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Landing control method of a lightweight four-legged landing and walking robot

《机械工程前沿（英文）》 2022年第17卷第4期 doi: 10.1007/s11465-022-0707-1

摘要： The prober with an immovable lander and a movable rover is commonly used to explore the Moon’s surface. The rover can complete the detection on relatively flat terrain of the lunar surface well, but its detection efficiency on deep craters and mountains is relatively low due to the difficulties of reaching such places. A lightweight four-legged landing and walking robot called “FLLWR” is designed in this study. It can take off and land repeatedly between any two sites wherever on deep craters, mountains or other challenging landforms that are difficult to reach by direct ground movement. The robot integrates the functions of a lander and a rover, including folding, deploying, repetitive landing, and walking. A landing control method via compliance control is proposed to solve the critical problem of impact energy dissipation to realize buffer landing. Repetitive landing experiments on a five-degree-of-freedom lunar gravity testing platform are performed. Under the landing conditions with a vertical velocity of 2.1 m/s and a loading weight of 140 kg, the torque safety margin is 10.3% and 16.7%, and the height safety margin is 36.4% and 50.1% for the cases with or without an additional horizontal disturbance velocity of 0.4 m/s, respectively. The study provides a novel insight into the next-generation lunar exploration equipment.

关键词： landing and walking robot lunar exploration buffer landing compliance control

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Modeling and analysis of landing collision dynamics for a shipborne helicopter

Dingxuan ZHAO, Haojie YANG, Carbone GIUSEPPE, Wenhang LI, Tao NI, Shuangji YAO

《机械工程前沿（英文）》 2021年第16卷第1期页码 151-162 doi: 10.1007/s11465-020-0617-z

摘要： A Lagrange dynamic model is established based on small-angle approximation to improve the simulation model for shipborne helicopter landing collision. To describe fuselage motion effectively, the proposed model considers ship motion, the interaction of the tires with the deck, and tire slippage. A mechanism of sliding motion is built, and a real-time reliability analysis of the algorithm is implemented to validate the proposed model. Numerical simulations are also conducted under different operation conditions. Results show that the proposed dynamic model can simulate the collision motion of helicopter landing in real time. Several suggestions for helicopter pilot landing are likewise provided.

关键词： shipborne helicopter landing model Lagrange equations dynamics validation

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天基发射与载人登月初探

张泽明,姜毅,傅德彬

《中国工程科学》 2006年第8卷第10期页码 37-41

摘要：

登月是载人航天向深空探测的延续，它与载人飞船工程相比，可靠性要求更高，工程规模更大，资金投入更多。结合国外登月历程和我国航天事业取得的重大成就，探讨了利用现有运载技术，分批次将登月飞船和航天员送入近地轨道，并在天基发射平台上进行组装发射，实现载人登月的设想；并就天基发射平台和天基发射方式进行了初步探讨。

关键词：登月天基发射发射平台登月轨道技术途径

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Estimation of fatigue damage of airplane landing gear

LIU Ke-ge, YAN Chu-liang, ZHANG Shu-ming

《机械工程前沿（英文）》 2006年第1卷第4期页码 424-428 doi: 10.1007/s11465-006-0051-x

摘要： Taking the main landing gears of fighter and transport airplanes as examples, the fatigue life was estimated by means of the Miner s rule and from the spectrum of the real measurements. The computed results show that the landing damage to the fighter and transport airplanes is 75% and 60% of the total damage, and the damage caused by the landing stroke is 40% of the landing-gear damage. The fatigue damage properties can provide important information for reliable designing and the structural optimization.

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Planar jumping with stable landing through foot orientation design and ankle joint control

Qilong YUAN, I-Ming CHEN

《机械工程前沿（英文）》 2012年第7卷第2期页码 100-108 doi: 10.1007/s11465-012-0318-3

摘要：

This paper introduces a method to generate the planar jumping motion for biped robot. In this work, through determining the upper body posture trajectory in the flight phase, the foot landing posture is made to be flat while landing. Together with properly designing the trajectory for local center of gravity and the foot landing velocity, the soft landing trajectory is generated. A controller on the ankle joint is added to avoid significant impact with the ground and stabilize the robot after landing. Jumping motion with stable landing is achieved in a dynamic simulation environment based on this method.

