The Experts below are selected from a list of 4650 Experts worldwide ranked by ideXlab platform
Guangren Duan - One of the best experts on this subject based on the ideXlab platform.
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optimal Soft Landing control for moon lander
Automatica, 2008Co-Authors: Guangren DuanAbstract:This paper considers the Soft Landing problem of a moon lander. The main purpose is to design the optimal control law to ensure the Soft Landing of the lander with the least fuel consumption. It is formulated as a constrained optimal control problem, where specific requirements of this Soft Landing problem are all incorporated in the problem formulation. Then, by utilizing the specific features of the problem, this optimal Soft Landing problem is transformed into an equivalent standard optimal control problem subject to continuous state inequality constraints. A computational method is developed, based on the control parameterization in conjunction with a time scaling transform and the constraint transcription method, to design the optimal controller for this new constrained optimal control problem. Numerical results are presented for illustration.
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ROBIO - Study on the optimal fuel consumption of the singularity condition for lunar Soft Landing
2007 IEEE International Conference on Robotics and Biomimetics (ROBIO), 2007Co-Authors: Yongzheng Shan, Guangren DuanAbstract:To achieve the minimal fuel consumption, the Pontryagin maximum principle is utilized to generate an optimal guidance law for the whole process of the lunar probe's Soft Landing which starts off from the perilune. It is shown that the singularity condition for the optimal lunar Soft Landing process doesn't influence the fuel consumption.
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Study on the optimal fuel consumption of the singularity condition for lunar Soft Landing
2007 IEEE International Conference on Robotics and Biomimetics (ROBIO), 2007Co-Authors: Yongzheng Shan, Guangren DuanAbstract:To achieve the minimal fuel consumption, the Pontryagin maximum principle is utilized to generate an optimal guidance law for the whole process of the lunar probe's Soft Landing which starts off from the perilune. It is shown that the singularity condition for the optimal lunar Soft Landing process doesn't influence the fuel consumption.
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Design of Optimal Orbit and Constant Force for Soft-Landing of Lunar Lander
2006 Chinese Control Conference, 2006Co-Authors: Guangren DuanAbstract:This paper deals with the Soft Landing of lunar lander. A parametric piecewise constant controller is developed, which arbitrarily approaches the optimal continuous controller and has the parameters whose number is equal to the rank of the system. This controller transforms the optimal control to the parameter optimization which is easily solved by the standard mathematic programming. The Soft Landing problem is treated by using this controller. Optimal parameters are derived by the genetic algorithm. At last, the simulation results illustrate the feasibility and advantage of our approach.
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Study on the Singularity State for Optimal Lunar Soft Landing Process
2006 Chinese Control Conference, 2006Co-Authors: Yongzheng Shan, Guangren DuanAbstract:To achieve the minimal fuel consumption, the Pontryagin maximum principle is utilized to generate an optimal guidance law for the whole process of the lunar probe's Soft Landing which starts off from the perilune. It is shown that the singularity condition can not hold along an optimal trajectory on any closed time interval.
Dayi Wang - One of the best experts on this subject based on the ideXlab platform.
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gnc system scheme for lunar Soft Landing spacecraft
Advances in Space Research, 2008Co-Authors: Dayi Wang, Xiangyu Huang, Yifeng GuanAbstract:Abstract A pinpoint autonomous GNC system scheme for lunar Soft Landing is proposed. First, the descriptions of the mission outline for lunar Soft Landing are provided. Second, the GNC system design of the spacecraft is proposed. The baseline is a 3-axis stabilized system during all the phases of the mission. Orbit maneuvers are achieved by an assembled constant thrust or a throttleable main engine. The attitude control actuators are thrusters. The attitude and orbit determination is performed by sun sensors, star sensors, Inertial Measurement Unit (IMU), altimeter, velocimeter and lunar imaging sensors. Third, some proposed autonomous navigation and guidance methods including hazard detection and avoidance for lunar Soft Landing are analyzed. Finally, we draw some conclusions.
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ROBIO - Autonomous navigation and guidance for pinpoint lunar Soft Landing
2007 IEEE International Conference on Robotics and Biomimetics (ROBIO), 2007Co-Authors: Xiangyu Huang, Dayi WangAbstract:An autonomous navigation and guidance system scheme for pinpoint lunar Soft Landing is studied in this paper. First, the descriptions of outline of lunar Soft Landing process are provided. Second, a GNC system scheme for lunar Soft Landing spacecraft is described. Third, the autonomous navigation based on measurement-updated IMU for lunar Soft Landing is presented. Fourth, the autonomous explicit guidance for lunar Soft Landing is provided. Finally, the presented navigation and guidance method are validated by using the simulation and some conclusions are drawn.
