• Journal of Institute of Control, Robotics and Systems
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• v.9 no.10
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• pp.789-797
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• 2003

An implementation scheme and some improvements are proposed to adopt public-licensed operating system, Linux and de-facto world-wide network standard, TCP/IP into the field of behavior-based autonomous mobile robots. To demonstrate the needs of scheme and the improvement, an analysis is performed on a server/client communication problem with real time Linux previously proposed, and another analysis is also performed on interactions among TCP/IP communications and the performance of Linux system using them. Implementation of behavior-based control architecture on real time Linux is proposed firstly. Revised task-scheduling schemes are proposed that can enhance the performance of server/client communication among local tasks on a Linux platform. A new method of TCP/IP packet flow handling is proposed that prioritizes TCP/IP software interrupts with aperiodic server mechanism as well. To evaluate the implementation scheme and the proposed improvements, performance enhancements are shown through some simulations.

• Journal of Institute of Control, Robotics and Systems
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• v.5 no.4
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• pp.446-453
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• 1999

An athlete motion during weightlifting is analyzed based on robotic manipulability, which shows dexterities by changing the position and orientation of the end-effector of robot manipulators arbitrary or along a specified direction. The athlete body is modeled as a highly redundant robot manipulator. The motion of weightlifting is analyzed based on the selected model with a power manipulability. Power manipulability and its geometric characteristics are derived by combining kinematic manipulability and dynamic manipulability. Also, manipulability-based optimal trajectory of weightlifter for given body structure of weightlifter derived through genetic algorithm.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.1650-1654
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• 2004

This paper presents how it is effective to use many features for improving the speed and the accuracy of the visual servo systems. Some rank conditions which relate the image Jacobian and the control performance are derived. It is also proven that the accuracy is improved by increasing the number of features. Effectiveness of the redundant features is evaluated by the smallest singular value of the image Jacobian which is closely related to the accuracy with respect to the world coordinate system. Usefulness of the redundant features is verified by the real time experiments on a Dual-Arm Robot manipulator made in Samsung Electronic Co. Ltd.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.1424-1429
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• 2004

In this paper a mathematical framework for deriving acceleration bounds from given joint torque limits of multiple cooperating robots are described. Especially when the different frictional contacts for every contact are assumed and the torque limits are given in 2-norm sense, we show that the resultant geometrical configuration for the acceleration is composed of corresponding parts of ellipsoids. Since the frictional forces at the contacts are proportional to the normal squeezing forces, the key points of the work includes how to determine internal forces exerted by each robot in order not to cause slip at the contacts while the object is carried by external forces. A set of examples composed of two robot systems are shown with point-contact-with-friction model and insufficient or proper degree of freedom robots.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.778-782
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• 2003

This paper presents how it is effective to use many features for improving the speed and the accuracy of the visual servo systems. Some rank conditions which relate the image Jacobian and the control performance are derived. It is also proven that the accuracy is improved by increasing the number of features. Effectiveness of the redundant features is evaluated by the smallest singular value of the image Jacobian which is closely related to the accuracy with respect to the world coordinate system. Usefulness of the redundant features is verified by the real time experiments on a Dual-Arm Robot manipulator made in Samsung Electronic Co. Ltd.

• Journal of Institute of Control, Robotics and Systems
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• v.21 no.12
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• pp.1185-1192
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• 2015

In this paper, a study of advanced sound source localization is conducted by eliminating the noise of the sound source using the discrete wavelet transform. And experiments are conducted to evaluate the performance of the proposed system that the mobile robot follows sound source stably. In addition, we compare the position estimation performance by applying a discrete wavelet transform to improve the reliability of the sound signal. The experimental results reveal that the de-nosing filter which removes the noise component in sound source can make the performance of position estimation more precisely and help the mobile robot distinguish the objective sound source clearly.

• International Journal of Control, Automation, and Systems
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• v.5 no.6
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• pp.718-724
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• 2007

We extend the application of an adaptive controller previously introduced in the literature under the assumption that no actuator dynamics exists to the case when the dynamics of the brushed DC-motors used as actuators is not neglected. Convergence to the desired positions is ensured without requiring any feedback to cope with the additional electric dynamics. The proposed control scheme does not require the exact knowledge of neither robot nor actuator parameters to select controller gains.

• Journal of Institute of Control, Robotics and Systems
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• v.17 no.7
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• pp.668-673
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• 2011

This paper presents design and control of a wheelchair robot for handicapped or elderly persons. Novel multi-functional design concepts are introduced. The first function is to balance the chair always parallel to the flat ground so that the driver feels comfortable when he/she drives on the slope. The second function is to help the driver to stand up by pushing the chair so that the driver can get out from the chair with ease. The third design is to make it foldable for easy carrying for automobiles. The last function is an immediate stop and start protection. Experimental studies are conducted to demonstrate the feasibility and functionality of each mechanical design.

• Journal of Institute of Control, Robotics and Systems
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• v.15 no.3
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• pp.306-314
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• 2009

The pelvis platform is the mechanical part which accomplishes the activities of diminishing the disturbances from the lower body and maintaining a balanced posture. When a biped robot walks, a lot of disturbances and irregular vibrations are generated and transmitted to the upper body. As there are some important machines and instruments in the upper body or head such as CPU, controller units, vision system, etc., the upper part should be isolated from disturbances or vibrations to functions properly and finally to improve the biped stability. This platform has 3 rotational degrees of freedom and is able to maintain balanced level by feedback control system. Some sensors are fused for more accurate estimation and the control system which integrates synchronization and active filtering is simulated on the virtual environment.

• Journal of Institute of Control, Robotics and Systems
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• v.15 no.6
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• pp.604-611
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• 2009

Modular snake-like robots are robust for failure and have flexible locomotion for environments, but are difficult to control. Various phase and evolutionary approaches for modular robots have been studied for many years, but there are few comparisons among these methods. In this paper, Phase, GAps, GA and GP approaches are implemented and compared for flat, stairs, and slope environments. In addition, simulations of the locomotion evolution for modular snake-like robot are executed in Webots environments.