JP6820734B2 - Vehicle travel control device - Google Patents

Description

The present invention relates to a vehicle traveling control device having an automatic driving function capable of automatically turning right or left at an intersection or the like along a target course based on traveling environment information and traveling information of the own vehicle.

Conventionally, various driving assistance technologies have been developed and put into practical use for turning left and right at intersections of vehicles. For example, in Japanese Patent Application Laid-Open No. 2005-189983 (hereinafter, Patent Document 1), the road surface friction coefficient (road surface μ) of the road surface on which the own vehicle travels is estimated, and the own vehicle makes a right turn at an acceleration corresponding to the road surface μ. The time required to complete the right turn from the start to the completion of the right turn is calculated as the right turn completion time, and the possibility of collision between the own vehicle and another vehicle is calculated based on this right turn completion time. A technology for determining and performing alarm control and acceleration / deceleration control of the own vehicle is disclosed.

Japanese Unexamined Patent Publication No. 2005-189983

By the way, in recent years, automatic driving technology has been developed and put into practical use. In such automatic driving, when the own vehicle turns left or right across the front of the oncoming vehicle at an intersection or the like, for example, the control is such that the right or left turn is automatically controlled according to the relative distance between the oncoming vehicle and the own vehicle. In this case, when the road surface condition is low μ road or the like, the tire slips when turning left or right, the target acceleration cannot be obtained, and if there is an oncoming vehicle, there is a risk of contact with the oncoming vehicle. In addition, if the vehicle is equipped with a traction control that reduces the drive torque according to the tire slip condition to prevent the tire from slipping, the traction control is activated when the road surface condition is low μ road or the like. Torque down may occur frequently and the acceleration during right / left turn control may become discontinuous, causing vehicle vibration and causing anxiety and discomfort to the occupants.

The present invention has been made in view of the above circumstances, and in right / left turn control by automatic driving control, it is possible to safely make a right / left turn across the front of an oncoming vehicle with an appropriate drive torque even on a low μ road. Another object of the present invention is to provide a vehicle traveling control device capable of smoothly accelerating when turning left or right and suppressing giving anxiety and discomfort to the occupant.

One aspect of the vehicle travel control device of the present invention includes a travel environment information acquisition means for acquiring the travel environment information in which the own vehicle travels, a travel information detection means for detecting the travel information of the own vehicle, and the above-mentioned travel environment information. In a vehicle travel control device provided with control means for executing automatic driving control based on the travel information of the own vehicle, the control means detects the relative distance between the oncoming vehicle and the own vehicle, and the relative distance is determined in advance. The right / left turn control for causing the own vehicle to perform a right / left turn across the front of the oncoming vehicle when the threshold value or more is set is executed, and the control means is used when the own vehicle executes the right / left turn. When the traction control that reduces the drive torque to prevent the tire from slipping is activated, the preset threshold is increased and corrected at least according to the grip state of the tire, and the traction control is activated to turn left or right. When waiting, it is determined whether or not the own vehicle is in a safe position on the lane, and if it can be determined that the vehicle is in a safe position, the vehicle waits for the above right or left turn.

According to the vehicle travel control device according to the present invention, in right / left turn control by automatic driving control, it is possible to safely make a right / left turn across the front of an oncoming vehicle with an appropriate drive torque even on a low μ road. In addition, the acceleration when turning left or right is smoothly performed, and it is possible to suppress giving anxiety and discomfort to the occupant.

FIG. 3 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 operation control program by one Embodiment of this invention. It is a characteristic diagram of the right turn execution distance by one embodiment of this invention. It is a characteristic diagram of the right turn execution possible distance correction gain by one Embodiment of this invention. It is a characteristic figure of the automatic operation required torque correction amount by one Embodiment of this invention. It is explanatory drawing of the process of making a right turn at an intersection according to one Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In this embodiment, an example will be described in which the vehicle crosses the front of the oncoming vehicle when the vehicle makes a right turn according to the left-hand traffic rule.

