A novel hyperbolic tangent-based PID controller tuned by the artificial lemming algorithm for nonlinear steam...

Area of Science:

• * Control Systems Engineering
• * Thermodynamics and Heat Transfer
• * Artificial Intelligence in Engineering

Background:

• * Precise pressure control in shell-and-tube steam condensers is critical for thermal efficiency and safety in power plants.
• * Conventional proportional-integral-derivative (PID) controllers exhibit limitations in handling the nonlinear dynamics of these systems, resulting in poor performance.
• * Existing controllers often suffer from overshoot, slow settling times, and reduced robustness in complex operational environments.

Purpose of the Study:

• * To develop and evaluate a novel hyperbolic tangent-based PID (tanh-PID) controller for enhanced pressure regulation in nonlinear steam condensers.
• * To introduce smooth nonlinear gain modulation for improved damping and transient response characteristics.
• * To optimize the tanh-PID controller using the artificial lemming algorithm (ALA) for minimizing performance errors.

Main Methods:

• * Development of a hyperbolic tangent-based PID (tanh-PID) controller with nonlinear gain modulation.
• * Optimal tuning of the tanh-PID controller using the artificial lemming algorithm (ALA) to minimize integral of time-weighted absolute error (ITAE).
• * Simulation studies using a nonlinear condenser model including steam-air interactions and hot-well dynamics, benchmarked against other algorithms and controllers.

Main Results:

• * The ALA-tuned tanh-PID controller achieved the lowest ITAE (2.1189), fastest rise time (0.5960 s), and minimal settling time (12.4799 s).
• * The proposed controller demonstrated minimal overshoot (5.8056%) and near-zero steady-state error (4.0776 × 10⁻⁴%), outperforming PI, FOPID, and other optimization algorithms.
• * Robustness analyses confirmed superior disturbance rejection and reliable reference tracking under dynamic uncertainties.

Conclusions:

• * The proposed ALA-tuned tanh-PID controller offers a high-performance, low-complexity solution for precise pressure regulation in industrial steam condensers.
• * The nonlinear gain modulation effectively enhances damping behavior and transient shaping, addressing limitations of conventional controllers.
• * The methodology shows significant potential for real-time deployment, improving operational efficiency and safety in power generation systems.