JP2011183983A - Vehicle controller - Google Patents

Abstract

An object of the present invention is to provide a vehicle control device that prevents a driver from feeling uncomfortable when a driver performs a brake operation during vehicle speed control.
A vehicle control device for controlling a vehicle speed of a host vehicle, wherein the brake operation detecting unit detects a brake operation of a driver of the host vehicle, and when the driver of the host vehicle performs a brake operation during the vehicle speed control. When the pedaling force in the brake operation is less than or equal to the threshold value, the release of the vehicle speed control is prohibited, and the vehicle speed control is switched to the brake operation different from the normal vehicle speed control. Control switching means for switching from vehicle speed control to normal vehicle speed control is provided.
[Selection] Figure 2

Description

  The present invention relates to a vehicle control device that controls the speed of a host vehicle.

  In ACC [Adaptive Cruise Control] control, when there is a preceding vehicle ahead of the host vehicle, inter-vehicle distance control (preceding vehicle following control) is performed so that the inter-vehicle distance from the preceding vehicle becomes the target inter-vehicle distance. When the vehicle does not exist, constant speed control is performed so that the vehicle speed of the host vehicle becomes the target vehicle speed. When the driver performs a brake operation during such ACC control, the ACC control is canceled and a braking force corresponding to the driver's brake operation is generated.

  In the system described in Patent Literature 1, the vehicle speed limit in the travel lane of the host vehicle is determined, and the smaller vehicle speed is selected from the set vehicle speed set by the driver and the following vehicle speed set according to the distance between the preceding vehicle and the vehicle. Then, the cruise control vehicle speed is determined, and the vehicle speed control is performed using the lower vehicle speed of the limit vehicle speed and the cruise control vehicle speed as the target vehicle speed. In particular, in this system, when no preceding vehicle is detected, the vehicle speed during curve driving is calculated based on the set vehicle speed set by the driver and the curve vehicle speed corresponding to the curve shape of the road, and the vehicle speed of the limit vehicle speed and the vehicle speed during curve driving are calculated. The lower vehicle speed is set as the target vehicle speed.

JP 2009-208661 A

  In the ACC control, in the case of curve driving, a target vehicle speed lower than usual is set as in the above-described system, and a deceleration braking force is generated. At this time, if the driver feels that the vehicle speed of the host vehicle is high or that the vehicle is too close to the preceding vehicle, the driver may perform a light brake operation. When the ACC control is released by this braking operation, the deceleration braking force by the ACC control is lost, and only a small braking force corresponding to a light braking operation is applied to the host vehicle. As a result, the braking force acting on the host vehicle is reduced, and the driver feels uncomfortable.

  Accordingly, an object of the present invention is to provide a vehicle control device that prevents a driver from feeling uncomfortable when the driver performs a brake operation during vehicle speed control.

  The vehicle control device according to the present invention is a vehicle control device that controls the vehicle speed of the host vehicle, the brake operation detecting means for detecting the brake operation of the driver of the host vehicle, and the driver of the host vehicle during the vehicle speed control. When the pedaling force in the brake operation is below the threshold when the vehicle is operated, the vehicle speed control is prohibited from being released, the vehicle speed control is switched to the brake operation different from the normal vehicle speed control, and the driver of the host vehicle finishes the brake operation. In this case, a control switching means for switching from vehicle speed control during brake operation to normal vehicle speed control is provided.

  This vehicle control device performs vehicle speed control by constant speed control, inter-vehicle distance control, or the like. In the vehicle control device, the brake operation detection means detects the brake operation by the driver (for example, whether or not the brake operation is performed and the pedaling force (stepping amount, stepping speed, stepping time, etc.) in the brake operation). When a brake operation by the driver is detected by the brake operation detection means during the vehicle speed control, the vehicle control device determines whether or not the pedal effort in the brake operation is less than or equal to a threshold by the control switching means. In this case, the release of the vehicle speed control is prohibited, and the vehicle speed control at the time of brake operation, which is different from the normal vehicle speed control, is switched. As described above, when a weak braking operation with a pedaling force equal to or less than the threshold is performed, the vehicle speed control corresponding to the time of the brake operation is continuously performed without releasing the vehicle speed control, and the deceleration braking force by the vehicle speed control is applied to the host vehicle. Continue to act. Then, when it is detected by the brake operation detecting means that the brake operation by the driver is lost during the vehicle speed control during the brake operation, the vehicle control device changes the vehicle speed control during the brake operation from the vehicle speed control to the normal vehicle speed control by the control switching means. Switch. In this vehicle control device, even when the driver performs a brake operation during the vehicle speed control, the deceleration braking force by the vehicle control can be continued by continuously performing the vehicle speed control during the brake operation, and the driver feels uncomfortable. I do not receive it.

  In the present invention, even when the driver performs a brake operation, the driver does not feel uncomfortable by continuously performing the vehicle speed control during the brake operation.

It is a block diagram of the ACC system which concerns on this invention. It is a flowchart which shows the flow of the control switching process corresponding to brake operation in ACC ECU which concerns on 1st Embodiment. It is a flowchart which shows the flow of the risk determination process in the flowchart of FIG.2 and FIG.5. It is a flowchart which shows the flow of the ACC cancellation | release will determination process in the flowchart of FIG.2 and FIG.5. It is a flowchart which shows the flow of the control switching process corresponding to brake operation in ACC ECU which concerns on 2nd Embodiment. It is a flowchart which shows the flow of the control switching process corresponding to the curve recognition in ACC ECU which concerns on 3rd Embodiment.

  Hereinafter, an embodiment of a vehicle control device according to the present invention will be described with reference to the drawings. In addition, the same code | symbol is attached | subjected about the element which is the same or it corresponds in each figure, and the overlapping description is abbreviate | omitted.

  In the present embodiment, the vehicle control device according to the present invention is applied to an ACC system mounted on a vehicle. In the ACC system according to the present embodiment, when there is a preceding vehicle ahead of the host vehicle, follow-up control (inter-vehicle distance control) is performed to control the vehicle speed so that the inter-vehicle distance from the preceding vehicle becomes the target inter-vehicle distance. When there is no vehicle, constant speed control is performed to control the vehicle speed so that the vehicle speed of the host vehicle becomes the target vehicle speed. When a preceding vehicle is present, follow-up control is performed until the vehicle speed of the preceding vehicle reaches the target vehicle speed, but when the vehicle speed of the preceding vehicle exceeds the target vehicle speed, constant speed control based on the target vehicle speed is performed.

