• 유공압시스템학회논문집
• /
• 제5권1호
• /
• pp.13-19
• /
• 2008

The typical hydraulic system of hoist is composed of a hydraulic supply unit, a directional control valve, counter balance valve, and flow control valves. The flow capacity coefficients of flow control valves should be adjusted so that the hoist is operated at moderate speed and the hydraulic energy loss is minimized. However, it is difficult to adjust the flow coefficients of flow control valves by trial and error for optimal operation. Here, the steady state model of the hoist hydraulic system including the differential cylinder circuit is derived and the optimal flow capacity coefficients of flow control valves are obtained using the complex method that is one kind of constrained direct search method.

• 소음진동
• /
• 제5권2호
• /
• pp.183-195
• /
• 1995

The mathematical model of the gear reductioner which consists which consists of the geared rotor-bearing system containing case is developed, assuming as the lumped parameter system. Constraints for vibration suppresion as well as strength of gear teeth, and shaft and kinematic conditions in gear pairs are considered. To find the design parameters satisfing the proposed constraints, a direct search method modified by the technique of Taguchi's experimental scheduling is used. One and two stepped gear reductioners are designed so that the criticl speeds due to the gear transmission error are moved out of the operating speed range.

• 드라이브 ㆍ 컨트롤
• /
• 제11권4호
• /
• pp.32-38
• /
• 2014

The hydraulic fuse, which responds to the suddenly increased flow on rupture of a line and shuts off the fluid flow, would prevent large spillage of liquid. The quick-acting hydraulic fuse, which is mainly composed of a poppet, a seat, and a spring, must be designed to minimize the leaked flow and to prevent high collision speed between the poppet and seat during fuse operation on a line rupture. The optimal design parameters of a quick-acting hydraulic fuse were searched using the genetic algorithm and the complex method that are kinds of constrained direct search methods. The dynamic behavior of a quick-acting hydraulic fuse was researched using computer simulations that applied the obtained optimal design parameters.

• 드라이브 ㆍ 컨트롤
• /
• 제9권3호
• /
• pp.29-36
• /
• 2012

The hydraulic cylinder is used for actuating the roller-link type rotating floodgate which controls the volume of water in the reservoir. The locating points of hydraulic cylinder are restricted to the limited space and determined to minimize the cylinder force necessary for actuating the floodgate. Generally, the head end point of cylinder is fixed at underground and the rod end point of cylinder is connected to the support link. Therefore there exist three design variables to be determined to minimize the cylinder force within the rotating range of floodgate. First, the mathematical model of the roller-link type rotating floodgate is derived to find the cylinder force corresponding to the floodgate angle. Then, the optimal locating point of hydraulic cylinder is searched using the complex method that is one kind of constrained direct search method.

• 산업공학
• /
• 제8권1호
• /
• pp.23-30
• /
• 1995

Optimization in the engineering design is to select the best of many possible design alternatives in a complex design space. One major problem of local minimization algorithm is that they often result in local optima. In this paper, a hybrid method was developed by coupling the genetic algorithm and a traditional direct search method. The proposed method first finds a region for possible global optimum using the genetic algorithm and then searchs for a global optimum using the direct search method. To evaluate the performance of the hybrid method, it was applied to three test problems and a problem of designing corrugate bulkhead of a ship.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1998년도 하계학술대회 논문집 A
• /
• pp.70-72
• /
• 1998

This paper discusses the development of a new optimization algorithm for DC motor design. In principle, the new algorithm utilizes a mixed method that consists of genetic algorithms in conjunction with direct search method. The genetic algorithms are used for locating the global optimum region while the direct search method is used to achieve objective function convergence. In order to validate the effectiveness, the new algorithm has been applied to an actual DC motor. Field and torque characteristics of the DC motor are computed using finite element method and the principle of virtual work, respectively.

• 한국자동차공학회논문집
• /
• 제13권6호
• /
• pp.170-176
• /
• 2005

The hydraulic cylinder is used for actuating the sluice gate which controls the volume of water in the reservoir. The locating points of hydraulic cylinder are restricted to limited space and determined to minimize the cylinder force necessary for actuating the sluice gate. Generally, the head end point of cylinder is fixed at underground and the rod end point of cylinder is connected to the gate plate when it is fully opened. Therefore there exist three parameters to be determined to minimize the cylinder force in the operation range of sluice gate. The optimal locating points of hydraulic cylinder are obtained using the complex method that is one kind of constrained direct search m method.

• 조명전기설비학회논문지
• /
• 제24권10호
• /
• pp.149-156
• /
• 2010

In this paper, the optimal design of a wind generator, implemented with the hybridized GA(Genetic Algorithm) and ES(Expert System), has been performed to maximize the AEP(Annual Energy Production) over the whole wind speed characterized by the statistical model of wind speed distribution. In particular, to solve the problem of calculation iterate, ES finds the superior individual and apply to initial generation of GA and it makes reduction of search domain. Meanwhile, for effective searching in reduced search domain, it propose Intelligent GA algorithm. Also, it shows the results of optimized model 500[kW] wind generator using hybridized algorithm and benchmark result of compare with GA.

• Smart Structures and Systems
• /
• 제16권1호
• /
• pp.27-46
• /
• 2015

Active surface adjustment of cable net structures is becoming significant when large-size cable net structures are widely applied in various fields, especially in satellite antennas. A general-duty adjustment method based on active cables is proposed to achieve active surface adjustment or surface profile reconfiguration of cable net structures. Piezoelectric actuators and voice coil actuators are selected for constructing active cable structures and their simplified mechanical models are proposed. A bilevel optimization model of active surface adjustment is proposed based on the nonlinear static model established by the direct stiffness method. A pattern search algorithm combined with the trust region method is developed to solve this optimization problem. Numerical examples of a parabolic cable net reflector are analyzed and different distribution types of active cables are compared.

• Journal of the Korean Physical Society
• /
• 제73권12호
• /
• pp.1845-1848
• /
• 2018

We introduce a process for optically reconstructing full-color holographic images recorded by optical scanning holography. A complex RGB-color hologram was recorded and converted into a binary hologram using a direct binary search (DBS) algorithm. The generated binary hologram was then optically reconstructed using a spatial light modulator. The discrepancies between the reconstructed object sizes and colors due to chromatic aberration were corrected by adjusting the reconstruction parameters in the DBS algorithm. To the best of our knowledge, this represents the first optical reconstruction of a full-color hologram recorded by optical scanning holography.