Filtyp
Grafchart is a graphical programming language for sequential control applications. It exists in two versions: the basic version (BV) and the high-level version (HLV). The currently used Grafchart tool, JGrafchart, only supports BV. To enable further research on HLV, it must be supported by JGrafchart. Since HLV is a superset of BV it is desirable to add it as an extension to the current implementa
Guaranteeing stability of control applications in embedded systems, or cyber-physical systems, is perhaps the alpha and omega of implementing such applications. However, as opposed to the classical real-time systems where often the acceptance criterion is meeting the deadline, control applications do not primarily enforce hard deadlines. In the case of control applications, stability is considered
Time-triggered periodic control implementations are over provisioned for many execution scenarios in which the states of the controlled plants are close to equilibrium. To address this inefficient use of computation resources, researchers have proposed self-triggered control approaches in which the control task computes its execution deadline at runtime based on the state and dynamical properties
The problem to minimize power losses in an electrical network subject to voltage and power constraints is in general hard to solve. However, it has recently been discovered that semidefinite programming relaxations in many cases enable exact computation of the global optimum. Here we point out a fundamental reason for the successful relaxations, namely that the passive network components give rise
A correct design of controllers must necessarily account for the schedule of the controller task over the processor. Existing design techniques are based on the assumption that there is no delay, or the delay is constant over time. However, in practice, almost all controllers have time-varying delay, hence invalidating this assumption. In this paper, we introduce a period design policy, in which t
Joint wheel-slip and vehicle-motion estimation is considered, based on measurements from wheel encoders, an inertial measurement unit, and a global positioning system (GPS). The proposed strategy effectively employs the Rao-Blackwellized particle-filtering framework using a kinematic model. Key vari- ables in active safety systems, such as longitudinal velocity, roll angle, and wheel slip for all
We present a framework for the solution of control and estimation problems under a signal-to-noise (SNR) ratio constraint. The framework can be used to design optimal linear controllers, based on output feedback, with two degrees of freedom: One part of the controller is placed before the communication channel and represents sensing and encoding operations. The other part represents decoding and i
A general framework for the study of robust synchronisation in large-scale networks is provided. Agents are represented as a common nominal linear time-invariant (LTI) single-input-single-output (SISO) system with simple poles on the imaginary axis, subject to LTI SISO stable multiplicative perturbations. The agents exchange information in order to achieve output-synchronisation, namely steer thei
This paper presents a scheme to construct distributed observers for a system consisting of agents interconnected in a graph structure. The scheme is an iterative procedure to improve the observers with respect to global performance. It is modular in the sense that each agent iterates using only local model information. As a consequence, the complexity of the scheme scales linearly with the size of
In production industry today a lot of engineering time is required to develop and maintain control applications. One part of the control applications are the state machines which typically are written in Grafcet/SFC. Several efforts have been made to extend Grafcet/SFC to achieve more effective and convenient development, e.g. by introducing hierarchical structuring, reusable sub-state machines, a
Parallel robots are generally said to be more accurate and have a smaller workspace compared to serial robots. With the Gantry-Tau robot, a parallel robot with relatively large workspace was presented. This article examines the end-effector positioning accuracy of the Gantry-Tau robot. End-effector positioning errors arising from joint positioning or modeling errors are studied. A geometric approa
A three bit second order delta sigma modulator for audio applications implemented in 130nm CMOS technology is presented. The modulator features two integrators, a flash quantizer and two current steering DACs. In order to minimize the effect of delays in the DACs, excessive loop delay (ELD) compensation is utilized. Using an oversampling ratio (OSR) of 80, the design consumes 2.8mW and achieves a
In this paper we present an audio synthesizer that creates audio signals, intended to be reproduced as sound by a loudspeaker. This paper details the design, implementation and verification of an analog, subtractive audio synthesizer. The synthesizer produces a variety of waveforms spanning approximately 3 octaves. The frequency is controlled by an external voltage and the harmonic content is regu
This thesis addresses problems which require low-rank solutions under convex constraints. In particular, the focus lies on model reduction of positive systems, as well as finite dimensional optimization problems that are convex, apart from a low-rank constraint. Traditional model reduction techniques try to minimize the error between the original and the reduced system. Typically, the resulting re
We examine the capacity of artificial biomolecular networks to respond to perturbations with structurally signed steady-state changes. We consider network architectures designed to balance their output production as a function of downstream demand: the species producing the output, called a source, up- or down-regulates its production rate as a function of the demand. Using an exact algorithm we s
The clinical success of targeted cancer therapies is limited by the emergence of drug resistance often due to pre-existing tumor genetic heterogeneity and acquired, therapy-induced resistance. Targeted therapies have varied success in addressing metastatic disease, due to their ability to penetrate certain physiological compartments. This paper considers an evolutionary cancer model that incorpora
