• Korean Journal of Computational Design and Engineering
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• v.15 no.2
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• pp.106-114
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• 2010

The swept volume, the region of a moving object, is applied in many fields such as valid paths for motions of tools, visualization in robot paths and interference tests for parts assembling or disjointing. The shape of a swept volume depends on an generators computed with normal vectors of an object and velocity vectors of a motion. Although free-from surfaces are widely used to represent geometric models in CAD, computing the generators for a free-form object is a formidable task. Previous approaches exploit the closed form expressions of generators but limited to planer or quadric faces. In this paper, we propose the algorithm to compute swept volumes generated by free-form objects in screw motions. For the algorithm a tracing method is applied to the computation of generators. It considers curvatures of surfaces of an object to increase the computational accuracy. We implemented our algorithm in the CATIA V.5 environment to test the validity of our algorithm and to generate examples.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.1909-1914
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• 2004

Passive velocity field control (PVFC) was previously developed for fully mechanical systems, in which the motion task was specified behaviorally in terms of a velocity field, and the closed-loop was passive with respect to a supply rate given by the environment input. However the PVFC was only applied to a single manipulator, the proposed control law was derived geometrically, and the geometric and robustness properties of the closed-loop system were also analyzed. In this paper, we propose a method to apply a decentralized control algorithm to cooperative 3-wheeled mobile robots whose subsystem is under nonholonomic constraints and which convey a common rigid object in a horizontal plain. Moreover it is shown that multiple robot systems ensure stability and the velocities of augmented systems convergence to a scaled multiple of each desired velocity field for cooperative mobile robot systems.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.1093-1098
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• 2003

In this paper, a practical methodology of hand-manipulator motion coordination for indoor service robot is introduced. This paper describes the procedures of opening door performed by service robot as a noticeable example of motion coordination. This paper presents well-structured framework for hand-manipulator motion coordination, which includes intelligent sensor data interpretation, object shape estimation, optimal grasping, on-line motion planning and behavior-based task execution. This proposed approach is focused on how to integrate the respective functions in harmony and enable the robot to complete its operation under the limitation of usable resources. As a practical example of implementation, the successful experimental results in opening door whose geometric parameters are unknown beforehand are provided.

• Proceedings of the KSRS Conference
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• 2004.10a
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• pp.425-427
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• 2004

Motivation of this study is based on these two aspects: geologic uses of ASTER and application scheme of Spectral Mixture Analysis. This study aims at geologic mapping for mineral exploration using ASTER and LANDSAT 7 ETM+ at Mongolian plateau region by SMA. After basic pre-processing such as the normalization, geometric corrections and calibration of reflectance, related to endmembers selection and spectral signature deviation, both methods using spectral library and using PPI(Pixel Purity Index) are performed and compared on a given task. Based on these schemes, SMA is performed using LANDSAT 7 ETM+ and ASTER image. As the results, fraction map showing geologic rock types are enough to meet purposes such as geologic mapping and mineral potential mapping in the case of both uses of these different types of remotely sensed images. It concluded that this approach based on SMA with LANDSAT and ASTER is regarded as one of effective schemes for geologic remote sensing.

• Journal of Institute of Control, Robotics and Systems
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• v.5 no.8
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• pp.955-960
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• 1999

This paper describes the effect of impact configurations on a single robot manipulator. The effect of different configurations of kinematically redundant arms on impact forces at their end effectors during contact with the environment is investigated. Instead of the well-known impact ellipsoid, I propose an analytic method on the geometric configuration of the impact directly from the mathematical definition. By calculating the length along the specified motion direction and volume of the geometry, we can determine the characteristics of robot configurations in terms of both the impact along the specified direction and the ability of the robot withstanding the impact. Simulations of various impact configurations are discussed at the end of this paper.

• Journal of the Ergonomics Society of Korea
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• v.9 no.2
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• pp.21-28
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• 1990

The robot motion control in the industrial robot is generally executed by the teach pendant. But, it requires much teaching time and workload to the operators. This study suggests the use of the robot motion control method by the computed keyboard in the industrial robot instead of the teach pendant. TES/CCS(Teaching Expert System/Cartesian Coordinate System) and TES/WCS(Teaching Expert System/World Coordinate System) that have been proposed to improve the robot motion control are applied for this concept. This study is intended to improve the robot motion control in TES/CCS. Parameter limitation problems in getting the motion data on position and posture of the robot in macro motion control are solved by proposed geometric algorithm. This result demonstrates reduction of the average teaching task time to the teaching position.

• Korean Journal of Computational Design and Engineering
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• v.4 no.1
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• pp.12-18
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• 1999

A deformable non-Uniform Rational B-Spline (NURBS) based volume is programed for the force reflecting exoskeleton haptic device. In this work, a direct free form deformation (DFFD) technique is applied for the realistic manipulation. In order to implement the real-time deformation, a nodal mapping technique is used to connect points on the virtual object with the NURBS volume. This geometric modeling technique is ideally incorporated with the force reflecting haptic device as a virtual interface. The results in this work introduce details for the complete set-up for the realistic virtual clay modeling task with force feedback. The force reflecting exoskeleton haptic manipulator, coupled with a supporting PUMA 560 manipulator and the virtual clay model are integrated with the graphics display, and results show that the force feedback from the realistic physically based virtual environment can greately enhance the sense of immersion.

• 제어로봇시스템학회:학술대회논문집
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• 1992.10b
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• pp.399-404
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• 1992

Curved 3D objects represented by range data contain large amounts of information compared with planar objects, but do not have distinct features for matching to those of object models. This makes it difficult to represent and identify a general 3D curved object. This paper introduces a new approach to representing and finding a holdsite of general 3D curved objects using range data. We develop a three-dimensional generalized Hough transformation which can be also applied to general 3D curved object recognition and which reduces both the computation time and storage requirements. Our approach makes use of the relative geometric differences between particular points on the object surface and some model points which are prespecified arbitrarily and task dependently.

• Journal of Computational Design and Engineering
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• v.3 no.2
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• pp.121-131
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• 2016

Organic modeling of 3D characters is a challenging task when it comes to correctly modeling the anatomy of the human body. Most sketch based modeling tools available today for modeling organic models (humans, animals, creatures etc) are focused towards modeling base mesh models only and provide little or no support to add details to the base mesh. We propose a hybrid approach which combines geometrical primitives such as generalized cylinders and cube with Shape-from-Shading (SFS) algorithms to create plausible human character models from sketches. The results show that an artist can quickly create detailed character models from sketches by using this hybrid approach.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2014.11a
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• pp.100-101
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• 2014

The generation of 3D models for freeform buildings is an important task while continuous monitoring of the related spatial information at different time phases. Realistic models of freeform building have to provide high geometric accuracy and detail at an effective data size.(Al-kheder, S. 2008) The efficiency of this image-based technique has been increased considerably by the development of digital technologies. Furthermore, 3D data collection based on laser scanning has become an high quality 3D models for construction site. Therefore, in this research, we have an effort to review construction methods to make freeform envelope of building using 3D scanning technology.