• Journal of Institute of Control, Robotics and Systems
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• v.17 no.8
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• pp.790-798
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• 2011

An efficient sequential computation algorithm of kinematic optimal control is suggested for redundancy resolution of freefloating manipulators. Utilization of minimum principle usually requires involved and tedious procedure of differentiation of Hamiltonian. Due to the constraints of momentum conservation, it is not easy to get exact differential equations of boundary value problem for even relatively simple free-floating manipulator models. To overcome this difficulty, we developed an effective sequential algorithm for the computation of terms appeared in the differential equations. The usefulness of suggested approach is verified by simulation of a planar 3-joints free-floating manipulator.

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.1578-1583
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• 2003

Time-Optimal solutions for attitude control with reaction wheels as well as with thrusters are studied. The suggested varying-time-sharing ratio thrusting is found to reduce the maneuvering time enormously. The hybrid control such as sequential hybrid and simultaneous hybrid with reaction wheels and thrusters are considered. The results show that simultaneous hybrid method reduces the maneuver time very much. Spacecraft model is KOrea Multi-Purpose SATellite(KOMPSAT)-II, which is being developed by KARI in KOREA as an agile maneuvering satellite.

• 한국연소학회:학술대회논문집
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• 2003.05a
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• pp.153-158
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• 2003

Catalytic Combustion used to be applied to specific conditions because of the characteristics different from flame combustion. However, many researches are focused on widening the applicant range of catalytic combustion with the competences of catalytic combustion. The development of many catalytic combustion appliances is one of the trials to overcome the restrictions of reaction and maximize the merits. In this research, past developments of appliances are depicted and new conceptual system will be introduced - sequential system. Sequential catalytic combustion system is composed of units - existing catalytic heat exchangers. This system is performed with parallel in composition and serially in operation. First, the burden of the preheating can be dramatically reduced. Second, stable operation control is expected. Lastly, Capacity expansion is flexible.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.1
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• pp.109-116
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• 2008

Model matching problem of asynchronous sequential machines is addressed in this paper. The main topic is to design a corrective controller such that the closed-loop behavior of the asynchronous sequential machine can follow a given model, i.e., their models can be "matched" in stable states. In particular, we assume that the considered asynchronous machine suffers from the presence of an input disturbance that can cause undesirable state transitions. The proposed controller can realize both model matching and elimination of the adverse effect of the input disturbance. Necessary and sufficient condition for the existence of a corrective controller that solves model matching problem is presented. Whenever controller exists, algorithms for their design are outlined and demonstrated in a case study.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.3
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• pp.1393-1405
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• 2017

It is well known that duty-cycling control by dynamically adjusting the polling interval according to the traffic loads can effectively achieve power saving in wireless sensor networks. Thus, there has been a significant research effort in developing polling interval adaptation schemes. Especially, Dynamic Low Power Listening (DLPL) scheme is one of the most widely adopted open-looping polling interval adaptation techniques in wireless sensor networks. In DLPL scheme, if consecutive idle (busy) samplings reach a given fixed threshold, the polling interval is increased (decreased). However, due to the trial-and-error based approach, it may significantly deteriorate the system performance depending on given threshold parameters. In this paper, we propose a novel DLPL scheme, called SDL (Sequential hypothesis testing based Dynamic LPL), which employs sequential hypothesis testing to decide whether to change the polling interval conforming to various traffic conditions. Simulation results show that SDL achieves substantial power saving over state-of-the-art DLPL schemes.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.34 no.1
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• pp.1-9
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• 1985

In this study we described Binary-Decision Method Programmable Controller that is faster than conventional Programmable Controller (P.C) using the Boolean method. An algorithm for the optimal BD program was systematically developed by using the incomplete multiple output function and the residual characteristic function. The potential applications of BD programmable controller for the problems of industrial control were illustrated, which include on-off sequential control function and also the tasks involving continuous data processing and PID control. An example was presented that has shown how BD programmable controller and ICU (Industrial Control Unit) controller can be applied to the sequential logics.

• Transactions of Materials Processing
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• v.20 no.3
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• pp.206-213
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• 2011

A flexible die, which is composed of a number of punches with adjusted heights to form a three-dimensional curved surface, is a crucial part of a flexible forming technology. In this study, the punch and control system of the flexible die were designed. The flexible die is divided into three modules, namely, punch, control and joint, and the corresponding modules were developed. The punch module materializes a three-dimensional forming surface by the control module, which is composed of an AC servo motor set and a linear guide. The joint module is necessary for the sequential motion between the servo motor set and the punch module. A sequential motion algorithm for the AC servo motor set, that uses the data of the punch relative heights, was also proposed. Finally, a flexible stretch forming test was carried out using the presently designed flexible die.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.4
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• pp.153-158
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• 2008

When we design the control system used Programmable Logic Controller(PLC), we program the main algorithm by Ladder Diagram(LD) in many standard language. But if we use an Sequential Function Chart(SFC), we is easy to know the sequential flow of control, to maintenance the controller and to describe a program. Even though a SFC have many merits, A SFC have some problems like a condition and a function of self test. Therefore this thesis show an efficient function of self test and we confirmed its feasibility through actual example.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.5
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• pp.55-61
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• 2010

When we design the control system used Programmable Logic Controller(PLC) by Sequential Function Chart(SFC), if we use a SFC, it is easy to know the sequential flow of control, to maintenance the controller and to describe a program. We program a SFC by a unique sequence, an alternative sequence and a parallel sequence. If we program a SFC by a alternative sequence, the memory size of a alternative sequence must be larger than the memory size of a unique sequence. Therefore this thesis show an efficient method to reduce a memory size and we confirmed its feasibility through actual example.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.7 no.2
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• pp.126-130
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• 2006

Programmable Logic Controller(PLC) is the most widely utilized and plays an important role in industrial control system. Sequential Function Chart(SFC) is a graphic language which is suitable for describing a sequential control logic in discrete control system. We can design a distribute control construction and a hierarchical control construction in process control system described by SFC. In hierarchical control structure, we construct each subsystems to synchronize a synchronous signal between subsystems, and the command system gives and takes a synchronous signal with subsystems. Therefore, the system has a low memory efficiency and a low system performance. In this paper, we propose the method that improved the efficiency of memory in hierarchical control construction, and confirm its feasibility through an actual example.