• International Journal of Fuzzy Logic and Intelligent Systems
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• 제14권2호
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• pp.136-144
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• 2014

The existing conventional motion controller does not perform well in the presence of nonlinear properties, uncertain factors, and servo lag phenomena of industrial actuators. Hence, a feasible and effective fuzzy self-tuning proportional integral derivative (PID) and feed-forward control scheme is introduced to overcome these problems. In this design, a fuzzy tuner is used to tune the PID parameters resulting in the rejection of the disturbance, which achieves better performance. Then, both velocity and acceleration feed-forward units are added to considerably reduce the tracking error due to servo lag. To verify the capability and effectiveness of the proposed control scheme, the hardware configuration includes digital signal processing (DSP) which plays the main role, dual-port RAM (DPRAM) to guarantee rapid and reliable communication with the host, field-programmable gate array (FPGA) to handle the task of the address decoder and receive the feed-back encoder signal, and several peripheral logic circuits. The results from the experiments show that the proposed motion controller has a smooth profile, with high tracking precision and real-time performance, which are applicable in various manufacturing fields.

• 한국전자파학회논문지
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• 제29권6호
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• pp.411-414
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• 2018

본 논문에서는 FMCW 레이다 기반으로 휴먼 모션 인식을 위한 레이다 영상 추출 알고리즘을 제안하였다. 3D(거리-속도-각도) 스펙트럼을 생성하였고, 각 좌표방향으로 압축을 통해 세 개의 마이크로-프로파일 영상을 생성하였다. 이때 몸으로부터 반사된 신호를 억제하기 위한 클러터 억제 알고리즘을 적용하였다. 생성된 거리, 도플러. 각도-영상을 향후 영상처리 및 분류기에 적용함으로써, 다양한 모션 종류를 구별할 수 있을 것으로 판단된다.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제10권2호
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• pp.113-118
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• 2010

This paper proposed an ECAM (Electronic cam) control system which has simple and general structure. The proposed cam controller adopted the linear and polynomial curve-fitting method to generates a smooth cam profile curve function. Smooth motion trajectory of master actuator guarantees the good performance of slave motion and has an important effect on the interpolation quality of ECAM. The auto-tuning PID velocity controller was applied to overcome the uncertainties in ECAM, and the gains of the controller are updated continuously to ensure the consistency of system performance under varying working conditions. The robustness of system against the varying load torque disturbances and noises is guaranteed by using the load torque disturbance observer to suppress the disturbance on master actuator. The velocity compensator was applied to compensate the degradation of performance of slave motion caused from the varying driving speed of master motion. The stability and validity of the proposed ECAM control system was verified by simulation results.

• 한국통신학회논문지
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• 제33권6C호
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• pp.459-470
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• 2008

In this paper, we propose a fast ME (motion estimation) algorithm for MPEG-4 to H.264 Transcoder. Whereas 2 modes ($8{\times}8$, $16{\times}16$) are used for ME in MPEG-4 simple profile, ME using 7 modes is supported for further enhanced coding efficiency in H.264. The transcoding speed is affected dominantly by the computational complexity of encoder part in transcoder, where ME module of H.264 encoder has high complexity due to using 7 modes. In order to increase the speed of transcoding between MPEG-4 and H.264, we use 3 PMVs (predicted motion vectors) and the mode information of MBs (macroblocks) provided from the decoder part of transcoder. Since the proposed 3 PMVs are very close to an optimal motion vector, and we consider only some restricted modes according to the MB information transferred from decoder part, the proposed scheme can speed up the transcoding procedure without loss of image quality. We show experimental results which demonstrate the effectiveness of the proposed algorithm, where performance of our scheme is compared with that of the conventional fast algorithm for H.264.

• 대한기계학회논문집A
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• 제36권4호
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• pp.387-393
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• 2012

본 논문에서는 기존 랙-피니언 시스템의 랙 치형을 핀 또는 롤러로 대체한 롤러 랙 피니언 (RRP) 시스템의 표면피로 향상방안을 고찰하였다. 우선 전위계수(profile shift coefficient)를 고려하여 RRP 시스템의 캠 피니언(cam pinion)에 대한 엄밀 치형설계 방법 및 언더컷 방지 조건을 소개하였고, 이를 바탕으로 설계인자의 변화에 따른 하중 및 하중응력계수(load stress factor)의 변화를 검토하였다. 이를 통해 RRP 시스템의 표면 내구성을 향상시킬 수 있는 방안으로 전위계수의 증가가 효과적임을 알 수 있었다.

