DRIVING SUPPORT SYSTEM
A driving support system includes a lane detecting unit for detecting lanes around a vehicle, a route correcting unit for correcting a route along which the vehicle is expected to travel taking into consideration an obstacle on the route after the route has been recognized by lanes detected by the lane detecting unit, and a control unit for controlling the vehicle on the basis of the positional relation between the corrected route determined by the route correcting unit and the vehicle.
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1. Field of the Invention
The present invention relates to a driving support system for supporting driving operations for making a vehicle travel along a proper route on a road.
2. Description of the Related Art
A technique disclosed in JP-A-2005-324782 applies a yawing moment to a vehicle when the vehicle tends to deviate from a desired lane by controlling braking forces acting on the wheels of the vehicle to prevent the vehicle from deviating from a desired lane and to notify the driver that there is the possibility that the vehicle deviates from the lane. The technique changes the value of controlled variable, such as a threshold for off-lane avoidance control, taking into consideration obstacles beside the lane to achieve optimum off-lane avoidance control.
Patent Document 1: JP-A-2005-324782
Nothing is mentioned in JP-A-2005-324782 about simultaneously carrying out supporting operations for guiding the vehicle to a desired route and for avoiding obstacles. For example, when there is an obstacle on a lane to which the vehicle is to be guided, the technique disclosed in JP-A-2005-324782 executes an obstacle avoidance operation after the vehicle has completed changing the lanes. Therefore, it is possible that the start of the obstacle avoidance operation cannot be properly timed. Only either of the threshold for off-lane avoidance control and the threshold for obstacle avoidance control is used for driving support control at some point of time and at some position. Therefore, it is possible that driving support control is not executed for avoiding an obstacle after the vehicle has deviated from the lane when the obstacle is outside the threshold for deviation avoidance control. When the driving support control is executed on the basis of the threshold for obstacle avoidance control, there is the possibility that sharp driving support control is executed to avoid an obstacle because the threshold for ordinary off-lane avoidance control is ineffective. Such a mode of driving support control gives the driver a feeling of discomfort. Thus, the technique disclosed in JP-A-2005-324782 cannot make driving support for guiding the vehicle along a desired route and driving control for avoiding obstacles compatible.
SUMMARY OF THE INVENTION.Accordingly, it is an object of the present invention to provide a driving support system capable of making driving support control for guiding a vehicle along a route and driving support control for avoiding obstacles compatible and of scarcely giving a feeling of discomfort to the driver.
A driving support system in one aspect of the present invention includes: a lane detecting unit for detecting lanes around a vehicle; a route correcting unit for correcting a route along which the vehicle is expected to travel taking into consideration an obstacle on the route after the route has been recognized by lanes detected by the lane detecting unit; and a control unit for controlling the vehicle on the basis of the positional relation between the corrected route determined by the route correcting unit and the vehicle.
The present invention provides the safe driving support system capable of making driving support control for guiding the vehicle along the route and driving support control for avoiding obstacles compatible and of scarcely giving a feeling of discomfort to the driver.
The above and other objects, features and advantages of the present invention will become more apparent from the following description taken in connection with the accompanying drawings, in which:
Preferred embodiments of the present invention will be described with reference to the accompanying drawings.
The vehicle is provided with a manipulated variable measuring unit for measuring values of manipulated variables altered by the driver, including a steering angle measuring device 2, a turn signal control lever 3, an accelerator pedal position measuring device 4, a brake pedal position measuring device 5, and a controller 1. Signals representing values of operated variables altered by the driver and provided by the steering angle measuring device 2, the turn signal control lever 3, the accelerator pedal position measuring device 4, and the brake pedal position measuring device 5 are sent to the controller 1. The driver's intention to change the route can be known from a signal provided by a turn signal controller 3 when the turn signal control lever is operated.
The controller 1 is connected to a navigation system 6 to receive signals from the navigation system 6. Those signals represent a set route, map data, the position of the vehicle on a map, the direction of the vehicle, lane information, such as the number of lanes, speed limit, types of roads, i.e., highways and general motorways, and branch roads. Basically, the route is set by the driver. The navigation system 6 may set or change a route automatically on the basis of past data on traveling routes and traffic information.
