Abstract:

Considering the fact that the attitude of shield during the boring process is mainly controlled by manual adjustment according to personal experience and that the precision of shield boring trajectory mainly depends on personal proficiency, the authors propose the automatic shield attitude control method based on dual closedloop feedback. The automatic shield attitude control method proposed contains a mainloop feedback that updates the tunneling trajectory and a local feedback that controls the velocity of the thrust cylinders. Succedent analysis shows that the localfeedback control is crucial. Therefore, the authors analyze the geometric relation of hydraulic cylinders before and after onering boring based on a sphericalhinge support thrust system, and deduce the mathematical expression of shield attitude and velocity of thrust cylinders on the left and right sides. The authors achieve the simulation of the velocity control system based on fuzzy PID by using AMEsim and MATLAB software, and make the corresponding test based on a thrust simulation test rig. The result indicates that accurate shield attitude can be realized by fuzzy PID control strategy. The paper provides the theoretical foundation and practical basis for further solution of the shield misalignment problem. 

Key words: shield, attitude control, fuzzy PID, thrust hydraulic system