Analysis and Compensation of Network Induced Communication Delays for Distributed Control Systems

The control of physical systems with a computer is becoming commonplace. In addition, computer networking is now used to perform spatially distributed interrelated functions. Sensors, controllers and actuators can then be interconnected via the network to form a distributed control loop. However, due to the asynchronous nature of network communications, time varying transport delays are introduced into the feedback control loop. These network induced delays significantly degrade the performance of control systems. This is illustrated and discussed in this paper. Further, different compensation strategies proposed by control researchers are reported. Finally, a procedure has been derived and exemplified to integrate time varying network induced delays within the control design method traditionally used with time invariant systems