http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
개별검색 DB통합검색이 안되는 DB는 DB아이콘을 클릭하여 이용하실 수 있습니다.
통계정보 및 조사
예술 / 패션
<해외전자자료 이용권한 안내>
- 이용 대상 : RISS의 모든 해외전자자료는 교수, 강사, 대학(원)생, 연구원, 대학직원에 한하여(로그인 필수) 이용 가능
- 구독대학 소속 이용자: RISS 해외전자자료 통합검색 및 등록된 대학IP 대역 내에서 24시간 무료 이용
- 미구독대학 소속 이용자: RISS 해외전자자료 통합검색을 통한 오후 4시~익일 오전 9시 무료 이용
※ 단, EBSCO ASC/BSC(오후 5시~익일 오전 9시 무료 이용)
본 논문에서는 전기유동유체와 압전필름 액튜에이터를 특징으로 하는 하이브리드형 스마트 구조물에 대한 능동 진동제어를 실시하였다. 먼저, 가운데가 빈 샌드위치형태의 복합재료 구조물속에 전기유동유체를 삽입하고 또한 구조물 표면에는 압전필름을 접착하여 스마트 구조물을 제작하였다. 그리고, 전기유동유체에 대해서는 전기장함수의 주파수응답을 특징으로 하는 제어알고리즘을, 압전필름에 대해서는 신경회로망 제어기를 도출하였다. 이 두가지 액튜에이터를 개별적으로 적용하였을 때와, 동시에 적용하였을 때의 능동 진동제어 성능을 과도진동과 강제진동 하에서 고찰하여, 제시된 능동 진동제어 방법론의 타당성을 입증하였다. This paper provides a proof-of-concept investigation on an active vibration control of a hybrid smart structure (HSS) consisting of an electrorheological fluid actuator (ERFA) and a piezoelectric film actuator (PFA). Firstly, an HSS beam is constructed by inserting a starch-based electrorheological fluid into a hollow composite beam and bonding piezoelectric films on the surfaces of the structure, respectively. The control scheme for the ERFA is developed as a function of excitation frequencies on the basis of field-dependent frequency responses On the other hand, as for the PFA, a neuro-sliding mode controller (NSC) incorporating neural networks with the concept of sliding mode control is formulated. An experimental implementation for both the ERFA and the PFA is forced vibrations. Both the increment of damping ratios and the suppression of tip deflections are evaluated in order to demonstrate the control effectiveness of the ERFA, the PFA, and the hybrid actuation methodology. The experimental results exhibit a superior ability of the hybrid actuation system to tailor elastodynamic responses of the HSS rather than a single class of actuation system alone.
본 논문은 압전세라믹 액튜에이터를 이용한 유연 그리퍼의 힘 추적제어에 관한 것이다. 먼저, 해밀돈 법칙을 이용하여 제안된 그리퍼 시스템의 운동지배 방정식을 유도한 후, 모달해석을 통해 주파수 변동의 불확실 인자가 포함된 상태공간 제어모델식을 도출하였다. 제어기로서는 시스템 불확실성에 강건한 슬라이딩 모드 제어기를 도입하였고, 완전차수 관측시를 이용하여 선단의 힘 센서 신호를 통해 시스템의 상태변수들을 추정하였다. 실험적 구현과 시뮬레이션을 통해 정현파와 계단파의 요구함에 대한 유연 그리퍼 선단에서의 힘 추적제어를 실시하여 바람직한 추적성능을 얻었다. 연구결과를 통해, 향후 본 논문에서 제시된 함추적 방법론을 로봇의 소형 그리퍼에 효과적으로 적용할 수 있음을 입증하였다. This paper provides a robust tracking control on tip force of a flexible gripper via piezoceramic actuator. Firstly, a dynamic governing equation for the proposed gripper is derived by employing Hamilton`s principle. A control model including uncertain system parameters such s natural frequency variations is then obtained via modal analysis. In addition, a sliding mode controller inherently robust to system uncertainties is adopted to carry out a tracking control for tip forces of the gripper. With the aid of sensor output information on tip forces, a full-order observer is formulated to estimate state variable of the gripper system. Finally, both simulation and experimental implementation are undertaken to evaluate tracking performances for desired force trajectories such as sinusoidal and step functions. The results explicitly exhibit that the proposed methodology is very effective in the robot gripper.
In this paper, author investigated which process is better than Shot Blasting and pickling for cleaning of hot roll steel products. To induce the results, author first compared with the pickling process and the Shot blasting process theoritically. and than investigated the speciality and productivity of each process. The results are as follows: 1. The Blasting method is more economic and productive than the pickling method. 2. But, blasting method couldn't cover the all area of hot roll steel cleaning. For Example, Blasting method couldn't get the surface texture that is better than Ra 20μ. 3. For the efficient cleaning, It brings good result to use combining the pickling and the blasting method.
