检索结果-内蒙古大学图书馆

Sensor/actuator optimal design for active vibration control of shell structure

JOURNAL OF INTELLIGENT MATERIAL SYSTEMS AND structures 2000年第11期11卷 848-856页

作者： Kim, SJ Hwang, JS Mok, J Seoul Natl Univ Dept Aerosp Engn Seoul 151742 South Korea

In this paper, a distributed sensor and actuator are designed for the active vibration control of shell structure. To prevent the adverse effect of spillover, distributed modal sensor/actuator system is established by optimizing the electrode pattern and the lamination angle (if poly vinylidene fluoride (PVDF). Finite element programs are developed to consider the curved structures integrated with PVDF sensor and actuator. The nine-node Mindlin shell element is used for finite element discretization. The electrode pattern and the lamination angle of PVDF sensor/actuator are optimized using genetic algorithm. The sensor is designed to minimize the observation spillover, and actuator is designed to minimize the system energy of the control modes under a given initial condition. For the verification of the design, numerical simulation and real-time vibration control experiment of the integrated smart structure are performed using discrete LQG method as the control law. A singly curved cantilevered smart shell structure integrated with distributed modal sensor/actuator for the suppression of the first and second modes is manufactured for the experiment. The vibration suppressions of control modes are successfully achieved as expected.

关键词： Shells (structures)

来源：评论

学校读者我要写书评

暂无评论

Optimum vibration control of CFRP sandwich beam using electro-rheological fluids and piezoceramic actuators

引用

smart materials & structures 2000年第1期9卷 121-125页

作者： Fukuda, T Takawa, T Nakashima, K Osaka City Univ Osaka Japan Setsunan Univ Dept Ind & Syst Engn Neyagawa Osaka 5728508 Japan Matsushita Elect Components Ltd High Frequency Prod Div Dept Engn Ono Gifu 5010598 Japan

In the present study, the vibration control of a hybrid smart composite beam actuated by both electro-rheological fluids (ERFs) and piezoceramic actuators is investigated. A carbon fiber reinforced plastics beam, including interleaved ERF and bonded piezoceramics, is prepared and tested under sinusoidal external excitations. Four kinds of feedback control strategies for both ERF and piezoceramic actuators are adopted in order to suppress the deflection at the free end of the cantilevered composite beam. The optimum combination of these control strategies for two types of actuators is discussed when the two actuators operate simultaneously.

关键词： Sandwich structures

来源：评论

学校读者我要写书评

暂无评论

smart materials and structures and their application in aerospace

引用

Stahlbau 2000年第7期69卷 556-567页

作者： Boller, Christian Chefingenieur Flugzeugstruktur Daimler-Chrysler Aerosp. M. 81663 München Germany

This paper is an overview regarding current activities being related to the integration of sensing, actuation and control elements into aerospace materials and structures, which is considered to be termed `smart' internationally and Adaptronics especially in Germany. Starting with actually available technologies, potential applications will be described such as primarily condition monitoring (e.g. damage), shape control especially related to aerodynamic profiles and vibration damping. Finally some ideas will be shared regarding requirements for realizing smart materials and structures beyond the laboratory stage.

关键词： Steel structures

来源：评论

学校读者我要写书评

暂无评论

Dynamic characteristics of magneto-rheological fluid damper

Dynamic characteristics of magneto-rheological fluid damper

引用

smart structures and materials 2000: Damping and Isolation

作者： Sunakoda, Katsuaki Sodeyama, Hiroshi Iwata, Norio Fujitani, Hideo Soda, Satsuya Sanwa Tekki Corp Tokyo Japan

Two kinds of Magneto-rheological fluid damper (MRF damper) have been designed and manufactured. One has a nominal capacity of 2 kN and the other 20 kN. A bypass flow system is adopted for both dampers and each has the same capacity of electromagnet attached to the bypass portion. The effective fluid orifice is the rectangular space and the magnetic field is applied from the outside. A test was performed by applying different magnetic fields to the orifice portion of the rectangular space. The damping force and the force-displacement loop were evaluated. The test results yielded the following: 1) Two type's of dampers functioned by using one unit of the electromagnet under an appropriate electrical current control. 2) The magnitude of the damping force depends on the input magnetic field, but it has an upper limit. 3) Without an applied magnetic field, the MRF damper exhibits viscous-like behavior, while with a magnetic field it shows friction-like behavior. A mechanical model of the damper is estimated by taking account of the force-displacement loop. It is clarified that MRF dampers provide a technology that enables effective semi-active control in real building structures.

