A comprehensive decoupling active disturbance rejection control for a gas flow facility

Based on the linear active disturbance rejection control (LADRC), a comprehensive decoupling controller for gas flow facilities is presented to guarantee stability and a fast response during the process of gas flowmeter performance tests. First, a mathematical model is developed to describe the pressure-flow coupling system. Then, a step response method is applied to identify parameters of this model. To realize the effective decoupling control, the static coupling part is introduced into the LADRC design. The overall effect of the dynamic coupling part among two channels, the internal uncertainties and the external disturbance, are treated as total disturbance, which is estimated using the extended state observer and cancelled out by the control law. After estimating and cancelling, the pressure-flow coupling system can be transformed into two single input single output subsystems with the form of cascade integrators. Then two proportional differential controllers are applied to control the two simplified subsystems. Simulation and experimental results show that the proposed algorithm has a shorter settling time, a more effective decoupling effect and a greater capability of disturbance rejecting and stronger performance robustness in gas flow facility than conventional proportional-integral-derivative algorithms.