Research Overview

The overall aim of the research in the Group is improvement in flexibility and to reduction of lead times during design, process development and manufacture of complex engineering products.

A particular focus has been in dealing with free-form engineering parts defined using NURBS, as the main modelling entity in modern CAD/CAM systems.

The research activities cover a number of areas including:

Geometric modelling
Dimensional metrology using contact and non-contact measuring systems
CAD model updating and reconstruction from point data
Integration between various activities during product and manufacturing process development
Collaborative design and manufacture across the supply chain
Distributed manufacturing planning and control

Design and manufacturing framework

Software tools

The research has resulted in the development of an extensive set of software tools which are being used as the basis for further research. Functionality includes:

Geometric modelling

Import/export of CAD models in standard exchange formats
Modelling for CAD/CAM using NURBS
- creation of NURBS surfaces
- merging, splitting, reparameterisation
- tesselation: adaptive sampling and linear interpolation
- curvature analysis
- surface fairing
Triangulation of large data sets (2D and 3D)

CAD based measurement of free-form shapes

CAD based measurement planning
- contact measurement using CMM equipped with touch probe
- non-contact measurement using laser triangulation probes
Robust and efficient registration (alignment) of the measured data and the CAD model
Error analysis and visualisation
Probe radius compensation for contact probes
Simulation of the measurement process
Automatic programming of the CMM

Smooth surface reconstruction

Highly efficient and robust methods for fitting NURBS surfaces to point data Reconstructed CAD model

tolerance based fitting
handles ordered and unordered data
automatic UV parameterisation
ability to ignore unmeasured areas
constrained fitting
outlier removal
integration with major 3D scanners and CAD/CAM software

Advanced geometric techniques

Computation of thickness for CAD models
Medial Axis construction
Implicit models using Set Level and Fast Marching methods

Research Collaboration

The research is largely conducted through collaborative programmes with the UK and European industry, with support from EPSRC and the European Commission.

Industrial partners include: