Research Into Electro-Hydraulic Control System For A Simulator Test Rig Of Shield Tunnelling Machine

The shield tunnelling machine is a type of complicated engineering equipment that is widely applied in the underground tunnel excavation, which is related with subjects of machinery, electronics, hydraulics, measurement and control. Based upon the different kinds of geological conditions, each one of shield tunnelling machines has to be designed and manufactured individually. However, the design theory and method of the shield tunnelling machine is not perfect at present, it is necessary to establish a simulator test rig of shield tunnelling machine for simulating the tunnel excavations under the conditions of different local geological structures. In this thesis, a new design theory and a calculation method in the electro-hydraulic control system are proposed to improve the design level of the shield tunnelling machine.Based upon the analysis of the working conditions in the tunnel excavations, a principle design of hydraulic systems for simulator test rig is carried out theoretically with electro-hydraulic proportional control technique. The electro-hydraulic control system of shield thrust system with integration of pressure and flow control is put forward. The control method of both the thrust pressure and the thrust speed is investigated, and the synchronization control of the hydraulic cylinders is also completed. The simulation and experimental results show that the thrust pressure and thrust speed can be controlled through the integration of pressure and flow control technique, and the synchronization precision of the thrust system can be controlled within the range of ±3 mm, which can meet the requirements of the tunnelling process. On the other hand, the earth pressure balance mechanism is analyzed. The earth pressure can be controlled within the range of set value by controlling the revolving speed of the screw conveyor according to the real time feedback of the earth pressure in the working chamber, which can realize the earth pressure balance basically, and the experimental results show that the earth pressure is generally at 20 KPa in the clayey soil. Moreover, the calculation equations of the total thrust force and the torque of the cutting wheel are obtained, and the relationships between the working parameters of the shield and the soils are discussed. The experimental results show that the total thrust force and the torque of the cutting wheel has a good linear relationship, and the thrust force is increased slowly with the increasing of the thrust displacement. These results would provide the theoretical references for the shield design and manufacture.The main content of each chapter is summarized as following:In chapter 1, the history and current research status of the shield tunnelling machine and the simulator test rig are introduced based on a lot of the publications and conference papers. The key techniques of electro-hydraulic control systems of shield tunnelling machine are also described. Consequently, the research and the goal of the project are brought forward.In chapter 2, the electro-hydraulic control systems of the simulator test rig are designed with the proportional electro-hydraulic control technique based on the analyses of the shield tunnelling machines, including the thrust hydraulic system with integration of pressure and flow control technique, the screw conveyor hydraulic system with electric proportional...