Design Of Vibration Control System Research Articles

Adaptive parameter identification of Bouc-wen hysteresis model for a vibration system using magnetorheological elastomer

The Bouc–wen hysteresis model has been widely used to design systems using magnetorheological (MR) materials. However, the model parameters cannot be perfectly determined due to the magnetic-field dependency and unmeasurable states. In this study, a novel adaptive parameter identification method is proposed for a model consisting of three components: an estimated model, a hysteresis observer, and adaptive algorithms. While the estimated model refers to the experimental data and adjusts the parameters directly to their actual values, the hysteresis observer is constructed to portray the unmeasurable hysteretic force that is based on the observer dynamic and misalignment. The proposed adaptive algorithms updated the parameters to actual values based on stability and adaptation theory. The Bouc–wen model, whose parameters were determined by the proposed method, captured the MR elastomer (MRE) characteristics well at different frequencies, amplitudes, and magnetic field strengths. The method was further studied to determine the parameters of a nonlinear vibration structure equipped with an MRE-based isolator. Asymptotic stability in response tracking and robustness in dynamic excitation were demonstrated using this theory. The method was characterized by fast convergence and simple calculations that facilitate the design of vibration control systems with uncertain parameters and hysteretic state. A comparison between the simulation and experimental results proved the effectiveness of the proposed method.

LMI 기법에 의한 제진 시스템 최적 설계

구조물의 진동에 의해 유발되는 사용성, 안정성 저하를 방지하고, 성능을 개선하기 위하여 많은 진동제어시스템이 사용되어 왔다. 제어기 설계가 H2-norm, H∞-norm 으로 분리되어 독립적으로 이루어지다가 LMI 기법에 의하여 보다 효율적인 제어기 설계가 가능하게 되었다. 본 연구에서는 관심지점의 구조물 응답을 특정한 값 이하로 보장한 상태에서 제진장치 구동에 필요한 변수를 최소 화하는 제어알고리듬을 개발하여 능동형뿐만 아니라 수동형제진장치에도 적용하는 방안을 제시하였다. 관심지점의 구조물 응답의 제한은 요구 등가감쇠비와 H∞-norm을 연계하여 구속조건으로 설정하고 목적함수는 제진장치의 이송거리 또는 댐퍼 용량은 H2-norm으 로 표현하는 혼합제어를 구성하였다. 본 연구에서 제안된 혼합제어 기법을 능동질량감쇠기와 등가치환 점탄성 댐퍼가 설치된 구조물에 적용하여 수치적으로 검증하였다. 수치해석결과, 혼합제어문제를 LMI표준형으로 전환하면 능동형, 수동형 제진장치 설계를 보다 용이하게 적용 가능함을 알 수 있었다.

Integrated Design of Hybrid Interstory-Interbuilding Multi-Actuation Schemes for Vibration Control of Adjacent Buildings under Seismic Excitations

The design of vibration control systems for the seismic protection of closely adjacent buildings is a complex and challenging problem. In this paper, we consider distributed multi-actuation schemes that combine interbuilding linking elements and interstory actuation devices. Using an advanced static output-feedback H ∞ approach, active and passive vibration control systems are designed for a multi-story two-building structure equipped with a selected set of linked and unlinked actuation schemes. To validate the effectiveness of the obtained controllers, the corresponding frequency responses are investigated and a proper set of numerical simulations is conducted using the full scale North–South El Centro 1940 seismic record as ground acceleration disturbance. The observed results indicate that using combined interstory-interbuilding multi-actuation schemes is an effective means of mitigating the vibrational response of the individual buildings and, simultaneously, reducing the risk of interbuilding pounding. These results also point out that passive control systems with high-performance characteristics can be designed using damping elements.

