Search results for "Position"

A new approach to simulate coating thickness in cold spray

2020

Abstract In the process of cold spray on complex components, the coating thickness is an important indicator to monitor and control. Current methods such as destructive tests or direct mechanical measurements can only be performed after spraying. Besides, these methods lead to production shutdown and additional costs . This article presents a novel approach predicting coating thickness for components with complex curved surfaces, especially in the case of shadow effects. Firstly, a three-dimensional geometric model of the coating profile based on Gaussian distribution was developed. In addition, the relative deposition efficiency (RDE) resulting from the different robot kinematic parameters…

Surface Characteristics of Machined Polystyrene with 3D Printed Thermoplastic Tool

2020

An effort is made in this work to appraise the surface characteristics of machined expandable polystyrene (EPS) with a novel 3D printed thermoplastic acrylonitrile-butadiene-styrene (ABS) tool. Linear grooves on EPS were made on a vertical milling machine that was modified to conduct experiments in the laboratory. The tests were designed as per the Taguchi L9 based factorial design of experimentation while varying process parameters such as depth of cut, spindle speed, and feed rate. The machining responses dimensional accuracy and surface roughness of the machined grooves were studied. Furthermore, the surface topography of the machined specimens was considered to investigate the mechanism…

A decomposition approach to dual shuttle automated storage and retrieval systems

2016

[EN] Automated Storage and Retrieval Systems (AS/RS) have become vital in today¿s distribution and production environments, however it remains necessary to equip them with more efficient operational control policies. Motivated by real situations encountered by companies employing AS/RS, the present paper studies a miniload AS/RS system, with a dual shuttle crane in which a set of storage and retrieval requests must be scheduled such that the prioritized waiting time is minimized. Dual shuttle cranes have received minimal academic attention and thus continue to pose new problems that must be solved. The miniload AS/RS problem is addressed by decomposing it into a location assignment and sequ…

Interrogating witnesses for geometric constraint solving

2012

International audience; Classically, geometric constraint solvers use graph-based methods to decompose systems of geometric constraints. These methods have intrinsic limitations, which the witness method overcomes; a witness is a solution of a variant of the system. This paper details the computation of a basis of the vector space of free infinitesimal motions of a typical witness, and explains how to use this basis to interrogate the witness for dependence detection. The paper shows that the witness method detects all kinds of dependences: structural dependences already detectable by graph-based methods, but also non-structural dependences, due to known or unknown geometric theorems, which…

Decomposition and Mean-Field Approach to Mixed Integer Optimal Compensation Problems

2016

Mixed integer optimal compensation deals with optimization problems with integer- and real-valued control variables to compensate disturbances in dynamic systems. The mixed integer nature of controls could lead to intractability in problems of large dimensions. To address this challenge, we introduce a decomposition method which turns the original n-dimensional optimization problem into n independent scalar problems of lot sizing form. Each of these problems can be viewed as a two-player zero-sum game, which introduces some element of conservatism. Each scalar problem is then reformulated as a shortest path one and solved through linear programming over a receding horizon, a step that mirro…

Microstructural, mechanical and energy demand characterization of alternative WAAM techniques for Al-alloy parts production

2020

Abstract Additive manufacturing (AM) processes are gathering momentum as an alternative to conventional manufacturing processes. A research effort is being made worldwide to identify the most promising AM approaches. Within this category, wire arc additive manufacturing (WAAM) is among the most interesting, especially when large parts must be manufactured. In this paper, two different WAAM deposition techniques suitable for the deposition of Aluminum alloys, Cold Metal Transfer (CMT) and CMT mix drive, are analyzed and compared. With the aim of obtaining a clear picture concerning the two different techniques, microstructural analyses, mechanical property evaluation and electrical energy de…

Analysis of Linear Feedback Position Control in Presence of Presliding Friction

2016

Emotional Design: Discovering Emotions Across Cars’ Morphologies

2020

The primary focus behind the overall design involves shifting from a designer-centric concept to a user-centric one. In essence, cars are utilitarian from an engineering point of view and symbolic-emotional from a social point of view. The modern car retains a strong social position and also generates vivid emotions. The tellability of a car is the priority when communicating with a customer. As a result, this paper proposes a computational approach towards studying the relationship between car morphology and the aforementioned produced emotions. Emotions are considered self-measurable and physiologically distinct. Each car is thus self-evaluated emotionally by a panel of potential users. T…

Location-Aware MAC Scheduling in Industrial-Like Environment

2018

We consider an environment strongly affected by the presence of metallic objects, that can be considered representative of an indoor industrial environment with metal obstacles. This scenario is a very harsh environment where radio communication has notorious difficulties, as metallic objects create a strong blockage component and surfaces are highly reflective. In this environment, we investigate how to dynamically allocate MAC resources in time to static and mobile users based on context awareness extracted from a legacy WiFi positioning system. In order to address this problem, we integrate our WiFi ranging and positioning system in the WiSHFUL architecture and then define a hypothesis t…

Simple Large Scale 3D scanner

2019

Abstract A new 3D measuring device for large dimensions is proposed. It is based on the combination of a simple system consisting of a smartphone that measures in stereo a near field with a robotic total station that tracks the position of the camera on a far field. The calibration method is described and the metrological properties obtained make it possible to measure objects of several tens or even hundreds of meters long with errors of the order of a millimeter. This makes it possible to consider the use of the system for many industrial applications