Abstract: The invention provides a method for controlling valve stiffness in a power steering system. The method includes the step of engaging a pinion and a spool shaft with respect to one another for turning at least two wheels of a vehicle in response to rotation of a steering wheel from an on-center orientation. The method also includes the step of variably assisting movement of the pinion with a hydraulic power steering device having a valve movable between a closed configuration and an open configuration. The method also includes the step of moving the valve from the open configuration to the closed configuration in response to rotation of the spool shaft relative to the pinion from an on-center orientation to assist the pinion in rotation for turning the at least two wheels.

Abstract: The invention provides a method for controlling valve stiffness in a power steering system. The method includes the step of engaging a pinion and a spool shaft with respect to one another for turning at least two wheels of a vehicle in response to rotation of a steering wheel from an on-center orientation. The method also includes the step of variably assisting movement of the pinion with a hydraulic power steering device having a valve movable between a closed configuration and an open configuration. The method also includes the step of moving the valve from the open configuration to the closed configuration in response to rotation of the spool shaft relative to the pinion from an on-center orientation to assist the pinion in rotation for turning the at least two wheels.

Abstract: A steering system with reduced coupling between a position overlay unit and a torque overlay unit may include a remote valve assembly for controlling a hydraulic assist force or an electric motor for providing torque overlay and electric assist to a rack of a rack and pinion steering system. In one embodiment, the position overlay unit may provide the assist force and the torque overlay unit may provide a motor command signal to the motor of a differential positioned on a steering shaft. In another embodiment, the position overlay unit may provide the motor command signal and the torque overlay unit may provide the assist force. In either embodiment, the position overlay unit may include variable ratio gain that uses a position signal to output a variable ratio command.

Abstract: Disclosed herein is steer-by-wire control systems comprising: a road wheel unit responsive to a road wheel command signal including a road wheel position sensor and a road wheel force sensor. The steer-by-wire control system also includes a steering wheel unit responsive to a steering wheel torque command signal, including a steering wheel position sensor and a torque sensor. The steer-by-wire control system further includes a vehicle speed sensor, and a master control unit operatively connected to the vehicle speed sensor, the steering wheel unit, and the road wheel unit. The road wheel unit is also responsive to the road wheel force signal.

Abstract: A method for estimating the yaw rate of a vehicle. The method includes receiving at least one signal indicative of a vehicular lateral acceleration and receiving at least one signal indicative of a vehicular wheel velocity. A plurality of yaw rate estimation functions are provided. A first yaw rate estimation function of the plurality of yaw rate estimation functions is selected in response to at least one of the received signals. A first estimated yaw rate is estimated in accordance with the selected first yaw rate estimation function and at least two signals each indicative of a wheel velocity. If the first estimated yaw rate is not within a threshold value of an actual measured yaw rate, a second yaw rate estimation function is selected to obtain a second estimated yaw rate using a signal indicative of lateral acceleration for correlation with the actual measured yaw rate.

Abstract: Disclosed herein are two exemplary steer-by-wire control systems comprising: a road wheel unit responsive to a road wheel command signal including a road wheel position sensor and a road wheel sensor. The steer-by-wire control system also includes a steering wheel unit responsive to a steering wheel torque command signal, including a steering wheel position sensor and a torque sensor. The steer-by-wire control system further includes a vehicle speed sensor, and a master control unit operatively connected to the vehicle speed sensor, the steering wheel unit, and the road wheel unit. The road wheel unit is also responsive to the road wheel force signal and/or the steering wheel unit is also responsive to the steering wheel position signal.

Abstract: A method for estimating the yaw rate of a vehicle. The method includes receiving at least one signal indicative of a vehicular lateral acceleration and receiving at least one signal indicative of a vehicular wheel velocity. A plurality of yaw rate estimation functions are provided. A first yaw rate estimation function of the plurality of yaw rate estimation functions is selected in response to at least one of the received signals. A first estimated yaw rate is estimated in accordance with the selected first yaw rate estimation function and at least two signals each indicative of a wheel velocity. If the first estimated yaw rate is not within a threshold value of an actual measured yaw rate, a second yaw rate estimation function is selected to obtain a second estimated yaw rate using a signal indicative of lateral acceleration for correlation with the actual measured yaw rate.