• 한국생물환경조절학회:학술대회논문집
• /
• 한국생물환경조절학회 2003년도 춘계 학술대회 논문집
• /
• pp.64-69
• /
• 2003

노동 집약적이던 농업은 급속한 기계화로 인하여 노동력의 절감은 여러 분야에서 활성화되고 있지만, 농업은 수익성이 높지 않아 여전히 사람들이 노동을 기피하는 산업중의 하나이다. 온실 자동화는 특용 작물 등의 고부가가치 상품에만 한정되어 있으므로 이를 개선해야 한다. (중략)

• 한국생물환경조절학회:학술대회논문집
• /
• 한국생물환경조절학회 2003년도 춘계 학술대회 논문집
• /
• pp.181-190
• /
• 2003

컴퓨터 시각장치에 의한 3차원 정보를 이용한 연구현황으로서는 최근에 많이 연구되어지고 있으며, 그 중에서 가장 일반적인 방법으로 사람의 눈과 비슷한 구조를 가진 스테레오 시각을 이용한다. 한 대의 카메라를 통해 얻어지는 3차원 형상 정보는 3차원 대상체가 2차원 평면상에 투사되어 얻어진 정보이므로 대상체가 갖는 3차원 공간 정보를 얻기 위한 접근법이 필요하다. (중략)

• 한국의학물리학회:학술대회논문집
• /
• 한국의학물리학회 2006년도 제33회 추계학술대회 발표논문집
• /
• pp.25-25
• /
• 2006

• Journal of Biosystems Engineering
• /
• 제35권4호
• /
• pp.257-261
• /
• 2010

Surface energy is the principal factor of anti-condensation. High surface energy appears hydrophilic itself and low surface energy represents hydrophobic itself. The contact angle is widely being used for measurement of surface energy of materials, evaluation of coating performances, measurement of wettability, and so on. However, the existing contact angle measuring system is so expensive for purchasing and complicated, so it takes a lot of time and money to use. This study was conducted to develop the algorithm for evaluating hydrophilic performance through measuring the contact angle of water droplet automatically, and fabricate relatively simple measuring system using a low-cost monochrome camera and image processing. A constant amount of water was firstly allocated on a slide by a micropipette, and then the image of water droplet was captured by monochrome digital camera and sent to a computer. The image was binarized and then reduced noises by labeling. Finally, the contact angle of water droplet was computed by using three points (left, right, and top coordinates), simple linear mathematics, and trigonometric function. The experimental results demonstrated the accuracy and reproducibility of the developed system showing less deviations and deviation ratio.

• Structural Engineering and Mechanics
• /
• 제88권4호
• /
• pp.389-403
• /
• 2023

In order to explore the influence of tooth root cracks on the dynamic characteristics of multi-stage planetary gear transmission systems, a concentrated parameter method was used to construct a nonlinear dynamic model of the system with 30-DOF in bending and torsion, taking into account factors such as crack depth, length, angle, error, time-varying meshing stiffness (TVMS), and damping. In the model, the energy method was used to establish a TVMS model with cracks, and the influence of cracks on the TVMS of the system was studied. By using the Runge- Kutta method to calculate the differential equations of system dynamics, a series of system vibration diagrams containing cracks were obtained, and the influence of different crack parameters on the vibration of the system was analyzed. And vibration testing experiments were conducted on the system with planetary gear cracks. The results show that when the gear contains cracks, the TVMS of the system will decrease, and as the cracks intensify, the TVMS will decrease. When cracks appear on the II-stage planetary gear, the system will experience impact effects with intervals of rotation cycles of the II-stage planetary gear. There will be obvious sidebands near the meshing frequency doubling, and the vibration trajectory of the gear will also become disordered. These situations will become more and more obvious as the degree of cracks intensifies. Through experiments, the theoretical results are in good agreement with experimental results, verifying the correctness of the theoretical model. This provides a theoretical basis for fault diagnosis and reliability research of the system.

• Journal of Mechanical Science and Technology
• /
• 제16권7호
• /
• pp.942-949
• /
• 2002

The use of a combined starter/generator integrated into the drive train of an automobile offers several possibilities for improvement of fuel economy The use of such a starter/generator system is made feasible by a switch from a 14 volts electrical system to a 42 volts system, however, the sizing of the components is not a trivial problem. This study combines a dynamic electromechanical model of the starter, battery and power electronics with the nonlinear mechanics of the piston/crankshaft system and a thermofluid model of the compression and expansion processes to investigate the cold start problem. The example involves the start of an eight cylinder engine at -25 degrees Celsius. This paper shows how the mechatronic V8 engine of an automotive starter/generator system for the startability works well.

