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Abort guidance During Lunar Powered Descent

JOURNAL OF guidance CONTROL AND DYNAMICS 2024年第3期47卷 394-406页

作者： Sandoval, Sergio A. Lu, Ping Hwang, John T. San Diego State Univ San Diego CA 92182 USA NASA Johnson Space Ctr Houston TX 77058 USA San Diego State Univ Dept Aerosp Engn San Diego CA 92182 USA Univ Calif San Diego Dept Mech & Aerosp Engn San Diego CA 92093 USA

During powered descent of a crewed lunar landing mission, the ability to abort and ascend into a clear pericynthion orbit is critical in case any contingency renders the landing infeasible or excessively risky. In such a case, it is incumbent upon the guidance system to determine autonomously a safe abort trajectory and the associated guidance command. To accomplish this task reliably, a novel two-phase abort guidance strategy is proposed in this paper where a pull-up maneuver redirects the velocity vector to help mitigate any ground collision risk and achieve an appropriate initial ascent condition, followed by a fuel-optimal ascent guidance algorithm to insert the spacecraft into a predefined safe orbit around the moon. Development of the pull-up guidance laws and a description of the fuel-optimal ascent guidance based on the indirect method of optimal control are presented. In-depth investigation is conducted to provide a full understanding of the validity of the abort solutions. The solutions and fuel efficiency of the proposed guidance strategy are independently verified by using a direct method of optimal control. Monte Carlo closed-loop simulations demonstrate the effectiveness and robustness of this method throughout the entire powered descent.

关键词： guidance, Navigation, and Control Systems Control Theory Solar System Moons Transversality Condition Space Missions guidance and navigational algorithms Energy Economics Propellant Flight Path Angle Powered Descent Initiation

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Urban Air Mobility guidance with Panel Method: Experimental Evaluation Under Wind Disturbances

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JOURNAL OF guidance CONTROL AND DYNAMICS 2024年第6期47卷 1080-1096页

作者： Bilgin, Zeynep Yavrucuk, Ilkay Bronz, Murat Tech Univ Munich Inst Rotorcraft & Vert Flight TUM Sch Engn & Design D-85748 Garching Germany Tech Univ Munich Inst Rotorcraft & Vert Flight TUM Sch Engn & Design D-85748 Garching Germany Univ Toulouse Ecole Natl Aviat Civile ENAC Lab Dynam SystENAC F-31400 Toulouse France

In this paper, a nature-inspired guidance algorithm based on the panel method is proposed. The panel method is a numerical tool borrowed from the aerodynamics domain to calculate the potential field of a fluid flow around arbitrarily shaped objects. The proposed algorithm has little computational load and generates guidance vectors in real time that can guide multiple vehicles through smooth and collision-free paths. Panel-method-based guidance is a promising candidate for air mobility applications in urban environments where multiple aerial vehicles are expected to operate simultaneously without colliding with architectural structures and other vehicles in the airspace. In this study, the effectiveness and feasibility of the proposed guidance method is evaluated through a test campaign conducted in Toulouse, France, using multiple quadrotors in a scaled urban environment. Furthermore, the robustness of the guidance method under wind disturbances is tested in both indoor and outdoor experiments. Experimental results suggest that the panel-method-based guidance algorithm is an effective and robust tool for real-time, collision-free guidance of multiple aerial vehicles in complex urban environments.

关键词： Urban Air Mobility guidance and navigational algorithms Quad Rotor Free Stream Velocity Airspace Fluid Flow Properties Real Time Path Planning Obstacle Avoidance

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Multi-Objective Robust Trajectory Design for Powered Descent and Landing

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JOURNAL OF SPACECRAFT AND ROCKETS 2024年第6期61卷 1496-1509页

作者： Calkins, Grace E. Putnam, Zachary R. Woffinden, David C. Univ Illinois Aerosp Engn Dept 104 S Wright St Urbana IL 61801 USA NASA Johnson Space Ctr GN&C Autonomous Syst Branch Houston TX 77508 USA

A robust trajectory optimization approach for guidance algorithm gain and target vector selection for powered descent and landing is developed. A genetic algorithm is used to determine optimized guidance algorithm parameters to minimize the impact of initial condition, environment, navigation, and vehicle property uncertainty on flight performance for a given sensor suite. Vehicle state uncertainties are computed efficiently using linear covariance analysis techniques. When implemented in the guidance algorithm, the optimized gains and target vectors shape a trajectory that has more favorable conditions for a given navigation sensor suite, resulting in improved flight performance. As a demonstration of this method, the optimized guidance parameters are found for a multiphase trajectory from powered descent initiation to touchdown for a robotic lunar landing mission. Single-objective optimization results demonstrate a reduction in uncertainty and an improvement in nominal performance. Multi-objective optimization results showing the tradeoff between terminal position uncertainty and total propellant usage are presented for multiple sensor suite compositions. Further, guidance parameters selected using the developed robust trajectory design approach may enable acceptable flight performance with fewer and/or lower-quality sensors. The resulting Pareto fronts present the optimal trade space early in the mission design process to enable informed decision-making.

