Research On Efficient Electro-hydraulic Drive Techniques For The Cutterhead Of Shield Tunneling Machine

Shield tunneling machine is an important basic equipment specially designed for the national infrastructure projects.It can achieve a mechanized continuous construction of the tunnel.With improving techniques,shield machines have been widely used.As one of shield machine's key subsystems,cutterhead electro-hydraulic driving system consumes plenty of energy,and its drving performance directly influences construction speed and construction safety.To achieve better efficiency characteristic and better speed characteristic,optimal design and optimal control researches are carried out for the cutterhead electro-hydraulic driving system.The main research contents are as follows:In chapter 1,the operating principle and operating feature of shield machine is firstly introduced.Then,a development status is reviewed about the shield machine,especially about the domestic shield machine.And its cutterhead driving methods are also reviewed and analyzed.For the energy-saving research about cutterhead electro-hydraulic driving system that have been carried out,a detail summary and analysis is made.Based on the previous studies,main research contents of this paper are finally proposed.In chapter 2,a stepless cutterhead electro-hydraulic driving system is developed.The traditional cutterhead electro-hydraulic system is firstly analyzed.Based on its function and feature,a stepless cutterhead electro-hydraulic system is put forward.For this new system,a compensation control method is designed which can achieve a linear control of rotate speed.With this control method,the rated operating space of stepless cutterhead electro-hydraulic system is analyzed by numerical calculation.Besides,loss models are built to draw the efficiency map of the controlled cutterhead hydraulic system.Further analysis reveals that optimization of pipe connecting methods can help to improve system efficiency.Finally,a cutterhead electro-hydraulic system model is build in AMEsim.With this model,the influence of cutterhead's rotational inertia,pipe connecting mode and motor displacement on speed characteristic is analyzed.In chapter 3,an optimized decision method is developed for the cutterhead electro-hydraulic system.Firstly,a cutterhead load characteristic parameter is defined based on traditional cutterhead load parameters.A cutterhead load characteristic forecast method is then designed.Based on the field data of a tunnel,its prediction accuracy is evaluated through numerical calculation.In addition,efficiency of the cutterhead electro-hydraulic system with different electric motor driving pattern is analyzed by experiments.Based on the measured efficiency characteristic and the designed forecast method,a cutterhead mode control strategy is developed.In chapter 4,the performance of optimally controlled cutterhead electro-hydraulic system is analyzed.Five rings(with equal interval)of a tunnel are firstly selected for tunnelling optimization analysis.For the cutterhead electro-hydraulic test bed,optimized electric motor driving pattern is also calculated.Field cutterhead torque and cutterhead speed(after similarity transformation)of the five rings of tunnel,is then applied to the optimized cutterhead electro-hydraulic test bed and unoptimized cutterhead electro-hydraulic test bed.And their energy performance is measured and analyzed.Besides,online driving mode switch method for the cutterhead electro-hydraulic system is analyzed.Experiments are carried out to analyze its electric shock.Simulations are carried out to analyze its speed influence.In chapter 5,the performance of a cutterhead variable-speed-displacement pump controlled motor system(VSDPM)is investigated.As one of its key performance parameters,VSDPM's rated operating space is firstly investigated through modelling and calculation.As another of its key performance parameters,VSDPM's efficiency is then investigated through experiments.Since VSDPM's efficiency changes with the pump's displacement,the efficient displacement is searched at typical working points.With the efficient displacement,we then measure VSDPM's efficiency over its calculated operating space.To analyze its efficiency performance,the efficiency of a variable-displacement pump controlled motor system(VDPM)is measured as a contrast.Besides,VSDPM's stand-by power is measured and analyzed.Finally,a design and drive scheme of cutterhead VSDPM is put forward.In chapter 6,main research contents are summarized and concluded.And some suggestion about the furture study of cutterhead electro-hydraulic driving system is proposed.