JP4904924B2 - Vehicle travel control device and vehicle travel control method - Google Patents

Description

  The present invention relates to a vehicle travel control device and a vehicle travel control method, and more particularly to a vehicle travel control device and a vehicle travel control method for stopping a host vehicle.

  In conventional vehicles, as a means to reduce the driving operation of the host vehicle by the driver, constant speed traveling control for controlling the host vehicle to travel at a constant speed at a speed set by the driver, A vehicle traveling control device that performs vehicle traveling control that performs following traveling control so as to follow the vehicle, that is, adaptive cruise control (ACC), is mounted. In ACC, the target acceleration is calculated according to the traveling state of the host vehicle, such as acceleration for maintaining constant speed driving (including deceleration) and acceleration for following a preceding vehicle at a certain distance. The braking / driving force based on the target acceleration is applied to the vehicle by the braking / driving force generating means. The braking / driving force generating means includes an engine (including a transmission) and a brake device mounted on the vehicle.

  For example, when the preceding vehicle stops when the follow-up traveling control is performed in the ACC, the vehicle traveling control device stops the own vehicle in order to maintain a predetermined inter-vehicle distance from the preceding vehicle. Here, the vehicle speed sensor that detects the vehicle speed of the host vehicle cannot detect an extremely low vehicle speed (for example, a vehicle speed of 1 km / h or less). In other words, when the host vehicle is at an extremely low vehicle speed, the vehicle travel control device stops the host vehicle even if the host vehicle does not actually stop because the vehicle speed sensor does not detect the vehicle speed of the host vehicle. It will be judged that you are doing.

  Therefore, when the host vehicle is at an extremely low vehicle speed, the vehicle travel control device mainly applies a stop holding braking force by the brake device in order to stop the host vehicle and hold the stopped state. As a vehicle travel control device that applies a stop holding braking force, there is a conventional one as shown in Patent Document 1, for example. In the vehicle travel control device (inter-vehicle distance control device) disclosed in Patent Literature 1, when the target speed becomes a predetermined value or less, the target braking / driving force is switched from the target braking / driving force to the stop holding braking force (target braking force) to stop the host vehicle. Force switching means is provided.

JP 2000-25487 A

  However, even in the vehicle travel control apparatus as shown in Patent Document 1, if the vehicle speed of the host vehicle is not detected by the vehicle speed sensor, that is, the actual vehicle speed of the host vehicle cannot be detected by the vehicle speed sensor. For example, the target braking / driving force is switched to the stop holding braking force (target braking force). Accordingly, a target braking / driving force for stopping the host vehicle is applied to the host vehicle, and even if the host vehicle is slowly decelerating toward the stop, if the host vehicle has an extremely low vehicle speed, A stop holding braking force that gives a greater deceleration of the host vehicle than the braking / driving force is applied, and the vehicle is greatly decelerated and stopped. As a result, there is a problem that the shock when the host vehicle is stopped is large.

  The present invention has been made in view of the above, and an object of the present invention is to provide a vehicle travel control device and a vehicle travel control method capable of suppressing a shock when the host vehicle is stopped.

In order to solve the above-described problems and achieve the object, in the vehicle travel control device according to the present invention, the deceleration braking force for stopping the host vehicle or the stop holding control for holding the stop state of the host vehicle. A braking force generating means for applying power to the host vehicle, a vehicle speed detecting unit for detecting the vehicle speed of the host vehicle, and a vehicle undetectable state in which the vehicle speed cannot be detected by the vehicle speed detecting unit. A switching means for switching the braking force applied to the host vehicle by the braking force generating means from a deceleration braking force to a stop-hold braking force; and a braking force applied to the host vehicle by the braking force generating means after the non-detectable state. Switching interval for setting the switching interval from the deceleration braking force to the stop holding braking force based on the magnitude of the braking force applied to the host vehicle in the non-detectable state Comprising a constant section, wherein the switching interval setting means, when the magnitude of the braking force applied to the vehicle in the undetectable state is changed to change based on the switching intervals in the change.

  In the present invention, the vehicle travel control device further includes target acceleration calculation means for calculating at least target acceleration of the host vehicle for applying braking force to the host vehicle by the braking force generation unit, The magnitude of the braking force applied to is the magnitude of the calculated target acceleration.

  According to the present invention, in the vehicle travel control device, the braking force generation means applies a braking force to the host vehicle by hydraulic pressure, a brake actuator that applies hydraulic pressure to the brake body, and the braking body. A brake control device for calculating a target hydraulic pressure, wherein the magnitude of the braking force applied to the host vehicle is the calculated target hydraulic pressure.

Further, in the vehicle travel control method according to the present invention, the procedure for determining whether or not the vehicle speed of the host vehicle can no longer be detected, and the host vehicle cannot be detected after the vehicle speed of the host vehicle cannot be detected. A switching interval from the deceleration braking force for stopping the host vehicle to the stop holding braking force for maintaining the stopped state of the host vehicle is applied to the host vehicle in the undetectable state. When the magnitude of the braking force to be changed changes , the procedure for setting based on the change , and the braking force applied to the host vehicle after the switching interval elapses after the undetectable state is maintained from the deceleration braking force to the stop. And switching to a braking force.

  According to these inventions, when the deceleration braking force is applied to the host vehicle, the vehicle speed is detected when the vehicle speed cannot be detected by the vehicle speed detecting means, for example, the wheel speed sensor. Although the braking force is switched from the deceleration braking force to the stop holding braking force by the switching means, the switching interval setting means adjusts the time until the actual vehicle speed of the host vehicle becomes 0 km / h after the switching interval, that is, the detection impossible state. It is set based on the magnitude of the braking force applied to the vehicle, for example, the magnitude of the calculated target acceleration or the magnitude of the calculated target hydraulic pressure. Accordingly, even if the vehicle speed of the host vehicle is no longer detected by the vehicle speed detecting unit, the switching unit is not able to detect the deceleration braking force until the switching interval, that is, the actual vehicle speed of the host vehicle becomes 0 km / h, and the host vehicle stops. There is no switching to the stop-hold braking force. Thereby, since the stop holding braking force is not applied to the own vehicle until the own vehicle is stopped, a shock when the own vehicle is stopped can be suppressed.

