Data processing: vehicles – navigation – and relative location – Vehicle control – guidance – operation – or indication – Indication or control of braking – acceleration – or deceleration
Reexamination Certificate
1999-03-19
2001-02-06
Cuchlinski, Jr., William A. (Department: 3661)
Data processing: vehicles, navigation, and relative location
Vehicle control, guidance, operation, or indication
Indication or control of braking, acceleration, or deceleration
C701S071000, C701S072000, C303S140000, C303S146000, C303S147000, C303S148000
Reexamination Certificate
active
06185497
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Technical Field of the Invention
The present invention relates generally to a behavior control apparatus for vehicles which monitors the behavior of a vehicle body and automatically regulates the braking effort applied to each wheel to control the behavior of the vehicle body.
2. Background Art
Japanese Patent First Publication No. 9-226555 discloses an automatic brake control system for vehicles designed to control brake pressure (i.e., wheel cylinder pressure) applied to each wheel as a function of traveling conditions of the vehicle. This system monitors the lateral acceleration acting on the vehicle, the direction of a turn, and the brake pedal effort produced by a vehicle operator to determine a target wheel speed of a compliance one of outside wheels during turning based on the speed of a front one of inside wheels and the lateral acceleration when no brakes are applied and to determine a target wheel speed of a front one of inside wheels during turning based on the speed of a front one of the outside wheels and the lateral acceleration when the brakes are being applied and the braking force applied to the wheels according to one of the target wheel speeds. In brief, a control reference value used in controlling a speed difference between the outside and inside wheels during turning based on the lateral acceleration is switched between states of applying the brakes and applying no brakes, thereby bringing the rotation of the right and left wheels into a preselected condition, e.g., by adjusting the speeds of the right and left wheels to have the same slip ratio for stability of vehicle motion.
The above conventional system, however, does not estimate a vehicle condition in the automatic brake control and may encounter the problems that the automatic brake control causes the deterioration of vehicle behavior and/or the lack of braking force. Specifically, when the automatic brake control is carried out without taking a dynamic balance of the whole of a vehicle body into account in determining a target controlled state of each wheel, it may cause the dynamic balance of the vehicle body or vehicle behavior to be deteriorated.
SUMMARY OF THE INVENTION
It is therefore a principal object of the present invention to avoid the disadvantages of the prior art.
It is another object of the present invention to provide a vehicle behavior control apparatus which estimates the state of behavior of a vehicle body accurately to determine a target controlled wheel(s) and which applies suitable braking efforts to the wheels.
It is a further object of the invention to provide a vehicle behavior control apparatus which is capable of estimating the state of behavior of a vehicle body accurately to control a preselected actuator.
According to one aspect of the invention, there is provided a vehicle behavior control apparatus. The vehicle behavior control apparatus comprises (a) a wheel speed sensor measuring speeds of wheels; (b) a brake actuators producing braking efforts applied to wheels of a vehicle; (c) a lateral momentum determining circuit determining a lateral momentum of a vehicle body during traveling; (d) a vehicle state estimating circuit estimating a state of behavior of the vehicle body based on the speeds of the wheels measured by the wheel speed sensor and the lateral momentum determined by the lateral momentum determining circuit; (e) a target braking effort determining circuit determining a target braking effort to be produced by each of the brake actuators based on the state of behavior of the vehicle estimated by the vehicle state estimating circuit; and (f) a braking effort regulating means for regulating the braking efforts produced by the brake actuators so as to agree with the target braking efforts, respectively, to control behavior of the vehicle body.
In the preferred mode of the invention, the vehicle state estimating circuit includes a wheel state variable determining means for determining a wheel state variable based on a difference in speed between the right wheel and the left wheel and estimates the state of behavior of the vehicle body based on the wheel state variable.
The wheels of the vehicle consists of a pair of front right and left wheels and a pair of rear right and left wheels. The wheel state variable determining means determines a front wheel state variable based on a difference in speed between the front right and left wheels and a rear wheel state variable based on a difference in speed between the rear right and left wheels. The vehicle state variable determining circuit estimates the state of behavior of the vehicle body based on the front and rear wheel state variables.
The wheel state variable means may alternatively determine a first diagonal wheel state variable indicative of stability in a diagonal direction of the vehicle body from the front right wheel to the rear left wheel based on a difference in speed between the front right wheel and the rear left wheel and a second diagonal wheel state variable indicative of stability in a diagonal direction of the vehicle body from the front left wheel to the rear right wheel based on a difference in speed between the front left and rear right wheels. The wheel state determining means estimates the state of behavior of the vehicle body based on the first and second diagonal wheel state variables.
The vehicle state estimating circuit may estimate the state of behavior of the vehicle body based on a front state variable and a rear state variable. The front state variable indicates stability of a front portion of the vehicle body and is determined based on a difference between the lateral momentum and the front wheel state variable. The rear state variable indicates stability of a rear portion of the vehicle body and is determined based on a difference between the lateral momentum and the rear wheel state variable.
The vehicle state estimating circuit may alternatively estimate the state of behavior of the vehicle body based on a first state variable and a second state variable. The first state variable indicates stability of a first diagonal portion of the vehicle body and is determined based on a difference between the lateral momentum and the first diagonal wheel state variable. The second state variable indicates stability of a second diagonal portion of the vehicle body and is determined based on a difference between the lateral momentum and the second diagonal wheel state variable.
The vehicle state estimating circuit determines a first state parameter indicating instability of the whole of the vehicle body based on the sum of the front and rear state variables and uses the first state parameter in estimating the state of behavior of the vehicle body.
The vehicle state estimating circuit may alternatively determine the first state parameter based on the sum of the first and second state variables and uses the first state parameter in estimating the state of behavior of the vehicle body.
The vehicle state estimating circuit determines a second state parameter indicating a location of a portion of the vehicle body which is unstable in behavior of the vehicle body based on a difference between the front and rear state variables and uses the second state parameter in estimating the state of behavior of the vehicle body.
The vehicle state estimating circuit may alternatively determine the second state parameter based on a difference between the first and second state variables and use the second state parameter in estimating the state of behavior of the vehicle body.
The vehicle state estimating circuit determines which of the wheels whose road-tire adhesion reaches a limit based on a value of the second state parameter.
The vehicle state estimating circuit classifies the state of behavior of the vehicle body into a plurality of different states based on the first and second state parameters.
The vehicle state estimating circuit classifies the state of behavior of the vehicle body into the different states by comparing the first state parameter with the second state para
Katou Tomohiro
Nagata Tosirou
Onogi Nobuyoshi
Taniguchi Masahiko
Cuchlinski Jr. William A.
Denso Corporation
Mancho Ronnie
Pillsbury Madison & Sutro LLP
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