Component-based techniques revolve around composable, reusable software objects that shield the application level software from the details of the hardware and lowlevel software implementation and vice versa. Components provide many benefits that have led to their wide adoption in software and middleware developed for embedded systems: They are well-defined entities that can be replaced without affecting the rest of the systems, they can be developed and tested separately and integrated later, and they are reusable. Clearly such features are important for the design of large-scale complex systems more generally, beyond software architectures. We propose the use of a component approach to address embedded control problems. We outline a general componentbased framework to embedded control and show how it can be instantiated in specific problems that arise in the control over/of sensor networks. Building on the middleware component framework developed under the European project RUNES, we develop a number of control-oriented components necessary for the implementation of control applications and design their integration. The paper provides the overview of the approach, discusses a real life application where the approach has been tested and outlines a number of specific control problems that arise in this application.

VL - 13 N1 -Invited paper

ER - TY - CONF T1 - An experimental study of exploiting multipath fading for robot communications T2 - Proceedings of Robotics: Science and Systems Y1 - 2007 A1 - M. Lindhè A1 - K. H. Johansson A1 - A. Bicchi KW - Robotics AB -A simple approach for mobile robots to exploit multipath fading in order to improve received radio signal strength (RSS), is presented. The strategy is to sample the RSS at discrete points, without deviating too far from the desired position. We first solve the problem of how many samples are needed for given communications performance and how they should be spaced. Second, we propose a circular and a grid trajectory for sampling and give lower bounds on how many samples they will yield. Third, we estimate the parameters of our strategy from measurements. Finally we demonstrate the validity of our analysis through experiments.

JF - Proceedings of Robotics: Science and Systems CY - Atlanta, GA, USA ER - TY - CONF T1 - On the Design and Control of Wireless Networked Embedded Systems T2 - Int. Conf. on Computer Aided Control System Design - CACSD'06 Y1 - 2006 A1 - K -E Arzén A1 - A. Bicchi A1 - S. Hailes A1 - K. H. Johansson A1 - J. Lygeros KW - Embedded Control KW - Robotics AB -Wireless networked embedded systems are becoming increasingly important in a wide area of technical fields. In this tutorial paper we present recent results on design and control of these systems developed within the project Reconfigurable Ubiquitous Networked Embedded Systems (RUNES), which is an European Integrated Project with the aim to control complexity in networked embedded systems by developing robust and scalable middleware systems. New components for control under varying network conditions are discussed for the RUNES architecture. The complexity of the closed-loop system is increased due to the coupling with the disturbances introduced by the communication system. The network may introduce additional delays, jitter, data rate limitations, packet losses etc. Experimental work on integration test beds that demonstrates these results is shown together with motivating links to the RUNES disaster relief tunnel scenario.

JF - Int. Conf. on Computer Aided Control System Design - CACSD'06 PB - IEEE ER - TY - CONF T1 - Control of Distributed Embedded Systems in the Presence of Unknown–but–Bounded Noise T2 - Proc. IEEE Int. Conf. on Decision and Control Y1 - 2004 A1 - B. Picasso A1 - L. Palopoli A1 - A. Bicchi A1 - K. H. Johansson KW - Embedded Control KW - Robotics AB -In this paper we consider the problem of controlling multiple scalar systems through a limited capacity shared channel. Each system is affected by process noise and can be controlled byactuators with values in a {\em fixed}inite set. The control objective is to bound the evolution of the systems in specified sets (controlled invariance). Our goal is to find an optimal allocation of the shared communication resource to the different control activities and to identify correct choices for the design parameters. The paper provides fundamental conceptual tools to attack the design problem in the formal framework of an optimization problem. Namely, we give a feasibility criterion to decide whether a set of design parameters conforms with a control specification (i.e., with the controlled invariance of a specified set for each system). Moreover, we offer the explicit computation of the minimum bit rate necessary for the controlled invariance of a set, which is of utmost importance for solving the optimization problem.

JF - Proc. IEEE Int. Conf. on Decision and Control ER - TY - CONF T1 - Quantised Control in Distributed Embedded Systems. T2 - Proc. 16th Int. Symp. on Mathematical Theory of Networks and Systems Y1 - 2004 A1 - A. Bicchi A1 - K. H. Johansson A1 - L. Palopoli A1 - B. Picasso KW - Embedded Control KW - Robotics AB -Traditional control design is based on ideal assumptions concerning the amount, type and accuracy of the information flow that can be circulated across the controller. Unfortunately, real implementation platforms exhibit non-idealities that may substantially invalidate such assumptions. As a result, the systems closed-loop performance can be severely affected and sometimes stability itself is jeopardised. These problems show up with particular strength when multiple feedback loops share a limited pool of computation and communication resources. In this case the designer is confronted with the challenging task of choosing at the same time the control law and the optimal allocation policy for the shared resources (control algortihm/system architecture co-design).

JF - Proc. 16th Int. Symp. on Mathematical Theory of Networks and Systems ER -