  According to the present invention, in the vehicle travel control device, the switching interval setting means changes the switching interval based on the change when the magnitude of the braking force applied to the host vehicle in the undetectable state changes. It is characterized by doing.

  According to the present invention, in the vehicle travel control device, the switching interval setting means increases the switching interval when a braking force applied to the host vehicle in the undetectable state decreases.

  According to these inventions, when the magnitude of the braking force applied to the host vehicle changes after the vehicle speed detecting unit no longer detects the vehicle speed of the host vehicle, the switching interval setting unit changes the switching interval to the change. Change based on. For example, when the braking force applied to the host vehicle decreases after the vehicle speed is not detected by the vehicle speed detecting means, the switching interval is increased. In other words, when it becomes difficult for the host vehicle to decelerate after the vehicle speed is no longer detected by the vehicle speed detecting means, the time is increased until the host vehicle is stopped from the undetectable state, so the switching interval is increased. . Therefore, even if the magnitude of the braking force applied to the host vehicle from the undetectable state changes, the stop holding braking force is not applied to the host vehicle until the host vehicle is stopped. The shock at the time of a stop can further be suppressed.

  According to the present invention, in the vehicle travel control device, the switching interval setting means does not change the switching interval after the braking force applied to the host vehicle is most reduced from the undetectable state. To do.

  According to this invention, the switching interval setting means changes the switching interval based on the change when the magnitude of the braking force applied to the host vehicle changes after the vehicle speed of the host vehicle is no longer detected by the vehicle speed detecting unit. However, the switching interval is not changed after the braking force applied to the host vehicle has been reduced most. That is, even if the braking force applied to the host vehicle increases from the smallest value, the switching interval does not decrease from the switching interval when the braking force applied to the host vehicle decreases most. Therefore, the host vehicle is surely in a stopped state between the detection disabled state and the switching interval. Thereby, since the stop holding braking force is not applied to the host vehicle until the host vehicle is stopped, a shock when the host vehicle is stopped can be further suppressed.

  The vehicle travel control device and the vehicle travel control method according to the present invention suppress the shock when the host vehicle is stopped because the stop holding braking force is not applied to the host vehicle until the host vehicle is stopped. Can do.

  Hereinafter, the present invention will be described in detail with reference to the drawings. In addition, this invention is not limited by the following Example. In addition, constituent elements in the following embodiments include those that can be easily assumed by those skilled in the art or those that are substantially the same. Further, the target acceleration in the following embodiment includes a positive acceleration and a negative acceleration (deceleration). The braking / driving force includes a positive driving force and a negative braking force.

  FIG. 1 is a diagram illustrating a configuration example of a vehicle travel control device according to the present invention. As shown in the figure, the vehicle travel control device 1 is mounted on a vehicle (not shown) (hereinafter simply referred to as “own vehicle”), and can reduce the driving operation of the host vehicle by the driver. The vehicle traveling control that can be performed, that is, ACC is performed. The vehicle travel control device 1 includes a control device 2, a millimeter wave radar 3, a wheel speed sensor 4, a brake device 5, and an engine 6. Note that the vehicle travel control in the embodiment performs only the follow-up travel control that causes the host vehicle to follow the preceding vehicle. However, the present invention is not limited to this, and the host vehicle travels at a set speed. You may perform the constant speed running control etc. to be performed.

  The control device 2 controls the entire vehicle travel control device 1. The control device 2 includes at least a follow-up travel control unit 21, a target acceleration calculation unit 22, a stop / hold control unit 23, and a braking / driving force control unit 24.

  The follow-up running control unit 21 is a follow-up running control unit. The follow-up running control unit 21 provides follow-up running that gives the vehicle a follow-up braking / driving force for following the preceding vehicle by at least one of the brake device 5 serving as a braking force generating unit or the engine 6 serving as a braking / driving force generating unit. Control is performed. That is, the follow-up running control unit 21 can apply a deceleration braking force (included in the follow-up braking / driving force) for stopping the host vehicle to the host vehicle by the brake device 5 serving as a braking force generating unit. But there is.

  This follow-up travel control unit 21 travels in the same lane as the vehicle is traveling in the traveling direction of the preceding vehicle, for example, the host vehicle (not shown), from the position data of the object detected by the millimeter wave radar 3. It recognizes the vehicle that is on. The follow-up travel control unit 21 is connected to the millimeter wave radar 3 and the target acceleration calculation unit 22. Accordingly, the tracking data of the object detected by the millimeter wave radar 3 is input to the follow-up travel control unit 21, the preceding vehicle is recognized from the input position data, and the recognized position data of the preceding vehicle is used as the target acceleration. Output to the calculation unit 22.

  The target acceleration calculation unit 22 is a target acceleration calculation unit. The target acceleration calculation unit 22 calculates the target acceleration S of the host vehicle. The target acceleration calculation unit 22 calculates the target acceleration S according to the vehicle traveling control state of the host vehicle by the vehicle traveling control device 1, in this embodiment, the following traveling control. The target acceleration calculating unit 22 provides a target braking / driving force (including deceleration braking force) to the host vehicle by at least one of the brake device 5 and the engine 6 when the vehicle traveling control device 1 performs the following traveling control. The acceleration S is calculated. The target acceleration calculation unit 22 calculates a plurality of target accelerations for tracking based on the position data of the preceding vehicle from the tracking traveling control unit 21. For example, the target acceleration calculation unit 22 indicates that the brake acceleration follow-up target acceleration calculated on the assumption that the brake device 5 may be operated (brake permission) or that the brake device 5 is not operated (brake disapproval). A target acceleration for brake non-permission follow-up calculated as a premise is calculated.

