An Optimization Method for Design of Subambient Pressure Shaped Rail Sliders

1999 ◽  
Vol 121 (3) ◽  
pp. 575-580 ◽  
Author(s):  
Dong-Hoon Choi ◽  
Tae-Sik Kang
Keyword(s):  
Design Methodology ◽  
Optimization Method ◽  
Flying Height ◽  
Air Bearing ◽  
Bearing Surface ◽  
Programming Technique ◽  
Design Synthesis ◽  
Method Of Feasible Directions ◽  
Design Variables ◽  
Simulation Results

This study proposes a design methodology for determining configurations of subamient pressure shaped rail sliders by using a nonlinear programming technique in order to meet the desired flying characteristics over the entire recording band. The desired flying characteristics considered in this study are to minimize the variation in flying height from a target value, to keep the pitch angle within a suitable range, and to ensure that the outside rail flies lower than the inside rail even with the roll distribution due to manufacturing process. The design variables selected are recess depth, geometry of the air bearing surface, and pivot location in the transverse direction of the slider. The method of feasible directions in Automated Design Synthesis (ADS) is utilized to automatically find the optimum design variables which simultaneously meet all the desired flying characteristics. To validate the suggested design methodology, a computer program is developed and applied to a 30 percent/15 nm twin rail slider and a 30 percent/15 nm tri-rail slider. Simulation results for both sliders demonstrated the effectiveness of the proposed design methodology by showing that the flying characteristics of the optimally designed sliders are enhanced in comparison with those of the initial ones.

Trajectory Optimization Applied to Space Rendezvous

2013 ◽  
Vol 756-759 ◽  
pp. 3466-3470
Author(s):  
Xu Min Song ◽  
Qi Lin
Keyword(s):  
Simulated Annealing ◽  
Optimization Model ◽  
Trajectory Optimization ◽  
Optimization Problem ◽  
Optimization Method ◽  
Nonlinear Constraints ◽  
Design Variables ◽  
Adaptive Simulated Annealing ◽  
Simulation Results

The trajcetory plan problem of spece reandezvous mission was studied in this paper using nolinear optimization method. The optimization model was built based on the Hills equations. And by analysis property of the design variables, a transform was put forward , which eliminated the equation and nonlinear constraints as well as decreaseing the problem dimensions. The optimization problem was solved using Adaptive Simulated Annealing (ASA) method, and the rendezvous trajectory was designed.The method was validated by simulation results.

Probabilistic Designs of Air-Bearing Surface on Manufacturing Tolerances

2004 ◽  
Author(s):  
Sang-Joon Yoon ◽  
Dong-Hoon Choi
Keyword(s):  
Design Optimization ◽  
Reliability Analysis ◽  
Computation Time ◽  
Probabilistic Constraints ◽  
Air Bearing ◽  
Probabilistic Design ◽  
Bearing Surface ◽  
Deterministic Optimization ◽  
Design Variables ◽  
Conventional Optimization

The focus in this paper is to automatically design the air-bearing surface (ABS) considering the randomness of its geometry as an uncertainty of design variables. Designs determined by the conventional optimization could only provide a low level of confidence in practical products due to the existence of uncertainties in either engineering simulations or manufacturing processes. This calls for a reliability-based approach to the design optimization, which increases product or process quality by addressing randomness or stochastic properties of design problems. In this study, a probabilistic design problem is formulated considering the reliability analysis which is employed to estimate how the fabrication tolerances of individual slider parameters affect the final flying attitude tolerances. The proposed approach first solves the deterministic optimization problem. Beginning with this solution, the reliability-based design optimization (RBDO) is continued with the probabilistic constraints affected by the random variables. Probabilistic constraints overriding the constraints of the deterministic optimization attempt to drive the design to a reliability solution with minimum increase in the objective. The simulation results of the probabilistic design are directly compared with the values of the initial design and the results of the deterministic optimum design, respectively. In order to show the effectiveness of the proposed approach, the reliability analyses by the Monte Carlo simulation are carried out. And the results demonstrate how efficient the proposed approach is, considering the enormous computation time of the reliability analysis.

