Simulation Of Vibration Control Research Articles

Exhaustive 시험 기법을 이용한 헬리콥터 능동 기체 진동 제어 시뮬레이션

능동 진동 제어 시스템(Active vibration control system, AVCS)을 이용하여 헬리콥터 기체의 능동 진동 제어 시 우수한 진동 제어 성능을 얻기 위하여서는 진동 상쇄 하중 발생기의 개수, 위치 및 하중 방향의 조합의 최적화가 중요하다. 따라서 고려 가능한 모든 하중 발생기의 조합에 대하여 헬리콥터 기체에 대한 AVCS의 진동 제어 성능을 조사하기 위해 Exhaustive 시험 기법을 적용한 AVCS 프레임워크를 구축하였다. 로터 진동 하중 해석, 기체 진동 응답 해석 및 AVCS 시뮬레이션 연구를 수행하기 위해 DYMORE II, MSC.NASTRAN 및 MATLAB Simulink 등 다양한 프로그램을 사용하였다. 이를 이용하여 비행 속도 158 knots의 UH-60A 헬리콥터에 대한 AVCS 적용을 위한 CRFG 조합을 최적화하였다. 최적의 CRFG 조합이 적용된 AVCS를 통해 UH-60A 헬리콥터의 4P 기체 진동 응답을 능동 제어한 결과, 기체의 주요 위치에서 4P 기체 진동 응답이 19.35~98.07%만큼 감소될 수 있었다.

Vibration Suppression for Flexible Plate with Tunable Magnetically Controlled Joint Stiffness/Damping

Large flexible solar panels have the properties of light weight, low stiffness, and weak damping, which leads to low-frequency and large-amplitude vibrations. The existing vibration control methods of solar panels mainly adopt intelligent piezoelectric structures. However, the disadvantage is that the large stroke drive and control are limited. In the present study, a semi-active vibration control approach is proposed for flexible space solar panels based on magnetically controlled joints. The magnetic stiffness comes from the linear relationship between the joint output torque and rotation angle. The magnetic damping stems from the eddy current damping resulting from the relative motion between the permanent magnet rotor and the stator core of the joint. Firstly, the coupling dynamic modeling of a flexible plate and magnetic joints is established by adopting the Lagrange equation and the assumed mode approach. Secondly, semi-active vibration control simulations of the coupled system are performed. Meanwhile, the influence of the variable joint stiffness on the system frequency-shift effect is studied. Finally, the experimental platform is built, and simultaneously, non-contact permanent magnets and airflow are used to simulate single- and multi- frequency excitations, respectively. The experimental results indicate that, in the range of 0.06–0.343 Hz, magnetic damping is the leading factor with magnetic stiffness being the auxiliary. Additionally, it is also experimentally verified that the dual joint actuation has good synchronization. This study provides a new solution for the low-frequency vibration control of large flexible space structures.

Optimization of the location of piezoelectric actuator and sensor in active vibration control using Multi-Verse Optimizer algorithm

In the process of using piezoelectric actuators and sensors to actively control the vibration of flexible structures, the controllability and spillover effect of the system are often the focus of attention, and the location of piezoelectric actuators and sensors is one of the key factors affecting controllability and spillover effect. In this paper, the residual modes are introduced into the location optimization criteria of actuators and sensors, so that the energy can drive as much as possible the eigenmodes that need to be controlled, and avoid driving the residual eigenmodes. At the same time, a modified Multi-Verse Optimizer (MVO) algorithm is used to optimize the location of piezoelectric actuators and sensors. The important results obtained in this paper are compared with the results obtained by the finite element simulation software to verify the accuracy of the relevant derivation results, and the optimization simulation of the position of piezoelectric actuator and the simulation of vibration control are carried out. The simulation results showed that, the MVO algorithm is very suitable for solving the optimization problems that these criteria are non-convex and difficult to derive, and the resulting optimized layout can effectively suppress vibration.

