• Journal of the Korean Institute of Intelligent Systems
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• v.18 no.6
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• pp.746-753
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• 2008

In this paper, we introduce the improved control method are communicated between a master and a slave robot in the teleoperation systems. When the master and slave robots are located in different places, time delay is unavoidable under the network environment and it is well known that the system can become unstable when even a small time delay exists in the communication channel. The time delay may cause instability in teleoperation systems especially if those systems include haptic feedback. This paper presents a control scheme based on the estimator with virtual master model in teleoperation systems over the network. As the behavior of virtual model is tracking the one of master model, the operator can control real master robot by manipulating the virtual robot. And LQG/LTR scheme was adopted for the compensation of un-modeled dynamics. The approach is based on virtual master model, which has been implemented on a robot over the network. Its performance is verified by the computer simulation and the experiment.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.39 no.2
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• pp.137-142
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• 2015

Teleoperation of a robot arm working in hazardous environments has been studied in the field of defense and security. A master system is an essential part that plays an important role in the teleoperation. We developed a master system, which is an essential part in the teleoperation, so that it can operate the slave robot arm intuitively and has excellent mobility and portability compared to conventional master systems. The master system adopted a Stewart platform to minimize the size and weight, and the legs of the Stewart platform are composed of wires to improve the operation range of the system. The experimental validation of the developed master system is conducted with a commercial IMU, and the experimental results show that the proposed master system can perform reliable and dexterous teleoperation.

• Journal of Advanced Marine Engineering and Technology
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• v.41 no.1
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• pp.56-61
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• 2017

This paper presents a data prediction method and its application to haptic-based teleoperation systems. In general, time delays inevitably occur during data transmission in a network environment, which degrades the overall performance of haptic-based teleoperation systems. To address this situation, this paper proposes an autoregressive moving average (ARMA) model-based data prediction algorithm for estimating model parameters and predicting future data recursively in real time. The proposed method was applied to haptic data captured every 5 ms while bilateral haptic interaction was carried out by two users with an object in a virtual space. The results showed that the prediction performance of the proposed method had an error of less than 1 ms when predicting position-level data 100 ms ahead.

• 한국HCI학회:학술대회논문집
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• 2008.02c
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• pp.19-24
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• 2008

This paper presents a physically-based haptic rendering algorithm for a deformable object based on visual information about the intervention between a tool and a real object in a remote place. The physically-based model of a deformable object is created from the mechanical properties of the object and the captured image obtained with a CCD camera. When a slave system exerts manipulation tasks on a deformable object, the reaction force for haptic rendering is computed using boundary element method. Snakes algorithm is used to obtain the geometry information of a deformable object. The proposed haptic rendering algorithm can provide haptic feedback to a user without using a force transducer in a teleoperation system.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.5
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• pp.891-898
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• 2001

This paper develops a master manipulator which can reflect a force from a slave manipulator effectively. It many have a big workspace, can represent a human operators manipulation perfectly, and is composed of a position control part, an orientation control part and an end effector control part. This paper also develops a graphic simulator using the Visual C++ and OpenGL in the Window operating system. It can be used to make a virtual slave manipulator and set a virtual working environment, and provide a visual information from a desired view point. A virtual teleoperation system is developed by connecting the developed master manipulator to the graphic simulator using an interfacing hardware bilaterally. It is used for performing a virtual object exploration experiment. In the experiment, two virtual objects are used. They are virtual wall and virtual hexahedron which have 0.7N/mm and 2.2 N/mm stiffness respectively. The experiments are performed under six different working conditions. The experiment results will show the effectiveness of the reflected force from the slave manipulator for improving the efficiency and stability of the teleoperation task.

• The Journal of the Korea Contents Association
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• v.18 no.7
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• pp.322-329
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• 2018

Teleoperation is defined with a master device that gives control command and a slave robot in a remote site. In this field, it is common that a human operator executes and experiences teleoperation with a virtual slave, and preliminary learns dynamic characteristic and network environment from both agents. Generally, a virtual slave has neglected forward dynamics and its kinematic model has been implemented in computer graphics. This makes a operator to experience actual feelings. This paper proposes a dynamic teleoperation model in which a robotic forward model is applied. Also, a novel compensation method is proposed to reduce the numerical error problems in forward dynamics caused by low control sampling rate. Finally, its results will be compared to the teleoperation in an actual environment.

