JP5401961B2 - Steering support device - Google Patents

Description

  The present invention relates to a steering assist device, and more particularly to a steering assist device for preventing lane departure that prevents a traveling vehicle from departing from a lane.

Conventionally, in order to prevent a vehicle traveling on a road on which a lane is drawn from deviating from the lane, torque application means for applying auxiliary steering torque in addition to steering torque applied by a driver's steering operation is provided. A steering assist device is known. Further, as this type of steering assist device, when the direction of the auxiliary steering torque applied by the torque applying unit and the steering torque by the driver's steering operation are different, the auxiliary steering torque applied by the torque applying unit is reduced. There are some (see, for example, Patent Document 1). According to this steering assist device, it is possible to perform the steering assist control adapted to the steering wheel of the driver.
JP 2007-038697 A

  However, in the steering assist device disclosed in Patent Document 1, when the direction of the auxiliary steering torque applied by the torque applying unit and the steering torque by the driver's steering operation are different, the torque applying unit uniformly applies the steering assist device. The auxiliary steering torque is reduced. Therefore, depending on the surrounding environment of the vehicle, the auxiliary steering torque may or may not be reduced unlike the driver's intention, which may cause the driver to feel uncomfortable. .

  Accordingly, an object of the present invention is to provide a steering support device capable of performing steering support control adapted to steering wheel steering while reducing an uncomfortable feeling given to the driver by applying an auxiliary steering torque according to the driver's intention. It is to provide.

The steering assist device according to the present invention that has solved the above problems includes a torque applying unit that applies an auxiliary steering torque to the steering mechanism so that the vehicle travels along the travel path based on an image obtained by imaging the travel path ahead of the vehicle. And a steering torque suppression unit that suppresses the auxiliary steering torque to be applied to the steering mechanism when the difference between the steering amount by the torque applying unit and the steering amount by the steering operation of the vehicle exceeds a predetermined threshold value. A torque suppression control expectation situation determination means for determining a torque suppression control expectation situation, which is a situation in which a driver of the vehicle expects the suppression of the auxiliary steering torque by the torque suppression means. when the condition determining means determines that the torque suppression control expected conditions, to reduce the predetermined threshold value, a steering amount is the steering force and steering time, a predetermined threshold Steering time threshold to the steering force threshold and the steering time for steering force, characterized in that it is configured as.

  In the steering assist device according to the present invention, an assist state to be applied to the steering mechanism is determined based on the determination result of the torque suppression control expectation state in which the driver of the vehicle expects the suppression of the auxiliary steering torque by the torque suppression unit. The threshold value for determining to suppress the steering torque is adjusted. For this reason, it can be adjusted whether the driver | operator of a vehicle suppresses the auxiliary steering torque provided to a steering mechanism according to the condition where suppression of the auxiliary steering torque by a torque suppression means is expected. Therefore, by providing the auxiliary steering torque according to the driver's intention, it is possible to perform the steering assist control adapted to the steering wheel while reducing the uncomfortable feeling given to the driver.

  As described above, when the torque suppression control expectation situation determination unit determines that the torque suppression control expectation situation is satisfied, the vehicle driver can suppress the auxiliary steering torque by the torque suppression unit by reducing the predetermined threshold value. It is possible to suppress the auxiliary steering torque that is applied to the steering mechanism when the situation is expected.

  As the predetermined threshold value for the difference between the steering amount by the torque applying means and the steering amount by the steering operation of the vehicle, a steering force threshold value for the steering force and a steering time threshold value for the steering time are preferably used. it can.

  At this time, the predetermined threshold value can be reduced by reducing the steering force threshold value, and the predetermined threshold value can be reduced by shortening the steering time threshold value.

  As described above, the predetermined threshold value is reduced by decreasing the steering force threshold value, or the predetermined threshold value is decreased by decreasing the steering time threshold value. Can be adjusted.

  Further, when the torque suppression control expectation situation determination unit determines that the torque suppression control expectation situation is not satisfied, the predetermined threshold value can be increased.

  As described above, when the torque suppression control expectation situation determination means determines that the torque suppression control expectation situation is not satisfied, the vehicle driver can suppress the auxiliary steering torque by the torque suppression means by increasing the predetermined threshold value. It is possible to prevent the auxiliary steering torque to be applied to the steering mechanism from being suppressed in an unexpected situation.

  Here, the torque suppression control expected situation determination means can determine that it is not the torque suppression control expectation situation when the driver of the vehicle is in a look-aside state, and when the driver of the vehicle is in a dozing state, It can also be determined that the torque suppression control is not expected.

  When the driver of the vehicle is in a state of looking aside, it can be determined that the situation is not expected to be torque suppression control. When the driver of the vehicle is in a dozing state, the driver is expecting torque suppression control. It is not considered. For this reason, when the driver of the vehicle is looking aside or in a dozing state, it is determined that the torque suppression control is expected, thereby providing auxiliary steering torque that does not contradict the driver's intention. Can do.

