Stability Evaluation of Mobile Robotic Systems using Moment-Height Measure

Abstract

Due to excessive maneuverability, mobile manipulators which consist of one or more manipulators mounted on a mobile base have attracted much of interest. Tipping-over is one of the most important problems in such systems especially when manipulating heavy objects, also during maneuvers in unknown environment or in rugged terrains. Therefore, estimation and evaluation of dynamic stability with appropriate easy-computed measure throughout the motion of such systems is a challenging task. In this study, various dynamic stability measures are investigated and compared with each other. Next, a new effective measure named as Moment-Height Stability (MHS) measure is presented for wheeled mobile manipulators. The proposed metric is physically meaningful based on principal concepts, and can be implemented with limited low computational effort. The suggested MHS measure can be effectively used for both legged robots and mobile manipulators. Finally, a few case studies are presented to compare the new MHS measure with the main existing measures. The obtained simulation results show the merits of the new proposed MHS measure, in terms of prediction the exact time of instability occurrence, without additional precautions of the other measures which may confine the maneuverability of the system and its operation.