On the Use of Main Hoist Tension Measurement for Feed Forward in DP Systems During Offshore Installations

2010 ◽  
Author(s):  
Olaf Waals
Keyword(s):  
Kalman Filter ◽  
Horizontal Plane ◽  
Model Tests ◽  
Feed Forward ◽  
Offshore Installations ◽  
Heavy Lift ◽  
The Difference ◽  
Predictor Model ◽  
Main Hoist ◽  
Weight Shifts

DP systems are nowadays widely used on installation and crane vessels. In recent years a few cases have been reported where the DP system becomes instable during the installation. Two main reasons can cause these instabilities. First of all the predictor model that is used in the Kalman filter has to accommodate the difference in the mass that occurs when its weight shifts from the barge to the crane. The second and more important reason is the tension in the main hoist wire which acts as an additional spring in the horizontal plane. Some DP-systems have a special heavy lift mode, which is activated when instabilities occur. The present paper describes a different method that uses the actual tension measurement in the hoist wire to enhance the DP system and correct for the additional forces in the horizontal plane due to the hoisting wire. The proposed method is investigated in a series of model tests and results are presented. It is shown that the hoist feed forward improves the overall behavior significantly.

Resistance Tests of an Articulated Pusher Barge System in Deep and Shallow Water

2021 ◽  
Author(s):  
Li Zhang ◽  
Lei Xing ◽  
Mingyu Dong ◽  
Weimin Chen
Keyword(s):  
Shallow Water ◽  
Water Depth ◽  
Deep Water ◽  
Water Resistance ◽  
Model Tests ◽  
System 2 ◽  
Changing Trend ◽  
The Difference ◽  
Transport Vessel ◽  
Resistance Performance

Abstract Articulated pusher barge vessel is a short-distance transport vessel with good economic performance and practicability, which is widely used in the Yangtze River of China. In this present work, the resistance performance of articulated pusher barge vessel in deep water and shallow water was studied by model tests in the towing tank and basin of Shanghai Ship and Shipping Research Institute. During the experimental investigation, the articulated pusher barge vessel was divided into three parts: the pusher, the barge and the articulated pusher barge system. Firstly, the deep water resistance performance of the articulated pusher barge system, barge and the pusher at design draught T was studied, then the water depth h was adjusted, and the shallow water resistance at h/T = 2.0, 1.5 and 1.2 was tested and studied respectively, and the difference between deep water resistance and shallow water resistance at design draught were compared. The results of model tests and analysis show that: 1) in the study of deep water resistance, the total resistance of the barge was larger than that of the articulated pusher barge system. 2) for the barge, the shallow water resistance increases about 0.4–0.7 times at h/T = 2.0, 0.5–1.1 times at h/T = 1.5, and 0.7–2.3 times at h/T = 1.2. 3) for the pusher, the shallow water resistance increases about 1.0–0.4 times at h/T = 2.7, 1.2–0.9 times at h/T = 2.0, and 1.7–2.4 times at h/T = 1.6. 4) for the articulated pusher barge system, the shallow water resistance increases about 0.2–0.3 times at h/T = 2.0, 0.5–1.3 times at h/T = 1.5, and 1.0–3.5 times at h/T = 1.2. Furthermore, the water depth Froude number Frh in shallow water was compared with the changing trend of resistance in shallow water.

scholarly journals OPTIMIZATION OF THE WAVECAT WAVE ENERGY CONVERTER

2012 ◽  
Vol 1 (33) ◽  
pp. 5 ◽  
Author(s):  
Hernan Fernandez ◽  
Gregorio Iglesias ◽  
Rodrigo Carballo ◽  
Alberte Castro ◽  
Marcos Sánchez ◽  
...  
Keyword(s):  
Physical Model ◽  
Wave Energy ◽  
Model Tests ◽  
Irregular Waves ◽  
Intermediate Water ◽  
Plan View ◽  
Santiago De Compostela ◽  
Wave Energy Converters ◽  
Physical Model Tests ◽  
The Difference

