Modeling and simulation of the two-tank system within a hybrid framework

Most real-world dynamical systems are often involving continuous behaviors and discrete events, in this case, they are called hybrid dynamical systems (HDSs). To properly model this kind of systems, it is necessary to consider both the continuous and the discrete aspects of its dynamics. In this paper, a modeling framework based on the hybrid automata (HA) approach is proposed. This hybrid modeling framework allows combining the multi-state models of the system, described by nonlinear differential equations, with the system’s discrete dynamics described by finite state machines. To attest to the efficiency of the proposed modeling framework, its application to a two-tank hybrid system (TTHS) is presented. The TTHS studied is a typical benchmark for HDSs with four operating modes. The MATLAB Simulink and Stateflow tools are used to implement and simulate the hybrid model of the TTHS. Different simulations results demonstrate the efficiency of the proposed modeling framework, which allows us to appropriately have a complete model of an HDS

Generating Test Sequences and Slices for Simulink/Stateflow Models

In a typical software development project more than 50 percent of software development effort is spent in testing phase. Test case design as well as execution consumes a lot of time. So automated generation of test cases is highly required. In our thesis we generated test sequences from Simulink/Stateflow, which is used to develop Embedded control systems. Testing of these systems is very important in order to provide error free systems as well as quality assurance. For these purpose Test cases are used to test the systems. We developed the test sequences which are use to generate test cases. First, we represent the System using Simulink/Stateflow models. For this purpose normally we use Simulink tool, which is available in the MATLAB. We developed the dependency graph from the SL/SF model. For Simulink part of the model we use Out put dependency and for the Stateflow part of the model we use Control dependency graph. From those graphs we generate the test sequences. Simulink/Stateflow models often consist of more than ten thousand blocks and a large number of hierarchi-cal levels. In this, we present an approach for slicing Simulink/Stateflow models using dependence graphs from the automotive and avionics do-main. With slicing, the complexity of a model can be reduced to a given point of interest by removing unrelated model elements

Design of embedded controller using hybrid systems for integrated building systems

The design of controllers for integrated building systems has been traditionally carried out using basic techniques validated frequently by simulation. However, the demands on occupants’ comfort, safety and energy consumption increase speedily as the current controllers used in buildings are not efficient and enough flexible to be adapted to any changes. To investigate such issues, this paper focuses mainly on the design of embedded control systems for integrated building plants. So therefore, the challenges of modeling embedded controller for building heating system are treated at higher-level of abstraction with the help of sophisticated tools and new development techniques. Particularity, this paper concerns the relevance and reliability of integrating distributed control and building performance simulation environments by run-time coupling, over TCP/IP protocol suite. In addition, this paper involves a case-study with an important setup where the simulated results are obtained within the use of run-time coupling approach

Systems engineering languages for modeling and analyzing supervisory control structures in cyber-physical systems

In today’s world, a new generation of high-tech cyber-physical systems are becoming an integral part of our societies and their impact is only going to increase within the next years. Because of their importance, the companies that develop these systems use proper systems engineering modeling tools to help with the design and development of these types of systems and to accelerate the whole development process. In this thesis, 4 very popular modeling tools/languages are being tested and evaluated in terms of their capabilities for model-based systems engineering. These tools are Simulink&Stateflow from MATLAB, Modelica, MechatronicUML and SysML. In order to do that, a proper introduction of the systems engineering process is presented to set the criteria in which the different tools/lan- guages will be evaluated. To support the evaluation process, a case study is presented with the CIF3 language that will be attempted with all the other languages/tools. Each modeling lan- guage/tool has been evaluated individually at first and then together with the others in the end. In addition to the first evaluation, a proper basic introduction of all the modeling concepts that each tool uses for modeling cyber-physical systems is provided and the building of the case study as well. After that, in the second evaluation, the languages are extensively compared against each other in terms of all the criteria set previously to see exactly the scope of capabilities that each tools has. As a result from the two evaluations, a definitive review for each language/tool is presented addressing their overall scope of capabilities, main strong features, main uses, possible ways of improving and future development.Outgoin

Simulator Semantics for System Level Formal Verification

Many simulation based Bounded Model Checking approaches to System Level Formal Verification (SLFV) have been devised. Typically such approaches exploit the capability of simulators to save computation time by saving and restoring the state of the system under simulation. However, even though such approaches aim to (bounded) formal verification, as a matter of fact, the simulator behaviour is not formally modelled and the proof of correctness of the proposed approaches basically relies on the intuitive notion of simulator behaviour. This gap makes it hard to check if the optimisations introduced to speed up the simulation do not actually omit checking relevant behaviours of the system under verification. The aim of this paper is to fill the above gap by presenting a formal semantics for simulators.Comment: In Proceedings GandALF 2015, arXiv:1509.0685

Sequence-Based Specification of Embedded Systems

Software has become integral to the control mechanism of modern devices. From transportation and medicine to entertainment and recreation, embedded systems integrate fundamentally with time and the physical world to impact our lives; therefore, product dependability and safety are of paramount importance. Model-based design has evolved as an effective way to prototype systems and to analyze system function through simulation. This process mitigates the problems and risks associated with embedding software into consumer and industrial products. However, the most difficult tasks remain: Getting the requirements right and reducing them to precise specifications for development, and providing compelling evidence that the product is fit for its intended use. Sequence-based specification of discrete systems, using well-chosen abstractions, has proven very effective in exposing deficiencies in requirements, and then producing precise specifications for good requirements. The process ensures completeness, consistency, and correctness by tracing each specification decision precisely to the requirements. Likewise, Markov chain based testing has proven effective in providing evidence that systems are fit for field use. Model-based designs integrate discrete and continuous behavior; models have both hybrid and switching properties. In this research, we extend sequence-based specification to explicitly include time, continuous functions, nondeterminism, and internal events for embedded real-time systems. The enumeration is transformed into an enumeration hybrid automaton that acts as the foundation for an executable model-based design and an algebraic hybrid I/O automaton with valuable theoretical properties. Enumeration is a step-wise problem solving technique that complements model-based design by converting ordinary requirements into precise specifications. The goal is a complete, consistent, and traceably correct design with a basis for automated testing

EVALUATION OF A MODELING AND AUTOMATIC C CODE GENERATION TOOLSET AS AN OPEN SOURCE ALTERNATIVE SOLUTION

International audienceThis paper is focused on the model based design (MBD) approach, more particularly on the automatic C code generation. The goal of our project consists in evaluating how far the toolset called Scilab-Scicos and GeneAuto can be used as the open source alternatives to other solutions