Pose and trajectory control of shield tunneling machine in complicated stratum

The present study is focused on developing a method for controlling the pose and trajectory of a shield tunneling machine (STM) applied in complicated stratum. Lacking method to determine target motions of thrust cylinders and suitable electro-hydraulic control system are major restrictions for the STM to realize automatic pose control. To overcome these bottlenecks, a mathematical method for determining the target motions of thrust cylinders is proposed based on kinematic analysis of the thrust mechanism. With this method, target motions of thrust cylinders when the STM excavates along any specific curves can be obtained and used as the input signal of the pose control system. A multi-cylinder control system is proposed based on master/slave control strategy to control the length of each kinematic chain in order to adjust the pose of the thrust mechanism. Experiments are carried out to evaluate the performances of this control system. The experimental results verify that the proposed pose control system is effective in controlling the pose and trajectory of the shield machine no matter it advances along a straight or a curved tunnel axis. Considering the complex loads during the experiments, the proposed system has great potential for applying in practical tunnel construction.