W. Elmenreich, W. Haidinger, A. Dias, C. Trödhandl, M. Borovicka:
"Final demonstration of smart sensor interface";
Throughout the DSoS (Dependable Systems of Systems) project the design of component-based dependable systems have been studied. Thus, the objective of the DSoS project is to investigate issues related to the integration of components that are existing complete systems in order to generate a new set of dependable services from the resulting system of systems.
Another aspect handled in DSoS project is the notion of time. In contrast to the fact that the real-time aspect is often neglected in theories of computation, a mobile embedded system imposes also hard real-time requirements onto its control system.
Besides of the theoretical work in the project a main contribution has been the evaluation of the elaborated concepts in form of case study implementations. There are two reasons that justify the labor intensive practical work: First, these case studies demonstrate the applicability of the suggested theoretical ideas and second, there is an immense amount on feedback and inspirations that comes from dealing with practical problems.
One major case study of the DSoS project focuses on the integration of linking interfaces (LIFs) that export/import restricted views of component systems by hiding resource and management issues that pertain just to individual component systems. In order to deal with issues of management there will be a need for more than one kind of LIF. For example a LIF that is used to request or accept service from a component system plays a very different role in a composition from a LIF that is used to reconfigure the internal resources used to deliver that service. Another kind of LIF might be used to signal to a component system that it is no longer delivering the (quality of) service that is expected of it or to adjust some internal parameter.
This document presents a case study of a smart sensor (or, in more general terms, a smart transducer) LIF that was developed at the Institut für Technische Informatik during the DSoS project. The application of the developed smart transducer LIF is shown in the implementation of an autonomous mobile robot, the smart car. It is shown how a robust sensor component system can be configured by combining a set of sensors with standard LIFs.
Since a mobile robot interacts with its environment by means of sensors and actuators and such sensors and actuators come with a wide variety of interfaces and data types, ranging from a simple binary signal over pulse-width-modulated signals up to CCD camera output, a mobile robot is a good demonstration of the LIF's capabilities. In the smart car application, we integrated several commercial sensors and actuators, which all have their own specific interfaces. This was done by assigning each sensor respectively actuator a microcontroller unit (MCU), which transforms the measurement of a sensor in a unified form respectively transforms the unified control value in the format required by the actuator. For short, such a combination of a sensor/actuator with a microcontroller unit is called a smart transducer. This case study was chosen, since integrating legacy systems into a real-time system is a challenging task and an autonomous mobile robot requires such a real-time system.
Furthermore the connection of a smart transducer network to a larger real-time system has been examined and demonstrated by implementing a PCMCIA gateway card that provides an appropriate interface to the services of the network.
Created from the Publication Database of the Vienna University of Technology.