Investigation of a multi-axis precision machine platform for ultraprecision manufacturing: An integrated approach combining multiscale modelling and digital twin and its implementation perspectives

Abstract

This thesis initially presents a scientific approach for investigating aerostatic bearings design, the simulation approach combined with aerostatic bearing slideway design and development is initially presented for modelling and analysis of the static and dynamic performance of single-axis linear motion system. The modelling is developed and implemented by using COMSOLTM MULTIPHYSICS computational environment integrated with MATLAB programming as needed. The work described is fundamental and essential as a basic part of the efforts for developing the simulation-based virtual machine platform and its digital twin. The improved control algorithms are further investigated and developed in this doctoral research, which aims to enhance the scientific understanding of the multi-axis integrated motion control process for precision machine platform design and its industrial UPM application. In this doctoral research, micro cutting mechanics analysis and tool path generation are integrated to support the establishment of the digital twin in a multiscale multiphysics manner. The method is used to evaluate and predict the key parameters of the UPM machine platform in real time. Furthermore, experimental trials for freeform surface machining based on single point diamond turning (SPDT) system are carried out to evaluate and validate the competence and accuracy of motion control algorithms developed working with DT. Industrial case studies on using CFD simulations and integrated design approach for aerostatic bearing slideway and rotary table design and development are further undertaken to generate the aerostatic bearing products design protocols, which also evaluate and validate the aerostatic bearings design modelling and analysis method and the precision of design simulation and analysis tools developed. Shop floor metrology measurements on the precision machine platform are conducted to validate the developed design and simulations against industrial requirements. There are good agreements between the results of simulations and experimental trials, which are further supported by industrial manufacturing data. The effects of air bearing design variables and control system characteristics are investigated by analysing the results from both the industrial trials and simulations.