A growing population is driving automatization in agricultural industry to strive for more productive arable land. Being part of this process, this work is aimed to investigate the possibility to implement sensor-based automation in a particular system called Front End Loader, which is a lifting arms that is commonly mounted on the front of a tractor. Two main tasks are considered here, namely Electronic Self Leveling (ESL) and payload estimation. To propose commercially implementable solutions for these tasks, specific objectives are set, which are: 1) to propose a controller to perform ESL under typical disturbances 2) to propose a methodology for payload estimation considering realistic estimation conditions. Lastly, aligned with these goals, 3) to propose models for the Front End Loader under consideration for derivation of solutions of the specified tasks. The self-leveling task assists farmers in maintaining the angular position of the mounted implements, e.g. a bale handler or a bucket, with respect to the ground when the loader is manually lifted or lowered. Experimental results show that different controllers are required in lifting and lowering motions to maintain the implement's angular position with a required accuracy due to principle differences in gravity impact. The gravity helps the necessary correction in lifting motion, but works against the correction in lowering motions. This led us to propose a controller with a proportional term, a discontinuous term and an on-line disturbance estimation and compensation as well as the tuning procedure to achieve a 2 degrees tracking error for lowering motions in steady state. The proposed controller shows less sensitive performance to lowering velocity, as the main disturbance, in comparison to a linear controller. The second task, payload estimation, assists farmers to work within safety range as well as to work with a weight measurement tool. A mechanical model derived based on equations of motion is improved by a pressure based friction to sufficiently accurately represent the motion of the front end loader under consideration. The proposed model satisfies the desired estimation accuracy of 2\% full scale error in a certain estimation condition domain in constant velocity regions, with off-line calibration step and off-line payload estimation step. An on-line version of the estimation based on Recursive Least Squares also fulfills the desired accuracy, while keeping the calibration step off-line.

Aerial lifts are used to elevate people and material to high heights. There are many different types of aerial lifts which have vastly different dynamics characteristics. Thus, a new categorization for aerial lifts was created and organizes them by their kinematics. Many accidents occur while using aerial lifts. Hazards of aerial lifts and current solutions to those hazards were reviewed to understand the causes of the accidents. Some major accidents are due to the complex dynamics and flexibility of aerial lifts, such as oscillations and tip-overs. Oscillations of full-size aerial lifts were experimentally tested to determine frequencies in different configurations. Machine-motion induced oscillations of an articulating aerial lift were simulated and analyzed for both non-overcenter and overcenter configurations. Input shaping was used to achieve reduction in machine-motion induced oscillations. Tip-over stability margin was used to simulate and analyze the stability of both non-overcenter and overcenter configurations. The effect of increased platform mass on tip-over stability margin was also analyzed. The results in this thesis are a categorization of aerial lifts including their hazards and methods of reducing those hazards, an experimental verification of the dynamic response of full-size aerial lifts, a fully dynamic tip-over prediction model of double-boom articulating aerial lift by applying flexibility in the joints and realistic velocity profiles, and a detailed study of the dynamics of a double-boom articulating aerial lift.