In FIG. 1, reference numeral 1 indicates a vehicle travel control device, and the travel control device 1 includes a travel control unit 10, a peripheral environment recognition device 11, a travel parameter detection device 12, and a vehicle position information detection device 13. The vehicle-to-vehicle communication device 14, the road traffic information communication device 15, the switch group 16 input devices, and the engine control device 21, brake control device 22, steering control device 23, display device 24, and speaker buzzer 25 output devices. It is connected.

The surrounding environment recognition device 11 includes a camera device (stereo camera, monocular camera, color camera, etc.) equipped with a solid-state image sensor or the like provided in the vehicle interior for photographing the external environment of the vehicle and acquiring image information, and the periphery of the vehicle. It is composed of a radar device (laser radar, millimeter-wave radar, etc.) that receives reflected waves from a stereoscopic object existing in the camera, a sonar, etc. (not shown above).

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 sets the grouped distance information in advance in a three-dimensional road shape. By comparing with data and three-dimensional object data, lane marking data, side wall data such as guard rails and edge stones existing along the road, three-dimensional object data such as vehicles, etc. can be compared with the relative position (distance, distance, etc.) from the own vehicle. Angle) is extracted along with the speed.

Further, the surrounding environment recognition device 11 detects the position (distance, angle) of the reflected three-dimensional object together with the speed based on the reflected wave information acquired by the radar device. As described above, the surrounding environment recognition device 11 is provided as a traveling environment information acquisition means.

The traveling parameter detection device 12 includes traveling information of the own vehicle, specifically, vehicle speed, front-rear acceleration, lateral acceleration, steering torque, steering wheel angle, yaw rate, accelerator opening, throttle opening, and road surface gradient of the traveling road surface. It detects the estimated road surface friction coefficient, ON-OFF of the brake pedal switch, ON-OFF of the accelerator pedal switch, ON-OFF of the turn signal switch, ON-OFF of the hazard lamp switch, and the like. As described above, the traveling parameter detecting device 12 is provided as a traveling information detecting means.

The own vehicle position information detection device 13 is, for example, a known navigation system, for example, receives radio waves transmitted from a GPS [Global Positioning System] satellite, and receives the radio wave information, an acceleration sensor, and a gyro. The current position is detected based on the information of self-contained navigation based on the vehicle speed signal accompanying the rotation of the tire, and the flash memory, CD (Compact Disc), DVD (Digital Versatile Disc), Blu-ray (Blu-ray; registered trademark) disc. , The position of the own vehicle is specified on the map data stored in advance in the HDD (Hard disk drive) or the like.

The map data stored in advance includes road data and facility data. Road data includes link position information, type information, node position information, type information, curve curvature (curve radius) information, and information on the connection relationship between the node and the link, that is, intersection information, road branching, and merging. It includes location information and maximum vehicle speed information at branch roads. The facility data has multiple records for each facility, and each record contains the name information, location information, and facility type (department store, store, restaurant, parking lot, park, vehicle failure) of the target facility. It has data showing information (by repair base). Then, when the position of the own vehicle on the map position is displayed and the destination is input by the operator, the route from the departure place to the destination is predeterminedly calculated and displayed on the display device 24 such as a display or a monitor. In addition, the speaker buzzer 25 provides voice guidance and guidance. As described above, the own vehicle position information detection device 13 is provided as a traveling environment information acquisition means.

The vehicle-to-vehicle communication device 14 is composed of a narrow-range wireless communication device having a communication area of about 100 [m] such as a wireless LAN, and directly communicates with another vehicle without going through a server or the like to transmit and receive information. It is possible to do it. Then, vehicle information, traveling information, traffic environment information, etc. are exchanged by mutual communication with other vehicles. The vehicle information includes unique information indicating the vehicle type (in this embodiment, the type of passenger car, truck, motorcycle, etc.). In addition, the traveling information includes vehicle speed, position information, lighting information of the brake lamp, blinking information of the direction indicator transmitted when turning left or right, and blinking information of the hazard lamp blinking at the time of emergency stop. Further, the traffic environment information includes information that changes depending on the situation such as road congestion information and construction information. As described above, the vehicle-to-vehicle communication device 14 is provided as a traveling environment information acquisition means.