The vehicle is provided with an operation parameter measuring unit for measuring values of parameters indicating the operating condition of the vehicle, including wheel speed measuring devices 7fL, 7fR, 7rL and 7rR, and vehicle behavior measuring device 8. Signals provided by those devices are sent to the controller 1. The vehicle behavior measuring device measures longitudinal acceleration, lateral acceleration and yaw rate.
The vehicle is provided with environmental condition measuring devices for measuring conditions of the environment around the vehicle, including a front camera 10f, a front radar 11f, a rear camera 10r, a rear radar 11r, a left front camera 12L, a right front camera 12R, a left rear camera 13L and a right rear camera 13R. Those environmental condition measuring devices send information about lane markings and obstacles around the vehicle to the controller 1.
The front camera 10f is provided with an image pickup unit for obtaining an image of a scenery around the vehicle, a lane identifying unit for identifying lanes on the basis of lane markings or road boundaries shown in an image obtained by the image pickup unit, and an output unit that provides signals representing the positional relation between the vehicle and objects of recognition, such as obstacles including other vehicles and pedestrians, types of lane markings, and types of road boundaries. The lane markings are marks indicating running areas according to traffic rules, including lines, cat's eyes, botts' dots, colors of lines, and types of lines, such as continuous lines, broken lines, dotted lines and shaded lines. Road boundaries include edges of road shoulders, side ditches, curbs, embankments, guard rails and walls. The lane markings indicate boundaries between areas for vehicles and those not for vehicles.
The front radar 11f detects and locates other vehicles and pedestrians and provides signals representing positional relation between the vehicle and those objects. The front radar 11f can detect remote obstacles more accurately than the front camera 10f. The front camera 10f has a detection field angle greater than that of the front radar 11f and can recognize the type of obstacles.
The rear camera 10r, the left front camera 12L, the right front camera 12R, the left rear camera 13L and the right rear camera 13R are similar in functions, advantages and disadvantages to the front camera 10f, and the front radar 11f and the rear radar 11r are similar in functions, advantages and disadvantages.
The vehicle is provided with an engine 21, an electronically controlled brake system 22, an electronically controlled differential mechanism 23, and an electronically controlled steering system 24. The controller 1 gives drive signals to actuators included in those systems 22, 23 and 24 on the basis of values of manipulated variables given by the driver and environmental conditions. When the vehicle needs to be accelerated, the controller 1 gives an acceleration signal to the engine 21. When the vehicle needs to be decelerated, the controller gives a deceleration signal to the electronically controlled brake system 22. When the vehicle needs to be turned, the controller 1 gives a turn signal to at least one of the electronically controlled brake system 22, the electronically controlled differential mechanism 23 and the electronically controlled steering system 24.
The electronically controlled brake system 22 is a hydraulic brake system capable of controlling individual braking forces respectively applied to the wheels. The electronically controlled brake system applies braking forces to either the right wheels or the left wheels in response to a turning request to apply a yawing moment to the vehicle.
The electronically controlled differential mechanism 23 drives an electric motor or a clutch to generate a torque difference between the right and the left axle in response to a turning request to apply a yawing moment to the vehicle.
The electronically controlled steering system 24 is, for example, a steer-by-wire steering system capable of correcting the steering angle independently of the turning angle of the steering wheel in response to a turning request to apply a yawing moment to the vehicle.
The vehicle is provided with an information output unit 26. The information output unit 26 displays images, generates sounds and turns on warning lights representing information about supporting operations according to the type of the driving support operation. The information output unit 26 is, for example, a monitor provided with a built-in loud speaker. Plural information output units may be installed in the vehicle.
The manipulated variable measuring unit receives values of manipulated variables altered by the driver in step s1. That is, the manipulated variable measuring unit receives signals representing a steering angle, the condition of the direction indicator, a movement of the accelerator pedal, a movement of the brake pedal and a set route. The manipulated variable measuring unit receives information about running speed, yaw rate, lateral acceleration and longitudinal acceleration from the measuring devices.
A position at a distance proportional to running speed Vx ahead of the vehicle is selected as a watch point P for control, and the distance is used as a front watch distance Xp. A lateral moving distance Yp by which the vehicle will move is estimated on an assumption that the vehicle arrives at the front watch point P in tps. When the vehicle is expected to move laterally, the front watch point P is at a forward distance Xp ahead of the vehicle and a lateral distance Yp in a lateral direction.