  Examples of the target vehicle speed include a vehicle speed set by an operation by the driver and a vehicle speed when the driver activates the ACC system. The target vehicle speed is set to a vehicle speed lower than normal for safe driving on a curve or the like. The target inter-vehicle distance includes, for example, an inter-vehicle distance set by an operation by a driver and an inter-vehicle distance set in advance for each vehicle speed. In the follow-up control, the control may be performed not by the inter-vehicle distance but by the inter-vehicle time (= inter-vehicle distance / vehicle speed).

  In this embodiment, there are three forms. In the first embodiment and the second embodiment, the control is switched in response to the driver's brake operation. The third embodiment is a vehicle. This is a mode of control switching corresponding to the curve recognition.

  An ACC system 1 according to the first embodiment will be described with reference to FIG. FIG. 1 is a configuration diagram of an ACC system according to the present embodiment.

  The ACC system 1 prohibits the ACC control when the driver performs a brake operation during the ACC control and determines that there is a high risk for the driver and the driver does not intend to release the ACC control when the ACC control is canceled. If the control is continued by switching to the ACC control at the time of brake operation different from the normal ACC control, and it is determined that the risk is low for the driver or the driver has a strong intention to release the ACC even if the ACC control is canceled. Cancels ACC control. In the ACC system 1, as the ACC control at the time of the brake operation, a large braking force among the control braking force by the ACC control and the requested braking force by the driver's brake operation is applied to the host vehicle to decelerate.

  The ACC system 1 includes a millimeter wave radar 10, a camera 11, a vehicle speed sensor 12, a brake pedal sensor 13, a GPS [Global Positioning System] receiver 14, a map database 15, a brake ECU [Electronic Control Unit] 20, an engine ECU 21, an HMI [ HumanMachine Interface] device 22 and ACCUCU 31 are provided. In the present embodiment, the brake pedal sensor 13 corresponds to the brake operation detecting means described in the claims.

  The millimeter wave radar 10 is a radar for detecting an object ahead of the host vehicle using millimeter waves. The millimeter wave radar 10 is attached to the front center of the host vehicle. The millimeter wave radar 10 transmits the millimeter wave forward while scanning the millimeter wave in the left-right direction, and receives the reflected millimeter wave. The millimeter-wave radar 10 transmits the millimeter-wave transmission / reception information (the horizontal scan angle, transmission time, reception time, reception intensity, etc. of each reflection point (detection point) received) to the ACC ECU 31 as a radar signal. To do. The millimeter wave radar 10 can detect a longer distance than the camera 11.

  The camera 11 is a camera for acquiring an image ahead of the host vehicle. The camera 11 is attached in front of the host vehicle. The camera 11 captures the front of the host vehicle and acquires the captured image. The camera 11 transmits the captured image data to the ACC ECU 31 as an image signal. The detection by the camera 11 is a detection at a short distance compared to the millimeter wave radar 10, but detailed information such as the shape of the object can be acquired.

  The vehicle speed sensor 12 is a wheel speed sensor that detects the rotational speed of the wheel. The vehicle speed sensor 12 transmits the rotation speed to the ACC ECU 31 as a vehicle speed signal. The ACC ECU 31 calculates the vehicle speed from the rotational speed of the wheels. The vehicle speed sensor may be a vehicle speed sensor other than the wheel speed sensor.

  The brake pedal sensor 13 is a sensor that detects the amount of depression of a brake pedal (not shown). The brake pedal sensor 13 detects the depression amount of the brake pedal, and transmits the detected depression amount to the ACC ECU 31 as a brake pedal signal.

  The GPS receiver 14 includes a GPS antenna, a processing device, and the like, and detects the current position of the host vehicle. The GPS receiver 14 receives GPS signals from GPS satellites with a GPS antenna. Then, in the GPS receiver 14, the GPS signal is demodulated by the processing device, and the current position (latitude, longitude) of the host vehicle is calculated based on the demodulated information from each GPS satellite. Then, the GPS receiver 14 transmits the current position of the host vehicle to the ACC ECU 31 as a current position signal. When the navigation system is mounted on the own vehicle, the GPS receiver of the navigation system is shared or the current position is acquired from the navigation system.

  The map database 15 is a database that stores various types of information related to maps. The stored information includes road shape information, road width, road gradient, intersection information, road type information (highway, national road, prefectural road, municipal road, etc.). In particular, the road shape information includes curve information, and the curve information includes information such as a curve radius (curvature radius), a start position and an end position of the curve.

  The brake ECU 20 is a control device that controls the brakes (and hence the braking force) of each wheel. The brake ECU 20 calculates a required braking force (target braking force) based on a brake operation by the driver. Then, the brake ECU 20 sets a brake hydraulic pressure of a wheel cylinder (not shown) of each wheel necessary for achieving the target braking force, and transmits the brake hydraulic pressure as a target hydraulic pressure signal to a brake actuator (not shown). To do. In particular, when the brake ECU 20 receives a brake control signal from the ACC ECU 31, the brake ECU 20 transmits a target hydraulic pressure signal for achieving the target braking force indicated by the brake control signal to the brake actuator.

  The brake actuator is an actuator that adjusts the brake hydraulic pressure of the wheel cylinder of each wheel. The brake actuator operates according to a target hydraulic pressure signal from the brake ECU 20 and adjusts the brake hydraulic pressure of the wheel cylinder. When the target hydraulic pressure is reached, a target braking force is generated in the host vehicle.

  The engine ECU 21 is a control device that controls the engine (and thus the driving force). The engine ECU 21 calculates a required driving force (target driving force) based on an accelerator operation by the driver. Then, the engine ECU 21 sets a target opening of the throttle valve necessary for achieving the target driving force, and transmits the target opening as a target throttle opening signal to a throttle actuator (not shown). In particular, when the engine ECU 21 receives the engine control signal from the ACC ECU 31, the engine ECU 21 transmits a target throttle opening signal for achieving the target driving force indicated by the engine control signal to the throttle actuator.