Multi-agent cooperative structural vibration control of three coupled flexible beams based on value decomposition network

Multi-coupled flexible body (MCFB) structure has the characteristics of small damping, close modes and coupled vibration, and the structural vibration is difficult to freely attenuate, which will lead to rapid fatigue failure of the structure. In order to suppress the vibration of the MCFB system quickly, a system identification scheme and a multi-agent reinforcement learning (MARL) scheme are proposed to obtain the cooperative controller. The mathematical model of the three-coupled flexible beam (TCFB) system is identified by wavelet analysis method, particle swarm optimization (PSO) and sinusoidal excitation response method. Based on value decomposition network (VDN) and deterministic policy gradient (DPG), a cooperative MARL framework is constructed to obtain the controller (VDN-DPG controller). The cooperative VDN-DPG controller is applied to the vibration control simulation and experiments of the TCFB system, and compared with proportional–derivative (PD) control without cooperation. The results show that the performance of the VDN-DPG controller is better than that of the PD controller, which verifies the effectiveness of the multi-agent cooperative control scheme based on VDN-DPG.

Low-frequency vibration control of two flexible appendages using a joint with actively tunable stiffness

Low-frequency and large-amplitude vibration of flexible appendages in space can be induced when a spacecraft performs attitude maneuvers and thermal alternations during orbit operation. In this paper, a novel joint mechanism combined with a semi-active method for variable stiffness control is proposed to suppress the low-frequency vibrations of flexible jointed appendages. The variable stiffness of the joint is derived from the linear relationship between its output torque and rotation angle when direct current (DC) power is applied to the coils. Based on the Lagrange equation and the assumed mode method, the coupling dynamic relationships of the active joint and two flexible appendages are established, and semi-active vibration control simulations are performed. A ground experimental platform is built to simulate the microgravity environment in space. The frequency shift effect of rigid body motion and elastic vibration under impact disturbance are investigated. In addition, the effect of variable stiffness control on the elastic deformation of flexible appendages is studied. The simulation and experimental results indicated that the proposed method can control both the rigid body motion of the system and the elastic vibration of the appendages. It has been found that the major frequency bandwidth of the interference signal is within 0.3–1.0 Hz with a substantial vibration attenuation of 1.82–16.62 dB for the joint and 4.86–11.48 dB for the flexible appendages.

An excellent harmonic feedforward-sliding mode output feedback hybrid algorithm for helicopter active vibration control

Higher harmonic control algorithms in frequency domain are generally used for active vibration control of helicopter fuselage. However, these algorithms are inefficient to control transient vibration caused by rapid changing of helicopter flight conditions. Time domain feedback algorithms are efficient to control the transient vibration. In this paper, an excellent harmonic feedforward-sliding mode output feedback hybrid algorithm by combining frequency and time domain algorithms is presented to improve the effect and performance of active vibration control of helicopter fuselage, meanwhile to avoid the requirement of full state information of control system due to using the time domain algorithms. The convergence criterions of the harmonic feedforward algorithm and the hybrid algorithm are theoretically derived, respectively. The convergence speed of the hybrid algorithm is theoretically proved to be faster than that of the harmonic feedforward algorithm. Active vibration control simulation and experiment on a dynamically similar and geometrically scaled frame structure of a helicopter fuselage verify the proposed hybrid algorithm with excellent control effect and performance.

Stability Improvement of Model-Free Control Based on a Virtual Structure Against the Resonance of a Proof-Mass Actuator

PurposeThis study improves the robustness of the model-free controller based on a virtual structure. Additionally, the adverse interference between the proof-mass actuator resonance and a controlled object is investigated as it is not clarified in the previous studies.Methods and ResultsA virtual structure modeled as a SDOF system was inserted between the actuator and the actual controlled object. This achieved the indirect damping of the actual controlled object and model-free control. Vibration control simulations were conducted for various finite element models with a model-free {H}_{infty } controller based on a virtual structure. The results demonstrate that the actuator resonance adversely affects the stability of the control system when the controlled object has a mode whose natural frequency is too close to that of the actuator. Therefore, a notch filter was applied to the model-free {H}_{infty } controller design approach to suppress the resonance without affecting the damping performance. The improved controller with notch filter is more robust to the resonance of the actuator than the previous one.ConclusionsThe resonance of the proof-mass actuator adversely affects the stability of the control system composed of the previous model-free {H}_{infty } controller when the low-order vibration mode of the actual controlled object is too close to the natural frequency of the actuator. Introducing a notch filter into the model-free approach based on a virtual structure effectively reduces the negative impact due to the resonance of the actuator and improves the robustness of the control system.

