ملخص
Abstract
The quadruple-tank process has been widely used in control literature to illustrate many concepts in multivariable control, particularly, performance limitations due to multivariable right half-plane zeros. The main feature of the quadruple-tank process is the flexibility in positioning one of its multivariable zeros on either half of the‘s’ plane A nonlinear and linear dynamic model for the quadruple-tank process are derived. The nonlinear model is derived from Johansson nonlinear dynamic system and describes the complicated dynamics of the physical plant when the system is setting in the non-minimum phase. The simulation results show that PID controllers have acceptable performances especially when the system is minimum-phase system while in the non-minimum-phase the controller is poor. Also it is shown that the linear quadratic Gaussian with loop transfer recover (LQG/LTR) is better than PID controller when the system is minimum-phase while in the non-minimum-phase the controller is not acceptable because (LQG/LTR) compensators generally cannot be designed for non-minimum-phase plants. Simulation results show that the proposed Decentralized fuzzy logic controller has a remarkable performance for tracking the multi step reference trajectories while at the same time it is robust against voltage changes. The Simulation results confirm the effectiveness of the proposed control methodology.