Stability of complex systems with mixed connection configurations under shared control

This paper presents a new stabilizing method for the control of complex systems operating in semi-automatic modes. The complex system is modeled by several spatially-coupled subsystems interconnected in parallel, serial and cycle configurations. Each subsystem is regulated by a dedicated autonomous controller that also allows for a manual control mode. An interconnection stability condition which takes the couplings between subsystems into consideration is derived from the renowned dis-sipative systems theory. Built upon this stability condition, decentralized stabilizing agents for autonomous controllers are subsequently deployed independently and segregatedly from the control algorithms. Due to this independence, human errors from man-machine interactions, that may destabilize the control systems, can be avoidable; also different types of control algorithms and controllers of subsystems are interoperable with the same stabilizing mechanism. To accomplish such tasks simultaneously, the stabilizing agents render overriding outputs for the automatic controllers, and at the same time, provide instability warning signals and manipulation guidance to the operators to successfully regulate the subsystems in the manual control mode, yet maintain the plant-wide stability. Real-time data of control inputs and plant outputs is exerted under the auspices of controller dissipativity indices and trajectories to stabilize the systems with closed-loop control and man-in-the-loop coexistence. Our main results are illustrated in simulation for a three-unit system.