If the steering angle is zero, the vehicle travels a distance equal to Vx×tp forward and the lateral distance Yp is zero. When the lateral acceleration of the vehicle is ay, it is expected the lateral distance Yp is equal to ay×Δt2/2. Lateral acceleration can be calculated by using an expression: ay=Vx×r, where r is yaw rate measured by the operation parameter measuring unit or an expression: ay=Vx×f(δ), where f(δ) is a function expressing the relation between steering angle δ and yaw rate r. the function can be obtained through analysis using a motion model of a vehicle. The lateral acceleration may be determined by using an accurate analytical expression instead of using the foregoing expressions.
In step s2, the controller 1 determines a right lane marking LR and a left lane marking LL, respectively on the right and on the left side of a straight line (x-axis) passing the center of gravity of the vehicle on the basis of an image formed by the front camera 10f. Since lane markings are formed inmost cases on flat roads on which vehicles can travel, the vehicle can continue traveling even if the wheels move on the outer side of a lane marking. The respective distances from the x-axis of left lane markings LL1 to LL5 respectively at distances X1 to X5 ahead of the vehicle are calculated and stored. Positive values on a y-axis are on the left side of the vehicle, distances to the left from the x-axis are positive values, and distances to the right from the x-axis are negative values. Similarly, the respective distances from the x-axis of right lane markings LR1 to LR5 are calculated and stored. When right lane markings LR21 to LR25 of the adjacent lane can be detected, the right lane markings LR21 to LR25 are stored. Type, such as a continuous line or a broken line, the color, such as white, yellow or red, of the lane markings are recognized and stored to determine the degree of danger of crossing the lane marking and the degree of allowance.
In step s3, the controller 1 determines the respective positions of a right road boundary BR and a left road boundary BL on the right and the left side, respectively, of the x-axis on the basis of an image formed by the front camera 10f. It is comparatively difficult for the vehicle to continue running if the wheel crosses and moves beyond the road boundary. Distances from the x-axis of the positions of right road boundary marks BR1 to BR5 and those of left road boundary marks BL1 to BL5 respectively at distances X1 to X5 ahead of the vehicle are calculated and stored. At the same time, roadside areas 42R and 42L are recognized, and information about the type of the roadside areas 42R and 42L, such as edges of road shoulders, side ditches, curbs, embankments or guard rails, is stored to determine the degree of danger of crossing the road boundary and degree of allowance.
In steps s2 and s3, the lane is recognized on the basis of the image formed by the front camera 10f. Therefore, the driving support system can determine the position of the lane properly and ensures safe, comfortable driving without depending on road information and route information provided by a navigation system or the like. The lane may be recognized on the basis of images formed by the other cameras 10r, 12L, 12R, 13L and 13R. In most cases, the rear camera 10r is a wide-angle camera disposed with its optical axis inclined downward. Therefore, the type of the lane can be more accurately recognized when the rear camera 10r is used for recognizing the lane markings and road boundary marks defining the lane.
In step s4, the controller 1 determines a desired path or a desired running area to guide the vehicle into a route in the vicinity of the center of the lane or into a route that will scarcely give the driver a feeling of discomfort. The desired route or the desired running area is defined by guide lines, namely, first guide lines, NR and NL, namely, right and left thresholds for the driving support control. While the vehicle is in an area between the first lines NR and NL, preference is given to the operations of the driver and is a dead zone for control. A lane is a running area demarcated by lane markings or road boundary marks. When a right lane marking LR and a left lane marking LL are marked on the road, an area between the lane markings LR and LL is a running area. When a right lane marking LR and a left lane marking LL are not marked on the road, and area between the right road boundary BR and a left road boundary BL is a running area. When lane markings LR and LL are not marked intermittently and imaginary lane markings LR and LL can be supposed in intervals between the lane markings LR and LL through interpolation using the adjacent lane markings, and area between the imaginary lane markings are assumed to be a lane. When lane markings are marked on one of the opposite sides of a road, an area between the lane markings and the road boundary on the other side is a lane. The positions of left guide lines. NL1 to NL5 respectively at distances X1 to X5 ahead of the vehicle can be determined by subtracting a predetermined value ΔLL from or adding the same to the respective positions of the left lane markings LL1 to LL5. The positions of right guide lines NR1 to NR5 can be determined by subtracting a predetermined value ΔLR from or adding the same to the respective positions of the right lane markings LR1 to LR5.
