Active Vibration Isolation Control: Comparison of Feedback and Feedforward Control Strategies Applied to Coriolis Mass-Flow Meters

In this paper we describe the design, implementation and results of multi degree of freedom (DOF) active vibration control for a Coriolis mass-flow meter (CMFM). Without vibration control, environmental vibrational disturbances results in nanometre movement of the fluid-conveying tube which causes erroneous mass-flow measurements. In order to reduce the transmissibility from external vibrations to the internal tube displacement active vibration control is applied.A comparison of a feedback control strategy (adding virtual mass and skyhook damping) and an adaptive feedforward control strategy is made, taking into account the sensor noise levels. Theoretic results are validated with a multi-DOF experimental setup, showing up to 40 dB reduction of the influence of external vibrations. The amount of reduction is limited by the sensor noise levels.