Driving assistance device

A driving assistance device including: a preceding vehicle detection portion; a speed control portion controlling the speed adjustment to the host vehicle to obtain a target inter-vehicle distance; a preceding vehicle travel trajectory acquisition portion; an entering vehicle detection portion; an entering vehicle travel trajectory acquisition portion; a target trajectory setting portion setting the target travel trajectory of the host vehicle based on at least the travel trajectory of the preceding or the entering vehicle; a steer control portion controlling the adjustment of the steer amount calculated based on the target travel trajectory; and a location determination portion determining the location where the deviation amount between the travel trajectories of the entering and preceding vehicles becomes the predetermined value or below. The target trajectory setting portion sets the target travel trajectory of the host vehicle based on the travel trajectory of the entering vehicle, after the determined location.

INCORPORATION BY REFERENCE

The disclosure of Japanese Patent Application No. 2013-196057 filed on Sep. 20, 2013 including the specification, drawings and abstract is incorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present disclosure relates to a driving assistance device that assist a vehicle in driving.

2. Description of Related Art

A driving assistance device is known as a device used to assist in keeping a safe inter-vehicle distance between a host vehicle as an assistance object and a preceding vehicle travelling in the travel direction of the host vehicle. When performing driving assistance, such a device can detect a relative position and a relative speed of an object in front of the vehicle's travel direction, thereby identifying the presence of a preceding vehicle. Moreover, the device performs an inter-vehicle control (speed control), to make the host vehicle follows the identified preceding vehicle. For example, Japanese Patent Application Publication No. 2007-176290 (JP 2007-176290 A) discloses an example relating to such a driving assistance device.

The driving assistance device disclosed in JP 2007-176290 A includes: host vehicle driving information detection means for detecting the host vehicle's travelling information; preceding vehicle information detection means for detecting the preceding vehicle information as travelling information of a preceding vehicle relative to the host vehicle. Also, the device includes steering control amount calculation means for calculating a control target value according to the positions of the preceding vehicle and the host vehicle, and calculates a steering control amount for following the preceding vehicle with a feedback control which is based on the control target value. Moreover, the driving assistance device also includes control gain setting means for temporarily decreasing the control gain of the feedback control when the preceding vehicle detection means detects that the preceding vehicle is switched. By such a configuration, an assistance to control an inter-vehicle distance between the host vehicle and the preceding vehicle is performed.

According to the driving assistance device disclosed in JP 2007-176290 A, when a vehicle enters between the host vehicle and the preceding vehicle, the control gain of the feedback control is decreased, thus, a sudden performing of a strong driving assistance caused by the entering vehicle mostly detected in a position near the host vehicle is restrained. Besides, by restraining the rapid change during the driving assistance, the uncomfortable feeling of the users brought by the assistance will be restrained.

Incidentally, the preceding vehicle switching detection of the driving assistance device etc. disclosed in JP 2007-176290 A is mostly performed by prioritizing maintaining a safe inter-vehicle distance; when the preceding vehicle is switched, sometimes, large deviation will remain between a travel trajectory of the preceding vehicle before switching and a travel trajectory of the preceding vehicle after switching in a width direction of the host vehicle. Therefore, due to the switching of the preceding vehicle, even if the control gain decreases, it is concerned that the driving position of the host vehicle greatly moves (unsteadiness) in the width direction of the host vehicle from the travel trajectory of the preceding vehicle before the detected switching to the travel trajectory of the preceding vehicle after switching.

SUMMARY OF THE INVENTION

The invention provides a driving assistance device, which restrains the moving (unsteadiness) of a host vehicle in a width direction even if an entering vehicle enters between the host vehicle and a preceding vehicle.

A first aspect of the invention is a driving assistance device that includes: a preceding vehicle detection portion that detects a preceding vehicle in front of a host vehicle in which the driving assistance device is disposed; a speed control portion that controls a speed adjustment of the host vehicle to make an inter-vehicle distance between the host vehicle and the preceding vehicle become a target inter-vehicle distance; a preceding vehicle travel trajectory acquisition portion that acquires a travel trajectory of the preceding vehicle; an entering vehicle detection portion that detects an entering vehicle which enters between the host vehicle and the preceding vehicle; an entering vehicle travel trajectory acquisition portion that acquires a travel trajectory of the entering vehicle detected by the entering vehicle detection portion; a target trajectory setting portion that sets a target travel trajectory of the host vehicle based on at least one of the travel trajectory of the preceding vehicle and the travel trajectory of the entering vehicle; a steering control portion that controls an adjustment of a steer amount of the host vehicle based on the target travel trajectory; and a location determination portion that determines a location where a deviation amount between the travel trajectory of the entering vehicle and the travel trajectory of the preceding vehicle becomes a predetermined value or below. The speed control portion sets the entering vehicle as the preceding vehicle of the speed control portion when the entering vehicle is detected by the entering vehicle detection portion, and the target trajectory setting portion sets the target travel trajectory of the host vehicle based on the travel trajectory of the preceding vehicle before entering of the entering vehicle at least until reaching the location determined by the location determination portion after the speed control portion sets the entering vehicle as the preceding vehicle, and sets the target travel trajectory of the host vehicle based on the travel trajectory of the entering vehicle after the location determined by the location determination portion.

A second aspect of the invention is a driving assistance device that includes: a preceding vehicle detection portion that detects a preceding vehicle in front of a host vehicle in which the driving assistance device is disposed; a speed control portion that controls a speed adjustment of the host vehicle to make an inter-vehicle distance between the host vehicle and the preceding vehicle becomes a target inter-vehicle distance; a preceding vehicle travel trajectory acquisition portion that acquires a travel trajectory of the preceding vehicle; an entering vehicle detection portion that detects an entering vehicle which enters between the host vehicle and the preceding vehicle; an entering vehicle travel trajectory acquisition portion that acquires a travel trajectory of the entering vehicle detected by the entering vehicle detection portion; a target trajectory setting portion that sets a target travel trajectory of the host vehicle based on at least one of the travel trajectory of the preceding vehicle and the travel trajectory of the entering vehicle; a steering control portion that controls an adjustment of a steer amount of the host vehicle based on the target travel trajectory; and a location determination portion, that determines a location where a deviation amount between the travel trajectory of the entering vehicle and the travel trajectory of the preceding vehicle becomes a predetermined value or below. The speed control portion sets the entering vehicle as the preceding vehicle of the speed control portion when the entering vehicle is detected by the entering vehicle detection portion, the location determination portion sets a value smaller than the deviation amount between the travel trajectory of the entering vehicle and the travel trajectory of the preceding vehicle at the location where the speed control portion sets the entering vehicle as the preceding vehicle as the predetermined value, and the target trajectory setting portion sets the target travel trajectory of the host vehicle based on the travel trajectory of the preceding vehicle before entering of the entering vehicle until reaching the location determined by the location determination portion, and sets the target travel trajectory of the host vehicle based on the travel trajectory of the entering vehicle after the location determined by the location determination portion.

A third aspect of the invention is a driving assistance device that performs a driving assistance of a host vehicle in which the driving assistance device is disposed based on a travelling state of other vehicle detected at surroundings of the host vehicle. The driving assistance device includes: a speed control portion that sets any one of a preceding vehicle which travels in front of the host vehicle, and an entering vehicle which enters between the host vehicle and the preceding vehicle as an adjustment object vehicle, and controls a speed adjustment of the host vehicle, to make an inter-vehicle distance between the set adjustment object vehicle and the host vehicle become a predetermined distance; a target trajectory setting portion that acquires a travel trajectory of the preceding vehicle and the travel trajectory of the entering vehicle respectively, sets any one travel trajectory of the acquired travel trajectories as an object trajectory, and sets the target travel trajectory as the travel target of the host vehicle based on the set object trajectory; a steering control portion that controls an adjustment of a steer amount of the host vehicle, based on the target travel trajectory set by the target trajectory setting portion; and a location determination portion that determines a location where a deviation amount between the travel trajectory of the entering vehicle and the travel trajectory of the preceding vehicle becomes a predetermined value or below. The target trajectory setting portion takes an event of setting the adjustment object vehicle as the entering vehicle and an event of setting the object trajectory as the travel trajectory of the preceding vehicle as conditions, and switches the setting of the object trajectory from the travel trajectory of the preceding vehicle to the travel trajectory of the entering vehicle at the location determined by the location determination portion.

According to the above aspects, since the setting of the target travel trajectory is switched from the travel trajectory of the preceding vehicle to the travel trajectory the of entering vehicle at the location where the deviation amount between the travel trajectory of the preceding vehicle and the travel trajectory of the entering vehicle becomes the predetermined value or below; therefore, at the switched location, the deviation amount generated on the target travel trajectory also becomes the predetermined value or below. Therefore, the deviation amount generated on the target travel trajectory is restrained, thus, the control that intends to move the host vehicle in the vehicle width direction, the so-called unsteadiness, is restrained by the steering control. That is, even if the entering vehicle is set as the preceding vehicle in the speed control, in the steering control, the travel trajectory of the preceding vehicle is set as the target travel trajectory until the location where the deviation amount between the travel trajectory of the preceding vehicle and the travel trajectory of the entering vehicle becomes the predetermined value or below, and the travel trajectory of the entering vehicle is set as the target travel trajectory after the location where the deviation amount becomes the predetermined value or below. Therefore, the switch timing needed by the speed control (inter-vehicle distance control) and the switch timing needed by the steering control (travel trajectory control) can be suitably set. That is, the switch timing of the steer assistance is set when the travel position of the host vehicle reaches the location where the deviation amount becomes the predetermined value or below. In addition, since the control gain relating the steering control may not be reduced when switching the travel trajectory of the preceding vehicle and the travel trajectory of the entering vehicle, thus, there is no concern that the responsibility of the steering control reduces temporarily.

In the driving assistance device, the entering vehicle detection portion may detect the entering vehicle, at least based on the event that the interval between the target travel trajectory of the host vehicle and the vehicle body of the entering vehicle in a direction perpendicular to a travel direction of the host vehicle becomes a predetermined interval or below, and the predetermined value may be a value smaller than the predetermined interval in the direction perpendicular to the travel direction of the host vehicle.

In the driving assistance device, the speed control portion may switch the adjustment object vehicle from the preceding vehicle to the entering vehicle, at least based on an event that an interval between the target travel trajectory of the host vehicle and a vehicle body of the entering vehicle in a direction perpendicular to the travel direction of the host vehicle becomes the predetermined interval or below, and the predetermined value may be a value smaller than the predetermined interval in a direction perpendicular to the travel direction of the host vehicle.

According to the above configurations, the speed regulation regulated on the basis of the vehicle width and the lane width, and the steer amount regulation regulated on the basis of the target travel trajectory set on the basis of one point in the vehicle width direction are respectively switched under suitable situations based on these. Moreover, the predetermined interval may be determined based on the width of the vehicle body of the host vehicle, and the lane width where the host vehicle travels, etc.

In the driving assistance device, the location determination portion may obtain the deviation amount as a distance in a straight line which intersects with the travel trajectory of the preceding vehicle and the travel trajectory of the entering vehicle. According to this configuration, based on the straight line which intersects with the travel trajectory of the preceding vehicle and the travel trajectory of the entering vehicle, the calculation of the deviation amount is easy.