Les télécommunications par satellite prennent aujourd’hui de en plus d’importance, et le nombre d’abonnés à travers le monde ne cesse de croître. Partout où la fibre optique ne peut être déployée, elles sont un moyen fiable de fournir des débits très élevés aux utilisateurs, dont les pratiques nécessitent des bandes passantes toujours plus importantes (vidéo HD, visioconférences, téléchargement, cloud computing, jeux en ligne...). Elles garantissent également de très vastes zones de couverture. Pour les concepteurs de charges utiles de satellite, suivre les besoins du marché revient à augmenter constamment le nombre d’équipements embarqués, ce qui affecte le volume et la masse des systèmes et donc le coût de mise en orbite. Une des solutions envisagées afin de contrer ce phénomène consiste à employer des technologies optiques. Il a été démontré par Thales Alenia Space que pour un système de distribution de signaux de référence de 1 vers 64 équipements, la réduction du poids pourrait être de 70 %. Dans ce contexte nous avons développé 7 convertisseurs de fréquence RF réalisés à partir de composants photoniques semi-conducteurs. Ces convertisseurs font partie des composants clés des charges utiles car ils permettent d’isoler les transmissions montantes (vol vers satellite) et descendantes (satellite vers sol) afin d’éviter les interférences. Les performances des 7 architectures proposées, réalisées à partir de modulateurs électro-absorbants (EAM) et d’amplificateurs optiques à semi-conducteurs (SOA) ont été évaluées au travers de différentes simulations et en calculant le gain de conversion, le facteur de bruit, les isolations RF/FI et OL/FI, les rapports C/I3 et les coordonnées du point d’interception d’ordre 3. Nous avons obtenu des performances intéressantes, premières données pour de futures études et montré que ces convertisseurs seraient compatibles avec de nombreux plans de fréquence en bandes Ku/Ku, Ku+/Ku, et Ka/Ka. Des manipulations ont également permis de valider les modèles théoriques employés dans les simulations. / Nowadays, Satellite telecommunications are becoming very popular and the number of subscribers worldwide is always growing. Wherever the optical fiber cannot be deployed, they are a reliable way to provide very high data rates to the users, whose activities are becoming more and more bandwidth-hungry (HD video, video conferencing, downloading, cloud computing, online games ...). They also guarantee very large coverage areas. In order to follow the market needs satellite payload designers have to increase the number of on-board equipment, which affects the volume and mass of the systems and therefore the launching cost. One of the solutions to solve the problem consists in using optical technologies. It has been demonstrated by Thales Alenia Space that In the case of a reference signal distribution system for 64 devices, a weight reduction of about 70% could be obtained. In this context we have developed 7 RF frequencydown-converters based on photonic semiconductor components. The down-converters are key components of satellite payloads, as their aim is to isolate uplink transmissions (ground to satellite) and downlink (satellite to ground) to avoid interference. Performance of the 7 architectures, incorporating electro-absorption modulators (EAM) and semiconductor optical amplifiers (SOA) were evaluated through various simulations and by calculating the conversion gain, noise figure, RF/IF and LO/IF isolations, the C/I3 ratio and the coordinates of the third order intercept point. We obtained interesting results, first data for futur works,and showed that these converters are compatible with many frequency plans in Ku/Ku, ku+/Ku, and Ka/Ka bands. Manipulations were also led and validated the theoretical models used in simulations.

This paper will focus solely on the effectiveness of AV (antivirus) in detecting Metasploit payloads which have been encapsulated with different encapsulation modules. There seems to be a significant knowledge gap in the evaluation of commercial antivirus's software and their ability to detect malicious code and stop such code from being executed on IT systems. Therefore we would like to evaluate the capabilities of modern AV software with the use of penetration testing tools such as Metasploit. The research process is heavily reliant on a case study methodology as it can be argued that each payload generated reflects a case in itself. Firstly the payloads are generated and encapsulated through the self developed software, secondly they are uploaded to VirusTotal to be scanned with the use of their publicly available API, third the results are obtained from VirusTotal and stored locally. Lastly the results are filtered through with the software which in turn generates graphs of the results. These results will provide sufficient data in comparing encapsulation methods, payload detection rates, draw conclusions regarding which operating system may be most vulnerable as well as the overall state of modern AV software's capabilities in detecting malicious payloads. There are plenty of noteworthy conclusions to be drawn from the results, one of them being the most efficient encapsulation method powershell_base64 which had amongst the lowest detection rates in regards to the amounts of payloads it encoded, meaning that its encapsulation hid the malicious code from the AV at a higher degree than most the other encapsulation modules. The most noteworthy conclusion from the results gathered however is the encapsulation methods which obtained the absolute lowest detection rates, these were x86_nonalpha, x86_shikata_ga_nai, x86_xor_dynamic as well as payloads without any encoding at all, which had a few payloads reach among the lowest detection rates across the board (<20%).

