Smart Materials-Based Structural Vibration Isolation for Minimizing Product Quality Variation Using H∞-Based Optimal Control

Manufacturing ◽  
2002 ◽  
Author(s):  
J. A. Turso ◽  
J. T. Roth
Keyword(s):  
Smart Materials ◽  
Vibration Isolation ◽  
Piezoelectric Actuators ◽  
Structural Vibration ◽  
Band Model ◽  
Manufacturing Equipment ◽  
Patch Type ◽  
Simulation Testing ◽  
Nominal Performance ◽  
Piezoelectric Actuators And Sensors

An H∞-Based optimal vibration isolation system using patch-type piezoelectric actuators and sensors, suitable for application on high-precision manufacturing equipment that is being affected by external disturbances, has been designed. Reductions of the force transmitted through the structure range from approximately 5 to 30 dB in the frequency band of interest. Robust stability, nominal performance and robust performance have all been verified using the structured singular value, μ, and simulation testing for the set of plants within a derived uncertainty set. In addition, the H∞ controller is compared to an LQG-optimal controller designed for the same structure. The LQG controller, while achieving nominal performance comparable to the H∞ controller and being of significantly lower order, was shown to be unstable via μ-analysis and simulation testing. Thus, the LQG design should not be applied to a machine where there is significant in-band model uncertainty. Use of light-weight patch-type piezoelectric actuators and sensors provides a low-cost, easily-installable way of applying this technique to manufacturing equipment requiring isolation from low-frequency disturbances.

Sliding Mode Control of a Gossamer Structure Using Smart Materials

2004 ◽  
Vol 10 (8) ◽  
pp. 1199-1220 ◽  
Author(s):  
Akhilesh K. Jha ◽  
Daniel J. Inman
Keyword(s):  
Smart Materials ◽  
Polyvinylidene Fluoride ◽  
Vibration Suppression ◽  
Sliding Mode ◽  
Fiber Composite ◽  
Piezoelectric Actuators ◽  
System Structure ◽  
Mode Shapes ◽  
Space Applications ◽  
Piezoelectric Actuators And Sensors

Gossamer structures have been a subject of renewed interest for space applications because of their low weights, on-orbit deploying capabilities, and minimal stowage volumes. In this study, vibration suppression of an inflated structure using piezoelectric actuators and sensors has been attempted. These actuators and sensors can be suitably used for gossamer structures since they can conform to curved surfaces and provide distributed actuation and sensing capabilities. Using the natural frequencies and mode shapes of the system (structure, actuators, and sensors), a state-space model is derived. For designing a robust vibration controller, we used a sliding mode technique. The derivations of the sliding model controller and observer are presented in details. Finally, by means of numerical analysis, the method was demonstrated for an inflated torus considering Macro-Fiber Composite (MFC™) as actuators and Polyvinylidene Fluoride (PVDF) as sensors. The simulation studies show that the piezoelectric actuators and sensors are suitable for vibration suppression of an inflatable torus. The robustness properties of the controller and observer against the parameter uncertainty and disturbances are also studied.

Modeling and Testing of an Autonomous Swimming Vehicle Powered via Smart Materials

2001 ◽  
Author(s):  
Michael G. Borgen ◽  
Gregory N. Washington ◽  
Gary Kinzel
Keyword(s):  
Smart Materials ◽  
Digital Control ◽  
Piezoelectric Actuators ◽  
Euler Method ◽  
Vehicle Design ◽  
Curved Beam ◽  
Experimental Performance ◽  
Flexible Fin ◽  
Optimization Routine ◽  
Beam Bending

Abstract This work details the design of a miniature swimming vehicle that propels itself through oscillations of a flexible fin mounted in the stern. The fin is driven through a mechanism that is actuated by two curved-beam bending piezoelectric actuators. An optimization routine is used to design the mechanism for rigid body guidance. The actuators are modeled statically using the Bernoulli-Euler method. Hamilton’s principle is applied to the actuators and, by employing modal analysis, a dynamic actuator model is developed and compared to experimental data. The physical evolution of the swimming vehicle is discussed, and a prototype for an onboard digital control circuit is evaluated. The latest vehicle design, which incorporates onboard digital control, is presented in terms of its design and experimental performance characteristics. The current swimming vehicle prototype achieves fish-like maneuvering and an approximate velocity of 0.25 m/s.

