JP2014088050A - Lane deviation prevention system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lane deviation prevention system that prevents a vehicle from deviating from a running lane, and enables appropriate steering even when a steering characteristic differs between a leftward steering operation and rightward steering operation despite a simple and inexpensive arrangement.SOLUTION: In a lane deviation prevention system that prevents a vehicle from deviating from a running lane by driving an actuator so as to autonomously operate a steering system of the vehicle, a driving quantity for the actuator is corrected in order to nullify a difference between an actual turning angle of tires derived from a rightward steering operation and an actual turning angle thereof derived from a leftward steering operation.

Description

  The present invention relates to a technique for automatically controlling an automobile so as not to deviate from a driving lane.

  There has been proposed a technique for automatically controlling a steering device of a vehicle so that the vehicle does not deviate from the traveling lane while the vehicle is traveling regardless of the driver's intention. For example, the cause of such a lane departure is assumed to be driver's carelessness, alertness or drowsiness, and even road swell.

For example, Patent Literature 1 describes a lane keeping assist device that improves a driver's steering feeling by assisting a steering force when a vehicle is about to deviate from a lane.
The auxiliary torque determining means uses a vehicle position, a lane center positioning means, a calculation means for calculating a lateral deviation from a desired position with respect to the center, and a power source for supplying auxiliary torque. The auxiliary torque from is determined. The auxiliary torque determining means is configured to decrease the auxiliary torque when the lateral shift is reduced by the driver's steering operation.

  Further, for example, Patent Document 2 relates to an operation control method and system for lane maintenance assistance for a vehicle, a step of supplying vehicle-related information, a step of supplying environment-related information, a vehicle-related information, and an environment-related information. A step of predicting a future track of the vehicle based on the vehicle-related information and the environment-related information, a step of estimating a desired lane position and / or guidance force of the vehicle, a future track and a desired lane A step of comparing the position, a step of determining whether or not to supply the steering force to the steering device, and a case where the guidance force is supplied to the steering device, the hierarchical ordered set describing the predetermined driving behavior of the vehicle. Determining the magnitude of the guide force based on the step, adjusting the magnitude of the guide force in accordance with the direction in which the vehicle is moving, There technology to include a step of activating one or more actuators for supplying the guiding force which is adjusted to the steering system is described.

US Patent Application Publication No. 2006/047390 JP 2010-536632 A

  According to the techniques described in Patent Document 1 and Patent Document 2, when the vehicle is likely to deviate from the traveling lane while traveling, the steering device is driven by the control device in a route different from the operation of the driver. Such a deviation can be avoided by operating the (steering device). However, in an actual steering device, the steering characteristics differ between the left and right due to factors such as different lengths of the left and right link mechanisms. There is a fact that it is difficult to perform smooth and appropriate control.

  The present invention has been made in view of such circumstances, and has a simple and low-cost configuration, and when the vehicle is likely to deviate from the traveling lane while traveling, the actuator is controlled by a route different from the operation of the driver. In the lane departure prevention system in which the vehicle does not deviate from the driving lane by automatically operating the steering device (steering device) by driving the vehicle, there is a difference in the steering characteristics (steering characteristics) between the left and right of the steering operation. Another object of the present invention is to provide a lane departure prevention system that can be steered appropriately.

For this reason, the present invention
A lane that prevents the vehicle from deviating from the driving lane by driving the actuator and automatically operating the steering device of the vehicle by a route different from the driver's operation when the vehicle is likely to deviate from the driving lane while driving. A departure prevention system,
The drive amount for the actuator is corrected so as to eliminate the difference in actual tire turning angle between the steering operation in the right direction and the steering operation in the left direction.

  In the present invention, the drive amount for the actuator may be corrected based on a ratio between a steering operation amount and an actual tire turning angle.

  In the present invention, the vehicle steering device converts the rotation of the steering wheel into a linear motion of the drag link, and a knuckle arm coupled to the drag link by the linear motion of the drag link, and a tie rod to the knuckle arm. It can be characterized by having a configuration in which the knuckle arm on the opposite side coupled via the steering is interlocked.

