Synthesis of a Limited-Bandwidth Fractional Differentiator Made in Hydropneumatic Technology

2005 ◽  
Author(s):  
Pascal Serrier ◽  
Xavier Moreau ◽  
Alain Oustaloup
Keyword(s):  
Vibration Isolation ◽  
Technological Parameters ◽  
Hydraulic Test ◽  
Limited Bandwidth ◽  
Crone Control ◽  
The Stability ◽  
Control Methodology ◽  
Crone Suspension ◽  
Fractional Differentiator ◽  
Made In

In a vibration isolation context, fractional derivative can be used to design suspensions which allow to obtain similar performances in spite of parameters uncertainties. This paper presents the synthesis and the achievement of a CRONE suspension. A CRONE suspension is synthesised using the CRONE control methodology. Its transfer function is a limited bandwidth fractional differentiator. After the formulation of vibration isolation problems as control law synthesis problems, a method to determine the technological parameters of a CRONE suspension is proposed and is applied to a CRONE hydraulic test bench. A parallel arrangement of dissipative and capacitive components and a gamma arrangement are compared. They lead to the same unusual performances: the stability degree robustness and the rapidity robustness.

A New CRONE Suspension: More Compact and More Efficient: Part 2—Synthesis and Achievement

2009 ◽  
Author(s):  
Audrey Rizzo ◽  
Xavier Moreau ◽  
Alain Oustaloup ◽  
Vincent Hernette
Keyword(s):  
Transfer Function ◽  
Fractional Derivative ◽  
Vibration Isolation ◽  
Suspension System ◽  
Technological Parameters ◽  
Stability Degree ◽  
Parallel Arrangement ◽  
The Stability ◽  
Crone Suspension ◽  
The Ideal

In a vibration isolation context, fractional derivative can be used to design suspensions which allow to obtain similar performances in spite of parameters uncertainties. This paper presents the synthesis and the achievement of a new Hydractive CRONE suspension system. After the study of the different constraint in suspension in the first paper, the ideal transfer function of the hydractive CRONE suspension is created and simulated in different case. Then a method to determine the technological parameters is proposed. A parallel arrangement of dissipative and capacitive components and a gamma arrangement are compared. They lead to the same unusual performances: the stability degree robustness and the rapidity robustness.

An hourglass-type electromagnetic isolator with negative resistance electromagnetic shunt circuit

2020 ◽  
Vol 64 (1-4) ◽  
pp. 549-556
Author(s):  
Yajun Luo ◽  
Linwei Ji ◽  
Yahong Zhang ◽  
Minglong Xu ◽  
Xinong Zhang
Keyword(s):  
Vibration Isolation ◽  
Electromechanical Coupling ◽  
Coupling Effect ◽  
Negative Resistance ◽  
Isolation System ◽  
Amplitude Vibration ◽  
Vibration Responses ◽  
The Stability ◽  
Isolation Performance ◽  
Shunt Circuit

The present work proposed an hourglass-type electromagnetic isolator with negative resistance (NR) shunt circuit to achieve the effective suppression of the micro-amplitude vibration response in various advanced instruments and equipment. By innovatively design of combining the displacement amplifier and the NR electromagnetic shunt circuit, the current new type of vibration isolator not only can effectively solve the problem of micro-amplitude vibration control, but also has significant electromechanical coupling effect, to obtain excellent vibration isolation performance. The design of the isolator and motion relationship is presented firstly. The electromechanical coupling dynamic model of the isolator is also given. Moreover, the optimal design of the NR electromagnetic shunt circuit and the stability analysis of the vibration isolation system are carried out. Finally, the simulation results about the transfer function and vibration responses demonstrated that the isolator has a significant isolation performance.

Observations on some basal failures in sheeted excavations

1970 ◽  
Vol 7 (2) ◽  
pp. 136-144 ◽  
Author(s):  
V. Milligan ◽  
K. Y. Lo
Keyword(s):  
Shear Strength ◽  
Ground Water ◽  
Groundwater Level ◽  
Soil Conditions ◽  
Remedial Measures ◽  
Factors Influencing ◽  
Water Head ◽  
The Stability ◽  
Made In

In excavations below groundwater level, instability of the base may result from the inflow of water into the excavation. The most important factors influencing the stability are the ground water and detailed soil conditions at the site.Construction problems encountered in excavations in clay strata, underlain by pervious water bearing layers, are described. The remedial measures adopted in each case are also discussed. From a study of the observations made in the case records, it is suggested that excavation in intact clays may be carried out to depths exceeding that limited by the ratio of t/h = 0.5, where t is the distance from the bottom of the excavation to the top of the water bearing stratum, and h is the water head at the top of the water bearing stratum, provided that the clay is not disturbed during construction so that the shear strength of the clay is preserved.

