Abstract: An AFS control system that combines and weights yaw rate feedback and side-slip rate feedback to provide increased vehicle stability enhancement control. The AFS system includes a yaw rate sub-system that generates a desired yaw rate signal. The AFS system also includes a side-slip rate sub-system that generates a desired side-slip rate feedback signal. The AFS system further includes a side-slip rate feedback sub-system that generates a side-slip rate feedback signal. The AFS system also includes a yaw rate feedback sub-system that generates a yaw rate feedback signal. The yaw rate feedback signal and the side-slip rate feedback signal are integrated in a control integration sub-system that generates a stability enhancement control signal. The control integration sub-system determines whether the vehicle is in an oversteer or understeer condition, and weights the desired yaw rate feedback signal accordingly based on the vehicle condition.

Abstract: Methods and systems are provided for controlling vehicle moding in response to a variety of driving conditions. The system comprises an input device configured to receive first and second inputs, a vehicle subsystem, and a controller coupled to each of the vehicle subsystem and the input device. The vehicle subsystem is configured to produce a parameter related to the driving condition in the first mode. The controller is configured to determine the driving condition from the parameter, control the vehicle subsystem to operate in a first mode based on the first input, and control the vehicle subsystem to operate in a second mode in response to one of the driving condition and the second input.

Abstract: A method and apparatus for providing integrated chassis control of a vehicle over the entire range of the vehicle dynamic state, including steady state and non-steady state steering conditions and linear and non-linear tire behavior, based on the general steer equation by using an estimated understeer and oversteer steering behavior indicator. The method and apparatus are particularly adapted to provide a yaw control apparatus and method. The steering behavior indicator may be calculated as a function of certain vehicle dynamic state inputs. A weighting factor for the calculation of the steering behavior indicator is determined as a function of certain vehicle dynamic state indication parameters.

Abstract: An AFS control system that combines and weights yaw rate feedback and side-slip rate feedback to provide increased vehicle stability enhancement control. The AFS system includes a yaw rate sub-system that generates a desired yaw rate signal. The AFS system also includes a side-slip rate sub-system that generates a desired side-slip rate feedback signal. The AFS system further includes a side-slip rate feedback sub-system that generates a side-slip rate feedback signal. The AFS system also includes a yaw rate feedback sub-system that generates a yaw rate feedback signal. The yaw rate feedback signal and the side-slip rate feedback signal are integrated in a control integration sub-system that generates a stability enhancement control signal. The control integration sub-system determines whether the vehicle is in an oversteer or understeer condition, and weights the desired yaw rate feedback signal accordingly based on the vehicle condition.

Abstract: A vehicle comprises a semi-active suspension including controllably adjustable suspension dampers. Open loop and closed loop damper commands are determined for each damper and, depending upon turning direction and damper motion, each damper is controlled with one of the open loop and closed loop damper commands.

Abstract: A vehicle includes a plurality of sub-systems and corresponding controllers for effecting normal control thereover. The vehicle further includes a vehicle dynamics controller for providing high-priority sub-system commands for sub-system control to effect vehicle dynamics enhancements. The vehicle dynamics controller includes a plurality of independently decomposable and recomposable software components or layers and accessible inter-layer bus structure.

Abstract: An active front wheel steering control system for a vehicle that includes a first control sub-system that provides AFS oversteer control to control the angle of the front wheels during an oversteer condition, and a second control sub-system that provides AFS understeer control to control the angle of the front wheels during an understeer condition. A controller monitors a first parameter as an oversteer flag associated with the first control sub-system and a second parameter as an understeer flag associated with the second control sub-system.

Abstract: A method and apparatus for providing integrated chassis control of a vehicle over the entire range of the vehicle dynamic state, including steady state and non-steady state steering conditions and linear and non-linear tire behavior, based on the general steer equation by using an estimated understeer and oversteer steering behavior indicator. The method and apparatus are particularly adapted to provide a yaw control apparatus and method. The steering behavior indicator may be calculated as a function of certain vehicle dynamic state inputs. A weighting factor for the calculation of the steering behavior indicator is determined as a function of certain vehicle dynamic state indication parameters.

Abstract: An integrated vehicle control system includes a first control system having a maximum authority to selectively operate a first vehicle sub-system and a second control system to selectively operate a second vehicle sub-system. A controller is adapted to monitor a first parameter associated with the first vehicle sub-system and a second parameter associated with the second vehicle sub-system. The controller is operable to control the first and second parameters by selectively invoking operation of the second control system when the first control system exceeds the maximum authority and the second parameter exceeds an upper threshold.

