Modelling and dynamic characterisation of a double-pendulum overhead crane carrying a distributed-mass payload

In industries, cranes are commonly used for transportation of a distributed-mass payload (DMP). However, analysis of the dynamic characteristics of such a system is limited since most of the research work considered a point-mass payload. This paper presents modelling and analysis of dynamic characteristics of a double-pendulum overhead crane carrying a DMP with and without payload hoisting. Nonlinear dynamic models representing the crane in both scenarios are derived. The effects of varying cable lengths, and carrying different payload masses and lengths on the dynamics of hook and payload oscillations are also studied. Simulations are performed to observe the dynamic characteristics of the crane under several conditions, and experiments are carried out to validate the theory and simulation results, and to assess the accuracy of the derived nonlinear dynamic equations. The results demonstrate that the payload oscillation is significantly affected by changes in the cable lengths and DMP parameters. In addition, satisfactory agreements between simulation and experimental results are achieved, which indicate validity of the nonlinear models and good compliance with the theory. It is envisaged that the dynamic characteristic analyses of the crane can be beneficial in designing efficient controllers, especially in suppressing DMP oscillation.