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27 results on '"Lee, Suwoong"'

24. Haptic feedback of real soft objects with haptic device using flexible sheet.

Author

Inoue, Kenji, Shimoe, Masanori, and Lee, Suwoong

Abstract

A haptic device using flexible sheet is developed. This device elongates a rubber sheet with four servo motors in parallel. Controlling their motor angles varies softness of the sheet: stretched sheet feels hard, and loose sheet feels soft. Hence a user can feel different softness of virtual objects when he pushes the sheet directly with his finger. We apply this device to haptic feedback of real soft objects. The system consists of the haptic device and a robot with a pressure sensing device. This sensing device is a rubber hemisphere filled with air. The internal pressure is measured when the hemisphere is pressed against an object. First a user pushes the center of the sheet. The movement of the side edge of the sheet is observed with a close-up camera, and the user's pushing pressure on the sheet is estimated. Next the robot pushes a target object so that its pushing pressure on the object, which is measured with the pressure sensing device, may coincide with the user's pushing pressure on the sheet. At the same time, the softness of the object is estimated from the measured pushing pressure on the object and the indentation of the object, which is given by the robot's movement. Then the haptic device controls the motor angles so that the sheet's softness may be equal to the object's softness. The system repeats this process in real time. In this way the user feels the same softness as the real object by pushing the sheet. As an experimental result, the developed haptic device can imitate softness of a real stuffed doll. [ABSTRACT FROM PUBLISHER]

Published
2013
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26. Safety-Function Design for the Control System of a Human-Cooperative Robot Based on Functional Safety of Hardware and Software.

Author

Lee, Suwoong, Yamada, Yoji, Ichikawa, Kazuhiro, Matsumoto, Osamu, Homma, Keiko, and Ono, Eiichi

Abstract

Human-cooperative robots (HCRs) are expected to benefit various fields. Safety functions are essential to the control system of HCRs because their hazardous movements after a system failure may cause serious injuries to operators. Therefore, their reliability must be sufficiently high relative to the estimated risk, and it is important to design a suitable safety function for the control system to match the safety level required for an HCR. We propose a methodology of safety-function design for the control system of an HCR and attempt to effectively combine design approaches for hardware and software of safety-related systems (SRSs) on the basis of the concept of functional safety. This study describes the details of the methodology for an HCR that we adopted as a platform system. First, SRS hardware with a dual-channel voting architecture was designed, and then, functional safety analysis was performed to verify whether the hardware satisfied the required safety integrity level (SIL). Next, SRS software with diverse programming, which is recommended for the required SIL, was designed by utilizing a disturbance observer. Finally, experiments were conducted on the SRS for representative failures and the safety function was verified for the control system, as set by the proposed methodology. [ABSTRACT FROM PUBLISHER]

Published
2014
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27. A Safety Measure for Control Mode Switching of Skill-Assist for Effective Automotive Manufacturing.

Author

Lee, Suwoong, Hara, Susumu, and Yamada, Yoji

Abstract

The objective of our study is to develop a safety measure that ensures smooth control mode switching of an intelligent assist device (IAD)—Skill-Assist for the purpose of effective automotive manufacturing. Smooth switching, i.e., switching without abrupt deceleration, from the hands-off control mode (used for automatic travel) to the hands-on control mode (as typified by a power-assist control mode) is expected to enhance the productivity of IADs. However, the hazardous behaviors, i.e., careless behaviors that disregard an approaching IAD in hands-off control mode might cause collision and serious injuries to a human operator. For safety purposes, we focused on the operator's gesture of reaching for the force sensor of the Skill-Assist. Laser range sensors were employed to recognize the reaching gesture during control mode switching. A reaching gesture recognition algorithm, based on a hidden Markov model, processes characteristic patterns acquired by the laser range sensors, and judges the operator safety. Experimental results suggest that the Skill-Assist to which the proposed safety measure was applied could recognize the reaching gesture of an operator when the control mode was smoothly switched. In an experiment on hazardous behavior, the Skill-Assist could predict that the operator would be unsafe. [ABSTRACT FROM PUBLISHER]

Published
2010
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