• Nuclear Engineering and Technology
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• v.53 no.7
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• pp.2251-2260
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• 2021

The motion control of the divertor maintenance system of the China Fusion Engineering Test Reactor (CFETR) was studied in this paper, in which CFETR Multi-Functional Maintenance Platform (MFMP) was simplified as a parallel robot for the convenience of theoretical analysis. In order to design the motion controller of parallel robot, the kinematics analysis of parallel robot was carried out. After that, the dynamic modeling of the hydraulic system was built. As the large variation of heavy payload on MFMP and highly nonlinearity of the system, A Fuzzy-PID controller was built for self-tuning PID controller parameters by using Fuzzy system to achieve better performance. In order to test the feasibility of the Fuzzy-PID controller, the simulation model of the system was built in Simulink. The results have showed that Fuzzy-PID controller can significantly reduce the angular error of the moving platform and provide the stable motion for transferring the divertor.

• Proceedings of the Korean Vacuum Society Conference
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• 2003.08a
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• pp.219-219
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• 2003

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.77-77
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• 2012

As interest has increased in the interaction between low-temperature plasmas and materials, the role of modeling and simulation of processing in plasma has become important in understanding the effects of charged particles and radicals in plasma applications. Thus in this presentation, we present the theoretical and experimental studies of electron impact cross section for plasma processing gas, such as plasma etching and deposition processes. Also, here the work conducted at the Data Center for Plasma Properties (DCPP) over last 7 years on the systematic synthesis and assessment of fundamental knowledge on low-energy electron interactions with plasma processing gases is briefly summarized and discussed.

• Proceedings of the Korean Vacuum Society Conference
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• 2005.02a
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• pp.92-92
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• 2005

• Progress in Superconductivity and Cryogenics
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• v.23 no.4
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• pp.49-55
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• 2021

The Cable in Conduit Conductor (CICC) configurations are designed, tested and realized to make high field superconducting (SC) magnets. The evolution of CICC design makes it challenging to forecast thermo-hydraulic behavior. A common objective of thermo-hydraulic studies is to obtain the most reliable predictive correlation for friction factor in CICC geometries and to reduce the dependency on the experiment. So far, only the void fraction and Reynolds number have been considered in the predictive correlations in an explicit way. In the present paper, the CICC twisting pattern dependency, called tortuosity (τ), on the pressure drop prediction, has been assessed through a numerical simulation approach. The CICC twisting pattern with 6+1 petals (solid conductor in the present study) with different twisting pitches is mimicked in the numerical simulation for the range 100 ≤ Re ≤10000 and 1 < τ < 1.08 and a correlation for friction factor, f, has been proposed as a function of Re and τ.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.508-508
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• 2012

CST microwave studio is used to simulate the plasma profile of the 450mm CCP source. Standing wave effect becomes important at the high frequency as the electrode radius increases. To solve plasma non-uniformity problem, we designed multi electrode chamber to decreasing standing wave effect. Simulation showed the ratio of input power of each electrode is related with electric field strength. The multi electrode was constructed and measured by 2D probe arrays using floating harmonic method. Uniformity of 450 mm CCP was changed by the ratio of input power of each electrode. We described this dependence with circuit model.

• Proceedings of the KIEE Conference
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• 2006.10a
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• pp.158-159
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• 2006

The resistance-capacitance (RC) delay of signals through interconnection materials becomes a big hurdle for high speed operation of semiconductors which contain multilayer interconnection layers. In order to reduce the RC delay, low-k materials will be used for inter-metal dielectric (IMD) materials. We have developed self-consistent simulation tool that includes neutral-species transport model, based on the relaxation continuum (RCT) model. We present the parametric study of the modeling results of a two-frequency capacitively coupled plasma (2f-CCP) with $N_2/H_2$ gas mixture that is known as promising one for organic low-k materials etching. We include the neutral transport model as well as plasma one in the calculation. The plasma and neutrals are calculated self-consistently by iterating the simulation of both species till a spatiotemporal steady state profile could be obtained.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.53 no.8
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• pp.433-442
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• 2004

Various models and various boundary conditions have been suggested for fluid transport simulations of high density plasma discharges such as the inductively coupled plasma discharge. In this work, we compare the various models using one-dimensional simulations based on the FDM(finite difference method), the upwind scheme, the power-law scheme, and the dielectric relaxation scheme［l］ Comparing the exactness, the numerical stability and the efficiency of the various models. the most adoptable model is suggested.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.148-148
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• 2012

A cutoff probe is the novel diagnostic method to get the absolute plasma density with simple system and less assumption. However, high density of ion flux from plasma on probe tip can make the error of plasma density measurement because the dielectric material of probe tip can be damaged by ion flux. We proposed a shielded cutoff probe using the ceramic tube for protection from ion flux. The ceramic tube on probe tip can intercept the ion flux from plasma. The transmitted spectrum using the shielded cutoff probe is good agreement with E/M wave simulation result (CST Microwave Studio) and previous circuit simulation of cutoff probe [1]. From the analysis of the measured transmitted spectrum base on the circuit modeling, the parallel resonance frequency is same as the unshielded cutoff probe case. The obtained results of electron density is presented and discussed in wide range of experimental conditions, together with comparison result with previous cutoff method.

• Nuclear Engineering and Technology
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• v.56 no.2
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• pp.498-505
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• 2024

In this paper, a cable-driven endoscopic manipulator (CEM) is designed for the Chinese latest compact fusion reactor. The whole CEM arm is more than 3000 mm long and includes end vision tools, an endoscopic manipulator/control system, a feeding system, a drag chain system, support systems, a neutron shield door, etc. It can cover a range of ±45° of the vacuum chamber by working in a wrap-around mode, etc., to meet the need for observation at any position and angle. By placing all drive motors in the end drive box via a cable drive, cooling, and radiation protection of the entire robot can be facilitated. To address the CEM motion control problem, a discrete trajectory tracking method is proposed. By restricting each joint of the CEM to the target curve through segmental fitting, the trajectory tracking control is completed. To avoid the joint rotation angle overrun, a joint limit rotation angle optimization method is proposed based on the equivalent rod length principle. Finally, the CEM simulation system is established. The rationality of the structure design and the effectiveness of the motion control algorithm are verified by the simulation.