Dynamic analysis of the simultaneous movement of the jib lifting and crane turning mechanisms

The efficiency of jib cranes largely depends on increasing their productivity when performing loading, unloading, and installation operations. The simultaneous operation of individual mechanisms increases the productivity of jib cranes. The purpose of this study is to construct a mathematical model and perform a dynamic analysis of the crane jib system during the simultaneous operation of the jib lifting and crane turning mechanisms. The presented research is based on methods for constructing discrete dynamic models of a jib crane using second-order Lagrange equations, numerical methods for solving nonlinear ordinary differential equations, which are presented in the form of a computer program, and methods for dynamic analysis of the simultaneous motion of crane mechanisms. The problem of the dynamics of simultaneous motion of the jib lifting and crane turning mechanisms is solved in this article. The crane jib system is represented by a dynamic model with four degrees of freedom, which considers the main motion of the jib lifting and crane turning mechanisms and the oscillation of the cargo on a flexible suspension. As a result of the dynamic analysis, the kinematic, dynamic, and energy characteristics of individual links of the crane jib system are determined during the simultaneous operation of the jib lifting and crane turning mechanisms. The main movement of the drive mechanisms for lifting the jib and crane turning, as well as the low-frequency spatial oscillations of the cargo on a flexible suspension, were investigated. It has been established that the dynamic motion of the mechanisms depends on the character of the change in the driving forces of the drives. Low-frequency oscillations of the cargo on a flexible suspension practically do not dampen and continue throughout the entire movement cycle. To improve the dynamics of simultaneous motion of mechanisms and minimise oscillatory processes of the jib system links, it is recommended to select modes of smooth change of driving forces of drives in transition processes (starting, braking), which ensure the desired movement of executive mechanisms and lead to a reduction in loads.