  In addition, there is provided a determination duration measuring means for measuring a determination duration that is a time determined to be the torque suppression control expected situation by the torque suppression control expectation situation judging means, and the measurement result of the judgment duration measuring means is included in the measurement result. Based on this, it is possible to adopt a mode in which the amount of suppression of the auxiliary steering torque by the steering torque suppression means is adjusted.

  In this way, by adjusting the amount of suppression of the auxiliary steering torque by the steering torque suppression unit based on the measurement result of the determination duration time measuring unit, the amount of suppression of the auxiliary steering torque is changed according to the duration of the torque suppression control. Is done. For this reason, the uncomfortable feeling given to the driver can be further reduced.

  At this time, according to the length of the determination continuation time, the amount of suppression of the auxiliary steering torque applied to the steering mechanism by the steering torque suppression unit can be increased. Furthermore, the amount of suppression of the auxiliary steering torque applied to the steering mechanism by the steering torque suppression means can be increased according to the integrated value of the steering torque by the steering operation during the determination duration time.

  In this way, by increasing the amount of suppression of the auxiliary steering torque applied to the steering mechanism by the steering torque suppression means according to the length of the determination duration and the integrated value of the steering torque by the steering operation during the determination duration, The control according to the driver's habit can be performed, and the uncomfortable feeling given to the driver can be suitably reduced.

  According to the steering assist device according to the present invention, by providing an auxiliary steering torque according to the driver's intention, it is possible to perform the steering assist control adapted to the steering wheel while reducing the uncomfortable feeling given to the driver.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted. FIG. 1 is a block diagram of a steering assist device according to an embodiment of the present invention.

  As shown in FIG. 1, the steering assist device 1 according to the present embodiment includes a departure prevention assist ECU 10. The departure prevention assisting ECU 10 is connected to a vehicle speed detection means 11, a steering torque detection means 12, a white line recognition camera 13, a brake switch 14, a blinker switch 15, a main switch 16, and a front recognition radar 17. Further, the departure prevention assisting ECU 10 is connected with a steering torque applying means 2, an alarm buzzer 3, and a meter 4 as torque applying means.

  The departure prevention assisting ECU 10 determines whether or not the vehicle departs from the lane based on information output from the vehicle speed detection means 11, the steering torque detection means 12, the white line recognition camera 13, and the like. As a result, when it is determined that the vehicle departs from the lane after a predetermined time, a predetermined signal is output to the steering torque applying means 2, the alarm buzzer 3, and the like. The departure prevention assist ECU 10 constitutes a steering torque suppression means.

  Further, when the departure prevention assisting ECU 10 performs lane departure determination, does the steering torque detected by the steering torque detecting means 12 interfere with the control torque that is the auxiliary steering torque applied by the steering torque applying means 2? Interference judgment of whether or not. As a result of the interference determination, when it is determined that the steering torque and the control torque are interfering with each other, the target control torque that is the target value of the control torque is reduced. In the interference determination, it is determined that interference occurs when the steering torque and the control torque each exceed a predetermined threshold value. The departure prevention assisting ECU 10 determines the expected torque suppression control situation according to the situation around the vehicle, etc., and adjusts the threshold when performing the interference determination according to the expected torque suppression control situation. The departure prevention assist ECU 10 constitutes a relative relationship detection means and a torque suppression control expectation situation determination means.

  The departure prevention assisting ECU 10 uses the steering torque low threshold value Dd_il, the steering torque standard threshold value Dd_is, the control torque low threshold value Dt_il, the control torque standard threshold value Dt_is, and the establishment determination time as threshold values used for interference determination. The low threshold value To_il and the establishment determination time standard threshold value To_is are stored. Also, as a cancellation threshold value used for interference cancellation determination, a cancellation steering torque low threshold value Dd_ol, a cancellation steering torque standard threshold value Dd_os, a cancellation control torque low threshold value Dt_ol, and a cancellation control torque standard value are used. The threshold value Dt_os, the release establishment determination time low threshold value To_ol, and the release establishment determination time standard threshold value To_os are stored. Further, in order to adjust the threshold value for the interference determination, the relative distance threshold value X_l between the preceding vehicle and the white line and the arrival time threshold value T_l until the vehicle reaches the preceding vehicle are stored. .

  In the departure prevention assisting ECU 10, when the interference determination low threshold flag is ON, the interference determination low threshold is set, and the interference determination is easily established. On the other hand, when the interference determination low threshold flag is OFF, the interference determination standard threshold is set and interference determination is difficult to be established.

  Further, the departure prevention assisting ECU 10 includes an interference determination low threshold flag ON timer that measures the time during which the interference determination low threshold flag is ON. Further, when the duration for which the interference determination low threshold flag is ON exceeds a predetermined duration, the interference determination becomes a predetermined duration for turning off the interference determination low threshold flag. The low threshold flag duration threshold value α is stored. More detailed functions of the departure prevention support ECU 10 will be described later.

