JP2019189141A - Vehicle control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicle control device capable of accurately stopping at a target stop point by executing a braking control according to a traveling state of a vehicle. A vehicle control device calculates a braking distance based on a resistance parameter and an inertial parameter calculated while decelerating so that a vehicle speed becomes a predetermined value when an automatic stop condition is satisfied, thereby making a map. A target stop point is set from a plurality of stop point candidates retrieved from the information. Then, the vehicle is decelerated according to the deceleration profile based on the resistance parameter and the inertial parameter, so that the braking control is performed so as to stop at the target stop point. [Selection diagram] Figure 1

Description

  The present invention relates to a vehicle control device that automatically stops a vehicle by executing braking control when an automatic stop condition is satisfied.

  2. Description of the Related Art A vehicle that performs vehicle control that automatically stops a vehicle by executing braking control when a predetermined automatic stop condition is satisfied in the traveling vehicle is known. As a system for performing this type of vehicle control, for example, a deadman system is known in which a traveling driver is monitored and the vehicle is automatically stopped when an abnormality is confirmed by the driver.

  For example, in Patent Document 1, in the above-described deadman system, when an abnormality occurs in the vehicle occupant state, the vehicle steering is controlled so that the lateral acceleration and the lateral jerk of the vehicle are below predetermined threshold values. Thus, it is described that the vehicle behavior in the automatic stop is supported.

Japanese Unexamined Patent Publication No. 2017-1520

  Conventionally, in a system that performs such automatic braking control, braking is performed according to a predetermined target deceleration profile that is set in advance when an automatic stop condition is satisfied. Here, the target deceleration profile is generally set uniformly assuming a typical driving state. However, the braking characteristics of the vehicle change depending on road surface conditions such as the gradient and friction of the traveling road, or the increase or decrease of the vehicle weight. Therefore, in the braking control based on the uniformly set target deceleration profile, the actual vehicle speed profile may deviate from the target deceleration profile, and the stop point may deviate from the target.

  At least one embodiment of the present invention has been made in view of the above-described circumstances, and a vehicle control device capable of stopping the vehicle accurately with respect to a target stop point by performing braking control according to the traveling state of the vehicle. The purpose is to provide.

In order to solve the above problems, a vehicle control device according to at least one embodiment of the present invention
A vehicle control device that automatically stops a vehicle by executing braking control when an automatic stop condition is satisfied,
A stop point candidate search unit for searching a plurality of stop point candidates from map information;
A parameter calculation unit that calculates a resistance parameter related to a running resistance of the vehicle and an inertia parameter related to the inertia of the vehicle while decelerating the vehicle speed to a predetermined value;
A braking distance calculating unit that calculates a braking distance of the vehicle based on the resistance parameter and the inertia parameter;
A target stopping point setting unit that sets a target stopping point based on the braking distance from the plurality of stopping point candidates;
A controller that performs the braking control to stop at the target stop point by decelerating from a braking start position set based on the braking distance according to a deceleration profile based on the resistance parameter and the inertia parameter;
Is provided.

  According to the above configuration, the resistance parameter and the inertia parameter are obtained while decelerating the vehicle speed to a predetermined value, and then the deceleration profile is determined by the resistance parameter and the inertia parameter when decelerating toward the target stop point. This makes it possible to perform accurate stop control.

It is a block diagram which shows the structure of the vehicle control apparatus which concerns on one Embodiment of this invention. It is a flowchart which shows the vehicle control method implemented with the vehicle control apparatus of FIG. 1 for every process. It is a flowchart of the 1st braking control. It is a graph which shows an example of a time change of vehicle movement distance and vehicle speed at the time of execution of the 1st braking control. It is a flowchart of the 2nd braking control. It is a graph which shows an example of the time change of the vehicle movement distance at the time of implementation of the 2nd braking control, and vehicle speed.

