Nonlinear Adaptive Vibration Absorber for the Control of Plate Vibrations

2001 ◽  
Author(s):  
Osama N. Ashour ◽  
Ali H. Nayfeh
Keyword(s):  
Control Strategy ◽  
Flexible Structures ◽  
Digital Signal ◽  
Nonlinear Effects ◽  
Frequency Measurement ◽  
Control Technique ◽  
Vibration Absorber ◽  
Plate Vibrations ◽  
Near Resonance ◽  
Modeling Software

Abstract A nonlinear adaptive vibration absorber to control the vibrations of flexible structures is investigated. The absorber is based on the saturation phenomenon associated with dynamical systems possessing quadratic nonlinearities and a two-to-one internal resonance. The technique is implemented by coupling a second-order controller with the structure’s response through a sensor and an actuator. Energy is exchanged between the structure and the controller and, near resonance, the structure’s response saturates to a small value. Experimental results are presented for the control of a rectangular plate and a cantilever beam using piezoelectric ceramics and magnetostrictive alloys as actuators. The control technique is implemented using a digital signal processing board and a modeling software. The control strategy is made adaptive by incorporating an efficient frequency-measurement technique. This is validated by successfully testing the control strategy for a non-conventional problem, where nonlinear effects hinder the application of the nonadaptive controller.

Experimental and Numerical Analysis of a Nonlinear Vibration Absorber for the Control of Plate Vibrations

2003 ◽  
Vol 9 (1-2) ◽  
pp. 209-234 ◽  
Author(s):  
Osama N. Ashour ◽  
Ali H. Nayfeh
Keyword(s):  
Finite Element ◽  
Experimental Studies ◽  
Digital Signal ◽  
Experimental Results ◽  
Control Technique ◽  
Vibration Absorber ◽  
Element Analysis ◽  
Plate Vibrations ◽  
Near Resonance ◽  
Modeling Software

We investigate a nonlinear active vibration absorber to control the vibrations of plates. The absorber is based on the saturation phenomenon associated with dynamical systems with quadratic nonlinearities and a two-to-one internal resonance. The technique is implemented by coupling a second-order controller with the plate's response through a sensor and an actuator. Energy is exchanged between the primary structure and the controller and, near resonance, the plate's response saturates to a small value. Numerical as well as experimental results are presented for a cantilever rectangular plate. For the numerical studies, finite-element methods as well as modal analysis are implemented. The commercially available software ABAQUS is used in the finite-element analysis together with a user-provided subroutine to model the controller. For the experimental studies, the plate is excited using a dynamic shaker. Strain gages are used as sensors, while piezoelectric ceramic patches are used as actuators. The control technique is implemented using a digital signal processing board and a modeling software. Both numerical and experimental results show that the control strategy is very effective.

Research on cyber-physical system control strategy under false data injection attack perception

2022 ◽  
pp. 014233122110693
Author(s):  
Zhiwen Wang ◽  
Bin Zhang ◽  
Xiangnan Xu ◽  
Usman ◽  
Long Li
Keyword(s):  
Control Strategy ◽  
Physical System ◽  
Sufficient Conditions ◽  
Switched System ◽  
Lyapunov Methods ◽  
Control Technique ◽  
Cyber Physical System ◽  
Time Data ◽  
False Data Injection ◽  
Injection Attacks

This paper investigates the security control problem of the cyber-physical system under false data injection attacks. A model predictive switching control strategy based on attack perception is proposed to compensate for the untrusted sequence of data caused by false data injection attacks. First, the binary attack detector is applied whether the system has suffered the attack. If the attack occurs, multistep correction is carried out for the future data according to the previous time data, and the waiting period [Formula: see text] is set. The input and output sequence of the controller is reconstructed, and the system is modeled as a constant time-delay switched system. Subsequently, the Lyapunov methods and average-dwell time are combined to provide sufficient conditions for the asymptotical stability of closed-loop switched system. Finally, the simulation of the networked first-order inverted pendulum model reveals that the control technique can efficiently suppress the influence of the attacks.

Nonlinear Torsional Vibration Absorber for Flexible Structures

2018 ◽  
Vol 86 (2) ◽  
Author(s):  
Xiao-Ye Mao ◽  
Hu Ding ◽  
Li-Qun Chen
Keyword(s):  
High Efficiency ◽  
Rotation Angle ◽  
Flexible Structures ◽  
Nonlinear Energy Sink ◽  
Flexible Structure ◽  
Vibration Absorber ◽  
Special Perturbation ◽  
Energy Sink ◽  
Simulation Parameters ◽  
Nonlinear Energy

