This paper presents a design guidance of jig/fixture for flexible manufacturing system based on the verification of a base assembly motion instability. In flexible assembly system, the base assembly needs to be maintained in its assembled state without being taken apart. This requires stability in motion while the base assembly is handled or tilted. Therefore, the instability of the base assembly motion should be considered when determining the guide line of designing jig/fixture by evaluating a degree of the motion instability of the base assembly. To derive the instability, first we inference collision free assembly directions by extracting separable directions for the mating parts and calculate the separability which gives informations as to how the parts can be easily separated. Using these results, we determine the instability evaluated by summing all the modified separabilities of each component part within base assembly.

In this paper, we present a design, analysis, fabrication and performance test of the novel DoD metal-jet system for application to the high-density and high-temperature-melting materials. The theoretical analysis of the metal-jet nozzle system is derived by using electro-mechanical analogy. Based on the theoretical analysis results, we design the metal-jet print head system and fabricate the metal-jet system, which can eject the droplet of lead-free metal solder in high-temperature. In the experimental test, we set up the test apparatus for visualization of the droplet ejection and measure the ejected droplet volume and velocity. As a result, the diameter, volume and the velocity of the ejected droplet are about 65 $\mu$m $\sim$ 70 $\mu$m, 145p1 $\sim$ 180 pl and 4m/s, which shows quite good agreement with the theoretical analysis results of the 75 $\mu$m-diameter and 220 pl-volume of droplet. In comparison with the experimental result, the errors of diameter and volume are 7% $\sim$ 13% and 18 $\sim$ 34%, respectively.

Linear motor is easily affected by load disturbance, force ripple, friction, and parameter variations because there is no mechanical transmission to reduce the effects of model uncertainties and external disturbance. These nonlinear effects have been reduced for high-speed/high-accuracy position control either through the better motor design or via the better control algorithm that can compensate the nonlinear effects. In this paper, a nonlinear adaptive control algorithm is designed and applied for the position control of permanent magnet linear synchronous motor. In order to estimate and compensate the nonlinear effects such as friction and force ripple, the estimation and the nonlinear adaptive control laws are derived based on the virtual control input and a suitable Lyapunov function. The proposed controller is evaluated through the computer simulations. The control algorithm is also implemented to a DSP board and interfaced to the PMLSM for verifying the realtime control performance.

The vehicle of urban transit is a complex system that consists of various electric, electronic, and mechanical equipments, and the maintenance cost of this complex and large-scale system generally occupies sixty percent of the LCC (Life Cycle Cost). For reasonable establishing of maintenance strategies, safety security and cost limitation must be considered at the same time. The concept of system reliability has been introduced and optimized as the key of reasonable maintenance strategies. For optimization, three preceding studies were accomplished; standardizing a maintenance classification, constructing RBD (Reliability Block Diagram) of VVVF (Variable Voltage Variable Frequency) urban transit, and developing a web based reliability evaluation system. Historical maintenance data in terms of reliability index can be derived from the web based reliability evaluation system. In this paper, we propose applying inverse problem analysis method and hybrid neuro-genetic algorithm to system reliability optimization for using historical maintenance data in database of web based system. Feed-forward multi-layer neural networks trained by back propagation are used to find out the relationship between several component reliability (input) and system reliability (output) of structural system. The inverse problem can be formulated by using neural network. One of the neural network training algorithms, the back propagation algorithm, can attain stable and quick convergence during training process. Genetic algorithm is used to find the minimum square error.

