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Effects of ignition voltage and electrode structure on electric ignition and combustion characteristics of Ammonium Dinitramide(ADN)-based liquid propellants in electric ignition mode in inert gas environment

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Chinese Journal of Aeronautics 2024年第4期37卷 229-242页

作者： Lei LI Guoxiu LI Hongmeng LI Zhaopu YAO Tao ZHANG Jinze WU Shuo ZHANG School of Mechanical Electronic and Control EngineeringBeijing Jiaotong UniversityBeijing 100044China Beijing Institute of Control Engineering Beijing 100190China

Hydrazine is toxic and carcinogenic, which greatly increases the difficulty of application and no longer meets the needs of green aerospace. As a green propellant, the Ammonium Dinitramide(ADN)-based liquid propellant has the advantages of higher specific impulse, being non-toxic,pollution-free, and easy storage. However, an ADN-based space engine in orbit has exposed the problems of high-temperature deactivation of catalysts and cold-start failure. An active ignition technology—electric ignition technology was explored in this paper to break through the technical bottleneck of catalyst deactivation and the inability to a cold start. An experimental system of a constant-volume combustor for the ADN-based liquid propellant based on the electric ignition method was established. The electric ignition and combustion characteristics of the ADN-based liquid propellant in a volume combustor with an electric ignition method were studied. The influencing mechanisms of the ignition voltage and the electrode structure on the electric ignition characteristics of the ADN-based liquid propellant were investigated. An elevation of the ignition voltage could facilitate the ignition process of the ADN-based liquid propellant, curtail electric energy input and heating effect, while exerting an adverse impact on the combustion process of the *** increase in the ignition voltage enhanced the ignition process of the propellant while simultaneously suppressing its combustion process when utilizing mesh electrodes. Compared to the strip electrodes, the mesh electrodes increased the contact area between the electrodes and the propellant,increased the electric energy input power in the electric ignition process, and reduced the ignition delay time. The mesh electrodes could promote the combustion process of the propellant to a certain extent.

关键词： ADN-based liquid propellant Resistive ignition Electrical ignition characteristic Combustion Inert gas

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Modified Three-Loop Autopilot for Acceleration control Performance Improvement of a Canard-controlled Aircraft

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Transactions of the Korean Institute of Electrical Engineers 2024年第7期73卷 1220-1231页

作者： Han, Kwang-Hee Han, Jieun Whang, Ick-Ho Ra, Won-Sang School of Mechanical and Control Engineering Handong Global University Korea Republic of Department of Mechanical and Control Engineering Handong Global University Korea Republic of

This paper proposes a new autopilot topology with its optimal design methodology for canard-controlled unmanned aerial vehicles(UAVs). While the traditional three-loop autopilot has been considered as a rule of thumb to control a tail-controlled UAV, it is questionable whether this topology also becomes one of the best choices for UAVs with other wing configurations. To identify a probable improvement of the existing approach, the topological property of the conventional three-loop autopilot is investigated. As a result, it is shown that the three-loop autopilot consists of a full-state feedback controller with an angle-of-attack estimator as well as an integral compensator in its feedforward path. Based on this observation, a modified three-loop autopilot is suggested by replacing the integral compensator with the proportional-integral one to improve the acceleration tracking performance. The control gains of our autopilot are designed by solving the optimal output feedback control problem. To cope with the lack of stability margin due to un-modeled actuator dynamics, the weighting matrix associated with the cost function of the problem is systematically chosen to guarantee the desired phase margin and the gain cross-over frequency. Simulation results confirm that the proposed method shows better performance for canard-controlled UAVs than the existing topology. Copyright © The Korean Institute of Electrical Engineers.

