JP2021062803A - Device, method and program for contact avoidance support for vehicle - Google Patents

Abstract

To provide a contact avoidance support device capable of preventing vehicle behavior from becoming unstable, even when brake force changes during operation assist control.SOLUTION: A contact avoidance support device 1 for a vehicle 2 includes: a steering motor 20 for turning steered wheels 18 of the vehicle 2; a forward detection external sensor 10 for acquiring a relative position of an obstacle on a front side with respect to the vehicle 2; and a control device 15 for determining whether driving operation support for contact avoidance is required or not on the basis of the relative position, and for executing turning control for controlling a turning amount δ of the steering motor 20 in order to avoid contact with the obstacle, when determining that driving operation control is required. The control device 15 reduces the turning amount δ, if an increase in a brake operation amount Pb is detected by a brake sensor 24 during execution of the turning control.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to a vehicle contact avoidance support device, a vehicle contact avoidance support control method, and a vehicle contact avoidance support program for supporting contact avoidance between a vehicle and an obstacle in front of the vehicle.

A vehicle contact avoidance support device that supports contact avoidance with an obstacle in front of the vehicle is known (Patent Document 1). This vehicle contact avoidance support device requires a relative position detecting means for detecting the relative position between the vehicle and an obstacle, and determining the necessity of contact avoidance support based on the relative position to support contact avoidance. When it is determined, the steering assist control means for controlling the steering assist in the avoidance direction is provided, and the driving environment (for example, the road surface friction coefficient) affects the yaw moment applied to the vehicle by the output of the power steering device. In consideration of the above, control is performed so that the control device more preferably assists the contact avoidance.

Specifically, the vehicle contact avoidance support device includes a driving environment detecting means that affects the yaw moment acting on the vehicle and detects a driving environment in which the influence differs depending on the steering direction, such as a road surface friction coefficient. The steering assist control means corrects the steering assist force in the avoidance direction based on the traveling environment. For example, the steering assist control means determines the road surface friction coefficient of the left and right rear wheels, and when the road surface friction coefficient of the rear wheels in the avoidance direction intended by the driver is higher than the road surface friction coefficient of the other wheel, the steering angle of the steering wheel. And reduce the correction gain for correcting the target yaw rate set according to the vehicle speed. When the road friction coefficient of the rear wheels in the avoidance direction intended by the driver is lower than the road friction coefficient of the other, the steering assist control means reduces this correction gain. As a result, the steering assist force in consideration of the yaw moment is set, and contact avoidance is supported more appropriately.

Japanese Unexamined Patent Publication No. 2011-51510

However, in the vehicle contact avoidance support device described in Patent Document 1, steering assist control for contact avoidance is performed only when automatic brake control for contact avoidance is executed when steering assist is performed. , The change in braking force is not taken into consideration in the setting of operation assist force. Therefore, if the braking force changes during the operation assist control, the vehicle behavior may become unstable.

In view of such a background, it is an object of the present invention to prevent the vehicle behavior from becoming unstable even if the braking force changes during the operation assist control.

In order to solve such a problem, an embodiment of the present invention is a vehicle contact avoidance support device (1) that assists in avoiding contact with an obstacle in front of the vehicle, and is a steering wheel of the vehicle (2). A steering actuator (20) for steering (18), a relative position acquisition sensor (10) for acquiring the relative position of the obstacle with the vehicle, and the contact avoidance based on the relative position. When it is determined that the driving operation support is necessary and the driving operation support is necessary, the steering amount (δ) of the steering actuator is controlled so as to avoid contact with the obstacle. A control device (15) configured to execute steering control and a braking operation amount detection sensor (24) that detects a braking operation amount (Pb) by the driver with respect to the braking operation member (28) provided in the vehicle. ), The control device reduces the steering amount when an increase in the braking operation amount is detected during execution of the steering control (ST19, ST22).

According to this configuration, when the driver performs an operation to increase the braking operation amount, the steering control control device reduces the steering amount, so that the cornering force is reduced and the increase in the frictional force of the tire is suppressed. .. Therefore, the stability of vehicle behavior can be improved.

Further, in order to solve the above-mentioned problems, an embodiment of the present invention is a vehicle contact avoidance support device (1) that supports contact avoidance with an obstacle in front, and is a steering wheel of the vehicle (2). A steering actuator (20) for steering (18), a relative position acquisition sensor (10) for acquiring the relative position of the obstacle with the vehicle, and the contact avoidance based on the relative position. When it is determined that the driving operation support is necessary and the driving operation support is necessary, the steering amount (δ) of the steering actuator is controlled so as to avoid contact with the obstacle. A control device (15) configured to execute steering control and a braking operation amount detection sensor (24) that detects a braking operation amount (Pb) by the driver with respect to the braking operation member (28) provided in the vehicle. ), The control device increases the steering amount when a decrease in the braking operation amount is detected during execution of the steering control (ST19, ST22).

According to this configuration, when the driver performs an operation to reduce the braking operation amount, the control device increases the steering amount of the steering control, so that the cornering force is increased and the decrease in the frictional force of the tire is suppressed. .. Therefore, it is possible to reliably prevent the vehicle from coming into contact with an obstacle.

Preferably, a braking actuator (17) for applying a braking force to the vehicle is further provided, and the control device is configured to execute braking control for controlling the braking force of the braking actuator, and the driving operation. When it is determined that assistance is required, the control device determines whether or not the contact avoidance is possible only by the braking operation, and when the contact avoidance is possible only by the braking operation (ST11: Yes). When the braking control is executed (ST12), the contact avoidance is impossible only by the braking operation (ST11: No), and the driver performs a braking operation on the braking operation member (ST14: Yes), the rolling When steering control is executed (ST19, ST22), the contact avoidance is impossible only by the braking operation (ST11: No), and the driver does not perform the braking operation on the braking operation member (ST14: No). The braking control and the steering control are executed (ST15).

