Pid Tuning Rule for Pressure Control Applications

In pressure control applications, servo-valves or variable displacement pumps are used to meter the flow into a supply line or a chamber with relatively constant capacity, thereby controlling its pressure under the influence of disturbances such as flows in and out of the controlled volume. For most applications proportional integral derivative (PID) controllers are suited and widely used in research and practice. However, tuning of PID parameters for pressure control is usually done by trial and error method due to the lack of applicable tuning rules for this case. The paper examines the dynamics of valve controlled pressure applications and proposes a set of effective but simple PID feedback gain formulas. They can be implemented by practitioners on the basis of data that in most cases is available from plant drawings and the valve data sheet. The tuning rule's parameters are based on a straight forward frequency response design. They yield swift and robust performance in simulation and experiment.