JP3859905B2 - Vehicle steering control device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vehicle steering control device.
[0002]
[Prior art]
As a vehicle steering control apparatus, the present applicant calculates a target yaw rate from a vehicle speed and a rudder angle detected using a yaw rate reference model in Japanese Patent Laid-Open No. 7-47970, and calculates a target locus from the calculated target yaw rate. And a technique for assisting the steering torque in accordance with the deviation from the actual locus calculated from the detected yaw rate.
[0003]
Further, for example, in Japanese Patent Application Laid-Open No. 5-197423 and Japanese Patent Application Laid-Open No. 9-221054, the present applicant detects the white line of the traveling road (lane) by imaging the vehicle traveling direction, and the vehicle along the detected white line. Has been proposed to assist the steering angle so that the vehicle runs.
[0004]
Thus, the driver's burden can be greatly reduced by assisting the minute steering through the lane keeping steering assist control that prevents the vehicle from deviating from the traveling path. The burden on the driver is particularly noticeable when traveling on a highway for a long time.
[0005]
[Problems to be solved by the invention]
By the way, in order to perform the above-mentioned lane keeping steering assist control with high accuracy, it is necessary to detect the white line to the front to some extent and accurately recognize the traveling path, but other vehicles intrude from the adjacent lane (lane) depending on the traveling situation. However, there may be a case where the white line cannot be detected sufficiently, such as traveling across the white line.
[0006]
In such a case, if the lane keeping steering assist control is stopped each time and is restarted when the white line can be detected, the stop and restart are repeated to reduce comfort.
[0007]
In particular, the above-described inconvenience becomes noticeable when the preceding vehicle follow-up running control is performed in addition to the lane keeping steering assist control in addition to the preceding vehicle follow-up running control in which the following vehicle is followed at the set inter-vehicle distance (time).
[0008]
Accordingly, an object of the present invention is to eliminate the above-described inconveniences, and when the lane keeping steering assist control is being executed, even when a situation where a white line cannot be detected occurs, the lane keeping steering assist control is stopped and resumed. It is an object of the present invention to provide a vehicular steering control device that avoids the repetition of the above, and thus prevents a decrease in comfort.
[0009]
The second object of the present invention is to repeatedly stop and restart the lane keeping steering assist control even when the white line cannot be detected when the lane keeping steering assist control and the preceding vehicle following travel control are executed together. It is an object of the present invention to provide a vehicle steering control device that avoids and thus prevents a decrease in comfort.
[0010]
[Means for Solving the Problems]
  In order to achieve the above object, according to claim 1, there is provided a vehicle steering control device including an actuator for turning a steering wheel of a vehicle, the imaging means for imaging the front of the vehicle, and the imaging means. A road detection means for detecting a road based on the image information obtained byDeceleration means for decelerating the vehicle;And a steering assist amount for driving the vehicle along the detected travel path is calculated, and the actuator is driven and controlled based on the calculated steering assist amount.And controlling the operation of the deceleration meansIn a vehicle steering control device comprising steering assist control means,Navigation deviceAnd the steering assist control means includes the travel path detection means.Cannot detect the travel path, and when the navigation device determines that the vehicle is traveling on a highway,Activating the deceleration meansDo not let the vehicle fall below a certain speedIt was configured to decelerate.
[0011]
  When the steering assist control means cannot detect the travel path,And when it is determined by the navigation device that the vehicle is traveling on the highway,Activating the deceleration meansKeep the vehicle below the prescribed speedSince it was configured to decelerate, in other words,Keep the vehicle below the prescribed speedSince the steering assist control is continued while decelerating, even when the white line cannot be detected when the lane keeping steering assist control is executed, the lane keeping steering assist control is repeatedly stopped and restarted. Can prevent a decrease in comfort.
[0012]
  Claim2The vehicle steering control device includes an actuator that steers the steering wheel of the vehicle, the imaging means for imaging the front of the vehicle, and the travel path based on the image information obtained by the imaging means. Traveling path detection means for detecting,Follow-up running control means for running following the preceding vehicle running in front of the vehicle,And a steering assist amount for driving the vehicle along the detected travel path is calculated, and the actuator is driven and controlled based on the calculated steering assist amount.And controlling the operation of the following traveling control meansIn the vehicle steering control device including the steering assist control means,Navigation deviceAnd the travel path detecting meansCannot detect the travel path, and when the navigation device determines that the vehicle is traveling on a highway,Activating the following travel control meansDo not let the vehicle fall below a certain speedIt was configured to decelerate.