The Road Traffic Information and Communication System 15 is a so-called Vehicle Information and Communication System (VICS), which is used for FM multiplex broadcasting and transmitters on the road to cause traffic jams, accidents, construction, required time, and parking. It is a device that receives road traffic information of the yard in real time and displays the received traffic information on the map data stored in advance. As described above, the road traffic information communication device 15 is provided as a traveling environment information acquisition means.

The switch group 16 is a group of switches related to driver's driving support control. For example, a switch that controls traveling at a constant speed set in advance, or a vehicle-to-vehicle distance and an inter-vehicle time from a preceding vehicle are set in advance. A switch for maintaining a constant value for follow-up control, a lane keep control switch for maintaining the driving lane in the set lane for driving control, a lane departure prevention control switch for controlling deviation from the driving lane, and a preceding switch. Overtaking control execution permission switch that executes overtaking control of the vehicle (vehicle to be overtaken), switch for executing automatic driving control that performs all of these controls in coordination, vehicle speed, inter-vehicle distance, inter-vehicle distance required for each of these controls It is composed of a switch for setting the time, a speed limit, etc., a switch for releasing each of these controls, and the like.

The engine control device 21 is a fuel for a vehicle engine (not shown) based on, for example, intake air amount, throttle opening degree, engine water temperature, intake air temperature, oxygen concentration, crank angle, accelerator opening degree, and other vehicle information. It is a known control unit that performs main controls such as injection control, ignition timing control, and electronically controlled throttle valve control. Further, the engine control device 21 reduces the driving force (torque down) so that the slip ratio of the tire becomes a preset target slip ratio when a predetermined slip occurs in the drive wheels, for example, a well-known traction. It is configured to run the control. Then, when the engine control device 21 is in the automatic driving state, the traveling control unit 10 can perform the above-mentioned automatic driving control (collision prevention control with obstacles, constant speed running control, follow-up running control, lane keep control, etc.). When the acceleration (required acceleration) required for lane departure prevention control, other overtaking control, etc. is input, the drive torque (automatic driving required torque) is calculated based on the required acceleration, and this automatic driving required torque is calculated. The engine is controlled to the target torque.

The brake control device 22 controls the four-wheel brake device (not shown) independently of the driver's brake operation, based on, for example, a brake switch, four-wheel wheel speed, handle angle, yaw rate, and other vehicle information. It is a known control unit that can perform known ABS control, yaw brake control that controls the yaw moment applied to the vehicle, such as side slip prevention control. Further, in the automatic driving state, the brake control device 22 is subjected to the above-mentioned automatic driving control (collision prevention control with obstacles, constant speed running control, follow-up running control, lane keep control, etc.) from the running control unit 10. When the deceleration required 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. Brake control is performed.

The steering control device 23 is known to control the assist torque by an electric power steering motor (not shown) provided in the steering system of the vehicle based on, for example, vehicle speed, steering torque, steering wheel angle, yaw rate, and other vehicle information. It is a control device. Further, the steering control device 23 maintains the above-mentioned traveling lane in the set lane and controls traveling, lane keeping control for controlling deviation from the traveling lane, lane departure prevention control for controlling deviation from the traveling lane, and automatic driving steering for coordinating these. Control is possible, and the steering angle or steering torque required for these lane keep control, lane departure prevention control, and automatic driving steering control is calculated by the traveling control unit 10 and input to the steering control device 23. The electric power steering motor is driven and controlled according to the input control amount.

The display device 24 is, for example, a device that visually warns and notifies drivers of monitors, displays, alarm lamps, and the like. Further, the speaker buzzer 25 is a device that gives an auditory warning and notification to the driver.

Then, the travel control unit 10 is based on the input signals from the above-mentioned devices 11 to 16 to prevent collision with obstacles and the like, constant speed travel control, follow-up travel control, lane keep control, and lane departure prevention control. , Other overtaking control, etc. are coordinated to execute automatic operation control, etc. In the automatic driving state, the travel control unit 10 performs right / left turn control from a state of being stopped at an intersection or the like when the relative distance Lt between the oncoming vehicle and the own vehicle is equal to or greater than a preset threshold value (right turn executable distance) Ltd. Is designed to make a right turn of the own vehicle that crosses the front of the oncoming vehicle, and when the own vehicle makes a right turn that crosses the front of the oncoming vehicle by right / left turn control, the drive torque is reduced to reduce the tire. When the traction control that prevents slipping is activated, the right turn executable distance Ltd is increased and corrected at least according to the grip state of the tire. Further, when the traction control is activated, the required driving torque for automatic driving in which the traction control is not activated is estimated according to the grip state of the tire, and the estimated automatic driving required torque TAt is used to drive in front of the oncoming vehicle. Make a right turn across. As described above, the traveling control unit 10 is provided as a control means.

