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보행속도를 고려한 관성센서 기반의 실시간 발-지면 접촉검출 알고리즘 개발에 관한 연구
김명규(Myeongkyu Kim),이동훈(Donghun Lee) 대한기계학회 2015 대한기계학회 춘추학술대회 Vol.2015 No.11
This paper deals with the development of IMU based real-time Foot-Ground Contact Detection (FGCD) algorithm considering the variations of walking speed. To estimate the location and walking speed of pedestrian in the GPS-denied environment, IMU based lower-limb kinematics is a proper method, and in order to solve the lower-limb kinematics, the information of the contact between foot and ground should be obtained in real-time. To develop the IMU based FGCD algorithm available at various walking speed, the subjects with IMUs on the lower-limb walked on the flat ground with three levels of walking speed. As results of gait analysis based on the IMU output signal, the four main parameters showing significant changes at the four steps of stance phase are discovered. Using the thresholds and peak values of the main parameters at the four steps of stance phase, the IMU based real-time FGCD algorithm is successfully developed.
방켈 로터리 엔진의 포트 형상 및 로터 리세스 슬롯 유무에 따른 엔진 내 유동에 대한 수치 해석적 연구
김청환(Cheonghwan Kim),박성호(Sungho Park),김명규(Myeongkyu Kim),고준만(Junman Ko),김정우(Jeongwoo Kim),안은수(Eunsoo Ahn) 한국추진공학회 2022 한국추진공학회 학술대회논문집 Vol.2022 No.5
방켈 로터리 엔진은 하우징 내부의 로터가 편심축을 중심으로 회전하면서 작동하는 내연 기관의 한 형태이다. 방켈 로터리 엔진은 배기량 대비 출력이 높다는 특성 때문에 기관 중량 대비 높은 비출력의 확보가 필요한 무인 항공기의 추진 장치로 적합한 것으로 평가받고 있다. 그러나 납작한 형태의 연소실 형상으로 인해 화염의 소멸이 발생하는 면적이 넓고 불완전한 연소가 쉽게 발생해 연소 효율이 낮은 실정이다. 이러한 문제를 해결하거나 최소화한다면 방켈 로터리 엔진 성능의 큰 개선을 이룰 수 있을 것이다. 본 연구에서는 3차원 전산 유체 해석을 통해 방켈 로터리 엔진의 흡기 포트 단면 형상 및 로터 리세스 슬롯 유무에 따른 연소실 내 유동 변화를 확인하였다. 연소실 내 일부 지점에서 난류 강도를 취득하고 포트 유량을 비교하여 방켈 로터리 엔진의 설계 변화에 따른 유동 변화를 확인하였다. Wankel rotary engine is one of the Internal Combustion Engines worked by rotating a eccentric rotor inside an engine housing. Wankel rotary engine is considered as a suitable propulsion device for unmanned aerial vehicles because it provides high power-to-weight and power-to-volume ratio. However its long and narrow combustion chamber induces and larger quenching zones and incomplete combustion, which result in poor combustion efficiency. Resolving or minimizing these problems could lead to improvements in Wankel rotary engine performance. In this paper, flow characteristics such as turbulent kinetic energy and mass flow rate through the intake port by cross-section design of the intake port and the presence of a rotor recess slot was evaluated by three-dimensional computational fluid dynamics.
소형 2행정 엔진의 전송 포트 형상에 따른 소기 성능에 대한 수치 해석적 연구
김청환(Cheonghwan Kim),박성호(Sungho Park),김명규(Myeongkyu Kim),안은수(Eunsoo Ahn) 한국추진공학회 2020 한국추진공학회 학술대회논문집 Vol.2020 No.7
본 연구에서는 무인 항공기용 소형 2행정 엔진의 성능 개선을 위해 다양한 전송 포트 형상의 가스 교환 성능을 평가하였다. 성능 평가를 위해 네 가지 전송 포트 형상에 따른 3차원 전산 유체 해석을 진행하였으며, 가스 교환 성능의 정량적 평가를 위해 이상적 소기 모델인 완전 대체 소기 모델과 완전 혼합 소기 모델을 바탕으로 새로운 3단계 소기 모델을 개발하여 해석 결과에 적용하였다. 2행정 엔진의 전송 포트 형상 변경을 통해 흡기의 단락 현상을 효과적으로 줄였으며 가스 교환 과정 동안의 실린더 내 난류 에너지 또한 크게 개선되었다. 또한, 전송 포트 형상 별 3단계 소기 모델의 적용을 통해 가스 교환 성능을 정량적으로 평가할 수 있었으며, 포트 형상 별 소기 양상의 차이를 확인할 수 있었다. In this paper, the scavenging process of various transfer ports was evaluated to improve the performance of a small two-stroke engine for unmanned aerial vehicles. Three-dimensional computational fluid dynamics simulations were performed to four transfer ports for the evaluation, and a three-phase scavenging model was developed and applied to the simulation results for the quantitative comparison of scavenging performance. the short-circuit of fresh charge was restrained and an in-cylinder turbulent kinetic energy was enhanced by changing the transfer port. Also, a difference in the scavenging for each port were confirmed by applying the three-phase model to the simulation results.
