Modeling And Synchronous Control Of TBM Gripping-Thrusting-Regripping System

Tunnel Boring Machine(TBM)is the key equipment for tunnel construction of railway,highway,hydro and civil facilities.TBM has become the first choice equipment in tunnel construction due to the advantages of high speed,high quality,environment friendly and high safety comparing with traditional drilling and blasting method.Gripping-thrusting-regripping(GTR)mechanism is the key transmission component for the TBM to achieve continuously working,which determines the tunneling efficiency and precision.Closely related to “973” project and “863” program,this thesis focuses on an open-type gripping-thrusting-regripping mechanism of TBM,and systematically researches dynamics modelling and synchronizing control.The results are concluded as below.The thesis researches kinematics and dynamics characteristics of the TBM gripping-thrusting-regripping mechanism using lumped parameter model.The topology structure of the GTR mechanism,as well as the driving methods and working principle of the hydraulic cylinder are systematically analyzed.In accordance with different working conditions,equivalent topological configurations are constructed,while the mechanism degree of freedom(DOF)is derived respectively.The topology characteristics are induced and summarized.Furthermore,the analytical models of direct and inverse solution is built,revealing the relationship between the parameters of driving hydraulic cylinders pose and the cutter head pose.The dynamics model of the mechanism is established for the analysis of the system characteristics,and the variation of natural frequency with respect to the stiffness and mass parameters,which provides a reference for the design of the TBM gripping-thrusting-regripping mechanism in the future.To overcome the limitations of Bond Graph on solving spatial problem,AHP is applied to simplify the dynamics model in analysis of impact factors on dynamics response.On the basis of the theory and modelling methods of Bond Graph,the mechanical-hydraulic coupling bond graph is modelled according to the working conditions for the TBM gripping-thrusting-regripping mechanism,as the foundation of rectifying system modelling.In the application of AHP for dynamics impact factors analysis,the thesis analyzed where the contributions to dynamics performance of the TBM thrusting system by the motion along the axial,radial and transmission direction.Results shows that the radial motion has the highest contribution to the system dynamics performance,which is needed to be carefully considered in the system modelling.Regarding that biased boring has direct impact on precision and efficiency of tunnel construction in complex geological conditions,the thesis researches the dynamic performance of rectifying system.Considering the impact of non-linear factors of induction motor,gear pump,proportional pressure valves,hydraulic cylinder,etc.,the mathematical rectifying model has been built for TBM thrusting by bond graph,while the system state-space representation is derived.Grey prediction is applied in traditional PID control regarding the characteristics of working conditions of TBM GTR mechanism.A variable step grey predicting PID(SGPID)control algorithm is proposed for pressure control in hydraulic synchronizing of the thrusting system.Comparing with regular PID control algorithm,SGPID significantly increases the controllability and synchronizing precision of the pressure on the branches.The mechanical-hydraulic coupling dynamics modeling method and control policy proposed in this thesis are supposed to be verified experimentally.Design principle and overall plan of the test-bed are decided according to the test-bed requirements and functions.Based on the force status of TBM under different working conditions,the load simulation devices and surrounding rock simulation mechanical structures of are designed.The TBM scaled model and supporting devices are also designed afterwards.Finally,scaling principle of test-bed parameters is established according to similarity theory.Scaling coefficients of physical dimensions are deduced respectively.Additionally,test-bed key parameters design,blade-head serving component selecting,and parameters design of test-bed hydraulic parts are accomplished.The model and the rectifying control algorithm are verified by experiments on kinematics characteristics of the scaled model and rectifying plans.