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

First, in step 101 (hereinafter, abbreviated as "S") 101, it is determined whether or not it is in the automatic driving state. If it is not in the automatic driving state, the program is exited, and if it is in the automatic driving state, the process proceeds to S102.

Proceeding to S102, it is determined whether or not the own vehicle is stopped at the stop line of the intersection due to a right turn crossing the front of the oncoming vehicle. Specifically, in the present embodiment, according to the left-hand traffic rule, when the own vehicle turns right, it crosses in front of the oncoming vehicle, so that it is recognized as an intersection from the map information and the image information, and the vehicle speed is abbreviated. At 0, when the turn signal switch is turned on to the right, it is recognized that the vehicle is stopped at the stop line at the intersection due to a right turn crossing the front of the oncoming vehicle (for example, the situation at position P1 in FIG. 6). .. The location subject to right turn control is not limited to the intersections described above. For example, the own vehicle stops substantially near the oncoming lane of the lane (vehicle speed is approximately 0), and the turn signal switch is directed to the right. When it is turned on, it may be determined as the place where the right turn control is executed.

Next, the process proceeds to S103, and it is determined whether or not the vehicle has moved from the stopped state. If the vehicle has not moved, the vehicle waits until the vehicle moves, and if the vehicle has moved, the process proceeds to S104.

In S104, it is determined whether or not the traction control is activated when the vehicle starts moving.

As a result of the determination in S104, if the traction control is not operating, the process proceeds to S105, and the process proceeds to S106 without correcting the preset right turn executable distance Ltd. The right turn executable distance Ltd is preset by the relative speed Vr between the oncoming vehicle and the own vehicle as shown in FIG. 3, for example, by experiments or calculations.

Then, when proceeding to S106, a course for turning right is set based on the lane ahead of the right turn and the current lane (or based on the guide route by the navigation system), and the steering angle is set with the course for turning right as the target course. It is set and the target steering angle is output to the steering control device 23. Further, the engine control device 21 generates a preset automatic operation required torque TAt at the time of a right turn to execute the right turn running and execute the right turn control. As described above, this right turn control causes the own vehicle to make a right turn when the relative distance Lt between the oncoming vehicle and the own vehicle is equal to or greater than a preset threshold value (right turn executable distance) Ltd. There is.

Next, the process proceeds to S107, and as shown at position P2 in FIG. 6, it is determined whether or not the traction control is activated during the right turn control. If the traction control does not operate, the process proceeds to S108 and the execution of the right turn control is continued. And exit the program.

Further, if it is determined in S107 that the traction control has been activated, the process proceeds to S109, and the preset right turn executable distance Ltd is corrected. The correction of the right turn executable distance Ltd is performed according to the grip state of the tire, and in the present embodiment, the grip state of the tire is corrected according to the road surface friction coefficient μ between the tire and the road surface.

Specifically, the right turn executable distance correction gain Glh is set according to the road surface friction coefficient μ, and the right turn executable distance correction gain Glh is multiplied by the preset right turn executable distance Ltd for correction.

As shown in FIG. 4, the right turn executable distance correction gain Glh is set to a value of 1 or more, and is set to a larger value as the road surface friction coefficient μ is lower. Therefore, as the road surface friction coefficient μ is lower, the right turn executable distance Ltd is corrected to a longer distance, and the right turn is controlled with a safer margin than when turning right on a normal road surface. For this reason, the safety of right turn control in automatic driving control is improved in consideration of drive delay due to traction control operation on low μ roads and insufficient acceleration due to tire slip.

