JP2017165277A - Traveling control device of vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate the necessity for additionally mounting a device and control for, in particular, a failure of a steering system, and to improve the control continuation of automatic drive.SOLUTION: In the case that automatic drive control is performed in a steering-wheel non-holding state by a driver in an automatic drive control state, when a curve radius R of a lane in which an own vehicle travels is a curve radius not larger than a preset threshold Rd, a traveling control device of a vehicle urges the driver to hold the steering wheel, and performs an automatic drive steering holding mode. When the driver is in a steering-wheel non-holding state, the control device decreases a control amount by the automatic drive, and transits the vehicle to manual drive by the driver, and on the other hand, when the driver is in a steering-wheel holding state, the control device transits the vehicle to normal automatic drive control when the curve radius of the lane in which the vehicle travels exceeds the preset threshold Rd.SELECTED DRAWING: Figure 2

Description

  The present invention particularly relates to a travel control device for a vehicle that travels automatically on a curved road.

  In recent years, in vehicles, various technologies related to automatic driving control have been developed and put into practical use so that drivers can drive more comfortably and safely. In such automatic driving control, when a failure occurs in a control system that is automatically steered so as to travel along a target course, the target course has a curved shape, and an electric power steering motor or the like during the curve turning. If the car breaks down, the self-aligning torque of the tire causes a steering return and causes a deviation from the curved lane. In response to such a failure of the steering system, for example, in Japanese Patent Laid-Open No. 2012-166715 (hereinafter referred to as Patent Document 1), when the front wheel steering function is lost, the slip angle and the yaw rate are controlled by rear wheel steering or left / right brake control. A technique for a vehicle travel control device that controls to maintain the above is disclosed.

JP2012-166715A

  However, with the technology disclosed in Patent Document 1 described above, the number of on-board devices and control are significantly increased, and it is difficult to coordinate these for each vehicle type on which each is mounted, and the cost is low. There is a problem of inviting up. Furthermore, even if a failure occurs in the steering system during automatic driving, the limit radius of the curve that can be driven by automatic driving is set in consideration of the time that the vehicle stays in the lane. If it is less than the radius, it can be considered that the automatic driving is turned off. However, in such automatic driving control, depending on the lane, the automatic driving OFF state frequently occurs, There is a problem that it becomes difficult to ensure control continuity of automatic operation.

  The present invention has been made in view of the above circumstances, and in particular, it is not necessary to additionally install a device or control for the failure of the steering system, and the control continuity of automatic driving can be improved. An object of the present invention is to provide a vehicle travel control device.

  One aspect of the vehicle travel control apparatus of the present invention is a travel environment information acquisition unit that acquires travel environment information in which the host vehicle travels, a travel information detection unit that detects travel information of the host vehicle, and the travel environment information In a vehicle travel control device that executes automatic driving control based on the travel information of the host vehicle, steering holding state detection means for detecting a holding state of a steering wheel of a driver, and the automatic operation when the driver does not hold the steering wheel. When driving control is being executed, if the curve radius of the lane in which the host vehicle is traveling is less than a preset threshold value, the driver is encouraged to hold the steering wheel and the driver's steering wheel The driver will drive without holding the steering wheel according to the holding state and the curve radius of the driving lane. And a automatic driving steering hold mode executing means for executing the automatic operation fixed steering mode to shift to either manual operation by the ability of normal automatic operation control and driver.

  According to the vehicle travel control device of the present invention, in particular, it is not necessary to additionally install a device or control due to a failure of the steering system, and it is possible to improve control continuity of automatic driving. Become.

1 is an overall configuration diagram of a vehicle travel control device according to an embodiment of the present invention. It is a flowchart of the automatic driving | operation control program by one Embodiment of this invention. It is explanatory drawing which shows an example of the characteristic of the threshold value set according to the vehicle speed by one Embodiment of this invention. It is explanatory drawing of the vehicle which drive | works a curve, and a curve radius by one Embodiment of this invention. FIG. 5A is an explanatory diagram showing limits on the lane travel distance and the curve radius that change depending on the holding state of the steering wheel of the driver according to the embodiment of the present invention. FIG. (B) shows a steering wheel holding state.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  In FIG. 1, reference numeral 1 denotes a vehicle travel control device. The travel control device 1 includes a travel control unit 10, a surrounding environment recognition device 11, a driver state detection device 12, a travel parameter detection device 13, Position information detection device 14, inter-vehicle communication device 15, road traffic information communication device 16, input devices of switch group 17, engine control device 21, brake control device 22, steering control device 23, display device 24, speaker / buzzer 25 output devices are connected.

