Load observer-based integral sliding mode trajectory tracking control of shield automatic tunnelling via hyperbolic tangent function

摘要

This paper studies a load observer-based integral sliding mode trajectory tracking control with the aid of hyperbolic tangent function for a very large shield tunnelling machine in a complicated underground environment. With an introduced equivalent friction and resistant moment, a dynamic model is proposed to reveal the position and attitude behaviours in addition to the coupled effects between the multi-actuators and the various load forces acting on the shield body. Furthermore, the overall system is considered to be two subsystems, i.e., the attitude control and the electrohydraulic thrusting subsystems, for purpose of decreasing the controllers design difficulty. Particularly, an integral sliding mode manifold by replacing the traditional signum with the hyperbolic tangent function is addressed to construct the system controllers, which can attenuate the chattering as much as possible. In addition, the updated laws are adopted to observe the uncertain load as well. Numerical simulations are included to illustrate the improved performances of the closed-loop system with the proposed controllers.