Accurate motion prediction of free-tumbling satellites is crucial for the success of capture operations.This paper proposes a two-step method to estimate the motion states and parameters of such satellites,thereby ena...Accurate motion prediction of free-tumbling satellites is crucial for the success of capture operations.This paper proposes a two-step method to estimate the motion states and parameters of such satellites,thereby enabling precise long-term motion prediction.This paper begins with a measurement of the system's degree of observability,quantified through the Empirical Observability Gramian(EOG).Based on this measurement,a batch processing algorithm is first employed to estimate the satellite's constant parameters offline.Subsequently,an online filtering algorithm,utilizing a minimal state set,fine-tunes these parameters and estimates the motion states in real time.This integrated approach significantly enhances both convergence properties and estimation accuracy,particularly for systems with poor observability.Utilizing the predicted long-term motion of the satellite,a composite evaluation metric is formulated to identify the optimal capture point and moment.The base pose of the space robot is then adjusted to ensure that the optimal capture point lies within the manipulator's dexterous workspace,which is determined through a pre-constructed capability map.The effectiveness of the proposed method is demonstrated through both simulation and experimental results.展开更多
Lithium-sulfur batteries(LSBs)are considered as the promising solution to replace conventional lithium-ion batteries due to satisfactory energy density.In recent times,the LSBs field has been found to face some diffic...Lithium-sulfur batteries(LSBs)are considered as the promising solution to replace conventional lithium-ion batteries due to satisfactory energy density.In recent times,the LSBs field has been found to face some difficulties in exploring practical applications in which cycling stability and cycle life are awful owing to the shuttling effect of lithium polysulfides(LiPSs)and low sulfur utilization.In this work,by synthesizing Co_(3)Se_(4) nanoparticles onto N-doped carbon(NC)polyhedra interconnected with carbon nanotubes(CNTs),NC@Co_(3)Se_(4)/CNTs is proposed as a multifunctional sulfur carrier.The Co_(3)Se_(4) nanoparticles fleetly catalyze the conversion of LiPSs and availably immobilize LiPSs.Meanwhile,the NC polyhedral skeleton enhances the electronic conductivity of active sulfur,while the CNTs facilitate Li+diffusion and supply a mass of conductive channels.Density-functional theory(DFT)calculations demonstrate the relevant mechanisms.That is to say,the NC@Co_(3)Se_(4)/CNTs benefit from the synergistic effect of Co_(3)Se_(4) nanoparticles(highly catalytic ability and strong adsorbability for LiPSs)and the special carbonaceous structure,rapidly converting LiPSs and inhibiting the shuttle of LiPSs.Therefore,lithium-sulfur battery assembled with S/NC@Co_(3)Se_(4)/CNTs cathode as well as nitrogen and sulfur co-doped carbon-coated polypropylene(N,S-C/PP)separator possesses a high initial discharge capacity of 1413 mAh·g-1 at 0.12C and persistently circulates for 1000 cycles at 1C with a capacity attenuation rate per cycle of 0.034%.This work provides a realistic idea for the use of transition metal selenide in the field of high-performance LSBs.展开更多
Reusable and flexible capturing of space debris is highly required in future aerospace technologies.A tendon-actuated flexible robotic arm is therefore proposed for capturing floating targets in this paper.Firstly,an ...Reusable and flexible capturing of space debris is highly required in future aerospace technologies.A tendon-actuated flexible robotic arm is therefore proposed for capturing floating targets in this paper.Firstly,an accurate dynamic model of the flexible robotic arm is established by using the absolute nodal coordinate formulation(ANCF)in the framework of the arbitrary Lagrangian-Eulerian(ALE)description and the natural coordinate formulation(NCF).The contact and self-contact dynamics of the flexible robotic arm when bending and grasping an object are considered via a fast contact detection approach.Then,the dynamic simulations of the flexible robotic arm for capturing floating targets are carried out to study the influence of the position,size,and mass of the target object on the grasping performance.Finally,a principle prototype of the tendon-actuated flexible robotic arm is manufactured to validate the dynamic model.The corresponding grasping experiments for objects of various shapes are also conducted to illustrate the excellent performance of the flexible robotic arm.展开更多
随着清洁可再生能源的不断发展,利用洋流能为水下微型无线传感器提供电能已成为研究热点。水下涡激振动能量俘获系统是一种在浅海低流速条件下利用涡激振动效应俘获洋流能的发电装置。本文将非线性恢复力、单向轴承及齿轮齿条机构与振...随着清洁可再生能源的不断发展,利用洋流能为水下微型无线传感器提供电能已成为研究热点。水下涡激振动能量俘获系统是一种在浅海低流速条件下利用涡激振动效应俘获洋流能的发电装置。本文将非线性恢复力、单向轴承及齿轮齿条机构与振动钝体结合,提出一种新型基于洋流能的涡激振动能量俘获系统。采用Van der Pol方程描述流体和钝体间的耦合效应,建立系统流-固-电耦合动力学方程。对系统进行稳定性分析,得到系统在单稳、双稳及三稳态情况下的参数数值范围,将3种稳态下系统的振幅比进行对比,发现系统处于三稳态时具有较强的发电优势。借助数值仿真,通过钝体振动的时域图、相图、分岔图及庞加莱截面详细研究流体参数(水流流速)和结构参数(质量比和阻尼比)对系统位移响应的影响,并分析单向轴承对传动轴转速的影响。分析质量比和阻尼比对发电功率的影响。结果表明,三稳态系统拥有非常丰富的非线性动力学行为,出现混沌运动、多周期运动及准周期运动,阻尼比的变化主要影响发电功率的峰值,而质量比的变化主要影响涡激振动的共振区间范围。展开更多