In metal cutting. the cutting force consist of static and dynamic components. In earlier works of metal cutting. however, a little attention has been paid to the dynamic component in steady cutting condition. To understand to behavior of the dynamic component in more detail in this study, the static and dynamic components of cutting force in face milling were measured by a dynamometer and the frequency components of cutting forces were also analyzed by stress frequency analyzer. Form measured results, the effects of cutting conditions and the dynamic components of cutting forces were investigated. when facing the workpieces made of steel. As a results, the following conclusions can be obtained. 1. The static and dynamic component of cutting force is propotional to the exponent of cutting volume. 2. The increasing of depth of cut is directly propotional to static component of cutting force. but the dynamic component of cutting force is stabilized by increasing of depth of cut 3. Dynamic component is the maximum at 100m/min. of cutting speed because SM15C material is developed build-up edge in that cutting speed.
In the industries, we usually use a shot blasting process for the cleaning of steel plates. During the shot blasting, the steel plate surface would be work harden. These phenomena may be cause the crack as the bending of these plate. In this theses, author investigated the effect of shot blasting and specimen size on cold bending of plates by experiments. After Appling the shot blasting, the residual stresses occurred on the surface of the steel plate thereby the Surface hardness would be increased. Experiment results as follows; 1. The effects of work hardening is high carbon steel greater than low carbon steel. 2. The effects of cracking as cold bending is high carbon steel greater than low carbon.
This study is to investigate the distribution of residual stress on the subsurface of the machining area. The operation was carry out within the range of normal working condition such as feed and cutting speeds. Turning operation was carry out orthogonal cutting condition on carbon alloy steel (SCM 4). The results are as follows. 1) It can be seen that in all cases the residual stress generate at the beneath of surface, it is increased to the maximum residual stress and then decreased. The maximum residual stress was located 4-25 un depth from the machining surface. 2) As the cutting speed increased maximum residual stress was increased to the certain speed (80-120 m/min) and then decreased. 3) As the feed rate increased, maximum residual stress also increased, the depth of maximum residual stress layer was deeper from the machining surfaces.
Since the LPG has higher octane number and lower maximum combustion temperature than gasoline, the LPG engine work in many other operating range, analysis the operating range preciously and provides reducing method of emission for the LPG engine. An electronic control unit(ECU) for the LPG engine using a feedback mixer is presented. A PI-controller is implemented in the ECU in order to handle air/fuel ratio control. The experimental result exhibit the required engine performance are satisfied in the each operating range.
본 논문에서는 압전필름을 특징으로 하는 스마트 구조물의 동적 모델링과 능동 진동제어를 수행하였다. 먼저, 압전필름을 복합재료판의 상하면에 각각 액튜에이터와 센서로 부착하여 스마트 구조물을 제작하였다. 그리고 동적 모델링을 압전필름의 액튜에이팅 특성과 구조물의 에너지를 적용하여 실시한 후, 신경망회로와 슬라딩모드 제어 개념을 연계한 신경 슬라이딩모드 제어기를 제안하였다. 한편, 시물레이션과 실험적 구현을 통해 과도진동과 강제진동에 대한 능동 진동제어를 수행하여 제시된 동적 모델링과 제어방법론의 타당성을 입증하였다. This paper presents dynamic modeling and vibration control of smart structures featuring piezoelectric films(PFs). A smart structure is firstly constructed by perfectly bonding two PFs on the upper and lower surfaces of host material structures (glass/epoxy) as an actuator and a sensor, respectively. Adoption Hamilton's principle with PF actuating dynamics, a governing equation for the lateral motion and associated boundary conditions are obtained. Furthermore, a neural network controller so called neuro-sliding mode controller(NSC) is fabricated to perform vibration control of the smart structure. The effectiveness of the methodology on dynamic model and control strategy is demonstrated by achieving vibration performances through numerical simulations and experimental implementations in both the transient and forced vibrations.
Active control of acoustic noise is an application area of adaptive digital signal processing with increasingly interest along the last year. This work studied the implementation of the multichannel LMS filter and the application of this algorithm for the reduction of the noise inside a vechicle cabin using a number of 'secondary sources' drived by adaptive filtering of a reference noise source. Firstly, we propose the use of adaptive method for the time-varient optimal convergence factor. Secondly, we propose the use of adaptive delayed inverse model to estimate the elastic-acoustic transfer function presented in vechicle cabin. The original, primary source is often periodic, with a known fundamental frequency. A suitably filtered reference signal can thus be used to drive the secondary sources. An algorithm is presented for adapting the coefficients of an FIR filter feeding such a secondary source in such a way as to minimize the output of a suitably placed microphone. In this algorithm, the coefficients of adaptive filter driving an array of secondary sources can be adapted to minimize the sum of the squares of the outputs of a number of error microphones. The multichannel LMS algorithm displays that such an algorithm is considered suitable to used for the global suppression of noise in vechice cabin.