According to this configuration, when the contact can be avoided only by the braking operation, the contact can be avoided without changing the trajectory of the vehicle by the driving operation support by the braking control. When contact avoidance is not possible only by braking operation, contact is avoided by the minimum driving operation support by steering control if the braking operation member is operated, and braking control if the braking operation member is not operated. In addition, it is possible to provide driving operation support that reliably avoids contact by steering control.

Preferably, the braking actuator is configured to be able to distribute the braking force to a plurality of wheels included in the vehicle, and the control device distributes the braking force of the braking actuator to the plurality of wheels. When a change in the braking operation amount is detected during the execution of the steering control, the control device is caused by the increase / decrease in the steering amount. The braking force distribution control is executed so as to cancel the yaw moment of the vehicle (ST22).

According to this configuration, the control device executes braking force distribution control so that the yaw moment of the vehicle does not change even if the driver's braking operation amount changes, so that the vehicle avoids contact with obstacles. It is possible to more reliably avoid contact with obstacles of the vehicle.

Preferably, the control device determines whether or not the contact avoidance is possible only by the braking operation based on the relative position (ST11).

According to this configuration, it is possible to reliably determine whether or not contact avoidance is possible only by the braking operation by making a determination based on the relative position.

Preferably, the control device controls the steering amount so that the resultant force of the cornering force and the controlling / driving force does not exceed the friction circle of the tire during the execution of the steering control (ST19, ST22).

According to this configuration, the control device is within the range of the friction circle of the tire (within a predetermined upper limit value) regardless of whether the steering control is executed alone or both the braking control and the steering control are executed. By controlling the frictional force (combined force) generated on the tires, the stability of vehicle behavior can be improved.

In order to solve the above problem, an embodiment of the present invention is a vehicle contact avoidance support control method that supports contact avoidance with an obstacle in front, and is relative to the vehicle (2) of the obstacle. A relative position acquisition step (ST1) for acquiring a position, a necessity determination step (ST3) for determining the necessity of driving operation support for avoiding contact based on the relative position, and the driving operation support are required. When it is determined that there is (ST3: Yes), the amount of steering of the steering actuator (20) for steering the steering wheel (18) of the vehicle so as to avoid contact with the obstacle (ST3: Yes). A driving operation support step (ST4) for executing steering control for controlling δ) and a braking operation amount acquisition step for acquiring a braking operation amount (Pb) by the driver for the braking operation member (28) provided in the vehicle. Including (ST2), when an increase in the braking operation amount is detected during the execution of the steering control (ST19, ST22) in the driving operation support step, the steering amount is reduced.

According to this configuration, when the driver performs an operation to increase the braking operation amount, the steering amount in the steering control is reduced, so that the cornering force is reduced and the increase in the frictional force of the tire is suppressed. Therefore, the stability of vehicle behavior can be improved.

In order to solve the above problem, an embodiment of the present invention is a vehicle contact avoidance support program that supports contact avoidance with an obstacle in front of the vehicle, and the vehicle (15) of the obstacle is displayed on the computer (15). The relative position acquisition process (ST1) for acquiring the relative position with the vehicle 2), the necessity determination process (ST3) for determining the necessity of the driving operation support for avoiding the contact based on the relative position, and the operation. When it is determined that operation support is required (ST3: Yes), the steering actuator (20) for steering the steering wheel (18) of the vehicle so as to avoid contact with the obstacle. The driving operation support process (ST4) that executes the steering control that controls the steering amount (δ) and the braking that acquires the braking operation amount (Pb) by the driver for the braking operation member (28) provided in the vehicle. When the operation amount acquisition process (ST2) is executed and an increase in the braking operation amount is detected during the execution of the steering control (ST19, ST22) in the driving operation support process, the steering amount is reduced. Let me.

According to this configuration, when the driver performs an operation to increase the braking operation amount, the computer reduces the steering amount of the steering control, so that the cornering force is reduced and the increase in the frictional force of the tire is suppressed. Therefore, the stability of vehicle behavior can be improved.

As described above, according to the present invention, it is possible to prevent the vehicle behavior from becoming unstable even if the braking force changes during the operation assist control.

Block diagram of a vehicle equipped with a vehicle contact avoidance support device according to an embodiment The block diagram of the motion determination unit shown in FIG. Flow chart of contact avoidance support processing by the control device shown in FIG. Flow chart of driving operation support processing shown in FIG.

Hereinafter, embodiments of the vehicle contact avoidance support device according to the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram of a vehicle 2 equipped with a contact avoidance support device 1 for the vehicle 2 according to the embodiment. As shown in FIG. 1, the contact avoidance support device 1 is mounted on the vehicle 2 and assists the vehicle 2 in avoiding contact with an obstacle in front of the vehicle. The vehicle 2 is a four-wheeled vehicle, and is a propulsion device 3, a braking device 4, a steering device 5, a notification device 6, an operation amount sensor 7, a gripping state detection sensor 8, a vehicle state detection sensor 9, a front detection outside world sensor 10, and a rear. It has a side detection outside world sensor 11, a road surface condition acquisition sensor 12, and a control device 15. Each configuration constituting the system of the vehicle 2 is connected to each other so as to be able to transmit signals by a communication means such as CAN (Control Area Network).

The propulsion device 3 is a device that applies a driving force to the vehicle 2, and includes, for example, a power source and a transmission. The power source has at least one of an internal combustion engine such as a gasoline engine and a diesel engine and an electric motor. The propulsion device 3 includes a known driving force distribution device that distributes the generated driving force to the left and right wheels. The brake device 4 is a device that applies a braking force Fb to the vehicle 2, for example, four calipers 16 (brake calipers) that press pads against brake rotors provided on each wheel, and an electric cylinder that supplies hydraulic pressure to the calipers 16. The braking actuator 17 provided is included. Further, the braking actuator 17 includes a known braking force distribution device (for example, a VSA hydraulic unit) that distributes the braking force Fb generated by the braking device 4 to the four calipers 16. The brake device 4 may include a parking brake device that regulates the rotation of the wheels by a wire cable.

