60 research outputs found
Planification de trajectoire et contrôle d'un système collaboratif : Application à un drone trirotor
This thesis is dedicated to the creation of a complete framework, from high-level to low-level, of trajectory generation for a group of independent dynamical systems. This framework, based for the trajectory generation, on the resolution of Burgers equation, is applied to a novel model of trirotor UAV and uses the flatness of the two levels of dynamical systems.The first part of this thesis is dedicated to the generation of trajectories. Formal solutions to the heat equation are created using the differential flatness of this equation. These solutions are transformed into solutions to Burgers' equation through Hopf-Cole transformation to match the desired formations. They are optimized to match specific requirements. Several examples of trajectories are given.The second part is dedicated to the autonomous trajectory tracking by a trirotor UAV. This UAV is totally actuated and a nonlinear closed-loop controller is suggested. This controller is tested on the ground and in flight by tracking, rolling or flying, a trajectory. A model is presented and a control approach is suggested to transport a pendulum load.L'objet de cette thèse est de proposer un cadre complet, du haut niveau au bas niveau, de génération de trajectoires pour un groupe de systèmes dynamiques indépendants. Ce cadre, basé sur la résolution de l'équation de Burgers pour la génération de trajectoires, est appliqué à un modèle original de drone trirotor et utilise la platitude des deux systèmes différentiels considérés. La première partie du manuscrit est consacrée à la génération de trajectoires. Celle-ci est effectuée en créant formellement, par le biais de la platitude du système considéré, des solutions à l'équation de la chaleur. Ces solutions sont transformées en solution de l'équation de Burgers par la transformation de Hopf-Cole pour correspondre aux formations voulues. Elles sont optimisées pour répondre à des contraintes spécifiques. Plusieurs exemples de trajectoires sont donnés.La deuxième partie est consacrée au suivi autonome de trajectoire par un drone trirotor. Ce drone est totalement actionné et un contrôleur en boucle fermée non-linéaire est proposé. Celui-ci est testé en suivant, en roulant, des trajectoires au sol et en vol. Un modèle est présenté et une démarche pour le contrôle est proposée pour transporter une charge pendulaire
Validation of an LC-MS/MS Method Using Solid-Phase Extraction for the Quantification of 1-84 Parathyroid Hormone: Toward a Candidate Reference Measurement Procedure.
peer reviewed[en] BACKGROUND: Parathyroid hormone (PTH) measurement is important for patients with disorders of calcium metabolism, including those needing bone-turnover monitoring due to chronic kidney disease-mineral bone disorder. There are currently 2 generations of PTH immunoassays on the market, both having cross-reactivity issues and lacking standardization. Therefore, we developed an LC-MS/MS higher-order method for PTH analysis.
METHODS: The method was calibrated against the international standard for 1-84 PTH (WHO 95/646). Antibody-free sample preparation with the addition of an isotope-labeled internal standard was performed by solid-phase extraction. Extracts were analyzed by LC-MS/MS. EDTA-K2 plasma was used throughout the development and validation. Bias and uncertainty sources were tested according to ISO 15193. Clinical Laboratory Standards Institute guidelines and reference measurement procedures were consulted for the design of the validation. Patient samples and external quality controls were compared between LC-MS/MS and 2 third-generation immunoassays.
RESULTS: The method was validated for 1-84 PTH from 5.7 to 872.6 pg/mL. The interassay imprecision was between 1.2% and 3.9%, and the accuracy ranged from 96.2% to 103.2%. The measurement uncertainty was <5.6%. The comparison between LC-MS/MS and the immunoassays showed a proportional bias but moderate to substantial correlation between methods.
CONCLUSIONS: This LC-MS/MS method, which is independent of antibodies, is suitable for a wide range of PTH concentrations. The obtained analytical performance specifications demonstrate that development of a reference measurement procedure will be possible once a higher order reference standard is available
Motion Planning for Multi-Agent Systems Using Gevrey Trajectories Based on Burgers' Viscous Equation
International audienceThe differential flatness of the one-dimensional heat equation controlled at each boundary is used to propose, through the Hopf-Cole transform, a finite-time motion planning for multi-agent systems. The proposed paths, which are solutions of Burgers' viscous equation, are smooth while non analytical in initial and final equilibria. The paths may respect various geometrical constraints allowing them to be used for different purposes
Ground Control of a Hybrid Tricopter
International audienceOptimizing energy consumption of Micro Aerial Vehicles is one of several problems that remains to be solved in the domain of UAVs. In a recent work, a novel quadrotor was introduced that was able, when possible, to roll on the ground thanks to a tilting propeller and caster wheels. In the following work, we build upon this idea with a trirotor helicopter where all the rotors are independently tilting. This grants our model a greater maneuverability both in flight and on the ground. We validate in this paper the flatness-based control approach by showing the ability of our UAV to follow arbitrary trajectories on the ground
Trajectory tracking of Trirotor UAV with Pendulum Load
International audienceRecently increasing attention has been paid to multirotor small-scale autonomous helicopters. The most studied rotor layout is the so-called quadrotor helicopter, also called quadcopter. However, these UAVs can be seen as lacking agility as they cannot move in their horizontal plane and thus have to rotate to perform translations. In this work, we develop on a layout involving only three rotors with tilting capabilities. We show in the following the advantage of this layout for tracking arbitrary trajectories and for transporting a pendulum load
Multi-Agent Motion Planning Using Burgers' Viscous Equation and Hopf-Cole Transformation, A Flatness-based implementation
International audienceIn a previous work, we showed how the flatness of the heat equation with two controls at both ends of the domain could be used to generate solutions to create solutions to Burgers' equation. The created solutions were thought as a motion planner for a multi-agent systems of e.g. ground robots, UAVs. The trajectories of the different particles of the PDE are to be used as input for a feed-forward control. In this paper, we show a practical implementation of this method, oriented toward computational efficiency based on Particles Swarm Optimization. In a first section we introduce the flatness based mathematical framework of our planner. We present the implementation in a second part. We present examples of trajectories in a last section and study and discuss the performances and the properties of the generated trajectories before drawing conclusions and future use of the framework in real UAVs systems
Motion Planning for Multi-Agent Systems Using Gevrey Trajectories Based on Burgers' Viscous Equation
International audienceThe differential flatness of the one-dimensional heat equation controlled at each boundary is used to propose, through the Hopf-Cole transform, a finite-time motion planning for multi-agent systems. The proposed paths, which are solutions of Burgers' viscous equation, are smooth while non analytical in initial and final equilibria. The paths may respect various geometrical constraints allowing them to be used for different purposes
- …