Robert Fonod

Robert Fonod
École Polytechnique Fédérale de Lausanne | EPFL · Urban Transport Systems Laboratory

PhD

About

34
Publications
11,211
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251
Citations

Publications

Publications (34)
Article
Full-text available
This paper deals with the design and validation of an active fault-tolerant control system to detect, isolate and accommodate a single thruster fault affecting the thruster-based propulsion system of an autonomous spacecraft. The proposed method consists of a fault detector for robust and quick fault detection, a two-stage hierarchical isolation st...
Article
Full-text available
The recently published optimal Cauchy estimator poses practical implementation challenges due to its time-growing complexity. Alternatively, addressing impulsive measurement and process noises, while using common estimation approaches, requires heuristic schemes. Approximate methods, such as particle and Gaussian-sum filters, were suggested to tack...
Article
A novel wingman-based estimation and guidance concept is proposed for a sensorless pursuer. The pursuer is guided towards a maneuvering aerial target using proportional navigation (PN) guidance law. The wingman is assumed to acquire bearings-only measurements of the target and to accurately track the wingman-pursuer relative position. The pursuer-t...
Article
Full-text available
DeepSleep 2.0 is a compact version of DeepSleep, a state-of-the-art, U-Net-inspired, fully convolutional deep neural network, which achieved the highest unofficial score in the 2018 PhysioNet Computing Challenge. The proposed network architecture has a compact encoder/decoder structure containing only 740,551 trainable parameters. The input to the...
Article
Full-text available
The relative pose estimation of an inactive spacecraft by an active servicer spacecraft is a critical task in the design of current and planned space missions, due to its relevance for close-proximity operations, such as In-Orbit Servicing and Active Debris Removal. This paper introduces a novel framework to enable robust monocular pose estimation...
Conference Paper
Full-text available
This paper introduces a novel framework which combines a Convolutional Neural Network (CNN) for feature detection with a Covariant Efficient Procrustes Perspective-n-Points (CEPPnP) solver and an Extended Kalman Filter (EKF) to enable robust monocular pose estimation for close-proximity operations around an uncooperative spacecraft. The relative po...
Conference Paper
Full-text available
Fast and large-angle attitude slew maneuvers often imply simultaneous use of multiple actuators such as thrusters and reaction wheels (RWs). A fault in any of these actuators might lead to partial or full damage of sensitive spacecraft instruments. In this paper, a model-based Fault Detection and Isolation (FDI) strategy is proposed, which aims at...
Conference Paper
Full-text available
This paper reports on a comparative assessment of Image Processing (IP) techniques for the relative pose estimation of uncooperative spacecraft with a monocular camera. Currently, keypoints-based algorithms suffer from partial occlusion of the target, as well as from the different illumination conditions between the required offline database and th...
Article
Full-text available
The relative pose estimation of an inactive target by an active servicer spacecraft is a critical task in the design of current and planned space missions, due to its relevance for close-proximity operations, i.e. the rendezvous with a space debris and/or in-orbit servicing. Pose estimation systems based solely on a monocular camera are recently be...
Conference Paper
Full-text available
The problem of pure magnetic detumbling of a fast-tumbling picosatellite is considered. A new weighted B-dot control algorithm is proposed. The algorithm enables power reduction while not sacrificing detumbling performance. Analytical expressions relating the maximal expected rotational rate to the minimum sampling time required are presented. Simu...
Article
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A novel cooperative defensive guidance law is presented for a two-on-two engagement. Instead of classical strategies in which evasive maneuvers are performed or additional agents (e.g., defender missiles) are deployed, the target pair lures the pursuing missiles into collision. The optimal cooperative strategy is solved using state-dependent Riccat...
Article
A novel “blind and evade” guidance concept for an aerial target which is exposed to a threat of two homing missiles is presented. Each missile is assumed to measure solely its own line-of-sight (LOS) angle and share it with the other missile. Such information sharing enables the missiles to form a triangular measuring baseline relative to the targe...
Article
Full-text available
Cooperative estimation/guidance for a team of missiles is the topic of this paper. An example scenario is considered where an aircraft simultaneously launches several cooperative defending missiles as a countermeasure against an attacking homing missile. A new reduced-order estimation scheme based on information sharing to cooperatively estimate th...
Conference Paper
Full-text available
A multiple-body interception scenario is considered, where an evading target aircraft launches two defending missiles as a countermeasure against an incoming homing missile. The defenders share their respective line of sight angle measurements, are aware of the target’s evasion strategy, and exploit a cooperate guidance law which can impose a relat...
Data
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Conference Paper
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In this paper, a multiple model adaptive evasion strategy for a target aircraft from a homing missile employing a linear guidance law is proposed. We assume arbitrary-order linear missile and target dynamics, bounded target control, nonlinear kinematics, and the missile employing one of a finite set of possible guidance laws. Specific cases are num...
Conference Paper
Full-text available