  The throttle actuator is an actuator that adjusts the opening of a throttle valve (not shown). The throttle actuator operates according to a target throttle opening signal from the engine ECU 21 and adjusts the opening of the throttle valve. When the target throttle opening is reached, a target driving force is generated in the host vehicle.

  The HMI device 22 is a device used when alerting a driver or providing information, and includes a display, a speaker, and the like. The display is an in-vehicle display that is shared by various systems. When the display receives a display signal from the ACC ECU 31, the display displays an image according to the display signal. The speaker is a vehicle-mounted speaker shared by various systems. When the speaker receives a sound signal from the ACC ECU 31, the speaker outputs sound according to the sound signal.

  The ACC ECU 31 is an electronic control unit including a CPU [Central Processing Unit], various memories, and the like, and performs overall control of the ACC system 1. The ACC ECU 31 receives signals from the millimeter wave radar 10, the camera 11, the vehicle speed sensor 12, the brake pedal sensor 13, and the GPS receiver 14, and reads map data around the current position from the map database 15. The ACC ECU 31 uses the received signals and map data for the preceding vehicle recognition process, the normal ACC control process, the curve recognition process, the control switching process, the risk determination process, the ACC release intention determination process, the brake operation ACC control process, and the like. And a control signal is transmitted to the brake ECU 20 or the engine ECU 21 or the HMI device 22 as necessary. In the first embodiment, the control switching process in the ACC ECU 31 corresponds to the control switching means described in the claims.

  The acceleration / deceleration used below is a plus value / minus value, the plus value is acceleration, and the minus value is deceleration. The driving force is a positive value, and the braking force is a negative value. Since acceleration and driving force are expressed as positive values, the larger the value, the larger the acceleration and driving force acting on the vehicle. Since the deceleration and the braking force are expressed by negative values, the smaller the value (the larger the absolute value), the greater the deceleration and braking force that act on the vehicle.

  The preceding vehicle recognition process will be described. The ACC ECU 31 determines the presence / absence of a vehicle (preceding vehicle) traveling in front of the host vehicle based on millimeter wave transmission / reception information from the millimeter wave radar 10 and image information from the camera 11 at regular intervals. At this time, the traveling direction of the host vehicle may be estimated from the steering angle, the yaw rate, etc., and the presence / absence of a preceding vehicle may be determined in consideration of the traveling direction of the host vehicle. When a preceding vehicle exists, the ACC ECU 31 calculates a relative distance, a relative speed, a relative direction, and the like between the host vehicle and the preceding vehicle based on millimeter wave transmission / reception information and image information. Conventional methods are applied to this vehicle detection method and each information calculation method.

  The normal ACC control process will be described. If it is determined in the preceding vehicle recognition process that there is a preceding vehicle, the ACC ECU 31 determines whether the preceding vehicle is based on the difference between the inter-vehicle distance from the preceding vehicle calculated in the preceding vehicle recognition process and the target inter-vehicle distance at regular intervals. The target acceleration / deceleration necessary for the inter-vehicle distance to become the target inter-vehicle distance is calculated. When the target acceleration / deceleration is a positive value, the ACC ECU 31 calculates a control driving force (positive value) from the target acceleration, and transmits the control driving force (target driving force) to the engine ECU 21 as an engine control signal. When the target acceleration / deceleration is a negative value, the ACC ECU 31 calculates a control braking force (negative value) from the target deceleration, and transmits the control braking force (target braking force) to the brake ECU 20 as a brake control signal.

  If it is determined in the preceding vehicle recognition process that there is no preceding vehicle, the ACC ECU 31 adjusts the target speed necessary for the host vehicle speed to become the target vehicle speed based on the difference between the host vehicle speed and the target vehicle speed at regular intervals. Calculate the speed. When the target acceleration / deceleration is a positive value, the ACC ECU 31 calculates a control driving force (positive value) from the target acceleration, and transmits the control driving force (target driving force) to the engine ECU 21 as an engine control signal. When the target acceleration / deceleration is a negative value, the ACC ECU 31 calculates a control braking force from the target deceleration, and transmits the control braking force (target braking force) to the brake ECU 20 as a brake control signal.

  The curve recognition process will be described. The ACC ECU 31 extracts road shape information and curve information around the current position from the map database 15 based on the current position from the GPS receiver 14 at regular intervals, and the current position is a curve (start position, in-curve, end position). ) To determine the curve radius and curvature radius. In addition, the ACC ECU 31 performs road shape recognition based on millimeter wave transmission / reception information from the millimeter wave radar 10 and image information from the camera 11 at regular intervals, determines whether or not the current position is a curve, Calculate radius and radius of curvature. As this road shape recognition method, a conventional method is applied. Then, the ACC ECU 31 comprehensively determines the curve recognition results by these two methods to determine whether or not the current position is a curve, and acquires the curve radius and the curvature radius. In particular, when it is determined as a curve, the ACC ECU 31 sets a target speed lower than the normal target speed in accordance with the curve radius and the like. The road shape recognition using the millimeter wave radar 10 or the camera 11 can more accurately detect the start position of the curve, and the accurate curve radius can be obtained by using the current position by GPS and the data in the map database 15. Can be obtained.

  The control switching process will be described. The ACC ECU 31 determines whether or not the driver is performing a brake operation at regular intervals based on the amount of depression of the brake pedal from the brake pedal sensor 13. When the brake operation is not performed, the ACC ECU 31 continues the normal ACC control process.

  When the brake operation is performed, the ACC ECU 31 performs a risk determination process, and determines whether the risk is high for the driver when the ACC is released. When it is determined that the risk is high when the ACC is released, the ACC ECU 31 performs an ACC release intention determination process to determine whether or not the driver has an intention to release the ACC. If the risk is low even if the ACC is canceled or if the driver is willing to cancel the ACC, the ACC ECU 31 turns off the ACC control. Then, the ACC ECU 31 calculates the control braking force by a process similar to the normal ACC control process at regular intervals, and calculates the driver's required braking force based on the depression amount of the brake pedal from the brake pedal sensor 13. To do. Further, the ACC ECU 31 calculates a target braking force that gradually changes from the control braking force by the ACC control to the driver's required braking force, and transmits the target braking force to the brake ECU 20 as a brake control signal. On the other hand, when the ACC is released and the risk is high and the driver does not intend to release the ACC, the ACC ECU 31 prohibits the ACC control from being turned OFF and performs the ACC control process at the time of brake operation.