[0013]
  When the steering assist control means cannot detect the travel path,And when it is determined by the navigation device that the vehicle is traveling on the highway,Activate the tracking control meansKeep the vehicle below the prescribed speedSince it was configured to decelerate, in other words,Keep the vehicle below the prescribed speedSince the steering assist control is continued while decelerating, the lane keeping steering assist control is stopped and resumed even when the white line cannot be detected when the lane keeping steering assist control and the preceding vehicle following running control are executed together. It is possible to prevent the comfort from being reduced by avoiding the repetition of.According to a third aspect of the present invention, there is provided a vehicle steering control device including an actuator for turning a steering wheel of a vehicle, the imaging means for imaging the front of the vehicle, and the image information obtained by the imaging means. A travel path detecting means for detecting the travel path, a deceleration means for decelerating the vehicle, a steering assist amount for causing the vehicle to travel along the detected travel path, and calculating the calculated steering assist amount. And a steering assist control unit for controlling the operation of the speed reduction unit. The vehicle steering control device includes a navigation device, and the steering assist control unit includes: When the detection means cannot detect the travel path, and the navigation device determines that the vehicle is traveling on an expressway. The vehicle is decelerated so as not to fall below a predetermined speed by operating the deceleration means, and the deceleration of the vehicle is canceled based on the detection result of the travel path by the travel path detection means. did. According to a fourth aspect of the present invention, there is provided a vehicle steering control device including an actuator for turning a steering wheel of a vehicle, the imaging means for imaging the front of the vehicle, and the image information obtained by the imaging means. A travel path detecting means for detecting the travel path, a follow-up travel control means for following the preceding vehicle traveling in front of the vehicle, and a steering assist amount for causing the vehicle to travel along the detected travel path. A vehicle steering control device including a steering assist control unit that calculates and controls the drive of the actuator based on the calculated steering assist amount and controls the operation of the follow-up travel control unit, and includes a navigation device. When the travel path detection means cannot detect the travel path, and the navigation device causes the vehicle to travel on a highway. When it is determined that the vehicle travels, the following travel control means is operated to decelerate the vehicle so as not to fall below a predetermined speed, and the vehicle is decelerated based on the detection result of the travel path by the travel path detection means. It was constituted to cancel.
[0014]
The reason why the steering assist amount is described above is that the steering assist may be torque or steering angle. In the embodiment described later, torque is used.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the accompanying drawings.
[0016]
FIG. 1 is a schematic view generally showing a vehicle steering control device according to this application, and FIG. 2 is a similar explanatory view showing the device with a focus on a steering system.
[0017]
In the following, referring to FIG. 1 and FIG. 2 together, the steering wheel 14 disposed in the driver's seat 12 of the vehicle 10 is connected to the steering shaft 16, and the steering shaft 16 is connected via universal joints 18 and 20. Connected to the connecting shaft 22.
[0018]
The connecting shaft 22 is connected to a pinion 26 of the rack and pinion type steering gear 24. The pinion 26 meshes with the rack 28, so that the rotational motion input from the steering wheel 14 is converted into the reciprocating motion of the rack 28 through the pinion 26, and tie rods (steering rods) 30 disposed at both ends of the front axle and Two front wheels (steering wheels) 32 are steered in a desired direction via a kingpin (not shown).
[0019]
An electric motor 38 and a ball screw mechanism 40 are coaxially disposed on the rack 28, and the motor output is converted into a reciprocating motion of the rack 28 via the ball screw mechanism 40, and the steering force (input via the steering wheel 14 ( The rack 28 is driven in the direction of decreasing the steering torque.
[0020]
Here, a torque sensor 42 is provided in the vicinity of the steering gear 24 and outputs a signal corresponding to the direction and magnitude of the steering force (steering torque) input by the driver. A steering angle sensor 44 including a rotary encoder is provided in the vicinity of the steering shaft 16, and a signal corresponding to the direction and magnitude of the steering angle (steering angle, more specifically, the front wheel steering angle) θ input by the driver. Is output.
[0021]
A wheel speed sensor 46 composed of an electromagnetic pickup or the like is disposed in the vicinity of the two front wheels 32 to output a signal for each rotation of the front wheel, and a wheel speed sensor of the same structure also in the vicinity of the two rear wheels 48. 50 are arranged to output a signal for each rotation of the rear wheel (only the left rear wheel is shown in FIG. 1). In the vehicle 10, an internal combustion engine (not shown) is disposed on the front wheel side, and the front wheel 32 is a driving wheel and the rear wheel 48 is a driven wheel.
[0022]
Further, vehicle height sensors 52 and 54 are provided in the vicinity of the suspension mechanism (not shown) of the two front wheels 32 and the two rear wheels, respectively, and the vehicle at that portion is provided through the stroke (displacement) of the suspension of the front and rear wheels. A signal corresponding to the height of 10 is output.
[0023]
As shown in FIG. 1, a CCD camera (imaging means) 64 is attached to the upper portion of the driver seat 12 in combination with a room mirror 62 on the inner surface of the front window 60. As shown in FIG. 7 to be described later, the CCD camera 64 monocularly views the road in the vehicle traveling direction, images the traveling road surface from the point 30 to 60 m ahead, and outputs an image signal.