  According to the present invention, in a simple and low-cost configuration, when the vehicle is likely to deviate from the driving lane while traveling, the actuator is driven by the control device in a route different from the driver's operation, and the steering device ( In a lane departure prevention system in which the vehicle does not deviate from the driving lane by automatically operating the steering device), even if there is a difference in steering characteristics (steering characteristics) between the left and right of the steering operation, steering is appropriately performed It is possible to provide a lane departure prevention system capable of

1 is a perspective view illustrating an example of a steering device to which a lane departure prevention system according to an embodiment of the present invention is applied. It is an example of the flowchart explaining the automatic steering control performed in the lane departure prevention system which concerns on embodiment same as the above. Steering gain map (steering (steering wheel) steering angle (horizontal axis) used for automatic steering control performed in the lane departure prevention system according to the embodiment described above, and an actual steering angle with respect to the steering (steering wheel) steering angle (actual tire 2 is a diagram showing an example of the relationship between the ratio (vertical angle) and the cutting angle). It is a block diagram which shows schematic structure of the lane departure prevention system which concerns on embodiment same as the above.

  Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. The present invention is not limited to the embodiments described below.

  Here, as described above, in the technique of automatically operating the steering device (steering device) with an actuator such as a motor, a difference occurs in the tire turning angle between the left and right steering operations (steering operations), and the yaw rate (of the automobile) The speed at which the rotation angle in the turning direction changes) differs between left and right steering, and there is a risk that smooth control cannot be performed, such as giving a sense of discomfort to the driver and the like.

  Possible causes of steering variations on the left and right are that the rigidity of the steering mechanism is insufficient and the length of each link of the link mechanism is long in large vehicles such as trucks and buses.

  Further, in the steering apparatus (steering apparatus) as shown in FIG. 1, a steering gear box 20 that converts the rotation of the steering wheel 10 into a reciprocating linear motion of a drag link 30 and a right side A knuckle arm 40A that steers the tire, a knuckle arm 40B that steers the left tire, and a tie rod 50 that connects the knuckle arm 40A and the tie rod 50 to link them are provided, and the knuckle arm 40A is driven to swing by the drag link 30. Thus, the left and right tires 60A, 60B are configured to be steered in conjunction with each other. However, the drag link 30 has an offset portion 30A due to the mounting layout on the vehicle, and the offset portion 30A. However, it is considered that the steering characteristics vary from side to side. It is.

  When the steering wheel 10 is operated clockwise (right turn), the drag link 30 is relatively deformed (elongated) due to the steering force and the tire reaction force due to the steering force and the tire reaction force. When 10 is operated counterclockwise (left turn), it is considered that the drag link 30 has a small deformation (shrinkage) due to a compressive force, resulting in variations in steering characteristics on the left and right. It is done.

  Such differences in steering characteristics between the left and right can be resolved by changing the structure of the link mechanism, but there is a fact that changing the structure of the link mechanism is not easy due to the mounting layout on the vehicle. .

  For this reason, the lane departure prevention system according to the present embodiment can be appropriately steered by the following method even when the steering characteristic (steering characteristic) is different between the left and right in the steering operation. I made it.

That is, the lane departure prevention system according to the present embodiment is
(1) A yaw rate sensor (a sensor that detects a speed at which the rotation angle of the vehicle changes in the turning direction) 100, a vehicle speed sensor 200, and a steering sensor (steering amount (angle) sensor) 300 that are currently mounted on the vehicle. , Is used. As shown in FIG. 4, each detection output (acquisition information acquired by the sensor) is input to an electronic control unit (ECU) 400 that controls the lane departure prevention system.

  (2) From the detection output of the vehicle speed sensor 200, the actual vehicle speed (vehicle traveling speed), the wheelbase distance (set according to the vehicle specifications), and the yaw rate detected by the yaw rate sensor 100 are used to determine the actual steering wheel. The cutting angle (actual steering angle) is obtained by calculation processing.

  (3) Based on the detection output of the steering sensor 300, a steering angle by a steering (handle) operation is acquired.

