A sensorless virtual slave control scheme for kinematically dissimilar master-slave teleoperation

The use of telerobotic systems is essential for remote handling (RH) operations in radioactive areas of scientific facilities that generate high doses of radiation. Recent developments in remote handling technology has seen a great deal of effort being directed towards the design of modular remote handling control rooms equipped with a standard master arm which will be used to separately control a range of different slave devices. This application thus requires a kinematically dissimilar master-slave control scheme. In order to avoid drag and other effects such as friction or other non-linear and unmodelled slave arm effects of the common position-position architecture in nonbackdrivable slaves, this research has implemented a force-position control scheme. End-effector force is derived from motor torque values which, to avoid the use of radiation intolerant and costly sensing devices, are inferred from motor current measurement. This has been demonstrated on a 1-DOF test-rig with a permanent magnet synchronous motor teleoperated by a Sensable Phantom Omni® haptic master. This has been shown to allow accurate control while realistically conveying dynamic force information back to the operator

bilateral robot therapy based on haptics and reinforcement learning feasibility study of a new concept for treatment of patients after stroke

n/

Autonomous landing of fixed-wing aircraft on mobile platforms

E n esta tesis se propone un nuevo sistema que permite la operación de aeronaves autónomas sin tren de aterrizaje. El trabajo está motivado por el interés industrial en aeronaves con la capacidad de volar a gran altitud, con más capacidad de carga útil y capaces de aterrizar con viento cruzado. El enfoque seguido en este trabajo consiste en eliminar el sistema de aterrizaje de una aeronave de ala fija empleando una plataforma móvil de aterrizaje en tierra. La aeronave y la plataforma deben sincronizar su movimiento antes del aterrizaje, lo que se logra mediante la estimación del estado relativo entre ambas y el control cooperativo del movimiento. El objetivo principal de esta Tesis es el desarrollo de una solución práctica para el aterrizaje autónomo de una aeronave de ala fija en una plataforma móvil. En la tesis se combinan nuevos métodos con experimentos prácticos para los cuales se ha desarrollado un sistema de pruebas específico. Se desarrollan dos variantes diferentes del sistema de aterrizaje. El primero presta atención especial a la seguridad, es robusto ante retrasos en la comunicación entre vehículos y cumple procedimientos habituales de aterrizaje, al tiempo que reduce la complejidad del sistema. En el segundo se utilizan trayectorias optimizadas del vehículo y sincronización bilateral de posición para maximizar el rendimiento del aterrizaje en términos de requerimientos de longitud necesaria de pista, pero la estabilidad es dependiente del retraso de tiempo, con lo cual es necesario desarrollar un controlador estabilizador ampliado, basado en pasividad, que permite resolver este problema. Ambas estrategias imponen requisitos funcionales a los controladores de cada uno de los vehículos, lo que implica la capacidad de controlar el movimiento longitudinal sin afectar el control lateral o vertical, y viceversa. El control de vuelo basado en energía se utiliza para proporcionar dicha funcionalidad a la aeronave. Los sistemas de aterrizaje desarrollados se han analizado en simulación estableciéndose los límites de rendimiento mediante múltiples repeticiones aleatorias. Se llegó a la conclusión de que el controlador basado en seguridad proporciona un rendimiento de aterrizaje satisfactorio al tiempo que suministra una mayor seguridad operativa y un menor esfuerzo de implementación y certificación. El controlador basado en el rendimiento es prometedor para aplicaciones con una longitud de pista limitada. Se descubrió que los beneficios del controlador basado en el rendimiento son menos pronunciados para una dinámica de vehículos terrestres más lenta. Teniendo en cuenta la dinámica lenta de la configuración del demostrador, se eligió el enfoque basado en la seguridad para los primeros experimentos de aterrizaje. El sistema de aterrizaje se validó en diversas pruebas de aterrizaje exitosas, que, a juicio del autor, son las primeras en el mundo realizadas con aeronaves reales. En última instancia, el concepto propuesto ofrece importantes beneficios y constituye una estrategia prometedora para futuras soluciones de aterrizaje de aeronaves.In this thesis a new landing system is proposed, which allows for the operation of autonomous aircraft without landing gear. The work was motivated by the industrial need for more capable high altitude aircraft systems, which typically suffer from low payload capacity and high crosswind landing sensitivity. The approach followed in this work consists in removing the landing gear system from the aircraft and introducing a mobile ground-based landing platform. The vehicles must synchronize their motion prior to landing, which is achieved through relative state estimation and cooperative motion control. The development of a practical solution for the autonomous landing of an aircraft on a moving platform thus constitutes the main goal of this thesis. Therefore, theoretical investigations are combined with real experiments for which a special setup is developed and implemented. Two different landing system variants are developed — the safety-based landing system is robust to inter-vehicle communication delays and adheres to established landing procedures, while reducing system complexity. The performance-based landing system uses optimized vehicle trajectories and bilateral position synchronization to maximize landing performance in terms of used runway, but suffers from time delay-dependent stability. An extended passivity-based stabilizing controller was implemented to cope with this issue. Both strategies impose functional requirements on the individual vehicle controllers, which imply independent controllability of the translational degrees of freedom. Energy-based flight control is utilized to provide such functionality for the aircraft. The developed landing systems are analyzed in simulation and performance bounds are determined by means of repeated random sampling. The safety-based controller was found to provide satisfactory landing performance while providing higher operational safety, and lower implementation and certification effort. The performance-based controller is promising for applications with limited runway length. The performance benefits were found to be less pronounced for slower ground vehicle dynamics. Given the slow dynamics of the demonstrator setup, the safety-based approach was chosen for first landing experiments. The landing system was validated in a number of successful landing trials, which to the author’s best knowledge was the first time such technology was demonstrated on the given scale, worldwide. Ultimately, the proposed concept offers decisive benefits and constitutes a promising strategy for future aircraft landing solutions