[0024]
As shown in FIG. 2, the output of the CCD camera 64 is sent to an image processing ECU (running path detection means) 66 composed of a microcomputer, and from an imaging signal in the above-mentioned range to a gazing point ahead of about 30 to 60 m. A dividing line (white line) of the lane (lane) of the travel path is extracted.
[0025]
Further, a laser radar (shown as “radar” in FIG. 2) 68 is provided at an appropriate position near the front bumper of the vehicle 10. The laser radar 68 sends a light transmission beam forward in the traveling direction of the vehicle and sweeps it in the left and right (vehicle width) direction to scan a predetermined range. When an obstacle such as a solid object, for example, a preceding vehicle is present ahead The reflected light of the light transmission beam reflected by the reflector is received.
[0026]
The laser radar 68 is connected to a radar output processing ECU 70 composed of a microcomputer, where a distance to an obstacle (reflector) such as a preceding vehicle is calculated based on a time difference from transmission of a light transmission beam to reception of reflected light. At the same time, the direction of the obstacle is detected based on the transmission direction of the light transmission beam when the reflected light is received.
[0027]
The vehicle steering control device according to this application is similarly provided with a first electronic control unit (referred to as “SAS ECU”) 74 formed of a microcomputer, and outputs from the image processing ECU 66 and the torque sensor 42 described above are SAS ECU 74. Is input.
[0028]
The apparatus also includes a second electronic control unit (referred to as “EPS ECU”) 76. The outputs of the torque sensor 42 and the wheel speed sensor 46 described above are also input to the EPS ECU 76.
[0029]
The SAS ECU 74 and the EPS ECU 76 are connected to each other via a signal line 78 so that they can communicate with each other. As will be described later, the SAS ECU 74 calculates a lane keeping steering assist torque (steering assist amount) and transmits it to the EPS ECU 76.
[0030]
When the steering torque is detected, the EPS ECU 76 calculates the power steering steering assist torque accordingly, calculates the final steering assist torque based on the lane keeping steering assist torque and the power steering steering assist torque, and then the operation amount (electric The control current of the motor 38) is determined.
[0031]
A motor drive circuit 80 is connected to the EPS ECU 76. The motor drive circuit 80 includes a known bridge circuit (not shown) composed of four power FET switching elements, and the electric motor 38 is rotated forward or backward by turning on / off the FET switching elements.
[0032]
The EPS ECU 76 determines the motor control current by the duty ratio (duty ratio by PWM) and outputs it to the motor drive circuit 80. More specifically, the EPS ECU 76 controls the motor energization current by controlling the duty ratio of the FET switching element, and drives and controls the electric motor 38.
[0033]
Returning to the description of FIG. 1, the yaw rate sensor 82 is disposed near the center of gravity of the vehicle 10 and outputs a signal corresponding to the yaw rate (rotational angular velocity; vehicle turning behavior) about the vertical (gravity) axis of the center of gravity of the vehicle. The output of the yaw rate sensor 82 is input to the SAS ECU 74.
[0034]
Further, an alarm device 84 is provided near the dashboard of the driver's seat 12 to notify the driver of the alarm by voice or vision, and similarly, a navigation device 88 is disposed near the dashboard (in FIG. 1). Indicated as “NAVI”).
[0035]
The navigation device 88 is a CPU 88a, a CD-ROM 88b that stores navigation information indicating the vehicle travel planned area by a number of nodes (coordinate position information), and a GPS receiver (“GPS” that receives signals from GPS via an antenna 88c. 88d).
[0036]
The CPU 88a of the navigation device 88 and the SAS ECU 74 are connected so as to be capable of two-way communication, and the SAS ECU 74 inputs the navigation information consisting of the above-mentioned many nodes via the CPU 88a and schedules the vehicle to travel from an adjacent node group as will be described later. The curvature R of the area is calculated, and the detected steering angle is corrected from the calculated value.
[0037]
Further, a brake switch 90 is provided on a brake pedal (not shown) on the floor surface of the driver's seat 12 to output a signal corresponding to the driver's depression of the brake pedal, and to an accelerator pedal (not shown). An accelerator sensor 92 is provided and outputs a signal corresponding to the driver's depression of the accelerator pedal.
[0038]
Furthermore, the vehicle steering control device according to this embodiment includes a following (constant speed) traveling control function.
[0039]
That is, in the vicinity of the steering wheel 14 arranged in the driver's seat 12 of the vehicle 10, after the constant speed running control is interrupted by a set switch 100 for inputting a constant speed running command by the driver and a brake operation or the like. Input a resume switch 102 for inputting a return command, a cancel switch 104 for inputting a cancel command for a constant speed travel command, and a command for setting the inter-vehicle distance to the preceding vehicle to one of far, middle, and near In order to do this, an inter-vehicle switch 106 is provided.
