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Genetic Programming guidance for the Reentry Trajectory of the ReFEx Vehicle

Genetic Programming Guidance for the Reentry Trajectory of t...

2024 IAF Space Transportation Solutions and Innovations Symposium at the 75th International Astronautical Congress, IAC 2024

作者： Marchetti, Francesco Gutierrez, Jose Luis Redondo Seelbinder, David Department of Guidance Navigation and Control Systems German Aerospace Centre (DLR) Institute of Space Systems Bremen Germany

ISBN: (纸本)9798331312244

In this work Genetic Programming (GP) is used to obtain an alternative guidance law for online trajectory adaptation of the Reusability Flight Experiment (ReFEx) reentry vehicle. GP is an Evolutionary Algorithm (EA) capable of producing interpretable mathematical models that satisfies user defined objectives and constraints. It can be applied in a guidance setting, through direct interaction with the environment, learning to evolve a the guidance law to steer the vehicle towards the successful satisfaction of the mission. To the best of the authors' knowledge, the application of GP to a flight-ready vehicle represents a first in this domain and can help in increasing the TRL of this technique for guidance and Control (G&C) applications. Furthermore, it produces interpretable models, in contrast to other Machine Learning (ML) approaches, and it can be applied to nonlinear models, in contrast with traditional methods. In this study, GP is applied offline to design an feedback guidance law to guide the ReFEx vehicle towards a desired final position in the presence of uncertainties in the physical models, navigation and control signals. The performance of the GP-based guidance law is compared against the current design, which defines the trajectory correction as an optimal control problem and reduces it to a nonlinear unconstrained optimization problem, which is then solved using a successive linearization strategy. The performance comparison between the two methods utilizes high fidelity 6-DoF Monte Carlo simulations. Capabilities, advantages and disadvantages of both methods are discussed and conclusions on the viability of the investigated GP approach are drawn. © 2024 International Astronautical Federation, IAF. All rights reserved.

关键词： Genetic Programming guidance Machine Learning Reusable Launch Vehicle

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A tracking guidance method with funnel scheduling for Mars landing

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AEROSPACE SCIENCE AND TECHNOLOGY 2024年 155卷

作者： Liu, Yunzhao Wang, Mingming Luo, Jianjun Li, JiaKe Cheng, Xuebin Ding, Jishiyu Sun, Kewu Northwestern Polytech Univ Natl Key Lab Aerosp Flight Dynam Xian 710072 Peoples R China Intelligent Sci & Technol Acad Ltd CASIC Beijing 100043 Peoples R China

Powered descent guidance is an enabling technology for extraterrestrial soft landing and reusable rocket recovery. Although the focus of guidance research has tilted towards trajectory optimization recently, feedback tracking control is still necessary to suppress the effects of flight perturbations and uncertainties. In this paper, for the Mars landing mission, the behavior of the powered descent closed-loop system is considered and a guidance method based on funnel (finite-time invariant set) scheduling is proposed. Firstly, the basic model of the powered descent problem is given and its state feedback closed-loop system is constructed. Subsequently, considering the thrust uncertainty as well as saturation constraints, the powered descent funnel model is established, and a point-by- point computation method based on Sum of Squares Programming (SOSP) is presented. On this basis, multiple nominal trajectories and their nearby funnels are solved. The guidance scheme based on funnel scheduling is formulated, which utilizes the funnels to provide a good basis for tracking different nominal trajectories, enhancing the adaptability to the initial state dispersions. The simulation results show that for the thrust deviation considered, the states within the funnel inlet can ensure convergence. The similar level of performance on fuel consumption and terminal accuracy of funnel scheduling guidance with convex programming guidance implies the bottleneck in feedback control performance.

关键词： guidance Funnel Mars landing Sum of squares programming Tracking control State feedback

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Adaptive learning: toward an intentional model for learning process guidance based on learner's motivation

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SMART LEARNING ENVIRONMENTS 2022年第1期9卷 33页

作者： Bayounes, Walid Saadi, Ines Bayoudh Kinsuk Manouba Univ RIADI Res Lab ENSI Manouba 2010 Tunisia Univ North Texas Coll Informat 1155 Union Cir Denton TX 76203 USA

The goal of ITS is to support learning content, activities, and resources, adapted to the specific needs of the individual learner and influenced by learner's motivation. One of the major challenges to the mainstream adoption of adaptive learning is the complexity and time involved in guiding the learning process. To tackle these problems, this research proposes an intentional model that adopts Map formalism to support personalized learning guidance by considering learner's motivation. For that, the intentional model adopts the ARCS model of motivation. The proposed model couples the learner's intention with the learning strategies and provides a multitude of paths between learner intentions. Based on the learner's motivation and the corresponding learning mode or the individual learning style, the ITS can adaptively support the learner to achieve his/her intention through the selected strategy. The first results show that this study's provide implications for both theoretical research and the practical development of ITSs that will help education professionals make full use of ITSs. In the initial tests, the process model has met what was expected, however, more studies with experiments must be carried out.

