• 제어로봇시스템학회논문지
• /
• 제22권12호
• /
• pp.1027-1033
• /
• 2016

There is an increasing need for manufacturing systems to produce batches in small quantities. Such manufacturing systems are significantly difficult to develop with conventional automation equipment. Recently, several research groups have applied industrial dual-arm robots to cell production lines. A synchronization method for robots is necessary for the cell production process when robots work in a shared workspace. Conventional automation factories do not need this method because the main control system operates all of the machines or robots. However, our intended application for the developed robot is in small manufacturing environments that cannot install an expensive main control system. We propose an inexpensive and high-performance method with a simple digital in/out channel using a real-time communication protocol. The developed method was validated in a pilot production line for cellular phone packing.

• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 2003년도 신호처리소사이어티 추계학술대회 논문집
• /
• pp.417-420
• /
• 2003

Most Embedded Web Camera Server products currently deployed on the market adopt JPEG for compression of video data continuously acquired from the cameras. However, JPEG does not efficiently compress the continuous video stream, and is not appropriate for the Internet where the transmission bandwidth is not guaranteed. In our previous work, we presented the result of designing and implementing an embedded web camera streaming server using MPEG4 codec. But the server in our previous work did not show good performance since one CPU had to both compress and process the network transmission. In this paper, we present our efforts to improve our previous result by using dual CPUs, where DSP is employed for data compression and StrongARM is used for network processing. Better performance has been observed, but it is found that still more time is needed to optimize the performance.

• 대한물리의학회지
• /
• 제17권1호
• /
• pp.85-92
• /
• 2022

PURPOSE: This study aimed to analyze the effects of task exercise on an unstable surface on the involuntary arm and leg movement and balance in stroke patients. METHODS: 20 stroke patients were clinically sampled and randomly assigned to two groups of 10 patients each. Experimental group I received task exercise intervention on an unstable surface and experimental group II received task exercise intervention. The interventions were carried out 3 times a week for 4 weeks (30 minutes per session). The global synkinesis (GS) and Berg Balance Scale (BBS) of the patients were evaluated as pre-tests prior to intervention, and then the post-tests were re-measured in the same manner as the pre-tests after a 4-week intervention period. RESULTS: In the experimental group I, there were statistically significant differences in the changes in the arm and leg GS (p < .01) and in the BBS (p < .05). On the other hand, in the experimental group II, there were statistically significant differences in the changes only in the arm GS (p < .01) and in the BBS (p < .05). Also, in the comparison of the changes between the two groups, there was a statistically significant difference in the changes in the leg GS only (p < .05). CONCLUSION: In the experimental group I, the arm and leg GS were statistically significantly reduced, but the balance ability was statistically significantly improved. The reason was that in the experimental group I, similar movements of the paralyzed arm were promoted due to the double-task exercise on the unstable surface, and sensory feedback and posture strategies were well utilized in the legs, which was found to be effective in reducing the GS and improving the balance ability. Therefore, based on these results, the double-task exercise on an unstable surface should be fully utilized for the rapid rehabilitation of stroke patients.

• 로봇학회논문지
• /
• 제15권3호
• /
• pp.293-300
• /
• 2020

The purpose of our sensor system is to transparentize the large hydraulic manipulators of a six-ton dual arm excavator from the operator camera view. Almost 40% of the camera view is blocked by the manipulators. In other words, the operator loses 40% of visual information which might be useful for many manipulator control scenarios such as clearing debris on a disaster site. The proposed method is based on a 3D reconstruction technology. By overlaying the camera image from front top of the cabin with the point cloud data from RGB-D (red, green, blue and depth) cameras placed at the outer side of each manipulator, the manipulator-free camera image can be obtained. Two additional algorithms are proposed to further enhance the productivity of dual arm excavators. First, a color correction algorithm is proposed to cope with the different color distribution of the RGB and RGB-D sensors used on the system. Also, the edge overlay algorithm is proposed. Although the manipulators often limit the operator's view, the visual feedback of the manipulator's configurations or states may be useful to the operator. Thus, the overlay algorithm is proposed to show the edge of the manipulators on the camera image. The experimental results show that the proposed transparentization algorithm helps the operator get information about the environment and objects around the excavator.

