Homogeneous Material Constructed Acoustic Cloak Based on Coordinate Transformation

2012 ◽  
Vol 134 (5) ◽  
Author(s):  
Tinghua Li ◽  
Ming Huang ◽  
Jingjing Yang ◽  
Yaozhong Lan ◽  
Jing Sun
Keyword(s):  
Coordinate Transformation ◽  
Mass Density ◽  
Three Dimensional ◽  
Transformation Method ◽  
Homogeneous Material ◽  
Spatial Transformation ◽  
Practical Realization ◽  
Full Wave ◽  
Coordinate Transformation Method ◽  
Important Progress

The two-dimensional and three-dimensional acoustic cloaks composed of homogeneous and nonsingular materials are designed by choosing appropriate spatial transformation. The mass density tensor and bulk modulus of the acoustic cloaks with diamond shape are derived, and extended to an acoustic carpet cloak. Performance of the acoustic cloaks is confirmed by full-wave simulation. The work represents an important progress towards the practical realization of the metamaterial-assisted acoustic cloak and expands the application of the coordinate transformation method.

DESIGN OF THE N-SIDED REGULAR POLYGONAL TRANSPARENT DEVICE USING METAMATERIALS

2012 ◽  
Vol 26 (30) ◽  
pp. 1250162 ◽  
Author(s):  
JING-JING YANG ◽  
MING HUANG ◽  
SHU-JUAN MU ◽  
SAI CHENG ◽  
MENG WANG ◽  
...  
Keyword(s):  
Finite Element ◽  
Coordinate Transformation ◽  
Transformation Method ◽  
Cylindrical Wave ◽  
Comsol Multiphysics ◽  
Material Parameters ◽  
Full Wave ◽  
Field Distributions ◽  
Coordinate Transformation Method ◽  
Incident Waves

Based on the coordinate transformation method, we derived the material parameters for arbitrary N-sided regular polygonal transparent device, which is an important device for antenna protection. The electric field distributions of the device under TE wave and cylindrical wave irradiation are simulated using the finite element solver COMSOL Multiphysics. It shows that although the incident waves are distorted in the transformation region, they return to the original wavefronts when passing through the transformation region. The results of full-wave simulations validate the material parameters for the N-sided regular polygonal transparent device we derived.

Acoustic Metamaterial Design Method Based on Green Coordinate Transformation

2020 ◽  
Vol 976 ◽  
pp. 15-24
Author(s):  
Xin Xie ◽  
Xiao Ming Wang ◽  
Yu Lin Mei
Keyword(s):  
Coordinate Transformation ◽  
Design Method ◽  
Three Dimensional ◽  
Transformation Method ◽  
Propagation Path ◽  
Acoustic Metamaterials ◽  
Acoustic Wave Propagation ◽  
Acoustic Metamaterial ◽  
Coordinate Transformation Method ◽  
Transformation Acoustics

Acoustic metamaterials have great application prospects in eliminating vibration and noise, but they are difficult to manufacture due to their anisotropy. This paper utilizes the Green coordinate transformation method to design acoustic metamaterials by combining with the transformation acoustics theory. Because the Green coordinate transformation is the pseudo-conformal mapping in three-dimensional coordinates, the anisotropy of designed metamaterials can be weakened. And also, the genetic algorithm is employed to optimize the anisotropy of metamaterials and reduce the designed metamaterial parameter difference further. Finally, the membrane-imbedded-type metamaterial is applied to realize the design and to illustrate the effectiveness of the proposed method by manipulating the acoustic wave propagation path.

A Study of Tracking System Using Multiple Emitter Towers

2013 ◽  
Vol 694-697 ◽  
pp. 927-935 ◽  
Author(s):  
Yi Sun ◽  
Tao Ma ◽  
Chia Yung Han ◽  
Joseph Ross ◽  
William Wee
Keyword(s):  
Coordinate Transformation ◽  
Motion Tracking ◽  
Tracking System ◽  
Transformation Method ◽  
Tracking Accuracy ◽  
Working Space ◽  
Frontal Part ◽  
Motion Tracking System ◽  
Coordinate Transformation Method

This paper presents a simple and accurate coordinate transformation method for extending the tracking space of the Intersense IS-900 spatial and motion tracking system using multiple pre-configured emitter towers to form the emitter constellation, but without resorting to the use of a surveyor machine. The proposed approach uses the differences of positional coordinate readings from each emitter tower among a set of commonly viewed spatial points to calculate the parameters needed to define the coordinate transformation. By applying this method, the tracking accuracy using the entire emitter constellation can be achieved by less than 0.5 inches error in most of the working space, and as low as 0.2 inches error in the frontal part of the working space.

Study on NURBS Surface Tool Trajectory Planning of 6R Engraving Robot

2013 ◽  
Vol 711 ◽  
pp. 422-425 ◽  
Author(s):  
Yu Hu Zuo
Keyword(s):  
Trajectory Planning ◽  
Coordinate Transformation ◽  
Inverse Kinematics ◽  
End Milling ◽  
Transformation Method ◽  
Nurbs Surface ◽  
Calculation Algorithm ◽  
Tool Trajectory ◽  
Coordinate Transformation Method ◽  
Cutting Point

A NURBS surface tool trajectory planning method of engraving robot is proposed. The calculation algorithm including NURBS surface tool trajectory, cutting point and effective cutting radius of end milling cutter and inverse kinematics transform is discussed in detail using Taylor and coordinate transformation method. It is the foundation to further applied to the engraving robot tool trajectory planning or off-line programming.

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