JP6535482B2 - Vehicle travel control system - Google Patents

Description

  The present invention relates to a travel control system of a vehicle that recognizes travel environment, detects travel information of a host vehicle, and performs automatic driving control.

  In recent years, in vehicles, various systems using automatic driving technology have been developed and proposed in order to perform driving of a driver more comfortably and safely. In such a system of automatic driving, if the driver performs a predetermined driving operation (steering operation, accelerator pedal or brake pedal operation) while executing automatic driving control, automatic driving control is given priority by giving priority to the driver's intention. It has an override function that pauses and switches to manual operation by the driver.

  For example, Patent Document 1 discloses a technology for switching a driving state by detecting a steering angle or a steering angular velocity to determine a steering intervention by a driver during automatic driving in which correction steering for avoiding lane departure is given.

JP 2003-81115 A

  In the conventional override determination as disclosed in Patent Document 1, when the driver's intervention is determined, the automatic operation is uniquely stopped to switch to the manual operation by the driver, but it is transiently intermediate The driver may desire to perform the manual operation while continuing the automatic operation, and may eventually want to return to the automatic operation or switch to the manual operation.

  In such a case, the driving state can not be switched smoothly and appropriately in the conventional overriding determination, which may not only give the driver a sense of discomfort or anxiety, and may deteriorate drivability.

  The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a travel control system of a vehicle capable of switching a driving state smoothly and appropriately by overriding determination in automatic driving.

A travel control system for a vehicle according to an aspect of the present invention is a travel control system for a vehicle that executes automatic drive control based on travel environment information of an environment in which the host vehicle travels and travel information of the host vehicle. In this case, whether the overriding conditions for the first operation mode for performing coordinated control of automatic operation and manual operation or the second operation mode for allowing manual operation after stopping the automatic operation are satisfied and determining override determination unit configured to determine, the over - according to riding judging section determination result, and a driving mode switching unit for switching between automatic operation and said first mode of operation and said second operation mode, the The override determination unit sets the area of the first operation mode and the area of the second operation mode using two parameters representing the state of the steering system, and the first operation mode is set. The threshold values of the respective parameters defining the region and the region of the second operating mode, variable according to the running state as a determination threshold value the override condition.

  According to the present invention, it is possible to smoothly and appropriately switch the driving state by the override determination in the automatic driving.

Overall configuration of travel control system of vehicle Explanatory drawing showing an example of switching from manual operation to manual operation temporarily Explanatory drawing showing the judgment area of override Flow chart of operation mode switching process

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In FIG. 1, reference numeral 1 denotes a travel control system of a vehicle configured around a travel control device 10. The traveling control device 10 includes a surrounding environment recognition device 15, a vehicle position information detection device 16, an inter-vehicle communication device 17, a road traffic information communication device 18, an engine control device 20, a brake control device 21, a steering control device 22, an alarm The devices 23 and the like are connected via a communication bus 100 forming an in-vehicle network, and switches 19 for various settings and operations are connected.

  The peripheral environment recognition device 15 is a camera device (a stereo camera, a monocular camera, a color camera, etc .: not shown) provided with a solid-state image pickup device etc. provided in a vehicle interior that captures the outside environment of the vehicle and acquires image information. And a radar device (laser radar, millimeter wave radar, ultrasonic radar, etc .: not shown) for receiving a reflected wave from a three-dimensional object present around the vehicle.

  The surrounding environment recognition device 15 performs known grouping processing on distance information, for example, based on image information captured by a camera device, and sets three-dimensional road shape in which the distance information subjected to grouping processing is set in advance. By comparing the lane marking data, guardrails that exist along the road, side wall data such as curbs, and three-dimensional object data such as vehicles by comparing them with data, three-dimensional object data, etc. Extract the angle) along with the velocity.

