Output Feedback Predictor Compensating Time-delays in Distributed Real-time Systems

L. Samaranayake, M. Leksell (Sweden), and S. Alahakoon (Sri Lanka)


Distributed, Real-Time, Time-Delay, Output feedback,Predictor based compensator


Inherent time-delays in distributed real-time control sys tems can degrade the performance or unstable the sys tem unless treated properly. Standard delay compensa tion schemes usually include time stamped measurements, which require clock synchronization at different nodes. This needs periodic re-synchronization to minimize the im pact of clock drift, consuming additional bandwidth. Fur ther, the controller to actuator delay is unknown prior to the controller calculation, where probability distribution based complicated methods are required, to know it in advance. In this paper, a plant model based predictor is cascaded to the state observer to predict the states corresponding to the next sample. These states are then used in the controller to derive the next control signal, which is released just af ter reading the next sample. This completely eliminates clock synchronization and complications in delay compen sation. The proposed method is implemented in simulation in a real-time environment for open loop stable and unsta ble systems.

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