Hands-off detection enhancement by means of a synthetic signal

A method for determining whether a driver of a vehicle is in contact with a steering wheel of the vehicle, comprising the steps of:

• determining a speed of a road wheel of the vehicle;
• generating a perturbation signal that causes vibration of the steering wheel, a frequency of the perturbation signal responsive to the speed of the road wheel of the vehicle;
• receiving a first steering signal from a first steering system sensor configured to provide an indication of at least one of a steering torque and a steering movement of a component of an electronic power steering system of the vehicle;
• and,
• generating a driver contact signal indicative of whether the driver of the vehicle is in contact with the steering wheel of the vehicle, a value of the driver contact signal dependent on characteristics of the first steering signal relating to the perturbation signal.

A system for determining whether a driver of a vehicle is in contact with a steering wheel of the vehicle, comprising:

• an electronic power steering system including
• a motor configured to cause movement of a road wheel of the vehicle responsive to movement of the steering wheel, and
• a first steering system sensor configured to provide an indication of at least one of a steering torque and a first steering movement of a first component of the electronic power steering system;
• and,
• a controller configured to
• generate a control signal configured to cause the motor to generate a perturbation signal that causes vibration of the steering wheel;
• receive a first steering signal from the first steering system sensor;
• mix the perturbation signal and the steering signal to produce a first heterodyne signal;
• and,
• generate a driver contact signal indicative of whether the driver of the vehicle is in contact with the steering wheel of the vehicle, a value of the driver contact signal dependent on characteristics of the first heterodyne signal relating to the perturbation signal.