Abstract: A side-slip velocity estimation module for a vehicle stability enhancement control system includes a side-slip acceleration estimation module that estimates a side-slip acceleration of a vehicle. A multiple-order integrator integrates the side-slip acceleration to generate an estimated side-slip velocity of the vehicle. A reset logic module clears an output of the multiple-order integrator when the vehicle experiences a straight-driving condition, when a speed of the vehicle is less than a predetermined speed, and/or when a sensor bias condition occurs. The multiple-order integrator includes at least two accumulators and at least two feedback loops. The estimated side-slip velocity is a weighted sum of outputs of at least one of the at least two accumulators. A sum of the at least two feedback loops offsets the estimated side-slip acceleration.

Abstract: An active front-wheel vehicle steering control system that employs open-loop control that includes an adaptive compensation sub-system that compensate for changes in vehicle dynamic parameters. The control system includes a dynamic parameter estimation sub-system that provides an estimated understeer coefficient based on a front-wheel steering angle signal, a vehicle lateral acceleration signal, a vehicle yaw rate signal and a vehicle speed signal. An open-loop control sub-system generates a steering angle control signal for controlling steering of the front wheels using a combination of a nominal open-loop steering angle control signal and a corrected open-loop steering angle control signal that is based on a real-time estimated understeer coefficient.

Abstract: An active front-wheel vehicle steering control system that employs closed-loop control includes an adaptive compensation sub-system that compensates for changes in vehicle dynamic parameters. The control system includes a dynamic parameter estimation sub-system that provides an estimated front cornering compliance and rear cornering compliance based on a steering wheel angle signal, a vehicle lateral acceleration signal, a vehicle yaw rate signal and a vehicle speed signal. The closed-loop control includes active gain for each of vehicle yaw rate, yaw acceleration, side-slip and side-slip rate, all based on the vehicle speed and vehicle dynamic parameter changes for use in generating a steering angle control signal to the front wheels of the vehicle.

Abstract: A system and method for detecting vehicle wheel lift. The system includes wheel speed sensors for measuring the speed of each wheel of the vehicle, and suspension sensors for measuring the position of the vehicle suspension at each wheel of the vehicle. A controller determines whether any of the wheels are off the ground by using a kinematic relationship that uses the wheel speed signals and independently determines whether any of the wheels are off the ground by using damper spring displacement from the suspension sensors.

Abstract: A system and method for providing a vehicle roll stability indicator that estimates the propensity for vehicle rollover. The system determines vehicle kinematics from vehicle sensors, such as roll rate, yaw rate, lateral acceleration, vehicle speed, etc. From these kinematic values, the system estimates a roll angle of the vehicle and a bank angle of the vehicle. From the estimated bank angle, the system provides a corrected roll angle. From the corrected roll angle, the system determines a roll energy of the vehicle and a roll energy rate of the vehicle. From the roll energy and the roll energy rate, the system calculates a roll stability indicator that defines the potential that the vehicle will tip-up or roll over. From the roll stability indicator, vehicle stability control systems can take suitable action.

Abstract: A system and method for providing a vehicle roll stability indicator that dynamically estimates the probability for vehicle rollover. The system determines vehicle kinematics from various vehicle sensors. From these kinematic values, the system estimates a roll angle of the vehicle and a bank angle of the vehicle. The estimated bank angle is used to correct the roll angle. The system determines a roll energy of the vehicle and a roll energy rate of the vehicle from the corrected roll angle. The system also calculates a tire lateral load transfer of the relative forces on the vehicle tires, and the duration that any of the tires have been off of the ground. From the roll energy, the roll energy rate, the tire lateral load transfer and the wheel airborne duration, the system calculates the roll stability indicator.

Abstract: A system and method for estimating vehicle side-slip velocity that includes measuring the lateral acceleration of the vehicle, measuring the yaw rate of the vehicle, measuring the longitudinal speed of the vehicle and measuring the steering angle of the vehicle. The measured longitudinal speed is corrected to provide a true longitudinal speed using a filter factor based on the vehicle-dependent parameters and a steering angle. A constant is defined based on the measured longitudinal speed and a function is defined based on the combination of the vehicle-dependent parameters and the lateral acceleration. Side-slip acceleration is calculated using the measured lateral acceleration, the true longitudinal speed, the yaw rate, the constant and the function.

Abstract: An active rear-wheel vehicle steering control system that employs both open-loop and closed-loop control, where the open-loop and closed-loop control include adaptive compensation sub-systems that compensate for changes in vehicle dynamic parameters. The control system includes a dynamic parameter estimation sub-system that provides an estimated front-wheel cornering compliance and rear-wheel cornering compliance based on a front-wheel steering angle signal, a rear-wheel steering angle signal, a vehicle lateral acceleration signal, a vehicle yaw rate signal and a vehicle speed signal. The closed-loop control includes active gain for each of vehicle yaw rate, vehicle yaw rate acceleration, side-slip velocity and side-slip velocity rate, all based on the vehicle speed and vehicle dynamic parameter changes.

Abstract: A control system that employs closed-loop control for providing active vehicle rear-wheel steering, where the control system receives longitudinal wheel slip inputs to improve the vehicle directional stability. The longitudinal wheel slip inputs can be from one or more of wheel speed, traction control on and automatic braking system on. The control system includes an open-loop controller for generating an open-loop steering control signal, a yaw rate feedback controller for generating a yaw rate feedback signal, and a side-slip rate controller for generating a side-slip rate feedback signal. The open-loop steering control signal, the yaw rate feedback signal and the side-slip rate feedback signal are combined to generate the steering control signal to steer the vehicle rear wheels.

