A parameter sensor including a conduit configured to contain a material is controlled. A first excitation applied to the conduit is determined. Motion of the conduit in response to the first excitation is determined. A second excitation to apply to the conduit is determined from the determined first excitation, the determined motion in response to the first excitation, a desired motion for the conduit, and a frequency response for the conduit. In particular, excitations may be iteratively determined and applied to the conduit, and motion signals representing motion of the excited conduit may be processed to generate process parameter estimates, such as mass flow rate estimates. The frequency response may be assumed to be time-invariant, or may be adaptively estimated. The invention may be embodied as methods, apparatus and computer program products.