소형 2행정 엔진의 전송 포트 형상에 따른 소기 성능에 대한 수치 해석적 연구
김청환(Cheonghwan Kim),박성호(Sungho Park),김명규(Myeongkyu Kim),안은수(Eunsoo Ahn) 한국추진공학회 2020 한국추진공학회지 Vol.24 No.6
In this paper, the scavenging process of various transfer ports was evaluated to improve the performance of a small two-stroke engine for unmanned aerial vehicles. Three-dimensional computational fluid dynamics simulations were performed to four transfer ports for the evaluation, and a three-phase scavenging model was developed and applied to the simulation results for the quantitative comparison of scavenging performance. the short-circuit of fresh charge was restrained and an in-cylinder turbulent kinetic energy was enhanced by changing the transfer port. Also, a difference in the scavenging for each port were confirmed by applying the three-phase model to the simulation results.
극한 환경용 일체형 구동기의 원격 제어 및 모니터링 시스템의 속도 향상에 관한 연구
황인상(Insang Hwang),김명규(Myeongkyu Kim),고석진(Sukjin Ko),이동훈(Donghun Lee) 대한기계학회 2015 대한기계학회 춘추학술대회 Vol.2015 No.11
This paper is a study on development of tele-operation and monitoring system of an airtight all-in-one actuator for working robots in harsh environment like industry sites and scenes of a nuclear accident. Developed actuator is assembled with harmonic driver reducer and DC Servo Motor, EtherCAT Servo Driver in single housing and has structure of airtight property. This paper constructs the system that can remote control and monitor the airtight all-inone actuator with high speed on the basis of TCP/IP communication under real time controller platform of National Instrument. Also, performance of tele-operation and monitoring in accordance with increase of the number of actuators is evaluated in terms of update rate and packet data Loss.
하현주 ( Ha Hyunju ),김명규 ( Kim Myeongkyu ),이치호 ( Lee Chiho ),오민석 ( Oh Minseok ) 대전대학교 한의학연구소 2016 혜화의학회지 Vol.25 No.1
Objectives : The aim of this study was to report the cases of knee injury that are treated with both CPM and Korean medicine. Methods : We treated 3 patients who had knee joint pain and gait disturbance by knee injuries with Korean medicine and CPM treatment. We evaluated the outcomes by checking NRS, ROM, Lysholm knee score, walking state and other symptoms. Results : The NRS, ROM, Lysholm knee score, and other symptoms of 3 patients were improved before they. These results show possibilities of simultaneous treatment of Korean medicine and CPM. But there is a limit that the number of cases is not sufficient, and there was no long-term follow-up after discharge. Conclusions : Simultaneous treatment of Korean medicine and CPM has an effect on knee joint rehabilitation. Further studies are needed to prove the effectiveness of Korean medicine combined with CPM.
모바일 로봇의 험지 주행 성능 향상을 위한 기구학 기반 제어 모델 개발
황인상(Insang Hwang),고석진(Sukjin Ko),김명규(Myeongkyu Kim),신영광(Youngkwang Shin),이동훈(Donghun Lee) 대한기계학회 2016 대한기계학회 춘추학술대회 Vol.2016 No.12
This paper describes a new kinematic model to improve the trajectory tracking performance of a four-track mobile robot with a passively articulated suspension. The mobile robot is composed of four tracks, two rockers, 2-DOF pitch-roll joints, a differential gear, and a main body. Due to the difficulties in the explicit identification of wheel-terrain contact angles through elevation map or GPS information, tiltable driving tracks are combined with suspension kinematics to identify track-terrain contact angles for the proposed mobile robot in arbitrarily rough terrains. That is, the TTCA-based driving velocity projection method is proposed in this study to improve the maneuverability of the proposed mobile robot in arbitrarily rough terrains. Virtual ground with a sinusoidal shape is modeled in the DAFUL-Simulink co-simulator framework to examine the improvement in the proposed mobile robot relative to a non-suspension version of a four-track mobile robot. The results indicate that the proposed mobile robot has a 33.3% lower RMS distance error, 56.3% lower RMS directional error, and 43.2% lower RMS offset error than the four-track SSMR, even with planar SSMR kinematics. And the results show that PASTRo with the TTCA-based driving velocity projection method has a 39.2% lower RMS distance error, 57.9% lower RMS directional error, and 51.9% lower RMS offset error than the four-track SSMR.