Optimal Shape Design for Heat Convection Problems Using NURBS

2009 ◽  
Author(s):  
Farbod Fakhrabadi ◽  
Farshad Kowsary
Keyword(s):  
Design Methodology ◽  
Optimization Method ◽  
Optimal Shape ◽  
Heat Convection ◽  
Curvilinear Coordinates ◽  
Shape Design ◽  
Control Points ◽  
Optimal Shape Design ◽  
Design Variables ◽  
Nurbs Surfaces

This article presents an optimal shape design methodology for heat convection problems. In this study, the shape of the convective medium is parameterized by means of non-uniform rational B-spline (NURBS) surfaces, and their control points represent the design variables. The convective domain is discretized by choosing the parameters of NURBS surfaces as generalized curvilinear coordinates, and the conservation equations are solved using the finite difference method. The simplified conjugate-gradient method (SCGM) is used as the optimization method to obtain the optimal shape and adjust the design variables intelligently. The methodology is demonstrated by optimizing the shape profile of a natural convective cavity with the objective of reducing the maximum wall temperature.

A recursive implementation of the ALIENOR optimization method

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Daniele Peri
Keyword(s):  
Design Methodology ◽  
Large Scale ◽  
Optimization Problem ◽  
Design Space ◽  
Optimization Method ◽  
Fine Tuning ◽  
Content Type ◽  
Design Variables ◽  
Scale Optimization ◽  
Similar Paper

PurposeA recursive scheme for the ALIENOR method is proposed as a remedy for the difficulties induced by the method. A progressive focusing on the most promising region, in combination with a variation of the density of the alpha-dense curve, is proposed.Design/methodology/approachALIENOR method is aimed at reducing the space dimensions of an optimization problem by spanning it by using a single alpha-dense curve: the curvilinear abscissa along the curve becomes the only design parameter for any design space. As a counterpart, the transformation of the objective function in the projected space is much more difficult to tackle.FindingsA fine tuning of the procedure has been performed in order to identity the correct balance between the different elements of the procedure. The proposed approach has been tested by using a set of algebraic functions with up to 1,024 design variables, demonstrating the ability of the method in solving large scale optimization problem. Also an industrial application is presented.Originality/valueIn the knowledge of the author there is not a similar paper in the current literature.

scholarly journals New Designs of HDD Air-Lubricated Sliders Via Topology Optimization

2004 ◽  
Vol 126 (1) ◽  
pp. 171-176 ◽  
Author(s):  
Chung-Jen Lu ◽  
Tai-Kuo Wang
Keyword(s):  
Topology Optimization ◽  
Optimal Design ◽  
Hard Disk Drives ◽  
Optimal Solution ◽  
Optimization Method ◽  
Uniform Mesh ◽  
Optimal Size ◽  
Air Bearing ◽  
Bearing Surface ◽  
Initial Design

Optimization is an efficient tool for developing designs of slider air bearings that meet the strict performance demands of current hard disk drives. Previous studies in this field concentrated on determining the optimal size and shape of the air-bearing surface for a specified initial design. The resulting optimal design has the same topology as that of the initial design. Therefore, the performance of the final optimal solution depends strongly on the initial design, which is chosen either intuitively or inspired by already existing designs. In this study, a topology optimization method is developed for determining the optimal slider configuration. First, the air-bearing surface is discretized by a uniform mesh. The optimization consists in determining whether the material contained in each element should be removed or not. Then, a genetic algorithm is employed for the determination of the optimal solution from the possible candidates. An example is presented to demonstrate the effectiveness of the proposed approach. The resulting optimal design has a topology different from those of the initial designs and possesses improved performance.

Design Optimization of the Taper-Flat Slider Positioned by a Rotary Actuator

1995 ◽  
Vol 117 (4) ◽  
pp. 588-593 ◽  
Author(s):  
Sang-Joon Yoon ◽  
Dong-Hoon Choi
Keyword(s):  
Optimization Technique ◽  
Leading Edge ◽  
Flying Height ◽  
Air Bearing ◽  
Skew Angle ◽  
Optimum Configuration ◽  
Rotary Actuator ◽  
Design Variables ◽  
Augmented Lagrange Multiplier ◽  
Typical Configuration

In this paper, an optimization technique is utilized to find an optimum configuration of the taper-flat slider positioned by a rotary actuator for enhanced static air-bearing characteristics. The aim of optimization consists in simultaneously minimizing the variation in flying height from a target value, maximizing the smallest pitch angle, and minimizing the largest roll angle, over the entire magnetic recording band. As the design variables, the leading edge taper angle and rail width of a taper-flat slider, and the skew angle at the inside track are chosen since they seem to be the most influential parameters on air-bearing characteristics. The optimum design variables are automatically obtained by using the augmented Lagrange multiplier method, and the static characteristics of the optimally designed sliders are found to be superior to those of the taper-flat sliders of typical configuration over the entire recording band. Results obtained for three taper-flat slider models are reported, showing the effectiveness of the proposed design scheme.

