Vibration suppression and tracking control of a flexure-jointed motion stage mechanism using LTV-FIR command filtering

This paper presents a linear time-varying (LTV) prefilter design for residual vibration suppression in LTV motion systems. As tracking performance can be affected by delay effects from prefiltering, an additional moment constraint is introduced in the prefilter synthesis equations for tracking of constant velocity commands. Inclusion of the moment constraint can result in higher prefilter gain (H2 norm) which leads to overshoot in the transient response. It is shown how this effect can be reduced by noncausal prefiltering with specified preview time. The LTV-FIR prefilter is applied experimentally to a multi-flexure X-Y motion stage mechanism where the position-dependent dynamics are captured by interpolation of a set of identified LTI models. The experimental results confirm that the prefilter with input preview can reduce settling time and overshoot compared with the causal prefilter, while maintaining good tracking performance.