  The vehicle speed detection means 11 is attached to the front wheel portion of the vehicle, for example, and detects the vehicle speed when the host vehicle travels. The vehicle speed detection means 11 outputs the detected vehicle speed to the departure prevention assisting ECU 10.

  The steering torque detection means 12 is attached to, for example, a steering rod connected to the steering in the vehicle interior, and detects the steering torque input to the steering by the driver's steering operation. The steering torque detection means 12 outputs the detected steering torque signal to the departure prevention assisting ECU 10.

  The white line recognition camera 13 is disposed, for example, in a position overlooking the outside of the vehicle from the upper part of the windshield in the vehicle interior, and images the situation outside the vehicle as seen through the windshield. The white line recognizing camera 13 outputs the captured outside situation to the departure prevention assisting ECU 10.

  The brake switch 14 is attached to, for example, a brake pedal in the passenger compartment, and detects the operation of the brake pedal by the driver. The brake switch 14 outputs a brake signal to the departure prevention assisting ECU 10 when the driver operates the brake pedal to cause the vehicle to perform a braking operation.

  The blinker switch 15 is attached to, for example, a blinker lever in the passenger compartment, and detects the operation of the blinker by the driver. The winker switch 15 outputs a winker signal to the departure prevention assisting ECU 10 when the driver tries to take out the winker by operating the winker lever.

  The main switch 16 is attached, for example, to a door on the driver's seat side in the passenger compartment. When a driver or the like performs an operation to turn on the main switch 16, the main switch 16 outputs an ON signal to the departure prevention assisting ECU 10. The departure prevention support ECU 10 receives the ON signal and starts departure prevention support.

  The forward recognition radar 17 is a sensor that detects the presence or absence of an obstacle in front of the host vehicle, the direction of an obstacle such as a preceding vehicle (another vehicle) relative to the host vehicle, and the distance between the host vehicle and the obstacle. For example, the forward recognition radar 17 is a millimeter wave radar sensor that transmits and receives millimeter wave signals. The forward recognition radar 17 transmits a millimeter wave signal to a predetermined range in front of the host vehicle, receives a reflected wave signal in which the millimeter wave signal is reflected by the obstacle, and whether there is an obstacle in front of the host vehicle, and The direction of the obstacle with respect to the host vehicle is detected. Further, the forward recognition radar 17 calculates the distance to the obstacle from the millimeter wave signal transmission time and the reflected wave signal reception time. The forward recognition radar 17 transmits a radar signal including obstacle presence / absence information, obstacle direction information, and distance information to the obstacle to the departure prevention assisting ECU 10. The forward recognition radar constitutes other vehicle detection means.

  As the steering torque applying means 2, for example, an electric motor in an electric power steering device connected to a steering rod is used. The steering torque applying means 2 applies a predetermined control torque to the steering rod based on the applied signal output from the departure prevention assisting ECU 10.

  The alarm buzzer 3 is provided, for example, in an instrument panel portion in the passenger compartment, and issues an alarm of a predetermined volume that reaches the driver. The alarm buzzer 3 has a plurality of types of signals, and a predetermined type of alarm is output based on the alarm signal output from the departure prevention assisting ECU 10.

  The meter 4 is provided with a speed meter 21 and a tachometer 22 as shown in FIG. The display portion of the speed meter 21 includes a departure prevention support execution display 23 represented by characters “LKA”, a steering control execution display 24, a white line recognition display 25, a radar cruise display 26, and a radar cruise set speed display 27. Is displayed. These display portions are appropriately displayed based on a display signal output from the departure prevention assisting ECU 10. Specifically, the departure prevention support execution display 23 is lit while the departure prevention support is being performed.

  Next, the operation and action of the steering assist device 1 in this embodiment will be described. FIG. 3 is a flowchart showing a processing procedure of the steering assist device according to the present embodiment, and FIG. 4 is a flowchart showing a procedure of target control torque determination processing. A series of control processes in FIG. 3 are repeatedly executed at a predetermined cycle by the departure prevention assisting ECU 10, for example. In the present embodiment, the target control torque determination process has a feature, but before the description of the target control torque determination process, the processing procedure of the steering assist device will be described.

  As shown in FIG. 3, the steering assist device 1 confirms that the main switch 16 is turned on as a pre-process for starting driving assistance. If the main switch 16 is ON, white line information processing for extracting a white line from an image taken by the white line recognition camera 13 is performed to recognize the white line of the lane in which the vehicle travels (S1).

  After determining whether or not steering assistance is possible, a driver operation determination is performed (S2). The driver's operation determination is made based on a steering torque signal output from the steering torque detection means 12, a brake signal output from the brake switch 14, a winker signal output from the winker switch 15, and the like. When the steering torque signal indicates a predetermined torque amount, it is determined that the driver has operated the steering. When a brake signal is output from the brake switch 14, it is determined that the driver has performed a brake operation. When a winker signal is output from the winker switch 15, it is determined that the driver has performed a blinker operation.

