• 제어로봇시스템학회논문지
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• 제20권1호
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• pp.48-57
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• 2014

It is suggested that the curvature trajectory be used to estimate the real-time moving sound sources and efficiently the robot estimating the sound sources. Since the target points of the real-time moving sound sources change, the mobile robot continuously estimates the changed target points. In such a case, the robot experiences a slip phenomenon due to the abnormal velocity and the changes of the navigating state. By selecting an appropriate curvature and navigating the robot gradually by using it, it is possible to enable the robot to reach the target points without having much trouble. In order to recognize the sound sources in real time, three microphones need to be organized in a straight form. Also, by applying the cross-correlation algorithm to the TDOA base, the signals can be analyzed. By using the analyzed data, the locations of the sound sources can be recognized. Based on such findings, the sound sources can be estimated. Even if the mobile robot is navigated by selecting the gradual curvature based on the changed target points, there could be errors caused by the inertia and the centrifugal force related to the velocity. As a result, it is possible to control the velocity of both wheels of the robot through the velocity PID controller in order to compensate for the slip phenomenon and minimize the estimated errors. In order to examine whether the suggested curvature trajectory is appropriate for estimating the sound sources, two mobile robots are arranged to carry out an actual experiment. The first robot is moved by discharging the sound sources, while the second robot recognizes and estimates the locations of the discharged sound sources in real time.

• 대한기계학회논문집A
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• 제20권1호
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• pp.146-153
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• 1996

A SCARA type direct drive robot which can be used in the assembly operation was designed and manufactured. Graphite fiber epoxy composite material was used in the fabrication of the robot arm structure in order to improve the speed of the robot arm with a high damping effect. For model-based control and sensitivity analysis of system parameters, the dynamic model of robot arm and drive servo amplifier parameters such as equivalent gains of PWM driver and velocity gains of servo system were estimated from frequency response tests. The complete dynamic model for overall robot system was used in the simulation of the open-loop control. The simulation results agreed reasonably well to the experimental results. The feedforward control using the dynamic models improved the trajectory tracking performance, decreasing the tracking error by factor of three compared with PID control. This study found that the inverse dynamic model of the robot arm including the drive servo system showed better performances than the case of arm dynamic model only.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2006년도 춘계학술대회 논문집
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• pp.289-290
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• 2006

In general, atomic force microscope (AFM) used for metrological purpose has measuring range less than a few hundred micrometers. We design and fabricate an AFM with long measuring range of $200mm{\times}200mm$ in X and Y axes. The whole stage system is composed of surface plate, global stage, microstage. By combining global stage and microstage, the fine and long movement can be provided. We measure the position of the stage and angular motions of the stage by laser interferometer. A piezoresistive type cantilever is used for compact and long term stability and a flexure structure with PZT and capacitive sensor is used for Z axis feedback control. Since the system is composed of various actuators and sensors, a real time control program is required for the implementation of AFM. Therefore, in this work, we designed a multi-axis control program using a FPGA module, which has various functions such as interferometer signal converting, PID control and data acquisition with triggering. The control program achieves a loop rate more than 500 kHz and will be applied for the measurement of grating pitch and step height.

• 한국정보통신학회논문지
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• 제20권11호
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• pp.2162-2166
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• 2016

본 논문은 해저탐사에서 소나영상 촬영을 위한 무인자율항법(AUSV)시스템 구현에 관한 연구이다. 자율항법 시스템은 선체에 모션센서, DGPS에 의한 현재 경위도 좌표와 목표지 경위도 좌표의 차를 가지고 선체 추진체의 항로를 FFPID 알고리즘으로 제어한다. 실험결과, 목적지 좌표에 대한 제어좌표 오차는 전체 항법거리 1km 에서 6 m 이하로 우수하다. 또한 자율항법 모드에서의 소나영상 촬영 결과물은 유인선 촬영 결과물과의 차이는 12 화소 이하로 전체 영상 차이는 거의 식별할 수 없이 동일하다. 개발된 시스템은 유인선으로 촬영 불가능한 해저 지형에 대한 소나영상 촬영을 위한 새로운 방법으로 활용 가능하다.

• 한국산학기술학회논문지
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• 제12권2호
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• pp.821-828
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• 2011

본 논문은 자동항로 추적(Track keeping control), 자동조타(Automatic steering), 자동 접이안(Automatic mooring control) 등으로 구성된 자동운항 시스템 중 자동조타장치의 성능 개선 알고리즘 개발에 대해 다루고 있다. 자동조타는 풍력 또는 조력 등의 영향으로부터 선박의 설정 항로와 실제 침로와의 차이를 계산하여 설정된 항로를 유지하며 항해하므로, 조타에 소요되는 선원의 지속적인 항해로 인한 운전 부담을 경감시키고 불필요한 타조작에 의한 항로 이탈을 줄임으로써 항해거리 단축과 연료비용을 절약할 수 있는 시스템이다. 선박의 모델링을 위하여 Nomoto 모델에 근거하여 전달함수를 구하고, 조종성능(Manoeuvirng) 편리성을 고려하여 타각 입력에 대한 선수각 응답으로 표시된 선박의 4자유도만을 고려한 선형 모델을 제안하고 선박 자동조타장치의 최대각과 타각율을 고려하여 Fuzzy제어기를 설계 하였고 PID제어기로 성능을 비교 분석하였다.