[0040]
The outputs of the switches 100, 102, 104, 106, the brake switch 90, the yaw rate sensor 82, the wheel speed sensor 46, the radar output processing ECU 70, and the like are similarly composed of a microcomputer and execute tracking (constant speed) traveling control. It is input to a third electronic control unit (shown as “ACC ECU”) 110 (illustration of switch 100 and the like and input to ACC ECU 110 are omitted in FIG. 2).
[0041]
The ACC ECU 110 includes a throttle actuator 120 (not shown in FIG. 2). The throttle actuator includes a diaphragm (not shown), a link mechanism (not shown) for connecting a diaphragm (not shown) and a throttle valve (not shown) disposed in an intake pipe (not shown) of the internal combustion engine, and an intake pipe The throttle opening is increased / decreased by introducing a negative pressure downstream of the throttle valve through a branch path to control the vehicle speed. The details of the throttle actuator are described in detail in Japanese Patent Laid-Open No. 9-207616, so the description will be limited to this level.
[0042]
In addition, the ACC ECU 110 includes a brake actuator (deceleration means, not shown in FIG. 2) 122. The brake actuator 122 includes a negative pressure booster (not shown), and the negative pressure booster includes a chamber into which negative pressure is introduced from the engine intake system and a chamber into which atmospheric pressure is introduced, which are defined by the same type of diaphragm. By adjusting the ratio of atmospheric pressure and negative pressure via an electromagnetic valve (not shown), the brake pressure is supplied from the master cylinder (not shown) to the front wheel 32 and the rear wheel independently of the driver's brake operation. 48 brake devices (not shown) are operated to decelerate the vehicle 10.
[0043]
The ACC ECU 110 receives the sensor output described above and operates the throttle actuator 120 and the brake actuator 122 as necessary to perform follow-up (constant speed) travel control, which will be described later. The ACC ECU 110 is connected to the SAS ECU 74 so that they can communicate with each other.
[0044]
Before entering the description of the figure, the lane keeping steering assist control in the operation of this apparatus will be outlined with reference to the block diagram of FIG.
[0045]
The output of the CCD camera 64 is input to the image processing ECU 66, where the condition of the road on which the vehicle 10 is traveling, more specifically, the white line of the road or lane (lane) is detected.
[0046]
On the other hand, the local node group (coordinate position information) is output as navigation information from the navigation device 88, and the SAS ECU 74 selects some of the adjacent node groups and calculates the curvature R of the traveling road.
[0047]
FIG. 5 shows the curvature R of the travel path obtained from the navigation information. The SAS ECU 74 corrects the detected steering angle θ (the steering angle of the front wheels 32) from the travel path state thus obtained, more specifically, from the curvature R of the travel path.
[0048]
Next, the SAS ECU 74 calculates a target yaw rate (target vehicle turning behavior) γm from the corrected steering angle θ and the vehicle speed V using a yaw rate reference model represented by the following equation.
[0049]
γm = θ · V / ((1 + A · V²) ・ L)
In the above, L is the wheelbase length of the vehicle 10 and is obtained in advance. A is a stability factor, which is calculated from the following equation.
A = (− M / 2L²) · (Lf · Kf−Lr · Kr) / Kf · Kr
[0050]
In the above, M is the moment of inertia of the vehicle 10, Lf is the distance from the center of gravity of the vehicle 10 to the front wheel 32, Kf is the cornering force of the front wheel 32, Lr is the distance from the center of gravity of the vehicle 10 to the rear wheel 48, and Kr is the rear wheel. The cornering force of 48 is obtained in advance.
[0051]
If the explanation of FIG. 4 is continued, then, a deviation Δγ between the calculated target yaw rate γm and the detected actual yaw rate γ is calculated, the calculated value is multiplied by an appropriate gain (not shown), and the vehicle 10 moves along the lane. For example, the lane keeping steering assist torque (steering assist amount; hereinafter referred to as “assist torque TLK”) necessary for traveling along or near the lane center is calculated.
[0052]
By performing such control, as shown in FIG. 5, for example, steering is assisted so that the vehicle 10 that is directed in a direction parallel to a straight line is directed in a direction indicated by a broken line in accordance with the lane alignment.
[0053]
When steering torque τh is detected, that is, when steering torque is input by the driver, power steering steering assist torque (hereinafter referred to as “assist torque TPS”) is calculated by multiplying the detected torque τh by an appropriate gain. To do. The assist torque TPS is assist torque when the driver performs active steering such as avoiding an obstacle on the road.
[0054]
In FIG. 4, the process performed by the SAS ECU 74 is denoted as “SAS”, and the process performed by the EPS ECU 76 is denoted as “EPS”. In this embodiment, the steering assist torque control for lane keeping is performed by using a conventional power steering actuator (electric motor 38), thereby simplifying the configuration.
[0055]
FIG. 6 shows the characteristics of the assist torque TLK and the assist torque TPS determined as described above. The control shown in the block diagram of FIG. 4 gives the assist torque as shown in the figure according to the deviation Δγ or the detected torque τh.
