Papers by Keyword: Semi-Active Control

Abstract: A type of Magneto-Rheological Materials (MRMs) was prepared. The off-state viscosity and the shear stress of the MRMs were characterized and studied by an advanced rotational rheometer system. A kind of Self-Decoupling Magneto-rheological (SDMR) damper was established based on these MRMs. An intellectual isolation system for grid structures was obtained by integrating SDMR damper and isolation device. The seismic whiplash effect of the top bent frame column and space grid roof of the hydropower plant could be reduced. Furthermore, the half stable increment method was proposed as the semi-active strategy. The results indicated that the SDMR dampers used at the grid roof supports setting plate rubber bearings can significantly improve the vibration performance and energy dissipation structure roof isolation system in different seismic intensity. In addition, these SDMR dampers can effectively reduce the lateral slippage of the plate rubber, so as to avoid failure or damage of the isolation system because of the transfinite horizontal displacements. Compared with the conventional damper only in case of multiple earthquakes, the damping force and adjustable multiple of this SDMR damper have better adaptability, and this SDMR damper provides a higher safety factor.

Abstract: This contribution reviews the challenges in adaptive self-protection of structures. A proper semi-active control strategy can significantly increase structural ability to absorb impact-type loads and damp the resulting vibrations. Discussed systems constitute a new class of smart structures capable of a real-time identification of loads and vibration patterns, followed by a low-cost optimum absorption of the energy by structural adaptation. Given the always surging quest for safety, such systems have a great potential for practical applications (in landing gears, road barriers, space structures, etc.). Compared to passive systems, their better performance can be attributed to the paradigm of self-adaptivity, which is ubiquitous in nature, but still sparsely applied in structural engineering. Being in the early stages of development, their ultimate success depends on a concerted effort in facing a number of challenges. This contribution discusses some of the important problems, including these of a conceptual, technological, methodological and software engineering nature.

Abstract: In recent years, vibration damping strategies based on semi-active management of strain energy have attracted a large interest and were proven highly effective. However, most of published research considers simple one degree of freedom systems or study the same basic example (the first vibration mode of a cantilever beam) with the same control strategy. This contribution focuses on truss-frame nodes with controllable moment-bearing ability. It proposes and tests an approach that allows the control strategy to be extended to more complex structures and vibration patterns.

Abstract: Magneto-rheological (MR) damper is a semi-active control device, which takes advantage of both the reliability of passive devices and the adaptability of fully active control devices and is widely used on many kinds of machines and civil works. But there are some particular problems when the MRD is used on transmission tower-line system.This article is aimed to introduce the technological means to these problems such as :choose sant colony algorithm as the suitable semi-active control algorithm; consider adopting Self-Powered/Self-Sensing structure to Increased general OS stability;

Abstract: In this paper, a new control theory will be proposed for the purpose of enhancing vehicle ride performance. In the first step, a quarter car model with two DOF will be analyzed after which the classical semi-active control idea and a new control method will be built. Then a new hybrid control model based on body acceleration and classical one will be provided, after which the advantage of this controller will be studied. All the models that proposed will be accomplished through matlab/simulink. The outcome parameters of two types, namely, the body acceleration and the suspension deflection will be compared in frequency domain among three conditions which can be described as passive, classical semi-active control and hybrid control respectively. Then random excitation will be given as the road input to get power spectral density curves for further compare. Though the curves we can easily come into a conclusion that vehicle suspensions armed with this new controller will show the best ride properties which hold practical values.

Abstract: In this paper a new type of semi-active vibration absorber has been developed. The vibration absorber consists of mass block, cantilever beam, magnet lock system, vibration and distance sensors, controller and servo motor. The mass block is fixed on the tip of cantilever beam, and the control process is driven by a servo motor and a transmit gears. Portion of cantilever was cut in form of gear tracks, which can be driven by servo motor through transmit gear to regulate the length of the cantilever beam, and the natural frequency of absorber will also be regulated. After the mass locates in right position (i.e. the natural frequency of absorber is in assigned condition), the magnetic lock will clamp the cantilever beam. The design has the benefit of simplified control system, and extra unknown vibration modes will be averted. A fabrication prototype of the proposed semi-active vibration absorber is constructed and tested to demonstrate the application and modeling of the new cantilever beam damper. By performing the experimental work, the semi-active vibration control system is designed not only for reduce vibration level in resonant condition, but also considered for vibration attenuation in non-resonant conditions.

Abstract: 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.

Abstract: In the past, the semi-active control study generally is calculated based on the MATLAB numerical procedure, which cant achieve fine simulation. In this paper, to solve this problem, the finite element software ABAQUS is taken to be secondary development, a numerical simulation method of studying semi-active control is proposed. And the seismic response of a steel column is taken for the research. the numerical simulation analysis of the semi-active control is carried out. The results show that the control effect of the control method is significant, and the simulation result is clearly visible.

Abstract: This Paper focuses on the semi-active control application in the Mega-Sub Controlled Structure System (MSCSS) subjected to seismic excitation. The semi-active control devices, which are installed in the MSCSS between the mega-structure and sub-structure, were designed by using fuzzy neural network, and those semi-active control rules were optimized to enhance the control efficiency by using the genetic algorithm. A semi-active control problem of the MSCSS subjected to seismic excitation was investigated, the time history analyses under different seismic excitation, which like El Centro seismic wave and Taft seismic wave, were performed by using MATLAB. The calculation results demonstrate that the semi-active control combining the fuzzy neural network and genetic algorithm can clearly enhances the seismic performance of the MSCSS and it also provides an improved reduction in the dynamic response when compared to the passive control scheme.

Abstract: In this paper, the magneto-rheological damper is installed in the seat, using semi-active control theory and methods, dynamics mathematical model of the magneto-rheological damper seat is established, the fuzzy semi-active controller based on the magneto-rheological is designed, and then the simulation analysis on the system is completed by the software of MATAB/Simulink. The results of simulation show that the semi-active seat based on the magneto-rheological can markledly suppress the vibration acceleration and improve the ride comfort of the seat.