• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.21 no.7
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• pp.615-621
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• 2011

There are hundreds of thousands call center workers wearing acoustic device. However, researches and noise exposure measurements on the noise transmitted from acoustic devices have seldom been performed due to the difficulty of measurement and to the absence of the measuring method in Korea. The aim of this study is to set up management measures to protect hearing loss on the call operator by acquiring measurement data of noise transmitted from the headset. Noise exposure measurements of 17 operators were performed in 7 call centers and head and Torso simulator method in compliance with the ISO standard 11904-2 was used for the measurement of noise transmitted from the headset. Sound pressure levels(SPL) transmitted from the headset were 73.2~86 dB(A). The operator exposed to the highest SPL set up his volume control at 9 which was the highest volume level. The volume control level, adjustable from 1 to 9, could be identified 12 out of 17 operators and the range of volume levels was 4.5~9. As a result of pearson correlation analysis, the correlation between volume level and SPL transmitted from the headset showed high relation as significance at the 0.672 level(p<0.05). To protect hearing loss of call center operators, it is more practical and effective measure to limit the volume level below the noise exposure level, i.e. 85 dB(A), rather than to carry out noise monitoring considering cost-effective aspect.

• The Journal of Korea Robotics Society
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• v.14 no.3
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• pp.203-210
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• 2019

This paper proposes a hand-controller mechanism for manually controlled endoscopic surgical instruments. A wire-driven mechanism is typically adapted for endoscopic surgical tools because motors cannot be embedded to the joints due to the size limitation. The wire-driven mechanism requires length control of wires that are pulled and released according to the desired joint angle. It is difficult for the operator to control individual wire lengths intuitively. The hand-controller mechanism should be able to control the wires easily without complex processes. For this purpose, we propose a mechanism that can control the wire lengths with a simple mechanical structure and its optimal design method using genetic algorithm. We show the simulation and experimental results to confirm the proposed mechanism and design methods are useful for the manually controlled endoscopic surgical instrument.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.26 no.11
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• pp.1488-1495
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• 2002

The response time represents how fast a system responds to a given disturbance at the system boundary. Flow restricting devices for controlling transients can result in a decrease in the peakm pressure, but may change response time. Response lag in a hydraulic system leads to inefficient working cycle and operator discomfort. The experiments were conducted in order to get information on the parameters which exert appreciable influence on the response time. The experimental apparatu including a hydraulic actuator, orifice and a hydraulic pump was an idealization of a bucket hydraulic shifting system. Experimental results show that the response time depends on operating pressure and flow rate. The effects of orifice type and size on the response time are quantified.

• The Journal of Korea Robotics Society
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• v.13 no.4
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• pp.248-255
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• 2018

In this paper, a design for a vehicle body of an armored robot for complex disasters is described. The proposed design considers various requirements in complex disaster situations. Fire, explosion, and poisonous gas may occur simultaneously under those sites. Therefore, the armored robot needs a vehicle body that can protect people from falling objects, high temperature, and poisonous gas. In addition, it should provide intuitive control devices and realistic surrounding views to help the operator respond to emergent situations. To fulfill these requirements of the vehicle body, firstly, the frame was designed to withstand the impact of falling objects. Secondly, the positive pressure device and the cooling device were applied. Thirdly, a panoramic view was implemented that enables real-time observation of surroundings through a number of image sensors. Finally, the cockpit in the vehicle body was designed focused on the manipulability of the armored robot in disaster sites.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.140.4-140
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• 2001

This paper presents the duplex controller operated as master slave for Self Excited Static Type excitation system and the results of operation for duplex digital excitation system. Software is made up duplex multi-tasking control algorithm which is based on VxWorks(real-time OS), preprocessing algorithm for input-output signal, BSP & Device Driver for interfacing hardware and software, and OIS(Operator Interface Station) program, HMI S/W. Master controller and slave controller intercommunicate dominant data to minimize bump when controller switchover from master to slave occurs. Communication between master controller and slave controller is duplicated and communication between OIS and controller is duplicated. Hardware is made up VMEBUS based controller which is designed with PPC & I/O board ...

