Shape memory alloys (SMA) are often used as actuators in miniature articulated devices. In this paper, a single TiNi SMA wire loaded by a mass is studied as a basic actuator controlled by Joule's effect. First, we describe an experimental study of the wire (150,m in diameter) under coupled stress and temperature actions for different thermal input velocities in order to analyze its dynamical behavior. In the case of static loadings, modeling is performed with a macroscopic description of the thermomechanical behavior preformed by Leclercq and Lexcellent (1996). Then, the heat equation integration is sufficient to take into account the thermal input velocities. Comparison between experiment and modeling is fairly correct.
A method allowing a systematic generation of assembly plans for mechanical products is presented. It involves a product modelling that includes non-assembly relevant features like labelling, checking, etc. Assembly plans are represented by assembly trees and are produced through interactive software written in PROLOG. An analysis of assembly constraints is also presented with a distinction between operative constraints dealing with the feasibility of the operations involved in the different assembly plans and the strategic constraints dealing with the global structure of the plans. An automatic transformation of the resulting assembly plans into one or several precedence graphs is given as well as a generalization of the classic precedence graphs in precedence hypergraphs able to represent disjunctive precedence conditions.
This paper proposes a modeling method of these control laws for manufacturing system. The robustness for these categories of system is discussed. Our approach consists in managing the disturbances of the drifts type of quality of the product. The Intervals Constrained Petri Net (ICPN) are used for the modeling of the no temporal constraints. A methodology of construction of a robust control system generating the margins of passive and active robustness is elaborated. The redundancy of the robustness of the elementary parameters between passive and active leads us to define the ways ensuring the total robustness of the system.
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