JP5889757B2 - Vehicle control device - Google Patents

Description

  The present invention relates to a vehicle control device that controls a vehicle behavior to a target vehicle behavior according to a traveling state.

  Conventionally, in the technique described in Patent Document 1, when an accelerator operation is performed by the driver during yaw moment control or deceleration control, yaw moment control or deceleration control is terminated, and the driver's intention is given priority. By accelerating the vehicle, the vehicle can accelerate according to the driver's intention.

JP 2002-127888 A

However, the technique described in Patent Document 1 has a problem that when the driver steers during acceleration, the vehicle response to steering cannot be sufficiently obtained and the turning performance deteriorates. Furthermore, if the steering amount is large, the vehicle trajectory may deviate significantly from the driver's target travel trajectory, and the driver's intention to accelerate can be satisfied, but sufficient vehicle responsiveness is obtained. Therefore, as a result, there is a possibility that it is difficult to travel reflecting the driver's steering intention.
An object of the present invention is to provide a vehicle control device capable of obtaining a vehicle behavior according to a steering state of a driver.

  In order to achieve the above object, in the present invention, a yaw moment control for applying a braking force to the turning inner wheel to generate a yaw moment for the vehicle or a deceleration control for applying a braking force to the four wheels to generate a deceleration to the vehicle. When controlling the vehicle behavior so that the vehicle converges to the target lateral acceleration according to the steering state, the yaw moment control is performed in the steered state, and the deceleration control is performed in the predetermined steered state. It was decided to.

  Therefore, stabilization of the vehicle behavior during acceleration can be achieved.

1 is a system diagram of a vehicle control device according to a first embodiment. FIG. 2 is a control block diagram of the vehicle control device according to the first embodiment. 3 is a flowchart illustrating basic control contents according to the first exemplary embodiment. 3 is a flowchart showing the vehicle behavior control content of the first embodiment. FIG. 3 is a time chart showing vehicle response to steering input in the first embodiment and indicating presence / absence of vehicle behavior control. FIG. 6 is a time chart when a side slip occurs during steering according to the first embodiment. It is a time chart when steering of Example 1 is quick and vehicle traceability is bad. 6 is a time chart when the steering of Example 1 is fast, the vehicle traceability is poor, and a slow spin occurs. It is the schematic showing the control content of the vehicle behavior control process of Example 1. FIG.

[Example 1]
FIG. 1 is a system diagram illustrating a control configuration of the vehicle control device according to the first embodiment. The vehicle behavior controller 10 detects an accelerator pedal sensor 1 that detects an accelerator pedal operation amount Apo of a driver, a brake pedal sensor 2 that detects a brake pedal operation amount Bpedal, a wheel speed sensor 3 that detects a wheel speed Vw, and a yaw rate γ. Vehicle behavior control based on input signals from a yaw rate sensor 4 that detects a lateral acceleration ay, a longitudinal acceleration sensor 6 that detects longitudinal acceleration ax, and a steering angle sensor 7 that detects a steering operation amount θstr of a driver. Perform the operation. By various arithmetic processes, a braking force command Fw * is output to the brake actuator 20 that can control the braking force of each wheel.

  The brake actuator 20 is an electrically controlled device, and detects an actual actuator operation state (hereinafter referred to as an actuator state) by detecting a current value, a hydraulic pressure, or the like by a sensor such as a current sensor or a pressure sensor as necessary. It can be detected. In addition to vehicle behavior control (yaw moment control and deceleration control), which will be described later, it is determined that a side slip (excessive oversteer or understeer) has occurred when the side slip angle of the vehicle is equal to or greater than a predetermined angle. Implement anti-slip control (hereinafter referred to as ESC control) that suppresses excessive skidding. This ESC control is a conventionally known skid control process. For example, when oversteering, braking force is applied to the turning outer wheel side, and when understeering, braking force is applied to the turning inner wheel side. The details are omitted here.

  FIG. 2 is a control block diagram illustrating a vehicle behavior control process according to the first embodiment. In the driver operation detection unit 101, driver operation amounts detected by various sensors, for example, accelerator pedal operation amount Apo (accelerator opening, throttle opening, etc.), brake pedal operation amount Bpedal (stroke amount, master cylinder pressure, etc.), steering The steering angle θstr is detected. The vehicle state detection unit 102 detects yaw rate γ, lateral acceleration ay, longitudinal acceleration ax, and wheel speed Vw generated in the vehicle. The actuator state detection unit 103 detects an actuator state that is an operating state of various electromagnetic devices in the brake actuator 20.

