A new Control Strategy for Trajectory Tracking of Fire–Rescue Turntable Ladders

Abstract

Modern fire-rescue turntable ladders are constructed in a lightweight mode to increase their maximum operation velocities, maximum length, and outreach respectively. Hence, the ladder has a limited stiffness and will be more and more subject to oscillations of deflection along with dominant overtones. This paper deals with the active oscillation damping of such ladders. A new feedforward and feedback control strategy is applied. The feedforward control is calculated through system inversion of a multi-body system utilizing its differentially flatness. The design of the feedback is based on partial differential equations (PDE) describing a Euler– Bernoulli model of a beam with a concentrated point mass at the end. The modal representation of the system is constructed based on the analytical form of the eigenfunctions. For active oscillation damping by feedback without a dynamical observer the ladder was equipped with a gyroscope additionally to strain gauges. Due to computational efforts and measurement noise a reduced state vector is disposed for stabilization. The proposed control approach allows damping the fundamental oscillation as well as the first dominant overtone and asymptotically stabilizing the system around the reference trajectory. Measurement results from the IVECO DLK 55 CS fire-rescue turntable ladder validate the good performance of the control.