The development of efficient, reliable Wave Energy Converters (WECs) is a prerequisite for wave energy to become a commercially viable energy source. Intensive research is currently under way on a number of WECs, among which WaveCat©—a new WEC recently patented by the University of Santiago de Compostela. In this sense, this paper describes the WaveCat concept and its ongoing development and optimization. WaveCat is a floating WEC intended for operation in intermediate water depths (50–100 m). Like a catamaran, it consists of two hulls—from which it derives its name. The difference with a conventional catamaran is that the hulls are not parallel but convergent; they are joined at the stern, forming a wedge in plan view. Physical model tests of a 1:30 model were conducted in a wave tank using both regular and irregular waves. In addition to the waves and overtopping rates, the model displacements were monitored using a non-intrusive system. The results of the physical model tests will be used to validate the 3D numerical model, which in turn will be used to optimize the design of WaveCat for best performance under a given set of wave conditions.

DP-Stability During Heavy Lift Operations Using a Modified Kalman Filter

2018 ◽  
Author(s):  
Eelco Harmsen ◽  
Radboud van Dijk ◽  
Petter Stuberg
Keyword(s):  
Kalman Filter ◽  
Dynamic Positioning ◽  
Mooring System ◽  
Engineering Analysis ◽  
Single Object ◽  
Joint Effort ◽  
Wide Range ◽  
Floating Object ◽  
Heavy Lift ◽  
Modified Kalman Filter

During heavy lift operations, staying on position using a Dynamic Positioning (DP) system offers many advantages compared with a mooring system. However, when the vessel is connected to another fixed or floating object during the lifting operation through its hoist wires it may experience instabilities in the DP-system. These DP-instabilities are caused by the inability of the DP system to handle the relatively stiff external spring of the hoist wire correctly. This phenomenon is well known and mitigating measures such as Heavy Lift Mode have been developed over the years that work well for stationary vessels. However, when two vessels are lifting a single object together (e.g. QUAD lift), existing solutions to prevent this DP-instability are insufficient, as the nature of such lift requires a synchronous move on DP. During studies to the fundamental behavior of a DP system during heavy lift operations it is found that modifications to the Kalman filter can prevent these DP-instabilities. Heerema Marine Contractors presented the DP-stability challenges to Kongsberg Maritime, and a joint effort resulted in an implementation of a modified Kalman filter in the Kongsberg Maritime DP system. Also a dedicated engineering analysis to predict risk of DP-instabilities for specific lift configurations has been developed. The modified DP-system is tested in large number of simulations (both desktop and a full mission simulator) to test the ability of the updated DP-system to deal with a wide range of specific heavy lift conditions. Results were evaluated between Heerema office, Kongsberg and offshore personnel for developing the optimum Kalman filter parameters. Finally, the system is tested during a dedicated DP-trial program onboard Thialf. As the results of all these tests were very successful, the new High Kalman filter was made available onboard Thialf as a permanent option next to the original functionalities. The paper addresses the steps followed to define the new Kalman filter settings, the simulations performed to test the new filter as well as to show results of the offshore tests that were done to validate the numerical analysis.

Application of Kalman Filter Technology to Integrated INS/DR Navigation System for Land Vehicle

2013 ◽  
Vol 411-414 ◽  
pp. 912-916 ◽  
Author(s):  
Ying Chen ◽  
Xia Jiang Zhang ◽  
Yuan Yuan Xue ◽  
Zhen Kang ◽  
Ting Shang
Keyword(s):  
Kalman Filter ◽  
Navigation System ◽  
Dead Reckoning ◽  
Position Error ◽  
Integrated System ◽  
Integrated Navigation ◽  
Integrated Navigation System ◽  
Attitude Error ◽  
Result Show ◽  
The Difference

Strap-down INS is composed of fiber gyroscope. Position error propagation equation and position update algorithm of dead reckoning is deduced in this paper. The Kalman filter is proposed for compensation error of integrated system. The difference of velocity between INS and DR is used as the input of Kalman filter, attitude error, velocity error, position error and scale factor error are to be estimated which compensate and rectify the errors of integrated navigation system. By carrying out experiment upon vehicular navigation system in use of Kalman filter, the errors of integrated navigation system are estimated accurately. Experiment result show that the method not only can effectively improve precision of the system, but also is simple and convenient, so it is more suitable for practical application.

