Optical Waveguide Theory

생체의 모델링과 Simulation

A paradigm shift has emerged over the last decade pointing to an exciting research area dealing with the harnessing of elastic structural instabilities for ‘smart’ purposes in a variety of venues. Among the different types of unstable responses, buckling is a phenomenon that has been known for centuries, and yet it is generally avoided through special design modifications. Increasing interest in the design of smart devices and mechanical systems has identified buckling and postbuckling response as a favorable behavior. The objective of this topical review is to showcase the recent advances in buckling-induced smart applications and to explain why buckling responses have certain advantages and are especially suitable for these particular applications. Interesting prototypes in terms of structural forms and material uses associated with these applications are summarized. Finally, this review identifies potential research avenues and emerging trends for using buckling and other elastic instabilities for future innovations.

https://iopscience.iop.org/article/10.1088/0964-1726/24/6/063001/pdf

Buckling-induced smart applications: recent advances and trends

Nonlinear finite element analysis of solids and structures by M.A. Crisfield

A review of topology optimization for additive manufacturing: Status and challenges

AbstractHand-eye calibration is the basis of machine vision. The calibration method determines the motion accuracy of the manipulator. In the presented method, the point coordinate in camera frame and robot frame are separately obtained. By stacking the formula, the hand-eye transformation matrix can be calculated using the least square method. Otherwise, a tool offset calibration method is presented and some guidance also of conducting the tool offset calibration experiment is given. Finally, the validity of the proposed method is demonstrated by and experimental studies.KeywordsHand-eye calibrationTool offset calibrationThe least square method 

A Flexible Hand-Eye and Tool Offset Calibration Approach Using the Least Square Method


 This paper presents a modified evolutionary topology optimization method for designing compliant constant force mechanismS (CFMs). CFM is defined as mechanism that can generate constant force in the desired input displacement range, which is known as constant force range. The force variation, i.e. fluctuation of output forces over the constant force range, is a critical parameter, which reflects the stability of the output force. The key idea of the new method is that the design variables are increased or decreased for a certain small value instead of being changed between 0 (or x_{min} ) and 1 in other evolutionary structural optimization (ESO) method. As the CFMs have to experience a large deformation when it works, the influence of the nonlinearity need to be considered. An additive hyperelasticity technique is utilized to alleviate the instability of the finite element analysis, which is introduced by the low stiffness elements. The numerical examples show that the proposed design method can generate CFMs with desired constant force range and aspect ratio. The optimized CFM is manufactured by the 3D printing and the experimental result indicates that it can output an almost constant force(force variation ≤=2%) in a large relative constant force range(56.7%).

Topology Optimization Method for Designing Compliant Mechanism with Given Constant Force Range

Atomic force microscopy (AFM) generally scans the sample surface following a raster pattern signal, which contains discontinuities at turning points and frequencies beyond mechanical bandwidth of scanning stage. Consequently, raster scanning at high speed brings distortions to the resulting image. This paper describes a non-raster scanning method based on Cassini oval pattern. In this method, by adopting Cassini oval pattern, the input control signals of the two axes of scanner are replaced by sinusoid-like smooth signals, thereby reducing the harmonic vibration and improving scanning bandwidth. In addition, details on how to formulate the scanning pattern and generate the Cassini oval signals are analyzed. Experimental results of implementing this method in a commercial AFM and a compensated piezoelectric scanner indicate its feasibility on imaging.

Cassini Oval Scanning for High-Speed AFM Imaging

Topology optimization has been employed for the configurational design of flexure hinges under linear assumption in recent years. This paper presents a method for the design of flexure hinges with large displacements in which the nonlinear topology optimization is adopted. An optimization model is developed based on the spring model. The objective function is formulated by minimizing the stiffness in the desired direction. A rotational index is proposed and serves as one of the constraints for accomplishing the high precision revolute requirement. A symmetry constraint is employed to improve the practicability of the optimized results. A minimal length scale control technique is adopted to avoid point flexure issue. Several numerical results are performed to demonstrate the effectiveness of the proposed method.

Design of Flexure Hinges Using Geometrically Nonlinear Topology Optimization

In the micro-/nanomanipulation process, the detection of micro-forces is essential not only for sample protection but also for mechanical property tests. In general, optical fiber sensors have excellent sensitivities so they can be used as a kind of new sensing element for microforce sensor design. This article proposes a cantilever-type fiber Bragg grating (FBG)-based microforce sensor with micro-Newton resolution. A complete theoretical model is proposed to establish the mapping between the optical wavelength and the external force, and simulations are also carried out. A series of experiments are performed to evaluate the sensor, which agrees well with the calculation results, showing the sensor has the resolution of 7 $\mu \text{N}$ force in the range of 10 mN. Finally, the calibrated sensor is applied in a micro-/nanomanipulation system to achieve the mechanical property test of the zebrafish embryo. The result fits well with the reference results, proving the microforce sensor has the capability of measuring the mechanical property of the biological sample.

Benliang Zhu

Papers

A Flexible Hand-Eye and Tool Offset Calibration Approach Using the Least Square Method

Topology Optimization Method for Designing Compliant Mechanism with Given Constant Force Range

Cassini Oval Scanning for High-Speed AFM Imaging

Design of Flexure Hinges Using Geometrically Nonlinear Topology Optimization

Development of a Microforce Sensor Based on a Fiber Bragg Grating Used for Micro-/Nanomanipulation