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25. A Sweeping and Grinding Methods Combined Hybrid Sampler for Asteroid Exploration

Author

Fanzhang Huang, Chaojun Jiang, Aiguo Song, Jun Zhang, Chengcheng Dong, Fan Huang, and Lu Xi

Subjects
0209 industrial biotechnology, Computer simulation, Drill, business.industry, Sampling (statistics), Rotational speed, 02 engineering and technology, 01 natural sciences, Regolith, Grinding, 020901 industrial engineering & automation, Grind, 0103 physical sciences, Drill bit, Aerospace engineering, business, 010303 astronomy & astrophysics, Geology
Abstract

Successful sampling on the surface of asteroids is difficult because of their weightless environment and unknown material mechanical property. This work presents an asteroid sampler based on sweeping and grinding methods to improve the success rate of sampling. The sampler uses two brushes rotating clockwise and counter-clockwise to collect sample particles on the surface of asteroids. When encountering the hard rock or sample particles with large cohesion, the sampler adopts a drill bit to grind them to loose samples suitable for collecting by the brushes. The interaction between the brushes and the regolith is modeled and the sweeping mechanism is designed. A simple grinding mechanism is also designed. Numerical simulation and prototype experiments, at different parameters including blades number, rotational speed, and feeding speed of the brushes, mechanical property of the sample, and gravity, were conducted for validating the proposed methods. The 280g sampler prototype with 8 blades of brushes could collect about 19g regolith simulant in 25s in earth environment. The drill bits could work together with the brushes to improve the sampling efficiency through DEM simulation in case of large cohesion among sample particles. The sampler will be a good choice for installing into an asteroid rover in exploration.

Published
2019

41. Volt-VAR-Pressure Optimization of Integrated Energy Systems With Hydrogen Injection.

Author

Zhao, Pengfei, Lu, Xi, Cao, Zhidong, Gu, Chenghong, Ai, Qian, Liu, Hong, Bian, Yuankai, and Li, Shuangqi

Subjects
*HYDROGEN as fuel, *CONSTRAINT algorithms, *SEMIDEFINITE programming, *ROBUST optimization, *ECONOMIC efficiency
Abstract

Volt-VAR optimization (VVO) has been investigated extensively in power systems. However, under the era of integrated energy systems (IES), the growing interdependencies between different energy systems complicate traditional VVO. This is further hardened by incurred gas quality problems due to the hydrogen injection in IES, produced by widely applied power-to-gas (P2G) facilitates that couple between power and gas systems. This paper develops a two-stage volt-VAR-pressure optimization (VVPO) model for PV-penetrated IES to manage the variation of system voltages while managing gas quality indices. In addition to the traditional voltage regulating devices, P2G facilities, which can mitigate fluctuating PV output via converting the surplus generation into hydrogen, are also used for voltage management. A two-stage distributionally robust optimization (DRO) based on moment information is utilized to model PV uncertainty. A semidefinite programming model is formulated and finally solved by the constraint generation algorithm. A 33-bus-20-node IES is used to verify the effectiveness of the proposed VVPO on voltage management, ensured gas quality with high economic efficiency. The proposed VVPO is applicable to injecting other green gases into gas systems while ensuring power quality and enable system operators to provide low-cost but high-quality multi-energy to customers. [ABSTRACT FROM AUTHOR]

Published
2021
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42. Water-Energy Nexus Management for Power Systems.

Author

Zhao, Pengfei, Gu, Chenghong, Cao, Zhidong, Ai, Qian, Xiang, Yue, Ding, Tao, Lu, Xi, Chen, Xinlei, and Li, Shuangqi

Subjects
DECOMPOSITION method, ROBUST optimization, NETWORK hubs, WATER management, WIND power, VALUE at risk
Abstract

The water system management problem has been widely investigated. However, the interdependencies between water and energy systems are significant and the effective co-optimization is required considering strong interconnections. This paper proposes a two-stage distributionally robust operation model for integrated water-energy nexus systems including power, gas and water systems networked with energy hub systems at a distribution level considering wind uncertainty. The presence of wind power uncertainty inevitably leads to risks in the optimization model. Accordingly, a coherent risk measure, i.e., conditional value-at-risk, is combined with the optimization objective to determine risk-averse operation schemes. This two-stage mean-risk distributionally robust optimization is solved by Bender's decomposition method. Both the day-ahead and real-time operation cost are minimized with an optimal set of scheduling the multi-energy infrastructures. Case studies focus on investigating the strong interdependencies among the four interconnected energy systems. Numerical results validate the economic effectiveness of IES through optimally coordinating the multi-energy infrastructures. The proposed model can provide system operators a powerful two-stage operation scheme to minimise operation cost under water-energy nexus considering risk caused by renewable uncertainties, thus benefiting customers with lower utility bills. [ABSTRACT FROM AUTHOR]

Published
2021
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43. Absolute Calibration of the BDS-3 Receiver Based on Global Signal System

Author

Zhu Feng, Huang Lu-xi, and Li Xiaohui

Subjects
Global system, 010504 meteorology & atmospheric sciences, Computer science, Calibration (statistics), 01 natural sciences, Measure (mathematics), Signal, Absolute calibration, Power (physics), 010309 optics, Control theory, 0103 physical sciences, Phase relation, 0105 earth and related environmental sciences, Communication channel
Abstract

Since BeiDou Phase-III system has been launched, it is necessary to make receiver delay calibration of different signal systems in order to implement timing monitoring. A typical BDS-3 global system receiver was selected in this work. By analyzing its characteristics, we put forward the absolute calibration method, and used a simulator to measure the receiver delay with and without 1PPS input. The results show that channel delays are better than ±0.1ns, the inter-frequency deviation is less than 2ns without 1PPS input. While with 1PPS input, the receiver delay increases with the increasing of phase relation between 1PPS and 10MHz (TtP) accordingly in continuous test. Meanwhile, under power on-off test (also with 1PPS input), the receiver delay varies periodically. To verify the calibration results, homologous zero baseline test were performed. In addition, we analyzed the calibration accuracy. The combined uncertainty of B1, B2 and B3 is 1.24, 1.24 and 0.58, respectively.

Published
2018

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