Design and Development of a Bilateral Therapeutic Hand Device for Stroke Rehabilitation

The major cause of disability is stroke. It is the second highest cause of death after coronary heart disease in Australia. In this paper, a post stroke therapeutic device has been designed and developed for hand motor function rehabilitation that a str

The acute effects of different blood flow restriction settings on blood lactate, electromyography and leg strength during bilateral knee extensions

The current protocols being used for Blood Flow Restriction (BFR) exercise did not examine the effects of different Initial Restrictive Pressures (pressure applied to limb by cuff prior to inflation, IRP) during design. There are several research articles highlighting the importance of IRP and how it can create variability in results. Therefore it is necessary to evaluate the current BFR protocol against different IRP in order to determine reliability. PURPOSE: The purpose of this study was to examine the acute effects of different blood flow restriction setting on 1) the level of blood lactate production, 2) neuromuscular activation (the changes in motor unit activation and median frequency), and 3) fatigue response during bilateral knee extension exercise. METHODS: Thirty-three male (age= 26.63 (5.8), n=17) and female (age= 22.76 (3.3), n=16) participants performed four sets of bilateral knee extensions on four separate occasions separated by at least 48 hours. Each session was randomized into the following conditions: IRP50@FRP+20, IRP65@FRP-20, IRP50 (Control), and IRP65. During each condition, blood pressure (BP), heart rate (HR), rate of perceived exertion (RPE), discomfort/pain (DF), and blood lactate were recorded throughout the study. Maximal voluntary contraction (MVC) was recorded pre and post exercise. Electromyography was recorded at the vastus lateralis and rectus femoris with a focus on motor unit activation (RMS) and muscle firing rate (MDF). RESULTS: No significant difference was found between conditions for BP, blood lactate or RPE. HR displayed a condition*gender interaction (p=0.022) and a trend for a condition*time interaction (p\u3c0.06). IRP65@FRP-20 displayed a trend for increased levels of DF (p=0.062); it also produced significantly higher decreases in pre to post MVC in both males and females (p\u3c0.023), showing a strong trend for a greater effect in males (p=0.055). IRP65@FRP-20 further displayed greater levels of overall motor recruitment in the vastus lateralis (p=0.024) as well as greater levels of motor recruitment throughout sets 2-4 in the vastus lateralis (p\u3c0.01) and rectus femoris (p\u3c0.01). CONCLUSION:IRP65@FRP-20 created greater variations amongst the variables compared to the Control, despite having a lower final restrictive pressure. This suggests that the current protocol may not be the most reliable method of BFR. Further research is needed to develop a protocol that takes IRP into account

Performance evaluation of a six-axis generalized force-reflecting teleoperator

Work in real-time distributed computation and control has culminated in a prototype force-reflecting telemanipulation system having a dissimilar master (cable-driven, force-reflecting hand controller) and a slave (PUMA 560 robot with custom controller), an extremely high sampling rate (1000 Hz), and a low loop computation delay (5 msec). In a series of experiments with this system and five trained test operators covering over 100 hours of teleoperation, performance was measured in a series of generic and application-driven tasks with and without force feedback, and with control shared between teleoperation and local sensor referenced control. Measurements defining task performance included 100-Hz recording of six-axis force/torque information from the slave manipulator wrist, task completion time, and visual observation of predefined task errors. The task consisted of high precision peg-in-hole insertion, electrical connectors, velcro attach-de-attach, and a twist-lock multi-pin connector. Each task was repeated three times under several operating conditions: normal bilateral telemanipulation, forward position control without force feedback, and shared control. In shared control, orientation was locally servo controlled to comply with applied torques, while translation was under operator control. All performance measures improved as capability was added along a spectrum of capabilities ranging from pure position control through force-reflecting teleoperation and shared control. Performance was optimal for the bare-handed operator

P-8 and the Trilateral Partnership. The operational significance and influence on Norwegian security policy