  The vehicle behavior estimation unit 104 estimates the vehicle behavior with respect to the driver's operation, calculates an appropriate target yaw rate γ *, and estimates the side slip angular velocity dβ / dt, the vehicle body speed Vcar, and the road surface friction coefficient μ. The target yaw rate is set by a map or model estimation process by setting a target yaw rate appropriate for the vehicle according to the traveling state according to the vehicle speed and the steering angle. The side slip angle is an angle formed by the vehicle traveling direction and the tire rotation direction, and is appropriately calculated based on the vehicle model from the yaw rate and the lateral speed. The vehicle speed Vcar is calculated from the average value of the driven wheels among the wheel speed Vw of each wheel. The road surface friction coefficient μ is estimated from, for example, the difference between the deceleration and lateral acceleration based on the reference road surface friction coefficient and the actual deceleration and lateral acceleration.

  The target lateral acceleration calculation unit 105 calculates a target lateral acceleration ay * based on the operation state of the driver and the estimated vehicle behavior. The target lateral acceleration ay * is a value set based on the current vehicle speed Vcar, the steering operation amount θstr, and the road surface friction coefficient μ. As dt increases, a larger target is set, and as the road surface friction coefficient μ increases, a larger target is set. The lateral acceleration deviation calculator 106 calculates a deviation ay_err between the target lateral acceleration ay * calculated by the target lateral acceleration calculator 105 and the actual lateral acceleration ay detected by the lateral acceleration sensor 5.

  The target yaw moment calculation unit 107 calculates a target yaw moment M * based on the lateral acceleration deviation ay_err and the estimated skid angular velocity dβ / dt. This target yaw moment M * is calculated so as to increase as the lateral acceleration deviation ay_err increases and to decrease as the side-slip angular velocity dβ / dt increases. The large lateral acceleration deviation ay_err is because the lateral acceleration is not sufficiently generated due to insufficient turning, and thus it is necessary to generate a yaw moment for turning. Therefore, the target yaw moment M * is greatly corrected and the vehicle is turned. Further, a high skid accuracy dβ / dt is an unstable state as a vehicle. If a yaw moment is generated in such a case, there is a risk of causing a spin or the like. Therefore, the target yaw moment M * is corrected to be small to avoid spins and the like.

  The target deceleration calculation unit 108 calculates a target deceleration ax * based on the lateral acceleration deviation ay_err and the skid angular velocity dβ / dt. This target deceleration ax * is calculated so as to increase as the lateral acceleration deviation ay_err increases and as the side slip angular velocity dβ / dt increases. A large lateral acceleration deviation ay_err indicates that sufficient lateral acceleration has not occurred due to insufficient turning. Therefore, it is necessary to reduce the lateral acceleration deviation ay_err by reducing the target lateral acceleration ay * by generating deceleration. Therefore, the target deceleration ax * is largely corrected to decelerate and the target lateral acceleration ay * is reduced. In addition, a high skid accuracy dβ / dt is an unstable state of the vehicle, and if the vehicle speed is high in such a state, there is a risk of causing a spin or the like, so the target deceleration ax * is greatly corrected. To avoid spins.

  Each actuator target value calculation unit 109 calculates a target braking force 110 for each wheel based on the calculated target yaw moment M *, target deceleration ax *, and detected actuator state, and applies it to the brake actuator 20. Output. FIG. 9 is a schematic diagram illustrating the control contents of the vehicle behavior control process according to the first embodiment.

  If the absolute value of the lateral acceleration deviation is less than the predetermined value in a steered state (the angular speed of the steering angle θstr is greater than or equal to a predetermined speed), the vehicle's response to steering is considered to be slow. Turnability is obtained by applying a braking force to the turning inner wheel in accordance with the deviation between the target yaw rate γ * and the actual yaw rate γ. As a result, the side slip angular velocity dβ / dt is suppressed. Note that the yaw moment control is not performed if the steering is maintained (the steering steering angle θstr is less than the predetermined angular velocity).

