• Industrial Engineering and Management Systems
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• v.8 no.3
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• pp.181-193
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• 2009

This paper presents a framework for controlling mobile multiple robots connected by communication networks. This framework provides novel methods to control coordinated systems using mobile agents. The combination of the mobile agent and mobile multiple robots opens a new horizon of efficient use of mobile robot resources. Instead of physical movement of multiple robots, mobile software agents can migrate from one robot to another so that they can minimize energy consumption in aggregation. The imaginary application is making "carts," such as found in large airports, intelligent. Travelers pick up carts at designated points but leave them arbitrary places. It is a considerable task to re-collect them. It is, therefore, desirable that intelligent carts (intelligent robots) draw themselves together automatically. Simple implementation may be making each cart has a designated assembly point, and when they are free, automatically return to those points. It is easy to implement, but some carts have to travel very long way back to their own assembly point, even though it is located close to some other assembly points. It consumes too much unnecessary energy so that the carts have to have expensive batteries. In order to ameliorate the situation, we employ mobile software agents to locate robots scattered in a field, e.g. an airport, and make them autonomously determine their moving behaviors by using a clustering algorithm based on the Ant Colony Optimization (ACO). ACO is the swarm intelligence-based methods, and a multi-agent system that exploit artificial stigmergy for the solution of combinatorial optimization problems. Preliminary experiments have provided a favorable result. In this paper, we focus on the implementation of the controlling mechanism of the multi-robots using the mobile agents.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1995.04a
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• pp.869-879
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• 1995

The new field of learning control develops controllers that learn to improve their performance at executing a given task, based on experience performing this task. The simplest forms of learning control are based on the same concept as integral control, but operating in the domain of the repetitions of the task. In the previous paper, I had studied the use of such controllers in a decentralized system, such as a robot with the controller for each link acting independently. The basic result of the paper is to show that stability of the learning controllers for all subsystems when the coupling between subsystems is turned off, assures stability of the decentralized learning in the coupled system, provided that the sample time in the digital learning controller is sufficiently short. In this paper, we present two examples. The first illustrates the effect of coupling between subsystems in the system dynamics, and the second studies the application of decentralized learning control to robot problems. The latter example illustrates the application of decentralized learning control to nonlinear systems, and also studies the effect of the coupling between subsystems introduced in the input matrix by the discretization of the system equations. The conclusion is that for sufficiently small learning gain, and sufficiently small sample time, the simple learning control law based on integral control applied to each robot axis will produce zero tracking error in spite o the dynamic coupling in the robot equations. Of course, the results of this paper have much more general application than just to the robotics tracking problem. Convergence in decentralized systems is seen to depend only on the input and output matrices, provided the sample time is suffiently small.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.45 no.4
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• pp.34-40
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• 2008

This paper presents a vision based walking robot control system using hand shape recognition. To recognize hand shapes, the accurate hand boundary needs to be tracked in image obtained from moving camera. For this, we use an active contour model-based tracking approach with mean shift which reduces dependency of the active contour model to location of initial curve. The proposed system is composed of four modules: a hand detector, a hand tracker, a hand shape recognizer and a robot controller. The hand detector detects a skin color region, which has a specific shape, as hand in an image. Then, the hand tracking is performed using an active contour model with mean shift. Thereafter the hand shape recognition is performed using Hue moments. To assess the validity of the proposed system we tested the proposed system to a walking robot, RCB-1. The experimental results show the effectiveness of the proposed system.

• Journal of Korea Multimedia Society
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• v.13 no.5
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• pp.651-662
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• 2010

This paper describes a method to identify objects for autonomous navigation of an outdoor mobile robot. To identify objects, the robot recognizes the object from an image taken by moving robot on outdoor environment. As a beginning, this paper presents the candidates for a segment of region to building of artificial object, sky and trees of natural objects. Then we define their characteristics individually. In the process, we segment the regions of the objects included by preprocessing using multiple features. Multiple features are HSI, line segments, context information, hue co-occurrence matrix, principal components and vanishing point. An analysis of building identifies the geometrical properties of building facet such as wall region, windows and entrance. The building as intersection in vertical and horizontal line segment of vanishing point extracts the mesh. The wall region of building detect by merging the mesh of the neighbor parallelograms that have similar colors. The property estimates the number of story and rooms in the same floors by merging skewed parallelograms of the same color. We accomplish the result of image segmentation using multiple features and the geometrical properties analysis of object through experiments.

