• Journal of Institute of Control, Robotics and Systems
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• v.20 no.11
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• pp.1153-1163
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• 2014

An efficient 3D SLAM (Simultaneous Localization and Map Building) method is developed for urban building environments using a tilted 2D LRF (Laser Range Finder), in which a 3D map is composed of perpendicular/horizontal planar polygons. While the mobile robot is moving, from the LRF scan distance data in each scan period, line segments on the scan plane are successively extracted. We propose an "expected line segment" concept for matching: to add each of these scan line segments to the most suitable line segment group for each perpendicular/horizontal planar polygon in the 3D map. After performing 2D localization to determine the pose of the mobile robot, we construct updated perpendicular/horizontal infinite planes and then determine their boundaries to obtain the perpendicular/horizontal planar polygons which constitute our 3D map. Finally, the proposed SLAM algorithm is validated via extensive simulations and experiments.

• Journal of Hydrogen and New Energy
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• v.28 no.1
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• pp.70-76
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• 2017

To synthesize copper nanoparticle a thermal decomposition was adopted. And to solve the problem of surface oxidation of the synthesized copper powder an electroless Ag plating method was used. The size and shape of synthesized Cu nanoparticle were affected by the size of copper oxalate used as a precursor, reaction solvent, reaction temperature and amount of reducing agent. Especially reaction solvent is dominant factor to control shape of Cu nano-particle which can have the shapes of sphere, polygon and rod. In case of glycerol, it produced spherical shape of about 500 nm in size. Poly ethylene produced uniform polygonal shape in about 700 nm and ethylene glycol produced both of polygon and rod having size range between 500 and 1500 nm. The silver coated copper powder showed a high electrical conductivity.

• 제어로봇시스템학회:학술대회논문집
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• 1991.10b
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• pp.1601-1606
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• 1991

We present an algorithm to approximate the Voronoi diagrams of 2D objects bounded by algebraic curves. Since the bisector curve for two algebraic curves of degree d can have a very high algebraic degree of 2 * d$^{4}$, it is very difficult to compute the exact algebraic curve equation of Voronoi edge. Thus, we suggest a simple polygonal approximation method. We first approximate each object by a simple polygon and compute a simplified polygonal Voronoi diagram for the approximating polygons. Finally, we approximate each monotone polygonal chain of Voronoi edges with Bezier cubic curve segments using least-square curve fitting.

• 제어로봇시스템학회:학술대회논문집
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• 1991.10a
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• pp.730-735
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• 1991

In this paper, a graphics system supporting PHIGS and PHIGS+ is suggested and its hardware structure and software are described. The developed graphics system is a multi-processing system that uses 6 i860 RISC CPU's and supports PHIGS and PHIGS+ language in a hardware level. The developed system under tested is able to draw 160, 000 3-D polygones in one second when each polygon has 100 pixels and is shaded with Gouraud shading.

• Communications of the Korean Mathematical Society
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• v.22 no.4
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• pp.641-648
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• 2007

In this paper, we present the exact Hausdorff distance between the offset curve of quadratic $B\'{e}zier$ curve and its quadratic $GC^1$ approximation. To illustrate the formula for the Hausdorff distance, we give an example of the quadratic $GC^1$ approximation of the offset curve of a quadratic $B\'{e}zier$ curve.

• International Journal of CAD/CAM
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• v.5 no.1
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• pp.29-38
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• 2005

A non-uniform 3-point ternary interpolatory subdivision scheme with variable subdivision weights is introduced. Its support is computed. The $C^0$ and $C^1$ convergence analysis are presented. To elevate its controllability, a modified edition is proposed. For every initial control point on the initial control polygon a shape weight is introduced. These weights can be used to control the shape of the corresponding subdivision curve easily and purposefully. The role of the initial shape weight is analyzed theoretically. The application of the presented schemes in designing smooth interpolatory curves and surfaces is discussed. In contrast to most conventional interpolatory subdivision scheme, the presented subdivision schemes have better locality. They can be used to generate $C^0$ or $C^1$ interpolatory subdivision curves or surfaces and control their shapes wholly or locally.

• Journal of Institute of Control, Robotics and Systems
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• v.6 no.11
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• pp.1003-1012
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• 2000

When a robot hand grasp an object, the number of ways to grasp it stably are infinite and thus an optimal grasp planning is needed to find the optimal grasp points for satisfying the objective of the given task. In this paper, we first define some grasp indices to evaluate the quality of each feasible grasp and then a weighted composite grasp index by combining all of the grasp indices is also defined. Next, we propose a method to find the optimal grasp points of the given object by comparing the defined weighted composite grasp index for each feasible grasp points. By simulation results, we show the effectiveness of the proposed optimal grasp planning method and also discuss the trend of each grasp index as the grasp polygon.

• Journal of Institute of Control, Robotics and Systems
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• v.19 no.4
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• pp.349-356
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• 2013

This paper presents formation control based on potential functions for unicycle robots. The unicycle robots move to formation position which is made from a reference point and neighboring robots. In the framework, a local minimum case occurred by combination of potential repulsed from neighboring robots and potential attracted from a formation line is presented, in which the robot escapes from a local minimum using a virtual escape point after recognizing trapped situation. As well, in the paper, potential functions are designed to keep the same distance between neighboring robots on a formation line, i.e. the relative distance between neighboring robots on a formation line is controlled by a potential function parameter. The simulation results show that the proposed approach can effectively construct straight line, V, and polygon formation for multiple robots.

• Journal of Power Electronics
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• v.16 no.2
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• pp.572-583
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• 2016

In view of the speed control characteristics of induction traction motors and the problems of direct torque control (DTC) algorithms in current applications, this paper presents a DTC algorithm characterized by a symmetrical polygon flux control and a closed loop power control in the constant-torque base speed region and constant-power field-weakening region of induction traction motors. This algorithm only needs to add a stator flux control algorithm to the traditional DTC structures. This has the benefit of simplicity, while maintaining the features of traditional algorithms such as a rapid dynamic response, uncomplicated control circuit, reduced dependence on motor parameters, etc. In addition, it obtains a smoother flux trajectory that is conducive to improvement of the harmonic elimination capability, the switching frequency utilization as well as the torque and power performance in the field-weakening region. The effectiveness and feasibility of this DTC algorithm are demonstrated by both theoretical analysis and experimental results.

• Journal of Digital Contents Society
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• v.5 no.4
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• pp.269-274
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• 2004

The field based morping requires the user to set most of the control lines manually which require much time and skill to get satisfactory results. This tjesis proposes a method to acquire semi-automation of image morphing through first acquiring shape information from the source image and the target image, than after the user manually designates the least amount of a pair of feature points, these are used as standards for polygon based vertex to set the appropriate control line to the source image and target image, and then using the ratio of control line lengths and space. Using the proposed method the user can reduce the time setting the control line and unskilled persons can get natural image morphing results while desingnating the least amount of control line.