  In addition, the surrounding environment recognition device 15 detects the position (distance, angle) of the reflected three-dimensional object together with the velocity based on the reflected wave information acquired by the radar device. In the present embodiment, the maximum distance (the distance to a three-dimensional object, the farthest distance of the lane markings) that can be recognized by the surrounding environment recognition device 15 is considered to be visible. Furthermore, the surrounding environment recognition device 15 outputs the abnormality of the surrounding environment recognition device 15 to the traveling control device 10, for example, when the accuracy of the surrounding environment recognition decreases due to an abnormality such as a camera device or a radar device or bad weather. Do.

The vehicle position information detection device 16 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. On map data stored in advance in flash memory, CD (Compact Disc), DVD (Digital Versatile Disc), Blu-ray (Blu-ray (registered trademark) disc), HDD (Hard disk drive), etc. Identify your vehicle position.

  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, and connection information of nodes and links, that is, branching of roads, merging point information, maximum vehicle speed information at branching roads, etc. It contains. The facility data has a plurality of records for each facility, and each record includes name information of the target facility, location information, facility type (department store, store, restaurant, parking lot, park, at the time of breakdown of the vehicle) It has the data which shows the information of repair base separately. Then, the vehicle position on the map position is displayed, and when the destination is input by the operator, the route from the departure place to the destination is calculated in a predetermined manner, and the image display on the display and the voice guidance from the speaker It is inducible by

  The inter-vehicle communication device 17 is, for example, a wireless communication device having a predetermined communication area, and can communicate with other vehicles to transmit and receive information. And vehicle information, travel information, traffic environment information, etc. are exchanged by mutual communication with other vehicles. As the vehicle information, there is unique information indicating a vehicle type (in the present embodiment, a type of a car, a truck, a two-wheeler, etc.). The traveling information includes vehicle speed, position information, lighting information of the brake lamp, blinking information of the direction indicator transmitted at the time of turning to the left and right, and blinking information of the hazard lamp blinking at the time of emergency stop. Furthermore, the traffic environment information includes information that changes depending on the conditions such as traffic congestion information on roads and construction information.

  The road traffic information communication device 18 is a so-called road traffic information communication system (VICS: Vehicle Information and Communication System: registered trademark), and from traffic broadcasts on FM multiplex broadcasting and transmitters on the road, traffic jams, accidents, construction, required time, Road traffic information of the parking lot is received in real time, and the received traffic information is displayed on the previously stored map data.

  The switch group 19 is a switch group related to the driving assistance control of the driver, for example, a switch for performing travel control at a constant speed whose speed is preset, or an inter-vehicle distance to the preceding vehicle and an inter-vehicle time Switch for keeping track at keeping constant value, Switch for lane keeping control to keep running lane on set lane, switch for lane departure prevention control to run departure prevention control from running lane, Lead An overtaking control execution permission switch for executing overtaking control of a car (overtaking target vehicle), a switch for executing automatic operation control for cooperatively performing all of these controls, a vehicle speed necessary for each control, an inter-vehicle distance, an inter-vehicle It is comprised from the switch which sets time, a speed limit, etc., or the switch etc. which cancel these each control.

  The engine control device 20 is a known control unit that controls the operating state of a vehicle engine (not shown). For example, the intake air amount, throttle opening degree, engine water temperature, intake air temperature, air fuel ratio, crank angle, accelerator Main control such as fuel injection control, ignition timing control, and opening control of the electronically controlled throttle valve is performed based on the opening and other vehicle information.

  The brake control device 21 makes the four-wheel brake system (not shown) independent of the driver's brake operation based on, for example, the brake switch, the wheel speed of the four wheels, the steering wheel angle θH, the yaw rate γ and other vehicle information. It is controllable by the well-known antilock brake system (Antilock Brake System), yaw moment control that controls the yaw moment applied to the vehicle such as anti-slip control, and well-known control unit that performs yaw brake control. is there. Then, when the braking force of each wheel is input from the traveling control device 10, the brake control device 21 calculates the brake fluid pressure of each wheel based on the braking force, and the brake drive unit (not shown) )).