Robot arms require actuators that are powerful, precise and safe. The safety concern is amplified when these robots work closely with people in collaborative applications. This thesis investigates the design and implementation of hybrid pneumatic-electric actuators (HPEA) for use in robot arms, particularly those intended for collaborative applications. The initial focus was on improving the control of an existing single HPEA-driven rotary joint. The torque is produced by four pneumatic cylinders connected in parallel with a small DC motor. The DC motor is directly connected to the output shaft. A cascaded control system is designed that consists of an outer position control loop and an inner pressure control loop. The pressure controller is based on a novel inverse valve model. High precision position tracking control is achieved due to the combination of the model-based pressure controller, model-based position controller, adaptive friction compensator and offline payload estimator. Experiments are performed with the actuator prototype rotating a link and payload with a rotational inertia equivalent to a linear actuator moving a 573 kg mass. Averaged over five tests, a root-mean-square error of 0.024° and a steady-state error (SSE) of 0.0045° are achieved for a fast multi-cycloidal trajectory. This SSE is almost ten times smaller than the best value reported for previous HPEAs. An offline payload estimation algorithm is used to improve the control system’s robustness. The superior safety of the HPEA is shown by modeling and simulating a constrained robot-head impact, and comparing the result with equivalent electric and pneumatic actuators. This research produced two journal papers. Since HPEAs are redundant actuators that combine the large force, low bandwidth characteristics of pneumatic actuators with the large bandwidth, small force characteristics of electric actuators, the effect of using optimization-based input allocation for HPEAs was studied. The goal was to improve the HPEA’s performance by distributing the required input (force or torque) between the redundant actuators in accordance with each actuator’s advantages and limitations. Three novel model-predictive control (MPC) approaches are designed to solve the position tracking and input allocation problems using convex optimization. The approaches are simulated on a HPEA-driven system and compared to a conventional linear controller without active input allocation. The first MPC approach uses a model that includes the dynamics of the payload and pneumatics; and performs the motion control using a single loop. The latter methods simplify the MPC law by separating the position and pressure controllers. Although the linear controller is the most computationally efficient, it is inferior to the MPC-based controllers in position tracking and force allocation performance. The third MPC-based controller design demonstrated the best position tracking with root mean square errors of 46%, 20%, and 55% smaller than the other three approaches. It also demonstrated sufficient speed for real-time operation. This research produced one journal paper. The research continued with the design and implementation of a two degree-of-freedom HPEA-driven arm. A HPEA-driven “elbow” joint is designed and added to the existing “shoulder” joint. The force from a single pneumatic cylinder is converted into torque using a 4-bar linkage. To eliminate backlash and keep the weight of the arm low, a 2nd smaller DC motor is directly connected to the joint. The kinematic and kinetic models of the new arm, as well as the geometry of the new elbow joint are studied. The resulting joint design is implemented, tested and controlled. This joint could achieve a SSE of 0.0045° in spite of its nonlinear joint geometry. The arm is experimentally tested for simultaneous tracking control of the two joints, and for end-effector position tracking in Cartesian space. The end-effector is able to follow a circular trajectory in pneumatic mode with position errors below 0.005 m. / Thesis / Doctor of Philosophy (PhD) / Robots that work with, or near, humans require greater safety considerations than other robots. A significant concern is collisions between the robot and humans that may happen when sensors or software fails. An actuator for robots that combines the inherent safety of pneumatic actuators with the accuracy of electric actuators, termed a “hybrid pneumatic electric actuator” (HPEA), is investigated. The design, instrumentation, modelling, and control of HPEAs are studied theoretically and experimentally. The proposed actuator could achieve high position control accuracy in a variety of experiments, with steady state error of less than 0.0045 degrees. Simulated impacts with a human head also showed that a HPEA-driven robot arm can achieve a 52% lower impact force, compared to an arm driven by conventional electric actuators. The HPEA design and control experiments are performed on a single HPEA-driven joint and extended to an arm consisting of two HPEA-driven revolute joints.

<p>Secondary payloads have a rich and successful history of utilizing cheap rides to orbit to perform outstanding missions in Earth orbit, and more recently, in cislunar space and beyond. New launch vehicles, namely the Space Launch System (SLS), are increasing the science opportunity for rideshare class missions by providing regular service to the lunar vicinity. However, trajectory design in a multi-body regime brings a host of novel challenges, further exacerbated by constraints generated from the primary payload’s mission. Often, secondary payloads do not possess the fuel required to directly insert into lunar orbit and must instead perform a lunar flyby, traverse the Earth-Moon-Sun system, and later return to the lunar vicinity. This investigation develops a novel framework to construct low-cost, end-to-end lunar transfer trajectories for secondary payload missions. The proposed threephase approach provides unique insights into potential lunar transfer geometries. The phases consist of an arc from launch to initial perilune, an exterior transfer arc, and a lunar approach arc. The space of feasible transfers within each phase is determined through low-dimension grid searches and informed filtering techniques, while the problem of recombining the phases through differential corrections is kept tractable by reducing the dimensionality at each phase transition boundary. A sample mission demonstrates the trajectory design approach and example solutions are generated and discussed. Finally, alternate strategies are developed to both augment the analysis and for scenarios where the proposed three-phase technique does not deliver adequate solutions. The trajectory design methods described in this document are applicable to many upcoming secondary payload missions headed to lunar orbit, including spacecraft with only low-thrust, only high-thrust, or a combination of both. </p>

