The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 24, 2018
Filed:
Jun. 09, 2015
GM Global Technology Operations Llc, Detroit, MI (US);
Ian Y. Hwa, West Bloomfield, MI (US);
GM Global Technology Operations LLC, Detroit, MI (US);
Abstract
A method for characterizing a stick-slip condition in a steering system includes transmitting a periodic steering control signal to a rotary actuator to cause rotation of a steering shaft, through a torsion bar and inertia wheel, over a range of steering angles, and applying an axial force to a rack to resist rack displacement from a centered position. A steering torque output value is measured via a torque transducer. A control action is executed when a measured difference between a maximum value of a steering torque required to initiate rack motion/torque breakaway and a minimum value of the steering torque after breakaway for start-up or subsequent steering reversal exceeds a calibrated threshold. A system includes the rotary actuator, steering system, torque transducer, torsion bar, inertia wheel, linear actuator(s) providing an axial force along the rack axis to resist rack displacement from a centered position, and controller programmed as noted above.