  Hereinafter, some embodiments of the present invention will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of the components described in the embodiments or shown in the drawings are not intended to limit the scope of the present invention, but are merely illustrative examples. Absent.

  FIG. 1 is a block diagram showing a configuration of a vehicle control device 1 according to an embodiment of the present invention. The vehicle control device 1 is a control unit mounted on a vehicle, and is configured, for example, by installing a predetermined program in an electronic arithmetic device. The vehicle on which the vehicle control device 1 is mounted includes any vehicle that can be driven by power output from a power source such as an internal combustion engine or an electric motor (motor). In the present embodiment, the vehicle is particularly driven by an occupant or a load. A commercial vehicle such as a truck or bus whose weight is likely to fluctuate will be described as an example.

  The vehicle is equipped with an automatic stop control device 2 for automatically stopping the vehicle when the automatic stop condition is satisfied. The automatic stop control device 2 is, for example, a deadman system, monitors the driver of the vehicle with a monitoring device (such as a camera) (not shown), determines that the automatic stop condition is satisfied when an abnormality occurs in the driver, Is transmitted to the vehicle control device 1. The vehicle control device 1 performs the braking control according to the command received from the automatic stop control device 2, so that the vehicle is controlled until the vehicle reaches a stop state.

  In the above-described embodiment, the vehicle equipped with the deadman system is described as the automatic stop control device 2, but another automatic stop control device may be mounted instead of or in addition to the deadman system. As the automatic stop control device, for example, an auto cruise control that automatically performs a braking control when the host vehicle approaches another vehicle or an obstacle on a constant speed traveling path may be employed.

  The vehicle control device 1 includes a vehicle speed detection unit 4 that detects the speed of the vehicle. The vehicle speed detection unit 4 detects the speed of the vehicle by acquiring a signal from a vehicle speed sensor 6 mounted on the vehicle.

  The vehicle control device 1 includes a storage unit 8 such as a memory. The storage unit 8 stores various types of information necessary for performing the control of the vehicle control device 1, and particularly stores the target deceleration profile 10. The target deceleration profile 10 is a typical speed change from the speed at the start of braking to the speed (zero) at the end of braking when braking control is performed by detecting an abnormality in the automatic stop control device 2. However, it is defined on the premise of typical driving conditions of the vehicle (such as friction and gradient of the road, vehicle weight, etc.). Particularly in the present embodiment, the target deceleration profile 10 is set to a profile (for example, a trapezoidal profile) in which the speed change is gentler in the vicinity of the braking start time and in the vicinity of the braking end time than those in the intermediate time. Thus, when the braking control is performed, the vehicle can be stopped with a stable behavior.

  The storage unit 8 stores map information 11. The map information 11 includes geographical information around the vehicle. In particular, stop point candidates where the vehicle can stop appropriately are registered in advance. The map information 11 stored in the storage unit 8 can be read out by the stop point candidate search unit 13, and the stop point candidate search unit 13 acquires the vehicle position information (for example, GPS signal) acquired by the position information acquisition unit 15. Based on the map information 11, the stop point candidates in the vicinity of the vehicle can be searched.

  The vehicle control device 1 includes a control unit 12 that performs braking control so that the speed of the vehicle follows the target deceleration profile 10 when the automatic stop condition is satisfied. Based on the deviation between the target speed calculated based on the target deceleration profile 10 and the measured value of the vehicle speed sensor 6 acquired by the vehicle speed detection unit 4, the control unit 12 controls the brake ECU 14 that performs drive control of the braking device. In contrast, feedback control is performed.

  The brake ECU 14 is a control unit that controls a brake system mounted on the vehicle, and is configured to exhibit a predetermined braking force in accordance with a control signal from the vehicle (control unit 12). In addition, various systems, such as a disc brake and a drum brake, can be adopted as a brake system to be controlled by the brake ECU 14.