  The target acceleration calculation unit 22 determines a target acceleration S to be used when the vehicle traveling control device 1 controls the traveling of the host vehicle from the calculated plurality of tracking target accelerations. For example, the target acceleration calculation unit 22 selects the tracking target acceleration having the smallest value among the calculated tracking target accelerations, and determines the selected tracking target acceleration as the target acceleration S. Here, the target acceleration calculation unit 22 is connected to the following travel control unit 21 and the braking / driving force control unit 24. Therefore, when the preceding vehicle is recognized by the follow-up travel control unit 21, the position data of the recognized preceding vehicle is input to the target acceleration calculating unit 22. Then, the target acceleration S is determined from the plurality of target accelerations for tracking calculated based on the position data, and the determined target acceleration S is output to the braking / driving force control unit 24.

  The stop / hold control unit 23 is a stop / hold control unit, and performs a stop / hold control to apply a stop / hold braking force to the host vehicle by the brake device 5 serving as a braking force generation unit. This stop and hold control unit 23 performs stop and hold control immediately after the vehicle speed V of the host vehicle cannot be detected by the wheel speed sensor 4 that is the vehicle speed detecting means immediately before the stop of the host vehicle. The stop / hold control unit 23 includes a switching unit 23a, a switching interval setting unit 23b, and a counter 23c. The stop holding control unit 23 is connected to the wheel speed sensor 4 and the target acceleration calculation unit 22.

  The switching unit 23a is a switching unit, and a braking force applied to the host vehicle by the brake device 5 serving as a braking force generating unit from a non-detectable state in which the vehicle speed of the host vehicle cannot be detected by the wheel speed sensor 4 serving as a vehicle speed detecting unit. Is switched from the deceleration braking force to the stop holding braking force. Immediately before entering the undetectable state, that is, immediately before stopping the own vehicle, the follow-up running control unit 21 applies a deceleration braking force for stopping the own vehicle to the own vehicle by the brake device 5 serving as a braking force generating means. . Accordingly, the switching unit 23 a switches the braking force applied to the host vehicle by the brake device 5 from the deceleration braking force to the stop holding braking force after the vehicle speed of the host vehicle cannot be detected by the wheel speed sensor 4. In this embodiment, when the vehicle speed V of the host vehicle is detected by the wheel speed sensor 4, the switching section 23a outputs the input target acceleration S to the braking / driving force control section 24 as it is, and the wheel speed sensor 4, when the vehicle speed V of the host vehicle is no longer detected, the output of the input target acceleration S to the braking / driving force control unit 24 is stopped, and the stop holding control is started, that is, the stop holding control is turned on. An ON signal is output to the braking / driving force control unit 24.

  The switching interval setting unit 23b is a switching interval setting unit, and after the vehicle speed of the host vehicle cannot be detected by the wheel speed sensor 4 serving as a vehicle speed detection unit, the brake device 5 serving as a braking force generation unit is disabled. Thus, the switching interval T until the braking force applied to the host vehicle is switched from the deceleration braking force to the stop holding braking force is set. The switching interval setting unit 23b sets the switching interval T based on the magnitude of the braking force applied to the host vehicle in the undetectable state. Although not shown, the switching interval setting unit 23b is connected to the switching unit 23a. In this embodiment, the switching interval setting unit 23b uses the magnitude of the target acceleration S calculated by the target acceleration calculation section 22 as the magnitude of the braking force applied to the host vehicle, and sets the magnitude of the target acceleration S. Based on this, the switching interval T is set, and the set switching interval T is output to the switching unit 23a. For example, the magnitude of the calculated target acceleration S input from the target acceleration calculation unit 22 and a switching interval map based on the target acceleration S and the switching interval T stored in advance in a storage unit (not shown) as storage means. From this, the switching interval T is calculated.

  The counter 23c is a counting unit, and measures an elapsed time since the vehicle speed of the host vehicle cannot be detected by the wheel speed sensor 4 serving as a vehicle speed detection unit. The counter 23c is connected to the switching unit 23a (not shown). In this embodiment, the counter 23c counts when the vehicle speed of the host vehicle cannot be detected by the wheel speed sensor 4 as vehicle speed detection means, and outputs the count time t to the switching unit 23a.

  The braking / driving force control unit 24 is a braking / driving force control means, calculates a braking / driving force to be given to the host vehicle based on the target acceleration S calculated by the target acceleration calculating unit 22, and based on the calculated braking / driving force. Thus, at least one of the brake device 5 serving as the braking force generating means and the engine 6 serving as the driving force generating means is controlled. The braking / driving force control unit 24 is connected to the brake device 5 and the engine 6. In this embodiment, the braking / driving force control unit 24 receives the target acceleration input from the target acceleration calculation unit 22 via the stop holding control unit 23 when the vehicle speed V of the host vehicle is detected by the wheel speed sensor 4. S, the braking / driving force, that is, the following braking / driving force (deceleration braking force) based on the braking / driving force map based on the mass of the host vehicle stored in the storage unit in advance and the target acceleration S and the mass of the host vehicle. Is also included). The braking / driving force control unit 24 selects and controls at least one of the brake device 5 and the engine 6 in order to give the calculated following braking / driving force to the host vehicle. For example, the braking / driving force control unit 24 selects the engine 6 and applies the acceleration driving force for accelerating the own vehicle to the own vehicle out of the following braking / driving force, and will be described later based on the calculated acceleration driving force. The valve opening of the throttle valve 62 is calculated. The calculated valve opening is output to the throttle actuator 61 of the engine 6. On the other hand, the braking / driving force control unit 24 selects the brake device 5 when the deceleration braking force for stopping the host vehicle among the following braking / driving forces is applied to the host vehicle, and will be described later based on the calculated deceleration braking force. The target hydraulic pressure given by the brake body 53 to be calculated is calculated. The calculated target hydraulic pressure is output to the brake control device 51 of the brake device 5.

