JP7218626B2 - Vehicle travel control device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle travel control system that avoids a collision with an obstacle present in the traveling direction of the vehicle when there is a sudden accelerator operation at low vehicle speed.

Conventionally, obstacle sensors such as radar sensors, ultrasonic sensors, and camera sensors detect obstacles in the direction in which the vehicle is traveling, and when there is a possibility of collision with an obstacle, pre-collision control is performed to avoid the collision. A vehicle running control device that executes (PCS control) is known. One of the conventional vehicle travel control devices (hereinafter referred to as the "conventional device") is that when the vehicle is stopped or traveling at an extremely low speed, it is difficult for the monocular camera sensor to detect obstacles. Even if there is, it is determined whether or not pre-collision control is executed based on obstacle information detected by the ultrasonic sensor and information on obstacles detected by the monocular camera sensor in the past (for example, Patent Document 1).

JP 2017-43173 A

By the way, in a situation where the vehicle is stopped or traveling at a very low speed and the obstacle is also stopped or moving at a very low speed, the relative speed between the vehicle and the obstacle is zero or very low. When an obstacle is detected in such a situation, the Time To Collision (TTC) becomes a very large value. Furthermore, in such a situation, if the accelerator pedal is erroneously depressed, the PCS control is not executed until the vehicle accelerates and the TTC falls below a predetermined threshold. Therefore, there is a delay from when the accelerator pedal is operated to when the PCS control starts to limit the driving force.

The present invention has been made to address the above problems. That is, one of the objects of the present invention is to control the vehicle without delay even if the accelerator pedal is strongly depressed while the vehicle is stopped or traveling at a very low speed and an obstacle is detected. To provide a vehicle travel control device capable of starting control for limiting the driving force of a vehicle, thereby reducing the possibility of contact between the vehicle and an obstacle.

A travel control device of the present invention (hereinafter also referred to as "the device of the present invention") includes a plurality of wheels (WFL, WFR, WRL, WRR) and at least front wheels (WFL, WFR) and/or wheels of the plurality of wheels. Alternatively, it is applied to a vehicle (SV) provided with a driving device (64) that applies driving force to rear wheels (WRL, WRR) and a braking device (73) that applies braking force to the plurality of wheels.

The device of the present invention includes obstacle sensors (20, 30), an accelerator pedal operation amount sensor (51), a vehicle speed sensor (53), and a control section (50). The obstacle sensor detects an obstacle existing in a predetermined detection area around the vehicle and acquires obstacle detection information, which is information about the detected obstacle. The accelerator pedal operation amount sensor detects an accelerator pedal operation amount (AP). The vehicle speed sensor detects the vehicle speed (SPD) of the vehicle.

The control unit calculates a relative distance (Drel) between the vehicle and the obstacle based on the acquired obstacle detection information, and determines that the relative distance is equal to or less than a predetermined first threshold distance (Dth1). is satisfied, the detected vehicle speed is equal to or less than a predetermined threshold speed (SPDth) and the accelerator pedal operation amount (AP) is equal to or greater than a predetermined threshold operation amount (APth) is established, the driving force is limited, and when the condition that the relative distance is equal to or less than a predetermined second threshold distance (Dth2) that is equal to or less than the predetermined first threshold distance is established, the configured to increase braking force;

According to the device of the present invention, when the vehicle is stopped or is traveling at an extremely low speed while an obstacle is detected and the accelerator pedal operation amount is equal to or greater than a predetermined threshold operation amount. , limits the drive power generated by the drive based on the relative distance between the vehicle and the obstacle rather than the relative velocity. Therefore, according to the device of the present invention, the driving force of the vehicle can be limited without delay compared to the case where the control is performed based on the relative speed between the vehicle and the obstacle. It is possible to provide a vehicle travel control device capable of reducing the possibility of contact with the vehicle.