In the driving assistance device, the location determination portion may use the intersecting straight line that is perpendicular to any one of the travel trajectory of the preceding vehicle and the travel trajectory of the entering vehicle. According to this configuration, based on the straight line perpendicular to any one of the travel trajectory of the preceding vehicle and the travel trajectory of the entering vehicle, the calculation of the deviation is easy.

In the driving assistance device, it may further include a travel trajectory presuming portion that obtains a presuming travel trajectory that is presumed as the travel trajectory of the preceding vehicle. The location determination portion may use the presuming travel trajectory of the preceding vehicle as the travel trajectory of the preceding vehicle further after the location where the travel trajectory of the preceding vehicle cannot be acquired.

According to this configuration, even when the travel trajectory of the preceding vehicle cannot be acquired, the steering control is performed to follow the presuming travel trajectory of the preceding vehicle until reaching the location where the deviation amount between the presuming travel trajectory of the preceding vehicle and the travel trajectory of the entering vehicle becomes the predetermined value or below, it is capable to restrain the move of the host vehicle with respect to the deviation between the presuming travel trajectory of the preceding vehicle and the travel trajectory of the entering vehicle (reduce the unsteadiness).

In the driving assistance device, the travel trajectory presuming portion may obtain the travel trajectory approaching ratio of the travel trajectory of the entering vehicle with respect to the travel trajectory that can be acquired as the travel trajectory of the preceding vehicle, and obtains the presuming travel trajectory based on the obtained approaching ratio and the travel trajectory of the entering vehicle.

According to this configuration, even if when the travel trajectory of the preceding vehicle cannot be acquired, using the presuming travel trajectory presumed as the travel trajectory of the preceding vehicle based on the travel trajectory of the entering vehicle, the deviation amount with respect to the travel trajectory of the entering vehicle can be calculated and the location where the deviation amount becomes the predetermined value or below can be determined.

In the driving assistance device, the travel trajectory presuming portion may obtain a distance from the travel trajectory of the preceding vehicle and the travel trajectory of the entering vehicle as an inter-trajectory distance at the position where the travel trajectory of the preceding vehicle is acquired, and calculates the presuming travel trajectory by reducing the obtained inter-trajectory distance based on the approaching ratio of the travel trajectory of the entering vehicle.

According to this configuration, since the travel trajectory of the preceding vehicle is presumed based, on the approaching ratio of the entering vehicle, thus, the presumed presuming travel trajectory has high continuity with respect to the travel trajectory of the entering vehicle.

In the driving assistance device, the travel trajectory presuming portion may obtain the presuming travel trajectory based on at least one of the travel trajectory of an adjacent vehicle travels on a lane adjacent to the lane where the host vehicle travels, and a shape of a travel route in which the host vehicle travels.

According to this configuration, the presuming travel trajectory can be presumed using the travel trajectory of the preceding adjacent vehicle. In addition, the presuming travel trajectory can be presumed based on the area where the vehicle can travel defined by the lanes on the road in which the area is the travel route. In addition, the presuming accuracy can be improved by using a plurality of information to presume the presuming travel trajectory.

In the driving assistance device, the steering control portion may assist the host vehicle to move to a lane width direction opposite to an entering direction of the entering vehicle when it is determined that it is difficult to acquire the travel trajectory of the preceding vehicle due to an effect of the entering vehicle.

According to this configuration, since it is capable of delaying the timing that the entering vehicle overlaps with the range needed by the host vehicle for detecting the preceding vehicle or reducing the overlapping, thus, even the entering vehicle enters, the travel trajectory of the preceding vehicle can be acquired as long as possible. Specifically, when the entering vehicle is a large vehicle, there is a high possibility that the host vehicle cannot acquire the travel trajectory of the preceding vehicle; however, the host vehicle can acquire the travel trajectory of the preceding vehicle longer than usual.

In the driving assistance device, the steering control portion may determine that it is difficult to acquire the travel trajectory of the preceding vehicle due to the effect of the entering vehicle when the entering vehicle enters the width occupied by the host vehicle when travelling in a direction perpendicular to the travel direction of the host vehicle.

According to such a configuration, when the entering vehicle enters, moving the host vehicle moves with allowance, thus, the uncomfortable feeling of the user brought by the assistance of acquiring the trajectory of the preceding vehicle is decreased.

In the driving assistance device, the steering control portion may end assisting the host vehicle to move to the lane width direction opposite to the entering direction of the entering vehicle when the location determination portion determines the location where the deviation amount becomes the predetermined value or below.

According to the above configuration, a driving assistance is provided in which when it is not necessary to use the travel trajectory of the preceding vehicle for the target travel trajectory of the host vehicle, the travel route of the host vehicle returns to the target travel trajectory, and the uncomfortable feeling of the user is decreased.

DETAILED DESCRIPTION OF EMBODIMENTS

The First Embodiment

The first embodiment which embodies the driving assistance device will be described as follows by reference toFIGS. 1˜8.

Firstly, a general configuration of the driving assistance device300is described. As illustrated inFIG. 1, the driving assistance device300is applied to a vehicle10such as an automobile etc. The driving assistance device300provides the vehicle10with a preceding vehicle following assistance, as a driving assistance, that includes preceding vehicle following control which makes the host vehicle travel following the preceding vehicle20. In the vehicle10that travels following the preceding vehicle20based on the preceding vehicle following assistance, when an enterring vehicle30enters between the vehicle10and the preceding vehicle20, the assistance object is switched from the preceding vehicle20to the entering vehicle30at an appropriate timing in the preceding vehicle following assistance.

A general configuration of the preceding vehicle following assistance is described by reference toFIGS. 5˜8. As illustrated inFIG. 5, the vehicle10travels following the preceding vehicle20, by performing inter-vehicle distance assistance and travel trajectory assistance, in which the inter-vehicle distance assistance includes inter-vehicle distance control that ensures a predetermined inter-vehicle distance, and the travel trajectory assistance includes travel trajectory control that ensures travelling along the target travel trajectory. At this time, as illustrated inFIG. 6, according to the event that the entering vehicle30enters between the vehicle10and the preceding vehicle20from the right front in the travel direction of the vehicle10, the driving assistance device of the vehicle10switches the inter-vehicle distance adjustment object vehicle from the preceding vehicle20to the entering vehicle30. On the other hand, the distance, namely “deviation amount H1”, between the travel trajectory21of the preceding vehicle20and the travel trajectory31of the entering vehicle30is large. Therefore, if the target travel trajectory of the travel trajectory assistance is switched from the travel trajectory21of the preceding vehicle20to the travel trajectory31of the entering vehicle30at this position, the travel trajectory of the vehicle10will greatly vibrate in the direction of the entering vehicle30, which is the so-called vehicle10is pulled into the direction of the entering vehicle30. Therefore, as illustrated inFIGS. 6˜8, the driving assistance device300calculates the “deviation amount H1” which changes with entering of the entering vehicle30at any time, and detects the location where the “deviation amount H1” becomes within a “determination value Δh”. Then, the driving assistance device300performs travel trajectory assistance until the “deviation amount H1” becomes the “determination value Δh” or below, so as to travel along the travel trajectory21of the preceding vehicle20; and performs travel trajectory assistance after the “deviation amount H1” becomes the “determination value Δh” or below, so as to travel along the travel trajectory31of the entering vehicle30. In this way, the driving assistance device300adjusts the timing for switching the inter-vehicle distance adjustment object vehicle and the timing for switching the travel trajectory which becomes the object of the travel trajectory assistance to timings suitable to each assistance, respectively, thereby providing a preceding vehicle following assistance which restrains the movement (unsteadiness) of the host vehicle in the vehicle width direction.

Next, the configuration of the driving assistance device in this embodiment is described by reference toFIGS. 1-5. As illustrated inFIG. 1, the vehicle10includes a GPS device101, a vehicle-mounted camera102, a millimeter wave radar103, an acceleration sensor104, and a vehicle speed sensor105, to detect the travel state of the vehicle10. Besides, the vehicle10is also mounted with an accelerator pedal sensor106, a brake pedal sensor107, and a steer angle sensor108etc. The GPS device101, the vehicle-mounted camera102, the millimeter wave radar103, the acceleration sensor104, the vehicle speed sensor105, the accelerator pedal sensor106, the brake pedal sensor107and the steer angle sensor108are connected to a vehicle-mounted control device200which performs various vehicle controls via a vehicle-mounted network. Furthermore, as the vehicle-mounted network, a CAN (controller area network), etc may be used.

The GPS device101receives signals from GPS satellites and detects the position of the vehicle10as longitude and latitude based on the signals received from the GPS satellite. Then, the GPS device101outputs the detected position information that shows the position (longitude and latitude) of the vehicle10to the vehicle-mounted control device200. As such, based on the position information, the vehicle-mounted control device200can obtain the required information of road and region from the map information database, or receive route guidance from a navigation system112.

The vehicle-mounted camera102shoots photos of the surrounding environments of the vehicle10and outputs the shot image data to the vehicle-mounted control device200. The images shot by the vehicle-mounted camera102include the images of lanes of the road on which the vehicle10travels, the road profile, the road facilities such as guard rails and side walls of the road, as well as other vehicles travelling in the surrounding area of the vehicle10. In such other vehicles, images about the preceding vehicle20that travels in the front in the travel direction are included. Furthermore, in such other vehicles, images of the so-called entering vehicle30that changes its travel lane in front of the travelling vehicle10or enters between the vehicle10and the preceding vehicle20are included. The vehicle-mounted control device200detects the external circumstances, such as other vehicle travelling in the surrounding area of the vehicle10, the relative position and relative speed of the other vehicle relative to the vehicle10, the travel lane of the vehicle10, and the adjacent lanes adjacent to the travel lane of the vehicle10, based on the image identification process of the shot images.

The millimeter wave radar103detects the objects exist around the vehicle10using the electric wave of millimeter band, and outputs the signals corresponding to the detection result to the vehicle-mounted control device200. The millimeter wave radar103can also detect vehicles that approach the vehicle10. For example, the millimeter wave radar103can detect the preceding vehicle20, and the entering vehicle30that enters towards the front of the vehicle10, etc. Besides, since the difference between the speeds of the preceding vehicle20, the entering vehicle30and the vehicle10is small, thus it is determined that they are vehicles. In the vehicle-mounted control device200, the external circumstances are detected according to the detection result of the millimeter wave radar103. For example, the vehicle-mounted control device200calculates the inter-vehicle distance between the vehicle10and the preceding vehicle20and the relative speed; or detects the entering vehicle30that approaches and is different from the preceding vehicle20, and calculates the inter-vehicle distance between the vehicle10and the entering vehicle30as well as the relative speed.

The acceleration sensor104detects the acceleration of the vehicle10and outputs the signal corresponding to the detected acceleration to the vehicle-mounted control device200. The vehicle-mounted control device20calculates the acceleration of the vehicle10, based on the signal corresponding to the acceleration.

The speed sensor105detects the rotation speed of the wheels of the vehicle10and outputs a signal corresponding to the detected rotation speed to the vehicle-mounted control device200. The vehicle-mounted control device200calculates the speed of the vehicle10, based on the rotation speed.