  Following the driver's operation determination, surrounding vehicles are detected (S3). In the detection of the surrounding vehicle, the forward vehicle in front of the periphery of the vehicle is detected based on the millimeter wave signal transmitted from the forward recognition radar 17. Then, based on the steering torque signal transmitted from the steering torque detection means 12, the steering torque input to the steering by the steering operation of the driver is detected (S4). Subsequently, the control torque applied to the steering rod by the steering torque applying means 2 is detected based on the applied signal output to the steering torque applying means 2 (S5). Thereafter, a target control torque determination process is performed using the control torque and the steering torque (S6). The target control torque determination process will be described in detail later.

  When the target control torque determination process is performed, the target control torque is applied to the steering system by the steering torque applying means 2. Then, departure determination processing is performed (S7). When performing the departure determination process, as a departure prevention support, a buzzer sounding process for notifying the driver that the steering assist torque is to be applied is performed (S8). In the lane departure determination process, when it is determined that the vehicle departs from the lane and the steering assist torque is applied by the steering torque application means 2, a warning of a predetermined sound is output from the alarm buzzer 3.

  Further, a buzzer sounding process is performed and an alarm display process is performed (S9). Further, in the lane departure determination process, when the vehicle is determined to depart from the lane and the target control torque is applied by the steering torque applying means 2, the meter 4 displays the departure prevention support execution display 23 and the white line recognition display. Etc. are made. Thereafter, predetermined data output processing is performed (S10). In this way, driving support ends.

  Now, the target control torque determination process will be described. FIG. 4 is a flowchart illustrating a procedure of target control torque determination processing.

  As shown in FIG. 4, in the target control torque determination process, the interference determination low threshold flag is set to a default value of OFF (S11). Next, when a forward vehicle traveling in the adjacent lane is detected in front of the vehicle, a relative distance X between the forward vehicle and the white line and an arrival time T until the vehicle reaches the forward vehicle are calculated. The relative distance X between the preceding vehicle and the white line is calculated based on the position of the white line recognized based on the outside information transmitted from the white line recognition camera 13 and the distance to the preceding vehicle recognized by the front recognition radar 17. . The arrival time T until the vehicle reaches the front vehicle is based on the vehicle speed detected by the vehicle speed detection means 11, the distance from the vehicle recognized by the front recognition radar 17 to the front vehicle, and the speed of the front vehicle. Calculated. Then, whether or not the relative distance X between the preceding vehicle and the white line is equal to or less than the relative distance threshold value X_l and the arrival time T until the vehicle reaches the preceding vehicle is equal to or less than the arrival time threshold value T_l. Judgment is made (S13).

  As a result, there is a condition that the relative distance X between the preceding vehicle and the white line is equal to or less than the relative distance threshold value X_l, and the arrival time T until the vehicle reaches the preceding vehicle is equal to or less than the arrival time threshold value T_l. If it is determined that it is established, the interference determination low threshold flag is turned ON (S13). On the other hand, the condition that the relative distance X between the preceding vehicle and the white line is equal to or less than the relative distance threshold value X_l and the arrival time T until the vehicle reaches the preceding vehicle is equal to or less than the arrival time threshold value T_l. If it is determined that it is not, the process proceeds to step S14 as it is.

  Then, it is determined whether or not the interference determination low threshold flag is ON (S14). As a result, when it is determined that the interference determination low threshold flag is ON, the interference determination low threshold is set as the threshold used for the interference determination (S15). Here, among the interference determination low threshold values, the steering torque threshold value is Dd_i, the steering torque low threshold value Dd_il, the control torque threshold value Dt_i is the control torque low threshold value Dt_il, and the establishment determination time threshold value To_i. The establishment determination time low threshold value To_il is set as follows.

  Of the release threshold values used for interference release determination, the release steering torque threshold value Dd_o is set as the release steering torque low threshold value Dd_ol, and the release control torque threshold value Dt_o is set as the release control torque low threshold value. The release establishment determination time low threshold To_ol is set as the value Dt_ol and the release establishment determination time threshold To_o, respectively. Then, the interference determination low threshold flag ON timer is counted up (S16).

  On the other hand, when it is determined that the interference determination low threshold flag is OFF, the interference determination low threshold is set as the threshold used for the interference determination (S17). Specifically, the steering torque low threshold value Dd_il is set as the steering torque threshold value Dd_i as the interference determination low threshold value set here. Further, the control torque low threshold value Dt_il is set as the control torque low threshold value Dt_i. Further, the establishment determination time threshold value To_il is set as the establishment determination time threshold value To_i. Of the release threshold values used for interference release determination, the release steering torque standard threshold value Dd_os is set as the release steering torque threshold value Dd_o, and the release control torque standard threshold value is set as the release control torque threshold value Dt_o. The release establishment determination time standard threshold value To_os is set as the value Dt_os and the release establishment determination time threshold value To_o, respectively.

