Active and Passive Vibration Control Using Compact Damping Patches: Assessment of a Reduced Order Model for an Euler Beam

2015 ◽  
Author(s):  
Joseph Plattenburg ◽  
Jason T. Dreyer ◽  
Rajendra Singh
Keyword(s):  
Computational Models ◽  
Parametric Design ◽  
Reduced Order Model ◽  
System Response ◽  
Control Input ◽  
Passive Damping ◽  
Order Model ◽  
Euler Beam ◽  
Reduced Order ◽  
Developing Area

Concurrent placement of compact active and passive damping patches for vibration reduction is a developing area of research. Analytical and computational models to evaluate alternate patch configurations and structural geometries are not widely available. To overcome this void, this paper presents a simplified discrete-system model for vibrations of a beam-like structure. A disturbance input is included in the model, along with a control input from an active patch. Localized structural damping resulting from a passive patch is modeled with an equivalent loss factor. Results from the simplified model are verified using a more detailed analytical formulation, which is based on the Ritz approximation. Verification studies include the effect of a passive damping patch on modal loss factors and broadband attenuation. Finally, a few case studies are proposed which show the efficacy of the reduced-order model for parametric design studies. These studies include determining the effect of localized damping on the control system parameters that are required for attenuation of localized and global motions. The effect of patch locations on system response is also studied. This work has potential applications in industry since compact damping patches are attractive NVH treatments that add minimal weight and complexity.

Control Input Separation Methods for Reduced-Order Model-Based Feedback Flow Control

AIAA Journal ◽  
2008 ◽  
Vol 46 (9) ◽  
pp. 2306-2322 ◽  
Author(s):  
Edgar Caraballo ◽  
Coşku Kasnakoglu ◽  
Andrea Serrani ◽  
Mo Samimy
Keyword(s):  
Flow Control ◽  
Reduced Order Model ◽  
Control Input ◽  
Order Model ◽  
Reduced Order ◽  
Model Based

Validated Reduced Order Models for Simulating Trajectories of Bio-Inspired Artificial Micro-Swimmers

2010 ◽  
Author(s):  
Ahmet Fatih Tabak ◽  
Serhat Yesilyurt
Keyword(s):  
Rigid Body Dynamics ◽  
The Body ◽  
Reduced Order Model ◽  
Control Input ◽  
Body Frame ◽  
Order Model ◽  
Reduced Order ◽  
Resistive Force ◽  
Resistive Force Theory ◽  
Good Agreement

Autonomous micro-swimming robots can be utilized to perform specialized procedures such as in vitro or in vivo medical tasks as well as chemical surveillance or micro manipulation. Maneuverability of the robot is one of the requirements that ensure successful completion of its task. In micro fluidic environments, dynamic trajectories of active micro-swimming robots must be predicted reliably and the response of control inputs must be well-understood. In this work, a reduced-order model, which is based on the resistive force theory, is used to predict the transient, coupled rigid body dynamics and hydrodynamic behavior of bio-inspired artificial micro-swimmers. Conceptual design of the micro-swimmer is biologically inspired: it is composed of a body that carries a payload, control and actuation mechanisms, and a long flagellum either such as an inextensible whip like tail-actuator that deforms and propagates sinusoidal planar waves similar to spermatozoa, or of a rotating rigid helix similar to many bacteria, such as E. Coli. In the reduced-order model of the micro-swimmer, fluid’s resistance to the motion of the body and the tail are computed from resistive force theory, which breaks up the resistance coefficients to local normal and tangential components. Using rotational transformations between a fixed world frame, body frame and the local Frenet-Serret coordinates on the helical tail we obtain the full 6 degrees-of-freedom relationship between the resistive forces and torques and the linear and rotational motions of the swimmer. In the model, only the tail’s frequency (angular velocity for helical tail) is used as a control input in the dynamic equations of the micro-swimming robot. The reduced-order model is validated by means of direct observations of natural micro swimmers presented earlier in the literature and against; results show very good agreement. Three-dimensional, transient CFD simulations of a single degree of freedom swimmer is used to predict resistive force coefficients of a micro-swimmer with a spherical body and flexible tail actuator that uses traveling plane wave deformations for propulsion. Modified coefficients show a very good agreement between the predicted and actual time-dependent swimming speeds, as well as forces and torques along all axes.

Mixed Method of Routh and ISE Criterion Approaches for Reduced-Order Modeling of Continuous-Time Systems

1984 ◽  
Vol 106 (4) ◽  
pp. 353-356 ◽  
Author(s):  
Chyi Hwang
Keyword(s):  
Mixed Method ◽  
Continuous Time ◽  
Reduced Order Model ◽  
System Response ◽  
Order Model ◽  
Reduced Order ◽  
Minimum Mean Squared Error ◽  
Squared Error ◽  
Continuous Time Systems ◽  
Time Systems

A mixed method using the advantages of Routh approximation method and integral-squared-error criterion is proposed for obtaining stable reduced-order models for high-order continuous-time systems. The reduced-order model tends to approximate the transient portion of the system response in the sense of minimum mean-squared-error, while the steady-state portion is matched exactly. Instead of actually evaluating time responses of the system and the reduced-order model, a matrix formula is used to calculate the integral-squared-error from the error transfer function.

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