• Journal of Practical Engineering Education
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• v.10 no.2
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• pp.113-118
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• 2018

The most important thing in vocational education and training is to enhance students' interest and understanding of the whole process of the production site. In this paper, we present a case on the implementation of tele-operation robot hand by learning factory based technology convergence education. It also suggests some points to be taken when applying the learning factory in the future curriculum. In order to implement the tele-operation robot hand, it is necessary to support the compulsory subjects of university level courses in domestic curriculum such as mechanic design, motor control, local communication implementation, sensing and feedback control. The educational research presented in this paper guides the students with the skills they need and understands the skills through self-study and practice, and implements the final products. This study will be useful as a base data when introducing the training process of training factory in the future.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.47 no.4
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• pp.289-299
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• 2019

Attitude control modeling and simulation (M&S) can be extensively applied in overall development process, from simple algorithm design to on-board software verification. This paper introduces CMG-based attitude control M&S software, which consists of 6-DOF modeling (CMG and space environments modeling), and attitude control algorithm. The M&S software is divided into three modules, from an inner CMG motor control module to an outer earth observation mission module. While an application of this developed software is currently limited to the initial-phase attitude controller development, its application area can be extended to the later-phases by considering sophisticated model information in future.

• PNF and Movement
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• v.17 no.1
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• pp.31-39
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• 2019

Purpose: Cognitive function is a main concern for rehabilitation progression in individuals who have sustained brain damage, even among those whose motor function has returned after brain damage. The purpose of this study was to investigate how cognitive impairment relates to functional independence in postural stability and gait performance in patients with chronic hemiparetic stroke. Methods: This was an observational design in an outpatient rehabilitation hospital. Twenty-eight adults with chronic hemiparetic stroke, receiving a course in an outpatient rehabilitation program, participated in this study. They were divided into two groups (i.e., non-cognitive impairment and cognitive impairment groups) via a cut-off score of 23 or less on a mini-mental state examination. Functional independence was assessed with the timed up-and-go test (TUG), 10-meter walk test (10mWT), five times sit-to-stand test (FTSST), Berg balance scale (BBS), and modified Barthel index (MBI). The independent t-test was used for statistical analysis when comparing the two groups. Results: The cognitive impairment group had less functional independence, balance, and gait performance than those of the non-cognitive impairment group had. The former also showed a statistically significant decrease in their TUG score, FTSST score, BBS score, and MBI score compared to the latter, but not in their 10mWT score (p<0.05). Although the non-cognitive impairment group walked faster than the cognitive impairment group did, that difference was not statistically significant (p>0.05). Conclusion: The results of this study suggest that cognitive impairment relates to functional independence in postural stability and the activities of daily living. In rehabilitation settings, cognitive impairment would be considered a major component in therapeutic rehabilitation to overcome the patients difficult physical problems and to treat for improving functional independence more after stroke.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.13 no.6
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• pp.483-488
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• 2020

In recent years, the demand for wireless devices incorporating several wireless communication systems into one has been increasing in order to provide services that meet the diverse needs of consumers. Wireless devices consisting of various wireless communication systems require many frequency fixed filters. A frequency tunable filter can replace a number of frequency fixed filters in the wireless devices. If a frequency tunable filter is used in wireless systems, the system can be configured more efficiently. In this paper, a 3-pole frequency tunable BPF(bandpass filter) operating in the frequency band of 800 ~ 2400MHz is designed. In order to widen the operating frequency band, a tuning screw is designed to have a step and a linear motor is used to facilitate the adjustment of the tuning screw. The implemented frequency tunable BPF operates in the designed frequency range and has the maximum insertion loss of 2.82dB in the channel band and the minimum attenuation of 18.7dB at ± 50MHz frequency offset from the center frequency of the band.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.12
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• pp.62-69
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• 2020

The demand for industrial robots is proliferating with production automation. Industrial robots are used in various fields, such as logistics, welding, and assembly. Generally, six degrees of freedom are required to move freely in space. However, the palletizing robot used for material management and logistics systems typically has four degrees of freedom. In designing such robots, their main parts, such as motors and reducers, need to be adequately selected while satisfying payload requirements and speed. Hence, this study proposes a practical method for selecting the major parts based on dynamic analysis using ADAMS. First, the acceleration torques for the robot motion were found from the analysis, and then the friction torques were evaluated. This study introduces a constant-speed torque constant instead of friction coefficient. The RMS torque and maximum power of each motor were found considering the above torques. After that, this study recommends the major specifications of all motors and reducers. The proposed method was applied to a palletizing robot to verify the suitability of the pre-selected main parts. The verification result shows that the proposed method can be successfully applied to the early design stage of industrial robots.

• The Transactions of the Korean Institute of Power Electronics
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• v.26 no.3
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• pp.214-221
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• 2021

SiC MOSFETs require a faster and more reliable short-circuit protection circuit than conventional methods due to narrow short-circuit withstand times. Therefore, this research proposes a short-circuit protection circuit using a current-sensing circuit based on Rogowski coil. The method of designing the current-sensing circuit, which is a component of the proposed circuit, is presented first. The integrator and input/output filter that compose the current-sensing circuit are designed to have a wide bandwidth for accurately measuring short-circuit currents with high di/dt. The precision of the designed sensing circuit is verified on a double pulse test (DPT). In addition, the sensing accuracy according to the bandwidth of the filters and the number of turns of the Rogowski coil is analyzed. Next, the entire short-circuit protection circuit with the current-sensing circuit is designed in consideration of the fast short-circuit shutdown time. To verify the performance of this circuit, a short-circuit test is conducted for two cases of short-circuit conditions that can occur in the half-bridge structure. Finally, the short-circuit shutdown time is measured to confirm the suitability of the proposed protection circuit for the SiC MOSFET short-circuit protection.