• 한국식품과학회지
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• 제49권2호
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• pp.162-167
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• 2017

훈연 가쓰오부시의 벤조피렌 저감화를 위하여 훈연기를 개선하고 이의 저감화 효과를 평가하였다. 기존 훈연기는 동일한 히터를 사용하여 연기생성 및 가열을 동시에 행하는데 비하여 개선된 훈연기는 연기생성부 및 가열부를 갖추어 연기생성과 가열이 각각 되도록 하였다. 연기생성부는 훈연실 내부에 설치된 CdS 광센서, on/off 제어기, 연소실과 훈연실 사이에 연기 공급을 개폐하는 압축구동 회전체로 구성하였다. 가열부는 훈연실 내부의 온도센서, PID 제어기, 전기히터로 구성하였다. 자숙된 가다랑어를 연기농도를 세가지 수준으로 제어하며 45도에서 훈연한 결과 108시간 경과 후 연기농도가 낮은 순으로 벤조피렌 농도가 5.87, 7.83, $11.41{\mu}g/kg$로 각각 나타났다. 연기농도를 가장 낮은 농도에서 온도를 달리하여 훈연한 결과 벤조피렌 농도가 각각 5.87, 4.82, $3.27{\mu}g/kg$로 검출되었다. 따라서 벤조피렌 저감화 조건은 낮은 연기농도와 높은 온도가 바람직함을 알 수 있었다. 기존 훈연기는 높은 온도를 사용할 경우 연기농도가 종속적으로 높아지기 때문에 저감화 조건을 만족시킬 수 없는 반면에 본 개선된 훈연기는 저감화를 구현할 수 있었다.

• Journal of Biosystems Engineering
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• 제34권5호
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• pp.315-324
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• 2009

Various types of vibration are transmitted to operators of agricultural tractors while working in the field. Most harmful vibration to human body is ride vibrations with low frequency ranging from 1 to 10 Hz, caused by rough terrain. These ride vibration has vertical and rotational components. This study was conducted to develop an active seat suspension system with two degrees of freedoms, enabling effectively reduce vibrations in vertical and pitch motions. Therefore, a mechanism for the active seat suspension was developed, and an electro-hydraulic servo system and a controller to drive the active seat suspension system were also developed in this study. A simulation model was developed to evaluate how the active seat suspension system effectively reduce the vibrations transmitted to the base of seat. Active seat suspension was optimized to enhance the performance using the developed simulation model. The performance of the seat suspension system was evaluated according to the test codes described in EEC78/764 in order to investigate the feasibility of application to agricultural tractors. The result showed that the developed active seat suspension system could reduce the magnitude of vertical vibration up to 80% for the input vibrations according to the test codes described in EEC78/764. The system could reduce the rotational displacement of ${\pm}\;2.5$ degrees up to 50% for the pitch vibration on the average in the frequency range of 1 to 2 Hz.

• 한국산업융합학회 논문집
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• 제20권1호
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• pp.34-48
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• 2017

This study proposes a new approach to control a trajectory control of vertical type articulated robot arm with six revolution joints by computed torque method for manufacturing process automation. The proposed control scheme takes advantage of the properties of the fuzzy controllers. The proposed method is suitable to control of the trajectory and path control in cartesian space for vertical type articulated robot manipulator for forging manufacturing process automation. The results is illustrated that the proposed fuzzy computed torque controller is more stable and robust than the conventional computed torque controller. This study is included with an analytical methodology of inverse kinematic computation for 6 DOF manipulators. And an intelligent PID based on feed forward fuzzy control structure is applied to control the working path control with disturbances caused by uncertainty parameters of the manipulator dynamic model. Lastly, the validity of proposed is verified by simulations and experiments.

• 한국컴퓨터정보학회논문지
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• 제19권12호
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• pp.187-196
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• 2014

본 논문에서는 고정된 역간 거리를 정해진 운전 시분내에 주행에너지를 최소화하며 주행하는 열차의 특성을 파악하고 수학적으로 모델링한다. 도시철도차량 자동주행에 일반적으로 사용되는 PID제어기 대신 목표값에 추종하면서도 자동 주행 중 소비에너지가 최소화되도록 최적제어기를 사용하여 철도 차량를 모델링하였으며 실제 동일한 운행조건하에서 설계한다. 실제 선로 조건을 적용하여 별도의 차상장치나 선로주변시설 없이도 자동운전 중 주행에너지를 최소하여 주행에너지를 절감하고자 한다. 따라서 8호선 실 노선 구간별 운전시분 내에서 실측 데이터 분석을 위해 직선구간/구배구간/곡선구간 등 구간을 선정하고 그 구간에서 열차의 운행패턴에 따라 에너지를 절감하는 열차운행을 방법을 제시하였다.

• Journal of Advanced Marine Engineering and Technology
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• 제19권1호
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• pp.60-70
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• 1995

In the field of marine transportation the energy saving is one of the most important factors for profit. In order to reduce the fuel oil consumption the ship's propulsion efficiency must be increased as much as possible. The propulsion efficiency depends upon a combination of an engine and a propeller. The propeller has better efficiency as lower rotational speed. This situation led the engine manufacturers to design the engine that has lower speed, longer stroke and a small number of cylinders. Consequently the variation of rotational torque became larger than before because of the longer delay-time in the fuel oil injection process and an increased output per cylinder. As this new trends the conventional mechanical-hydrualic governors for engine speed control have been replaced by digital speed controllers which adopted the PID control or the optimal control algorithm. But these control algorithms have not enough robustness to suppress the variation of the delay-time and the parameter pertubation. In this paper we consider the delay-time and the perturbation of engine parameters as the modeling uncetainties. Next we design the controller which has zero offset in steady state engine speed, based on the two-degree-of-freedom control theory and $\mu$-synthesis. Thd validity of the controller is investigated through the response simulation. We use a personal computer and an analog computer as the digital controller and the engine (plant) part respectively. And, we certify that the designed controller maintains its performance even though the engine parameters may vary.