  The control unit 12 is a PID controller having a transfer function f (x) including a gain K, and is predetermined with respect to an input value (deviation x from the measured value of the vehicle speed sensor 6 acquired by the vehicle speed detection unit 4). The control signal F is output. Here, the vehicle control device 1 includes a first correction unit 16 and a second correction unit 18 for correcting the transfer function f (x) of the control unit 12 according to the traveling state of the vehicle. The first correction unit 16 and the second correction unit 18 correct the transfer function f (x) of the control unit 12 based on the parameter calculated by the parameter calculation unit 19.

  The first correction unit 16 corrects the transfer function f (x) of the control unit 12 based on the resistance parameter G related to the running resistance of the vehicle. Here, the resistance parameter G is a parameter relating to the running resistance of the vehicle including road surface conditions such as the gradient and friction of the running road. Ask. A method for calculating the resistance parameter G will be described later.

  The second correction unit 18 obtains the inertia parameter M so that the deviation between the vehicle speed and the target deceleration profile 10 is minimized. Here, the inertia parameter M is a parameter related to the inertia of the vehicle including the vehicle weight, and the parameter calculation unit 19 calculates the vehicle speed and the target deceleration profile 10 based on the transfer function corrected by the first correction unit 16. Calculate to minimize the deviation. A method for calculating the inertia parameter M will be described later.

The transfer function f (x) of the control unit 12 is corrected by the resistance parameter G and the inertia parameter M obtained by the parameter calculation unit 19. As a result, the control signal F to the brake ECU 14 is expressed by the following equation: F = M · f (x) −G (1)
Is obtained. The brake ECU 14 is controlled based on the control signal F based on the transfer function f (x) corrected in this way, so that the braking characteristics due to road surface conditions such as the gradient and friction of the traveling road or the increase or decrease of the vehicle weight. It is possible to control the vehicle in consideration of the change.

  Then, the vehicle control method implemented with the vehicle control apparatus 1 which has the said structure is demonstrated. FIG. 2 is a flowchart showing the vehicle control method performed by the vehicle control device 1 of FIG.

  First, the vehicle control device 1 determines whether or not an automatic stop condition is satisfied in the automatic stop control device 2 (step S100). That is, the automatic stop control device 2 that is a deadman system determines whether or not an abnormality has occurred in the driver and the vehicle is to be stopped. Such a determination is made based on whether or not an abnormal signal serving as a trigger for starting the braking control in the vehicle control device 1 is acquired from the automatic stop control device 2.

  When it is determined that the automatic stop condition is satisfied (step S100: YES), the vehicle control device 1 prohibits the vehicle acceleration operation by the driver (step S101). Specifically, an acceleration operation by an acceleration pedal (not shown) and an ACC (auto cruise control) function are forcibly prohibited. Thereby, for example, when the driver falls into an abnormal state due to poor physical condition or the like, a situation where the vehicle is accelerated by an unintended vehicle operation is effectively avoided.

  Subsequently, the vehicle control device 1 determines whether or not there is an operation of the manual cancellation switch 21 by the driver (step S102). The manual cancellation switch 21 is a switch for canceling the following control execution by a driver's operation. Since the success / failure determination of the automatic stop condition in step S100 is automatically performed, when the driver determines that the determination of establishment of the automatic stop condition is incorrect, the driver operates the manual cancellation switch 21 to The control execution can be stopped and the vehicle can be returned to the normal state. Therefore, when there is an operation of the manual cancellation switch 21 (step S102: YES), the following control is not performed, and the series of processing ends (END).

  When there is no operation of a manual cancellation switch (step S102: YES), the stop point candidate search part 13 is the map information 11 memorize | stored in the memory | storage part 8, and the positional information position information of the vehicle acquired by the positional information acquisition part 15 Based on the above, a plurality of stop point candidates are searched (step S103). As described above, stop point candidates are registered in advance in the map information 11. For example, a plurality of stop point candidates existing within a predetermined range from the current position of the vehicle specified by the position information are extracted.

