Research On Visual Servo Control System For Segment Erector Of Shield Tunneling Machine

Segment erector is an important subsystem in shield system.The speed of ring-laying of segments directly affects the efficiency of tunnel excavation.At present,in practical engineering,the multiple processes of segment assembly have realized mechanical automation,and the efficiency of segment assembly has been improved compared with the initial stage.However,in practical engineering,segment posture cannot realize real-time measurement,the pose of the segment can only be estimated through human eyes segment,then manual control handle to complete segment assembling process,this method cannot be established a set of complete closed loop servo control system.At the same time,there are some problems in the actual segment assembly process,such as the unsynchronized lifting mechanism,high speed but large impact torque,and different proficiency of workers,which limit the efficiency of segment assembly.In order to solve the problem of speed and position unsynchronization of the lifting mechanism of segment erector caused by load disturbance or parameter mismatching,this paper designed the modified cross-coupling-architecture using adaptive PID controller(APID)based on sliding mode control(SMC)and synchronous compensator for lifting mechanism of segment erector.At the same time,the position and pose estimation of segments are realized indirectly by placing targets at appropriate positions of segments,and a complete segment assembly system is established by using image based visual servoing method(IBVS).This method has been verified and analyzed in a segment erector test rig.This paper mainly includes two parts of research and experimentation:(1)Design of synchronous control strategy for lifting mechanism of segment erector.In order to solve the problem of speed and position unsynchronization of the lifting mechanism of segment erector.this paper designed the modified cross-coupling-architecture using adaptive PID controller(APID)based on sliding mode control(SMC)and synchronous compensator for lifting mechanism of segment erector.The experimental results reveal that the synchronization error of the adaptive PID controller is lower than the conventional PID controller.and the proposed adaptive PID controller has good robustness to actuator uncertainties.(2)Design of visual servo control system for segment erector.Firstly,the target is placed at the appropriate position of the segment and the real-time pose estimation is realized indirectly by using an industrial camera.Then,the calculation model of the desired position of the preparing segments is established.On the basis of full analysis,the prediction model of the desired position of the segment is established by using machine learning method.Based on conventional image-based visual servoing method(IBVS)and sliding mode control theory(SMC),the P control law was designed as a hybrid PD-SMC control law,and use Lyapunov theory to verify the stability of the system.At the same time,considering the motion coupling effects caused by the camera motion,the step segment strategy is proposed.Finally,a complete method of segment automatic assembly is established.By comparing and verifying three groups of IBVS and hybrid PD-MSC assembly strategies on the segment erector test rig,the results show that the proposed hybrid PD-SMC assembly strategy has shorter assembly time,smoother image trajectory and no obvious chattering phenomenon.