  The surrounding environment recognition device 11 includes a camera device (stereo camera, monocular camera, color camera, etc.) provided with a solid-state imaging device or the like provided in a vehicle interior that captures image information by capturing an external environment of the vehicle, 1 is constituted by a radar device (laser radar, millimeter wave radar, etc.) for receiving a reflected wave from a three-dimensional object, sonar (not shown).

  The surrounding environment recognition device 11 performs, for example, a well-known grouping process on the distance information based on the image information captured by the camera device, and the three-dimensional road shape in which the grouping distance information is set in advance. Three-dimensional objects such as lane marking data, guardrails along the road, side walls such as curbs, vehicles (preceding vehicles, oncoming vehicles, parallel vehicles, parked vehicles) The relative position (distance, angle) from the host vehicle is extracted along with the speed of data and the like.

  The surrounding environment recognition device 11 detects the position (distance, angle) of the reflected three-dimensional object along with the speed based on the reflected wave information acquired by the radar device. Thus, the surrounding environment recognition device 11 is provided as a traveling environment information acquisition unit.

  The driver state detection device 12 is a biological detection sensor for a steering wheel that is provided on a steering wheel as disclosed in, for example, Japanese Patent Laid-Open No. 2013-90834 and detects a biological signal of the driver. The steering wheel living body detection sensor detects the holding state of the driver's steering wheel. That is, the driver state detection device 12 is provided as a steering holding state detection means.

  The travel parameter detection device 13 includes travel information of the host vehicle, specifically, vehicle speed, longitudinal acceleration, lateral acceleration, steering angle, steering torque, yaw rate, accelerator opening, throttle opening, and road surface gradient of the traveling road surface, The estimated value of the road friction coefficient is detected. Thus, the travel parameter detection device 13 is provided as travel information detection means.

  The own vehicle position information detecting device 14 is, for example, a known navigation system, and receives, for example, a radio wave transmitted from a GPS (Global Positioning System) satellite and determines the current position based on the radio wave information. Detected on map data stored in advance in flash memory, CD (Compact Disc), DVD (Digital Versatile Disc), Blu-ray (Blu-ray: registered trademark) disk, HDD (Hard disk drive), etc. Identify your vehicle position.

  The map data stored in advance includes road data and facility data. The road data includes link position information, type information, node position information, type information, curve curvature (or curve radius) at the node, and information on the connection relationship between the node and the link, that is, road branching and merging. It includes point information and maximum vehicle speed information on branch roads. The facility data has a plurality of records for each facility, and each record includes the name information of the target facility, location information, facility type (department store, store, restaurant, parking lot, park, vehicle failure) It has data that shows information). When the vehicle position on the map position is displayed and a destination is input by the operator, a route from the departure point to the destination is calculated in a predetermined manner and displayed on a display device 24 such as a display or a monitor. In addition, the speaker / buzzer 25 can be guided by voice guidance. Thus, the own vehicle position information detection device 14 is provided as a travel environment information acquisition unit.

  The inter-vehicle communication device 15 is composed of, for example, a narrow-area wireless communication device having a communication area of about 100 [m] such as a wireless LAN, and directly communicates with other vehicles without passing through a server or the like to transmit and receive information. It is possible to do. And vehicle information, traveling information, traffic environment information, etc. are exchanged by mutual communication with other vehicles. The vehicle information includes specific information indicating the vehicle type (in this embodiment, the type of passenger car, truck, motorcycle, etc.). The traveling information includes vehicle speed, position information, brake lamp lighting information, blinking information of a direction indicator transmitted at the time of turning left and right, and blinking information of a hazard lamp blinking at an emergency stop. Furthermore, the traffic environment information includes information that varies depending on the situation such as road traffic congestion information and construction information. Thus, the inter-vehicle communication device 15 is provided as a travel environment information acquisition unit.

