检索结果-内蒙古大学图书馆

smart structures and materials 1994: mathematics and control in smart structures

作者： Stech, Daniel J. Frank J. Seiler Laboratory U.S. Air Force Academy CO United States

Solution of nonlinear optimal control problems on analog parallel networks is proposed. Recurrent neural networks whose dynamic equations have a Lyapunov function are developed. Such circuits relax to an equilibrium which is the minimum of the Lyapunov function. Nonlinear optimal control problems are formulated in terms of a Lyapunov function and thus are solved using the recurrent networks. Convergence for linear and nonlinear classes of problems is considered. The method is demonstrated by developing and simulating a network to solve a nonlinear vibration problem. Simulation results demonstrate solution times are accurate and extremely fast. Solution times are shown to be independent of the size of the problem. © 1994 SPIE.

关键词： Lyapunov functions

来源：评论

学校读者我要写书评

暂无评论

Parametric control of structural vibrations via piezoelectric materials shunted with adaptive circuits

Parametric control of structural vibrations via piezoelectri...

引用

smart structures and materials 1994: mathematics and control in smart structures

作者： Wang, K.W. Yu, W.K. Lai, J.S. Mechanical Engineering Department Pennsylvania State University University ParkPA16802 United States

A new structural vibration control concept, using piezoelectric materials shunted with real-time adaptable electrical networks, has been developed. The variable resistance and inductance in an external RL circuit are used as control inputs. Novel energy-based parametric control schemes are created to reduce the total system energy (the main structure mechanical energy plus the electrical-mechanical energy of the piezoelectric material and electrical circuit) while minimizing the energy flowing into the main structure. The performances of the controllers are examined through computer simulations on a beam example. It is shown that the structure energy level and vibration amplitude can be suppressed effectively. © 1994 SPIE.

关键词： Piezoelectric materials

来源：评论

学校读者我要写书评

暂无评论

SHAPE OPTIMIZATION OF DISTRIBUTED SENSORS AND ACTUATORS FOR smart STRUCTURE control

SHAPE OPTIMIZATION OF DISTRIBUTED SENSORS AND ACTUATORS FOR ...

引用

smart structures and materials 1994 Conference - smart structures and Intelligent Systems

作者： ZHUANG, Y BARAS, JS UNIV MARYLAND INST SYST RESCOLLEGE PKMD 20742

ISBN: (纸本)0819414859

We describe a design technique for optimal control in active structural vibration damping using smart materials. The vibration of a cantilever beam is stabilized by feedback the weighted integration of vibration velocity in the closed loop system through the application of distributed sensors and actuators made of smart materials. We model the beam by the Timoshenko beam model embedded with the distributed sensors and actuators to account for the shear and inertial effects on the structures. We propose an algorithm to find the optimal placement of the actuators and sensors so as to maximize the damping effect. An objective functional is defined based on the vibration energy of the system. The optimal shapes of the sensor and actuator are determined through minimizing the energy functional of the beam over the admissible shape function space subject to certain constraints. This approach can be generalized to cases of plate damping and active control of more complicated smart structures as well.

关键词： FLEXIBLE STRUCTURE control DISTRIBUTED control ADAPTIVE structures SENSORS ACTUATORS smart materials

来源：评论

学校读者我要写书评

暂无评论

smart dynamic system design: An integrated approach

Smart dynamic system design: An integrated approach

引用

smart structures and materials 1994: mathematics and control in smart structures

作者： Carpenter, M.J. Skelton, R.E. Space Systems Control Laboratory 1293 Potter Engineering Center Purdue University West LafayetteIN47907-1293 United States

A dynamic system with satisfactory performance generally consists of a mechanical system (the plant) and a controller that drives the mechanical system to meet certain performance requirements. Traditionally the control engineer designs the controller only after the plant design is completed. This two-step approach to plant and controller design does not provide the best system design because the dynamics of the plant and the dynamics of the controller often oppose each other. An integrated design unifies the disciplines of structure design and controller design to achieve control performance objectives that might not otherwise be achieved by the two-step design process. This paper presents an application of the iterative system equivalent optimal mix algorithm to perform a smart design of a nine-member truss substructure and its accompanying controller. The objective of the design algorithm is to reduce the amount of energy used by the controller to maintain control performance, subject to the structure design constraints. Two unique features of the algorithm are that each iteration of the design problem is stated as a convex quadratic programming problem, and the control effort monotonically convergences to its final value. © 1994 SPIE.

