Patent ID: 6037734
Filing Date: 2000-03-14
Classification: H02P

Abstract:
A motor velocity controlling method utilizing:an encoder for producing a plurality of different phase signals according to a rotation amount of a motor;detecting means for detecting all edges of said plurality of different phase signals; andmeasuring means for receiving said edges detected by said detecting means to measure intervals of edges succeeding with respect to time,said motor velocity controlling method comprising:a first process for obtaining a control target value on the basis of a value produced from said measuring means; anda second process for controlling a drive speed of said motor on the basis of a result of comparing said value from said measuring means and said control target value, wherein in said first process, said detecting means detects leading edges and trailing edges of A-phase and B-phase signals from said encoder, and said measuring means measures four edge intervals which are an interval between the leading edge of said A-phase signal and the leading edge of said B-phase signal, an interval between the leading edge of said B-phase signal and the trailing edge of said A-phase signal, an interval between the trailing edge of said A-phase signal and the trailing edge of said B-phase signal, and an interval between the trailing edge of said B-phase signal and the leading edge of said A-phase signal, to obtain said control target value for each of said four edge intervals, and updates a control command to said motor once per period of said four intervals.