This paper presents mechanical design, fabrication and test of a biomimetic fish robot actuated by a unimorph piezoceramic actuator, LIPCA(Lightweight Piezo-Composite curved Actuator.) We have designed a linkage mechanism that can convert bending motion of the LIPCA into the caudal fin movement. This linkage system consists of a rack-pinion system and four-bar linkage. Four types of artificial caudal fins that resemble caudal fin shapes of ostraciiform subcarangiform, carangiform, and thunniform fish, respectively, are attached to the posterior part of the robotic fish. The swimming test under 300 $V_{pp}$ input with 0.6 Hz to 1.2 Hz frequency was conducted to investigate effect of tail beat frequency and shape of caudal fin on the swimming speed of the robotic fish. At the frequency of 0.9 Hz, the maximum swimming speeds of 1.632 cm/s, 1.776 cm/s, 1.612 cm/s and 1.51 cm/s were reached for fish robots with ostraciiform, subcarangiform carangiform and thunniform caudal fins, respectively. The Strouhal number, which means the ratio between unsteady force and inertia force, or a measure of thrust efficiency, was calculated in order to examine thrust performance of the present biomimetic fish robot. The calculated Strouhal numbers show that the present robotic fish does not fall into the performance range of a fast swimming robot.

A new electric coil design methodology using the notion of topology optimization is developed. The specific design problem in consideration is to find optimal coil configuration that maximizes the Lorentz force under given magnetic field. Topology optimization is usually formulated using the finite element method, but the novel feature of this method is that no such partial differential equation solver is employed during the whole optimization process. The proposed methodology allows the determination of not only coil shape but also the number of coil turns which is not possible to determine by any existing topology optimization concept and to perform single coil strand identification algorithm. The specific applications are made in the design of two-dimensional fine-pattern focusing coils of an optical pickup actuator. In this method, the concept of equivalent magnetizing current is utilized to calculate the Lorentz force, and the optimal coil configuration is obtained without any initial layout. The method is capable of generating the location and shape of turns of coil. To confirm the effectiveness of the proposed method in optical pickup applications, design problems involving multipolar permanent magnets are considered.

Nickel nano and microstructures are fabricated with simple process. The fabrication process consists of nickel deposition, lithography, nickel ion etching and plasma ashing. Well-aligned nickel nanowalls and nickel self-encapsulated microchannels were fabricated. We found that the ion etching condition as a key fabrication process of nickel nanowalls and self-encapsulated microchannels, i.e., 40 sccm Ar flow, 550 W RF power, 15 mTorr working pressure, and $20^{\circ}C$ water cooled platen without using He backside cooling unit and with using it, respectively. We present the experimental results and discuss the formational conditions and the effect of nickel redeposition on the fabrication of nickel nano and microstructures.

Recently simulation model becomes an essential tool for analysis and design of a system but it is often expensive and time consuming as it becomes complicate to achieve reliable results. Therefore, high-fidelity simulation model needs to be replaced by an approximate model, the so-called metamodel. Metamodeling techniques include 3 components of sampling, metamodel and validation. Cross-validation approach has been proposed to provide sequnatially new sample point based on cross-validation error but it is very expensive because cross-validation must be evaluated at each stage. To enhance the cross-validation of metamodel, sequential sampling method using candidate points and representative cross-validation is proposed in this paper. The candidate and representative cross-validation approach of sequential sampling is illustrated for two-dimensional domain. To verify the performance of the suggested sampling technique, we compare the accuracy of the metamodels for various mathematical functions with that obtained by conventional sequential sampling strategies such as maximum distance, mean squared error, and maximum entropy sequential samplings. Through this research we team that the proposed approach is computationally inexpensive and provides good prediction performance.

Micromanipulator is a device that manipulates an object with high precision. Generally, a parallel-type robot has inherently higher precision than a serial-type robot. In most cases, the use of flexure hinge mechanisms is the most appropriate approach to micromanipulators. The micromanipulator is basically required that have high natural frequency and sufficient workspace. However, previous designs are hard to satisfy the required workspace and natural frequency, simultaneously, because the previous micromanipulators are coupled designs. Therefore, this paper suggests a new design parameter as displacement amplifier and new design procedure based on semi-coupled design in axiomatic design. As a consequence the spatial 3-DOF micromanipulator which is chosen as an exemplary device has natural frequency of 500Hz and workspace of $-0.5^{\circ}{\sim}0.5^{\circ}$. To investigate the effectiveness of the displacement amplifier, simulation and experiment are performed.