[0056]
The value of the assist torque TLK is corrected according to the driver steering torque (detected torque) τh and the detected steering angle θ, which will be described later.
[0057]
Based on the above, the lane keeping steering assist control in the operation of the vehicle steering control device according to this application will be described with reference to the flowchart of FIG. The illustrated program is executed every 66 msec, for example.
[0058]
First, in S10, it is determined whether or not a white line from the 30 m to the 60 m ahead is detected. As described above, as shown in FIG. 7, when the preceding vehicle 200 travels across the white line 300 or when the distance from the other preceding vehicle 202 is short, the detection of the white line 300 up to the front gazing point is detected. There is a situation where it becomes impossible. In general, the length of the white line is 12 m, and the interval between the white lines is 8 m.
[0059]
When the result in S10 is affirmative, the process proceeds to S11, and the navigation information, image processing result, and sensor output (yaw rate γ, vehicle speed V, steering angle θ, driver steering torque τh, etc.) are read.
[0060]
Next, in S12, the detected steering angle θ is corrected from the traveling road state (curvature R or the like) based on the navigation information, and the target yaw rate γm is calculated from the corrected steering angle θ and the detected vehicle speed V using the yaw rate reference model described above.
[0061]
Next, in S14, a deviation Δγ between the calculated target yaw rate γm and the detected actual yaw rate γ is calculated as shown in the figure.
[0062]
Next, in S16, it is determined whether or not the calculated deviation Δγ exceeds a predetermined value γref in absolute value. When the result in S16 is negative, it is determined that the vehicle 10 is traveling along or near the lane center position, so the process proceeds to S18, and the values of timers (up counters) T1, T2 (described later) are set to 0. Do (start).
[0063]
Next, in S20, the steering assist torque TLK is calculated according to the characteristic shown in FIG. 6 according to the deviation Δγ.
[0064]
On the other hand, when the result in S16 is affirmative, the routine proceeds to S22, in which the deviation Δγ is 0 or more, that is, the deviation Δγ is a positive value, in other words, the actual yaw rate is insufficient with respect to the target yaw rate, or the negative side In other words, it is determined whether or not the actual yaw rate exceeds the target yaw rate.
[0065]
When the result in S22 is affirmative and it is determined that the actual yaw rate is insufficient with respect to the target yaw rate, the process proceeds to S20 via S18, and the assist torque TLK is calculated according to the deviation Δγ.
[0066]
On the other hand, when the result in S22 is negative and it is determined that the actual yaw rate exceeds the target yaw rate, the process proceeds to S24 to determine whether or not the detected torque τh exceeds the first predetermined torque τhref1.
[0067]
The first predetermined torque τhref1 is set to a value sufficient to estimate that the driver intends to actively steer by avoiding obstacles on the road, for example, 10 kgf · cm.
[0068]
When the result in S24 is affirmative, the driver intends to actively steer and proceeds to S26 in order to prevent the lane keeping steering assist control from interfering with the driver's aggressive steering operation. The assist torque TLK is set to zero. That is, the lane keeping steering assist control is stopped.
[0069]
As a result, as shown in the block diagram of FIG. 4, the EPS ECU 76 calculates the assist torque TPS for the power steering according to the characteristics shown in FIG. 6 in accordance with the detected torque τh. Steering motion is assisted.
[0070]
When the result in S24 is negative, the program proceeds to S28, in which it is determined whether or not the detected torque τh is equal to or smaller than a second predetermined torque τhref2.
[0071]
The second predetermined torque τhref2 is set to a value, for example, 5 kgf · cm, which is sufficient for the driver to estimate a state where the driver relies too much on the lane keeping steering assist control and the gripping force of the steering wheel 14 is weak.
[0072]
When the result in S28 is negative, it is unlikely that the driver is excessively dependent on the lane keeping steering assist control, so the process proceeds to S20 via S18, and the assist torque TLK is calculated according to the deviation Δγ.
[0073]
On the other hand, when the result in S28 is affirmative, it is presumed that the driver is excessively dependent on the lane keeping steering assist control, so the process proceeds to S30, and the steering angle θ detected for further confirmation is the predetermined steering angle. It is determined whether or not θref is exceeded.
[0074]
This predetermined rudder angle θref is also set to a value, for example, 5 degrees, which is sufficient for the driver to confirm the state of being too dependent on the lane keeping steering assist control.
[0075]
When the result in S30 is negative, since it is not confirmed that the driver is excessively dependent on the lane keeping steering assist control, the process proceeds to S20 via S18, and the assist torque TLK is calculated according to the deviation Δγ.
[0076]
On the other hand, when the result in S30 is affirmative, the process proceeds to S32, where it is determined whether or not the value of the timer T1 is equal to or longer than a first predetermined time Tref1 (for example, 2 sec), and when the result is negative, the process proceeds to S20.
[0077]
On the other hand, when the result in S32 is affirmative, the process proceeds to S34, where a warning / warning operation is performed to the driver via the alarm device 84, and the driver's attention is alerted to increase the grip of the steering wheel 14. .