The accelerator pedal sensor106detects the operation amount of the accelerator pedal performed by the driver, and outputs a signal corresponding to the detected operation amount of the accelerator pedal to the vehicle-mounted control device200. The vehicle-mounted control device200calculates an acceleration of the vehicle10, based on the operation amount of the accelerator pedal.

The brake pedal sensor107detects the operation amount of the brake pedal performed by the driver, and outputs a signal corresponding to the detected operation amount of the brake pedal to the vehicle-mounted control device200. The vehicle-mounted control device200calculates a deceleration of the vehicle10, based on the operation amount of the brake pedal.

The steer angle sensor108detects the steer angle of the steering and outputs a signal corresponding to the detected steer angle to the vehicle-mounted control device200. The vehicle-mounted control device200calculates the travel direction of the vehicle10, based on the steer angle.

The vehicle10includes a map information database111registered with map data. The map information database111is connected to the vehicle-mounted control device200such that the data can be read and written. Map data includes geography-related data, such as the road etc. In map data, data that can display geography and information relating to positions such as longitude and latitude are registered. The map information database141includes the locations of specific traffic factors such as crossroads, traffic lights and curves, as well as road information such as lane number, lane width, and curvature of the curve and slopes. In addition, various data such as road data that includes the type of the road, and crossroad data showing the crossroad information, etc. may also be included in the map information database111.

The vehicle10includes a navigation system112and a display device113. The navigation system112and the display device113are electrically connected to the vehicle-mounted control device200.

The navigation system112acquires present location of the vehicle10(longitude and latitude) from the vehicle-mounted control device200in which the detection result of the GPS device101is input. Furthermore, the navigation system112searches for a travel route from the present position of the vehicle10to a destination, by referring the map information database111. Furthermore, the navigation system112outputs information showing the searched travel route, moving time, etc. to the vehicle-mounted control device200; and outputs to the display device113consisting of LCD display provided inside the vehicle body via the vehicle-mounted control device200.

The vehicle10includes a meter control device114for controlling the display state of the meter displayed on an installment panel provided on a dash board. The meter control device114is electrically connected to the vehicle-mounted control device200. The meter control device114acquires data that shows the vehicle speed, from the vehicle-mounted control device200, and performs visible display of the vehicle speed based on the acquired data.

The vehicle10includes: an acceleration control device115for controlling the driving state of an engine; a brake control device116for controlling the acting state of the brake, and a steering control device117for controlling the steering state of the steering. The acceleration control device115, the brake control device116, and the steering control device117are electrically connected to the vehicle-mounted control device200.

The acceleration control device115controls the driving state of the engine, based on a control amount calculated by the vehicle-mounted control device200according to the detection value of the accelerator pedal sensor106. Furthermore, the acceleration control device115also can control the driving state of the engine, according to a control amount of the engine calculated by the vehicle-mounted control device based on the driving assistance.

The brake control device116controls the acting state of the brake, based on a control amount of the brake calculated by the vehicle-mounted control device200according to the detection value of the brake pedal sensor107. Furthermore, the brake control device116can also control the acting state of the brake, based on a control amount of the brake calculated by the vehicle-mounted control device200according to the driving assistance.

The steering control device117controls the steering state of the steering, based on a control amount of the steer angle calculated by the vehicle-mounted control device200according to a detection value of the steer angle sensor108. Furthermore, the steering control device117can also control the steering state of the steering, according to a control amount of the steer angle calculated by the vehicle-mounted control device200based on the driving assistance.

By such a configuration, for example, the signal used for adjusting speed from the vehicle-mounted control device200is input to the display device113, thus, an indication relates to the acceleration/deceleration of the vehicle speed of the vehicle10can be displayed on the display device113; or the signal is input to the acceleration control device115, thus, the acceleration control device115can perform fine-tuning to the speed of the vehicle10. Furthermore, for example, the signal used for adjusting brake from the vehicle-mounted control device200is input to the display device113, thus, an indication relates to the brake operation of the vehicle10can be displayed on the display device113; or the signal is input to the brake control device116, thus, the brake control device116can decrease the speed of the vehicle10. Furthermore, for example, the signal used for adjusting steering amount from the vehicle-mounted control device200is input to the display device113, thus, an indication relates to the steering amount of the vehicle10can be displayed on the display device113; or the signal is input to the steering control device117, thus, the steering control device117can perform fine-tuning to the steer angle of the vehicle10.

The vehicle-mounted control device200is a control device used for various controls of the vehicle10, for example, the vehicle-mounted control device200is a control device that includes a driving system, a travelling system, a vehicle body system, or an information device system, etc. as the control objects. The vehicle-mounted control device200is the so-called ECU (electronic control unit), which is configured to include a micro computer with a calculation unit and a storage unit. The calculation unit is the so-call CPU etc., for performing calculation process of a control program. The storage unit includes Read Only Memory (ROM) storing the control program or data, and Random Access Memory (RAM) temporarily storing the calculation results of the calculation unit; and the storage unit is configured by including non-volatile memory medium such as hard disk or EEPROM such as flash memory for storing large amount of data. Therefore, the vehicle-mounted control device200reads the control program and various parameters storing in the storage unit to the calculation unit and performs operation process, thereby providing predetermined functions to the control object and performing control of the control object.

In this embodiment, the vehicle-mounted control device200includes a driving assistance device300for performing driving assistance. As illustrated inFIG. 2, the driving assistance device300is input with a signal relating to the driving assistance from the vehicle-mounted control device200, and performs driving assistance relating to deceleration, acceleration and steering, etc., according to the input signal relating to the driving assistance. For example, the driving assistance device300is input with vehicle speed, inter-vehicle distance, following assistance setting information, acceleration operation information, brake operation information, steering operation information, information of other vehicles, road information, and structure detection information, etc., from the vehicle-mounted control device200. Furthermore, the driving assistance device300outputs HMI (Human Machine Interface) information, acceleration control information, brake control information, and steering control information, etc.

The vehicle-mounted control device200is stored with a control program for achieving the functions of the driving assistance device300, by performing the control program, the driving assistance device300is provided. Moreover, as parameters, various values such as “determination value Δh” are set as needed.

In this embodiment, the driving assistance device300performs a preceding vehicle following assistance which enables the vehicle10to travel by following the preceding vehicle20. The preceding vehicle following assistance is an assistance performed by at least the combination of an inter-vehicle distance assistance which maintains an inter-vehicle distance between the vehicle10and the preceding vehicle20, and a travel trajectory assistance which makes the vehicle10travel along the target travel trajectory (target travel route). Moreover, the inter-vehicle distance assistance includes speed adjustment assistance using the speed adjustment to regulate the error with respect to a target interval.

The driving assistance device300includes a preceding vehicle detection portion310, an entering vehicle detection portion320, a speed assistance portion330function as a speed control portion, a preceding vehicle travel trajectory acquisition portion340, an entering vehicle travel trajectory acquisition portion350, a target trajectory setting portion370, a steer assistance portion380function as a steering control portion, and a location determination portion360. The preceding vehicle detection portion310, the entering vehicle detection portion320, the speed assistance portion330, the preceding vehicle travel trajectory acquisition portion340, the entering vehicle travel trajectory acquisition portion350, the target trajectory setting portion370, the steer assistance portion380and the location determination portion360exhibit their functions by performing the control program of the vehicle-mounted control device200.

The preceding vehicle detection portion310detects the preceding vehicle20, inputs information such as the relative position and the relative speed with respect to other vehicle detected by the vehicle-mounted control device200using an image recognition process, determines the preceding vehicle20based on the above information, and calculates the inter-vehicle distance and relative speed with respect to the preceding vehicle20.

The entering vehicle detection portion320detects the entering vehicle30, inputs information such as the relative position and the relative speed with respect to other vehicle detected by the vehicle-mounted control device200using image recognition process, determines the entering vehicle30based on above information, and calculates the inter-vehicle distance and relative speed with respect to the entering vehicle30. Specifically, the entering vehicle detection portion320detects the other vehicle as the entering vehicle30, based on the event that an interval between the target travel trajectory and the body of the other vehicle falls within the predetermined interval. For example, whether the interval between the target travel trajectory and the entering vehicle30changes from a position where it is larger than a half equivalence of the width of the lane on which the vehicle10travels to a position where it is equals to or smaller than a half equivalence of the width of the lane on which the vehicle10travels can be detected.

In this embodiment, the vehicle10travels in a manner that the center in the vehicle width direction is along the target travel trajectory. Therefore, the predetermined interval is determined based on the width defined based on the vehicle10, such as the vehicle body width of the vehicle10, etc.; and the width defined based on the road, such as the lane width on which the vehicle10is travelling, to be able to detect the entering vehicle. For example, the predetermined interval is determined as being able to at least guarantee an interval of the vehicle body width of the vehicle10or above, that is a size of half of the vehicle body width or above. Moreover, the interval between the target travel trajectory of the vehicle10and the body of the entering vehicle30is preferably an interval perpendicular to a travel direction of the vehicle10. Moreover, the entering vehicle detection portion320ends the detection of the detected entering vehicle30, by setting the detected entering vehicle30as the preceding vehicle of the preceding vehicle following assistance, etc.

The speed assistance portion330assists the speed adjustment of the vehicle10, so as to make the inter-vehicle distance between the adjustment object vehicle and the vehicle10a proper inter-vehicle distance, or make the speed a proper speed for maintaining a proper inter-vehicle distance or above, with respect to the adjustment object vehicle selected from any one of the preceding vehicle20and the entering vehicle30. For example, the speed assistance portion330can control the speed adjustment of the vehicle10by transmitting the adjusted speed to the acceleration control device115and the brake control device116. The speed assistance portion330usually selects the preceding vehicle20as the adjustment object vehicle; on the other hand, selects the entering vehicle30as the adjustment object vehicle according to the event that the entering vehicle30is detected. That is, the speed assistance portion330changes the adjustment object vehicle from the preceding vehicle20to the entering vehicle30according to the event that the entering vehicle30is detected, at this time point, in the speed assistance portion330selects the entering vehicle30before changing of the adjustment object vehicle as the “new preceding vehicle”.

The preceding vehicle travel trajectory acquisition portion340acquires the travel trajectory21of the preceding vehicle20, inputs information such as the relative position and the relative speed with respect to the other vehicle detected by the vehicle-mounted control device200using the image recognition process, as for the preceding vehicle20determined based on the above information, acquires the travel trajectory21of the preceding vehicle20. The detection of the preceding vehicle20can be performed, for example, using the same process with the preceding vehicle detection portion310.

The entering vehicle travel trajectory acquisition portion350acquires the travel trajectory31of the entering vehicle30, inputs information such as the relative position and the relative speed with respect to the other vehicle detected by the vehicle-mounted control device200using the image recognition process, detects the entering vehicle30based on the above information, and acquires the travel trajectory31of the entering vehicle30. The detection of the entering vehicle30can be performed, for example, using the same process with the entering vehicle detection portion320.

