Abstract
This paper presents the development and implementation of a two-degree-of-freedom, model-based controller designed to enhance the efficiency and flexibility of a certain class of circuits used in thermo-hydraulic applications. The controller addresses significant challenges such as time-variable transport delays and actuator coupling, which are common in dynamic testing environments. By utilising a model-based control approach and the Smith predictor configuration, the proposed controller simultaneously tracks supply temperature and mass flow rate with improved performance compared to the proportional–integrative–derivative (PID) controller used in our laboratory. The system’s effectiveness is demonstrated through a virtual hydraulic complex model developed in the OpenModelica environment and experimental tests, following the implementation of the controller in the laboratory real-time control software. Both the simulation and experimental results indicate that the controller can closely follow pre-programmed temperature and flow rate waveforms while effectively rejecting disturbances, with an RMSE reduction of up to about 80% under the specific test protocol used in this work, making it suitable for applications required to deal with the above constrains, such as laboratory dynamic testing and thermo-mechanical and chemical process regulation.