JP3851049B2 - Vehicle behavior control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize stabilization control with excellent safety at low cost by means of a vehicle behavior control device provided with a means for estimating vehicle behavior from a vehicle state quantity and a means for controlling brake pressure to each wheel and engine torque to a drive wheel to stabilize the abnormal vehicle behavior. SOLUTION: This vehicle behavior control device is provided with a means (steps 8, 9, 12) for canceling control of the engine torque to the drive wheel when a vehicle is in a state in which it moves straight forward or in a state close to this state.

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vehicle behavior control device for a connected vehicle .
[0002]
[Prior art]
In recent years, when abnormal vehicle behavior (excessive oversteer, excessive understeer) is determined from vehicle state quantities as a means to control vehicle motion characteristics, particularly turning characteristics, wheel braking force (brake pressure and driving force) is independent. It is known that the yaw moment in the direction of reestablishing (stabilizing) the abnormal vehicle behavior is positively generated by controlling (SAE paper-982782 etc.).
[0003]
Among them, in Japanese Patent Application Laid-Open No. 7-108912, the driver's accelerator operation is detected in order to avoid interference between the vehicle behavior stabilization control and the vehicle behavior recovery operation (accelerator operation, etc.) performed by the driver. And release the stabilization control of the vehicle behavior to leave the abnormal vehicle behavior rework to the driver's skill (for example, only the control of the driving force is released and the control of the brake pressure for the wheels other than the driving wheel is continued) What is made is disclosed.
[0004]
[Problems to be solved by the invention]
When the driver reestablishes the vehicle behavior, it depends on the accelerator operation and the steering wheel operation. Therefore, the driver needs considerable skill to be able to stabilize the vehicle behavior. In the conventional example described above (Japanese Patent Laid-Open No. 7-108912), an unskilled driver may perform an accelerator operation suddenly when an abnormal vehicle behavior occurs regardless of the level of skill and skill of the driver. Even in this case, the stabilization control of the vehicle behavior is cancelled. In addition, during the stabilization control of the vehicle behavior, since it is not known when the driver's accelerator operation is started, the correction means for gradually changing the target braking force of each wheel in order to ensure smooth switching of the control And the control system configuration is complicated, which may lead to a significant increase in cost.
[0005]
The present invention has been made in consideration of such inconveniences. In particular, in a connected vehicle, when the towed vehicle is in a straight traveling state or a state close thereto, the vehicle behavior can be improved even if the towed vehicle is turning. In this stabilization control, the driving force control (engine torque control) is automatically and quickly released.
[0006]
[Means for Solving the Problems]
In the first invention, the means for estimating the vehicle behavior from the vehicle state quantity, and the brake pressure on each wheel and the engine torque on the drive wheel so as to generate a yaw moment in the stabilization direction for reestablishing the abnormal vehicle behavior. Means for controlling the engine torque control to the driving wheel when the towed vehicle is in a straight traveling state or a state close to it even when the towed vehicle is turning, and the engine torque according to the driver's accelerator operation is And a means for enabling transmission to the device.
[0007]
In the second invention, the means for estimating the vehicle behavior from the vehicle state quantity, and the brake pressure on each wheel and the engine torque on the drive wheel so as to generate a yaw moment in the stabilization direction for reestablishing the abnormal vehicle behavior are obtained. The engine torque control to the driving wheel is canceled when the yaw rate value of the towing vehicle of the connected vehicle is equal to or less than the first specified value, and the engine torque according to the driver's accelerator operation can be transmitted to the driving wheel. And means for releasing the brake pressure control for each wheel when the yaw rate value of the tow vehicle is equal to or smaller than a second specified value smaller than the first specified value.
[0008]
【The invention's effect】
In the first aspect of the invention, when the tow vehicle of the connected vehicle is in a straight traveling state or a state close thereto, the engine torque control for the drive wheels is released, and the engine torque according to the driver's accelerator operation can be transmitted to the drive wheels. In addition, abnormal behavior (jack knife, trailer swing, etc.) of the towed vehicle can be prevented by the driving force of the towed vehicle. In this case, interference between the engine torque control that stabilizes the vehicle behavior and the driver's accelerator operation can be avoided. In addition, during the stabilization control of the vehicle behavior, the driver can perform the accelerator control only when the vehicle is in a straight traveling state or a state close thereto, so correction that gradually changes the target value as the control is switched is also possible. This is not necessary, and the configuration of the control system is simplified, which is advantageous in terms of cost.
