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Reading and writing is modelled in CSP using actions containing the symbols ? and !. These reading and writing actions are synchronous and there is a oneto-one relationship between occurrences of pairs of these actions. It is cumbersome to ease the restriction of synchronous execution of the read and write actions. For this reason we introduce the half-asynchronous parallel operator that acts on actions containing the symbols ¿ and ¡ and study the impact on a Vertex Removing Synchronised Product.

Modern embedded systems are designed for multiple and increasingly demanding tasks. Complex concurrent software is required by multi-task automated service robotics for implementing their challenging (control) algorithms. TERRA is a communicating Sequential Processes (CSP) algebra-based Eclipse graphical modelling tool suite which is capable of C++ code generation. It is designed to ease tedious and error-prone concurrent software development for robotics. However, sufficient simulation and visualization supports are not provided yet in TERRA. A hybrid simulation approach is proposed in this paper to provide simulation capabilities for the TERRA tool suite with respect to the Cyber-Physical Systems (CPS) co-design. Moreover, a visualization for the simulation is designed as well to provide animation facilities which enable users to visually trace simulated execution flows. Finally, we use an example to test the hybrid simulation approach as well as visualization facilities. The simulation approach is shown to be sufficient and the visualization works as intended.

Software that is used to control machines and robots must be predictable and reliable. Model-Driven Design (MDD) techniques are used to comply with both the technical and business needs. This paper introduces a CSP meta-model that is suitable for these MDD techniques. The meta-model describes the structure of CSP models that are designed; using this meta-model it is possible to use all regular CSP constructs when constructing a CSP model. The paper also presents a new tool suite, called TERRA, based on Eclipse and its frameworks. TERRA contains a graphical CSP model editor (using the new CSP meta-model), model validation tools and code generation tools. The model validation tools check whether the model conforms to the meta-model definition as well as to additional rules. Models without any validation problems result in proper code generation, otherwise the developer needs to address the found problems to be sure code generation will succeed. The code generation tools are able to generate CSPm code that is readable by FDR and to generate C++/LUNA code that is executable on embedded targets. The meta-model and the TERRA tool suite are tested by designing CSP models for several of our laboratory setups. The generated C++/LUNA code for the laboratory setups is able to control them as expected. Additionally, the paper contains an example model containing all supported CSP constructs to show the CSPm code generation results. So it can be concluded that the meta-model and TERRA are usable for these kind of tasks.

Timed CSP can be used to model and analyse real-time and concurrent behaviour of embedded control systems. Practical CSP implementations combine the CSP model of a real-time control system with prioritized scheduling to achieve efficient and orderly use of limited resources. Schedulability analysis of a timed CSP model of a system with respect to a scheduling scheme and a particular execution platform is important to ensure that the system design satisfies its timing requirements. In this paper, we propose a framework to analyse schedulability of CSP-based designs for non-preemptive fixed-priority multiprocessor scheduling. The framework is based on the PAT model checker and the analysis is done with dense-time model checking on timed CSP models. We also provide a schedulability analysis workflow to construct and analyse, using the proposed framework, a timed CSP model with scheduling from an initial untimed CSP model without scheduling. We demonstrate our schedulability analysis workflow on a case study of control software design for a mobile robot. The proposed approach provides non-pessimistic schedulability results.