METHOD FOR REDUCING DYNAMIC LOADS OF CRANES

摘要

A method and related device for reducing resonant vibrations and dynamic loads of cranes, where vertical motion of a pay load is controlled by a boom winch and a hoist winch. In an embodiment, the method includes determining resonance frequencies of the crane boom and pay load from inertia data of the boom and stiffness on at least the boom and hoist ropes, the resonance frequencies including a first frequency and a lower second frequency. In addition, the method includes automatically modifying the motion of the boom winch or the hoist winch to induce a damping inducing winch motion in the boom or hoist winch, by tuning a proportional integral (PI)-type boom winch speed controller or a PI-type hoist winch speed controller. The boom winch speed controller is tuned to absorb energy at the second frequency, the hoist winch speed controller is tuned to absorb energy at the first frequency.

主权项

1. A device for reducing resonant vibrations and dynamic loads of cranes, the device comprising:
a boom winch configured to control a luffing motion of a pivoting boom; and a hoist winch configured to control a vertical distance between a boom tip and a pay load of the crane; a boom winch speed controller coupled to the boom winch; and a hoist winch speed controller coupled to the hoist winch; wherein the device is configured to acquire resonance frequencies of the coupled crane boom and the pay load from at least inertia data of the boom and stiffness data on at least the boom rope and the hoist rope, the resonance frequencies including a first resonance frequency and a second resonance frequency, the second resonance frequency being lower than the first resonance frequency; wherein the boom winch speed controller or the hoist winch speed controller is configured to automatically modify a motion of the boom winch or a motion of the hoist winch, respectively, to induce a damping inducing winch motion; wherein the boom winch speed controller comprises a proportional integral (PI)-type speed controller that is tuned to absorb vibration energy at the second resonance frequency; and wherein the hoist winch speed controller comprises a PI-type speed controller that is tuned to absorb vibration energy at the first resonance frequency.