In the above description, in order to facilitate understanding of the invention, the reference numerals used in the embodiments are attached to the configurations of the invention corresponding to the embodiments in parentheses. It is not intended to be limited to the defined embodiments. Objects, other features and attendant advantages of the present invention will be readily understood from the description of embodiments of the present invention described with reference to the following drawings.

FIG. 1 is a schematic system configuration diagram of a vehicle running control device according to an embodiment of the present invention. FIG. 2 is an explanatory diagram of the mounting positions of the radar sensor and camera sensor shown in FIG. 1 and the detectable area of each sensor on the xy plane. FIG. 3 is an explanatory diagram of detectable areas on the xz plane of the radar sensor and camera sensor shown in FIG. FIG. 4 is a diagram showing changes in the vehicle speed, the accelerator cut control execution flag, the low acceleration brake control execution flag, and the brake hold control execution flag with respect to the relative distance between the vehicle and the target. FIG. 5 is a lookup table that defines the relationship between the relative speed and the relative distance for starting accelerator cut control. FIG. 6 is a lookup table that defines the relationship between the relative speed and the relative distance at which low acceleration brake control is started. FIG. 7 is a flowchart showing a "low-speed pre-collision control routine" executed by the CPU of the pre-collision control ECU shown in FIG.

(composition)
FIG. 1 is a schematic system configuration diagram of a travel control device (hereinafter also referred to as "this control device") 10 according to an embodiment of the present invention. The control device 10 is mounted on a vehicle SV.

The control device 10 includes a radar sensor 20, a camera sensor 30, a target detection ECU 40, a pre-collision control ECU 50, an engine ECU 60, a brake ECU 70 and an alarm ECU 80.

The radar sensor 20 has a radar wave transmitting/receiving section 21 and an information processing section 22 . The radar wave transmitting/receiving unit 21 emits millimeter wave band electromagnetic waves (hereinafter also referred to as "millimeter waves"), and detects three-dimensional objects (hereinafter also referred to as "targets") existing within the radiation range. Receives millimeter waves (reflected waves) reflected by The radar wave transmitting/receiving unit 21 may be a radar wave transmitting/receiving unit (including laser radar) that uses electromagnetic waves in frequency bands other than the millimeter wave band.

Based on the reflection point information including the phase difference between the radiated (transmitted) millimeter wave and the received reflected wave, the attenuation level of the reflected wave, and the time from transmission to reception of the millimeter wave, The distance between the vehicle SV and the target (approximately the center position of the target), the direction (azimuth) of the target with respect to the vehicle SV, the speed of the target with respect to the vehicle SV, and the like are detected. The information processing unit 22 groups the "plurality of reflection points" that are close to each other, and recognizes the group of the grouped reflection points (hereinafter referred to as "reflection point group") as one target. The information processing unit 22 assigns a target ID to the recognized target as identification information for specifying/identifying the target. The information processing unit 22 uses an arbitrary point (specific reflection point) in the reflection point group to calculate radar sensor detection information. The radar sensor detection information includes the longitudinal distance Dfx of the target, the azimuth θp of the target with respect to the vehicle SV, the relative velocity Vfx between the vehicle SV and the target, and the like. Further, the radar sensor 20 (information processing unit 22) outputs laser sensor detection information to the target object detection ECU 40 every time a certain period of time elapses.

A radar sensor 20 is provided in front of the vehicle SV in order to acquire information on targets present mainly in the area ahead of the vehicle SV. More specifically, as shown in FIG. 2, the radar sensor 20 is arranged at the vehicle width direction center position of the front bumper FB of the vehicle SV. The area where the radar sensor 20 can detect a target (detectable area) is, as shown in FIG. It is a fan-shaped area extending to the right boundary line RBL1 in the direction to the left and to the left boundary line LBL1 in the left direction.

The detection axis CL1 coincides with the vehicle front-rear axis FR. The "magnitude of the angle formed between the detection axis CL1 and the right boundary line RBL1" and the "magnitude of the angle formed between the detection axis CL1 and the left boundary line LBL1" are each θ1. Therefore, the central angle of the sector, which is the detectable area of the radar sensor 20, is (2·θ1). Note that the radar sensor 20 may be composed of a plurality of radar sensors arranged at different positions of the vehicle SV (for example, front, right front, and left front of the vehicle SV).