  The road traffic information communication device 16 is a so-called road traffic information communication system (VICS: Vehicle Information and Communication System: registered trademark). The road traffic information of the car park is received in real time, and the received traffic information is displayed on the previously stored map data. Thus, the road traffic information communication device 16 is provided as a travel environment information acquisition unit.

  The switch group 17 is a switch group related to the driver's driving support control. For example, the switch group 17 is a switch that controls the traveling at a constant speed that is set in advance, or the distance between the preceding vehicle and the time between the preceding cars are set in advance. A switch for keeping track at a constant value, a lane keeping control switch for driving control while maintaining the driving lane at the set lane, a lane departure preventing control switch for preventing departure from the driving lane, and preceding Passing control execution permission switch for executing overtaking control of vehicles (vehicles to be overtaken), switch for executing automatic driving control for performing all these controls in cooperation, vehicle speed, inter-vehicle distance, inter-vehicle distance required for each control It consists of a switch for setting time, speed limit, etc., or a switch for canceling each control.

  The engine control device 21 uses, for example, a fuel for a vehicle engine (not shown) based on the intake air amount, throttle opening, engine water temperature, intake air temperature, oxygen concentration, crank angle, accelerator opening, and other vehicle information. This is a known control unit that performs main control such as injection control, ignition timing control, and control of an electronically controlled throttle valve. Further, the engine control device 21 receives the above-described automatic driving control (collision prevention control with obstacles, constant speed driving control, following driving control, lane keeping control, When an acceleration (requested acceleration) required for lane departure prevention control, other overtaking control, etc.) is input, a drive torque (automatic driving request torque) is calculated based on the required acceleration, and the automatic driving request torque is calculated. The engine is controlled to the target torque.

  The brake control device 22 controls a four-wheel brake device (not shown) independently of a driver's brake operation based on, for example, a brake switch, four-wheel wheel speed, steering wheel angle, yaw rate, and other vehicle information. This is a known control unit that performs a known yaw brake control for controlling a yaw moment applied to the vehicle, such as a known ABS control or a side slip prevention control. Further, the brake control device 22 receives the above-mentioned automatic driving control (collision prevention control with obstacles, constant speed driving control, following driving control, lane keeping control, When the necessary deceleration (required deceleration) for lane departure prevention control, other overtaking control, etc.) is input, the target hydraulic pressure of the wheel cylinder of each wheel brake is set based on the required deceleration, Perform brake control.

  The steering control device 23 controls the assist torque by an electric power steering motor (not shown) provided in the vehicle steering system based on, for example, vehicle speed, steering torque, steering wheel angle, yaw rate, and other vehicle information. It is a control device. In addition, the steering control device 23 maintains the above-mentioned traveling lane in the set lane and performs lane keeping control for performing traveling control, lane departure preventing control for performing departure prevention control from the traveling lane, and automatic driving steering for executing these in coordination. The target steering angle and target steering torque necessary for the lane keeping control, the lane departure prevention control, and the automatic driving steering control are calculated by the traveling control unit 10 and input to the steering control device 23. The electric power steering motor is driven and controlled in accordance with the input control amount. Specifically, for example, the traveling control unit 10 performs steering control in automatic driving using the target steering angle θt calculated by the following equation (1) as a control amount.

θt = G · (1 + A · V ² ) · (l / R) · n (1)
Here, G is a preset gain that determines the weight of the control amount, A is a stability factor specific to the vehicle, V is the vehicle speed, l is the wheelbase, R is the curve radius of the target course of the lane, and n is the steering gear ratio. It is. The curve radius R may be a target course (for example, the center of the lane) recognized from the image information of the side environment recognition device 11 and is obtained from the map information of the navigation system of the vehicle position information detection device 14. There may be.

  The display device 24 is a device that provides a visual warning and notification to drivers such as a monitor, a display, and an alarm lamp. The speaker / buzzer 25 is a device that gives an audible warning and notification to the driver.