  (4) In the above (2) and (3), calculation processing is performed at the time of normal traveling for each of the steering in the left and right directions, and the variation (difference) between the left and right is acquired, and the actual steering angle and the steering steering angle are obtained. The ratio is obtained and mapped for each steering angle. For example, a map as shown in FIG. 3 is created.

  (5) When there is a possibility of lane departure, an actuator 70 such as an electric motor as shown in FIG. 1 is driven by a route different from the driver's steering operation so that the vehicle does not depart from the lane. Automatic steering control is performed in which the gearbox 20 is driven (assisted) to automatically control (steer) the traveling direction (tire cut angle) of the vehicle. At this time, steering in the right direction and in the left direction are performed. The driving amount (steering amount) applied to the actuator 70 is corrected so that the variation in the steering characteristic between the two steering operations can be eliminated.

  That is, referring to the map (see FIG. 3 etc.) acquired in the above (4), the automatic steering control from the lane so that the actual steering angle (actual tire turning angle) is substantially the same between the left and right. After correcting the “steering amount (driving amount) applied to the actuator 70” set according to the degree of deviation, etc., control is performed so that a driving signal corresponding to the corrected steering amount is applied to the actuator 70.

  The determination as to whether or not there is a possibility of lane departure is performed based on image information acquired from, for example, a CCD camera, so as to eliminate the lateral deviation (lateral deviation) from the target course. Steering control for running the vehicle while automatically steering can be performed.

  Here, the control performed by the lane departure prevention system according to the present embodiment will be described more specifically according to the control flowchart of FIG. In addition, the control flowchart of FIG. 2 is performed for every predetermined time.

As shown in FIG.
In step (denoted as S in the figure, the same applies hereinafter) 1, whether or not there is a possibility of lane departure is determined based on image information acquired from the CCD camera or the like. If there is no risk of lane departure and normal travel is being performed, the process proceeds to step 10 as OK, and this control is turned off and the process ends.
If there is a risk of lane departure, the process proceeds to step 2 as NG.

In step 2, the presence or absence of a driver (driver) operation (steering operation, accelerator pedal operation, brake pedal operation, operation of various other switches, etc.) is confirmed.
If the driver is performing any operation, a YES determination is made and the process proceeds to step 11 where various driving information and its history are analyzed, and characteristics related to driver's carelessness, alertness, sleepiness, etc. Based on the amount or the like, the state of the driver (driver) is estimated (determined).

  If it is in a normal state, an OK determination is made, the process proceeds to step 12, this control is turned off, and the process ends.

  On the other hand, if it is determined that there is a risk of carelessness, alertness, drowsiness, etc. on the driver, an NG determination is made and the process proceeds to step 3.

  In step 3, a process for shifting to the steering control mode is performed. That is, in order to prevent the vehicle from deviating from the lane, the steering gear box 20 is controlled by driving the actuator 70 such as an electric motor as shown in FIG. A process of shifting to a steering control mode in which is automatically operated is performed.

  First, in step 4, a lane departure warning is issued in order to warn the driver of the possibility of lane departure (a warning or the like is lit or blinked, a warning sound or a warning announcement is issued).

  In step 5, in response to the lane departure warning in step 4, whether or not the driver (driver) has performed any operation (steering operation, accelerator pedal operation, brake pedal operation, operation of various other switches). Check.

  In the case of YES (Yes), the process proceeds to Step 13 where various driving information and its history are analyzed, and based on the feature amount related to the driver's carelessness, alertness, drowsiness, etc., the driver ( (Driver) state is estimated (determined).

  If it can be determined that the state has returned to the normal state, an OK determination is made, the process proceeds to step 14, the present control is turned off, and the process ends.

  On the other hand, in the case of NO (none), there is a possibility that carelessness, alertness, drowsiness, etc. may occur in the driver, and thus the process proceeds to step 6.

  In step 6, the amount of lateral deviation (lateral deviation) from the target course is acquired.

  In step 7, a target yaw rate is set. The target yaw rate is estimated by estimating the vehicle state (such as the passenger's boarding position and number of passengers in the case of buses, and the loading state of luggage in the case of trucks) from the weight estimation and center of gravity estimation during normal driving. It can be set as the structure set to an appropriate target value according to it.