Design of Vibration Control System for Liquid Tank Transfer with an Overhead Crane

Design of Vibration Control System for Liquid Tank Transfer with an Overhead Crane

アクティブ／セミアクティブハイブリッド制御を用いた振動制御系設計：配置問題の検討

アクティブ／セミアクティブハイブリッド制御を用いた振動制御系設計：配置問題の検討

Control system design of mechanical systems with time varying mechanical and control parameters

A new control framework of motion and/or vibration control system design for mechanical systems with a time varying mechanical and control parameters is studied. As examples of such time varying mechanical and control parameters, we can assume a variable damping or stiffness parameter of semi-active control devices and a time varying weighting function in a generalized plant respectively. The mechanical system in the present study is assumed to have also an actuator for active motion and/or vibration control. The active control law to drive the actuator is obtained by a gain-scheduling controller based on linear matrix inequalities (LMIs) so that the closed-loop system is stable for all assumed values of the time varying mechanical and control parameters in the generalized plant. We use the adjustability of the time varying mechanical and control parameters in the closed-loop system to realize given control specifications. As the control law of the time varying parameters in the closed-loop system, a multi-layered feedforward artificial neural network (ANN) is designed as a dynamic map from available signals in the control system to time varying mechanical and control parameters. Design parameters of the ANN are optimized with a genetic algorithm (GA). With a design example of an active positioning and vibration control of a mechanical system with variable damping coefficient, the proposed design approach is shown to be capable of achieving highly sophisticated control specifications that are hard to be satisfied by conventional control methods.

DYNAMIC STABILITY ANALYSIS AND VIBRATION CONTROL OF A ROTATING ELASTIC BEAM CONNECTED WITH AN END MASS

In this paper, dynamic stability analysis and vibration control for a rotating elastic beam connected with an end mass driven by a direct current (DC) motor is considered. A complete strategy including mathematical modeling, dynamic analysis, vibration controller design and simulation for linear and nonlinear systems are presented. Once the rotating flexible physical system has been described by a set of governing partial differential equations, they are manipulated to achieve an appropriate mathematical format for vibration control system design and computer simulation, respectively. Hamilton principle, Lagrange's equation, assumed-modes and the fourth-order Runge–Kutta methods are applied in the system modeling derivation, descretization, and numerical analysis. The correctness of the numerical results and the characteristic property between mathematics and dynamics are demonstrated as well. Also, a realizable vibration control scheme is developed which not only can stabilize all the vibration modes but also make this rotating elastic beam system efficient for good transient response.

Semi-analytical solutions for optimal distributions of sensors and actuators in smart structure vibration control

In this paper, the optimal design of vibration control system for smart structures has been investigated semi-analytically via the optimization of geometric parameters like the placements and sizes of piezoelectric sensors and actuators (S/As) bonded on the structures. The criterion based on the maximization of energy dissipation was adopted for the optimization of the control system. Based on the sensing and actuating equations, the total energy stored in the system which is used as the objective function was analytically derived with design variables explicitly presented. Two cases of single and combined vibration modes were addressed for a simply supported beam and a simply supported cylindrical shell. For single vibration mode, the optimal distributions of the piezoelectric S/As could be obtained analytically. However, the Sequential Quadratic Programming (SQP) method has to be employed to solve those which violated the prescribed constraints and to solve the case of combined vibration modes. The results of three examples, which include a simply supported beam, a simply supported cylindrical shell and a simply supported plate, showed good agreement with those obtained by the Genetic Algorithm (GA) method. Moreover, in comparison with the GA method, the proposed method is more effective in obtaining better optimization results and is much more efficient in terms of computation time.

Vibration Damping and Isolation Systems Using Direct Inertia Force Control

Recently, active vibration control devices are widely used in many industrial fields. These are categorized into the following two types with their mechanisms. (A) Vibration is controlled by actuators whose one ends are connected to the controlled object and the other ends are connected to “the fixed floor or reaction walls”. (B) Vibration is controlled by actuators whose one ends are connected to the controlled object and the other ends are connected to “the movable mass”. Typical devices of (A) are active vibration isolation devices. The advantage of type (A) is excellent vibration control performance. However, it is difficult to downsize the devices, because the actuator has to support the controlled object. Meanwhile, typical devices of (B) are active mass dampers (AMD). In type (B), since the actuator doesn't need to support the controlled object, it is possible to realize compact systems. However, the control system design of type (B) tends to be complicated, especially for multi-axis plants. In this paper, we propose a new vibration control system design concept called “Direct Inertia Force Control (DIFC)”. By using the DIFC, we can achieve the advantage of the type (A) and (B) simultaneously. Also the DIFC is able to cover the disadvantage of (A) and (B) cited above. Furthermore, the effectiveness of the DIFC is verified by using a newly designed one-degree of freedom active vibration control device, in experiment.