A new kind of nonlinear energy sink (NES) is proposed to control the vibration of a flexible structure with simply supported boundaries in the present work. The new kind of absorber is assembled at the end of structures and absorbs energy through the rotation angle at the end of the structure. It is easy to design and attached to the support of flexible structures. The structure and the absorber are coupled just with a nonlinear restoring moment and the damper in the absorber acts on the structure indirectly. In this way, all the linear characters of the flexible structure will not be changed. The system is investigated by a special perturbation method and verified by simulation. Parameters of the absorber are fully discussed to optimize the efficiency of it. For the resonance, the maximum motion is restrained up to 90% by the optimized absorber. For the impulse, the vibration of the structure could attenuate rapidly. In addition to the high efficiency, energy transmits to the absorber uniaxially. For the high efficiency, convenience of installation and the immutability of linear characters, the new kind of rotating absorber provides a very good strategy for the vibration control.

Trajectory control and random vibration control of nonlinear system with dielectric elastomer actuator

2018 ◽  
Vol 29 (11) ◽  
pp. 2424-2436 ◽  
Author(s):  
Yanping Tian ◽  
Yong Wang ◽  
Xiaoling Jin ◽  
Zhilong Huang
Keyword(s):  
Nonlinear System ◽  
Control Strategy ◽  
Primary Structure ◽  
Equilibrium Position ◽  
Random Vibration ◽  
Dielectric Elastomer ◽  
Control Technique ◽  
Dynamic Programming Principle ◽  
Dielectric Elastomer Actuator ◽  
Dielectric Elastomer Actuators

Dielectric elastomer actuators have gained extensive attention in scientific and industrial communities with the rapid development of soft robot technology. There still remain some questions on the control aspect of nonlinear system with dielectric elastomer actuator. The first is whether the soft actuator can successfully drive the primary structure to track an arbitrary prescribed trajectory. The second is how to suppress the random vibration around the equilibrium position when the primary structure is disturbed by external excitation. This article seeks the answers for these two questions. By directly solving the governing equation of motion, an open-loop control technique is designed to track a prescribed trajectory. The effectiveness of the trajectory tracking technique is investigated and the limitation is illustrated by the influence of inertia of the primary structure. Based on the stochastic averaging of energy envelope and stochastic dynamic programming principle, a clipped control strategy is proposed by slightly adjusting the voltage in real time to suppress the random vibration around the equilibrium position. The good effectiveness and high robustness of the clipped control strategy are verified numerically. This work may provide some guidelines for the control aspect of nonlinear systems with dielectric elastomer actuators.

scholarly journals Nonlinear gas oscillations in pipes. Part 1. Theory

1973 ◽  
Vol 59 (1) ◽  
pp. 23-46 ◽  
Author(s):  
J. Jimenez
Keyword(s):  
Boundary Conditions ◽  
Equations Of Motion ◽  
Nonlinear Effects ◽  
Wave Form ◽  
Cube Root ◽  
Acoustic Oscillations ◽  
Open Mouth ◽  
Near Resonance ◽  
Reflexion Coefficient ◽  
Two Parameters

The problem of forced acoustic oscillations in a pipe is studied theoretically. The oscillations are produced by a moving piston in one end of the pipe, while a variety of boundary conditions ranging from a completely closed to a completely open mouth at the other end are considered. All these boundary conditions are modelled by two parameters: a length correction and a reflexion coefficient equivalent to the acoustic impedance.The linear theory predicts large amplitudes near resonance and nonlinear effects become crucially important. By expanding the equations of motion in a series in the Mach number, both the amplitude and wave form of the oscillation are predicted there.In both the open- and closed-end cases the need for shock waves in some range of parameters is found. The amplitude of the oscillation is different for the two cases, however, being proportional to the square root of the piston amplitude in the closed-end case and to the cube root for the open end.

Order-Tuned Vibration Absorbers for Cyclic Rotating Flexible Structures

2005 ◽  
Author(s):  
Brian J. Olson ◽  
Steve W. Shaw ◽  
Christophe Pierre
Keyword(s):  
Equations Of Motion ◽  
Flexible Structures ◽  
Closed Form Solution ◽  
Nonlinear Effects ◽  
Form Solution ◽  
Vibration Absorbers ◽  
Bladed Disk ◽  
Tuned Vibration Absorbers ◽  
Engine Order ◽  
Bladed Disk Assembly

This paper investigates the use of order-tuned absorbers to attenuate vibrations of flexible blades in a bladed disk assembly subjected to engine order excitation. The blades are modeled by a cyclic chain of N oscillators, and a single vibration absorber is fitted to each blade. These absorbers exploit the centrifugal field arising from rotation so that they are tuned to a given order of rotation, rather than to a fixed frequency. A standard change of coordinates based on the cyclic symmetry of the system essentially decouples the governing equations of motion, yielding a closed form solution for the steady-state response of the overall system. These results show that optimal reduction of blade vibrations is achieved by tuning the absorbers to the excitation order n, but that the resulting system is highly sensitive to small perturbations. Intentional detuning (meaning that the absorbers are slightly over- or under-tuned relative to n) can be implemented to improve the robustness of the design. It is shown that by slightly undertuning the absorbers there are no system resonances near the excitation order of interest and that the resulting system is robust to mistuning (i.e., small random uncertainties in the system parameters) of the absorbers and/or blades. These results offer a basic understanding of the dynamics of a bladed disk assembly fitted with order-tuned vibration absorbers, and serve as a first step to the investigation of more realistic models, where, for example, imperfections and nonlinear effects are considered, and multi-DOF and general-path absorbers are employed.

