Parametric Design Optimization of a Tail Mechanism Based on Tri-Wheels for Curved Spoke-Based Stair-Climbing Robots

JeongPil Shin,YoungHwan Kim,Dong-Yoon Kim,Gil Ho Yoon,TaeWon Seo 한국정밀공학회 2023 International Journal of Precision Engineering and Vol.24 No.7

Overcoming stairs is an important requirement for mobile robots. Therefore, many studies have been conducted to develop robots with novel stair-climbing mechanisms. A curved-spoke-based stair-climbing robot has been developed to overcome stairs, but had some limitations during stair climbing, such as damage caused by friction with the edge of the stair and impact during locomotion. In a previous study, several tail mechanisms were suggested to solve these problems, and the tri-wheel tail mechanism showed remarkable performance improvements. However, the previous study used only one step size of 300 ×160 mm2. Therefore, in this study, a robust optimal design of the tri-wheel tail mechanism using the Taguchi method is conducted to achieve outstanding performance improvements even for stairs of various sizes and different climbing speeds as user conditions. The design of simulations of the tri-wheel tail mechanisms are performed via orthogonal arrays using a commercial dynamic simulation software tool. The objective function is to minimize the minimum required friction coefficient for a mobile robot to climb stairs without slip. The performance improvements are verified experimentally using a measurable performance index. Thus, these findings can be used to design stair-climbing mobile robots.

그릇 수거를 위한 그리퍼 메커니즘 설계 연구

신정필(JeongPil Shin),원지호(JeeHo Won),김영환(YoungHwan Kim),서태원(TaeWon Seo) 대한기계학회 2023 대한기계학회 춘추학술대회 Vol.2023 No.5

LEVO: Mobile Robotic Platform Using Wheel-Mode Switching Primitives

DongHan Son,JeongPil Shin,Young-Hwan Kim,TaeWon Seo 한국정밀공학회 2022 International Journal of Precision Engineering and Vol.23 No.11

This paper proposes a mobile robotic platform, LEVO, which uses a normal wheel and a curved-spoke tri-wheel (CSTW). The normal wheel is used for driving on flat terrain, and the CSTW is used for stair climbing. In order to use the two mechanisms independently, a switching mechanism that consists of ball screw, linear motion guide, and actuator is added. Therefore, the proposed robot can be driven in both wheel mode and CSTW mode. The CSTW mode is implemented by lowering the CSTW to the ground and raising the rear wheels (caster), while the wheel mode is implemented by lowering caster to the ground and raising the CSTW. In order to design the switching mechanism and CSTW mechanism, static and kinematic analyses are performed. Further, a prototype is assembled to verify the mode-switching, stair climbing, and wheel-driving functions. The experiment was repeated on stairs with different sizes and materials. The results show that robots can drive on both flat terrain and stairs. Therefore, the proposed robot is expected to be useful as a mobile robot platform suitable for indoor environments.

Optimal Design of Body Profile for Stable Stair Climbing Via Tri-wheels

Younghwan Kim,Donghan Son,Jeongpil Shin,TaeWon Seo 한국정밀공학회 2023 International Journal of Precision Engineering and Vol.24 No.12

In this paper, we propose a mobile robot platform that is an improved form of LEVO. The LEVO uses a regular wheel and curved spoke triwheel(CSTW) system to drive flat terrain and stair climbs. However, this robot has problems when climbing stairs: it’s bottom profile collides with the stairs, resulting in huge jerk. To solve this problem, in this study, attempts to reduce the jerk value by applying a blade using a B-spline to the bottom profiles where the robot collides with the stairs. At this time, by reducing jerk, it can contribute to extending the life of the robot and improving driving stability. This study involved two steps. First, simulation was performed by adjusting the number and position of control points of the curve (B-spline). In this process, the orthogonal arrangement was applied among the optimal design techniques to finally reduce the jerk value by 92% and the driving torque needed to climb the stairs by 9.5%. At this time B-spline has one control point and the position is (300, 15). This simulation result was verified experimentally using a test bench and a prototype robot. As a result, it was confirmed that the jerk was reduced by 66.7%. Simulations and experimental verification based on them have shown that the proposed method is sufficiently effective in real environment.

