Gm Global Technolgoy Operations, Inc.

Willard A Hall

Chandra S Namuduri

Weiwen Deng

Yong Han Lee

Robert R Bolio

Thomas R Brown

Joseph J Gies, Iii

An active front steering system includes a motor controller configured to compute a position error from a commanded position value and an actual position value, and then enter one of two modes&#x2014;a commutation enable mode and a commutation freeze mode&#x2014;depending upon the value of this position error. The commutation freeze mode applies when the absolute value of the position error is less than a predetermined threshold, and involves sending a set of signals to the motor's phase inputs such that commutation of the motor is prevented and a substantially constant motor hold torque is produced. The commutation enable mode applies when the absolute value of the position error is greater than or equal to the predetermined threshold, and corresponds to normal commutating operating mode.

Methods and apparatus for an active front steering actuator

The invention describes a sensor mechanism for measuring hitch articulation angle. A configuration of the contact face between hitch ball and receiver eliminates the effect of the unwanted trailer motions, such as roll and pitch while accurately registering trailer yaw motion. Also, there is no yaw slippage at the contact that was a major problem during the successive acceleration and brake maneuvers. With the freely rotating ball and shaft, the angle is measured using an angle sensor, such as an optical encoder, potentiometer, or other means. For the case of a relative angle sensor, automatic zero angle calibration can be used to allow an absolute angle measurement.

Sensing mechanism for hitch articulation angle

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Dryden, MI, United States of America

Willard A Hall