关键词： controllers

来源：评论

学校读者我要写书评

暂无评论

Distributed fuzzy control of a flexible structure

Distributed fuzzy control of a flexible structure

引用

smart structures and materials 1994: mathematics and control in smart structures

作者： Wiegand, James R. Helferty, John J. Temple University Department of Electrical Engineering College of Engineering PhiladelphiaPA19122 United States

This paper details the design and implementation of a fuzzy controller for the ASTREX flexible space structure model. The novel control strategy is the first attempt to apply fuzzy logic to the feedback control of a large scale structure system. The ASTREX system at Edwards Air Force Base consists of three flexible trusses, joined to a flexible base system and culminating in a line-of-sight positioning instrument, smart control of each truss is accomplished by three axial piezoelectric actuators on each truss, and six bending sensors. Two sensors are grouped with each actuator, in colocated and nearly colocated positions. control system design procedure is detailed. The open-loop system is simulated to determine the appropriate universes of discourse for the input fuzzy membership functions. Output magnitude of the controller is determined by the dynamic range of piezoelectric actuators. The architectural design of fuzzy logic controllers is currently an open issue. There exist many different forms of fuzzy logic controllers, and the performance characteristics of each type can not generally be determined a priori. Results of preliminary investigations into the type of fuzzy logic controller necessary for efficient control of flexible structures are shown using simulations involving partial models of one beam of the ASTREX flexible satellite. © 1994 SPIE.

关键词： Flexible structures

来源：评论

学校读者我要写书评

暂无评论

ANALYTICAL AND EXPERIMENTAL STUDIES OF smart materials AND structures INCORPORATING EMBEDDED PIEZOELECTRIC ACTUATORS AND FIBEROPTIC SENSORS

ANALYTICAL AND EXPERIMENTAL STUDIES OF SMART MATERIALS AND S...

引用

smart structures and materials 1994 Conference - smart structures and Intelligent Systems

作者： FAIRLES, R GLOWASKY, B MCDONNELL DOUGLAS AEROSP E ADV MAT & STRUCTST LOUISMO 63166

ISBN: (纸本)0819414859

The thrust of this research has been to develop powerful models for characterizing sensor and actuator behavior, and to construct demonstration articles for assessing and quantifying the performance of advanced embedded actuators and sensors. Powerful finite elements have been developed to model the sensor and actuator behavior for use in designing smart systems. The capability exists to accurately model fiberoptic sensors, piezoelectric material behavior, and shape memory alloy material behavior in both static and dynamic applications. These finite elements were written for use with the ABAQUS computer code. Real-time data interaction with the code allows active control simulations to be conducted. Existing control theories have been used to analytically simulate response control of randomly excited structures. In addition, both thermoset and thermoplastic composite structures with embedded piezoelectric actuators were fabricated. These structures will be used as benchmarks to evaluate our smart structure manufacturing capabilities. The manufacturing methods presented here have addressed the issues of sensor / actuator survivability, sensor / actuator integration, and process conditioning. Finally, the results for all tests are qualified and compared, and the implications for their relationship to future platforms are discussed.

关键词： Actuators Sensors smart structures Shape memory alloys Manufacturing Fiber optics sensors Composites smart materials control systems Systems modeling

来源：评论

学校读者我要写书评

暂无评论

Adaptive processing for non-contact inductive smart structure sensor interrogation system using hierarchical neural networks

Adaptive processing for non-contact inductive smart structur...