  Subsequently, interference determination and control torque reduction processing are performed (S18). In the interference determination, the interference determination is performed by comparing the steering torque detected in step S4 (FIG. 3), the control torque detected in step S5, and the interference determination threshold set in steps S15 and S16. In the interference determination, for example, a case where the interference determination low threshold is set as the interference determination threshold will be described. In this case, the time during which the steering torque Dd is equal to or lower than the steering torque low threshold Dd_il and the control torque Dt is equal to or lower than the control torque low threshold Dt_il exceeds the establishment determination time low threshold To_il. It is determined whether the condition is satisfied. When this condition is satisfied, it is determined that the steering torque and the control torque interfere with each other. If this condition is not satisfied, it is determined that the steering torque and the control torque do not interfere with each other.

  The control torque reduction process is performed according to a determination as to whether the steering torque and the control torque are interfering with each other. Here, when it is determined that the steering torque and the control torque interfere with each other, the target control torque is reduced to a low target control torque. On the other hand, when it is determined that the steering torque and the control torque do not interfere with each other, the target control torque is maintained to be the standard target control torque.

  Further, when the target control torque is set to the low target control torque at the time of the interference determination, the interference cancellation determination is performed as to whether or not to return the target control torque to the standard control torque. In the interference cancellation determination, the cancellation steering torque threshold value Dd_o, the cancellation control torque threshold value Dt_o, and the cancellation establishment determination time threshold value To_o are used. In the interference cancellation determination, the interference cancellation determination is performed by comparing the steering torque detected in step S4 (FIG. 3), the control torque detected in step S5, and the cancellation interference determination threshold set in steps S15 and S16. Do.

  In the interference cancellation determination, for example, a case where the cancellation interference determination low threshold is set as the cancellation interference determination threshold will be described. In this case, the time during which the steering torque Dd exceeds the release steering torque low threshold Dd_ol and the control torque Dt exceeds the release control torque low threshold Dt_ol is set to the release establishment determination time low threshold To_ol. It is determined whether or not the condition of exceeding is satisfied. If this condition is satisfied, it is determined that the interference between the steering torque and the control torque has ended, and the interference determination low threshold flag is turned OFF. If this condition is not satisfied, it is determined that the interference between the steering torque and the control torque has not ended, and the interference determination low threshold flag is kept ON.

  When the interference determination and control torque reduction processing are thus completed, the interference determination low threshold flag is OFF, and the measurement time of the interference determination low threshold flag ON timer is the interference determination low threshold flag duration threshold. It is determined whether it is α or less (S19). As a result, if the interference determination low threshold flag is OFF and the measurement time of the interference determination low threshold flag ON timer is less than or equal to the interference determination low threshold flag duration threshold value α, the step Returning to S13, the process is repeated. On the other hand, the condition that the interference determination low threshold flag is OFF and the measurement time of the interference determination low threshold flag ON timer is less than or equal to the interference determination low threshold flag duration threshold value α is not satisfied. In this case, the interference determination low threshold flag ON timer is reset (S20), and the process is terminated.

  As described above, in the steering assist device according to the present embodiment, the interference determination threshold value at the time of performing the interference determination is adjusted according to the relative relationship with other vehicles traveling around the vehicle. For example, as shown in FIG. 5, in front of the periphery of the vehicle M traveling in the first travel lane L1, a large vehicle M1 that is a forward vehicle travels in the second travel lane L2, and the vehicle M passes the large vehicle M1. May try to overtake. At this time, the driver of the vehicle M often tries to travel a position far from the large vehicle M1, and tends to travel a position far from the white line W.

When performing the interference determination in such a situation, if the interference determination is performed using the steering torque standard threshold value Dd_is as the steering torque threshold value Dd_i, the interference determination is difficult to be established, and the driver is far from the large vehicle M1. Even if it is going to drive the position, the control torque to be guided to the lane side is likely to be generated. As a result, a control torque is generated against the driver's intention, which may increase the sense of discomfort given to the driver or cause hunting. Similarly, when the control torque standard threshold value Dt_is is used as the control torque threshold value Dt_i, or when the establishment determination time standard threshold value To_is is used as the establishment determination time threshold value T_oi, the interference determination is similarly established. It becomes difficult to do.

  In this regard, in the steering assist device according to the present embodiment, as shown in FIG. 6, the relative distance X between the large vehicle M1 and the white line W and the arrival time T from the vehicle M to the large vehicle M1 are respectively the relative distance threshold values. When X_l and the arrival time threshold value T_l are smaller, the steering torque threshold value Dd_i, the control torque threshold value Dt_i, and the establishment determination time threshold value To_i are respectively reduced by the steering torque low threshold value Dd_il and the control torque. The threshold value Dt_il and the establishment determination time low threshold value To_il are used. The arrival time T can be calculated by dividing the distance Y between the vehicle M and the large vehicle M1 by the relative speed ΔV of the large vehicle with respect to the speed of the vehicle M.

