Unsteady air flow measurement method based on adaptive tracking differentiator for pneumatic system

Abstract

When using a flowmeter to measure unsteady air flow in the pneumatic control system, problems such as high cost and pressure loss are often encountered. It is an available method to measure the unsteady flow rate using isothermal chamber through direct differentiation of pressure signal with a traditional fixed parameter differentiator, but the adaptability of this method is insufficient due to its narrow dynamic range. To this end, an improved adaptive tracking differentiator which can adaptively adjust the control parameters according to the changes of pressure signal and pressure tracking error was proposed for unsteady air flow measurement. The algorithm structure of the adaptive tracking differentiator was designed. Moreover, theoretical simulation and flow measurement experiments under multiple working conditions were carried out. The simulation and experiment results showed that the flow measurement method based on improved adaptive tracking differentiator effectively measured the unsteady flow in a wide dynamic range, and had the advantages of more simplified process and lower cost than traditional method.