The camera sensor 30 includes a stereo camera 31 that captures an image of the front of the vehicle SV and an image processing device 32 that processes the image captured by the stereo camera 31 . As shown in FIG. 2, the stereo camera 31 is arranged inside the passenger compartment of the front window. The detectable area of the camera sensor 30 extends from the "detection axis CSL extending forward from the center position of the front window of the vehicle SV in the vehicle width direction" to the right to the right boundary line RCBL and to the left to the left boundary line LCBL. It is a fan-shaped area. The detection axis CSL coincides with the vehicle longitudinal axis FR of the vehicle SV. The "magnitude of the angle formed between the detection axis CSL and the right boundary line RCBL" and the "magnitude of the angle formed between the detection axis CSL and the left boundary line LCBL" are each θ2. Therefore, the angle of view of the camera sensor 30 is (2·θ2).

As shown in FIG. 3, the vertical detectable area of the radar sensor 20 is a fan-shaped area from the upper boundary line UBL1 to the lower boundary line DBL1. Furthermore, the vertical detectable area of the camera sensor 30 is a fan-shaped area from the upper boundary line UCBL to the lower boundary line DCBL.

The stereo camera 31 transmits an image signal representing a photographed image to the image processing device 32 every time a certain period of time elapses. The image processing device 32 determines whether or not there is a target in the imaging area (detectable area) based on the received image signal. When the image processing device 32 determines that a target exists in the imaging area, it calculates the position of the target and identifies the type of the target (automobile, motorcycle, pedestrian, etc.) by well-known pattern matching. The position of the target is specified by the direction (azimuth) of the target with respect to the vehicle SV and the distance between the target and the vehicle SV. Further, the image processing device 32 extracts (specifies) the left end point (left end point) and the right end point of the target, and obtains information about the positions of these end points with respect to the vehicle SV.

The camera sensor 30 receives information indicating the position of the target (generally the center position of the target, for example, the center between the left end point and the right end point of the target) and information indicating the type of target after a certain period of time. It is output to the target object detection ECU 40 each time. Furthermore, the camera sensor 30 detects the speed of the target with respect to the vehicle SV (relative speed) to the target object detection ECU 40 every time a certain period of time elapses.

Target information detected by the radar sensor 20 and camera sensor 30 (the distance between the approximate center position of the target and the vehicle SV, the direction (azimuth) of the approximate center position of the target relative to the vehicle SV, the target relative to the vehicle SV including information indicating relative velocity and type of target) is hereinafter referred to as "target information". Information detected by the radar sensor 20 is preferentially used for the relative distance Drel and the relative velocity Vrel between the target and the vehicle SV, and information detected by the camera sensor 30 is preferentially used for the azimuth of the target. used as

The target detection ECU 40 is electrically connected to the radar sensor 20 and camera sensor 30 . The target detection ECU 40 stores target information acquired from the radar sensor 20 and the camera sensor 30 in a memory (RAM) within the target detection ECU 40 . ECU is an abbreviation of electronic control unit, and is an electronic control circuit having a microcomputer including CPU, ROM, RAM, backup RAM (or non-volatile memory), interface I/F, etc. as main components. The CPU implements various functions described later by executing instructions (routines) stored in a memory (ROM).

A pre-collision control ECU (hereinafter also referred to as "PCSECU") 50 is electrically connected to a target detection ECU 40, an engine ECU 60, a brake ECU 70, and an alarm ECU 80 via CAN (Controller Area Network) communication so that data can be exchanged with each other. It is Therefore, the PCSECU 50 can control the motion state of the vehicle SV in cooperation with the engine ECU 60 and the brake ECU 70 while referring to the target information recorded in the memory (RAM) within the target detection ECU 40 .

