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Optimization Design Research on Hydraulic System for a Tunnel Segment Assembly Device of Shield Machine

The segment assembly system of shield machine is a multi-degree-of-freedom system by hybrid control using electricity and hydraulics. Its control method has great influence on the stability of the whole machine, the stability of the surface and the work efficiency of its system. In order to reduce surface settlement, the assembly machine must be efficient, stable and reliable in its work. The assembly system has six degrees of freedom, and control system of degree of freedom relies on a hydraulic system. Whether it is a translational circuit, a circumferential circuit, a radial circuit, a fine-tuning circuit, a locking circuit and so forth, each circuit achieves a corresponding function by controlling an actuator in the hydraulic system. The system is a hydraulic working system, which uses PLC to control hydraulic cylinders to realize the handling of material segments. The multi-degree of freedom system can realize various movement postures of the segments and position and lock the segments. This paper analyzed the mechanism of its multi-degree-of-freedom series-parallel system. The influencing factors of the weak link of the parallel multi-degree-of-freedom system are analyzed and modified. The research of the fine-tuning system was also carried out, and the control precision and stability of the system were improved through analyzing the influencing factors and optimizing the design of the fine-tuning system. It provides reasonable optimization methods and solutions for the hydraulic system design of various shield machines through the transformation and redesign of the hydraulic system.