Modelling and control of a knuckle boom crane

Depending on their dynamic properties, cranes can be classified as gantry cranes and rotary cranes. In this paper, we will focus on the so called ‘knuckle boom’ cranes which are among the most common types of rotary cranes. A first result of this paper is to present a complete mathematical model for this kind of crane where it is possible to control the three rotations of the crane and the cable length. On the basis of this model, we propose a nonlinear control law based on energy considerations which is able to perform position control of the crane while damping the oscillations of the load. The corresponding stability and convergence analysis is carefully proved using the LaSalle's invariance principle. The effectiveness of the proposed control approach has been tested in simulation with realistic physical parameters and in the presence of model mismatch.SCOPUS: ar.j