Fuel Consumption Minimization Procedure of Sail-assisted Motor Vessel based on a Systematic Meshing of the Explored Area

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Multi-Objective Optimization of Motor Vessel Route

International audienceThis paper presents an original method that allows computation of the optimal route of a motor vessel by minimizing its fuel consumption. The proposed method is based on a new and efficient meshing procedure that is used to define a set of possible routes. A consumption prediction tool has been developed in order to estimate the fuel consumption along a given trajectory. The consumption model involves the effects of the meteorological conditions, the shape of the hull and the power train characteristics. Pareto-optimization with a Multi-Objective Genetic Algorithm (MOGA) is taken as a framework for the definition and the solution of the multi-objective optimization problem addressed. The final goal of this study is to provide a decision helping tool giving the route that minimizes the fuel consumption in a limited or optimum time

Analytical study of coupling between subsystems of a vehicule NVH model

International audienceThe design of an automotive powertrain mounting system plays an important role in improving vehicle noise, vibration and harshness (NVH). One of the main problems encountered in the automotive design remains the isolation of the low frequencies vibrations of the engine from the rest of the vehicle. Several engine mounting schemes have been developed to deal with this problem. Most of these strategies stem from arranging the rigid body modes of the engine mounted on resilient supports to have certain coupled or decoupled characteristics. It is currently admitted in literature that a decoupled powertrain mounting system improves NVH characteristics. The significant engine mass makes the right frequencies and modes arrangement a critical design decision. But it can not be stated that decoupling the on-ground rigid body modes of the engine will systematically reduce chassis vibrations. In this paper, a new analytical method is proposed to examine the mechanisms of coupling between the engine and the vehicle body structure. The analytical procedure enable to define the domain of validity of the mounting schemes based on a 6 degreesof- freedom engine model and to assess NVH improvement

New analytical method to evaluate the powerplant and chassis coupling in the improvement vehicle NVH

International audienceThe design of an automotive powerplant mounting system is an essential part in vehicle safety and improving the vehicle noise, vibration and harshness (NVH) characteristics. One of the main problems encountered in the automotive design is isolating low frequency vibrations of the powerplant from the rest of the vehicle. The significant powerplant mass makes the choice of frequency and mode arrangements a critical design decision. Several powerplant mounting schemes have been developed to improve NVH properties concentrating on the positioning and design of resilient supports. However these methods are based on decoupling rigid body modes from a grounded powerplant model which ignores chassis and suspension system interactions. But it cannot be stated that decoupling the grounded rigid body modes of the powerplant will systematically reduce chassis vibrations. In this paper, a new analytical method is proposed to examine the mechanisms of coupling between the powerplant and the vehicle chassis and subsystems. The analytical procedure expands the equation of motion of the vehicle components to such that a domain of boundary conditions used in the 6 degrees-of-freedom powerplant mounting model can be defined. An example of this new procedure is given for improving NVH chassis response at idle speed using the torque roll axis decoupling strategy

Multi-objective robust design optimization of an engine mounting system

International audienceThis paper introduces a new method to support designers to find optimal and robust solutions of engine mounting system. The mounting system design is a compromise between isolation of the vehicle from engine vibration and constraining the motion of the powertrain within vehicle packaging. Based on the classical pendulum mounting system of a front wheel drive vehicle with a transversely four-cylinder engine, this study deals with the definition of a new global engine mounting concept for the NVH (Noise Vibration and Harshness) improvement of the vehicle characteristics at idle speed. The practical application of the numerical optimization is complicated by the fact that engine mounting system is a stochastic system. Its characteristics have a probabilistic nature. Multi-Objective Genetic Algorithm (MOGA), i.e. Pareto-optimization, is taken as the appropriate framework for the definition and the solution of the addressed multi-objective robust optimization problem. An experimental correlation analysis has been conducted on a Pareto-optimal solution to show the model accuracy

Elasto-geometrical modeling and calibration of robot manipulators: Application to machining and forming applications

International audienceThis paper proposes an original elasto-geometrical calibration method to improve the static pose accuracy of industrial robots involved in machining, forming or assembly applications. Two approaches are presented respectively based on an analytical parametric modeling and a Takagi-Sugeno fuzzy inference system. These are described and then discussed. This allows to list the main drawbacks and advantages of each of them with respect to the task and the user requirements. The Fuzzy Logic model is used in a model-based compensation scheme to increase significantly the robot static pose accuracy in a context of incremental forming application. Experimental results show the efficiency of the Fuzzy Logic model while minimizing development and computational resources

A Systematic Procedure for the Elastodynamic Modeling and Identification of Robot Manipulators

International audienceThis paper presents a systematic procedure for the elastodynamic modeling of industrial robots that is applicable to either serial or parallel manipulators. This procedure is based on a 3-D space generalization of the equivalent rigid link system (ERLS) description, the finite-element method (FEM), and the Lagrange principle. It considers flexible links and joints, and leads to generic equations of motion expressed according to the angles of the actuated joints and the independent elastic degrees of freedom. An efficient identification process through modal analysis is detailed, and the description of damping and joint behavior according to the model application is discussed. The method is applied to a 3-D delta-like parallel structure and successfully validated through an experimental impact testing-based modal analysis

On the Design of PAMINSA: A New Class of Parallel Manipulators with High-Load Carrying Capacities

International audience1 This paper deals with the new results concerning the topologically decoupled parallel manipulators called PAMINSA. The conceptual design of these manipulators, in which the copying properties of pantograph linkage are used, allows obtaining a large payload capability. A newly synthesized fully decoupled 3 degrees of freedom manipulator is discussed and a systematic approach for motion generation of input point of each limb is presented. It is shown that the conditions of complete static balancing of limbs are not effective in the case of dynamic mode of operation. This is approved by numerical simulations and experiments

Vibration analysis of cable-driven parallel robots based on the dynamic stiffness matrix method

This paper focuses on the vibration analysis of Cable-Driven Parallel Robots (CDPRs). An oscillating model of CDPRs able to capture the dynamic behavior of the cables is derived using Lagrangian approach in conjunction with the Dynamic Stiffness Matrix method. Then, an original approach to analyze the modal interaction between the local cable modes and the global CDPR modes is presented. To illustrate this approach, numerical investigations and experimental analyses are carried out on a large-dimension 6-DOF suspended CDPR driven by 8 cables

A Process/Machine coupling approach: Application to Robotized Incremental Sheet Forming

International audienceIn this paper, a Process/Machine coupling approach applied to Robotized Incremental Sheet Forming (RISF) is presented. This approach consists in coupling a Finite Element Analysis (FEA) of the process with an elastic modelling of the robot structure to improve the geometrical accuracy of the formed part. The FEA, assuming a rigid machine, is used to evaluate the forces at the interface between the tool and the sheet during the forming stage. These forces are used as input data for the elastic model, to predict and correct the tool path deviations. In order to make the tool path correction more effective, the weight of three numerical and material parameters of the FEA on the predicted forces is investigated. Finally, the proposed method is validated by the comparison of the numerical and experimental tool paths and geometries obtained with or without correction of the tool path