http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
- 中文 을 입력하시려면 zhongwen을 입력하시고 space를누르시면됩니다.
- 北京 을 입력하시려면 beijing을 입력하시고 space를 누르시면 됩니다.
RISS 인기검색어
- 검색키워드
- 저자 : Shahram Hadian Jazi (검색결과 3 건)
- 무료
- 기관 내 무료
- 유료
-
Map-merging using maximal empty rectangles in a multi-robot SLAM process
Shahram Hadian Jazi 대한기계학회 2020 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.34 No.6
A map-merging algorithm is proposed where reduced element maps are applied instead of grid maps and the maximal empty rectangles are applied as their features. Simultaneous localization and mapping (SLAM) refer to the process where a robot provides the environment map without any knowledge about its own position. Due to error accumulation, required time, saving lives and reasons alike, applying a single robot in the SLAM process is not justified. In such applications, many robots are to be applied in the SLAM process in a parallel sense. The map-merging process is one of the challenging topics in a multi-robot simultaneous localization and mapping process in producing a global map of the environment. In this study, a centralized algorithm is introduced for map-merging based on maximal empty rectangles as the features of local maps without any knowledge about robots' initial or relative positions. Three examples and one experiment are applied in validating the performance of this newly proposed algorithm. The obtained results indicate that this algorithm can merge local maps with small overlapping areas in relation to the whole map, subject to multiple sources of error due to the difference in scales, diversity of agents applied and measurement noise.
-
Mohsen Rezaei,Mehrdad Poursina,Shahram Hadian Jazi,Farhad Haji Aboutalebi 대한기계학회 2018 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.32 No.8
Time-dependent mesh stiffness is a most important reason of vibration and dynamic excitation in gear sets. In this research, analytical formulas of the helical gear set and the planetary gear system are combined to calculate the time-dependent mesh stiffness of the helical planetary gear system. For this purpose, at the first step, the analytical equations are derived for the spur gear pair. Then by dividing a helical tooth into the several independent thin spur tooth slices, the helical gear pair mesh stiffness is extracted. Finally, these equations are extended to the helical planetary gear system. The suggested analytical results and those which obtained by the finite element method (FEM) are compared and are in good agreement when the helix angle is less than 15 degrees. Also, the helical planetary gear system mesh stiffness in different cases such as fixed carrier, fixed sun gear and fixed ring gears is calculated. These results show that the value of mesh frequency ratio in each case scales the mesh stiffness shapes in the rotation angle direction. In other words, mesh frequency ratio parameter determines the number of meshing period in each rotation of planets.
-
Multi crack detection in helical gear teeth using transmission error ratio
Mohsen Rezaei,Mehrdad Poursina,Shahram Hadian Jazi,Farhad Haji Aboutalebi 대한기계학회 2019 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.33 No.3
Gear systems are used to transmit power in the industry when accuracy and synchrony are needed and helical gear systems are used in more accurate and high-speed industries. It is important to ensure that these systems work faultlessly, therefore the detection of the crack location and situation is very efficient in the gear systems. In this research, a new approach is proposed to detect the multi crack location and length in the helical gear teeth. To this end, after giving an explanation of helical gear mesh stiffness and demonstrating the helical gear pair dynamic modeling, the transmission error ratio method is used to detect the cracks locations and lengths. Then, according to solved examples, when the cracks locations are far enough that their effects on the transmission error are completely separated, the cracked teeth and the lengths of cracks can be detected exactly, and when the cracks are in adjacent teeth, according to the cracks lengths and depths and their effects overlap, the number of cracks and their lengths can be detected exactly, approximately or absolutely undetectable.
연관 검색어 추천
이 검색어로 많이 본 자료
활용도 높은 자료
