• Journal of Institute of Control, Robotics and Systems
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• v.7 no.11
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• pp.896-903
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• 2001

This study investigates the use of mixed $H_2/H_{$\infty}$ and $\mu$-synthesis to construct a robust controller for the benchmark problem. The model treated in the problem is a coupled three-inertial system that reflects the dynamics of mechanical vibrations. This kind of problem requires to be satisfied the robust performance (both in the time and frequency-domain specifications). We, first, adopt the mixed $H_2/H_{$\infty}$ theory to design a feedback controller K(s). Next, $\mu$-synthesis method is applied to the overall system to make use of structured parametric uncertainty. This process permits higher levels of controller authority and reduces the conservativeness of the controller. Finally, the feedforward controller is also used to improve the transient response of the output. We confirm that all design specifications except a complementary sensitivity condition can be achieved.

• Journal of Aerospace System Engineering
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• v.10 no.2
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• pp.14-21
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• 2016

In this study, we proposed a water rocket CULV-1 (Chosun University Launch Vehicle-1). Unlike a conventional water rocket, CULV-1 can perform the booster rocket, fairing, and payload separation like an actual launch vehicle and also the imaging data acquisition. The conceptual and critical design of the proposed CULV-1 have been performed considering the operation characteristics. The verification tests have been performed from subsystem to system level in accordance with the established test specifications and verification procedures. Through the final launch test of the flight model, we have verified the design effectiveness of the proposed separation mechanisms for water rocket applications and the mission requirements of the CULV-1 also have been complied.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.3 s.96
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• pp.180-188
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• 1999

${\mu}$-synthesis is applied to design a robust controller for a seeker scan loop system which has model uncertainty and is subject to a external disturbance due to abrupt missile maneuver. The issue of modelling a real-valued parametric uncertainty of a physical seeker scan loop system is discussed. The two-degree-of-frame control structure is employed to obtain better performance. It is shown that ${\mu}$-synthesis provides a superior framework for the robust control design of a seeker scan loop system which exhibits robust performance. The proposed robust control system satisfies design requirements, and especially shows good scanning performances for conical and rosette scan patterns despite parametric uncertainty in real system model.

• Bulletin of the Korean Chemical Society
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• v.25 no.11
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• pp.1648-1652
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• 2004

A set of unprecedented syndiospecific dimethyl- and diethylamino-functionalized polystyrenes was prepared by catalytically polymerizing the corresponding monomers using (pentamethylcyclopentadienyl)titanatrane/MMAO catalytic system. Dialkylamino-functionalized styrene monomers were synthesized by Wittig reaction from the corresponding aldehyde in high yield. The resulting polymers are soluble in polar organic solvents such as THF and show good thermal stability. The chemical transformation of the syndiospecific poly(4-diethylaminostyrene) also gave new polar polymers, namely syndiotactic poly(4-diethylaminostyrene hydrochloride), which is unattainable by traditional synthetic methods.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.110-110
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• 2001

By the state transformation including independent outputs functions, a nonlinear process model can be decomposed into two subsystems; the one(design model) is described in output variables as new states and used for control system synthesis and the other(disturbance model) is described in the original unavailable states and its couplings with the design model are treated as uncertain time-varying parameters in the design model. Its existence with respect to the design model is ignored. So, the design model is and uncertain time-variant system. Control synthesis based on a reduced design model is a combined form of a time-variant input-output linearization with parameter estimation. The parameter estimation is also based on the design model and it gives the parameter estimates such that the estimated outputs follow the actual outputs in a specified way. The disturbances form disturbance model and as well all the other uncertainties affecting the outputs will be reflected into the estimated parameters used in the linearizing control law.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.2 no.2
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• pp.115-119
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• 2001

The design and manufacture of injection molded polymeric parts with desired properties is a costly process dominated by empiricism, including the repeated modification of actual tooling. This paper presents an knowledge-based synthesis system which can predict the mechanical performance of a molded product and diagnose the design before the actual mold is machined. The knowledge-based system synergistically combines a rule-based system with CAE programs. Hueristic know]edge of injection molding. flow simulation, and mechanical performance prediction is formalized as rules of an expert consultation system. The expert system interprets the analytical results of the process simulation, predicts the performance, evaluates the design and generates recommendation for optimal design alternatives.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.31A no.2
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• pp.116-124
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• 1994

This paper describes the design of a high-level synthesis system. ISyn: Interface Synthesis System for ISPS-A. which generates hardware satisfying timing constraints. The original version of ISPS is extended to be used for the description/capture of interface operations and timing constraints in the ISPS-A. To generate the schedule satisfying interface constraints the scheduling process is divided into two steps:pre-scheduling and post-scheduling. ISyn allocates hardware modules with I/O ports by the clique partitioning algorithm. Experimental results show that ISyn is capable of synthesizing hardware modules effectively for internal and/or interactive operations.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.30A no.6
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• pp.49-57
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• 1993

In the paper, we describe the design of a pipelined datapath synthesis system for DSP applications. Taking SFG (Signal Flow Graph) in schematic as inputs, the system generates pipelined datapaths automatically through scheduling and module allocation processes. For efficient hardware synthesis, scheduling and module allocation algorithms are proposed. The proposed scheduling algorithm is of iterative/constructive nature, where the measure of equi-distribution of operations to partitions is adopted as the objective function. Module allocation is performed to reduce the interconnection cost from the initial allocation. In the experiment, we compare the results with those of other systems and show the effectiveness of the proposed algorithms.

• Journal of the Korean Institute of Telematics and Electronics C
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• v.34C no.6
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• pp.1-10
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• 1997

By considering low power design at higher levels of abstraction rather than at lower levels of abstraction, we can apply various transformation techniques to a system design with wider view and obtain much more effective power reduction with less cost and effort. In this paper, a transformation technique, called power - conscious loop folding is proposed for high level synthesis of a low power system.Our work is focused on reducing the power consumed by functional units in adata path dominated circuit through the decrease of switching activity. Te transformation algorithm has been implemented and integrated into HYPER, a high level synthesis system for experiments. In our experiments, we could achieve a pwoer reduction of up to 50% for data path dominated circuits.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2003.06a
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• pp.899-904
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• 2003

Tight integration of product design and process planning in the early design stage would make bigger impact as wider spectrum of design and manufacturing alternatives can be pursued and evaluated. Thus the development of systematic computer-based support for this integration is desirable. For this integration and process planning in the early design stage. the systematic method to synthesize shape of part from functional requirements is crucial. This research presents the methods of functional decomposition from overall function or product and synthesizing shape of part based on functional relations extracted from functional decomposition using planetary gear transmission system as an example.