  The risk determination process will be described. This risk determination index is determined by whether or not there is a need for rapid deceleration. Specifically, the ACC ECU 31 determines whether or not the curve radius at the current position acquired in the curve recognition process is smaller than the specified curve radius. The specified curve radius is a threshold value for determining a steep curve that requires rapid deceleration, and is set based on an actual vehicle experiment or the like. Incidentally, the curve radius is infinite for straight roads. Further, the ACC ECU 31 determines whether or not the inter-vehicle distance calculated with the preceding vehicle recognition process is shorter than the specified distance. The specified distance is a threshold value for determining a short inter-vehicle distance that requires rapid deceleration, and is set based on an actual vehicle experiment or the like. By the way, when there is no preceding vehicle, the inter-vehicle distance is infinite. When the curve radius is smaller than the specified curve radius or when the inter-vehicle distance from the preceding vehicle is shorter than the specified distance, the ACC ECU 31 determines that the risk is high for the driver (deceleration by ACC is required) when the ACC is released. In this case, if the driver performs a light braking operation, the risk increases when the deceleration braking force by the ACC control is lost. Therefore, it is necessary to continue the deceleration braking force by the ACC control. On the other hand, when the curve radius is equal to or greater than the specified curve radius and the inter-vehicle distance from the preceding vehicle is equal to or greater than the specified distance, the ACC ECU 31 determines that the risk is low for the driver even if the ACC is canceled (deceleration by ACC is unnecessary).

  The ACC release will determination process will be described. As an index for determining whether the driver wants to release ACC, the determination is made by the pedaling force in the brake operation of the driver. The ACC ECU 31 measures the operation time during which the brake operation is continued from the time-series data of the brake pedal depression amount from the brake pedal sensor 13, and determines whether or not the brake operation time is longer than the specified time. The specified distance is a threshold value for determining whether the driver has depressed the brake pedal for a long time to release ACC, and is set based on an actual vehicle experiment or the like. Further, the ACC ECU 31 determines whether or not the amount of depression of the brake pedal from the brake pedal sensor 13 is greater than a specified amount. The specified amount is a threshold value for determining whether the driver has depressed the brake pedal greatly in order to release the ACC, and is set based on an actual vehicle experiment or the like. When the brake operation time is longer than the specified time or when the amount of depression of the brake pedal is greater than the specified amount, the ACC ECU 31 has a willingness to release the ACC (the driver is operating the brake to release the ACC). Is determined. In this case, the driver is performing a strong brake operation and has a strong intention to decelerate by the brake operation by the driver. On the other hand, if the brake operation time is less than the specified time and the amount of depression of the brake pedal is less than the specified amount, the ACC ECU 31 has no intention to release the ACC (the driver performs a slight brake operation to slow down slightly) Determined). In this case, since there is a deceleration braking force by ACC control, the driver performs a light braking operation and also requires a deceleration braking force by ACC control.

  The ACC control process at the time of brake operation will be described. If it is determined that there is a high risk of releasing ACC in the control switching process and that the driver does not intend to release ACC, the ACC ECU 31 performs control braking force (minus) at the same time as the normal ACC control process at regular intervals. Value), and the driver's required braking force (minus value) is calculated based on the depression amount of the brake pedal from the brake pedal sensor 13. Then, the ACC ECU 31 compares the control braking force by the ACC control with the requested braking force by the driver, selects the smaller braking force, and transmits the selected braking force (target braking force) to the brake ECU 20 as a brake control signal. To do. Since the braking force is a negative value, the smaller braking force selected acts on the vehicle as a large braking force. In the brake operation ACC control process, if necessary, the control driving force is set and acceleration control is performed as in the normal ACC control.

  Further, in the ACC ECU 31, in order to present the driver with the reason why the ACC control is continued even though the driver performs the brake operation, the reason (for example, the risk is high for the driver when the ACC is canceled, the driver also An image for displaying (a strong brake operation is not performed to release ACC) is generated, and a display signal including the image information is transmitted to the HMI device 22 (particularly a display). In the conventional ACC system, since the ACC control is released when the driver performs a brake operation, such a display is particularly useful for a driver who is on a vehicle equipped with such an ACC system. It becomes.

  The operation in the ACC system 1 will be described with reference to FIG. In particular, the control switching process, the risk determination process, and the ACC release will determination process in the ACC ECU 31 will be described with reference to the flowcharts of FIGS. 2, 3, and 4. FIG. 2 is a flowchart showing a flow of control switching processing corresponding to a brake operation in the ACC ECU according to the first embodiment. FIG. 3 is a flowchart showing the flow of the risk determination process in the flowcharts of FIGS. 2 and 5. FIG. 4 is a flowchart showing the flow of the ACC release will determination process in the flowcharts of FIGS. 2 and 5.

  The millimeter wave radar 10 transmits and receives millimeter waves while scanning in the left-right direction at regular intervals, and transmits the transmitted and received information to the ACC ECU 31 as radar signals. The camera 11 captures the front of the host vehicle at regular time intervals and transmits the captured image to the ACC ECU 31 as an image signal. The vehicle speed sensor 12 detects the rotational speed of the wheel at regular intervals, and transmits the rotational speed to the ACC ECU 31 as a vehicle speed signal. The brake pedal sensor 13 detects the amount of depression of the brake pedal at regular intervals, and transmits the detected amount of depression to the ACCU ECU 31 as a brake pedal signal. The GPS receiver 14 demodulates the GPS signal every time a GPS antenna receives a GPS signal from a GPS satellite, and calculates the current position of the vehicle based on the demodulated information from each GPS satellite. The current position or the like is transmitted to the ACC ECU 31 as a current position signal. The ACC ECU 31 receives various signals from the sensors 10, 11, 12, 13 and the GPS receiver 14.