[0078]
Next, the process proceeds to S36, in which it is determined whether or not the value of the timer T2 is equal to or longer than a second predetermined time Tref2 (for example, 5 sec). If the result is negative, the process proceeds to S20, and if the result is positive, the process proceeds to S38. The driver is notified in the same manner, and the process proceeds to S26, where the assist torque TLK is set to zero and the lane keeping steering assist control is stopped.
[0079]
As a result, the steering torque experienced by the driver increases, and this can alert the driver more carefully. In addition, after stopping the lane keeping steering assist control as described above, when the driver instructs the lane keeping steering assist control again, the control is resumed.
[0080]
On the other hand, when the result in S10 is negative, the process proceeds to S40, a deceleration command is sent to the ACC ECU 110, and the process proceeds to S42. Similarly, a warning / warning operation is performed to the driver via the alarm device 84, and the driver's attention is given. Arouse. That is, in this case, since the forward gazing point (for example, 30 m ahead) cannot be detected, the detection accuracy of the travel path is not sufficient, so the lane keeping steering assist control is continued while the vehicle 10 is decelerated. .
[0081]
FIG. 8 is a flowchart showing a tracking (constant speed) traveling control operation in the operation of the apparatus according to this embodiment. The illustrated program is executed every 200 msec, for example.
[0082]
First, in S100, it is determined whether or not the cancel switch 104 is turned on, in other words, whether or not a cancel command for constant speed travel control has been input from the driver. It is determined whether or not the vehicle is on, that is, whether or not a brake operation has been performed by the driver.
[0083]
When the result in S102 is negative, the program proceeds to S104, in which it is determined whether or not the set switch 100 is turned on, that is, whether or not a constant speed travel command and a set vehicle speed have been input from the driver.
[0084]
When the result in S104 is affirmative, the program proceeds to S106, in which the set vehicle speed (target vehicle speed VD) input via the set switch 100 is detected and stored. At this time, it is determined whether or not any one of far, middle, and near is input (set) as the target inter-vehicle distance from the preceding vehicle via the inter-vehicle switch 106. Remember.
[0085]
Next, in S108, it is determined from the output of the radar output processing ECU 70 whether an obstacle (preceding vehicle) exists. The ACC ECU 110 predicts the predicted route of the vehicle 10 from the yaw rate sensor 82 when determining the presence or absence of an obstacle, and determines whether an obstacle is detected within a predetermined range centered on the predicted route. This prevents misidentification of adjacent lanes (lanes) or structures outside the lane.
[0086]
When the result in S108 is negative, the program proceeds to S110, and normal constant speed traveling control is executed. That is, the throttle actuator 120 and / or the brake actuator 122 are operated using a PID control law or the like according to the deviation between the set vehicle speed (target vehicle speed) VD and the detected vehicle speed V.
[0087]
On the other hand, when the result in S108 is affirmative, the process proceeds to S112, where it is determined whether or not a deceleration command is transmitted from the SAS ECU 74. When the result is affirmative, the process proceeds to S114, and the brake actuator 122 is operated to operate the vehicle 10 (own vehicle). Decelerate. The deceleration at this time is about 0.05 G to 0.2 G (maximum 0.2 G), which is a value used during normal operation.
[0088]
Next, in S116, the bit of the flag FD is set to 1. Setting the bit of this flag to 1 means that a deceleration operation has been performed.
[0089]
On the other hand, when the result in S112 is negative, the process proceeds to S118, where it is determined whether or not the flag FD bit is set to 1. When the result is affirmative, the process proceeds to S120, where deceleration is canceled, that is, the vehicle speed V is increased. Let In this way, for example, since it is decelerated whenever it is determined that a white line up to 30 m ahead cannot be detected, the deceleration is performed gradually, and the driver does not feel uncomfortable.
[0090]
Then, when the deceleration command from the SAS ECU 74 is lost, the determination in S112 is denied, and the process proceeds to S120 via S118 to cancel the deceleration, but at this time, for example, whether a white line can be detected up to 40m or more ahead. It is determined whether or not the vehicle is decelerated only when the result is affirmative, thereby preventing the occurrence of control hunting. Next, in S122, the bit of the flag FD is set to 0. This means that deceleration has been cancelled.
[0091]
Further, in the deceleration operation in S114, it is determined whether or not the vehicle 10 is traveling on the highway through the navigation device 88 described above, and when the result is affirmative, the vehicle is decelerated so as not to fall below the legal minimum vehicle speed of 50 km / h. To do.
[0092]
Next, in S124, the preceding vehicle following (constant speed) traveling control is performed. The same applies when the result in S118 is negative.
