Search | Korea Science

Kinematic Correction and a Design for Velocity Trajectory to Reduce an Odometer Error of Wheeled-Mobile Robots (구륜 이동 로봇의 주행오차 감소를 위한 기구학적 보정과 속도궤적의 설계)

Kim, Jong-Su;Mun, Jong-U;Park, Jong-Guk
- Journal of the Institute of Electronics Engineers of Korea SC
- /
- v.37 no.3
- /
- pp.9-18
- /
- 2000
This paper presents methods for reducing odometer errors caused by kinematic imperfections in wheeled mobile robots. Wheel diameters and wheelbase are corrected by using encoders without landmarks. And a new velocity trajectory is proposed that compensates for an orientation error due to acceleration-resolution constraints on motor controllers. Based on this velocity trajectory, the wheel velocity of one out of two driven wheels may be changed by the traveled distance of the mobile robot. It is shown that a wheeled mobile robot can't move along a straight line exactly, even if kinematic correction are achieved perfectly, and this phenomenon is attributable to acceleration-resolution constraints on motor controllers. We experiment on a wheeled mobile robot with 2 d.o.f. and discuss the results.
PDF

A Study on the Characteristics of Marine Debris in Coastline : Daekwang Beach In Imja Island, Jeollanam-Do, Korea (해안표착물의 특성에 관한 연구 : 전라남도 신안군 임자도 대광해수욕장)

Jang, Seong-Woong;Oh, Seung-Yeol;Kim, Dae-Hyun;Yoon, Hong-Joo
- Journal of the Korean Society of Marine Environment & Safety
- /
- v.17 no.2
- /
- pp.123-129
- /
- 2011
A study on the occurrence and movement of marine debris is required for protecting the marine environment and ecosystem from marine pollution. The aim of this study is to show annual production and movement characteristics through analysis for the flow path, composition and the sources of marine debris. This study analyzed the distribution and characteristics of marine debris collected in the region of $100\;m{\times}20\;m$($=2,000\;m^2$) at the Daekwang Beach in the Yellow Sea. During the collection period from 2008 to 2010, the total weight of the marine debris was 1,445 kg in this site. The most marine debris was plastic amounting to 46.5% of the whole collection; the rest were styrofoam(20%) and wooden material(12.6%). The amount of marine debris mused from foreign country observed 155.5 kg, more than 90% of them was plastic came from China such as buoys. Additionally, this study analyzed seasonal change if marine environment to understand occurrence amount change if marine debris. 2009 and 2010 was high occurrence ratio in season that the north wind is very strong and the occurrence rate appeared highest by 40% in the summer(July) of 2008 that appeared westbound tidal current. Overall, marine Debris mused from foreign country was high occurrence ratio in January, May and then November has a lot of quantity secondly. While, occurrence ratio was the highest by 46% summer(July) in 2008, but in 2009 and 2010 showed the lowest rate to 4%.
https://doi.org/10.7837/kosomes.2011.17.2.123 인용 PDF KSCI