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Autonomous navigation and guidance for pinpoint lunar Soft Landing
2007 IEEE International Conference on Robotics and Biomimetics (ROBIO), 2007Co-Authors: Xiangyu Huang, Dayi WangAbstract:An autonomous navigation and guidance system scheme for pinpoint lunar Soft Landing is studied in this paper. First, the descriptions of outline of lunar Soft Landing process are provided. Second, a GNC system scheme for lunar Soft Landing spacecraft is described. Third, the autonomous navigation based on measurement-updated IMU for lunar Soft Landing is presented. Fourth, the autonomous explicit guidance for lunar Soft Landing is provided. Finally, the presented navigation and guidance method are validated by using the simulation and some conclusions are drawn.
S. Haghighat - One of the best experts on this subject based on the ideXlab platform.
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Robust dual control MPC with application to Soft-Landing control
2015 American Control Conference (ACC), 2015Co-Authors: Y. Cheng, S. Haghighat, S. Di CairanoAbstract:Dual control frameworks for systems subject to uncertainties aim at simultaneously learning the unknown parameters while controlling the system dynamics. We propose a robust dual model predictive control algorithm for systems with bounded uncertainty with application to Soft Landing control. The algorithm exploits a robust control invariant set to guarantee constraint enforcement in spite of the uncertainty, and a constrained estimation algorithm to guarantee admissible parameter estimates. The impact of the control input on parameter learning is accounted for by including in the cost function a reference input, which is designed online to provide persistent excitation. The reference input design problem is non-convex, and here is solved by a sequence of relaxed convex problems. The results of the proposed method in a Soft-Landing control application in transportation systems are shown.
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Soft-Landing control by control invariance and receding horizon control
2014 American Control Conference, 2014Co-Authors: Stefano Di Cairano, A. Ulusoy, S. HaghighatAbstract:We propose a design for Soft Landing control based on control invariant sets and receding horizon control. Soft Landing control, which is of interest in several applications in aerospace, transportation systems, and factory automation, aims at achieving precise positioning of a moving object to a target position, while ensuring that the maximum velocity decreases as the target is approached. The resulting Soft contact avoids damages and wear. In this paper, we formulate appropriate constraints and recast Soft Landing control as the generation of an admissible trajectory of the constrained system. Then, we compute a control invariant set and design a receding horizon control law that forces the state to remain in such set. Thus, the trajectories generated by the controller achieve Soft Landing, regardless of the controller cost function and horizon, also when the dynamics are uncertain. We demonstrate our approach by a case study in transportation systems.
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ACC - Soft-Landing control by control invariance and receding horizon control
2014 American Control Conference, 2014Co-Authors: Stefano Di Cairano, A. Ulusoy, S. HaghighatAbstract:We propose a design for Soft Landing control based on control invariant sets and receding horizon control. Soft Landing control, which is of interest in several applications in aerospace, transportation systems, and factory automation, aims at achieving precise positioning of a moving object to a target position, while ensuring that the maximum velocity decreases as the target is approached. The resulting Soft contact avoids damages and wear. In this paper, we formulate appropriate constraints and recast Soft Landing control as the generation of an admissible trajectory of the constrained system. Then, we compute a control invariant set and design a receding horizon control law that forces the state to remain in such set. Thus, the trajectories generated by the controller achieve Soft Landing, regardless of the controller cost function and horizon, also when the dynamics are uncertain. We demonstrate our approach by a case study in transportation systems.
Xiangyu Huang - One of the best experts on this subject based on the ideXlab platform.
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autonomous hazard avoidance control for chang e 3 Soft Landing
Scientia Sinica Technologica, 2014Co-Authors: Honghua Zhang, Xiangyu Huang, Yifeng Guan, Jun Liang, Yu Zhao, Li Wang, Ming Cheng, L I Ji, Pengji Wang, Li YuanAbstract:ChangE-3 is the first mission of Chinese Soft Landing on celestial body outside Earth. ChangE-3 firstly implements the autonomous hazard avoidance of Soft Landing using the onboard measured image data. For the feature of autonomous hazard avoidance mission, ChangE-3 firstly presents the relay hazard avoidance control method including the large hazard avoidance of gray-scale-safe & attitude maneuver and the fine hazard avoidance of altitude-safe & position-attitude maneuver. The real flight results of ChangE-3 show that in the powered descent process the safe Landing site is acquired, the precise hazard avoidance maneuver is achieved perfectly, and the safety of touch point for Soft Landing is insured. The autonomous hazard avoidance control and onboard flight results for ChangE-3 are described.