Model-free Vibration Control of Arbitrary Structures via Multiple Actuators

In general, active vibration control is expected to have a high damping effect, but it is designed using the model of the target structure. Therefore, the designed control system may not achieve the desired damping performance due to modeling errors of the target structure or property fluctuations caused by aging. Since the control system is designed for each target structure, it cannot be used for other target structures. In addition, since the modes that can be damped by a single actuator depend on its placement, there may be some modes that cannot be damped by a single actuator if there are restrictions on its location. In this study, we designed a control system without using a model of the target structure, proposed a method to control vibration of arbitrary structures, and applied this method to multiple actuators. First, a model was created by introducing a virtual structure that represents an arbitrary target structure between the actuator and the target structure. A control system based on the homogeneous exponential stabilization control was designed for this model. Using this controller, vibration control simulations were performed on a finite element model of a nominal cantilever beam. Considering the difference in the vibration control effect for the modes depending on the arrangement of the actuators, the arrangement of multiple actuators was determined. Multiple actuators were applied to the determined configurations, and vibration control simulations were performed for the nominal structure and the structure with characteristic variations to demonstrate the effectiveness of the system.

Research on Optimal Placement of Actuators of High-Rise Buildings Considering the Influence of Seismic Excitation on Structural Modes

Presently, most of the common placement methods of actuators are based on the structural response and system energy to select the optimal locations. In these methods, the contribution of controllability and the energy of seismic excitations to each mode of the structure are not considered, and a large number of cases need to be calculated. To solve this problem, the Clough–Penzien spectral model is combined with the Luenberger observable normal form of the system to calculate the energy of each state. The modal disturbance degree, considering modal energy and controllability, is defined by using the controllability gramian matrix and PBH system controllability index, and the modes are divided into the main disturbance modes (MDMs) and the secondary disturbance modes (SDMs). A novel optimal placement method of actuators based on modal controllability degree is proposed, which uses MDMs as the main control modes. The optimal placement of actuators and the vibration control simulation of a 20-story building model are carried out. The results show that the vibration reduction effect of the proposed placement method is significantly better than that of the method of uniformly distributed actuators (Uniform method) and the classical placement method of actuators based on the system controllability gramian matrix (Classical method).

Active Vibration Control of Helicopter Fuselage with Large Dynamic Modeling Errors

Active vibration control is an effective method for vibration control of a helicopter fuselage. However, when there are large dynamic modeling errors of a control system, the effectiveness of active vibration control may decrease, or even the control may diverge by using the existing harmonic control algorithms. Large modeling errors will result in inaccurate frequency response functions in the control system. In this paper, a new frequency response function updating-harmonic identification algorithm and its convergence condition have been proposed for effective active vibration control of a helicopter fuselage with large modeling errors through identifying the frequency response function of the control system in real time. In addition, to improve the accuracy of identifying frequency response function and further improve the effect of active vibration control, a dynamic harmonic control weight matrix algorithm is also proposed in this paper. The active vibration control simulations and experimental validation on a dynamically similar and geometrically scaled structure of a helicopter fuselage verify that the proposed algorithm in this paper can achieve faster speed of convergence and better effect of vibration control when there are large dynamic modeling errors over the existing harmonic control algorithms.

Parameter tuning technique for a model-free vibration control system based on a virtual controlled object

A parameter tuning technique without manual trial-and-error procedures is proposed for a controller in a model-free vibration control system based on a virtual controlled object (VCO), which is defined as a single-degree-of-freedom (SDOF) system. The model-free control system is constructed by inserting a VCO between the actuator and the actual controlled object. A reference controlled object (RCO), which is also expressed as an SDOF system, is defined for the configured model-free control system. Then the loss function, which is calculated using the RCO vibration control simulation results, is used to evaluate the vibration suppression performance. The simultaneous perturbation stochastic approximation (SPSA) adjusts the controller tuning parameters to minimize the loss function. The SPSA- and RCO-based tuning procedures automatically tune the model-free controller without manual trial-and-error procedures. Simulations and experiments demonstrate that a model-free linear quadratic regulator designed by the proposed approach provides sufficient vibration reduction.