The PCSECU 50 is electrically connected to the following sensors and receives detection signals or output signals from these sensors. Note that each sensor may be connected to an ECU other than the PCSECU 50 . In that case, the PCSECU 50 receives the detection signal or output signal of the sensor via CAN from the ECU to which the sensor is connected.

The accelerator pedal operation amount sensor 51 detects the operation amount (accelerator opening) of an accelerator pedal 51a of the vehicle SV, and outputs a signal representing the accelerator pedal operation amount AP. A brake pedal operation amount sensor 52 detects an operation amount of a brake pedal 52a of the vehicle SV and outputs a signal representing the brake pedal operation amount BP. The vehicle speed sensor 53 detects the traveling speed (vehicle speed) of the vehicle SV and outputs a signal representing the vehicle speed SPD.

The engine ECU 60 is connected to the engine actuator 61 . The engine actuator 61 includes a throttle valve actuator that changes the opening of a throttle valve of a spark ignition/gasoline fuel injection internal combustion engine (E/G) 62 . The engine ECU 60 can change the drive torque generated by the internal combustion engine 62 by driving the engine actuator 61 . A drive torque generated by the internal combustion engine 62 is transmitted to a left front wheel WFL and a right front wheel WFR (hereinafter also referred to as “front wheels WF”) via a transmission 63 . Therefore, the engine ECU 60 can control the driving force of the vehicle SV by controlling the engine actuator 61 to change the acceleration state (acceleration). Hereinafter, the engine actuator 61, the internal combustion engine 62 and the transmission 63 are also referred to as "drive device 64".

The drive torque generated by the internal combustion engine 62 may be transmitted to the left rear wheel WRL and the right rear wheel WRR (hereinafter also referred to as "rear wheel WR"), or may be transmitted to the front wheel WF. and the rear wheels WR. If the vehicle SV is a hybrid vehicle, the engine ECU 60 can control the driving force generated by one or both of the "internal combustion engine and electric motor" as the driving source. Furthermore, when the vehicle SV is an electric vehicle, the engine ECU 60 can control the driving force generated by the electric motor as the driving source.

The brake ECU 70 is electrically connected to the brake actuator 71 . The brake actuator 71 is provided between a master cylinder (not shown) that pressurizes the hydraulic oil by depressing the brake pedal 52a, and a friction brake mechanism 72 provided on the left front wheel WFL, the right front wheel WFR, the left rear wheel WRL, and the right rear wheel WRR. It is provided in the hydraulic circuit. The brake actuator 71 adjusts the hydraulic pressure supplied to the wheel cylinder built in the brake caliper 72b of the friction brake mechanism 72 according to the instruction from the brake ECU 70. The brake pad is pressed against the brake disc 72a by operating the wheel cylinder with the hydraulic pressure. As a result, a frictional braking force is generated. Therefore, the brake ECU 70 can control the braking force of the vehicle SV by controlling the brake actuator 71 to change the acceleration state (deceleration, that is, negative acceleration).

The alarm ECU 80 is electrically connected to the buzzer 81 and the indicator 82 . The alarm ECU 80 causes the buzzer 81 to output "an alarm sound for drawing the driver's attention to a target that is highly likely to collide with the vehicle SV" in response to an instruction from the PCSECU 50. FIG. Furthermore, the alarm ECU 80 causes the display 82 to display a mark (for example, a warning lamp) to call attention in response to an instruction from the PCSECU 50 .

(Outline of operation)
When the accelerator pedal 51a is operated and the vehicle SV is rapidly accelerated while the vehicle speed of the vehicle SV is zero or extremely low, the control device 10 detects a target in front of the vehicle SV. By controlling the driving force and braking force, contact/collision between the vehicle SV and the target is avoided. The procedure will be described below.

