Twist of Looping Single-Cable Suspended Payloads

Cranes are used in a variety of industries including construction, manufacturing, and shipping to movement of suspended payloads. Movement of these suspended payloads often generates oscillations with long settling times reducing the efficiency of these operations. Given the importance of these operations, significant prior work has examined the modeling and control of payload swing oscillations generated by these motions. However, little prior work has examined the twist of suspended payloads. Most of the existing prior works have focused on the twist of systems in which the hook is suspended from the crane by a single, non-looping cable or systems in which the payload is suspended from the crane by multiple independently controlled cables. This work presents a six degree of freedom model using constrained Kane’s equations for a hook and payload suspended from a tower crane by a single looping cable. Grey-box estimation is employed with experimental data collected from tests on a small-scale tower crane to validate the derived non-linear model and determine the damping coefficients associated with swing, roll, pitch, and twist of the hook/payload.