关键词： Topology

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Ultrathin two-dimensional medium-entropy oxide as a highly efficient and stable electrocatalyst for oxygen evolution reaction

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Nano Research 2024年第4期17卷 2555-2562页

作者： Guangyuan Yan Tianlu Wang Biwei Zhao Wenjing Gao Tong Wu Liming Ou School of Mechanical Electronic and Control EngineeringBeijing Jiaotong UniversityBeijing 100044China

Medium-entropy oxides(MEOs)with broad compositional tunability and entropy-driven structural stability,are receiving booming attention as a promising candidate for oxygen evolution reaction(OER)***,ultrathin two-dimensional(2D)nanostructure offers extremely large specific surface area and is therefore considered to be an ideal catalyst ***,it remains a grant challenge to synthesize ultrathin 2D MEOs due to distinct nucleation and growth kinetics of constituent multimetallic elements in 2D anisotropic *** this work,an ultrathin 2D MEO(MnFeCoNi)O was successfully synthesized by a facile and low-temperature ionic layer epitaxy *** from multi-metal synergistic effects within ultrathin 2D nanostructure,this 2D MEO(MnFeCoNi)O revealed excellent OER electrocatalytic performance with a quite low overpotential of 117 mV at 10 mA·cm^(-2) and an impressive stability for 120 h continuous operation with only 6.9%***,the extremely high mass activity(5584.3 A·g^(-1))was three orders of magnitude higher than benchmark RuO_(2)(3.4 A·g^(-1))at the same overpotential of 117 *** work opens up a new avenue for developing highly efficient and stable electrocatalysts by creating 2D nanostructured MEOs.

关键词： medium-entropy oxide two-dimensional nanomaterials ionic layer epitaxy oxygen evolution reaction electrocatalysis

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Multimode Design and Analysis of an Integrated Leg-Arm Quadruped Robot with Deployable Characteristics

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Chinese Journal of mechanical engineering 2024年第3期37卷 41-61页

作者： Fuqun Zhao Yifan Wu Xinhua Yang Xilun Ding Kun Xu Sheng Guo Xiaodong Jin School of Mechanical Engineering and Automation Beihang UniversityBeijing 100191China School of Mechanical Electronic and Control EngineeringBeijing Jiaotong UniversityBeijing 100044China

To improve locomotion and operation integration, this paper presents an integrated leg-arm quadruped robot(ILQR) that has a reconfigurable joint. First, the reconfigurable joint is designed and assembled at the end of the legarm chain. When the robot performs a task, reconfigurable configuration and mode switching can be achieved using this joint. In contrast from traditional quadruped robots, this robot can stack in a designated area to optimize the occupied volume in a nonworking state. Kinematics modeling and dynamics modeling are established to evaluate the mechanical properties for multiple modes. All working modes of the robot are classified, which can be defined as deployable mode, locomotion mode and operation mode. Based on the stability margin and mechanical modeling, switching analysis and evaluation between each mode is carried out. Finally, the prototype experimental results verify the function realization and switching stability of multimode and provide a design method to integrate and perform multimode for quadruped robots with deployable characteristics.

关键词： Quadruped robot Multimode design Mode switching Locomotion Operation

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Study of Source-load Interaction in Demand Response Considering the Potential of Flexible Load Dispatch

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Chinese Journal of Electrical engineering 2024年第4期10卷 141-151页

作者： Wenqi Ge Xiaotong Wang School of Control and Mechanical Engineering Tianjin Chengjian UniversityTianjin 300380China

With the further deepening of power market reform, flexible loads have become the focus of attention for power supply and demand. In the context of new power systems, it is necessary to consider the potential of flexible load dispatch on the side of the customer for power demand response research. Based on this, a typical flexible load is selected in the community, and an economic model with minimum cost is established as the objective function. This model is used to regulate the power load curve and achieve valley filling and peak shaving. Additionally, considering different weather conditions, the calculation example analyzes the effect of flexible load participation in regulation under various environments and combines the time-of-use tariff for dispatch. The results can flexibly and effectively guide users to participate in demand response, reduce economic input on the user side, and meet the higher requirements of flexible demand-side regulation resources to support the safe operation of the power system, which has certain application potential and economic value.

关键词： Demand response economy flexible load scheduling

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Low-temperature chemistry in plasma-driven ammonia oxidative pyrolysis

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Green Energy & Environment 2024年第9期9卷 1477-1488页

作者： Mingming Zhang Qi Chen Guangzhao Zhou Jintao Sun He Lin School of Mechanical Electronic and Control EngineeringBeijing Jiaotong UniversityBeijing100044China School of Mechanical Engineering Shanghai Jiao Tong UniversityShanghai200240China