Abstract: A brake system control for use in a vehicle with four wheels comprising the steps of: determining a desired yaw rate (454); determining a yaw torque command responsive to the desired yaw rate (806); if the vehicle is in an anti-lock braking mode during driver commanded braking, applying the yaw torque command to only one of the four wheels to release brake pressure in said one of the four wheels (258-266, 274, 278, 280, 410-418); if the vehicle is in a positive acceleration traction control mode during driver commanded acceleration, applying the yaw torque command to only one of the four wheels to apply brake pressure in said one of the four wheels (258-266, 288-292, 410-418); and if the vehicle is not in the anti-lock braking mode or in the positive acceleration traction control mode, then: (i) determining whether a vehicle brake pedal is depressed (370); (ii) if the vehicle brake pedal is depressed, applying brake force to the vehicle wheels responsive to the depression of the brake pedal (374, 412, 418), w

Abstract: The onset of an excessive slip condition in a slip controller is determined so that it is adaptable to the actual drive torque conditions between the driven wheel and the road surface so as to achieve the desired acceleration or braking characteristics for all vehicle driving conditions including while the vehicle is traveling on a curved road surface. At low vehicle speeds, slip control is enabled when the value of a predetermined function of the difference in speeds of the driven and undriven wheels exceeds a threshold that is a function of the vehicle turn radius and at high vehicle speeds when the value of a predetermined function of a wheel slip ratio exceeds the threshold that is a function of the vehicle turn radius. The vehicle speed below which slip control is enabled based on a wheel speed function and above which traction control is enabled based on the wheel slip function increases with an increasing vehicle steering angle.

Abstract: A wheel slip control system for the left and right wheels common to an axle of a vehicle establishes a desired turning radius by controlling the wheel slip limit so as to establish the outer to inner wheel speed ratio .omega..sub.o /.omega..sub.i to a desired value (R.sub.d +d)/(R.sub.d -d) where Rd is the desired turning radius and 2d is the distance between the wheels. The desired steering radius is based upon the operator steering input and a desired understeer value.

Abstract: An apparatus provides improved vehicle handling during turning maneuvers by providing control of vehicle understeer. The understeer control includes determining a desired turning radius for the vehicle, a corresponding ideal outer to inner wheel speed ratio. A closed loop torque command is determined in proportion to the difference between the ideal wheel speed ratio and the actual wheel speed ratio. The closed loop torque command is used in conjunction with an open loop torque command responsive to operator power demand to provide wheel speed control in a manner to maintain the desired vehicle understeer characteristics.

Abstract: A control method for four wheel drive vehicles in which the front and rear wheels are not mechanically linked controls the drive torque to the vehicle wheels in proportion to vehicle loading and road surface friction coefficients in response to front and rear wheel speeds and front and rear wheel accelerations thereby reducing wheel spin.

Abstract: A vehicle acceleration wheel slip control system monitors wheel slip and when a wheel slip condition becomes excessive as wheel slip increases during vehicle acceleration, engine torque output is initially reduced in accord with the rate of change in wheel slip. This derivative adjustment produces a significant correction to the engine torque output before the slip condition becomes very large. Thereafter, when the slip condition represents recovery from the excessive slip condition, the engine torque output is controlled in accord with the error in wheel slip from a desired value. This proportional adjustment maintains a desired slip value while maintaining stable acceleration slip control.

Abstract: A vehicle traction control system includes both driven wheel brake control and engine torque output control for limiting acceleration wheel slip. A boundary condition is identified where engine torque output control alone can be used without braking to regulate the acceleration wheel slip to any desired value. When the traction control system determines that the boundary condition is not exceeded such that engine torque output control alone is capable of preventing an excessive slip condition, only engine torque is controlled to limit wheel slip. However, when the system determines the boundary condition is such that engine torque output control alone will not prevent an excessive slip condition, the brakes of the slipping wheel is then additionally controlled to limit acceleration wheel spin.

Abstract: A method for preventing excessive spin to the driven wheels of a vehicle by determining the value of slip where the wheel/road tractive force is maximized for the particular coefficient friction road operating surface. The reaction torque, as translated through the differential, is considered and wheel control is therefore optimized based upon individual wheel acceleration characteristics and cross-differential torque transfer.