Herein, the entering vehicle travel trajectory acquisition portion350may also acquire the travel trajectory of the other vehicle before the entering vehicle30is detected. The entering vehicle travel trajectory acquisition portion350may also selects one or more of the vehicles among the other vehicles which travel between the side of the vehicle10and the preceding vehicle20in the adjacent lane of the vehicle10as entering candidate vehicles that may become the entering vehicle30, and acquires travel trajectories of these entering candidate vehicles. Moreover, setting the travel trajectory31of the entering vehicle30acquired by the entering vehicle travel trajectory acquisition portion350as the target travel trajectory of the preceding vehicle following assistance, etc., thus, the entering vehicle travel trajectory acquisition portion350ends the acquirement of the travel trajectory31of the entering vehicle30, by making the preceding vehicle travel trajectory acquisition portion340inherits the acquirement.

The location determination portion360is input with the travel trajectory21of the preceding vehicle20acquired by the preceding vehicle travel trajectory acquisition portion340, and is input with the travel trajectory31of the entering vehicle30acquired by the entering vehicle travel trajectory acquisition portion350. The location determination portion360compares the travel trajectory21of the preceding vehicle20with the travel trajectory31of the entering vehicle30, and determines a location where the travel trajectory31of the entering vehicle30approaches the travel trajectory21of the preceding vehicle20within a predetermined “determination value Δh”. That is, the location determination portion360determines a location where the “deviation amount H1” between the travel trajectory21of the preceding vehicle20and the travel trajectory31of the entering vehicle30becomes the predetermined “determination value Δh” or below. The predetermined “determination value Δh” is a value with a degree of the following amount, for example, even the target travel trajectory is switched from the travel trajectory21of the preceding vehicle20to the travel trajectory31of the entering vehicle30, the steering amount of the vehicle10can also restrain the discomfort feeling of the users.

That is, the “determination value Δh” is a value, in a direction perpendicular to the travel direction of the vehicle10, smaller than the predetermined interval used by the entering vehicle detection portion320for detecting the entering vehicle30. The target trajectory setting portion370is input with: the travel trajectory21of the preceding vehicle20acquired by the preceding vehicle travel trajectory acquisition portion340; the travel trajectory31of the entering vehicle30acquired by the entering vehicle travel trajectory acquisition portion350; and the location determined by the location determination portion360. The target trajectory setting portion370usually sets the travel trajectory21of the preceding vehicle20acquired by the preceding vehicle travel trajectory acquisition portion340as the target travel trajectory. On the other hand, if the target trajectory setting portion370is input with the location determined by the location determination portion360, the target trajectory setting portion370sets the target travel trajectory based on the travel trajectory21of the preceding vehicle20before the entering of the entering vehicle30, until the input determined location; and after the input determined location, sets the target travel trajectory based on the travel trajectory31of the entering vehicle30. That is, at the location where the distance between the travel trajectory21of the preceding vehicle20and the travel trajectory31of the entering vehicle30, which is the “deviation amount H1” becomes the “determination value Δh” or below, the target trajectory setting portion370changes the travel trajectory which is set as the target travel trajectory from travel trajectory21of the preceding vehicle20to the travel trajectory31of the entering vehicle30. Thus the set target travel trajectory enables the “deviation amount H1” of the trajectory generated at a determined location which is the joint of the travel trajectory21of the preceding vehicle20and the travel trajectory31of the entering vehicle30equal to or smaller than, for example, the “determination value Δh”. That is, at the determined location, the target trajectory setting portion370changes the travel trajectory which is set as the target travel trajectory from the travel trajectory21of the preceding vehicle20to the trajectory31of the entering vehicle30; at this position, the target trajectory setting portion370changes the object of the travel trajectory, which is set as the target travel trajectory, from the travel trajectory21of the preceding vehicle20before the entering of the entering vehicle30to the travel trajectory31of the entering vehicle30.

The steer assistance portion380assists the adjustment to the steer amount of the vehicle10, such that the travel trajectory of the vehicle10travels along the target travel trajectory; in other words, the vehicle10traces along the target travel trajectory. More specifically, the steer assistance portion380adjusts the steer amount, to make the vehicle10travel in a manner that the center in the vehicle width direction of the vehicle10is along the target travel trajectory. The steer assistance portion380transmits the information relating to the steer amount needed by the travel trajectory assistance of the vehicle10to users, or to the steering control device117, based on the error between the travel position of the vehicle10and the target travel trajectory generated by the target trajectory setting portion370. For example, the steer assistance portion380transmits the information relating to the adjusted steer amount to the steering control device117, thereby being capable of controlling the adjustment to the steer amount.

Herein, in this embodiment, the inter-vehicle distance assistance portion301consisting of the preceding vehicle detection portion310, the entering vehicle detection portion320, and speed assistance portion330is used to perform a speed adjustment assistance. Furthermore, the target trajectory assistance portion302consisting of the preceding vehicle travel trajectory acquisition portion340, the entering vehicle travel trajectory acquisition portion350, the location determination portion360, the target trajectory setting portion370, and the steer assistance portion380is used to perform a travel trajectory assistance.

Next, the steps of the preceding vehicle following assistance are described in reference withFIGS. 3-4. Firstly, it is determined whether the preceding vehicle following assistance can be performed by taking the vehicle10is travelling etc. as conditions. As illustrated inFIG. 3, if the vehicle10starts to travel, the driving assistance device300determines whether the switch (not shown) indicating the performing of the preceding vehicle following assistance is turned on (Step S1). The state of the switch indicating the performing of the preceding vehicle following assistance is input from the vehicle-mounted control device200as the following assistance setting information. When it is determined that the switch indicating the performing of the preceding vehicle following assistance is turned off (NO in Step S1), the driving assistance device300returns the process to Step S1at a predetermined time interval. That is, it is determined again whether the switch indicating the performing of the preceding vehicle following assistance is turned on (Step S1).

On the other hand, when it is determined that the switch indicating the performing of the preceding vehicle following assistance is turned on (YES in Step S1), the driving assistance device300performs the process of generating the target travel trajectory (Step S2). Then, if the process of generating the target travel trajectory ends, the driving assistance device300determines whether the switch indicating the performing of the preceding vehicle following assistance is turned off (Step S3).

Then, when it is determined that the switch indicating the performing of the preceding vehicle following assistance is not turned off (NO in Step S3), the driving assistance device300returns the process to Step S2at a predetermined time interval. That is, the process of generating the target travel trajectory is repeated (Step S2). Furthermore, when it is determined that the switch indicating the performing of the preceding vehicle following assistance is turned off (YES in Step S3), the driving assistance device300clears the target travel trajectory (Step S4), and ends the preceding vehicle following assistance. Therefore, if the target travel trajectory is cleared, the fact of ending the preceding vehicle following assistance is notified to the user by the display of the display device113, thus the user can acknowledge that it is not in the performing of the driving assistance. Moreover, whether the switch indicating the performing of the preceding vehicle following assistance is turned on or turned off, the preceding vehicle following assistance ends due to the situation that the vehicle10is not travelling.

Next, the process of generating the target travel trajectory (Step S2) is described in details. As illustrated inFIGS. 4A and 4B, if the process of generating the target travel trajectory is started, then the driving assistance device300determines whether the preceding vehicle20is present (Step S10). When it is determined that the preceding vehicle20is absent (NO in Step S10), the driving assistance device300clears the target travel trajectory (Step S11), and ends the process of generating the target travel trajectory.

On the other hand, when it is determined that the preceding vehicle20is present (YES in Step S10), the driving assistance device300determines whether to perform setting the target travel trajectory (Step S12). Performing setting the target travel trajectory is determined by setting with (not cleared) the target travel trajectory. When it is determined that it is not setting the target travel trajectory (NO in Step S12), the driving assistance device300determines whether the travel trajectory21of the preceding vehicle20is present according to the travel position of the vehicle10(Step S13). When it is determined that the travel trajectory21of the preceding vehicle20is absent according to the travel position of the vehicle10(NO in Step S13), the driving assistance device300clears the target travel trajectory (Step S11), and ends the process of generating the target travel trajectory. On the other hand, when it is determined that the travel trajectory21of the preceding vehicle20is present according to the travel position of the vehicle10(YES in Step S13), the driving assistance device300sets the travel trajectory21of the preceding vehicle20as the target travel trajectory (Step S14), and ends the process of generating the target travel trajectory.

Furthermore, when it is determined that it is during the setting of the target travel trajectory (YES in Step S12), the driving assistance device300determines whether the adjustment object vehicle of the speed assistance portion330is switched to other vehicle (Step S15).

Then, when it is determined that the adjustment object vehicle of the speed assistance portion330is not switched to other vehicle (NO in Step S15), the driving assistance device300determines whether it is during the determining of the “deviation amount” (Step S26). Whether or not it is during the determining of the “deviation amount” is determined by setting a flag of determining the “deviation amount”, such as setting the flag to “1”. When it is determined that it is not during the determining of the “deviation amount” (NO in Step S26), the driving assistance device300sets the target travel trajectory based on the travel trajectory21of the preceding vehicle20(Step S27), and ends the process of generating the target travel trajectory. On the other hand, when it is determined that it is during the determining of the “deviation amount” (YES in Step S26), the driving assistance device300proceeds the process to Step S18as described in the following.

Furthermore, when it is determined that the adjustment object vehicle of the speed assistance portion330is changed to other vehicle (YES in Step S15), the driving assistance device300determines whether the adjustment object vehicle of the speed assistance portion330is switched from the preceding vehicle20to the entering vehicle30(Step S16).

When it is determined that the adjustment object vehicle of the speed assistance portion330is changed from the preceding vehicle20to the entering vehicle30(NO in Step S16), the driving assistance device300clears the target travel trajectory (Step S25), and ends the process of generating the target travel trajectory. This is the following circumstance: the other vehicle other than the entering vehicle30becomes the preceding vehicle20, because the vehicle10changes its lane, etc.

On the other hand, when it is determined that the adjustment object vehicle of the speed assistance portion330is changed from the preceding vehicle20to the entering vehicle30(YES in Step S16), the driving assistance device300sets a flag of determining the “deviation amount” (Step S17).

The driving assistance device300determines whether the travel trajectory21of the preceding vehicle20before the entering of the entering vehicle30is acquired (Step S18). When it is determined that the travel trajectory21of the preceding vehicle20before the entering of the entering vehicle30is acquired (YES in Step S18), the driving assistance device300sets the target travel trajectory based on the travel trajectory21of the preceding vehicle20(Step S19), and proceeds the process to Step S20as described in the following. On the other hand, when it is determined that the travel trajectory21of the preceding vehicle20before the entering of the entering vehicle30is not acquired (NO in Step S18), the driving assistance device300proceeds the process to Step S20as described in the following.

The driving assistance device300determines whether the “deviation amount H1” between the travel trajectory21of the preceding vehicle20and the travel trajectory31of the entering vehicle30can be calculated (Step S20). When it is determined that the “deviation amount H1” between the travel trajectory21of the preceding vehicle20and the travel trajectory31of the entering vehicle30cannot be calculated (NO in Step S20), the driving assistance device300sets the travel trajectory31of the entering vehicle30as the target travel trajectory (Step S21). Then, the flag of determining the “deviation amount” is unset (Step S24) and the process of generating the target travel trajectory ends.