In step s5, the controller 1 determines right and left contact avoidance lines AR and AL, namely, second lines, to avoid contact by moving the vehicle away from the road boundary. The positions of left contact avoidance lines AL1 to AL5 respectively at distances X1 to X5 ahead of the vehicle are determined by subtracting an avoidance allowance ΔAL from the positions of the left road boundary marks BL1 to BL5. The positions of right contact avoidance lines AR1 to AR5 respectively are determined by adding an avoidance allowance ΔAR to the positions of the right road boundary marks BR1 to BR5. The avoidance allowances ΔAL and ΔAR are determined taking into consideration the avoidance ability of the vehicle and taking into consideration at least one of factors including the longitudinal speed Vx of the vehicle, the lateral speed Vy of the vehicle, avoidance line approach speed Vya, longitudinal acceleration ax, lateral acceleration ay, overall width vw, overall length v1, tread d, wheelbase L, a maximum yawing moment Mmax that can be applied to the vehicle, a maximum deceleration axmax that can be achieved by the vehicle, a maximum lateral acceleration aymax that can be achieved by the vehicle, friction coefficient μ indicating the frictional property of the road surface, the slope θ of the road, the radius R of the curve, a distance and an angle that permit lane detection, and a distance and an angle that permit obstacle detection.
When the highest one of yawing moments that can be generated by the actuator is a maximum yawing moment Mmax, the maximum lateral aymax is calculated by using an expression: aymax=G×Mmax. A distance ΔYmax that will be traveled by the vehicle approaching the contact avoidance line at a lateral speed Vya and accelerated at the maximum lateral acceleration aymax before the lateral speed Vya decreases to zero can be calculated by using an expression: ΔYmax=Vya2/(2×aamax). To ensure avoiding contact with the road boundary, an inequality ΔAL>ΔYmax is satisfied to lighten damage resulting from contact, an inequality ΔAL≦ΔYmax is satisfied.
The maximum yawing moment Mmax is reduced and corrected according to the values of controlled variables representing motions of the vehicle with respect to the guide lines NR and NL, because a yawing moment is generated by guiding control at the start of a control operation for controlling the motion of the vehicle for contact avoidance and a limited additional yawing moment is available for contact avoidance. Therefore, a desired yawing moment at the start of the contact avoidance control is subtracted for correction from the maximum yawing moment Mmax that can be applied to the vehicle. Since the reduction of the contact avoiding ability of the vehicle by driving support by the first line can be thus taken into consideration and hence the safety of the driving support system can be enhanced.
In step s6, lane change is predicted from route information provided by the navigation system 6 and a signal provided when the driver operates the turn signal control lever 3. When the running vehicle is expected to change the route from the lane in which the vehicle is traveling at present to another lane, positions of the lane markings on a path along which the vehicle runs to change the route and the road boundary are determined, and then a decision is made as to whether or not the guide lines NL and NR need to be corrected. The driving support control procedure goes to step s8 when the vehicle is traveling on a single-lane road and lane change is not expected.