Elastic-plastic fracture mechanics is popularly used for integrity evaluation of major components, however, it is not easy to extract standard specimens from operating facility. This paper examines how ductile fracture toughness is characterized by a small punch testing technique in conjunction with finite element analyses incorporating a damage model. At first, micro-mechanical parameters constituting Rousselier model are calibrated for typical nuclear materials using both estimated and experimental load-displacement (P-$\delta$) curves of miniaturized specimens. Then, fracture resistance (J-R) curves of relatively larger standard CT specimens are predicted by finite element analyses employing the calibrated parameters and compared with corresponding experimental ones. It was proven that estimated results by the proposed method using small punch specimen is promising and might be used as a useful tool for ductile crack growth evaluation.

Axiomatic Design has been developed as a general design framework during past two decades and TRIZ has been developed for a design tool over 50 years. Axiomatic design is quite excellent in that design should be decoupled. When a design matrix is established, the characteristics of the design are identified according to the coupling properties. If the design is coupled, a decoupling process should be found. However, axiomatic design does not specifically indicate how to decouple a coupled design. In this research, the coupling manner is classified into six patterns. Each pattern could be solved by an appropriate TRIZ module. A table, which matches the coupling pattern and a TRIZ module, is proposed for effective application of the two design theories. The decoupling ideas are proposed by using TRIZ modules. When the number of decoupled designs is more than one, the engineer should select the final idea. The proposed method is applied to practical cases such as a tape feeder and a beam adjuster of the laser marker.

A volume integral equation method (VIEM) is applied for the effective analysis of plane elastostatic problems in unbounded solids containing single isotropic inclusion of two different shapes considering composite fiber volume fraction. Single cylindrical inclusion and single square cylindrical inclusion are considered in the composites with six different fiber volume fractions (0.25, 0.30, 0.35, 0.40, 0.45, 0.50). Using the rule of mixtures, the effective material properties are calculated according to the corresponding composite fiber volume fraction. The analysis of plane elastostatic problems in the unbounded effective material containing single fiber that covers an area corresponding to the composite fiber volume fraction in the bounded matrix material are carried out. Thus, single fiber, matrix material with a finite region, and the unbounded effective material are used in the VIEM models for the plane elastostatic analysis. A detailed analysis of stress field at the interface between the matrix and the inclusion is carried out for single cylindrical or square cylindrical inclusion. Next, the stress field is compared to that at the interface between the matrix and the single inclusion in unbounded isotropic matrix with single isotropic cylindrical or square cylindrical inclusion. This new method can also be applied to general two-dimensional elastodynamic and elastostatic problems with arbitrary shapes and number of inclusions. Through the analysis of plane elastostatic problems, it will be established that this new method is very accurate and effective for solving plane elastic problems in unbounded solids containing inclusions considering composite fiber volume fraction.

Vibration analysis of a rigid body supported by in-parallel linear springs can be greatly simplified by utilizing the conditions for a plane of symmetry. The vibration modes of an oscillatory system having plane of symmetry are classified into the in-plane and out-of-plane modes. From the viewpoint of screw theory, they represent respectively the vibration axes perpendicular to the plane of symmetry and lying in the plane of symmetry. In this paper, the sets of orthogonal and mutually intersecting three springs are used as resilient support of a rigid body. The geometrical conditions for the system to have a plane of symmetry and diagonalized stiffness matrix are presented. From the orthogonality of the vibration modes with respect to the inertia matrix, the geometrical relation between the reaction wrenches and the vibration modes are derived. This geometrical relation is then used to get the cubic design equation for the design of out-of-plane modes. The numerical design example of engine mounts is presented in order to explain the suggested design technique.