On the other hand, when it is determined that the “deviation amount H1” between the travel trajectory21of the preceding vehicle20and the travel trajectory31of the entering vehicle30can be calculated (YES in Step S20), the driving assistance device300calculates the “deviation amount H1” between the travel trajectory21of the preceding vehicle20and the travel trajectory31of the entering vehicle30(Step S22). Then, the driving assistance device300determines whether the “deviation amount H1” is the “determination value Δh” or below (Step S23). When it is determined that the “deviation amount H1” is not the “determination value Δh” or below (NO in Step S23), the driving assistance device300ends the process of generating the target travel trajectory.

Furthermore, when it is determined that the “deviation amount H1” is the “determination value Δh” or below (YES in Step S23), the driving assistance device300unsets the flag of determining the “deviation amount” (Step S24), and ends the process of generating the target travel trajectory.

Furthermore, by repeating the above process of generating the target travel trajectory, based on the event of setting the travel trajectory21of the preceding vehicle20as the target travel trajectory, and the event that the “deviation amount H1” becomes the ‘determination value Δh” or below, the travel trajectory31of the entering vehicle30is set as the target travel trajectory.

By reference toFIGS. 5-8, the effect of this embodiment is described. As illustrated inFIG. 5, the vehicle10travelling on the lane R1sets the vehicle which travels in the front in the travel direction of the vehicle10and closest to the vehicle10as the preceding vehicle20. Furthermore, in the vehicle10, the preceding vehicle following assistance is performed with respect to the preceding vehicle20. That is, in the vehicle10, the inter-vehicle distance assistance is performed with respect to the preceding vehicle20, and the travel-trajectory assistance is performed with respect to the travel trajectory21of the preceding vehicle20. Furthermore, in the adjacent lane, the entering vehicle30is travelling in a same direction with the travel direction of the vehicle10. The vehicle10acquires the travel trajectory31with respect to the entering vehicle30, as the entering candidate vehicle.

As illustrated inFIG. 6, based on the event that the other vehicle (entering vehicle30) enters the travelling lane R1, the vehicle10detects the other vehicle that enters between the vehicle10and the preceding vehicle20as the entering vehicle30. At the time that the entering vehicle30is detected, in the inter-vehicle distance assistance, the adjustment object vehicle as the assistance object is changed from the preceding vehicle20to the entering vehicle3G from the viewpoint of preventing rear-end collision.

On the other hand, at the time that the entering vehicle30is detected, in the travel trajectory assistance, the “deviation amount H1” between the travel trajectory21of the preceding vehicle20and the travel trajectory31of the entering vehicle30is calculated. The “deviation amount H1” is a distance from the predetermined position of the travel trajectory31of the entering vehicle30to the travel trajectory21of the preceding vehicle20. For example, the “deviation amount H1” is the shortest distance from the predetermined position of the travel trajectory31of the entering vehicle30to the travel trajectory21of the preceding vehicle20, it is obtained as a vertical line from the predetermined position of the travel trajectory31of the entering vehicle30to the travel trajectory21of the preceding vehicle20, that is, the length of the vertical line. Furthermore, it is a defined line; the vertical line can also be replaced with a line which intersects with the predetermined position of the travel trajectory31of the entering vehicle30and the travel trajectory21of the preceding vehicle20. Moreover, the vehicle10compares the obtained “deviation amount H1” with the “determination value Δh”, and determines whether the “deviation amount H1” is within the “determination value Δh”. Furthermore, inFIG. 6, it is determined that the “deviation amount H1” is not within the “determination value Δh”, the target travel trajectory is continuously set based on the travel trajectory21of the preceding vehicle20.

As illustrated inFIG. 7, when the entering of the entering vehicle30between the vehicle10and the preceding vehicle20proceeds, in the travel trajectory assistance, the “deviation amount H1” is re-calculated (updated), and whether the re-calculated “deviation amount H1” is within the “determination value Δh” is determined at any time. Furthermore, in the aspect illustrated inFIG. 7, it is determined that the “deviation amount H1” is not within the “determination value Δh”, the target travel trajectory is continuously set based on the travel trajectory21of the preceding vehicle20.

As illustrated inFIG. 8, when the entering of the entering vehicle30between the vehicle10and the preceding vehicle20further proceeds, in the travel trajectory assistance, it is determined whether the re-calculated “deviation amount H1” is within the “determination value Δh”. Then, in the aspect illustrated byFIG. 8, it is determined that the “deviation amount H1” is within the “determination value Δh”, and the setting of the target travel trajectory is changed from the travel trajectory21of the preceding vehicle20to the travel trajectory31of the entering vehicle30, and is set based on the travel trajectory31of the entering vehicle30. Therefore, before a position where the “deviation amount H1” is the “determination value Δh” or below in the travel direction of the vehicle10, the target travel trajectory is set as the travel trajectory21of the preceding vehicle20; and further from the position where the “deviation amount H1” becomes the “determination value Δh” or below in the travel direction of the vehicle10, the target travel trajectory is set as the travel trajectory31of the entering vehicle30. Therefore, the travel position of the vehicle10reaches the position where the “deviation amount H1” becomes the “determination value Δh” or below, thereby the setting of the target travel trajectory is switched from the travel trajectory21of the preceding vehicle20to the travel trajectory31of the entering vehicle30. Moreover, since the entering vehicle30enters between the vehicle10and the preceding vehicle20, the preceding vehicle20cannot be seen from the vehicle10, thus, the travel trajectory21of the preceding vehicle20further from the location22cannot be acquired.

Herein, in this embodiment, since the travel trajectory set as the target travel trajectory changes from the travel trajectory of the preceding vehicle20to that of the entering vehicle30with a small deviation, thus, even if the set travel trajectory is changed, the control gain relating to the following the target travel trajectory may not be changed.

According to this embodiment, a driving assistance device is provided in which a movement (unsteadiness) in the vehicle width direction of the host vehicle can be restrained, even when the entering vehicle30enters between the vehicle10and the preceding vehicle20.

As described above, according to the driving assistance device of this embodiment, the following effect can be achieved. (1) At the position where the deviation amount H1between the travel trajectory21of the preceding vehicle20and the travel trajectory31of the entering vehicle30becomes the predetermined determination value Δh or below, the setting of the target travel trajectory11is changed from the travel trajectory21of the preceding vehicle20to the travel trajectory31of the entering vehicle30; therefore, at such changed position, the deviation amount H1generated on the target travel trajectory11becomes the predetermined determination value Δh or below. Thus, since the deviation amount H1generated on the target travel trajectory11is restrained; therefore, the assistance that intends to move the vehicle10in the vehicle width direction, which is the so-called unsteadiness, is restrained by the steer assistance. That is, even if the entering vehicle30is set as the preceding vehicle20in the speed assistance, in the steer assistance, until the position where the deviation amount H1between the travel trajectory21of the preceding vehicle20and the travel trajectory31of the entering vehicle30becomes the predetermined determination value Δh or below, the travel trajectory21of the preceding vehicle20is set as the target travel trajectory11, and after the position where the deviation amount H1becomes the predetermined determination value Δh or below, the travel trajectory31of the entering vehicle30is set as the target travel trajectory11. Thus, the switching time needed by the speed assistance (inter-vehicle distance assistance), and the switching time needed by steer assistance (travel trajectory assistance) can be properly set. That is, the switching time of the steer assistance is set when the travel position of the vehicle10reaches the position where the “deviation amount H1” becomes the “determination value Δh” or below. Furthermore, when switching between the travel trajectory21of the preceding vehicle20and the travel trajectory31of the entering vehicle30, the control gain relating to the steer assistance may not be decreased, thus, the responsibility of the steer assistance will not be decreased temporarily.

(2) The speed adjustment adjusted based on the vehicle width and lane width, and the steer amount adjustment adjusted based on the target travel trajectory11which set one point in the vehicle width direction as a basis, are switched under a circumstance that suits the basis, respectively. Furthermore, the “determination value Δh” can be determined based on the width of the vehicle body of the host vehicle, and the lane width of the lane on which the host vehicle is travelling, etc.

(3) According to the straight line which intersects with the travel trajectory21of the preceding vehicle20and the travel trajectory31of the entering vehicle30, the deviation amount H1can be easily calculated. (4) According to the straight line perpendicular to the travel trajectory21of the preceding vehicle20, the deviation amount can be calculated more easily.

The Second Embodiment

By reference toFIGS. 9-18, the second embodiment which embodies the driving assistance device is described.

In this embodiment, when it is determined that the travel trajectory21of the preceding vehicle20cannot be acquired further from the location where the “deviation amount H1” becomes within the “determination value Δh”, a presuming travel trajectory35is used, this configuration is different from the configuration of determining the “deviation amount H1” in the first embodiment, but the other configurations are the same. Therefore, the configuration different from the first embodiment is mainly described in the following; and as for the same configuration with the first embodiment, same reference numerals are used; and in order to make it convenient to be described, the detailed descriptions are omitted. Moreover, the same processes in the flowcharts ofFIGS. 10A, 10B and 11, and in the flowchart ofFIGS. 4A and 4Bof the first embodiment are marked with the same reference numerals.

As illustrated inFIG. 9, if the entering of the entering vehicle30enters between the vehicle10and the preceding vehicle20proceeds, in the travel trajectory assistance, it is determined whether the “deviation amount H1” calculated based on the travel trajectory21of the preceding vehicle20and the travel trajectory31of the entering vehicle30is within the “determination value Δh” at any time. However, although it is determined that the “deviation amount H1” is not within the “determination value Δh”, sometimes the preceding vehicle20cannot be seen from the vehicle10, thus, the travel trajectory21of the preceding vehicle20further from the location22cannot be acquired. Therefore, the “deviation amount H1” cannot be calculated, in the travel trajectory assistance, it is concerned that the switching from the travel trajectory21of the preceding vehicle20to the travel trajectory31of the entering vehicle30is not performed properly.

Therefore, in this embodiment, in the travel trajectory assistance, when the travel trajectory21of the preceding vehicle20cannot be acquired, as the trajectory continued further at the travel trajectory21of the preceding vehicle20, the presuming travel trajectory35is presumed. That is, a travel trajectory presuming portion390which obtains the presuming travel trajectory35presumed as the travel trajectory21of the preceding vehicle20is also included, further from the position where the travel trajectory21of the preceding vehicle20cannot be acquired, the location determination portion360uses presuming travel trajectory35of the preceding vehicle20as the travel trajectory21of the preceding vehicle20. Moreover, in the travel trajectory assistance, a “presuming deviation amount H2” from the presumed presuming travel trajectory35and the travel trajectory31of the entering vehicle30for comparing with the “determination value Δh” is calculated.

Firstly, the general configuration of this embodiment is described by reference toFIGS. 12-15. As illustrated inFIG. 12, the vehicle10includes a travel trajectory presuming portion390in the driving assistance device300. The vehicle10performs the inter-vehicle distance assistance and the travel trajectory assistance, thus, travels following the preceding vehicle20. At this time, as illustrated inFIG. 13, according to the event that the entering vehicle30enters from the right front of the travel direction of the vehicle10between the vehicle10and the preceding vehicle20to a lane R2, the driving assistance device of the vehicle10switches the inter-vehicle distance assistance object vehicle from the preceding vehicle20to the entering vehicle30. On the other hand, a distance between the travel trajectory21of the preceding vehicle20and the travel trajectory31of the entering vehicle30, which is the deviation amount, is large; therefore, at this position, the target travel trajectory of the travel trajectory assistance does not switch from the travel trajectory21of the preceding vehicle20to the travel trajectory31of the entering vehicle30.

