• 한국정밀공학회지
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• 제28권3호
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• pp.292-300
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• 2011

Control systems in machinery equipment provide correction signals to motion units in order to reduce or cancel out the mismatches between sensor feedback signals and command or desired values. In this paper, we introduce a simulator for control characteristics of machinery equipment. The purpose of the simulator development is to provide mechanical system designers with the ability to estimate how much dynamic performance can be achieved from their design parameters and selected devices at the designing phase. The simulator has a database for commercial parts, so that the designers can choose appropriate components for servo controllers, motors, motor drives, and guide ways, etc. and then tune governing parameters such as controller gains and friction coefficients. The simulator simulates the closed-loop control system which is built and parameter-tuned by the designer and shows dynamic responses of the control system. The simulator treats the moving table as a 6 degrees-of-freedom rigid body and considers the motion guide blocks stiffness, damping and their locations as well as sensor locations. The simulator has been under development for one and a half years and has a few years to go before the public release. The primary achievements and features will be presented in this paper.

• 제어로봇시스템학회논문지
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• 제8권6호
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• pp.445-454
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• 2002

Torque ripple control of brushless DC motors has been the persisting issue of the servo drive systems in which the speed fluctuation, vibration and acoustic noise should be minimized. In this paper, a novel approach to achieve the ripple-free torque control with maximum efficiency based on the d-q reference frame is presented and analyzed. The proposed approach can provide the optimized phase current waveforms over wide speed range incorporating cogging torque compensation without an access to the neutral point of the motor windings. Moreover, the undesirable errors caused by the assumptions such as 3 phase balance or symmetry of the phase back EMF between electrical cycles, which are related with the manufacturing imperfections, can be also eliminated. As a result, the proposed approach provides a simple and clear way to obtain the optimal motor excitation currents. A hysteresis current control system is employed to produce high-frequency electromagnetic torque ripples for compensation. The validity and applicability of the proposed control scheme to real situations are verified through the simulations and experimental results.

• Journal of Advanced Marine Engineering and Technology
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• 제33권8호
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• pp.1212-1219
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• 2009

본 연구에서는 실용설계의 새로운 도구로써 제어계의 강인성, 성능, 안정성 등의 설계지침을 정량화하기 쉽고 해가 효율적으로 구해져 주목받는 선형행렬부등식을 이용하여 강인한 LMI 제어기를 설계한다. 우선 다층상 구조물의 진동제어를 위해 수학적 모델링을 행하고 적분형 서보계를 적용한 LMI 제어 기법으로 상태 피드백 제어칙을 설계한다. 다음으로 설계한 제어칙으로 시스템 불확실성의 변동에 대해 시간영역의 설계사양을 고려한 경우와 고려하지 않은 경우에 대하여 시뮬레이션을 행하고 실제 적용 가능성을 검토한다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 추계학술대회
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• pp.951-955
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• 2004

Piezoelectric(PZT) actuator can substitute for solenoid which is used in fluid control field because it has faster response times and no possibility of explosion. Besides, it is available in a high temperature and it has low energy consumption. In this study, pneumatic micro valve, bimorph type PZT actuator using the softner type PZT, carbon plate as a shim and its controller circuit were suggested and investigated. Performance tests and characteristics analysis, such as displacement, force, hysteresis and frequency properties, were carried out. The displacement of the actuator measured at the end point was 63 ${\mu}m$., force of the actuator was 0.052 N and maximum operating frequency was 15Hz. Also, characteristics of the micro valve with PZT actuator were evaluated in a testing system. The results show that the suggested PZT actuator is suitable for micro valve.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2002년도 ICCAS
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• pp.100.1-100
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• 2002

In this paper, we present autonomous mobile robot system, which has an image recognition module and perform tasks by itself with manipulator. Autonomous mobile robot can push each individual button on an elevator panel from a person's command. After the robot receives its command, it analyzes the image information of the elevator button that is acquired by CCD camera in an indoor environment with an elevator. In order to recognize the numbers on the button, the robot separates the number area in button and recognizes the segment through a neural network algorithm. We use the bar code form on the manipulator to find the position of the end of manipulator. The validity of the proposed method i...

