Novel dynamic modeling of feed drive system using subspace method

An innovative approach is proposed in this paper where the subspace identification method (SIM) is applied to develop a dynamic model of a feed drive system. Unlike the lumped parameter or finite element models, the SIM determines the state space model by utilizing the acceleration profile of the interpolator as the input signal and the acceleration of the moving platform as the output signal. It is found that the model obtained from the SIM can determine the dominant modes which are excited during the motion. The twisting and longitudinal modes are identified from the frequency response diagram and modal analysis. It is shown that the novel model can be used to evaluate the dynamic responses under various trajectories with different accelerations and jerks. Experimental results shows that the subspace model can predict the vibration of the XY table quite accurately with the RMS (root mean square) error less than 20%.