Search results for "Displacement"
showing 10 items of 433 documents
A novel correction method for a low cost sensorless control system of IPMSM electrical drives
2008
In this paper a novel correction method for sensorless Field Oriented Control System of Brushless internal Permanent Magnet Electrical Drives is introduced discussed and experimentally validated. The novelty of this control system is the estimation of rotor speed and angular position is based on the back electromotive force space vector determination, without the aid of voltage probes. Actual voltage signals needed for estimation are replaced with the reference ones given by the current controller. This choice obviously introduces an error that have been vanished by means of a new compensating function or with the aid of data coming from experimental tests. Experimental verifications of the…
Definition of performance requirements and test cases for offshore/subsea winch drive systems with digital hydraulic motors
2019
Abstract A subsea crane is normally mounted on a floating vessel and equipped with a winch system. The crane can operate in water down to 3000 m. The vessel tends to move up and down due to waves. This heave motion makes offshore lifting operations challenging. In order to ease the winch operation in rough sea, the winch can be equipped with additional systems like active heave compensation and constant tension. In active heave compensation and constant tension system, both motion and force control of the winch are important. This paper presents a digital displacement winch drive system and gives a description of challenges related to subsea lifting operations. The operation challenges are …
nalysis, Modeling and Simulation of Mechatronic Systems using the Bond Graph Method
2011
The Bond Graph is the proper choice of physical system used for: (i) Modeling which can be applied to systems combining multidisciplinary energy domains, (ii) Analysis to provide a great value proposition for finding the algebraic loops within the system enabling the process of troubleshooting and eliminating the defects by using the proper component(s) to fix the causality conflict even without being acquainted in the proper system, and (iii) Simulation facilitated through derived state space equations from the Bond Graph model is solved using industrial simulation software, such as 20-Sim. The Bond Graph technique is a graphical language of modeling, in which component energy ports are co…
Upper thoracic-spine disc degeneration in patients with cervical pain.
2003
To study the relationship of upper thoracic spine degenerative disc contour changes on MR imaging in patients with neck pain. The relation between upper thoracic and cervical spine degenerative disc disease is not well established.One hundred and fifty-six patients referred with cervical pain were studied. There were 73 women and 77 men with a mean age of 48.6 +/- 14.6 years (range, 19 to 83 years). All MR studies were performed with a large 23-cm FOV covering at least from the body of T4 to the clivus. Discs were coded as normal, protrusion/bulge or extrusion.Degenerative thoracic disc contour changes were observed in 13.4% of patients with cervical pain. T2-3 was the most commonly affecte…
An analytical solution for multilayered beams subjected to ends loads
2014
An alternative model for multilayered beams undergoing axial, shear and bending loads applied at the beam's ends is developed. It is based on a layer-wise kinematics, which inherently fulfills the equilibrium equations at layer level and the interface continuity conditions. This kinematics is suitably expressed by introducing a set of generalized variables representative of the beam midline displacement field, which become the primary variables of the problem governing equations. As a consequence, the proposed beam model exhibits the computational characteristics of an equivalent single layer model and possesses the accuracy of layer-wise beam theories, as well. Closed form solutions for di…
Hybrid materials with nanoscopic anion-binding pockets for the colorimetric sensing of phosphate in water using displacement assays
2008
Mesoporous amino-functionalised solids containing certain dyes have been used as suitable anion hosts in displacement assays for the colorimetric signalling of phosphate in water. Amoros del Toro, Pedro Jose, Pedro.Amoros@uv.es
Modeling of Friction Losses in Offshore Knuckle Boom Crane Winch System
2018
This paper presents a method for friction modeling in a hydraulically actuated multi motor winch system of an offshore knuckle boom crane. The method is based on a combination of a model of the variable displacement axial piston motor based on measurements from the sub supplier, and combined with a model of the remaining friction loss obtained from measurements on the full system.
Fast Axial Scanning in 3D Imaging
2016
We establish the conditions for obtaining fast axial 3D microscopy with constant magnification, invariant resolution, and symmetrical displacement range. We demonstrate that liquid lenses permit the axial scanning free of mechanical movements and vibrations. This allows speeding-up the process and avoiding distortionsin the image of dynamic specimens. Article not available.
Asymptotic observer of the link states of flexible joint robots with motor-side sensing
2015
This paper proposes an approach for observing the link states, i.e. angular position and velocity, of the robotic joints with elasticities, when only the motor-side sensing is available. By separating the state-dependent nonlinearities of the rigid manipulator dynamics a linear sub-model of the elastic joint robot is obtained in an observable state-space form. The standard asymptotic Luenberger state observer is then designed for the given motor position signal which is measured by encoder and rectified from the nonlinear contribution. The configurable poles of observer allow shaping the estimated states dynamics to be fast enough in relation to the actual resonant joint behavior. Therefore…
Elastic waves in random-fibre networks
1997
The propagation of the first displacement maximum of a semi-infinite wavetrain in a two-dimensional random-fibre network is analysed. Model calculations and numerical simulations are used for demonstrating that two qualitatively different wavefront velocities appear in the network. A transient wave, which travels fast and whose amplitude decreases exponentially, dominates the short-time behaviour when the bending stiffness of the fibres is small and the driving frequency is high. This mode can be described by a one-dimensional model. The transient-wave mode propagates even if the bending stiffness of the fibres vanishes, in which case the normal sound velocity is zero. The usual, and slower…