scholarly journals Research on dynamic characteristics of plate under pedestrian excitation based on Newmark-β

2018 ◽  
Vol 37 (4) ◽  
pp. 682-699
Author(s):  
Xinfang Ge ◽  
Weirong Wang ◽  
Wei Yuan
Keyword(s):  
Rectangular Plate ◽  
Dynamic Characteristics ◽  
Vibration Isolation ◽  
Great Influence ◽  
Interaction Model ◽  
Vertical Direction ◽  
Structural Vibration ◽  
Normal Walking ◽  
Plate Structure ◽  
Pedestrian Excitation

Development of micro and ultra-precision machining, precision instruments and equipment, precision assembly and testing has put forward more and more high requirements to vibration isolation on environmental elements, especially the pedestrian excitation generated by workers' normal walking. Therefore, it is very important to study the pedestrian excitation's influence on vibration characteristics of precision instruments and equipment. In this study, dynamic model including mathematical model of pedestrian excitation, interaction model between pedestrian and rectangular plate structure, the human–plate coupled dynamic equation in vertical direction of pedestrian–plate structure was established. And then we use the Newmark-β method to solve the time-domain step-by-step integration of the first four order modes' dynamic equations and study the influence of the linear notion trajectory along the central axis direction on the dynamic characteristics of the rectangular plate. By simulation, we discussed plate structure response under different conditions, including plate structure displacement and acceleration response under the single person excitation with different velocities, under normal walking velocity with different number of pedestrians and under this case of different distance between two pedestrians. The results show that the structural vibration induced by pedestrian excitation has great influence on dynamic characteristics of plate.

Hybrid Control of Rotating Beams Using Pattern Search Based Optimization Technique

2018 ◽  
Author(s):  
Rajiv Kumar Vashisht ◽  
Qingjin Peng
Keyword(s):  
Smart Materials ◽  
Optimization Technique ◽  
Flexible Structures ◽  
Pattern Search ◽  
Feedback Controller ◽  
Structural Vibration ◽  
Flexible Beam ◽  
Constrained Layer Damping ◽  
Rotating Beams ◽  
Passive Constrained Layer Damping

Rotating beams are quite common in rotating machinery e.g. fans of compressors in an airplane. This paper presents the experimental, hybrid, structural vibration control of flexible structures to enhance the vibration behavior of rotating beams. Smart materials have been used as sensors as well as actuators. Passive constrained layer damping (PCLD) treatment is combined with stressed layer damping technique to enhance the damping characteristics of the flexible beam. To further enhance the damping parameters, a closed form robust feedback controller is applied to reduce the broadband structural vibrations of the rotating beam. The feed forward controller is designed by combing with the feedback controller using a pattern search based optimization technique. The hybrid controller enhances the performance of the closed loop system. Experiments have been conducted to validate the effectiveness of the presented technique.

Comparison of Active and Hybrid Vibration Confinement With Conventional Active Vibration Control

1999 ◽  
Author(s):  
Lawrence R. Corr ◽  
William W. Clark
Keyword(s):  
Vibration Control ◽  
Control Method ◽  
Numerical Study ◽  
Active Vibration Control ◽  
Piezoelectric Actuators ◽  
Control Technique ◽  
Flexible Beam ◽  
Velocity Feedback ◽  
Active Vibration ◽  
Piezoelectric Actuators And Sensors

Abstract This paper presents a numerical study in which active and hybrid vibration confinement is compared with a conventional active vibration control method. Vibration confinement is a vibration control technique that is based on reshaping structural modes to produce “quiet areas” in a structure as opposed to adding damping as in conventional active or passive methods. In this paper, active and hybrid confinement is achieved in a flexible beam with two pairs of piezoelectric actuators and sensors and with two vibration absorbers. For comparison purposes, active damping is achieved also with two pairs of piezoelectric actuators and sensors using direct velocity feedback. The results show that both approaches are effective in controlling vibrations in the targeted area of the beam, with direct velocity feedback being slightly more cost effective in terms of required power. When combined with passive confinement, however, each method is improved with a significant reduction in required power.

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