• Transactions on Control, Automation and Systems Engineering
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• v.3 no.4
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• pp.236-241
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• 2001

Teach pendant is the most widely used means of robot teaching at present. Despite the difficulties of using the motion command buttons on the teach pendant, it is an economical, robust, and effective device for robot teaching task. This paper presents the development of a force/moment direction sensor named COSMO that can improve the teach pendant based robot teaching. Robot teaching experiment of a six axis commercial robot using the sensor is described where operator holds the sensor with a hand, and move the robot by pushing, pulling, and twisting the sensor in the direction of the desired motion. No prior knowledge of the coordinate system is required. The function of the COSMO sensor is to detect the presence f force and moment along the principal axes of the sensor coordinate system. The transducer used in the sensor is micro-switch, and this intuitive robot teaching can be implemented at a very low cost.

• Journal of Institute of Control, Robotics and Systems
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• v.13 no.1
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• pp.33-38
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• 2007

In this paper, hardware implementation of interface and control between two robots, the master and the slave robot, are designed. The master robot is the motion capturing device that captures motions of the human operator who wears it. The slave robot is the corresponding humanoid robot arms. Captured motions from the master robot are transferred to the slave robot to follow after the master. All hardware designs such as PID controllers, communications between the master robot, encoder counters, and PWM generators are embedded on a single FPGA chip. Experimental studies are conducted to demonstrate the performance of the FPGA controller design.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.28 no.3
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• pp.89-94
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• 2016

In this experimental study, the effects of top clearance on the performance of automotive a/c compressor were studied. Top clearance measuring device was also developed to ensure the reliability using vacuum conditions to secure constant control of top clearance without external environmental influence. Our results revealed that the improvements in compressor performance according to different top clearance values using the same compressor and same operator were about 4.12% at 800 rpm and about 7.8% at 2,000 rpm in 0.243~0.252 mm of top clearance compared to 0.431~0.456 mm of top clearance. To confirm the consistency in measuring top clearance affecting compressor performance, the top clearance measuring device was developed in this study using a vacuum pump. After performing reliable tests repeatedly, the distribution of measuring values under this device was within 0.99~1.83%, indicating that the constant test data in compressor performance was not affected by any other external environment.

• Journal of Drive and Control
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• v.17 no.4
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• pp.31-37
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• 2020

We are concerned with the dual-arm manipulation for disaster-responding special-purpose machinery. This paper presents a control strategy for performing complex work in an irregular environment, the control algorithm, the hydraulic circuit, and the master devices. The occurrence of collapse accidents at disaster sites such as natural disasters and building collapses is increasing, which is emerging as a social problem. In particular, for the initial response, various tasks must be performed in an irregular environment. The Marionette algorithm for intuitive control of 'as if the operator's arm is moving' was presented as a control strategy for dual-arm manipulators with attachments and the prototype. Next, the hydraulic circuit, control system, and wearable-type master device presented to implement the Marionette algorithm were explained and verified through an experiment in which rebar-cutting, drum-lifting, and lifting a bottle with one arm and pouring the water into the bucket with the other arm were tested.

• Journal of the Korean Society of Safety
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• v.25 no.6
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• pp.40-46
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• 2010

To protect press operator from the after-reach hazard, current Ministry of Labor Notification(MOLN) requires the use of a formula for calculating the safe distance away from the point of operation for locating press protective devices, Two Hand Control Devices(THCD) and Active Opto-Electronic Protective Devices(AOPD), on a power press. This formula is based on a same hand speed constant of 160cm/s. While EN standards use different hand speed constant for THCD and AOPD respectively. The objective of this study is to compare two guidelines on the hand speed constant published by MOLN and EN 692, also to propose a proper hand speed constant and validate it experimentally. As a experimental result, it could be known that hand speed constant of Ministry of Labor Notification should be improved as that of EN standards.