Process parameter sensor apparatus, methods and computer program products using force filtering

Abstract

A process parameter associated with a material contained in a vibrating structure is estimated. A plurality of motion signals representing motion at a plurality of locations of the vibrating structure are received. The received plurality of motion signals are force filtered with a force filter to produce a force-filtered motion signal that discriminates motion attributable to a force of interest among a plurality of forces acting on the vibrating structure. A process parameter associated with the material contained in the vibrating structure is estimated from the force filtered motion signal. Preferably, a plurality of motion signal values is generated from the received plurality of motion signals, and force filtering includes the step of applying a force filter matrix to the plurality of motion signal values to produce a force filtered motion signal value. A process parameter, such as mass flow, density or the like, is then estimated from the force filtered motion signal value. According to an aspect of the present invention, the force filter matrix represents a product of a frequency response function matrix for the vibrating structure, a force selectivity matrix and an inverse of the frequency response function matrix. Methods for estimating structural motion, along with related apparatus and computer program products, are also discussed.