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PurposeThe aim of this work is to propose a logical‐based approach for deriving the critical scenarii from a differential predicate transition Petri nets model and proof tree, to evaluate diagnosis and safety of hybrid systems.Design/methodology/approachThe new approach integrates the Petri net model and linear logic. The design process is twofold: first, it considers the specific translation from Petri net to linear logic, and, second, it studies the relationship between the order of the rule application in the sequent proof and the processes associated with the same reachability problem.FindingsWith linear logic and Petri net it is proved that, from a canonical proof tree, a partial order can be derived (based on causality point of view) of transition firing and focusing the search of the parts of the model that are interesting for safety analysis. Each scenario is given by a partial order between the events necessary for the occurrence of the feared event.Originality/valueThis paper deals with safety in design of hybrid systems. For this purpose, it is important to characterize feared behaviours (which are critical) in the early design stage.

The induction machine is experiencing a growing success for two decades by gradually replacing the DC machines and synchronous in many industrial applications. This paper is devoted to the study of advanced methods applied to the command of the asynchronous machine in order to obtain a system of control of high performance. While the criteria for response time, overtaking, and static error can be assured by the techniques of conventional control, the criterion of robustness remains a challenge for researchers. This criterion can be satisfied only by applying advanced techniques of command. After mathematical modeling of the asynchronous machine, it defines the control strategies based on the orientation of the rotor flux. The results of the different simulation tests highlight the properties of robustness of algorithms proposed and suggested to compare the different control strategies.

Abstract:The modern technology advances to a point where it is possible and extensively desirable to improve reliability and the technical process safety. This is achieved by computer implanted FDI procedures (Fault Detection and Isolation). However, the malfunction of actuators, sensors and of the process components, as well as erroneous actions of human operators can have some disastrous consequences in high risk systems such as: Spatial engines (Astronomy), aircrafts (Aviation), nuclear reactors and chemical plants. Thus, each failure or fault can lead to shutdowns or a rupture of service and consequently a plant output reduction. There is an improvement of consciousness and attitude to possible disaster provoked by failures that could enable a failure tolerating system development. Such system must maintain a optimal performance during normal operating conditions and must handle encountered critical situations during which the system's conditions are abnormal that is by performing of detection and diagnosis procedures and reconfiguration according to accurate software programs. In this study, we focus on the diagnosis of the flexible manufacturing systems which are described by a model based on the Petri nets. The basic idea consists of residuals generators resulting from the equation of marking evolution of the process and having appropriated structures to facilitate fault isolation.