The background for and the strategic context of this thesis is the threat posed by Russian submarines to Norway and NATO in the North Atlantic. In light of this, the study examines the significance of the P-8 and the trilateral partnership of Norway, the United Kingdom and the United States, by asking two research questions: - What is the operational significance of the P-8 and the trilateral partnership? - How does the P-8 and the trilateral partnership influence Norwegian security policy? It is an explorative and inductive study, which answers the research questions through a qualitative analysis. The thesis uses deterrence, crisis stability and maritime airpower theory, as well as Norwegian Security policy and defence concept, with emphasis on integration and reassurance to frame the discussion. The thesis concludes that the P-8 will provide Norwegian decision-makers with an agile platform with significantly improved capability for ASW and ISR. The trilateral partnership integrates the three partner nations and improves NATOs ASW capability when facing Russian submarines in the North Atlantic. The P-8 and the partnership influence deterrence positively by integrating Norway, NATO and the US, and provide tools for improving crisis stability. However, given the impermanency of American Poseidons, there is a need to establish a trilateral P-8 concept that merges training, exorcises and operations as a signal of presence and integration in the North Atlantic. The contribution of the P-8 in Norway’s policy of reassuring Russia is important as Norway increasingly develops a force structure with so-called offensive strategic capabilities. Of particular importance to reassurance is enhancements in intelligence contributions. Provided the strategic context, improved capabilities and the Norwegian force structure, the influence of the P-8 is decisive for the Norwegian security policy.Bakgrunnen for denne oppgaven og den strategiske konteksten er trusselen Russiske ubåter utgjør for Norge og NATO i Nord-Atlanteren. I lys av dette undersøker oppgaven betydningen av P-8 og trilateralt samarbeidet mellom Norge, Storbritannia og USA, gjennom å stille to forskningsspørsmål: - Hva er den operative betydningen av P-8 og det trilaterale partnerskapet? - Hvordan påvirker P-8 og det trilaterale partnerskapet norsk sikkerhetspolitikk? Studien er eksplorativ og induktiv, og benytter kvalitativ metode for å besvare forskningsspørsmålene. Analysen nyttiggjør teorier for avskrekking, krisestabilitet og maritim luftmakt, i tillegg til norsk sikkerhetspolitikk med vekt på integrasjon og beroligelse, som rammeverk for diskusjonen. Oppgaven konkluderer med at P-8 vil tilføre norske beslutningstakere en fleksibel plattform som i betydelig grad bedrer evnen til anti-ubåt krigføring (ASW) og informasjonsinnhenting (ISR). Det trilaterale samarbeidet integrerer de tre partnernasjonene og bedrer NATOs evne til ASW i møte med russiske ubåter. P-8 og det trilaterale partnerskapet påvirker avskrekking positivt gjennom integrering av Norge, NATO og USA, og tilbyr muligheter for å bedre krisestabiliteten. På en annen side er det forventet at amerikansk tilstedeværelse med P-8 vil være av en mindre permanent karakter. Dette medfører et behov for et trilateralt P-8 konsept som sammenslår trening, øvelser og operasjoner i Nord-Atlanteren. P-8s bidrag innen beroligelse er av sentral karakter, ettersom Norge i økende grad satser på avskrekkende kapabiliteter i styrkestrukturen. Spesielt viktig er økt kapasitet innen etterretningsbidragene. Med utgangspunkt i den strategiske konteksten, forbedrede kapabiliteter og den norske styrkestrukturen, er innflytelsen til maritime patruljefly av avgjørende betydning for norsk sikkerhetspolitik

Biomechanical Comparison of Old and New Cheer Shoes in Collegiate Cheerleaders

INTRODUCTION: The sport of cheerleading requires that athletes perform with a high degree of flexibility, strength, endurance, and balance. The leading injury in cheerleading is a lateral, inversion, ankle sprain. As footwear serves as an interface between the foot and the surrounding environment, characteristics of shoes should be monitored to determine the effects on proprioceptive communication. No previous literature was found that examined the biomechanical differences between “Old” and “New” shoes in collegiate cheerleaders. PURPOSE: The purpose of this study was to examine the biomechanical differences exhibited by collegiate cheerleaders while performing balance testing and step-down, landing tasks in “old” and “new” cheer shoes. METHODS: Participants included 5 male and 20 female collegiate cheerleaders (19.88 ± 1.36 years; 61.94 ± 9.33 kg; 162.70 ± 6.68 cm). Sixteen anatomical retroreflective markers were placed on each participants’ lower extremities. Participants completed randomized trials of ten balance conditions as well as step-down tasks consisting of a leveled and a tilted platform. Data collected from two days of testing was used for analysis. RESULTS: Analyses revealed no statistical significance for postural sway measures between “Old” and “New” shoes (p\u3e.05). Analyses revealed a statistically significant interaction between shoe and condition when examining the ankle joint angle during step-down tasks (F(1,24)=12.070, p=.002). Further investigation revealed main effects of both shoe (F(1,24)=85.541,