Variable road feedback device for steer-by-wire systems

A steer-by-wire system for a vehicle, the system comprising:

• a plurality of sensors for generating a plurality of input signals, comprising at least one column sensor for sensing changes in at least one of position and torque of a steering wheel and comprising a plurality of wheel sensors for sensing changes in at least one of position and torque of a plurality of steerable vehicle wheels;
• an electrical power steering motor coupled to a vehicle steering system for assisting a vehicle operator;
• and
• a housing containing:
• a magnetorheological fluid;
• a magnetic field generator adapted to produce a magnetic field within the magnetorheological fluid and vary a viscous resistance of the fluid;
• and
• a rotor rotatably mounted within the housing in contact with the magnetorheological fluid wherein the rotor includes a plurality of vanes fixedly attached to the rotor, the vanes being positioned and shaped to be sensitive and responsive to the viscous resistance of the magnetorheological fluid.

A method for generating a variable viscous resistance within a housing, which contains therein a magnetorheological fluid and a rotor, whereby a vehicle operator feels resistance while turning a steering wheel, the method comprising:

• sensing a plurality of input signals with a plurality of sensors;
• generating a variable magnetic field within the housing in accordance with the sensed plurality of input signals;
• varying a viscosity of the magnetorheological fluid in accordance with the generated magnetic field;
• and
• increasing resistance to rotation of the rotor through an interaction of a plurality of vanes fixedly attached to the rotor with the varied viscosity of the magnetorheological fluid to thereby provide feedback to the vehicle operator through the steering wheel.

A variable road feedback steer-by-wire system for a vehicle, the system comprising:

• a steering column;
• a plurality of sensors including one or more column sensors and one or more road wheel sensors, said column sensors being configured to generate first input signals indicative of changes in position and/or torque of said steering column, said road wheel sensors being configured to generate second input signals indicative of changes in position and/or torque of one or more steerable road wheels of said vehicle;
• a rotor secured to said steering column such that rotation of said steering column causes a corresponding rotation of said rotor;
• a housing disposed about said rotor, said housing containing a magnetorheological fluid such that said rotor is rotatable through said magnetorheological fluid;
• a magnetic field generator for selectively producing a magnetic field within said magnetorheological fluid based upon said first and second input signals, said magnetic field being sufficient to vary a viscosity of said magnetorheological fluid;
• and
• a plurality of vanes fixedly attached to the rotor, said plurality of vanes being positioned and shaped to be sensitive and responsive to said viscosity.