  Subsequently, the vehicle control device 1 determines whether or not the vehicle speed V detected by the vehicle speed detection unit 4 is greater than the reference speed Vth (step S104). The reference speed Vth is a threshold value for determining which of the following two braking controls (first braking control or second braking control) to be executed depending on the magnitude of the vehicle speed V. It is acquired by reading out what is stored in advance in the storage device.

  When the vehicle speed V is higher than the reference speed Vth (step S104: YES), the first braking control is performed (step S105). On the other hand, when the vehicle speed V is equal to or lower than the reference speed Vth (step S104: NO), the second braking control is performed (step S106). As described above, in this embodiment, two types of braking control are performed according to the magnitude relationship between the vehicle speed V and the reference speed Vth. The specific contents of the first braking control and the second braking control will be described in detail later.

  When the first braking control or the second braking control is performed, the vehicle speed gradually decreases and eventually reaches zero. At this time, it is determined whether or not the vehicle speed V has reached zero by continuously monitoring the vehicle speed V (step S107). The first braking control or the second braking control is continued until the vehicle speed V reaches zero. When the vehicle speed V becomes zero (step S107: YES), the vehicle control device 1 ends a series of processes (END).

<First braking control>
Subsequently, specific contents of the first braking control performed in step S105 will be described. FIG. 3 is a flowchart of the first braking control, and FIG. 4 is a graph showing an example of temporal changes in the vehicle moving distance and the vehicle speed when the first braking control is performed.

When the first braking control in step S105 starts at time t0, the vehicle control device 1 performs inertial traveling (free deceleration) from time t0 for a predetermined period Tw (step S200), and the parameter calculation unit 19 A resistance parameter G is calculated based on a change in vehicle speed during the predetermined period Tw (step S201). Here, the predetermined period Tw is a period required until the speed of the vehicle starts to decrease due to the braking force being exerted by the brake system driven and controlled by the brake ECU 14 (that is, the braking force is actually applied from the time when the braking control is started). Is set to be shorter than the period required for the
The predetermined period Tw is, for example, less than 1 second.

により行われる。ここでＭ０は慣性パラメータＭの初期値であり、ｋは反応を調整するゲイン、ｈは車両制御装置のサンプリングタイム、

は０秒からｔ_１までの車両移動距離、

は予め定義された望ましい反応をするモデルによる速度、

は

を積分した望ましい反応の移動距離であり、ｒ（ｔ）は目標減速プロファイルである。 The calculation of the resistance parameter G in step S201 is, for example,

Is done. Here, M0 is an initial value of the inertia parameter M, k is a gain for adjusting the reaction, h is a sampling time of the vehicle control device,

Vehicle movement distance of from 0 seconds to t _1,

Is a pre-defined model with the desired reaction,

Is

Is the desired reaction travel distance, and r (t) is the target deceleration profile.

  Subsequently, the parameter calculation unit 19 corrects the transfer function f (x) of the control unit 12 using the previously obtained resistance parameter G (step S202), and based on the corrected transfer function, the speed of the vehicle Inertia parameter M is calculated so that the deviation from the target deceleration profile 10 is minimized (step S203). Then, the transfer function is further corrected using the inertia parameter M (step S204).

  Here, the calculation of the inertia parameter M in step S204 is performed using the transfer function corrected by the resistance parameter G so that the deviation between the vehicle speed and the target deceleration profile 10 is minimized. Such a calculation is performed by a sequential calculation such as a least square method. In this embodiment, two types of correction parameters, the resistance parameter G and the inertia parameter M, are used. By specifying the resistance parameter G in step S201 first, one variable (inertia parameter M) is used in step S203. ) Only. Thereby, since the period and accuracy required for the sequential calculation can be improved, it is possible to realize an accurate and responsive braking control even under a situation such as an emergency stop.