  For example, as shown in FIG. 7, it is assumed that the steering torque Dd and the control torque Dt change with time. In this case, when the interference determination threshold is large and the steering torque standard threshold Dd_is, the control torque standard threshold Dt_is, and the establishment determination time standard threshold To_is are used, the intention of the driver of the vehicle M Even if the steering is performed as expected, the interference determination is likely to be established. On the other hand, when the interference determination threshold is small and the steering torque low threshold Dd_il, the control torque low threshold Dt_il, and the establishment determination time low threshold To_il are used as in this embodiment, The interference determination is difficult to be established, and the steering control according to the intention of the driver of the vehicle M can be performed.

  In the steering assist device 1 according to this embodiment, after the interference determination low threshold flag is once set, the interference determination low threshold is maintained until the interference determination low threshold flag duration threshold value α elapses. The value flag is maintained. For this reason, since the situation in which the interference determination threshold value is frequently updated can be prevented, the driver of the vehicle M can be reduced in discomfort based on the fluctuation of the interference determination threshold value.

  Further, in the present embodiment, when setting the interference determination threshold, other vehicles traveling around the vehicle are detected, and the expected state of torque suppression control is determined using the detected relative relationship between the other vehicle and the vehicle. ing. For this reason, since the torque suppression control expected situation can be determined based on the relative relationship between the other vehicle and the vehicle, the torque suppression control expected situation can be appropriately determined.

  Next, a second embodiment of the present invention will be described. In the present embodiment, the expected state of torque suppression control is determined based on obstacles around the vehicle, the driver's arousal level, the situation of looking aside, and the like. FIG. 8 is a block configuration diagram of the steering assist device according to the second embodiment. As shown in FIG. 8, the steering assist device 30 according to the present embodiment includes a car navigation device 31, a surrounding monitoring sensor 32, a wakefulness detection device 33, and a side look detection device 34. It is connected. Other points are the same as those in the first embodiment.

  The car navigation device 31 uses a global positioning system or the like to detect the current position of the host vehicle and to provide various guidance to a travel destination. The car navigation device 31 holds a map information database for displaying a map around the current position of the vehicle on a display. Further, the car navigation device 31 transmits the travel position of the point where the vehicle travels to the departure prevention assisting ECU 10. In addition, the car navigation device 31 transmits lane-related information such as the number of lanes and the lane position at the travel position of the vehicle to the departure prevention assisting ECU 10.

  The periphery monitoring sensor 32 includes a camera provided on the side of the vehicle, and detects an obstacle around the vehicle. The surrounding monitoring sensor 32 transmits an image including the detected surrounding information to the departure prevention assisting ECU 10.

  The arousal level detection device 33 is a sensor that determines whether or not the driver's arousal level is lowered. In the arousal level detection device 33, the periphery of the driver's face is imaged with a camera, an image of the driver's eyes is extracted from the captured image, and whether or not the eyes are closed from the image of the eyes (that is, awakening). Whether or not the degree is lowered). Then, the wakefulness detection device 33 determines the driver's wakefulness based on the closed eye state, and transmits the determined wakefulness to the departure prevention assisting ECU 10. The lower the driver's arousal level (the stronger the drowsiness), the closer the driver is to the eyes and the more asleep.

  The armpit detection device 34 is arranged in an instrument panel in the passenger compartment or on the steering column cover, and a face image acquisition camera that acquires the driver's face image, and the driver's face orientation by image recognition from the acquired face image. It has a look-aside determination ECU that makes a determination and determines whether it is a look-aside according to the determination result. Here, the face image acquisition camera irradiates the driver with near-infrared strobe light so that the face orientation can be determined stably without being affected by environmental conditions such as the brightness of the passenger compartment. It is good to use the camera which acquires. The look-ahead detection device 34 transmits the result of the look-ahead determination in the look-ahead determination ECU to the departure prevention support ECU 10.

  Next, the operation and action of the steering assist device 30 according to the present embodiment will be described. The steering assist device 30 according to the present embodiment repeats the process shown in FIG. 3 as in the first embodiment. In the present embodiment, the target control torque determination process is different from that in the first embodiment.

  In the target control torque determination process, first, the departure prevention assisting ECU 10 recognizes the number of lanes and the lane position of the travel path on which the vehicle travels based on the travel position and lane related information transmitted from the car navigation device 31. Then, based on the vehicle exterior situation output from the white line recognition camera 13, it is determined whether or not the vehicle is performing an offset travel approaching the side without the lane. When such an offset traveling is being performed, it is determined that the torque suppression control expected situation is not satisfied, and the interference determination threshold value is set to 0 so that the interference determination is not established.