  The ACC ECU 30 determines the presence or absence of the preceding vehicle based on the radar signal or the image signal, and calculates the inter-vehicle distance from the preceding vehicle when the preceding vehicle exists. Further, the ACC ECU 31 calculates the vehicle speed of the host vehicle based on the vehicle speed signal.

  When there is a preceding vehicle, the ACC ECU 31 sets the target acceleration / deceleration necessary for the inter-vehicle distance from the preceding vehicle to be the target inter-vehicle distance at regular intervals by the normal vehicle accelerating vehicle follow-up control. When the target acceleration / deceleration is a positive value, the ACC ECU 31 calculates a control driving force from the target acceleration, and transmits the control driving force (target driving force) to the engine ECU 21 as an engine control signal. When this engine control signal is received, the engine ECU 21 transmits a target throttle opening signal for achieving the target driving force to the throttle actuator. When this target throttle opening signal is received, the throttle actuator operates according to the target throttle opening, and adjusts the opening of the throttle valve. When the target throttle opening is reached, a target driving force is generated in the host vehicle, the target acceleration is reached, and the target vehicle speed is reached. When the target acceleration / deceleration is a negative value, the ACC ECU 31 calculates a control braking force from the target deceleration, and transmits a brake control signal indicating the control braking force (target braking force) to the brake ECU 20. When the brake control signal is received, the brake ECU 20 transmits a target hydraulic pressure signal for achieving the target braking force to the brake actuator. When the target hydraulic pressure signal is received, the brake actuator operates according to the target hydraulic pressure, and adjusts the brake hydraulic pressure of the wheel cylinder. When the target hydraulic pressure is reached, a target braking force is generated in the host vehicle, the target deceleration is reached, and the target vehicle speed is reached. Thus, the host vehicle is adjusted so that the inter-vehicle distance from the preceding vehicle becomes the target inter-vehicle distance.

  When there is no preceding vehicle, the ACC ECU 31 sets the target acceleration / deceleration necessary for the host vehicle speed to become the target vehicle speed at regular intervals by the constant speed control of the normal ACC control. Based on this target acceleration / deceleration, the ACC ECU 31, the engine ECU 21 (throttle actuator, throttle valve), and the brake ECU 20 (brake actuator, wheel cylinder) perform the same operation as the preceding vehicle following control described above. As a result, the vehicle speed is adjusted so that the vehicle speed becomes the target vehicle speed.

  The ACC ECU 31 extracts road shape information and curve information around the current position from the map database 15 based on the current position of the GPS signal at regular intervals, determines whether or not the current position is a curve, and determines the curve radius and curvature radius. To get. In addition, the ACC ECU 31 recognizes the road shape at regular intervals based on the radar signal and the image signal, determines whether or not the current position is a curve, and calculates a curve radius and a curvature radius. Then, the ACC ECU 31 comprehensively determines the curve recognition results by these two methods to determine whether the curve is a curve, and acquires the curve radius and the curvature radius. If the curve is determined, the ACC ECU 31 sets a target speed lower than normal according to the curve radius or the like.

  The ACC ECU 31 determines whether or not the driver has performed a brake operation based on the brake pedal signal (S10). If it is determined in S10 that the driver does not perform the brake operation, the ACC ECU 31 continues the normal ACC control (S11).

  If it is determined in S10 that the driver is performing a brake operation, the ACC ECU 31 proceeds to a risk determination process, and determines whether or not the risk is high when ACC is released (S12). When the process proceeds to the risk determination process, the ACC ECU 31 determines whether or not the curve radius is smaller than the specified curve radius (S20). If it is determined in S20 that the curve radius is equal to or greater than the specified curve radius, the ACC ECU 31 determines whether the inter-vehicle distance from the preceding vehicle is shorter than the specified distance (S21). If it is determined in S21 that the inter-vehicle distance from the preceding vehicle is equal to or greater than the specified distance, the ACC ECU 31 determines that the risk is low even if the ACC is canceled (S22). On the other hand, if it is determined in S20 that the curve radius is smaller than the specified curve radius, or if it is determined in S21 that the inter-vehicle distance from the preceding vehicle is shorter than the specified distance, the ACC ECU 31 determines that the risk is high if the ACC is canceled. (S23).

  If it is determined that the risk is high when the ACC is canceled in S12, the ACC ECU 31 proceeds to an ACC cancellation intention determination process and determines whether or not the driver has an ACC cancellation intention (S13). When the process proceeds to the ACC release intention determination process, the ACC ECU 31 determines whether or not the brake operation time by the driver is longer than the specified time based on the brake pedal signal (S30). When it is determined in S30 that the brake operation time is equal to or shorter than the specified time, the ACC ECU 31 determines whether the brake depression amount by the driver is larger than the specified amount based on the brake pedal signal (S31). If it is determined in S31 that the brake depression amount is equal to or less than the specified amount, the ACC ECU 31 determines that the driver does not have an intention to release the ACC (S32). On the other hand, if it is determined in S30 that the brake operation time is longer than the specified time, or if it is determined in S31 that the brake depression amount is larger than the specified amount, the ACC ECU 31 determines that the driver has an intention to release the ACC (S33). .

  If it is determined in S13 that the driver does not intend to release the ACC, the ACC ECU 31 calculates a control braking force (minus value) in the same manner as in the normal ACC control process described above, and requests the driver's required braking force (based on the brake pedal signal). (Minus value) is calculated, the smaller one of the control braking force of the ACC and the driver's required braking force is selected, and the selected braking force (target braking force) is transmitted to the brake ECU 20 as a brake control signal. (S14). When this brake control signal is received, the brake ECU 20 performs the same operation as described above. As a result, the own vehicle generates a braking force, which is the greater of the ACC control and the driver request, and decelerates. Further, the ACC ECU 31 generates an image for displaying the reason for continuing the ACC, and transmits a display signal including the image information to the HMI device 22 (display) (S15). When this display signal is received, the reason for continuing the ACC is displayed on the display.

