Disturbance Suppression in Attitude Control of Raft System Using Air Spring

2012 ◽  
Vol 184-185 ◽  
pp. 155-160
Author(s):  
Zhi Qiang Lv ◽  
Liang Shi ◽  
Ying Long Zhao
Keyword(s):  
Attitude Control ◽  
Technological Problem ◽  
Analysis Model ◽  
Air Spring ◽  
Isolation System ◽  
Load Variation ◽  
Disturbance Suppression ◽  
Set Up

Though air spring greatly improves the isolation efficiency of raft isolation system, the technological problem occurs as how to maintain raft attitude balance. This paper set up an analysis model of raft attitude disturbance, and analyzed the influence of various disturbance sources on raft attitude, including hull rolling, systematic load variation, and air spring leakage. It proposed to control raft attitude through adjusting the pressure of air spring isolator, and then studied the feasibility of this method. The results show that the influence of various disturbance sources could be canceled effectively by adjusting the pressure of air spring isolator, thus maintaining attitude balance.

Attitude Control of Air Spring Isolation System

2013 ◽  
Vol 419 ◽  
pp. 636-641
Author(s):  
Liang Shi ◽  
Ying Long Zhao ◽  
Wen Jun Bo
Keyword(s):  
Control Strategy ◽  
Attitude Control ◽  
Vibration Isolation ◽  
Fault Tolerant ◽  
Technical Difficulty ◽  
Isolation Effect ◽  
Control Parameters ◽  
Air Spring ◽  
Isolation System ◽  
Response Characteristics

Air spring has been increasingly applied in marine raft isolation system to acquire excellent vibration isolation effect. However, it is a key technical difficulty to keep attitude balance for the raft. The response characteristics of raft attitude have been analyzed in detail. The raft attitude controllability condition for air spring leakage fault is discussed. The analyzed conclusion lays a foundation for ascertaining control parameters and designing fault tolerant control strategy.

Field Determination of Fracture Propagation Mode Using Downhole Pressure Data

2015 ◽  
Author(s):  
Ali Daneshy ◽  
Chad Touchet ◽  
Fred Hoffman ◽  
Mike McKown
Keyword(s):  
Propagation Mode ◽  
Fluid Migration ◽  
Pressure Data ◽  
Isolation System ◽  
Fracture Orientation ◽  
Coiled Tubing ◽  
Treatment Data ◽  
Set Up ◽  
Adjacent Fractures ◽  
First Time

Abstract This paper presents the analysis results of 60 single stage fracturing treatments performed in a horizontal well using cemented casing sleeves and a coiled tubing deployed frac isolation system as the completion method. In this carefully set-up and executed treatment, separation between the toe stages was 97 feet, and near the heel it was 55 feet. Pressure data was collected above and below the retrievable plug used for stage isolation. This data was used for analysis of fracturing treatment data which included mode of propagation, completion efficiency, and a rough estimate of fracture orientation. The analysis showed that; There was no interaction between adjacent fractures during five of the sixty fracturing stages. None of these was in the well interval with shorter fracture spacingFracture shadowing occurred during six fracture stages, again none in the shorter spacing intervalMinor cement defects (micro-annuli) caused some fluid migration into the passive segment of the well. This happened in 27 stages. Of these; In eleven cases the cement defects were plugged after a while, causing the migration of fracturing fluid into the passive interval to stop.In sixteen other cases the fluid migration through cement micro-annuli continued during fracturing.During ten stages, defective zone isolation and fluid migration caused a pressure increase of several hundred psi in the passive segment of the well. But this did not result in extension of passive fractures.The volume of migrated slurry due to inadequate zone isolation was mostly a very small fraction of the injected volume.During five stages poor cement quality hampered stage isolation and caused immediate link between adjacent active and passive intervals and extension of passive fractures.The data indicate possible connection between the active and one passive fracture in four stages.Shorter spacing between stages increased the incidents of fluid migration due to poor cement qualityThe fracturing pressure variations during the treatments did not indicate presence of large stress shadowingA rough estimation of fracture orientation indicates that they were likely to be vertical and nearly perpendicular to the wellbore.The fracture growth pattern can best be described as off-balance. To our knowledge, this is the first time existence of direct communication between adjacent fractures has been observed through actual pressure interference data.

