The Effects of the Gravity Center on the Hydrodynamic Behavior of a Wave Rider Buoy

2009 ◽  
Author(s):  
Mohsen Goodarzi
Keyword(s):  
Dynamic Response ◽  
Dynamic Performance ◽  
Numerical Procedure ◽  
Center Of Gravity ◽  
Linear Matrix ◽  
Hydrodynamic Coefficients ◽  
Hydrodynamic Behavior ◽  
Gravity Center ◽  
The Stability

A numerical procedure was employed to investigate the dynamic performance of a wave rider buoy. The linear matrix form has been derived to describe the equations of the motion. The hydrostatic and hydrodynamic coefficients of the wave rider buoy have been computed. Three cases of the buoy center of gravity were considered. The numerical results showed that, the stability of the buoy was increased by lowering the buoy center of gravity, but the quality of the dynamic response should be reduced, which is a disadvantage regarding the mission of the buoy.

Novel robust controller design for load sway reduction in double-pendulum overhead cranes

2018 ◽  
Vol 233 (12) ◽  
pp. 4359-4371 ◽  
Author(s):  
Huimin Ouyang ◽  
Xin Deng ◽  
Huan Xi ◽  
Jinxin Hu ◽  
Guangming Zhang ◽  
...  
Keyword(s):  
Controller Design ◽  
Dynamic Performance ◽  
Optimization Method ◽  
Linear Matrix ◽  
Double Pendulum ◽  
Control Performance ◽  
Mass Property ◽  
Length Changes ◽  
The Stability ◽  
Dynamic Performance Analysis

It is seen that when the hook mass is larger than the load mass or the load has distributed mass property, the load sway of the crane system presents as double-pendulum effect. In this situation, crane system has two different natural frequencies so that the sway characteristic becomes more complex and greatly increases the difficulty of the dynamic performance analysis and controller design. Moreover, the rope length changes significantly affect the stability and control performance of the crane system. In order to solve the aforementioned problems, the linear dynamics of a two-dimensional overhead crane with double-pendulum effect is derived based on a disturbance observer, and is decoupled for controller design by modal analysis. Next, a state feedback controller is presented to achieve robust control performance for a given range of rope length changes. The controller gains are obtained via linear matrix inequality optimization method. Finally, numerical simulations and experimental results validate that the proposed method has superior control performance.

Dynamic Response of Eccentric Swinging Sheet Transfer Mechanism with Kinematic Pair Clearances

2013 ◽  
Vol 312 ◽  
pp. 182-185
Author(s):  
Fang Cai ◽  
Jian Qing Zhang ◽  
Xiu Feng Ma
Keyword(s):  
Dynamic Response ◽  
Dynamic Characteristics ◽  
Dynamic Performance ◽  
Transfer Mechanism ◽  
Kinematic Pair ◽  
Nonlinear Dynamic Response ◽  
Nonlinear Characteristics ◽  
Continuous Contact ◽  
The Stability ◽  
Transfer Mechanisms

To research the influence of kinematic pair clearances on the dynamic performance of eccentric swinging sheet transfer mechanism used in Sheet-fed offset J2108, a dynamic model was established based on the clearances characteristics and the continuous contact hypothesis. Consequently, the dynamic characteristics of sheet transfer mechanisms output can be researched quantitatively. The results indicate that sheet transfer mechanisms dynamic response appears strong nonlinear characteristics while considering kinematic pair clearances, which seriously affects the sheet transfer mechanisms stability and precision. Therefore, the study on the nonlinear dynamic response of sheet transfer mechanism can provide foundation to improve the stability.

Multiobjective Robust Regulating and Protecting Control for Aeroengines

2009 ◽  
Vol 131 (6) ◽  
Author(s):  
Daren Yu ◽  
Xiaofeng Liu ◽  
Wen Bao ◽  
Zhiqiang Xu
Keyword(s):  
Control Method ◽  
Design Method ◽  
Dynamic Performance ◽  
Switching Control ◽  
Linear Matrix ◽  
Matrix Inequality ◽  
Proportional Integral Derivative ◽  
Engine Control System ◽  
Switching Performance ◽  
The Stability

The multiobjective regulating and protecting control method presented here will enable improved control of multiloop switching control of an aeroengine. The approach is based on switching control theory, the switching performance objectives and the strategy are given, and a family of H∞ proportional-integral-derivative controllers was designed by using linear matrix inequality optimization algorithm. The simulation shows that using the switching control design method not only can improve the dynamic performance of the engine control system but also can guarantee the stability in some peculiar occasions.