  Subsequently, the control unit 12 performs first-stage braking based on the transfer function corrected by the first correction unit 16 and the second correction unit 18 using the resistance parameter G and the inertia parameter M calculated by the parameter calculation unit 19. Control is performed (step S205). The control signal F output from the transfer function corrected by the first correction unit 16 and the second correction unit 18 uses the resistance parameter G obtained in step S201 and the inertia parameter M obtained in step S203. It can be obtained from equation (1).

  Subsequently, the vehicle control device 1 determines whether or not the vehicle speed has reached a constant speed Vcc (step S206). That is, it is determined whether or not the vehicle has reached a predetermined constant speed traveling state by performing the above-described braking control.

  When the vehicle speed reaches the constant speed travel speed Vcc at time t1 (step S206: YES), the vehicle control device 1 maintains the constant speed travel state (step S207).

While the constant speed state is maintained, it is determined whether or not the inertia parameter M calculated in step S203 is smaller than the road state determination value Mth (step S208). When the inertia parameter M is smaller than the road state determination value Mth (step S208: YES), Amax1 (for example, −2.5 m / s ² ) is set as the maximum deceleration (step S209). On the other hand, when the inertia parameter M is equal to or greater than the road state determination value Mth (step S208: NO), Amax2 (for example, −1 m / s ² ) is set as the maximum deceleration (step S210).

  Subsequently, the braking distance calculation unit 20 calculates the braking distance d1 of the vehicle based on the resistance parameter G and the inertia parameter M calculated by the parameter calculation unit 19 (step S211). Such a calculation of the braking distance is performed under the constraint condition that the maximum deceleration Amax is the value set in step S209 or S210.

  Subsequently, the target stop point setting unit 22 sets the target stop point based on the braking distance d1 calculated in step S211 from the plurality of stop point candidates searched in step S103. In selecting a target point by the target stop point setting unit 22, a stop candidate point closest to the current point of the vehicle is first selected from the plurality of stop point candidates searched in step S103 (step S212). Here, the current location of the vehicle is specified by the location information (for example, GPS information) of the vehicle acquired by the location information acquisition unit 15.

  Subsequently, for the stop point candidate selected in step S212, a distance d from the current point of the vehicle is calculated (step S213), and it is determined whether the distance d is greater than the braking distance d1 estimated in step S211. (Step S214). If the distance d is greater than the braking distance d1 (step S214: YES), the target stopping point setting unit 22 can set the braking candidate point selected in step S213 as the target stopping point because the braking distance including a sufficient margin can be secured. (Step S215).

  On the other hand, when the distance d is equal to or less than the braking distance d1 (step S214: NO), the braking distance including a sufficient margin cannot be secured, so the plurality of stop point candidates set in step S103 are used to determine the current position of the vehicle. The next closest stop point candidate is selected again (step S216), and the determination in step S214 is performed again. Thereby, the target stop point setting part 22 can set the stop point candidate nearest to the current point of the vehicle as the target stop point within a range in which a sufficient braking distance can be secured.

  Subsequently, by monitoring the distance d from the current position of the vehicle to the target point, it is determined whether or not the distance d has become the braking distance d1 (step S217). When the distance d becomes the braking distance d1 at time t2 (step S217: YES), it is determined that the vehicle has reached the braking start position, and whether the vehicle traveling state (road gradient or friction coefficient) has changed. It is determined whether or not (step S218). When the traveling state of the vehicle has not changed from the constant speed traveling state (step S218: YES), the control unit 12 performs the second-stage braking control from the braking start position based on the resistance parameter G obtained in step S201. Implement (step S219). As a result, in the second-stage braking control from time t2, the braking control based on the resistance parameter G can be performed immediately after the start of deceleration (without a time lag), so that the vehicle can be accurately stopped at the target stop point. it can.

