Robust Control of Systems over Communication Network

 

Vojislav Z Filipović

 

In this paper the problem of robust control of constrained linear dynamic systems, in the presence of communication networks with queues, is considered. The communication network is between the process and the controller. We assume that the queue is in the sensor. The closed-loop system may face the problem of induced random delays caused by the communication network and that delay would deteriorate the system performance as well as its stability. Digital control systems with random but bounded delay in the feedback loop can be modeled as finite dimensional discrete-time jump linear systems with transition jumps being modeled as finite state Markov chains. The queue is modeled as a nonlinear systems to which feedback linearisation methodology is apllied. Then the complete system (process, communication network, queue) can be presented as a discrete-time jump system. For such a system, without unmodeled dynamics, the constrained quadratic control is proposed. The analysis of the system is then performed in the presence of unmodeled dynamics. This kind of systems has wide applications in military systems and process control systems.

Key words: communication system, communication network, network control, robust control, dynamic system, linear system, random delay.