If lane change is expected in step s6, a guide line correction process is executed in step s7 to correct the guide lines NL and NR on the basis of the route information. The guide line correcting process will be described later with reference to
Obstacles on the route are detected in step s8. If an obstacle is detected, a decision is made in step s9 as to whether or not the right contact avoidance line AR and the left contact avoidance line AL need to be corrected. If any obstacle is not detected, the procedure goes to step s10. A contact avoidance line correction process is executed to correct the contact avoidance lines AR and AL on the basis of information about obstacles. The contact line correction process will be described later with reference to
Positions of guide lines NRp and NLp at a front watch distance Xp are determined by interpolation using five right guide lines NR1 to NR5 and five left guide lines NL1 to NL5. Positions of contact avoidance lines ARp and ALp at a front watch distance Xp are determined by interpolation using five right contact avoidance lines AR1 to AR5 and left contact avoidance lines AL1 to AL5. A decision is made in step s10 as to whether or not the driving support operation needs to be executed on the basis of the guide lines NRp and NLp and the contact avoidance lines ARp and ALp. If the front watch point P is on the inner side of the guide lines NRp and NLp and on the inner side of the contact avoidance lines ARp and ALp, the driving support operation is not executed and the driving support control procedure is ended. If the front watch point P is on the outer side of the guide line NRp or NLp or on the outer side of the contact avoidance line ARp or ALp, it is decided that the driving support control operations need to be executed and step s11 is executed. In
If the front watch point P is on the outer side of the guide line NLp or NRp, a desired yawing moment for guiding to a position on the inner side of the guide line NLp or NRp is calculated in step s11. To place importance on mitigating a feeling of discomfort felt by the driver, the driving support operation with reference to the guide line provides actuator selection information for selecting actuators to generate a yawing moment by the agency of the electronically controlled differential mechanism 23 and the electronically controlled steering system 24 instead of by the agency of the electronically controlled brake system 22 that decelerates the vehicle.
If the front watch point P is on the outer side of the contact avoidance line ARp or ALp, a desired yawing moment and a desired deceleration for moving the vehicle into an area between the contact avoidance line ARp and ALp are calculated. To place importance on preventing the vehicle 31 from running on the outer side of the road boundary and avoiding contact of the vehicle with an obstacle, a yawing moment and a deceleration are generated by the agency of the electronically controlled brake system 22 in addition to a yawing moment generated by the agency of the electronically controlled differential mechanism 23 and the electronically controlled steering system 24. If the right and the left contact avoidance line intersect each other, it is decided that contact cannot be avoided by a turning motion and a desired deceleration necessary for stopping the vehicle is calculated.
The car can be controlled so as to perform desired motions by using the control gains Gll and Glr dependent on the positional relation between the vehicle and the guide lines NR and NL, and the control gains Gar and Gal dependent on the positional relation between the contact avoidance lines AR and AL. Therefore, the driver can readily understand objects of driving support operations and an effect on mitigating a feeling of discomfort can be expected. Since the control variables can be selectively set according to objects, control operations can be easily tuned in designing the driving support system.
The gradient of a yawing moment increasing from the guide line toward the contact avoidance line is determined selectively according to the type of the lane marking. For example, a yawing moment increasing at a comparatively low gradient is used when the lane marking LR indicating the boundary between the adjacent lanes is a broken line, and a yawing moment increasing at a comparatively high gradient is used when the lane marking LR indicating the boundary between the adjacent lanes is a continuous line. Since the effect of a driving support operation using a yawing moment having such a gradient agrees with the degree of driver's consciousness when the driver is trying to keep the vehicle in the lane, the driving support system can still more effectively mitigate a feeling of discomfort. The lane marking LL on the side of the road boundary on most roads is a continuous line. Therefore, when a comparatively high gradient is used for indicating the slop of a yawing moment increasing toward a continuous line, the driving support system can still more effectively mitigate a feeling of discomfort because the effect of a driving support operation using a yawing moment having such a comparatively high gradient agrees with the degree of driver's consciousness when the driver is trying to move the vehicle away from the road boundary. It is highly possible that the vehicle is traveling on a road having three lanes on each of its sides when both the lane markings on the opposite sides of the lane are broken lines. In Japan, it is highly possible that a lane on the right side of a lane in which the vehicle is traveling and adjacent to the lane in which the vehicle is traveling is a passing lane. In such a case, a driving support operation agrees with the degree of driver's consciousness when the driver is trying to avoid contacting with a vehicle approaching the driver's vehicle from behind when the driving support operation uses a yawing moment increasing toward the passing lane and having a comparatively high gradient. Thus the driving support system can still more safely support driving operations and can still more effectively mitigate a feeling of discomfort.
The controller 1 executes a driving support control operation in step s12. The controller 1 uses at least one of the electronically controlled differential mechanism 23, the electronically controlled steering system 24 and the electronically controlled brake system 22 for controlling the motion of the vehicle to apply a desired yawing moment to the vehicle and to decelerate the vehicle at a desired deceleration or the controller 1 prompts the driver to correct driving operations by driving the information output unit 26 so as to display a warning, to generate a warning or to turn on a warning light. Then, the driving support control procedure is ended.