Next, as illustrated inFIG. 14, the vehicle10determines the location T0where the entering vehicle30enters the lane R2. Moreover, as illustrated inFIG. 15, the vehicle10determines the position corresponding to the location22where the travel trajectory21of the preceding vehicle20cannot be acquired, i.e. the location T1. Furthermore, the vehicle10presumes the presuming travel trajectory35for locations further from the location22, based on the relationship between the travel trajectory31of the entering vehicle30from the location T0to the location T1, and the travel trajectory21of the preceding vehicle20. Furthermore, the vehicle10calculates the shortest distance between the presuming travel trajectory35and the travel trajectory31of the entering vehicle30, which is the deviation, as the “presuming deviation amount H2” at any time, and detects the position where the “presuming deviation amount H2” becomes within the “determination value Δh”. Furthermore, the vehicle10switches the target travel trajectory of the travel trajectory assistance from the travel trajectory21of the preceding vehicle20to the travel trajectory31of the entering vehicle30at the detected position.

Next, the configuration of this embodiment is described. Same with the first embodiment, it is determined whether the preceding vehicle following assistance can be performed by taking the vehicle10is travelling etc. as conditions. Therefore, the details of the process corresponding to the process of generating the target ravel trajectory in the first embodiment (Step S2) are described as follows.

As shown byFIGS. 10A, 10BandFIG. 11, if the process of generating the target travel trajectory is started, the driving assistance device300determines whether a preceding vehicle20is present (Step S10). When it is determined that the preceding vehicle20is absent (NO in Step S10), the driving assistance device300clears the target travel trajectory (Step S11), and ends the target process of generating the target travel trajectory.

On the other hand, when it is determined that the preceding vehicle20is present (YES in Step S10), the driving assistance device300determines whether it is during the setting of the target travel trajectory (Step S12). Whether or not it is during the setting of the target travel trajectory is determined by setting (not clearing) the target travel trajectory. When it is determined that it is not during the setting of the target travel trajectory (NO in Step S12), the driving assistance device300determines whether the travel trajectory21of the preceding vehicle20is present, according to the travel position of the vehicle10(Step S13). When it is determined that the travel trajectory21of the preceding vehicle20is absent according to the travel position of the vehicle10(NO in Step S10), the driving assistance device300clears the travel trajectory (Step S11), and ends the process of generating the target travel trajectory. On the other hand, when it is determined that the travel trajectory21of the preceding vehicle20is present according to the travel position of the vehicle10(YES in Step S13), the driving assistance device300sets the travel trajectory21of the preceding vehicle20as the target travel trajectory (Step S14) and ends the process of generating the target travel trajectory.

Moreover, when it is determined as during the setting of the target travel trajectory (YES in Step S12), the driving assistance device300determines whether or not the adjustment object vehicle of the speed assistance portion330has been switched to the other vehicle (Step S15).

Then, when it is determined that the adjustment object vehicle of the speed assistance portion330is not changed to the other vehicle (NO in Step S15), the driving assistance device300determines whether it is during the determining of the “deviation” (Step S26). The determining of the “deviation amount” is determined by setting a flag of during the determining of the “deviation amount”, such as setting the flag to “1”. When it is determined that it is not during the determining of the “deviation amount” (NO in Step S26), the driving assistance device300sets the target travel trajectory based on the travel trajectory21of the preceding vehicle20(Step S27), and ends the process of generating the target travel trajectory. On the other hand, when it is determined that it is during the determining of the “deviation amount” (YES in Step S26), the driving assistance device300proceeds the process to Step S18as described in the following.

Furthermore, when it is determined that the adjustment object vehicle of the speed assistance portion330is changed to other vehicle (YES in Step S15), the driving assistance device300determines whether the adjustment object vehicle of the speed assistance portion330is switched from the preceding vehicle20to the entering vehicle30(Step S16).

When it is determined that the adjustment object vehicle of the speed assistance portion330is not changed from the preceding vehicle20to the entering vehicle30(NO in Step S16); the driving assistance device300clears the target travel trajectory (Step S25), and ends the process of generating the target travel trajectory. Such a circumstance is that the other vehicle other than the entering vehicle30becomes the preceding vehicle20, because the vehicle10changes its lane, etc.

On the other end, when it is determined that the adjustment object vehicle of the speed assistance portion330is changed from the preceding vehicle20to the entering vehicle30(YES in Step S16), the driving assistance device300sets a flag of during the determining of the “deviation amount” (Step S17). Then, the driving assistance device300calculates the “initial deviation amount H0” of the target travel trajectory11and the travel trajectory31of the entering vehicle30(Step S30), and resets the values of the two kept travel distances (Step S31). For example, the values of the two travel distances D1dand D2drelating to the entering vehicle30used when calculating the presuming travel trajectory35(by reference toFIGS. 16 and 17) are set to “0”.

Then, when it is determined that the travel trajectory21of the preceding vehicle20is acquired (YES in Step S18), the driving assistance device300sets the target travel trajectory based on the travel trajectory21of the preceding vehicle20(Step S19), and proceeds the process to Step S20, as described in the following. On the other hand, when it is determined that the travel trajectory21of the preceding vehicle20before the entering of the entering vehicle30is not acquired (YES in Step S18), the driving assistance device300proceeds the process to Step S20, as described in the following.

Then, when it is determined that the “deviation amount” between the travel trajectory21of the preceding vehicle20and the travel trajectory31of the entering vehicle30can be calculated (YES in Step S20), the driving assistance device300calculates the “deviation amount” between the travel trajectory21of the preceding vehicle20and the travel trajectory31of the entering vehicle30(Step S22). Moreover, the driving assistance device300updates the value of the travel distance D1dof the entering vehicle30(Step S32), and substitutes the calculated “deviation amount” to the presumed “presuming deviation amount H2” (Step S34). Then, the process proceeds to the Step S38described as follows.

Moreover, description is made with reference toFIG. 19, when it is determined that the “deviation amount” between the travel trajectory21of the preceding vehicle20and the travel trajectory31of the entering vehicle30cannot be calculated (NO in Step S20), the driving assistance device300updates the value of the travel distance D2dof the entering vehicle30(Step S35). As described in the following, using the updates, the position34of the presuming travel trajectory35corresponding to the position of the travel distance D2dof the entering vehicle30is determined.

Furthermore, the driving assistance device300calculates the “presuming deviation amount H2” between the position34on the travel trajectory31of the entering vehicle30corresponding to the travel distance D2dof the entering vehicle30, and a position on the presuming travel trajectory35corresponding to that position (Step S36). Moreover, the driving assistance device300sets the trajectory from the location22of the travel trajectory21of the preceding vehicle20to the position24of the presuming travel trajectory35, as the target travel trajectory11(Step S37). Then, the process proceeds to the Step S38described as follows.

The driving assistance device300determines whether the “presuming deviation amount H2” is the “determination value Δh” or below (Step S38). When it is determined that the “presuming deviation amount H2” is not the “determination value Δh” or below (NO in Step S38), the driving assistance device300ends the process of generating the target travel trajectory. On the other hand, when it is determined that the “presuming deviation amount H2” is the “determination value Δh” or below (YES in Step S38), the driving assistance device300unsets the flag of determining the “deviation amount”, and ends the process of generating the target travel trajectory.

Furthermore, by repeatedly performing the process of generating the target travel trajectory, the travel trajectory21of the preceding vehicle20is set as the target travel trajectory, or the presuming travel trajectory35is set, or the travel trajectory31of the entering vehicle30is set as the target travel trajectory based on the event that the “presuming deviation amount H2” becomes the “determination value Δh” or below.

Next, by reference toFIGS. 12-18, the calculation of the presuming travel trajectory is described. Firstly, by reference toFIGS. 12-15, the state change of the travel trajectory assistance of the vehicle10is described.

As illustrated inFIG. 12, the vehicle10travelling on the lane R2performs preceding vehicle following assistance with respect to the preceding vehicle20travels in the front in the travel direction of the vehicle10. In addition, in the adjacent lane, the entering vehicle30is travelling in the same direction with the travel direction of the vehicle10. The vehicle10acquires the travel trajectory31of the entering vehicle30, as the entering candidate vehicles.

As illustrated inFIG. 13, based on the event that the other vehicle (entering vehicle30) enters the travelling lane R2, the vehicle10detects the other vehicle as the entering vehicle30that enters between the vehicle10and the preceding vehicle20; and, in the inter-vehicle distance assistance, the adjustment object vehicle is changed from the preceding vehicle20to the entering vehicle30.

On the other hand, as illustrated inFIG. 14, when detecting the entering vehicle30, the vehicle10determines the location T0where the entering vehicle30enters the lane R2, and determines the position in the target travel trajectory11that corresponds to the location T0. Herein, the position that corresponds to the location T0can be set as the shortest distance to the target travel trajectory11, which is length of a vertical line from the location T0to the target travel trajectory, i.e., the line vertical to the target travel trajectory11. In addition, the position of the preceding vehicle20is the location22where the travel trajectory21of the preceding vehicle20cannot be acquired, and a distance D1from the position that corresponds to the location T0to the location22in the target travel trajectory11can be calculated.

That is, as illustrated inFIG. 15, in the vehicle10, the travel trajectory assistance is performed for each of the following areas: a first area Z1where the target travel trajectory11sets the ravel trajectory21of the preceding vehicle20; a third area Z3where the target travel trajectory11sets the travel trajectory31of the entering vehicle30; and a second area Z2where the target ravel trajectory sets the presuming travel trajectory35.

Firstly, in the first area Z1, the “initial deviation amount H0” at the location T0, the “deviation amount H1” at the location T1, a length “D1” of the target travel trajectory11from the location T0to the location T1, and a length D1dof the travel trajectory31of the entering vehicle30are obtained (by reference toFIG. 16). The “initial deviation H0” at the location T0and the “deviation amount H1” at the location T1are, at each of the locations T0and T1, the lengths in the vertical line vertical to the target travel trajectory11from the target travel trajectory11to the travel trajectory31of the entering vehicle30.

Next, in the second area Z2, the location T3(positions23,33) where the presuming travel trajectory35intersects with the travel trajectory31, of the entering vehicle30, and a length “D3” of the presuming travel trajectory35from the location T0to the location T3, and a length “D3d” of the travel trajectory31of the entering vehicle30are obtained (by reference toFIG. 16). In addition, the length from the travel trajectory35to the travel trajectory31of the entering vehicle30at the points between the location T1and the location T3, in the perpendicular line perpendicular to the presuming travel trajectory35, i.e., the “presuming deviation amount H2”, and a length “D2” of the presuming travel trajectory35from the location T0at this time are obtained.

Furthermore, in the third area Z3, the travel trajectory31of the entering vehicle30is set as the target travel trajectory. Next, the calculation of the presuming travel trajectory is described in details by reference toFIGS. 16-18.