Fischer-Tropsch 반응을 포함하는 GTL 공정 Fixed-Bed 반응기의 Start-up에 따른 내부 변화 동적모사

홍기훈(Gi Hoon Hong),박정필(Jeongpil Park),신동일(Dongil Shin) 한국가스학회 2013 한국가스학회 학술대회논문집 Vol.2013 No.5

UN GHS와 위험물안전관리법상의 위험물질 분류기준 비교 및 선진화 방안 연구

이봉우(Bong Woo Lee),이기준(Kijun Lee),박정필(Jeongpil Park),신동일(Dongil Shin) 한국가스학회 2013 한국가스학회지 Vol.17 No.5

급속한 산업발전과 더불어 전 세계적으로 약 10만 여종의 산업용 물질이 사용되고 있으며, 매년 2,000여종의 신규물질이 개발되고 있다. 이러한 물질들은 인류문화 발전에 크게 기여하고 있지만 일부 물질들은 유해, 위험성등의 잠재적인 위험성을 가지고 있다. 우리나라는 세계 7대 화학제품 생산국가로, 활발한 수출?입을 통해 국가부흥에 기여하고 있다. 최근 REACH 및 GHS와 같은 화학물질 안전관리에 대한 국제적 관심이 증대되어 그에 따른 효율적인 화학물질 관리체계 구축에 대한 필요성이 커지고 있다. 본 연구에서는 화학물질에 대한 국내, UN GHS 물리화학적 위험성 분류기준, 표지 및 위험성 평가 시험방법, 위험물안전관리법 등에서 정한 분류정보의 차이점을 비교하였으며, 또한 국제 환경변화에 대응하기 위하여 선택가능방식(building block approach)으로 GHS제도 도입방안을 제시하였다. 또한 소비자에게 화학물질의 통일화된 위험성 정보를 제공하여 산업체가 화학물질을 해외로 수출?입 하는데 무역장벽을 해소하고자 하였다. With the rapid change of industry and the development of science and technology, more than 100,000 industrial chemicals are being used and 2,000 new materials are developed every year. Chemical products have had favorable influence on our daily life and contributed very much to the prosper of human culture. But some materials are inherently poisonous and dangerous. Korea ranks as the number 7 in world’s chemical products market and the chemical sector is contributing to the economic revival through importing and exporting of the products. With the increasing domestic as well as international interests about REACH and GHS, the need for the effective and efficient chemical material management system is getting bigger and bigger. In this research, we compare the criteria in UN GHS and Safety Control of Dangerous Substances Act of Korea for the development of global standard test methods and the classification and labelling for the chemicals, and suggest an advancement plan for the introduction of the GHS in a building block approach. In addition, providing the harmonized information about chemical hazards is suggested for the elimination of international trade barriers for chemical industries.

LED가 결합된 야간풍력발전 활용을 포함한 해상환경 바이오매스 생산시스템의 최적 설계

홍기훈(Gi Hoon Hong),조성현(Sunghyun Cho),강훈(Hoon Kang),박정필(Jeongpil Park),김태옥(Tae-Ok Kim),신동일(Dongil Shin) 한국가스학회 2015 한국가스학회지 Vol.19 No.2

최근 화석연료의 사용증가에 따라 대량으로 배출되는 이산화탄소는 지구 온난화 현상을 일으키는 온실가스 중 하나로 지정되어 국제협약을 통하여 온실가스의 배출을 저감하도록 규제하고 있다. 본 연구에서는 이산화탄소를 저감하는 방법 중의 하나로, 3세대 바이오매스 생산시스템인 해조류를 활용한, 지속가능한 신 개념의 FPSO로서 해상환경 바이오매스 생산시스템의 최적구조를 설계하였다. 이를 위해 격자로 구조물을 설치한 후 해조류의 주변에 LED 조명을 비추어 성장을 최대화 시키는 시스템을 구상하였다. 그리고 기존 해조류의 성장자료를 통하여 해조류의 성장 모델을 만든 후 풍력발전기와 LED 조명을 포함하는 바이오매스 생산시스템을 모델링하여 최적화 도구인 GAMS 프로그램을 이용하여 본 시스템이 환경적 관점뿐만 아니라 경제성 측면에서도 타당성을 가질 수 있는 최적구조를 설계하였다. 또한 기존의 해상환경 바이오매스 생산시스템과 비교하여 최적구조를 제안하였다. Carbon dioxide was designated as one of greenhouse gases that cause global warming. Among various ways to solve the CO<SUB>2</SUB> emission issue, the 3rd-generation biomass (algae) production is considered as a viable method to reduce CO<SUB>2</SUB> in the atmosphere. In this research, we propose a design of an innovative sustainable production system by utilizing the 3rd generation biomass in the environment of floating production storage and offloading (FPSO). Existing biomass production systems depend on the solar energy and they cannot continue producing biomass at night. Electricity produced from offshore wind farms also need an efficient way to store the energy through energy storage system (ESS) or deliver it real-time through power grid, both requiring heavy investment of capital. Thus, we design an offshore grid structure harnessing LED lights to supply the necessary light energy, by using the electricity produced from the wind farm, resulting in the maximized production of biomass and efficient use of wind farm energy. The final design integrates the biomass production system enhanced by LED lights with a wind power generation. The suggested NLP model for the optimal design, implemented in GAMS, would be useful for designing improved offshore biomass production systems combined with the wind farm.