Tip-over responses of hydraulic mobile cranes

The aim of this paper is to develop a complete simulation model and study the tip-over responses of mobile cranes. The developed model takes into account all factors that could affect the overturning of truck cranes including: (i) detailed dynamics of the manipulator links and the base that can potentially rock back and forth, (ii) combined vehicle suspension and ground-tire compliance, (iii) condition of the ground under the wheels or the outrigger pontoons, (iv) friction between the outriggers/tires and the ground, (v) spatial motion of load carried, via a rope, by the telescopic boom of the truck crane, and (vi) hydraulic drive system. The model also includes the effect of the presence of the wheels that can support the machine in case of ground failure at any of the outrigger pontoons, and therefore is capable of predicting subsequent responses in case of soil failure under the crane supports. Simulation results are presented to understand tip-over responses of a typical mobile crane in the presence of load lifting, load swivel, ground failure and various ground conditions. The model developed in this paper is shown to be capable of producing detailed information about the machine responses, the reaction forces at crane' supports and the state parameters of drive system to various input scenarios. The acquired information could additionally be used for improving the design of the cranes in general.