Enhanced Grey Variable Structure Control Methodology of Parallel-Connected DC-AC Inverters for Ultra-Precision Machining

2015 ◽  
Vol 661 ◽  
pp. 29-35
Author(s):  
En Chih Chang ◽  
Hung Liang Cheng ◽  
Chien Hsuan Chang ◽  
Jin Wei Liu ◽  
Chih Hsien Chuang ◽  
...  
Keyword(s):  
Output Voltage ◽  
Variable Structure Control ◽  
Variable Structure ◽  
Precision Machining ◽  
Structure Control ◽  
Highly Nonlinear ◽  
Ultra Precision ◽  
The Stability ◽  
Control Methodology ◽  
Voltage Harmonics

This paper develops an enhanced grey variable structure controlled DC-AC inverter in parallel, and is suitable for the application of ultra-precision machining (UPM). The enhanced grey variable structure control methodology consists of a nonlinear sliding function (NSF) and a grey model, GM(2,1). The NSF has finite system-state convergence time, and thus the AC output voltage regulation and balanced current-sharing among the parallel modules can be achieved. However, once the loading of the UPM is a highly nonlinear condition, the chatter still exists in NSF. The chatter may cause heat losses and high voltage harmonics in parallel-connected DC-AC inverter output, and thus deteriorates the stability and reliability of the UPM. To eliminate the chatter, the control gains of the NSF can be adjusted by the use of the GM(2,1) under system uncertainty bounds are overestimated. With the enhanced methodology, the parallel-connected DC-AC inverter yields a high-quality AC output voltage with low voltage harmonics and fast dynamic response under highly nonlinear loading, thus achieving the stability and reliability of the UPM. Experimental results are performed to demonstrate the enhanced methodology.

scholarly journals Influence of Technological Parameters on the Emision on DLP 3D Printing Process

2020 ◽  
Vol 70 (12) ◽  
pp. 4387-4392
Keyword(s):  
3D Printing ◽  
Point Of View ◽  
Particulate Emissions ◽  
Technological Parameters ◽  
Printing Process ◽  
Laboratory Activity ◽  
Emission Point ◽  
Measurement Methodology ◽  
Made In

The present work addresses the issue of emissions requires it made in resin polymerization processes at 3D digital light process (DLP) printing. From an emission point of view, both particulate and chemical emissions are analysed in the form of gases during the DLP printing process. In the paper, we present first the element, which are study. In second part of the paper, we presented the printer, material for printing, measuring apparatus for emission and measurement methodology. In the three part of paper, we made the determinations for gas emissions. Will follow the determinations for particulate emissions. In the final chapter, the data generated by the printing emissions related to the problems specific to the laboratory activity and it has made the specific conclusion in rapport with the printing process. Keywords: 3D printing; emission particles; air pollution, resin material, DLP printing

scholarly journals Kerukunan Umat Beragama: Relevansi Pasal 25 Piagam Madinah dan Pasal 29 UUD 1945

2019 ◽  
Vol 21 (2) ◽  
pp. 162
Author(s):  
Nurul Fajriah
Keyword(s):  
20Th Century ◽  
Religious Diversity ◽  
The State ◽  
Religious Communities ◽  
Modern Times ◽  
Indonesian Government ◽  
Important Concern ◽  
Similarities And Differences ◽  
The Stability ◽  
Made In

This article is a study of literature describing religious harmony: the relevance of Article 25 of the Medina Charter and Article 29 of the 1945 Constitution. The Medina Charter was made in the 7th century (classical century) and Article 29 of the 1945 Constitution was born in modern times, around the 20th century. Both have relevancy which states that every citizen is free to adhere to their respective religions. The plurality of society in Indonesia has similarities and differences from the plurality of society in Medina around 622 AD. The stability and harmony of religious communities in the Medina at that time was regulated in the Medina charter which is the constitution of the Medina state. Harmony among religious communities in Indonesia is also an important concern of the Indonesian government as stipulated in Article 29 of the 1945 Constitution. Freedom of religion is guaranteed by the state because the state believes that religious diversity is not a disintegrating factor for the Indonesian people.Abstrak: Artikel ini adalah kajian literatur yang mendeskripsikan kerukunan umat beragama: relevansi pasal 25 Piagam Madinah dan Pasal 29 UUD 1945. Piagam Madinah dibuat pada abad VII (abad klasik) dan pasal 29 UUD 1945 baru lahir pada zaman modern, sekitar abad XX. Keduanya memiliki relevansi yang menyatakan bahwa setiap warga negara bebas menganut agamanya masing-masing. Kemajemukan masyarakat di Indonesia mempunyai sisi-sisi persamaan dan perbedaan dengan kemajemukan masyarakat di Madinah sekitar tahun 622 M. Keberlangsungan dan keharmonisan umat beragama di negara Madinah pada waktu itu diatur dalam piagam Madinah yang merupakan konstitusi negara Madinah. Kerukunan antar umat beragama di Indonesia juga menjadi perhatian penting pemerintah dengan adanya kebijakan Negara Republik Indonesia dari segi agama yang tertuang dalam pasal 29 UUD 1945. Kebebasan beragama ini dijamin oleh negara karena keyakinan bahwa keberagaman agama tidak akan menjadi disentegrating factor bagi bangsa Indonesia

scholarly journals A Novel Piecewise Frequency Control Strategy Based on Fractional-Order Filter for Coordinating Vibration Isolation and Positioning of Supporting System