When an obstacle is detected in step s8, the contact avoidance line AR or AL is shifted inward in step s9. In a case shown in
When the actuator can generate the maximum yawing moment Mmax, the maximum lateral acceleration aymax is calculated by using an expression: aymax=G×Mmax. A distance ΔX to be traveled by the vehicle running forward at a forward velocity Vx toward the obstacle and laterally accelerated at a lateral acceleration ±aymax to avoid contact with the obstacle before the lateral speed of the vehicle drops to zero is calculated by using an expression: ΔX=Vx×√{square root over (ΔY/aymax)}. The maximum lateral acceleration ±aymax may be corrected according to the friction constant μ representing the frictional property of the road surface, the slop θ of the road and the radius R of the curve.
To avoid surely the contact of the vehicle with the obstacle, a contact avoidance operation for shifting the contact avoidance line AL to the right is started at a position on the side of the vehicle at a distance equal to or longer than the distance ΔX. The corrected left contact avoidance line has the shape of a combination of parabolic lines, provided that lateral movement is made at the maximum lateral acceleration aymax. The corrected left contact avoidance line may have any shape, provided that the corrected left contact avoidance line can ensure the avoidance of contact between the vehicle and the obstacle. The contact avoidance operation for shifting the contact avoidance line AL to the right may be started at a position on the side of the vehicle at a distance not longer than the distance ΔX if contact between the vehicle and the obstacle is permitted and the object of the contact avoidance operation is to reduce damage to the vehicle.
If an opposing vehicle 33 is traveling in an opposing lane as shown in
When the two types of reference lines, namely, the guide lines NR and NL, and the contact avoidance lines AR and AL, are used for driving support operations, the contact avoidance lines AR and AL can be corrected with the guide lines NR and NL fixed. Thus the driving support operation can be executed without making the driver feel a feeling of discomfort when there is no danger of contact between the vehicle and the obstacle, and the driving support operation to avoid contact between the vehicle and the obstacle can be achieved.
When the contact avoidance line AL or AR is corrected, the guide line NL or NR is corrected again so that the guide line NL or NR is on the inner side of the contact avoidance line AL or AR to carry out the driving support operation safely and to mitigate a feeling of discomfort that may be given to the driver by the driving support operation. When an obstacle 34, namely, a vehicle, shown in
A correcting process for correcting the guide line NL or NR or the contact avoidance line AL or AR is executed in step s7 on the basis of information about the route when it is decided in step s6 that the route is to be changed. When it is decided that the route along which the vehicle 31 is traveling at present is changed for a branch route branching from the lane in which the vehicle 31 is traveling at present as shown in
A driving support operation for supporting operations for changing the route uses the right and the left guide line spaced apart by a distance shorter than those used for controlling the operation for guiding the vehicle 31 within the lane. The width of a space between the left guide lines NL1 to NL5 and the right guide lines NR1 to NR5 is equal to or smaller than the overall width vw of the vehicle 31. Thus the length of a running section in which the motion of the vehicle 31 is controlled positively increased, so that support operation ensures a smooth route changing operation. For example, it is possible that the vehicle 31 meanders if the right and the left guide line are spaced wide apart. Such possibility can be suppressed by using the right and the left guide line extended at a short distance from each other. After step s7 has been completed, operations for controlling the vehicle 31 in a state where an obstacle is on the route is executed in step s8.
