Nicolae Marian

Design models for reusable and reconfigurable state machines

The widespread use of embedded systems mandates a rigorous engineering approach towards embedded software development, i.e. model-based design of embedded software. The paper presents design models of reusable and reconfigurable state machines that have been conceived in the context of the COMDES framework and in particular – the State Logic Controller and the Hybrid State Logic Controller, whose principles of operation are presented in the paper. The latter has been instrumental in developing a reconfigurable executable component, i.e. a function block of class State Machine, which can be used to implement a broad range of embedded applications such as sequential, continuous and hybrid control systems, as well as complex systems specified with hierarchical and concurrent state machines.

A formal component framework for distributed embedded systems

The widespread use of embedded systems mandates the development of industrial software design methods based on formal models (frameworks) and prefabricated components. This paper presents a formal specification of the COMDES framework, focusing on the main architectural issues and the specific line of reasoning that was followed while developing a hierarchy of executable models describing relevant aspects of system structure and behaviour. The above framework has been used to systematically define a hierarchy of reusable and reconfigurable components – simple and composite function blocks, reconfigurable state machines and function units – implementing the executable models presented in the paper.

Component-Based design of embedded software: an analysis of design issues

Widespread use of embedded systems mandates the use of industrial production methods featuring model-based design and repositories of prefabricated software components. The main problem that has to be addressed in this context is to systematically develop a software architecture (framework) for embedded applications, taking into account the true nature of embedded systems, which are predominantly real-time control and monitoring systems. There are a great number of design issues and unresolved problems with existing architectures, which have to be carefully analyzed in order to develop a viable component-based design method for embedded applications. Such an analysis is presented in this paper, which focuses on a number of key issues: specification of system structure; specification of system behaviour; component scheduling and execution; program generation vs. system configuration. The analysis has been used to formulate the guidelines used to develop COMDES – a software framework for distributed embedded applications.

Component-based analysis of embedded control applications

The widespread use of embedded systems requires the creation of industrial software technology that will make it possible to engineer systems being correct by construction. That can be achieved through the use of validated (trusted) components, verification of design models, and automatic configuration of applications from validated design models and trusted components. This design philosophy has been instrumental for developing COMDES—a component-based framework for distributed embedded control systems. A COMDES application is conceived as a network of embedded actors that are configured from instances of reusable, executable components—function blocks (FBs). System actors operate in accordance with a timed multitasking model of computation, whereby I/O signals are exchanged with the controlled plant at precisely specified time instants, resulting in the elimination of I/O jitter. The paper presents an analysis technique that can be used to validate COMDES design models in SIMULINK. It is based on a transformation of the COMDES design model into a SIMULINK analysis model, which preserves the functional and timing behaviour of the application. This technique has been employed to develop a feasible (light-weight) analysis method based on runtime observers. The latter are conceived as special-purpose actors running in parallel with the application actors, while checking system properties specified in Linear Temporal Logic. Observers are configured from reusable FBs that can be exported to SIMULINK in the same way as application components, making it possible to analyze system properties via simulation. The discussion is illustrated with an industrial case study—a Medical Ventilator Control System, which has been used to validate the developed design and analysis methods.

Development of a Tactile Sensor Array

Flexible grasping robots are needed for enabling automated, profitable and competitive production of small batch sizes including complex handling processes of often fragile objects. This development will create new conditions for value-adding activities in the production of the future world. The paper describes the related research work we have developed for sensor design, exploration and control for a robot gripping system, in order to analyze normal forces applied on the tactile pixels for gripping force control and generate tactile images for gripping positioning and object recognition. Section 1 gives an introduction of principles and technologies in tactile sensing for robot grippers. Section 2 presents the sensor cell (taxel) and array design and characterization. Section 3 introduces object recognition and shape analysis ideas showing a few preliminary examples, where geometrical features of small objects are identified. Slip detection in order to define optimum grasp pressure is addressed in section 4. The paper will conclude by addressing future ideas about how to judge or forecast a good grasp quality from sensory information.