  The steering control device 22 is based on, for example, a vehicle speed V, a driver's steering torque Tdrv, a steering wheel angle θH, a yaw rate γ, and other vehicle information, and assist torque by an electric power steering motor (not shown) provided in a steering system of the vehicle. Control unit, which is a well-known control unit. In addition, the steering control device 22 can perform lane keeping control for maintaining the above-mentioned traveling lane at the set lane and performing travel control, and lane departure prevention control for performing departure prevention control from the traveling lane. The steering angle or steering torque required for lane departure prevention control is calculated by the travel control device 10 and input to the steering control device 22, and drive control of the electric power steering motor is performed according to the input control amount. . Further, the steering control device 22 detects an abnormality such as a steering system including a steering mechanism, a steering torque sensor, a steering wheel angle sensor, etc. The occurrence of these abnormal states is monitored by the traveling control device 10. There is.

  The alarm device 23 is a device that appropriately generates an alarm when an abnormality occurs in various devices of the vehicle, and, for example, a visual output such as a monitor, a display, an alarm lamp, etc. Warning and notification are performed using at least one of the outputs. Further, when the automatic operation control is suspended due to the driver's overriding operation, the current operation state is notified to the driver.

  The traveling control device 10, which is the core of the traveling control system 1 having the above-described devices, performs collision prevention control with an obstacle or the like, constant-speed traveling control, and the like based on input information and control information from the devices 15-22. Automatic driving control and the like are executed by coordinating follow-up travel control, lane keeping control, lane departure prevention control, other overtaking control and the like.

  In this automatic driving control, a route along which the vehicle travels is set based on traveling environment information acquired from image recognition of a captured image by a camera, radar, etc., and the steering system is automatically controlled to travel along this route. Also performs engine output control and brake control. At this time, in the control of the steering system, control is performed so as to achieve the target steering wheel angle θHt necessary to travel along the set route.

The path traveled by the vehicle can be set using known techniques without being limited to a specific technique. For example, when a route is set at the center of a lane recognized by image processing, the target steering wheel angle θHt can be calculated by the following equation (1). In equation (1), the steering angle for converging on the target value in a closed loop based on the deviation (xc-xv) between the current vehicle lateral position xv and the lane center position xc, and for feedforward control for turning of the curve A target steering wheel angle θHt is calculated by adding a steering angle based on the lane curvature y and a steering angle for causing the yaw angle θy to converge to the target value in a closed loop.
θHt = Gf · (xc−xv) + Gff · κ + Gy · θy (1)
However, Gf: feedback gain for the lateral position of the vehicle
Gff: feed forward gain
Gy: Feedback gain for yaw angle

Further, steering control to the target steering wheel angle θHt is executed as control to a target torque based on the deviation between the target steering wheel angle θHt and the actual steering wheel angle θH. Specifically, control to the target torque is executed as current control of the electric power steering motor via the steering control device 22. For example, electric power steering with driving current IM shown in the following equation (2) by PID control The motor is driven.
IM = Kv · (Kp · (θHt-θH) + Ki · ∫ (θHt-θH) dt + Kd · d (θHt-θH) / dt) (2)
However, Kv: motor voltage-current conversion coefficient
Kp: proportional gain
Ki: Integral gain
Kd: differential gain

  During such automatic driving control, when the override determination is made by the intervention of the driver, the driving mode is switched from the automatic driving to the manual driving. This operation mode switching is not the conventional operation switching which stops the automatic operation uniquely and switches to the manual operation when the overriding determination is made, but provides a plurality of operation modes which can be switched from the automatic operation, It is possible to switch from manual operation to manual operation in stages.