  And the traveling control part 10 is based on each input signal from each apparatus 11-17 mentioned above, collision prevention control with an obstruction etc., constant speed traveling control, follow-up traveling control, lane keeping control, lane departure prevention control In addition, automatic driving control or the like is executed by performing overtaking control or the like in cooperation. In this automatic driving control state, the traveling control unit 10 sets a threshold value Rd that is set in advance by the curve radius R of the lane in which the host vehicle travels when the automatic driving control is executed while the driver does not hold the steering wheel. In the case of the following curve radii, the driver is encouraged to hold the steering wheel, and the driver can drive without holding the steering wheel according to the holding state of the driver's steering wheel and the curve radius R of the driving lane. The automatic driving / maintenance mode for shifting to either normal automatic driving control or manual driving by the driver is executed. As described above, the traveling control unit 10 is provided with the function of the automatic driving / holding mode execution means.

  Next, an automatic driving control program executed by the travel control unit 10 will be described with reference to the flowchart of FIG.

  First, in step (hereinafter abbreviated as “S”) 101, it is determined whether or not the vehicle is in an automatic operation state. Advances to S102.

  When it is determined in S101 that the vehicle is in the automatic driving state and the process proceeds to S102, it is determined whether or not the curve radius R is equal to or less than the threshold value Rd.

  This threshold value is variably set according to the vehicle speed V as shown in FIG.

  That is, as shown in FIG. 4, in a vehicle traveling on a curve, when the steering angle is 0, the following equation (2) is established for deviation from the curve in the tangential direction.

d = (1/2) · (d ² y / dt ² ) ₀ · t ² (2)
Here, d is the amount of bulging outward from the target course, (d ² y / dt ² ) ₀ is the original turning lateral acceleration, and t is the elapsed time.

Further, since the relationship of (d ² y / dt ² ) ₀ = V ² / R is established, the following expression (3) is obtained.

R = (1/2) · V ² / d · t ² (3)
In this equation (3), the amount d of bulging outward from the target course is the distance do from the right side of the vehicle body to the lane marking on the outside of the curve, and t is replaced with the lane holding time tk that allows the vehicle to be maintained in the lane. Thus, the following expression (4) is obtained. In FIG. 4, Wb represents the vehicle width, Wr represents the lane width, and di represents the distance from the left side surface of the vehicle body to the lane marking on the inside of the curve.

R = (1/2) · V ² / do · tk ² (4)
As is clear from the equation (4), the curve radius R varies greatly depending on the in-lane holding time tk.

  That is, when the driver does not hold the steering wheel (in the case of FIG. 5 (a)), a delay occurs until the driver steers, so the travel distance due to the in-lane holding time tk becomes longer and the steering system is lost. If it falls, the limit radius of the curve is increased so that it can be maintained in the lane.

  Conversely, when the driver is holding the steering wheel (in the case of FIG. 5 (b)), the driver can respond immediately, so the driving distance due to the in-lane holding time tk is shortened and the steering system is lost. The limit radius of the curve for maintaining in the lane can be set small.

  In the embodiment of the present application, considering such a difference in the in-lane holding time tk, even if the driver does not hold the steering wheel as shown in FIG. As shown in FIG. 3, the lane holding time tk is determined by experiment, calculation, etc., taking into account the vehicle-specific steering characteristics and the like, and the threshold value Rd serving as the limit value of the curve radius R is as shown in FIG. It is something to set.

  If it is determined in S102 described above that the curve radius R is larger than the threshold value Rd (when R> Rd), the automatic operation is continued as it is.

  Conversely, when it is determined in S102 that the curve radius R is equal to or less than the threshold value Rd (when R ≦ Rd), the vehicle is maintained in the lane even if the steering system fails. Proceed to urge the driver to hold the steering wheel. This is performed by visual notification by the display device 24 or auditory notification by the speaker / buzzer 25.

  Next, the process proceeds to S104, and a transition is made to an automatic driving steering holding mode in which the driver holds the steering wheel and performs automatic driving control.

  When shifting to the steering mode for automatic driving, first, in S105, it is determined whether the driver is holding the steering wheel. If it is determined that the driver is holding the steering wheel, the process proceeds to S106, where the curve radius R is set. It is determined whether it is larger than the threshold value Rd (R> Rd) or whether the traveling road is a substantially straight road. This threshold value Rd is set again with reference to the map of FIG.

