• The Transactions of the Korean Institute of Power Electronics
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• v.7 no.5
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• pp.427-436
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• 2002

This paper presents an implementation of high-dynamic performance of position sensorless motion control system of Reluctance Synchronous Motor(RSM) drives for an industrial servo system with direct torque control(DTC). The problems of high-dynamic performance and maximum efficiency RSM drives controlled by DTC are saturation of stator linkage flux and nonlinear inductance characteristics with various load currents. The accurate estimation of the stator flux and torque are obtained using stator flux observer of which a saturated inductance $L_d$ and $L_q$ can be compensated by adapting from measurable the modulus of the stator current and rotor position. To obtain fast torque response and maximum torque/current with varying load current, the reference command flux is ensured by imposing $I_{ds} = I_{qs}$. This control strategy is proposed to achieve fast response and optimal efficiency for RSM drive. In order to prove rightness of the suggested control algorithm, the actual experiment carried out at $\pm$20 and $\pm$1500 rpm. The developed digitally high-performance motion control system shown good response characteristic of control results and high performance features using 1.0kW RSM which has 2.57 Ld/Lq salient ratio.

• The Journal of Korean Academy of Prosthodontics
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• v.48 no.4
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• pp.280-286
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• 2010

Purpose: This study evaluated the detorque values of screws in a multiple implant-supported superstructure using stone casts made with 2 different impression techniques. Material and methods: A fully edentulous mandibular master model and a metal framework directly connected to four implants (Br${\aa}$nemark $System^{(R)}$; Nobel Biocare AB) with a passive fit to each other were fabricated. Six experimental stone casts (Group 1) were made with 6 non-splinted impressions on a master cast and another 6 experimental casts (Group 2) were made with 6 acrylic resin splinted impressions. The detorque values of screws ($TorqTite^{(R)}$ GoldAdapt Abutment Screw; Nobel Biocare AB) were measured twice after the metal framework was fastened onto each experimental stone cast with 20 Ncm torque. Detorque values were analyzed using the mixed model with the fixed effect of screw and reading and the random effect of model for the repeated measured data at a .05 level of ignificance. Results: The mean detorque values were 7.9 Ncm (Group 1) and 8.1 Ncm (Group 2), and the mean of minimum detorque values were 6.1 Ncm (Group 1) and 6.5 Ncm (Group 2). No statistically significant differences between 2 groups were found and no statistically significant differences among 4 screws were found for detorque values. No statistically significant differences between 2 groups were also found for minimum detorque values. Conclusion: In a multiple external hexagon implant-supported prosthesis, no significant differences between 2 groups were found for detorque values and for minimum detorque values. There seems to be no significant differences in screw joint stability between 2 stone cast groups made with 2 different impression techniques.

• Journal of the korean Society of Automotive Engineers
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• v.11 no.4
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• pp.3-12
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• 1989

• Journal of the Korean Institute of Intelligent Systems
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• v.22 no.1
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• pp.36-41
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• 2012

This paper presents torque control of DC motor using the velocity profile based acceleration/deceleration controller for automatic guided vehicles (AGVs). This technique has some advantage; to reduce the damage of motors and to extend the life time of motors. First, we generate velocity profiles for three cases and design the state feedback controller using the generated velocity profile as a reference. The state feedback controller has servo system for solving regulation problem. For the verification, we apply the proposed method to control a cart position and shows some simulation result.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.37 no.1
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• pp.59-65
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• 2013

In this study, the effects of the compressor for the air conditioning system on the fuel economy were experimentally investigated in an actual automobile. This study aims to analyze the level of contribution of the driving torque of the compressor to the fuel economy. A torque sensor, which is directly set on the clutch of the compressor, is developed to obtain data about the compressor load, which influences the fuel efficiency, and then, the reliability of the torque sensor is verified by comparing the results with those of a torque meter in a bench test. An actual automobile equipped with the compressor and torque sensor is operated in a climate wind tunnel in which appropriate facilities are set up to evaluate the fuel efficiency. The compressor driving torque resulting from the difference in the compressor displacement is found to influence the fuel economy, and the fuel economy is found to be worsened by up to 2~3% with an around 11% increase in the compressor displacement under the same conditions.

• Transactions of the Korean Society of Mechanical Engineers
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• v.14 no.5
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• pp.1320-1329
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• 1990

A static performance tester for a torque rod assembly was developed to evaluate the three characteristics of the rod rubber bushing : radial spring characteristic, thrust spring characteristic, and rotational torque characteristic. Among the various schemes considered in the conceptual design stage, the final versatile type was determined to perform three different tests in one machine. The performance testing machine carried out radial spring test, thrust spring test, and torque test of the torque rod assembly. Static performance of the torque rod assembly was evaluated with the tester developed and fatigue strength of the assembly was also tested with the servo-hydraulic structural fatigue testing machine. The life of the component was found to be related with the rubber quality and adhesionability between the rubber and the steel rod. The optimum rubber hardness was experimentally found by changing the chemical compositions of rubber, and the adhesion was improved by optimizing the shape of the outer section of a the rubber, this study ensured the development of a reliable torque rod assembly.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.19 no.8
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• pp.33-39
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• 2005