Firstly, as illustrated inFIG. 16, the “initial deviation amount H0” at the location T0, the “deviation amount H1” at the location T1, the length “D1d” of travel trajectory31of the entering vehicle30from the location T0to location T1, and the length “D3d” of the travel trajectory31of the entering vehicle30from the location T0to the location T3are obtained from the states of the vehicle10and the entering vehicle30of theFIG. 16. At this time, as a first relational expression containing gradual change ratio, can use the expression (1) described below, and the gradual change ratio is the ratio of the travel trajectory31of the entering vehicle30approaching the travel trajectory21of the preceding vehicle20.
D3d:(D3d−D1d)=H0:H1   (1)

In addition, as illustrated inFIG. 17, the “initial deviation amount H0” at the location T0, the “deviation amount H2” at the location T2, the length “D2d” of travel trajectory31from the location T0to the location T1, and the length “D3d” of the travel trajectory31of the entering vehicle30from the location T0to the location T3are obtained from the states of the vehicle10and the entering vehicle30of theFIG. 17. At this time, as a second relational expression containing the same gradual change ratio, the expression (2) described below can be used.
D3d:(D3d−D2d)=H0:H2   (2)

Incidentally, since if the presuming travel trajectory35is not calculated to the location T3, the D3dcannot be used; therefore, as an expression eliminated with the D3dwhich cannot be calculated at the location T2, the following expression (3) can be obtained from the above expression (1) and (2).
H2=H0−D2d·(H0−H1)/D1d(3)

That is, based on the expression (3), the vehicle10can presume the position where it is away from the travelling position of the entering vehicle30by the “presuming deviation amount H2”, as a position on the presuming travel trajectory35.

Since the “presuming deviation amount H2” contains a travel trajectory similar ratio acquired as the ratio that the travel trajectory31of the entering vehicle30approaches the travel trajectory acquired as the travel trajectory21of the preceding vehicle20, thus, the presuming travel trajectory can be obtained based on the obtained similar ratio and the travel trajectory31of the entering vehicle30.

In addition, according to the “presuming deviation amount H2”, the distance between the location T0of the travel trajectory21of the preceding vehicle20and the travel trajectory31of the entering vehicle30is obtained as the inter-trajectory distance (initial deviation amount H0), and the calculated inter-trajectory distance (initial deviation amount H0) is decreased based on the similar ratio of the travel trajectory31of the entering vehicle30(calculates H2), thus, the presuming travel trajectory can be calculated.

As illustrated inFIG. 18, in the creating process of the target travel trajectory, in the second area Z2, a process of creating the presuming travel trajectory35is performed. In the process of creating the presuming travel trajectory35, firstly, after setting the target travel trajectory11to the location22, at the position32of the travel trajectory31of the entering vehicle30corresponding to the location22(location T1), the “presuming deviation amount H2” is calculated based on expression (3). Furthermore, a circle32R with a radius of the “presuming deviation amount H2” with a center on the position32is presumed, and the trajectory extends from the location22of the target travel trajectory11in a manner of closing to a straight line as much as possible and tangent to the periphery of the circle32R is presumed. In addition, at the location T1, the “presuming deviation amount H2” is the same value with the “deviation amount H1”.

Then, such a creating process of the target travel trajectory is periodically repeated based on the travel trajectory31of the entering vehicle30moves forward. That is, in the creating process of the target travel trajectory, the position34of the travel trajectory31of the entering vehicle30is set as the location T2, and the “presuming deviation amount H2” is calculated based on expression (3). Furthermore, the circle34R with a radius of the “presuming deviation amount H2” with a center on the position34is presumed, and the trajectory that extends from the location22of the target travel trajectory11in a manner of closing to a straight line and tangent to the periphery of the circle34R is presumed. Therefore, the presuming travel trajectory35is set to the position24corresponding to the location T2.

Therefore, the presuming travel trajectory35is set as passing the end position (location22) of the target travel trajectory11, and tangent to the circle that has a radius of “presuming deviation amount H2” from the point of the travel trajectory31of the entering vehicle30.

In addition, in the process of creating the target travel trajectory, it is also determined whether the calculated “presuming deviation amount H2” is within the “determination value Δh”. Furthermore, when it is determined that the “presuming deviation amount H2” is within the “determination value Δh”, since the travel trajectory31of the entering vehicle30is set as the target travel trajectory, thus the process of creating the presuming travel trajectory35is ended.

Therefore, a driving assistance device can be provided in which the restraining of the uncomfortable feeling of the user can be suitably achieved even if the entering vehicle30enters between the vehicle10and the preceding vehicle20.

As described above, according to the driving assistance device of this embodiment, other than the effects (1)-(4) described in the first embodiment, the following effect can also be obtained.

(5) Even when the travel trajectory21of the preceding vehicle20cannot be acquired, the steering control is performed to follow the presuming travel trajectory35of the preceding vehicle20, until the location; where the deviation amount (presuming deviation amount H2) between the presuming travel trajectory35of the preceding vehicle20and the travel trajectory31of the entering vehicle30becomes the predetermined determination value Δh or below, thus, the movement of the host vehicle with respect to the deviation amount between the presuming travel trajectory35of the preceding vehicle20and the travel trajectory31of the entering vehicle30can be restrained (the unsteadiness is reduced).

(6) Even when the travel trajectory21of the receding vehicle20cannot be acquired, the presuming travel trajectory35presumed as the travel trajectory21of the preceding vehicle20from the travel trajectory31of the entering vehicle30is used, thus, the presuming deviation amount H2with respect to the travel trajectory31of the entering vehicle30is calculated, the location where the deviation amount becomes with the predetermined determination value Δh or below can be determined.

(7) Since the presuming travel trajectory of the preceding vehicle20is presumed based on the similar ratio of the entering vehicle30; therefore, the presumed presuming travel trajectory35has high continuity with respect to the travel trajectory31of the entering vehicle30.

The Third Embodiment

By reference toFIG. 19, the third embodiment which embodies the driving assistance device is described. In this embodiment, the configuration of changing the travel position of the vehicle10and acquire the travel trajectory21of the preceding vehicle20for a long-term, this is different from the configuration of acquiring the travel trajectory21of the preceding vehicle20in the first embodiment, but the other configurations are the same. Therefore, the different configuration from the first embodiment is described as follows; and as for the same configuration with the first embodiment, same reference numerals are used; and in order to make it convenient for describing, the detailed descriptions are omitted.

Incidentally, in order to calculate the “deviation amount H1”, the travel trajectory21of the preceding vehicle20and the travel trajectory31of the entering vehicle30are necessary. However, if the entering vehicle30enters between the vehicle10and preceding vehicle20, the preceding vehicle20cannot be shot from the vehicle10, or cannot be measured by the radar; thus, the travel trajectory21of the preceding vehicle20cannot be acquired.

Therefore, in this embodiment, even if the entering vehicle30enters between the vehicle10and the preceding vehicle20, the time period that is capable of acquiring the travel trajectory21of the preceding vehicle20can be guaranteed as long as possible. That is, the steer assistance portion380of the vehicle10performs an assistance to assist the vehicle10to move towards a width direction of the lane R3that is opposite to the entering direction of the entering vehicle30, when it is determined that it is difficult to acquire the travel trajectory of the preceding vehicle20due to the effect of the entering vehicle30. The steer assistance portion380performs the determination that it is difficult to acquire the travel trajectory21of the preceding vehicle20due to the effect of the entering vehicle30, based on the event that the entering vehicle30enters the width occupied by the travelling vehicle10in a direction perpendicular to the travel direction of the vehicle10. For example, as the event that the entering vehicle30enters the width occupied by the travelling vehicle10, the entering vehicle detection portion320detecting the entering vehicle30; the interval between the width occupied by the vehicle body width of the vehicle10when travelling and the entering vehicle30; and in the image data, the vehicle body of the entering vehicle30overlapping with a part of the vehicle body of the preceding vehicle20etc. may be used.

As illustrated inFIG. 19, in the lane R3, the vehicle10performs travel trajectory assistance to the target travel trajectory11which is set based on the travel trajectory21of the preceding vehicle20. If the vehicle10detects the entering vehicle30, the position where the target travel trajectory11moves in the direction opposite to the entering direction of the entering vehicle30by an offset value Hf is used as the presuming travel trajectory11ato set the target travel trajectory. Therefore, the vehicle10performs travel trajectory assistance to the presuming travel trajectory11a.In addition, the target travel trajectory11is set as moving slowly from the travel trajectory21of the preceding vehicle20to the presuming travel trajectory11a.In addition, the offset value Hf is a preset value, which keeps the vehicle10within the travelling lane R3. In addition, the offset value Hf is set as a distance of the perpendicular direction to the target travel trajectory11.

Furthermore, the vehicle10changes the setting of the target travel trajectory11from the presuming travel trajectory11ato the acquired travel trajectory21of the preceding vehicle20, based on the event that the travel trajectory21of the preceding vehicle20cannot be acquired. The target travel trajectory11is set as moving slowly from the presuming travel trajectory11ato the travel trajectory21of the preceding vehicle20. That is, the target travel trajectory11returns to the target travel trajectory11before changing to the presuming travel trajectory11a.Therefore, the assistance that assists the vehicle10to move to a lane width direction opposite to the entering direction of the entering vehicle30is ended.

Therefore, after the position where the travel trajectory21of the preceding vehicle20cannot be acquired, the area that has to be travelled on based on the presuming travel trajectory can be eliminated or shortened. In addition, since the vehicle10travels by avoiding the entering vehicle30, thus, the travel satisfies the feeling of the users and brings peace to the user. Moreover, the user can acknowledge that the following travelling assistance is performing.

As described above, according to the driving assistance device of this embodiment, other than the effects (1)-(4) described in the first embodiment, the following effect can also be obtained.

(8) Since it is capable of delaying the timing when the vehicle10overlaps with the entering vehicle30in a range necessary for detecting the preceding vehicle20, or reducing the overlapping; therefore, even with the entering of the entering vehicle30, the travel trajectory21of the preceding vehicle20can be acquired as long as possible. Specifically, when the entering vehicle30is a large vehicle, there is a high possibility that the vehicle10cannot acquire the travel trajectory of the preceding vehicle20; however, the vehicle10can acquire the travel trajectory21of the preceding vehicle longer than usual.

(9) By presuming the presuming travel trajectory11awhen the entering vehicle30enters the width occupied by the vehicle10, the vehicle10can be moved with allowance; therefore, the unconformable feeling of the user brought by the assistance of acquiring the trajectory of the preceding vehicle20is small.

(10) A driving assistance is provided in which when it is not necessary to use the travel trajectory21of the preceding vehicle20for the target travel trajectory11of the vehicle10, the travel route of the vehicle10returns to the target travel trajectory11, and the uncomfortable feeling of the user is small.

The Fourth Embodiment

By reference toFIGS. 20 and 21, the fourth embodiment which embodies the driving assistance device is described.

In this embodiment, the configuration is that the presuming travel trajectory is calculated based on the information of the adjacent vehicle40etc., this is different from the configuration in the second embodiment, but the other configurations are the same. Therefore, the different configuration from the second embodiment is described as follows; and as for the same configuration with the first embodiment, same reference numerals are used; and in order to make it convenient for describing, the detailed descriptions are omitted.