In FIG. 4, the horizontal axis is the distance (relative distance) Drel between the vehicle SV and a target (in this example, a pedestrian) present in front of the vehicle SV. FIG. 4 shows, in order from the top, the vehicle speed SPD of the vehicle SV, the accelerator cut control execution flag, the low acceleration brake control execution flag, and the brake hold control execution flag. When the value of each execution flag is "1", it means that the corresponding control is being executed, and when the value is "0", it means that the corresponding control is not being executed. represents. In other words, FIG. 4 shows changes in the execution state of the running control of the vehicle SV by the control device 10 with respect to the relative distance Drel.

As shown in FIG. 4, the vehicle speed SPD is 0 km/h when the relative distance Drel between the vehicle SV and the target is 5 m. That is, the vehicle SV is stopped. At this time, when the driver of the vehicle SV operates the accelerator pedal 51a, the vehicle SV approaches the pedestrian. Furthermore, when the driver depresses the accelerator pedal 51a greatly when the relative distance Drel reaches D1 (when the accelerator pedal operation amount AP becomes equal to or greater than a predetermined threshold operation amount APth), the PCSECU 50 performs accelerator cut control. to run. Accelerator cut control is control that does not transmit the driving force generated by the internal combustion engine 62 to the drive wheels.

More specifically, when the relative distance Drel reaches D1 and the accelerator cut control execution flag is changed from "0" to "1", the engine ECU 60 changes the state of the transmission 63 according to the instruction from the PCSECU 50. to neutral state. As a result, the driving force generated by the internal combustion engine 62 is not transmitted to the driving wheels WF regardless of the accelerator pedal operation amount AP.

When the accelerator pedal 51a is greatly depressed, the accelerator pedal operation amount AP increases (an acceleration request is generated). Therefore, the engine ECU 60 increases the driving torque of the internal combustion engine 62 according to the instruction from the PCSECU 50 . Therefore, the vehicle speed SPD increases once. After that, when the accelerator pedal operation amount AP becomes equal to or greater than a predetermined threshold operation amount APth, the engine ECU 60 immediately executes accelerator cut control. Therefore, the vehicle speed SPD does not increase abruptly, but increases relatively gently.

Accelerator cut control is executed when the relative distance Drel is equal to or less than a first threshold distance Dth1 and the accelerator pedal actuation amount AP is equal to or greater than a predetermined threshold actuation amount APth. The first threshold distance Dth1 is obtained by applying the actually acquired relative velocity Vrel to a lookup table MapDth1(Vrel) that defines the relationship between the relative velocity Vrel between the vehicle SV and the target and the first threshold distance Dth1. is calculated by

As shown in FIG. 5, the first threshold distance Dth1 is set to a constant value (eg, 5 m) with respect to the relative speed Vrel. Acceleration cut control is control for preventing the vehicle SV from suddenly starting or accelerating even though there is a target in front of the vehicle SV. Therefore, the first threshold distance Dth1 is set to a constant value regardless of the relative speed Vrel in order to secure a sufficient distance to avoid collision between the vehicle SV and the target.

In this example, since the relative distance D1 was 5 m or less when the accelerator pedal operation amount AP became equal to or greater than the predetermined threshold operation amount APth, the condition for executing the accelerator cut control was established at this time, and the accelerator cut control was executed. The flag is changed from "0" to "1". Note that the lookup table MapDth1(Vrel) and a lookup table to be described later are determined in advance by simulations, experiments, etc., and are stored in the ROM within the PCSECU 50. FIG.

After that, when the relative distance Drel reaches D2, the brake ECU 70 brakes the vehicle SV at a predetermined relatively low acceleration (deceleration) according to an instruction from the PCSECU 50 . More specifically, when the low acceleration brake control execution flag is changed from "0" to "1", the brake ECU 70 operates the brake actuator so that the deceleration of the vehicle SV becomes a predetermined relatively low deceleration. 71. The predetermined relatively low deceleration is set, for example, to any value between 0.1 and 0.2 gravitational acceleration (m/s ² ). Note that the accelerator cut control is continued even if the relative distance Drel becomes less than or equal to D2.