  For this reason, the traveling control device 10 determines, as a function related to switching between automatic operation and manual operation by overriding, the override determination unit 11 that determines which override condition of the plurality of operation modes is satisfied, and the override determination unit 11 And a driving mode switching unit 12 for switching the driving mode from the automatic driving according to the step of overriding determined in the above. Furthermore, in the present embodiment, an override determination threshold setting unit 11a is provided that varies the threshold when the override determination unit 11 determines overriding according to the traveling state.

  In the present embodiment, the override determination unit 11 determines which of the two operation modes of the operation modes A and B as described below corresponds to the operation mode of the override due to the driver's intervention. The operation mode A is a first operation mode in which cooperative control of automatic operation and manual operation is performed, and the operation mode B is a second operation mode in which manual operation with automatic operation suspended is permitted.

Operation mode A, which is the first operation mode, may further include a plurality of operation modes in which coordinated control is divided into a plurality of stages, in which case control of automatic operation in coordinated control will be described later. Set the gain in multiple steps.
<Operation mode A>
This operation mode takes into consideration the case where the degree of intervention in the driver's override is weak, and performs coordinated control of automatic operation and manual operation. For example, if the driver performs a manual operation temporarily and wants to leave it to the automatic operation by the system again, the manual control by the driver can be supported by the operation control by the system without switching to the manual operation uniquely. Operation mode of cooperative control.

For example, as shown in FIG. 2, when an object OB is present at a roadside inside a front turn while turning around a curve, in automatic driving, the own vehicle C and the object OB particularly interfere with running on the current route. If the vehicle is separated to such an extent that safety can be secured, traveling on the current route L is continued. At this time, as shown by a broken line, when the driver temporarily steers the vehicle OB so as to slightly deviate from the current route, by changing to the route L 'in the operation mode of the coordinated control, After passing through the object OB, it is possible to easily return to the automatic operation.
<Operation mode B>
It is similar to switching by the conventional override determination, and stops the automatic operation to allow the manual operation. In this operation mode B, the driver can operate by manual operation while stopping the control to the target steering angle by the system.

As shown in the following (1) and (2), it is determined by comparing at least one of the parameters representing the state of the steering system with the determination threshold, as shown in (1) or (2) below.
(1) Determination using steering torque The steering torque Tdrv of the driver is compared with the threshold values Th1 and Th2 (Th1 <Th2), and the driver performs relatively weak steering, and when the condition of Th2>Tdrv> Th1 is satisfied, coordination It is determined that the control is an override to the operation mode A. In addition, when the driver performs strong steering and the condition of Tdrv 成立 Th2 is satisfied, it is determined that manual operation is to be overridden to the operation mode B.
(2) Determination combining a plurality of parameters representing the state of the steering system As a plurality of parameters representing the state of the steering system, for example, steering torque, steering torque speed, steering angle, steering angular velocity, steering angular acceleration are assumed A two-dimensional map is created using the two parameters in, and the override determination of operation modes A and B is performed with reference to this map.

  In the two-dimensional map of override determination, as shown in FIG. 3, two parameters p and q among steering torque, steering torque speed, steering angle, steering angular velocity, and steering angular acceleration are arranged on the map axes of X and Y. Is created. Then, whether the operation mode to be overridden is the operation mode A or the operation mode B is determined by the position on the map specified by the parameters p and q.

  In FIG. 3, the region of x1 ≦ p ≦ x2 and y1 ≧ q and the region of −x1 ≧ p ≧ −x2 and −y1 ≦ q on the map of the X and Y axes are the override regions to the operation mode A. An area of x2 <p or y1 <q and an area of −x2> p or −y1> q are set as the overriding area RB to the operation mode B.

For example, using the steering torque as the parameter p of the map, if it is assumed that using the steering angle speed as a parameter q, a fast steering angle speed despite steering torque is small, when entering the region RB, the driver of the manual Since it is determined that the intention of the driving is clear, the automatic driving is stopped and it is determined that the driving mode B is the manual driving. Further, in moderate steering torque and the steering angle speed, when entering the region RA is willing to manual operation of the driver is transient, as potentially wants again, return to automatic operation , And override determination to the operation mode A in which automatic operation and manual operation are coordinated.

