A modified chaotic oscillator with megastability and variable boosting and its synchronisation using contraction theory-based control which is better than backstepping and nonlinear active control

Pramana ◽  
2020 ◽  
Vol 94 (1) ◽  
Author(s):  
J P Singh ◽  
S Jafari ◽  
A J M Khalaf ◽  
V-T Pham ◽  
B K Roy
Keyword(s):  
Active Control ◽  
Chaotic Oscillator ◽  
Contraction Theory ◽  
Better Than

scholarly journals Active Control of Low-Frequency Noise through a Single Top-Hung Window in a Full-Sized Room

2020 ◽  
Vol 10 (19) ◽  
pp. 6817
Author(s):  
Bhan Lam ◽  
Dongyuan Shi ◽  
Valiantsin Belyi ◽  
Shulin Wen ◽  
Woon-Seng Gan ◽  
...  
Keyword(s):  
Active Control ◽  
Natural Ventilation ◽  
Active Noise Control ◽  
Low Frequency ◽  
Frequency Noise ◽  
Noise Mitigation ◽  
Single Top ◽  
Window Opening ◽  
Open Window ◽  
Better Than

The push for greater urban sustainability has increased the urgency of the search for noise mitigation solutions that allow for natural ventilation into buildings. Although a viable active noise control (ANC) solution with up to 10 dB of global attenuation between 100 Hz and 1000 Hz was previously developed for an open window, it had limited low-frequency performance below 300 Hz, owing to the small loudspeakers used. To improve the low-frequency attenuation, four passive radiator-based speakers were affixed around the opening of a top-hung ventilation window. The active control performance between 100 Hz and 700 Hz on a single top-hung window in a full-sized mock-up apartment room was examined. Active attenuation came close to the performance of the passive insulation provided by fully closing the window for expressway traffic and motorbike passing noise types. For a jet aircraft flyby, the performance of active attenuation with the window fully opened was similar to that of passive insulation with fully closed windows. In the case of low-frequency compressor noise, active attenuation’s performance was significantly better than the passive insulation. Overall, between 8 dB and 12 dB of active attenuation was achieved directly in front of the window opening, and up to 10.5 dB of attenuation was achieved across the entire room.

Research of the Piezoelectric Composite Active Control

2014 ◽  
Vol 1030-1032 ◽  
pp. 1513-1516
Author(s):  
Kun Huang ◽  
Wei Cai Peng ◽  
Zhi Xiong Huang ◽  
Min Xian Shi ◽  
Guang Bing Wan
Keyword(s):  
Active Control ◽  
Cantilever Beam ◽  
Pid Control ◽  
Piezoelectric Ceramic ◽  
Impact Force ◽  
Stopping Time ◽  
Piezoelectric Composite ◽  
Control Coefficient ◽  
Control Change ◽  
Better Than

Instantaneous signal and alternating signals are as driven signals, using PID control, change control coefficient P's size, The stopping time of impact force under instantaneous signal with the piezoelectric ceramic content increases, the stopping time is reduced; after applying active control, the stopping is shorter than that is not applied. After applying the alternating signal to force the cantilever beam, the driving effect of the ceramic sheet is located in a cantilever position A, B, C, the effect of C under controlling is at best. The effect of two driven ceramic sheets is better than that of three driven ceramic sheets, the best control position is B+C.

The Effects of Nested Texture on a Landing-Judgment Task

1988 ◽  
Vol 32 (2) ◽  
pp. 10-14 ◽  
Author(s):  
Kimberly A. Reardon
Keyword(s):  
Active Control ◽  
Judgment Task ◽  
Display Type ◽  
High Fidelity ◽  
Visual Displays ◽  
Control Task ◽  
Pilot Performance ◽  
Judgment Study ◽  
Better Than

Nested texture can be described as smaller units embedded within larger units or forms within forms (Gibson, 1966). This is reflected in real scenes, e.g., as one moves toward a surface the eye resolves more detail. With the advent of high-fidelity simulators we can now generate a hierarchy of texture patterns that emerge as a function of altitude, but how this affects pilot performance is unclear. This study examined the effect of nested texture with four types of displays in a landing-judgment task. Subjects viewed a simulated landing approach to a runway which stopped in “mid air” and were asked to indicate where they would land if they continued on the same path. Results show that when texture was nested as a function of altitude, performance was not significantly better than when texture was constant throughout the trial. Display type affected performance with subjects perceiving their aimpoint further down the runway as complexity of the texture increased. The landing-judgment study should be followed up with an active-control task before recommendations for visual displays are made.