After correcting the right turn executable distance Ltd in S109, the process proceeds to S110, and the correction of the automatic driving required torque TAt is executed. The correction of the automatic driving required torque TAt is performed according to the grip state of the tire, and in the present embodiment, the correction is performed according to the road surface friction coefficient μ between the tire and the road surface.

Specifically, as shown in FIG. 5, the torque down amount ΔTA of the automatic operation required torque TAt is set according to the road surface friction coefficient μ, and the torque down amount ΔTA is subtracted from the set automatic operation required torque TAt. (TAt-ΔTA). Then, this subtracted value (TAt-ΔTA) is set as the required drive torque for automatic operation in which the traction control does not operate, and the subtracted value (TAt-ΔTA) is set in advance by experiments, calculations, etc. The larger torque value is defined as the automatic driving required torque TAt by comparing with the minimum torque value required for the vehicle to start.

Therefore, when the traction control is activated, then, since the automatic operation principal Motometo torque TAt never traction control is activated it is set, operated traction control again, insufficient acceleration become possible and acceleration Discontinuity is also prevented, the vehicle runs smoothly, and it is effectively prevented that the vehicle vibrates and causes anxiety and discomfort to the occupants.

Next, the process proceeds to S111, and the relative distance Lt between the oncoming vehicle and the own vehicle and the right turn executable distance Ltd are compared, and the relative distance Lt between the oncoming vehicle and the own vehicle and the right turn executable distance Ltd or more (Lt). (When ≧ Ltd), the process proceeds to S108, right turn control is executed, and the program is exited.

On the contrary, when Lt <Ltd, the process proceeds to S112, and it is determined whether or not the own vehicle position is a safe position.

Specifically, this safe position is determined by the amount of movement of the own vehicle (value from the wheel speed sensor, etc.), and if the amount of movement is small and the own vehicle hardly moves from the right turn waiting place, it exists in the safe position. It is designed to judge.

Then, as a result of the determination of S112, if the vehicle position is a safe position, that is, if there is almost no movement from the right turn waiting place, it is determined that the vehicle can safely stand by, and the vehicle returns to S111 and waits until Lt ≧ Ltd. ..

On the contrary, when it is determined that the position of the own vehicle is not in the safe position, the amount of movement of the own vehicle is large, and the road surface friction coefficient μ is expected to be as high as the own vehicle can move. In order to prevent contact with the vehicle, the vehicle proceeds to S108, a right turn control is executed, and the vehicle quickly leaves the oncoming lane.

On the other hand, in the above-mentioned S104, when it is determined that the traction control is activated when the vehicle starts moving, the process proceeds to S113, and the right turn executable distance Ltd set in advance by the same method as in the above-mentioned S109. Perform the correction.

Next, the process proceeds to S114, and the automatic operation required torque TAt is corrected by the same method as in S110 described above.

Next, the process proceeds to S115, the right turn control is executed, the process proceeds to S116, and as shown at the position P2 in FIG. 6, it is determined whether or not the traction control is activated during the right turn control, and if the traction control is not activated, it is determined. , S108, continue executing the right turn control and exit the program.

Further, if it is determined in S116 that the traction control has been activated, the process proceeds to S117, and the preset right turn executable distance Ltd is corrected by the same method as in S109 described above.

Next, the process proceeds to S118, and the automatic operation required torque TAt is corrected by the same method as in S110 described above.

Next, the process proceeds to S119, and the relative distance Lt between the oncoming vehicle and the own vehicle and the right turn executable distance Ltd are compared. When the relative distance Lt between the oncoming vehicle and the own vehicle and the right turn executable distance Ltd or more ( (When Lt ≧ Ltd), the process proceeds to S108, right turn control is executed, and the program is exited.

On the contrary, when Lt <Ltd, the process proceeds to S120, and it is determined whether or not the own vehicle position is a safe position.

Then, as a result of the determination of S120, if the own vehicle position is a safe position, that is, if there is almost no movement from the right turn waiting place, it is determined that the vehicle can safely stand by, and the vehicle returns to S119 and waits until Lt ≧ Ltd. ..

