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This article covers research work about unmanned helicopters that is being developed by the Portuguese SME Introsys, S.A. in the context of a generic project targeting the development of a multi-robot system for landmine detection. As helicopters are complex multivariable nonlinear underactuated systems with strong coupling in some control loops, they are an interesting subject of research for the...
This paper introduces query mechanisms that allow automotive control-systems (using a distributed real-time database management system (RTDBMS)) to be queried, monitored and stimulated during run-time without violating its temporal properties. The mechanisms are completely transparent to the control application since they are handled by the RTDBMS. The COMET RTDBMS is extended with ad hoc capabilities...
The paper presents two new target platforms for the C-code generated by the Simulink/RTW toolboxes: the iFIX SCADA system and the GE Fanuc Series 90 PLCs. The presented solutions build interfaces to the C-code generated by the RTW toolbox and allow building the executable files that are functionally equivalent to the source Simulink diagrams. The executables are executed outside the Simulink directly...
The developer of logic control systems is faced with increasing complexity of the functions to be implemented and, at the same time, increasing demands on the reliability of the resulting software. To analyze the reliability of such complex systems formal methods can be applied. One area of the corresponding research is focused on the application of model checking techniques to Programmable Logic...
Many attempts have been made to implement supervisors derived by synthesis procedures peculiar to the supervisory control theory (SCT), most adopting the event-based supervisory control paradigm. However, when considering code generation schemata for programmable logic controllers (PLCs), hardware resources are limited and event tracking is hard to realize satisfactorily. Moreover, previous work has...
The behaviour verification of hybrid systems, for example for safety properties, is based on the computation of the reachable state space of a hybrid automaton modelling the system under study. In this paper we present a method for the computation of reachable set of uncertain hybrid affine systems. This method extends previous works which compute the reachable set of certain affine systems by abstracting...
Today there is a significant body of results of resource management in real-time systems. However, most of them are based on "open-loop" strategies and techniques that do not take into account application demands to dynamically adjust their behavior. To overcome this problem by focusing on control applications, we show a novel scheduling technique: large error first (LEF). This scheduling...
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