A New Implicit Algorithm for the Simulations of Slider Dynamics Based on the Unstructured Triangular Mesh

2004 ◽  
Author(s):  
Wei Hua ◽  
Jianhua Li ◽  
Bo Liu ◽  
Yansheng Ma
Keyword(s):  
Triangular Mesh ◽  
Flying Height ◽  
Air Bearing ◽  
Implicit Algorithm ◽  
Rectangular Mesh ◽  
Unstructured Triangular Mesh ◽  
Simulation Results ◽  
Time Accuracy ◽  
Volume Method ◽  
D Model

The unstructured triangular mesh is successfully applied to the steady simulations of the slider due to its flexibility, accuracy and mesh efficiency in capturing various complex ABS rails and recess wall regions. This paper introduces a new implicit algorithm with second order time accuracy for the time-dependent simulations of the slider dynamics based on the unstructured triangular mesh. The new algorithm is specially developed for the unstructured triangular mesh and the finite volume method. It is applied to simulate the load/unload details based on the 9-D model, such as the influences of the limiter position on the flying height during the unload process, and the development and the 3-D profiles of the air bearing pressure during the load process. Because of the mesh efficiency of the unstructured triangular mesh and the flexibility of applying greater time steps, the simulation times are significantly shorter than those of the structured rectangular mesh. The simulation results based on the algorithm are in good correlation with the experimental results.

Probabilistic Designs of Air-Bearing Surface on Manufacturing Tolerances

2005 ◽  
Vol 127 (1) ◽  
pp. 149-154 ◽  
Author(s):  
Sang-Joon Yoon ◽  
Dong-Hoon Choi
Keyword(s):  
Design Optimization ◽  
Reliability Analysis ◽  
Computation Time ◽  
Probabilistic Constraints ◽  
Air Bearing ◽  
Probabilistic Design ◽  
Bearing Surface ◽  
Deterministic Optimization ◽  
Design Variables ◽  
Conventional Optimization

The focus in this paper is to automatically design the air-bearing surface (ABS) considering the randomness of its geometry as an uncertainty of design variables. Designs determined by the conventional optimization could only provide a low level of confidence in practical products due to the existence of uncertainties in either engineering simulations or manufacturing processes. This calls for a reliability-based approach to the design optimization, which increases product or process quality by addressing randomness or stochastic properties of design problems. In this study, a probabilistic design problem is formulated considering the reliability analysis which is employed to estimate how the fabrication tolerances of individual slider parameters affect the final flying attitude tolerances. The proposed approach first solves the deterministic optimization problem. Beginning with this solution, the reliability-based design optimization (RBDO) is continued with the probabilistic constraints affected by the random variables. Probabilistic constraints overriding the constraints of the deterministic optimization attempt to drive the design to a reliability solution with a minimum increase in the objective. The simulation results of the probabilistic design are directly compared with the values of the initial design and the results of the deterministic optimum design, respectively. In order to show the effectiveness of the proposed approach, the reliability analyses by the Monte Carlo simulation are carried out. And the results demonstrate how efficient the proposed approach is, considering the enormous computation time of the reliability analysis.

The Double Dimple Magnetic Recording Head Suspension and Its Effect on Fly Height Variability

1995 ◽  
Vol 117 (2) ◽  
pp. 267-271
Author(s):  
J. C. Harrison ◽  
K. P. Hanrahan
Keyword(s):  
Degrees Of Freedom ◽  
Initial Conditions ◽  
Flying Height ◽  
Air Bearing ◽  
Bearing Surface ◽  
Percent Reduction ◽  
Recording Head ◽  
Head Gimbal Assembly ◽  
Magnetic Recording Head ◽  
Fly Height

A gimbal forming modificaton is presented which, when implemented, leads to significant reduction in air bearing surface (ABS) static attitude and flying height variability within head-gimbal assembly (HGA) populations. The modification requires no additional parts or steps in the manufacture of the suspension assembly. An experimental test of the concept is described, along with the procedure on which it is based. The resulting reduction in product variability is obtained without measurement of (or tailoring to) the initial conditions of the constitutive parts of each HGA. A ≈ 50 percent reduction in static attitude variability, and a ≈ 33 percent reduction in flying variability, was experimentally shown to result from the adoption of the Double Dimple design concept, in all flying degrees of freedom.

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