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gnc system scheme for lunar Soft Landing spacecraft
Advances in Space Research, 2008Co-Authors: Dayi Wang, Xiangyu Huang, Yifeng GuanAbstract:Abstract A pinpoint autonomous GNC system scheme for lunar Soft Landing is proposed. First, the descriptions of the mission outline for lunar Soft Landing are provided. Second, the GNC system design of the spacecraft is proposed. The baseline is a 3-axis stabilized system during all the phases of the mission. Orbit maneuvers are achieved by an assembled constant thrust or a throttleable main engine. The attitude control actuators are thrusters. The attitude and orbit determination is performed by sun sensors, star sensors, Inertial Measurement Unit (IMU), altimeter, velocimeter and lunar imaging sensors. Third, some proposed autonomous navigation and guidance methods including hazard detection and avoidance for lunar Soft Landing are analyzed. Finally, we draw some conclusions.
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ROBIO - Autonomous navigation and guidance for pinpoint lunar Soft Landing
2007 IEEE International Conference on Robotics and Biomimetics (ROBIO), 2007Co-Authors: Xiangyu Huang, Dayi WangAbstract:An autonomous navigation and guidance system scheme for pinpoint lunar Soft Landing is studied in this paper. First, the descriptions of outline of lunar Soft Landing process are provided. Second, a GNC system scheme for lunar Soft Landing spacecraft is described. Third, the autonomous navigation based on measurement-updated IMU for lunar Soft Landing is presented. Fourth, the autonomous explicit guidance for lunar Soft Landing is provided. Finally, the presented navigation and guidance method are validated by using the simulation and some conclusions are drawn.
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Autonomous navigation and guidance for pinpoint lunar Soft Landing
2007 IEEE International Conference on Robotics and Biomimetics (ROBIO), 2007Co-Authors: Xiangyu Huang, Dayi WangAbstract:An autonomous navigation and guidance system scheme for pinpoint lunar Soft Landing is studied in this paper. First, the descriptions of outline of lunar Soft Landing process are provided. Second, a GNC system scheme for lunar Soft Landing spacecraft is described. Third, the autonomous navigation based on measurement-updated IMU for lunar Soft Landing is presented. Fourth, the autonomous explicit guidance for lunar Soft Landing is provided. Finally, the presented navigation and guidance method are validated by using the simulation and some conclusions are drawn.
Graham R Cooks - One of the best experts on this subject based on the ideXlab platform.
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in situ raman spectroscopy of surfaces modified by ion Soft Landing
Analyst, 2012Co-Authors: Jobin Cyriac, Michael Wleklinski, Guangtao Li, Graham R CooksAbstract:The design and characterization of a system for in situ Raman analysis of surfaces prepared by ion Soft Landing (SL) is described. The performance of the new high vacuum compatible, low cost, surface analysis capability is demonstrated with surface enhanced Raman spectroscopy (SERS) of surfaces prepared by Soft Landing of ions of crystal violet, Rhodamine 6G, methyl orange and copper phthalocyanine. Complementary in situ mass spectrometric information is recorded for the same surfaces using a previously implemented secondary ion mass spectrometer (SIMS). Imaging of the modified surfaces is achieved using 2D Raman imaging as demonstrated for the case of Rhodamine 6G Soft Landing. The combination of the powerful molecular characterization tools of SERS and SIMS in a single instrument fitted with in-vacuum sample transport capabilities, facilitates in situ analysis of surfaces prepared by ion SL. In particular, information is provided on the charge state of the Soft landed species. In the case of crystal violet the SERS data suggest that the positively charged ions being landed retain their charge state on the surface under vacuum. By contrast, in the case of methyl orange which is landed as an anion, the SERS spectra suggest that the SL species has been neutralized.
