front
`in.
`the
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`current lane 8, a blind-spot radar device TWR for monitoring
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`the space 21 behind in the adjacent target
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`lane 9 and a
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`forward—directed radar device VR for monitoring the space 22
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`in front in the target lane 9. These detector devices detect
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`the presence of objects in the area respectively covered by
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`to be
`the distance from the object
`them and also permit
`determined. The term object here includes other vehicles and
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`stationary obstacles which may be encountered, for example
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`at the end of a lane. The blind—spot radar and the forward-
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`directed radar TWR, VR are integrated in the exterior
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`mirrors. The angle of the radar lobe is sufficiently large
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`to reduce the blind spot. The monitoring of the space behind
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`requires
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`a
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`range
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`of
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`the
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`blind— spot
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`radar
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`in the
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`longitudinal direction of at least approximately 100 m.
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`The mode of operation of the method for computer-
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`assisted guiding assistance for a driver's motor vehicle 0
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`when changing lane from the current lane 8 to the adjacent
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`target
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`lane 9, which in the case shown constitutes an
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`overtaking lane located to the left of the current lane 8 in
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`the direction of travel,
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`is explained in detail below with
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`reference to the programme sequence plan of Fig. 1.
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`The method is initiated by means of an activation
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`step 10 which is formed by a travel direction indicator
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`lever being activated.
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`The
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`system is
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`thus activated
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`simultaneously with the triggering of the travel direction
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`indicator. As an alternative there may be provision for the
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`method
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`to be activated by
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`simply tapping the travel
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`direction indicator
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`lever without
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`the travel direction
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`indication being triggered so that the other road users are
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`not confused by the intention of a possibly momentary but
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`not yet
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`realizable lane
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`change.
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`The
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`travel direction
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`8
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`indication is not
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`issued until a gap is detected for a
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`possible lane change
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`and the driver's own vehicle has
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`reached the position required for the lane change. This
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`actuation is preferably cancelled if it has not been
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`possible to find a gap within a predetermined time, after
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`which the driver
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`is requested to repeat it if he still
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`intends to change lane. If, on the other hand,
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`the other
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`road users are informed of the imminent intention of a lane
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`change by the immediate lighting up of the travel direction
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`indicator,
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`the other
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`road users may react differently,
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`either by leaving space for a sufficient gap or else by
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`closing a gap which may be present and thus making a lane
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`change impossible.
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`A further alternative consists
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`in the vehicle-
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`mounted system, which carries out the method, remaining con-
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`tinuously activated and only the data output
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`to corres-
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`ponding display devices or vehicle movement-controlling
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`devices is actuated in each case by the request for an
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`indication of
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`a
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`change
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`in travel direction.
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`In this
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`procedure, the computer and the data lines are continuously
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`occupied and ready. If, on the other hand, the system which
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`carried out
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`the method is only activated in each case in
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`response to the request for a travel direction indication,
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`as
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`a result it can be used in the meantime for other
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`purposes also. It is to be noted at this point that the
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`method can be carried out by means of a customary vehicle-
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`mounted computer system, such as is known for example for
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`the purpose of automatic distance—controlled driving,
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`for
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`which reason a detailed description of the system components
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`is dispensed with here.
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`The
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`request
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`for
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`the activation of
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`the travel
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`direction indicator can be communicated to the driver, if
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`desired, by the forward-directed monitoring in the current
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`lane 8 if it is detected during this process that there is
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`an object 2 in this area 24 in front which is moving more
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`slowly in the direction of
`vehicle 0.
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`travel
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`than the driver's own
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`9
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`After activation,
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`in a
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`following step 11
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`the
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`distances $01, 502, 503 and 504 from the objects 1 to 4
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`which are detected in the monitored areas 21 to 24 and their
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`relative speeds with respect to the driver’s own vehicle 0
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`are measured from the driver’s own vehicle by means of the
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`radar devices and the driver’s own speed v0 is determined by
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`means of the speedometer.
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`In order to retain the data of
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`these variables,
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`the raw data of
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`the radar devices are
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`preprocessed here according to their purpose,
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`faults for
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`example due to signal
`
`reflections are filtered out and
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`sufficient plausibility tests are carried out. For example,
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`the objects 1 to 4 detected when cornering are assigned to
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`the respective lane by means of the steering angle. If the
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`relative speed of an object is equal and opposite to the
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`speed
`
`of
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`the driver’s
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`own vehicle,
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`this object
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`is
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`interpreted as a stationary obstacle or the end of a lane,
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`for example a feeding-in lane.
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`If contradictory signals
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`occur which cannot be evaluated,
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`this is indicated to the
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`driver if he has actuated the travel direction indicator.
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`Vehicles travelling in the opposite direction on an oncoming
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`carriageway can be blanked out or a warning signal can be
`
`triggered when the travel direction indicator is actuated.
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`the safety distances sw01,
`In a following step 12,
`stZ, st3 and st4 are calculated from the distance and
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`speed data acquired in the previous step. For this purpose,
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`initially the absolute speeds v1, v2, v3 and v4 of the other
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`vehicles and detected objects 1 to 4 are calculated from the
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`relative
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`speeds
`
`and
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`the
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`vehicle's
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`own
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`speed
`
`v0.
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`Subsequently,
`
`the safety distances are formed in each case
`
`as a sum from a reaction distance, a residual distance, a
`
`braking distance differential and a distance for coasting to
`
`a standstill.
`
`The reaction distance is obtained from the product
`
`of a reaction time and the speed of the respective vehicle
`
`behind. A customary driver’s reaction time,
`
`for example
`
`1.8 s, can be set for the reaction time. When starting a
`
`distance control,
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`the shortest system reaction time can be
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`13
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`13
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`