  By preventing the interference determination from being established when performing such an offset travel, the interference determination is not satisfied for the offset travel to an obstacle such as a wall immediately outside the white line. Can do. As a result, offset traveling unintended by the driver can be prevented and a sense of security for the control can be given to the driver.

  Here, when the lane-related information transmitted from the car navigation device 31 includes the tentative shared section information, it is possible to prevent the interference determination from being established for the offset travel to the tentative shared line side. . Thus, for example, contact with a pole provided on the temporary shared line can be prevented.

  In addition, when it is determined that the vehicle is not performing an offset travel approaching the side where there is no lane, the presence / absence of the adjacent lane and the travel on the travel path on which the vehicle travels are based on the image transmitted from the surrounding monitoring sensor 32. The presence or absence of obstacles outside of is determined. Here, when there is no adjacent lane on the road and there is an obstacle such as a wall within a certain distance from the road, it is determined that the torque suppression control is not expected, and all the interference determination thresholds are set. As 0, interference judgment is not established.

  By preventing the interference judgment from being satisfied when this condition is satisfied, it is possible to make it difficult for the vehicle to go in the direction in which there is an obstacle and the vehicle may collide, and to deviate from an unintended traveling path. Can be prevented. Although it is not clear whether the deviation from the vehicle travel path is the intention of the driver, at least the deviation in the direction in which the obstacle exists is not the intended deviation. Here, such a deviation can be prevented.

  Further, when the vehicle does not have an adjacent lane on the road and the condition that there is an obstacle within a certain distance from the road, the condition of the driver is determined based on the wakefulness transmitted from the wakefulness detection device 33. The degree of arousal is low, and it is determined whether or not the driver is dozing. Here, when the driver is in the dozing state, it is determined that the torque suppression control is not expected, and the interference determination threshold is set to all 0 so that the interference determination is not established.

  By preventing interference determination when the driver is in a dozing state, interference determination for steering in a direction unintended by the driver at the time of the driver's dozing, particularly in a departure direction that deviates from the driving path, is satisfied. This can be prevented. In this way, it is possible to prevent the vehicle from wobbling when the driver falls asleep.

  Further, when the driver is not in a dozing state, it is determined whether or not the driver is performing a side-by-side driving based on the result of the side-by-side determination transmitted from the side-by-side detection device 34. Here, when the driver is driving aside, it is determined that the torque suppression control is not expected, and the interference determination threshold is set to all 0 so that the interference determination is not established.

  By avoiding the determination of interference when the driver is driving aside, driving in a direction unintended by the driver when the driver is performing a side-by-side driving, particularly in a departure direction that deviates from the road It is possible to prevent the determination of interference with respect to steering from being established. In this way, it is possible to prevent the vehicle from wobbling when the driver is driving aside.

  Subsequently, a third embodiment of the present invention will be described. In the first embodiment, when the target control torque is the low target control torque, the low target control torque is set to a constant value. On the other hand, the steering assist device according to the present embodiment is different from the first embodiment in that the low target control torque is variable according to the time change. Hereinafter, the steering assist device according to the present embodiment will be described focusing on this difference.

  In the steering assist device according to the present embodiment, when the target control torque is set to the low target control torque, the target control torque is decreased as time elapses after the control using the low target control torque is started.

  Specifically, the amount by which the target control torque is reduced is increased in proportion to the time that has elapsed since the start of the control using the low target control torque. Alternatively, the steering torque integration is started after the control with the low target control torque is started, and the amount by which the target control torque is decreased in proportion to the steering torque integration amount is increased.

  Depending on the driver, the vehicle may intentionally travel inside the curve when traveling on a curve, or may travel on the left constantly when traveling linearly. In such a case, the control according to the driver's habit can be performed by reducing the target control torque as the elapsed time from the start of the control with the low target control torque elapses. As a result, the uncomfortable feeling given to the driver can be suitably reduced.

  The preferred embodiments of the present invention have been described above, but the present invention is not limited to the above embodiments. For example, in the first embodiment, when the interference determination low threshold flag is set to ON, the interference determination low threshold flag is set to OFF by determination using the release threshold. . On the other hand, a mode in which the interference determination low threshold flag is turned off according to the situation of the surrounding vehicle may be employed. For example, a side recognition sensor or a rear recognition sensor is provided in the vehicle, and after detecting that the vehicle ahead of the vehicle is overtaken, the interference determination low threshold flag can be turned OFF after a certain period of time. In this case, regardless of whether the preceding vehicle is a large vehicle, a trailer with a long overall length, or a small vehicle with a short overall length, the interference determination low threshold flag is turned OFF at an appropriate timing, and the target control torque is set to the standard target torque. It can be returned to the control torque.

  Further, in the first embodiment, when the vehicle M traveling on the first travel lane L1 detects the front vehicle (large vehicle) M1 traveling on the second travel lane L2, the interference determination low threshold value is detected. The flag is turned on. In this case, when there is no preceding vehicle for the white line on the opposite side of the second travel lane L2 when viewed from the first travel lane L1, the interference determination is easily established. On the other hand, it is also possible to adopt a mode in which the interference determination is not likely to be established for the white line on the opposite side of the second travel lane L2 as viewed from the first travel lane L1.

