Infrastructure and Method to Estimate Steering System Friction and Maintain System Health

摘要

The presented invention provides an accurate estimate of the friction torque in a steering system 1 equipped with an electric power steering (EPS) assist motor 2. The steering column has an encoder 3, tachometer, and input torque sensor 4. The EPS motor also has a torque sensor 2. Vehicle dynamic signals yaw rate, lateral acceleration, and vehicle speed are read from the CAN line 5. A steering resistive forces estimator 5 calculates the friction torque T_(friction), road torque T_(road), inertial torque T_(inertial) and viscous torque T_(viscous), The friction torque is sent to by a telematics platform 7 to an off-board server 8 where the remaining useful life is estimated. This estimate is sent back to the vehicle by the telematics platform 7 and an in-vehicle alert 9 is issued when the friction grows too high. The friction torque estimate is also used by a fault-tolerant controller 10 to extend the life of the EPS motor 2.