Reconfigurable Cooperative Control of Networked Lagrangian Systems Under Actuator Saturation Constraints

In this paper, a reconfigurable control strategy is proposed for state synchronization and tracking control of networked (electro-) mechanical Euler-Lagrange (EL) systems that are subject to input saturation constraints that may arise due to actuator faults or failures. The reconfigurable controller consists of three main parts. The first part, known as the nominal controller, is a distributed controller that is employed to guarantee global stability of the multiagent networked EL system provided that certain mild connectivity conditions are satisfied in absence or presence of actuator saturation constraints. The second part, known as the reconfigured controller, is a constrained nonlinear smooth distributed controller that has a different structure and gains from the nominal controller. This controller can preserve the overall control objectives in presence of actuator faults and actuator saturation constraints. The third part is a switching strategy between the nominal and the reconfigured controllers. Global stability as well as asymptotic convergence of the synchronization and the tracking errors to origin for switchings under certain conditions between the nominal and the reconfigured controllers with non-vanishing dwell-times for a fixed network topology are shown to be guaranteed. Simulation results are reported to demonstrate and validate the merits of the proposed controllers.