关键词： Intelligent tutoring system guidance Motivation Learning process Intentional model ARCS model

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Artificial intelligence for spacecraft guidance, navigation, and control: a state-of-the-art

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Aerospace Systems 2022年第4期5卷 503-521页

作者： Habib, Tamer Mekky Ahmed National Authority for Remote Sensing and Space Sciences Cairo Egypt

This article reviews state-of-the-art of the problem of using Artificial Intelligence (AI) for spacecraft guidance, Navigation, and Control (GNC). Developing AI algorithms for GNC purposes with enhanced and robust performance depends heavily on the models used for GNC algorithms. This is because using AI algorithms may require the designer to train his algorithms using training examples (data sets) via a supervised learning (SL) algorithms. GNC algorithms could be used to provide AI algorithms with the required data sets of training. So, reviewing state-of-the-art GNC algorithms is also mandatory. Good and up-to-date understanding of the current state-of-the art of GNC algorithms enable us to build better survey of using AI algorithms in spacecraft GNC. Unsupervised learning, or reward-based learning algorithms could also be used also for GNC purposes. The current article focuses on GNC algorithms, AI algorithms, and the interaction among AI and GNC algorithms. In addition, a future vision of using AI techniques with GNC is also provided. © 2022, Shanghai Jiao Tong University.

关键词： Artificial intelligence Control guidance Navigation Spacecraft

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Approach and landing guidance using constrained model predictive static programming

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AEROSPACE SCIENCE AND TECHNOLOGY 2024年 144卷

作者： Hameed, Aysha S. Bindu, G. R. Vutukuri, Srianish Coll Engn Trivandrum Dept Elect Engn Thiruvananthapuram Kerala India Indian Inst Sci Dept Aerosp Engn Bangalore India APJ Abdul Kalam Technol Univ Coll Engn Trivandrum Thiruvananthapuram Kerala India

The paper proposes a guidance scheme during the approach and landing phase of an unpowered vehicle to achieve high precision at touchdown by limiting the control inputs within allowable bounds using constrained Model Predictive Static Programming. The advantages of a single flight phase are incorporated into the design since the guess control history is obtained from a single segment based guidance approach. The requirement of ensuring continuity in states and guidance commands are hence avoided leading to minimization of control deviations using a simple cost function. Constrained input commands are used for determining control surface deflection based on dynamic inversion considering the longitudinal pitch rate dynamics. Comparison is carried out between the results obtained for constrained as well as unconstrained schemes for the nominal trajectory. Comparisons of load factor, dynamic pressure and flight path angle for three segment, two segment, single segment guidance strategies have been carried out with MPSP based guidance to evaluate the relative advantages offered by the scheme. Performance analysis of the proposed scheme is done based on numerous simulations with simultaneous variations in initial states, vehicle parameters and aerodynamic parameter variations. Simulation results indicate that the proposed scheme is suitable for landing on runways of shorter lengths due to minimal touchdown errors.

关键词： Approach and landing Constrained model predictive static programming Unpowered reusable launch vehicles guidance Dynamic inversion

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Meaning, Rationality, and guidance

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PHILOSOPHICAL QUARTERLY 2022年第1期73卷 227-247页

作者： Sultanescu, Olivia Univ Chicago Chicago IL 60637 USA

In Wittgenstein on Rules and Private Language, Saul Kripke articulates a form of scepticism about meaning. Even though there is considerable disagreement among critics about the reasoning in which the sceptic engages, there is little doubt that he seeks to offer constraints for an adequate account of the facts that constitute the meaningfulness of expressions. Many of the sceptic's remarks concern the nature of the guidance involved in a speaker's meaningful uses of expressions. I propose that we understand those remarks as seeking to give shape to the idea that to use an expression under the guidance of one's understanding is to have a reason for that use, which one's understanding allows one to discern and act on. Any philosophical elucidation of meaning must adequately capture the rational nature of our linguistic acts.

关键词： meaning scepticism normativity rationality guidance semantic non-reductionism

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The role of guidance in delivering cardiac resynchronization therapy: A systematic review and network meta-analysis

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HEART RHYTHM O2 2022年第5期3卷 482-492页

作者： Mehta, Vishal S. Ayis, Salma Elliott, Mark K. Widjesuriya, Nadeev Kardaman, Nuha Gould, Justin Behar, Jonathan M. Chiribiri, Amedeo Razavi, Reza Niederer, Steven Rinaldi, Christopher A. Guys & St Thomas NHS Fdn Trust Dept Cardiol London England Kings Coll London Sch Biomed Engn & Imaging Sci London England Kings Coll London Sch Populat Hlth & Environm Sci London England

