Vehicle behavior control device

• US 20030125864A1
• Filed: 12/12/2002
• Published: 07/03/2003
• Est. Priority Date: 12/12/2001
• Status: Active Grant

• Current Assignee: Advics Company Limited (Aisin Corp.)
• Original Assignee: Aisin Seiki Co., Ltd. (Aisin Corp.)
• Inventors: Monzaki, Shiro, Banno, Masaki
• Granted Patent: US 6,691,017 B2
• Time in Patent Office: Days
• US Class Current: 701/84
• CPC Class Codes: B60K 28/16 responsive to, or preventing, skidding of wheels brake control systems for vehicle drive stability B60T8/1755; arrangements responsive to a speed condition for adjusting wheel braking force B60T8/32; control of vehicle driving stability otherwise than by controlling the propulsion unit only B60W30/02; preventing wheel slippage by reducing power in rail vehicles B61C15/00
• CPC Class Codes: B60T 2201/16 Curve braking control, e.g. turn control within ABS control algorithm
• CPC Class Codes: B60T 2230/02 Side slip angle, attitude angle, floating angle, drift angle
• CPC Class Codes: B60T 8/175 Brake regulation specially adapted to prevent excessive wheel spin during vehicle acceleration, e.g. for traction control safety devices for propulsion unit control responsive to, or preventing, skidding of wheels B60K28/16
• CPC Class Codes: B60T 8/1755 Brake regulation specially adapted to control the stability of the vehicle, e.g. taking into account yaw rate or transverse acceleration in a curve road vehicle drive control systems for control of driving stability otherwise than by controlling a particular sub-unit B60W30/02
• CPC Class Codes: B60W 10/06 including control of combustion engines
• CPC Class Codes: B60W 10/184 with wheel brakes
• CPC Class Codes: B60W 2520/105 Longitudinal acceleration
• CPC Class Codes: B60W 2520/125 Lateral acceleration
• CPC Class Codes: B60W 2520/14 Yaw
• CPC Class Codes: B60W 2520/20 Sideslip angle
• CPC Class Codes: B60W 2520/26 Wheel slip
• CPC Class Codes: B60W 2552/40 Coefficient of friction
• CPC Class Codes: B60W 2710/0666 Engine torque
• CPC Class Codes: B60W 2710/0672 Torque change rate
• CPC Class Codes: B60W 2720/106 Longitudinal acceleration
• CPC Class Codes: B60W 30/18145 Cornering

Abstract

A vehicle behavior control device includes a turning limit state detecting device for detecting a turning limit state of a vehicle and an engine output control device for performing a torque-down control by decreasing an engine output when the turning limit state of the vehicle is detected. The engine output control device includes a longitudinal acceleration detecting device, a lateral acceleration detecting device, a road friction coefficient estimating device, a maximum longitudinal acceleration calculating device for calculating a maximum longitudinal acceleration from the estimated road friction coefficient by the road friction coefficient estimating device and the lateral acceleration detected by the lateral acceleration estimating device, and a margin calculating device for calculating a margin of the longitudinal acceleration of the vehicle as a deviation between the maximum longitudinal acceleration calculated by the maximum longitudinal acceleration calculating device and the longitudinal acceleration detected by the longitudinal acceleration detecting device.

Claims

1. A vehicle behavior control device comprising:

a turning limit state detecting means for detecting a turning limit state of a vehicle; and

an engine output control means for performing a torque-down control by decreasing an engine output when the turning limit state of the vehicle is detected, the engine output control means including a longitudinal acceleration detecting means for detecting a longitudinal acceleration in a substantially longitudinal direction of the vehicle, a lateral acceleration detecting means for detecting a lateral acceleration in a substantially lateral direction of the vehicle, a road friction coefficient estimating means for estimating a road friction coefficient, a maximum longitudinal acceleration calculating means for calculating a maximum longitudinal acceleration as a maximum value of the longitudinal acceleration being generated from the estimated road friction coefficient by the road friction coefficient estimating means and the lateral acceleration detected by the lateral acceleration estimating means, and a margin calculating means for calculating a margin of the longitudinal acceleration of the vehicle as a deviation between the maximum longitudinal acceleration calculated by the maximum longitudinal acceleration calculating means and the longitudinal acceleration detected by the longitudinal acceleration detecting means;

wherein a gradient of an engine output increase is controlled in response to the margin of the longitudinal acceleration of the vehicle calculated by the margin calculating means at a recovery stage of the engine output for reducing the engine output decrease amount during the torque-down control.

2. A vehicle behavior control device according to claim 1, wherein;

the maximum longitudinal acceleration calculating means calculates the maximum longitudinal acceleration by evaluating a square root of a value calculated by subtracting a square of the lateral acceleration value from a square of the estimated road friction coefficient.

3. A vehicle behavior control device according to claim 1, wherein:

the engine output control means further includes a torque-down amount detecting means for detecting a torque-down amount based on a spin state amount, a torque-down amount detecting means for detecting a torque-down amount based on a drift-out state amount, a comparison means for comparing the torque-down amounts based on the spin state amount and the drift-out state amount for determining whichever a larger amount as a reference value of a torque-down control amount, a torque-down control amount calculating means for calculating a torque-down control amount by using a torque-down amount of one cycle before and the reference value of the torque-down control amount, an engine output detecting means for detecting an engine output based on an engine speed and a main throttle opening angle, a target torque calculating means for calculating a target torque by using the torque-down control amount and the engine output, a target opening angle of a sub-throttle detecting means for detecting a target opening angle of the sub-throttle based on the engine speed and the target torque, wherein the engine output is increased or decreased so that the opening angle of the sub-throttle reaches substantially equal to the target opening angle thereof.

4. A vehicle behavior control device according to claim 1, wherein:

the turning limit state detecting means includes a side slip acceleration detecting means for detecting a slide slip acceleration of the vehicle as a deviation of the lateral acceleration, a vehicle body slip angle detecting means for detecting a vehicle body slip angle based on a side slip velocity and a longitudinal speed of the vehicle, a spin amount detecting means for detecting a spin amount of the vehicle based on the vehicle body slip angle and the side slip acceleration, a spin state amount detecting means for detecting a turning direction of the vehicle, a reference yaw rate calculating means for calculating a reference yaw rate by using a target yaw rate being calculated at the same time, a drift-out amount detecting means for detecting a drift-out amount of the vehicle based on the reference yaw rate and a yaw rate, a drift-out state amount detecting means for detecting a turning direction of the vehicle, a target slip ratio of a turning front outside wheel detecting means for detecting a target slip ratio of the turning front outside wheel based on the spin state amount, a target slip ratio of a total vehicle detecting means for detecting a target slip ratio of the total vehicle based on the drift-out state amount, a target slip ratio calculating means for calculating a target slip ratio of each wheel by using detected results by the target slip ratio of the turning front outside wheel detecting means and the target slip ratio of the total vehicle detecting means, a final target slip ratio calculating means for calculating a final target slip ratio of each wheel based on a determination of a turning direction of the vehicle, a final target slip ratio determining means for determining whether the final target slip ratio is 0 or not, a target wheel speed calculating means for calculating a target wheel speed of each wheel by using a reference wheel speed and the final target slip ratio of each wheel, a target slip amount calculating means for calculating a target slip amount of each wheel by using the target wheel speed of each wheel, a wheel acceleration of each wheel and the longitudinal acceleration, and a duty ratio detecting means for detecting the duty ratio of each wheel.