Speed measurement for steering wheel rotation uses estimated resistance of power assisting motor derived from voltage and current measurements

摘要

The system uses the characteristics of the motor to determine the speed of rotation of the wheel. The procedure for measuring the speed of rotation of a steering wheel includes measurement of the current and voltage of the electric motor used for power assistance. The speed of rotation of the steering wheel is deduced from an approximation of the value of the global resistance (R) of the motor. The value of the electrical resistance is estimated in real time, by calculating n models of the motor for n different values of resistance. The estimation is effected w.r.t. the n models of the motor, by defining a criteria to minimize the error characteristic, and by searching for the minimum of the best polynomial approximation to a given degree using a set of points.