• 드라이브 ㆍ 컨트롤
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• 제15권2호
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• pp.9-21
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• 2018

The aim of this study was to develop and test a model of an auto-sensing hydraulic breaker that can automatically change its 4-step impact mode according to the rock strength using SimulationX. The auto-sensing hydraulic breaker with a 4-step variable impact mode has the advantage of obtaining optimal impact energy and impact frequency under various rock conditions compared to an auto-sensing hydraulic breaker with a 2-step variable impact mode, which has already been developed overseas. Several steps were necessary to conduct this study. First, the operation principle of the auto-sensing hydraulic breaker with the 2-step variable impact mode was analyzed. Based on the findings, an analysis model of the auto-sensing hydraulic breaker with the 4-step variable impact mode was developed (and compared with the 2-step variable impact mode) Finally, an analysis of the results established that the stepwise variable of the impact mode was implemented according to the rock strength and the difference of each impact mode was confirmed. This study is expected to contribute to the development of auto-sensing hydraulic breakers that are superior to those developed by advanced companies in foreign countries.

• 한국지역지리학회지
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• 제15권5호
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• pp.537-553
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• 2009

혁신도시 건설이 자립형 지방화를 통한 국가경쟁력 강화라는 방향성에서 지역전략산업 중심의 연계방안 마련이 핵심적 과제가 될 수 있다. 본 연구는 경북 혁신도시를 사례로 혁신도시와 연계한 경북의 지역전략산업 중심의 산학연계 구축방안 모색을 통하여 지역산업 육성전략을 제시하고자 한다. 이전공공기관과 지역산업간 연계분석과 지역전략산업 중심의 혁신도시 연계방안을 제시하였다. 연계방안에서는 경북의 전략 및 선도산업인 전자정보기기, 신소재부품, 생물한방 문화관광, 친환경에너지 등의 산업별 특성에 기반한 클러스터 구축방안을 제시하였다. IT BT산업과 같이 기술발전 속도가 빠른 산업분야의 경우 구미 혁신클러스터 추진단 및 경북지역 주요 혁신지원기관과 연계한 관련 주체간 지리적 인접을 통한 상호 연계협력이 필요하며, 자동차부품 기계 철강산업과 같은 성숙 기술분야는 기존 클러스터의 육성을 위한 교통 물류지원 등 인프라 강화가 핵심과제이다. 경제권의 광역화와 광역클러스터화에 따른 광역경제권 단위의 산업클러스터 육성도 새로운 과제이다.

• 한국재난정보학회 논문집
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• 제9권3호
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• pp.358-364
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• 2013

NDMS의 경우, 정보는 해당 지역 자원에 한정되어 관리되고 있으며, 타 기관 시스템과 연계되어 있지 않다. 그러므로 대규모 재난 발생 시, 여러 기관 사이에 분산된 필요한 자원을 찾기는 쉽지가 않다. 본 논문에서는 이러한 자원 관리 환경을 고려하여, 분산된 자원 관리시스템을 통합하는 모델을 개발하였다. 그것은 IDRM이라는 본 연구에서 제안하는 중앙 시스템을 중심으로 연계하는 새로 모델이다. 본 시스템은 한국도로공사, 전북도청, 그리고 대한건설기계협회의 테스트 사이트를 통하여 연계성이 검증될 것이다. 이러한 검증을 거쳐서, 본 시스템은 장래에 운영 가능한 실제 시스템으로 될 것으로 기대한다.

• 한국지능시스템학회논문지
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• 제22권6호
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• pp.675-680
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• 2012

전 세계적으로 풍력발전은 전력생산을 위해 사용되는 신재생 에너지원 중 가장 빨리 성장하고 있는 분야로 새로 건설되는 풍력발전단지는 전체 전력 생산량에서 많은 부분을 차지해가고 있다. 풍력발전단지의 설치 증가는 더욱 효율적인 운영과 유지보수에 대한 기술 개발을 요구하게 된다. CMS(Condition Monitoring System)는 풍력발전 시스템의 효율적 운영을 가능케 하는 중요한 도구로 운영자에게 기계의 운전 상태에 대한 정보를 제공함과 동시에 유지보수와 관련된 체계적인 정보를 제공한다. 이에 본 연구에서는 풍력발전기의 너셀에 부착된 가속도 센서로부터의 신호에 대한 FFT 분석을 통해 풍력발전기에서 발생될 수 있는 블레이드의 질량 불평형 및 공력 비대칭의 검출을 가능케 하는 진단기법을 제안하고자 하며 제안된 기법의 유용성 확인을 위해 3W급 소형 풍력발전기에의 적용을 통해 제안된 기법의 유용성을 확인하고자 한다.

• 드라이브 ㆍ 컨트롤
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• 제12권3호
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• pp.36-43
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• 2015

An autonomous vehicle control algorithm based on Ackerman Geometry is known to be reliable in low tire slip situation. However, vehicles at high speed make lateral errors due to high tire slip. In this paper, considering the tire slip of vehicles, the steering angle is determined based on the Ackerman Geometry and is supplemented tire slip angle by the Stanley steering algorithm. In addition, to prevent the tire slip, the algorithm, which restricts steering if a certain level of slip occurs, is used to reduce the lateral error. While many studies have been extended to include vehicle slip, studies also need to be carried out on the tire slip depending on hardware performance. The control algorithm of autonomous vehicles is compensated considering the sensor noise and the performance of steering actuator. Through the various simulations, it was found that the performance of steering actuator was the key factor affecting the performance of autonomous driving. Also, it was verified that the usefulness of steering algorithm considering the tire slip and performance of steering actuator.

