Modeling and Analysis on Servo Adjustment of Bidirectional Variable Displacement Pump in Hydraulic Drive System of the Cutter Head in a Shield Tunneling Machine

Based on introduction of the basic configuration, working features of hydraulic drive system of the cutter head in a shield machine, the internal structure of the bidirectional variable displacement pump, BVDP, as the kernel element in the above hydraulic system, is depicted and compared with the ordinary variable plunger pump. Then the working principle and process of hydraulic pilot operated servo displacement adjustment about the BVDP are discussed in detail, and then the mathematical models and its transfer functions of the positive and negative displacement adjustments are established respectively. Also, the relationships between the primary performance indices such as stability condition, positioning stiffness, steady-state error, as well as initial control pressure and system parameters are analysis and concluded.