Multi objective reconfigurable control schemes for MIMO system

Abstract

Modern technological complex systems are generally interacting Multi-Input Multi-Output (MIMO) systems and rely on sophisticated control systems to meet the conflicting multi-objective requirements such as robust stability and transient performance. The objective of the present work is to design the Parametric Right Eigenstructure Assignment (PREA) based Multi-Objective Dynamic Reconfigurable Feedback Controller (MODRFC) for MIMO system against partial actuator failure using Non-dominated Sorting Genetic Algorithm-II (NSGA-II). The main contributions of this work include the following: Formulation of multi-objective control problem using PREA to achieve the following objectives: a) Robust stability and b) Good transient performance Development of linear discrete state space model for threetank MIMO system under fault-free and faulty conditions; Design of MODRFC schemes using NSGA-II against partial actuator failure; Qualitative and quantitative comparison of evolutionary algorithm based MODRFC against conventional MODRFC designed using classical optimization method. The conclusions of the work presented in this report are as follows: The Pareto-optimal fronts obtained using state feedback and output feedback controls show that the norm of feedback controller gain decreases as increase in condition number of closed loop eigenvectors. MODRFC through state feedback achieved the desired eigenstructure of the nominal system after the controller reconfiguration at the cost of sacrificing maximum control energy and guaranteed stability is obtained. Performance measures are tabulated for selected three pareto optimal solutions under 80% control effectiveness factor reduction in actuator 1. It is noted from the results that as ISE decreases, the control energy increases. Finally, the NSGA-II based MODRFC schemes are compared with the conventional schemes, which show that the NSGA-II based controller schemes provide more flexibility to optimize the controller parameters. newline newline newline