  If it is determined that the risk is low even if ACC is canceled in S12, or if it is determined in S13 that the driver has an intention to cancel ACC, the ACC ECU 31 turns off the ACC control (S16). Then, the ACC ECU 31 calculates the control braking force in the same manner as in the normal ACC control process described above, calculates the driver's required braking force based on the brake pedal signal, and gradually increases the ACC control braking force from the driver's required braking force. The target braking force to be changed is calculated, and the target braking force is transmitted to the brake ECU 20 as a brake control signal (S17). When this brake control signal is received, the brake ECU 20 performs the same operation as described above. As a result, in both vehicles, a braking force that gradually changes from the braking force by the ACC control to the braking force according to the driver's braking operation is generated and decelerated.

  According to the ACC system 1, even when the driver performs a brake operation during the ACC operation, the ACC control is not turned off when it is determined that the risk is high when the ACC is released and the driver does not intend to release the ACC. By continuing the control, the deceleration braking force by the ACC control can be continuously applied to the host vehicle, and the driver does not feel uncomfortable due to the deceleration braking force being lost by the ACC control. By continuing this ACC control, even if there is a preceding vehicle in a driving scene where the driver needs to depress the brake pedal lightly, even if there is a preceding vehicle, a safe inter-vehicle distance can be secured, and the speed will be reduced to a safer speed by using a curve or the like. Can be made. Furthermore, since the operation time of ACC is extended, safety and fuel consumption are also improved.

  According to the ACC system 1, it is possible to determine the risk when the ACC is canceled with high accuracy by determining the necessity of rapid deceleration based on the curve radius and the inter-vehicle distance from the preceding vehicle. Further, according to the ACC system 1, by determining the degree of brake operation by the driver based on the brake operation time and the brake depression amount, it is highly accurate whether the driver wants to release ACC and decelerate by his / her own brake operation. Can be determined.

  According to the ACC system 1, when the driver performs the brake operation during the ACC operation, when the ACC control is continuously performed, the driver is misunderstood that the system malfunctions by presenting the reason to the driver. You can avoid automation surprises.

  According to the ACC system 1, when the ACC control is continuously performed, by generating a large braking force of the ACC control braking force and the driver requested braking force in the vehicle, the vehicle can be decelerated with a larger braking force. A safe inter-vehicle distance from the preceding vehicle can be secured, or the speed can be lowered to a safe speed by a curve or the like.

  With reference to FIG. 1, an ACC system 2 according to a second embodiment will be described. Compared with the ACC system 1 according to the first embodiment, the ACC system 2 is a normal operation performed when it is determined that the driver has a higher risk for releasing the ACC and the driver does not intend to release the ACC. Only ACC control at the time of brake operation different from ACC control is different. In the ACC system 2, ACC control limited to deceleration is performed as ACC control during brake operation.

  The ACC system 2 includes a millimeter wave radar 10, a camera 11, a vehicle speed sensor 12, a brake pedal sensor 13, a GPS receiver 14, a map database 15, a brake ECU 20, an engine ECU 21, an HMI device 22, and an ACC ECU 32. Since the ACC system 2 differs from the ACC system 1 only in the processing of the ACC ECU 32, only the ACC ECU 32 will be described.

  The ACC ECU 32 is an electronic control unit including a CPU, various memories, and the like, and performs overall control of the ACC system 2. The ACC ECU 32 receives signals from the millimeter wave radar 10, the camera 11, the vehicle speed sensor 12, the brake pedal sensor 13, and the GPS receiver 14, and reads map data around the current position from the map database 15. Then, the ACC ECU 32 uses the received signals and map data to perform preceding vehicle recognition processing, normal ACC control processing, curve recognition processing, control switching processing, risk determination processing, ACC release will determination processing, and brake operation ACC control processing. The control signal is transmitted to the brake ECU 20 or the engine ECU 21 or the HMI device 22 as necessary. The ACC ECU 32 performs a process different from the ACC ECU 31 according to the first embodiment only in the brake operation ACC control process among these processes. Therefore, only the ACC control process during brake operation will be described. In the second embodiment, the control switching process in the ACC ECU 32 corresponds to the control switching means described in the claims.

  The brake operation ACC control process (deceleration limited ACC control process) will be described. When it is determined in the preceding vehicle recognition process that the preceding vehicle exists, the ACC ECU 32 sets the inter-vehicle distance to the preceding vehicle to the target inter-vehicle distance based on the difference between the inter-vehicle distance from the preceding vehicle and the target inter-vehicle distance at regular intervals. The target deceleration (minus value) necessary to be calculated is calculated, the control braking force (minus value) is calculated from the target deceleration, and the control braking force (target braking force) is transmitted to the brake ECU 20 as a brake control signal. To do. If it is determined in the preceding vehicle recognition process that the preceding vehicle does not exist, the ACC ECU 32 reduces the target reduction necessary for the host vehicle speed to become the target vehicle speed based on the difference between the host vehicle speed and the target vehicle speed at regular intervals. The speed (minus value) is calculated, the control braking force (minus value) is calculated from the target deceleration, and the control braking force (target braking force) is transmitted to the brake ECU 20 as a brake control signal. In particular, the ACC ECU 32 calculates a control braking force that can cause the vehicle to generate a braking force equal to or greater than the braking force equivalent to the engine brake when the driver does not perform the accelerator operation. In this brake operation ACC control process, acceleration control is not performed by setting a control driving force that is normally performed in ACC control.

  Furthermore, in the ACC ECU 32, in order to present to the driver the reason for continuing the ACC control despite the driver performing the brake operation and the transition to the ACC control limited to the deceleration, the reason for the ACC continuation and the deceleration An image for displaying a transition to limited ACC control (for example, performing ACC control without acceleration) is generated, and a display signal including the image information is transmitted to the HMI device 22 (particularly, a display).

  The operation in the ACC system 2 will be described with reference to FIG. In particular, the control switching process, the risk determination process, and the ACC release will determination process in the ACC ECU 32 will be described along the flowcharts of FIGS. 5, 3, and 4. FIG. 5 is a flowchart showing a flow of control switching processing corresponding to the brake operation in the ACC ECU according to the second embodiment. The millimeter wave radar 10, the camera 11, the vehicle speed sensor 12, the brake pedal sensor 13, the GPS receiver 14, the brake ECU 20, the engine ECU 21, and the HMI device 22 perform the same operations as in the first embodiment. Description is omitted.

