Analysis of unplugging as a common disassembly operation

Xu, Shuihao (2024). Analysis of unplugging as a common disassembly operation. University of Birmingham. Ph.D.

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Abstract

Climate change poses a serious existential threat to human societies and the natural environment worldwide. To lessen environmental damage, the circular economy seeks to convert from linear to closed-loop processes in which products, components, and materials circulate for as long as possible at their best value. It is well accepted that remanufacturing, a circular economy strategy that involves returning a product at the end of its service life to its original condition, is economically and environmentally beneficial. Robotising disassembly can make remanufacturing even more cost-effective by removing a substantial proportion of the labour costs associated with dismantling end-of-life products for subsequent processing. As unplugging of press-fitted components is a common operation in disassembly, it is appropriate to investigate how it can be robotised.
For cylindrical plugs and sockets, an unplugging technique, twist-and-pull or twisting-pulling, is proposed to reduce axial friction during the unplugging process. Through theoretical modelling, simulations, and experimental analysis, the interactions among twisting, pulling and axial friction reduction during unplugging are explored. An analysis of the experimental, simulation, and theoretical results confirmed that for small radial interference, twisting and pulling reduces the axial friction and the maximum required unplugging force.
For cuboid plugs and sockets, there are two conditions for the plug: unconstrained and constrained. Correspondingly, two novel disassembly methods, unconstrained wiggling and constrained wiggling, have been proposed. The theoretical models of these unplugging strategies are validated by Finite-Element Modelling. The experimental results prove that for soft plugs and hard sockets, wiggling reduces the axial friction and the maximum required unplugging force.
In conclusion, this thesis discusses three unplugging techniques for two different plug socket shapes to reduce the axial frictional resistance during the unplugging process and enable a robot to perform unplugging easily.

Type of Work:

Thesis (Doctorates > Ph.D.)

Award Type:

Doctorates > Ph.D.

Supervisor(s):