Observer Synthesis For Linear/nonlinear Dynamical Systems Subject To Measurement Delays

Abstract

In this research, problems associated with communication delays on the stability of formation of a group of unmanned vehicles is examined and solution to this problem is proposed. Ideally, it is required that the information transfer between the vehicles participating in a cooperative task be available immediately. But, in reality, there is always a delay between the instants at which the information is transmitted by one vehicle and the instant at which it is received by the other vehicles in the formation. A state observer is used to estimate the time delayed signal. The observer consists of two dynamic systems connected in cascade. The delayed output signal is used to estimate the current states using this cascade observer. The reconstruction of the states is done at several sub-intervals within the delay window. Two types of time delays profiles are considered for analysis. Initially, the delays are assumed to be known constants. Next, the assumption is relaxed to study the effects of known time varying delays are examined. In both the cases, the structure of the state observer remains unchanged. The analysis is done for both continuous-time and discrete-time linear time invarivant systems and continuous-time nonlinear system. The state observer, in each of these cases is an guarantees either asymptotic or exponential while convergence to the true states.