Abstract: There is provided a control device for a power steering device that provides stable steering feeling in the vicinity of a stroke end. The control device for the power steering device is configured to calculate a stopper torque that is a steering force in a direction opposite to a direction causing a turning angle to approach a stopper angle, based on a steering torque signal, when the turning angle approaches the stopper angle accompanied with a steering operation of a steering wheel, and configured to calculate a motor command signal that is used to drive a power-driven motor, based on a driving condition of a vehicle and the stopper torque.

Abstract: A transverse gradient current Ic which is larger than a basic assist current Ib is outputted, as a current command value, to motor driving section when direction correspondence judgment section 11 judges that rotation directions of first and second rotation angle signals ?1 and ?2 correspond with each other, when an advancing phase judgment section 12 judges that a phase of the second rotation angle signal is advanced, and when a phase variation judgment section 14 judges that a phase advance state of the second rotation angle signal ?2 continues.

Abstract: A transverse gradient current Ic which is larger than a basic assist current Ib is outputted, as a current command value, to motor driving section when direction correspondence judgment section 11 judges that rotation directions of first and second rotation angle signals ?1 and ?2 correspond with each other, when an advancing phase judgment section 12 judges that a phase of the second rotation angle signal is advanced, and when a phase variation judgment section 14 judges that a phase advance state of the second rotation angle signal ?2 continues.

Abstract: For compensation for loss of a steering assist force due to friction of a steering mechanism, when calculating a friction correction value for the compensation, in an electronic control unit 6, a static friction and a kinetic friction are distinguished, and the calculation is made by combining the static friction correction value Sf and the kinetic friction correction value Kf according to each friction. It is therefore possible to make a proper friction loss compensation according to type of the friction.

Abstract: A power steering apparatus has a first characteristic which is a characteristic of a command signal with respect to steering torque and a second characteristic which is a characteristic different from the first characteristic. When switching is to be made to a characteristic selected from between the first and second characteristics, an interpolation characteristic intermediate between the first and second characteristics is calculated so that the characteristic used before switching of the characteristics gradually approaches the characteristic to be used after the switching, and a characteristic switching time for switching between the first and second characteristics is variably controlled in accordance with the steering torque.

Abstract: For compensation for loss of a steering assist force due to friction of a steering mechanism, when calculating a friction correction value for the compensation, in an electronic control unit 6, a static friction and a kinetic friction are distinguished, and the calculation is made by combining the static friction correction value Sf and the kinetic friction correction value Kf according to each friction. It is therefore possible to make a proper friction loss compensation according to type of the friction.

Abstract: A power steering apparatus has a first characteristic which is a characteristic of a command signal with respect to steering torque and a second characteristic which is a characteristic different from the first characteristic. When switching is to be made to a characteristic selected from between the first and second characteristics, an interpolation characteristic intermediate between the first and second characteristics is calculated so that the characteristic used before switching of the characteristics gradually approaches the characteristic to be used after the switching, and a characteristic switching time for switching between the first and second characteristics is variably controlled in accordance with the steering torque.

Abstract: Electric power steering system has steering mechanism; input and output shaft side rotation angle sensors detecting rotation angles of input and output shafts; operation circuit calculating command current for an electric motor; rotation direction judging circuit judging whether rotation directions of the input and output shafts are identical; advanced-phase judging circuit judging which phase of input and output shaft side rotation angle signals (S1, S2) is advanced; normal/reverse input judging circuit judging that (i) when both rotation directions are identical and S1 is advanced, input is normal input and (ii) when both rotation directions are identical and S2 is advanced, input is reverse input; and command current correcting circuit. The command current correcting circuit corrects the command current so that when the normal input is judged, torque in the same direction as input shaft rotation direction generated by the electric motor is greater than a case of reverse input judgment.