Research on Vibration Isolation System Based on Disturbance Observer PID Control Algorithm

2017 ◽  
Vol 865 ◽  
pp. 480-485
Author(s):  
Jian Liang Li ◽  
Xiao Xi Liu ◽  
Shu Qing Li ◽  
Zhi Fei Tao ◽  
Lei Ma
Keyword(s):  
Pid Control ◽  
Disturbance Observer ◽  
Control Algorithm ◽  
Vibration Isolation ◽  
Low Frequency ◽  
Isolation System ◽  
Vibration Isolation System ◽  
Virtual Test ◽  
Set Up ◽  
And Control

The research mainly focuses on the performance of the controllable hypocenter in the low frequency band. The hybrid vibration isolation method based on the disturbance observer PID control algorithm is used to improve the excitation signal quality. Based on the analysis of the structure and working principle of vibration isolator, the physical model and mathematical model are established, and the simulation test of ZK-5VIC virtual test vibration and control system is carried out. The experimental platform of hybrid vibration isolation system with low frequency interference is set up. The experiment of excitation and acquisition of low frequency signal is carried out, which provides the theoretical basis and guarantee for the vibration isolation technology in the low frequency range below 3Hz.

Study on Three-Dimensional Seismic Isolation System for Next Generation Nuclear Power Plant: Independent Cable Reinforced Rolling-Seal Air Spring

2004 ◽  
Author(s):  
Mitsuru Kageyama ◽  
Yoshihiko Hino ◽  
Satoshi Moro
Keyword(s):  
Power Plant ◽  
Nuclear Power ◽  
Seismic Isolation ◽  
Base Isolation ◽  
Three Dimensional ◽  
Outer Diameter ◽  
Next Generation ◽  
Air Spring ◽  
Isolation System ◽  
Rubber Sheet

In Japan, the development of the next generation NPP has been conducted in recent years. In the equipment/piping design of the plant, seismic condition has been required much more mitigate than before. So, the three-dimensional (abbreviation to 3D) seismic isolation system development has also been conducted since 2000. The superlative 3D base isolation system for the entire building was proposed. The system is composed of cable reinforced air springs, rocking arresters and viscous dampers. Dimensions of the air spring applied to the actual power plant are 8 meters in the outer-diameter and 3.5 meters in height. The allowable half strokes are 1.0 meters in horizontal and 0.5 meters in vertical respectively. The maximum supporting weight for a single device is 70 MN. The inner design air pressure is about 1.8MPa. This air spring has a distinguishing feature, which realizes 3D base isolation with a single device, whose natural periods are about 4 seconds in horizontal and about 3 seconds in vertical. In order to verify the 3D performance of this system, several feasibility tests were conducted. Firstly, 3D shaking table tests were conducted. The test specimen is scaled 1/4 of the actual device. The outer diameter and inner air pressure of air spring is 2 meters and 0.164 MPa. Next, a pressure resistant test for the sub cable, textile sheet and rubber sheet, which composed air spring, were conducted as a full scale model test. Then, air permeation test for the rubber sheet was also conducted. As a result, the proposed system was verified that it could be applied to the actual nuclear power plants.