The maneuverability and freedom provided by unmanned aerial vehicles (UAVs) make these an interesting choice for transporting objects in settings such as search and rescue operations, construction, and smart factories. A commonly proposed method of transport is by using cables attached between each UAV and the payload. However, the geometrical constraints posed by these attachments typically result in a system with highly complex dynamics. Although not an issue for conventional PID control schemes, these complex dynamics make the direct application of model predictive controllers (MPCs) infeasible for real-time usage. For this reason, much of the previous work has focused on treating the payload as a disturbance, thereby losing the ability to predict its effect on the UAVs. Contrary to this, this thesis presents an MPC that both captures the dynamics of the payload, and is capable of real-time usage. This is made possible by a parametrized linearization of the original system, and results in greatly improved performance compared to the disturbance model approach. The controller is derived for a system with two UAVs that transport a bar-like payload and verified both in simulations and physical experiments. The resulting control system is able track a multitude of setpoints, including rotations of both payload and UAVs, as well as lateral translations. Furthermore, it is able to attenuate external disturbances well, and dampens and prevents oscillations more efficiently when compared to the disturbance based approach. The resulting MPC solving time is on the order of milliseconds. Additionally, an initial attempt to decentralize the system is made, and the resulting controller experimentally tested on the UAV–bar system, resulting in a lower MPC solving time (2:5 times faster on average), but worsened performance in terms of position tracking of the bar. / Den manövrerbarhet och frihet som möjliggörs av användandet utav obemannade luftfarkoster (drönare) gör dessa till tämligen intressanta kandidater för lasttransport inom områden såsom sök- och räddningsuppdrag, byggnadskonstruktion och s.k. smarta fabriker. En vanligen förespråkad transportmetod består utav att förse systemet med kablar som fästs mellan last och drönare. De geometriska restriktioner som denna lastkoppling innebär resulterar emellertid ofta i system med väldigt komplicerad dynamik och interaktionskrafter. Även om detta inte innebär något problem för konventionella PID reglersystem så omöjliggör detta det direkta applicerandet utav modellprediktiv reglering (MPC) för realtidsbruk. Av denna anledning har tidigare verk fokuserat på att behandla lasten och dess inverkan på drönarna som en störning, men med detta därmed förlorat möjligheten att förutspå dess effekt på drönarna. I kontrast till detta, kommer det i detta verk att presenteras en MPC som både fångar lastens dynamik och är snabb nog för realtidsanvändning. Detta görs möjligt utav en parametriserad linjärisering utav originalsystemet och ger märkbart bättre resultat än den störningbaserade modellen. Reglersystemet appliceras på ett system bestående utav två drönare och en stång-liknande last och resultatet verifieras både i form av numeriska simuleringar och fysiska experiment. Det resulterande systemet klarar av både rotationer utav last och drönare samt translationer i alla riktningar. Dessutom är systemet kapabelt att hantera externa störningar och både dämpar och förhindrar oscillationer bättre i jämförelse med reglersystem baserat på störningsmodeller. Lösningstiden för MPC-regulatorn är i storleksordningen millisekunder. Utöver detta görs ett initialt försök i att decentralisera tidigare nämnda MPC och det resulterande reglersystemet utvärderas experimentellt på samma drönarsystem som tidigare. Detta resulterar i en lägre lösningstid (2.5 ggr snabbare i genomsnitt), men även i försämrad prestanda med avseende på reglering av stångens position.

