PUMA 560 Trajectory Control Using NSGA-II Technique With Real Valued Operators

In the industry, Multi-objectives problems are a big defy and they are also hard to be conquered by conventional methods. For this reason, heuristic algorithms become an executable choice when facing this kind of problems.The main objective of this work is to investigate the use of the Non-dominated Sorting Genetic Algorithm II (NSGA-II) technique using the real valued recombination and the real valued mutation in the tuning of the computed torque controller gains of a PUMA560 arm manipulator. The NSGA-II algorithm with real valued operators searches for the controller gains so that the six Integral of the Absolute Errors (IAE) in joint space are minimized. The implemented model under MATLAB allows an optimization of the Proportional-Derivative computed torque controller parameters while the cost functions and time are simultaneously minimized.. Moreover, experimental results also show that the real valued recombination and the real valued mutation operators can improve the performance of NSGA-II effectively

Preliminary design of an autonomous underwater vehicle using multi-objective optimization

The aim of this work is to explore the applicability and usability of multi-objective optimization into various aspects of the design of an autonomous underwater vehicle (AUV). First, I begin with an introduction of the systems engineering design process and the background work for the multi-objective optimization process. Furthermore, I investigate and analyze the existing multi-objective optimization methods in decision making. I focus on various design aspects of an AUV such as the hull design, the weight distribution, the propulsion and, especially, the power supply technology. The objectives I used in the model are the minimization of the power needed to propel the vehicle and the maximization of both the weight of the energy section and the total range. Implementation of both the model and the optimization are carried out using Matlab, particularly the global optimization toolbox and the multi-objective genetic algorithm solver, whereas a special case of two objectives is implemented in Excel using Visual Basic and Excel solver. This research also explores the potential for a designer to use goals in the multi-objective optimization as well as approaches that let a designer choose one particular solution once all Pareto optimal solutions are found.http://archive.org/details/preliminarydesig1094541415Outstanding ThesisLieutenant Commander, Hellenic NavyApproved for public release; distribution is unlimited

Optimization of Chiral Separation of Nadolol by Simulated Moving Bed Technology

Simulated Moving Bed (SMB) technology has gained increasing attention as one of the most powerful techniques for chromatographic separations due to its cost-effectiveness and efficiency. Application of SMB technology is especially important in the pharmaceutical industry for production of enantiopure drugs, as required under strict FDA regulations, to avoid possible adverse effects of racemic drugs. In this study, the performance of the SMB process in separation of racemic nadolol on a perphenyl carbamoylated beta cyclodextrin (β-CD) stationary phase was investigated. The equilibrium dispersive model coupled with bi-Langmuir adsorption isotherm and lumped kinetic approximation, constitute the mathematical model used to simulate the dynamic behavior of SMB. Multi-objective optimization was carried out using a robust state-of-the-art optimization technique, non-dominated sorting genetic algorithm (NSGA). Two optimization problems were solved to simultaneously maximize productivity and purity of the product and minimize consumption of desorbent. The generated Pareto optimal solutions showed that selection of operating conditions can significantly affects the performance of SMB to meet the desired objectives