In step s8, an obstacle on an estimated route is detected and a decision is made as to whether or not the correction of the contact avoidance lines AL and AR is necessary. The procedure goes to step s9 if an obstacle 35, such as a parking vehicle shown in
The contact avoidance line AR is shifted inward as shown in
The driving support operation for this correction taking both route change and contact avoidance into consideration can be started while the vehicle 31 is in the lane in which the vehicle 31 is traveling at present. Therefore, contact avoidance operations for preventing the vehicle 31 from coming into contact with the obstacle 35 can be started when the vehicle 31 is at a position shown in
A correcting process for correcting the guide lines NL and NR and the contact avoidance lines AL and AR is executed in step s7 on the basis of information about the route when it is decided in step s6 that the route is to be changed. Lane change to a lane adjacent to the lane in which the vehicle 31 is traveling at present can be known from information about the operation of the turn signal control lever 3. When it is decided that the vehicle 31 is going to move from the lane in which the vehicle 31 is traveling at present into a lane adjacent to the former as shown in
It is decided in step s8 that the contact avoidance lines AR and AL need to be corrected when an obstacle in an expected lane is detected. Obstacles around the vehicle 31 are detected in addition to the obstacle in front of the vehicle 31 by using the rear camera 10r, the rear radar 11r, the left front camera 12L, the right front camera 12R, the left rear camera 13L and the right rear camera 13R. When an obstacle 36 shown in
The driving support operation for this correction taking both route change and contact avoidance into consideration can be started while the vehicle 31 is in the lane in which the vehicle 31 is traveling at present. Therefore, guiding operations for guiding the vehicle 31 into the expected lane taking an obstacle into consideration can be stated when the vehicle 31 is at a position shown in
This driving support operation does not execute positive guidance like that mentioned in connection with
A correcting process for correcting the guide lines NL and NR and the contact avoidance lines AL and AR is executed in step s7 on the basis of information about the route when it is decided in step s6 that the route is to be changed. Lane change to a lane adjacent to the lane in which the vehicle 31 is traveling at present can be known from information about the operation of the turn signal control lever 3. When it is decided that the vehicle 31 is going to move from the lane in which the vehicle 31 is traveling at present into a lane adjacent to the former as shown in
It is decided in step s8 that the contact avoidance line AR needs to be corrected when an obstacle in an expected lane is detected. Obstacles around the vehicle 31 are detected in addition to an obstacle in front of the vehicle 31 by using the rear camera 10r, the rear radar 11r, the right front camera 12R and the right rear camera 13R. When a vehicle 37 approaching the vehicle 31 from behind as shown in
The driver is warned of danger by a warning sound a warning light and/or a warning image immediately after the turn signal control lever has been operated. The warning sound given immediately after the operation of the turn signal control lever 3 when the vehicle 31 is at a position 31a shown in
The driving support system in this embodiment performs driving support operations on the basis of the positional relation between the vehicle and the guide lines (first lines) or the contact avoidance lines (second lines). Reference lines for driving support operations are not limited to the guide lines and the contact avoidance lines. For example, the contact avoidance lines may be those that allow the vehicle to come into contact with an obstacle in a low degree and those that do not permit contact at all and enable using a sufficient time for controlling the vehicle so that the vehicle can smoothly avoid coming into contact with an obstacle. Expected damage that may be caused by an obstacle is estimated on the basis of the type of the obstacle, and the two types of contact avoidance lines may be selectively used to achieve a safe driving support operation scarcely giving the driver a feeling of discomfort. Two types of guide lines maybe selectively used to use different control gains selectively. Since the effect of control can be thus adjusted according to the object of guiding, the driving support system will give the driver a less feeling of discomfort. Guide lines and contact avoidance lines may be generated according to circumstances to carry out the driving support operation in three or more modes. Thus, a highly expandable driving support system that will scarcely give the driver a feeling of discomfort can be provided.
Although the driving support system in the preferred embodiment has been described as applied to controlling motions of a vehicle during rout change from the lane in which the vehicle is traveling at present to the branch lane and from the lane in which the vehicle is traveling at present to the lane adjacent to the lane-in which the vehicle is traveling at present, the present invention is applicable to controlling a vehicle in various traveling modes including those for running into the junction of roads, for passing a crossroad, selecting a gate of a tollgate lane change to a right-turn lane and lane change to a left-turn lane. When the driving support system is expanded to cope with those expected traveling modes, the driving support system will ensure safer traveling and scarcely give the driver a feeling of discomfort.
Claims
1. A driving support system comprising:
- a lane detecting unit for detecting lanes around a vehicle;
- a route correcting unit for correcting a route along which the vehicle is expected to travel taking into consideration an obstacle on the route after the route has been recognized by lanes detected by the lane detecting unit; and
- a control unit for controlling the vehicle on the basis of the positional relation between the corrected route determined by the route correcting unit and the vehicle.
2. The driving support system according to claim 1, wherein the control unit starts controlling the vehicle when it is decided that the vehicle changes the route from a lane in which the vehicle is traveling at present to another lane in which a obstacle lies on the basis of information about the obstacle while the vehicle is traveling in the lane in which the vehicle is traveling at present.
