Delphi Technologies, Inc.

Gm Global Technolgoy Operations, Inc.

Delco Electronics Corporation

Scott E Weiss

Joel Edward Birsching

Sanket S Amberkar

William C Lin

Thomas Arthur Perry

John Robert Bradley

Steven D Klein

Andrzej M Pawlak

David W Graber

Dennis C Eckhardt

Scott M Wendling

Reeny T Sebastian

Maged Radamis

A power steering system for a vehicle includes a hydraulic system for controlling resistance of a steering wheel. A valve of the hydraulic system is connected to a coil which varies positioning of the valve. A method for controlling the resistance of the steering wheel includes turning the steerable wheels of the vehicle in response to rotation of the steering wheel. The angle of the steering wheel and the speed of the vehicle are sensed and inputted into a controller. A lateral acceleration is determined based on the sensed signals by the controller. A recommended current rate of the coil is determined based on the lateral acceleration. An adjustment to the recommended current rate of the coil is determined based upon the speed of the vehicle. The recommended current rate is also modified based upon the adjustment. The modified current rate of the coil is then applied to the coil to vary the stiffness of the valve, which in turn varies the resistance to turning the steerable wheels of the vehicle.

Electric preload for variable effort steering system

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. The method also includes the step of first disposing a torsion rod having a first stiffness between the pinion and spool shaft to resist rotation of the spool shaft relative to the pinion from the on-center orientation and resist movement of the valve from the open configuration to the closed configuration. The method also includes the step of second disposing a magnetic coupling having a variable second stiffness in parallel with the torsion rod to resist rotation of the spool shaft relative to the pinion from the on-center orientation and resist movement of the valve from the open configuration to the closed configuration. The first stiffness and the variable second stiffness cooperate to define an overall valve stiffness. The method also includes the step of varying the variable second stiffness generated by the magnetic coupling with an electric coil to vary the overall valve stiffness. The method also includes the step of maximizing the variable second stiffness generated by the magnetic coupling when the spool shaft and the pinion are on-center with respect to one another.

Disclosed is a method for aligning a position sensor in a vehicle with steerable wheels comprising obtaining an absolute position value responsive to a position signal from a handwheel position sensor, obtaining a relative position value responsive to an encoder signal count from a position encoder, and obtaining an index position value responsive to an index position signal. The method further includes receiving an alignment enable signal and determining a correction factor responsive to the relative position value and the index position value. The method for aligning a position sensor is responsive to at least one of the absolute position value, the relative position value, and the index position value under conditions determined from the status of the alignment enable signal. Also disclosed is a method for aligning a steerable wheel in a vehicle with electric power steering comprising obtaining an alignment correction corresponding to a computed correction of wheel position relative to the vehicle from an alignment apparatus, receiving an alignment enable signal, where the method of aligning is responsive to the alignment correction under conditions determined from the status of the alignment enable signal.

Four wheel steering alignment process

A rotary encoder capable of detecting angular rotation of a rotating shaft, and identifying its neutral position without the need for multiple encoder wheels. A magnetoresistive sensor is positioned adjacent the periphery of a single multipole magnet ring attached to a steering wheel shaft. The magnet ring comprises alternating N-pole and S-pole magnetic regions along its periphery, the surface of one of the regions containing a demagnetized portion. The sensor produces a sinusoidal signal as the shaft is rotated, responsive to the passage of the magnetic regions, with a period equal to the passage of two successive magnetic regions adjacent the sensor. The angular position of the shaft which aligns the demagnetized portion adjacent the sensor corresponds to the shaft's neutral position. Aligning of the demagnetized portion adjacent the sensor causes a voltage irregularity within the sensor's otherwise sinusoidal output signal, which is detected by a signal processing circuit.

Rotary encoder with neutral position

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Bay City, MI, United States of America

Scott E Weiss