[0093]
In the preceding vehicle following (constant speed) traveling control, the distance (relative distance) of the obstacle to the own vehicle (vehicle 10) calculated by the radar output processing ECU 70, its change, the vehicle V of the own vehicle, and the acceleration of the own vehicle. The speed and acceleration of the obstacle are calculated based on (calculated from the difference value or differential value of the vehicle speed V), and when the obstacle is a moving object, it is determined as a preceding vehicle, and the calculated parameters and detected yaw rate, etc. The vehicle is controlled to follow the preceding vehicle while operating the throttle actuator 120 and / or the brake actuator 122 so as to maintain the set inter-vehicle distance based on the predicted vehicle trajectory.
[0094]
If the result in S100 or S102 is affirmative, the subsequent processing is skipped. If the result in S104 is negative, the process proceeds to S126, in which whether or not the resume switch 102 is turned on, that is, constant speed travel control from the driver. It is determined whether or not a restart command is input.
[0095]
When the result in S126 is negative, the subsequent processing is skipped. When the result is affirmative, the process proceeds to S128, the stored set (target) vehicle speed VD and the set inter-vehicle distance are read, and the process proceeds to S108.
[0096]
As described above, the device according to this embodiment is configured to continue the lane keeping steering assist control while decelerating the vehicle when the white line is not detected up to the front gazing point. That is, since the lane keeping steering assist control is not repeatedly stopped and restarted, comfort is not reduced.
[0097]
As described above, in this embodiment, in the vehicle steering control device including the actuator (electric motor 38) that steers the steering wheel (front wheel 32) of the vehicle 10, the imaging means (CCD camera) for imaging the front of the vehicle. 64), a travel path detecting means (image processing ECU 66) for detecting a travel path based on the image information obtained by the imaging means, and a steering assist amount for causing the vehicle to travel along the detected travel path In the vehicle steering control device, comprising: steering assist control means (SAS ECU 74, S10 to S38) for calculating (steering assist torque TLK) and drivingly controlling the actuator based on the calculated steering assist amount. The steering assist control means includes a deceleration means (brake actuator 122) for decelerating When serial travel path detecting means can not detect the traveling path, and said speed reduction means is operated to be allowed (S10, S112, S114) as constituting decelerating the vehicle.
[0098]
Further, in the vehicle steering control device provided with an actuator (electric motor 38) for turning the steering wheel (front wheel 32) of the vehicle 10, an imaging means (CCD camera 64) for imaging the front of the vehicle is obtained by the imaging means. A travel path detection means (image processing ECU 66) for detecting a travel path based on the obtained image information, and a steering assist amount (steering assist torque TLK) for causing the vehicle to travel along the detected travel path. In a vehicle steering control device including steering assist control means (SAS ECU 74, S10 to S38) for driving and controlling the actuator based on the calculated steering assist amount, a preceding vehicle traveling in front of the vehicle is provided. Follow-up running control means (ACC ECU 110, S100 to S128) for following running is provided, and the steering assist The control unit is configured to operate the follow-up travel control unit to decelerate the vehicle when the travel path detection unit cannot detect the travel path (S10, S112, S114).
[0099]
In the above description, torque is used as the steering assist amount, but a steering angle may be used.
[0100]
The lane keeping steering assist control is not limited to the one disclosed, and for example, a technique described in Japanese Patent Application Laid-Open No. 11-78948 may be used. Moreover, in the above, although the vehicle turning behavior was calculated | required from the yaw rate, you may use a steering angle.
[0101]
Furthermore, in the preceding vehicle following traveling control, the distance from the preceding vehicle is set by the distance, but it may be set by time.
[0102]
Furthermore, although EPS ECU76 calculated the assist torque TPS for power steering, SAS ECU74 may perform it.
[0103]
In the above-described embodiment, the laser radar or the like may be, for example, a millimeter wave radar other than the disclosed configuration, and the other sensors are also the same. Moreover, as long as the required detection value is obtained also in those arrangement positions, they may be arranged anywhere.
[0104]
【The invention's effect】
  According to claim 1, when the steering assist control means cannot detect the travel path,And when it is determined by the navigation device that the vehicle is traveling on the highway,Activating the deceleration meansKeep the vehicle below the prescribed speedSince it was configured to decelerate, in other words,Keep the vehicle below the prescribed speedSince the steering assist control is continued while decelerating, even when the white line cannot be detected when the lane keeping steering assist control is executed, the lane keeping steering assist control is repeatedly stopped and restarted. Can be avoided to prevent a decrease in comfort.
[0105]
  Claim2If the steering assist control means cannot detect the travel path,And when it is determined by the navigation device that the vehicle is traveling on the highway,Activate the tracking control meansKeep the vehicle below the prescribed speedSince it was configured to decelerate, in other words,Keep the vehicle below the prescribed speedSince the steering assist control is continued while decelerating, the lane keeping steering assist control is stopped and resumed even when the white line cannot be detected when the lane keeping steering assist control and the preceding vehicle following running control are executed together. It is possible to prevent the comfort from being reduced by avoiding the repetition of.