  In step 8, a target steering angle is set. A target steering amount (target steering angle) is set from the magnitude of the lateral deviation and the target yaw rate so that optimum steering is realized.

  In the present embodiment, at this time, the steering amount given to the actuator 70 so as to eliminate the variation in the left and right steering characteristics, the steering characteristic variation existing between the steering in the right direction and the steering in the left direction. Correct (drive amount).

Specifically, the target steering amount (target steering angle) is set with reference to a map as shown in FIG.
That is, in the case of steering to the right, when the target steering amount (target steering steering amount) of “200” is given as the steering amount to the right (steering steering amount) in the map of FIG. Therefore, in order to actually obtain the target yaw rate, it is actually necessary to give a steering amount about 2.0 times the target steering amount (target steering amount).

  On the other hand, in the case of steering to the left, when a target steering amount (target steering steering amount) of “200” is given as the steering amount to the left (steering steering amount) in the map of FIG. In order to actually obtain the target yaw rate, it is actually necessary to give a steering amount of about 0.7 times the target steering amount.

  For this reason, in the present embodiment, the target steering amount (target steering angle) is corrected with reference to the map of FIG. 3 with respect to the target steering amount (target steering angle) set from the target yaw rate, The corrected value is set as the final target steering amount (target steering angle).

In step 9, based on the final target steering amount (target steering angle), an actuator 70 such as an electric motor is driven to drive the steering gear box 20 to execute automatic steering control for automatically steering the vehicle. To do.
At this time, the driver is warned that automatic steering control is being executed by lighting or blinking a warning or the like, or issuing an alarm sound or a warning announcement.

  As described above, according to the present embodiment, when there is a risk of lane departure, the actuator 70 such as an electric motor is driven by a route different from the driver's steering operation so that the vehicle does not depart from the lane. Then, the steering gear box 20 is driven (assisted) to execute automatic steering control for automatically controlling (steering) the traveling direction of the vehicle (tire turning angle). The drive amount (steering amount) applied to the actuator 70 is corrected so that the variation in steering characteristics between the leftward steering and the leftward steering can be eliminated. As a result, sudden steering or excessively slow steering in automatic steering control can be suppressed, so that a sense of incongruity can be eliminated and safety can be improved. It can become.

  That is, according to the present embodiment, when the vehicle is likely to deviate from the travel lane while traveling, the actuator is driven by the control device in a route different from the driver's operation, even though the configuration is simple and low-cost. In a lane departure prevention system in which the vehicle does not deviate from the driving lane by automatically operating the steering device (steering device), even if there is a difference in steering characteristics (steering characteristics) between the left and right of the steering operation It is possible to provide a lane departure prevention system that can be steered.

  In the above-described embodiment, the description has been given of the steering device for a large vehicle such as a bus and a truck. However, the present invention is not limited to this, and the present invention can be similarly applied to an ordinary automobile. It is something that can be done.

  The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the present invention.

10 Steering wheel (handle)
20 Steering gear box 30 Drag link (pull bar)
30A offset part 40A knuckle arm (right)
40B Knuckle arm (left)
50 Tie Rod 60A Tire (Right)
60B tire (left)
100 Yaw rate sensor 200 Vehicle speed sensor 300 Steering sensor (steering angle sensor)
400 Electronic control unit (ECU)

Claims (3)

A lane that prevents the vehicle from deviating from the driving lane by driving the actuator and automatically operating the steering device of the vehicle by a route different from the driver's operation when the vehicle is likely to deviate from the driving lane while driving. A departure prevention system,
A lane departure prevention system for correcting a driving amount for the actuator so as to eliminate a difference in actual tire turning angle between a steering operation in the right direction and a steering operation in the left direction. .   The lane departure prevention system according to claim 1, wherein the correction of the driving amount for the actuator is performed based on a ratio between a steering operation amount and an actual tire turning angle.   The vehicle steering device converts the rotation of the steering wheel into a linear motion of the drag link, and is connected to the knuckle arm by a linear motion of the drag link and the knuckle arm via a tie rod. The lane departure prevention system according to claim 1, wherein the knuckle arm on the opposite side is steered while being interlocked.

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