The steering device 5 is a device for changing the steering angle δ, which is the steering amount of the steering wheel 18 (front wheel). For example, a steering mechanism 19 provided with a rack and pinion mechanism for steering the steering wheel 18 and a steering device 19 for steering. It has a steering motor 20 which is a steering actuator for driving the steering mechanism 19. The steering device 5 may be an electric power steering in which the steering wheel 21 and the steering mechanism 19 are mechanically connected and the steering motor 20 functions as a steering assist motor. Alternatively, the steering device 5 may be a steer-by-wire that can take a state in which the steering mechanism 19 and the steering wheel 21 are not mechanically connected or are not connected.
The steering device 5 may further include a steering reaction force motor 22 that applies a steering reaction force to the steering wheel 21. The steering wheel 18 is steered by the steering motor 20 via the steering mechanism 19 according to the steering of the steering wheel 21, and the steering reaction force is applied to the steering wheel 21 according to the steering state of the steering wheel 18. It is imparted by the motor 22. The steering wheel 21 is a steering operation member that receives an operation on the steering device 5 by the driver.

The notification device 6 is a device for notifying the driver of information on driving and vehicle conditions by light, sound, and vibration. For example, a display device, a speaker, a seat, and a steering wheel 21 provided on an instrument panel or a steering wheel 21. It may be a vibrating device that vibrates the wheel. The vibrating device that vibrates the steering wheel 21 may be a steering motor 20 or a steering reaction force motor 22. The propulsion device 3, the brake device 4, the steering device 5, and the notification device 6 are controlled by the control device 15.

The operation amount sensor 7 is a sensor for detecting the driving operation amount of the driver, and has an accelerator sensor 23, a brake sensor 24, a steering angle sensor 25, and a steering torque sensor 26. The accelerator sensor 23 detects the accelerator depression amount Ap (accelerator opening degree), which is the amount of driving operation by the driver with respect to the accelerator pedal 27. The accelerator pedal 27 is a drive operation member that receives an operation on the propulsion device 3 by the driver. The brake sensor 24 is a braking operation amount detection sensor that detects the brake pedal effort Pb, which is the braking operation amount by the driver with respect to the brake pedal 28, from the brake fluid pressure. The brake pedal 28 is a braking operation member that receives an operation on the brake device 4 by the driver. The steering angle sensor 25 detects the steering angle θs, which is the steering angle of the steering wheel 21. The steering torque sensor 26 detects the steering torque Ts of the steering wheel 21.

The gripping state detection sensor 8 is a sensor for detecting the gripping state of the driver with respect to the steering wheel 21. For example, the position and angle of the driver's hand that is provided in front of the driver in the vehicle interior and grips the steering wheel 21. Has a camera that captures images. Further, the gripping state detection sensor 8 may have a piezoelectric sensor provided on the steering wheel 21 instead of the camera or in addition to the camera. When a piezoelectric sensor is provided instead of the camera, it is preferable that a plurality of piezoelectric sensors are provided over the entire circumference of the steering wheel 21 so that the position of the steering wheel 21 held by the driver's hand can be detected.

The vehicle state detection sensor 9 includes a vehicle speed sensor that detects the speed of the vehicle 2 and a yaw rate sensor that detects the angular velocity around the vertical axis of the vehicle 2. The yaw rate sensor is, for example, a gyro sensor. Further, the vehicle state detection sensor 9 may include an acceleration sensor that detects the acceleration of the vehicle 2, an orientation sensor that detects the direction of the vehicle 2, and the like.

The front detection outside world sensor 10 is a relative position acquisition sensor that detects an object such as an obstacle in front of the vehicle 2 and acquires a relative position between the vehicle 2 and the obstacle. The rear side detection outside world sensor 11 is a device that detects an object such as an obstacle on the side or the rear of the vehicle 2 and acquires a relative position between the vehicle 2 and the obstacle. The front detection outside world sensor 10 and the rear side detection outside world sensor 11 respectively capture sensors such as radar, lidar, and outside camera that detect electromagnetic waves and light from the periphery of the vehicle 2 to detect objects outside the vehicle. Including. The front detection outside world sensor 10 and the rear side detection outside world sensor 11 may be other devices that receive a signal from the outside of the vehicle and detect an object or the like outside the vehicle.

The radar emits radio waves such as millimeter waves around the vehicle 2 and captures the reflected waves to acquire the position (distance and direction) of the object. At least one radar may be attached to any part of the vehicle 2. Preferably, the front detection outside sensor 10 includes a front radar that irradiates radio waves toward the front of the vehicle 2, and the rear side detection outside sensor 11 includes a rear radar that irradiates radio waves toward the rear of the vehicle 2. More preferably, the rear side detection external sensor 11 includes a pair of left and right side radars that irradiate radio waves toward the side of the vehicle 2.

The rider irradiates the surroundings of the vehicle 2 with light such as infrared rays and captures the reflected light to acquire the position (distance and direction) of the object. At least one rider may be provided at any position on the vehicle 2. Preferably, the front detection outside world sensor 10 includes a front rider that irradiates light toward the front of the vehicle 2, and the rear side detection outside sensor 11 includes a rear rider that irradiates light toward the rear of the vehicle 2. More preferably, the rear side detection external sensor 11 includes a pair of left and right side riders that irradiate light toward the side of the vehicle 2.

