Feedback control method based on direct servomechanism speed sensing and processing to reduce residual vibration

This paper describes one of the functional methods for suppression a two-mass system residual vibration. These vibrations are evoked due to the torsion plasticity of the mechanism kinematics chain members and acting of large moment of inertia. The method is based on comparison of the actual speed signals sensed by means of both the PMSM inbuilt internal encoder and external encoder. The external encoder measures the actual speed at the servomechanism end point (burdened with vibrations). By means of processing these signals is generated the correction signal. This signal consequently meets the control structure again as a speed feedforward signal. First of all the method was tested by means of mathematical model numerical simulations in Matlab Simulink. Right after its functionality has been proven in simulations was consequently implemented into the existing cascade control structure of standard servo control unit Siemens Sinamics S120 by means of so called DCC Chart engineering tool. The results of simulations as well as of the experiments made on the real system proved the ability of proposed method to effectively compensate the two-mass system torsional vibrations.