  If the curve radius R is equal to or less than the threshold value Rd (R ≦ Rd) as a result of the determination in S106, the determination in S105 is repeated, and if R> Rd, or if the traveling road is a substantially straight road, the process proceeds to S107 and automatic driving is performed. The return from the steering holding mode is notified by the display device 24 or the speaker / buzzer 25, and the process proceeds to S108 where the driver returns to normal automatic driving control capable of driving without holding the steering wheel and exits the program.

  On the other hand, if it is determined in S105 that the driver does not hold the steering wheel, the process proceeds to S109, where the automatic driving control amount is gradually decreased, and the steering control is turned off. Specifically, this is performed by gradually decreasing the gain G in the above-described equation (1) gradually to 0 by a rate limiter process or the like.

  And it progresses to S110 and transfers to manual operation by a driver. When the driver shifts to manual operation in this way, the driver is notified by the display device 24 and the speaker / buzzer 25.

  As described above, according to the embodiment of the present invention, in the state of the automatic driving control, the traveling control unit 10 determines that the host vehicle is running when the driver is executing the automatic driving control without holding the steering wheel. If the curve radius R of the driving lane is less than the preset threshold Rd, the driver is encouraged to hold the steering wheel, the automatic driving hold mode is executed, and the driver does not hold the steering wheel. In this case, the control amount by automatic driving is gradually reduced to shift to manual driving by the driver. On the other hand, when the driver is holding the steering wheel, the curve radius R of the traveling lane exceeds a preset threshold Rd To normal automatic operation control. For this reason, even when driving on a curve, it is not particularly necessary to additionally install devices and controls due to the failure of the steering system, and automatic driving is minimized in the curve. As a result, it is possible to improve the control continuity of automatic driving.

  Note that the threshold value Rd used for the determination to enter the automatic driving / holding mode in S102 described above and the threshold value Rd used for the determination to return to the normal automatic driving control from the automatic driving / holding mode in S106 include, for example, hysteresis. And may be set to different values.

  In addition, as described in the present embodiment, in order to execute normal automatic driving control, R> Rd, or since the traveling path is a substantially straight road, the driver turns on the automatic driving execution switch. In this case, R> Rd or a case where the traveling road is a substantially straight road may be set as one of the conditions for executing the automatic driving control.

DESCRIPTION OF SYMBOLS 1 Traveling control apparatus 10 Traveling control part (automatic driving | running | working maintenance mode execution means)
11 Ambient environment recognition device (traveling environment information acquisition means)
12 Driver state detection device (steering holding state detection means)
13 Travel parameter detection device (travel information detection means)
14 Vehicle position information detection device (traveling environment information acquisition means)
15 Vehicle-to-vehicle communication device (running environment information acquisition means)
16 Road traffic information communication device (running environment information acquisition means)
17 Switch group 21 Engine control device 22 Brake control device 23 Steering control device 24 Display device 25 Speaker buzzer

Claims (4)

Driving environment information acquisition means for acquiring driving environment information in which the host vehicle travels, driving information detection means for detecting driving information of the host vehicle, and automatic driving control based on the driving environment information and the driving information of the host vehicle. In the vehicle travel control device to be executed,
Steering holding state detecting means for detecting the holding state of the steering wheel of the driver;
When the driver does not hold the steering wheel and the above automatic driving control is being executed, if the curve radius of the lane in which the vehicle is traveling is less than a preset threshold value, the driver holds the steering wheel. Depending on the holding state of the steering wheel of the driver and the curve radius of the driving lane, the driver can perform either automatic driving control that allows the driver to drive without holding the steering wheel or manual driving by the driver. A vehicle travel control apparatus comprising: an automatic driving / holding mode executing means for executing an automatic driving / holding mode to be transferred.   The automatic driving / holding mode execution means, when the driver is not holding the steering wheel in the automatic driving / holding mode, gradually reduces the control amount by automatic driving and shifts to manual driving by the driver. The travel control device for a vehicle according to claim 1.   In the automatic driving / holding mode, the automatic driving / holding mode execution means is configured to perform the above operation when the curve radius of the traveling lane exceeds the preset threshold when the driver is holding the steering wheel. 3. The vehicle travel control device according to claim 1, wherein the vehicle travel control device is shifted to normal automatic driving control.   4. The vehicle travel control apparatus according to claim 1, wherein the preset threshold value is variably set according to a vehicle speed.

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