• 한국소음진동공학회논문집
• /
• 제14권5호
• /
• pp.385-393
• /
• 2004

This paper proposes a swing-arm type dual-stage actuator, which consists of a PZT actuator for fine motion and a VCM(voice coil motor) for coarse motion, for an SFF ODD(small form factor optical disk drive), in order to achieve fast access speed and precise track-following control. Over the past few decades there have been a lot of researches related to the VCM and dual-stage actuator. In this paper, we focus our attention on the design and control of the PZT actuator. Due to the dual cantilever structure. the PZT actuator can generate precise translational tracking motion at its tip to which an optical pickup is attached. and the effect of hysteric behavior of the PZT element is reduced. The dynamic model of the PZT actuator is derived by using the Hamilton's principle, and verified by comparing it with the experimental frequency response. The sliding mode control is designed in order to be robust against modeling uncertainties. Simulations and experimental results confirm the effectiveness of the suggested control scheme.

• 전기학회논문지
• /
• 제64권2호
• /
• pp.232-239
• /
• 2015

Faced with unbalanced grid operation mode, the high voltage direct current (HVDC) based on voltage source converter (VSC) can be properly controlled by a dual current control scheme. For the modular multilevel converter (MMC) controlling the AC side current is able to limit the arm current which flows along the IGBT of submodule (SM) to rated current. However the limitation of the arm current results in leaving the control range of active power at MMC confined to below the rated capacity. As a result, limiting the arm current causes the problem that the DC side voltage of the HVDC can not be controlled to the reference value since MMC HVDC adjusts the DC side voltage through the active power. In this paper, we propose the algorithm adjusting the active powers of both MMCs to resolve the problem. The back-to-back MMC HVDC applying the algorithm is modeled by PSCAD/EMTDC to verify the algorithm.

• 대한물리의학회지
• /
• 제19권2호
• /
• pp.91-98
• /
• 2024

PURPOSE: This study aimed to provide basic clinical data by investigating the impact of Activities of daily living-related dual-task intervention on lung function, balance, and Activities of daily living of stroke patients. METHODS: After sampling 40 stroke patients who met the selection criteria, this study randomly assigned 20 patients who received dual-task exercise intervention to the experimental group and 20 patients who received single exercise intervention to the control group by drawing lots. Next, the study pre-tested their lung function, balance, and activity of daily living. All interventions were conducted for 30 minutes, 3 times a week for 4 weeks, and when all interventions were completed after 4 weeks, lung function, balance, and activity of daily living were re-measured in the same way as the pre-test. RESULTS: In comparing changes in lung function, balance, and activity of daily living within each of the experimental and control groups, statistically significant improvement were found in the experimental group only (p < .01). Statistically significant improvement were also found in lung function, balance, and activities of daily living between the groups (p < .05) (p < .01). CONCLUSION: A statistically significant improvements were found in lung function, balance, and activities of daily living only in the experimental group and statistically significant differences were found between groups. Because they take arm exercises by maintaining balance in a standing position on a labile surface and through dual-task exercise such as folding a towel, moving a cup, and throwing and catching a ball, muscles related to lung function were stimulated and lung function and balance were improved. This helped activities of daily living to be improved. Thus, it is considered that dual-task exercise should be utilized for stroke patients' smooth everyday life.

• 한국공작기계학회:학술대회논문집
• /
• 한국공작기계학회 2003년도 춘계학술대회 논문집
• /
• pp.327-339
• /
• 2003

In this paper, a self-organizing fuzzy controller(SOFC) for the industrial robot manipulator with a actuator located at the base is studied A fuzzy login composed of linguistic conditional statements is employed by defining the relations of input-output variable of the controller, In the synthesis of a FLC, one of the most difficult problems is the determination of linguistic control rules from the human operators. To overcome this difficult SOFC is proposed for a hierarchical control structure consisting of basic level and high level that modify control rules. The proposed SOFC scheme is simple in structure, fast in computations and suitable for implementation of real-time control. Performance of the SOFC is illustrated by simulation and experimental results for robot with low joints.

• 드라이브 ㆍ 컨트롤
• /
• 제13권4호
• /
• pp.95-101
• /
• 2016

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2019년도 추계학술대회
• /
• pp.37-39
• /
• 2019

본 논문에서는 듀얼 벅 멀티레벨 컨버터의 일반화된 회로구성을 제안한다. 기존의 멀티레벨 컨버터는 스위칭 상태 전환시암(arm)의 단락을 의미하는 슛-스루(shoot-through) 문제가 존재하므로 데드 타임이 필수적으로 요구되지만 제안되는 듀얼 벅 멀티레벨 컨버터에서는 이러한 문제점이 해결된다. 본 논문에서는 시뮬레이션과 실험을 통하여 제안되는 듀얼 벅 멀티레벨 컨버터의 효과와 유효성을 검증한다.