Search results

In the tropical moist semi-deciduous forests of West Africa, soil catenas with extremely gravel-rich soil horizons at the summits and upper slopes and largely gravel-free profiles at the lower slope are common. Previous investigations have suggested that these gravel layers are the result of macro-invertebrates mining of fine-grained soil material from the subsoil leaving behind the gravel, to bu

Here, we propose a new procedure for output feedback design for systems with nonlinearities satisfying quadratic constraints. It provides an alternative for the classical observer-based design and relies on transformation of the closed-loop system with a dynamic controller of particular structure into a special block form. Asymptotic stability is shown using Lyapunov theory with strictly positive

In this research, it is shown that robot joint torques can be used to recognize contact force transients induced during robotic manipulation, thus detecting when a task is completed. The approach does not assume any external sensor, which is a benefit compared to the state of the art. The joint torque data are used as input to a recurrent neural network (RNN), and the output of the RNN indicates w

In this paper, it is shown that temporally coupled dynamical movement primitives (DMPs), used to model and execute robot movements, are globally exponentially stable. It follows that DMPs converge to their goal configurations, which is necessary to accomplish most tasks. The convergence is proven mathematically, and then verified in simulations as well as experimentally on an industrial robot.

This report describes a method to estimate the video bandwidth for IP cameras using the H.264 standard. The precise determination of bandwidth allows us to model the network access as a scheduling problem and/or estimate the amount of data that would traverse it during different periods. The paper is written to be as didactic as possible and presents a set of experiments, conducted in an industria

A new and freely available model-based PID design tool for Matlab is introduced. It can be used to solve Maximal Integral Gain Optimization (MIGO) and (load) Integral Absolute Error (IAE) problems. Robustness is ensured through H-inf constraints on the closed-loop transfer functions. A Youla parameter (Q design) method for comparison with the optimal linear time-invariant (LTI) controller for the

This paper highlights recent development of fuel cell hybrid vehicle (FCHV) models using the Fuel Cell Library (FCL), the Vehicle Dynamics Library (VDL), and Electrification Library (EL) from Modelon. A flexible model architecture is implemented to support physical modeling of such large scale, multi-domain vehicle system. The top-level model consists of a hydrogen fuel cell subsystem with detaile

Aerosol-cloud interactions (ACI) constitute the single largest uncertainty in anthropogenic radiative forcing. To reduce the uncertainties and gain more confidence in the simulation of ACI, models need to be evaluated against observations, in particular against measurements of cloud condensation nuclei (CCN). Here we present a data set - ready to be used for model validation - of long-term observa

When local control strategies are used to arrange a platoon into a string like formation, there is mounting evidence that a poorly regulated accordion like motion will emerge. In this paper we prove that this is an inevitable consequence of using local distance measurements to design the control. More specifically we demonstrate that no controller, irrespective of its dynamical complexity, sparsit

The passivity approach to the design of large networks is based on preserving the passivity property under different types of interconnection: parallel and negative feedback. Since the passivity property implies stability, this allows large and topologically complex networks to be constructed on the basis of simple local rules without the need for global stability analysis. In this paper we charac

Implementing frequency response using grid-connected inverters is one of the popular proposed alternatives to mitigate the dynamic degradation experienced in low inertia power systems. However, such solution faces several challenges as inverters do not intrinsically possess the natural response to power fluctuations that synchronous generators have. Thus, to synthetically generate this response, i

A method for designing a set of controllers to robustly stabilise a network of linear systems is presented. The method allows the design of each controller to be posed as a loopshaping problem. Critically each loopshaping problem requires only local knowledge of the overall system model to formulate, and may be solved separately. Furthermore the approach is inherently scalable, as any local change

In this paper two novel autotuners are compared with two industrially available ones. The aim is to see if the research frontline can improve the industry standard of today. Experiments are made on three laboratory processes with different characteristics. Two lag-dominated processes of which one is a level control problem with fast dynamics, and one a temperature control problem with slow dynamic

The MEthane Remote sensing Lidar missioN (MERLIN) aims at demonstrating the spaceborne active measurement of atmospheric methane, a potent greenhouse gas, based on an Integrated Path Differential Absorption (IPDA) nadir-viewing LIght Detecting and Ranging (Lidar) instrument. MERLIN is a joint French and German space mission, with a launch currently scheduled for the timeframe 2021/22. The German S

When changes happen to big data analytics (BDA) applications in the Cloud at runtime, the affected BDA applications have to be re-deployed to accommodate the changes. Deciding the most suitable deployment is critical and complicated. Although there have been various research studies working on BDA application management, autonomic deployment decision making is still an open research issue. This pa

In this paper we study the problem of automatically generatingpolynomial solvers for minimal problems. The maincontribution is a new method for finding small eliminationtemplates by making use of the syzygies (i.e. the polynomialrelations) that exist between the original equations. Usingthese syzygies we can essentially parameterize the setof possible elimination templates.We evaluate our method o

The problem of low-rank approximation with convex constraints, which appears in data analysis, system identification, model order reduction, low-order controller design and low-complexity modelling is considered. Given a matrix, the objective is to find a low-rank approximation that meets rank and convex constraints, while minimizing the distance to the matrix in the squared Frobenius norm. In man

The problem of planning a trajectory for robots starting in an initial state and reaching a final state in a desired interval of time is tackled. We propose an approach based on model predictive control to solve the problem of point-to-point trajectory generation for a given final time. We discuss various choices of models, objective functions, and constraints for generating trajectories to transf

The Large Gain Theorem is an input-output stability result with intriguing applications in the field of control systems. This paper aims to increase understanding and appreciation of the Large Gain Theorem by presenting an interpretation of it for linear time-invariant systems using the well-known Nyquist stability criterion and illustrative examples of its use. The Large Gain Theorem is complemen