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.

Abstract: An identification is made of an abnormal condition in a motor due to an influence of a disturbance voltage, without addition of hardware, by estimating the disturbance voltage based on a target voltage and actual current flowing in the motor.

Abstract: In the conventional electric power steering control system, a gain by which an approximate differentiation value of a torque signal is multiplied comes to be large at high speed driving. Therefore, a problem exits in that unstable feel of steering increases, thereby steering convergence getting worse. An electric power steering control system includes a variable type torque differential operation device 104A that makes variable a differential time constant at the time of outputting a second motor current, and a time constant determining device 105X that commands the time constant to the variable type torque differential operation device 104A. The time constant determining device 105X determines the time constant in response to any change in not less than one signal selected and used in an arbitrary manner out of a speed signal 81, a torque signal 82, a yaw rate signal 83 and a steering rate signal 84.

Abstract: A judgment is made of an abnormal condition of a motor due to an influence of a disturbance voltage without addition of hardware by estimating the disturbance voltage on the basis of a target voltage and an actual current of the motor.

Abstract: In the conventional electric power steering control system, a gain by which an approximate differentiation value of a torque signal is multiplied comes to be large at the time of high speed travelling. Therefore upon conducting a quick steering for a lane change or avoidance of danger, a problem exits in that unstable feel of steering increases thereby steering convergence of vehicle getting worse. In the invention, there are provided a variable type torque differential operation device 104A that makes variable a differential time constant at the time of outputting a second motor current, and a time constant determining device 105X that commands the time constant to the variable type torque differential operation device 104A. The time constant determining device 105X determines the time constant in response to any change in not less than one signal selected and used in an arbitrary manner out of a vehicle speed signal 81, a steering torque signal 82, a yaw rate signal 83 and a steering rate signal 84.