If the absolute value of the lateral acceleration deviation is greater than or equal to a predetermined value, deceleration control is started in addition to yaw moment control to decelerate the vehicle and reduce the target lateral acceleration ay *, thereby making the lateral acceleration deviation ay_err The turnability is secured by reducing the size.
Even when the steering is maintained, if the lateral acceleration deviation ay_err is large, it is considered that the traceability of the vehicle is poor with respect to steering, so the deceleration control is performed while the yaw moment control is finished, and the vehicle target Improve traceability with respect to the trajectory.
In the case of the first embodiment, the control is basically continued even when the acceleration request is made during the vehicle behavior control as in the prior art. The yaw moment control and deceleration control are determined to be executed or stopped according to the steering state and the lateral acceleration deviation, and if there is an ESC control intervention based on the side slip angular velocity, the yaw moment control and deceleration control are performed in advance. finish.

FIG. 3 is a basic flowchart showing the vehicle behavior control process according to the first embodiment.
In step S1, input signal processing is executed. Specifically, the driver operation detection unit 101, the vehicle state detection unit 102, and the actuator state detection unit 103 read various sensor signals.
In step S2, the vehicle behavior state is estimated. Specifically, the vehicle behavior estimation unit 104 calculates an appropriate target yaw rate γ *, and estimates the skid angular velocity dβ / dt, the vehicle body speed Vcar, and the road surface friction coefficient μ.
In step S3, vehicle behavior control calculation processing is performed. Specific contents will be described later.
In step S4, output signal processing for outputting a command signal to the brake actuator 20 based on the calculation result is executed.

FIG. 4 is a flowchart illustrating a vehicle behavior control process according to the first embodiment.
In step S21, the target lateral acceleration calculation unit 105 calculates the lateral acceleration based on the driver request.
In step S22, correction according to the road surface friction coefficient μ is performed, and a final target lateral acceleration ay * is calculated.
In step S23, a lateral acceleration deviation ay_err is calculated.
In step S24, it is determined whether or not the absolute value of the lateral acceleration deviation is greater than or equal to a predetermined value. On the other hand, if the absolute value of the lateral acceleration deviation is equal to or greater than the predetermined value, it is determined that vehicle behavior control is necessary, and the process proceeds to step S25.
In step S25, a target yaw moment M * is calculated. Specifically, based on the deviation between the target yaw rate γ * calculated by the vehicle behavior estimation unit 104 and the actual yaw rate γ, the yaw moment M * of the vehicle necessary to achieve the target yaw rate γ * is calculated.
In step S26, the target deceleration ax * is calculated based on the lateral acceleration deviation ay_err.

  In step S27, when the absolute value of the lateral acceleration deviation is less than the predetermined value in the steered state, first, the turning behavior of the vehicle behavior is obtained by the yaw moment control. As a result, the side slip angular velocity dβ / dt is suppressed. If the absolute value of the lateral acceleration deviation continues to be greater than or equal to the predetermined value, the deceleration control is started to decelerate the vehicle, and the target lateral acceleration ay * is reduced. The turning ability of the vehicle is secured by reducing ay_err. If it is in the steering holding state, the yaw moment control is terminated, and it is dealt with by deceleration control as necessary.

(Operation of vehicle behavior control processing)
Hereinafter, the operation based on the control flow will be described with reference to FIGS. Note that the steering angle and the target lateral acceleration are values that change in a substantially one-to-one correspondence. If the steering angle is not described on the time chart, it is regarded as a value that changes in the same phase as the target lateral acceleration.

FIG. 5 is a time chart showing a case where no control is performed (non-control) and a case where the yaw moment control is performed when the lateral acceleration deviation is less than a predetermined value.
When the driver starts steering at time t1, the vehicle enters a steered state, and the vehicle behavior starts to change with a predetermined response delay.
Since a lateral acceleration deviation occurs at time t2, yaw moment control is performed according to the calculated target yaw moment, and a braking force is generated on the turning inner wheel to obtain a turning ability.
At time t3, the yaw moment control is finished when the steered state is shifted to the steered state. In the case of FIG. 5, it can be seen that the lateral acceleration deviation can be suppressed by the yaw moment control as compared with the non-control case. Further, since the lateral acceleration deviation is suppressed, the actual lateral acceleration can be made to follow the target lateral acceleration when the steering is maintained, and the vehicle behavior according to the driver's intention is achieved.

