Active damping of torsional vibrations in servodrives

<p>In the paper the problems of active damping of torsional vibrations in small power high dynamic<br>servo drives are presented. Only solutions with position sensor (encoder) i. e. without other sensor are<br>taken into consideration. Eventual observers or estimators of state variables needed for control as well<br>as all elements of signal processing are treated as a integral part of the controller. The total time delay<br>introduced into speed control loop due to digital control and processing is important factor from point<br>of view of ability for active damping of vibration. The adequate "stiffness factor" together with natu-<br>ral torsional frequency, anti-resonance frequency and load-to-motor inertia ratio are used as general-<br>ised parameters of the system. The aim of the work is to test the ability of various speed controllers<br>for damping of the vibration in the system at various values of its stiffness and inertia. The following<br>structures of speed controller are taken into consideration and preliminary tested: the digital PI and<br>PID controllers, the state controller with state observer, slow resonance ratio controller and linear<br>quadratic compensator with Kalman filter. In all cases there are given the proposed control structures<br>and results, obtained by the authors during their preliminary simulation investigation. Conclusions<br>related to the operation of the separate controllers and further investigations are given.