• 드라이브 ㆍ 컨트롤
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• 제13권1호
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• pp.18-26
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• 2016

This research is conducted to develop an automatic steering system for parallel parking, and the performance of the system was evaluated by parallel parking a conventional vehicle. The automatic steering system consisted of MDPS (motor driven power steering) to control steering, ESC (electronic stability control) to acquire wheel speed, ultrasonic sensors to recognize the parking space, and a controller to communicate and handle data. The parallel parking process using the automatic steering control consisted of parking space recognition, parking path generation, and parking path tracking. The path for parallel parking was generated based on a kinematic model of a conventional vehicle, and a PI controller was used to control the steering angle for path tracking. Parallel parking using the automatic steering control was conducted according to vehicle speed conditions. The results show that the errors on the x-axis and y-axis were below 0.54 m and 0.14 m, respectively, and the error on the steering angle was less than $1^{\circ}$. Therefore, it is possible to implement parallel parking using an automatic steering control system for conventional vehicles.

• 드라이브 ㆍ 컨트롤
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• 제13권2호
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• pp.19-25
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• 2016

Recently, drivers have begun to regard comfort in the cabin as one of the most important factors in construction equipment like forklifts. Accordingly, it has become more important to design a forklift cabin with a better sound quality as well as lower sound level, which can make a driver more comfortable. In this paper, the correlation between subjective evaluation and Zwicker's sound quality index was analyzed through a blind test by a few workers in forklifts and other construction equipment in several countries. Correlation analysis showed that Loudness and Sharpness were ranked in sequence, and tendencies were different from country to country. Also, contribution analysis for Loudness and Sharpness using operational transfer path analysis (OTPA), which is widely used in the field of noise, vibration, and harshness (NVH), was performed. However, Loudness and Sharpness cannot be used with OTPA directly because there are no linear relationships between the sources and receivers. In this paper, both are calculated by applying the DIN 45631 method with a contribution rate (%) of 1/3 Octave Sound Pressure Level by OTPA method in addition to considering spectral masking.

• 드라이브 ㆍ 컨트롤
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• 제12권3호
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• pp.52-59
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• 2015

An electro hydraulic poppet valve (EHPV) and a variable orifice poppet are assembled in a single block, which is referred to as a RHINO but is also generally called a pilot-operated flow control valve. In this study, we analyzed the structure and the operating principle for a RHINO applied in a 21-ton electric excavator system. The RHINO was experimentally tested to measure the dynamic responses and the pressure energy loss. In this test, we investigated the variation in the conductance coefficient according to the increase in the supply pressure under a constant current and a variation in the flow rate according to the increase in the current. Then, the geometrical shapes and the spring stiffness of the RHINO were considered to develop an analysis model. The characteristics (current-force and hysteresis) for the solenoid based on the experimental data were reflected in the analysis model that was developed, and the reliability of the analysis model was also verified by comparing the experimental and analytical results. The developed model is thus considered to be reliable for use in a wide range of applications, including optimum design, sensitivity analysis, parameter tuning, etc.

• 드라이브 ㆍ 컨트롤
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• 제13권1호
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• pp.1-9
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• 2016

Nowadays automatic transmission equipped vehicles prevail in construction and agricultural equipment due to their convenience in driving and operation. Though domestic vehicle manufacturers install imported electronic controlled transmissions at present, overseas products will be replaced by domestic ones in the near future owing to development efforts over the past 10 years. For passenger cars, there are many kinds of shift control algorithms that enhance the shift quality such as feedback and learning control. However, since shift control technologies for heavy duty vehicles are not highly developed, it is possible to improve the shift quality with an organized control method. A feedback control algorithm for neutral-into-gear shift, which is enabled during the inertia phase for the master clutch slip speed to track the slip speed reference, is proposed based on the power transmission structure of TH100. The performance of the feedback shift control is verified by a vehicle test which is implemented with firmware embedded TCU. As the master clutch engages along the predetermined speed trajectory, it can be concluded that the shift quality can be managed by a shift time control parameter. By extending the proposed feedback algorithm for neutral-into-gear shift to gear change and shuttle shift, it is expected that the quality of the shift can be improved.

• 드라이브 ㆍ 컨트롤
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• 제12권3호
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• pp.18-24
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• 2015

The plug-in hybrid electric vehicle has a high fuel economy and can be driven long distances. Its different modes include the electric vehicle, hybrid electric vehicle, and only engine operating mode. A power management strategy is important to determine which mode should be selected. The strategy makes the vehicle more efficient using appropriate power sources for driving. However, the strategy usually needs a driving speed profile which is future driving cycle. If the profile is known, the strategy easily determines which mode is driven efficiently. However, it is difficult to estimate the speed profile for a real system. To address this problem, this paper proposes a new power distribution strategy using a neural network. The average speed and driving range are used as input parameters to train the neural network system. The strategy determines a limit for the use of the battery and the desired power is distributed between the engine and the motor simultaneously. Its fuel economy can increase by improving the basic strategy.