By the way, the second threshold distance Dth2 (=D2), which is the relative distance when the low acceleration brake control execution flag is changed from "0" to "1", expresses the relationship between the relative speed Vrel and the second threshold distance Dth2. It is calculated by applying the actually obtained relative velocity Vrel to a defined lookup table MapDth2(Vrel). As shown in FIG. 6, the second threshold distance Dth2 is set to 2 m when the relative speed Vrel is extremely low (0 km/h to 7 km/h), and is set to 2 m when the relative speed Vrel is low (10 km/h to 15 km/h). h), set to 3m. Furthermore, when the relative speed Vrel is between 7 km/h and 10 km/h, the second threshold distance Dth2 is set to be longer between 2 m and 3 m as the relative speed Vrel increases (linearly interpolated ).

That is, in the example shown in FIG. 4, the relative speed Vrel is 7 km/h or more and less than 15 km/h when the relative distance becomes D2 (=Dth2). In a situation where the relative speed Vrel is 15 km/h or more, the PCSECU 50 executes pre-crash (pre-collision) control known to those skilled in the art. "Known pre-collision control" is collision avoidance control performed based on the collision margin time TTC between the vehicle SV and the target. It is disclosed in publications and the like.

After that, when the relative distance Drel becomes D3, the brake ECU 70 ends the low acceleration brake control and starts the brake hold control in accordance with the instruction from the PCSECU 50 .

The brake hold control is braking control for stopping the vehicle SV. ) to brake the vehicle SV at a deceleration (for example, 0.6 gravitational acceleration). The execution condition of the brake hold control is that the vehicle speed SPD remains equal to or less than the predetermined threshold speed SPDth for a predetermined time tel after the vehicle speed SPD shifts from a state higher than the predetermined threshold speed SPDth to a state equal to or less than the predetermined threshold speed SPDth. It is supposed to be established when For example, the predetermined threshold speed SPDth is set to 4 km/h, and the predetermined time tel is set to 0.7 sec.

When the condition for executing brake hold control is satisfied, the brake ECU 70 starts brake hold control in accordance with an instruction from the PCSECU 50 . From the execution condition of the brake hold control, the vehicle speed SPD of the vehicle SV when the brake hold control is started is 4 km/h or less. For example, when a vehicle SV traveling at 4 km/h is decelerated by 0.6 gravitational acceleration, the vehicle SV advances about 1 m after 1.85 seconds and stops (when the vehicle speed SPD is zero). Become). Therefore, in FIG. 4, the vehicle speed SPD of the vehicle SV becomes zero when the relative distance Drel becomes D4. That is, the vehicle SV stops at a distance D4 in front of the pedestrian by brake hold control. This avoids contact/collision between the vehicle SV and pedestrians. Note that the values of the first threshold distance Dth1, the second threshold distance Dth2, the threshold speed SPDth, the predetermined time tel, etc. are merely examples, and the control device is not limited by these numerical values.

(Actual operation)
Next, the actual operation of the control device 10 will be described.

The CPU of the PCSECU 50 (hereinafter also simply referred to as "CPU") executes a "low-speed pre-collision control routine" shown in the flowchart of FIG. It's becoming

The CPU starts processing from step 700 at a predetermined timing, proceeds to step 710, and acquires target object information and vehicle state information. The vehicle state information is, for example, the own vehicle speed (the vehicle speed SPD of the vehicle SV), the accelerator pedal operation amount AP, and the like.

Next, the CPU proceeds to step 720 and determines whether or not the vehicle speed SPD is equal to or less than a predetermined threshold speed SPDth. If the vehicle speed SPD is greater than the predetermined threshold speed SPDth, the CPU makes a "No" determination at step 720, proceeds directly to step 795, and terminates this routine. That is, in this case, pre-collision control at low speed is not executed.