Operator-based non-linear vibration control system design of a flexible arm with piezoelectric actuator

Most real plants must deal with some non-linear characteristics. For the non-linear plants, design of non-linear control system using operator-based robust right coprime factorisation is considered. The considered non-linear control system applications show the desired results. In this paper, operator-based non-linear vibration control of a flexible arm experimental system with uncertainties using robust right coprime factorisation is considered. In general, the vibrations by the characteristic vibration mode include from one to infinite order vibration modes and appear on the arm vibration. It is difficult to consider all vibration modes. Consequently, based on the concept of Lipschitz operators and robust right coprime factorisation condition, robust stability of the closed-loop system with unconsidered vibration modes as uncertainties is guaranteed, and desired vibration control performance actuated by piezoelectric element is ensured. Finally, simulation and experimental results are presented to support the effectiveness of the proposed design.

Modeling Method for Flexible Multibody Systems with Arbitrary Boundary Conditions by Using Extended Reduced-Order Physical Model (2nd Report, Motion and Vibration Control of a Two-link Flexible Robot Arm)

This paper deals with the effectiveness of an Extended Reduced-Order Physical Model (Extended Model) with arbitrary boundary condition for motion and vibration control system design. The Extended Model is proposed to apply to the simultaneous motion and vibration control of elastic structures. The Extended Model consists of some rigid bodies which are called as rigid body elements and stiffness elements. To design rigid body elements, four dynamical conditions are used (1) Total mass and Total moments of inertia, (2) Position of center of gravity, (3) Modal mass and Orthogonality, (4) Modal momentum and Modal angular momentum. The (1) - (4) values of a modeling object are needed to identify masses and moments of inertia of rigid body elements. In the case of that an elastic body has general boundary conditions, the Modal momentum and the Modal angular momentum are not zero and needed to be identified by any means. However, it is not always easy to identify these values. Therefore, a novel formulation to identify mass and inertia matrices is presented that utilizes dynamical conditions for the original object. subjected to free boundary conditions. The presented formulation is applied to the modeling of the two-link flexible robot arm. Each flexible link is modeled by using the proposed modeling method. The two-link flexible robot arm is built by combining two independently identified link models. The effectiveness of “an Extended Model with an arbitrary boundary condition” is shown through the simulation and experimental control results.

Integrated optimal design of vibration control system for smart beams using genetic algorithms

In this paper, the parameters of vibration control system of smart beams, including the placement and size of piezoelectric sensors and actuators (S/As) bonded on smart beams and the feedback control gains of the control system, have been simultaneously optimized for vibration suppression of beam structures. Since the sizes of the S/As are selected from a prescribed patch pool provided by the manufactures, the size design variable is then discrete, but the locations and feedback gains are continuous. Thus, the resulting optimization problem has discrete-continuous design variables which is difficult for the conventional optimization methods to solve. An integer-real-encoded genetic algorithm has thus been developed to search for the optimal placement and size of the piezoelectric patches as well as the optimal feedback control gains. The criterion based on the maximization of energy dissipation was adopted for the optimization of the control system. The optimal distributions of the piezoelectric patches based on specific controlled vibration modes have also been addressed. The results showed that the control effect could be significantly enhanced with appropriate distribution of piezoelectric patches and selection of feedback control gains, and meaningful observations have been obtained for practical design.

ROBUST CONTROL IN BENDING AND TORSIONAL VIBRATIONS OF A FLEXIBLE ROBOT ARM WITH UNCERTAINTY IN PAYLOAD

In this paper, a vibration control system design for a flexible arm that possesses bending and torsional modes is investigated. First, an experimental flexible arm is made with an auxiliary mass connected to the other end via an extension bar so that the center of the stiffness of the arm may not exist in the direction of motion of the auxiliary mass. The auxiliary mass denotes payload. A three-degrees-of-freedom (3DOF) reduced order model is identified according to Seto's procedure. Based on the model obtained, a robust control design procedure utilizing H-infinity control theory is applied. Control experiments are carried out to verify the effectiveness of the presented design procedure.

