• Journal of Institute of Control, Robotics and Systems
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• v.9 no.8
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• pp.585-591
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• 2003

A virtual force is generated and fed back to the operator to make the teleoperation more reliable, which reflects the relationship between a slave robot and an uncertain remote environment as a form of an impedance. In general, for the teleoperation, the teleoperated mobile robot takes pictures of the remote environment and sends the visual information back to the operator over the Internet. Because of the limitations of communication bandwidth and narrow view-angles of camera, it is not possible to watch certain regions, for examples, the shadow and curved areas. To overcome this problem, a virtual force is generated according to both the distance between the obstacle and the robot and the approaching velocity of the obstacle w.r.t the collision vector based on the ultrasonic sensor data. This virtual force is transferred back to the master (two degrees of freedom joystick) over the Internet to enable a human operator to estimate the position of obstacle at the remote site. By holding this master, in spite of limited visual information, the operator can feel the spatial sense against the remote environment. It is demonstrated by experiments that this collision vector based haptic reflection improves the performance of teleoperated mobile robot significantly.

• 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.

• Journal of Mechanical Science and Technology
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• v.18 no.7
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• pp.1131-1139
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• 2004

A new impedance controller is proposed for bilateral teleoperation under a time delay. The proposed controller does not need to measure or estimate the time delay in the communication channel using the force loop-back. In designing a stable impedance controller, absolute stability is used as a stability analysis tool, which results in a less conservative controller than the passivity concept. Moreover, in order to remove the conservatism associated with the assumption of infinite port impedances, the boundaries of human and environment impedance are set to finite values. Based on this, this paper proposes a parameter design procedure for stable impedance controllers. The validity of the proposed control scheme is demonstrated by experiments with a 1-dof master/slave system.

• Journal of the Ergonomics Society of Korea
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• v.19 no.2
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• pp.33-45
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• 2000

Present study was performed to compare different types of teleoperation performance measures. A modified Cooper-Harper rating scale and a distance measure were newly introduced and compared to two traditional measures, the error rate and time-to-completion. Participants performed a simulated telerobotic task with varying visual display interfaces. The results of correlation analyses revealed that the modified Cooper-Harper ratings had a close association with the error rate measure. The distance measure also appeared to be a consistent performance measure, which accounted for both the error rate and time-to-completion. A further analysis, however, showed that the effectiveness of each performance measure varied with the level of task difficulty. The results imply that the choice of performance measure should be made based on the task difficulty as well as the particular task being studied. The results revealed here also have implication for performance measures of various display and control systems including aircraft navigation displays and tactical displays.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.9
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• pp.56-62
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• 2004

Recently, necessity and usage of the teleoperation have been increased in various fields from industrial automation to home application. Also, the internet is considered as a strong candidate far the transmission media of signals. However, it has an irregular transmission time delay and causes critical problems such as instability and poor performance. This paper presents a practical internet teleoperation system with a streaming buffer system which makes a variable time delay fixed. Validity of the proposed system is demonstrated by implementing the embedded system on a HILS(hardware in the loop system) which models a two-wheel mobile robot.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.33 no.4
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• pp.283-295
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• 2009

Haptics technology allows one to interact with virtual environments, augmented environments, and real environments providing tactual sensory information. Science and technology of haptics can in general be classified into three groups: machine haptics, computer haptics, and human haptics. This paper surveys the state-of-the-art of haptic control technology for virtual environments and teleoperation (real environments) and then proposes possible future research directions in the following areas: haptic stability control, bilateral teleoperation control, and stability enhancement control.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2007.04a
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• pp.135-138
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• 2007

In this paper, intelligent filtering methodology for masterarm translation signal is proposed. Fidelity and stability are contradicting factors in teleoperation. Human hand trembling filtering is one of the problems in telemanipulation field. During every operation the hand has a certain vibration that can affect the quality of teleoperation, especially in carrying FPD (Flat Panel for Display), nanomanipuation and other precise tasks. It is very important to study the kinesthetic perception of the human and to optimize the teleoperation system accordingly. To cancel out the influence of human's hand vibration the signal from the masterarm should be filtered. One of the feasible solutions is to use an intelligent filter, which is a very flexible instrument. Applying intelligent filtering methodology, we can use some heuristic methods to solve the filtering problem.

• Journal of Institute of Control, Robotics and Systems
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• v.16 no.6
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• pp.553-558
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• 2010

In this paper, we proposed a teleoperation scheme of unmanned grounded vehicle to improve telepresence. Especially, bilateral control architecture for transmitting realistic steering feeling to the remote driver is investigated. System architecture of the teleoperated remote vehicle is introduced with visual, auditory and kinesthetic haptic channel. Several bilateral control architectures are proposed for transmitting remote steering feeling, and subject tests are done to evaluate the performance. Position-force bilateral control architecture with returning torque compensation algorithm shows best performance.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.50 no.6
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• pp.283-294
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• 2001

In this paper, a masterarm for teleoperation of humanoid robot is presented. This masterarm is based human kinematics, which not only mimics human posture/motion completely, but also has wider work range. In addition, by using the distributed controller architecture and electric brake for force reflection, small size and lightweight of the device can be achieved. Some size and lightweight of the device can be achieved. Some important experiments integrated with the humanoid robot, CENTAUR developed by KIST(Korea Institute of Science and Technology), are conducted to evaluate the performance of the proposed masterarm.

• Journal of Institute of Control, Robotics and Systems
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• v.9 no.8
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• pp.600-609
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• 2003

A hybrid stabilization approach involving both Passivity Observer/passivity Controller and wave variables is addressed to stabilize the teleoperation system with time delay. To guarantee the stability of master or slave side, Passivity Observer and Passivity Controller are applied. But Passivity Observer and Passivity Controller technique cannot deal with communication delay and even small communication delay cause the system to be unstable. To cope with this problem, wave variables are additionally employed to have robustness to arbitrary delays. To show the validity of our proposed approach, several computer simulation results are illustrated.