The Experts below are selected from a list of 15864 Experts worldwide ranked by ideXlab platform
Rui Zhang - One of the best experts on this subject based on the ideXlab platform.
-
uav enabled wireless power Transfer Trajectory design and energy optimization
2018Co-Authors: Jie Xu, Yong Zeng, Rui ZhangAbstract:This paper studies a new unmanned aerial vehicle (UAV)-enabled wireless power Transfer system, where a UAV-mounted mobile energy transmitter is dispatched to deliver wireless energy to a set of energy receivers (ERs) at known locations on the ground. We investigate how the UAV should optimally exploit its mobility via Trajectory design to maximize the amount of energy Transferred to all ERs during a finite charging period. First, we consider the maximization of the sum energy received by all ERs by optimizing the UAV’s Trajectory subject to its maximum speed constraint. Although this problem is non-convex, we obtain its optimal solution, which shows that the UAV should hover at one single fixed location during the whole charging period. However, the sum-energy maximization incurs a “near-far” fairness issue, where the received energy by the ERs varies significantly with their distances to the UAV’s optimal hovering location. To overcome this issue, we consider a different problem to maximize the minimum received energy among all ERs, which, however, is more challenging to solve than the sum-energy maximization. To tackle this problem, we first consider an ideal case by ignoring the UAV’s maximum speed constraint, and show that the relaxed problem can be optimally solved via the Lagrange dual method. The obtained Trajectory solution implies that the UAV should hover over a set of fixed locations with optimal hovering time allocations among them. Then, for the general case with the UAV’s maximum speed constraint considered, we propose a new successive hover-and-fly Trajectory motivated by the optimal Trajectory in the ideal case and obtain efficient Trajectory designs by applying the successive convex programing optimization technique. Finally, numerical results are provided to evaluate the performance of the proposed designs under different setups, as compared with benchmark schemes.
-
uav enabled multiuser wireless power Transfer Trajectory design and energy optimization
2017Co-Authors: Yong Zeng, Rui ZhangAbstract:This paper investigates an unmanned aerial vehicle (UAV)-enabled multiuser wireless power Transfer (WPT) system, where a UAV-mounted energy transmitter (ET) is dispatched to broadcast wireless energy to charge multiple energy receivers (ERs) on the ground. To ensure efficient and fair WPT, we maximize the minimum of the energy harvested by all ERs during a given charging period, by optimizing the UAV's Trajectory subject to its maximum speed constraints. Such a min-energy maximization problem, however, is non-convex, and thus is challenging to be directly solved. To tackle this problem, we first consider an ideal case by ignoring the UAV's maximum speed constraint, and show that the relaxed problem can be optimally solved via the Lagrange dual method. The obtained Trajectory solution implies that the UAV should hover over a set of fixed locations with optimal allocation of the hovering time among them. Then, for the general case with the UAV's maximum speed constraint considered, we propose a new successive hover-and-fly Trajectory motivated by the optimal Trajectory in the ideal case, and obtain efficient Trajectory designs by applying the successive convex programing (SCP) optimization technique. Numerical results show that our proposed Trajectory designs significantly improve the min-energy Transferred to all ERs, as compared to other benchmark schemes.
-
uav enabled wireless power Transfer Trajectory design and energy optimization
2017Co-Authors: Jie Xu, Yong Zeng, Rui ZhangAbstract:This paper studies a new unmanned aerial vehicle (UAV)-enabled wireless power Transfer (WPT) system, where a UAV-mounted mobile energy transmitter (ET) is dispatched to deliver wireless energy to a set of on-ground energy receivers (ERs). We investigate how the UAV should optimally exploit its mobility via Trajectory design to maximize the energy Transferred to all ERs during a finite period. First, we consider the maximization of the sum energy received by all ERs by optimizing the UAV's Trajectory subject to its maximum speed constraint. We obtain its optimal solution, which shows that the UAV should hover at one single fixed location during the whole period. However, the sum-energy maximization incurs a "near-far" fairness issue. To overcome this issue, we consider a different problem to maximize the minimum received energy among all ERs. We first consider an ideal case by ignoring the UAV's maximum speed constraint, and show that the relaxed problem can be optimally solved via the Lagrange dual method. Then, for the general case with the UAV's maximum speed constraint considered, we propose a new successive hover-and-fly Trajectory motivated by the optimal Trajectory in the ideal case, and obtain efficient Trajectory designs by applying the successive convex programing (SCP).
