Visteon Global Technolgoies, Inc.

Brian E Daugherty

Muqtada Husain

John Oynoian

Robert T Palmer

Yixin Yao

Kyi-Shin Shiah

Joseph Platz

John R Balint, Iii

A control system and method for a steer-by-wire system with the passive resistance torque is provided. The control system includes a controller configured to compensate for a passive resistance torque and to generate the required active torque using a three loop control structure: torque feedback loop, rate feedback loop, and steering wheel angle feedback loop. The torque feedback loop is based on an estimated steering torque signal calculated from a steering angle signal, a steering angle rate signal, and a motor current signal.

Control of a steering wheel system with passive resistance torque

The present invention comprises a steering system selectively operable in one of three modes: steer-by-wire, electronic power assist steering (EPAS), and manual steering. The steer-by-wire system includes a driver interface system (DIS), a road wheel actuator system (RWAS), and a controller for monitoring and implementing the preferred control strategy. The steering system of the present invention operates normally in a steer-by-wire mode. In each of the EPAS mode and manual mode, the controller causes a clutch mechanism to engage, thus creating a mechanical linkage between portions of the DIS and the RWAS. In the EPAS mode, one of the road wheel actuator or the reaction torque generator is available to assist in the steering operation. Alternatively, in the manual mode, both the DIS and the RWAS are deactivated and the vehicle is steerable through entirely mechanical means.

Motor vehicle steering system

A steering system selectively operable in one of six modes: steer-by-wire with rear steering, steer-by-wire without rear steering, electronic power assist steering (EPAS) with rear steering, electronic power steering (EPAS) without rear steering, mechanical backup manual steering with rear steering, and mechanical backup manual steering without rear steering. The steer-by-wire system includes a driver interface system (DIS), a front road wheel actuator system (FRWAS), a rear road wheel actuator system (RRWAS), and a controller for monitoring and implementing the preferred control strategy. The steering system operates normally in a steer-by-wire mode. In each of the EPAS mode and manual mode, the controller causes a clutch mechanism to engage, thus creating a mechanical linkage between the steerable member and the rack and pinion system while maintaining rear wheel assisted steering. In the EPAS mode, one of the front road wheel actuator or the reaction torque generator is available to assist in the steering operation along with rear wheel steering. Alternatively, in the manual mode, both the DIS and the FRWAS are deactivated and the vehicle is steerable through mechanical device along with the rear wheel assisted steering.

The present invention provides a system for generating an end of travel feedback to the driver of a vehicle where the vehicle includes a steer by wire system. The system includes a steering wheel, a steering shaft, a motor, and a brake. The steering wheel is configured to control the steer by wire system. The steering shaft is coupled to the steering wheel and rotates in conjunction with the steering wheel. To provide road feel resistance to the driver, the motor is coupled to the steering shaft. Further, the brake is coupled to a shaft of the motor and is adapted to provide mechanical resistance when the road wheel is at an end of travel position.

End of travel system and method for steer by wire systems

A steer-by-wire system for an automotive vehicle comprises a driver interface system that includes a steering wheel mounted on a steering column. A reaction torque generator is coupled to the steering column for applying a resistive torque in response to a steering command to create a steering feel. An electromechanical brake, such as a magnetorehological brake, is also coupled to the steering column. During operation, a controller receives an input signal indicative of road wheel response to a steering command and determines when the road wheels have reached a limit, such as by engaging mechanical stops mounted on the vehicle or prevented from movement by curb or other external obstacle. In response, the controller actuates the electromechanical device to prevent rotation of the steering wheel and thereby alert the driver that the road wheels have reached a limit.

Driver interface system for steer-by-wire system

The present invention comprises a steering system selectively operable in one of three modes: steer-by-wire, electronic power assist steering (EPAS), and manual steering. The steer-by-wire system includes a driver interface system (DIS), a road wheel actuator system (RWAS), and a controller for monitoring and implementing the preferred control strategy. The steering system of the present invention operates normally in a steer-by-wire mode. In each of the EPAS mode and manual mode, the controller causes a clutch mechanism to engage, thus creating a mechanical linkage between the steerable member and the rack and pinion system. In the EPAS mode, one of the road wheel actuator or the reaction torque generator is available to assist in the steering operation. Alternatively, in the manual mode, both the DIS and the RWAS are deactivated and the vehicle is steerable through entirely mechanical means.

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Ann Arbor, MI, United States of America

Brian E Daugherty