AUTOMATIC MECHANICAL RESONANT FREQUENCY DETECTOR AND DRIVER FOR SHUTTLE PRINTER MECHANISM

摘要

The detected phase difference between a sensed motion velocity signal and an electric motor driving signal is used to drive a phase-locked loop which automatically generates a sinusoidal reference signal having a frequency substantially equal to the instantaneous natural mechanical resonant frequency of the driven mechanism. The sinusoidal reference signal is then combined with the sensed velocity feedback signal to generate the motor driving signal required to maintian resonant driving conditions. Low frequency compensation is also provided in the velocity control loop. The sinusoidal velocity reference signal is initially generated in digital form by counting clock signals which are caused to occur at a rate corresponding to the desired frequency of the sinusoidal reference signal.