• 대한기계학회논문집A
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• 제35권11호
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• pp.1453-1459
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• 2011

외접기어의 어느 한쪽 기어를 핀 또는 롤러로 대체한 롤러 피니언 기어 (RPG) 시스템은 기어 치물림 시 미끄럼 접촉을 줄이고 구름운동을 증대시켜 기어 내구성을 향상시킬 수 있다. 우선 본 논문에서는 전위계수(profile shift coefficient)를 고려하여 RPG 시스템의 캠 기어(cam gear)의 엄밀 치형설계 방법 및 치 꼬임으로 인한 간섭 방지조건을 제시하였다. 또 기어구동에 있어 치면에서 발생되는 진동이나 소음의 원인이 되는 피팅(pitting) 발생수명을 고려하기 위해, 설계인자의 변화에 따른 Hertz 접촉응력 및 하중응력계수(load stress factor)의 변화를 검토하였다. 이를 통해 RPG 시스템의 내구성을 향상시킬 수 있는 방안으로 전위계수의 증가를 제안하였다.

• 대한족부족관절학회지
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• 제17권4호
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• pp.302-308
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• 2013

Purpose: To present clinical results of proximal first metatarsal opening wedge osteotomy and low profile plate fixation in hallux valgus deformity. Materials and Methods: Thirty-two patients (39 feet) underwent surgery for hallux valgus deformity. Fourteen patients (18 feet; Group A) underwent proximal first metatarsal opening wedge osteotomy fixed with low profile titanium plate ($Arthrex^{(R)}$), and 18 patients (21 feet; Group B) underwent proximal chevron osteotomy with two K-wires. Improvement in hallux valgus angle (HVA), 1, 2 intermetatarsal angle (IMA), range of motion of 1st metatarsophalangeal joint, VAS score, and the length of first metatarsal on weight-bearing radiograph were evaluated preoperatively and at final follow-up. Results: HVA improved from $36.2{\pm}6.6$ degrees to $11.7{\pm}5.1$ degrees, and 1, 2 IMA improved from $15.7{\pm}2.6$ degrees to $7.2{\pm}1.9$ degrees. VAS score improved from $7.2{\pm}1.2$ to $1.4{\pm}0.9$. There were no significant differences clinically and radiologically. Conclusion: Proximal first metatarsal opening wedge osteotomy with stable fixation using low profile plate may be an effective surgical option for correction of hallux valgus deformity.

• 한국산학기술학회논문지
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• 제11권6호
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• pp.1955-1960
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• 2010

CNC 3축 파이프 형상절단기의 성능은 이송계의 위치결정 정밀도와 공작물의 가공 정밀도를 측정하고 검증함으로써 평가되었다. 위치결정 정밀도는 PLC의 모션 컨트롤러에 의하여 구동된 이송 거리와 레이저 간섭계를 이용 한 실제 이송 거리를 측정 비교하여 오차를 확인하였다. 그리고 가공 정밀도는 절단된 공작물을 스캐닝하고 3D 모델링하여 가공형상을 확보하고, 절단궤적에 해당하는 CL 데이터와 비교하여 오차를 확인하였다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2006년도 춘계학술대회 논문집
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• pp.267-268
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• 2006

Cam mechanisms are one of the most popular devices for generating irregular motion and are widely used in many industrial areas. The purpose of this study is the development of high precision measuring system fur measurement data acquisition and analysis of a manufactured cam profile. The developed system is composed of servo motor, CNC controller, rotary encoder, and laser interferometer And also, this system is non-contact measuring type. The developed system takes only 5 minutes to measure a cam profile and to analyze the measuring data while the CMM(coordinate measuring machine) takes about 1 hours even by a skilled operator.

• 한국정밀공학회지
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• 제16권4호통권97호
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• pp.37-45
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• 1999

Many automated welding equipment are used in the industry. However, there are some problems to get quality welds because of the geometric error, thermal distortion, and incorrect joint fit-up. These factors can make the gap between base plates in case of a thick plate welding. The welding product with the quality welds can not be obtained without consideration of the gap. In this paper, the robot path and welding conditions are modified to get the quality weld by detecting the position and size of the gap. In this work, a low-priced laser range sensor is used. The 3-dimensional information is obtained using the motion of a robot, which holds a laser range sensor. The position and size of the gap is calculated using signal processing of the measured 3-dimensional information of joint profile geometry. The data measured by a laser range sensor is segmented by an iterative end point method. The segmented data is optimized by the least square method. The existence of gap is detected by comparing the data with the segmented shape of template. The effects of robot measuring speed and gap size are also tested. The recognizability fo the gap is verified as good by comparing the real joint profile and the calculated joint profile using the signal processing.