On the other hand, if the vehicle speed SPD is equal to or less than the predetermined threshold speed SPDth, the CPU determines "Yes" in step 720 and proceeds to step 730 to determine whether the accelerator pedal operation amount AP is equal to or greater than the predetermined threshold operation amount APth. determine whether The predetermined threshold operation amount APth is a relatively large operation amount such that the vehicle SV suddenly starts or accelerates. If the accelerator pedal operation amount AP is less than the predetermined threshold operation amount APth, the CPU makes a "No" determination in step 730, proceeds directly to step 795, and terminates this routine. That is, in this case, it is determined that the possibility of a collision with the target is low (more specifically, it is determined that it is not an erroneous operation by the driver), and low-speed pre-collision control is not executed.

On the other hand, when the accelerator pedal operation amount AP is equal to or greater than the predetermined threshold operation amount APth, the CPU determines "Yes" in step 730, proceeds to step 740, and the target to be controlled is within the first threshold distance Dth1. determines whether it exists in In other words, it is determined whether or not the relative distance Drel to the target is equal to or less than the first threshold distance Dth1.

If the target to be controlled exists within the calculated first threshold distance Dth1, the CPU determines "Yes" in step 740, proceeds to step 750, and executes accelerator cut control. At this time, the value of the accelerator cut control flag is changed from "0" to "1".

Next, the CPU proceeds to step 760 and determines whether or not the relative distance Drel to the target to be controlled is within the second threshold distance Dth2. If the relative distance to the target to be controlled is within the second threshold distance Dth2, the CPU determines "Yes" in step 760, proceeds to step 770, and executes low acceleration brake control. At this time, the value of the low acceleration brake control flag is changed from "0" to "1".

Next, the CPU proceeds to step 780 and determines whether or not the conditions for starting the brake hold control are satisfied. If the conditions for starting the brake hold control are not met, the CPU makes a "No" determination in step 780, directly proceeds to step 795, and once terminates this routine. That is, in this case, the CPU continues the low acceleration brake control.

On the other hand, if the conditions for starting the brake hold control are satisfied, the CPU makes a "Yes" determination in step 780 and proceeds to step 790 to end the low acceleration brake control and start the brake hold control. That is, in this case, the CPU increases the deceleration of the vehicle SV. At this time, the value of the low acceleration brake control flag is changed from "1" to "0" and the value of the brake hold control flag is changed from "0" to "1". Next, the CPU proceeds to step 795 and once terminates this routine.

As described above, the vehicle travel control device according to the embodiment of the present invention includes obstacle sensors (radar sensor 20 and camera sensor 30), accelerator pedal operation amount sensor 51, vehicle speed sensor 53, control unit (PCSECU) 50; The obstacle sensors 20 and 30 detect obstacles existing in a predetermined detection area around the vehicle SV, and obtain obstacle detection information, which is information about the detected obstacles. An accelerator pedal operation amount sensor 51 detects an accelerator pedal operation amount AP. Vehicle speed sensor 53 detects vehicle speed SPD of vehicle SV.

The control unit 50 calculates the relative distance Drel between the vehicle SV and the obstacle based on the acquired obstacle detection information, and the condition that the relative distance Drel is equal to or less than a predetermined first threshold distance Dth1 is established. , when the detected vehicle speed SPD is equal to or less than a predetermined threshold speed SPDth and the accelerator pedal operation amount AP is equal to or more than a predetermined threshold operation amount APth, the driving force is limited and the relative The braking force is increased when the condition that the distance Drel is equal to or less than a predetermined second threshold distance Dth2, which is equal to or less than a predetermined first threshold distance, is established.

According to this, when the driver depresses the accelerator pedal 51a greatly while the vehicle SV is stopped or traveling at an extremely low speed, if there is an obstacle in the traveling direction of the vehicle SV, The driving force and braking force of the vehicle SV are controlled based on the relative distance Drel between the vehicle SV and the obstacle. Therefore, according to this control device, the control for limiting the driving force of the vehicle can be started without delay as compared with the control based on the relative speed Vrel between the vehicle SV and the obstacle.