-
uav enabled wireless power Transfer Trajectory design and energy region characterization
2017Co-Authors: Jie Xu, Yong Zeng, Rui ZhangAbstract:This paper studies a new unmanned aerial vehicle (UAV)-enabled wireless power Transfer (WPT) system, where a UAV-mounted energy transmitter (ET) broadcasts wireless energy to charge distributed energy receivers (ERs) on the ground. In particular, we consider a basic two-user scenario, and investigate how the UAV can optimally exploit its mobility to maximize the amount of energy Transferred to the two ERs during a given charging period. We characterize the achievable energy region of the two ERs, by optimizing the UAV's Trajectory subject to a maximum speed constraint. We show that when the distance between the two ERs is smaller than a certain threshold, the boundary of the energy region is achieved when the UAV hovers above a fixed location between them for all time; while when their distance is larger than the threshold, to achieve the boundary of the energy region, the UAV in general needs to hover and fly between two different locations above the line connecting them. Numerical results show that the optimized UAV Trajectory can significantly improve the WPT efficiency and fairness of the two ERs, especially when the UAV's maximum speed is large and/or the charging duration is long.
-
uav enabled wireless power Transfer Trajectory design and energy region characterization
2017Co-Authors: Jie Xu, Yong Zeng, Rui ZhangAbstract:This paper studies a new unmanned aerial vehicle (UAV)- enabled wireless power Transfer (WPT) system, where a UAV-mounted energy transmitter (ET) broadcasts wireless energy to charge distributed energy receivers (ERs) on the ground. In particular, we consider a basic two-user scenario, and investigate how the UAV can optimally exploit its mobility via Trajectory design to maximize the amount of energy Transferred to the two ERs during a finite charging period. We characterize the achievable energy region of the two ERs, by optimizing the UAV's Trajectory subject to a maximum speed constraint. We show that when the distance between the two ERs is smaller than a certain threshold, the Pareto boundary of the energy region is achieved when the UAV hovers above a fixed location between them during the whole charging period; while when their distance is larger than the threshold, to achieve the boundary of the energy region, the UAV in general needs to hover and fly between two different locations above the line connecting them. Numerical results show that the optimized UAV Trajectory can significantly improve the WPT efficiency and fairness of the two ERs, especially when the UAV's maximum speed is large and/or the charging duration is long.
David Folta - One of the best experts on this subject based on the ideXlab platform.
-
the lunar icecube mission design construction of feasible Transfer trajectories with a constrained departure
2016Co-Authors: David Folta, Natasha Bosanac, Andrew D Cox, Kathleen C. HowellAbstract:Lunar IceCube, a 6U CubeSat, will prospect for water and other volatiles from a low-periapsis, highly inclined elliptical lunar orbit. Injected from Exploration Mission-1, a lunar gravity assisted multi-body Transfer Trajectory will capture into a lunar science orbit. The constrained departure asymptote and value of trans-lunar energy limit Transfer Trajectory types that re-encounter the Moon with the necessary energy and flight duration. Purdue University and Goddard Space Flight Center's Adaptive Trajectory Design tool and dynamical system research is applied to uncover cislunar spatial regions permitting viable Transfer arcs. Numerically integrated Transfer designs applying low-thrust and a design framework are described.