3. The driving support system according to claim 1, wherein the detecting unit includes imaging devices for forming images of matters around the vehicle, and a lane recognizing device for recognizing lanes by images of lane markings or road boundaries formed by the imaging devices.
4. A driving support system comprising:
- a line generating unit capable of generating first lines for guiding a vehicle to a desired route along which a vehicle is expected to travel, and second lines for preventing the vehicle from coming into contact with an obstacle; and
- a control unit for controlling the vehicle on the basis of the positional relation between the vehicle and at least one of the first and the second lines.
5. A driving support system comprising:
- a lane detecting unit for detecting lanes around a vehicle;
- a line generating unit capable of determining a route along which the vehicle is expected to travel on the basis of lanes detected by the lane detecting unit, of generating first lines for guiding the vehicle so as to travel along the determined route, and of generating second lines for preventing the vehicle coming into contact with an obstacle on the basis of the first lines; and
- a control unit capable of controlling the vehicle on the basis of the positional relation between the vehicle, and the first and the second lines.
6. The driving support system according to claim 4, wherein the line generating unit generates the first lines on the basis of detected lane markings around the vehicle or detected road boundaries, and generates the second lines on the basis of positions of detected road boundaries or an obstacle around the vehicle.
7. The driving support system according to claim 4, wherein different control gains and different actuators are used respectively for controlling motions of the vehicle based on the positional relation between the vehicle and the first lines, and motions of the vehicle based on the positional relation between the vehicle and the second lines.
8. The driving support system according to claim 6, wherein at least one of shape, color, number of lane markings, intervals between lane markings and legal meanings of lane markings is determined, and at least one of a route to which the vehicle is to be guided, values of controlled variables of the vehicle, and giving information to a driver driving the vehicle is adjusted according to a result of the determination.
9. The driving support system according to claim 1, wherein the obstacle is at least one of other vehicles, pedestrians, animals, objects dropped on roads, road shoulders, ditches, embankments and guardrails, and at least one of a route for avoiding contact between the vehicle and the obstacle, values of controlled variables for controlling motions of the vehicle, and a method giving a driver driving the vehicle information is changed according to the type of the obstacle.
10. The driving support system according to claim 4, wherein the line generating unit generates the second lines on the basis of at least one of data on traveling speed, acceleration, overall width, overall length, tread and wheelbase of the vehicle, yawing moment generating capacity of the vehicle, braking capacity of the vehicle, friction coefficient representing frictional property of the road, gradient of the road, radius of curvature of a curve, distance and angle allowing lane detection, and distance and angle allowing obstacle detection.
11. The driving support system according to claim 4, wherein the line generating unit generates the second lines on the basis of values of controlled variables for controlling motions of the vehicle determined on the basis of the positional relation between the vehicle and the first lines or information given to a driver driving the vehicle.
12. The driving support system according to claim 4, wherein the second lines are a right second line and a left second line, the first line is corrected when the left second line is on the right side of the first line so that the left second line is on the right side of the first line or the first line is corrected when the right second line is on the left side of the first line so that the first line is on the left side of the second line.
13. The driving support system according to claim 4, wherein the second lines are a right second line and a left second line, and the control unit decelerates the vehicle when the right and the left second line intersect each other.
14. A driving support system comprising:
- a lane detecting unit for detecting lanes around a vehicle;
- a route correcting unit for correcting a route along which the vehicle is expected to travel taking into consideration an obstacle on the route after the route has been recognized by lanes detected by the lane detecting unit; and
- an information output unit for giving information about the route based on the positional relation between the corrected route corrected by the route correcting unit and the vehicle to a driver driving the vehicle.
Type: Application
Filed: Aug 20, 2008
Publication Date: Apr 2, 2009
Applicant: Hitachi, Ltd. (Tokyo)
Inventors: Atsushi YOKOYAMA (Tokyo), Shinjiro SAITO (Hitachinaka), Masatsugu ARAI (Kasumigaura), Tatsuya YOSHIDA (Naka)
Application Number: 12/195,032
International Classification: G01C 21/34 (20060101); G01C 21/20 (20060101);