719 フレキシブルアームの曲げ・ねじれ連成振動のロバスト制御

In this paper, the vibration control system design for a flexible arm that possesses bending-torsional modes is dealt with. First, an experimental flexible arm is made, and an auxiliary mass connected to the other end via an extension bar so that the center of the stiffness of the arm may not exist on the direction of motion of the auxiliary mass. The auxiliary mass denotes payload. Three degree-of-freedom (DOF) reduced order model is identified according to Seto's procedure. Based on the obtained model, robust control design procedure utilizing H-infinity control theory is applied. Computer simulations are carried out and it is clarified that the obtained controller achieved a good performance.

A Multivariable Control System Design which Considers Plural Control Purposes Using Partial Model Matching on Frequency Domain and Its Experimental Evaluation by Pilot-Scale Career in the Warehouse.

Recently, authors have proposed a multivariable linear controller design method based on partial model matching on frequency domain. The practical effectiveness of the method was also confirmed through several experiments using complex mechanical experimental equipment. The application was set limit to the so-called regulator problem including a design of vibration control system. However, there exist many complicated mechanical control systems such that we have to solve regulator problem and tracking control problem simultaneously. This paper is concerned with a design technique of multivariable linear controller on frequency domain, which attains regulator control purpose and tracking control purpose at the same time. The effectiveness of the proposed method is confirmed through an experiment of vibration suppression control and positioning control of pilot scale career in the warehouse with a flexible vibratory pendulum system.

VIBRATION CONTROL OF SHEAR DEFORMABLE LAMINATED PLATES—MODELING IMPLICATIONS

A modal control approach is applied to control the vibration of homogeneous and laminated plates. The controller is designed using the linear optimal control theory. The performance of the controller designed according to a structural model of the plant based on the classical plate theory is evaluated and compared with that derived in the context of a higher order plate theory. It is found that the use of the classical plate model in the design of vibration control systems could lead to erroneous conclusions concerning the performance of the actual controlled system. The strong influence played by transverse shear deformation and lamination on the controlled system is clearly demonstrated and pertinent conclusions are outlined.

Vibration and actuation characteristics of composite structures with a bonded piezo-ceramic actuator

For the design of vibration control systems of composite structures using piezo-ceramic actuators, it is necessary to obtain an accurate system model. Especially, the information related to natural modes, damping ratios and modal actuation forces appears in the governing state space equations. A refined finite element analysis based on the layerwise displacement plate theory has been performed to obtain the system parameters of composite plates with piezoelectric actuators. In this study, the present finite element method has the capability to take account of the stepped effect due to partly bonded piezo-ceramics. Also modal testing techniques have been applied to identify the system parameters experimentally. Through the comparison of numerical results with experimental data, the validity of the numerical procedures has been proved.

Effect of Cure Systems and Reinforcing Fillers on Dynamic Mechanical Properties of Chlorobutyl Elastomers for Potential Vibration-Control Applications

Abstract The effects of four different types of cure systems upon the physical and viscoelastic properties of chlorobutyl elastomers have been investigated. Five different types of carbon black fillers have also been evaluated. Effects of carbon black loading were also studied. The basic conclusions that may be drawn from the experimental determination of the viscoelastic properties of these elastomers and the subsequent use of these to evaluate their potential in various vibration-control applications are as follows: (1) Both the red lead-thiourea cure system, and the resin-cure system give vulcanizates with very similar physical and dynamic mechanical properties. Use of a resin cure is preferable to a red lead-thiourea cure due to the much shorter cure time and lower cure temperature. (2) Chlorobutyl elastomers possess suitable viscoelastic properties for vibration-control applications, due to the diffuse nature of the glass-rubber transition in this class of polymer. Use of other types of fillers, such as silane-treated mica, may be useful in further broadening the temperature-frequency damping range of these materials by introducing additional damping mechanisms. (3) Increased loading of a moderately reinforcing carbon black improves the transmissibility and extensional damping characteristics of CIIRs. An intermediate loading of approximately 35 phr appears to work best for the constrained-layer configuration considered here. (4) An experimental determination of the temperature and frequency dependence of the viscoelastic properties of polymeric materials, coupled with the type of modeling described here, provides a convenient means of assessing the relative merits of various types of polymeric materials in the design of vibration-control systems.