EXPERIMENTAL REALIZATION OF DYNAMIC STAIR CLIMBING AND DESCENDING OF BIPED HUMANOID ROBOT, HUBO

2009 ◽  
Vol 06 (02) ◽  
pp. 205-240 ◽  
Author(s):  
JUNG-YUP KIM ◽  
ILL-WOO PARK ◽  
JUN-HO OH
Keyword(s):  
Control Strategy ◽  
High Performance ◽  
Humanoid Robot ◽  
Stair Climbing ◽  
Control Technique ◽  
Experimental Realization ◽  
Biped Walking ◽  
Switching Control Strategy ◽  
Stair Walking ◽  
And Performance

In this paper, dynamic stair climbing and descending are experimentally realized for a biped humanoid robot, HUBO. Currently, in addition to biped walking on the ground, other types of biped walking such as running, jogging, and stair walking (climbing and descending) have been also studied since the end of 1990. In spite of many years of research works on stair walking, it is still a challengeable topic that requires high performance of control technique. For dynamic stair walking, we designed stair climbing and descending patterns according to a known stair configuration. Next, we defined stair climbing and descending stages for a switching control strategy. In each stage, we designed and adopted several online controllers to maintain the balance. For the simplicity and easy application, the online controllers only use the force and torque signals of the force/torque sensors of the feet. Finally, the effectiveness and performance of the proposed strategy are verified through stair climbing and descending experiments of HUBO.

Two Methods to Broaden the Bandwidth of a Nonlinear Piezoelectric Bimorph Power Harvester

2017 ◽  
Vol 139 (3) ◽  
Author(s):  
Hongping Hu ◽  
Longxiang Dai ◽  
Hao Chen ◽  
Shan Jiang ◽  
Hairen Wang ◽  
...  
Keyword(s):  
Large Deformations ◽  
Initial Conditions ◽  
Flexural Vibration ◽  
Nonlinear Effects ◽  
Voltage Source ◽  
Energy Scavenging ◽  
Piezoelectric Bimorph ◽  
Near Resonance ◽  
Jump Phenomena ◽  
Power Harvester

We propose two methods to broaden the operation bandwidth of a nonlinear pinned–pinned piezoelectric bimorph power harvester. The energy-scavenging structure consists of a properly poled and electroded flexible bimorph with a metallic layer in the middle, and is subjected to flexural vibration. Nonlinear effects at large deformations near resonance are considered by taking the in-plane extension of the bimorph into account. The resulting output powers are multivalued and exhibit jump phenomena. Two methods to broaden the operation bandwidth are proposed: The first method is to extend the operation frequency to the left single-valued region through optimal design. The second method is to excite optimal initial conditions with a voltage source. Larger output powers in the multivalued region of the nonlinear harvester are obtained. Hence, the operation bandwidth is broadened from the left single-valued region to the whole multivalued region.

Periodic Perturbation Method for Controlling Chaos for a Positive Output DC-DC Luo Converter

2017 ◽  
Vol 8 (2) ◽  
pp. 775 ◽  
Author(s):  
P. Balamurugan ◽  
A. Kavitha ◽  
P. Sanjeevikumar ◽  
J.L. Febin Daya ◽  
Tole Sutikno
Keyword(s):  
Control Strategy ◽  
Chaotic Attractor ◽  
Current Mode ◽  
Chaotic Regime ◽  
Periodic Perturbation ◽  
Control Technique ◽  
Controlling Chaos ◽  
Stable Period ◽  
Feedback Method ◽  
A Current

<p>A simple, non-feedback method of controlling chaos is implemented for a DC-DC converter. The weak periodic perturbation (WPP) is the control technique applied to stabilize an unstable orbit in a current-mode controlled Positive Output Luo (POL) DC-DC converter operating in a chaotic regime. With WPP, the operation of the converter is limited to stable period-1 orbit that exists in the original chaotic attractor. The proposed control strategy is implemented using simulations and the results are verified with hardware setup. The experimental results of the converter with WPP control are presented which shows the effectiveness of the control strategy.</p>

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