-
Lunar Cube Transfer Trajectory Options
2015Co-Authors: David Folta, D. J. Dichmann, Pamela Clark, Amanda F. Haapala, Kathleen C. HowellAbstract:Contingent upon the modification of an initial condition of the injected or deployed orbit. Additionally, these designs can be restricted by the selection of the Cubesat subsystem design such as propulsion or communication. Nonetheless, many Trajectory options can be designed with have a wide range of Transfer durations, fuel requirements, and final destinations. Our investigation of potential trajectories highlights several design options including deployment into low Earth orbit (LEO), geostationary Transfer orbits (GTO), and higher energy direct lunar Transfer orbits. In addition to direct Transfer options from these initial orbits, we also investigate the use of longer duration Earth-Moon dynamical systems. For missions with an intended lunar orbit, much of the design process is spent optimizing a ballistic capture while other science locations such as Sun-Earth libration or heliocentric orbits may simply require a reduced Delta-V imparted at a convenient location along the Trajectory. In this article we examine several design options that meet the above limited deployment and subsystem drivers. We study ways that both impulsive and low-thrust Solar Electric Propulsion (SEP) engines can be used to place the Cubesat first into a highly eccentric Earth orbit, enter the Moon's Sphere of Influence, and finally achieve a highly eccentric lunar orbit. We show that such low-thrust Transfers are feasible with a realistic micro-thruster model, assuming that the Cubesat can generate sufficient power for the SEP. Two examples are shown here: (1) A Cubestat injected by Exploration Mission 1 (EM-1) then employing low thrust; and (2) a CubSat deployed in a GTO, then employing impulsive maneuvers. For the EM-1 injected initial design, we increase the EM-1 targeted lunar flyby distance to reduce the energy of the lunar flyby to match that of a typical lMoon system heteroclinic manifold. Figure 1 presents an option that encompasses the similar dynamics as that of the ARTEMIS mission design. Low-thrust maneuvers are used along the manifold Trajectory to raise perigee to that of a lunar orbit, adjust the timing with respect to the Moon, rotate the line of apsides, and target a ballistic lunar encounter. In this design a second flyby decreases the orbital energy with respect to the Moon, so that C3 -0.1 km2s2. Another design, shown in Figure 2 emanates from a GTO then uses impulsive maneuvers to phase onto a local Earth-Moon manifold, which then Transfers the CubeSat to a lunar encounter.
-
lunar cube Transfer Trajectory options
2015Co-Authors: David Folta, D. J. Dichmann, Pamela Clark, Amanda F. Haapala, Kathleen C. HowellAbstract:Numerous Earth-Moon Trajectory and lunar orbit options are available for Cubesat missions. Given the limited Cubesat injection infrastructure, Transfer trajectories are contingent upon the modification of an initial condition of the injected or deployed orbit. Additionally, these Transfers can be restricted by the selection or designs of Cubesat subsystems such as propulsion or communication. Nonetheless, many Trajectory options can b e considered which have a wide range of Transfer duration, fuel requirements, and final destinations. Our investigation of potential trajectories highlights several options including deployment from low Earth orbit (LEO) geostationary Transfer orbits (GTO) and higher energy direct lunar Transfer and the use of longer duration Earth-Moon dynamical systems. For missions with an intended lunar orbit, much of the design process is spent optimizing a ballistic capture while other science locations such as Sun-Earth libration or heliocentric orbits may simply require a reduced Delta-V imparted at a convenient location along the Trajectory.
-
Transfer Trajectory design for the mars atmosphere and volatile evolution maven mission
2013Co-Authors: David Folta, Stuart Demcak, Brian Young, Kevin BerryAbstract:The Mars Atmosphere and Volatile Evolution (MAVEN) mission will determine the history of the loss of volatiles from the Martian atmosphere from a highly inclined elliptical orbit. MAVEN will launch from Cape Canaveral Air Force Station on an Atlas-V 401 during an extended 36-day launch period opening November 18, 2013. The MAVEN Navigation and Mission Design team performed a Monte Carlo analysis of the Type-II Transfer to characterize; dispersions of the arrival B-Plane, Trajectory correction maneuvers (TCMs), and the probability of Mars impact. This paper presents detailed analysis of critical MOI event coverage, maneuver constraints, deltaV-99 budgets, and Planetary Protection requirements.