The Study on the Dynamic Response Performance of PEMFC Stack with Electrodeposited Pt/C-RuO2·xH2O Electrode

2013 ◽  
Vol 750-752 ◽  
pp. 2263-2266
Author(s):  
Li Bin Fu ◽  
Lu Lu ◽  
Hong Feng Xu ◽  
Hong Zhao ◽  
Rui Ming Ren
Keyword(s):  
Particle Size ◽  
Dynamic Response ◽  
Dynamic Performance ◽  
Average Particle Size ◽  
Average Particle ◽  
Fuel Cell Vehicles ◽  
Catalyst Layers ◽  
Response Performance ◽  
Solgel Method ◽  
The Stability

Dynamic response performance of PEMFC affects its durability and reliability significantly. So improving on dynamic performance of PEMFC has become the key for prolonging PEMFC life in fuel cell vehicles application. In this study, in order to promote the PEMFC dynamic response performance, RuO2·xH2O was prepared by solgel method and then sprayed onto catalyst layers. The RuO2·xH2O prepared was characterized by TEM, which shows the average particle size of RuO2·xH2O was 8 nm and particulates were well distributed. A 10-cell stack using MEAs with and without RuO2·xH2O was assembled and studied under different relative humidity. It was found that added with RuO2·xH2O dramatically improves the dynamic response performance, which revealing that RuO2·xH2O can buffer the voltage undershoot and improve the stability and lifetime of PEMFC stack.

Criteria for evaluation of the coordinate measurements quality of parts geometric parameters at pilot-experimental production

2019 ◽  
pp. 3-8
Author(s):  
N.Yu. Bobrovskaya ◽  
M.F. Danilov
Keyword(s):  
Quality Indicators ◽  
Quality Management System ◽  
Technical Specification ◽  
Experimental Production ◽  
Technological Heredity ◽  
Coordinate Measurements ◽  
Reasonable Choice ◽  
The Stability ◽  
Geometric Elements

The criteria of the coordinate measurements quality at pilot-experimental production based on contemporary methods of quality management system and traditional methods of the measurements quality in Metrology are considered. As an additional criterion for quality of measurements, their duration is proposed. Analyzing the problem of assessing the quality of measurements, the authors pay particular attention to the role of technological heredity in the analysis of the sources of uncertainty of coordinate measurements, including not only the process of manufacturing the part, but all stages of the development of design and technological documentation. Along with such criteria as the degree of confidence in the results of measurements; the accuracy, convergence, reproducibility and speed of the results must take into account the correctness of technical specification, and such characteristics of the shape of the geometric elements to be controlled, such as flatness, roundness, cylindrical. It is noted that one of the main methods to reduce the uncertainty of coordinate measurements is to reduce the uncertainty in the initial data and measurement conditions, as well as to increase the stability of the tasks due to the reasonable choice of the basic geometric elements (measuring bases) of the part. A prerequisite for obtaining reliable quality indicators is a quantitative assessment of the conditions and organization of the measurement process. To plan and normalize the time of measurements, the authors propose to use analytical formulas, on the basis of which it is possible to perform quantitative analysis and optimization of quality indicators, including the speed of measurements.

Statistical Management of Food Production Processes

2020 ◽  
pp. 30-35
Author(s):  
N.A. Jurk ◽  
Keyword(s):  
Production Process ◽  
Control Chart ◽  
Food Production ◽  
Time Interval ◽  
Bakery Products ◽  
Shewhart Control ◽  
Manufactured Products ◽  
Mnemonic Technique ◽  
The Stability

The article presents scientific research in the field of statistical controllability of the food production process using the example of bakery products for a certain time interval using statistical methods of quality management. During quality control of finished products, defects in bakery products were identified, while the initial data were recorded in the developed form of a checklist for registering defects. It has been established that the most common defect is packaging leakage. For the subsequent statistical assessment of the stability of the production process and further analysis of the causes of the identified defect, a Shewhart control chart (p-card by an alternative feature) was used, which allows you to control the quality of manufactured products by the number of defects detected. Analyzing the control chart, it was concluded that studied process is conditionally stable, and the emerging defects are random. At the last stage of the research, the Ishikawa causal diagram was used, developed using the 6M mnemonic technique, in order to identify the most significant causes that affect the occurrence of the considered defect in bakery products. A more detailed study will allow the enterprise to produce food products that meet the established requirements.

