Use this URL to cite or link to this record in EThOS:
Title: Manual assembly modelling and simulation for ergonomics analysis
Author: Ding, Ziyun
Awarding Body: University of Liverpool
Current Institution: University of Liverpool
Date of Award: 2013
Availability of Full Text:
Access from EThOS:
Access from Institution:
In manufacturing industry, although automation techniques have been employed widely, many tasks still require the flexibility and intelligence of human operators, especially in the product assembly process. Insufficient industrial ergonomics in the assembly process will cause the health problems and quality and productivity losses, ultimately increase costs of the final product. The purpose of this thesis is to integrate ergonomic considerations into the manual assembly process modelling and simulation in order to provide product/process design changes before their physical prototyping. In this research, a state-of-the-art commercial software tool - DELMIA - is adopted for the ergonomics simulation and analysis. Associated with its capabilities for the ergonomics solution, a series of human related issues in the manual assembly process is simulated and studied in order to demonstrate the benefits of a virtual assembly approach to the product deign, workplace deign, time and energy saving. Due to the poor repeatability and reproducibility of digital human postures in DELMIA manipulation, a posture prediction method is developed aiming at a practical and precise ergonomics analysis. A 10-degrees-of-freedom, 4-control-points digital human model concerned with assembly features and human diversity is established. The multi-objective optimisation method is applied to assembly posture prediction in which optimisation objectives (i.e. joint discomfort and metabolic energy expenditure) and constraints corresponding to manual assembly tasks are proposed and formulated. Following the verification of the posture prediction method, a series of posture strategies under different assembly conditions are investigated towards more comfortable and energy-efficient assembly postures. Thus far, the consideration on assembly operators in assembly sequencing is insufficient though it plays a key role in the integrative product and process design. In this research, the use of new ergonomic constraints into assembly sequencing optimisation is proposed. Feasible assembly sequences are generated and evaluated based on the product geometry, assembly workstation layout, operator characteristics and working posture. A new Liverpool Assembly Sequence Planning System (LASP) is developed to achieve the integration by applying two evaluation criteria, i.e. visibility criterion, accessibility criterion or both. With LASP, possible design faults with respect to restricted visibility and obstructed accessibility is obtainable during the early design stage. Meanwhile, the optimum sequences are provided to operators automatically for ease of manual assembly, facilitating higher assembly quality and efficiency.
Supervisor: Hon, Bernard; Short, Tim Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: TA Engineering (General). Civil engineering (General)