A trajectory tracking control with disturbance-observer of a fire-rescue turntable ladder

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 higher modes. This paper deals with the active oscillation damping of such ladders. For active oscillation damping by feedback the ladder is equipped with a gyroscope additionally to strain gauges. A Luenberger-type observer is used to separate the fundamental oscillation from the high-frequency modes. Due to computational efforts and measurement noise, only the estimated state of the fundamental oscillation is disposed for feedback. The proposed control approach allows damping the fundamental oscillations and asymptotically stabilizing the system around a reference trajectory. Measurement results from the IVECO DLK 55 CS fire-rescue turntable ladder validate the efficiency of the proposed control structure.