关键词： Vibration control

来源：评论

学校读者我要写书评

暂无评论

Investigation of piezoelectric smart composites using a coupled piezoelectric-mechanical model

Investigation of piezoelectric smart composites using a coup...

引用

41st AIAA/ASME/ASCE/AHS/ASC structures, Structural Dynamics, and materials Conference and ExhibitAIAA/ASME/AHS Adaptive structures ForumAIAA Non-Deterministic Approaches ForumAIAA Space Inflatables Forum

作者： Zhou, Xu Chattopadhyay, Aditi Thornburgh, Rob Arizona State Univ Tempe AZ United States

A two-way piezoelectric-mechanical coupled theory is used to investigate the multiple field interactions of composite laminates with surface-bonded piezoelectric actuators and sensors. A higher order electrical potential field is used to accurately describe the nonuniform distribution of electric potential through the thickness of piezoelectric layers. A higher order laminate theory is used to describe the displacement fields of both composite laminate and piezoelectric layers to accurately model transverse shear deformation which is significant in moderately thick constructions. A finite element model is developed to implement the theory. The results obtained using this coupled theory are compared with those obtained using an uncoupled theory. Numerical results indicate that the thickness ratio of piezoelectric layer to plate structure is a critical parameter that determines the significance of coupling effects. The coupled piezoelectric-mechanical theory is capable of accurately modeling the characteristics of thick piezoelectric layers. Furthermore, the effects on multiple actuators, sensors and control authority due to the two-way coupling are also studied.

关键词： Laminated composites

来源：评论

学校读者我要写书评

暂无评论

Three degrees-of-freedom adaptive-passive isolator for launch vehicle payloads

Three degrees-of-freedom adaptive-passive isolator for launc...

引用

smart structures and materials 2000 - Industrial and Commercial Applications of smart structures Technologies

作者： Khorrami, Farshad Rastegar, Jahangir Erwin, R.Scott OmniTek Research & Development Inc Melville United States

Payloads (e.g., spacecrafts) are attached to launch vehicles by structural adapters known as Payload Adapter Fittings (PAF). The adapters are substantially rigid;therefore, the launch vehicle vibration is transmitted without isolation to the payloads. The payload cost includes a substantial component for provision to withstand the severe launch vibration environment. In this paper, a novel three degree-of-freedom isolation system built in the footprint and within the existing PAFs is presented. The vibration isolator consists of a mechanical constraining mechanism that prevents the rotation of the payload (i.e., the upper ring of the PAF) relative to the launch vehicle (i.e., the lower ring of the PAF) in both rocking rotation and rotation about the long axis of the launch vehicle. The above rotational motion restraining mechanism would therefore only allow axial (longitudinal) and lateral vibration of the payload relative to the launch vehicle. The second major component of the system consists of isolation components that are used to reduce vibration in the latter two directions, i.e., in the axial and the lateral directions. The proposed isolating payload adapter fitting also has a stand-alone thrust-support preload adjustment component that adjusts for the varying quasi-static acceleration seen in different flight regimes in a passive-adaptive control mode. The advocated isolation system is structurally modular and parametrizable such that a range of launch vehicle platforms could be accommodated. Through the utilization of the advocated isolating payload adapter fitting, a fifty percent reduction in vibration transmission is achieved at 10 Hz in the axial direction and 20 Hz in the lateral directions. A 40 db reduction is achieved at frequencies above 100 Hz. Active actuating elements may easily be included in the proposed design to attain an active isolation unit.

关键词： Intelligent structures

来源：评论

学校读者我要写书评

暂无评论

Vibration control of a flexible beam with integrated actuators and sensors

引用

smart materials & structures 2000年第6期9卷 932-939页

作者： Manning, WJ Plummer, AR Levesley, MC Univ Leeds Sch Mech Engn Leeds LS2 9JT W Yorkshire England

The use of system identification to determine linear Auto Regressive Moving Average eXogenous inputs (ARMAX) models for smart structures has been scarcely reported in the literature. However, these models can be used as a basis for a Linear discrete-time controller design. This work presents a smart structure vibration control scheme developed using an ARMAX model of the structure and compares its performance to an empirically designed velocity feedback controller. The smart structure is comprised of piezoceramic (such as PZT) actuators and strain gauge sensors attached to a cantilever beam and interfaced to a PC, which provides the control software platform. System identification is carried out in three phases: data collection, model characterization and parameter estimation. Input-output data are collected by stimulating the piezoactuators with a bipolar square wave signal and monitoring the strain gauge response. The model is characterized with second-order plant dynamics and a least-squares estimation algorithm calculates the model parameters. The controller is designed using pole placement to achieve the desired closed-loop response. The ARMAX model is used to calculate the pole placement controllers by solution of the Diophantine equation for the prescribed closed-loop pole positions. Results show that the pole placement controller can match the performance of a velocity feedback controller and maintain this performance when the sampling rate is greatly reduced.