The outside camera is the surroundings of the vehicle 2 including objects existing around the vehicle 2 (for example, peripheral vehicles and pedestrians), guardrails, curbs, walls, medians, road shapes, road markings drawn on the roads, and the like. To image. The external camera may be, for example, a digital camera using a solid-state image sensor such as a CCD or CMOS. At least one camera outside the vehicle may be provided at any position on the vehicle 2. Preferably, the front detection outside sensor 10 includes a front camera that images the front of the vehicle 2, and the rear side detection outside sensor 11 includes a rear camera that images the rear of the vehicle 2. More preferably, the rear side detection external sensor 11 includes a pair of side cameras that image the left and right sides of the vehicle 2. The out-of-vehicle camera may be, for example, a stereo camera.

The road surface condition acquisition sensor 12 is a sensor for acquiring the condition of the traveling road surface of the vehicle 2. The road surface condition acquisition sensor 12 includes, for example, a wheel speed sensor used for acquiring a road surface friction coefficient μ. A wheel speed sensor is provided on each wheel and is used to estimate the road surface friction coefficient μ. The operation amount sensor 7, the gripping state detection sensor 8, the vehicle state detection sensor 9, the front detection outside world sensor 10, the rear side detection outside world sensor 11, and the road surface state acquisition sensor 12 output the detection / acquisition result to the control device 15.

The control device 15 includes an arithmetic processing unit (CPU) and a storage device (memory such as ROM and RAM), and is an electronic control device (ECU) composed of a computer configured to execute various processes necessary for contact avoidance support. Is. The control device 15 is configured to execute various processes, that is, the arithmetic processing unit (CPU) constituting the control device 15 reads necessary data and application software from the storage device (memory), and according to the software. It means that it is programmed to execute the predetermined arithmetic processing. The control device 15 executes various vehicle controls for avoiding contact, that is, driving operation support processing, by executing predetermined arithmetic processing on the CPU according to a program. The control device 15 may be configured as one hardware, or may be configured as a unit composed of a plurality of hardware.

As functional units, the control device 15 includes a gripping state recognition unit 31, an override determination unit 32, a vehicle state determination unit 33, a front obstacle recognition unit 34, a collision risk determination unit 35, a free space recognition unit 36, and a rear side obstacle. It has an object recognition unit 37, a road surface friction coefficient estimation unit 38, and a motion determination unit 39. At least a part of each functional unit of the control device 15 may be realized by hardware such as LSI, ASIC, FPGA, or may be realized by a combination of software and hardware.

The gripping state recognition unit 31 identifies the driver's steering gripping state based on the detection result (grasping state) of the gripping state detection sensor 8. Specifically, the gripping state recognition unit 31 is a two-handed gripping state in which the driver is gripping the steering wheel 21 with both hands, a one-handed gripping state in which the driver is gripping the steering wheel 21 with one hand, and driving. It identifies which of the steering wheel gripping states the person is not gripping the steering wheel 21.

The override determination unit 32 operates while the control device 15 is executing the contact avoidance support control (during system activation) based on the accelerator depression amount Ap, the brake depression force Pb, the steering steering angle θs and its angular velocity, and the steering gripping state. Judge whether or not there is an operation intervention (override) of the person. The override determination unit 32 determines the accelerator override, the brake override, and the steering override as the driver's operation intervention.

The own vehicle state determination unit 33 determines (estimates) the predicted traveling trajectory of the own vehicle based on the vehicle speed, yaw rate, and the like. The front obstacle recognition unit 34 recognizes the front obstacle based on the detection / acquisition result of the front detection external sensor 10, and also recognizes the front obstacle attribute (vehicle, pedestrian, structure, etc.) and relative position. Recognize (distance and direction from own vehicle), relative speed, etc. (hereinafter referred to as forward obstacle information). The collision risk determination unit 35 determines that the vehicle is in front of the vehicle based on the predicted traveling trajectory of the vehicle determined by the vehicle condition determination unit 33 and the front obstacle information recognized by the front obstacle recognition unit 34. Determine the risk of collision or contact with an object. Specifically, the collision risk determination unit 35 determines whether or not there is a possibility of collision with an obstacle in front of the own vehicle, the collision direction when there is a possibility of collision, TTC (Time To Collection: collision margin time), and the lap rate ( (Value obtained by dividing the amount of overlap with the front obstacle that collides when the own vehicle travels on the track by the total width of the own vehicle) and the like are determined.

The free space recognition unit 36 recognizes a white line (road marking on the road surface), an oncoming vehicle, a roadside structure, a pedestrian, a road shoulder, etc. in front based on the detection / acquisition result of the front detection external world sensor 10, and free space. Recognize (empty space that your vehicle can occupy). The rear side obstacle recognition unit 37 recognizes adjacent lanes, rear and side objects, roadside structures, and the like based on the detection / acquisition results of the rear side detection external sensor 11. Further, the rear side obstacle recognition unit 37 uses the attributes (vehicles, pedestrians, structures, etc.) and relative positions (distance and direction from the own vehicle) of the rear and side objects (hereinafter referred to as rear side obstacles). Etc.), relative speed, etc. (hereinafter referred to as rear side obstacle information).

The road surface friction coefficient estimation unit 38 estimates the road surface friction coefficient μ based on the acquisition result of the road surface state acquisition sensor 12. For example, the road surface friction coefficient estimation unit 38 responds to the difference in wheel speed between the left and right front wheels and the left and right rear wheels when the control device 15 operates the braking actuator 17 to generate braking force Fb on the left and right rear wheels. Estimate the road surface friction coefficient μ. The road surface friction coefficient estimation unit 38 may estimate the road surface friction coefficient μ by using another known method.

The motion determination unit 39 includes an identification result of the gripping state recognition unit 31 (hereinafter, simply referred to as a gripping state), a determination result of the override determination unit 32 (override), and a determination result of the collision risk determination unit 35 (hereinafter, referred to as a collision risk determination). , The identification result of the free space recognition unit 36 (hereinafter referred to as free space information), the rear side obstacle among the identification results of the rear side obstacle recognition unit 37, and the estimation result of the road surface friction coefficient estimation unit 38 (hereinafter referred to as the road surface friction coefficient estimation unit 38). Based on the road surface friction coefficient μ), the operations of the propulsion device 3, the brake device 4, the steering device 5, and the notification device 6 are controlled in order to support the avoidance of contact with the front obstacle.