Active Airframe Vibration Control Simulations of Lift-offset Compound Helicopters in High-Speed Flights

This paper studies the simulations of active airframe vibration controls for the Sikorsky X2 helicopter with a lift-offset coaxial rotor. The 4P hub vibratory loads of the X2TD rotor are obtained from the previous work using a rotorcraft comprehensive analysis code, CAMRAD II. The finite element analysis software, MSC.NASTRAN, is used to model the structural dynamics of the X2TD airframe and to analyze the 4P vibration responses of the airframe. A simulation study using Active Vibration Control System(AVCS) with Fx-LMS algorithm to reduce the airframe vibrations is conducted. The present AVCS is modeled using MATLAB Simulink. When AVCS is applied to the X2TD airframe at 250 knots, the 4P longitudinal and vertical vibration responses at the specified airframe positions, such as the pilot seat, co-pilot seat, engine deck, and prop gearbox, are reduced by 30.65 ~ 94.12 %.

Effective finite element model in-loop system of laminated cylindrical structure for multiple inputs and multiple outputs active vibration control

Active vibration control of large laminated cylindrical structures, for example, the cabin of space, air, surficial or subaqueous vehicles, usually requires multiple inputs and multiple outputs to the system, since there are usually multiple vibration sources and each source contains multiple frequency components. The performance of multiple inputs and multiple outputs control system will be dramatically affected by the complex dynamic behavior of the laminated cylindrical structure, thus an effective model is in great request in analyzing and designing the control system. However, there is seldom distributed parametric model, typically, finite element model, applying to the active vibration control system, because of its computational complexity. In this work, we propose an effective finite element model in-loop system of laminated cylindrical structure for multiple inputs and multiple outputs active vibration control simulation. Firstly, an finite element model of laminated thick cylindrical structure with four-node Mindlin degenerated shell element has been constructed. Then, a model reduction procedure has been proposed to obtain in-loop model of the control system. The numerical global modal analysis and harmonic response analysis of the cylindrical structure have been conducted to verify the correctness of the model. Afterward, a multiple inputs and multiple outputs adaptive algorithm which is able to coup with multiple frequencies and multiple sources vibration has been applied to the finite element model in-loop system. Finally, four numerical case studies have been conducted, in which the vibration sources contain multiple frequency components and artificial colored noises. The result shows that the vibration of the multiple control points can be dramatically suppressed simultaneously, which demonstrates the effectiveness of the algorithm and finite element model in-loop system.

A Time-Domain Active Vibration Control Algorithm for Helicopter Based on a Prior Error Channel Identification Strategy

During the flight tests of Z-11 helicopter, the previous method for active vibration control of helicopter suffered from the problems of slow convergence speed and big residual vibration. In order to mitigate these problems, a new method was proposed on the basis of the previous one. Here, a new error channel modeling method is used, which is named the prior error channel identification strategy. And the active control process and the error channel identification process are simplified to improve performance of the system. Besides, the complexity of the method is reduced. Active vibration control simulations were performed based on a simplified model of helicopter fuselage. The simulation results show that the proposed method has lower residual vibration, faster convergence speed, and better capacity for resisting disturbance compared with the previous method. Finally, an active control of structure response experiment was conducted on a free-free beam, and good inhibitory effect of the vibration response of the free-free beam was obtained. The results illustrate that the proposed method based on the prior error channel identification strategy is effective.

The active control of macro-fiber composite over harmonic vibration of arc-plate structures

This paper offers an actuating equation for MFC arc-plate structures to obtain MFC’s accurate actuating force and actuating bending moment to are-plate structures and increase MFC control effect on vibration. This paper proposes the P1 type MFC arc-plate actuating equation which considers the recombination action of MFC and controlled structure, and arc-plate curvature influence on MFC, obtaining the MFC actuating force and actuating bending moment for arc-plate structures. The vibration control experiment of MFC arc-plate structures is performed, and the deviation between finite element simulation results adopting this equation and the experimental data is less than 8.5 %. The research shows that the P1 type MFC actuating equation deduced in this paper is correct and fully applicative to the MFC vibration control simulation to arc-plate structures.