BackgroundPositioning the left ventricular lead at the optimal myocardial segment has been proposed to improve cardiac resynchronization therapy (CRT) response. ObjectivesWe performed a systematic review and network meta-analysis evaluating echocardiographic and clinical response delivered with different guidance modalities compared to conventional fluoroscopic positioning. MethodsRandomized trials with ≥6 months follow-up comparing any combination of imaging, electrical, hemodynamic, or fluoroscopic guidance were included. Imaging modalities were split whether one modality was used: cardiac magnetic resonance (CMR), speckle-tracking echocardiography (STE), single-photon emission computed tomography, cardiac computed tomography (CT), or a combination of these, defined as “multimodality imaging.” ResultsTwelve studies were included (n = 1864). Pair-wise meta-analysis resulted in significant odds of reduction in left ventricular end-systolic volume (LVESV) >15% (odds ratio [OR] 1.50, 95% confidence interval [CI] 1.05–2.13, P = .025) and absolute reduction in LVESV (standardized mean difference [SMD] -0.25, 95% CI -0.43 to -0.08, P = .005) with guidance. CMR (OR 55.3, 95% CI 4.7–656.9, P = .002), electrical (OR 17.0, 95% CI 2.9–100, P = .002), multimodality imaging (OR 4.47, 95% CI 1.36–14.7, P = .014), and hemodynamic guidance (OR 1.29–28.0, P = .02) were significant in reducing LVESV >15%. Only STE demonstrated a significant reduction in absolute LVESV (SMD -0.38, 95% CI -0.68 to -0.09, P = .011]. CMR had the highest probability of improving clinical response (OR 17.9, 95% CI 5.14–62.5, P < .001). ConclusionOverall, guidance improves CRT outcomes. STE and multimodality imaging provided the most reliable evidence of efficacy. Wide CIs observed for results of CMR guidance suggest more powered studies are required before a clear ranking is possible.

关键词： Cardiac resynchronization therapy LV lead guidance Efficacy Systematic review Meta-analysis

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How does career guidance at schools encounter migrant young people? Interactional practices that hinder socially just guidance

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INTERNATIONAL JOURNAL FOR EDUCATIONAL AND VOCATIONAL guidance 2022年第2期22卷 449-466页

作者： Vehvilainen, Sanna Souto, Anne-Mari Univ Eastern Finland POB 111 Joensuu 80101 Finland

The aim of this article is to show how interaction research can contribute to the understanding and praxis of socially just guidance. The article is theoretical, but it makes use of our previous empirical studies. We combine the ethnographic study of school and racism, and interactional research on guidance. We define guidance for social justice, explaining how this translates to the level of interactional practices. We show two empirical examples of interactional phenomena hindering socially just praxis. We lastly discuss our practical conclusions on how to help school career counsellors change their interactional practices.

关键词： guidance School career counselling Young migrant students guidance interaction Social justice Migration guidance for social justice

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Co-adaptive visual data analysis and guidance processes

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COMPUTERS & GRAPHICS-UK 2021年 100卷 93-105页

作者： Sperrle, Fabian Jeitler, Astrik Bernard, Juergen Keim, Daniel El-Assady, Mennatallah Univ Konstanz Constance Germany Univ Zurich Zurich Switzerland

Mixed-initiative visual data analysis processes are characterized by the co-adaptation of users and sys-tems over time. As the analysis progresses, both actors - users and systems - gather information, up-date their analysis behavior, and work on different tasks towards their respective goals. In this paper, we contribute a multigranular model of co-adaptive visual analysis that is centered around incremental learning goals derived from a hierarchical taxonomy of learning goals from pedagogy. Our model captures how both actors adapt their data-, task-, and user/system-models over time. We characterize interaction patterns in terms of the dynamics of learning and teaching that drive adaptation. To demonstrate our model's applicability, we outline aspects of co-adaptation in related models of visual analytics and high-light co-adaptation in existing applications. We further postulate a set of expectations towards adaptation in mixed-initiative processes and identify open research questions and opportunities for future work in co-adaptation. (c) 2021 Elsevier Ltd. All rights reserved.

关键词： Co-Adaptive Analysis Process guidance Visual Analytics

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How to Guide Task-oriented Chatbot Users, and When: A Mixed-methods Study of Combinations of Chatbot guidance Types and Timings 22

How to Guide Task-oriented Chatbot Users, and When: A Mixed-...

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CHI Conference on Human Factors in Computing Systems (CHI)

作者： Yeh, Su-Fang Wu, Meng-Hsin Chen, Tze-Yu Lin, Yen-Chun Chang, Xi-Jing Chiang, You-Hsuan Chang, Yung-Ju Natl Yang Ming Chiao Tung Univ Hsinchu Taiwan Univ Toronto Toronto ON Canada

ISBN: (纸本)9781450391573

The popularity of task-oriented chatbots is constantly growing, but smooth conversational progress with them remains profoundly challenging. In recent years, researchers have argued that chatbot systems should include guidance for users on how to converse with them. Nevertheless, empirical evidence about what to place in such guidance, and when to deliver it, has been lacking. Using a mixed-methods approach that integrates results from a between-subjects experiment and a reflection session, this paper compares the effectiveness of eight combinations of two guidance types (example-based and rule-based) at four guidance timings (service-onboarding, task-intro, after-failure, and upon-request), as measured by users' task performance, improvement on subsequent tasks, and subjective experience. It establishes that each guidance type and timing has particular strengths and weaknesses, thus that each type/timing combination has a unique impact on performance metrics, learning outcomes, and user experience. On that basis, it presents guidance-design recommendations for future task-oriented chatbots.

关键词： chatbot lab study non-progress guidance

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