• Journal of Power Electronics
• /
• 제15권6호
• /
• pp.1547-1558
• /
• 2015

A predictive functional control (PFC) scheme for permanent magnet synchronous motor (PMSM) servo systems is proposed in this paper. The PFC-based method is first introduced in the control design of speed loop. Since the accuracy of the PFC model is influenced by external disturbances and speed detection quantization errors of the low distinguishability optical encoder in servo systems, it is noted that the standard PFC method does not achieve satisfactory results in the presence of strong disturbances. This paper adopted the Kalman filter to observe the load torque, the rotor position and the rotor angular velocity under the condition of a limited precision encoder. The observations are then fed back into PFC model to rebuild it when considering the influence of perturbation. Therefore, an improved PFC method, called the PFC+Kalman filter method, is presented, and a high performance PMSM servo system was achieved. The validity of the proposed controller was tested via experiments. Excellent results were obtained with respect to the speed trajectory tracking, stability, and disturbance rejection.

• Structural Engineering and Mechanics
• /
• 제17권6호
• /
• pp.819-828
• /
• 2004

A new process for estimating the natural frequency and the corresponding damping ratio in large structures is discussed. In a practical situation, it is very difficult to analyze large structures precisely because they are too complex to model using the finite element method and too heavy to excite using the exciting force method; in particular, the measured signals are seriously influenced by ambient noise. In order to identify the structural impulse response associated with the information of natural frequency and the corresponding damping ratio in large structures, the analysis process, a so-called "multiresolution blind system identification algorithm" which combines Mallat algorithm and the bicepstrum method. High time-frequency concentration is attained and the phase information is kept. The experimental result has demonstrated that the new analysis process exploiting the natural frequency and the corresponding damping ratio of structural response are useful tools in structural analysis application.

• 생물환경조절학회지
• /
• 제22권4호
• /
• pp.303-308
• /
• 2013

배나무 방제용 무인살포시스템 개발을 위하여 생력화를 위한 작업기기를 설계하였다. 또한, 노즐의 분무유형을 실험적으로 분석하여 적정 살포를 위한 노즐 각도, 노즐과의 거리, 수평방향 살포시 거리를 선정하였다. 본 연구를 수행하기 위하여 배의 과수 형태와 재배 환경을 사전 조사하였다. 살포시스템의 살포진행방향에 적합한 분사 노즐각도를 선정하였다. 배나무와 살포시스템 간의 수직거리에 따라 달라지는 살포 정도를 비교하기 위하여 노즐과의 높이에 따른 분포도를 측정하였다. 배나무와 살포 시스템과의 적정 측면 거리를 선정하기 위하여 측면 살포시 거리에 따라 달라지는 분무량을 측정하였다. 무인살포시스템의 약대는 배의 식재 간격에 적합하도록 좌우가 동일한 형태로 2.5m까지 펼쳐지도록 설계 및 제작 하였다. 또한 일정하지 않은 배나무의 높이에 따라 약대의 높이가 1.7m까지 조절되도록 하였다. 본 시스템에 적합한 노즐 각도는 $15^{\circ}$로 나타났다. 배나무와 살포시스템과의 수직거리는 0.7m에서 0.9m의 간격을 유지하여 약제를 살포해야 된다는 것을 알 수 있었다. 수평방향으로 살포하는 경우 좌우 -0.9m에서 0.9m까지의 분무량이 가장 많았다. 약대와의 거리가 0.9m에서 2.1m일 때 가장 많은 분무량을 나타냈다. 실험을 통하여 배 과수원에서의 무인살포시스템에 맞는 분무 환경을 확인 할 수 있었다. 배 과수와의 거리에 따라 적정 거리를 유지하는 시스템을 개발함으로써 효율적인 약액 살포가 가능하게 하였다. 하지만 본 연구에서 진행된 실험은 제한된 실내 환경에서 진행된 것이기 때문에 제작된 시스템의 실제 과수원 환경에서의 실험이 필요하다.

• 한국생물환경조절학회:학술대회논문집
• /
• 한국생물환경조절학회 1998년도 임시총회 및 학술논문발표요지
• /
• pp.36-40
• /
• 1998

대부분의 과채류가 그러하듯이 신선도는 상품가치 판단기준의 가장 중요한 척도중에 하나이다. 현장에서 생산된 상태로 소비자에게 가장 빠른 유통경로를 통해서 공급되는 것이 가장 바람직하지만, 때로는 그렇지 못하는 경우도 생긴다. 따라서 가능하면 수확, 운반, 저장시에 신선도를 오래 유지할 수 있도록 만드는 것이 여러 가지 측면에서 유리하다. (중략)