关键词： Intelligent structures

来源：评论

学校读者我要写书评

暂无评论

Distributed arithmetic implementation of multivariable controllers for smart structural systems

引用

smart materials & structures 2000年第4期9卷 402-412页

作者： Yuan, LF Sana, S Pottinger, HJ Rao, VS Univ Missouri Dept Elect & Comp Engn Rolla MO 65409 USA Univ Missouri Intelligent Syst Ctr Rolla MO 65409 USA

smart structural systems require the electronic control systems which are integrated into the structures to be small, light weight and power-efficient. The field programmable gate array (FPGA) is a good platform to implement such controllers. In our previous work, FPGA-based digital controllers were built and tested on a simple structural system. In order to implement multivariable controllers, the hardware resources for FPGA-based architecture need to be further reduced. Distributed arithmetic (DA) has long been proven to be a very efficient means to mechanize computations that are dominated by inner products involving constant multiplicand. The computational requirements of the smart structural controllers match this type very well. In this paper various DA structure controllers are designed and results are compared with multiply-and-accumulate structure controllers. Single- and multi-variable controllers are implemented and tested on a cantilevered beam.

关键词： Multivariable control systems

来源：评论

学校读者我要写书评

暂无评论

Cryocooler disturbance reduction with single and multiple axis active/passive vibration control systems

Cryocooler disturbance reduction with single and multiple ax...

引用

smart structures and materials 2000: Damping and Isolation

作者： Flint, Eric Flannery, Patrick Evert, Michael Anderson, Eric CSA Engineering Mountain View United States

Cryocoolers are well known sources of harmonic disturbance forces. In this paper two miniaturized, add-on, vacuum compatible, active vibration control systems for cryocoolers are discussed. The first, called VIS6, is an active/passive isolation hexapod and has control authority in all six degrees of freedom. This capability is desirable when reduction of all cryocooler disturbance loads, including the radial loads, is required. Each of the six identical hexapod struts consists of a miniature moving coil electromagnetic proof mass actuator, custom piezoelectric wafer load cell, viscoelastic passive isolation stage, and axial end flexures. The first five disturbance tones are reduced over a bandwidth of 250 Hz using a filtered-x least mean square algorithm. Load reductions of 30-40 dB were measured both axially and radially. The second system, called VRS1, is a pure active control system designed to reduce axial expander head disturbance loads. It works on the basis of a counter-force developed from an electromagnetic proof mass actuator. Error signals are provided from a commercial accelerometer to a standalone digital signal processor, on which a filtered-x least means square control algorithm is implemented. Over the 500 Hz control bandwidth, the 11 disturbance tones were reduced on between 14 to 40 dB.

关键词： Intelligent structures

来源：评论

学校读者我要写书评

暂无评论

Damping and isolation of the GHM mini-oscillators

Damping and isolation of the GHM mini-oscillators

引用

smart structures and materials 2000: Damping and Isolation

作者： Liao, Wei-Hsin Chinese Univ of Hong Kong Shatin Hong Kong

Golla-Hughes-McTavish (GHM) method has been shown to be an effective approach to model viscoelastic materials (VEMs). In the GHM model, a mini-oscillator has been used as the mechanical analogy to illustrate the relation of GHM parameters. However, the GHM mini-oscillators have not been studied in depth so far. In this paper, the damping and isolation characteristics of this two degree-of-freedom mini-oscillator are analyzed. Those characteristics are crucial to the effectiveness and limitations of the passive and hybrid (active-passive) vibration suppression techniques employing VEMs. Under harmonic excitations, the corresponding nondimensional relationships among parameters are derived. The transmissibility due to force and base excitations is investigated with respect to various parameters. The damping ability of the mini-oscillator is also evaluated. For those critical points and special cases, their conditions are identified and discussed. Several unique distinctions are observed when compared to previous studies on vibration absorbers and isolators. The analysis results of this research provide more understanding and physical insight to designers when considering VEM-based configurations including passive and hybrid systems for the purpose of vibration isolation and control.

关键词： Vibration control

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：