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`10
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`used at this point. The residual distance forms a safety
`
`margin and is typically set at approximately 5 m. Braking
`distance differential
`is understood to be the difference
`
`between the braking distances for full braking of the two
`
`vehicles between which the safety distance has just been
`
`for example typically
`the maximum deceleration,
`detected,
`3 m/szbeing specified or, if the driver’s own vehicle 0 has
`
`appropriate devices, being determined automatically by means
`
`of the coefficient of friction dependent on the state of the
`
`road. Finally, the distance for coasting to a standstill is
`
`obtained from non—driven rolling of
`
`the vehicles with a
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`reasonable deceleration which is typically 1 m/sz. with
`
`these specified parameters of which,
`
`incidentally,
`
`the
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`residual distance and the reaction time can be matched by
`
`means of an adaptive control,
`
`the computer of the system
`
`calculates the safety distances stl to st4 of the driver's
`
`own vehicle 0 from each of the detected objects or vehicles
`
`1 to 4.
`
`In a following step 13 an interrogation takes place
`
`as to whether the safety distances have all been maintained,
`
`in that the measured distances s01 to 504 are compared with
`
`the calculated safety distances stl to sw04.
`
`If
`
`the
`
`driver's own vehicle 0 has a distance controller device, for
`
`example in conjunction with a speed control,
`
`the safety
`
`distance sw02 from the vehicle 2 travelling ahead in the
`
`current
`
`lane 8 is automatically maintained and it is only
`
`necessary to check the other distances.
`
`If the computer
`
`determines that all the measured distances are greater than
`
`or at least the same size as the respectively associated
`
`calculated safety distances, it signals that a lane change
`
`can be realized in the current situation and indicates this
`
`to the driver appropriately. He can then carry out the lane
`
`change in a following step 14, after which the system
`
`returns again to the point A before the actuation of the
`
`system.
`
`When carrying out
`
`this method step it may be
`
`advantageous not to use precisely calculated limits of the
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`14
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`14
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`