[0009]
In the second aspect of the invention, when the yaw rate value of the vehicle is less than or equal to the first specified value, the engine torque control for the drive wheels is released, and when the yaw rate value is less than or equal to the second specified value, the brake pressure control to each wheel is performed. Is released. Therefore, by setting the first specified value as a criterion for determining whether the vehicle is in a straight traveling state or a state close thereto, the same operational effects as those of the first invention can be obtained. As the vehicle yaw rate value, one used for stabilization control of the vehicle behavior as one of the vehicle state quantities can be used as it is.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is an overall schematic diagram relating to a vehicle behavior stabilization system applied to a tractor of a connected vehicle. Reference numeral 3 denotes an engine, and an output shaft of the engine is connected to driving wheels via a power transmission mechanism. The engine 3 controls the fuel supply amount in response to a request from the control unit 1 to be described later, in addition to means for controlling the fuel supply amount (accelerator linkage, etc.) according to the accelerator operation amount (pedal pedal angle) of the driver. Actuators (not shown). Reference numerals 20 to 23 denote brake chambers for generating a braking force on each wheel, and the brake pressure to these chambers 20 to 23 is controlled by a brake valve (not shown) linked to a brake pedal in the driver's cab. It is controlled according to the tread angle. Further, a valve mechanism (not shown) for controlling the brake pressure of the brake chambers 20 to 23 is interposed in a circuit that does not pass through the brake valve.
[0011]
A control unit 1 is provided as means for controlling the brake pressure to each wheel and the engine torque to the drive wheel based on the vehicle state quantity. The vehicle state quantity is calculated based on detected values such as the rotational speed (wheel speed) of each wheel, the vehicle body lateral acceleration, and the yaw rate. 10-13 are wheel speed sensors, 4 is a lateral acceleration sensor, and 5 is a yaw rate sensor.
[0012]
In the control unit 1, when an abnormal vehicle behavior is determined from the vehicle state quantity, various types based on the vehicle state quantity are generated so as to positively generate a yaw moment in the direction of reestablishing (stabilizing) the abnormal vehicle behavior. The target slip ratio for each wheel and the target engine torque for the drive wheel are set by performing the calculation process of the brake circuit valve mechanism (each of the brake circuits so that the slip ratio (measured value) of each wheel matches the target slip ratio. The engine actuator (engine torque) is controlled so that the accelerator disclosure (detected value) of the engine matches the target engine torque.
[0013]
In the control unit 1, in order to ensure the effectiveness of the operation for reshaping abnormal vehicle behavior (accelerator operation, etc.) by the driver, when the vehicle is in a straight traveling state or a state close thereto, driving in the stabilization control of the vehicle behavior is performed. A function for quickly canceling the engine torque control for the wheel is added. FIG. 2 is a block diagram of the release function, 32 is a means for controlling the brake pressure for each wheel, 31 is a means for controlling the engine torque for the driving wheel, 30 is a means for detecting the vehicle state quantity (various sensors) And a means 33 for detecting a straight traveling state of the vehicle (towing vehicle) or a state close thereto, and based on this detection signal, the control unit 1 During the stabilization control of the vehicle behavior, the engine torque control for the drive wheels is quickly released.
[0014]
FIG. 3 is a flowchart for explaining the stabilization control of the vehicle behavior, which is repeatedly executed every predetermined control cycle. In step 1, the estimated vehicle body speed value Vref is calculated based on the detection signals of the wheel speed sensors 10-13. In step 2, the detection signal (lateral acceleration value Gy) of the lateral acceleration sensor 4 is read. In step 3, the detection signal (yaw rate value yaw) of the yaw rate sensor 5 is read. In step 4, the vehicle behavior instability S = Gy / Vref−yaw is calculated from the estimated vehicle speed Vref, the lateral acceleration value Gy, and the yaw rate value yaw. The estimated vehicle speed Vref is obtained as an average value of the wheel speeds.