The maximum output torque and power developed by the machine is ultimately depended on the allowable inverter current rating and maximum voltage which the inverter can supply to the machine. Therefore, considering the limited voltage and current capacities, it is desirable to consider a control method which yields the best possible torque per ampere. In this paper, we propose fuzzy neural network(FNN) controller that combines a fuzzy control and the neural network for high performance control of induction motor drive. This controller composes antecedence of the fuzzy rules and consequence by a clustering method and a multi-layer neural networks. This controller is compounding of advantages that robust control of a fuzzy control and high-adaptive control of the neural networks. Also, this paper is proposed control of maximum torque per ampere(MTPA) of induction moor. This strategy is reposed which is simple in structure and has the honest goal of minimizing the stator current magnitude for given load torque. The performance of the proposed induction motor drive with maximum torque control using FNN controller is verified by analysis results at dynamic operation conditions.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2017.04a
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• pp.15-15
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• 2017

본 연구는 필드 작업 시 작업조건에 따른 정식기의 PTO 부하를 측정하고, 이를 이용하여 작업조건에 따른 안전율 시뮬레이션을 목적으로 수행하였다. 부하 계측 시스템은 PTO 축의 부하를 측정하기 위한 토크 센서, 토크 센서에서 발생한 신호를 수집하기 위한 데이터 수집장치, 노트북에 전원을 공급하기 위한 파워 컨트롤러로 구성하였다. 토크센서에서 입력된 부하 데이터를 처리하기 위한 소프트웨어는 Labview(Version 2011, National Instrument, USA)를 사용하였다. 포장시험은 유사한 토양 조건에서 4회 반복 시험을 수행하였으며, 작업속도 고속 조건에서 4개의 주간거리(26, 35, 43, 80cm)와 3개의 식부깊이 (85, 105, 136mm)에 대하여 수행하였다. 안전율 시뮬레이션을 위한 소프트웨어는 KISSsoft(Version 2016, Kissling & Co. AG, Switzerland)를 사용하였다. 식부깊이 85mm에서 주간거리 26, 35, 43, 80cm일 때 작업시 각각 굽힘 안전율은 2.2874, 2.4507, 2.7139, 2.8064로 나타났으며 접촉 안전율은 1.1787, 1.2799, 1.3205, 1.3275로 나타났다. 식부깊이 105mm에서 주간거리 26, 35, 43, 80cm일 때 작업 시 각각 굽힘 안전율은 2.1261, 2.2781, 2.4879, 2.5866로 나타났으며 접촉 안전율은 1.1296, 1.1425, 1.2710, 1.2507로 나타났다. 식부깊이 136mm에서 주간거리 26, 35, 43, 80cm일 때 작업 시 각각 굽힘 안전율은 1.6587, 1.6651, 1.7824, 2.2198로 나타났으며 접촉 안전율은 1.0030, 1.0104, 1.0450, 1.1931로 나타났다. 주간거리에 따른 식부깊이의 굽힘 안전율과 접촉 안전율은 가장 차이가 큰 주간거리 80cm에서 식부깊이가 85, 105, 136mm일 때 작업 시 각각 굽힘 안전율은 2.8064, 2.5866, 2.2198로 나타났으며 접촉 안전율은 1.3275, 1.2507, 1.1931로 나타났다. 시뮬레이션 결과 정식기 베벨기어의 안전율은 주간거리가 짧을수록, 식부깊이가 깊을수록 더 낮게 나타났다. 그러므로 정식 작업 시 정식기의 부하와 내구성을 고려하여 적절한 작업조건을 선정해야 함을 알 수 있다. 또한 향후 다양한 토양 조건 및 작업 단수 등에 따른 포장시험을 추가로 진행하여 여러 조건에서의 안전율 시뮬레이션을 수행할 예정이다.

• The Journal of the Korea institute of electronic communication sciences
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• v.8 no.6
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• pp.881-889
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• 2013

In this paper, a nonlinear and adaptive back-stepping control technique is proposed for a speed control of IPMSM(Interior Permanent Magnet Synchronous Motor). The gain of back-stepping controller(including integral value of the states error) is designed for stability of the system. In order to adapting fast in variation of load torque, the controller is including load torque estimator. The simulation is completed by using PSIM software. The simulation results show that the designed back-stepping controller make the system stable in the constant torque region, and has better tracking performance than a controller without the integral gain.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.12
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• pp.3581-3586
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• 2009

This paper designed a robust control of an induction motor using a disturbance cancellation observer of a feedforward control. The speed response of conventional PI controller characteristic is affected by variations of load torque disturbance. In the proposed system, the speed control characteristic used a feedforward control which does not undergo the influence of the load torque disturbance. High speed calculation and processing for vector control is carried out by TMS320C31 digital signal processor. Validity of the proposed control method is verified through simulation and experimental result.