Hydrological Zoning System for Highway Engineering

2015 ◽  
Vol 744-746 ◽  
pp. 1257-1260
Author(s):  
Yu Lan Wang ◽  
Chao Li
Keyword(s):  
Index System ◽  
Research Work ◽  
First Grade ◽  
Analysis Model ◽  
Highway Engineering ◽  
Research Framework ◽  
Intensity Index ◽  
Set Up ◽  
The Relationship ◽  
Slope Runoff

In order to strengthen the normalization of the highway hydrology Zoning research work and improve the efficiency of Zoning, the analysis model of slope runoff intensity index was set up. The provincial highway hydrological Zoning index system was built to fully embody the relationship between highway engineering and hydrological factors. The research framework of provincial highway hydrology Zoning was established. The highway hydrology Zoning research framework and Zoning indices was taken as the guidance to divide Shandong province into 2 first-grade highway hydrological regions and 6 highway hydrological subregions which reflect the overall distribution of the highway hydrological conditions in the research region correctly. The corresponding descriptions were given to introduce the highway engineering characteristics of each partition.

Research on Strengthening Existing Bridges by Widening

2013 ◽  
Vol 639-640 ◽  
pp. 1092-1095
Author(s):  
Guang Hui Wang ◽  
Lian Shen ◽  
Cheng Long Wei
Keyword(s):  
Finite Element ◽  
Bearing Capacity ◽  
Basic Theory ◽  
Parameter Analysis ◽  
New Method ◽  
Analysis Model ◽  
Set Up ◽  
Existing Bridges

This paper aims to put forward a new method of strengthening the existing bridges with narrow decks and low bearing capacity to overcome the high cost and pollution problems in dismantling them. The method, strengthening bridges by built stringers and cross beams, is by widening some parts of a bridge. Based on the basic theory of finite element, we have set up an analysis model of strengthening the bridges by widening, which helps to demonstrate the rationality of this method. Meaningful conclusions have been drawn from the parameter analysis of the rigidity of the new widening stringers, the rigidity of the new cross beams and the relative settlement of the new and the old foundations. This method can be referenced by the reinforcement and maintenance of medium and small bridges.

Dynamics Analysis and Vibration Isolation Design of Shared Foundation on Marine Turbo Generator Set

2013 ◽  
Vol 572 ◽  
pp. 193-196
Author(s):  
Chong Liu ◽  
Chang Hua Qiu ◽  
Lei Gao
Keyword(s):  
High Speed ◽  
Vibration Isolation ◽  
Stable Operation ◽  
Dynamical Response ◽  
Dynamics Analysis ◽  
Analysis Model ◽  
Lumped Mass ◽  
Isolation System ◽  
Vibration Isolation System ◽  
Turbo Generator

Considering the ship's limited space, high speed and miniaturization have been design directions in marine turbo generator set. The shared foundation with steel plate welding is designed to support the marine turbo generator set. Stiffness and dynamic characteristic of the shared foundation will directly affect the stable operation of the turbo generator set. The paper established the dynamics analysis model for the shared frame of marine turbo generator set according to the 'Lumped Mass Method'. Taking account of the frequency-domain analysis operability, the operational modal analysis and dynamical response on foundation were carried out by Virtual Lab. Based on these results; the intensity and location of exciting force were ascertained. And then, we designed the shared foundation vibration isolation system, and analyzed the characteristics of the vibration isolation mounting. The result shows that the vibration isolation system can minimize output force transmissibility and reduce the effect of the marine turbo generator set vibration.

Study on Business Model of Motorway Service Area Based on TOPSIS-Entropy Method

2013 ◽  
Vol 694-697 ◽  
pp. 3381-3384
Author(s):  
Feng Peng ◽  
Bin Zhan
Keyword(s):  
Business Model ◽  
Index System ◽  
Entropy Method ◽  
Service Area ◽  
Entropy Analysis ◽  
Analysis Model ◽  
Set Up

This paper firstly points out the concept of the Motorway Service Area. With the features it included being analyzed, a reasonable index system of Motorway Service Area is being set up. Then the TOPSIS-Entropy analysis model is presented. For this part, entropy method is used for empowering the evaluation indicators of business model, thus the business model is evaluated and sorted. Finally, an example verifies the validity and applicability of the model.

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