Patent ID: 11897551
Assignee: SENTIENT IP AB
Field: Transport (Mechanical engineering)
Classification: CPC B | IPC B

Claim 0:
1. A steering system comprising:
a steering assistance actuator with a torsion bar and a feedback torque actuator with a motor with an Electric Control Unit (ECU) for giving feedback to a driver, and
a steering wheel to which the driver applies a driver torque (TD),
wherein the steering assistance actuator comprises a torsion-bar torque sensor for sensing the torque in the torsion bar,
means for measuring a steering angle, and
the ECU of the motor of the feedback torque actuator comprises means for calculating the driver torque (TD) and means for calculating a target feedback torque actuator state, comprising a target feedback torque or a target steering angle, for controlling the feedback torque actuator such that the target feedback torque actuator state is reached,
the target feedback torque actuator state for the feedback torque actuator being a target steering feel torque compensated with the torque sensed in the torsion-bar torque sensor, and
the ECU is configured for measuring a current in the motor of the feedback torque actuator to provide current measurements, transforming the current to an estimated feedback torque by the use of a current-to-torque characteristics of the motor, calculating the driver torque by adding the sensed torsion-bar torque and the estimated feedback torque, calculating the target feedback torque actuator state from either said calculated driver torque or from said measured steering angle, and controlling the feedback torque actuator via a closed loop current control to achieve the target feedback torque actuator state.