-
applications of multi body dynamical environments the artemis Transfer Trajectory design
2010Co-Authors: David Folta, Kathleen C. Howell, Mark Woodard, Chris Patterson, Wayne SchleiAbstract:The application of forces in multi-body dynamical environments to pennit the Transfer of spacecraft from Earth orbit to Sun-Earth weak stability regions and then return to the Earth-Moon libration (L1 and L2) orbits has been successfully accomplished for the first time. This demonstrated Transfer is a positive step in the realization of a design process that can be used to Transfer spacecraft with minimal Delta-V expenditures. Initialized using gravity assists to overcome fuel constraints; the ARTEMIS Trajectory design has successfully placed two spacecraft into EarthMoon libration orbits by means of these applications.
Kathleen C. Howell - One of the best experts on this subject based on the ideXlab platform.
-
the lunar icecube mission design construction of feasible Transfer trajectories with a constrained departure
2016Co-Authors: David Folta, Natasha Bosanac, Andrew D Cox, Kathleen C. HowellAbstract:Lunar IceCube, a 6U CubeSat, will prospect for water and other volatiles from a low-periapsis, highly inclined elliptical lunar orbit. Injected from Exploration Mission-1, a lunar gravity assisted multi-body Transfer Trajectory will capture into a lunar science orbit. The constrained departure asymptote and value of trans-lunar energy limit Transfer Trajectory types that re-encounter the Moon with the necessary energy and flight duration. Purdue University and Goddard Space Flight Center's Adaptive Trajectory Design tool and dynamical system research is applied to uncover cislunar spatial regions permitting viable Transfer arcs. Numerically integrated Transfer designs applying low-thrust and a design framework are described.
-
Lunar Cube Transfer Trajectory Options
2015Co-Authors: David Folta, D. J. Dichmann, Pamela Clark, Amanda F. Haapala, Kathleen C. HowellAbstract:Contingent upon the modification of an initial condition of the injected or deployed orbit. Additionally, these designs can be restricted by the selection of the Cubesat subsystem design such as propulsion or communication. Nonetheless, many Trajectory options can be designed with have a wide range of Transfer durations, fuel requirements, and final destinations. Our investigation of potential trajectories highlights several design options including deployment into low Earth orbit (LEO), geostationary Transfer orbits (GTO), and higher energy direct lunar Transfer orbits. In addition to direct Transfer options from these initial orbits, we also investigate the use of longer duration Earth-Moon dynamical systems. For missions with an intended lunar orbit, much of the design process is spent optimizing a ballistic capture while other science locations such as Sun-Earth libration or heliocentric orbits may simply require a reduced Delta-V imparted at a convenient location along the Trajectory. In this article we examine several design options that meet the above limited deployment and subsystem drivers. We study ways that both impulsive and low-thrust Solar Electric Propulsion (SEP) engines can be used to place the Cubesat first into a highly eccentric Earth orbit, enter the Moon's Sphere of Influence, and finally achieve a highly eccentric lunar orbit. We show that such low-thrust Transfers are feasible with a realistic micro-thruster model, assuming that the Cubesat can generate sufficient power for the SEP. Two examples are shown here: (1) A Cubestat injected by Exploration Mission 1 (EM-1) then employing low thrust; and (2) a CubSat deployed in a GTO, then employing impulsive maneuvers. For the EM-1 injected initial design, we increase the EM-1 targeted lunar flyby distance to reduce the energy of the lunar flyby to match that of a typical lMoon system heteroclinic manifold. Figure 1 presents an option that encompasses the similar dynamics as that of the ARTEMIS mission design. Low-thrust maneuvers are used along the manifold Trajectory to raise perigee to that of a lunar orbit, adjust the timing with respect to the Moon, rotate the line of apsides, and target a ballistic lunar encounter. In this design a second flyby decreases the orbital energy with respect to the Moon, so that C3 -0.1 km2s2. Another design, shown in Figure 2 emanates from a GTO then uses impulsive maneuvers to phase onto a local Earth-Moon manifold, which then Transfers the CubeSat to a lunar encounter.