`11
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`Safety distance but rather,
`
`in particular during a lane
`
`change,
`
`to execute the distance boundaries according to a
`
`plausibility test somewhat
`
`imprecisely or to provide them
`
`with hysteresis properties. Furthermore,
`
`the inclusion of
`
`acceleration processes, which have already been started, of
`
`individual vehicles
`
`in the calculation of
`
`the safety
`
`distances can be useful to the flow of traffic.
`
`If, on the other hand,
`
`the computer has calculated
`
`that one of
`
`the measured distances is smaller
`
`than the
`
`associated safety distance, this means that a current lane
`
`change is not possible. The method programme then provides
`
`a search for a gap as the next step 15. During this, it is
`
`determined whether a gap which is sufficient for a lane
`
`change, if it is not already at the level of the current
`
`position of the driver’s own vehicle 0 is possibly located
`
`obliquely in front of or obliquely" behind the driver’s
`
`vehicle 0 and is basically also accessible to the driver’s
`
`vehicle
`
`0.
`
`For
`
`this purpose,
`
`the
`
`following measured
`
`distances and calculated safety distances are summed and
`
`compared by the computer. Firstly, the sum $01 + 503 of the
`
`measured distances from the vehicles 1, 3 in the target lane
`
`9 and the sum sw01 + sw03 of
`
`the associated calculated
`
`safety distances. The
`
`computer
`
`compares both sums
`
`and
`
`detects the presence of a gap in the target lane 9 if the
`
`sum of the measured distances is greater than the sum of the
`
`calculated safety distances. Secondly, it calculates the sum
`
`501 + $02 of the measured distances between the vehicle 1
`
`behind in the target
`
`lane 9 and the vehicle 2 which is
`
`travelling ahead in the current lane 8 and likewise in turn
`
`calculates the associated sum stl + stZ of the calculated
`
`safety distances. The same is carried out as a third step
`
`with the distances of the two other vehicles 3, 4. Both sums
`
`$01 + 502, 503 + 504 of the measured distances are then in
`
`turn compared in each case with the associated sum of the
`
`calculated safety distances and if it is detected in both
`
`cases that the sum of the measured distances is greater than
`
`the sum of the associated calculated safety distances, this
`
`15
`
`15
`
`

`

`12
`
`is interpreted.
`
`to mean.
`
`that
`
`space is available for the
`
`driver’s own vehicle 0 to accelerate or decelerate, as a
`
`result of which it may be possible to reach the detected gap
`
`in order to change lane.
`
`If,
`
`subsequently,
`
`in at
`
`least one of
`
`the three
`
`comparisons of this interrogation step 16,
`
`the sum of the
`
`measured distances is smaller than the sum of the calculated
`
`safety distances, this is interpreted to mean that under the
`
`set parameters, such as for example reaction time, safety
`
`margin,
`
`residual distance,
`
`the driver’s acceleration or
`
`deceleration and
`
`reasonable deceleration of
`
`the other
`
`vehicles, a lane change is not possible. In consequence,
`
`in
`
`a following step 17,
`
`the instruction to stay in lane is
`
`issued to the driver.
`
`In the method sequence,
`
`the system
`
`then returns to point B before the measurement step 11 and
`
`from there a new run-through the method begins, during which
`
`new measurement data, which may arise from possible changes
`
`in the positions or speeds of the vehicles, are acquired.
`
`If, on the other hand, in all three comparisons the
`
`sum of the measured distances is greater than that of the
`
`calculated safety distances,
`
`this is interpreted to mean
`
`that firstly a gap is available for a lane change and
`
`secondly this gap can also be reached, not immediately but
`
`after suitable vehicle manoeuvres have been carried out, in
`
`particular an acceleration or deceleration process. This can
`
`be signalled to the driver by the system, for example by
`means of an LED.
`
`The method provides extensive assistance to the
`
`driver in dealing with the problem which then occurs as to
`
`how he can reach by means of suitable manoeuvres with his
`
`own vehicle 0 the gap which is basically present
`
`in the
`
`target
`
`lane 9,
`
`in which case changes
`
`in the driving
`
`behaviour of
`
`the other vehicles
`
`1
`
`to 4,
`
`for
`
`example
`
`accelerations, decelerations or lane changes, are currently
`
`taken into account. For this purpose, subsequently, there is
`
`provision for a simulation step 18 after a positive response
`
`in the preceding interrogation step 16 which enquired
`
`16
`
`16
`
`