[Brief description of the drawings]
FIG. 1 is a schematic view showing the entirety of a vehicle steering control apparatus according to the present invention.
2 is an overall schematic view similar to FIG. 1, showing the apparatus of FIG. 1 with a focus on the steering system.
FIG. 3 is a flowchart showing a lane keeping steering assist control operation in the operation of the apparatus of FIG. 1;
4 is a block diagram schematically showing lane keeping steering assist control and the like in the flow chart of FIG. 3. FIG.
FIG. 5 is an explanatory diagram for explaining lane keeping steering assist control shown in the block diagram of FIG. 4;
6 is an explanatory graph showing steering assist torque characteristics determined (calculated) by the SAS ECU and the EPS ECU shown in the block diagram of FIG. 4;
7 is an explanatory top view of a travel path showing a white line detection operation of the apparatus of FIG. 1. FIG.
FIG. 8 is a flowchart showing a preceding vehicle following (constant speed) traveling control operation in the operation of the apparatus of FIG. 1;
[Explanation of symbols]
10 Vehicle
14 Steering wheel
32 Front wheel (steering wheel)
38 Electric motor (actuator)
42 Torque sensor
44 Rudder angle sensor
46, 50 Wheel speed sensor
64 CCD camera (imaging means)
66 Image processing ECU (travel path detection means)
68 Laser radar
70 Radar output processing ECU
74 First electronic control unit (SAS ECU)
76 Second electronic control unit (EPS ECU)
110 Third electronic control unit (ACC ECU)
120 Throttle actuator
122 Brake actuator (deceleration means)
200,202 preceding car
300 white line

Claims (4)

A vehicle steering control device including an actuator for turning a steering wheel of a vehicle,
a. Imaging means for imaging the front of the vehicle;
b. A road detection unit that detects a road based on image information obtained by the imaging unit;
c . Deceleration means for decelerating the vehicle;
and
d . Steering for calculating a steering assist amount for causing the vehicle to travel along the detected traveling path, driving the actuator based on the calculated steering assist amount, and controlling the operation of the deceleration means Assist control means,
In a vehicle steering control device comprising:
e . Navigation device,
And the steering assist control means when the travel path detection means cannot detect the travel path and when the navigation device determines that the vehicle is traveling on a highway, the deceleration means The vehicle steering control device is characterized in that the vehicle is decelerated so as not to fall below a predetermined speed by actuating. A vehicle steering control device including an actuator for turning a steering wheel of a vehicle,
a. Imaging means for imaging the front of the vehicle;
b. A road detection unit that detects a road based on image information obtained by the imaging unit;
c . Follow-up running control means for running following the preceding vehicle running in front of the vehicle,
and
d . A steering assist amount for driving the vehicle along the detected travel path is calculated, and the actuator is driven and controlled based on the calculated steering assist amount, and the operation of the follow-up travel control means is controlled. steering assist control means for,
In a vehicle steering control device comprising:
e . Navigation device,
And the steering assist control means, when the travel path detection means cannot detect the travel path and when the navigation device determines that the vehicle is traveling on an expressway, A vehicle steering control device characterized by operating a control means to decelerate the vehicle so as not to fall below a predetermined speed. A vehicle steering control device including an actuator for turning a steering wheel of a vehicle,
a. Imaging means for imaging the front of the vehicle;
b. A road detection unit that detects a road based on image information obtained by the imaging unit;
c . Deceleration means for decelerating the vehicle;
and
d . Steering for calculating a steering assist amount for causing the vehicle to travel along the detected traveling path, driving the actuator based on the calculated steering assist amount, and controlling the operation of the deceleration means Assist control means,
In a vehicle steering control device comprising:
e . Navigation device,
And the steering assist control means when the travel path detection means cannot detect the travel path and when the navigation device determines that the vehicle is traveling on a highway, the deceleration means the is actuated to decelerate the vehicle so as not to fall below a predetermined speed Rutotomoni, steering the vehicle, characterized in that to release the deceleration of the vehicle based on a detection result of the travel path by the travel path detecting means Control device. A vehicle steering control device including an actuator for turning a steering wheel of a vehicle,
a. Imaging means for imaging the front of the vehicle;
b. A road detection unit that detects a road based on image information obtained by the imaging unit;
c . Follow-up running control means for running following the preceding vehicle running in front of the vehicle,
and
d . A steering assist amount for driving the vehicle along the detected travel path is calculated, and the actuator is driven and controlled based on the calculated steering assist amount, and the operation of the follow-up travel control means is controlled. steering assist control means for,
In a vehicle steering control device comprising:
e . Navigation device,
And the steering assist control means, when the travel path detection means cannot detect the travel path and when the navigation device determines that the vehicle is traveling on an expressway, the control means is operated to decelerate the vehicle so as not to fall below a predetermined speed Rutotomoni, vehicle and cancels the deceleration of the vehicle based on a detection result of the travel path by the travel path detecting means Steering control device.

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