• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.710-713
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• 2005

Many impact or drop test researches of home appliances are published, but those of toys cannot be found easily. External impacts are the primary causes of fracture of toys. For impact proof design, the finished product should pass an impact test after molding design. There are several international toy safety standards or requirements such as US CPSC(Consumer Product Safety Commission), ASTM F963-96a, EN71 and so on. The puppy robot which patrols around the house, namely, the watchdog was selected to investigate toy safety because it has considerable weight and outer panels are made of plastics. First the model of watchdog robot was obtained by 3 dimensional scan. Surface data can be generated from 3D polygon data of the watchdog. A reliable drop simulation method for the watchdog was established using Pam-crash program according to Korean toy safety standards. When there is a low impact allowance value, the molding design should be reinforced or changed. It was found that the maximum impact stress reaches the ultimate stress of panel material.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.33 no.5
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• pp.380-385
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• 2020

Over the past decade, small robots have been of particular interest in the engineering field. Among the various types of small robots, biomimetic robots, which mimic animals and insects, have been developed for special activities in areas where humans cannot physically access. The optimal motion of a walking robot can be determined by the characteristics of the traversed surface (e.g., roughness, curvature, slope, materials, etc.). This study proposes three types of piezoelectric structures using different driving mechanisms, depending on the application range of the small walking robots. Dynamic modeling using computer-aided engineering optimized the shape of the robot to maximize its moving characteristics, and the results were also verified through its fabrication and experimentation. Three types of robots, named by their actuator shapes as I, π, & T-shape, were proposed regarding application for small scale ambulatory robots to different terrain conditions. Among these, the T-shaped robots were shown to have a wide range of speeds (from 2 mm/s up to 255 mm/s) and good carrying capacity (up to 10 g at 50 mm/s) through driving experiments. Based on this study, we proposed possible application areas for the three types of walking robot actuators.

• Journal of IKEEE
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• v.23 no.4
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• pp.1387-1392
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• 2019

Aspherical mirrors have lighter weight and better performance than spherical mirrors, but it is difficult to process their shape and measure the processing precision. Especially, large aperture aspherical mirrors mounted on satellites need high processing precision and long processing time. The computerized numerically controlled machine of gantry type has been used in polishing process, but it has difficulties in processing the complex shapes due to the lack of degrees of freedom. In order to overcome this problem we developed a polishing system using an articulated industrial robot. The system consists of tool path generating program, real-time robot monitoring, and control program. We show the performance of the developed system through the computer simulation and actual robot operation.

• The Journal of Korea Robotics Society
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• v.1 no.2
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• pp.188-196
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• 2006

During the communication and interaction with a human using motions or gestures, a humanoid robot needs not only to look like a human but also to behave like a human to make sure the meanings of the motions or gestures. Among various human-like behaviors, arm motions of the humanoid robot are essential for the communication with people through motions. In this work, a mathematical representation for characterizing human arm motions is first proposed. The human arm motions are characterized by the elbow elevation angle which is determined using the position and orientation of human hands. That representation is mathematically obtained using an approximation tool, Response Surface Method (RSM). Then a method to generate human-like arm motions in real time using the proposed representation is presented. The proposed method was evaluated to generate human-like arm motions when the humanoid robot was asked to move its arms from a point to another point including the rotation of its hand. The example motion was performed using the KIST humanoid robot, MAHRU.

• Smart Structures and Systems
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• v.9 no.6
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• pp.535-547
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• 2012

Controlling the balance of motion in a context involving a biped robot navigating a rugged surface or a step is a difficult task. In the present study, a $3{\times}5$ flexible piezoelectric tactile sensor array is developed to provide a foot pressure map and zero moment point for a biped robot. We introduce an innovative concept involving structural electrodes on a piezoelectric film in order to improve the sensitivity. The tactile sensor consists of a polymer piezoelectric film, PVDF, between two patterned flexible print circuit substrates (FPC). Additionally, a silicon rubber bump-like structure is attached to the FPC and covered by a polydimethylsiloxane (PDMS) layer. Experimental results show that the output signal of the sensor exhibits a linear behavior within 0.2 N ~ 9 N, while its sensitivity is approximately 42 mV/N. According to the characteristic of the tactile sensor, the readout module is designed for an in-situ display of the pressure magnitudes and distribution within $3{\times}5$ taxels. Furthermore, the trajectory of the zero moment point (ZMP) can also be calculated by this program. Consequently, our tactile sensor module can provide the pressure map and ZMP information to the in-situ feedback to control the balance of moment for a biped robot.