Semi-Active Control on Stay Cable Vibration Based on Fuzzy Logical Theory

2010 ◽  
Vol 163-167 ◽  
pp. 2815-2818
Author(s):  
Zhi Rong Xiao
Keyword(s):  
Active Control ◽  
Passive Control ◽  
Control Method ◽  
Fuzzy Controller ◽  
Simulation Analysis ◽  
Mr Damper ◽  
Stay Cable ◽  
Logical Theory ◽  
Better Than ◽  
Fuzzy Logical

A new method of semi-active control on cable-MR system based on fuzzy logical theory in this article is presented. In the method, the voltage to drive MR damper is determined by fuzzy controller, which avoids the difficulty of calculating the voltage from the strong nonlinear MR model. In order to testify the effectiveness of the proposed method, the simulation analysis to a typical cable is made and its results are compared to the passive control (passive-on, passive-off) of MR and active control (LQR). The conclusion is that the operation of fuzzy control method is simple and practical. Its effect is better than the passive methods, but is a little worse than LQR.

scholarly journals Active Tuned Mass Dampers for Control of Seismic Structures

2020 ◽  
Vol 19 ◽  
Keyword(s):  
Active Control ◽  
Structural Control ◽  
Structural Vibrations ◽  
Tuned Mass Dampers ◽  
Strong Earthquakes ◽  
Future Studies ◽  
Mass Damper ◽  
Strong Winds ◽  
Error Method ◽  
Better Than

Structural control has been implemented to major structures that are exposed to excitations which have random vibration behavior including strong winds, traffics and especially ground accelerations resulting from strong earthquakes. It is possible to apply passive and active control methods. In passive, structures are controlled via additional mechanical components, while and external force generating by a powered motor is needed for active control. In the practice of this study, active tuned mass dampers (ATMDs) are used to reduce vibration and responses of structures. The parameters of Proportional-Integral-Derivative (PID) type controllers used in ATMD was found via trial-error method, while mechanical properties of mass damper are optimized via metaheuristic algorithm called Jaya Algorithm. The results were compared with passive tuned mass damper (TMD) and uncontrolled structure. The tuned ATMD is effective to reduce structural vibrations better than TMD. In future studies, both mechanical and controller parameters can be optimized via metaheuristic algorithms.

Comparative study of synchronization methods of fractional order chaotic systems

2016 ◽  
Vol 5 (3) ◽  
Author(s):  
Ajit K. Singh ◽  
Vijay K. Yadav ◽  
S. Das
Keyword(s):  
Active Control ◽  
Fractional Order ◽  
Chaotic Systems ◽  
Control Method ◽  
Salient Feature ◽  
Backstepping Method ◽  
Backstepping Approach ◽  
Active Control Method ◽  
Methods Numerical ◽  
Better Than

AbstractIn this article, the active control method and the backstepping method are used during the synchronization of fractional order chaotic systems. The salient feature of the article is the analysis of time of synchronization between fractional order Chen and Qi systems using both the methods. Numerical simulation and graphical results clearly exhibit that backstepping approach is better than active control method for synchronization of the considered pair of systems, as it takes less time to synchronize while using the first one compare to second one.

Study on Improved Fuzzy Semi-Active Control for the Cable-stayed with MR Damper by Finite Element Simulation

2014 ◽  
Vol 926-930 ◽  
pp. 1429-1435
Author(s):  
Zheng Xin Zhang ◽  
Qian Hui Liu
Keyword(s):  
Finite Element ◽  
Active Control ◽  
Control Strategy ◽  
Control Method ◽  
Mr Damper ◽  
Scaling Factor ◽  
Element Simulation ◽  
Active Control Strategy ◽  
Active Control Method ◽  
Better Than

An improved fuzzy semi-active control method forparametric vibration of the cable-stayed with MR damper was proposed. The parametervibration control of the cable M22 and the cable M13 of the Hongshuihecable-stayed Bridge was studied. The results show that the effect of theimproved fuzzy semi-active control strategy was better than that of the fuzzysemi-active control strategy. In addition, the proposed fuzzy semi-activecontrol strategy does not need to debug the scaling factor of input variablesand output variables and the MR damper required lower voltages. Therefore，theproposed method makes the fuzzy control more intelligent.

Treatment of severe depression with paroxetine

1993 ◽  
Vol 8 (S1) ◽  
pp. 21s-23s ◽  
Author(s):  
J Tignol
Keyword(s):  
Active Control ◽  
Outcome Measures ◽  
Severe Depression ◽  
Hospitalised Patients ◽  
Significant Difference ◽  
Hamd Score ◽  
Meta Analyses ◽  
Better Than

SummaryMeta-analyses of 417 patients diagnosed either prospectively (316 US patients) or retrospectively (101 European patients) as suffering from melancholia according to DSM III criteria have shown that paroxetine was significantly better than placebo with respect to all outcome measures. There was no significant difference between active control and placebo in these analyses. In a group of 216 severely depressed hospitalised patients with a HAMD score of 25 or more, paroxetine was as effective as active control.

Time and Latitude in South Africa

1972 ◽  
Vol 1 ◽  
pp. 27-38
Author(s):  
J. Hers
Keyword(s):  
South Africa ◽  
Cape Town ◽  
Astronomical Observations ◽  
Royal Observatory ◽  
The Republic ◽  
Astronomical Determination ◽  
Limited Accuracy ◽  
Better Than

In South Africa the modern outlook towards time may be said to have started in 1948. Both the two major observatories, The Royal Observatory in Cape Town and the Union Observatory (now known as the Republic Observatory) in Johannesburg had, of course, been involved in the astronomical determination of time almost from their inception, and the Johannesburg Observatory has been responsible for the official time of South Africa since 1908. However the pendulum clocks then in use could not be relied on to provide an accuracy better than about 1/10 second, which was of the same order as that of the astronomical observations. It is doubtful if much use was made of even this limited accuracy outside the two observatories, and although there may – occasionally have been a demand for more accurate time, it was certainly not voiced.

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