• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2000.11a
• /
• pp.670-673
• /
• 2000

This paper attempt analysis and computer simulation of dynamics of a set of dual multi-joint fingers with soft-deformable tips which are grasping. Firstly, a set of differential equation describing dynamics of the fingers and object together with geometric constraint of tight area-contacts is formulated by Euler-Lagrange's formalism. Secondly, problems of controlling both the internal force and the rotation angle of the grasped object under the constraints of area-contacts of tight area-contacts are discussed. The effect of geometric constraints of area-contacts on motion of the overall system is analyzed and a method of computer simulation for overall system of differential-algebraic equations is presented. Finally, simulation results are shown and the effects of geometric constraints of area-contact is discussed.

• Journal of Advanced Marine Engineering and Technology
• /
• v.30 no.3
• /
• pp.428-437
• /
• 2006

This paper attempts to derive and analyze the dynamic system of grasping a rigid object by means of two multi-degrees-of-freedom robot flngers with soft and deformable tips. It is shown firstly that a set of differential equation describing dynamics system of the manipulators and object together with geometric constraint of tight area-contacts is formulated by Lagrange's equation. It is shown secondly that the problems of controlling both the forces of pressing object and the rotation angle of the object under the geometric constraints are discussed. In this paper. the control method for dynamic stable grasping and enhancing dexterity in manipulating things is proposed. It is illustrated by computer simulation that the control system gives the performance improvement in the dynamic stable grasping of the dual fingers robot with soft tips.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2005.06a
• /
• pp.1060-1067
• /
• 2005

This paper attempts to derive and analyze the dynamic system of pinching a rigid object by means of two multi-degrees-of-freedom robot fingers with soft and deformable tips. It is shown firstly that a set of differential equation describing dynamics system of the manipulators and object together with geometric constraint of tight area-contacts is formulated by Lagrange's equation. It is shown secondly that the problems of controlling both the forces of pressing object and the rotation angle of the object under the geometric constraints are discussed. In this paper, the control method for dynamic stable grasping and enhancing dexterity in manipulating things is proposed. It is illustrated by computer simulation that the control system gives the performance improvement in the dynamic stable grasping of the dual fingers robot with soft tips.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
• /
• 2002.10a
• /
• pp.219-224
• /
• 2002

This paper aims to derive a mathematical model of the dynamics of handling tasks in robot finger which stable grasping and manipulates a rigid object with some dexterity. Firstly, a set of differential equation describing dynamics of the manipulators and object together with geometric constraint of tight area-contacts is formulated by Lagrange's equation. Secondly, problems of controlling both the internal force and the rotation angle of the grasped object under the constraints of area-contacts of tight area-contacts are discussed. The effect of geometric constraints of area-contacts on motion of the overall system is analyzed and a method of computer simulation for overall system of differential-algebraic equations is presented. Thirdly, simulation results are shown and the effects of geometric constraints of area-contact is discussed. Finally, it is shown that even in the simplest case of dual single D.O.F manipulators there exists a sensory feedback from sensing data of the rotational angle of the object to command inputs to joint actuators and this feedback connection from sensing to action eventually realizes secure grasping of the object, provided that the object is of rectangular shape and motion is confined to a horizontal plane.

• Archives of design research
• /
• v.5 no.1
• /
• pp.57-68
• /
• 1992

The purpose of this study was to describe patterns of two dimensions, clothes of three dimensions. The IBM 32Bit Computer Graphics was used in this study. TIPS, LUMENA, FREE STYLE and TOP AS were used as soft wares. The procedures of study were as follows; 1.Selection of motives. 2.Selection of color and gradation. 3.Making patterns. 4.Input patterns of two dimensions on TOP AS. 5.Making Mannequin and fashion illustration. 6.Mapping patterns onto fashion illustration.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.26 no.12
• /
• pp.853-857
• /
• 2013

We design, develope and test a parallel active polymer pen lithography (PPL) device, which consists of individually addressable elastomeric probe tips. The PPL array chip is fabricated using soft lithography method with polydimethylsiloxane (PDMS) material. Individual probe can be pneumatically actuated via a computer controlled interface. We demonstrate parallel writing with 16 individually addressed pens, with each pen producing a different pattern in the same run. The largest proof-of-concept array fabricated is $4{\times}4$ with a spacing of $250{\mu}m$ in both x and y axes.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1997.10a
• /
• pp.492-495
• /
• 1997