• 제어로봇시스템학회논문지
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• 제12권5호
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• pp.505-508
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• 2006

This paper presents a new analytical approach for designing multiloop PI controllers for disturbance rejection in multivariable processes with time delay. The proposed method is based on IMC-PID design approach. To overcome a sluggish load response by dominant pole in the process, the IMC filter is modified to compensate the dominant pole effect. Based on the modified IMC filter, an analytical tuning rule for multiloop PI controller is driven by extending the generalized IMC-PID method for single input/single output (SISO) systems [1] to multi input/multi output (MIMO) systems. Simulation results show that the proposed method gives a satisfactory load performance as well as servo performance in the multiloop system.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2001년도 전력전자학술대회 논문집
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• pp.25-29
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• 2001

The BLDCM (Brushless DC Motor) characterized by linear torque to current, and speed to voltage has low acoustic noise, and fast dynamic response. Moreover, it has high power density with high proportion of torque to inertia in spite of small size drive. But, it produce torque ripple due to the motor inductance components in stator windings and back-EMF, when armature current is commutated. Therefore, it is difficult to apply the BLDCM to a precision servo drive system. In this paper is proposed to a new current control algorithm with using fourier series coefficients can minimize torque ripple due to the phase current commutation of BLDCM. Simulation and Experimental results prove the effectiveness the proposed algorithm through comparison with the conventional used unipolar PWM method.

• 대한기계학회논문집B
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• 제37권3호
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• pp.213-219
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• 2013

본 논문의 목적은 스풀 랜드(spool land)와 슬리브(sleeve) 사이의 정특성 방정식으로부터 스풀 밸브의 압력 특성과 유동특성을 구하는 것이다. 이러한 목적을 달성하기 위하여, 스풀 랜드와 슬리브 사이의 유동을 환상간극 유동과 오리피스 유동, 그 중간의 천이 영역으로 나누고, 천이 영역의 유량계수를 길이에 따른 두 영역으로 나눈 선형 일차방정식으로 가정하였다. 스풀 밸브의 압력특성방정식을 구하기 위해 스풀의 중립지점에서부터의 변위에 따른 유동을 $q_a=q_b=0$의 조건으로부터 구하였으며, 스풀 밸브의 유량특성방정식을 구하기 위하여 스풀의 중립지점에서부터의 변위에 따른 유동을 $q_a=q_b$, $p_a=p_b$의 조건으로부터 구하였다. 구해진 수식의 타당성은 수치해석을 통해 실험식 및 기존논문과의 비교를 통해 확인하였다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.43-43
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• 2000

In this paper, we introduce a case study of developing a miniature humanoid robot that has 16 degrees of freedom and is able to perform statically stable walking. The developed humanoid robot is 37cm tall and weighs 1,200g. RC servo motors are used as actuators. The robot can walk forward and turn to any direction on even surface. It equipped with a small digital camera, so it can transmit vision data to a remote host computer via wireless modem. The robot can be operated in two modes; One is a remote-controlled mode, in which the robot behaves according to the command given by a human operator through the user-interface program running on a remote host computer, the other is a stand-alone mode, in which the robot behaves autonomously according to the pre-programmed strategy. The user-interface program also contains a robot graphic simulator that is used to produce and verify the robot's gait motion. In our walking algorithm, the ankle joint is mainly used lot balancing the robot. The experimental results shows that the developed robot can perform statically stable walking on even surface.

• Journal of the Optical Society of Korea
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• 제9권2호
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• pp.49-53
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• 2005

We report a new configuration of a reflection-type confocal scanning optical microscope system for measuring the refractive index profile of an optical waveguide. Several improvements on the earlier design are proposed; a light emitting diode (LED) at 650 nm wavelength instead of a laser diode (LD) or He-Ne laser is used as a light source for better index precision, and a simple longitudinal linear scanning and curve fitting techniques are adapted instead of a servo control for maintaining an optical confocal arrangement. We have obtained spatial resolution of 700 nm and an index precision of $2\times10^{-4}$. To verify the system's capability, the refractive index profiles of a conventional multimode fiber and a home-made four-mode fiber were examined with our proposed measurement method.