The invention relates to the technical field of
motor speed measurement by a four-way parallel sampling T-method
motor speed measurement method, and specifically relates to a method for obtaining the rotational speed of an incremental photoelectric
encoder applied to a
servo system at
low speed operation. First, the incremental photoelectric
encoder Output the
square wave signals of phase A and phase B to the
signal processing controller, set the trigger signals of the four timers as: rising edge of phase A, falling edge of phase A, rising edge of phase B, falling edge of phase B, and then timing The
timer starts counting the high-frequency
clock pulse
signal with a cycle of T, when the
timer encounters the same A and B
phase change edges again, it records the number of high-frequency
clock pulse signals, and at the same time clears the counter and starts the next count cycle, and then calculate the
motor speed according to the number M of high-frequency
clock pulse signals, and update the speed every time the
timer finishes counting the high-frequency clock pulse signals, thus completing the
speed measurement of the motor. The speed measuring method of the invention has high speed measuring precision when measuring the
low speed of the motor, low dynamic speed measuring error and high dynamic response speed.