  Further, in this embodiment, the braking / driving force control unit 24 is input from the stop holding control unit 23 by turning on the stop holding control when the vehicle speed V of the host vehicle is no longer detected by the wheel speed sensor 4. Based on the control ON signal, the brake device 5 is selected, and a target hydraulic pressure capable of giving the host vehicle a stop holding braking force for holding the stop state of the host vehicle is calculated. The calculated target hydraulic pressure is output to the brake control device 51 of the brake device 5. Here, the stop holding braking force is larger than the deceleration braking force, that is, the target oil pressure applied to the brake body 53 is large. Further, the stop holding braking force may be set according to a stop state of the host vehicle, for example, a road surface gradient.

  Here, the control device 2 includes an input / output port (I / O) (not shown), a processing unit, and a storage unit as a storage unit. An input / output port (not shown) is connected to the various sensors and the various devices, and inputs data output from the various sensors to the control device 2, and outputs control signals from the control device 2 to the various devices. It is. A processing unit (not shown) includes a RAM (Random Access Memory) and a CPU (Central Processing Unit). This processing unit is realized by loading a program based on the vehicle travel control method into, for example, a RAM and executing the program. In addition, a storage unit (not shown) is configured by a ROM (Read Only Memory), a RAM, or a combination thereof. The storage unit stores various maps such as the switching interval map and the braking / driving force map, and data of the host vehicle such as the mass of the host vehicle.

  The millimeter wave radar 3 is a preceding vehicle detection means for detecting a preceding vehicle, and detects the position of an object existing in the traveling direction of the host vehicle. The millimeter wave radar 3 detects the position of the object by a detection method using millimeter waves, and the detected position data of the object is output to the follow-up travel control unit 21 of the control device 2. The millimeter wave radar 3 is attached to the center of the front portion of the host vehicle, for example, the front grill. Here, the millimeter wave radar 3 emits a millimeter wave, emits the millimeter wave from a front surface of the host vehicle in a predetermined range in the traveling direction, and receives the millimeter wave reflected by an object existing in the traveling direction of the host vehicle. . Then, the millimeter wave radar 3 calculates the distance from the millimeter wave radar 3 to the object existing in the traveling direction of the host vehicle by measuring the time from emission to reception. Further, the millimeter wave radar 3 can calculate the relative velocity with respect to the object by using the Doppler effect. In addition, the millimeter wave radar 3 detects the direction of the millimeter wave that is received with the strongest reflection among the received millimeter waves, and calculates the angle formed by the traveling direction of the host vehicle and the direction of the object from that direction. That is, when the position of the object is detected by the millimeter wave radar 3, the distance, relative speed, and angle to the object are input to the follow-up traveling control unit 21 of the control device 2 as detected object position data. It will be. The preceding vehicle detection means for detecting the preceding vehicle is not limited to the millimeter wave radar 3, and for example, image data obtained by capturing the traveling direction of the own vehicle with a radar, a stereo camera or the like using a laser or an infrared ray is used. An image recognition apparatus or the like may be used.

  The wheel speed sensor 4 detects the vehicle speed V of the host vehicle and is attached to the wheel of the host vehicle. The vehicle speed V detected by the wheel speed sensor 4 is output to at least the stop / hold control unit 23 of the control device 2, and the stop / hold control by the stop / hold control unit 23 is determined to be ON / OFF, that is, detected by the switching unit 23a. It is used for switching from the deceleration braking force to the stop holding braking force after the lapse of the switching interval T from the disabled state. Here, the wheel speed sensor 4 cannot detect an extremely low vehicle speed (for example, 1 km / h). Accordingly, when the actual actual vehicle speed of the host vehicle is extremely low, the vehicle speed V is not detected by the wheel speed sensor 4, so the stop holding control unit 23 determines that the wheel speed sensor 4 is stopped when the host vehicle is stopped. It is determined that the vehicle speed, that is, 0 km / h is detected. That is, it is determined that the vehicle speed of the host vehicle cannot be detected by the wheel speed sensor 4 serving as the vehicle speed detection means and the vehicle is in a state where it cannot be detected. The vehicle speed V detected by the wheel speed sensor 4 is also output to the target acceleration calculation unit 22 (not shown), and is used when calculating a plurality of tracking target accelerations.

  The brake device 5 is a braking force generating means that generates a braking force, applies the braking force to the host vehicle, and decelerates the host vehicle. That is, the brake device 5 generates a deceleration braking force or a stop holding braking force, applies the deceleration braking force or the stop holding braking force to the host vehicle, and stops the host vehicle or holds the stop state of the host vehicle. Is. The brake device 5 includes a brake control device 51, a brake actuator 52, and a brake body 53. The brake control device 51 controls the operation of the braking system, for example, controls the operation of the brake actuator 52 connected to the brake control device 51. Further, the brake control device 51 operates the brake actuator 52 with a target hydraulic pressure based on a depression amount of a brake pedal (not shown) by a driver and a traveling state of the host vehicle. The brake control device 51 can also operate the brake actuator 52 by the target hydraulic pressure calculated by the braking / driving force control unit 24 of the control device 2. The brake actuator 52 controls the hydraulic pressure to the brake body 53 that operates by hydraulic pressure. The brake body 53 applies a braking force to the host vehicle based on the hydraulic pressure controlled by the brake actuator 52. That is, the brake control device 51 controls the hydraulic pressure generated by the brake actuator 52. Here, the brake main body 53 is disposed so as to be paired with each wheel of the host vehicle. As this brake main body 53, there exists a hydraulic brake which act | operates with oil_pressure | hydraulic, such as a disk brake or a drum brake, for example.