  In the ACC ECU 32, the processes in S40 to S43 are the same as the processes in S10 to S13 of the ACC ECU 31 according to the first embodiment.

  If it is determined that the risk is high when the ACC is canceled in S42 and it is determined in S43 that the driver does not intend to cancel the ACC, the ACC ECU 32 determines that the preceding vehicle is present when the preceding vehicle exists by the ACC control limited to the deceleration. The control braking force (minus value) for maintaining a safe distance between vehicles is calculated, and when there is no preceding vehicle, the control braking force (minus value) for decelerating to a safe speed is calculated. The power (target braking force) is transmitted as a brake control signal to the brake ECU 20 (S44). When this brake control signal is received, the brake ECU 20 performs the same operation as in the first embodiment. As a result, the own vehicle generates a braking force by ACC control and decelerates. Further, the ACC ECU 32 generates an image for displaying the reason for ACC continuation and the transition to the deceleration limited ACC control, and transmits a display signal including the image information to the HMI device 22 (display) (S45). When this display signal is received, the display displays the ACC continuation reason and the transition to deceleration limited ACC control.

  When it is determined that the risk is low when ACC is canceled in S42, or when it is determined in S43 that the driver has an intention to cancel ACC, the ACC ECU 32 relates to each process of S46 and S47 according to the first embodiment. The same processing as S16 and S17 of the ACC ECU 31 is performed.

  The ACC system 2 has the same effects as the ACC system 1 according to the first embodiment, and also has the following effects. According to the ACC system 2, when the ACC control is continuously performed, the ACC control limited to the deceleration is performed, so that the driver does not accelerate in the driving scene where the brake operation is performed, and the vehicle is surely connected with the preceding vehicle. It is possible to secure a safe inter-vehicle distance or to reduce the speed to a safe speed by a curve or the like.

  With reference to FIG. 1, an ACC system 3 according to a third embodiment will be described. The ACC system 3 performs curve recognition using a GPS current position and a map database and curve recognition using a millimeter wave radar and a camera, and switches ACC control according to two curve recognition results.

  The ACC system 3 includes a millimeter wave radar 10, a camera 11, a vehicle speed sensor 12, a brake pedal sensor 13, a GPS receiver 14, a map database 15, a brake ECU 20, an engine ECU 21, an HMI device 22, and an ACC ECU 33. Since the ACC system 3 differs from the ACC system 1 only in the processing of the ACC ECU 33, only the ACC ECU 33 will be described.

  The ACC ECU 33 is an electronic control unit including a CPU, various memories, and the like, and comprehensively controls the ACC system 3. The ACC ECU 33 receives signals from the millimeter wave radar 10, the camera 11, the vehicle speed sensor 12, the brake pedal sensor 13, and the GPS receiver 14, and reads map data around the current position from the map database 15. The ACC ECU 33 performs a preceding vehicle recognition process, a curve recognition process, a control switching process, a curve deceleration control process, an engine brake deceleration control process, and a normal ACC control process using each received signal and map data. A control signal is transmitted to the brake ECU 20 or the engine ECU 21 or the HMI device 22. The ACC ECU 33 performs the same process as the ACC ECU 31 according to the first embodiment for the preceding vehicle recognition process, the curve recognition process, and the normal ACC control process among these processes. Therefore, only control switching processing, curve deceleration control processing, and engine brake deceleration control processing will be described.

  The control switching process will be described. The ACC ECU 33 determines whether or not a curve has been recognized by curve recognition based on the current position in the GPS receiver 14 and road shape information and curve information around the current position in the map database 15. Further, the ACC ECU 33 determines whether or not the curve can be recognized by the curve recognition based on the millimeter wave transmission / reception information of the millimeter wave radar 10 and the image information of the camera 11. When the curve can be recognized by both curve recognitions (when the curves can be recognized by interpolating the accuracy of the two curve recognitions), the curve is highly reliable. Allow deceleration control and perform curve deceleration processing. When the curve can be recognized only by either one of the curve recognitions (when the curve can be recognized only with the accuracy of the one curve recognition), since the reliability of the curve is low, the ACC ECU 33 corresponds to the engine brake for the curve. The engine brake deceleration control process is performed. When the curve cannot be recognized by both curve recognitions (when the accuracy cannot be recognized by interpolating the accuracy of the two curve recognitions), the ACC ECU 33 performs normal ACC control because the reliability is not a curve. Permit and perform normal ACC control processing.

  The curve deceleration control process will be described. When the ACC ECU 33 determines that the preceding vehicle exists in the preceding vehicle recognition process, the ACC ECU 33 determines the inter-vehicle distance from the preceding vehicle based on the difference between the inter-vehicle distance from the preceding vehicle and the target inter-vehicle distance at regular intervals. Calculate the target deceleration (negative value) required to reach the inter-vehicle distance, calculate the control braking force (negative value) from the target deceleration, and use the control braking force (target braking force) as a brake control signal for braking. It transmits to ECU20. If it is determined in the preceding vehicle recognition process that there is no preceding vehicle, the ACC ECU 33 reduces the target required for the host vehicle speed to become the target vehicle speed based on the difference between the host vehicle speed and the target vehicle speed at regular intervals. The speed (minus value) is calculated, the control braking force (minus value) is calculated from the target deceleration, and the control braking force (target braking force) is transmitted to the brake ECU 20 as a brake control signal. Further, the ACC ECU 33 generates an image for displaying the curve deceleration control in order to present to the driver that normal deceleration control for the curve is to be performed, and displays a display signal including the image information as the HMI device 22 (particularly, Display).

  The engine brake deceleration control process will be described. The ACC ECU 33 calculates a control braking force (minus value) that can generate a braking force equivalent to the engine brake, and transmits the control braking force (target braking force) to the brake ECU 20 as a brake control signal. Further, since the ACC ECU 33 performs only deceleration control equivalent to engine braking in a curve, an image or sound for alerting the curve deceleration is generated, and a display signal including the image information or a sound signal including the sound information is generated. Transmit to the HMI device 22 (display, speaker).