The linkage framework of geometric modeling based on NURBS(Non-Uniform Rational B-Spline) surface and shell finite analysis is developed in the present study. For this purpose, geometrically exact shell finite element is implemented. NURBS technology is employed to obtain the exact geometric quantities for the analysis. Especially, because NURBS is the most powerful and wide-spread method to represent general surfaces in the field of computer graphics and CAD(Computer Aided Design) industry, the direct computation of surface geometric quantities from the NURBS surface equation without approximation shows great potential for the integration between geometrically exact shell finite element and geometric modeling in the CAD systems. Some numerical examples are given to verify the performance and accuracy of the developed linkage framework. In additions, trimmed surfaces with some cutouts are considered for more practical applications.

Design optimization of layered plates bonding process is conducted by considering uncertainties in a manufacturing process, in order to reduce the crack failure arising due to the residual stress at the surface of the adherent which is caused by different thermal expansion coefficients. Robust optimization is peformed to minimize the mean as well as its variance of the residual stress, while constraining the distortion as well as the instantaneous maximum stress under the allowable reliability limits. In this optimization, the dimension reduction (DR) method is employed to quantify the reliability such as mean and variance of the layered plate bonding. It is expected that the DR method benefits the optimization from the perspectives of efficiency, accuracy, and simplicity. The obtained robust optimal solution is verified by the Monte Carlo simulation.

Enhanced lower order shear deformation theory is developed in this study. Generally, lower order theories are not adequate to predict accurate deformation and stress distribution through the thickness of laminated plate. For the accurate prediction of detailed stress and deformation distributions through the thickness, higher order zigzag theories have been proposed. However, in most cases, simplified zigzag higher order theory requires $C_1$, shape functions in finite element implementation. In commercial FE softwares, $C_1$, shape functions are not so common in plate and shell analysis. Thus zigzag theories are useful for the highly accurate prediction of thick composite behaviors but they are not practical in the sense that they cannot be used conveniently in the commercial package. In practice, iso-parametric $C_0$ plate model is the standard model for the analysis and design of composite laminated plates and shells. Thus in the present study, an enhanced lower order shear deformation theory is developed. The proposed theory requires only $C_0$ shape function in FE implementation. The least-squared energy error between the lower order theory and higher order theory is minimized. An enhanced lower order shear deformation theory(ELSDT) in this paper is proposed for smart structure under complex loadings. The ELSDT is constructed by the strain energy transformation and fully coupled mechanical, electric loading cases are studied. In order to obtain accurate prediction, zigzag in-plane displacement and transverse normal deformation are considered in the deformation Held. In the electric behavior, open-circuit condition as well as closed-circuit condition is considered. Through the numerous examples, the accuracy and robustness of present theory are demonstrated.

In this paper, a modified sensitivity control for the semi-active suspension system with a magneto-rheological (MR) damper is investigated. A 2-d.o.f quarter-car model together with a 6th order polynomial model for the MR damper is considered. For the purpose of suppressing the vertical acceleration of the sprung mass, the square of the vertical acceleration is defined as a cost function and a modified sensitivity control that updates the current input in the negative gradient of the cost function is proposed. The implementation of the proposed algorithm requires only the measurement of the relative displacement of the suspension deflection. The local stability of equilibria of the closed loop nonlinear system is proved by investigating the eigenvalues of the linearized ones. Through simulations, the passive suspension, the skyhook control, and the proposed modified sensitivity control are compared.

This paper presents development of carbon nanotube (CNT) tip modified by focused ion beam (FIB) and experimental results in non-contact mode of atomic force microscopy (AFM) using fabricated tip. We used an electric field which causes dielectrophoresis, to align and deposit CNTs on a conventional silicon tip. The morphology of the fabricated CNT tip was then modified into a desired shape using focused ion beam. We measured anodic aluminum oxide sample and trench structure to estimate the performance of FIB-modified tip and compared with those of conventional Si tip. We demonstrate that FIB modified tip in non contact mode had superior characteristics than conventional tip in the respects of wear, image resolution and sidewall measurement.