What I know is that EPS has a torque sensor,vehicle speed and BLDC motor with Hall sensor. You can know rotor speed with Hall sensor, and if you put a Rsense in your control circuit (3-phase MOSFET bridge) you can do a torque control with 2 feedback ( rotor speed and current). You can use PID for damping control when for example you have a torque pulse input (kickback). I think the worst case is bump and brake. When the car speed increase, steering is more hard. Normaly, the driver do maximum of 5 Nm to Steering Wheel.
Sorry for my little english and I hope this information help you.