  The threshold value of this overriding determination is set by the overriding determination threshold setting unit 11a, and is varied according to the traveling state. That is, the determination thresholds Th1 and Th2 of the steering torque and the thresholds ± x1 and ± y1 for determining the areas RA and RB of the map are varied according to the conditions of the traveling state.

  As the conditions of the traveling state, there are, for example, a straight state and a turning state, a low vehicle speed state and a high vehicle speed state, etc. The threshold is changed according to these conditions, and coordinated control of automatic driving and manual driving is optimized. Ru. For example, in a state where the vehicle speed is low, the threshold value Th1 for determination on the steering torque is lowered to make it easier for the driver to intervene, and as the vehicle speed becomes higher, the threshold value Th2 is raised to make the driver harder to intervene.

  In addition, the threshold for judgment on the steering torque is lowered in the straight running state to make it easier for the driver to intervene, and in the turning driving state, the threshold for judgment is raised to make it difficult for the driver to intervene. It is possible to improve the sense of stability in steering and steering after the override. The straight state and the turning state can be determined based on the road surface state recognition by the camera, whether the steering angle exceeds a predetermined set value, and whether the yaw rate or the lateral acceleration exceeds a predetermined set value.

  The operation mode switching unit 12 switches the automatic operation, the operation mode A (coordinated control), and the operation mode B (manual operation) according to the determination result of the override by the override determination unit 11. In this case, in the cooperative control operation mode A, the control gain of the automatic operation is adjusted to give priority to the manual operation by the driver. The adjustment of the control gain of automatic driving may be performed as long as the steering reaction force of automatic driving for manual driving can be optimized by adjusting in the direction of reducing the steering torque by the system, and the target steering wheel angle θHt and driving current IM of the electric power steering motor The gain at the time of setting can be targeted.

  That is, in the operation mode A, gains (feedback gains Gf and Gy, feed forward gain Gff) at the time of calculating the target steering wheel angle θHt according to the above-mentioned equation (1) and driving of the electric power steering motor according to the equation (2) Assisting with the steering torque by the system while giving priority to the manual steering by the driver by adjusting and optimizing one or both of the gains (gains Kp, Ki, Kd of the PID control) when calculating the current IM Do.

  For example, by reducing the proportional gain Kp, integral gain Ki, and differential gain Kd of the PID control with respect to the drive current IM of the electric power steering motor, the steering torque for automatic driving is reduced by the driver. The steering torque of the automatic driving can be made into a size without a sense of incongruity with respect to the manual driving.

  However, when it is determined that safety can not be ensured by steering by the driver, the control gain of the automatic driving is not reduced but the control gain is increased. When operation mode A, which is the first operation mode, includes a multi-step mode, the control gain of automatic operation in coordinated control may be set in stages according to the degree of intervention of the driver, etc. good.

  Next, the program processing of the driving mode switching performed by the traveling control device 10 will be described using the flowchart shown in FIG.

  In this operation mode switching process, first, in the first step S101, it is determined whether or not the automatic operation control is being performed. 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 to determine the driving state such as straight running, turning, low vehicle speed traveling, high vehicle speed traveling and the like. Then, in step S103, a threshold value for overriding determination is set according to the traveling state.

  Next, the process proceeds to step S104, and it is determined whether the override condition is satisfied. For example, when the steering torque is determined using the steering torque, if the steering torque is equal to or less than the threshold Th1, it is determined that the override condition is not established, and the parameters of steering torque, steering torque speed, steering angle, steering angular velocity, and steering angular acceleration are When the two-dimensional map is referred to using, if the position in the map specified by the reference parameter is out of the area of the areas RA and RB, it is determined that the override condition is not satisfied.