• Journal of International Academy of Physical Therapy Research
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• v.11 no.2
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• pp.2021-2027
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• 2020

Background: Previous robot-mediated gait training has been proven several limitations such as pointless repeated motion training, decreased presence, etc. In this research, adult stroke patients were participated in robot-mediated gait training accompanied with or without virtual reality program. Objectives: Exploring whether the results indicated virtual reality system has contribution to muscle strength and balance ability. Design: A case series research, cross-over trial. Methods: Eleven participants (male 4, female 7) with adults diagnosed as stroke from medical doctor ware engaged. The participants received 2 treatment sessions of identical duration, robot-assisted gait training with virtual reality and robot-assisted gait training with screen-off randomly crossed over include 1-day for each person of wash-out period. The parameter was muscle activity, the researchers assessed sEMG (surface electromyography). Results: The result showed less muscle activities during training in robot-assisted gait training with virtual reality circumstances, and these indicated muscles were gluteus medius muscle, vastus medialis muscle, vastus intermedius and vastus lateralis muscle, semimembranosus muscle, gastrocnemius-lateral head, and soleus muscle (P<.05). Conclusion: In this study, we analyzed the outcome of muscle activity for clinical inference of robot-assisted gait training with virtual reality (VR). Less muscle activity was measured in the treatment accompanied by VR, therefore, a more systematic, in-depth and well-founded level of follow-up research is needed.

• Journal of the Korean Institute of Intelligent Systems
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• v.20 no.4
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• pp.509-515
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• 2010

In this paper, the mechanism that can walk efficiently in wet land or sand area is proposed. A vision camera is attached to the mechanism, which makes a kind of biologically inspired robot for coast guard. This visionary information enables the biologically inspired robot to react in peripheral environment by a soft-computing algorithm. In addition, the biologically inspired robot can achieve the mission appointed by a programmer connecting with outside, based on RF and Blue-tooth communication module. Therefore, the purpose of this research is the implementation of the biologically inspired robot that can operate most adaptively in sand and wet surface based on Theo Jansen mechanism.

• Journal of the Korean Society of Safety
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• v.9 no.1
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• pp.31-39
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• 1994

In this study, image processing were performed to recognize the shape of objects and find its center coordinate and direction to grisp the objects by the robot automatically. The proposed methods could be applied to objects even if light is reflected, and to identify the insides and outsides of objects by using the photo sensor and the difference of surface conditions. Also image segmentation is performed to the objects close to each other. These image processing methods will be increased the safety of operators by the automation of dangerous and hazardous machine works.

• 제어로봇시스템학회:학술대회논문집
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• 1994.10a
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• pp.597-600
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• 1994

A Robot system to realize a painting using a writing brush is explained here. Based on the three-dimensional data about the target china, the movements of the writing brush is determined. The movement is realized by the movement of two robot manipulators which move coordinatedly. Experimental results reveals the applicability of one system.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.379-382
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• 1996

Evolution Strategy is used as an effective search algorithm in optimization problems and Sliding Mode Control is well known as a robust control algorithm. In this paper, we propose a Sliding Mode Control Method for robot manipulator using Evolution Strategy. Evolution Strategy is used to estimate Sliding Mode Control Parameters such as sliding surface gradient, continuous function boundary layer, unknown plant parameters and switching gain. Experimental results show the proposed control scheme has accurate and robust performances with effective search ability.