  Here, when the driver depresses the brake pedal, the brake device 5 calculates the target oil pressure corresponding to the depression amount, and operates the brake actuator 52 so as to generate the target oil pressure. A target hydraulic pressure is applied to 53, assisting the driver in generating braking force, and assisting the driver in decelerating the host vehicle. Further, in the brake device 5, even if the driver does not depress the brake pedal, the brake actuator 52 is operated by the brake control device 51 by the target hydraulic pressure calculated by the braking / driving force control unit 24, and the target hydraulic pressure is applied to the brake body 53. Can be applied to generate braking force, apply braking force to the host vehicle, and decelerate the host vehicle. That is, the brake device 5 gives a deceleration braking force (included in the following braking / driving force) based on the calculated target acceleration S to the own vehicle during the follow-up running control, and applies the stop holding braking force to the own vehicle during the stop-holding control. To give. The brake control device 51 includes an input / output port (not shown), a processing unit, a storage unit, and the like, similar to the control device 2 described above.

  The engine 6 is a braking / driving force generating means that generates braking / driving force, mainly driving force, and applies the braking / driving force to the host vehicle to accelerate or decelerate the host vehicle. The engine 6 controls the braking / driving force by adjusting the amount of intake air taken into the engine 6. The engine 6 is provided with a throttle actuator 61 and a throttle valve 62. The throttle actuator 61 may have an ECU (vehicle travel control device 1 that controls the operation of the engine 6) that controls the operation of the engine 6 based on the accelerator opening of an accelerator pedal (not shown) by the driver. ) Is operated according to the valve opening degree of the throttle valve 62 calculated by (1). Further, the throttle actuator 61 is also operated by the valve opening calculated by the braking / driving force control unit 24 of the control device 2. The throttle valve 62 has a valve opening controlled by the operation of the throttle actuator 61, and adjusts the intake air amount by the valve opening. Here, when the driver depresses the accelerator pedal, the engine 6 operates the throttle actuator 61 by the ECU, the valve opening of the throttle valve 62 is controlled, and the amount of intake air taken into the engine 6 is adjusted. A braking / driving force is generated, and this braking / driving force is applied to the host vehicle. Further, in the engine 6, even if the driver does not depress the accelerator pedal, the throttle actuator 61 is operated by the valve opening calculated by the braking / driving force control unit 24, and the valve opening of the throttle valve 62 is controlled. The amount of intake air taken into the engine 6 is adjusted to generate braking / driving force, and this braking / driving force is applied to the host vehicle. That is, the engine 6 gives a follow-up braking / driving force (follow-up drive force, follow-up braking force) based on the calculated target acceleration S to the own vehicle during the follow-up running control.

  Note that the components of the vehicle travel control device 1 are not limited to those described above, and an operation for detecting whether or not the driver has operated an operation lever (not shown) that performs various commands and various settings of the vehicle travel control device 1. A lever sensor, a brake sensor that detects whether the driver has depressed a brake pedal (not shown), that is, whether or not the driver is willing to brake, a shift position sensor that detects a shift position, and an accelerator (not shown) by the driver An accelerator pedal sensor that detects whether the pedal is depressed, that is, whether or not the driver is willing to accelerate may be included.

  Further, the braking / driving force generating means is not limited to the engine 6 and may include a transmission (not shown). The engine 6 is connected to a transmission that transmits the output of the engine 6, that is, the braking / driving force to each wheel (not shown). The transmission device controls the transmission. The transmission is composed of a valve body and a transmission. The valve body is operated by a shift position calculated by the ECU based on an operation of a shift lever (not shown) by the driver or an accelerator opening of an accelerator pedal (not shown) by the driver. Further, the valve body is also operated by the shift position calculated by the braking / driving force control unit 24 of the control device 2. The transmission changes the gear ratio between the engine 6 and each wheel by the operation of the valve body, and changes, that is, adjusts the driving force or braking force generated by the engine 6. Here, in the transmission, when the driver operates the shift lever or the driver steps on the accelerator pedal, the valve body is operated by the ECU, the transmission ratio is changed by the transmission, and the braking / driving force generated by the engine 6 is generated. Adjust. Further, the transmission operates the valve body according to the shift position calculated by the braking / driving force control unit 24 without the operation of the shift lever or the depression of the accelerator pedal by the driver, and the gear ratio is changed by the transmission. And the braking / driving force can be generated by adjusting the driving force or braking force generated by the engine 6.

  Next, a vehicle travel control method using the vehicle travel control apparatus 1 according to the present invention will be described. FIG. 2 is a flowchart showing an example of the operation of the vehicle travel control device according to the present invention. FIG. 3 is an operation explanatory diagram of the vehicle travel control device according to the present invention. FIG. 4 is a diagram showing the relationship between the target acceleration S and the switching interval T. Note that the vehicle travel control by the vehicle travel control device 1 is performed every control cycle of the vehicle travel control device 1.

  First, as shown in FIG. 2, the control device 2 determines whether or not the vehicle traveling control is being performed (step ST1). Here, it is determined by the vehicle travel control device 1 whether or not ACC, which is vehicle travel control, in this embodiment, follow-up travel control is being performed. The control device 2 repeats until it is determined that the vehicle traveling control is being performed.

  Next, the stop holding control unit 23 of the control device 2 acquires the vehicle speed V of the host vehicle (step ST2). Here, the stop holding control unit 23 acquires the vehicle speed V of the host vehicle detected by the wheel speed sensor 4.