  If it is determined in step S104 that the override condition is not established, the program is exited, and if it is determined that the override condition is established, the process proceeds to step S105. In step S105, it is checked whether the switching of the operation mode by the override is the operation mode A or the operation mode B. If switching to the operation mode A, cooperative control of automatic driving and manual driving is executed in step S106. If switching to the operation mode B, automatic driving is stopped in step S107 and steering by the driver is performed. Enable to follow the manual operation.

  As described above, in the present embodiment, the first operation mode for performing cooperative control between the automatic operation and the manual operation and the second operation mode for stopping the automatic operation and permitting the manual operation are provided. Since the first operation mode and the second operation mode are switched by the determination, it is possible to switch the operation mode smoothly and easily when switching from the automatic operation to the manual operation.

  Further, by providing a first operation mode intermediate between the automatic operation and the manual operation as the first stage of the override, it is possible to realize a state in which the intervention of the manual operation is permitted while the automatic operation is continued. That is, the driver can realize the state in which he / she intervenes and travels while sensing the control state by the automatic driving, and can realize the coordinated state in which the automatic driving and the manual driving are compatible.

  In addition, by providing the second operation mode in which the automatic operation is suspended and the manual operation is permitted as the second stage of the override, the automatic operation can be easily shifted to the manual operation switched to the manual operation. . Conversely, when the driver's intervention (override) is suspended, it is possible to quickly return to the original automatic driving state.

DESCRIPTION OF SYMBOLS 1 traveling control system 10 traveling control apparatus 11 override determination part 11a override determination threshold value setting part 12 driving mode switching part 22 steering control device

Claims (8)

In a travel control system of a vehicle that executes automatic driving control based on travel environment information of an environment in which the host vehicle travels and travel information of the host vehicle,
In the automatic operation control, there is an override condition to any of the first operation mode in which cooperative control of automatic operation and manual operation is performed and the second operation mode in which automatic operation is suspended and manual operation is permitted. An override determination unit that determines whether or not the condition is satisfied;
An operation mode switching unit that switches between automatic operation, the first operation mode, and the second operation mode according to the determination result of the override determination unit ;
The override determination unit sets the area of the first operation mode and the area of the second operation mode using two parameters representing the state of the steering system, and the area of the first operation mode and the area of the first operation mode A travel control system of a vehicle , wherein a threshold value of each parameter for determining a region of a second driving mode is varied according to a traveling condition as a determination threshold value for determining the override condition . The override determining unit uses a steering torque and a steering angular velocity as two parameters indicating the state of the steering system, and determines the area of the first operation mode and the area of the second operation mode. The vehicle travel control system according to claim 1 , wherein the determination threshold value and the determination threshold value of the steering angular velocity are varied according to the traveling state . The override determining unit sets the determination threshold of the steering torque for the area of the first operation mode and the determination threshold of the steering angular velocity as a threshold at which it is determined that the driver's intention for the manual operation is temporary. The determination threshold value of the steering torque to the area of the second operation mode and the determination threshold value of the steering angular velocity may be set as a threshold value determined that the driver's intention for the manual operation is clear. The travel control system of the vehicle according to 2. Wherein the determination threshold, running control system for a vehicle according to claim 1, wherein said override condition turning traveling state from straight running state, characterized in that the hard value established. Wherein the determination threshold, the vehicle running control system according to claim 1, characterized in that the vehicle speed becomes higher extent the override condition is a hard value established. The two parameters that represent the state of the steering system, the steering torque, the steering torque speed, steering angle, steering angular velocity, running control system for a vehicle according to claim 1, characterized in that any two of the steering angular acceleration . The travel control of a vehicle according to any one of claims 1 to 6, wherein when switched to the first operation mode, a control gain of automatic operation is adjusted to give priority to manual operation. system.   The travel control system for a vehicle according to claim 7, wherein the first operation mode includes a plurality of operation modes in which the control gains are set in a plurality of stages.

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