• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.6
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• pp.938-948
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• 2001

In this paper, we present an exoskeletal haptic device named SKK Hand Master. This device is directly driven linkages actuated with small ultrasonic motors. By adopting ultrasonic motors that have advantageous features useful for cybernetic actuators, a compact haptic device containing whole driving packages can be established without additional power transmissions such as tendons. Methods for measuring joint postures and joint torques are developed and a new control strategy called PWM/PS is proposed to overcome intrinsic disadvantages such as hysteresis. Issues regarding design and construction of the device are addressed and several results of experiments for the evaluations of performance are included.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.05a
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• pp.761-762
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• 2012

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2013.05a
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• pp.375-376
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• 2013

• Proceedings of the Korea Society of Design Studies Conference
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• 2005.05a
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• pp.214-215
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• 2005

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.25.4-25
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• 2001

In this paper, a five degree-of-freedom haptic device is proposed. The proposed haptic device has a pen which is suspended by tensioned six strings. Human operator handles the pen. Six DC motors are used as actuators to generate tensions in six strings to make resultant force feedback at the pen to the human operator Six encoders are used for calculating the movement of the pen. A digital controller is used for generate control signals for the suitable tension in the six strings. A current amplifiers is used for amplifying the control signals. Cable-suspended system has advantages of structure simplicity (only with several strings driven by motors without using other tensioning mechanisms), low inertia, and high force-to-weight ratio. Pen-based system has advantages of compactness and ...

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 1998.06b
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• pp.67-72
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• 1998

The paper aims to present a new human-scale haptic advice for virtual environment named Scaleable-SPIDAR (Space Interface Device for Artificial Reality), which can provides different aspects of force feedback sensations, associated mainly with weight, contact and inertia, to both hands within a cave-like space. Tensioned string techniques are used to generate such haptic sensations, while keeping the space transparent and unbulky. The device is scaleable so as to enclose different cave-like working spaces. Scaleable-SPIDAR is coupled with a large screen where a computer generated virtual world is displayed. The used approach is shown to be simple, safe ad sufficiently accurate for human-scale virtual environment.

• Proceedings of the KIEE Conference
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• 2002.07d
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• pp.2510-2512
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• 2002

In this paper, we investigated 2-DOF haptic device and the method of virtual environment modeling for virtual reality. We designed an modified five bar link system to improve the performance. The haptic control system is composed of calculating kinematics and statics, controlling actuator, and describing the virtual environment. Using this system, we realized the virtual spring model and the freely falling ball model.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.11
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• pp.5338-5343
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• 2013

In a haptic system, a virtual wall is modeled as a virtual spring. The larger the stiffness of the virtual spring is, the more improved the reality of the virtual wall is, but the more unstable the haptic system becomes. This paper shows how to increase the stiffness of the virtual spring while the stability of the haptic system is guaranteed and shows the effects of a mass (Md) and a damper (Bd) of a haptic device on the stability when first-order hold method is applied and a virtual wall is modeled as a virtual spring (Kw). The simulation results show the boundary of the virtual spring is proportional to the square root of the mass (Md) and the damper (Bd) while maintaining the stability. The relation among the virtual spring (Kw), the mass (Md) and the damper (Bd) of the haptic device, and sampling time (T) is inferred as $K_w{\leq}{1.611M_d}^{0.50}{B_d}^{0.50}T^{-1.51}$, by using the simulation results. The maximum available stiffness of the virtual spring in first-order hold method is larger than in zero-order hold method. So the reality of the virtual wall can be improved.

• The Journal of Korea Robotics Society
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• v.8 no.3
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• pp.173-178
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• 2013

We present six-degree-of-freedom (6DoF) haptic rendering algorithms using translational ($PD_t$) and generalized penetration depth ($PD_g$). Our rendering algorithm can handle any type of object/object haptic interaction using penalty-based response and makes no assumption about the underlying geometry and topology. Moreover, our rendering algorithm can effectively deal with multiple contacts. Our penetration depth algorithms for $PD_t$ and $PD_g$ are based on a contact-space projection technique combined with iterative, local optimization on the contact-space. We circumvent the local minima problem, imposed by the local optimization, using motion coherence present in the haptic simulation. Our experimental results show that our methods can produce high-fidelity force feedback for general polygonal models consisting of tens of thousands of triangles at near-haptic rates, and are successfully integrated into an off-the-shelf 6DoF haptic device. We also discuss the benefits of using different formulations of penetration depth in the context of 6DoF haptics.

• Journal of Institute of Control, Robotics and Systems
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• v.8 no.5
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• pp.393-400
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• 2002

Teleoperation enables an operator to manipulate remote objects. One of the main goals in teleoperation researches is to provide the operator with the fueling of the telepresence, being present at the remote site. For these purposes, a master robot must be designed as a bilateral control system that can transmit position/force information to a slave robot and feedback the interaction force. A newly proposed impedance algorithm is applied for the control of a haptic interface that was developed as a master robot. With the movements of the haptic interface for position/force commands, impedance parameters are always varying. When the impedance parameters between an operator and the haptic interface and the dynamic model are known precisely, many model based control theories and methods can be used to control the device accurately. However, due to the parameters'variations and the uncertainty of the dynamic model, it is difficult to control haptic interfaces precisely. This paper presents a robust adaptive impedance control algorithm for haptic interfaces.