Hybrid Electromagnetic Vibration Isolation Systems

Traditionally, dynamic systems are equipped with passive technologies like viscous shock absorbers and rubber vibration isolators to attenuate disturbances. Passive elements are cost effective, simple to manufacture, and have a long life span. However, the dynamic characteristics of passive devices are fixed and tuned for a set of inputs or system conditions. Thus in many applications when variation of input or system conditions is present, sub-optimal performance is realized. The other fundamental flaw associated with passive devices is that they expel the undesired kinetic energy as heat. Recently, the introduction of electromagnetic technologies to the vibration isolation systems has provided researchers with new opportunities for realizing active/semi-active vibration isolation systems with the additional benefit of energy regeneration (in semi-active mode). Electromagnetic vibration isolators are often suffer from a couple of shortcomings that precludes their implementations in many applications. Examples of these short comings include bulky designs, low force density, high energy consumption (in active mode), and fail-safe operation problem. This PhD research aims at developing optimal hybrid-electromagnetic vibration isolation systems to provide active/semi-active and regenerative vibration isolation for various applications. The idea is to overcome the aforementioned shortcomings by integrating electromagnetic actuators, conventional damping technologies, and stiffness elements into single hybrid packages. In this research, for both semi-active and active cases, hybrid electromagnetic solutions are proposed. In the first step of this study, the concept of semi-active hybrid damper is proposed and experimentally tested that is composed of a passive hydraulic and a semi-active electromagnetic components. The hydraulic medium provides a bias and fail-safe damping force while the electromagnetic component adds adaptability and energy regeneration to the hybrid design. Based on the modeling and optimization studies, presented in this work, an extended analysis of the electromagnetic damping component of the hybrid damper is presented which can serve as potent tool for the designers who seek maximizing the adaptability (and regeneration capacity) of the hybrid damper. The experimental results (from the optimized design) show that the damper is able to produce damping coefficients of 1300 and 0-238 Ns/m through the viscous and electromagnetic components, respectively. In particular, the concept of hybrid damping for the application of vehicle suspension system is studied. It is shown that the whole suspension system can be adjusted such that the implementation of the hybrid damper, not only would not add any adverse effects to the main functionally of the suspension, but it would also provide a better dynamics, and enhance the vehicle fuel consumption (by regenerating a portion of wasted vibration energy). In the second step, the hybrid damper concept is extended to an active hybrid electromagnetic vibration isolation systems. To achieve this target, a passive pneumatic spring is fused together with an active electromagnetic actuator in a single hybrid package. The active electromagnetic component maintains a base line stiffness and support for the system, and also provides active vibration for a wide frequency range. The passive pneumatic spring makes the system fail-safe, increases the stiffness and support of the system for larger masses and dead loads, and further guarantees a very low transmissibility at high frequencies. The FEM and experimental results confirmed the high force density of the proposed electromagnetic component, comparing to a voice coil of similar size. In the proposed design, with a diameter of ~125 mm and a height of ~60 mm, a force variation of ~318 N is obtained for the currents of I=±2 A. Furthermore, it is demonstrated that the proposed actuator has a small time constant (ratio of inductance to resistance for the coils) of less than 5.2 ms, with negligible eddy current effect, making the vibration isolator suitable for wide bandwidth applications. According to the results, the active controllers are able to enhance the performance of the passive elements by up to 80% and 95% in terms of acceleration and force transmissibilities, respectively

Front underride protection devices: design methodology for heavy vehicle crashworthiness

North American Heavy Vehicles contribute to a third of all road fatalities in Canada. Head on collisions are one of the most severe, as the mismatch of vehicle weight and sizing intensifies when a passenger vehicle is impacted. To improve crash safety, Front Underride Protection Devices (FUPDs) are a proposed solution to establishing a compatible collision between a passenger vehicle and a heavy vehicle. The European Union is among numerous administrations to regulate FUPDs, yet FUPDs are nonexistent in North America. Current regulations conform to European Cab-over Engine Tractors designs. Implementation of current regulations in North American conflicts with the widely driven Conventional Style Tractor due to the different design space for a FUPDs. This study builds on developing regulations for North America, and establishes a design methodology to developing and optimizing FUPDs for the Conventional Style Tractor enlightening the crashworthy importance of front underride protection devices to improving road safety. Advanced two stage optimization methodology was outlined to ensure industry targets are embedded with in the design to develop lightweight and cost effective devices. Recommendations for the modifications of the ECE R93 for Conventional Style Tractor are outlined; P1 load magnitudes requirements for FUPD stiffness should be increased from the regulated 80 kN to 160 kN to improve small overlap collisions. Regulated geometric parameters were recommended to have a minimal frontal contact height of 240mm, with ground clearance set between 350mm to 400mm. Geometric configurations were outlined and restricted to conform to the aerodynamic curvatures of the tractors bumper. After validation of the National Crash Analysis Center (NCAC) Toyota Yaris finite element analysis (FEA) model for side impact, the addition of a FUPD enhanced the survivability of passenger vehicle. The work achieved in enhancing the design methodology for industrial implementation and outlining regulations for North America