That is, the motion determination unit 39 determines the necessity of driving operation support for contact avoidance based on the collision risk determination with the front obstacle based on the relative position of the front obstacle, and the driving operation support is required. When it is determined that there is, the instruction value for the propulsion device 3, the brake device 4, the steering device 5, and the notification device 6 is calculated by a predetermined calculation so as to avoid contact with the front obstacle, and the instruction signal is output.

FIG. 2 is a block diagram of the motion determination unit 39 shown in FIG. As shown in FIG. 2, the motion determination unit 39 includes a braking avoidance limit distance calculation unit 41, a braking force instruction calculation unit 42, a contact avoidance trajectory calculation unit 43, a steering angle instruction calculation unit 44, and forward contact due to steering avoidance. It has a danger determination unit 45, a rear contact danger determination unit 46 for avoiding steering, and a final instruction calculation unit 47.

The braking avoidance limit distance calculation unit 41 is a relative distance required to avoid contact of the vehicle 2 with a front obstacle by a predetermined braking operation of the vehicle 2 based on the collision danger determination and the road surface friction coefficient μ. Calculate the limit distance. The braking force instruction calculation unit 42 calculates the deceleration obtained based on the braking avoidance limit distance and the vehicle speed, and the braking force Fb obtained by multiplying the deceleration by the mass of the vehicle 2, and controls the braking device 4 to be generated. The indicated value of the power Fb is calculated.

The contact avoidance trajectory calculation unit 43 calculates the contact avoidance trajectory to be taken in order to avoid the contact of the vehicle 2 with the front obstacle by the predetermined steering operation of the vehicle 2 based on the collision risk determination and the road surface friction coefficient μ. .. The steering angle instruction calculation unit 44 calculates an instruction value of the steering angle δ required for the steering operation according to the contact avoidance trajectory.

The forward contact danger determination unit 45 due to steering avoidance with the front obstacle by the steering operation for taking the contact avoidance trajectory based on the contact avoidance trajectory calculated by the contact avoidance trajectory calculation unit 43 and the free space information. When avoiding contact (that is, avoiding steering), the risk of the vehicle coming into contact with other forward obstacles is determined. The rear contact danger determination unit 46 due to steering avoidance is based on the contact avoidance trajectory calculated by the contact avoidance trajectory calculation unit 43 and the rear side obstacle information, and when the vehicle avoids steering, the own vehicle moves to the rear and side. Determine the risk of contact with one of the obstacles.

The final instruction calculation unit 47 sets the instruction value of the driving force for avoiding contact by the driving operation, the instruction value of the braking force Fb for avoiding contact by the braking operation, and the steering angle δ for avoiding contact by the steering operation. Judgment of the necessity of driving operation support for contact avoidance based on the indicated value, the contact danger judgment with the front obstacle by steering avoidance, and the contact danger judgment with the rear side obstacle by steering avoidance. .. Further, the final instruction calculation unit 47 selects the control to be executed when it is determined that the driving operation support is necessary, and sets the final instruction value for the propulsion device 3, the brake device 4, the steering device 5, and the notification device 6. Various controls that calculate and output instruction signals (drive instruction, braking instruction, steering instruction, alarm instruction) are executed.

Specifically, the final instruction calculation unit 47 executes the driving force distribution control for distributing the driving force generated by the propulsion device 3 to the left and right wheels with respect to the driving force distribution device of the propulsion device 3. The final instruction calculation unit 47 executes braking force control that generates a predetermined braking force Fb for the braking actuator 17 of the braking device 4 regardless of the brake pedaling force Pb of the brake pedal 28. Further, the final instruction calculation unit 47 executes braking force distribution control for distributing the predetermined braking force Fb generated by the braking actuator 17 to the calipers 16 provided on each wheel to the braking force distribution device of the braking actuator 17. Hereinafter, the combination of the driving force distribution control and the braking force distribution control is referred to as a control / driving force distribution control. The final instruction calculation unit 47 executes steering angle control for the steering motor 20 of the steering device 5 to realize a predetermined steering angle δ regardless of the steering angle θs. The final instruction calculation unit 47 executes notification control for causing the notification device 6 to notify the driver.

Next, the procedure of contact avoidance support by the control device 15 configured in this way will be described. FIG. 3 is a flowchart of contact avoidance support processing by the control device 15 shown in FIG. The control device 15 repeats the contact avoidance support process shown in FIG. 3 at a predetermined control cycle. As shown in FIG. 3, in the contact avoidance support process, the control device 15 acquires the relative position between the vehicle 2 and the front obstacle based on the detection / acquisition result of the front detection external sensor 10. (Step ST1). Further, the control device 15 is a sensor that acquires detection / acquisition values of various sensors such as an operation amount sensor 7, a gripping state detection sensor 8, a vehicle state detection sensor 9, a rear side detection outside world sensor 11, and a road surface state acquisition sensor 12. The value acquisition process is performed (step ST2).

Subsequently, the control device 15 performs a necessity determination process for determining the necessity of driving operation support for contact avoidance, at least based on a collision risk determination with the front obstacle based on the relative position of the front obstacle. (Step ST3). When it is determined in step ST3 that the driving operation support is unnecessary, the control device 15 ends this routine and repeats the above procedure. On the other hand, when it is determined in step ST3 that driving operation support is required, the control device 15 executes the driving operation support process (step ST4).