关键词： biped jumping stable landing control jumping motion generation

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中国进入空间能力的现状与展望

龙乐豪,王小军,果琳丽

《中国工程科学》 2006年第8卷第11期页码 25-28

摘要：

总结了国外航天运输系统的现状及发展趋势；对比分析了我国长征系列运载火箭的现状和差距；提出了增强我国进入空间能力的五个发展方向，即改进现役运载火箭、研制新一代运载火箭系列、发展快速机动发射小型运载火箭、具备载人登月及深空运输能力、探索重复使用运输技术。

关键词：航天长征火箭家族载人登月重复使用运载器

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行星表面动力着陆自主制导方法综述 Review

宋征宇1,5,王聪2,Stephan THEIL3,David SEELBINDER3,Marco SAGLIANO3,刘新福4,邵之江5

《信息与电子工程前沿（英文）》 2020年第21卷第5期页码 649-808 doi: 10.1631/FITEE.1900458

摘要：本文总结了天体表面精确软着陆的自主制导方法。首先回顾了动力下降制导方法的发展，重点介绍了其在约束处理和提升计算效率方面的贡献。随着对可重复使用运载器需求的不断增加，以及太空探索带来更多的科学回报，定点软着陆成为一项基本要求。不同于过去任务中公里级的着陆精度，未来行星着陆器在满足全部速度和姿态约束条件下，着陆位置精度要达到10米级，这项任务的困难引起学者对自主制导方法的兴趣。本文讨论了动力下降阶段一般性的3自由度和6自由度优化问题，并对比月球、火星和地球3种典型着陆场景的特点。在此基础上，通过比较解析制导方法、数值优化算法和基于学习的方法，详细阐述自主制导方法的特点和适应性，并讨论非凸问题的凸化处理和求解策略。随后提出自主制导方法工程应用的3个关键问题：物理可行性、模型精度和实时性。最后，简要介绍各国航天组织（包括美国、中国、法国、德国和日本）研发的垂直起降验证飞行器，以及目前在验证飞行器上开展的制导方法试验工作。

关键词：自主制导方法；定点软着陆；动力下降；非线性规划

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基于Watt连杆的可重复使用运载火箭腿式可展开着陆机构——原理、原型设计和实验验证 Article

于海涛, 田保林, 闫振, 高海波, 张宏剑, 吴会强, 王英超, 石玉红, 邓宗全

《工程（英文）》 2023年第20卷第1期页码 120-133 doi: 10.1016/j.eng.2022.05.015

摘要：

可重复使用运载火箭是降低太空运输成本的一种新途径。着陆机构是可重复使用运载火箭的重要组成部分，起到着陆支撑和吸收冲击的作用。本文提出了一种新型的可展开着陆机构（LDLM）。采用Watt-II型六杆机构，利用连杆变分法得到优选构型。本文建立了多目标优化范式，使得可展开着陆机构具有着陆支撑区域大、轻量化、连杆内力合理等优点，在此基础上，利用多目标遗传算法（NSGA-II）进化算法得到了可展开式着陆机构设计的最优尺寸参数。本文研制了全功能可重复使用运载火箭缩比样机，通过集成重力控制的展开方案促进展开动作，避免全范围驱动，采用双重锁紧机构提高展开状态时结构的可靠性，采用多级铝蜂窝缓冲器提供可靠的减震性能。实验结果表明，所提出的可展开式着陆机构能够提供快速平稳的展开（持续时间小于1.5 s），且对舱体的姿态扰动较小（偏航和俯仰波动小于6°）。此外，该机构在0.2 m自由落体测试中提供了足够的冲击衰减（加速度峰值小于10g）。所提出的可展开着陆机构可作为未来可重复使用运载火箭潜在的腿式起落架替代方案。