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ion Soft Landing using a rectilinear ion trap mass spectrometer
Analytical Chemistry, 2008Co-Authors: Wenping Peng, Michael P Goodwin, Michael Volný, Zheng Ouyang, Graham R CooksAbstract:A new ion Soft Landing instrument has been built for the controlled deposition of mass selected polyatomic ions. The instrument has been operated with an electrospray ionization source; its major components are an electrodynamic ion funnel to reduce ion loss, a 90-degree bent square quadrupole that prevents deposition of fast neutral molecules onto the Landing surface, and a novel rectilinear ion trap (RIT) mass analyzer. The ion trap is elongated (inner dimensions: 8 mm × 10 mm × 10 cm). Three methods of mass analysis have been implemented. (i) A conventional mass-selective instability scan with radial resonance ejection can provide a complete mass spectrum. (ii) The RIT can also be operated as a continuous rf/dc mass filter for isolation and subsequent Soft Landing of ions of the desired m/z value. (iii) The 90-degree bent square quadrupole can also be used as a continuous rf/dc mass filter. The mass resolution (50% definition) of the RIT in the trapping mode (radial ion ejection) is ∼550. Ions from var...
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ion surface reactions and ion Soft Landing
Physical Chemistry Chemical Physics, 2005Co-Authors: Bogdan Gologan, Jason R Green, Jormarie Alvarez, Julia Laskin, Graham R CooksAbstract:Ion/surface collision phenomena in the hyperthermal collision energy regime (1–100 eV) are reviewed, with emphasis on chemical processes associated with the impact of small organic and biological ions at functionalized self-assembled monolayer surfaces. Inelastic collisions can lead to excitation of the projectile ion and can result in fragmentation, a process known as surface-induced dissociation which is useful in chemical analysis using tandem mass spectrometry. Changes in charge can accompany ion/surface collisions and those associated with a change in polarity (positive to negative ions or vice versa) are an attractive method for ion structural characterization and isomer differentiation. The surface-induced charge inversion of nitrobenzene and other substituted aromatics is discussed. Reactive collisions occurring between gaseous ions and surfaces depend on the chemical nature of the collision partners. These reactions can be used for selected chemical modifications of surfaces as well as for surface analysis. Particular emphasis is given here to ion Soft-Landing, another type of ion/surface interaction, in which the projectile ion is landed intact at the surface, either as the corresponding neutral molecule or, interestingly but less commonly, in the form of the ion itself. The ion Soft-Landing experiment allows for preparative mass spectrometry; for example the preparation of pure biological compounds by using the mass spectrometer as a separation device. After separation, the mass-selected ions are collected by Soft-Landing, at different spatial points in an array. If the experiment is performed using a suitable liquid medium, in the case of some proteins at least, biological activity is retained.
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ion Soft Landing into liquids protein identification separation and purification with retention of biological activity
Journal of the American Society for Mass Spectrometry, 2004Co-Authors: Bogdan Gologan, Jormarie Alvarez, Zheng Ouyang, Zoltan Takats, Justin M Wiseman, Nari Talaty, Graham R CooksAbstract:Protein ions, after mass spectrometric separation, can be Soft-landed into liquid surfaces with preservation of their native structures. Retention of biological activity is strongly favored in glycerol-based surfaces but not in self-assembled monolayer solid surfaces. Soft-Landing efficiency for multiply-charged hexokinase ions was found to be some four times higher for a glycerol/fructose liquid surface than for a fluorinated self-assembled monolayer surface. Soft-Landing into liquid surfaces is also shown to allow (1) protein purification, (2) on-surface identification of the Soft-landed material using MALDI, and (3) protein identification by in-surface tryptic digestion. Pure lysozyme was successfully isolated from different mixtures including an oxidized, partially decomposed batch of the protein and a partial tryptic digest. Liquid glycerol/carbohydrate mixtures could be used directly to record MALDI spectra on the Soft-landed compounds provided they were fortified in advance with traditional MALDI matrices such as p-nitroaniline and α-cyano-4-hydroxycinnamic acid. Various proteins were Soft-landed and detected on-target using these types of liquid surface. Soft-Landing of multiply-charged lysozyme ions onto fluorinated self-assembled monolayer surfaces was found to occur with a limited amount of neutralization, and trapped multiply-charged ions could be desorbed from the surface by laser desorption. Initial data is shown for a new approach to protein identification that combines top-down and bottom-up approaches by utilizing protein ion Soft-Landing from a protein mixture, followed by tryptic digestion of the landed material and detection of characteristic tryptic fragments by MALDI.
