| 1 | Multiple Measurement Models of Articulated Arm Coordinate Measuring Machines显示文摘The existing articulated arm coordinate measuring machines(AACMM) with one measurement model are easy to cause low measurement accuracy because the whole sampling space is much bigger than the result in the unstable calibration parameters. To compensate for the deficiency of one measurement model, the multiple measurement models are built by the Denavit-Hartenberg's notation, the homemade standard rod components are used as a calibration tool and the Levenberg-Marquardt calibration algorithm is applied to solve the structural parameters in the measurement models. During the tests of multiple measurement models, the sample areas are selected in two situations. It is found that the measurement errors' sigma value(0.083 4 mm) dealt with one measurement model is nearly two times larger than that of the multiple measurement models(0.043 1 mm) in the same sample area. While in the different sample area, the measurement errors' sigma value(0.054 0 mm) dealt with the multiple measurement models is about 40% of one measurement model(0.137 3 mm). The preliminary results suggest that the measurement accuracy of AACMM dealt with multiple measurement models is superior to the accuracy of the existing machine with one measurement model. This paper proposes the multiple measurement models to improve the measurement accuracy of AACMM without increasing any hardware cost. | ZHENG Dateng XIAO Zhongyue XIA Xiang | 2015 | Chinese Journal of Mechanical Engineering2015，28，5： | 6 |
| 3 | Integrated constellation design and deployment method for a regional augmented navigation satellite system using piggyback launches显示文摘The method proposed in this paper is adopted to solve problem B of the 9th China Trajectory Optimization Competition(CTOC).An accurate and economical constellation design strategy for regional augmented navigation satellite systems(RANSSs)has attracted a substantial amount of research interest owing to the increased demand for navigation services in complex environments.This paper proposes a hybrid method of constellation design and deployment for a RANSS to satisfy the navigation performance requirements and minimize the construction cost.First,the search spaces of the design parameters are determined by analyzing the orbital parameters of piggyback launches.Second,the constellation is designed as a combined Walker constellation and optimized by a differential evolution(DE)algorithm.Finally,optimal strategies for deploying satellites to the desired orbits are obtained using a transfer optimization design.The method was adopted to design a RANSS for servicing the 182 cities in the Asia-Pacific region.The configuration consists of five orbital planes and 80 navigation satellites and achieves a low construction cost with 10 piggyback launches.Furthermore,the constellation can cooperate with an existing navigation satellite system to further improve the navigation accuracy for all cities.The results reveal that the RANSS design and deployment problem can be effectively solved with a low construction cost and high navigation performance. | Shuai Guo Wanmeng Zhou Jin Zhang Fuyu Sun Dateng Yu | 2021 | Astrodynamics2021，5，1： | 0 |
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