-
lunar cube Transfer Trajectory options
2015Co-Authors: David Folta, D. J. Dichmann, Pamela Clark, Amanda F. Haapala, Kathleen C. HowellAbstract:Numerous Earth-Moon Trajectory and lunar orbit options are available for Cubesat missions. Given the limited Cubesat injection infrastructure, Transfer trajectories are contingent upon the modification of an initial condition of the injected or deployed orbit. Additionally, these Transfers can be restricted by the selection or designs of Cubesat subsystems such as propulsion or communication. Nonetheless, many Trajectory options can b e considered which have a wide range of Transfer duration, fuel requirements, and final destinations. Our investigation of potential trajectories highlights several options including deployment from low Earth orbit (LEO) geostationary Transfer orbits (GTO) and higher energy direct lunar Transfer and the use of longer duration Earth-Moon dynamical systems. For missions with an intended lunar orbit, much of the design process is spent optimizing a ballistic capture while other science locations such as Sun-Earth libration or heliocentric orbits may simply require a reduced Delta-V imparted at a convenient location along the Trajectory.
-
applications of multi body dynamical environments the artemis Transfer Trajectory design
2010Co-Authors: David Folta, Kathleen C. Howell, Mark Woodard, Chris Patterson, Wayne SchleiAbstract:The application of forces in multi-body dynamical environments to pennit the Transfer of spacecraft from Earth orbit to Sun-Earth weak stability regions and then return to the Earth-Moon libration (L1 and L2) orbits has been successfully accomplished for the first time. This demonstrated Transfer is a positive step in the realization of a design process that can be used to Transfer spacecraft with minimal Delta-V expenditures. Initialized using gravity assists to overcome fuel constraints; the ARTEMIS Trajectory design has successfully placed two spacecraft into EarthMoon libration orbits by means of these applications.
-
optimization of insertion cost for Transfer trajectories to libration point orbits
1999Co-Authors: Kathleen C. Howell, Roby S WilsonAbstract:The objective of this work is the development of efficient techniques to optimize the cost associated with Transfer trajectories to libration point orbits in the Sun-Earth-Moon four body problem, that may include lunar gravity assists. Initially, dynamical systems theory is used to determine invariant manifolds associated with the desired libration point orbit. These manifolds are employed to produce an initial approximation to the Transfer Trajectory. Specific Trajectory requirements such as, Transfer injection constraints, inclusion of phasing loops, and targeting of a specified state on the manifold are then incorporated into the design of the Transfer Trajectory. A two level differential corrections process is used to produce a fully continuous Trajectory that satisfies the design constraints, and includes appropriate lunar and solar gravitational models. Based on this methodology, and using the manifold structure from dynamical systems theory, a technique is presented to optimize the cost associated with insertion onto a specified libration point orbit.
Eun-sup Sim - One of the best experts on this subject based on the ideXlab platform.
-
an earth moon Transfer Trajectory design and analysis considering spacecraft s visibility from daejeon ground station at tli and loi maneuvers
2010Co-Authors: Jin Woo, Young-joo Song, Sang-young Park, Hae-dong Kim, Eun-sup SimAbstract:E-mail: spark624@yonsei.ac.krTel: +82-2-2123-5687 Fax: +82-2-392-7680This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://cre-ativecommons.org/licenses/by-nc/3.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
-
An Earth-Moon Transfer Trajectory Design and Analysis Considering Spacecraft’s Visibility from Daejeon Ground Station at TLI and LOI Maneuvers
