System for controlling electric power steering

A system for controlling electric power steering including an electric motor for generating an assist force;

• steering torque detection means for detecting steering torque;
• basic assist command-value determination means for determining a basic assist command-value from a steering torque detection signal;
• steering torque differentiation command-value determination means for determining a steering torque differentiation command-value from the steering torque detection signal;
• motor current detection means for detecting output of said electric motor;
• and output control means for controlling output of said electric motor, in which the output control means controls the output of the electric motor in response to a motor current control signal at a reference level resulting from the addition of a motor current detection signal and a motor current command-value signal consisting of the basic assist command-value and the steering torque differentiation command-value, said system for controlling the electric power steering, comprising:
• signal level decision means for selecting a reference level or an amplification level in response to the steering torque detection signal or the motor current command-value signal;
• first adjustment means for carrying out the selection of the reference level or the amplification level for a signal level of the motor current command-value signal;
• second adjustment means for carrying out the selection of the reference level or the amplification level for a signal level of the motor current detection signal, analog-to-digital conversion means for converting the signal outputted from said second adjustment means into a digital signal;
• and
• third adjustment means for adjusting the motor current control signal to be at the reference level,
• wherein each of said first adjustment means and said second adjustment means decides the signal level in response to a signal level decision signal sent from said signal level decision means, and said third adjustment means adjusts the motor current control signal to be at the reference level in response to the signal level decision signal and inputs the adjusted signal to said output control means.