Pierre Couturier

An Artificial Intelligence approach for the multicriteria optimization in mechatronic products design

This study is related to the integration of Artificial Intelligence approaches in the optimization of mechatronic products design. The purpose is to help designers to choose design parameters according to technical specifications and customers needs. Because of the high number of parameters and possible combinations, a heuristic based approach is investigated for optimization activity when the task is a multiple objective combinatorial one and when the criteria to be optimized cannot be weighted or ordered. A Hybrid Search (HS) algorithm based on some metaheuristic mechanisms is proposed for optimization without resuming the multiple objectives to a single one. The specified algorithm derives the best (not dominated) solution set: the Pareto front, from the set of acceptable solutions defined by the design parameters, and is quite faster compared to exhaustive methods. Self-organizing Maps are then used to analyze the obtained fronts. Our approach is fully illustrated in the case of the design of a 2-Degrees Of Freedom robot.

Needs for Tracing the Consequences of Decisions in Mechatronics Design

As the design of mechatronic systems relies on different technical and scientific disciplines, it is often difficult to anticipate, at the earliest, the consequences of design choices on the final product. The role of the evaluation process is to support designers each time engineering choices must be made or justified. Being able to estimate the impact of design decisions on key technical performance indicators is one objective of our research. After having presented the activities of the evaluation process, we propose a meta-model of the data required by evaluation in the context of the Systems Engineering framework. Then we investigate how the top down and bottom up tracing of technical requirements through Block Systems and between systems engineering layers of the ‘onion model’ may help designers analyze the consequences of design decisions on the final product. The research is illustrated through the development of a wheelchair with electrical assistance so as to allow reduced mobility people to move and work outside with less tiredness.Copyright

A Metamodel of Evaluation in Systems Engineering: Application to a Mechatronic Design

Abstract Evaluation is present at any phase of the life cycle of a product and each time engineering choices must be made or justified. In order to contribute to supporting the evaluation process, we propose in this paper a meta-model of data needed to evaluate product design within the Systems Engineering framework. Relevant to the MBSE approach, the proposed meta-model should facilitate the communication within a multidisciplinary design team as it highlights the concepts and relations that must be handled and shared by the designers. It could be a basis for the development of a computer assisted evaluation tool for designing interdisciplinary systems such as mechatronics ones. Some concepts and relationships of the proposed meta-model are illustrated in the mechatronic context of designing a module for a power-assisted wheelchair.

A possibilistic framework for identifying the performance to be improved in the imprecise context of preliminary design stage

In a highly competitive and unstable environment, manufacturers must constantly improve their products to remain competitive and satisfy their customers while minimizing incurred costs and risk taking. At the early stages of (re-) engineering, performances forecasting of new product is complicated. Indeed, the impacts of any characteristic change on the product performance are not precisely known. Decision-makers must thus identify the performances to be improved while limiting the engineering efforts spent on innovative upgrades. Although some theoretical worth indexes have been proposed in the multiple criteria literature to estimate the expectable gains when improving changes are planned, they generally rely on non-realistic assumptions on the achievability of the expected improvements. Based on multi-criteria decision analysis techniques and uncertainty theory, this paper proposes an extension of the worth index concept when the likelihood of the expected improvements is not precisely known as it is the case at the preliminary stages of design activities.

A Qualitative Approach to Set Achievable Goals During the Design Phase of Complex Systems

The problem addressed in this paper is “how to set ambitious targets when improving or designing a product while these targets remain within the reach of the manufacturer”. Thus, improvements to be focused on are those which both have a significant positive impact on product performance and correspond to operational changes properly under control by the manufacturer. While some approaches in the literature have already addressed each of the two issues of the improvement problem, few deal with both of them at the same time. In this paper we investigate a qualitative approach that conciliates both points of view as an optimization problem. The notion of interaction between any two objectives to be simultaneously satisfied is central in our framework. An illustrative example related to the design phase of autonomous robot is provided.

Evaluation Process Support in Mechatronics Design

The design of mechatronic systems involves different technical and scientific disciplines and it is often difficult to arbitrate between engineers’ points of view so as to satisfy consumers’ needs. In order to converge to satisfactory tradeoffs, designers have to collaborate although they often can understand neither other designers’ issues nor their solving methods. Thus there is no guarantee each designer has spent the needed effort to reach some global optimum. Moreover, the number of design parameters is generally high and it may be difficult to grasp their influence on the design criteria that even can be contradictory. The purpose of this research is to propose methods and tools in order to help designers to evaluate candidate solutions. At this aim, an original heuristic based approach is proposed to compute non-dominated solution sets i.e. Pareto fronts. The analysis of the candidate solutions is facilitated using Self Organization Maps which provide designers with easy readable two dimensional cards. Our approach is fully illustrated in the case of the design of a 2-Degrees Of Freedom robot.Copyright

Optimising the control parameters in a digital mass flow controller

Abstract Mass Flow Controllers are complex mechatronic devices the design of which involves many techniques and skills in various scientific domains. Due to the slow response time of the sensors that are embedded in such devices, controlling gas flow variations in processes used in semiconductor industry is critical. This paper deals with the mathematical design of a digital controller based on the knowledge of the dynamic characteristics of the open loop system. The proposed control method oversteps the bounds of prior art control methods. Experimental results illustrate the good performance of such a digital controller.