Research On Operations Simulation And Evaluation Method Of Ergonomics For Virtual Assembly

To succeed and gain the competitive advantage in today’s fiercely competitive global market, companies must launch new products with higher quality in a shorter time. Meanwhile, the workload of assembly tasks will become heavier and heavier with the production cycle becoming shorter and shorter, which puts forward higher demand for the workers. Assembly process is the last cycle of product to the market, the assembly quality will directly affect the brand image of the company. Manual assembly is still the most viable method for assembly task. The quality of a product largely depends on the experience of worker. The efficiency and healthy of workers will be affected because of the unreasonable assembly scheme or working in the uncomfortable condition for a long time, which will likely lead to error operations, low efficiency. One of the most popular methods to effectively grapple with that problem in advance is to carry out virtual assembly simulation. However, the application of virtual assembly is basically limited to process control and physical simulation stage, research on the simulation of interactive virtual assembly operations has been few studied to date.To investigate the application of virtual assembly simulation and improve ergonomics, we performed the study on the interactive assembly operation simulation including a digital people involved in with the use of the non-powered and/or powered hand tools in a virtual workshop environment based on the DELMIA software. A Comprehensive Evaluation Method for ergonomics based on simulation of virtual assembly operations is proposed, aiming at avoid inadequate working postures, effectively improve assembly quality and shorten the production cycle. The main content of this dissertation as follows:A virtual working environment consensus with the real workshop is built by the use of DELMIA in order to make the virtual assembly simulation and ergonomics analysis more accurately. Based on motion analysis theory, the assembly operations motion level structure is developed, real-time reproduction of the entire assembly operation process is presented. Ultimately, simulation of the self-motion of worker and interactive assembly operation is conducted, which can guide the workshop workers visually.After studying the characteristics of main assembly operations and unfavorable ergonomic working conditions, comfort felt by the workers was redefined by taking account of virtual assembly environment. We developed the assembly evaluation method for assessment of exposure to risk factors during virtual assembly task. A detailed analysis of the impact of assembly operations and evaluation criteria of each index was studied, which laid the foundation for the implementation of multi-level fuzzy comprehensive evaluation of comfort for virtual assembly task.Based on fuzzy comprehensive evaluation theory and AHP, a comprehensive evaluation method of comfort index for Virtual Assembly is constructed to avo id ergonomic problems in the early planning stages of a production line after the research of the weight of the index is determined and selection of membership function of Quantitative indicators is completed. Analysis results of the assembly task could provide scientific data for the optimization and design tasks. Simulation test showed the current assembly operations may result in high risks and potential injuries to the workers during the process of assembling, improvements is need urgently.This paper then proposed improvement scheme of assembly work postures and the surrounding work environment based on the ergonomics analysis and evaluation results. We relieved the worker’s burden by the use of material portage cart, optimizing the transportation route and using the hoist instead of human to accomplish the hoisting task, which lead to safer working environment. Simulation results show that the improved design could avoid inadequate working postures during assembly task performing and effectively improve assembly quality.In this dissertation, the virtual assembly technology is introduced to the assembly process of an industrial manipulator. Details of the virtual assembly simulation process of an industrial manipulator design and its implementation are presented. This proposed method provides great support to the design of assembly process and brings about good change in the ergonomics of machine and system visualization. In the conclusion, the analysis of this instance plays a guiding role in the optimization of human factors engineering.