FIG. 4 is a flowchart of the driving operation support process shown in FIG. The control device 15 repeats the driving operation support process shown in FIG. 4 at a predetermined control cycle. As shown in FIG. 4, in the driving operation support process, the control device 15 determines whether or not contact with the front obstacle can be avoided only by the braking operation (step ST11). Specifically, the control device 15 determines whether or not contact with the front obstacle can be avoided only by the braking operation based on the front obstacle information including the relative position. When it is determined that contact avoidance is possible only by the braking operation (ST11: Yes), the control device 15 outputs the braking force Fb (for example, the maximum braking force according to the road surface friction coefficient μ) to be generated in the braking device 4 as an instruction signal. Braking control is executed (step ST12), and the above procedure is repeated. When it is determined that the contact cannot be avoided only by the braking operation (ST11: No), the control device 15 calculates the contact avoidance trajectory to be taken in order to avoid the contact by the steering operation (step ST13).

Subsequently, the control device 15 determines whether or not there is a driver's braking operation (step ST14). Specifically, the control device 15 determines whether or not the brake pedal force Pb detected by the brake sensor 24 exceeds a predetermined operation threshold value, and when the brake pedal force Pb exceeds the operation threshold value, the driver It is determined that there is a brake operation, and when the brake pedal effort Pb is equal to or less than the operation threshold value, it is determined that there is no brake operation by the driver. When it is determined that the driver does not operate the brake (ST14: No), the control device 15 executes braking control for outputting an instruction signal to the brake device 4 and steering control for outputting an instruction signal to the steering device 5 (step). ST15), the above procedure is repeated. In the steering control in step ST15, the control device 15 calculates the steering angle δ of the steering wheel 18 required to drive the vehicle 2 along the contact avoidance trajectory calculated in step ST13 as an instruction value.

At this time, the control device 15 controls the steering angle δ of the steering wheel 18 so that the resultant force of the cornering force and the controlling / driving force does not exceed the friction circle of the tire. The tire friction circle is the maximum friction drawn around the tire contact patch with the product of the friction coefficient between the tire and the road surface (road surface friction coefficient μ estimated by the road surface friction coefficient estimation unit 38) and the tire contact patch as the radius. It is a circle that shows power. Therefore, the radius of the friction circle becomes smaller as the road surface friction coefficient μ becomes smaller. On the other hand, when the ground contact load of the tire moves from the rear wheel to the front wheel due to braking, the radius of the friction circle of the rear wheel becomes small and the friction circle of the front wheel becomes large.

When it is determined in step ST14 that the driver has a brake operation (Yes), the control device 15 determines the expected deceleration estimated to be generated by the driver in the brake device 4 based on the brake pedal effort Pb. Calculate (step ST16). Subsequently, the control device 15 calculates the cornering force capable of generating the four tires and the steering angle δ of the steering wheel 18 corresponding to the cornering force in consideration of the expected deceleration (step ST17). Also at this time, the control device 15 calculates the cornering force and the steering angle δ corresponding thereto so that the resultant force of the cornering force and the controlling / driving force does not exceed the friction circle of the tire.

However, as described above, the ground contact load of the tire moves from the rear wheels to the front wheels due to braking, but there is a time lag between the generation of the braking force Fb and the movement of the ground contact load, and at the moment when the tire generates the braking force Fb. The frictional force of the front wheels of the steering wheel 18 may exceed the friction circle. Therefore, the control device 15 reduces the expected reduction in the friction circle based on the front wheel contact load based on the specifications of the vehicle 2 without considering that the radius of the friction circle of the front wheels increases due to the movement of the ground load due to the expected deceleration. The cornering force that can be generated and the steering angle δ corresponding to the cornering force are calculated in consideration of the front-rear force (friction force used by the driver's braking operation) according to the speed.

Next, the control device 15 determines whether or not the vehicle 2 can travel on the contact avoidance track calculated in step ST13 based on the steering angle δ calculated in step ST17 (step ST18). When it is determined that the vehicle 2 can travel on the contact avoidance track (ST18: Yes), the control device 15 outputs a steering control that outputs an instruction signal to the steering device 5 so that the vehicle 2 travels on the contact avoidance track. Is executed (step ST19), and the above procedure is repeated.

When it is determined in step ST18 that the vehicle 2 cannot travel on the contact avoidance track (No), the control device 15 contacts when the vehicle 2 travels under the steering angle δ calculated in step ST17. The insufficient yaw moment that is insufficient to travel on the avoidance track is calculated (step ST20). Subsequently, the control device 15 calculates the distribution of the control / driving force (usually the braking force Fb generated by the driver's braking operation) required to generate the insufficient yaw moment (step ST21). Then, the control device 15 outputs the steering angle δ calculated in step ST17 as an instruction signal to the steering device 5, and the brake device 4 or the brake device 4 or the control device 15 for executing the distribution of the control / driving force calculated in step ST21. Control / driving force distribution control that outputs an instruction signal to the propulsion device 3 is executed (step ST22), and the above procedure is repeated.

When it is determined in step ST3 of FIG. 1 that driving operation support is required (Yes), the control device 15 determines in step ST11 of FIG. 2 whether or not contact avoidance is possible only by the braking operation. However, when contact avoidance is possible only by braking operation (ST11: Yes), braking control is executed (ST12). As a result, contact can be avoided without changing the trajectory of the vehicle 2. When contact avoidance is impossible only by braking operation in step ST11 (No) and there is a braking operation by the driver for the brake pedal 28 (ST14: Yes), the control device 15 executes steering control in steps ST19 and ST22. To do. As a result, contact can be avoided with the minimum driving operation support by the steering control. When contact avoidance is impossible only by braking operation in step ST11 (No) and there is no braking operation by the driver for the brake pedal 28 (ST14: No), the control device 15 executes braking control and steering control in step ST15. To do. As a result, driving operation support that reliably avoids contact is provided by braking control and steering control.

In step ST11, the control device 15 makes a determination based on the relative position, and thereby it is possible to reliably determine whether or not contact avoidance is possible only by the braking operation.