When the space robot captures a floating target, contact impact occurs inevitably and frequently between the manipulator hand and the target, which seriously impacts the position and attitude of the robot and grasping...When the space robot captures a floating target, contact impact occurs inevitably and frequently between the manipulator hand and the target, which seriously impacts the position and attitude of the robot and grasping security. ＂Dynamic grasping area＂ is introduced to describe the collision process of manipulator grasping target, and grasping area control equation is established. By analyzing the impact of grasping control parameters, base and target mass on the grasping process and combining the life experience, it is found that if the product of speed control parameter and dB adjustment parameter is close to but smaller than the minimum grasping speed, collision impact in the grasping process could be reduced greatly, and then an ideal grasping strategy is proposed. Simulation results indicate that during the same period, the strategy grasping is superior to the accelerating grasping, in that the amplitude of impact force is reduced to 20%, and the attitude control torque is reduced to 15%, and the impact on the robot is eliminated significantly. The results would have important academic value and engineering significance.展开更多
【目的】考虑系统清洁低碳的前提下,综合能源系统中能源产品定价与市场用户的经济利益和能源运营商的盈利能力密切相关。为此,对含电转气-碳捕集电厂(power to gas-carbon capture power plant,P2G-CCPP)的综合能源系统(integrated ener...【目的】考虑系统清洁低碳的前提下,综合能源系统中能源产品定价与市场用户的经济利益和能源运营商的盈利能力密切相关。为此,对含电转气-碳捕集电厂(power to gas-carbon capture power plant,P2G-CCPP)的综合能源系统(integrated energy system,IES)进行㶲经济分析。【方法】从㶲视角出发,兼顾能量的量与质,针对不同能流进行㶲值计算,建立㶲流计算子模型。将系统低碳经济性引入㶲经济分析中,将碳排放权交易成本、碳捕集能耗成本及碳封存成本纳入非能量成本中,建立㶲经济成本分摊子模型。相较于传统定价方法,考虑了碳成本及能量品位差异对系统冷热电单位㶲成本的影响,体现优质优价原则。【结果】仿真算例表明引入P2G-CCPP联动系统能够提高系统低碳减排能力,实现成本合理分摊。【结论】含P2G-CCPP机组的综合能源系统能够有效削减系统总成本及冷热电单位成本,增强了碳利用和燃气生产消费的节能减排途径,具有显著的经济及社会效益。展开更多
基金supported by the National Natural Science Foundation of China(Nos.62403171,T2388101)。
文摘Accurate motion prediction of free-tumbling satellites is crucial for the success of capture operations.This paper proposes a two-step method to estimate the motion states and parameters of such satellites,thereby enabling precise long-term motion prediction.This paper begins with a measurement of the system's degree of observability,quantified through the Empirical Observability Gramian(EOG).Based on this measurement,a batch processing algorithm is first employed to estimate the satellite's constant parameters offline.Subsequently,an online filtering algorithm,utilizing a minimal state set,fine-tunes these parameters and estimates the motion states in real time.This integrated approach significantly enhances both convergence properties and estimation accuracy,particularly for systems with poor observability.Utilizing the predicted long-term motion of the satellite,a composite evaluation metric is formulated to identify the optimal capture point and moment.The base pose of the space robot is then adjusted to ensure that the optimal capture point lies within the manipulator's dexterous workspace,which is determined through a pre-constructed capability map.The effectiveness of the proposed method is demonstrated through both simulation and experimental results.
基金supported by the National Natural Science Foundation of China(Nos.52130101 and 52271217)the Project of Science and Technology Development Plan of Jilin Province in China(Nos.20210402058GH,20220201114GX).
文摘Lithium-sulfur batteries(LSBs)are considered as the promising solution to replace conventional lithium-ion batteries due to satisfactory energy density.In recent times,the LSBs field has been found to face some difficulties in exploring practical applications in which cycling stability and cycle life are awful owing to the shuttling effect of lithium polysulfides(LiPSs)and low sulfur utilization.In this work,by synthesizing Co_(3)Se_(4) nanoparticles onto N-doped carbon(NC)polyhedra interconnected with carbon nanotubes(CNTs),NC@Co_(3)Se_(4)/CNTs is proposed as a multifunctional sulfur carrier.The Co_(3)Se_(4) nanoparticles fleetly catalyze the conversion of LiPSs and availably immobilize LiPSs.Meanwhile,the NC polyhedral skeleton enhances the electronic conductivity of active sulfur,while the CNTs facilitate Li+diffusion and supply a mass of conductive channels.Density-functional theory(DFT)calculations demonstrate the relevant mechanisms.That is to say,the NC@Co_(3)Se_(4)/CNTs benefit from the synergistic effect of Co_(3)Se_(4) nanoparticles(highly catalytic ability and strong adsorbability for LiPSs)and the special carbonaceous structure,rapidly converting LiPSs and inhibiting the shuttle of LiPSs.Therefore,lithium-sulfur battery assembled with S/NC@Co_(3)Se_(4)/CNTs cathode as well as nitrogen and sulfur co-doped carbon-coated polypropylene(N,S-C/PP)separator possesses a high initial discharge capacity of 1413 mAh·g-1 at 0.12C and persistently circulates for 1000 cycles at 1C with a capacity attenuation rate per cycle of 0.034%.This work provides a realistic idea for the use of transition metal selenide in the field of high-performance LSBs.
