US Patent 9751558 Handwheel obstruction detection and inertia compensation

A vehicle steering system includes a first sensor sensing a pinion angle of a handwheel and a second sensor sensing a torsion bar windup angle. An autonomous steering module generates a steering command having an input torque signal. A steering angle controller is configured to determine a filtered handwheel acceleration based on the pinion angle and the windup angle. The steering angle controller also determines an offset torque based on the filtered handwheel acceleration. Further, the steering angle controller applies the offset torque to the input torque signal to define a refined torque signal that compensates for inertia and off-center mass of the handwheel.