FIG. 6 is a time chart when a side slip occurs during the vehicle behavior control of the first embodiment.
When the driver starts steering at time t1, the vehicle enters a steered state, and the vehicle behavior starts to change with a predetermined response delay.
Since a lateral acceleration deviation occurs at time t2, yaw moment control is performed according to the calculated target yaw moment.
If the skid angular velocity is equal to or greater than a predetermined angle at time t21, it is determined that oversteer has occurred due to the yaw moment control, and the yaw moment control is terminated.
At time t22, the ESC control operation is started. As a result, a target yaw moment toward the understeer side is set, thereby stabilizing the vehicle behavior.

FIG. 7 is a time chart when the steering speed is high and the vehicle traceability is poor when the vehicle behavior control of the first embodiment is performed.
When the driver starts steering at time t1, the vehicle enters a steered state, and the vehicle behavior starts to change with a predetermined response delay.
Since a lateral acceleration deviation occurs at time t2, yaw moment control is performed according to the calculated target yaw moment.
When the lateral acceleration deviation becomes equal to or greater than a predetermined value at time t31, it is determined that the lateral acceleration deviation cannot be suppressed only by yaw moment control, and deceleration control is started. As a result, the turning performance is ensured by decelerating. At time t32, the yaw moment control ends when the steering state is shifted to the steering holding state. However, since the lateral acceleration deviation is still more than the predetermined value, the vehicle behavior is stabilized by continuing the deceleration control.
At time t33, the deceleration control is terminated when the lateral acceleration deviation becomes less than a predetermined value. Thereby, a vehicle behavior can be stabilized.

FIG. 8 is a time chart when a slow spin occurs in a state where the steering speed is high and the vehicle traceability is poor when the vehicle behavior control of the first embodiment is performed.
Since the time t1 to the time t32 is the same as the description of FIG. 7, the description is omitted.
At time t41, when the deceleration control is continued, the vehicle deceleration control is terminated if a skid angle occurs more than a predetermined value.
At time t42, when it is detected that the vehicle starts to spin slowly, the operation of ESC control is started. Thereby, the slow spin of the vehicle is suppressed.

As described above, the effects listed below are obtained in the first embodiment.
(1) A driver operation detection unit 101 (steering state calculation unit) that calculates a driver's steering state, a target lateral acceleration calculation unit 105 that calculates a target lateral acceleration from the calculated steering state, and the vehicle are generated. A vehicle state detection unit 102 (actual lateral acceleration calculation unit) that calculates the actual lateral acceleration, a lateral acceleration deviation calculation unit 106 that calculates a deviation between the target lateral acceleration and the actual lateral acceleration, and a vehicle that applies braking force to the turning inner wheel. A target yaw moment calculation unit 107 (yaw moment control) that generates a yaw moment with respect to the vehicle or a target deceleration calculation unit 108 (deceleration control) that generates braking on the vehicle by applying braking force to the four wheels. Has an actuator target value calculation unit 109 (vehicle behavior control unit) that controls the vehicle behavior so as to converge to the calculated target lateral acceleration. The actuator target value calculation unit 109 changes the calculated steering state. Rudder state Sometimes performed yaw moment control, calculated steering state is when the predetermined holding steering state to implement the deceleration control.
Therefore, even when the driver depresses the accelerator during vehicle behavior control and there is a request for acceleration, the vehicle behavior during acceleration can be stabilized by continuing the vehicle behavior control. That is, even in a scene where the vehicle is accelerating according to the acceleration request, the turning performance can be ensured by the yaw moment control in the steered state, and the traceability can be improved by the deceleration control in the steered state.