• The Transactions of the Korean Institute of Power Electronics
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• v.5 no.1
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• pp.63-71
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• 2000

원격조정 시스템에서 힘정보는 중요하다. 그러나 특수 응용 분야에 적합한 크기와 측정의 정확성을 가지는 힘 센서의 적용은 매우 어렵다. 더욱이 힘 정보의 전송으로 인한 시간지연으로 시스템은 불안정 되기 쉽다. 본 논문은 가상환경을 이용한 원격조정 시스템을 제안하였다. 시스템은 그래픽 시뮬레이션 처리부, 슬레이브 제어부 그리고 역감 제시부로 구성되어진다. 슬레이브 암이 작업물체와 접촉작업을 할 때 역감은 가상환경에서 계산되어지므로 힘 선세와 시간지연으로 발생되는 문제점을 해결 할 수 있다. 제안된 시스템으로 접촉작업에 대한 힘 제시 원격조정을 수행하였고, 실험결과를 통해서 안정된 접촉작업을 확인하였다.

• 한국HCI학회:학술대회논문집
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• 2009.02a
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• pp.45-51
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• 2009

In this paper, a transparency analysis and network-adaptive transport scheme are proposed in order to improve transparency of EBA-based force-reflecting teleoperation. EBA guarantees stability of force-reflecting teleoperation over network delay and loss but has limitation that it cannot overcome transparency deterioration of haptic interactions. The proposed transparency analysis quantifies the force feedback distortion caused by network delay and loss. Based on the analysis, the proposed haptic data synchronization and transmission rate control schemes adapt synchronization delay and transmission rate to current network state for more transparent haptic interaction. Through Matlab/Simulink simulations, it is confirmed that the proposed analysis provides an acceptable quantification method about haptic interaction quality and that the proposed haptic data transport scheme effectively improves haptic interaction quality with respect to network delays and losses.

• Proceedings of the KSME Conference
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• 2001.06b
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• pp.158-163
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• 2001

Operators suffer much difficulty in manipulating micro/nano-sized objects without the assistance of human interfaces, due to the scaling effects in micro/nano world. This paper presents a micro manipulation system based on the teleoperation techniques which enables the operators to manipulate the objects with ease by transferring both human motion and manipulation skill to a micromanipulator. An experimental setup consisting of a micromanipulator operated under stereo-microscope with the help of intelligent user interface provides a tool that can be used to visualize and manipulate micro-sized 3D objects in a controlled manner. The key features of a micro manipulation system and control strategies using teleoperation techniques for handling micro objects are presented. Experimental results demonstrate the feasibility of this system in precisely controlling trapping and manipulation of micro objects based on teleoperation techniques.

• Proceedings of the KIEE Conference
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• 2004.07d
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• pp.2471-2473
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• 2004

원격조작시템은 일반적으로 주로봇, 종로봇과 이들을 연결하는 통신채널로 구성되는데, 통신채널에는 반드시 시간 지연이 존재하고 이는 전체 시스템을 불안정하게 만드는 가장 큰 요인으로 알려져 있다. 시간지연으로 인한 불안정성 문제를 해결하기 위한 연구가 활발히 진행되어 왔는데, 최근에는 웨이브변수를 적용한 원격조작시스템이 많이 사용되고 있다. 웨이브변수를 적용하면 통신채널에 시간지연이 존재하더라도 수동성 관점에서 안정성을 보장할 수 있고, 다른 제어방법에 비하여 구조가 간단하기 때문에 구현하기가, 용이한 장점이 있으나, 특성 임피던스에 따른 성능 변화를 해석한 연구는 없었다. 따라서, 본 논문에서는 웨이브변수를 도입한 원격조작시스템에 대하여 특성 임피던스에 따른 성능을 투명성의 관점에서 해석하고자 한다. 또한, 시간 지연이 존재하는 원격조작시스템에 웨이브 변수를 적용한 실험을 통하여 시간지연 시스템에 대한 웨이브 변수의 강인성을 보이고자 한다.