SUMMARY

This thesis investigates a tip-over stability of mobile boom cranes with swinging payloads. Base and crane motion presents a tip-over problem. Attaching complex payloads, such as double-pendulum, further complicates the problem. The study begins with a point mass single-pendulum to analyze tip-over stability under different conditions. A tip-over prediction model is developed with a goal of limiting a computational cost to the minimum. Tip-over stability is characterized by the tip-over stability margin method. The crane's tip-over stability is also represented by the maximum possible payload it can carry throughout the workspace. First, a static stability analysis is performed. In this analysis, the mobile boom crane is assumed to be stationary, thus no payload swing. This study provides basic understanding of the relationship between the tip-over stability and the payload mass and the boom configuration. Next, a pseudo-dynamic stability analysis is conducted. This method incorporates the payload swing into the tip-over stability analysis by adding estimated maximum payload swing due to the motion as a fixed constant rather than a variable. To estimate the angles, the differential equations of motion of payload swings from each type of motion input are derived. The thesis then extends the study to the double-pendulum payload. The maximum swing angles estimated for single-pendulum are directly applied to double-pendulum case to simplify the analysis and minimize the computational cost. To validate the tip-over stability analysis methods introduced, a full dynamic multi-body simulation model of a mobile boom crane is developed. The predictions from the previous analysis are verified by the simulation results. The prediction model and the analysis methods in the thesis provide significant tool for practical application of tip-over stability analysis to mobile boom cranes. The experimental results increase the confidence of the study’s accuracy and accountability.