(2) A driver operation detection unit 101 (steering state calculation unit) that calculates the driver's steering state, a target lateral acceleration calculation unit 105 that calculates a target lateral acceleration from the calculated steering state, and the vehicle are generated. A vehicle state detection unit 102 (actual lateral acceleration calculation unit) that calculates the actual lateral acceleration, a lateral acceleration deviation calculation unit 106 that calculates a deviation between the target lateral acceleration and the actual lateral acceleration, and a vehicle that applies braking force to the turning inner wheel. Yaw moment control performed by a target yaw moment calculation unit 107 (yaw moment control means) that generates a yaw moment with respect to the vehicle, and a target deceleration calculation unit 108 that applies braking force to the four wheels to generate deceleration in the vehicle When the calculated lateral acceleration deviation is less than the predetermined deviation, the yaw moment control is executed, and when the calculated lateral acceleration deviation is more than the predetermined deviation, the deceleration control is executed. The actuator target value calculation unit 109 (vehicle behavior control unit) and the actuator target value calculation unit 109 that control the vehicle behavior so that both are converged to the calculated target lateral acceleration, and the actuator target value calculation unit 109 Sometimes yaw moment control is performed, and deceleration control is performed when the calculated steering state is a predetermined steering state.
Therefore, even when there is a request for acceleration in a steered state, if the lateral acceleration deviation occurs, the vehicle behavior can be stabilized by securing the turning ability by the yaw moment control. Further, when the lateral acceleration deviation increases due to an acceleration request, the traceability can be improved by performing deceleration control.

(3) A vehicle behavior estimation unit 104 (side slip angular velocity calculation unit) that calculates the side slip angular velocity of the vehicle, and a target yaw moment calculation unit 107 that corrects the control amount of each control unit according to the calculated side slip angular velocity. A target deceleration calculation unit 108 (control amount correction means).
Specifically, when the skid angular velocity is large, the target yaw moment is reduced and the target deceleration is corrected to be large. As a result, the vehicle behavior can be stabilized.

1 accelerator pedal sensor 2 brake pedal sensor 3 wheel speed sensor 4 yaw rate sensor 5 lateral acceleration sensor 6 longitudinal acceleration sensor 7 steering angle sensor 10 vehicle behavior control controller 20 brake actuator
101 Driver operation detector
102 Vehicle state detector
103 Actuator status detector
104 Vehicle behavior estimation unit
105 Target lateral acceleration calculator
106 Lateral acceleration deviation calculator
107 Target yaw moment calculator
108 Target deceleration calculation unit
109 Actuator target value calculator

Claims (3)

A steering state calculation unit for calculating the steering state of the driver;
A target lateral acceleration calculation unit for calculating a target lateral acceleration from the calculated steering state;
An actual lateral acceleration calculation unit for calculating an actual lateral acceleration generated in the vehicle;
A lateral acceleration deviation calculating unit for calculating a deviation between the target lateral acceleration and the actual lateral acceleration;
The vehicle performs the yaw moment control for applying a braking force to the turning inner wheel and generating a yaw moment for the vehicle, or the deceleration control for applying a braking force to the four wheels and generating a deceleration to the vehicle. A vehicle behavior control unit for controlling the vehicle behavior so as to converge to the acceleration;
Have
The vehicle behavior control unit performs the yaw moment control when the calculated steering state is a steered state, and performs the deceleration control when the calculated steering state is a predetermined hold state. A vehicle behavior control device. A steering state calculation unit for calculating the steering state of the driver;
A target lateral acceleration calculation unit for calculating a target lateral acceleration from the calculated steering state;
An actual lateral acceleration calculation unit for calculating an actual lateral acceleration generated in the vehicle;
A lateral acceleration deviation calculating unit for calculating a deviation between the target lateral acceleration and the actual lateral acceleration;
A yaw moment control means for applying a braking force to the turning inner wheel and generating a yaw moment for the vehicle;
Deceleration control means for applying braking force to the four wheels to generate deceleration on the vehicle;
When the calculated steering state is a steered state and the calculated lateral acceleration deviation is less than a predetermined deviation , control by the yaw moment control means is performed, and the calculated steering state is maintained at a predetermined level. When the calculated lateral acceleration deviation is greater than or equal to a predetermined deviation , control by the deceleration control means is performed, and the vehicle behavior is adjusted so that the vehicle converges to the calculated target lateral acceleration. A vehicle behavior control unit to be controlled;
Vehicle control apparatus characterized by having a. The vehicle control device according to claim 2,
A skid angular velocity calculating unit for calculating a skid angular velocity of the vehicle;
Control amount correction means for correcting control amounts of the yaw moment control means and the deceleration control means in accordance with the calculated sideslip angular velocity,
A vehicle control device comprising:

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