Only few estimation methods can converge in the presence of impulsive measurement and/or process noises without the use of augmented heuristic schemes. To understand the performance of these schemes, the optimal Idan/Speyer Cauchy Estimator (ISCE) is compared with the performance of the particle filter (PF) and Gaussian sum filter (GSF) as the conv...
Article
Full-text available
Multiple model adaptive evasion strategies from an incoming homing missile are presented. The problem is formulated in the context of an evading target aircraft having imperfect information on the relative state and on the employed guidance law and guidance parameters of the missile. The missile’s guidance strategy is assumed to belong in a finite...
Article
Full-text available
This paper deals with performance and reliability evaluation of a fault diagnosis scheme based on two distinct models to detect and isolate a single thruster fault affecting a chasing spacecraft during rendezvous with a passive target in a circular orbit. The analysis is conducted in the frame of a terminal rendezvous sequence of the Mars Sample Re...
Thesis
Les travaux de recherche traités dans cette thèse s’appuient sur l’expertise des actionsmenées entre l’Agence spatiale européenne (ESA), l’industrie Thales Alenia Space (TAS) et le laboratoirede l’Intégration du Matériau au Système (IMS) qui développent de nouvelles générations d’unités intégréesde guidage, navigation et pilotage (GNC) avec une fon...
Thesis
Full-text available
The work addressed in this thesis draws expertise from actions undertaken between the EuropeanSpace Agency (ESA), the industry Thales Alenia Space (TAS) and the IMS laboratory (laboratoirede l’Intégration du Matériau au Système) which develop new generations of integrated Guidance, Navigationand Control (GNC) units with fault detection and toleranc...
Conference Paper
Full-text available
The presented work is a result of a research collaboration between European Space Agency, Thales Alenia Space and IMS Laboratory with the aim of promoting fault-tolerant control strategies to advance spacecraft autonomy. A multiple observer based scheme is proposed jointly with an online constrained allocation algorithm to detect, isolate and accom...
Conference Paper
Full-text available
In this paper, the problem of Nonlinear Unknown Input Observer (NUIO) based Fault Detection and Isolation (FDI) scheme design for a class of nonlinear Lipschitz systems is studied. The proposed FDI method is applied to detect, isolate and accommodate thruster faults of an autonomous spacecraft involved in the rendezvous phase of the Mars Sample Ret...
Conference Paper
Full-text available
Two robust fault detection schemes are presented to detect faults affecting the thrust system of the chaser spacecraft involved in the rendezvous phase of the Mars Sample Return (MSR) mission. The idea of both proposed methods is to transform the unstructured uncertainty caused by the electronic induced delays into unknown inputs and decouple them...
Conference Paper
Full-text available
This paper addresses robust fault diagnosis of the chaser's thrusters used for the rendezvous phase of the Mars Sample Return (MSR) mission. The MSR mission is a future exploration mission undertaken jointly by the National Aeronautics and Space Administration (NASA) and the European Space Agency (ESA). The goal is to return tangible samples from M...
Conference Paper
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A problem of robust fault diagnosis of digital controlled continuous-time systems with uncertain time-varying input delay is studied in this paper. Two residual-based fault detection and isolation (FDI) schemes are proposed that are robust in terms of time-varying delays induced by the electronic devices and disturbances. The idea of both proposed...
Conference Paper
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Reformulated principle for designing actuator fault estimation for continuous-time linear MIMO systems, based on neuro-sliding mode observer structure, is presented in this paper. Radial basis function neural network is used as a model-free fault approximator of the unknown additive fault. The method utilizes Lyapunov function and the steepest desc...
Conference Paper
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This paper is concerned with the problem of stabilization for continuous-time systems with distributed time delays. Using an extended form of the Lyapunov-Krasovskii functional the controller design conditions are derived with respect to application of structured matrix variables in linear matrix inequalities. The result giving a sufficient conditi...
Article
Full-text available
Systems with delays are a specific group of dynamic systems. The fact that some delays can be short and some can be long makes system analysis and control design much more complex. In this paper we present a proposal to solve the problem of stability and control design of continuous time systems with time-varying delays. Based on the Lyapunov-Kraso...
Conference Paper
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In this paper the design of controlling a class of linear systems via state feedback eigenstructure assignment is investigated. The design aim is to synthesize a state feedback control law such that for prescribed eigenvalues of the closed-loop control system corresponding eigenvectors are as close to decoupled ones as possible. The set of parametr...
Conference Paper
Full-text available
Reformulated principle of fault estimation design for one class of first order continuous-time nonlinear system is treated in this paper, where a neural network is regarded as model-free fault approximator. The problem addressed is presented as approach based on sliding mode methodology with combination of radial basis function neural network to de...
Article
Full-text available
The presented design method aim is to synthesize a state feedback control law in such way that with respect to the prescribed eigenvalues of the closed-loop system matrix the corresponding eigenvectors are as close as possible to a decoupled system eigenvectors. It is demonstrated that some degree of freedom existing in the control design, represen...

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