Tip-Over Stability Analysis for a Serial-Parallel Mobile Manipulator Using the MNGR Criterion

For mobile manipulators, tipping-over is one of the most important problems when operating on uneven terrain or manipulating heavy objects. The estimation and evaluation of dynamic stability with an easy-computed measure helps to generate actions to avoid tipping-over. This is particularly important in autonomous systems and in human remotely operated manipulators. Therefore, this research presents a tip-over stability analysis applied to a hybrid mobile manipulator that consists of a mobile platform, a Stewart parallel platform and a serial arm manipulator of three degrees of freedom. This paper evaluates the Mean Normal Ground Reaction (MNGR) criterion for a hybrid mobile manipulator comprising a mobile base, a Stewart parallel platform and a 3-DOF serial arm. The MNGR criterion exhibits low computational complexity while remaining sensitive to top-heaviness. Through simulations and experimental tests, this study demonstrates that dynamically reconfiguring the Stewart platform significantly improves the overall dynamic tip-over stability.