Application d’algorithmes génétiques multi-objectifs et études expérimentales de la durée de vie du faisceau de l’anneau de stockage du synchrotron SOLEIL

This thesis is dedicated to the optimization of the nonlinear beam dynamics of synchrotron radiation light sources using Multi-objective Genetic Algorithms (MOGA-ELEGANT). In the first part the ELEGANT code is benchmarked against TRACY3; then MOGA is tuned and used to find the best settings of quadrupole and sextupole magnets in order to maximize the dynamic and momentum apertures, strongly related with the Touschek lifetime and the injection efficiency respectively. Solutions obtained after one month of computation in the high level computational cluster of SOLEIL using 200 CPUs are analyzed. The improvement of the Touschek lifetime obtained with MOGA is confirmed by the beam-based experiments. The beam lifetime of the SOLEIL storage ring is increased 50-60 % .The second part this PhD work is devoted to study experimentally the beam lifetime of the SOLEIL storage ring to improve the understanding of the beam lifetime and its contributions: the Touschek and gas lifetimes. The beam lifetime is measured in function of important parameters as coupling, horizontal and vertical scrapers, and bunch current. The experimental results are compared with the simulated ones. The Piwinski formula is implemented in the tracking code TRACY3 to replace Bruck approximation. The gas lifetimes were computed using analytical models. This study allows understanding that the composition of the residual gas and the local pressure along all the machine vary significantly between the arcs and the in-vacuum insertion devices: new effective atomic number are obtained. This type of measurement remains difficult to analyze without a large error margin; in-vacuum insertions have a dominant contribution. The shape of the experimental curves is closed to the expected ones and compatible with an effective atomic number of about 7.Cette thèse est consacrée à l’optimisation des sources de lumière synchrotron. La dynamique de faisceau non linéaire de l'anneau de stockage du synchrotron SOLEIL est optimisée à l’aide d’algorithmes génétiques multiobjectifs (MOGA-ELEGANT). Le code ELEGANT est d’abord comparé avec le code étalon de SOLEIL, TRACY3. Le code MOGA est ensuite utilisé pour obtenir les meilleures configurations possible en termes d’ouvertures dynamiques et d’acceptances en énergie, qui sont fortement en rapport avec la durée de vie Touschek et l'efficacité d'injection respecti-vement. Après 1 mois de calcul sur le cluster de calcul de haute performance de SOLEIL en utilisant 200 CPU, un ensemble de solutions est trouvé. Elles sont testées expérimentalement dans la salle de contrôle du SOLEIL. L'amélioration de la durée de vie Touschek obtenue est confirmée par les mesures : la durée de vie du faisceau de l'anneau de stockage de SOLEIL est accrue de 50 à 60%.La deuxième partie de ce travail de thèse présente une étude expérimentale de la durée de vie du faisceau de l'anneau de stockage de SOLEIL. En particulier les contributions de la durée de vie Touschek et la durée de vie de gaz sont étudiées. La durée de vie du faisceau est mesurée en fonction de paramètres importants tels que le couplage, racleurs horizontaux et verticaux, et le courant. Les résultats expérimentaux sont comparés avec les durées de vie Touschek calculées par la formule Piwinski mise en œuvre dans le code TRACY3 et la durée de vie du gaz calculée analytiquement. Cette étude permet de montrer que la composition du gaz résiduel et la pression locale varient de manière importante le long de toute la machine: l’effet des ondulateurs sous-vide est dominant. Des nombres atomiques effectifs sont obtenus. La forme des courbes expérimentales est proche des courbes simulées et est compatible avec un nombre atomique effectif proche de 7