关键词：可重复使用运载火箭（RLV）可展开机构优化设计

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Standard model of knowledge representation

Wensheng YIN

《机械工程前沿（英文）》 2016年第11卷第3期页码 275-288 doi: 10.1007/s11465-016-0372-3

摘要：

Knowledge representation is the core of artificial intelligence research. Knowledge representation methods include predicate logic, semantic network, computer programming language, database, mathematical model, graphics language, natural language, etc. To establish the intrinsic link between various knowledge representation methods, a unified knowledge representation model is necessary. According to ontology, system theory, and control theory, a standard model of knowledge representation that reflects the change of the objective world is proposed. The model is composed of input, processing, and output. This knowledge representation method is not a contradiction to the traditional knowledge representation method. It can express knowledge in terms of multivariate and multidimensional. It can also express process knowledge, and at the same time, it has a strong ability to solve problems. In addition, the standard model of knowledge representation provides a way to solve problems of non-precision and inconsistent knowledge.

关键词： knowledge representation standard model ontology system theory control theory multidimensional representation

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受限空间火灾模型研究进展

郑昕,袁宏永

《中国工程科学》 2004年第6卷第3期页码 68-74

摘要：

火灾模型是从工程科学的角度出发，分析研究火灾的发生、发展，烟气蔓延以及火灾对周围环境诸如建筑设备、森林植被及大气环境等影响的数学模型。介绍了广泛应用于建筑物内部受限空间的场、区域、网模型以及经验模型的理论思想与数学方程，分析了4种模型在相应环境下应用的合理性，并对火灾模型的发展做出了展望。

关键词：受限空间场模型区域模型网模型场区网模型经验模型

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Elevated temperature creep model of parallel wire strands

《结构与土木工程前沿（英文）》页码 1060-1071 doi: 10.1007/s11709-023-0981-y

摘要： Parallel wire strands (PWSs), which are widely used in prestressed steel structures, are typically in high-stress states. Under fire conditions, significant creep effects occur, reducing the prestress and influencing the mechanical behavior of PWSs. As there is no existing approach to analyze their creep behavior, this study experimentally investigated the elevated temperature creep model of PWSs. A charge-coupled camera system was incorporated to accurately obtain the deformation of the specimen during the elevated temperature creep test. It was concluded that the temperature level had a more significant effect on the creep strain than the stress level, and 450 °C was the key segment point where the creep rate varied significantly. By comparing the elevated temperature creep test results for PWSs and steel strands, it was found that the creep strain of PWSs was lower than that of steel strands at the same temperature and stress levels. The parameters in the general empirical formula, the Bailey–Norton model, and the composite time-hardening model were fitted based on the experimental results. By evaluating the accuracy and form of the models, the composite time-hardening model, which can simultaneously consider temperature, stress, and time, is recommended for use in the fire-resistance design of pre-tensioned structures with PWSs.

关键词： parallel wire strands experimental study elevated temperature creep model

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Impact of crude distillation unit model accuracy on refinery production planning

Gang FU, Pedro A. Castillo CASTILLO, Vladimir MAHALEC

《工程管理前沿（英文）》 2018年第5卷第2期页码 195-201 doi: 10.15302/J-FEM-2017052

摘要： In this work, we examine the impact of crude distillation unit (CDU) model errors on the results of refinery-wide optimization for production planning or feedstock selection. We compare the swing cut+ bias CDU model with a recently developed hybrid CDU model (Fu et al., 2016). The hybrid CDU model computes material and energy balances, as well as product true boiling point (TBP) curves and bulk properties (e.g., sulfur % and cetane index, and other properties). Product TBP curves are predicted with an average error of 0.5% against rigorous simulation curves. Case studies of optimal operation computed using a planning model that is based on the swing cut+ bias CDU model and using a planning model that incorporates the hybrid CDU model are presented. Our results show that significant economic benefits can be obtained using accurate CDU models in refinery production planning.

