ISSN:1122-8385    

DOI:10.1002/stc.4300030101

出版商:John Wiley&Sons, Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractAttention is focused on low‐damping‐rubber base‐isolators. Instead of thinking in terms of intelligent materials, this paper pursues the definition of conditions of behaviour which result intelligent in view of a coupling with an active control device (hybrid control). In particular, situations which show a chaotic behaviour of the dynamic response to external excitations are promising in terms of control efficiency. The regions of chaotic behaviour are identified by evaluation of the corresponding Lyapunov expo

ISSN:1122-8385    

DOI:10.1002/stc.4300030102

出版商:John Wiley&Sons, Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractThis paper deals with the sources of helicopter vibration and noise emissions. It shows and evaluates adaptive concepts to reduce them. The main reasons for these emissions are aerodynamic effects such as blade‐vortex‐inter action (BVI), aerodynamic hysteresis, and local transonic effects at the forward moving blade.After a review of conventional control concepts to reduce the vibrations and/or sound emissions, the possibilities to realise an adaptive rotorblade are explained.The understanding of the interaction between the aerodynamic sources and the resulting vibrations and noise is the basis of the design of optimal control conce

ISSN:1122-8385    

DOI:10.1002/stc.4300030103

出版商:John Wiley&Sons, Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractThis paper evaluates a hybrid feedback‐feedforward controller for vibration suppression. The synergy between the two types of controllers is pointed out. The feedforward control extends the bandwidth of the controller for steady state disturbances with a correlated reference, while the feedback control reduces drastically the impulse response of lightly damped structures, avoiding the problems associated with truncation. The hybrid controller does not require additional actuator and sensor. Two applications are presented in the area of vibration attenuation and precision pointing. In each case the theoretical advantage of the hybrid controller is confirmed by experiment

ISSN:1122-8385    

DOI:10.1002/stc.4300030104

出版商:John Wiley&Sons, Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractAn active vibration control system has been developed based upon analogue feedback and optical vibration sensing. Composite piezoelectric films have been deposited directly onto the cantilever to provide a means of actuation and micro‐positioning. The system operates such that unwanted vibrations in the cantilever are removed and yet it remains possible to deflect the cantilever statically or dynamically as required. Results are presented for such a syste

ISSN:1122-8385    

DOI:10.1002/stc.4300030105

出版商:John Wiley&Sons, Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractThe Besançon “Matériaux Intelligents” group is working on theoretical and practical aspects of design of dynamical stabilizers for realistic distributed systems. This paper is related to the modelling of an elastic multilayered plate including distributed piezoelectric actuators and a distributed electrical circuit. The derivation of the model is based on asymptotic methods. It is shown that the electrical circuit is a dynamical stabilizer for plate vibrations. An optimization procedure of circuit parameters is formulated and numerical results are disc

ISSN:1122-8385    

DOI:10.1002/stc.4300030106

出版商:John Wiley&Sons, Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractThis paper shows that, in some circomstances, conservative systems may possess complex zeros. The presence of these complex zeros seems to reduce the robustness of the control system with respect to parameter variations.

ISSN:1122-8385    

DOI:10.1002/stc.4300030107

出版商:John Wiley&Sons, Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractThe control of bending waves in a thin beam using a collocated feedback method is discussed with special reference to the case of a system comprising a displacement sensor and a force actuator. Control strategies involving vibration isolation (i.e. reducing wave transmission) and energy absorption (i.e. reducing scattered energy) are considered. Digital implementation is discussed and some results presented.

ISSN:1122-8385    

DOI:10.1002/stc.4300030108

出版商:John Wiley&Sons, Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractThe classical Rosenbrock's algorithm (based on the Gauss elimination method) forn‐dimensional linear time invariant state equation matrices is analysed and modernized. The method of orthogonal similarity reduction to block Hessenberg form is used to assure numerical stability. The updated version of the Rosenbrock's algorithm is then justified in a very easy way using properties of Krylov matrices. Additionally, this algorithm can be used to determine an equivalence transformation which converts ann‐dimensional linear state equation into a controllable form (or a time invariant one into an equivalent observable form). It is advantageous for big and medium size problems and can be easily parallelized. Numerical examples are presen

ISSN:1122-8385    

DOI:10.1002/stc.4300030109

出版商:John Wiley&Sons, Ltd    

年代:1996

数据来源: WILEY

摘要:

AbstractThe aim of the present paper is to investigate two strategies for the active control of plate vibrations, using distributed sensors and actuators (PVDF patches) working on a wide frequency band. The two strategies correspond to the two ends of a spectrum ranging from very robust/less efficient schemes (analog static output feedback) to less robust/very efficient schemes (here ‘frequency shaped LQG’).Both have been experimentally tested and have given successful attenuations; the efficiency of both approaches is demonstrated on sensor signals involved in the control loop as well as on radiated pressure measurements, which constitute an independent index of performance.It is shown that ‘frequency shaped LQG’ is a viable approach to feedback control of lightly damped structures, and that its robustness can be enhanced through a careful design.LQG is a model‐based method, and hence requires the modeling of the active structure. Two approaches are investigated in this paper: a finite element model and a identified model built from the experimentally measured transfer

ISSN:1122-8385    

DOI:10.1002/stc.4300030110

出版商:John Wiley&Sons, Ltd    

年代:1996

数据来源: WILEY