Thermodynamic and friction dynamics modeling of pneumatic control valves for precision control applications

This study develops a comprehensive mathematical model of a single-acting pneumatic control valve by thoroughly analyzing its thermodynamic and dynamic characteristics. Considering the compressibility of the gas, energy losses, and temperature variations during intake and exhaust processes, a distributed pressure dynamic equation is formulated to better capture the nonlinear behaviors of a pneumatic servo system. The LuGre friction model is integrated with parameter optimization via a convolutional evolutionary algorithm, thereby enhancing the depiction of friction transitions and system dynamics. Validation through experiments and simulations demonstrates excellent predictive performance, with RMSE of 1.5, MAE of 0.96, and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"> <mml:mrow> <mml:msup> <mml:mrow> <mml:mi mathvariant="bold-italic">R</mml:mi> </mml:mrow> <mml:mrow> <mml:mn>2</mml:mn> </mml:mrow> </mml:msup> </mml:mrow> </mml:math> of 0.9967. Residual analyses confirm the model’s robustness and precision. This work provides a robust foundation for the design of advanced control strategies, enhancing the accuracy and reliability of pneumatic systems in complex conditions.