基金funded by the"14th Five-Year Plan"Civil Aerospace Pre-research Project of China(Grant No.D010301).
文摘Reusable and flexible capturing of space debris is highly required in future aerospace technologies.A tendon-actuated flexible robotic arm is therefore proposed for capturing floating targets in this paper.Firstly,an accurate dynamic model of the flexible robotic arm is established by using the absolute nodal coordinate formulation(ANCF)in the framework of the arbitrary Lagrangian-Eulerian(ALE)description and the natural coordinate formulation(NCF).The contact and self-contact dynamics of the flexible robotic arm when bending and grasping an object are considered via a fast contact detection approach.Then,the dynamic simulations of the flexible robotic arm for capturing floating targets are carried out to study the influence of the position,size,and mass of the target object on the grasping performance.Finally,a principle prototype of the tendon-actuated flexible robotic arm is manufactured to validate the dynamic model.The corresponding grasping experiments for objects of various shapes are also conducted to illustrate the excellent performance of the flexible robotic arm.
文摘随着清洁可再生能源的不断发展,利用洋流能为水下微型无线传感器提供电能已成为研究热点。水下涡激振动能量俘获系统是一种在浅海低流速条件下利用涡激振动效应俘获洋流能的发电装置。本文将非线性恢复力、单向轴承及齿轮齿条机构与振动钝体结合,提出一种新型基于洋流能的涡激振动能量俘获系统。采用Van der Pol方程描述流体和钝体间的耦合效应,建立系统流-固-电耦合动力学方程。对系统进行稳定性分析,得到系统在单稳、双稳及三稳态情况下的参数数值范围,将3种稳态下系统的振幅比进行对比,发现系统处于三稳态时具有较强的发电优势。借助数值仿真,通过钝体振动的时域图、相图、分岔图及庞加莱截面详细研究流体参数(水流流速)和结构参数(质量比和阻尼比)对系统位移响应的影响,并分析单向轴承对传动轴转速的影响。分析质量比和阻尼比对发电功率的影响。结果表明,三稳态系统拥有非常丰富的非线性动力学行为,出现混沌运动、多周期运动及准周期运动,阻尼比的变化主要影响发电功率的峰值,而质量比的变化主要影响涡激振动的共振区间范围。
基金Program for Innovative Research Team in University(IRT520)CAST of China (20090703)
文摘When the space robot captures a floating target, contact impact occurs inevitably and frequently between the manipulator hand and the target, which seriously impacts the position and attitude of the robot and grasping security. ＂Dynamic grasping area＂ is introduced to describe the collision process of manipulator grasping target, and grasping area control equation is established. By analyzing the impact of grasping control parameters, base and target mass on the grasping process and combining the life experience, it is found that if the product of speed control parameter and dB adjustment parameter is close to but smaller than the minimum grasping speed, collision impact in the grasping process could be reduced greatly, and then an ideal grasping strategy is proposed. Simulation results indicate that during the same period, the strategy grasping is superior to the accelerating grasping, in that the amplitude of impact force is reduced to 20%, and the attitude control torque is reduced to 15%, and the impact on the robot is eliminated significantly. The results would have important academic value and engineering significance.
文摘【目的】考虑系统清洁低碳的前提下,综合能源系统中能源产品定价与市场用户的经济利益和能源运营商的盈利能力密切相关。为此,对含电转气-碳捕集电厂(power to gas-carbon capture power plant,P2G-CCPP)的综合能源系统(integrated energy system,IES)进行㶲经济分析。【方法】从㶲视角出发,兼顾能量的量与质,针对不同能流进行㶲值计算,建立㶲流计算子模型。将系统低碳经济性引入㶲经济分析中,将碳排放权交易成本、碳捕集能耗成本及碳封存成本纳入非能量成本中,建立㶲经济成本分摊子模型。相较于传统定价方法,考虑了碳成本及能量品位差异对系统冷热电单位㶲成本的影响,体现优质优价原则。【结果】仿真算例表明引入P2G-CCPP联动系统能够提高系统低碳减排能力,实现成本合理分摊。【结论】含P2G-CCPP机组的综合能源系统能够有效削减系统总成本及冷热电单位成本,增强了碳利用和燃气生产消费的节能减排途径,具有显著的经济及社会效益。