• PNF and Movement
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• v.10 no.3
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• pp.7-18
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• 2012

Purpose : This study was to compare the difference Trunk Control Test(TCT), Postural Assessment Scale for Stroke(PASS-TC), and Trunk Impairment Scale(TIS) and its subscales in relation to the difference MBI(Modified Barthel Index), BBS(Berg Balance Scale), and to establish the association between MBI, BBS, Fugl Meyer-motor function(FM-M), and to predict MBI-subscales from the variables. Methods : 58 stroke patients, attending a rehabilitation programme, participated in the study. Trunk control was measured with the use of the TCT, PASS-TC, TIS, and the performance of Activities daily living was obtained by MBI, and dynamic balance ability(by BBS). Trunk control scores from the difference MBI, BBS were compared using the 1-way ANOVA(Mann Whitney U test) and the data were analyzed using Pearson product correlation. Multiple stepwise regression analyses were performed to identify prognostic factors for ADL subscale. Results : Trunk control scores showed significant differences between MBI(F=2.139~13.737, p<.05~.001), BBS(t=3.491~7.705, p<.01~.001). It was significantly related with value of the MBI(r=.25~.50), BBS(r=.38~.68), FMM( r=.31~.48). Stepwise linear regression analysis showed an additional, significant contribution of the TCT, in addition to the PASS-TC, dynamic sitting balance subscale of the TIS for measures of MBI subscales. Conclusion : Measures of trunk control were significantly related with values of MBI, BBS score, so the management of trunk rehabilitation after stroke should be emphasized. The use of both quantitative and qualitative scales was shown to be a good measuring instrument for the classification of the general performance of the stroke patients. Further study about trunk control is needed using a longitudinal study design.

• Physical Therapy Rehabilitation Science
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• v.10 no.2
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• pp.212-216
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• 2021

Objective: Mirror therapy is one of the promising methods suggested for the upper limb rehabilitation of stroke patients. While mirror therapy was presented to be effective in improving motor function of stroke patients, problems were raised as preceding studies had various methods in applying mirror therapy. Some studies even reported no effect in mirror therapy. Our supposition for the reason of such problems was a decrease of attention on the illusive image during mirror therapy of stroke patients, and we aimed to observe this. Design: A cross-sectional preliminary study. Methods: Three hemiplegic acute patients were recruited for the traditional mirror therapy. It lasted for 30 minutes, and 12 different tasks were asked to perform. All procedures were video-recorded, and Observer XT was used to analyse mirror-gazing time, gaze-distracted time, preparation time, frequency of mirror gazing, frequency of distraction, frequency of preparation for treatment. Results: Subjects spent an average of 4-5 minutes having instructions about the mirror therapy intervention (preparation duration), an average of 11 minutes watching the mirror during therapy (mirror-gazing duration), and the rest of 14-15 minutes looking around the environment (gaze-distracted duration). During the mirror therapy, the number of distracted moments (frequency of distraction) was eight times more than focusing on the mirror (frequency of mirror gazing). Conclusions: Once the patient looks at the mirror, it only lasts about 5 seconds on average. Thus, we confirmed that patients could not concentrate on the illusion during the session and therefore it may have affected the effectiveness of the therapy.

• Physical Therapy Rehabilitation Science
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• v.10 no.1
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• pp.22-31
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• 2021

Objective: This review aims to analyze the effects of electromechanically assisted walking in patients with cerebral palsy(CP). Design: A systematic review and meta-analysis. Methods: We reviewed systematically using the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) checklist guidelines. The inclusion criteria for this study were all CP patients. The intervention was electromechanically assisted walking. The outcome measures included gait parameters, function, spasticity. Studies excluded from this review were excluded from the review if they were non-English languages and if the study was not published as a full report, and if they were not randomized controlled trials (RCTs) designs. The RevMan 5.4 program was used to evaluate and explain the results. The risk of bias was evaluated independently by two reviewers. The quantitative meta-analysis, including mean differences (MD) and associated standard deviations (SD) from baseline and follow-up assessments, were recorded. Results: A total of 634 articles were searched. Two hundred eighty-nine duplicate articles were excluded, and 345 of 634 originals were left for selection. Of these 74 papers, 44 were out of topic, and 19 reported no mean or standard deviation values. And one was a non-experimental study. Finally, ten studies were included. All 10 RCTs of electromechanically assisted walking were analyzed. The meta-analysis showed a significant improvement in gait cycle (95% CI (confidence intervals), 0.09 to 0.19, I2=0%), Gross Motor Function Measure (GMFM) D (95% CI, 3.27 to 13.17, I2=0%) and GMFM E (95% CI, 0.22 to 6.41, I2=0%). Conclusions: Electromechanically assisted training helps in walking in patients with CP.

• Journal of Aerospace System Engineering
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• v.16 no.3
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• pp.63-72
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• 2022

The purpose of this paper was to understand the dynamics of deployment of large mesh antennas, and to provide a numerical method for determining the dynamic stiffness and the driving forces for the design. The deployment structure was numerically modeled using the frame elements. The eigenvalue analysis was demonstrated, with respect to the folded and unfolded configurations of the antenna. A multibody dynamic model was formulated with Kane's equation, and simulated using the pseudo upper triangular decomposition (PUTD) method for resolving the constrained problem. Based on the multibody model, the kinetics of the deployment, the motor driving forces, and the feasibility of the designed deployment structure were investigated.