Abstract: An active front steering (AFS) system that provides hand-wheel damping. The AFS system includes a damping control sub-system that determines a hand-wheel angular velocity based on the rate of change of a hand-wheel angle signal. The damping control sub-system determines the damping control signal by multiplying the angular velocity of the hand-wheel angle signal with a control gain. The damping control signal is added to a steering signal from a variable gear ratio control sub-system to generate a steering command signal. The damping control sub-system sets to the damping control signal to zero if a signal from a vehicle stability enhancement sub-system is activated.

Abstract: An active rear-wheel vehicle steering control system that employs both open-loop and closed-loop control, where the open-loop and closed-loop control include adaptive compensation sub-systems that compensate for changes in vehicle dynamic parameters. The control system includes a dynamic parameter estimation sub-system that provides an estimated front-wheel cornering compliance and rear-wheel cornering compliance based on a front-wheel steering angle signal, a rear-wheel steering angle signal, a vehicle lateral acceleration signal, a vehicle yaw rate signal and a vehicle speed signal. The closed-loop control includes active gain for each of vehicle yaw rate, vehicle yaw rate acceleration, side-slip velocity and side-slip velocity rate, all based on the vehicle speed and vehicle dynamic parameter changes.

Abstract: A side-slip velocity estimation module for a vehicle stability enhancement control system includes a side-slip acceleration estimation module that estimates a side-slip acceleration of a vehicle. A multiple-order integrator integrates the side-slip acceleration to generate an estimated side-slip velocity of the vehicle. A reset logic module clears an output of the multiple-order integrator when the vehicle experiences a straight-driving condition, when a speed of the vehicle is less than a predetermined speed, and/or when a sensor bias condition occurs. The multiple-order integrator includes at least two accumulators and at least two feedback loops. The estimated side-slip velocity is a weighted sum of outputs of at least one of the at least two accumulators. A sum of the at least two feedback loops offsets the estimated side-slip acceleration.

Abstract: A control system that employs closed-loop control for providing active vehicle rear-wheel steering, where the control system receives longitudinal wheel slip inputs to improve the vehicle directional stability. The longitudinal wheel slip inputs can be from one or more of wheel speed, traction control on and automatic braking system on. The control system includes an open-loop controller for generating an open-loop steering control signal, a yaw rate feedback controller for generating a yaw rate feedback signal, and a side-slip rate controller for generating a side-slip rate feedback signal. The open-loop steering control signal, the yaw rate feedback signal and the side-slip rate feedback signal are combined to generate the steering control signal to steer the vehicle rear wheels.

Abstract: A vehicle stability enhancement system for a vehicle having at least one vehicle subsystem includes at least one sensor for sensing at least one vehicle parameter, at least one vehicle control system for adjusting the at least one vehicle subsystem wherein the at least one vehicle control system includes a rear wheel steering control system, at least one memory including at least one set of gain factors, and a controller responsive to the at least one sensor and the at least one set of gain factors for controlling the at least one vehicle control system.

Abstract: A side-slip velocity estimation module for a vehicle stability enhancement control system includes a side-slip acceleration estimation module that determines an estimated side-slip acceleration of a vehicle. A limited-frequency integrator integrates the estimated side-slip acceleration to determine an estimated side-slip velocity of the vehicle. A reset logic module clears an output of the limited-frequency integrator when a first condition occurs. The first condition is one of a straight-driving condition, a speed condition, and a sensor bias condition. The estimated side-slip velocity is compared to a desired side-slip velocity to produce a side-slip control signal. The side-slip control signal is combined with a yaw rate control signal to produce an actuator control signal. The actuator control signal is received by one of at least one brake actuator and a rear-wheel steering actuator to create a yaw moment to correct a dynamic behavior of the vehicle.

Abstract: A side-slip velocity estimation module for a vehicle stability enhancement control system includes a side-slip acceleration estimation module that determines an estimated side-slip acceleration of a vehicle. A limited-frequency integrator integrates the estimated side-slip acceleration to determine an estimated side-slip velocity of the vehicle. The limited-frequency integrator includes a feedback loop which incorporates a cutoff frequency for the integrator.

Abstract: A vehicle stability enhancement system for a vehicle having a vehicle subsystem includes a sensor for sensing a vehicle parameter, a vehicle control system for adjusting the vehicle subsystem, a memory having a register that includes a bank angle compensation control command, and a controller responsive to the sensor and the memory for controlling the vehicle control system.

Abstract: A side-slip velocity estimation module for a vehicle stability enhancement control system includes a side-slip acceleration estimation module that determines an estimated side-slip acceleration of a vehicle. A limited-frequency integrator integrates the estimated side-slip acceleration to determine an estimated side-slip velocity of the vehicle. A reset logic module clears an output of the limited-frequency integrator when a first condition occurs. The first condition is one of a straight-driving condition, a speed condition, and a sensor bias condition. The estimated side-slip velocity is compared to a desired side-slip velocity to produce a side-slip control signal. The side-slip control signal is combined with a yaw rate control signal to produce an actuator control signal. The actuator control signal is received by one of at least one brake actuator and a rear-wheel steering actuator to create a yaw moment to correct a dynamic behavior of the vehicle.

Abstract: A vehicle stability enhancement system for a vehicle having at least one vehicle subsystem includes at least one sensor for sensing at least one vehicle parameter, at least one vehicle control system for adjusting the at least one vehicle subsystem wherein the at least one vehicle control system includes a rear wheel steering control system, at least one memory including at least one set of gain factors, and a controller responsive to the at least one sensor and the at least one set of gain factors for controlling the at least one vehicle control system.

Abstract: A vehicle stability enhancement system for a vehicle having a vehicle subsystem includes a sensor for sensing a vehicle parameter, a vehicle control system for adjusting the vehicle subsystem, a memory having a register that includes a bank angle compensation control command, and a controller responsive to the sensor and the memory for controlling the vehicle control system.