On the contrary, when it is determined that the position of the own vehicle is not in the safe position, the amount of movement of the own vehicle is large, and the road surface friction coefficient μ is expected to be as high as the own vehicle can move. In order to prevent contact with the vehicle, the vehicle proceeds to S108, a right turn control is executed, and the vehicle quickly leaves the oncoming lane.

As described above, according to the embodiment of the present invention, in the automatic driving state, in the right turn control from the state of being stopped at an intersection or the like, the relative distance Lt between the oncoming vehicle and the own vehicle is equal to or more than the right turn feasible distance Ltd. In some cases, the vehicle is made to turn right, and when the vehicle makes a right turn with right turn control, at least the tires are operated when the traction control that reduces the driving torque to prevent the tires from slipping is activated. The right turn executable distance Ltd is increased and corrected according to the grip condition of. Further, when the traction control is activated, the required driving torque for automatic driving in which the traction control is not activated is estimated according to the grip state of the tire, and the right turn is executed with the estimated automatic driving required torque TAt.

Specifically, the lower the road surface friction coefficient μ, which indicates the grip state of the tire, the longer the right turn executable distance Ltd is corrected, and the right turn is controlled with a safer margin than when turning right on a normal road surface. The safety of right turn control in automatic driving control is improved in consideration of drive delay due to traction control operation on low μ roads and insufficient acceleration due to tire slippage. Further, the torque down amount ΔTA of the automatic operation required torque TAt is set according to the road surface friction coefficient μ, and the torque down amount ΔTA is subtracted from the set automatic operation required torque TAt. Then, this subtracted value is used as the required drive torque for automatic driving in which the traction control does not operate, and the subtracted value and the minimum torque required for the vehicle to start, which are set in advance by experiments, calculations, etc. The larger torque value compared with the value is defined as the automatic operation required torque TAt. Therefore, when the traction control is activated, then, since the automatic operation principal Motometo torque TAt never traction control is activated it is set, operated traction control again, insufficient acceleration become possible and acceleration Discontinuity is also prevented, the vehicle runs smoothly, and it is effectively prevented that the vehicle vibrates and causes anxiety and discomfort to the occupants.

In the present embodiment, the left-hand traffic rule describes an example in which the vehicle crosses the front of the oncoming vehicle when the vehicle turns right, but the right-hand traffic rule describes the oncoming vehicle when the vehicle turns left. It goes without saying that the present invention can be applied in the same manner when crossing the front.

1 Travel control device 10 Travel control unit (control means)
11 Surrounding environment recognition device (driving environment information acquisition means)
12 Driving parameter detection device (driving information detecting means)
13 Vehicle position information detection device (driving environment information acquisition means)
14 Vehicle-to-vehicle communication device (driving environment information acquisition means)
15 Road traffic information communication device (driving environment information acquisition means)
16 Switch group 21 Engine control device 22 Brake control device 23 Steering control device 24 Display device 25 Speaker buzzer

Claims (3)

Driving environment information acquisition means for acquiring driving environment information on which the own vehicle is traveling, driving information detecting means for detecting the driving information of the own vehicle, and automatic driving control based on the driving environment information and the driving information of the own vehicle. In a vehicle travel control device equipped with a control means to execute
The control means executes right / left turn control that detects the relative distance between the oncoming vehicle and the own vehicle and causes the own vehicle to make a right / left turn across the front of the oncoming vehicle when the relative distance is equal to or greater than a preset threshold value. To do
The control means is set in advance at least according to the grip state of the tire when the traction control that reduces the torque of the drive torque and prevents the tire from slipping is activated when the own vehicle executes the right / left turn. When the traction control is activated and the vehicle waits for the right / left turn, it is judged whether or not the vehicle is in a safe position on the lane, and when it can be determined that the vehicle is in the safe position, the vehicle waits for the right / left turn. A vehicle travel control system characterized by. When the traction control is activated, the control means estimates a required drive torque for automatic driving in which the traction control does not operate according to the grip state of the tire, and is based on the estimated required drive torque. The vehicle travel control device according to claim 1, wherein the right / left turn is executed with the required torque for automatic driving. The vehicle travel control device according to claim 1 or 2 , wherein the grip state of the tire is determined by a road surface friction coefficient between the tire and the road surface.

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