Hybrid Control Design for a Robot Manipulator in a Shield Tunneling Machine

In a novel shield tunneling method, the tunnel lining is produced by an extrusion process with continuous shield advance. A robotic manipulator is used to build the tunnel supporting formwork, consisting of rings of steel segments. As the shield of the tunnel-boring machine advances, concrete is continuously injected in the space between the formwork and the surrounding soil. This technology requires a fully automated manipulator, since potential human errors may jeopardize the continuity of the tunneling process. Moreover, the environment is hazardous for human operators. The manipulator has a linked structure with seven degrees of freedom and it is equipped with a head that can clamp the formwork segment. To design and test the controller, a dynamic model of the manipulator and its environment was first developed. Then, a feedback-linearizing hybrid position-force controller was designed. The design was validated through simulation in Matlab/Simulink. Virtual reality visualization was used to demonstrate the compliance properties of the controlled system.