Other

Gm Global Technolgoy Operations, Inc.

Eugene A Rodden

Scott P Sherman

Paul A Grougan

Yuen-Kwok Chin

Weiwen Deng

Steven D Klein

William Chin-Woei Lin

Scott M Wendling

Roderick L Lemmer

A method directed to improving the stability of a motor vehicle having front and rear steering capabilities includes determining a coefficient of friction of the road surface with which the motor vehicle is engaged and adjusting a phase gain function of a rear steering mechanism to compensate for the steerability of the motor vehicle over the road surface. A system for improving the stability of a motor vehicle having front and rear steering capabilities includes a control unit, a front steering mechanism in informational communication with the control unit, and a rear steering mechanism in informational communication with the control unit. The rear steering mechanism is responsive through the control unit to road conditions of the road surface.

Four wheel steering compensation for low coefficient of friction surface

A method is disclosed for controlling the rear wheel angle in a four-wheel steering vehicle such as a pickup truck. The front wheels are steered using the conventional operator handwheel linked to the front wheels. The rear wheels are actuated with a reversible electric motor and the rear wheel angle controlled using a computer with inputs of vehicle velocity, operator handwheel position and correlated front wheel angle, and handwheel turning rate. Control of rear wheel angle starts with a correlation of ratios of rear wheel angle to front wheel angle, R/F, vs. vehicle velocity suitable, determined under steady state front steering angle and velocity conditions, to maximize the contribution of the rear wheels while avoiding side-slip of the vehicle. It is found that driver steering feel and vehicle maneuverability is improved by imposing a minimum front wheel angle requirement before rear wheel steering is permitted and by modifying the current value of R/F with gain factors base d on the hand wheel angle and rate of motion.

Rear wheel steering control

Growing community of inventors

Gilbert, AZ, United States of America

Eugene A Rodden