In this embodiment, when the travel trajectory21of the preceding vehicle20cannot be acquired due to the entering of the entering vehicle30, the presuming travel trajectory is created based on the travel trajectory41of the adjacent vehicle40. Therefore, based on the travel trajectory41of the adjacent vehicle40which travels in the lane R41adjacent to the lane R40on which the vehicle10travels, the presuming travel trajectory is obtained.

As illustrated inFIG. 20, in the lane R4, the vehicle10performs travel trajectory assistance to the target travel trajectory11set based on the travel trajectory21of the preceding vehicle20. However, as illustrated inFIG. 21, if the entering vehicle30enters between the vehicle10and the preceding vehicle20, the preceding vehicle20cannot be shot from the vehicle10, or cannot be measured by the radar; thus, the travel trajectory21of the preceding vehicle20further from location22cannot be acquired.

Therefore, the presuming travel trajectory is calculated based on the travel trajectory41of the adjacent vehicle40, and the calculated presuming travel trajectory is set as the target travel trajectory. Firstly, the area K1in the acquired travel trajectory41of the adjacent vehicle40and further from the location22in the travel trajectory21of the preceding vehicle20is determined.

Furthermore, when it is determined that the area K1is a straight line area, the travel trajectory41of the adjacent vehicle40is moved in parallel, thus, it is set as the presuming travel trajectory. Therefore, further from the location22in the travel trajectory21of the preceding vehicle20, the target travel trajectory is also set based on the presuming travel trajectory.

In addition, when it is determined that the area K1is a curve area, based on the difference between the radius of the travel trajectory41of the adjacent vehicle40corresponding to area K1, and the radius of the lane R40on which the vehicle10travels, the travel trajectory41of the adjacent vehicle40that travels on the lane R41is corrected to become the travel trajectory of the lane R40. For example, when the radius of the lane R41corresponding to area K1is measured as Ra, and the lane interval between the lane R41and the lane R40is B0, the radius Rb of the lane R40on which the vehicle10travels is obtained based on Ra+B0. Furthermore, based on the radius Ra of the lane R41and the radius Rb of the lane R40, the travel trajectory41(trajectory41a) of the adjacent vehicle40corresponding to area K1is corrected, thus, the corrected travel trajectory becomes the presuming travel trajectory (presuming trajectory41b) and is set as the target travel trajectory further from the location22of the ravel trajectory21of the preceding vehicle20.

As described above, according to the driving assistance device of this embodiment, other than the effects (1)-(4) described in the first embodiment, the following effect can also be obtained.

(11) The presuming travel trajectory can be presumed by using the travel trajectory41of the preceding adjacent vehicle40. In addition, the presuming travel trajectory can be presumed by using the road information such as the lanes, guard rail and side walls. At this time, the presuming travel trajectory is presumed by using a plurality of information, thus, the presuming accuracy can be improved.

Other Embodiments

In addition, the above embodiments can also be carried out by the following aspects.

In the above embodiment, a case is described in which the travel trajectory assistance is performed based on the target travel trajectory. At this time, if the signal of the steer amount for following the target travel trajectory from the steer assistance portion is displayed on the display device, the vehicle travels to follow the target travel trajectory by using the operations of the user. In addition, if the signal of the steer amount for following the target travel trajectory from the steer assistance portion is input to the acceleration control device, then the vehicle travels to automatically steer within a permitted range and follow the target travel trajectory.

The above first to fourth embodiments can be carried out by combining more than any two of the embodiments. In the above embodiment, a case is described in which the vehicle-mounted network is CAN. However, it is not limited to this, as long as the vehicle-mounted network can communicatively connect the connected ECU, the vehicle-mounted network can also be consisted of networks such as Ethernet (registered trademark), FlexRay (registered trademark), and IEEE1394 (FireWire (registered trademark)) etc. In addition, the vehicle-mounted network can also be configured by combining these networks, including CAN. Therefore, for the vehicle using the driving assistance device, the improvement of the freedom of the configuration can be achieved.

In the above embodiment, a case is described in which the vehicle-mounted control device200is consisted of one ECU. However, it is not limited to this; the vehicle-mounted control device can also realize its function by using the cooperating action of a plurality of ECUs. For example, the vehicle-mounted control device can also be consisted using the driving system, travelling system, vehicle body system, or information device system, etc. as the'plurality of ECUs as the control object. Therefore, the improvement of the freedom of the design of the driving assistance device can be achieved.

In the above embodiment, a case is described in which the navigation system112, the display device113, and the vehicle-mounted control device200, etc. are integrally provided on the vehicle10. However, it is not limited to this, as long as the navigation system, the display device, and the vehicle-mounted network can be communicatively connected, portable information process devices such as a mobile phone or a smart phone, etc. can be used for all of or a part of the above function. Therefore, the improvement of the freedom of the design of the driving assistance device can be achieved.

In the above third embodiment, a case is described in which the assistance that assists the host vehicle to move to a lane width direction opposite to the entering direction of the entering vehicle is ended when the travel trajectory21of the preceding vehicle20cannot be acquired and returning to the target travel trajectory11. However, it is not limited to this, since the travel trajectory of the preceding vehicle is acquired, the object of the travel trajectory assistance may return to the target travel trajectory until the position where it is assumed that the travel trajectory of the preceding vehicle intersects with the travel trajectory of the entering vehicle. In addition, the assistance that assists the host vehicle to move to a lane width direction opposite to the entering direction of the entering vehicle may also be ended when the location determination portion determined that the deviation amount becomes the predetermined value or below.

Therefore, the travel distance caused by the target travel trajectory based on the offset value can be shortened. In the above third embodiment, a case is described in which the entering vehicle30enters the width occupied by the vehicle10is determined based on the event that the entering vehicle30enters the lane R3. However, it is not limited to this, it may also be determined that the entering vehicle enters the width occupied by the entering vehicle, based on the position where the travel trajectory of the preceding vehicle is difficult to be acquired by the host vehicle determined based on the width and height etc. of the entering vehicle. Therefore, the improvement of the convenience of the driving assistance device can be achieved.

In the above third embodiment, a case is described in which the offset value Hf is predetermined. However, it is not limited to this, the offset value Hf may also change according to the distance to the entering vehicle, and the speed of the vehicle, etc. For example, when the distance from the vehicle to the entering vehicle is short or the vehicle speed is high, the offset value may be large. Therefore, since the assistance that is capable of reducing the uncomfortable feeling of the users can be performed, the expansion of the application possibility of the driving assistance device can be achieved.

In the above fourth embodiment, a case is described in which the target travel trajectory is set according to the travel trajectory41of the adjacent vehicle40. However, it is not limited to this; the target travel trajectory may also be set based on the area defined by the lanes of the road where the vehicle can travel, in which the area is a travel route. That is, the presuming travel trajectory may also be obtained based on at least one of the travel trajectory of the adjacent vehicle travelling in the lane adjacent to the lane where the vehicle travels, and the shape (straightness or curvature) of the travel route on which the vehicle travels. Moreover, in the above description, a case is illustrated in which the travel route is the lane of the road, but this can be replaced, for example, the travel route may be the area defined by the road facilities such as the lanes of the road, guard rails and side walls, etc., where the vehicle can travel. Therefore, the expansion of the situation under which the driving assistance device can be used is achieved.

In addition, the presuming travel trajectory can be obtained respectively based on the adjacent vehicle, lanes on the road, guard rails and side walls, and the deviation of them is used for reliability assessment evaluation, and the obtained presuming travel trajectory is not used for the driving assistance device when the deviation is large. Therefore, the maintenance of the accuracy of the driving assistance is achieved.

In the above embodiment, a case is described in which the setting of the presuming travel trajectory is changed from the travel trajectory21of the preceding vehicle20to the travel trajectory31of the entering vehicle30, regardless of the deviation or angle between the travel trajectory21of the preceding vehicle20and the travel trajectory31of the entering vehicle30. However, it is not limited to this; the travel trajectory of the preceding vehicle and the travel trajectory of the entering vehicle can also overlap such that these 2 trajectories are tangent with each other (the advancing azimuth angles are connected continuously). In addition, when there is an angle formed by the travel trajectory of the preceding vehicle and the travel trajectory of the entering vehicle, the cross section of these 2 travel trajectories may also connect in a curved way. Therefore, the uncomfortable feeling of the user brought by the driving assistance device can be further restrained.

In the second embodiment as above, a case that the travel trajectory31of the entering vehicle30is linearly approaching the travel trajectory21of the preceding vehicle20is described. However, it is not limited to this; the presuming travel trajectory may also be created based on the approaching ratio when the travel trajectory of the entering vehicle approaches the travel trajectory of the preceding vehicle in a manner of describing a sine wave. Therefore, the target travel trajectory can be created with a higher accuracy.

In the second embodiment as above, a case that the gradually changed ratio is constant is described. However, it is not limited to this, the gradually changed ratio may also be changed based on the trajectory until the travel trajectory of the preceding vehicle and the travel trajectory of the entering vehicle overlap, the inter-vehicle distance between the preceding vehicle and the entering vehicle, and the vehicle speeds of the preceding vehicle and the entering vehicle, etc. For example, the gradually changed ratio may be reduced when the inter-vehicle distance with respect to the preceding vehicle is large or the vehicle speed is high, so as to make the overlapping of the two travel trajectories smooth. Therefore, the uncomfortable feeling of the user can be further restrained.

In the above embodiment, a case is described in which the target trajectory setting portion370sets the target travel trajectory based on the travel trajectory21of the preceding vehicle20, the travel trajectory31of the entering vehicle30, or the presuming travel trajectory. However, it is not limited to this; the target travel trajectory on which the host vehicle should travel may also be set based on the preceding vehicle, the travel trajectory of the surrounding vehicle, and the road shape, etc. Therefore, the assistance accuracy of the driving assistance device can also be improved.

In the above embodiment, a case is described in which the “determination value Δh” is set as a parameter. However, it is not limited to this; the determination value may also be variable by calculating according to the vehicle speed, or referring to the tables. Therefore, the uncomfortable feelings of the user can be further restrained.

In the above embodiments, a case is described in which the preceding vehicle detection portion310, the entering vehicle detection portion320, the speed assistance portion330, the preceding vehicle travel trajectory acquisition portion340, the entering vehicle travel trajectory acquisition portion350, the location determination portion360, the target trajectory setting portion370and the steer assistance portion380are independently provided. However, it is not limited to this, the preceding vehicle detection portion, the entering vehicle detection portion, the speed assistance portion, the preceding vehicle travel trajectory acquisition portion, the entering vehicle travel trajectory acquisition portion, the location determination portion, the target trajectory setting portion and the steer assistance portion may also be provided by combining all of or a part of their functions, and may also be provided by sharing a part of their functions. For example, all of or a part of the preceding vehicle detection portion, the entering vehicle detection portion and the speed assistance portion may be combined, as the speed assistance portion (speed control portion) and the inter-vehicle distance assistance portion (inter-vehicle distance control portion). In addition, all of or a part of the preceding vehicle travel trajectory acquisition portion, the entering vehicle travel trajectory acquisition portion, the location determination portion, the target trajectory setting portion and the steer assistance portion may be combined, as the target trajectory setting portion and the travel trajectory assistance portion (travel trajectory control portion). Therefore, the improvement of the freedom of the configuration of the driving assistance device is achieved.