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Error compensation for snake arm maintainer under variable loads
Guodong Qin,Huapeng Wu,Aihong Ji,Huan Shen,Qian Li,Qingfei Han,Zhikang Yang,Shikun Wen 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.2
The cable-driven snake arm maintainer (SAM) simplifies the electronics of the entire snake arm and is well suited for operation in narrow and high-risk environments. However, the structural features of the SAM, the large slenderness ratio and the effects of variable loads and rigid-flexible coupling deformation lead to large end position error. In order to improve the positional accuracy, a joint space error compensation model of a SAM is constructed using the matrix differentiation method. The error parameters under different loads and different poses are identified based on the principles of variable parameter error compensation and a linearized variable-load variable-parameter model. Parameter errors are then calculated by the Levenberg-Marquardt nonlinear damped least-squares algorithm. Finally, we verify the effectiveness of the proposed algorithm by simulation and error compensation experiments. The results of the study provide a theoretical basis for further accuracy improvement and application expansion of the SAM.
Research on the cable-driven endoscopic manipulator for fusion reactors
Guodong Qin,Yong Cheng,Aihong Ji,Hongtao Pan,Yang Yang,Zhixin Yao,Yuntao Song Korean Nuclear Society 2024 Nuclear Engineering and Technology Vol.56 No.2
In this paper, a cable-driven endoscopic manipulator (CEM) is designed for the Chinese latest compact fusion reactor. The whole CEM arm is more than 3000 mm long and includes end vision tools, an endoscopic manipulator/control system, a feeding system, a drag chain system, support systems, a neutron shield door, etc. It can cover a range of ±45° of the vacuum chamber by working in a wrap-around mode, etc., to meet the need for observation at any position and angle. By placing all drive motors in the end drive box via a cable drive, cooling, and radiation protection of the entire robot can be facilitated. To address the CEM motion control problem, a discrete trajectory tracking method is proposed. By restricting each joint of the CEM to the target curve through segmental fitting, the trajectory tracking control is completed. To avoid the joint rotation angle overrun, a joint limit rotation angle optimization method is proposed based on the equivalent rod length principle. Finally, the CEM simulation system is established. The rationality of the structure design and the effectiveness of the motion control algorithm are verified by the simulation.
Yongda Zhong,Zhiting Li,Shujuan Liu,Aihong Yang,Lipan Liu,Yanqiang Li,Meng Xu,Faxin Yu 강원대학교 산림과학연구소 2018 강원대학교 산림과학연구소 학술대회 Vol.2018 No.09
Cinnamomum camphora (Lauraceae) is an evergreen broad-leaved tree and distributed in the south of China and Japan. This species has been widely cultivated in many countries because of its aromatic oils, insect-repellent effects and ornamental value. Despite its vast utilization and cultivation, little is known about its genetic diversity and population genetics. To date, only a few genomic simple sequence repeat (SSR) markers were developed in C. camphora and no genic-SSR primers were available yet. Thus, it is necessary to develop more genic-SSR markers, which will facilitate the genetic studies of Cinanamomum. In this study, a total of 74,289 simple sequence repeats (SSRs) were found in 56,124 unigenes, of which 14,225 unigenes contained more than one SSR locus. Among these SSR loci, the mono-nucleotide repeats were the most frequent, with a frequency of 61.14%, followed by 24.87% di-nucleotide repeats and 12.87% tri-nucleotide repeats. Twenty-one polymorphic SSR markers were developed and validated in 45 camphor trees. The 21 loci were further examined for genetic diversity of 38 provenances, 190 individuals in the whole natural distribution area of camphor tree in China. The results showed that 74 polymorphic sites were detected with average 2.74 polymorphic were detected for each prime. The means of observed and expected heterozygosities were 0.4446 and 0.4419, respectively. Nei's and Shannon’s information index for these populations were 0.4400 and 0.7193, respectively. The genetic similarity coefficient of 38 provenances was between 0.05 and 0.95, with an average of 0.17.The smallest genetic distance is JXWY and JXRJ and the genetic distance between JXTG and GZDZ was the largest. Cluster analysis in 0.88 genetic distance can divide into five groups. Jiangxi provenances clustered into two groups, of which JXAY grouped into one group and other provenances grouped into another group. Other provenances of China grouped three small branches: CQYY and HNHH, GZDZ and SCLZ, and other provenances. The clustering results showed that the genetic components of camphor tree in China had obvious regional features. The analysis of molecular variance exhibited that 77% of genetic variation was observed within the populations. The novel genic-SSR markers will not only benefit genetic diversity analysis and wild resources conservation of C. camphora, but also contribute to exploring the further evolutionary history and genetic differentiation pattern of Cinnamomum.