If the driver starts the braking operation while repeatedly executing the above procedure, the determination in step ST14 changes from No to Yes. Therefore, the control device 15 performs the braking control performed in step ST15. It stops, and in step ST19, only steering control is continued. As a result, contact can be avoided with the minimum driving operation support by the steering control.

Further, if the driver enhances the brake operation while repeatedly executing this procedure, that is, if an increase in the brake pedal force Pb is detected, the expected deceleration calculated in step ST16 becomes large. Since the cornering force calculated in step ST17 and the steering angle δ of the steering wheel 18 corresponding to the cornering force become smaller, the control device 15 reduces the steering angle δ in the steering control executed in step ST22. Further, even in the steering control for traveling the vehicle 2 along the contact avoidance track, which is executed in step ST19, if the frictional force of the steering wheel 18 is close to the friction limit, the steering wheel is at the moment when the braking force Fb increases. The frictional force of 18 can exceed the friction circle. Therefore, when an increase in the brake pedal force Pb is detected, the control device 15 reduces the steering angle δ in order to reduce the cornering force.

In this way, when the control device 15 detects an increase in the brake pedal force Pb while the steering control is being executed (ST19, ST22), the steering angle δ is reduced, so that the cornering force is reduced and the frictional force of the tire is reduced. By suppressing the increase, the stability of vehicle behavior is enhanced.

On the contrary, if the driver reduces the brake operation while repeatedly executing this procedure, that is, if a decrease in the brake pedal force Pb is detected, the expected deceleration calculated in step ST16 becomes large. Since the cornering force calculated in step ST17 and the steering angle δ of the steering wheel 18 corresponding to the cornering force become smaller, the control device 15 reduces the steering angle δ in the steering control executed in step ST22. Further, even in the steering control executed in step ST19, when a decrease in the brake pedal force Pb is detected, a margin is generated in the frictional force of the steering wheel 18, so that the control device 15 steers to increase the cornering force. Increase the angle δ.

In this way, when the control device 15 detects a decrease in the brake pedal force Pb while the steering control is being executed (ST19, ST22), the steering angle δ is increased, so that the cornering force is increased and the frictional force of the tire is increased. By suppressing the decrease, the vehicle 2 is surely prevented from coming into contact with the obstacle.

Further, a change in the brake pedal force Pb was detected while the procedure was repeatedly executed in a state where the contact avoidance trajectory could not be traveled under the possible steering angle δ (ST18: No). In this case, since the insufficient yaw moment calculated in step ST20 changes, the control device 15 changes the distribution of the control / driving force required for traveling on the contact avoidance trajectory in step ST21. That is, in step ST22, the control device 15 executes the control / driving force distribution control so as to cancel the yaw moment of the vehicle 2 caused by the increase / decrease in the steering angle δ that can be implemented by the steering control.

In this way, the control device 15 executes the braking force distribution control so that the yaw moment of the vehicle 2 does not change even if the driver's brake pedal force Pb changes, so as to avoid contact with an obstacle. The vehicle 2 is driven, and contact with the obstacle of the vehicle 2 is more reliably avoided.

Further, during the execution of the steering control in steps ST15, ST19 and ST22, the control device 15 controls the steering angle δ so that the resultant force of the cornering force and the controlling / driving force does not exceed the friction circle of the tire. ing. In this way, the control device 15 is within the range of the friction circle of the tire (predetermined) regardless of whether the steering control is executed only (ST19) or both the braking control and the steering control are executed (ST15, ST19). By controlling the frictional force (coupling force) generated in the tire so that it falls within the upper limit), the stability of the vehicle behavior is enhanced.

As described above, the vehicle contact avoidance support control method according to the present embodiment includes the relative position acquisition step (ST1) for acquiring the relative position of the obstacle with the vehicle 2 and the contact avoidance based on the relative position. Vehicle 2 so as to avoid contact with obstacles in the necessity determination step (ST3) for determining the necessity of driving operation support and when it is determined that driving operation support is necessary (ST3: Yes). The driver operates by acquiring the driving operation support step (ST4) that executes the steering control that controls the steering angle δ of the steering motor 20 for steering the steering wheel 18 and the detection / acquisition values of various sensors. Includes a braking operation amount acquisition step (ST2) for acquiring the brake pedal effort Pb. In the driving operation support step (ST4), when an increase in the brake pedal force Pb is detected during the execution of the steering control (ST19, ST22), the steering angle δ is reduced.

With this configuration, when the driver operates to increase the brake pedal effort Pb, the steering angle δ in the steering control in steps ST19 and ST22 decreases, so that the cornering force decreases and the increase in tire friction force is suppressed. Will be done. Therefore, the stability of vehicle behavior is improved.

On the other hand, in the vehicle contact avoidance support control method according to the present embodiment, as described above, in the driving operation support step (ST4), a decrease in the brake pedal force Pb is detected during the execution of the steering control (ST19, ST22). If so, the steering angle δ is increased. With this configuration, when the driver operates to reduce the brake pedaling force Pb, the cornering force is increased and the decrease in the frictional force of the tire is suppressed. Therefore, the vehicle 2 is surely prevented from coming into contact with the obstacle.

The vehicle contact avoidance support program stored in the storage device (memory) of the control device 15 according to the present embodiment acquires the relative position of the obstacle to the vehicle 2 by the control device 15 which is a computer. When it is determined that the process (ST1), the necessity determination process (ST3) for determining the necessity of the driving operation support for contact avoidance based on the relative position, and the driving operation support are necessary (ST3: Yes). ), Driving operation support process (ST4) that executes steering control that controls the steering angle δ of the steering motor 20 for steering the steering wheel 18 of the vehicle 2 so as to avoid contact with obstacles. And the braking operation amount acquisition process (ST2) for acquiring the brake pedal force Pb by the driver. Further, the program reduces the steering angle δ in the control device 15 when an increase in the brake pedal force Pb is detected during the execution of the steering control (ST19, ST22) in the driving operation support process (ST4).