关键词： Spacecraft Design Propellant Sensors Powered Descent Initiation guidance and navigational algorithms Genetic Algorithm Trajectory Optimization Space Missions Terrain Relative Navigation

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Rethinking Propellant-Optimal Powered Descent guidance

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JOURNAL OF guidance CONTROL AND DYNAMICS 2024年第10期47卷 2016-2028页

作者： Lu, Ping Davami, Christopher San Diego State Univ Dept Aerosp Engn San Diego CA 92182 USA

The propellant-optimal powered descent solution requires a bang-bang thrust magnitude profile that switches instantaneously between the upper and lower bounds of the engine thrust. Implementing a bang-bang thrust pattern for guidance can be challenging for the engine and may cause practical and operational difficulties. Motivated by the observation that excellent propellant performance does not appear to be predicated on necessarily having a bang-bang thrust structure, a new powered descent guidance method is proposed in this work. The foundation lies in a propellant-optimal problem in which the thrust magnitude is parameterized by a user-prescribed continuous function of time. In particular, constant and linear functions are considered. The solution determines the optimal thrust direction, time of flight, and design parameters defining the thrust function. An indirect-method-based guidance algorithm is developed to solve this problem rapidly and reliably. Substantial evidence is provided to demonstrate that the solutions proposed in this paper in general yield a propellant consumption very close to that of the optimal bang-bang solution. Given its comparable propellant performance, implementability, and robustness, this paper makes a strong case that the proposed propellant-optimal powered descent guidance approach is preferred to the long-standing bang-bang guidance approach.

关键词： guidance and navigational algorithms Powered Descent guidance Soft Landing guidance Spacecraft guidance Propellant-Optimized Autonomous Spacecraft Entry, Descent and Landing Optimal Control Problem

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Onboard Burn Targeting and guidance of NASA Human Flight Vehicles

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JOURNAL OF guidance CONTROL AND DYNAMICS 2024年第11期47卷 2241-2258页

作者： Goodman, John L. Odyssey Space Res LLC Houston TX 77058 USA

The mission requirements of crewed space vehicles flown by NASA drove the development of new techniques for burn targeting and guidance for ascent, rendezvous, lunar landing, and deorbit. The Saturn V Iterative guidance Mode used an approximately optimal steering law that could adjust the trajectory to compensate for performance issues while meeting trajectory constraints at propulsion-system cutoff. Hypersurface targeting provided constraints for the Saturn V Trans-Lunar Injection burn. E guidance, in quadratic- and linear-acceleration forms, provided closed-loop descent and ascent guidance for the Apollo Lunar Module. The Space Shuttle's Powered Explicit guidance algorithm was more flexible than Apollo-era guidance algorithms, and it had better convergence characteristics, enabling it to support challenging abort profiles. The Space Launch System has built on the heritage of the Space Shuttle's guidance algorithm. The Orion spacecraft's Two-Level Targeter enables onboard, autonomous targeting of an entire mission profile subject to three-body dynamics in cislunar space. Orion uses Shuttle-derived guidance as the basis for an orbit-guidance package with more capability than guidance algorithms of previous vehicles.

关键词： NASA guidance and navigational algorithms Exploration Upper Stage Clohessy Wiltshire Equation Sample Return Missions Satellite Launch Vehicle Crewed Spacecrafts Space Exploration and Technology Targeting algorithms Optimization Algorithm

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Time-Constrained Interception with Bounded Field of View and Input Using Barrier Lyapunov Approach

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JOURNAL OF guidance CONTROL AND DYNAMICS 2024年第2期47卷 384-393页

作者： Singh, Swati Kumar, Shashi Ranjan Mukherjee, Dwaipayan Indian Inst Technol Intelligent Syst & Control Lab Dept Aerosp Engn Mumbai 400076 India Indian Inst Technol Dept Elect Engn Mumbai 400076 India

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Convex-Optimization-Based Model Predictive Control for Space Debris Removal Mission guidance

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JOURNAL OF guidance CONTROL AND DYNAMICS 2024年第9期47卷 1885-1904页

作者： Wijayatunga, Minduli Charithma Armellin, Roberto Holt, Harry Pirovano, Laura Bombardelli, Claudio Univ Auckland Auckland Space Inst Mech Engn Dept 34 Princes St Auckland 1010 New Zealand Tech Univ Madrid Sch Aeronaut & Space Engn Space Dynam Grp Madrid 28040 Spain

A convex-optimization-based model predictive control (MPC) algorithm for the guidance of active debris removal missions is proposed in this work. A high-accuracy reference for the convex optimization is obtained through a split-Edelbaum approach that takes the effects of J2, drag, and eclipses into account. When the spacecraft deviates significantly from the reference trajectory, a new reference is calculated through the same method to reach the target debris. When required, phasing is integrated into the transfer. During the mission, the phase of the spacecraft is adjusted to match that of the target debris at the end of the transfer by introducing intermediate waiting times. The robustness of the guidance scheme is tested in a high-fidelity dynamic model that includes thrust errors and misthrust events. The guidance algorithm performs well without requiring successive convex iterations. Monte Carlo simulations are conducted to analyze the impact of these thrust uncertainties on the guidance. Simulation results show that the proposed convex-MPC approach can ensure that the spacecraft can reach its target despite significant uncertainties and long-duration misthrust events.

