• Transactions of the Korean Society of Automotive Engineers
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• v.8 no.4
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• pp.186-193
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• 2000

EPS(Electric Power Steering) systems have many advantages over traditional hydraulic power steering systems in space efficiency engine efficiency and environmental compatibility. In this paper an EPS system control logic using a torque map is proposed. The main function of the EPS system is to reduce the steering torque exerted by a driver by assist of an electric motor. Vehcile speed steering torque and steering wheel angle are measured and fed back to the EPS control system where appropriate assist torque is generated to assist the operator's steering effort. Another capability of the EPS system for easy adaptation to different steering feels via simple tuning is demonstrated by the experiments. It will be also verified that the EPS system can also improve damping and return performance of the steering wheel by control of the assist motor.

• Transactions of the Korean Society of Mechanical Engineers
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• v.15 no.2
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• pp.488-496
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• 1991

Dynamic chanracterisitcs and control of a submerged working robot manipulator have been investigated for articulated type robot manipulator with three revoluted joints. A dynamic equation of the manipulator has been derived. The dynamic equation includes not only mass matrix, centrifugal and Coriolis terms and gravity terms but also added mass, buoyant force and drag force terms, which are important terms for underwater motion description. A series of simulations using computed torque method have been performed for the cases of straight and circular trajectory motion controls. The results of this study show that the dynamic characteristics of the submerged working robot manipulator are very different from that of the manipulator which works in air. The influences of added mass, buoyant force and drag force terms to the total required torques have been discussed as distribution ratios to the total required torques.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.11
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• pp.157-163
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• 2019

This study determines the difference in prevalence of anemia and hemoglobin concentration between chronic obstructive pulmonary disease (COPD) and control groups in the elderly. Moreover, this study also examines the prevalence of anemia and hemoglobin concentration according to the severity of COPD in the elderly. Medical records of 8150 participants who answered the 7th National Health and Nutritional Survey conducted in 2016 were reviewed, and a total of 694 participants was included in the analysis. Participants were classified into two groups: COPD and control groups. Laboratory studies on hemoglobin, hematocrit, red blood cell concentration and prevalence of anemia were collected. Subgroup analysis was also conducted according to the severity of COPD. No significant differences were determined for the prevalence of anemia and hemoglobin concentration between both groups. Hemoglobin concentration was significantly higher in the COPD group. Although not statistically significant, there was a tendency for decrease in the prevalence of anemia and increase in the hemoglobin concentration as the severity of COPD increased. Our findings present specific data about the prevalence of anemia and hemoglobin concentration in elderly patients with COPD. Hence, we propose that occurrence of anemia in elderly patients with COPD requires further evaluation of the causes.

• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.12
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• pp.2315-2327
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• 1992

A robot assembly method which uses configuration and force/torque information of tactile sensor system and performs chamferless peg-in-hole tasks is suggested and experimentally studied. When the robot gripes the peg with random orientation, the realignment of the peg to the hole center line is successfully performed with the gripping configuration information of the tactile sensor and the inverse kinematics of the robot. The force/torque information of the tactile sensor makes it possible to control the contacting force between mating parts during hole search stage. The suggested algorithm employs a hybrid position/force control and the experiments show that the algorithm accomplishes well peg-in-hole tasks with permissible small contacting force. The chamferless peg-in-hole tasks with smaller clearance than the robot repeatibility can be excuted without any loss or deformation of mating parts. This study the possibility of precise and chamferless parts mating by robot and tactile sensor system.