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Equipe de recherche COPRIN

Rapports d'activité

Overall Objectives

The COPRIN project-team scientific objective is to develop and implement systems solving algorithms based on constraints propagation methods, interval analysis and symbolic computation, with interval arithmetic as the primary tool. The academic goals of these algorithms is to provide certified solutions to generic problems (e.g. to calculate all solutions of a system of equations within a search space) or to manage the uncertainties of the problems (e.g. to provide an enclosure of all solutions of a system of equations whose coefficients are intervals). These academic goals may also be declined in applicative goals. For example we may determine a domain that describes all possible dimensions of a mechanism that has to satisfy a set of performance requirements. Given this domain it will be possible to determine nominal dimensions for the mechanism so that even if there are bounded variations between the real dimensions and the nominal ones, then the real mechanism will still satisfy the requirements: hence we will be able to manage manufacturing uncertainties for the real process.

Our research aims to develop algorithms that can be used for any problem or are specific to a given class of problems, especially problems that are issued from application domains for which we have an internal expertise (such as mechanism theory and robotics).

A key point of these algorithms is that they rely heavily on symbolic pre-processing and formal calculation in order to improve the efficiency of the problem at hand. Our long term goal is to be able to synthesize automatically a specific solver according to the structure of the problem that has to be managed.

Implementation of the algorithms will be performed within the framework of general purpose software such as Scilab, Maple, Mathematica and will be based on the already existing library ALIAS, that are still being developed mostly for internal use.

Since a theoretical complexity analysis of interval analysis based solving algorithms is usually extremely difficult, the efficiency of the algorithm is systematically experimentally evaluated through ALIAS on various realistic test examples.

Dissemination is also an essential component of our activity because interval analysis based methods are not sufficiently known in the engineering and academic communities.

The study of robotics problems is a major focus point of the COPRIN project. In this field our objectives are:

to develop methods for the analysis of existing robots, taking into account uncertainties in their modeling that are inherent to such mechatronic devices

to propose innovative robotic systems

to develop a design methodology for complex robotic systems that guarantees a required level of performance for the real robot. Our methodology aims at providing not a single design solution but a set of solutions offering various compromises among the performances. Furthermore the solutions will be robust with respect to errors in the realization of the real robot (e.g. due to manufacturing tolerances and control errors)

Experimental work and the development of our own prototypes are strategic for the project as they allow us to validate our theoretical work and to discover new problems that will feed in the long term the theoretical analysis developed by the team members.

We have started since five years a strategic move toward assistance robots (see section ). Our long term goal will be to provide robotized devices for assistance, including smart objects, that may help disabled, elderly and handicapped people in their personal life. Our goals for these devices are that

they can be adapted to the end-user and to its everyday environment

they should be affordable and minimally intrusive

they may be controlled through a large variety of simple interfaces

they may eventually be used to monitor the health status of the end-user in order to detect emerging pathology

As this topic is very large and cannot be managed by a single project-team COPRIN has been one of the main proponent for the creation of the "Action d'Envergure National" PAL (Personnal Assistant Living), that has been accepted in 2011 and that is coordinated by D. Daney.

In summary COPRIN has two major research axes, interval analysis and robotics. The coherence of these axis is that interval analysis is a major tool to manage the uncertainties that are inherent to a robotized device, while robotics provides realistic problems which allow us to develop, test and improve interval analysis algorithms.

COPRIN was created in 2002 and therefore has reached the twelve years limit. It will be followed by a new project-team called HEPHAISTOS, that will be focused on assistance robotics.

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