<Modification>
It should be noted that the present invention is not limited to the above embodiments, and various modifications can be adopted within the scope of the present invention.

In this embodiment, the radar sensor 20 and camera sensor 30 are arranged to detect obstacles in front of the vehicle SV. However, a radar sensor and/or a camera sensor may be further arranged behind the vehicle SV, and accelerator cut control, low acceleration brake control and brake hold control may be executed even when the vehicle SV is backing up. As a result, even when the vehicle SV suddenly starts or accelerates rearward, collision or contact between the vehicle SV and an obstacle present behind the vehicle SV can be avoided.

In the above embodiment, the predetermined first threshold distance Dth1 at which the accelerator cut control is executed is set to be constant with respect to the relative speed Vrel. may be defined so that the higher the

In the above embodiment, the accelerator cut control is executed first, and then the low acceleration brake control is executed. However, the accelerator cut control and the low acceleration brake control may be executed at the same time. That is, the predetermined first threshold distance Dth1 and the predetermined second threshold distance Dth2 may be set to the same value.

In the above-described embodiment, the radar sensor 20 employs a radar that transmits and receives electromagnetic waves in the millimeter wave band. For example, it may be a laser radar).

Furthermore, in the above embodiment, regarding the distance and relative velocity between the target and the vehicle SV, the information detected by the radar sensor 20 is prioritized, and regarding the azimuth of the target, priority is given to the information detected by the camera sensor 30. was However, these relative distances, relative velocities, and target azimuths may be detected by either the radar sensor 20 or the camera sensor 30, or only one of the radar sensor 20 and the camera sensor 30 is provided. may

Although the radar sensor 20 is used as one of the obstacle sensors in the above embodiment, an ultrasonic sensor may be used instead.

DESCRIPTION OF SYMBOLS 10... Travel control apparatus 20... Radar sensor 30... Camera sensor 40... Target object detection ECU 50... Pre-collision control ECU (PCSECU) 51... Accelerator pedal operation amount sensor 51a... Accelerator pedal 53... Vehicle speed sensor , 60... Engine ECU, 64... Driving device, 70... Brake ECU, 73... Braking device, SV... Vehicle, WFL, WFR, WRL, WRR... Wheels.

Claims (1)

a plurality of wheels;
a driving device that applies driving force to at least the front wheels and/or the rear wheels among the plurality of wheels;
a braking device that applies a braking force to the plurality of wheels;
Applies to vehicles with
an obstacle sensor that detects an obstacle present in a predetermined detection area around the vehicle and acquires obstacle detection information that is information about the detected obstacle;
an accelerator pedal operation amount sensor that detects an accelerator pedal operation amount;
a vehicle speed sensor that detects the vehicle speed of the vehicle;
acquiring a relative distance and relative speed between the vehicle and the obstacle based on the acquired obstacle detection information;
When the condition that the relative distance is equal to or less than a predetermined first threshold distance is satisfied, the detected vehicle speed is equal to or less than a predetermined threshold speed and the accelerator pedal operation amount is equal to or greater than a predetermined threshold operation amount. When the condition is established, the driving force is limited, and the relative distance is equal to or less than a predetermined second threshold distance, which is equal to or less than the predetermined first threshold distance. , a control unit configured to execute low-acceleration brake control for increasing the braking force;
In a vehicle travel control device comprising
The control unit
The first threshold distance is set to a constant value regardless of the relative speed,
setting the second threshold distance to be longer as the relative speed is higher in a range smaller than the first threshold distance;
configured as
Furthermore, the control unit
During execution of the low acceleration brake control, after the detected vehicle speed transitions from a state higher than the threshold speed to a state equal to or lower than the threshold speed, the detected vehicle speed is kept lower than or equal to the threshold speed for a predetermined time. state, brake hold control is executed to further increase the braking force so that the vehicle decelerates at a deceleration greater than the deceleration in the low acceleration brake control. ,
A vehicle running control device.

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