A realization model to develop the autopilot system of ships by specializing MDA

This paper presents a method which is based on the Model-Driven Architecture (MDA) and functional blocks to realize effectively the autopilot systems of ships. It brings out an executable MDA process to cover completely the requirement analysis, design and deployment phases of these systems. This process also allows the determined design elements to be customizable and re-usable in the new applications of controlled ship steering systems. The paper indicates straightforwardly the ship dynamic model-to-be used, the Computation Independent Model (CIM) of a ship autopilot system, the Platform Independent Model (PIM) of this system by using the Real-Time Unified Modeling Language (UML), and its Platform Specific Model (PSM) implemented by the functional blocks. Furthermore, the important transformation rules are also brought out and applied to convert the identified PIM into PSM for implementing quickly this system with different industrial frameworks such as the IEC61499 in a programmable controller. Then, its deployment model completely is tested on a model ship with the predetermined program and control performance

Interval-based simulation of Zélus IVPs using DynIbex

Modeling continuous-time dynamical systems is a complex task. Fortunately some dedicated programming languages exist to ease this work. Zélus is one such language that generates a simulation executable which can be used to study the behavior of the modeled system. However, such simulations cannot handle uncertainties on some parameters of the system. This makes it necessary to run multiple simulations to check that the system fulfills particular requirements (safety for instance) for all the values in the uncertainty ranges. Interval-based guaranteed integration methods provide a solution to this problem. The DynIbex library provides such methods but it requires a manual encoding of the system in a general purpose programming language (C++). This article presents an extension of the Zélus compiler to generate interval-based guaranteed simulations of IVPs using DynIbex. This extension is conservative since it does not break the existing compilation workflow

Enclosing the behavior of a hybrid system up to and beyond a Zeno point

Even simple hybrid systems like the classic bouncing ball can exhibit Zeno behaviors. The existence of this type of behavior has so far forced simulators to either ignore some events or risk looping indefinitely. This in turn forces modelers to either insert ad hoc restrictions to circumvent Zeno behavior or to abandon hybrid modeling. To address this problem, we take a fresh look at event detection and localization. A key insight that emerges from this investigation is that an enclosure for a given time interval can be valid independently of the occurrence of a given event. Such an event can then even occur an unbounded number of times, thus making it possible to handle certain types of Zeno behavior

Modeling Basic Aspects of Cyber-Physical Systems

Designing novel cyber-physical systems entails significant, costly physical experimentation. Simulation tools can enable the virtualization of experiments. Unfortunately, current tools have shortcomings that limit their utility for virtual experimentation. Language research can be especially helpful in addressing many of these problems. As a first step in this direction, we consider the question of determining what language features are needed to model cyber-physical systems. Using a series of elementary examples of cyber-physical systems, we reflect on the extent to which a small, experimental domain-specific formalism called Acumen suffices for this purpose.Comment: Presented at DSLRob 2012 (arXiv:cs/1302.5082

An object-oriented design method to implement the mechatronic system control by using hybrid automata and real-time UML

In this paper, we present a method, which is based on hybrid automata and Real-Time Unified Modeling Language (UML) to analyze and design the control parts of mechatronic systems with input or output events and signals in order to effectively gather their structure and behaviour. We introduce step-by-step analysis and design activities of a controlled mechatronic system such as the specification of its hybrid automaton and realization hypotheses, the identification of object collaborations of this system, the identification of main control capsules, their ports and communication protocols, with their static and dynamic links. These activities are conducted by specializing the iterative life cycle of system development. Then, we indicate important hypotheses, which allow all the identified capsules of this system to make their evolutions. We apply this method to develop an Electro-Hydraulic Governor (EHG) system, which allows the frequency of an electro-hydraulic station to be stabilized

Online Cycle Detection for Models with Mode-Dependent Input and Output Dependencies

In the fields of co-simulation and component-based modelling, designers import models as building blocks to create a composite model that provides more complex functionalities. Modelling tools perform instantaneous cycle detection (ICD) on the composite models having feedback loops to reject the models if the loops are mathematically unsound and to improve simulation performance. In this case, the analysis relies heavily on the availability of dependency information from the imported models. However, the cycle detection problem becomes harder when the model's input to output dependencies are mode-dependent, i.e. changes for certain events generated internally or externally as inputs. The number of possible modes created by composing such models increases significantly and unknown factors such as environmental inputs make the offline (statical) ICD a difficult task. In this paper, an online ICD method is introduced to address this issue for the models used in cyber-physical systems. The method utilises an oracle as a central source of information that can answer whether the individual models can make mode transition without creating instantaneous cycles. The oracle utilises three types of data-structures created offline that are adaptively chosen during online (runtime) depending on the frequency as well as the number of models that make mode transitions. During the analysis, the models used online are stalled from running, resulting in the discrepancy with the physical system. The objective is to detect an absence of the instantaneous cycle while minimising the stall time of the model simulation that is induced from the analysis. The benchmark results show that our method is an adequate alternative to the offline analysis methods and significantly reduces the analysis time.Comment: \c{opyright} 2021. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0