Abstract: In an electric power steering control system, a phase compensator of the steering torque is made of an analog circuit and an anti-phase compensator is made by the software of a microcomputer, thereby to eliminate the changes in the gain and the phase by the phase compensator of the analog circuit near the oscillation frequency, so that the steering torque signal equivalent to that of no phase compensation necessary for the computation at the observer is computed from the phase-compensated steering torque signal.

Abstract: In an electric power steering control system, a phase compensator of the steering torque is made of an analog circuit and an anti-phase compensator is made by the software of a microcomputer, thereby to eliminate the changes in the gain and the phase by the phase compensator of the analog circuit near the oscillation frequency, so that the steering torque signal equivalent to that of no phase compensation necessary for the computation at the observer is computed from the phase-compensated steering torque signal.

Abstract: Intended is to solve the problem of an increase in the cost of an electric power steering control system, the oscillations of which are suppressed by estimating and feeding back the oscillation frequency components of a motor rotating speed through an observer from a steering torque signal and a current signal for driving a motor, no matter whether a phase compensator might be made of an analog circuit or a software. In order to solve this problem, there is provided the electric power steering control system, in which the phase compensator of the steering torque is made of an analog circuit and in which an anti-phase compensator is made over the software of a microcomputer, thereby to eliminate the changes in the gain and the phase by the phase compensator of the analog circuit near the oscillation frequency, so that the steering torque signal equivalent to that of no phase compensation necessary for the computation at the observer is computed from the phase-compensated steering torque signal.

Abstract: Intended is to solve the problem of an increase in the cost of an electric power steering control system, the oscillations of which are suppressed by estimating and feeding back the oscillation frequency components of a motor rotating speed through an observer from a steering torque signal and a current signal for driving a motor, no matter whether a phase compensator might be made of an analog circuit or a software. In order to solve this problem, there is provided the electric power steering control system, in which the phase compensator of the steering torque is made of an analog circuit and in which an anti-phase compensator is made over the software of a microcomputer, thereby to eliminate the changes in the gain and the phase by the phase compensator of the analog circuit near the oscillation frequency, so that the steering torque signal equivalent to that of no phase compensation necessary for the computation at the observer is computed from the phase-compensated steering torque signal.