  On the other hand, when the traveling state of the vehicle has changed from the constant speed traveling state (step S218: NO), the control unit 12 replaces the resistance parameter G obtained in step S201 with a default value (zero) resistance parameter. Based on G, the second-stage braking control is performed (step S220). Thereby, when the running state of the vehicle changes, although the accuracy is lower than in step S219, it is possible to perform appropriate stop control with respect to the target stop point.

<Second braking control>
Subsequently, specific contents of the second braking control performed in step S106 will be described. FIG. 5 is a flowchart of the second braking control, and FIG. 6 is a graph showing an example of temporal changes in the vehicle moving distance and the vehicle speed when the second braking control is performed.

  When the second braking control in step S106 starts at time t0, the vehicle control device 1 performs inertial traveling (free deceleration) from time t0 (step S300), and the parameter calculation unit 19 determines the speed of the vehicle during inertial traveling. Based on the change, the resistance parameter G is calculated (step S301). At this time, gradient information on the road surface of the vehicle is recorded (step S302).

  Subsequently, the parameter calculation unit 19 inputs the previously obtained resistance parameter G to the vehicle model, and calculates the inertia parameter M by comparing the calculated value of the vehicle speed V by the vehicle model with the actually measured value (step S303). ).

  Subsequently, the vehicle control device 1 determines whether or not the speed of the vehicle that performs inertial traveling has reached the constant speed traveling speed Vcc (step S304). That is, it is determined whether or not the vehicle has reached a predetermined constant speed traveling state by performing the above-described braking control.

  When the vehicle speed reaches the constant speed travel speed Vcc at time t1 (step S304: YES), the vehicle control device 1 maintains the constant speed travel state (step S305).

  The process after step S306 is the same as that after step S208 in the first braking control. That is, the second braking control that is performed at a lower vehicle speed than the first braking control is that the first stage braking control from time t0 to time t1 is performed by free deceleration by inertial traveling. Different from 1 braking control. Also in this case, accurate stop control is possible by correcting the transfer function f (x) in the second stage braking control after time t2 by the resistance parameter G and the inertia parameter M calculated during the inertia traveling. It becomes.

  As described above, according to the present embodiment, the resistance parameter G and the inertia parameter M are obtained while decelerating the vehicle speed to the predetermined value Vcc, and then when decelerating toward the target stop point, The deceleration profile is corrected by the resistance parameter G and the inertia parameter M, and the stop control with high accuracy can be performed. Thus, by performing the braking control according to the running state of the vehicle, it is possible to provide a vehicle control device capable of stopping with high accuracy with respect to the target stop point.

  At least one embodiment of the present invention can be used for a vehicle control device that automatically stops a vehicle by executing braking control when an automatic stop condition is satisfied.

DESCRIPTION OF SYMBOLS 1 Vehicle control apparatus 2 Automatic stop control apparatus 4 Vehicle speed detection part 6 Vehicle speed sensor 8 Storage part 10 Target deceleration profile 11 Map information 12 Control part 13 Stop point candidate search part 15 Position information acquisition part 16 1st correction | amendment part 18 2nd correction | amendment Unit 19 Parameter calculation unit 20 Braking distance calculation unit 21 Manual cancellation switch 22 Target stop point setting unit

Claims (1)

A vehicle control device that automatically stops a vehicle by executing braking control when an automatic stop condition is satisfied,
A stop point candidate search unit for searching a plurality of stop point candidates from map information;
A parameter calculation unit that calculates a resistance parameter related to a running resistance of the vehicle and an inertia parameter related to the inertia of the vehicle while decelerating the vehicle speed to a predetermined value;
A braking distance calculating unit that calculates a braking distance of the vehicle based on the resistance parameter and the inertia parameter;
A target stopping point setting unit that sets a target stopping point based on the braking distance from the plurality of stopping point candidates;
A controller that performs the braking control to stop at the target stop point by decelerating from a braking start position set based on the braking distance according to a deceleration profile based on the resistance parameter and the inertia parameter;
A vehicle control device comprising:

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