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유연한 PDMS 재료의 마이크로 프레넬 렌즈의 스트레칭 실험에 관한 연구
이왕훈(Wanghun Lee),Truong Van Vu,신부현(Buhyun Shin),이호철(Hocheol Lee) 한국생산제조학회 2021 한국생산제조학회지 Vol.30 No.5
This study proposes an experimental stretching method and its effect using a flexible micro Fresnel lens made from polydimethylsiloxane (PDMS) material with 25 mm diameter, 1mm thickness. The PDMS lens is strained by a four-degree-of-freedom (DOF) stretching device to change the lens’s curvature. This stretching device consists of four linear stepping motors, placed concentric symmetry at the center of the PDMS lens. Each motor is operated via an A4988 stepper driver that receives the speed signal from the Arduino UNO controller. The simulation and experimental results are implemented to analyze and validate the performance of the stretched lens. The results indicated an increment of about 8% of the diameter and 12.3% of the imaging change after the stretching process.
이왕훈(Wanghun Lee),레광환(Quang Hoan Le),강현수(Hyunsoo Kwang),박태영(Taeyoung Park),신기연(Kiyeon Shin),신현상(Hyeonsang Shin),신부현(Buhyun Shin) 대한기계학회 2021 대한기계학회 춘추학술대회 Vol.2021 No.11
This study proposes a novel design of a hybrid leg-wheel quadruped robot which comprises 2 DOFs (prismatic joint and revolute joint) for leg and one rotational joint for wheel. The robot is able to utilize on rough terrain by conducting walking gait or to drive rapidly on the flat ground via wheels. Firstly, the design of structure and mechanism are illustrated based on analysis of the function and performance requirement. The design indicates that the robot is able to conduct several movement modes to adapt to diverse surfaces. Then, the gait of legged mode is also presented with three supporting legs and one transferring leg. There are totally six motion steps of the walking algorithm for the quadruped robot. Besides, the robot can drive several situations when conducting leg-wheel hybrid mode. The performance for the robot locomotion is validated by using Matlab SimscapeMultibody software. The simulation result indicated that our proposed robot has ability to implement successfully on both flat surface of rough terrain.
소형 광전자 센서를 이용한 소형 진자형 전자기 구동기의 피드백 제어
이왕훈(Wanghun Lee),노요한(Yohan Noh),신부현(Buhyun Shin),김영식(Youngshik Kim) 대한기계학회 2021 大韓機械學會論文集A Vol.45 No.5
소형 진자형 전자기 구동기의 피드백 제어를 위해서 소형 반사식 광전자 센서를 사용하였다. 제작된 센서 보드는 6 mm×5 mm의 크기로 충분히 소형으로 제작되었다. 측정 거리는 최대 3 mm까지 측정이 가능하다. 개발된 소형 진자형 구동기에 부착하여 구동부의 변위를 측정한다. 개발된 소형 진자형 구동기는 2차 선형시스템으로 모델링되었다. 시뮬레이션과 실험을 통하여 계단응답 특성을 확인한 결과 미흡 감쇠 응답특성을 확인하였다. 제안된 반사식 광전자 센서를 통해 변위를 되먹임을 받아 PID 피드백 제어를 수행하였다. 피드백 제어를 이용해서 계단 응답 특성에서 초과와 진동이 감소함을 확인하였다. 초과는 약 20%에서 약 3%로 정착시간은 약 0.06 s에서 약 0.04 s로 개선되었다. A tiny optoelectronic sensor is used for the feedback control of a miniaturized oscillatory electromagnetic actuator. The size of the sensor board used is 6 mm × 5 mm, which is small enough to be attached inside the actuator for measuring the operating distance. The developed oscillatory electromagnetic actuator is modeled using a second order linear system. Underdamped responses are obtained when step inputs are applied to the actuator in the simulation and experiments. The PID controller is developed and implemented using feedback signals from the proposed optoelectronic sensor. The proposed controller reduces the overshoot and settling time in the step response from 20% to 3% and from 0.06 s to 0.04 s, respectively.