Model based trajectory control of a flexible turntable ladder

A turntable ladder mounted on a truck, which is commonly used for fire rescue, can be considered as a hydraulically driven flexible beam of variable length. Given the elasticity of the lightweight ladder, both admissible operating velocity and tracking performance as regards commanded trajectories are limited by excited bending oscillations. In the paper, a trajectory control concept using combined feedforward and feedback control, which also involves an active damping of the first mode of bending oscillations, is presented. The control design is based on a detailed multibody model of the turntable ladder extended by a mathematical model of the hydraulic actuator. The effectiveness of the proposed control approach is shown by selected experimental results from the turntable ladder IVECO DLK 23-12 CS.