Search results for "racking"

Adaptive Tracking Control of Nonlinear Time-Varying Systems with Unknown Control Coefficients and Unknown Time-Varying Parameters

2019

This paper investigates the tracking control of a class of strict-feedback uncertain nonlinear systems in the presence of unknown signs of control coefficients and unknown time-varying parameters as well as unknown disturbances. A robust adaptive controller and a new decoupled backstepping approach to stability analysis are developed by constructing a new compensation scheme. By introducing a Nussbaum function and a new type of hyperbolic tangent function, the effects of unknown time-varying parameters and unknown control coefficients are effectively compensated. By using the decoupled backstepping technique, it is proved that under the proposed control, all closed-loop states are uniform u…

Tracking control of network distributed systems in presence of variable time delay and loss of information

2006

This paper deals with the control of network distributed systems which has been at the centre of interest in a wide area of research in the last few year. The control of such systems is very difficult because the communication networks inevitably introduce variable time delays and possible lost of samples. In particular, it is proposed an extension of the approach, derived in the contest of the optimal stochastic regulator problem [1], [2], to the remote tracking problem considering a distributed control system in which the signals from the transducers to the controller and from the controller to the actuator are transmitted through a communication network with variable delays and possible …

Non-fragile sliding mode control for flexible air-breathing hypersonic vehicles

2012

The non-fragile sliding mode tracking control design problem for a flexible air-breathing hypersonic vehicles (FAHVs) is investigated in this paper. A linearized model is constructed with respect to a trim point for the nonlinear, dynamically coupled simulation model of the FAHVs with external disturbance, then a reference model is designed and a tracking error model is proposed. An integral sliding surface is designed, and then the non-fragile H ∞ controller design problem for the sliding mode dynamics is discussed. sufficient condition is derived for the existence of such a controller in the presence of unmatched disturbance. A SMC law is derived to guarantee the reachability of the speci…

Skeletons for parallel image processing: an overview of the SKiPPER project

2002

International audience; This paper is a general overview of the SKIPPER project, run at Blaise Pascal University between 1996 and 2002. The main goal of the SKIPPER project was to demonstrate the appli- cability of skeleton-based parallel programming techniques to the fast prototyping of reactive vision applications. This project has produced several versions of a full-fledged integrated pa- rallel programming environment (PPE). These PPEs have been used to implement realistic vi- sion applications, such as road following or vehicle tracking for assisted driving, on embedded parallel platforms embarked on semi-autonomous vehicles. All versions of SKIPPER share a common front-end and reperto…

Author response: Tracking zoonotic pathogens using blood-sucking flies as 'flying syringes'

2017

Observation and Processing of Instantaneous Frequency Variations During Bearing Tests

2020

Laboratory experiments have been performed on medium sized roller bearings with two levels of artificial damage. Recordings of long time series from accelerometers at a wide range of different radial loads and rotation speeds has been performed. Probably due to non-perfect performance of the control systems for the rotational speed or frequency, significant fluctuations were observed at all rotation speeds. The highest relative variation was observed at the lowest rotational speeds. These variations were recorded using a rotary encoder, which allows order tracking of the vibration signal. In real life condition monitoring, tachometers or rotary encoders are not always present, this can be d…

Hulot's Selinunte: digital analysis and virtual reconstruction

2021

Some drawings feature a powerful evocative nature, capable of presenting a truthful vision that can replace, in collective imagination, the actual expression of reality. This is the case of the "restorations" of Selinunte proposed by the French architect Jean-Louis Hulot (Paris 1871 -1959) which still today evoke the splendours of the ancient city. Thanks to his accurate surveys and inspired by the visit to the remains of further ancient cities such as Priene, Tera, Delos, and Pompeii, Hulot proposed in his watercolour drawings a vision of a "living" city, rendered at the height of its architectural and social magnificence. The paper presents a study on digital solutions that combine data f…

From aerial survey to representation and visualization: the Temple G of Selinunte

2022

The paper reports the outputs of a research work focused on the segmentation of meshes generated from aerial photogrammetric survey, aiming at the implementation of a database integrated in a web-based Information System developed with 3D-Hop technology, that uses models as the access point to information data. Segmentation is a relevant topic in cultural heritage documentation, since it is the a pre-requisite for the development of systems that connect information data to 3D models. The chosen case study is the Doric Temple G of Selinunte, an archaeological site in southern Sicily. Temple G, one of the biggest Doric Temples of Magna Graecia, it is today a huge heap of ruins, probably due t…

Hybrid foveated vision system for video surveillance and robotic navigation

2014

The primary goal of this thesis is to elaborate a binocular vision system using two different types of camera. The system studied here is composed of one omnidirectional camera coupled with a PTZ camera. This heterogeneous association of cameras having different characteristics is called a hybrid stereo-vision system. The couple composed of these two cameras combines the advantages given by both of them, that is to say a large field of view and an accurate vision of a particular Region of interest with an adjustable level of details using the zoom. In this thesis, we are presenting multiple contributions in visual tracking using omnidirectional sensors, PTZ camera self calibration, hybrid v…

Image Content Enhancement Through Salient Regions Segmentation for People With Color Vision Deficiencies

2019

Color vision deficiencies affect visual perception of colors and, more generally, color images. Several sciences such as genetics, biology, medicine, and computer vision are involved in studying and analyzing vision deficiencies. As we know from visual saliency findings, human visual system tends to fix some specific points and regions of the image in the first seconds of observation summing up the most important and meaningful parts of the scene. In this article, we provide some studies about human visual system behavior differences between normal and color vision-deficient visual systems. We eye-tracked the human fixations in first 3 seconds of observation of color images to build real f…