`

`13
`
`whether a gap was basically present.
`
`In this process,
`
`the
`
`future procedure until the gap is reached is played through
`
`in a computer simulation with all the vehicles 0, 1, 2, 3,
`
`4 because it is a highly non-linear problem, since a change
`
`in the vehicle's own speed means at the same time a change
`
`in the calculated safety distances. Even when the speed of
`
`the other vehicles is constant,
`
`such an increase in the
`
`vehicle’s own speed v0 can occur that when the gap remains
`
`the same
`
`size the safety distances
`
`from the vehicles
`
`travelling ahead may no longer be maintained or that the
`
`specified acceleration is not sufficient to carry out the
`
`change in position within a period in which the change in
`
`traffic situation permits a lane change. In both cases, an
`
`initiated overtaking process would have to be aborted, for
`which reason the simulation which is calculated in advance
`
`in the time accelerator is appropriate at this point. The
`
`radar devices according to Fig. 7 detect here the currently
`
`occurring traffic situation with the distances and speeds of
`
`the other vehicles. On the basis of this situation, it is
`
`played through in the simulation whether, and by means of
`
`which activities, it may become possible for the driver to
`
`feed into the gap which has been found.
`
`For this simulation, a negative acceleration value,
`
`that
`
`is to say a deceleration,
`
`is prescribed if the
`
`calculated safety distances from the vehicles 1, 4 behind
`
`are both maintained.
`
`If, on the other hand,
`
`the safety
`
`distances from the two front vehicles 2, 3 are maintained by
`
`the measured distances, a positive acceleration value, that
`
`is to say an actual acceleration, is prescribed. Thus,
`
`the
`
`traffic behaviour is simulated in advance, specifically in
`
`the longest case until, when accelerating, the distance from
`
`the vehicle 2 travelling ahead in the current lane 8 or,
`
`when decelerating, the distance from the vehicle 4 following
`
`in the current lane 8 drops below the respective associated
`
`safety distance. If the existing gap is not reached by this
`
`time, when accelerating' a new simulation cycle with an
`
`incrementally increased acceleration value is carried out.
`
`17
`
`17
`
`

`

`14
`
`The interrogation step 19 as to a possible lane change, on
`
`accelerating, is not ultimately answered negatively, and the
`
`driver in turn given the instruction in step 17 to stay in
`
`lane, until it has not been possible to reach the gap after
`
`a set upper limit for the acceleration value, which results
`
`for example from the smallest value of the engine output
`
`threshold,
`
`the threshold of the coefficient of friction or
`
`an individual comfort threshold, has been reached or after
`
`a prescribed maximum speed has been reached. 0n the other
`
`hand, for reasons of driving comfort the deceleration in the
`
`simulation is not increased incrementally but set right at
`
`the beginning to a value which is still advantageous for
`
`comfort.
`
`If
`
`the gap is not
`
`reached after
`
`the single
`
`deceleration simulation cycle,
`
`the instruction to stay in
`
`lane is issued to the driver again.
`
`If, on the other hand, during the simulation, it is
`
`detected in the interrogation step 19 that a lane change is
`
`possible by means of the simulated vehicle manoeuvre,
`
`the
`
`data detected for this, relating to the vehicle acceleration
`
`or deceleration, are output. These data are output on the
`
`one hand to a display device for
`
`the driver, who can
`
`subsequently set the required acceleration or deceleration
`
`value and then perform the manoeuvre to reach the gap in the
`
`target lane under his own control. This realization of the
`
`previously simulated vehicle manoeuvre is described with
`
`step 20 of the positioning in the programme sequence plan in
`
`Fig.
`
`1.
`
`If
`
`the vehicle has
`
`a
`
`longitudinal movement
`
`controller device for automatic movement of the vehicle in
`
`the longitudinal direction,
`
`the data can be output, on the
`
`other hand,
`
`to this longitudinal movement controller which
`
`then automatically moves the vehicle onto the acceleration
`
`or deceleration value detected in the simulation. After the
`
`transfer of data, the system returns to point B before the
`
`measurement step 11 from where the method is run through
`again in order finally to detect that the sufficient gap has
`
`been reached and to be able to perform the desired lane
`
`change.
`
`18
`
`18
`
`