2010Co-Authors: Jin Woo, Young-joo Song, Sang-young Park, Hae-dong Kim, Eun-sup SimAbstract:The optimal Earth-Moon Transfer Trajectory considering spacecraft’s visibility from the Daejeon ground station visibility at both the trans lunar injection (TLI) and lunar orbit insertion (LOI) maneuvers is designed. Both the TLI and LOI maneuvers are assumed to be impulsive thrust. As the successful execution of the TLI and LOI maneuvers are crucial factors among the various lunar mission parameters, it is necessary to design an optimal lunar Transfer Trajectory which guarantees the visibility from a specified ground station while executing these maneuvers. The optimal Earth-Moon Transfer Trajectory is simulated by modifying the Korean Lunar Mission Design Software using Impulsive high Thrust Engine (KLMDS-ITE) which is developed in previous studies. Four different mission scenarios are established and simulated to analyze the effects of the spacecraft’s visibility considerations at the TLI and LOI maneuvers. As a result, it is found that the optimal Earth-Moon Transfer Trajectory, guaranteeing the spacecraft’s visibility from Daejeon ground station at both the TLI and LOI maneuvers, can be designed with slight changes in total amount of delta-Vs. About 1% difference is observed with the optimal Trajectory when none of the visibility condition is guaranteed, and about 0.04% with the visibility condition is only guaranteed at the time of TLI maneuver. The spacecraft’s mass which can delivered to the Moon, when both visibility conditions are secured is shown to be about 534 kg with assumptions of KSLV-2’s on-orbit mass about 2.6 tons. To minimize total mission delta-Vs, it is strongly recommended that visibility conditions at both the TLI and LOI maneuvers should be simultaneously implemented to the Trajectory optimization algorithm
-
The Earth-Moon Transfer Trajectory Design and Analysis using Intermediate Loop Orbits
2009Co-Authors: Young-joo Song, Jin Woo, Sang-young Park, Kyu-hong Choi, Eun-sup SimAbstract:Various Earth-Moon Transfer trajectories are designed and analyzed to prepare the future Korea's Lunar missions. Minimum fuel Trajectory solutions are obtained for the departure year of 2017, 2020, 2022, and every required mission phases are analyzed from Earth departure to the final lunar mission orbit. N-body equations of motion are formulated which include the gravitational effect of the Sun, Earth and Moon. In addition, accelerations due to geopotential harmonics, Lunar J2 and solar radiation pressures are considered. Impulsive high thrust is assumed as the main thrusting method of spacecraft with launcher capability of KSLV-2 which is planned to be developed. For the method of injecting a spacecraft into a trans Lunar Trajectory, both direct shooting from circular parking orbit and shooting from the multiple elliptical intermediate orbits are adapted, and their design results are compared and analyzed. In addition, spacecraft's visibility from Deajeon ground station are constrained to see how they affect the magnitude of TLI (Trans Lunar Injection) maneuver. The results presented in this paper includes launch opportunities, required optimal maneuver characteristics for each mission phase as well as the Trajectory characteristics and numerous related parameters. It is confirmed that the final mass of Korean lunar explorer strongly depends onto the initial parking orbit's altitude and launcher's capability, rather than mission start time
Biaosong Chen - One of the best experts on this subject based on the ideXlab platform.
-
multi objective Transfer to libration point orbits via the mixed low thrust and invariant manifold approach
2014Co-Authors: Haijun Peng, Biaosong ChenAbstract:The multi-objective optimization of Transfer trajectories from an orbit near Earth to a periodic libration-point orbit in the Sun–Earth system using the mixed low-thrust and invariant-manifold approach is investigated in this paper. A two-objective optimization model is proposed based on the mixed low-thrust and invariant-manifold approach. The circular restricted three-body model (CRTBP) is utilized to represent the motion of a spacecraft in the gravitational field of the Sun and Earth. The Transfer Trajectory is broken down into several segments; both low-thrust propulsion and stable manifolds are utilized based on the CRTBP in different segments. The fuel cost, which is generated only by the low-thrust Trajectory for Transferring the spacecraft from an orbit near Earth to a stable manifold, is minimized. The total flight time, which includes the time during which the spacecraft is controlled by the low-thrust Trajectory and the time during which the spacecraft is moving on the stable manifold, is also minimized. Using the nondominated sorting genetic algorithm for the resulting multi-objective optimization problem, highly promising Pareto-optimal solutions for the Transfer of the spacecraft are found. Via numerical simulations, it is shown that tradeoffs between time of flight and fuel cost can be quickly evaluated using this approach. Furthermore, for the same time of flight, Transfer trajectories based on the mixed-Transfer method can save a larger amount of fuel than the low-thrust method alone.