PID controller tuning for integrating processes.

Area of Science:

• Control Systems Engineering
• Process Control

Background:

• Proportional-Derivative (PD) controllers are used for integrating processes.
• Minimizing Integral Squared Error (ISE) yields optimal PD controller parameters.
• Standard PD controllers offer good servo response but poor load disturbance rejection.

Purpose of the Study:

• To improve the load disturbance rejection of PD controllers for integrating processes.
• To achieve satisfactory closed-loop performance by modifying the ISE minimization criterion.
• To provide guidelines for controller tuning and analytical expressions for parameter correlation.

Main Methods:

• Minimizing the ISE criterion with a constraint on the Nyquist curve slope at the gain crossover frequency.
• Developing guidelines for selecting the gain crossover frequency and Nyquist slope.
• Comparing the proposed method with existing control strategies for integrating plants.

Main Results:

• The proposed constrained optimization method yields superior load disturbance rejection compared to existing techniques.
• Satisfactory setpoint response is maintained alongside improved disturbance rejection.
• Analytical expressions are derived for controller and plant model parameter correlation, simplifying controller design.

Conclusions:

• The constrained ISE minimization offers a robust approach for PD controller tuning in integrating processes.
• The method effectively balances servo response and disturbance rejection.
• The provided guidelines and analytical expressions facilitate practical implementation and enhance control system performance.