Trajectory Control Performance Analysis of Excavator-Based Sheet-Piler-System

Sheet-piling process poses the problem of prescribing the pile a fixed trajectory in order to drive it correctly into the ground. When representing the complete system of the supporting boom with hydraulic actuators, the gripper and the vibratory unit, the large number of system variables implies the use of assisted control to allow a human operator to handle the operation. Based on exact kinematic transformation from boom state space variables to cartesian workspace ones, a simple control procedure linking boom variables reduces inputs to only one which determines the advance of the pile in the ground. A numerical model representing an actual industrial system has been developed. It is verified that the resulting trajectory is very stable and is leading to small tracking error in following a prescribed trajectory when compared to manual performance in similar conditions.