引用

smart structures and materials 1994: mathematics and control in smart structures

作者： Spillman, W.B. Durkee, S. Kuhns, W.W. BFGoodrich Aerospace Division Simmonds Precision Aircraft Systems VergennesVT05491 United States

A method of non-contact interrogation of electronic and opto-electronic systems embedded within composite materials has been recently demonstrated. The method is based upon inductive coupling between external and embedded coils etched on thin electronic circuit cards. Measurements at two frequencies allow the coil separation and the value of an electrical parameter of interest to be determined. An investigation into the practicality of utilizing neural processing to calculate these parameters was carried out. The final system utilized a hierarchical architecture of three neural networks combined with an adaptive measurement of voltage at a frequency determined by the coil separation calculated by one of the neural networks. The system was implemented using custom electronics and a PC laptop computer. A description of the design process is given together with system performance parameters. © 1994 SPIE.

关键词： Inductive sensors

来源：评论

学校读者我要写书评

暂无评论

SPURIOUS NONMINIMUM-PHASE ZEROS IN MODELS OF smart structures

SPURIOUS NONMINIMUM-PHASE ZEROS IN MODELS OF SMART STRUCTURE...

引用

smart structures and materials 1994 Conference - smart structures and Intelligent Systems

作者： HENRICH, EA GILLIS, JT OCONNOR, JM AEROSP CORP LOS ANGELESCA 90009

ISBN: (纸本)0819414859

This paper addresses the implications of spurious nonminimum phase zeros for design of control systems with noncollocated sensors and actuators. The relationship between the finite- element model and the control system model is examined in detail, with particular emphasis on the physical analogies of nonminimum phase zeros in the finite-dimensional representation of the system. Finite element models of constrained systems may be used to determine which zeros are spurious. Synthesis of accurate transfer functions is demonstrated using the idea of constrained modes. By considering the infinity norm of the undermodelling, the exact residue model even with spurious nonminimum phase zeros is the preferred model for control system design.

关键词： Systems modeling Sensors Finite element methods Actuators control systems design Chemical elements Finite difference methods smart structures Differential equations Matrices

来源：评论

学校读者我要写书评

暂无评论

SURFACE, TRANSFORMS AND INTERFACES - THE smart DIRECTION FOR POLYMER SCIENCE

引用

SYNTHETIC METALS 1994年第1-3期67卷 63-70页

作者： CLARK, DT Research Unit for Surfaces Daresbury Laboratory Warrington Cheshire WA4 4AD UK

Interface science of polymer/metal semiconductor ceramic interfaces has to date focused largely on model quasi two-dimensional systems and yet the long-term future is their role in three-dimensional environmentally adaptive, self-repairing 'smart' materials systems, that start to provide a genuine mimic of nature's 'composite' materials systems. It is becoming clear that polymer science and technology will play a pivotal role in the emerging 'chemistry direct to shapes' era where molecular level design, synthesis and assembly of the spatially resolved 'active' materials systems of the future will bypass many of the issues of incommensurate engineering associated with bolt-on actuators, sensors, etc., currently envisaged. The issues of massively parallel information processing to provide a knowledge response mode will also hinge on developments in polymer science and the molecular level control of interface structures. The core competencies required are already becoming apparent and are briefly reviewed in this paper.

关键词： SURFACE INTERFACES smart DIRECTION

来源：评论

学校读者我要写书评

暂无评论

smart CERAMICS FOR BROAD-BAND VIBRATION control

引用

JOURNAL OF INTELLIGENT MATERIAL SYSTEMS AND structures 1994年第5期5卷 673-677页

作者： KUMAR, S BHALLA, AS CROSS, LE [o_1]Materials Research Laboratory The Pennsylvania State University University Park PA 16802 [o_2]Materials Research Laboratory The Pennsylvania State University University Park PA 16802 [o_3]Materials Research Laboratory The Pennsylvania State University University Park PA 16802

The broadband control of compliance coefficient S33 of a hard ceramic has direct applications in active vibration control. A collocated smart system consisting of ceramic sensor, actuator and a feedback amplifier is developed with 3.5 kHz bandwidth of compliance control without using filter in the feedback circuit. It is found that modified lead titanate with very low planar coupling coefficient k(p) is most suited as a sensor material for this type of system. The requirements of the feedback amplifier for such a system are discussed and an amplifier design presented. The bandwidth of compliance control is experimentally determined by bench tests using a B and K shaker.

关键词： Ceramic materials

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：