Liquid Level Control Performance Study of Conventional and Advanced Model-Based Controller for a Quadruple Tank System

Abstract

Liquid level control in a quadruple tank system (QTS) is crucial for various industrial
applications due to its multivariable nature. Conventional controllers frequently encounter
difficulties maintaining performance in complex applications, showing transient and steadystate
response difficulties. This study evaluates and compares the effectiveness of Model
Predictive Control (MPC) and Proportional-Integral-Derivative (PID) controller in
regulating the liquid level of a quadruple tank system to improve control precision, stability
and overall performance. The investigation utilized controller tuning to evaluate
performance metrics across different operational scenarios and constraints, including rise
time, settling time, and overshoot. The results demonstrate that MPC has superseded
performance compared to PID controller, resulting in faster response time, shorter settling
time, and decreased overshoot from the desired set point. As a result, constrained MPC
achieved a 15% decrease in overshoot and a 20% decrease in settling time compared to the
PID controller. To validate the robustness of MPC, set point changes were applied compared
with PID controller performance metrics. MPC transitioned smoothly between 12 and 18 cm
targets without overshoot and steady-state error. In contrast, PID incurred a persistent 0.5
cm error. This research contributes to the fact that MPC is a more effective method of
controlling QTS. MPC demonstrates better performance in both transient and steady-state
response.