`

`15
`
`A completely autonomous vehicle control
`
`including
`
`lane changes without any intervention of the driver being
`
`necessary is possible if the vehicle additionally has
`
`a
`
`transverse movement controller' device. Then, when it is
`
`detected that
`
`a
`
`lane
`
`change
`
`is possible,
`
`this
`
`same
`
`possibility is
`
`signalled to the
`
`transverse movement
`
`controller after which the lane change
`
`is carried out
`
`automatically by the longitudinal movement controller and
`
`transverse movement controller of
`
`the vehicle, possibly
`
`after an appropriate request from the driver.
`
`The method is explained below applied to different
`
`traffic situations according to Figs. 2 to 6.
`
`Fig. 2 shows an example in which it is presumed that
`
`all the safety distances are maintained. The execution of
`
`the method described above
`
`results in the gap in the
`
`adjacent, here left-hand target
`
`lane 9,
`
`and thus
`
`the
`
`possibility of an immediate lane change, are detected.
`
`In the case in Fig. 3, the safety distance from the
`
`vehicle 1 behind in the target lane 9 is not maintained and
`
`the system which carries out the method thus detects that an
`
`instantaneous lane change is not possible. However,
`
`the gap
`
`search step 15 leads to a positive response to the question
`
`of a gap being basically present which is located obliquely
`
`in front of
`
`the driver's own vehicle 0. The measured
`
`distance from the vehicle 2 travelling ahead in the current
`
`lane 8 gives rise to a free distance for acceleration.
`
`In
`
`the subsequent simulation, it is played through whether, and
`
`if so with what acceleration, it is possible to position the
`
`vehicle in this gap at a safe distance from all the other
`vehicles.
`
`In the traffic situation according to Fig. 4,
`
`the
`
`safety distance from the vehicle 3 travelling ahead in the
`
`target lane 9 is not maintained. The system which carries
`
`out the method detects in turn that an immediate lane change
`
`is not possible. The subsequent search for a gap gives rise
`
`to a positive response to the question of a gap being
`
`basically present which in this case is located obliquely
`
`19
`
`19
`
`

`

`16
`
`behind the driver's own vehicle 0. The measured distance
`
`from the vehicle 4 travelling behind in the current lane 8
`
`turns out to be considerably greater than the calculated
`
`safety distance, which indicates
`
`a
`
`free distance for
`
`deceleration.
`
`In the subsequent simulation, it is played
`
`through whether it is possible to position the vehicle in
`
`the gap at a safe distance from the other vehicles by means
`
`of the preselected deceleration or by simply waiting.
`
`In the case in Fig. 5, as in the case in Fig. 3, the
`
`presence of a gap.is in turn detected obliquely in front of
`
`the driver's own vehicle 0. The distance from the vehicle 2
`
`travelling ahead in the current lane 8 corresponds, however,
`
`approximately to the calculated safety distance, for which
`
`reason there is no distance free for acceleration so that
`
`the question of a possible lane change in step 19 has to be
`
`answered negatively' and the instruction to