IDA Passivity-Based Trajectory Control of an Overhead Travelling Crane

In this paper, a passivity-based control scheme is proposed for the two main translational axes of an overhead travelling crane to provide an active damping of crane load oscillations. The decentralised control structure consists of independent axis controllers, which are adapted to the varying rope length using gain-scheduling techniques. The tracking capabilities concerning desired trajectories for the crane load in the xyz-workspace can be improved by introducing feedforward control based on an inverse system model. Furthermore, a nonlinear reduced-order disturbance observer is utilised for the compensation of nonlinear friction forces. The achieved control performance is shown by selected experimental results obtained from an implementation on a test rig.