Motor driven power steering device

Abstract

Abstract PURPOSE:To always generate a proper auxiliary torque by determining the rotating direction of a motor and a motor-current target value based on the relation between the previously stored relative angle displacement between input and output shafts and a motor current target value and in accordance with the detection of the relative angle displacement. CONSTITUTION:The output of an angle displacement detector 20 for detecting the relative displacement between the input and output shafts 10, 11 of a steering shaft is inputted into a microcomputer in a control device 23. And, based on the relation between the output of the angle displacement detector 20 and the relative angle displacement and the relation between the relative angle displacement and a motor current target value which are stored in the microcomputer, the rotating direction of the motor 18 and a motor-current target value are determined and outputted. In this case, in the microcomputer, these operations are carried at a speed of 50mum or less and repeated at every defined operating time of 2msec or less. Also, the relation between these are set to a small (large) nonlinear form in which the variation in the motor-current target value is small in a zone in which the relative angle displacement is small (large).

Inventors

• 👤 Toshihiko Omichi
• 👤 Mitsugi Fujiwara
• 👤 Shigeo Nishimura

Bibliographic Details