Autonomous Navigation of Mars Probes by Combining Optical Data of Viewing Martian Moons and SST Data

2015 ◽  
Vol 68 (6) ◽  
pp. 1019-1040 ◽  
Author(s):  
Pengbin Ma ◽  
Fanghua Jiang ◽  
Hexi Baoyin
Keyword(s):  
Kalman Filter ◽  
Autonomous Navigation ◽  
Unscented Kalman Filter ◽  
Optical Measurement ◽  
Optical Data ◽  
Deep Space Exploration ◽  
Rank Defect ◽  
The Difference ◽  
Navigation Accuracy ◽  
Navigation Information

Autonomous navigation has become a key technology for deep space exploration missions. Phobos and Deimos, the two natural moons of Mars, are important optical navigation information sources available for Mars missions. However, during the phase of the probe orbiting close to Mars, the ephemeris bias and the difference between the barycentre and the centre of brightness of a Martian moon will result in low navigation accuracy. On the other hand, Satellite-to-Satellite Tracking (SST) can achieve convenient and high accuracy observation for autonomous navigation. However, this cannot apply for a Mars mission during the Mars orbit phase only by SST data because of a rank defect problem of the Jacobian matrix. To improve the autonomous navigation accuracy of Mars probes, this paper presents a new autonomous navigation method that combines SST radio data provided by two probes and optical measurement by viewing the natural Martian moons. Two sequential orbit determination algorithms, an Extended Kalman Filter (EKF) and Unscented Kalman Filter (UKF) are compared. Simulation results show this method can obtain high autonomous navigation accuracy during the probe's Mars Orbit phase.

scholarly journals Ensemble Kalman Filter and 4D-Var Intercomparison with the Japanese Operational Global Analysis and Prediction System

2010 ◽  
Vol 138 (7) ◽  
pp. 2846-2866 ◽  
Author(s):  
Takemasa Miyoshi ◽  
Yoshiaki Sato ◽  
Takashi Kadowaki
Keyword(s):  
Kalman Filter ◽  
Bias Correction ◽  
Global Analysis ◽  
Weather Prediction ◽  
Lower Troposphere ◽  
Correction Method ◽  
Jma Model ◽  
Temperature Bias ◽  
Comparable Performance ◽  
The Difference

Abstract The local ensemble transform Kalman filter (LETKF) is implemented and assessed with the experimental operational system at the Japanese Meteorological Agency (JMA). This paper describes the details of the LETKF system and verification of deterministic forecast skill. JMA has been operating a four-dimensional variational data assimilation (4D-Var) system for global numerical weather prediction since 2005. The main purpose of this study is to make a reasonable comparison between the LETKF and the operational 4D-Var. Several forecast–analysis cycle experiments are performed to find sensitivity to the parameters of the LETKF. The difference between additive and multiplicative error covariance inflation schemes is investigated. Moreover, an adaptive bias correction method for satellite radiance observations is proposed and implemented, so that the LETKF is equipped with functionality similar to the variational bias correction used in the operational 4D-Var. Finally, the LETKF is compared with the operational 4D-Var. Although forecast verification scores of the two systems relative to each system’s own analyses and to radiosonde observations show some disagreement, the overall conclusion indicates that the LETKF and 4D-Var have essentially comparable performance. The LETKF shows larger temperature bias in the lower troposphere mainly over the ocean, which is related to a well-known JMA model bias that plays an important role in the significant degradation of the forecast scores in the SH. The LETKF suffers less of a performance degradation than 4D-Var in the absence of satellite radiance assimilation. This suggests that better treatment of satellite radiances would be important in future developments toward operational use of the LETKF. Developing both LETKF and 4D-Var at JMA has shown significant benefits by the synergistic effect and is the recommended strategy for the moment.