Ammonia is gaining increasing attention as a green alternative fuel for achieving large-scale carbon emission reduction. Despite its potential technical prospects, the harsh ignition conditions and slow flame propagation speed of ammonia pose significant challenges to its application in engines. Non-equilibrium plasma has been identified as a promising method, but current research on plasma-enhanced ammonia combustion is limited and primarily focuses on ignition characteristics revealed by kinetic models. In this study, low-temperature and low-pressure chemistry in plasma-assisted ammonia oxidative pyrolysis is investigated by integrated studies of steady-state GC measurements and mathematical simulation. The detailed kinetic mechanism of NH_(3) decomposition in plasma-driven Ar/NH_(3) and Ar/NH_(3)/O_(2) mixtures has been developed. The numerical model has good agreements with the experimental measurements in NH_(3)/O_(2) consumption and N_(2)/H_(2) generation, which demonstrates the rationality of modelling. Based on the modelling results, species density profiles, path flux and sensitivity analysis for the key plasmaproduced species such as NH_(2), NH, H_(2), OH, H, O, O(^(1)D), O_(2)(a^(1)△_(g)), O_(2)(b^(1)∑_(g)^(+)), Ar^(*), H^(-), Ar^(+), NH_(3)^(+), O_(2)^(-) in the discharge and afterglow are analyzed in detail to illustrate the effectiveness of the active species on NH_(3) excitation and decomposition at low temperature and relatively higher E/N values. The results revealed that NH_(2), NH, H as well as H_(2) are primarily generated through the electron collision reactions e + NH_(3)→ e + NH_(2)+ H, e + NH_(3)→ e + NH + H_(2) and the excited-argon collision reaction Ar^(*) + NH_(3)+ H → Ar + NH_(2)+ 2H, which will then react with highly reactive oxidative species such as O_(2)^(*), O^(*), O, OH, and O_(2) to produce stable products of NOx and H_(2)O. NH_(3)→ NH is found a specific pathway for NH_(3) consumption with plasma assistance, which further highlig

关键词： Non-equilibrium plasma Ammonia fuel Oxidative pyrolysis Pathway flux analysis Sensitivity analysis

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Topological Structure Design and Obstacle-climbing Capability Analysis of a Lizard-inspired Torso-leg-foot Biomimetic Robot

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Journal of Bionic engineering 2025年第1期22卷 65-82页

作者： Yuting Du Yan-an Yao Qiang Ruan Wenbo Mi School of Mechanical Electronic and Control EngineeringBeijing Jiaotong UniversityBeijing100044China Beijing Institute of Aerospace Control Devices Beijing100039China

Lizards are one of the most primitive reptiles in existence,with special limb structures that enable them to move quickly across diverse and complex terrains such as rock piles,shallow shoals,and deserts.A thorough exploration was conducted on the biomimetic mechanism and ground-touching mechanism of lizard limbs from both micro and macro *** by the intricate torso and limb configurations of lizards,a novel Torso-leg-foot biomimetic robot has been conceptualized based on the design of the Big-Foot *** robot integrates a Torso-leg-foot system,featuring a parallel torso biomimetic structure with a 2-SPR/UPU/UPR(P)*** utilizes the theory of finite screws to articulate the instantaneous movements of the parallel torso,and the inverse kinematics of this mechanism have been *** reachable workspace of the 2-SPR/UPU/UPR parallel mechanism using FIS theory,which is closely related to the climbing height of the robot.A comprehensive dimension synthesis was conducted on the leg-foot system,and the adoption of the three-pair rod drive method was determined by investigating its Variable Rotating Velocity Characteristics(VRVC).Simulation tests have shown that with an integrated torso,the robot can climb vertical obstacles up to 600 mm in *** experimental tests of climbing steps and slopes using physical prototypes have confirmed the robot's obstacle-crossing *** potential applications of this Torso-leg-foot biomimetic robot is to carry heavy objects across obstacles to perform tasks such as planetary exploration and disaster relief.