Dynamic Performance of High-Speed Electric Multiple Unit within Multi-Body System Simulation

2019 ◽  
Vol 12 (4) ◽  
pp. 339-349
Author(s):  
Junguo Wang ◽  
Daoping Gong ◽  
Rui Sun ◽  
Yongxiang Zhao
Keyword(s):  
High Speed ◽  
Rapid Development ◽  
Dynamic Performance ◽  
Body System ◽  
High Speed Railway ◽  
Evaluation Indexes ◽  
Actual Operation ◽  
Multiple Unit ◽  
The Stability ◽  
Multi Body

Background: With the rapid development of the high-speed railway, the dynamic performance such as running stability and safety of the high-speed train is increasingly important. This paper focuses on the dynamic performance of high-speed Electric Multiple Unit (EMU), especially the dynamic characteristics of the bogie frame and car body. Various patents have been discussed in this article. Objective: To develop the Multi-Body System (MBS) model of EMU, verify whether the dynamic performance meets the actual operation requirements, and provide some useful information for dynamics and structural design of the proposed EMU. Methods: According to the technical characteristics of a typical EMU, a MBS model is established via SIMPACK, and the measured data of China high-speed railway is taken as the excitation of track random irregularity. To test the dynamic performance of the EMU, including the stability and safety, some evaluation indexes such as wheel-axle lateral forces, wheel-axle lateral vertical forces, derailment coefficients and wheel unloading rates are also calculated and analyzed in detail. Results: The MBS model of EMU has better dynamic performance especially curving performance, and some evaluation indexes of the stability and safety have also reached China’s high-speed railway standards. Conclusion: The effectiveness of the proposed MBS model is verified, and the dynamic performance of the MBS model can meet the design requirements of high-speed EMU.

Enlarging the region of stability in robust model predictive controller based on dual-mode control

2021 ◽  
pp. 014233122110123
Author(s):  
Fatemeh Khani ◽  
Mohammad Haeri
Keyword(s):  
Stability Region ◽  
Linear Matrix ◽  
Input State ◽  
Dual Mode ◽  
Model Predictive Controller ◽  
Mode Control ◽  
Robust Model ◽  
Output Constraints ◽  
Predictive Controller ◽  
The Stability

Industrial processes are inherently nonlinear with input, state, and output constraints. A proper control system should handle these challenging control problems over a large operating region. The robust model predictive controller (RMPC) could be an linear matrix inequality (LMI)-based method that estimates stability region of the closed-loop system as an ellipsoid. This presentation, however, restricts confident application of the controller on systems with large operating regions. In this paper, a dual-mode control strategy is employed to enlarge the stability region in first place and then, trajectory reversing method (TRM) is employed to approximate the stability region more accurately. Finally, the effectiveness of the proposed scheme is illustrated on a continuous stirred tank reactor (CSTR) process.

scholarly journals Identifying Stabilising Effects on Survey Based Life Satisfaction Using Quasi-maximum Likelihood Estimation

2021 ◽  
Author(s):  
Johannes Klement
Keyword(s):  
Life Satisfaction ◽  
Maximum Likelihood ◽  
Maximum Likelihood Estimation ◽  
Negative Binomial ◽  
Measurement Instrument ◽  
Likelihood Estimation ◽  
Satisfaction Scale ◽  
Quasi Maximum Likelihood ◽  
The Stability

AbstractTo which extent do happiness correlates contribute to the stability of life satisfaction? Which method is appropriate to provide a conclusive answer to this question? Based on life satisfaction data of the German SOEP, we show that by Negative Binomial quasi-maximum likelihood estimation statements can be made as to how far correlates of happiness contribute to the stabilisation of life satisfaction. The results show that happiness correlates which are generally associated with a positive change in life satisfaction, also stabilise life satisfaction and destabilise dissatisfaction with life. In such as they lower the probability of leaving positive states of life satisfaction and increase the probability of leaving dissatisfied states. This in particular applies to regular exercise, volunteering and living in a marriage. We further conclude that both patterns in response behaviour and the quality of the measurement instrument, the life satisfaction scale, have a significant effect on the variation and stability of reported life satisfaction.

A new control approach for a class of linear switched systems with time-varying delay

2021 ◽  
pp. 014233122199272
Author(s):  
Abbas Zabihi Zonouz ◽  
Mohammad Ali Badamchizadeh ◽  
Amir Rikhtehgar Ghiasi
Keyword(s):  
Stability Analysis ◽  
Linear Matrix Inequalities ◽  
Linear Matrix ◽  
Switching Systems ◽  
Time Varying ◽  
Matrix Inequalities ◽  
Time Varying Delay ◽  
Linear Switching Systems ◽  
The Stability ◽  
Varying Delay

In this paper, a new method for designing controller for linear switching systems with varying delay is presented concerning the Hurwitz-Convex combination. For stability analysis the Lyapunov-Krasovskii function is used. The stability analysis results are given based on the linear matrix inequalities (LMIs), and it is possible to obtain upper delay bound that guarantees the stability of system by solving the linear matrix inequalities. Compared with the other methods, the proposed controller can be used to get a less conservative criterion and ensures the stability of linear switching systems with time-varying delay in which delay has way larger upper bound in comparison with the delay bounds that are considered in other methods. Numerical examples are given to demonstrate the effectiveness of proposed method.

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