A stiffness-matching based evaluation approach for compliance of mechanical systems in shield tunneling machines

As the most important performance, compliance of shield tunneling machines (STM) is defined as the capability to accommodate the sudden change of the load induced by the variable geological conditions during excavation. Owing to the different requirements of the compliant tasks, the existing methods in the robotic field cannot be utilized in the analysis and design of the mechanical system of shield tunneling machines. In this paper, based on the stiffness of the mechanical system and the equivalent contact stiffness of the tunnel face, the tunneling interface-matching index (IMI) is proposed to evaluate the compliance of the machine. The IMI is defined as a metric to describe the coincidence of the stiffness curves of the mechanical system and the tunnel face. Moreover, a tunneling case is investigated in the paper as an example to expound the validation of IMI and the analytical process. In conclusion, the IMI presented here can be served as an appraisement of the capability in conforming to the load fluctuation, and give instructions for the design of the thrust system of shield tunneling machines.