• Journal of Institute of Control, Robotics and Systems
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• v.14 no.3
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• pp.284-294
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• 2008

In this paper, we describe an implementation of small mobile robot that can be used at research and application of mobile sensor networking. This robot that will constitute the sensor network, as a platform of multi-robot system for each to be used as sensor node, has to satisfy restrictions in many aspects in order to perform sensing, communication protocol, and application algorithms. First, the platform must be designed with a robust structure and low power consumption since its maintenance after deployment is difficult. Second, it must have flexibility and modularity to be used effectively in any structure so that it can be used in various applications. Third, it must support the technique of wireless network for ubiquitous computing environment. At last, to let many nodes be scattered, it must be cost-effective and small. Considering the above restrictions of the mobile platform for sensor network, we designed and implemented robots control the current of actuator by using additional circuit for power efficiency. And we chose MSP430 as MCU, CC2420 as RF transceiver, and etc, that have the strength in the aspect of power. For flexibility and modularity, the platform has expansion ports. The results of experiments are described to show that this robot can act as sensor node by RF communication process with Zigbee standard protocol, execute the navigation process with simple obstacle avoidance and the moving action with RSSI(Received Signal Strength Indicator), operate at low-power, and be made with approx. $100.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• v.9 no.2
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• pp.204-207
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• 2005

Until present, most studies about energy efficiency of quadruped walking robot are mathematical modelings, dynamic analysis or simulation consumption energy per period by basic efficiency evaluate in this paper, a quadruped walking robot Titan-VIII is used for walking experience. The total moving length is about 2[m]. The stride length is 0.1, 0.2, 0.3, walking period is changed by 1.0, 1.5, 2.0, 3.0[sec] per each stride length. So consumption energy of 12 cases are measured. The energy efficiency of quadruped walking robot was analyzed by data that is saved by an experiment.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.36 no.9
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• pp.1017-1026
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• 2012

In this study, an exoskeleton-type robot is developed to assist frozen shoulder rehabilitation in a systematic and efficient manner for humans. The developed robot has two main features. The first is a structural feature: this robot was designed to rehabilitate both shoulders of a patient, and the three axes of the shoulder meet at one point to generate human-like ball joint motions. The second is a functional feature that is divided into two rehabilitation modes: the first mode is a joint rehabilitation mode that helps to recover the shoulder's original range of motion by moving the patient's shoulder according to patterns obtained by motion capture, and the second mode is a muscle rehabilitation mode that strengthens the shoulder muscles by suitably resisting the patient's motion. Through these two modes, frozen shoulder rehabilitation can be performed systematically according to the patient's condition. The development procedure is described in detail.

• Journal of IKEEE
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• v.22 no.4
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• pp.922-932
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• 2018

Radial distance sensors are widely used for surveying and autonomous navigation. It is necessary to train the operation principle of these sensors and how to apply them. Although commercialization of radial distance sensor continues to be cost-effective through lower performance, but it is still expensive for educational purposes. In this paper, we propose a distance sensor module with object tracking using radial array of low cost phototransistor which can be used for educational robot. The proposed method is able to detect the position of a fast moving object immediately by arranging the phototransistor in the range of 180 degrees and improve the sensing angle range and track the object by the sensor rotation using the servo motor. The scan speed of the proposed sensor is 50~200 times faster than the commercial distance sensor, thus it can be applied to a high performance educational mobile robot with 1ms control loop.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.6
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• pp.785-791
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• 2021

In this paper, we propose a methodology for estimating the optimal traversable destination from the location-based information of the object recognized by the mobile robot to perform the object delivery service. The location estimation process is to apply the generalized Voronoi graph to the grid map to create an initial topology map composed of nodes and links, recognize objects and extract location data using RGB-D sensors, and collect the shape and distance information of obstacles. Then, by applying the hybrid approach that combines the center of gravity and thinning method, the optimal moving position for the service robot to perform the task of grabbing is estimated. And then, the optimal node information for the robot's work destination is updated by comparing the geometric distance between the estimated position and the existing node according to the node update rule.

• Journal of the Korean Institute of Intelligent Systems
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• v.21 no.1
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• pp.36-41
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• 2011

Configuration space(C-space) including configuration obstacle(C-obstacle) is one of the most important concepts in mobile robot path planning. Using C-space and C-obstacles, the robot with different shapes and moving mechanisms can be considered as a point in the C-space. And, as a result, the collision-free path for the robot can be easily achieved. To make C-space including C-obstacle, many researchers used circular approximation method for the efficient caluculation time. This method can help us to save our time by approximating the shape of a robot as the minimum sized circle which can cover all the area of robot. But, by using the circle larger than the robot, more space are considered as the part of robot and, as a result, some obstacles which are very near each other may be considered as a combined one obstacle. To solve this problem, multi-level configuration space is proposed by this paper. This multi-level method also use the circular approximation method as the initial step. But, after finding the initial path, it will check how many obstacles are combined. And then, for each combined obstacle, more accurate C-space generation will be continued. To check the efficiency of the proposed algorithm, time for c-space generation are compared with the well-known accurate C-space generation method using various types of robot shape.