• Journal of the Korean Society for Precision Engineering
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• v.30 no.5
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• pp.529-536
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• 2013

Most serious stroke patients have the paralysis on their wrists, and can't use their hands freely. But their wrists can be recovered by rehabilitation exercises. Recently, professional rehabilitation therapeutists help stroke patients exercise their wrists in hospital. But it is difficult for them to rehabilitate their wrists, because the therapeutists are much less than stroke patients in number. Therefore, the wrist twist-exercise rehabilitation robot that can measure the twist force of the patients' wrists is needed and developed. In this paper, the six-axis force/moment sensor was designed appropriately for the robot. As a test result, the interference error of the six-axis force/moment sensor was less than 0.85%. It is thought that the sensor can be used to measure the wrist twist force of the patient.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.21 no.2
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• pp.116-122
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• 2022

This study proposed a method of testing the stability when selecting gears to reduce the weight of a 3-DOF wrist mechanism for a pick-and-place 3-DOF parallel robot with an increased workspace by using an additional straight axis at its top. We performed SolidWorks^® modeling- and ANSYS^®-based structural analysis of a pinion gear, which is most vulnerable to the force from a 3-DOF wrist mechanism, to lighten the robot weight for performing various tasks. When the initial analysis results considerably differed from the theoretical values calculated in advance, we checked and identified the errors in the contact conditions or input values. Ultimately, it is believed that the methodology presented in this paper will help in mitigating errors during analysis and determine the accurate values for a lightweight 3-DOF wrist mechanism for a parallel robot with an expanded workspace.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.18 no.9
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• pp.913-919
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• 2008

Dynamic characteristics of a wrist power transmission of an industrial robot are studied. The wrist power transmission has complex structure characteristics, because it is composed with several shafts and gear system. We used an analytical method to investigate the dynamic characteristics. An analytical model is a rigid model which is composed with masses and springs. Both bearing and gear contact model represent equivalent stiffness springs which are determined by the experiment. In order to investigate the dynamic tendency of the robot wrist power transmission, we simulate the analytical model. There is a dynamic analysis tool which is called the RecurDyn. To verify the analytic results, we experiment a signal analysis which is an overall noise level of the robot. By the parametric study of the element of the robot, we study an improvement method of dynamic characteristics.

• The Journal of Korea Robotics Society
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• v.18 no.1
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• pp.18-28
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• 2023

This study introduces a smart wrist band system with pressure measurements using wrist skin curvature variation due to finger motion. It is easy to wear and take off without pre-adaptation or surgery to use. By analyzing the depth variation of wrist skin curvature during each finger motion, we elaborated the most suitable location of each Force Sensitive Resistor (FSR) to be attached in the wristband with anatomical consideration. A 3D depth camera was used to investigate distinctive wrist locations, responsible for the anatomically de-coupled thumb, index, and middle finger, where the variations of wrist skin curvature appear independently. Then sensors within the wristband were attached correspondingly to measure the pressure change of those points and eventually the finger motion. The smart wrist band was validated for its practicality through two demonstrative applications, i.e., one for a real-time control of prosthetic robot hands and the other for natural human-computer interfacing. And hopefully other futuristic human-related applications would be benefited from the proposed smart wrist band system.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.04a
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• pp.150-155
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• 2008

Dynamic characteristics of a wrist power transmission examine closely with mass property, to present a model which is able to induce the vibration is ultimately the purpose. A robot wrist power transmission for analysis model gets the mass property through the approach to be the experimental. A bearing equivalent stiffness which supports the axis and a gear contact equivalent stiffness are determined by the simplicity analysis model compared the result of the experiment. We calculate the vibration tendency of the robot wrist power transmission by an analysis tool which is called the RecurDyn. We compared it with a signal analysis experiment's which a robot operation happens which is based on the ambient noise.

• Journal of Biomedical Engineering Research
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• v.40 no.3
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• pp.116-124
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• 2019

The rehabilitation training robots for treating the upper limbs of stroke patients were mainly focused on the upper proximal treatment of it, but recently studies of the distal parts of the upper limbs for rehabilitation of the hand is making some progress even though it is still a small number so far. In this paper, we present the hand robot for the rehabilitation training of stroke patients that is the fingertip contact-typed mechanism, and it has also equipped with the wrist rehabilitation unit to be worked like human hand that enables any movements through mutual cooperation by fingers while picking up or grasping objects. The robot that is presented for this purpose supports the movement of fingers with 5-DoF and the wrist with 3-DoF that moves independently, and operates with a structure that allows the joints of the wrist and fingers to be collaborated organically together to each other. Also, hereby the simulation and evaluation test on its robot mechanism are performed to ensure that fingers with 5-DoF and the wrist with 3-DoF of the serial kinematical mechanism are designed to comply with or exceed ROM for ADL.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2013.05a
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• pp.1021-1022
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• 2013

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2013.05a
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• pp.1023-1024
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• 2013

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2013.05a
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• pp.1025-1026
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• 2013

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.5 no.10
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• pp.1751-1768
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• 2011

Falls are one of the most concerned accidents for elderly people and often result in serious physical and psychological consequences. Many researchers have studied fall detection techniques in various domain, however none released to a commercial product satisfying user requirements. We present a systematic modeling and evaluating procedure for best classification performance and then do experiments for comparing the performance of six procedures to get a statistical classifier based wrist-type fall detector to prevent dangerous consequences from falls. Even though the wrist may be the most difficult measurement location on the body to discern a fall event, the proposed feature deduction process and fall classification procedures shows positive results by using data sets of fall and general activity as two classes.