Search results for " Mach"

Robust adaptive backstepping control design for a Nonlinear Hydraulic-Mechanical System

2009

The complex dynamics that characterize hydraulic systems make it difficult for the control design to achieve prescribed goals in an efficient manner. In this paper, we present the design and analysis of a robust nonlinear controller for a Nonlinear Hydraulic-Mechanical (NHM) System. The system consists of an electrohydraulic servo valve and two hydraulic cylinders. Specifically, by considering a part of the dynamics of the NHM system as a norm-bounded uncertainty, two adaptive controllers are developed based on the backstepping technique that ensure the tracking error signals asymptotically converge to zero despite the uncertainties in the system according to the Barbalat lemma. The resulti…

Coherency identification and oscillation damping effects of PSS in interconnected power system: A comparative analysis approach

2016

This paper analyzes four different test systems for defining coherent generators in the multi machine power systems based on the Eigen properties of the linearized model of the inter connected power system. The disruption is measured to be dispersed in the network by smearing small signal disturbance in each case. For finding the coherent areas and their tolerances in the inter-connected power system, no generator buses are allocated to each cluster of coherent generator using similar coherency recognition methods. The technique is assessed with four test schemes, and coherent generators and zones are acquired for diverse functioning points to render a more precise consortium approach, whic…

How is the problem solving process of a paper machine in Indonesia progressing?

2002

A portable instrument for the location and identification of defects generating PD

2011

A portable instrument based on an antenna probe and suitable for partial discharge detection, have been characterized through both laboratory and on-site experiments carried out on coils and stator windings of ac rotating machines. The antenna probe allows the capture of electromagnetic waves in a bandwidth of 0.1–100 MHz. Pulse signals and ac supply voltage reference are obtained by means of high-pass and low-pass filters, respectively, so avoiding the need of a direct connection with the objects under test. By this way, real-time phase resolved partial discharge patterns can be derived. Results of a comparison of the diagnostic information provided by PD patterns due to conducted and irra…

Conclusions from the Evaluation of Virtual Machine Based High Resolution Display Wall System

2016

There are several approaches to the construction of large scale high resolution display walls depending on the required use case. Some require support of 3D acceleration APIs like OpenGL, some require stereoscopic projection. Others simply require a surface with a very high display resolution. The authors of this paper have developed a virtual machine based high resolution display wall architecture that works for all planar projection use cases and does not require a custom integration. The software that generates the presented content is executed in a virtual machine thus no specific APIs other than those of the virtualized OS are required. Any software that is able to run under a given OS…

An electromagnetic generator for MAGLEV transportation systems

2015

The fundamental idea of this paper is to use the distribution theory to analyze linear generators in order to include in the mathematical model both ideal a non ideal features. This paper shows how the use of distribution theory can be used in order to establish a mathematical model able to describe both the ordinary working condition of a linear generator for MAGLEV systems as well the role of the unavoidable irregularities and non-ideal features.

Fatigue methodology for life predictions for the wheel-rail contact area in large offshore turret bearings

2016

The present report presents a fatigue life prediction method for large roller bearings applied in the turret turn table for large loading buoy units. The contact points between wheel and rail in these bearings are subjected to a multi-axial fluctuating stress situation and both surface wear and fatigue cracking may occur. A methodology based on the Dang Van fatigue criterion is adopted. The criterion is based on an equivalent stress defined as a combination of the fluctuation of the shear stress from its mean value at a critical plane and the associated hydrostatic stress at the given time. The present work is supporting the theoretical model by extensive laboratory testing. Both full scale…

Behaviour of a speargun with a novel muzzle - Comportamento di un fucile subacqueo con testata innovativa

2013

The paper presents the results of a numerical and experimental investigation performed on a barrel of a speargun equipped with two kinds of muzzle. In particular, a standard muzzle for speargun (having an elastic propulsion) has been compared with an innovative one called ‘roller’. This new muzzle is equipped with two rollers and special bands. The rubber bands, fixed at the lower side of the barrel, run through the rollers and are engaged in suitable seats of the shaft. These bands are, therefore, longer than the traditional ones and, consequently, with equal force applied by the diver, the roller speargun has a longer range. Thanks to the particular geometry of the new muzzle, one of the …

A cogging torque minimization procedure for IPMSMs based on different laminate geometry

2016

This paper presents a possible minimization procedure of the cogging torque generated by an IPMSM (Interior Permanent Magnet Synchronous Machine) with a progressive modification of a basic geometrical structure of rotor laminates. More in detail, an IPMSM model is analyzed by using a Finite Element Method (FEM) approach. Then, other IPMSM models, which are obtained by modifying the geometry of the IPMSM rotor laminates and by maintaining the same stator configuration, are proposed and discussed. From the obtained simulation results, the cogging torque components for each structure are determined by means of FEM and compared to each other. From this comparison, it can be stated that the cogg…

A two-stage fault detection and classification for electric pitch drives in offshore wind farms using support vector machine

2017

This article presents a two-stage fault detection and classification scheme, for induction motor drives in wind turbine pitch systems. The presented approach is suitable for application in offshore wind farms. The adopted strategy utilizes three phase motor current sensing at the pitch drives for fault detection and only when a fault is detected at this stage, features extracted from the current signals are transmitted to a central support vector machine classifier. The proposed method is validated in a laboratory setup of the pitch drive.