Sensors ◽  
2020 ◽  
Vol 20 (18) ◽  
pp. 5307
Author(s):  
Yeying Tao ◽  
Wei Jiang ◽  
Bin Han ◽  
Xiaoqing Li ◽  
Ying Luo ◽  
...  
Keyword(s):  
Fractional Order ◽  
Control Strategy ◽  
Vibration Isolation ◽  
Frequency Control ◽  
Low Frequency ◽  
Stability Margin ◽  
System Stability ◽  
Supporting System ◽  
Frequency Position ◽  
The Stability

A piecewise frequency control (PFC) strategy is proposed in this paper for coordinating vibration isolation and positioning of supporting systems under complex disturbance conditions, such as direct and external disturbances. This control strategy is applied in an active-passive parallel supporting system, where relative positioning feedback for positioning and absolute velocity feedback for active vibration isolation. The analysis of vibration and deformation transmissibility shows that vibration control increases low-frequency position error while positioning control amplifies high-frequency vibration amplitude. To overcome this contradiction across the whole control bandwidth, a pair of Fractional-Order Filters (FOFs) is adopted in the PFC system, which increases the flexibility in the PFC design by introducing fraction orders. The system stability analysis indicates that the FOFs can provide a better stability margin than the Integral-Order Filters (IOFs), so the control gains are increased to get a better performance on the AVI and positioning. The PFC based on FOFs can suppress the peak amplitude at the natural frequency which cannot be avoided when using the IOFs. The constrained nonlinear multivariable function is formed by the required performance and the stability of the system, then the controller parameters are optimized effectively. Lastly, the effectiveness of the proposed method is verified by experiments.

EFFECT OF ADDED TIP MASS ON THE NONLINEAR FLAPWISE AND CHORDWISE VIBRATION OF CANTILEVER COMPOSITE BEAM UNDER BASE EXCITATION

2012 ◽  
Vol 12 (02) ◽  
pp. 285-310 ◽  
Author(s):  
M. EFTEKHARI ◽  
M. MAHZOON ◽  
S. ZIAEI-RAD
Keyword(s):  
Cantilever Beam ◽  
Multiple Scales ◽  
Equilibrium Points ◽  
Laminated Composite ◽  
Base Excitation ◽  
System A ◽  
Autoparametric Resonance ◽  
The Stability ◽  
Tip Mass ◽  
Made In

In this paper, a comparative study is performed for a symmetrically laminated composite cantilever beam with and without a tip mass under harmonic base excitation. The base is subjected to both flapwise and chordwise excitations tuned to the primary resonances of the two directions and conditions of 2:1 autoparametric resonance. In the literature, the governing nonlinear equations of the same problem without tip mass have been derived using the extended Hamilton's principle. Extension is made in this study to include the effect of a tip mass on the response of the beam. The natural frequencies are obtained numerically using the diversity guided evolutionary algorithm (DGEA). Next, the multiple scales method is applied to determine the nonlinear response and stability of the system. A set of four first-order differential equations describing the modulation of the amplitudes and phases of interacting modes are derived for the perturbation analysis. For verification, the above equations are reduced to the special case of the cantilever beam without tip mass for comparison with existing results. Finally, the effect of the tip mass on the stability of the fixed points and on the amplitude of oscillation about the equilibrium points in both the frequency and force modulation responses is examined.

Occurrence and Prevention of Changes in the Chemical Structure of Natural Rubber Tire Tread Vulcanizates during Service

1970 ◽  
Vol 43 (5) ◽  
pp. 1215-1224 ◽  
Author(s):  
J. I. Cunneen ◽  
R. M. Russell
Keyword(s):  
Chemical Structure ◽  
Main Chain ◽  
Heavy Duty ◽  
Structural Alterations ◽  
The Road ◽  
Rubber Tire ◽  
Before And After ◽  
On The Road ◽  
The Stability ◽  
Made In

Abstract The chemical structure of the tread vulcanizate of heavy-duty tires has been investigated before and after service on the road, and after testing under conditions designed to induce tread-lift. Significant changes occurred. These included a marked reduction in the concentration of polysulfide crosslinks, and an increase in the amount of monosulfide crosslinks and main chain modification. Experiments with vulcanizates made in the laboratory indicated that the structural alterations in the tires were due to thermal anaerobic reactions caused by heat build-up, and that they resulted in a deterioration in some of the physical properties of the tread vulcanizate. The rate of desulfuration of ‘model’ polysulfides has been found to depend critically upon the nature of the vulcanization recipe. These novel findings point the way to improving the stability of vulcanizates used in the treads of tires and, consequently, tire performance.

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