关键词： Mathematical Optimization Active Debris Removal Model Predictive Control Monte Carlo Simulation guidance and navigational algorithms Orbital Elements Model predictive control Eclipses Duty cycle Electric Propulsion

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Safe guidance Scheme for Proximity Operations Forced Motion

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JOURNAL OF guidance CONTROL AND DYNAMICS 2024年第1期48卷 1-18页

作者： Borelli, Giacomo Gaias, Gabriella Colombo, Camilla Polytech Univ Milan Dept Aerosp Sci & Technol Via La Masa 34 I-20156 Milan Italy

Autonomous spacecraft proximity operations represent a key enabler for future mission architectures such as in-orbit servicing, active debris removal, object inspection, and in-orbit assembly. This work addresses safety concepts for the relative trajectory guidance design applicable to challenging proximity operations in the close-range domain. The relative orbital element framework is used to formulate safety checks that improve the trajectory's robustness in case of chaser's malfunctions or loss of control. Particularly, concepts of passive abort safety and active collision safety are applied to the trajectory design to maintain the chaser outside keep-out zones. These definitions are included within a guidance algorithm that exploits sequential convex programming to efficiently solve the fixed final time safety-constrained close-range rendezvous problem. Test cases of reconfiguration between stable relative orbits and synchronization to a rotating hold point are presented, highlighting the advantages in using these new safety concepts in terms of safety, trajectory insight, and formulation efficiency.

关键词： Sequential Convex Programming guidance and navigational algorithms Spacecraft guidance and Control Active Debris Removal Optimal Control Problem Satellites Flight Safety Rendezvous guidance Autonomous Rendezvous and Docking Path-Constrained Rendezvous

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Online Corrections to Neural Policy guidance for Pinpoint Powered Descent

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JOURNAL OF guidance CONTROL AND DYNAMICS 2024年第5期47卷 945-963页

作者： Cho, Namhoon Shin, Hyo-Sang Tsourdos, Antonios Amato, Davide Cranfield Univ Ctr Autonomous & Cyber Phys Syst Sch Aerosp Transport & Mfg Cranfield MK43 0AL England Cranfield Univ Ctr Autonomous & Cyber Phys Syst Sch Aerosp Transport & Mfg Guidance Nav & Control Cranfield MK43 0AL England Imperial Coll London Fac Engn Dept Aeronaut Spacecraft Engn London SW7 2AZ England

This study presents incremental correction methods for refining neural network parameters or control functions entering into a continuous-time dynamic system to achieve improved solution accuracy in satisfying the interim point constraints placed on the performance output variables. The proposed approach is to linearize the dynamics around the baseline values of its arguments and then to solve for the corrective input required to transfer the perturbed trajectory to precisely known or desired values at specific time points, in other words, the interim points. Depending on the type of decision variables to adjust, parameter correction and control function correction methods are developed. These incremental correction methods can be used as a means to compensate for the prediction errors of pretrained neural networks in real-time applications where high accuracy of the prediction of dynamical systems at prescribed time points is imperative. In this regard, the online update approach can be useful for enhancing overall targeting accuracy of finite-horizon control subject to point constraints using a neural policy. A numerical example demonstrates the effectiveness of the proposed approach in an application to a powered descent problem on Mars.

关键词： Artificial Neural Network Finite Horizon Optimal Control guidance, Navigation, and Control Systems Representation Learning Entry, Descent, and Landing guidance and navigational algorithms Neural Ordinary Differential Equations Powered Descent guidance Incremental Correction Sensitivity

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Rocket Landing guidance Based on Linearization-Free Convexification

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JOURNAL OF guidance CONTROL AND DYNAMICS 2024年第2期47卷 217-232页

作者： Yang, Runqiu Liu, Xinfu Song, Zhengyu Beijing Inst Technol Sch Aerosp Engn Beijing 100081 Peoples R China China Acad Launch Vehicle Technol Beijing 100076 Peoples R China

The landing problem of a reusable rocket is generally a highly constrained and nonconvex optimization problem. In this paper, we will convexify the problem without relying on any linearization. Specifically, we propose to quickly determine some of the state variables in advance so that the nonlinearity of the dynamics is greatly reduced, and then we accurately convexify the problem by change of variables and transformation of the optimization objective. This convexification process enables us to design an iterative algorithm that can converge very reliably, and the convergence does not rely on any trust region constraint. It should be highlighted that the algorithm is very efficient, generally taking just milliseconds to converge on a personal computer. Furthermore, by ensuring the recursive feasibility of calling the iterative algorithm in each guidance cycle, we can design a landing guidance algorithm that is able to achieve precise landing under various uncertainties and disturbances. Numerical examples are provided to demonstrate the high performance of the iterative algorithm and the landing guidance algorithm.

关键词： Rockets guidance and navigational algorithms Flight Path Angle Aerodynamic Coefficients Soft Landing Optimization Algorithm Convex Optimization Optimal Control Problem Reusable Launch Vehicle Powered Descent guidance

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