Wave based control for anti-swing motion of a high-speed crane system with hoisting

In this paper we propose a wave based control strategy for a gantry crane system with hoisting. The gantry trolley moves horizontally to move a load mass, suspended by a flexible cable, from rest to rest. The cable motion is interpreted as superposed travelling waves with time-varying boundary conditions. The trolley motion launches a wave into the cable, which travels down to the load where it is reflected back towards the trolley, while also accelerating the load. The return wave is obtained from the measured wave signal at the trolley and a motion to absorb it is superposed on the trolley's launch motion. This rapidly reduces the swing while accelerating the load and system. To bring the system to rest again, precisely at a target position, the process is reversed from the mid-manoeuvre point. The effect of load hoisting is here investigated. Hoisting significantly changes the system dynamics, but despite this, the wave-based control strategy still works extremely well, as demonstrated in numerical simulation. The controller can still land the load mass exactly at target and stop it dead, with zero swing.