Search results for " Compensation."

Hardware-in-the-loop implementation for an active heave compensated drawworks

2012

Published version of an article published in the journal: Central European Journal of Engineering. Also available from the publisher at: http://dx.doi.org/10.2478/s13531-011-0062-1 This paper presents the setup and running of a hardware-in-loop (HIL) simulation for an active heave compensated (AHC) draw-works. A simulation model of the draw-works is executed on a PC to simulate the AHC draw-works with a physical PLC. The PLC (ET200S) is configured with a controller architecture that regulates the motor angular displacement and velocity through actuation of the servo valves. Furthermore, a graphical user interface is developed for operation of the AHC system. The HIL test allowed tuning of t…

The Effect of Friction in Passive and Active Heave Compensators of Crown Block Mounted Compensators

2012

Abstract This paper studies the effects of friction model during passive and active heave compensation of offshore drilling equipment. The main purpose of heave compensation while drilling from vessels or semi-submersible platforms is to maintain the drilling operation unaffected by the wave induced motion. The investigated system is of an existing crown mounted compensator. A model of the system is developed which includes mechanics, hydraulics and pneumatics. The passive heave compensation scheme is described including force equalising hydraulic cylinders. In this paper the detrimental effect of friction on the heave compensation performance in both passive and active heave compensation i…

Offshore Wind Payload Transfer Using Flexible Mobile Crane

2015

This article presents an offshore-simulated loading and unloading of a payload from a floating platform to a fixed structure. The experiments are performed in a dry-lab, where a Stewart platform is used to simulate the motion of the vessel. A hydraulically actuated vehicle loader crane is used to perform the tasks of payload transfer. The crane includes a hydraulic winch where the wire force is measured by a load cell. A mathematical model of the winch is derived and is experimentally verified. The control strategies include a heave compensation and a constant tension mode. A motion reference unit is used to generate the reference motion of the moving platform. Experimental results show the…

A novel current-based approach for very low variation detection of resistive sensors in wheatstone bridge configuration

2014

A Non-Invasive Thermal Drift Compensation Technique Applied to a Spin-Valve Magnetoresistive Current Sensor

2011

A compensation method for the sensitivity drift of a magnetoresistive (MR) Wheatstone bridge current sensor is proposed. The technique was carried out by placing a ruthenium temperature sensor and the MR sensor to be compensated inside a generalized impedance converter circuit (GIC). No internal modification of the sensor bridge arms is required so that the circuit is capable of compensating practical industrial sensors. The method is based on the temperature modulation of the current supplied to the bridge, which improves previous solutions based on constant current compensation. Experimental results are shown using a microfabricated spin-valve MR current sensor. The temperature compensati…

Tool-Point Control for a Redundant Heave Compensated Hydraulic Manipulator

2012

Abstract In this paper, theoretical and experimental implementation of heave compensation on a redundant hydraulically actuated manipulator with 3-dof has been carried out. The redundancy is solved using the pseudo-inverse Jacobian method. Techniques for minimizing velocities and avoiding mechanical joint saturations is implemented in the null space joint motion. Model based feed-forward, combined with a PI-controller handles the velocity control of each joint. A time domain simulation model has been developed, experimentally verified, and used for controller parameter tuning. Model verification and experimental results are obtained while the manipulator is exposed to wave disturbances crea…

El artículo 18 del estatuto de los trabajadores italiano a la luz de las últimas reformas laborales

2015

En las siguientes líneas se realizará un somero repaso sobre las principales las modificaciones de la disciplina italiana de los despidos individuales recogida en el artículo 18 del Estatuto de los Trabajadores italiano, introducidas por las últimas reformas laborales. En ellas se constará el impacto de dichas reformas en el cuadro legislativo de referencia, viéndose reducida la posibilidad de readmisión del trabajador en el caso de despido individual improcedente. Además se harán unos apuntes críticos sobre el concepto de flexsecurity, de cual se destaca una gran inflación en el presente contexto de crisis económica. This paper examines the amendments made to the Italian regulation of indi…

Niobium enhanced europium ion luminescence in hafnia nanocrystals

2018

This work was supported by the UL ISSP grant for Scientific Research Projects for Students and Young Researchers SJZ/2016/15 .

Determinants of Chairman Compensation

2011

This study examines determinants of chairman compensation in a supervisory board setting and, specifically, the relationship between chairman and CEO compensation. Using a sample of publicly listed firms in Sweden, the study indicates that chairman compensation – despite its fixed nature – is reflective of firm performance via a positive relationship to CEO compensation. As CEO compensation is set before chairman compensation, we argue that the chairman may be inclined to conspire with the CEO in earnings management efforts at the expense of monitoring on behalf of investors. Supporting our argument, we find evidence that the gap between chairman and CEO compensation is less at firms where …

CEO Compensation and Risk-Taking: Evidence from Listed European Hotel Firms

2020

This paper examines the relationship between CEO compensation policies and financial performance in the European hotel sector. We analyze CEO cash-, equity- and total-compensation relationships with two accounting-based and two market-based financial performance proxies, including a bi-dimensional proxy formed by stock market return and risk. This bi-dimensional market-based financial performance proxy enables us to take a deep dive into the relationship between CEO compensation policies and firm risk-taking. We then analyze the nature of this relationship by decomposing market-based risk into systematic and idiosyncratic risk, using five alternative asset-pricing factorial models. Our resu…