With this configuration, when the driver operates to increase the brake pedaling force Pb, the cornering force is reduced and the increase in the frictional force of the tire is suppressed. Therefore, the stability of vehicle behavior is improved.

On the other hand, the program according to the present embodiment increases the steering angle δ in the control device 15 when a decrease in the brake pedal force Pb is detected during the execution of steering control (ST19, ST22) in the driving operation support process. .. With this configuration, when the driver operates to reduce the brake pedaling force Pb, the cornering force is increased and the decrease in the frictional force of the tire is suppressed. Therefore, the vehicle 2 is surely prevented from coming into contact with the obstacle.

Although the description of the specific embodiment is completed above, the present invention can be widely modified without being limited to the above embodiment. For example, the specific configuration, arrangement, quantity, procedure, etc. of each member or portion can be appropriately changed as long as it does not deviate from the gist of the present invention. On the other hand, not all of the components shown in the above embodiments are indispensable, and they can be appropriately selected.

1 Contact avoidance support device 2 Vehicle 10 Front detection outside world sensor (relative position acquisition sensor)
15 Control device (computer)
17 Braking actuator 18 Steering wheel 20 Steering motor (steering actuator)
24 Brake sensor (braking operation amount detection sensor)
28 Brake pedal (braking operation member)
Pb Brake pedaling force (braking operation amount)
δ Steering angle (steering amount)

Claims (8)

A vehicle contact avoidance support device that assists in avoiding contact with obstacles in front of the vehicle.
A steering actuator for steering the steering wheel of the vehicle and
A relative position acquisition sensor that acquires the relative position of the obstacle with respect to the vehicle,
The necessity of driving operation support for avoiding contact is determined based on the relative position, and when it is determined that the driving operation support is necessary, the steering is steered so as to avoid contact with the obstacle. A control device configured to perform steering control that controls the steering amount of the actuator, and
It is provided with a braking operation amount detection sensor that detects the braking operation amount by the driver with respect to the braking operation member provided in the vehicle.
The control device is a contact avoidance support device for a vehicle, characterized in that when an increase in the braking operation amount is detected during execution of the steering control, the steering amount is reduced. A vehicle contact avoidance support device that assists in avoiding contact with obstacles in front of the vehicle.
A steering actuator for steering the steering wheel of the vehicle and
A relative position acquisition sensor that acquires the relative position of the obstacle with respect to the vehicle,
The necessity of driving operation support for avoiding contact is determined based on the relative position, and when it is determined that the driving operation support is necessary, the steering is steered so as to avoid contact with the obstacle. A control device configured to perform steering control that controls the steering amount of the actuator, and
It is provided with a braking operation amount detection sensor that detects the braking operation amount by the driver with respect to the braking operation member provided in the vehicle.
The control device is a vehicle contact avoidance support device, which increases the steering amount when a decrease in the braking operation amount is detected during execution of the steering control. A braking actuator for applying a braking force to the vehicle is further provided.
The control device is configured to perform braking control that controls the braking force of the braking actuator.
When it is determined that the driving operation support is necessary, the control device determines whether or not the contact avoidance is possible only by the braking operation, and determines whether or not the contact avoidance is possible.
When the contact avoidance is possible only by the braking operation, the braking control is executed.
When the contact avoidance is impossible only by the braking operation and the driver performs a braking operation on the braking operation member, the steering control is executed.
Claim 1 or claim, wherein the braking control and the steering control are executed when the contact avoidance is impossible only by the braking operation and the driver does not perform the braking operation on the braking operation member. Item 2. The vehicle contact avoidance support device according to item 2. The braking actuator is configured to be able to distribute the braking force to a plurality of wheels included in the vehicle.
The control device is configured to execute braking force distribution control that distributes and generates the braking force of the braking actuator to a plurality of the wheels.
When a change in the braking operation amount is detected during the execution of the steering control, the control device controls the braking force distribution so as to cancel the yaw moment of the vehicle caused by the increase or decrease in the steering amount. 3. The vehicle contact avoidance support device according to claim 3. The vehicle contact avoidance support device according to claim 3 or 4, wherein the control device determines whether or not the contact avoidance is possible only by the braking operation based on the relative position. Claims 1 to claim that the control device controls the steering amount so that the resultant force of the cornering force and the controlling / driving force does not exceed the friction circle of the tire during the execution of the steering control. Item 5. The vehicle contact avoidance support device according to any one of Items 5. It is a contact avoidance support control method for vehicles that supports contact avoidance with obstacles in front.
A relative position acquisition step for acquiring the relative position of the obstacle with respect to the vehicle, and
A necessity determination step for determining the necessity of driving operation support for avoiding contact based on the relative position, and a necessity determination step.
Steering that controls the steering amount of the steering actuator for steering the steering wheels of the vehicle so as to avoid contact with the obstacle when it is determined that the driving operation support is necessary. The driving operation support step to execute the control and
Including a braking operation amount acquisition step of acquiring a braking operation amount by the driver for the braking operation member provided in the vehicle.
A vehicle contact avoidance support control method, characterized in that, when an increase in the braking operation amount is detected during execution of the steering control in the driving operation support step, the steering amount is reduced. A vehicle contact avoidance support program that assists in avoiding contact with obstacles in front of you.
On the computer
Relative position acquisition processing for acquiring the relative position of the obstacle with respect to the vehicle, and
Judgment processing for determining the necessity of driving operation support for avoiding contact based on the relative position, and
Steering that controls the steering amount of the steering actuator for steering the steering wheels of the vehicle so as to avoid contact with the obstacle when it is determined that the driving operation support is necessary. Driving operation support processing to execute control and
The braking operation amount acquisition process for acquiring the braking operation amount by the driver for the braking operation member provided in the vehicle is executed.
A vehicle contact avoidance support program characterized in that when an increase in the braking operation amount is detected during execution of the steering control in the driving operation support process, the steering amount is reduced.

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