  Further, in the first embodiment, when the interference determination low threshold flag is turned ON, the interference determination threshold is changed to the interference determination low threshold by satisfying a predetermined condition. However, instead of changing to the interference determination low threshold value to make it easy to establish the interference determination, it is possible to make the interference determination always be established without performing the determination with the threshold value. Further, in the second embodiment, when it is determined that the torque suppression control expected situation is not satisfied, the interference determination threshold is set to all 0 so that the interference determination is not established. Instead of this, when it is determined that the torque suppression control expected state is not satisfied, it is possible to adopt a mode in which interference determination is difficult to be established. Further, when reducing the interference determination threshold value, instead of reducing all of the steering torque threshold value, the control torque threshold value, and the establishment determination time threshold value, a part of them may be reduced. it can.

  On the other hand, in the third embodiment, the target steering torque is reduced in proportion to the time elapsed since the start of the control with the low target control torque and the integral amount of the steering torque after the control with the low target control torque is started. However, the target control torque can be reduced in an appropriate manner regardless of the proportional relationship. Further, in each of the above embodiments, threshold values are set for both the steering torque and the control torque. However, a threshold value may be provided for the difference between the steering torque and the control torque.

It is a block block diagram of the steering assistance device which concerns on 1st Embodiment. It is a front view of a meter. It is a flowchart which shows the control procedure of the steering assistance device which concerns on this invention. It is a flowchart which shows the procedure of a target control torque determination process. It is a top view which shows the state in which a vehicle overtakes a large vehicle. It is a top view explaining the relative relationship between a vehicle and a large vehicle. It is a graph which shows the example of a time-dependent change of steering torque and control torque. It is a block block diagram of the steering assistance device which concerns on 2nd Embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1,30 ... Steering assistance apparatus, 2 ... Steering torque application means, 3 ... Alarm buzzer, 4 ... Meter, 10 ... Deviation prevention assistance ECU, 11 ... Vehicle speed detection means, 12 ... Steering torque detection means, 13 ... White line recognition camera, DESCRIPTION OF SYMBOLS 14 ... Brake switch, 15 ... Winker switch, 16 ... Main switch, 17 ... Forward recognition radar, 31 ... Car navigation apparatus, 32 ... Perimeter monitoring sensor, 33 ... Arousal level detection apparatus, 34 ... Side-arm detection apparatus

Claims (9)

Torque application means for applying auxiliary steering torque to the steering mechanism so that the vehicle travels along the travel path based on an image of the travel path ahead of the vehicle;
Steering torque suppression means for suppressing auxiliary steering torque to be applied to the steering mechanism when the difference between the steering amount by the torque applying means and the steering amount by the steering operation of the vehicle exceeds a predetermined threshold value. A steering assist device,
The driver of the vehicle equipped with the steering assist torque suppression control expected situation determining hands stage determines the torque suppression control expected situation is the situation to expect inhibition of torque by the torque suppression unit,
When the torque suppression control expectation situation determination means determines that the torque suppression control expectation situation is present, the predetermined threshold value is decreased,
The steering amount is a steering force and a steering time,
A steering assist device, wherein a steering force threshold for a steering force and a steering time threshold for a steering time are set as the predetermined threshold . The steering assist device according to claim 1 , wherein the predetermined threshold value is decreased by decreasing the steering force threshold value. The steering assist device according to claim 1 , wherein the predetermined threshold value is reduced by shortening the steering time threshold value.   The steering assist device according to claim 1, wherein the predetermined threshold value is increased when the torque suppression control expectation situation determination unit determines that the torque suppression control expectation situation is not satisfied. The steering assist device according to claim 4 , wherein the torque suppression control expectation situation determination unit determines that the torque suppression control expectation situation is not an expected situation when the driver of the vehicle is in an aside state. The steering assist device according to claim 4 , wherein the torque suppression control expectation situation determination means determines that the torque suppression control expectation situation is not an expected situation when the driver of the vehicle is in a dozing state. A determination duration measuring means for measuring a determination duration that is a time during which it is determined that the torque suppression control expectation situation determination means is a torque suppression control expectation situation;
The steering assist device according to any one of claims 1 to 6 , wherein an amount of suppression of auxiliary steering torque by the steering torque suppression unit is adjusted based on a measurement result of the determination duration measurement unit. The steering assist device according to claim 7 , wherein an amount of suppression of auxiliary steering torque applied to the steering mechanism by the steering torque suppression unit is increased according to a length of the determination duration time. The steering assist according to claim 7 , wherein the amount of suppression of the auxiliary steering torque applied to the steering mechanism by the steering torque suppression unit is increased according to an integrated value of the steering torque by the steering operation during the determination duration time. apparatus.

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