Research On The Technology Of Automatic Trajectory Tracking Control During Shield Tunneling Excavation

Shield machine is a large and high-tech construction equipment specially used for underground tunnel excavation. Functions of cutting and excavating soil, transporting soil, assembling tunnel linings, measuring, orientation and rectifying the deviation are integrated into the machine. Thrust system is a critical part of the shield tunneling machine, which offers the thrust force to push the machine forward. Tasks of the shield steering, orientation and posture adjustment can be achieved by means of properly adjusting the distribution of thrust pressure in corresponding working zones. Taking into account the characteristics of time variable, serious nonlinear, strong coupling, big mutations load and transmission with long distance, the development of comprehensive test rig is an effective means of mastering key technologies of full-face tunneling machine, it also can provide conditions for testing the practical, feasibility and reliability of new theories.The research object of this paper is electro-hydraulic control system of thrust system of the shield tunneling machine, and the main research contents of it are as follows,In the first chapter, the classification, composition and construction principle of the shield tunneling construction methods are firstly introduced, and then the research situation of simulation test platform at home and board are described. Later, composition and principle of two common sets of hydraulic thrust system are illustrated, moreover, a comparative analysis of their respective advantages and disadvantages as well as the difference are carried out. Finally, the research state of pose control at home and board are introduced. Research contents and significance of this subject have been put forward basing on analysis of the deficiencies of the pose correction existing in the current actual construction.In the second chapter, mechanical structure diagram of thrust system is firstly established based on the construction site investigation and schemes comparison. Moreover, kinematics modeling of the thrust system in one thrust stroke under steering or rectifying working condition is presented based on the model. A set of scientific and complete orientation and posture rectification strategies has been put forward to overcome the deficiency of the conventional methods and achieve the optimal rectification control of shield machine. Then by combining the optimal rectification strategies with construction and structure parameters of a common kind of shield machine, numerical calculation results under several typical working conditions are developed at last.In the third chapter, scheme selection of the hydraulic load simulation of thrust system and principle of hydraulic thrust system test rig of shield machine are illustrated at first. By establishing the AMESim simulation model of the thrust system, validity of hydraulic load simulation model is verified preliminary, and then simulation researches on regulation characteristic of PID algorithm using in thrust pressure and thrust speed are carried out. Later, design and realization method of trajectory and attitude compound controller are expounded. In allusion to a particular excavation condition, a preliminary simulation analysis of the automatic trajectory tracking control by using the fixed-value compensation control as feed-forward controller and PID as feedback controller is discussed at last.In the fourth chapter, the hardware and software design of the electrical part of the existing hydraulic thrust system simulation test platform is designed according to the monitoring demands. Tasks of improvement in the hardware contains components selection, design and debugging work of manual/automatic electric control switch circuit by using the combination circuit of photoelectric coupler, relay and diode. The software design includes given of switch quantity signal, human machine interface, measurement and control programs by use of software Labview, and the simulation study of two-way high-speed count of the barrows encoder by using the software Proteus and Keil uVision3.In the fifth chapter, the common control algorithms applied in the precise control of thrust force and speed are developed by using the combination methods of the theoretical analysis, simulation and experimental study. Further, through listing several common construction conditions and geological load conditions, the automatic trajectory tracking control effect of multi-actuators under different working modes are carried out. The experimental results show that, when the shield machine works in the gentle changing soil layer, the proposed control algorithm can fulfill the automatic trajectory tracking control with short response time and small overshoot and steady error, which can meets the requirements of common tunnel construction projects.