关键词： impact of model accuracy on production planning swing cut+ bias CDU model hybrid CDU model refinery feedstock selection optimization optimization of refinery operation

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Test-driven verification/validation of model transformations

László LENGYEL,Hassan CHARAF

《信息与电子工程前沿（英文）》 2015年第16卷第2期页码 85-97 doi: 10.1631/FITEE.1400111

摘要： Why is it important to verify/validate model transformations? The motivation is to improve the quality of the transformations, and therefore the quality of the generated software artifacts. Verified/validated model transformations make it possible to ensure certain properties of the generated software artifacts. In this way, verification/validation methods can guarantee different requirements stated by the actual domain against the generated/modified/optimized software products. For example, a verified/validated model transformation can ensure the preservation of certain properties during the model-to-model transformation. This paper emphasizes the necessity of methods that make model transformation verified/validated, discusses the different scenarios of model transformation verification and validation, and introduces the principles of a novel test-driven method for verifying/validating model transformations. We provide a solution that makes it possible to automatically generate test input models for model transformations. Furthermore, we collect and discuss the actual open issues in the field of verification/validation of model transformations.

关键词： Graph rewriting based model transformations Verification/validation Test-driven verification

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Digital twin-assisted gearbox dynamic model updating toward fault diagnosis

《机械工程前沿（英文）》 2023年第18卷第2期 doi: 10.1007/s11465-023-0748-0

摘要： One of the core challenges of intelligent fault diagnosis is that the diagnosis model requires numerous labeled training datasets to achieve satisfactory performance. Generating training data using a virtual model is a potential solution for addressing such a problem, and the construction of a high-fidelity virtual model is fundamental and critical for data generation. In this study, a digital twin-assisted dynamic model updating method for fault diagnosis is thus proposed to improve the fidelity and reliability of a virtual model, which can enhance the generated data quality. First, a virtual model is established to mirror the vibration response of a physical entity using a dynamic modeling method. Second, the modeling method is validated through a frequency analysis of the generated signal. Then, based on the signal similarity indicator, a physical–virtual signal interaction method is proposed to dynamically update the virtual model in which parameter sensitivity analysis, surrogate technique, and optimization algorithm are applied to increase the efficiency during the model updating. Finally, the proposed method is successfully applied to the dynamic model updating of a single-stage helical gearbox; the virtual data generated by this model can be used for gear fault diagnosis.

关键词： digital twin gearbox model construction model updating physical–virtual interaction

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Estimation of composite load model with aggregate induction motor dynamic load for an isolated hybrid

Nitin Kumar SAXENA,Ashwani Kumar SHARMA

《能源前沿（英文）》 2015年第9卷第4期页码 472-485 doi: 10.1007/s11708-015-0373-7

摘要： It is well recognized that the voltage stability of a power system is affected by the load model and hence, to effectively analyze the reactive power compensation of an isolated hybrid wind-diesel based power system, the loads need to be considered along with the generators in a transient analysis. This paper gives a detailed mathematical modeling to compute the reactive power response with small voltage perturbation for composite load. The composite load is a combination of the static and dynamic load model. To develop this composite load model, the exponential load is used as a static load model and induction motors (IMs) are used as a dynamic load model. To analyze the dynamics of IM load, the fifth, third and first order model of IM are formulated and compared using differential equations solver in Matlab coding. Since the decentralized areas have many small consumers which may consist large numbers of IMs of small rating, it is not realistic to model either a single large rating unit or all small rating IMs together that are placed in the system. In place of using a single large rating IM, a group of motors are considered and then the aggregate model of IM is developed using the law of energy conservation. This aggregate model is used as a dynamic load model. For different simulation studies, especially in the area of voltage stability with reactive power compensation of an isolated hybrid power system, the transfer function of the composite load is required. The transfer function of the composite load is derived in this paper by successive derivation for the exponential model of static load and for the fifth and third order IM dynamic load model using state space model.

关键词： isolated hybrid power system (IHPS) composite load model static load dynamic load induction motor load model aggregate load