Study on the linear dynamic model of shield TBM cutterhead driving system

This paper establishes a generalized linear time-varying (G-LTV) dynamic model of the shield tunnel boring machine (TBM) cutterhead driving system, and the corresponding linear time-varying multiple-input and multiple-output (MIMO) state-space model is also presented. The dynamic model reveals that the number of the driving motor can affect the performances of the shield TBM driving system. The dynamic model is a basis of the multiple motors synchronous control, and it is also a basis of faults diagnosis of shield TBM cutterhead driving system. Through maximizing the shield TBM cutterhead´s speed-torque gain of the single induction motor or shield TBM cutterhead´s speed-total-torque gain of all induction motors, we obtain the optimum transmission ratio (OTR) and the optimum reduction ratio (ORR) of the shield TBM cutterhead driving system. The OTR and ORR reveal that: in the conditions of the quantitative motor output torque, the shield TBM cutterhead can acquire higher rotation speed, thus selecting the suitable TR or RR makes the driving system improve performances. Analyzing the G-LTV model of the driving system, it finds that the load torque and the number of active pinions or driving motors have an impact on the dynamic performances of cutterhead driving system. The mechanical transmission structure with multiple active pinions is simulated by automatic dynamic analysis of mechanical systems (ADAMS) software that confirms the driving system´s performances of shield TBM cutterhead are also affected by the load torque, active pinions´ speed inconsistency, and the number of active pinion or the number of driving motor.