关键词： Torso-leg-foot Lizard biomimetics Topological structure Variable Rotating Velocity Characteristics(VRVC) Obstacle-climbing capability

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F-doping effects on microstructure and electrochemical performance of cathode material Li_(1.2)Mn_(0.54)Ni_(0.13)Co_(0.13)O_(2)

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Particuology 2024年第12期95卷 82-91页

作者： Xiaoqian Sun Yunhui Du Weiyi Zhang Mengjiao Jin Ruiang Fan Peng Zhang School of Mechanical Electronic and Control EngineeringBeijing Jiaotong UniversityBeijing10004China School of Department of Mechanical Engineering Stanford UniversityStanfordCA94305United States

Lithium-rich manganese-based(Li-rich Mn-based)cathode materials possess high specific capacity,low self-discharge rate and steady working voltage,but cycle performance and rate performance need to be further *** this study,cathode materials Li_(1.2)Mn_(0.54)Ni_(0.13)Co_(0.13)O_(2-x)F_(x)(x=0,0.02,0.05,0.08)are synthesized by the co-precipitation method with the two-step calcination *** the F-doping effects on the microstructure and the electrochemical performance are investigated in the cathode materials Li_(1.2)Mn_(0.54)Ni_(0.13)Co_(0.13)O_(2).The results indicate that among all the F-doped cathode materials,the crystal lattice parameters are increased,order degree and stability of the layered structure are *** for x=0.05,cathode material Li_(1.2)Mn_(0.54)Ni_(0.13)Co_(0.13)O_(1.95)F_(0.05)(LMO-F_(0.05))shows the best cycle performance and rate performance with its capacity retention rate 87.7%after 100 cycles at 0.2 C and discharge capacity 117 mAh g−1 at 5 C high *** can be seen that F doping is a simple and crucial strategy to promote the Li ion diffusion and develop high performance layered cathode materials.

关键词： F-doped Li-rich Mn-Based cathode material Microstructure Cycling performance Rate performance

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CCHP-Type Micro-Grid Scheduling Optimization Based on Improved Multi-Objective Grey Wolf Optimizer

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Energy engineering 2025年第3期122卷 1137-1151页

作者： Yu Zhang Sheng Wang Fanming Zeng Yijie Lin College of Mechanical and Control Engineering Guilin University of TechnologyGuilin541006China

With the development of renewable energy technologies such as photovoltaics and wind power,it has become a research hotspot to improve the consumption rate of new energy and reduce energy costs through algorithm *** reduce the operational costs of micro-grid systems and the energy abandonment rate of renewable energy,while simultaneously enhancing user satisfaction on the demand side,this paper introduces an improvedmultiobjective Grey Wolf Optimizer based on Cauchy *** proposed approach incorporates a Cauchy variation strategy during the optimizer’s search phase to expand its exploration range and minimize the likelihood of becoming trapped in local *** the same time,adoptingmultiple energy storage methods to improve the consumption rate of renewable ***,under different energy balance orders,themulti-objective particle swarmalgorithm,multi-objective grey wolf optimizer,and Cauchy’s variant of the improvedmulti-objective grey wolf optimizer are used for example simulation,solving the Pareto solution set of the model and *** analysis of the results reveals that,compared to the original optimizer,the improved optimizer decreases the daily cost by approximately 100 yuan,and reduces the energy abandonment rate to ***,it enhances user satisfaction and ensures the stable operation of the micro-grid.

关键词： Multi-objective optimization algorithm hybrid energy storage micro-grid CCHP

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Asymptotically Unbiased Linear Kalman Filter for Radar Tracking With Polar Measurements

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Journal of Institute of control, Robotics and Systems 2024年第3期30卷 267-275页

作者： Jung, Boyoung Whang, Ick-Ho Ra, Won-Sang School of Mechanical and Control Engineering Handong Global University Korea Republic of

This study proposes a new linear state estimation filter for radar target tracking. Unlike the conventional converted measurement technique, target motion and radar measurements are modeled in mixed Cartesian coordinate systems. Considering the coordinate transformation relationship between radar measurements and state variables, radar target tracking is described as a state estimation problem for a linear measurement model. This model is useful in practice because it guarantees the whiteness of the measurement noise sequence and the unbiasedness of the target state estimator. Based on this observation, the design of a tracking filter is described as a stochastic minimization problem of an indefinite quadratic form linked to a linear time-varying system whose measurement matrix includes the random coordinate transform uncertainty. The resulting solution almost surely converges to the true state, even when an uncertain coordinate transform matrix is used. Computer simulations show that the proposed filter performs better and more consistently than the existing methods regarding target tracking performance. © ICROS 2024.

关键词： Radar measurement

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