[0015]
In step 5, it is determined whether or not the control flag F = 1. As will be described later, when F = 1, the vehicle behavior stabilization control is being performed, and when F = 1, the vehicle behavior stabilization control is being stopped (released). F = 0 is set. In step 6, it is determined whether instability S of the vehicle behavior determination reference value S ₀ or less. When this determination is yes (| S | ≦ S ₀ ), the vehicle behavior jumps to END as the normal range, while when no (| S |> S ₀ ), the vehicle behavior is not in the normal range (abnormal As the vehicle behavior occurs), the process proceeds to step 6, and based on the lateral acceleration value Gy, the estimated vehicle body speed value Vref, the yaw rate value yaw, etc., the brake pressure control and drive wheels for each wheel are controlled so as to stabilize the abnormal vehicle behavior. The engine torque control (stabilization control of vehicle behavior) is started.
[0016]
In step 8, it is determined whether the yaw rate value yaw is equal to or less than a specified value A1. In step 9, it is determined whether the yaw rate value yaw is equal to or less than a specified value A2. The specified values A1 and A2 are determination reference values for a straight traveling state of the vehicle or a state close thereto, and are set to A1 <A2. When yaw ≦ A1 (Yes in step 8), the vehicle behavior stabilization control is stopped and the control flag F = 0 is set in step 10 and step 11. If A1 <yaw ≦ A2 (the determination in step 8 is no and the determination in step 9 is yes), in step 12, the engine torque control is canceled. If yaw> A2 (the determination in step 8 is no and the determination in step 9 is no), the control flag F is set to 1 in step 13.
[0017]
With such a configuration, when the vehicle is in a straight traveling state or a state close thereto (A1 <yaw ≦ A2), the engine torque control for the drive wheels is automatically released earlier than the brake pressure control for each wheel, and the driver The engine torque according to the accelerator operation can be transmitted to the drive wheels. Therefore, when the towing vehicle goes straight or close to it while the connected vehicle is turning, the driver's accelerator operation pulls the towed vehicle while turning to prevent abnormal behavior (such as a jack knife or trailer swing). You can also
[0018]
In this case, interference between the engine torque control that stabilizes the vehicle behavior and the driver's accelerator operation can be avoided. In addition, during the stabilization control of the vehicle behavior, the driver can perform the accelerator control only when the vehicle is in a straight traveling state or a state close thereto, so correction that gradually changes the target value as the control is switched is also possible. This is not necessary, and the configuration of the control system is simplified, which is advantageous in terms of cost. Further, since accelerator control by the driver is not permitted until the vehicle is in a straight traveling state or a state close thereto, safety against erroneous operation of the accelerator pedal can be ensured.
[0019]
In this embodiment, it is determined (detected) based on the yaw rate value yaw of the vehicle whether or not the vehicle is in a straight traveling state or a state close thereto, but is not limited to the yaw rate value yaw, and is used for stabilization control of the vehicle behavior. The vehicle behavior instability S or the lateral acceleration value Gy may be detected.
[Brief description of the drawings]
FIG. 1 is a schematic diagram of a system representing an embodiment of the present invention.
FIG. 2 is also a partial block configuration diagram.
FIG. 3 is a flowchart for explaining the control content in the same manner.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Control unit 3 Engine 4 Lateral acceleration sensor 5 Yaw rate sensor 10-15 Wheel speed sensor 20-23 Brake chamber 30 Vehicle state quantity detection means 31 Engine torque control means 32 Brake pressure control means 33 Vehicle straight running state (or a state close thereto) detection means

Claims (2)

Means for controlling the means for estimating the vehicle behavior from the vehicle state quantity, the engine torque to the brake pressure and the driving wheel for each wheel to generate a yaw moment in the stabilizing direction rebuild abnormal vehicle behavior, the Means for canceling engine torque control to drive wheels and transmitting engine torque according to driver's accelerator operation to drive wheels when towing vehicle is moving straight or close to it even when towing vehicle is turning And a vehicle behavior control device for a connected vehicle . Means for controlling the means for estimating the vehicle behavior from the vehicle state quantity, the engine torque to the brake pressure and the driving wheel for each wheel to generate a yaw moment in the stabilizing direction rebuild abnormal vehicle behavior, coupled means for engine torque yaw rate value of the towing vehicle in accordance with the first predetermined value following release was driver's accelerator operation of the engine torque control to the drive wheels when the vehicle is to be transmitted to the drive wheels, like traction A vehicle behavior control device for a connected vehicle , comprising: means for releasing brake pressure control to each wheel when the yaw rate value of the vehicle is equal to or less than a second specified value that is smaller than the first specified value; .

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