Pressure control techniques in freeze-drying

1.1 Pressure control techniquesThe pressure control techniques in industry, scientific applications or production is an open-ended area, and their related very challenging research and development are still going on. PID (Proportional Integral Derivative) controllers are the most common ones among the others, but with the latest developments in Artificial Intelligence (AI) fields, other methods like Fuzzy logic (FL) control has also become an alternative method for pressure control, where the process domains exhibit high parameters variations and PID method cannot be applicable. The pressure control methods selection heavily depends on the specifications of target application, hence not only one can particularly be emphasized. The most common Pressure control techniques would be listed as follows:
PID methodFuzzy logicMax pressure algorithmsReinforcement learningAdaptive controlSetpoint profile tracking (Bang-bang control)Pressure control systems have to perform a particular task in the target process considering some key functionalities like: system dynamism, control performance, stability, adaptability, accuracy, etc. PID (Proportional Integral Derivative) controllers provide most of those functionalities and they operate in a closed loop system (called PID loop) by which the system reads a sensor output, to provide a constant feedback, against which the desired actuator output may be calculated at a regular interval (e.g., time interval) known as a fixed loop rate. The operational principle of PID system can is illustrated in the Powerpoint figures of this Figshare publication, respectively.