This paper aims to derive a mathematical model of the dynamics of handling task in field robot which stable grasping and manipulates a rigid object with some dexterity. Firstly, a set of differential equation describing dynamics of the manipulators and object together with geometric constraints of tight area-contacts on motion of the overall system is analyzed and a method of computer simulation for overall system of differential-algebraic equations is presented. Thirdly, simulation results are shown and the effects of geometric constraints of contact-area are discussed. Finally, it is shown that even in the simplest case of dual single D.O.F. manipulators there exists a sensory feedback from sensing data of he rotational angle of the object to command inputs to joint actuators and this feedback connection from sensing to action eventually realizes secure grasping of the object, provided that he object is of rectangular shape and motion is confined to a horizontal

• Structural Engineering and Mechanics
• /
• v.85 no.3
• /
• pp.337-351
• /
• 2023

In this paper, the shear behavior of soft filling in rectangular-hollow concrete specimens was simulated using the 2D particle flow code (PFC2D). The laboratory-measured properties were used to calibrate some PFC2D micro-properties for modeling the behavior of geo-materials. The dimensions of prepared and modeled samples were 100 mm×100 mm. Some disc type narrow bands were removed from the central part of the model and different lengths of bridge areas (i.e., the distance between internal tips of two joints) with lengths of 30 mm, 50 mm, and 70 mm were produced. Then, the middle of the rectangular hollow was filled with cement material. Three filling sizes with dimensions of 5 mm×5 mm, 10 mm×5 mm, and 15 mm×5 mm were provided for different modeled samples. The parallel bond model was used to calibrate and re-produce these modeled specimens. Therefore, totally, 9 different types of samples were designed for the shear tests in PFC2D. The shear load was gradually applied to the model under a constant loading condition of 3 MPa (σc/3). The loading was continued till shear failure occur in the modeled concrete specimens. It has been shown that both tensile and shear cracks may occur in the fillings. The shear cracks mainly initiated from the crack (joint) tips and coalesced with another one. The shear displacements and shear strengths were both increased as the filling dimensions increased (for the case of a bridge area with a particular fixed length).

• Archives of Reconstructive Microsurgery
• /
• v.24 no.2
• /
• pp.41-49
• /
• 2015

Free or pedicled vascularized fibular grafts (VFG) are useful for the reconstruction of large skeletal defects, particularly in cases of scarred or avascular beds, or in patients with combined bone and soft tissue defects. Compared to non-VFG, VEG, which contains living osteocytes and osteoblasts, maintains its own viability and serves as good osteoconductive and osteoinductive graft. Due to its many structural and biological advantages, the free fibular osteo- or osteocutaneous graft is considered the most suitable autograft for the reconstruction of long bone defects in the injured extremity. The traditional indication of VFG is the long bone and soft tissue defect, which cannot be reconstructed using a conventional operative method. Recently, the indications have been widely expanded not only for defects of midtibia, humerus, forearm, distal femur, and proximal tibia, but also for the arthrodesis of shoulder and knee joints. Because of its potential to allow further bone growth, free fibular epiphyseal transfer can be used for the hip or for distal radius defects caused by the radical resection of a tumor. The basic anatomy and surgical techniques for harvesting the VFG are well known; however, the condition of the recipient site is different in each case. Therefore, careful preoperative surgical planning should be customized in every patient. In this review, recently expanded surgical indications of VFG and surgical tips based on the author's experiences in the issues of fixation method, one or two staged reconstruction, size mismatching, overcoming the stress fracture, and arthrodesis of shoulder and knee joint using VFG are discussed with the review of literature.

• Archives of Plastic Surgery
• /
• v.50 no.3
• /
• pp.279-287
• /
• 2023

Background Hypothenar free flaps (HTFFs) have been widely used for reconstructing palmar defects. Although previous anatomical and clinical studies of HTFF have been conducted, this technique still has some limitations. In this study, we describe some tips for large flap design that allows for easy harvesting of HTFFs with minimal donor site morbidity. Methods A total of 14 HTFF for hand defect reconstruction were recorded. The oblique flap was designed in the proximal HT area following relaxed skin tension line along the axis between fourth web space and 10 mm ulnar side of pisiform. A flap pedicle includes one or two perforators with ulnar digital artery and HT branch of basilic vein. In addition, innervated HTFF can be harvested with a branch of ulnar digital nerve. Electronic medical records were reviewed to obtain data on patients' information, operative details, and follow-up period. In addition, surgical outcome score was obtained from the patient, up to 10 points, at the last follow-up. Results Mean harvest time was 46 minutes, and two perforators were included in 10 cases. The mean flap area was 10.84 cm². There were no problems such as donor site depression, scar contracture, keloids, wound dehiscence, numbness or neuroma pain at donor sites, and hypersensitivity or cold intolerance at flap site, either functionally or aesthetically. Conclusion Palmar defect reconstruction is challenging for hand surgeons. However, large HTFF can be harvested without complications using the oblique axis HTFF technique. We believe our surgical tips increase utility of HTFF for palmar defect reconstruction.