Test and Simulation of an Active Vibration Control System for Helicopter Applications

A significant source of vibration in helicopters is the main rotor system, and it is a technical challenge to reduce the vibration in order to ensure the comfort of crew and passengers. Several types of passive devices have been applied to conventional helicopters in order to reduce the vibration. In recent years, helicopter manufacturers have increasingly adopted active vibration control systems (AVCSs) due to their superior performance with lower weight compared with passive devices. AVCSs can also maintain their performance over aircraft configuration and flight condition changes. As part of the development of AVCS software for light civil helicopter (LCH) applications, a test bench is constructed and vibration control tests and simulations are performed in this study. The test bench, which represents the airframe, is excited using a pair of counter rotating force generators (CRFGs) and a multiple input single output (MISO) AVCS that consists of three accelerometer sensors and a pair of CRFGs; a filtered-x least mean square (LMS) algorithm is applied for the vibration reduction. First, the vibration control tests are performed with uniform sensor weights; then, the change in the control performance according to changes in the sensor weight is investigated and compared with the simulation results. It is found that the vibration control performance can be tuned through adjusting the weights of the three sensors, even if only one actuator is used.

Adaptive Fuzzy Vibration Control of Smart Structure with VFIFE Modeling

ABSTRACTThe vibration control of smart structure is considered in this paper. Membrane SAR antenna structure with piezoelectric sensors and actuators is taken as an example. The dynamic model is build up based on vector form intrinsic finite element (VFIFE) method. The four nodes membrane element, sensor element and actuator element for VFIFE are presented. By decentralized control stratagem, the bending and torsional vibrations of the membrane SAR antenna can be decoupled on measurement and driving control. The fuzzy control and adaptive fuzzy control are applied to suppress the bending and torsional vibrations of the membrane SAR structure. In the numerical experiment section, form finding is first carried out, then vibration control simulations are studied. The results demonstrate that adaptive fuzzy control algorithm can suppress the vibrations more effectively than the fuzzy control algorithm.

Modeling and Controller Comparison for Quarter Car Suspension System by Using PID and Type-1 Fuzzy Logic

Ensuring vehicle drive comfort and securing drive safety are the leading topics among the most interested issues for researchers in vehicle dynamics area. In this paper, a method utilizing a linear actuator is proposed for active control of the vehicle vibrations which are caused by road profile, intending to improve drive comfort and safety of road vehicles. The mathematical model belonging to the system that is evaluated as two degrees of freedom quarter car suspension system is derived by using Lagrange Equation of Motion and MATLAB/Simulink software. In addition to modeling technique, dynamic model of proposed system is created in MSC-ADAMS software and it is simulated in both Matlab and Adams programs together. Moreover two different controllers are designed, which are PID and Artificial Neural Network Based Fuzzy Logic (ANNFL) control in order to use in active vibration control simulations. Performances of the designed controllers are examined and the suitability of the designed controllers is studied by comparing their performances in case of using two different road profile functions.

Dynamical modelling and control of space tethers: a review of space tether research

The literature review manuscript focuses mainly on five topics, which are related to the space tether control researches: (1) space tether dynamical modelling; (2) tether deployment and retrieval; (3) trajectory generation and control; (4) tether attitude and motion control; (5) tether vibration control and dynamical simulations. With the basic aim of establishing useful sources of fundamental researches in the literature, and high-lighting the previous control methods developed, this paper attempts to provide a contextualised source of references for the further space tether dynamics and control studies.

Track-position and vibration control simulation for strut of the Stewart platform

Vibrations inherently generated by on-board disturbance sources degrade the performance of the instruments in an on-orbit spacecraft, which have stringent accuracy requirements. The Stewart platform enables both track-positioning and vibration control. The strut of the Stewart platform is designed as a piezoelectric (PZT) element in series with a voice coil motor (VCM) element and a viscoelastic element. The track-positioning system uses a VCM as the main positioning control driver and a PZT as the positioning compensator. The vibration control system uses the characteristics of struts including active and passive control elements to attenuate the vibration. Simulation results indicate that the Stewart platform with the designed struts has good performance in tracking and vibration attenuation with different interference waves.