  Next, the stop holding control unit 23 of the control device 2 determines whether or not the acquired vehicle speed V is 0 (step ST3). Here, when the preceding vehicle is traveling at a speed at which the actual vehicle speed of the own vehicle does not become the extremely low vehicle speed V1 or less during the follow-up traveling control, the wheel speed sensor 4 can detect the vehicle speed V of the own vehicle. . Therefore, in this case, the stop holding control unit 23 determines that the acquired vehicle speed V is other than 0 in step ST3 shown in FIG.

Next, when it is determined that the acquired vehicle speed V is other than 0, the stop holding control unit 23 of the control device 2 turns off the stop holding control (step ST12).
). Here, the stop holding control unit 23 stops outputting the control ON signal to the braking / driving force control unit 24 or does not output this control ON signal. Here, when the vehicle traveling control is being performed, the follow-up traveling control unit 21 recognizes the preceding vehicle from the position data of the object input from the millimeter wave radar 3, and uses the recognized preceding vehicle position data as the target acceleration calculating unit. 22 to output. The target acceleration calculation unit 22 calculates a plurality of target accelerations for tracking based on the input position data of the preceding vehicle, determines a target acceleration S from the plurality of target accelerations for tracking, and sends it to the braking / driving force control unit 24. Output. The braking / driving force control unit 24 calculates the braking / driving force, here the following braking / driving force based on the inputted target acceleration S, and applies the following braking / driving force to the host vehicle in order to calculate the braking / driving force. At least one of the above is selected and controlled. As a result, the host vehicle follows the preceding vehicle recognized by the following traveling control unit 21.

  Next, the stop holding control unit 23 of the control device 2 sets the count time t of the counter 23c to 0 (step ST13). Here, when it is determined that the acquired vehicle speed V is other than 0, the stop holding control unit 23 outputs a reset instruction to the counter 23c, and sets the count number t of the counter 23c to 0. If it is determined that the vehicle speed V acquired by the stop and hold control unit 23 is other than 0, the operation in one control cycle of the vehicle travel control device 1 according to the present invention is finished, and the next control cycle is started.

  Here, when the preceding vehicle stops during the vehicle traveling control, that is, during the following traveling control, the own vehicle also stops while following the preceding vehicle. At this time, as shown in FIG. 3, the wheel speed sensor 4 cannot detect the vehicle speed V when the actual vehicle speed of the host vehicle is equal to or lower than the extremely low vehicle speed V1 (A3 portion shown in FIG. 3). B1 part). Therefore, in this case, the stop holding control unit 23 of the control device 2 determines that the acquired vehicle speed V is 0 in step ST3 shown in FIG. Here, the acquired vehicle speed V becomes 0 before the actual vehicle speed of the host vehicle becomes 0 km / h. Therefore, even if the acquired vehicle speed V becomes 0, the host vehicle is not actually stopped. In addition, when the vehicle speed V acquired for each control cycle of the vehicle travel control device 1 maintains 0 for a certain period, it may be determined that the acquired vehicle speed V is 0. When the wheel speed sensor 4 is attached to all the wheels, it may be determined that the acquired vehicle speed V is 0 when the vehicle speed V is no longer detected by all the wheel speed sensors 4.

  Next, when it is determined that the acquired vehicle speed V is 0, the stop holding control unit 23 of the control device 2 causes the counter 23c to count (step ST4). Here, as shown in FIG. 3, the counter 23 c starts counting after entering a detection impossible state where the vehicle speed of the host vehicle cannot be detected by the wheel speed sensor 4 (part C <b> 1 shown in FIG. 3). That is, the total time counted by the counter 23c, that is, the count time t is an elapsed time from the undetectable state.

  Next, the switching interval setting unit 23b of the stop holding control unit 23 acquires the target acceleration S (step ST5). Here, the stop holding control unit 23 acquires the target acceleration S calculated by the target acceleration calculation unit 22.

  Next, the switching interval setting unit 23b of the stop holding control unit 23 sets the switching interval T based on the acquired target acceleration S (step ST6). Here, the stop holding control unit 23 calculates the switching interval T from the acquired target acceleration S and the switching interval map based on the target acceleration S and the switching interval T stored in the storage unit (not shown). This switching interval map is obtained until the host vehicle can be surely stopped when the deceleration braking force based on the calculated target acceleration S is continuously applied to the host vehicle immediately after becoming undetectable. The time is set as the switching interval T (for example, when the calculated target acceleration S is S1, the time until the actual vehicle speed changes from A3 to A2 shown in FIG. 3 and the calculated target acceleration S is S2. In some cases, the time from the actual vehicle speed A3 to A4 shown in the figure). Further, as shown in FIG. 4, the switching interval map is set so that the switching interval T becomes smaller as the braking force applied to the host vehicle is larger, that is, as the calculated target acceleration S is smaller. For example, in the stop and hold control unit 23, when the calculated target acceleration S is S1, the set switching interval T is T1, but the target acceleration S is larger than this S1 (the braking force applied to the host vehicle is small). ) When S2, the set switching interval T becomes T2 longer than T1. The set switching interval T is appropriately stored in a storage unit (not shown).

  As described above, the target acceleration S calculated by the target acceleration calculation unit 22 during vehicle traveling control, that is, during follow-up traveling control, is in an undetectable state in which the vehicle speed of the host vehicle cannot be detected by the wheel speed sensor 4. May change from when the vehicle stops. For example, as shown in FIG. 3, even when the calculated target acceleration S is S1 when the detection becomes impossible, the target acceleration S is set to S1 in order to stop the driver's vehicle without feeling uncomfortable. May be larger than S2 (D1 portion shown in the figure), and may be returned to S1 after becoming S2 (D2 portion shown in the figure) to stop the host vehicle. In other words, the magnitude of the braking force applied to the host vehicle, that is, the deceleration braking force is once decreased (F1 portion shown in the figure), and then increased again (F2 portion shown in the figure) to stop the host vehicle. In some cases (braking force release control is performed).