  The operation in the ACC system 3 will be described with reference to FIG. In particular, the control switching process in the ACC ECU 33 will be described with reference to the flowchart of FIG. FIG. 6 is a flowchart showing a flow of control switching processing corresponding to curve recognition in the ACC ECU according to the third embodiment. The millimeter wave radar 10, the camera 11, the vehicle speed sensor 12, the brake pedal sensor 13, the GPS receiver 14, the brake ECU 20, the engine ECU 21, and the HMI device 22 perform the same operations as in the first embodiment. Description is omitted.

  The ACC ECU 33 performs the curve recognition process described in the first embodiment. Then, the ACC ECU 33 determines whether or not the curve is recognized by the curve recognition process using the current position in the GPS receiver 14 and the data in the map database 15 at regular time intervals (S50). When it is determined that the curve is recognized in S50, the ACC ECU 33 determines whether or not the curve is recognized by the curve recognition process using the radar information of the millimeter wave radar 10 and the image information of the camera 11 ( S51). If it is determined in S50 that the curve is not recognized, the ACC ECU 33 determines whether or not the curve is recognized by the curve recognition process using the radar information of the millimeter wave radar 10 and the image information of the camera 11. (S52).

  If it is determined in S51 that the curve is recognized, the ACC ECU 33 calculates a control braking force for maintaining a safe distance between the preceding vehicle and the preceding vehicle when there is a preceding vehicle by the deceleration control for the normal curve. When there is no preceding vehicle, a control braking force for decelerating to a safe speed is calculated, and the control braking force (target braking force) is transmitted to the brake ECU 20 as a brake control signal (S53). When this brake control signal is received, the brake ECU 20 performs the same operation as in the first embodiment. As a result, the own vehicle decelerates by generating a braking force according to the curve. Further, the ACC ECU 33 generates an image for displaying the transition to the curve control deceleration, and transmits a display signal including the image information to the HMI device 22 (display) (S54). When this display signal is received, the display displays a transition to curve control deceleration.

  If it is determined that the curve is not recognized in S51 or if it is determined that the curve is recognized in S52, the ACC ECU 33 calculates a control braking force equivalent to the engine brake, and the control braking force (target braking force). ) As a brake control signal is transmitted to the brake ECU 20 (S55). When this brake control signal is received, the brake ECU 20 performs the same operation as in the first embodiment. As a result, the own vehicle generates a weak braking force equivalent to the engine brake and slowly decelerates. Further, the ACC ECU 33 generates an image and sound for calling attention to curve deceleration, and transmits a display signal composed of the image information and a sound signal composed of the sound information to the HMI device 22 (display, speaker) (S56). . When this display signal is received, the display displays a warning for the curve. Further, when this audio signal is received, the speaker outputs a warning for the curve.

  If it is determined in S52 that the curve is not recognized, the ACC ECU 33 performs normal ACC control (S57). For this normal ACC control, the same processing as described in the first embodiment is performed.

  According to this ACC system 3, curve recognition is performed by two methods using different sensors, and deceleration control is performed according to the reliability of curve recognition by switching the control according to the two curve recognition results. Can do. Further, according to the ACC system 3, the curve recognition accuracy can be improved by performing curve recognition by two methods using different sensors. By the way, there is a position error in the current position by GPS, and it is expensive by RTK-GPS or the like in order to improve the accuracy, and it is expensive in maintenance or the like to improve the accuracy of the electronic map data. However, the accuracy of curve recognition can be improved without such cost increase by using the curve recognition processing by road shape recognition using a radar or a camera necessary for the ACC system.

  As mentioned above, although embodiment which concerns on this invention was described, this invention is implemented in various forms, without being limited to the said embodiment.

  For example, in the present embodiment, the present invention is applied to an ACC system that performs preceding vehicle follow-up control (inter-vehicle distance control) and constant speed control, but can also be applied to a system that performs only one of the controls.

  In this embodiment, a millimeter wave radar or a camera is applied as means for detecting a preceding vehicle. However, other radars such as a laser radar may be used, or an inter-vehicle communication device that acquires information from vehicles around the own vehicle. Alternatively, other detection means may be used.

  In this embodiment, the GPS receiver is provided with a map database, and the curve is recognized from the current GPS position and the curve information based on the map data. However, in the case of a vehicle equipped with a navigation system, such a curve is used. Recognition may be performed by the navigation system.

  In the present embodiment, the engine ECU and the brake ECU are used to perform the engine control and the brake control. However, the actuator may be controlled by the ACC ECU to directly perform the engine control and the brake control.

  Further, in the present embodiment, an example of the risk determination method when the ACC is canceled is shown, but the risk may be determined by another method. In the present embodiment, an example of a determination method of the driver's ACC release intention by the brake operation is shown, but the ACC release intention may be determined by other methods.

  In the present embodiment, curve recognition using GPS current position and map database and road shape recognition using millimeter wave radar and camera are performed, and curve recognition is performed by integrating the two curve recognition results. However, curve recognition may be performed by only one of the methods, or only one sensor or another sensor such as a laser radar may be used for curve recognition by road shape recognition. Curve recognition may be performed by this method.

  Further, in the present embodiment, when the braking force is generated by vehicle control, the brake braking actuator is used to generate the control braking force by the mechanical brake, but the engine braking is also used to generate the control braking force. Good. In the case of a vehicle having a motor as a drive source, a control braking force may be generated using a regenerative brake.

  DESCRIPTION OF SYMBOLS 1, 2, 3 ... ACC system, 10 ... Millimeter wave radar, 11 ... Camera, 12 ... Vehicle speed sensor, 13 ... Brake pedal sensor, 14 ... GPS receiver, 15 ... Map database, 20 ... Brake ECU, 21 ... Engine ECU , 22 ... HMI device, 31, 32, 33 ... ACCUCU.

Claims (1)

A vehicle control device for controlling the vehicle speed of the host vehicle,
Brake operation detecting means for detecting the brake operation of the driver of the own vehicle;
When the driver of the host vehicle performs a braking operation during vehicle speed control, if the pedaling force in the braking operation is below the threshold, the vehicle speed control is prohibited from being released and switched to a vehicle speed control during braking that is different from the normal vehicle speed control. A vehicle control device comprising: control switching means for switching from vehicle speed control during brake operation to normal vehicle speed control when the driver of the host vehicle finishes the brake operation.

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