scholarly journals ACCURACY ENHANCEMENT OF A LOW COST INS/GPS INTEGRATION SYSTEM FOR LAND APPLICATIONS

2009 ◽  
Vol 12 (4) ◽  
pp. 30-38
Author(s):  
Tan Duc Tran ◽  
Thuy Phu Nguyen
Keyword(s):  
Kalman Filter ◽  
Good Accuracy ◽  
Low Cost ◽  
Integration System ◽  
Feed Forward ◽  
Accuracy Enhancement ◽  
Motion Constraints ◽  
Vehicle Motion ◽  
Gps System

In this paper, the design of the low cost INS/GPS integration system is addressed with good accuracy. The Strapdown INS (SINS) and Cascade Kalman filter have been tested to ensure that the system can be operated flexibly between feed forward and feedback modes due to various GPS conditions. The vehicle motion constraints are also utilized to reduce the INS error degradation during the periods of GPS unavailability. The experiment results shown that the INS/GPS system can be applied to land applications in challenging GPS environments.

scholarly journals General Model and SOC Estimation of Battery

2021 ◽  
Vol 15 ◽  
pp. 155-163
Author(s):  
Li Meng ◽  
Haipeng Guo ◽  
Xiaowei Zhao
Keyword(s):  
Kalman Filter ◽  
General Model ◽  
Unscented Kalman Filter ◽  
Measurement Data ◽  
Work Conditions ◽  
Filter Method ◽  
Soc Estimation ◽  
The Difference ◽  
Kalman Filter Method ◽  
Set Up

Monitoring the battery state is of great importance for the safety and normal of the systems which are powered by batteries. SOC (State of Charge) is one of the most important state parameters of battery. SOC cannot be measured directly. The Kalman filter algorithm is one of the techniques often applied to estimate SOC value. An accurate model is necessary for this algorithm. In this paper, a general SOC model is set up. It takes into account not only the difference between discharging and charging work conditions, but also the influence of the working atmosphere, such as temperature and discharging rate. Then based on this general model, unscented Kalman filter method is used to predict the SOC value. It can avoid the error which is caused by ignoring high-order terms, which is a shortcoming exist in the extended Kalman filter method. The simulation experiments prove the approach can get satisfactory results even when the measurement data is mixed with noise or the initial SOC value is not accurate.

scholarly journals Sustainable Method Using Filtering Techniques for a Fermentation Process State Estimation

2020 ◽  
Vol 12 (17) ◽  
pp. 7105 ◽  
Author(s):  
Anca Sipos
Keyword(s):  
Kalman Filter ◽  
Fermentation Process ◽  
Alcoholic Fermentation ◽  
Batch Process ◽  
Performance Criterion ◽  
Monitoring And Control ◽  
Error Norm ◽  
Process Monitoring And Control ◽  
The Difference ◽  
Filtering Techniques

Winemaking is concerned about sustainable energy availability that implies new methods for process monitoring and control. The aim of this paper is to realize a comparative analysis of the possibilities offered using estimation techniques, balances, and filtering techniques such as the Kalman filter (KF) and the extended Kalman filter (EKF), to obtain indirect information about the alcoholic fermentation process during winemaking. Thus, an estimation solution of the process variables in the exponential growing phase is proposed, using an extended observer. In addition, two estimation solutions of this process with the EKF and an estimation of the decay phase of the fermentation process are presented. The difference between the two EKF variants consisted of taking into consideration the indicator of the integral of the error norm square for the second EKF, for which the performance criterion was the statistical average of this indicator. Results from the simulation of the estimation programs of the two EKF variants were more than satisfactory. This research provides a basis for using an EKF designed for advanced control of the alcoholic fermentation batch process as a knowledge-based system.

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