This paper addresses the development of an inertial-sensor-based dynamic system for measuring the displacement of PKM (parallel kinematic machine) struts and the tool centre point (TCP) pose. An inherent problem of inertial positioning systems is the growth, with time, of errors in the measured velocity and position; in the system described in this paper they are corrected by using an external reference measurement and Kalman filtering. Through the combination of the inertial data with an external encoder measurement, a velocity profile containing improved dynamic information can be calculated. The key steps required for the integration of the inertial and encoder measurement systems are introduced, these include the formulation of a system and measurement model and Kalman filter estimation and simulation. Experiments were performed with a single PKM-strut test bed for linear movement to simplify and verify the system. The effects of the system on full PKM machine performance was tested using data from the single strut tests on an emulated PKM. The experimental results are presented and analysed.

Purpose-The aim of the paper is to provide an economically viable solution for the blade repair process. There is a continual increase in the repair market, which requires an increased level of specialised technology to reduce the repair cost and to increase productivity of the process. Design/methodology/approach-This paper introduces the aerospace component defects to be repaired. Current repair technologies including building-up and machining technology are reviewed. Through the analysis of these available technologies, this paper proposes an integrated repair strategy through information integration and processes concentration. Findings-Provides detailed description and discussion for the repair system, including 3D digitising system, repair inspection, reverse engineeringbased polygonal modelling, and adaptive laser cladding and adaptive machining process. Originality/value-This paper describes a 3D non-contact measurement-based repair integration system, and provides a solution to create an individual blade-oriented nominal model to achieve adaptive repair process (laser cladding/machining) and automated inspection.

Feature-based CAD/CAM integration is a technology used to realise automatic transmission and conversion of component information among CAD, CAPP and CAM applications. A feature is the medium of information transmission in the integration. Since a process planning downstream application has a different viewpoint from the component designer, feature conversion or feature extraction methodology is used to create a machining feature model based on the design feature model. One of the major difficulties in generating machining features is the preservation of feature integrity because of feature interactivity. The most current research, therefore, focuses on the planar-type form feature conversion. This paper discusses the problem of feature interactivity and proposes a feature-based approach to generating hole-series machining features from a design feature model. Hole-series features are important machining features for gearbox components used in machine tools. These kinds of features cannot be obtained directly from a design feature database. A constraint-based method is developed in this paper to define a hole-series feature model based on the geometric and topological information extracted from the design database. In addition, a STEP file is generated to interface the converted machining feature model with the downstream CAPP application. The implemented feature conversion system is verified by considering its application to some component examples and the developed prototype CAPP system.

Automatic generation of machining information from a design system has been the research focus in feature-based CAD/CAPP/CAM applications for many years. Design data from a CAD model cannot be directly used in a CAPP system due to the difficulties arising from different feature viewpoints in each application and in various feature representations. To create a process-planning model automatically using machine features, feature mapping or conversion is the key issue to solve this problem. This paper addresses the problem of how to convert the design feature representation into machining feature representation in a mathematicalmodel. Design features in the design domain are represented by a set of faces of each feature geometry and a set of attributes such as dimensions and materialfeature. Machining features in the manufacturing domain are represented by a number of faces and relationships between these faces that are meaningful for the process/machining operations. Using a mathematical description of the feature mapping process, machining features can be deduced and formed by the Set Operation, and the difficult problem of feature interaction can be described mathematically and converted in theory. On the basis of feature representations in the design and manufacturing domains, the mathematicalmodel of feature mapping is represented by a mapping function gd m which is a synthesis function of the process mapping functions g1 and g2. The first function, g1, extracts the topological elements of a feature from a design model, and forms its own face model which including an interactive feature topological elements. The second function, g2, groups these extracted elements into a machining feature according to the geometrical relationship between these elements and matches them with the pre-defined machining features. Examples are given in this paper to show the procedure of the feature mapping process. A feature-based CAD/CAPP/CAM integration system is described with the help of the formulation and representation of machining features.

It is important for a feature-based system to preserve feature integrity during feature operation, especially when feature interaction occurs. The paper presents a feature conversion approach to convert design features used in a design model into machining features for the downstream applications. This process includes both form features (geometric information) and non-geometric features conversion. Most researchers have concentrated on geometric information extraction and conversion without tackling the important problem of non-geometric feature information. This paper focuses on the extraction and conversion of feature geometric dimensions and tolerances (GD&T) for downstream machining application. The main barrier to the integration of a feature-based CAD/CAPP/CAM system-feature interaction-is discussed in this paper, which alters design features in their geometries and nongeometric information. How to identify and validate these feature dimensions and tolerances is one of the key issues in feature interaction conversion. The development of robust methodologies for preserving feature integrity for use in process planning application is the main thrust of the work reported in this paper.