  In this case, the acquired target acceleration S changes every control cycle of the vehicle travel control device 1. Accordingly, the switching interval setting unit 23b changes the switching interval T based on the change in the target acceleration S because the magnitude of the braking force applied to the host vehicle in the undetectable state, that is, the acquired target acceleration S changes. Will be. As described above, the switching interval map is set so that the switching interval T set by the switching interval setting unit 23b increases as the braking force applied to the vehicle in the undetectable state decreases. For example, when the target acceleration S acquired after becoming undetectable changes from S1 to S2 (D1 portion shown in the figure), that is, when the braking force applied to the vehicle in the undetectable state decreases, the switching interval setting unit 23b sets the switching interval T to T2 longer than T1 from S2 which is the acquired target acceleration S and the switching interval map shown in FIG. That is, the switching interval setting unit 23b increases the switching interval T when the braking force applied to the host vehicle in the undetectable state decreases.

  In other words, the switching interval setting unit 23b, which is the switching interval setting means, is in a non-detectable state when it becomes difficult for the host vehicle to decelerate after the vehicle speed V of the host vehicle is no longer detected by the wheel speed sensor 4, which is the vehicle speed detecting means. Since the time is longer until the host vehicle is stopped, the switching interval T is increased. Therefore, even if the magnitude of the braking force applied to the host vehicle from the undetectable state changes, the stop holding braking force described later is not applied to the host vehicle until the host vehicle is stopped. A shock when the vehicle is stopped can be suppressed.

Next, the switching interval setting unit 23b of the stop and hold control unit 23 determines whether or not the set switching interval T _(n) is _{equal to} or longer than the previously set switching interval T _{(n-1) as shown} in FIG. Is determined (step ST7).

Next, the switching interval setting unit 23b of the stop and hold control unit 23 sets the above setting when it is determined that the set switching interval T _(n) is _{equal to} or larger than the previously set switching interval T _(n-1). The switching interval T is maintained (step ST8). Here, the switching interval T is T _(n) .

On the other hand, when the switching interval setting unit 23b of the stop holding control unit 23 determines that the set switching interval T _(n) is less than the previously set switching interval T _(n-1) , the switching interval setting unit 23b is set as described above. The switching interval T is replaced with the previously set switching interval T _(n-1) (step ST9). Here, the switching interval T is T _(n-1) . That is, the switching interval setting unit 23b, which is a switching interval setting means, changes the switching interval T after the braking force applied to the host vehicle has decreased most from the undetectable state (the acquired target acceleration S has increased most). do not do. For example, as shown in FIG. 3, the target acceleration S acquired after entering the non-detectable state changes from S2 to S1 (D2 portion shown in the figure), that is, the braking force applied to the host vehicle in the non-detectable state. Even if it increases, the switching interval setting unit 23b maintains the longest switching time among the switching intervals T set up to the previous time.

  Accordingly, the switching interval setting unit 23b, which is the switching interval setting unit, changes when the magnitude of the braking force applied to the host vehicle changes after the vehicle speed V of the host vehicle is no longer detected by the wheel speed sensor 4 that is the vehicle speed detection unit. The switching interval T is changed based on the change, but the switching interval T is not changed after the braking force applied to the host vehicle is reduced most. That is, even if the braking force applied to the host vehicle increases from the smallest value, the switching interval T does not decrease from the switching interval T when the braking force applied to the host vehicle decreases most. Therefore, the vehicle travel control device 1 can surely place the host vehicle in the stop state during the switching interval T from the undetectable state. Thereby, since the stop holding braking force described later is not applied to the host vehicle until the host vehicle is stopped, a shock at the time of stopping the host vehicle can be suppressed.

  Next, the switching unit 23a of the stop and hold control unit determines whether or not the count time t is equal to or longer than the switching interval T (step ST10). Here, it is determined whether or not the elapsed time since the counter 23c is in the detection disabled state is equal to or longer than the switching interval T set by the switching interval setting unit 23b. Note that when the switching unit 23a determines that the count time t is less than the switching interval T, the vehicle travel control device 1 repeats the control cycle until the count time t becomes equal to or greater than the switching interval T.

  Next, when it is determined that the count time t is equal to or longer than the switching interval T, the switching unit 23a of the stop / hold control unit turns on the stop / hold control (step ST11). Here, when it is determined that the count time t is equal to or longer than the switching time T, that is, the actual vehicle speed of the host vehicle is 0 km / h, the switching unit 23a turns on the stop holding control and controls the input target acceleration S. The output to the driving force control unit 24 is stopped, and a control ON signal is output to the braking / driving force control unit 24. For example, when the removal control is performed as described above, as shown in FIG. 3, when the count time t becomes t2 which is equal to or longer than the switching interval T2, the stop holding control unit is turned ON (E portion shown in FIG. 3).

  The braking / driving force control unit 24 to which the control ON signal is input selects the brake device 5, calculates a target hydraulic pressure that can give the host vehicle a stop holding braking force that holds the stop state of the host vehicle, and calculates this The target hydraulic pressure is switched from the target hydraulic pressure that can apply the deceleration braking force based on the calculated target acceleration S to the host vehicle, and is output to the brake control device 51. Accordingly, the brake control device 51 operates the brake actuator 52 with the target hydraulic pressure that can give the stop holding braking force to the host vehicle, applies the brake actuator 53 with the hydraulic pressure, generates the stop holding braking force, and applies the stop holding braking force to the host vehicle. (F3 portion shown in the figure). That is, the switching unit 23a, which is a switching unit, becomes in a non-detectable state in which the vehicle speed of the host vehicle cannot be detected by the wheel speed sensor 4 which is a vehicle speed detection unit. After the set switching interval T elapses, the braking force applied to the host vehicle is switched from the deceleration braking force to the stop holding braking force by the brake device 5 serving as a braking force generating means.

  As described above, the vehicle travel control device 1 according to the present invention can detect the vehicle speed of the host vehicle by the wheel speed sensor 4 that is the vehicle speed detection means in a state where the deceleration braking force is applied to the host vehicle. When it becomes impossible, the braking force applied to the host vehicle is switched from the deceleration braking force to the stop holding braking force by the switching unit 23a which is a switching unit. The switching interval setting unit 23b which is a switching interval setting unit has a switching interval T, That is, the magnitude of the braking force that gives time to the host vehicle until the actual vehicle speed of the host vehicle reaches 0 km / h after the detection disabled state, that is, the target acceleration S calculated by the target acceleration calculating unit 22 in this embodiment. Set based on the size. Therefore, even if the vehicle speed of the host vehicle is no longer detected by the wheel speed sensor 4, the switching unit 23a decelerates until the switching interval T, that is, the actual vehicle speed of the host vehicle becomes 0 km / h, and the host vehicle stops. There is no switching from braking force to stop-holding braking force. As a result, the vehicle travel control device 1 can accurately estimate from when the vehicle speed V of the host vehicle is no longer detected by the wheel speed sensor 4 until the host vehicle is stopped. Further, since the stop holding braking force is not applied to the host vehicle until the host vehicle is stopped, a shock when the host vehicle is stopped can be suppressed.

  In the above embodiment, the braking force applied to the host vehicle is switched from the deceleration braking force to the stop holding braking force depending on the magnitude of the target acceleration S calculated by the target acceleration calculating unit 22. It is not limited to this. For example, the deceleration braking force may be switched to the stop holding braking force depending on the target hydraulic pressure calculated by the braking / driving force control unit 24 described above.

  As described above, the vehicle travel control device and the vehicle travel control method according to the present invention are useful for the vehicle travel control device and the vehicle travel control method for stopping the host vehicle during the vehicle travel control. It is suitable for suppressing a shock when the host vehicle stops immediately after starting.

It is a figure which shows the structural example of the vehicle travel control apparatus concerning this invention. It is a flowchart which shows an example of operation | movement of the vehicle travel control apparatus concerning this invention. It is operation | movement explanatory drawing of the vehicle travel control apparatus concerning this invention. It is a figure which shows the relationship between the target acceleration S and the switching space | interval T.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Vehicle travel control apparatus 2 Control apparatus 21 Follow-up travel control part 22 Target acceleration calculation part 23 Stop holding control part 23a Switching part (switching means)
23b Switching interval setting section (switching interval setting means)
23c counter 24 braking / driving force control unit 3 millimeter wave radar 4 wheel speed sensor (vehicle speed detection means)
5 Brake device (braking / driving force generating means)
6 Engine

Claims (7)

Braking force generating means for applying to the host vehicle a deceleration braking force for stopping the host vehicle or a stop-holding braking force for maintaining the stop state of the host vehicle;
Vehicle speed detection means for detecting the vehicle speed of the host vehicle;
Switching means for switching the braking force applied to the host vehicle by the braking force generating unit from a deceleration braking force to a stop holding braking force after the vehicle speed detecting unit becomes unable to detect the vehicle speed of the host vehicle. ,
A switching interval until the braking force applied to the host vehicle is switched from the deceleration braking force to the stop-holding braking force by the braking force generation unit after the detection disabled state is given to the host vehicle in the detection disabled state. Switching interval setting means for setting based on the magnitude of the braking force;
Equipped with a,
The vehicle travel control device, wherein the switching interval setting means changes the switching interval based on the change when the magnitude of the braking force applied to the host vehicle in the undetectable state changes . The vehicle travel control device according to claim 1 , wherein the switching interval setting means increases the switching interval when a braking force applied to the host vehicle in the undetectable state decreases. 3. The vehicle travel control device according to claim 2 , wherein the switching interval setting unit does not change the switching interval after the braking force applied to the host vehicle is most reduced from the undetectable state. The vehicle speed detecting means, the vehicle travel control device according to any one of claims 1-3, characterized in that the wheel speed sensor attached to the vehicle. A target acceleration calculating means for calculating at least a target acceleration of the host vehicle for applying a braking force to the host vehicle by the braking force generating unit;
The vehicle travel control apparatus according to any one of claims 1 to 4 , wherein the magnitude of the braking force applied to the host vehicle is the magnitude of the calculated target acceleration. The braking force generating means is
A brake body for applying a braking force to the host vehicle by hydraulic pressure;
A brake actuator for applying hydraulic pressure to the brake body;
A brake control device for calculating a target hydraulic pressure to be applied to the brake body;
With
The vehicle travel control apparatus according to any one of claims 1 to 5, wherein the magnitude of the braking force applied to the host vehicle is the magnitude of the calculated target hydraulic pressure. A procedure for determining whether the vehicle speed of the host vehicle can no longer be detected;
The stop holding for maintaining the stop state of the host vehicle from the deceleration braking force for stopping the host vehicle as the braking force applied to the host vehicle after entering the undetectable state where the vehicle speed of the host vehicle cannot be detected. A procedure for setting a switching interval until switching to a braking force based on the change when the magnitude of the braking force applied to the host vehicle in the undetectable state changes ;
A procedure for switching the braking force applied to the host vehicle from the deceleration braking force to the stop holding braking force after the switching interval has elapsed since the detection disabled state;
The vehicle travel control method characterized by including.

Images