Les fortes capacités actuelles et envisagées des futurs liens satellites de communication pour la 5G conduisent les signaux traités dans les charges utiles à présenter simultanément d'importantes variations d'amplitude (PAPR>10dB) et de très larges bandes passantes instantanées (BW>1GHz). A l'intérieur du sous-système d'émission hyperfréquence, le fonctionnement du module d'amplification de puissance se trouve très contraint par les formes d'ondes véhiculées, il se présente comme l'un des postes de consommation énergétique des plus importants, et ayant le plus d'impact sur l'intégrité du signal émis. Dans ce contexte, les fonctions dédiées au traitement numérique des signaux et couramment implémentées par le processeur numérique (telles que le filtrage, la canalisation, et éventuellement la démodulation et la régénération des signaux bande de base) embarquées dans les charges utiles, représentent une solution à fort potentiel qui permettrait de relâcher les contraintes reportées sur la fonction d'amplification de puissance afin de gérer au mieux la ressource électrique allouée. Ces travaux de thèse proposent d'étudier les potentialités d'amélioration du fonctionnement en rendement et linéarité d'un amplificateur de type Doherty à double entrée de gamme 20W en technologie GaN et fonctionnant en bande C. La combinaison des signaux de puissance sur la charge RF est optimisée par une distribution optimale des signaux en amplitude et phase à l'entrée par des moyens numériques de génération. Dans un premier temps une méthodologie de conception large bande d'un amplificateur Doherty est introduite et validée par la conception d'un démonstrateur en bande C. Dans un second temps, l'outil expérimental permettant l'extraction des lois optimales de distribution d'amplitude et de phase RF est présenté en détail, et la caractérisation expérimentale du dispositif en double entrée est réalisée puis comparée aux simulations. Finalement, en perspective à ces travaux, une étude préliminaire des potentialités de l'architecture Doherty à double entrée pour la gestion d’une désadaptation de la charge de sortie (gestion de TOS) est menée et des résultats sont mis en avant. / The high capabilities of current and future 5G communication satellite links lead the processed signals in the payloads to simultaneously exhibit large amplitude variations (PAPR>10dB) and wide instantaneous bandwidths (BW>1GHz). Within the microwave transmission subsystem, the operation of the power amplification stage is highly constrained by the transmitted waveforms, it is one of the most energy-consuming module of the payload affecting as well the integrity of the transmitted signal. In this context, the functions dedicated to digital signal processing and currently implemented by the digital processor (such as filtering, channeling, and possibly the demodulation and regeneration of baseband signals) embedded in the payloads, represent a potential solution that would reduce the constraints reported on the power amplification function and help to manage the allocated power ressource. This work proposes a study on the capability of dual input power amplifier architectures in order to manage the efficiency-linearity trade-off over a wide bandwidth. This study is carried out on a 20W GaN Doherty demonstrator operating in C band. The combination of the output signals on the RF load is managed by an optimal amplitude and phase distribution that is digitally controlled at the input. Firstly, a wideband design methodology of Doherty amplifier is introduced and validated on a C band demonstrator. In a second time the experimental tool allowing the extraction of amplitude and phase input distributions is presented, the dual input characterization is achieved and compared with simulation results. Finally, in perspective of this work, a preliminary study of the capabilities of the digital Doherty for the management of an output load mismatch (VSWR management) is carried out and the results are put forward.

International Telemetering Conference Proceedings / October 30-November 02, 1995 / Riviera Hotel, Las Vegas, Nevada / The UC Berkeley Extreme Ultraviolet Explorer (EUVE) Science Operations Center (ESOC) is developing and implementing knowledge-based software to automate the monitoring of satellite payload telemetry. Formerly, EUVE science payload data were received, archived, interpreted, and responded to during round-the-clock monitoring by human operators. Now, knowledge-based software will support, augment, and supplement human intervention. In response to and as a result of this re-engineering project, the creation, storage, revision, and communication of information (the information flow process) within the ESOC has been redesigned. We review the information flow process within the ESOC before, during, and after the re-engineering of telemetry monitoring. We identify six fundamental challenges we face in modifying the information flow process. (These modifications are necessary because of the shift from continuous human monitoring to a knowledge-based autonomous monitoring system with intermittent human response.) We describe the innovations we have implemented in the ESOC information systems, including innovations in each part of the information flow process for short-term or dynamic information (which changes or updates within a week) as well as for long-term or static information (which is valid for more than a week). We discuss our phased approach to these innovations, in which modifications were made in small increments and the lessons learned at each step were incorporated into subsequent modifications. We analyze some mistakes and present lessons learned from our experience.

This thesis presents an approach to modelling dynamic mass capture which is applied to a number of system models. The models range from a simple 2D Euler-Bernoulli beam with point masses for the end-effector and target to a 3D Timoshenko beam model (including torsion) with rigid bodies for the end-effector and target. In addition, new models for torsion, as well as software to derive the finite element equations from first principles were developed to support the modelling. Results of the models are compared to a simple experiment as done by Ben Rhody. Investigations of offset capture are done by simulation to show why one would consider using a 3D model that includes torsion. These problems have relevance to both terrestrial robots and to space based robotic systems such as the manipulators on the International Space Station capturing payloads such as the SpaceX Dragon capsule. One could increase production in an industrial environment if industrial robots could pick up items without having to establish a zero relative velocity between the end effector and the item. To have a robot acquire its payload in this way would introduce system dynamics that could lead to the necessity of modelling a previously ‘rigid’ robot as flexible.