22nd Congress of International Council of the Aeronautical Sciences, Harrogate, UK, 28 August - 1st September, 2000
Paper ICAS 2000-5.9.2

ERROR BUDGETING AND THE DESIGN OF LARGE AEROSTRUCTURES

R. Odi, G. Burley, S. Naing, A. Williamson, J. Corbett
School of Industrial and Manufacturing Science, Cranfield University, UK

Keywords: error budgeting, design methods, jigless assembly, aerostructures

Traditionally the manufacture of both military and civil aircraft has relied on the use of fixed tooling designed specifically for individual product types (ECATA 1995 [1]). Coproduction of aircraft is resulting in demands for higher standards of manufacturing quality to ensure that parts and sub-assemblies from different countries are compatible and interchangeable. As a results, the existing manufacturing and assembly methods using large numbers of dedicated jigs and tools is now seen as being commercially undesirable, and technically flawed (Burley and Corbett, 1998 [2]). Error budgeting has been succesfully used for the design of precision machines [3, 4]. According to Donaldson [5], “… an error budget is a system analysis tool, used for prediction and control of the total error of a system at the design stage for systems where accuracy is an important measure of performance”. The Jigless Aerospace Manufacture (JAM) project is a three-year project supported by the UK Engineering and Physical Sciences Research Council (EPSRC) and aims to investigate the significant scientific, technological and economic issues to enable a new design, manufacture and assembly philosophy based on eliminating or minimising product specific jigs, fixtures and tooling. As part of this on-going research programme, it proposed to investigate the use of error budgeting as a tool to enable the design of large aerostructures which would be easily assembled without recourse to expensive jigs and fixtures. This technique has the potential to allow the comparison of several concepts and configurations early in the design process and so help the selection process as well as highlighting areas where redesign should be considered at the detail design stage. This paper will present the results of the investigation, assessing its potential and limits as well as its suitability for the design of large aerospace structures.

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