Shared-Control for a UAV Operating in the 3D Space

This paper presents a shared-control scheme for a UAV moving in a 3D space while its feasible Cartesian position set is defined by a group of linear inequalities. A hysteresis switch is used to combine the human input and the feedback control input based on the definitions of a safe set, a hysteresis set and a “dangerous” set. Case studies given in the paper show the effectiveness of the shared-control algorithm

Effect of vegetation on sound fields in idealised urban open spaces

Noise pollution is a major environmental problem within the EU and during the last years vegetation was examined for its benefits in increasing health and well-being of citizens from different viewpoints, including noise control and soundscape enhancement. This work focuses on numerical simulations to investigate the effectiveness of vegetation for controlling sound fields, especially in terms of the abatement of traffic noise. Two idealised urban squares were studied, one rectangular and one octagonal. Three plant types, climbing plants (ivy), living green walls with soil substrate and plants in pots (nephrolepis exaltata), were used in this investigation, based on their measured properties in laboratory, and four aspects of the use of vegetation were evaluated: effect of the amount of vegetation, effect of changing in the scattering coefficient of vegetation, effect of vegetation in different receiver positions and effect of vegetation on different groups of receivers. Parametric studies on the determination of a line source and on the definition of sound power levels referred to traffic noise were also developed. Three simulation tools were used, namely CATT-Acoustic®, CRR (Combined Ray-tracing and Radiosity) and Odeon

Shared-control for the kinematic model of a rear-wheel drive car

This paper presents a shared-control algorithm for the kinematic model of a rear-wheel drive car, for which the set of feasible Cartesian positions is defined by a group of linear inequalities. The shared-control scheme is based on a hysteresis switch and its properties are established by a Lyapunov-like analysis. Simple numerical examples demonstrate the effectiveness of the shared-control law

Output-Feedback Shared-Control for Fully Actuated Linear Mechanical Systems

This paper presents an output feedback shared-control algorithm for fully-actuated, linear, mechanical systems. The feasible configurations of the system are described by a group of linear inequalities which characterize a convex admissible set. The properties of the shared-control algorithm are established with a Lyapunov-like analysis. Simple numerical examples demonstrate the effectiveness of the strategy

BCI-assisted training for upper limb motor rehabilitation: estimation of effects on individual brain connectivity and motor functions

The aim of the study is to quantify individual changes in scalp connectivity patterns associated to the affected hand movement in stroke patients after a 1-month training based on BCIsupported motor imagery to improve upper limb motor recovery. To perform the statistical evaluation between pre- and post-training conditions at the single subject level, a resampling approach was applied to EEG datasets acquired from 12 stroke patients during the execution of a motor task with the stroke affected hand before and after the rehabilitative intervention. Significant patterns of the network reinforced after the training were extracted and a significant correlation was found between indices related to the reinforced pattern and the clinical outcome indicated by clinical scales

Differences in soundscape appreciation of walking sounds from different footpath materials in urban parks

The perception of the acoustic environment, namely the soundscape, in urban parks has attracted increasing attention. There is a growing belief that the management of the acoustic environment of urban parks should be addressed within a broader soundscape methodology rather than a merely noise control one. One of the most frequent sound sources in urban parks is walking sound; however walking sound perception so far has mainly been investigated for indoor environments. This paper aims to investigate the overall effect of walking sounds from different walked-on materials on people's soundscape, combined with other non-acoustical factors. Moreover, this research investigates how perception varies when the walking sound is self-produced or simply listened. To this purpose, two laboratory experiments in Italy and UK were carried out with four walked-on materials that were considered to be possible design solutions for the footpaths of urban parks: grass, wood, stone and gravel. Results showed a significant effect of materials on perceived noise annoyance and soundscape quality, as well as a partial influence of other nonacoustical factor. Considering the individual responses for the four selected materials, gravel was associated to the worst soundscape quality (M = 38.42) while grass to the best one (M = 65.05). While a group effect (Italian and UK samples) was observed for perceived noise annoyance corresponding to the materials, no significant group effect was found for soundscape evaluation. Eventually, people simply listening to the walking sounds resulted to be less tolerant towards them, with respect to people who self-produced the sounds by walking

Set-point regulation of an anaerobic digestion process with bounded output feedback

Published versio

Sound perception of different materials for the footpaths of urban parks

Over the years the environmental potential of urban parks has attracted increasingly attention. In order to preserve their positive influence for communities, the sonic environment perception (soundscape) must be considered too. Urban parks’ sonic environment is influenced by attenders moving around; indeed, walking sounds have very high occurrence in such contexts. However, studies investigating both walking sounds and soundscape are limited. This study investigates the influence of different footpath materials on the sonic perception. A laboratory listening experiment was carried out with four walked-on materials: grass, wood, stone and gravel. Preliminary results show a significant material effect on soundscape perception

Energy-maximising moment-based constrained optimal control of ocean wave energy farms

Successful commercialisation of wave energy technology inherently incorporates the concept of an array of wave energy converters (WECs). These devices, which constantly interact via hydrodynamic effects, require optimised control that can guarantee maximum energy extraction from incoming ocean waves while ensuring, at the same time, that any physical limitations associated with device and actuator systems are being consistently respected. This paper presents a moment-based energy-maximising optimal control framework for WECs arrays subject to state and input constraints. The authors develop a framework under which the objective function (and system variables) can be mapped to a finite-dimensional tractable quadratic program (QP), which can be efficiently solved using state-of-the-art solvers. Moreover, the authors show that this QP is always concave, i.e. existence and uniqueness of a globally optimal solution is guaranteed under this moment-based framework. The performance of the proposed strategy is demonstrated through a case study, where (state and input constrained) energy-maximisation for a WEC farm composed of CorPower-like WEC devices is considered

Homogeneous Approximation, Recursive Observer Design, and Output Feedback

We introduce two new tools that can be useful in nonlinear observer and output feedback design. The first one is a simple extension of the notion of homogeneous approximation to make it valid both at the origin and at infinity (homogeneity in the bi-limit). Exploiting this extension, we give several results concerning stability and robustness for a homogeneous in the bi-limit vector field. The second tool is a new recursive observer design procedure for a chain of integrator. Combining these two tools, we propose a new global asymptotic stabilization result by output feedback for feedback and feedforward systems